Project description:MTAP is an enzyme and found deleted in various cancers, but its role in lung adenoacrcinoma is still unclear. This study sought to investigate the effects of MTAP on the biological behavior and global gene expression profiles in lung adenocacinoma cells. We used expression microarrays to identify the global gene alterations in lung adenocacinoma cell line, CL1-5 cells after ectopically expressing V5-tagged MTAP gene.
Project description:Abstract The aggressive nature and poor prognosis of lung cancer led us to explore the mechanisms driving disease progression. Utilizing our invasive cell-based model, we identified methylthioadenosine phosphorylase (MTAP) and confirmed its suppressive effects on tumorigenesis and metastasis, and patients with low MTAP expression displayed worse overall and progression-free survival. Mechanistically, accumulation of methylthioadenosine substrate in MTAP-deficient cells reduced the level of protein arginine methyltransferase 5 (PRMT5)-mediated symmetric dimethylarginine (sDMA) modification on proteins. Vimentin was revealed as a novel dimethyl-protein with less dimethylation level in response to MTAP loss. The sDMA modification on vimentin reduces its protein abundance and trivially affects its filamentous structure. In MTAP-loss cells, lower sDMA level prevents ubiquitination-mediated vimentin degradation, thereby stabilizing vimentin, contributing to cell invasion. This inverse association of the MTAP/PRMT5 axis with vimentin proteins was clinically corroborated. Taken together, we propose a novel mechanism of vimentin post-translational regulation and provide new insights in metastasis.
Project description:Methylthioadenosine Phosphorylase (MTAP) is a tumor suppressor gene that encodes an enzyme responsible for the catabolism of the polyamine byproduct 5′deoxy-5′-methylthioadenosine (MTA). To elucidate the mechanism by which MTAP inhibits tumor formation, we have created isogenic MTAP+ and MTAP- HT1080 fibrosarcoma cells. In this experiment we have performed expression array analysis on MTAP-, MTAP+, and MTAP+ cells treated with the MTAP inhibitor MT-DADMe-ImmA. Three biological replicates of each sample were grown and analyzed. M- is MTAP-. M+ is MTAP+, and M+I is MTAP treated with inhibitor (48 hours).
Project description:Previous studies implicated PRMT5 as a synthetic lethal target for MTAP deleted (MTAP del) cancers, however, the pharmacological characterization of small molecule inhibitors that recapitulate the synthetic lethal phenotype have not been described. MRTX1719 selectively inhibited PRMT5 in the presence of MTA, which is elevated in MTAP del cancers, and inhibited PRMT5-dependent activity and cell viability with >70-fold selectivity in HCT116 MTAP del compared to HCT116 MTAP WT cells. MRTX1719 demonstrated dose-dependent anti-tumor activity and inhibition of PRMT5-dependent SDMA modification in MTAP del tumors. In contrast, MRTX1719 demonstrated minimal effects on SDMA and viability in MTAP WT tumor xenografts, mouse or human hematopoietic cells. MRTX1719 demonstrated marked anti-tumor activity across a panel of xenograft models at well-tolerated doses. Early signs of clinical activity were observed including objective responses in patients with MTAP del melanoma, gallbladder adenocarcinoma, mesothelioma, non-small cell lung cancer, and MPNST from the Phase 1/2 study. Significance: PRMT5 was identified as a synthetic lethal target for MTAP del cancers, however, previous PRMT5 inhibitors do not selectively target this genotype. The differentiated binding mode of MRTX1719 leverages the elevated MTA in MTAP del cancers and represents a promising therapy for the ~10% of cancer patients with this biomarker.
Project description:The model is based on publication:
Mathematical analysis of gefitinib resistance of lung adenocarcinoma caused by MET amplification
Abstract:
Gefitinib, one of the tyrosine kinase inhibitors of epidermal growth factor receptor (EGFR), is effective for treating lung adenocarcinoma harboring EGFR mutation; but later, most cases acquire a resistance to gefitinib. One of the mechanisms conferring gefitinib resistance to lung adenocarcinoma is the amplification of the MET gene, which is observed in 5–22% of gefitinib-resistant tumors. A previous study suggested that MET amplification could cause gefitinib resistance by driving ErbB3-dependent activation of the PI3K pathway. In this study, we built a mathematical model of gefitinib resistance caused by MET amplification using lung adenocarcinoma HCC827-GR (gefitinib resistant) cells. The molecular reactions involved in gefitinib resistance consisted of dimerization and phosphorylation of three molecules, EGFR, ErbB3, and MET were described by a series of ordinary differential equations. To perform a computer simulation, we quantified each molecule on the cell surface using flow cytometry and estimated unknown parameters by dimensional analysis. Our simulation showed that the number of active ErbB3 molecules is around a hundred-fold smaller than that of active MET molecules. Limited contribution of ErbB3 in gefitinib resistance by MET amplification is also demonstrated using HCC827-GR cells in culture experiments. Our mathematical model provides a quantitative understanding of the molecular reactions underlying drug resistance.