Dapagliflozin induces apoptosis by downregulating cFILP(L) and increasing cFILP(S) instability in Caki-1 cells

Dapagliflozin is a sodium/glucose cotransporter 2 inhibitor used recently to treat patients with type 2 diabetes. A recent study has demonstrated that dapagliflozin induces apoptosis in human renal and breast tumor cells. However, to the best of our knowledge, the molecular mechanism underlying dapagliflozin-mediated apoptosis in Caki-1 human renal carcinoma cells has not been elucidated. The present study demonstrated that the dapagliflozin treatment dose-dependently increased cell death in Caki-1 cells. Dapagliflozin treatment also induced apoptosis as confirmed by FITC-conjugated Annexin V/PI staining. Additionally, treatment with dapagliflozin reduced the expression levels of anti-apoptotic proteins, cellular Fas-associated death domain-like interleukin-1-converting enzyme-inhibitory protein (cFLIP)(L) and cFLIP(S) in Caki-1 cells. Benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl-ketone inhibited dapagliflozin-induced apoptosis, implying that dapagliflozin-induced apoptosis is regulated by a caspase-dependent pathway. By contrast, N-acetylcysteine had no effect on dapagliflozin-induced apoptosis and downregulation of cFLIP(L) and cFLIP(S) expression. Furthermore, overexpression of cFLIP(L), but not cFLIP(S), partially inhibited apoptosis induced by dapagliflozin. cFLIP(L) and cFLIP(S) mRNA levels remained constant in Caki-1 cells after treatment with 0, 20, 40, 60, 80 and 100 mu M dapagliflozin. Notably, it was confirmed that cFLIP(S) protein levels were reduced due to the increased cFLIP(S) instability in dapagliflozin-treated Caki-1 cells. The present study also demonstrated that dapagliflozin had no effect on HK-2 normal human kidney cells. Taken together, the present study revealed that dapagliflozin induced apoptosis via the downregulation of cFLIP(L) and an increase in cFLIP(S) instability, suggesting that dapagliflozin may be a feasible drug candidate for the treatment of human renal cancer.