The Fanconi anemia pathway sensitizes to DNA alkylating agents by inducing JNK-p53-dependent mitochondrial apoptosis in breast cancer cells.
The Fanconi anemia/BRCA (FA/BRCA) DNA damage repair pathway plays a pivotal role in the cellular response to DNA alkylating agents and greatly influences drug response in cancer treatment. However, the molecular mechanisms underlying the FA/BRCA pathway reversed resistance have received limited attention. In the present study, we investigated the effect of Fanconi anemia complementation group F protein (FANCF), a critical factor of the FA/BRCA pathway, on cancer cell apoptosis induced by DNA alkylating agents such as mitomycin c (MMC). We found that FANCF shRNA potentiated MMC-induced cytotoxicity and apoptosis in MCF-7 and MDA-MB-231 breast cancer cells. At a mechanistic level, FANCF shRNA downregulated the anti-apoptotic protein Bcl-2 and upregulated the pro-apoptotic protein Bax, accompanied by release of cyt-c and smac into the cytosol in MMC-treated cells. Furthermore, activation of caspase-3 and -9, other than caspase-8, cleavage of poly(ADP ribose) polymerase (PARP), and a decrease of mitochondrial membrane potential (MMP) indicated that involvement of the mitochondrial apoptotic pathway in FANCF silencing of MMC-treated breast cancer cells. A decrease in IAP family proteins XIAP and survivin were also observed following FANCF silencing in MMC-treated breast cancer cells. Notably, FANCF shRNA was able to increase p53 levels through activation of the JNK pathway in MMC-treated breast cancer cells. Furthermore, p53 inhibition using pifithrin-α abolished the induction of caspase-3 and PARP by FANCF shRNA and MMC, indicating that MMC-induced apoptosis is substantially enhanced by FANCF shRNA via p53-dependent mechanisms. To our knowledge, we provide new evidence for the potential application of FANCF as a chemosensitizer in breast cancer therapy.
Department of Pharmacology, School of Pharmaceutical Science, China Medical University, Heping Ward, Shenyang, Liaoning 110001, P.R. China.
Lin
L
Zhao
Department of Pharmacology, School of Pharmaceutical Science, China Medical University, Heping Ward, Shenyang, Liaoning 110001, P.R. China.
Yanlin
Y
Li
Department of Pharmacology, School of Pharmaceutical Science, China Medical University, Heping Ward, Shenyang, Liaoning 110001, P.R. China.
Miao
M
He
Department of Pharmacology, School of Pharmaceutical Science, China Medical University, Heping Ward, Shenyang, Liaoning 110001, P.R. China.
Zhiguo
Z
Song
Department of Pharmacology, School of Pharmaceutical Science, China Medical University, Heping Ward, Shenyang, Liaoning 110001, P.R. China.
Shu
S
Lin
Department of Pharmacology, School of Pharmaceutical Science, China Medical University, Heping Ward, Shenyang, Liaoning 110001, P.R. China.
Zhaojin
Z
Yu
Department of Pharmacology, School of Pharmaceutical Science, China Medical University, Heping Ward, Shenyang, Liaoning 110001, P.R. China.
Xuefeng
X
Bai
Institute of Pathology and Pathophysiology, China Medical University, Heping Ward, Shenyang, Liaoning 110001, P.R. China.
Enhua
E
Wang
Department of Pharmacology, School of Pharmaceutical Science, China Medical University, Heping Ward, Shenyang, Liaoning 110001, P.R. China.
Minjie
M
Wei
D000477:Alkylating Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D052219:Fanconi Anemia Complementation Group F Protein / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D061986:MCF-7 Cells; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D016685:Mitomycin / Q000494:pharmacology*; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction
D000477:Alkylating Agents; D052219:Fanconi Anemia Complementation Group F Protein; D034741:RNA, Small Interfering; D016685:Mitomycin