Bu-Fei decoction and modified Bu-Fei decoction inhibit the growth of non-small cell lung cancer, possibly via inhibition of apurinic/apyrimidinic endonuclease 1

Human apurinic/apyrimidinic endonuclease 1 (APE1) is a ubiquitous multifunctional protein, which possesses DNA repair and redox activities. High levels of APE1 are associated with chemo- and radioresistance, and poor prognosis in various types of cancer, including non-small cell lung cancer (NSCLC). Bu-Fei decoction (BFD) is a traditional Chinese herbal formula, which is believed to supplement Qi, clear away heat and nourish the lungs. BFD and modified Bu-Fei decoction (MBFD) have been used in China to treat patients with lung cancer. The present study aimed to evaluate the potential antitumor effects of BFD and MBFD on NSCLC in vitro and in vivo. In addition, the possible contribution of APE1 was examined. MTT assay was used to investigated the anti-tumor activity of BFD and MBFD on H1975 and H292 NSCLC cell lines. The DNA damage of cells in the control and the experimental groups was detected using comet assay. The in vivo anti-tumor effects of BFD and MBFD were evaluated in a NSCLC tumor nude mouse xenograft model. Polymerase chain reaction (PCR), reverse transcription-quantitative PCR (RT-qPCR) analysis and western blot analysis were applied to analyze the mRNA and protein expression levels of APE1 in H1975 and H292 cells, so as to the xenograft tumor tissues. The concentration of APE1 in mice plasma was determined using enzyme linked immunosorbent assay (ELISA). In vitro, BFD and MBFD inhibited the growth of cultured H1975 and H292 NSCLC cells. The results of a comet assay revealed that BFD and MBFD increased DNA damage. Furthermore, the expression levels of APE1 were decreased in response to BFD and MBFD at the mRNA and protein levels. In mice carrying NSCLC xenografts, BFD and MBFD inhibited tumor growth and decreased APE1 expression. In addition, in normal human lung bronchial epithelial BEAS-2B cells, the half maximal inhibitory concentrations of BFD and MBFD were much higher compared with in NSCLC cells, and they had no effect on DNA damage. These results suggested that BFD and MBFD may inhibit the growth of NSCLC, possibly by inhibiting APE1 expression.