目的:研究miRNA-200c对人胃癌耐药SGC7901/DDP细胞顺铂敏感性的影响及其机制。方法:Western blotting检测SGC7901/DDP及其亲代SGC7901细胞E-cadherin、PTEN、p-Akt及总Akt蛋白的表达;瞬时转染miRNA-200c前体(miR-NA-200c precursor,Pre-...目的:研究miRNA-200c对人胃癌耐药SGC7901/DDP细胞顺铂敏感性的影响及其机制。方法:Western blotting检测SGC7901/DDP及其亲代SGC7901细胞E-cadherin、PTEN、p-Akt及总Akt蛋白的表达;瞬时转染miRNA-200c前体(miR-NA-200c precursor,Pre-200c)提高SGC7901/DDP细胞miRNA-200c的表达,MTT法检测转染后SGC7901/DDP细胞对顺铂的敏感性,并分析p-Akt表达的改变;应用Akt通路抑制剂LY94002处理SGC7901/DDP细胞抑制Akt磷酸化,检测处理后细胞对顺铂的敏感性。结果:与SGC7901细胞相比,SGC7901/DDP细胞中p-Akt蛋白的表达量显著增高(1.02±0.09 vs 0.17±0.02,P<0.05),E-cadherin、PTEN蛋白的表达量显著降低(0.10±0.03 vs 0.47±0.06,0.18±0.06 vs 0.87±0.06;均P<0.05)。转染Pre-200c后,顺铂对SGC7901/DDP细胞的IC50显著低于对照组[(7.52±0.19)vs(12.18±0.29)mg/L,P<0.05],细胞中p-Akt蛋白的表达量也显著低于对照组(0.22±0.04 vs 0.69±0.09,P<0.05);LY94002处理后,SGC7901/DDP细胞p-Akt蛋白的表达显著抑制(0.18±0.06 vs 0.66±0.10,P<0.05),顺铂对细胞的IC50显著低于对照组[(6.80±0.28)vs(11.94±1.73)mg/L,P<0.05]。结论:SGC7901/DDP细胞的耐药可能与E-cadherin和PTEN蛋白的表达缺失及Akt通路的异常激活有关,而miRNA-200c提高该细胞对顺铂的敏感性可能是通过抑制Akt通路而发挥作用。展开更多
Background and Objective: miRNA-200c can not only inhibit the aggressiveness of cancer cells but also increase the sensitivity of cells to antitumor drugs. However, some mechanisms are still unclear. Recent researches...Background and Objective: miRNA-200c can not only inhibit the aggressiveness of cancer cells but also increase the sensitivity of cells to antitumor drugs. However, some mechanisms are still unclear. Recent researches revealed that E-cadherin is more than an inhibitor of metastasis, and it also plays important roles in reversing drug resistance. We had previously found that miRNA-200c could not only induce the expression of E-cadherin but also increase the sensitivity of gastric cancer SGC7901/DDP cells to cisplatin (DDP). This study aimed to explore the effects of miRNA-200c on biological characteristics of SGC7901/DDP cells and the roles of E-cadherin in the regulatory pathway of miRNA-200c. Methods: SGC7901/DDP cells and its parental cell line SGC7901 cells were transfected with miRNA-200c precursor (Pre-200c) and E-cadherin siRNA, respectively. Real-time RT-PCR was used to detect miRNA-200c expression after transfection with Pre-200c in SGC7901/DDP cell line. Drug sensitivities to DDP, 5-fluorouracil (5-FU), paclitaxel, and adriamycin (ADR) after transfection were tested using MTT assay. The proliferation of SGC7901/DDP cells was also detected after transfection. The protein changes of E-cadherin, Bax, and Bcl-2 after transfection were detected by Western blot. Results: The miRNA-200c expression in SGC7901/DDP cells after transfection of Pre-200c was 7.128 ± 0.159 times of that in negative control (P < 0.05). The IC50 of DDP, 5-FU, paclitaxel, and ADR in Pre-200c-transfected group were significantly lower than that in negative control group (P < 0.05). Compared to the control group, cell proliferation was significantly decreased (P < 0.05). The relative protein expressions of E-cadherin and Bax in Pre-200c-transfected group were significantly higher than those in negative control group (P < 0.05), whereas Bcl-2 was significantly lower than that in control (P < 0.05). Additionally, E-cadherin protein expression was significantly inhibited after transfected with E-cadherin siRNA in SGC7901 cells. The Bax protein expression was significantly down-regulated by E-cadherin siRNA (P < 0.05), whereas the Bcl-2 expression was significantly up-regulated (P < 0.05). Conclusion: miRNA-200c can indirectly regulate apoptosis through E-cadherin in SGC7901/DDP cells, which may be a possible mechanism of miRNA-200c in reversing drug resistance and inhibiting proliferation.展开更多
文摘目的:研究miRNA-200c对人胃癌耐药SGC7901/DDP细胞顺铂敏感性的影响及其机制。方法:Western blotting检测SGC7901/DDP及其亲代SGC7901细胞E-cadherin、PTEN、p-Akt及总Akt蛋白的表达;瞬时转染miRNA-200c前体(miR-NA-200c precursor,Pre-200c)提高SGC7901/DDP细胞miRNA-200c的表达,MTT法检测转染后SGC7901/DDP细胞对顺铂的敏感性,并分析p-Akt表达的改变;应用Akt通路抑制剂LY94002处理SGC7901/DDP细胞抑制Akt磷酸化,检测处理后细胞对顺铂的敏感性。结果:与SGC7901细胞相比,SGC7901/DDP细胞中p-Akt蛋白的表达量显著增高(1.02±0.09 vs 0.17±0.02,P<0.05),E-cadherin、PTEN蛋白的表达量显著降低(0.10±0.03 vs 0.47±0.06,0.18±0.06 vs 0.87±0.06;均P<0.05)。转染Pre-200c后,顺铂对SGC7901/DDP细胞的IC50显著低于对照组[(7.52±0.19)vs(12.18±0.29)mg/L,P<0.05],细胞中p-Akt蛋白的表达量也显著低于对照组(0.22±0.04 vs 0.69±0.09,P<0.05);LY94002处理后,SGC7901/DDP细胞p-Akt蛋白的表达显著抑制(0.18±0.06 vs 0.66±0.10,P<0.05),顺铂对细胞的IC50显著低于对照组[(6.80±0.28)vs(11.94±1.73)mg/L,P<0.05]。结论:SGC7901/DDP细胞的耐药可能与E-cadherin和PTEN蛋白的表达缺失及Akt通路的异常激活有关,而miRNA-200c提高该细胞对顺铂的敏感性可能是通过抑制Akt通路而发挥作用。
文摘Background and Objective: miRNA-200c can not only inhibit the aggressiveness of cancer cells but also increase the sensitivity of cells to antitumor drugs. However, some mechanisms are still unclear. Recent researches revealed that E-cadherin is more than an inhibitor of metastasis, and it also plays important roles in reversing drug resistance. We had previously found that miRNA-200c could not only induce the expression of E-cadherin but also increase the sensitivity of gastric cancer SGC7901/DDP cells to cisplatin (DDP). This study aimed to explore the effects of miRNA-200c on biological characteristics of SGC7901/DDP cells and the roles of E-cadherin in the regulatory pathway of miRNA-200c. Methods: SGC7901/DDP cells and its parental cell line SGC7901 cells were transfected with miRNA-200c precursor (Pre-200c) and E-cadherin siRNA, respectively. Real-time RT-PCR was used to detect miRNA-200c expression after transfection with Pre-200c in SGC7901/DDP cell line. Drug sensitivities to DDP, 5-fluorouracil (5-FU), paclitaxel, and adriamycin (ADR) after transfection were tested using MTT assay. The proliferation of SGC7901/DDP cells was also detected after transfection. The protein changes of E-cadherin, Bax, and Bcl-2 after transfection were detected by Western blot. Results: The miRNA-200c expression in SGC7901/DDP cells after transfection of Pre-200c was 7.128 ± 0.159 times of that in negative control (P < 0.05). The IC50 of DDP, 5-FU, paclitaxel, and ADR in Pre-200c-transfected group were significantly lower than that in negative control group (P < 0.05). Compared to the control group, cell proliferation was significantly decreased (P < 0.05). The relative protein expressions of E-cadherin and Bax in Pre-200c-transfected group were significantly higher than those in negative control group (P < 0.05), whereas Bcl-2 was significantly lower than that in control (P < 0.05). Additionally, E-cadherin protein expression was significantly inhibited after transfected with E-cadherin siRNA in SGC7901 cells. The Bax protein expression was significantly down-regulated by E-cadherin siRNA (P < 0.05), whereas the Bcl-2 expression was significantly up-regulated (P < 0.05). Conclusion: miRNA-200c can indirectly regulate apoptosis through E-cadherin in SGC7901/DDP cells, which may be a possible mechanism of miRNA-200c in reversing drug resistance and inhibiting proliferation.
