Pub Date : 2024-06-10DOI: 10.1158/1538-8514.synthleth24-a008
Jing Huang, Xi Zhang, Peng Huang, Basappa Basappa, Tao Zhu, P. Lobie, Vijay Pandey
Prediabetes denotes a condition when blood sugar levels exceed normal thresholds (>7mmol) but have not reached the diagnostic criteria for type 2 diabetes (<11mmol). It positively correlates with diminished progression-free survival and overall survival among women with epithelial ovarian cancer (EOC). This suggests a potential metabolic state associated with prediabetes that may facilitate tumor survival and progression. Moreover, prediabetes is also associated with an increased risk of recurrence and poorer survival outcomes of EOC patients, possibly promoting tumor aggressiveness and resistance to treatment, although the precise mechanisms remain unclear and warrant additional investigation. In this study, we aimed to explore whether prediabetic D-glucose levels accelerate EOC progression and elucidate underlying mechanisms. We also aimed to propose a viable and effective therapy strategy for EOC progression. Various in vitro and ex vivo oncogenic assays were used to assess the effects of prediabetic levels of D-glucose in EOC cells. It was found to stimulate oncogenic phenotypes in EOC cells in a dose-dependent manner. EOC cells exposed to prediabetic levels of D-glucose (8mM) exhibited increased cell survival, enhanced foci formation on monolayer, growth in soft agar, spheroid formation capacity in 3D Matrigel (ex-vivo culture), increased migration and invasion, and resistance to cisplatin compared to those exposed to lower D-glucose doses (4mM). Exposure to 8mM D-glucose led to metabolic alterations associated with cisplatin resistance, including increased D-glucose consumption, elevated ATP production, increased thermogenesis, enhanced glycolytic capacity, and augmented mitochondrial activity. RNA sequencing analysis showed the BCL-2-associated death promoter (BAD) pathway positively correlates with metabolic alterations of EOC cells in 8mM. Prediabetic levels of D-glucose upregulated phosphorylation of BAD at serine (S) 99 residue along with key metabolic enzymes such as ALDH1A1, HK2, PFKP, G6PD, and LDHA. Inhibition of glycolysis with 2-deoxy-D-glucose (2-DG) attenuated 8mM D-glucose effects. Furthermore, forced expression of phosphorylated BADS99 increased oncogenic phenotypes of EOC. The elevated activities of metabolic enzymes associated with BADS99 phosphorylation were observed in EOCs, while this effect was diminished with dephosphorylated BADS99. High-throughput screening identified a combination therapy involving a BADS99 phosphorylation inhibitor and HDAC inhibitors demonstrated higher synergy to stimulate apoptosis in EOC cells. The combined BADS99-HDAC inhibition synergistically enhanced the efficacy of HDAC inhibitors, significantly reducing their IC50 values. It impaired cell survival, viability, anchorage-independent growth, mitochondrial activity, energy production, growth in 3D Matrigel and successfully overcome cisplatin resistance of EOC cell lines and a patient-derived cell line (AFC). This synergistic therapeutic app
{"title":"Abstract A008: Pre-diabetic D-glucose exposure promotes EOC progression and cisplatin resistance: Role of BAD associated pathway and potential therapeutic strategy","authors":"Jing Huang, Xi Zhang, Peng Huang, Basappa Basappa, Tao Zhu, P. Lobie, Vijay Pandey","doi":"10.1158/1538-8514.synthleth24-a008","DOIUrl":"https://doi.org/10.1158/1538-8514.synthleth24-a008","url":null,"abstract":"\u0000 Prediabetes denotes a condition when blood sugar levels exceed normal thresholds (>7mmol) but have not reached the diagnostic criteria for type 2 diabetes (<11mmol). It positively correlates with diminished progression-free survival and overall survival among women with epithelial ovarian cancer (EOC). This suggests a potential metabolic state associated with prediabetes that may facilitate tumor survival and progression. Moreover, prediabetes is also associated with an increased risk of recurrence and poorer survival outcomes of EOC patients, possibly promoting tumor aggressiveness and resistance to treatment, although the precise mechanisms remain unclear and warrant additional investigation. In this study, we aimed to explore whether prediabetic D-glucose levels accelerate EOC progression and elucidate underlying mechanisms. We also aimed to propose a viable and effective therapy strategy for EOC progression. Various in vitro and ex vivo oncogenic assays were used to assess the effects of prediabetic levels of D-glucose in EOC cells. It was found to stimulate oncogenic phenotypes in EOC cells in a dose-dependent manner. EOC cells exposed to prediabetic levels of D-glucose (8mM) exhibited increased cell survival, enhanced foci formation on monolayer, growth in soft agar, spheroid formation capacity in 3D Matrigel (ex-vivo culture), increased migration and invasion, and resistance to cisplatin compared to those exposed to lower D-glucose doses (4mM). Exposure to 8mM D-glucose led to metabolic alterations associated with cisplatin resistance, including increased D-glucose consumption, elevated ATP production, increased thermogenesis, enhanced glycolytic capacity, and augmented mitochondrial activity. RNA sequencing analysis showed the BCL-2-associated death promoter (BAD) pathway positively correlates with metabolic alterations of EOC cells in 8mM. Prediabetic levels of D-glucose upregulated phosphorylation of BAD at serine (S) 99 residue along with key metabolic enzymes such as ALDH1A1, HK2, PFKP, G6PD, and LDHA. Inhibition of glycolysis with 2-deoxy-D-glucose (2-DG) attenuated 8mM D-glucose effects. Furthermore, forced expression of phosphorylated BADS99 increased oncogenic phenotypes of EOC. The elevated activities of metabolic enzymes associated with BADS99 phosphorylation were observed in EOCs, while this effect was diminished with dephosphorylated BADS99. High-throughput screening identified a combination therapy involving a BADS99 phosphorylation inhibitor and HDAC inhibitors demonstrated higher synergy to stimulate apoptosis in EOC cells. The combined BADS99-HDAC inhibition synergistically enhanced the efficacy of HDAC inhibitors, significantly reducing their IC50 values. It impaired cell survival, viability, anchorage-independent growth, mitochondrial activity, energy production, growth in 3D Matrigel and successfully overcome cisplatin resistance of EOC cell lines and a patient-derived cell line (AFC). This synergistic therapeutic app","PeriodicalId":18791,"journal":{"name":"Molecular Cancer Therapeutics","volume":null,"pages":null},"PeriodicalIF":5.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141365313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1158/1538-8514.synthleth24-ia021
Luke Gilbert, Ben Herken
A fundamental question in biology is how a limited number of genes combinatorially govern cellular responses to environmental changes. While the prevailing hypothesis is that relationships between genes, processes, and ontologies could be plastic to achieve this adaptability, quantitatively comparing human gene functional connections between specific environmental conditions at scale is very challenging. Therefore, it remains unclear whether and how human genetic interaction networks are rewired in response to changing environmental conditions. Here, we developed a framework for mapping context-specific genetic interactions, enabling us to measure the plasticity of human genetic architecture upon environmental challenge for ∼250,000 interactions, using cell cycle interruption, genotoxic perturbation, and nutrient deprivation as archetypes. We discover large-scale rewiring of human gene relationships across conditions, highlighted by dramatic shifts in the functional connections of epigenetic regulators (TIP60), cell cycle regulators (PP2A), and glycolysis metabolism. Our study demonstrates that upon environmental perturbation, intra-complex genetic rewiring is rare while inter-complex rewiring is common, suggesting a modular and flexible evolutionary genetic strategy that allows a limited number of human genes to enable adaptation to a large number of environmental conditions. Citation Format: Luke Gilbert, Ben Herken. Environmental challenge rewires functional connections among human genes [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr IA021.
生物学中的一个基本问题是，数量有限的基因如何组合管理细胞对环境变化的反应。虽然普遍的假设是基因、过程和本体之间的关系可以通过塑性来实现这种适应性，但定量比较人类基因在特定环境条件下的功能连接是非常具有挑战性的。因此，目前仍不清楚人类基因相互作用网络是否以及如何随着环境条件的变化而重新布线。在这里，我们开发了一个绘制特定环境基因相互作用图谱的框架，使我们能够以细胞周期中断、基因毒性扰乱和营养剥夺为原型，测量人类基因结构在环境挑战下的∼250,000 种相互作用的可塑性。我们发现人类基因关系在不同条件下发生了大规模的重新布线，突出表现在表观遗传调控因子（TIP60）、细胞周期调控因子（PP2A）和糖酵解代谢的功能连接发生了巨大变化。我们的研究表明，在环境扰动下，复合物内的基因重配很少见，而复合物间的基因重配却很常见，这表明一种模块化和灵活的进化遗传策略使数量有限的人类基因能够适应大量的环境条件。引用格式：卢克-吉尔伯特、本-赫肯环境挑战重塑人类基因之间的功能连接[摘要].In：AACR 癌症研究特别会议论文集：扩展和转化癌症合成漏洞；2024 年 6 月 10-13 日；加拿大魁北克省蒙特利尔。费城（宾夕法尼亚州）：AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr IA021.
{"title":"Abstract IA021: Environmental challenge rewires functional connections among human genes","authors":"Luke Gilbert, Ben Herken","doi":"10.1158/1538-8514.synthleth24-ia021","DOIUrl":"https://doi.org/10.1158/1538-8514.synthleth24-ia021","url":null,"abstract":"\u0000 A fundamental question in biology is how a limited number of genes combinatorially govern cellular responses to environmental changes. While the prevailing hypothesis is that relationships between genes, processes, and ontologies could be plastic to achieve this adaptability, quantitatively comparing human gene functional connections between specific environmental conditions at scale is very challenging. Therefore, it remains unclear whether and how human genetic interaction networks are rewired in response to changing environmental conditions. Here, we developed a framework for mapping context-specific genetic interactions, enabling us to measure the plasticity of human genetic architecture upon environmental challenge for ∼250,000 interactions, using cell cycle interruption, genotoxic perturbation, and nutrient deprivation as archetypes. We discover large-scale rewiring of human gene relationships across conditions, highlighted by dramatic shifts in the functional connections of epigenetic regulators (TIP60), cell cycle regulators (PP2A), and glycolysis metabolism. Our study demonstrates that upon environmental perturbation, intra-complex genetic rewiring is rare while inter-complex rewiring is common, suggesting a modular and flexible evolutionary genetic strategy that allows a limited number of human genes to enable adaptation to a large number of environmental conditions.\u0000 Citation Format: Luke Gilbert, Ben Herken. Environmental challenge rewires functional connections among human genes [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr IA021.","PeriodicalId":18791,"journal":{"name":"Molecular Cancer Therapeutics","volume":null,"pages":null},"PeriodicalIF":5.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141363338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1158/1535-7163.MCT-23-0784
Nimish Gera, Kyle M Fitzgerald, Vijay Ramesh, Purvi Patel, Deepak Kanojia, Federico Colombo, Lena Kien, Simon Aoyama, Lihui Xu, Jussekia Jean, Amit M Deshpande, William C Comb, Thomas Chittenden, Brian P Fiske
Advances in linker payload technology and target selection have been at the forefront of recent improvements in antibody-drug conjugate (ADC) design, leading to several approvals over the last decade. In contrast, the potential of novel ADC technologies to enhance payload delivery to tumors is relatively underexplored. We demonstrate that incorporation of pH-dependent binding in the antibody component of a c-mesenchymal-epithelial transition (MET)-targeting ADC (MYTX-011) can overcome the requirement for high c-MET expression on tumors, an innovation that has the potential to benefit a broader population of patients with lower c-MET levels. MYTX-011 drove fourfold higher net internalization than a non-pH-engineered parent ADC in non-small cell lung cancer (NSCLC) cells and showed increased cytotoxicity against a panel of cell lines from various solid tumors. A single dose of MYTX-011 showed at least threefold higher efficacy than a benchmark ADC in mouse xenograft models of NSCLC ranging from low to high c-MET expression. Moreover, MYTX-011 showed improved pharmacokinetics over parent and benchmark ADCs. In a repeat dose toxicology study, MYTX-011 exhibited a toxicity profile similar to other monomethyl auristatin E-based ADCs. These results highlight the potential of MYTX-011 for treating a broader range of patients with NSCLC with c-MET expression than other c-MET-targeting ADCs. A first-in-human study is ongoing to determine the safety, tolerability, and preliminary efficacy of MYTX-011 in patients with NSCLC (NCT05652868).
{"title":"MYTX-011: A pH-Dependent Anti-c-MET Antibody-Drug Conjugate Designed for Enhanced Payload Delivery to c-MET-Expressing Tumor Cells.","authors":"Nimish Gera, Kyle M Fitzgerald, Vijay Ramesh, Purvi Patel, Deepak Kanojia, Federico Colombo, Lena Kien, Simon Aoyama, Lihui Xu, Jussekia Jean, Amit M Deshpande, William C Comb, Thomas Chittenden, Brian P Fiske","doi":"10.1158/1535-7163.MCT-23-0784","DOIUrl":"https://doi.org/10.1158/1535-7163.MCT-23-0784","url":null,"abstract":"<p><p>Advances in linker payload technology and target selection have been at the forefront of recent improvements in antibody-drug conjugate (ADC) design, leading to several approvals over the last decade. In contrast, the potential of novel ADC technologies to enhance payload delivery to tumors is relatively underexplored. We demonstrate that incorporation of pH-dependent binding in the antibody component of a c-mesenchymal-epithelial transition (MET)-targeting ADC (MYTX-011) can overcome the requirement for high c-MET expression on tumors, an innovation that has the potential to benefit a broader population of patients with lower c-MET levels. MYTX-011 drove fourfold higher net internalization than a non-pH-engineered parent ADC in non-small cell lung cancer (NSCLC) cells and showed increased cytotoxicity against a panel of cell lines from various solid tumors. A single dose of MYTX-011 showed at least threefold higher efficacy than a benchmark ADC in mouse xenograft models of NSCLC ranging from low to high c-MET expression. Moreover, MYTX-011 showed improved pharmacokinetics over parent and benchmark ADCs. In a repeat dose toxicology study, MYTX-011 exhibited a toxicity profile similar to other monomethyl auristatin E-based ADCs. These results highlight the potential of MYTX-011 for treating a broader range of patients with NSCLC with c-MET expression than other c-MET-targeting ADCs. A first-in-human study is ongoing to determine the safety, tolerability, and preliminary efficacy of MYTX-011 in patients with NSCLC (NCT05652868).</p>","PeriodicalId":18791,"journal":{"name":"Molecular Cancer Therapeutics","volume":null,"pages":null},"PeriodicalIF":5.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141296413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1158/1538-8514.synthleth24-ia002
F. Ferguson
K-Ras inhibitor resistance in PDAC is associated with metabolic reprogramming towards a high OXPHOS state. Existing inhibitors of components of the electron transport chain have on-target toxicities that limit their use in the clinic, highlighting an opportunity to develop mechanistically orthogonal approaches. In this talk, I discuss our development of molecular glue degraders that target metabolic vulnerabilities in K-Ras inhibitor resistant PDAC. Citation Format: Fleur M. Ferguson. Overcoming the K-Ras inhibitor resistant cell state in PDAC with molecular glues [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr IA002.
PDAC对K-Ras抑制剂的耐药性与新陈代谢重编程为高OXPHOS状态有关。现有的电子传递链成分抑制剂具有靶向毒性，这限制了它们在临床上的应用，突出了开发机制正交方法的机会。在本讲座中，我将讨论我们针对 K-Ras 抑制剂耐药的 PDAC 的代谢弱点开发的分子胶降解剂。引用格式：Fleur M. Ferguson.用分子胶克服 PDAC 中 K-Ras 抑制剂耐药的细胞状态 [摘要].In：AACR 癌症研究特别会议论文集：扩展和转化癌症合成脆弱性；2024 年 6 月 10-13 日；加拿大魁北克省蒙特利尔。费城（宾夕法尼亚州）：AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr IA002.
{"title":"Abstract IA002: Overcoming the K-Ras inhibitor resistant cell state in PDAC with molecular glues.","authors":"F. Ferguson","doi":"10.1158/1538-8514.synthleth24-ia002","DOIUrl":"https://doi.org/10.1158/1538-8514.synthleth24-ia002","url":null,"abstract":"\u0000 K-Ras inhibitor resistance in PDAC is associated with metabolic reprogramming towards a high OXPHOS state. Existing inhibitors of components of the electron transport chain have on-target toxicities that limit their use in the clinic, highlighting an opportunity to develop mechanistically orthogonal approaches. In this talk, I discuss our development of molecular glue degraders that target metabolic vulnerabilities in K-Ras inhibitor resistant PDAC.\u0000 Citation Format: Fleur M. Ferguson. Overcoming the K-Ras inhibitor resistant cell state in PDAC with molecular glues [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr IA002.","PeriodicalId":18791,"journal":{"name":"Molecular Cancer Therapeutics","volume":null,"pages":null},"PeriodicalIF":5.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141362795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1158/1538-8514.synthleth24-a014
Qiyun Deng, Mehdi Amiri, Anastasija Ana Piric, Yasaman Bagherian, Zilan Li, Sidong Huang, Michael Pollak, Nahum Sonenberg
This abstract is being presented as a short talk in the scientific program. A full abstract is printed in the Proffered Abstracts section (PR011) of the Conference Program/Proceedings. Citation Format: Qiyun Deng, Mehdi Amiri, Anastasija Ana Piric, Yasaman Bagherian, Zilan Li, Sidong Huang, Michael Pollak, Nahum Sonenberg. Inhibiting eIF4E phosphorylation sensitizes triple-negative breast cancer to CDK4/6 inhibition [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr A014.
{"title":"Abstract A014: Inhibiting eIF4E phosphorylation sensitizes triple-negative breast cancer to CDK4/6 inhibition","authors":"Qiyun Deng, Mehdi Amiri, Anastasija Ana Piric, Yasaman Bagherian, Zilan Li, Sidong Huang, Michael Pollak, Nahum Sonenberg","doi":"10.1158/1538-8514.synthleth24-a014","DOIUrl":"https://doi.org/10.1158/1538-8514.synthleth24-a014","url":null,"abstract":"\u0000 This abstract is being presented as a short talk in the scientific program. A full abstract is printed in the Proffered Abstracts section (PR011) of the Conference Program/Proceedings.\u0000 Citation Format: Qiyun Deng, Mehdi Amiri, Anastasija Ana Piric, Yasaman Bagherian, Zilan Li, Sidong Huang, Michael Pollak, Nahum Sonenberg. Inhibiting eIF4E phosphorylation sensitizes triple-negative breast cancer to CDK4/6 inhibition [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr A014.","PeriodicalId":18791,"journal":{"name":"Molecular Cancer Therapeutics","volume":null,"pages":null},"PeriodicalIF":5.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141365525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1158/1538-8514.synthleth24-pr005
M. Lawrence, L. Porter, Nicholas K Choo, E. Sanij, R. Taylor, Richard B. Pearson, Kaylene Simpson, Ross D. Hannan, S. Sandhu, Luc Furic
Monotherapy with PARP inhibitors is effective for the subset of castrate-resistant prostate cancer (CRPC) with defects in homologous recombination (HR) DNA repair. New treatments are required for the remaining tumors, and an emerging strategy is to combine PARP inhibitors with other therapies that induce DNA damage. Here we tested whether PARP inhibitors are effective for HR-proficient CRPC, including androgen receptor (AR)-null tumors, when used in combination with CX-5461, a small molecule that inhibits RNA polymerase I transcription and activates the DNA damage response, and has antitumor activity in early phase I trials. The combination of CX-5461 and talazoparib significantly decreased in vivo growth of patient-derived xenografts of HR-proficient CRPC, including AR-positive, AR-null, and neuroendocrine tumors. CX-5461 and talazoparib synergistically inhibited the growth of organoids and cell lines, and significantly increased the levels of DNA damage. Decreased tumor growth after combination therapy was maintained for 2 weeks without treatment, significantly increasing host survival. Therefore, combination treatment with CX-5461 and talazoparib is effective for HR-proficient tumors that are not suitable for monotherapy with PARP inhibitors, including AR-null CRPC. This expands the spectrum of CRPC that is sensitive to PARP inhibition. We have recently initiated a clinical trial combining CX-5461 with talazoparib in mCRPC patients (REPAIR trial, NCT05425862) to explore this combination in both HR proficient and deficient settings. Citation Format: Mitchell G. Lawrence, Laura H. Porter, Nicholas Choo, Elaine Sanij, Renea Taylor, Richard Pearson, Kaylene J. Simpson, Ross D. Hannan, Shahneen Sandhu, Luc Furic. CX-5461 sensitizes DNA damage repair-proficient castrate-resistant prostate cancer to PARP inhibition [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr PR005.
PARP抑制剂单药治疗对存在同源重组（HR）DNA修复缺陷的耐阉割前列腺癌（CRPC）有效。剩下的肿瘤需要新的治疗方法，一种新兴的策略是将PARP抑制剂与诱导DNA损伤的其他疗法相结合。CX-5461是一种抑制RNA聚合酶I转录和激活DNA损伤反应的小分子，在早期I期试验中具有抗肿瘤活性。CX-5461和talazoparib联用可显著降低HR缺陷型CRPC（包括AR阳性、AR无效和神经内分泌肿瘤）患者衍生异种移植的体内生长。CX-5461 和 talazoparib 能协同抑制器官组织和细胞系的生长，并显著增加 DNA 损伤水平。联合治疗后肿瘤生长的减少可维持2周不需治疗，从而显著提高宿主存活率。因此，CX-5461和talazoparib的联合治疗对不适合PARP抑制剂单药治疗的HR-proficient肿瘤（包括AR-null CRPC）有效。这扩大了对PARP抑制剂敏感的CRPC的范围。我们最近启动了一项临床试验，将CX-5461与talazoparib联合用于mCRPC患者（REPAIR试验，NCT05425862），以探索这种联合疗法在HR熟练和缺陷两种情况下的应用。引用格式：Mitchell G. Lawrence, Laura H. Porter, Nicholas Choo, Elaine Sanij, Renea Taylor, Richard Pearson, Kaylene J. Simpson, Ross D. Hannan, Shahneen Sandhu, Luc Furic.CX-5461 使具有 DNA 损伤修复能力的阉割耐药前列腺癌对 PARP 抑制敏感 [摘要]。In：AACR癌症研究特别会议论文集：扩展和转化癌症合成脆弱性；2024 年 6 月 10-13 日；加拿大魁北克省蒙特利尔。费城（宾夕法尼亚州）：AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr PR005.
{"title":"Abstract PR005: CX-5461 sensitizes DNA damage repair-proficient castrate-resistant prostate cancer to PARP inhibition","authors":"M. Lawrence, L. Porter, Nicholas K Choo, E. Sanij, R. Taylor, Richard B. Pearson, Kaylene Simpson, Ross D. Hannan, S. Sandhu, Luc Furic","doi":"10.1158/1538-8514.synthleth24-pr005","DOIUrl":"https://doi.org/10.1158/1538-8514.synthleth24-pr005","url":null,"abstract":"\u0000 Monotherapy with PARP inhibitors is effective for the subset of castrate-resistant prostate cancer (CRPC) with defects in homologous recombination (HR) DNA repair. New treatments are required for the remaining tumors, and an emerging strategy is to combine PARP inhibitors with other therapies that induce DNA damage. Here we tested whether PARP inhibitors are effective for HR-proficient CRPC, including androgen receptor (AR)-null tumors, when used in combination with CX-5461, a small molecule that inhibits RNA polymerase I transcription and activates the DNA damage response, and has antitumor activity in early phase I trials. The combination of CX-5461 and talazoparib significantly decreased in vivo growth of patient-derived xenografts of HR-proficient CRPC, including AR-positive, AR-null, and neuroendocrine tumors. CX-5461 and talazoparib synergistically inhibited the growth of organoids and cell lines, and significantly increased the levels of DNA damage. Decreased tumor growth after combination therapy was maintained for 2 weeks without treatment, significantly increasing host survival. Therefore, combination treatment with CX-5461 and talazoparib is effective for HR-proficient tumors that are not suitable for monotherapy with PARP inhibitors, including AR-null CRPC. This expands the spectrum of CRPC that is sensitive to PARP inhibition. We have recently initiated a clinical trial combining CX-5461 with talazoparib in mCRPC patients (REPAIR trial, NCT05425862) to explore this combination in both HR proficient and deficient settings.\u0000 Citation Format: Mitchell G. Lawrence, Laura H. Porter, Nicholas Choo, Elaine Sanij, Renea Taylor, Richard Pearson, Kaylene J. Simpson, Ross D. Hannan, Shahneen Sandhu, Luc Furic. CX-5461 sensitizes DNA damage repair-proficient castrate-resistant prostate cancer to PARP inhibition [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr PR005.","PeriodicalId":18791,"journal":{"name":"Molecular Cancer Therapeutics","volume":null,"pages":null},"PeriodicalIF":5.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141366317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1158/1538-8514.synthleth24-ia009
Alan D. D'Andrea
Deficiency of homologous recombination (HR)-mediated DNA repair occurs through genetic or epigenetic inactivation of the BRCA1 and BRCA2 (BRCA1/2) genes. HR-deficiency also provides unique opportunities for targeted therapy, through the mechanism of synthetic lethality, as exemplified by the hypersensitivity of BRCA1/2-mutated tumors to PARP inhibitors (PARPi). To date, several PARP inhibitors have been approved for clinical use. The promising clinical response of patients with germline BRCA1/2-mutations prompted the use of PARPi for patients with somatic BRCA1/2 mutations as well. In addition, these results extended the use of PARPi for various types of ovarian, breast, pancreatic, and prostate tumors with HR defects. PARPi resistance is emerging as the major obstacle to clinical effectiveness in patients with HR-deficient tumors. PARPi resistance results from several independent mechanisms, leading to the restoration of Homologous Recombination and/or Replication Fork stabilization. The absence of alternative options for patients with tumors with innate or acquired resistance underlines the urgency to develop additional therapeutics. More recent studies have identified new synthetic lethal opportunities for BRCA1/2 deficient tumors. Knockout of the genes for POLQ (DNA polymerase theta) or for USP1 (Ubiquitin Specific Protease 1) results in killing of these tumors, and inhibitors of these enzymes are emerging as promising agents for HR-deficient tumors. POLQ and USP1 expression is particularly high in subtypes of breast and ovarian tumors with defects in HR. As a result, POLQi or USP1i in HR-deficient tumors induces cell death. POLQi or USP1i can synergize with PARPi in killing HR-deficient tumors or PARPi-resistant tumors. BRCA1/2 deficient tumors have an increase in single strand DNA gaps (ssGAPs) near replication forks. Treatment with PARPi results in an increase in the size and number for these ssGAPs, ultimately leading to DSBs and cell death. Interestingly, PARPi resistance results, at least in part, from the ability of resistant cells to close the ssGAPs through enhanced POLQ and USP1 activity, thereby providing a rationale for the combination of PARP1, POLQi, and USP1 in HR-deficient cancers. USP1 inhibition was synergistic with PARP and POLQ inhibition in BRCA1-mutant cells, with enhanced ssDNA gap accumulation. Moreover, this synergy was observed in a set of patient-derived ovarian cancer organoids (PDOs), thus confirming the sensitivity of BRCA1-deficient cells to inhibition by these agents. The accumulation of ssDNA gaps after treatment with a USP1i, PARP, or POLQi correlated with the sensitivity to these drugs in all models tested. Ovarian cancer PDOs provide a powerful tool for detecting drug synergy and for rapid in vitro sensitivity testing. The detection of ssDNA gap accumulation may be a useful predictive biomarker for response to DNA Repair inhibitors as monotherapy or in combination in ongoing clinical trials. Citation For
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Pub Date : 2024-06-10DOI: 10.1158/1538-8514.synthleth24-a015
E. Isenhart, Ajay Gupta, Bryan M. Gillard, Kristopher Attwood, Joyce Ohm
Ewing sarcoma (EwS) is a rare and aggressive disease that typically affects the bone of children and young adults. Although there are moderate 5-year survival rates for primary disease, there is a high rate of recurrence and a lack of targeted therapies in this setting. Furthermore, pediatric exposure to chemotherapies leads to an increased risk of long-term complications, including secondary cancers, cardiomyopathy, and infertility. Therefore, there is a desperate need for targeted therapies which improve therapeutic outcomes and reduce exposure to chemotherapy in these patients. Like many pediatric cancers, EwS has a low mutational burden. Instead, it is driven by chromosomal translocation between a FET family member, EWSR1, and an ETS family member, usually FLI1. The EWSR1-FLI1 fusion protein acts as an aberrant and oncogenic transcription factor, disrupting cell cycle control, cell migration, and proliferation. ETS family members in these fusions retain their ability to bind to the SWI/SNF chromatin remodeling complex, further dysregulating DNA methylation and gene expression. Although targeting of the EWSR1 fusion has not yet been successful, these elevated levels of replication stress (RS) present a unique element of vulnerability within the cell. To this end, our lab has previously identified replication stress response (RSR) inhibitors, DDKi and WEE1i, which can be utilized to exploit the characteristic ability of EwS to maintain high levels of replication stress (RS) and push EwS cells into mitotic catastrophe in vitro. Here, we evaluate the efficacy of the replication stress response inhibitors (RSRi) TAK931 (DDKi) and MK1775 (WEE1i) with chemotherapy regimens commonly utilized in the relapsed/refractory setting in vivo. Using cell line derived xenografts in NSG mice, we show that DDKi and WEE1i with irinotecan limits tumor growth significantly more than existing therapy (temozolomide + irinotecan). Dosing schedules are optimized through dosing de-escalation and alternative-day dosing strategies. We further demonstrate the ability of our RSRi combination to effectively limit tumor growth over time in vivo even when irinotecan dosage is decreased. We go on to investigate the RSRi combination in the presence of ultra-low dose irinotecan. Finally, we utilize reduced representation bisulfite sequencing to examine the epigenetic effects of these treatment regimens. Overall, the exploitation of high endogenous replication stress in EwS by targeted RSRi presents a promising potential therapeutic option for this pediatric patient population. Citation Format: Emily Isenhart, Ajay Gupta, Bryan Gillard, Kristopher Attwood, Joyce Ohm. Exploiting endogenous replication stress with a novel targeted therapy in Ewing sarcoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;2
{"title":"Abstract A015: Exploiting endogenous replication stress with a novel targeted therapy in Ewing sarcoma","authors":"E. Isenhart, Ajay Gupta, Bryan M. Gillard, Kristopher Attwood, Joyce Ohm","doi":"10.1158/1538-8514.synthleth24-a015","DOIUrl":"https://doi.org/10.1158/1538-8514.synthleth24-a015","url":null,"abstract":"\u0000 Ewing sarcoma (EwS) is a rare and aggressive disease that typically affects the bone of children and young adults. Although there are moderate 5-year survival rates for primary disease, there is a high rate of recurrence and a lack of targeted therapies in this setting. Furthermore, pediatric exposure to chemotherapies leads to an increased risk of long-term complications, including secondary cancers, cardiomyopathy, and infertility. Therefore, there is a desperate need for targeted therapies which improve therapeutic outcomes and reduce exposure to chemotherapy in these patients. Like many pediatric cancers, EwS has a low mutational burden. Instead, it is driven by chromosomal translocation between a FET family member, EWSR1, and an ETS family member, usually FLI1. The EWSR1-FLI1 fusion protein acts as an aberrant and oncogenic transcription factor, disrupting cell cycle control, cell migration, and proliferation. ETS family members in these fusions retain their ability to bind to the SWI/SNF chromatin remodeling complex, further dysregulating DNA methylation and gene expression. Although targeting of the EWSR1 fusion has not yet been successful, these elevated levels of replication stress (RS) present a unique element of vulnerability within the cell. To this end, our lab has previously identified replication stress response (RSR) inhibitors, DDKi and WEE1i, which can be utilized to exploit the characteristic ability of EwS to maintain high levels of replication stress (RS) and push EwS cells into mitotic catastrophe in vitro. Here, we evaluate the efficacy of the replication stress response inhibitors (RSRi) TAK931 (DDKi) and MK1775 (WEE1i) with chemotherapy regimens commonly utilized in the relapsed/refractory setting in vivo. Using cell line derived xenografts in NSG mice, we show that DDKi and WEE1i with irinotecan limits tumor growth significantly more than existing therapy (temozolomide + irinotecan). Dosing schedules are optimized through dosing de-escalation and alternative-day dosing strategies. We further demonstrate the ability of our RSRi combination to effectively limit tumor growth over time in vivo even when irinotecan dosage is decreased. We go on to investigate the RSRi combination in the presence of ultra-low dose irinotecan. Finally, we utilize reduced representation bisulfite sequencing to examine the epigenetic effects of these treatment regimens. Overall, the exploitation of high endogenous replication stress in EwS by targeted RSRi presents a promising potential therapeutic option for this pediatric patient population.\u0000 Citation Format: Emily Isenhart, Ajay Gupta, Bryan Gillard, Kristopher Attwood, Joyce Ohm. Exploiting endogenous replication stress with a novel targeted therapy in Ewing sarcoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;2","PeriodicalId":18791,"journal":{"name":"Molecular Cancer Therapeutics","volume":null,"pages":null},"PeriodicalIF":5.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141365335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1158/1538-8514.synthleth24-ia001
William R. Sellers
Targeting activated oncogenes is an effective treatment strategy across many cancers now including therapeutics targeting KRAS. Genetic events including DNA damage deficiencies and tumor suppressor mutations require alternative strategies and the concept of synthetic lethality has been applied to these alterations. PARPi inhibitors were a founding member of this class of therapeutics demonstrating enhanced activity in the setting of BRCA-deficiency. By applying large-scale loss-of-function approaches1 we and other discovered the vulnerability to PRMT5 and WRN inhibition imposed by co-deletions of MTAP and CDKN2A, and the MSI+ genotype respectively2,3. Such inhibitors are now in clinical trials. To explore the potential for paralogous genes to act as synthetic lethal gene pairs we enacted dual knockout screens. These early efforts led to the discovery of DUSP4/6 paralog dependence in the setting of BRAF and NRAS mutations in melanoma4. Intriguingly the loss of DUSP4/6 impaired cancer cell viability through the increased activation of ERK highlighting the susceptibility of cancers to pathway activation in addition to the more common sensitivity to pathway inhibition. This inappropriate activation of the ERK signaling pathway, the conflict between EGFR and KRAS activation, the synthetic lethality enacted by TRIM8 knockouts, and the effects of AR agonists on prostate cancer viability, points to a wider than expected vulnerability of cancer to inappropriate gene activation. To systematically identify context-specific gene activation induced lethalities in cancer, we developed methods for enacting gain-of-function perturbations across ∼500 barcoded cancer cell lines. With this approach, we queried the pan-cancer vulnerability landscape upon activating 10 key cancer pathway revealing activation dependencies in MAPK and PI3K pathways. Notably, we discovered novel pathway hyperactivation dependencies in subsets of APC-mutant colorectal cancers where further activation of the WNT pathway by APC knockdown or direct β-catenin overexpression led to robust antitumor effects in xenograft and patient-derived organoid models. These latter discoveries paradoxically point to the residual activity of the APC ubiquitin-ligase complex as a target in APC-mutant CRC5. 1. McDonald, E. R., 3rd et al. Project DRIVE: A Compendium of Cancer Dependencies and Synthetic Lethal Relationships Uncovered by Large-Scale, Deep RNAi Screening. Cell 170, 577-592.e10 (2017). 2. Mavrakis, K. J. et al. Disordered methionine metabolism in MTAP/CDKN2A-deleted cancers leads to dependence on PRMT5. Science 351, 1208–1213 (2016). 3. Chan, E. M. et al. WRN helicase is a synthetic lethal target in microsatellite unstable cancers. Nature 568, 551–556 (2019). 4. Ito, T. et al. Paralog knockout profiling identifies DUSP4 and DUSP6 as a digenic dependence in MAPK pathway-driven cancers. Nat. Genet. 53, 1664–1672 (2021). 5. Chang, L. et al. Systematic profiling of conditional pathway activation ide
针对激活的癌基因是目前许多癌症的有效治疗策略，包括针对 KRAS 的疗法。包括 DNA 损伤缺陷和肿瘤抑制因子突变在内的遗传事件需要替代策略，合成致死的概念已被应用于这些改变。PARPi 抑制剂是这一类疗法的创始成员，在 BRCA 缺失的情况下显示出更强的活性。通过应用大规模功能缺失方法1，我们和其他人发现了 MTAP 和 CDKN2A 共缺失以及 MSI+ 基因型分别导致的对 PRMT5 和 WRN 抑制的脆弱性2,3。此类抑制剂目前已进入临床试验阶段。为了探索同源基因作为合成致死基因对的潜力，我们进行了双重基因敲除筛选。这些早期研究发现，在黑色素瘤 BRAF 和 NRAS 基因突变的情况下，DUSP4/6 对等基因具有依赖性4。耐人寻味的是，DUSP4/6 的缺失会增加 ERK 的活化，从而损害癌细胞的存活能力。ERK信号通路的不适当激活、表皮生长因子受体（EGFR）与KRAS激活之间的冲突、TRIM8基因敲除产生的合成致死率以及AR激动剂对前列腺癌活力的影响，都表明癌症对不适当基因激活的脆弱性比预期的要大。为了系统地确定癌症中基因激活诱导致死的特异性背景，我们开发了在 500 个条码癌细胞系中实施功能增益扰乱的方法。利用这种方法，我们查询了激活 10 个关键癌症通路后的泛癌症脆弱性图谱，发现了 MAPK 和 PI3K 通路的激活依赖性。值得注意的是，我们在APC突变的结直肠癌亚群中发现了新的通路超激活依赖性，在这些亚群中，通过敲除APC或直接过表达β-catenin进一步激活WNT通路，可在异种移植和患者衍生的类器官模型中产生强大的抗肿瘤效果。这些发现矛盾地指出，APC 泛素连接酶复合物的残余活性是 APC 突变型 CRC 的靶点5。1.McDonald, E. R., 3rd et al. Project DRIVE: A Compendium of Cancer Dependencies and Synthetic Lethal Relationships Uncovered by Large-Scale, Deep RNAi Screening.Cell 170, 577-592.e10 (2017).2.Mavrakis, K. J. et al. 蛋氨酸代谢紊乱在 MTAP/CDKN2A 缺失的癌症中导致对 PRMT5 的依赖。Science 351, 1208-1213 (2016).3.Chan, E. M. et al. WRN螺旋酶是微卫星不稳定癌症的合成致死靶点。Nature 568, 551-556 (2019).4.Ito, T. et al. Paralog knockout profiling identifies DUSP4 and DUSP6 as a digenic dependence in MAPK pathway-driven cancers.Nat.Genet.53, 1664-1672 (2021).5.Chang, L. et al. Systematic profiling of conditional pathway activation identifies contextdependent synthetic lethalities.Nat.Genet.55, 1709-1720 (2023).引用格式：William R. Sellers.利用途径激活作为合成致死的一种新形式 [摘要].In：AACR 癌症研究特别会议论文集：扩展和转化癌症合成脆弱性；2024 年 6 月 10-13 日；加拿大魁北克省蒙特利尔。费城（宾夕法尼亚州）：AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr IA001.
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Pub Date : 2024-06-10DOI: 10.1158/1538-8514.synthleth24-pr007
Julia V. Milne, Ebtihal Mustafa, Kenji Fujihara, Eric P. Kusnadi, A. Trigos, N. Thio, Maree Pechlivanis, C. Cabalag, Twishi Gulati, Kaylene Simpson, C. Duong, Luc Furic, Wayne Phillips, Nicholas Clemons
Application of molecular targeted therapies for esophageal adenocarcinoma (EAC) has been limited by a lack of druggable oncogenic drivers. We propose that synthetic lethal interactions may provide new opportunities for targeted therapies in EAC. We have taken an integrated multi-omics approach incorporating Perturb-Seq (CRISPR editing combined with single cell RNA sequencing) and in vivo tumorigenesis assays to perform high-throughput characterisation of >70 high-confidence EAC driver genes, and genome-wide CRISPR-Cas9 knockout screens in isogenic models of EAC tumorigenesis to identify disease relevant synthetic lethal genetic interactions. MS-based proteomics, reverse phase protein arrays, polysome profiling and bulk RNA-sequencing of isogenic models were utilised to interrogate the biology of bona fide EAC drivers and associated driver specific gene dependencies. The overall goals were to (i) enhance our understanding of EAC tumorigenesis, (ii) identify potential opportunities for therapeutic interventions targeting EAC drivers via synthetic lethal-like approaches, and (iii) reduce the complexity of genetic heterogeneity by categorising EAC drivers with similar phenotypic outcomes. Through our approach we have identified complex crosstalk between the tumor suppressor SMAD4 and regulation of mTOR signaling, with specific downstream effects on translational reprogramming in EAC. Mutation or loss of SMAD4 occurs in up to 20% of EAC, but not pre-malignant tissue (Barrett’s esophagus), and is sufficient to promote transformation of pre-malignant cells in our in vivo tumorigenesis model. In this model, xenotransplanted SMAD4-deficient (via CRISPR-Cas9 knockout or shRNA knockdown) Barrett’s metaplasia cells formed invasive, metastatic tumors after a period of latency. SMAD4 deficient cells had downregulated expression of 4E-BP1, which inhibits EIF4E, the cap-dependent translation initiation factor. This was accompanied by increased mTOR activity, including phosphorylation and inactivation of 4EBP1. Moreover, we found that SMAD4-deficient cells preferentially upregulate cap-dependent translation at the expense of IRES mediated translation. Furthermore, perturbation of additional negative regulators of mTOR signaling in combination with SMAD4 knockout exacerbated these effects and accelerated tumorigenesis in vivo. We have extended these findings to a model of Barrett’s esophagus patient-derived organoids (PDOs) and observed increased proliferative potential of our genetically modified PDOs. Finally, analysing gene ontologies for differentially expressed genes from Perturb-seq revealed that driver-dependent transcriptional changes can be categorized into a smaller number of functional pathways allowing us to potentially consider groups of drivers as functional units. This work advances our understanding of EAC tumorigenesis, provides new mechanistic insights into SMAD4-driven transformation as well as novel potential therapeutic avenues for SMAD4-def
{"title":"Abstract PR007: Delineating functional drivers of esophageal adenocarcinoma to identify synthetic lethal interactions","authors":"Julia V. Milne, Ebtihal Mustafa, Kenji Fujihara, Eric P. Kusnadi, A. Trigos, N. Thio, Maree Pechlivanis, C. Cabalag, Twishi Gulati, Kaylene Simpson, C. Duong, Luc Furic, Wayne Phillips, Nicholas Clemons","doi":"10.1158/1538-8514.synthleth24-pr007","DOIUrl":"https://doi.org/10.1158/1538-8514.synthleth24-pr007","url":null,"abstract":"\u0000 Application of molecular targeted therapies for esophageal adenocarcinoma (EAC) has been limited by a lack of druggable oncogenic drivers. We propose that synthetic lethal interactions may provide new opportunities for targeted therapies in EAC. We have taken an integrated multi-omics approach incorporating Perturb-Seq (CRISPR editing combined with single cell RNA sequencing) and in vivo tumorigenesis assays to perform high-throughput characterisation of >70 high-confidence EAC driver genes, and genome-wide CRISPR-Cas9 knockout screens in isogenic models of EAC tumorigenesis to identify disease relevant synthetic lethal genetic interactions. MS-based proteomics, reverse phase protein arrays, polysome profiling and bulk RNA-sequencing of isogenic models were utilised to interrogate the biology of bona fide EAC drivers and associated driver specific gene dependencies. The overall goals were to (i) enhance our understanding of EAC tumorigenesis, (ii) identify potential opportunities for therapeutic interventions targeting EAC drivers via synthetic lethal-like approaches, and (iii) reduce the complexity of genetic heterogeneity by categorising EAC drivers with similar phenotypic outcomes. Through our approach we have identified complex crosstalk between the tumor suppressor SMAD4 and regulation of mTOR signaling, with specific downstream effects on translational reprogramming in EAC. Mutation or loss of SMAD4 occurs in up to 20% of EAC, but not pre-malignant tissue (Barrett’s esophagus), and is sufficient to promote transformation of pre-malignant cells in our in vivo tumorigenesis model. In this model, xenotransplanted SMAD4-deficient (via CRISPR-Cas9 knockout or shRNA knockdown) Barrett’s metaplasia cells formed invasive, metastatic tumors after a period of latency. SMAD4 deficient cells had downregulated expression of 4E-BP1, which inhibits EIF4E, the cap-dependent translation initiation factor. This was accompanied by increased mTOR activity, including phosphorylation and inactivation of 4EBP1. Moreover, we found that SMAD4-deficient cells preferentially upregulate cap-dependent translation at the expense of IRES mediated translation. Furthermore, perturbation of additional negative regulators of mTOR signaling in combination with SMAD4 knockout exacerbated these effects and accelerated tumorigenesis in vivo. We have extended these findings to a model of Barrett’s esophagus patient-derived organoids (PDOs) and observed increased proliferative potential of our genetically modified PDOs. Finally, analysing gene ontologies for differentially expressed genes from Perturb-seq revealed that driver-dependent transcriptional changes can be categorized into a smaller number of functional pathways allowing us to potentially consider groups of drivers as functional units. This work advances our understanding of EAC tumorigenesis, provides new mechanistic insights into SMAD4-driven transformation as well as novel potential therapeutic avenues for SMAD4-def","PeriodicalId":18791,"journal":{"name":"Molecular Cancer Therapeutics","volume":null,"pages":null},"PeriodicalIF":5.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141362673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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