Molecular Cancer Therapeutics最新文献

While cancer immunotherapy has yielded encouraging outcomes in hematological malignancies, it has faced challenges in achieving the same level of effectiveness in numerous solid tumors, primarily because of the presence of immune-suppressive tumor microenvironments (TMEs). The immunosuppressive qualities of the TME have generated considerable interest, making it a focal point for treatments aimed at enhancing immune responses and inhibiting tumor progression. Fibroblast activation protein (FAP), an attractive candidate for targeted immunotherapy, is prominently expressed in the TME of various solid tumors. Interleukin-12 (IL-12), recognized as a key mediator of immune responses, has been explored as a potential candidate for cancer treatment. Nevertheless, initial efforts to administer IL-12 systemically demonstrated limited efficacy and notable side effects, emphasizing the necessity for innovation. To address these concerns, our molecules incorporated specific IL-12 mutations, called IL-12mut, which reduced toxicity. This study explored the therapeutic potential of the FAP-IL-12mut TMEkine™-a novel immunotherapeutic agent selectively engineered to target FAP-expressing cells in preclinical cancer models. Our preclinical results, conducted across diverse murine cancer models, demonstrated that FAP-IL-12mut significantly inhibits tumor growth, enhances immune cell infiltration, and promotes a shift toward a cytotoxic immune activation profile. These findings suggest that FAP-IL-12mut could offer effective cancer treatment strategies.

Improvement of outcome in patients with pancreatic ductal adenocarcinoma (PDAC) requires exploration of novel therapeutic targets. Thus far, most studies of PDAC therapies, including those inhibiting small ubiquitin-like modifications (SUMOylation), have focused on PDAC epithelial cell biology, yet SUMOylation occurs in a variety of cell types. The mechanisms by which SUMOylation impacts PDAC in the context of its tumor microenvironment are poorly understood. We used clinically relevant orthotopic PDAC mouse models to investigate the effect of SUMOylation inhibition using a specific, clinical-stage compound, TAK-981. In contrast to its inhibition of PDAC cell proliferation in vitro, the survival benefit conferred by TAK-981 in vivo is dependent on the presence of T cells, suggesting that induction of adaptive antitumor immunity is an important antitumor effect of SUMOylation inhibition in vivo. To understand how this adaptive antitumor immunity is promoted, we investigated how SUMOylation inhibition in vivo alters major cell types/subtypes and their communications in the PDAC tumor microenvironment by performing transcriptomic analyses at single-cell resolution, which allowed mapping of cells in our orthotopic mouse model to cells in human PDAC tumors based on gene expression profiles. Findings are further validated by flow cytometry, immunofluorescence, IHC, western blots, and qPCR. The single-cell transcriptome dataset provided here suggests several combination strategies to augment adaptive immune responses that are necessary for durable disease control in patients with PDAC.

CD33 (Siglec-3) is a cell surface receptor expressed in approximately 90% of acute myeloid leukemia (AML) blasts, making it an attractive target for therapy of AML. Although previous CD33-targeting antibody-drug conjugates (ADC) like gemtuzumab ozogamicin (GO, Mylotarg) have shown efficacy in AML treatment, they have suffered from toxicity and narrow therapeutic window. This study aimed to develop a novelADCwith improved tolerability and a wider therapeutic window. GLK-33 consists of the anti-CD33 antibody lintuzumab and eight mavg-MMAU auristatin linkerpayloads per antibody. The experimental methods included testing in cell cultures, patient-derived samples, mouse xenograft models, and rat toxicology studies. GLK-33 exhibited remarkable efficacy in reducing cell viability within CD33-positive leukemia cell lines and primary AML samples. Notably, GLK-33 demonstrated antitumor activity at single dose as low as 300 mg/kg in mice, while maintaining tolerability at single dose of 20 to 30 mg/kg in rats. In contrast with both GO and lintuzumab vedotin, GLK-33 exhibited a wide therapeutic window and activity against multidrug-resistant cells. The development of GLK-33 addresses the limitations of previous ADCs, offering a wider therapeutic window, improved tolerability, and activity against drug-resistant leukemia cells. These findings encourage further exploration of GLK-33 in AML through clinical trials.

KRAS is the most frequently dysregulated oncogene with high prevalence in NSCLC, colorectal cancer, and pancreatic cancer. FDA-approved sotorasib and adagrasib provide breakthrough therapies for cancer patients with KRASG12C mutation. However, there is still high unmet medical need for new agents targeting broader KRAS-driven tumors. An emerging and promising opportunity is to develop a pan KRAS inhibitor by suppressing the upstream protein SOS1. SOS1 is a key activator of KRAS and facilitates the conversion of GDP-bound KRAS state to GTP-bound KRAS state. Binding to its catalytic domain, small molecule SOS1 inhibitor has demonstrated the ability to suppress KRAS activation and cancer cell proliferation. RGT-018, a potent and selective SOS1 inhibitor, was identified with optimal drug-like properties. In vitro, RGT-018 blocked the interaction of KRAS:SOS1 with single digit nM potency and is highly selective against SOS2. RGT-018 inhibited KRAS signaling and the proliferation of a broad spectrum of KRAS-driven cancer cells as a single agent in vitro. Further enhanced anti-proliferation activity was observed when RGT-018 was combined with MEK, KRASG12C, EGFR or CDK4/6 inhibitors. Oral administration of RGT-018 inhibited tumor growth and suppressed KRAS signaling in tumor xenografts in vivo. Combination with MEK or KRASG12C inhibitors led to significant tumor regression. Furthermore, RGT-018 overcame the resistance to the approved KRASG12C inhibitors caused by clinically acquired KRAS mutations either as a single agent or in combination. RGT-018 displayed promising pharmacological properties for combination with targeted agents to treat a broader KRAS-driven patient population.

Triple negative breast cancer (TNBC) represents a therapeutic challenge where standard chemotherapy is limited to paclitaxel. MBQ-167, a clinical stage small molecule inhibitor that targets Rac and Cdc42, inhibits tumor growth and metastasis in mouse models of TNBC. Herein, we investigated the efficacy of MBQ-167 in combination with paclitaxel in TNBC pre-clinical models, as a prelude to safety trials of this combination in advanced breast cancer patients. Individual MBQ-167 or combination therapy with paclitaxel was more effective at reducing TNBC cell viability and increasing apoptosis compared to paclitaxel alone. In orthotopic mouse models of human TNBC (MDA-MB-231 and MDA-MB-468), individual MBQ-167, paclitaxel, or the combination reduced mammary tumor growth with similar efficacy, with no apparent liver toxicity. However, paclitaxel single agent treatment significantly increased lung metastasis, while MBQ-167, single or combined, reduced lung metastasis. In the syngeneic 4T1/BALB/c model, combined MBQ-167 and paclitaxel decreased established lung metastases by ~80%. To determine the molecular basis for the improved efficacy of the combined treatment on metastasis, 4T1 tumor extracts from BALB/c mice treated with MBQ-167, paclitaxel, or the combination were subjected to transcriptomic analysis. Gene set enrichment identified specific downregulation of central carbon metabolic pathways by the combination of MBQ-167 and Paclitaxel but not individual compounds. Biochemical validation, by immunoblotting and metabolic Seahorse analysis, shows that combined MBQ-167 and paclitaxel reduces glycolysis. This study provides a strong rationale for the clinical testing of MBQ-167 in combination with paclitaxel as a potential therapeutic for TNBC and identifies a unique mechanism of action.

The emergence of trastuzumab deruxtecan (T-DXd), a new-generation antibody-drug conjugate (ADC), has profoundly altered the therapeutic paradigm for HER2-positive solid tumors, demonstrating remarkable clinical benefits. However, the combined outcomes of T-DXd with immunotherapy agents remain ambiguous. In this study, we introduce Tras-DXd-MTL1, an innovative HER2 targeting ADC that integrates the topoisomerase inhibitor DXd and a toll-like receptor 7 (TLR7) agonist MTT-5, linked to trastuzumab via a GGFG tetrapeptide linker. Mechanistically, Tras-DXd-MTL1 retains the DNA-damaging and cell-killing properties of topoisomerase inhibitors while simultaneously enhancing the immune response within the tumor microenvironment (TME). This is achieved by promoting immune cell infiltration and activating dendritic cells and CD8+T cells via MTT-5. In vivo evaluation of Tras-DXd-MTL1's anti-tumor potency revealed a notably superior performance compared to the T-DXd (Tras-DXd) or Tras-MTL1 in immunocompetent mice with trastuzumab-resistant EMT6-HER2 tumor and immunodeficient mice with JIMT-1 tumor. This improved efficacy is primarily attributed to its dual functions of immune stimulation and cytotoxicity. Our findings highlight the potential of incorporating immunostimulatory agents into ADC design to potentiate antitumor effects and establish durable immune memory, thereby reducing tumor recurrence risks. Therefore, our study offers a novel strategy for the design of immune-activating ADCs and provides a potential approach for targeting solid tumors with different levels of HER2 expression.

Surgical resection followed by radiotherapy (RT) is recommended for malignant meningioma but poor outcome is unavoidable. To improve the efficacy of RT in malignant meningioma, a targeted radiosensitizer could be added. Nicotinamide phosphoribosyltransferase (NAMPT), highly expressed in high-grade meningiomas may have a role in determining the radioresponse. Here, we evaluated the impact of NAMPT inhibition on radiosensitivity in malignant meningioma in vivo and in vitro. IOMM-Lee and TTMM705 cells were treated with NAMPT inhibition (FK866 or shRNA NAMPT) before irradiation. The subsequent clonogenic assay demonstrated significantly increased radiosensitivity. Combination treatment with FK866 and irradiation significantly increased the number of G2/M-phase cells, the percentage of apoptotic cells and the γ-H2A.X level compared to FK866 or RT alone. We examined the effect of NAMPT inhibition on NMI and p53 expression in IOMM-Lee and TTMM705 cells. NAMPT inhibition by FK866 and shRNA treatment increased NMI, p53, CDKN1A and BAX expression. Additionally, we assessed the efficacy of FK866/RT combination treatment in vivo. The combination treatment exhibited increased antitumor efficacy compared to either treatment alone. The Ki-67 level was significantly lower and the p53 and γ-H2A.X level was significantly higher in the combination treatment group than in any of the other three groups. In conclusion, these results indicate that FK866 improves radiosensitivity in malignant meningioma, an effect that may be attributed to the increase in p53 expression.

Persistence of cancer stem cells (CSCs) is believed to contribute to resistance to platinum-based chemotherapy and disease relapse in ovarian cancer, the fifth leading cause of cancer-related death among US women. HOXC transcript antisense RNA (HOTAIR) is a long noncoding RNA (lncRNA) overexpressed in high-grade serous ovarian cancer and linked to chemoresistance. However, HOTAIR impacts chromatin dynamics in ovarian CSCs and how this oncogenic lncRNA contributes to drug resistant disease are incompletely understood. Here we generated HOTAIR knock-out (KO) high-grade serous ovarian cancer cell lines using paired CRISPR guide RNA design to investigate the function of HOTAIR. We show loss of HOTAIR function re-sensitized ovarian cancer cells to platinum treatment and decreased the population of ovarian CSCs. Furthermore, HOTAIR KO inhibited development of stemness-related phenotypes, including spheroid formation ability, as well as expression of key stemness-associated genes ALDH1A1, NOTCH3, SOX9, and PROM1. HOTAIR KO altered both the cellular transcriptome and chromatin accessibility landscape of multiple oncogenic-associated genes and pathways, including the NF-kB pathway. HOTAIR functions as an oncogene by recruiting enhancer of zeste 2 (EZH2) to catalyze H3K27 tri-methylation to suppress downstream tumor suppressor genes, and it was of interest to inhibit both HOTAIR and EZH2. In vivo, combining a HOTAIR inhibitor with an EZH2 inhibitor and platinum chemotherapy decreased tumor formation and increased survival. These results suggest a key role for HOTAIR in ovarian CSCs and malignant potential. Targeting HOTAIR in combination with epigenetic therapies may represents therapeutic strategy to ameliorate ovarian cancer progression and resistance to platinum-based chemotherapy.

The human CMG helicase (Cdc45-MCM-GINS) is a novel target for anti-cancer therapy. Tumor-specific weaknesses in the CMG are caused by oncogene-driven changes that adversely affect CMG function, and a requirement for CMG activity during recovery from replicative stresses such as chemotherapy. Here, we developed an orthogonal biochemical screening approach and identified CMG inhibitors (CMGi) that inhibit ATPase and helicase activities in an ATP-competitive manner at low micromolar concentrations. Structure-activity information, in silico docking, and testing with synthetic chemical compounds indicate that CMGi require specific chemical elements and occupy ATP binding sites and channels within MCM subunits leading to the ATP clefts, which are likely used for ATP/ADP ingress or egress. CMGi are therefore also MCM complex inhibitors (MCMi). Biological testing shows that CMGi/MCMi inhibit cell growth and DNA replication using multiple molecular mechanisms distinct from other chemotherapy agents. CMGi/MCMi block helicase assembly steps that require ATP binding/hydrolysis by the MCM complex, specifically MCM ring assembly on DNA and GINS recruitment to DNA-loaded MCM hexamers. During S-phase, inhibition of MCM ATP binding/hydrolysis by CMGi/MCMi causes a 'reverse allosteric' dissociation of Cdc45/GINS from the CMG that destabilizes replisome components Ctf4, Mcm10, and DNA polymerase-a, -d, -e, resulting in DNA damage. CMGi/MCMi display selective toxicity toward multiple solid tumor cell types with K-Ras mutations, targeting the CMG and inducing DNA damage, Parp cleavage, and loss of viability. This new class of CMGi/MCMi provides a basis for small chemical development of CMG helicase-targeted anti-cancer compounds with distinct mechanisms of action.

Targeted protein degradation (TPD) using the ubiquitin proteasome system (UPS) is a rapidly growing drug discovery modality to eliminate pathogenic proteins. Strategies for TPD have focused on heterobifunctional degraders that often suffer from poor drug-like properties, and molecular glues that rely on serendipitous discovery. Monovalent "direct" degraders represent an alternative approach, in which small molecules bind to a target protein and induce degradation of that protein through the recruitment of an E3 ligase complex. Using an ultra-high throughput cell-based screening platform, degraders of the bromodomain extraterminal protein BRD4 were identified and optimized to yield a lead compound, PLX-3618. In this paper, we demonstrate that PLX-3618 elicited UPS-mediated selective degradation of BRD4, resulting in potent antitumor activity in vitro and in vivo. Characterization of the degradation mechanism identified DCAF11 as the E3 ligase required for PLX-3618-mediated degradation of BRD4. Protein-protein interaction studies verified a BRD4:PLX-3618:DCAF11 ternary complex, and mutational studies provided further insights into the DCAF11-mediated degradation mechanism. Collectively, these results demonstrate the discovery and characterization of a novel small molecule that selectively degrades BRD4 through the recruitment of the E3 substrate receptor, DCAF11, and promotes potent antitumor activity in vivo.