Cancer Management and Research (Jun 2023)
Metformin Induces a Caspase 3-Unrelated Apoptosis in Human Colorectal Cancer Cell Lines HCT116 and SW620
Abstract
Bustanur Rosidi,1 Diana Priyatno,1 Teguh Pribadi Putra,1 Irawan Yusuf1,2 1Division of Proteomics, Mochtar Riady Institute for Nanotechnology and Medical Science Group, University of Pelita Harapan, Tangerang, Banten, Indonesia; 2Faculty of Medicine, Hasanuddin University, Makassar, IndonesiaCorrespondence: Bustanur Rosidi; Irawan Yusuf, Mochtar Riady Institute for Nanotechnology and Medical Science Group, University of Pelita Harapan, Jalan Boulevard Jenderal Sudirman 1688, Lippo Karawaci, Tangerang, Banten, 15811, Indonesia, Tel +62 21-54210123, Email [email protected]; [email protected]: To study the effects of metformin on the proliferation and growth of human colorectal cancer cell lines HCT116 and SW620.Materials and Methods: The antiproliferative effect of metformin was assayed using an MTS reagent and its ability to inhibit colony formation was demonstrated using a clonogenic assay. Flow cytometry using YO-PRO-1/PI was performed to examine the effects of metformin on apoptosis and cell death of HCT116 and SW620. Caspase 3 activities were measured in caspase-3 activity tests using a caspase-3 activity kit. Furthermore, Western blots were performed with anti-PARP1, anti-caspase 3, and anti-cleaved caspase 3 to confirm whether caspase activation was present or not.Results: Both MTS proliferation assays and clonogenic assays showed that metformin inhibited the proliferation and growth of HCT116 and SW620 cells in a concentration-dependent manner. Flow cytometric analysis identified early apoptosis and metformin-induced cell death in both cell lines. However, caspase 3 activity could not be detected. Cleavage of both PARP1 and pro-caspase 3 was not observed in the Western blot, confirming the absence of caspase 3 activations.Conclusion: This present study suggests a caspase 3-unrelated apoptosis mechanism of metformin-induced cell death in human colorectal cancer cell lines HCT116 and SW620.Keywords: metformin, colorectal cancer, PARP1, anti-proliferative, apoptosis
