Effects of Epothilone A in Combination with the Antidiabetic Drugs Metformin and Sitagliptin in HepG2 Human Hepatocellular Cancer Cells: Role of Transcriptional Factors NF-κB and p53

Abstract

Type 2 diabetes mellitus patients are at increased risk of many forms of malignancies, especially of the pancreas, colon and hepatocellular cancer. Unfortunately, little is known of the possible interaction between antidiabetic drugs and anticancer agents. The present study investigates the influence of metformin (MET) and sitagliptin (SITA) on the in vitro anticancer activity of the microtubule depolymerization inhibitor agent epothilone A (EpoA). Hepatocellular liver carcinoma cell line (HepG2) viability and apoptosis were determined by the MTT test and by double staining with PO-PRO-1 and 7-aminoactinomycin D, respectively, after treatment with EpoA, metformin or sitagliptin. The levels of nuclear factor NF-κB and p53 were evaluated in the presence and absence of inhibitors. While EpoA and MET inhibited HepG2 cell proliferation, SITA did not. EpoA and SITA induced higher p53 levels than MET. All tested drugs increased the level of NF-κB. Only MET enhanced the proapoptotic effect of EpoA. The EpoA+MET combination evoked the highest cytotoxic effect on HepG2 cells and led to apoptosis independent of p53, decreasing the level of NF-κB. These findings support the link between NF-κB and p53 in the modulation of apoptotic effects in HepG2 cells treated by EpoA. Our studies indicate that the combination of EpoA and MET applied in subtoxic doses has a stronger cytotoxic effect on liver cancer cells than each of the compounds alone. The therapeutic advantages of the combination of EpoA with MET may be valuable in the treatment of patients with diabetes mellitus type 2 (T2DM) and liver cancer.

Effect of sitagliptin, a DPP‐4 inhibitor, against DENA‐induced liver cancer in rats mediated via NF‐κB activation and inflammatory cytokines

“…In some in vitro studies, it has also reported as an apoptotic agent on colon and pancreatic cancer cell lines. Remarkably, sitagliptin has shown antiproliferative and apoptogenic effects against the human hepatoma HEPG2 liver cancer cell lines …”

Metformin: update on mechanisms of action on liver diseases

“…Its molecular mechanism includes activating NF-κB and increasing Bax, p53, and caspases-3, 8, and 9. Sliwinska et al found that metformin can accelerate the death of cancer cells induced by WP631 and reduce the dose of WP631, which may be related to a significant increase in the level of NF-κB in liver cancer cells (93). These authors also discovered that metformin enhanced the anti-hepatoma effect of tubulin depolymerization inhibitor epothilone A by enhancing its pro-apoptotic effect and increasing levels of NF-κB (94).…”

In vitro assays and techniques utilized in anticancer drug discovery

“…7‐Aminoactinomycin D is a fluorescent dye that can also be used to detect viable/non‐viable cells (excluded by viable cells) by fluorescence microscopy and FCM (Zembruski, Stache, Haefeli, & Weiss, (Figure ). Rogalska, Sliwinska, Kasznicki, Drzewoski, and Marczak () have used 7‐aminoactinomycin D to monitor the effects of a drug combination (epothilone A, metformin and sitagliptin) on hepatocellular cancer (Hep G2) cell viability by FCM. The dyes in SYTOX family (blue, green, orange and red), TOTO and TO‐PRO are other fluorescence dyes (Figure ), which can penetrate only into dead cells (King, ).…”