Molecular Cancer Research最新文献

Esophageal squamous cell carcinoma (ESCC) remains a global health challenge. Circadian clock and Maternal embryonic leucine zipper kinase (MELK) play a key role in tumorigenesis. However, a link between circadian clock dysregulation and MELK function in the occurrence and development of ESCC remains elusive. Here, In the in vivo and in vitro systems, we found for the first time that MELK exhibits pronounced circadian rhythms expression in mice esophageal tissue, xenograft model and human ESCC cells. The diurnal differences expression between peak (ZT0) and trough (ZT12) points in normal esophageal tissue is nearly 10-fold. Circadian expression of MELK in ESCC cells was regulated by Bmal1 through binding to the MELK promoter. Supporting this, the levels of MELK were increased significantly in ESCC patients, and was accompanied with altered expression of core clock genes, especially, Bmal1 is prominently upregulated. Most importantly, Bmal1-deleted eliminated the rhythmic expression of MELK, while knockdown of other core genes had no effect on MELK expression. Furthermore, in nude mice with transplanted tumor, the anticancer effect of OTS167 at ZT0 administration is twice that of ZT12. Implications: Our findings suggest that MELK represents a therapeutic target, and can as a regulator of circadian control ESCC growth, with these findings advance our understanding of the clinical potential of chronotherapy and the importance of time-based MELK inhibition in cancer treatment.

Communication between intracellular organelles including lysosomes and mitochondria has recently been shown to regulate cellular proliferation and fitness. The way lysosomes and mitochondria communicate with each other (lysosomal/mitochondrial interaction, LMI) is, emerging as a major determinant of tumor proliferation and growth. About 30% of squamous carcinomas (including squamous cell carcinoma of the head and neck, SCCHN) overexpress TMEM16A, a calcium-activated chloride channel, which promotes cellular growth and negatively correlates with patient survival. We have recently shown that TMEM16A drives lysosomal biogenesis, but its impact on mitochondrial function has not been explored. Here, we show that in the context of high TMEM16A SCCHN, (1) patients display increased mitochondrial content, specifically complex I; (2) In vitro and in vivo models uniquely depend on mitochondrial complex I activity for growth and survival; (3) NRF2 signaling is a critical linchpin that drives mitochondrial function, and (4) mitochondrial complex I and lysosomal function are codependent for proliferation. Taken together, our data demonstrate that coordinated lysosomal and mitochondrial activity and biogenesis via LMI drive tumor proliferation and facilitates a functional interaction between lysosomal and mitochondrial networks. Therefore, inhibition of LMI instauration may serve as a therapeutic strategy for patients with SCCHN. Implications: Intervention of lysosome-mitochondria interaction may serve as a therapeutic approach for patients with high TMEM16A expressing SCCHN.

Few treatment options are available for metastatic uveal melanoma (UM) patients. Although the bispecific tebentafusp is FDA-approved, immunotherapy has largely failed, likely given the poorly immunogenic nature of UM. Treatment options that improve the recognition of UM by the immune system may be key to reducing disease burden. We investigated whether UM has the ability to undergo pyroptosis, a form of immunogenic cell death. Publicly available patient data and cell line analysis showed that UM expressed the machinery needed for pyroptosis, including gasdermins D and E (GSDMD and E), caspases 1, 3, 4, and 8 (CASP1, 3, 4, and 8), and ninjurin1 (NINJ1). We induced cleavage of gasdermins in UM cell lines treated with metabolic inhibitors. In particular, the CPT1 inhibitor, etomoxir, induced propidium iodide uptake, caspase 3 cleavage and the release of HMGB1 and IL-1β, indicating that the observed cleavage of gasdermins led to pyroptosis. Importantly, a gene-signature reflecting CPT1A activity correlated with poor prognosis in UM patients and knockdown of CPT1A also induced pyroptosis. Etomoxir-induced pyroptosis was GSDME-dependent, but GSDMD-independent and a pyroptosis gene-signature correlated with immune infiltration and improved response to immune checkpoint blockade in a set of UM patients. Together, these data show that metabolic inhibitors can induce pyroptosis in UM cell lines, potentially offering an approach to enhance inflammation-mediated immune targeting in metastatic UM patients. Implications: Induction of pyroptosis by metabolic inhibition may alter the tumor immune microenvironment and improve the efficacy of immunotherapy in uveal melanoma.

Patients with class I V600EBRAF-mutant (MT) colorectal cancer exhibit a poor prognosis, and their response to combined anti-BRAF/EGFR inhibition remains limited. An unmet need exits for further understanding the biology of V600EBRAFMT colorectal cancer. We used differential gene expression of BRAFWT and MT colorectal cancer cells to identify pathways underpinning BRAFMT colorectal cancer. We tested a panel of molecularly/genetically subtyped colorectal cancer cells for their sensitivity to the unfolded protein response (UPR) activator BOLD-100. To identify novel combination strategies for BOLD-100, we performed RNA sequencing and high-throughput drug screening. Pathway enrichment analysis identified significant enrichment of the UPR and DNA repair pathways in BRAFMT colorectal cancer. We found that oncogenic BRAF plays a crucial role in mediating the response to BOLD-100. Using a systems biology approach, we identified V600EBRAFMT-dependent activation of the replication stress response kinase ataxia telangiectasia and Rad3-related (ATR) as a key mediator of resistance to BOLD-100. Further analysis identified acute increases in BRAFMT-dependent-reactive oxygen species levels following treatment with BOLD-100, which promoted ATR/CHK1 activation and apoptosis. Furthermore, activation of reactive oxygen species/ATR/CHK1 following BOLD-100 was mediated through the AhR transcription factor and CYP1A1. Importantly, pharmacological blockade of this resistance pathway with ATR inhibitors synergistically increased BOLD-100-induced apoptosis and growth inhibition in BRAFMT models. These results highlight a possible novel therapeutic opportunity for BRAFMT colorectal cancer. Implications: BOLD-100 induces BRAFMT-dependent replication stress, and targeted strategies against replication stress (e.g., by using ATR inhibitors) in combination with BOLD-100 may serve as a potential novel therapeutic strategy for clinically aggressive BRAFMT colorectal cancer.

Cervical cancer severely affects women's health with increased incidence and poor survival for patients with metastasis. Our study aims to investigate the mechanism by which lncRNA LRRC75A-AS1 regulates the epithelial-mesenchymal transition (EMT) of cervical cancer through modulating m6A and ubiquitination modification. In this study, tumor tissues were collected from patients to analyze the expression of LRRC75A-AS1 and SYVN1. Migratory and invasive capacities of HeLa and CaSki cells were evaluated with wound healing and transwell assays. CCK-8 and EdU incor-poration assays were employed to examine cell proliferation. The interaction between LRRC75A-AS1, IGF2BP1, SYVN1, and NLRP3 was evaluated through RNA immunoprecipitation, RNA pull-down, FISH, and coimmunoprecipitation assays, respectively. MeRIP-qPCR was applied to analyze the m6A modification of SYVN1 mRNA. A subcutaneous tumor model of cervical cancer was established. We showed LRRC75A-AS1 was upregulated in tumor tissues, and LRRC75A-AS1 enhanced EMT through activating NLRP3/IL1β/Smad2/3 signaling in cervical cancer. Furthermore, LRRC75A-AS1 inhibited SYVN1-mediated NLRP3 ubiquitination by destabilizing SYVN1 mRNA. LRRC75A-AS1 competitively bound to IGF2BP1 protein and subsequently impaired the m6A modification of SYVN1 mRNA and its stability. Knockdown of LRRC75A-AS1 repressed EMT and tumor growth via inhibiting NLRP3/IL-1β/Smad2/3 signaling in mice. In conclusion, LRRC75A-AS1 competitively binds to IGF2BP1 protein to destabilize SYVN1 mRNA, subsequently suppresses SYVN1-mediated NLRP3 ubiquitination degradation and activates IL1β/Smad2/3 signaling, thus promoting EMT in cervical cancer. Implication: LRRC75A-AS1 promotes cervical cancer progression, and this study suggests LRRC75A-AS1 as a new therapeutic target for cervical cancer.

Poly ADP-ribose polymerase inhibitors (PARPi) are first-line maintenance therapy for ovarian cancer and an alternative therapy for several other cancer types. However, PARPi-resistance is rising, and there is currently an unmet need to combat PARPi-resistant tumors. Here, we created an immunocompetent, PARPi-resistant mouse model to test the efficacy of combinatory PARPi and euchromatic histone methyltransferase 1/2 inhibitor (EHMTi) in the treatment of PARPi-resistant ovarian cancer. We discovered that inhibition of EHMT1/2 resensitizes cells to PARPi. Markedly, we show that single EHMTi and combinatory EHMTi/PARPi significantly reduced PARPi-resistant tumor burden and that this reduction is partially dependent on CD8 T cells. Altogether, our results show a low-toxicity drug that effectively treats PARPi-resistant ovarian cancer in an immune-dependent manner, supporting its entry into clinical development and potential incorporation of immunotherapy. Implications: Targeting the epigenome of therapy-resistant ovarian cancer induces an antitumor response mediated in part through an antitumor immune response.

Resistance to androgen receptor (AR)-targeted therapies represents a major challenge in prostate cancer. A key mechanism of treatment resistance in patients who progress to castration-resistant prostate cancer (CRPC) is the generation of alternatively spliced AR variants (AR-V). Unlike full-length AR isoforms, AR-Vs are constitutively active and refractory to current receptor-targeting agents and hence drive tumor progression. Identifying regulators of AR-V synthesis may therefore provide new therapeutic opportunities in combination with conventional AR-targeting agents. Our understanding of AR transcript splicing, and the factors that control the synthesis of AR-Vs, remains limited. Although candidate-based approaches have identified a small number of AR-V splicing regulators, an unbiased analysis of splicing factors important for AR-V generation is required to fill an important knowledge gap and furnish the field with novel and tractable targets for prostate cancer treatment. To that end, we conducted a bespoke CRISPR screen to profile splicing factor requirements for AR-V synthesis. MFAP1 and CWC22 were shown to be required for the generation of AR-V mRNA transcripts, and their depletion resulted in reduced AR-V protein abundance and cell proliferation in several CRPC models. Global transcriptomic analysis of MFAP1-depleted cells revealed both AR-dependent and -independent transcriptional impacts, including genes associated with DNA damage response. As such, MFAP1 downregulation sensitized prostate cancer cells to ionizing radiation, suggesting that therapeutically targeting AR-V splicing could provide novel cellular vulnerabilities which can be exploited in CRPC. Implications: We have utilized a CRISPR screening approach to identify key regulators of pathogenic AR splicing in prostate cancer.

Hepatocellular carcinoma (HCC) is the most prevalent type of liver cancer, yet the effectiveness of treatment for patients with HCC is significantly hindered by the development of drug resistance to sorafenib. Through the application of accessibility sequencing to examine drug-resistant HCC tissues, we identified substantial alterations in chromatin accessibility in sorafenib-resistant patient-derived xenograft models. Employing multiomics data integration analysis, we confirmed that the key transcription factor TEAD2, which plays an important role in the Hippo signaling pathway, is a key factor in regulating sorafenib resistance in HCC. Functional assays illustrated that TEAD2 plays a role in promoting HCC progression and enhancing resistance to sorafenib. Mechanistically, we demonstrated that TEAD2 binds to the TAK1 promoter to modulate its expression. Furthermore, we established the involvement of TAK1 in mediating TEAD2-induced sorafenib resistance in HCC, a finding supported by the effectiveness of TAK1 inhibitors. Our research highlights that targeting the TEAD2-TAK1 axis can effectively mitigate drug resistance in patients with HCC receiving sorafenib treatment, offering a novel approach for enhancing the treatment outcomes and prognosis of individuals with HCC. Implications: Targeting the TEAD2-TAK1 axis presents a promising therapeutic strategy to overcome sorafenib resistance in HCC, potentially improving treatment outcomes and prognosis for patients.