اثر سمیت سلولی مهار کننده γ-secretase (DAPT) در سرطان معده از طریق القای آپوپتوز و مهار رشد صورت می گیرد

عنوان انگليسی

The cytotoxicity effect of γ-secretase inhibitor (DAPT) on gastric cancer is mediated by apoptosis induction and growth inhibition

خلاصه انگلیسی

Backgrounds: Gastric cancer is one of the most common and lethal malignancies with high mortality rate in the world. Despite a recent decline in its incidence, the overall 5-year survival rate for gastric cancer patient after curative-intent resection remains around 40% in the western countries. Notch signaling pathway is activated during embryogenesis and cellular development. It plays significant role in cell fate determination and differentiation. Aberrant activation of this signaling pathway may lead to malignancies including gastric cancer. Therefore, in recent investigations, Notch was proposed as a pharmacological target for the therapy of several cancers. Notch activation requires proteolytic cleavage by gamma-secretase. γ-secretase, a multisubunit complex, is responsible for the intramembrane proteolysis of various type I transmembrane proteins such as amyloid β-precursor protein and Notch. Proteolytic action of γ-secretase in Notch activation was targeted as a therapeutically vulnerable point in this pathway. Numbers of γ-secretase inhibitors (GSIs) have been development that effectively inhibit Notch activity and can suppress cellular proliferation and induce apoptosis in several cancer cells. DAPT (N-[N-(3, 5 difluorophenyl -L-alanyl)] - Phenylglycine t-butyl ester) is a type of GSI that can efficiently block cleavage activity of γ-secretase. Methods: Human gastric carcinoma (AGS) cell lines were treated with different concentrations of DAPT. Viability of cells was measured by MTT assy. Ethidium bromide/acridine orange (EB/AO) staining was used for apoptotic cell detection. Caspase-3 activation was measured by luminescent kit and was confirmed by RT-PCR. Results: MTT assay showed the 10µm of DAPT exerted an anti-proliferative effect on gastric cancer cell line (AGS) after 72 h of incubation. Cells Morphological characteristics of DAPT-treated were determined by EB/AO staining and analyzed under a fluorescent microscope. The EB/AO staining showed an increase in apoptotic cells. In addition, we indicated that DAPT treatment of gastric cancer cells could induce apoptosis through Caspase3 activation. Moreover, results of RT-PCR showed that in DAPT treated group the expression of Caspase3 was increased in comparison with control group. Conclusion: Taken together, blocking Notch signaling lead to decrease in cellular proliferation and induce apoptosis in gastric cancer cells. Furthermore, it seems, inhibition of Notch signaling Pathway by γ-secretase inhibitor (DAPT) is expected to be a potential target of novel therapeutic strategies for gastric cancer.

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