Project description:Patients with advanced soft-tissue sarcomas (STSs) have few therapeutic options. Protein arginine methyltransferase 5 (PRMT5), an anticancer target, has been extensively investigated in recent years in epithelial tumors. To date, no data related to the biological role of PRMT5 inhibition and its potential effect as a treatment in STS have been reported. To investigate the therapeutic potential of PRMT5 targeting in STS, we first evaluated the prognostic value of PRMT5 expression in 2 different cohorts of patients with STS. We then used the potent and selective GSK3326595 (GSK595) compound to investigate the antitumor effect of the pharmacological inhibition of PRMT5 in vitro via MTT, apoptosis, cell cycle, clonogenicity and proliferation assays. In vivo studies were performed with two animal models to evaluate the effects of GSK595 on tumor growth. The mechanisms of action were investigated by RNA sequencing, metabolic pathway analysis, Western blotting and glucose uptake/lactate production assays. High PRMT5 gene expression levels were significantly associated with worsened metastasis-free survival of STS patients. GSK595 decreased the global symmetric dimethylarginine level, the proliferation rate and clonogenicity of STS cell lines in vitro and tumor growth in vivo. Moreover, PRMT5 inhibition regulated aerobic glycolysis through downregulation of key enzymes of glycolysis as well as glucose uptake and lactate production. The present study demonstrated that PRMT5 regulates STS cell metabolism and thus represents a potential therapeutic target for STS. Additional studies in diverse sarcoma subtypes will be essential to confirm and expand upon these findings.
Project description:Patients with advanced soft-tissue sarcomas (STSs) have few therapeutic options. Protein arginine methyltransferase 5 (PRMT5), an anticancer target, has been extensively investigated in recent years in epithelial tumors. To date, no data related to the biological role of PRMT5 inhibition and its potential effect as a treatment in STS have been reported. To investigate the therapeutic potential of PRMT5 targeting in STS, we first evaluated the prognostic value of PRMT5 expression in 2 different cohorts of patients with STS. We then used the potent and selective GSK3326595 (GSK595) compound to investigate the antitumor effect of the pharmacological inhibition of PRMT5 in vitro via MTT, apoptosis, cell cycle, clonogenicity and proliferation assays. In vivo studies were performed with two animal models to evaluate the effects of GSK595 on tumor growth. The mechanisms of action were investigated by RNA sequencing, metabolic pathway analysis, Western blotting and glucose uptake/lactate production assays. High PRMT5 gene expression levels were significantly associated with worsened metastasis-free survival of STS patients. GSK595 decreased the global symmetric dimethylarginine level, the proliferation rate and clonogenicity of STS cell lines in vitro and tumor growth in vivo. Moreover, PRMT5 inhibition regulated aerobic glycolysis through downregulation of key enzymes of glycolysis as well as glucose uptake and lactate production. The present study demonstrated that PRMT5 regulates STS cell metabolism and thus represents a potential therapeutic target for STS. Additional studies in diverse sarcoma subtypes will be essential to confirm and expand upon these findings.
Project description:Patients with advanced soft-tissue sarcomas (STSs) have few therapeutic options. Protein arginine methyltransferase 5 (PRMT5), an anticancer target, has been extensively investigated in recent years in epithelial tumors. To date, no data related to the biological role of PRMT5 inhibition and its potential effect as a treatment in STS have been reported. To investigate the therapeutic potential of PRMT5 targeting in STS, we first evaluated the prognostic value of PRMT5 expression in 2 different cohorts of patients with STS. We then used the potent and selective GSK3326595 (GSK595) compound to investigate the antitumor effect of the pharmacological inhibition of PRMT5 in vitro via MTT, apoptosis, cell cycle, clonogenicity and proliferation assays. In vivo studies were performed with two animal models to evaluate the effects of GSK595 on tumor growth. The mechanisms of action were investigated by RNA sequencing, metabolic pathway analysis, Western blotting and glucose uptake/lactate production assays. High PRMT5 gene expression levels were significantly associated with worsened metastasis-free survival of STS patients. GSK595 decreased the global symmetric dimethylarginine level, the proliferation rate and clonogenicity of STS cell lines in vitro and tumor growth in vivo. Moreover, PRMT5 inhibition regulated aerobic glycolysis through downregulation of key enzymes of glycolysis as well as glucose uptake and lactate production. The present study demonstrated that PRMT5 regulates STS cell metabolism and thus represents a potential therapeutic target for STS. Additional studies in diverse sarcoma subtypes will be essential to confirm and expand upon these findings.
Project description:Background: Hyperactivated protein arginine methyltransferases (PRMTs) are implicated in human cancers. Inhibiting tumor intrinsic PRMT5 was reported to potentiate antitumor immune responses, highlighting the possibility of combining PRMT5 inhibitors (PRMT5i) with cancer immunotherapy. However, global suppression of PRMT5 activity impairs the effector functions of immune cells. Here, we sought to identify strategies to specifically inhibit PRMT5 activity in tumor tissues and develop effective PRMT5i-based immuno-oncology (IO) combinations for cancer treatment, particularly for methylthioadenosine phosphorylase (MTAP)-loss cancer. Methods: Isogeneic tumor lines with and without MTAP loss were generated by CRISPR/Cas9 knockout. The effects of two PRMT5 inhibitors (GSK3326595 and MRTX1719) were evaluated in these isogenic tumor lines and T cells in vitro and in vivo. Transcriptomic and proteomic changes in tumors and T cells were characterized in response to PRMT5i treatment. Results: transcriptomic and proteomic profiling analysis reveals that MRTX1719 successfully reduces activation of the PI3K pathway, a well-documented immune-resistant pathway. It highlights the potential of MRTX1719 to overcome immune resistance in MTAP-loss tumors. Conclusion: Collectively, our results provide a strong rationale and mechanistic insights for the clinical development of MRTX1719-based IO combinations in MTAP-loss tumors.
Project description:Aberrant protein arginine methylation has been observed in multiple cancer types, making it an attractive drug target. Proteins can undergo asymmetric arginine methylation by type I protein arginine methyltransferases (PRMTs), predominately by PRMT1 and to a lesser extent PRMT4, or symmetric arginine methylation by type II PRMTs, predominately PRMT5. Here, we performed targeted proteomics following inhibition of PRMT1, PRMT4, and PRMT5 across cancer cell lines. We found that inhibition of both type I and type II PRMTs suppressed levels of total and phosphorylated ATR protein in cancer cell lines, and down-regulated expression of the ATR gene. Loss of ATR from PRMT inhibition resulted in defective DNA replication stress response activation in following exogenous replication stress. Since PARP inhibitors are known to induce replication stress, we next combined PRMT inhibition with PARP inhibition and found inhibition of PRMT1 or PRMT5 greatly exacerbated PARP inhibitor induced DNA damage. Based on this observation, we assessed the combination of PARP and PRMT inhibition in a panel of cell lines. While inhibition of both type I and type II PRMTs were synergistic with PARP inhibition in both cells with intact and deficient homologous recombination, type I PRMT inhibition resulted in higher toxicity in non-malignant cells. Therefore, we validated the synergy of combined PARP/PRMT5 inhibition in primary patient-derived organoids. Finally, we demonstrate that the combination of PARP and PRMT5 inhibition improves overall survival in both BRCA-mutant and wild-type patient-derived xenograft models without any detectable hematological toxicities typically associated with PARPi combination therapies. Taken together, these results demonstrate that PRMT5 inhibition may be a well-tolerated approach to improve tumor sensitivity to PARP inhibition. .
Project description:To identify the mechanistic underpinning of the anti-tumor activity of PRMT5 inhibition in MCL, we explored transcriptomic profiles of PDX-AA cells treated in vivo for 2 weeks with PRT-382, ibrutinib, or vehicle control (n=3/group).
Project description:Purpose: Patients with advanced soft-tissue sarcomas (STSs) exhibit a poor prognosis and have few therapeutic options. DNA-dependent protein kinase catalytic subunit (DNA-PK) is a multifunctional serine—threonine protein kinase that plays a crucial role in DNA double-strand damage repair via nonhomologous end joining (NHEJ). Experimental design: To investigate the therapeutic potential of DNA-PK targeting in STS, we first evaluated the prognostic value of DNA-PK expression in two large cohorts of patients with STS. We then used the potent and selective DNA-PK inhibitor AZD7648 compound to investigate the antitumor effect of the pharmacological inhibition of DNA-PK in vitro via MTT, apoptosis, cell cycle, and proliferation assays. In vivo studies were performed with patient-derived xenograft models to evaluate the effects of AZD7648 in combination with chemotherapy or ionizing radiation on tumor growth. The mechanisms of sensitivity and resistance to DNA-PK inhibition were investigated by using a genome-wide CRISPR-Cas9 positive screen. Results: DNA-PK overexpression is significantly associated with poor prognosis in patients with sarcomas. Selective pharmacological inhibition of DNA-PK strongly synergizes with radiation- and doxorubicin-based regimen in sarcoma models. By using a genome-wide CRISPR-Cas9 positive screen, we identified genes involved in sensitivity to DNA-PK inhibition. Conclusion: DNA-PK inhibition deserves clinical investigation to improve response to current therapies in patients with sarcoma