hes1-protein--human and Endometrial-Neoplasms

Patients with poorly differentiated endometrial cancer show poor prognosis, and effective molecular target-based therapies are needed. Endometrial cancer cells proliferate depending on the activation of HES1 (hairy and enhancer of split-1), which is induced by several pathways, such as the Notch and fibroblast growth factor receptor (FGFR) signaling pathways. In addition, aberrant, ligand-free activation of the FGFR signaling pathway resulting from mutations in FGFR2 was also reported in endometrial cancer. However, a clinical trial showed that there was no difference in the effectiveness of FGFR inhibitors between patients with and without the FGFR2 mutation, suggesting a presence of another signaling pathway for the FGFR activation. Here, we investigated the signaling pathway regulating the expression of HES1 and proliferation of poorly and well-differentiated endometrial cancer cell lines Ishikawa and HEC-50B, respectively. Whereas Ishikawa cells proliferated and expressed HES1 in a Notch signaling-dependent manner, Notch signaling was not involved in HES1 and proliferation of HEC-50B cells. The FGFR inhibitor, NVP-BGJ398, decreased HES1 expression and proliferation of HEC-50B cells; however, HEC50B cells had no mutations in the FGFR2 gene. Instead, HEC-50B cells highly expressed ligands for FGFR2, suggesting that FGFR2 is activated by an autocrine manner, not by ligand-free activation. This autocrine pathway activated Akt downstream of FGFR for cell proliferation. Our findings suggest the usefulness of HES1 as a marker for the proliferation signaling and that FGFR inhibitor may be effective for poorly differentiated endometrial cancers that harbor wild-type FGFR.

Topics: Autocrine Communication; Cell Line, Tumor; Cell Proliferation; Endometrial Neoplasms; Female; Gene Expression; Humans; Molecular Targeted Therapy; Receptor, Fibroblast Growth Factor, Type 2; Receptors, Fibroblast Growth Factor; Receptors, Notch; Signal Transduction; Transcription Factor HES-1

The long non-coding RNA MEG3 has shown functional role as a tumor suppressor in many cancer types, excluding endometrial carcinoma (EC). Thus, this study tried to reveal the MEG3 dysregulation in EC samples and potential functional mechanism due to its regulation on Notch signaling pathway.. The expression profiles of MEG3 and two Notch signaling molecules, Notch1 and Hes1, were detected in both EC tissues and cell lines through real time PCR and western blot analysis. Lentiviral vector carrying whole MEG3 transcript or shRNA targeting MEG3 (shMEG3) was transfected for MEG3 dysfunction studies, and cell proliferation was analyzed through MTT and colony-formation assays. Xenograft models were also established by subcutaneous implantation and tumor growth was compared under MEG3 dysregulation.. Significant downregulation of MEG3 was observed in EC samples compared to control, while the protein levels of Notch1 and Hes1 were both upregulated. Cell proliferation was obviously inhibited by MEG3 overexpression, while opposite improved result was obtained in MEG3 knockout cells. Interestingly, MEG3-induced changes could be reversed by Notch1 regulators. Moreover, MEG3 overexpressing tumors showed strongly repressed growth in vivo, along with Notch signaling inhibition.. Downregulated MEG3 exhibited an anti-proliferative role in EC by repressing Notch signaling pathway.

Topics: Animals; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Endometrial Neoplasms; Female; Gene Expression Regulation, Neoplastic; Gene Silencing; Humans; Male; Mice, Nude; Receptor, Notch1; RNA, Long Noncoding; Signal Transduction; Transcription Factor HES-1; Up-Regulation; Xenograft Model Antitumor Assays

Endometrial cancer is one of the most common gynecological malignancies in Japan, where the disease shows an increasing morbidity. However, surgical therapy remains the treatment of choice for endometrial cancers that tend to be insensitive to radiation therapy and chemotherapy. Therefore, novel therapeutic strategies are required. The Notch signaling pathway regulates embryogenesis and cellular development, but deregulated Notch signaling may contribute to tumorigenesis in several cancers. Moreover, γ-secretase inhibitors have been shown to be potent inhibitors of the Notch signaling pathway; they suppress cellular proliferation and induce apoptosis in several cancer cells. In the present study, we investigated the effect of N-[N-(3, 5-difluorophenacetyl-L-alanyl)]-S-phenylglycine t-butyl ester (DAPT, γ-secretase inhibitor) on the cell proliferation and apoptosis in Ishikawa endometrial cancer cells. Real-time PCR detected mRNA derived from NOTCH1 and HES1, which are target genes of the Notch signaling pathway, in Ishikawa endometrial cancer cells. After blocking Notch signaling, cellular proliferation decreased, accompanied by increased expression of p21 mRNA and decreased expression of the cyclin A protein. Furthermore, blockade of Notch signaling induced apoptosis. These results suggest that the Notch signaling pathway may be involved in cell proliferation through cell cycle regulation and apoptosis in Ishikawa endometrial cancer cells. Inhibition of the Notch signaling pathway by γ-secretase inhibitors is expected to be a potential target of novel therapeutic strategies for endometrial cancer.

Topics: Amyloid Precursor Protein Secretases; Apoptosis; Basic Helix-Loop-Helix Transcription Factors; Cell Line, Tumor; Cell Proliferation; Dipeptides; Endometrial Neoplasms; Female; Gene Expression Regulation, Neoplastic; Homeodomain Proteins; Humans; Receptor, Notch1; RNA, Messenger; Signal Transduction; Transcription Factor HES-1

The RNA-binding protein Musashi-1 has been proposed to maintain stem cell function during development and regenerative processes as a modulator of the Notch-1 signaling pathway. Musashi-1 expression is upregulated in endometrial carcinoma, however, its pathogenetic role in this tumor entity is unknown. Here we investigate the functional impact and mode of action of Musashi-1 on endometrial carcinoma cell behaviour in vitro. Aldehyde dehydrogenase-1 activity and side population (SP) measurement by Hoechst dye exclusion revealed that the Ishikawa endometrial carcinoma cell line contains a pool of putative cancer stem cells. Musashi-1 expression is 20.8-fold upregulated in SP+ compared to SP- and equally distributed between ALDH+ and ALDH- cell pools. siRNA-mediated knockdown of Musashi-1 mRNA expression lead to an altered expression of the signaling receptor Notch-1 and its downstream targets, the transcription factor Hes-1 and the cell cycle regulators p21(WAF1/CIP1) and cyclin B1, as determined by Western blotting and quantitative real-time PCR. Flow cytometric and ELISA analyses revealed that Musashi-1-mediated modulation of these factors exerted an antiproliferative effect on the cell cycle, and increased apoptosis in endometrial carcinoma cells. We conclude that Ishikawa cells contain a subpopulation of cells with stem cell-like properties. Musashi-1 modulates endometrial carcinoma cell cycle progression and apoptosis via the stemness-related factors Notch-1, Hes-1 and p21(WAF1/CIP1) , thus emerging as a novel future target for endometrial carcinoma therapy.

Topics: Adult Stem Cells; Apoptosis; Basic Helix-Loop-Helix Transcription Factors; Cell Cycle; Cell Division; Cyclin-Dependent Kinase Inhibitor p21; Endometrial Neoplasms; Female; Gene Expression Regulation, Neoplastic; Homeodomain Proteins; Humans; Nerve Tissue Proteins; Receptor, Notch1; RNA-Binding Proteins; RNA, Small Interfering; Transcription Factor HES-1