L Qi1, J W Ye2, W H Xue1, X Tian1, H J Zhang3. 1. Department of Pharmacy, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China. 2. Department of Hepatobiliary and Pancreatic Surgery, the First Affiliated Hospital of Zhengzhou University, Open Laboratory of Key Disciplines of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation in Henan Province, Zhengzhou 450052, China. 3. Department of Endocrinology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China.
Abstract
Objective: To explore the effect of aspirin combined with metformin on the apoptosis of thyroid cancer TPC-1 cells and its mechanism. Methods: The proliferation and apoptosis of TPC-1 cells treated with different concentrations of aspirin and metformin were detected using cell count kit-8 (CCK-8) assay and flow cytometry, respectively. Western blot was used to detect the expressions of microtubule-associated protein light chain 3 (LC3), p62 and cysteinyl aspartate specific proteinase 3 (caspase-3) after treatment with aspirin, metformin and 3-Methyladenine (3-MA). Results: The relative cell viability of TPC-1 cells treated with 0.5, 1.0, 2.0, 4.0 mmol/L aspirin for 24 and 48 hours were (85.6±9.1)%, (79.9±8.6)%, (57.0±5.3)%, (55.7±5.4)%; (76.7±2.8)%, (75.4±6.1)%, (46.1±4.1)%, (36.3±3.2)%, respectively. The value of half maximal inhibitory concentration (IC(50)) for 24 and 48 hours were 4.297 mmol/L, 2.133 mmol/L, respectively. The apoptotic rate in the 1 mmol/L aspirin treatment group and negative control group were (29.2±8.5)%, (4.2±2.9)%, respectively (P<0.05). Moreover, treatment with metformin increased the protein expression of LC3Ⅱ/Ⅰ ratio, and decreased the expression of p62, while treatment with aspirin decreased the expression of LC3Ⅱ/Ⅰ ratio and increased the expression of p62. The relative cell viability of TPC-1 cells treated with metformin, 3-MA, an autophagy inhibitor, and 3-MA combined with metformin were (73.2±9.2)%, (95.8±3.3)%, (59.9±9.2)%, respectively. The apoptotic rates in these groups were (35.5±1.5)%, (12.3±1.4)%, (49.9±5.4)%, respectively. Compared with the metformin group, the relative cell viability in metformin combined with 3-MA group was significantly lower while the apoptotic rate was higher (P<0.05), which indicated that treatment with 3-MA enhanced the metformin-induced apoptosis of TPC-1 cells. The relative cell viability of TPC-1 cells in metformin group, aspirin group, metformin combined with aspirin group were (87.3±11.8)%, (85.7±9.6)%, (72.4±8.8)%, respectively. The apoptotic rates in these groups were (29.7±4.0)%, (30.5±6.5)%, (52.5±4.6)%, respectively. Compared with the metformin or aspirin group, the relative cell viability in metformin combined with aspirin group was significantly lower, while the apoptotic rate was higher (P<0.05), which indicated that aspirin enhanced the metformin-induced apoptosis of TPC-1 cells. Conclusions: Our findings indicate that metformin-mediated autophagy plays a protective role in metformin-induced apoptosis and proliferation inhibition. Aspirin enhances the metformin-induced apoptosis of thyroid cancer TPC-1 cells through inhibition of autophagy.
Objective: To explore the effect of aspirin combined with metformin on the apoptosis of thyroid cancer TPC-1 cells and its mechanism. Methods: The proliferation and apoptosis of TPC-1 cells treated with different concentrations of aspirin and metformin were detected using cell count kit-8 (CCK-8) assay and flow cytometry, respectively. Western blot was used to detect the expressions of microtubule-associated protein light chain 3 (LC3), p62 and cysteinyl aspartate specific proteinase 3 (caspase-3) after treatment with aspirin, metformin and 3-Methyladenine (3-MA). Results: The relative cell viability of TPC-1 cells treated with 0.5, 1.0, 2.0, 4.0 mmol/L aspirin for 24 and 48 hours were (85.6±9.1)%, (79.9±8.6)%, (57.0±5.3)%, (55.7±5.4)%; (76.7±2.8)%, (75.4±6.1)%, (46.1±4.1)%, (36.3±3.2)%, respectively. The value of half maximal inhibitory concentration (IC(50)) for 24 and 48 hours were 4.297 mmol/L, 2.133 mmol/L, respectively. The apoptotic rate in the 1 mmol/L aspirin treatment group and negative control group were (29.2±8.5)%, (4.2±2.9)%, respectively (P<0.05). Moreover, treatment with metformin increased the protein expression of LC3Ⅱ/Ⅰ ratio, and decreased the expression of p62, while treatment with aspirin decreased the expression of LC3Ⅱ/Ⅰ ratio and increased the expression of p62. The relative cell viability of TPC-1 cells treated with metformin, 3-MA, an autophagy inhibitor, and 3-MA combined with metformin were (73.2±9.2)%, (95.8±3.3)%, (59.9±9.2)%, respectively. The apoptotic rates in these groups were (35.5±1.5)%, (12.3±1.4)%, (49.9±5.4)%, respectively. Compared with the metformin group, the relative cell viability in metformin combined with 3-MA group was significantly lower while the apoptotic rate was higher (P<0.05), which indicated that treatment with 3-MA enhanced the metformin-induced apoptosis of TPC-1 cells. The relative cell viability of TPC-1 cells in metformin group, aspirin group, metformin combined with aspirin group were (87.3±11.8)%, (85.7±9.6)%, (72.4±8.8)%, respectively. The apoptotic rates in these groups were (29.7±4.0)%, (30.5±6.5)%, (52.5±4.6)%, respectively. Compared with the metformin or aspirin group, the relative cell viability in metformin combined with aspirin group was significantly lower, while the apoptotic rate was higher (P<0.05), which indicated that aspirin enhanced the metformin-induced apoptosis of TPC-1 cells. Conclusions: Our findings indicate that metformin-mediated autophagy plays a protective role in metformin-induced apoptosis and proliferation inhibition. Aspirin enhances the metformin-induced apoptosis of thyroid cancer TPC-1 cells through inhibition of autophagy.