Fanconi anemia complementation group-F (FANCF) is a key factor to maintain the function of FA/BRCA, a DNA-damage response pathway. However, the functional role of FANCF in breast cancer has not been elucidated. In this study, we examined the effects and mechanisms of FANCF-RNAi on the sensitivity of breast cancer cells to mitoxantrone (MX). FANCF silencing by FANCF-shRNA blocked functions of FA/BRCA pathway through inhibition of FANCD2 mono-ubiquitination in breast cancer cell lines MCF-7 and T-47D. In addition, FANCF shRNA inhibited cell proliferation, induced apoptosis, and chromosome fragmentation in both breast cancer cells. We also found that FANCF silencing potentiated the sensitivity to MX in breast cancer cells, accompanying with an increase in intracellular MX accumulation and a decrease in BCRP expression. Furthermore, we found that the blockade of FA/BRCA pathway by FANCF-RNAi activated p38 and JNK MAPK signal pathways in response to MX treatment. BCRP expression was restored by p38 inhibitor SB203580, but not by JNK inhibitor SP600125. FANCF silencing increased JNK and p38 mediated activation of p53 in MX-treated breast cancer cells, activated the mitochondrial apoptosis pathway. Our findings indicate that FANCF shRNA potentiates the sensitivity of breast cancer cells to MX, suggesting that FANCF may be a potential target for therapeutic strategies for the treatment of breast tumors.

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In the present study, we downregulated FANCF expression by small interfering RNA (siRNA) in OVCAR ovarian cancer cells to address the effects of decreased FANCF expression on the function of the Fanconi anemia (FA)/breast cancer susceptibility gene (BRCA) pathway. Furthermore, we investigated whether this method increases the sensitivity of OVCAR3 cells to adriamycin (ADM) and the possible mechanism(s). We found that silencing of FANCF inactivated the FA/BRCA pathway by decreasing the monoubiquitination and focus formation of FANCD2 and reduced the function of the FA/BRCA pathway, resulting in the inhibition of cell proliferation, increased cell apoptosis and DNA damage in OVCAR3 cells. Moreover, we observed that silencing of FANCF enhanced the antiproliferative effect of ADM in OVCAR3 cells and increased ADM intracellular accumulation consequently sensitizing OVCAR3 cells to ADM. Furthermore, silencing of FANCF increased cell apoptosis of OVCAR3 cells which was caused by decreased mitochondrial membrane potential (MMP)-induced DNA damage, activated Jun N-terminal kinase (JNK), increased release of cytochrome c, increased expression of cleaved caspase-3 and poly(ADP-ribose) polymerase (PARP) dependent on JNK activation following treatment of ADM. Collectively, we confirm that silencing of FANCF sensitizes OVCAR3 ovarian cancer cells to ADM, suggesting that FANCF may serve as a potential target for therapeutic strategies in the treatment of ovarian cancer.

This study investigated the pharmacokinetics, pharmacodynamics, and safety of fotagliptin benzoate (fotagliptin), a dipeptidyl peptidase-4 (DPP-4) inhibitor, in Chinese patients with type 2 diabetes mellitus (T2DM). In a randomized, doubleblinded, placebo-controlled study, 10 and 4 patients with T2DM were randomized and received, respectively, once-daily oral fotagliptin (24 mg) or placebo, for 14 days. The pharmacokinetics and pharmacodynamics were assessed throughout the study, including monitoring DPP-4, glucagon-like peptide-1 (GLP-1), glycosylated hemoglobin, and fasting blood glucose. Fotagliptin was rapidly absorbed, and the median time to maximum concentration value was ∼1.5 hours. Plasma fotagliptin levels were stable after 14 days of once-daily dosage. The accumulation ratios for the area under the plasma concentration-time curve of fotagliptin, M1, and M2-1, were 1.19 ± 0.10, 1.59 ± 0.27, and 1.39 ± 0.26, respectively. The durations for DPP-4 inhibition >80% in the fotagliptin group on days 1 and 14 were 23.5 and 24.0 hours, respectively. The concentrations of GLP-1 were higher on days 1 and 14 than at the baseline. No serious complications occurred. Fotagliptin showed favorable pharmacokinetics and pharmacodynamics and was well tolerated. Treatment with fotagliptin can achieve high DPP-4 inhibition and increase plasma GLP-1. A once-per-day dosing regimen may be recommended as clinically efficacious.

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