On 013100, an elF4E inhibitor, exhibits potent anti-cancer activity in various preclinical cancer models

Introduction: Eukaryotic translation initiation factor 4E (eIF4E) is a master regulator that controls translation of mRNA in mammalian cells. eIF4E is a proto-oncogene that promotes translation of several genes essential for cellular proliferation (Cyclin D1, c-Myc, mTOR), survival (Akt, survivin), angiogenesis (VEGF), and metastasis (MMP9). Over-expression of eIF4E has been observed in almost all major groups of cancers and has been shown to induce increased expression of Cyclin D1 and c-Myc. ON 013100 is a novel investigational anti-cancer compound. ON 013100 binds and inhibits the activity of eIF4E. The overall objective of this study was to investigate the anticancer activity of ON 013100 against various breast cancers and Mantle Cell Lymphoma (MCL) cell lines. In addition, we analyzed the expression of markers associated with eIF4E (Cyclin Dl and c-Myc) and apoptosis (P53, Cleaved Caspase-3 and Cleaved PARP).;Methods: The effect of ON 013100 on the viability of the different cancer cell lines was assessed using cell viability (MIT) assay. The change in the expression of Cyclin D1, c-Myc and the apoptotic markers, after treatment with ON 013100, was evaluated using western blot analysis. The change in the protein expression of c-Myc and Cyclin D1 was examined quantitatively using ELISA. The effect of ON 013100 on the survival of the breast and MCL cell lines was investigated using cell survival assay and washout experiment respectively. Late stage apoptosis was investigated using DNA fragmentation Assay. Cell cycle analysis was performed to check the effect of ON 013100 on the progression of cell cycle analysis.;Results: ON 013100 inhibited the proliferation of MCL (JeKo-1 and Mino) and breast (MCF7 and MDA-MB-231) cancer cell lines at nanomolar concentrations (ON 013100: I50 = 4.5nM -- 12.3nM). The survival of the breast and MCL cells was significantly inhibited by ON 013100. Western blot analysis indicated that ON 013100 significantly reduced the expression of Cyclin D1 and c-Myc proteins. This result was supported by ELISA. The expression of pro-apoptotic proteins (P53, Cleaved Caspase-3 and Cleaved PARP) was enhanced by treatment of the cells with ON 013100. The treatment with ON 013100 resulted in fragmentation of DNA indicating late stage apoptosis. Furthermore, treatment of JeKo-1 cells with ON 013100 increased the amount of cells in the sub-G1/GO phase of the cell cycle which is indicative of cell death. ON 013100 resulted in the G1/S cell arrest of MCF 7 cells.;Conclusion: The results suggest that ON 013100 has a potent anti-cancer activity against various in vitro cancer models. It is also confirmed that ON 013100 hinders the growth of cancer cells by decreasing expression of the downstream markers of eIF4E (c-Myc and Cyclin D1). The results also indicated that ON 013100 causes programmed cell death by increasing the expression of pro-apoptotic markers (P53, Cleaved Caspase-3 and Cleaved PARP) and by the increasing the cells in the GO phase of the cell cycle. On the whole, the results indicate the potential of ON 013100 as a target of eIF4E for MCL and breast cancer and the possibility of developing a promising anti-cancer clinical agent.