Fenofibrate potentiates chemosensitivity to human breast cancer cells by modulating apoptosis via AKT/NF-κB pathway

Abstract

Jianguo Sun,1,2,* Zhibao Zheng,1,* Qi Chen,2 Yin Pan,1 Mingming Quan,1 Yuechu Dai1 1Department of Surgical Oncology, Taizhou Central Hospital (Taizhou University Hospital), Taizhou, Zhejiang, People’s Republic of China; 2Precision Medicine Center, Taizhou Central Hospital (Taizhou University Hospital), Taizhou, Zhejiang, People’s Republic of China *These authors contributed equally to this work Background: Cumulatively, evidences revealed that fenofibrate used in the therapy of hyperlipidemia and hypercholesterolemia has anti-cancer effect in multiple cancer types. However, its function and underlying mechanism of chemosensitization in breast cancer remain poorly understood. Materials and methods: The cytotoxicity of fenofibrate and anti-cancer drugs in breast cancer cells was determined by MTT. Apoptosis and mitochondrial membrane potential were measured using flow cytometry. Caspases and PARP cleavage, the Bcl-2 family members’ protein expression, as well as the activation of AKT and NF-κB signaling pathways were evaluated using Western blot assay. Real-time PCR was used to determine the mRNA expression of Bcl-2 family members. Results: Our data indicated that fenofibrate suppressed SKBR3 and MDA-MB-231 cell growth in a dose-dependent manner, in the same way as paclitaxel, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), ABT-737, and doxorubicin. Subtoxic levels of fenofibrate significantly augmented paclitaxel, TRAIL, ABT-737, and doxorubicin-induced apoptosis in both these two cell lines. Fenofibrate-promoted chemosensitivity is predominantly mediated by caspase-9 and caspase-3 activation and mitochondrial outer membrane permeabilization. Meanwhile, chemosensitivity promoted by fenofibrate also increased the expression of Bax and Bok and decreased the expression of Mcl-1 and Bcl-xl. Mechanistically, fenofibrate effectively reduced the phosphorylation levels of AKT and NF-κB. In addition, imiquimod, an NF-κB activator, could reverse fenofibrate-induced susceptibility to ABT-737-triggered apoptosis. Conclusion: The present study provided the evidence of the underlying mechanisms on chemosensitization of fenofibrate by inducing the apoptosis of breast cancer in an AKT/NF-κB-dependent manner and implicated the potential application of fenofibrate in potentiating chemosensitivity in breast cancer therapy. Keywords: human breast cancer, fenofibrate, chemosensitization, AKT, NF-κB

Keywords

• human breast cancer
• Fenofibrate
• chemosensitization
• AKT
• NF-κB