Identifying PIF1 as a Potential Target of Wenxia Changfu Formula in Promoting Lung Cancer Cell Apoptosis: Bioinformatics Analysis and Biological Evidence

Abstract

Lung cancer remains the leading cause of cancer-related deaths worldwide. Traditional Chinese medicine (TCM) is a valuable resource of active natural products and plays an important role in cancer treatment with the advantages of high efficiency and safety. Wenxia Changfu formula (WCF) is modified from Dahuang Fuzi decoction from Han Dynasty and has been used for treating lung cancer in China. Our previous research showed that WCF had an antitumor effect in vivo and in vitro, while the mechanism has not been well illustrated. In this study, the effect of WCF on the proliferative ability in three lung cancer cells and one noncancerous human cell line was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. WCF suppressed A549, H460, and PC-9 cell viability in a dose-dependent manner, with no inhibition of noncancerous MRC-5 cells after 48 h treatment with WCF (0–50 mg/mL). Furthermore, we screened for genes in A549 cells using four WCF-treated samples and four control samples on a gene expression profile microarray. 21 genes were significantly downregulated by WCF, which may potentially play an important role in the proliferation of A549 cells. High-content screening evaluated whether silencing the 21 genes affected A549 cell growth. The results showed that PIF1 knockdown exhibited the most potent inhibition of cell proliferation compared with the other genes. Downregulation of PIF1 increased A549 cell apoptosis and the activity of caspase 3/7. Besides, RT-PCR showed that the expression levels of PIF1 mRNA decreased significantly in A549, H460, and PC-9 cells after WCF treatment. In conclusion, the present observations indicate that WCF may inhibit lung cancer cell proliferation by promoting apoptosis via regulating the expression of PIF1.

Up-regulated PIF1 predicts poor clinical outcomes and correlates with low immune infiltrates in clear cell renal cell carcinoma

“…Previous studies suggested that the knockdown of PIF1 inhibited the growth of human NSCLC cells and promoted cell apoptosis and could serve as a potential therapeutic target for treating lung cancer. ( Yin et al, 2021 ). Meanwhile, the lower expression of PIF1 can cause cell cycle arrest in the late G (1)/early S-phase and apoptosis in human breast cancer cell lines.…”

The ethyl acetate extract of Wenxia Changfu Formula inhibits the carcinogenesis of lung adenocarcinoma by regulating PI3K-AKT signaling pathway

“…The result showed that Wenxia Changfu Formula had no significant toxic effects on mice. It is noted that Wenxia Changfu Formula could inhibit cell proliferation of lung cancer by promoting apoptosis via regulating the expression of PIF1 7 . Clinically, Ginseng has been used to treat lung adenocarcinoma 8 .…”

Tideglusib Inhibits Pif1 Helicase of Bacteroides sp. via an Irreversible and Cys-380-Dependent Mechanism

“… 24 , 25 hPfi1 has therefore been proposed as a cancer therapy target. 26 − 28 However, no small-molecule inhibitors of Pif1 helicases have been reported before.…”

“…Additionally, several studies found that hPif1 physically interacts with the proliferating cell nuclear antigen (PCNA) to promote BIR which is a conserved homologous recombination (HR) pathway for DNA double-strand break repair (DSBR). , Indeed, hPif1 is recruited to the site of DNA damage and facilitates DNA resection, specifically for the sequences prone to form G4 structures . Also, the helicase activity of hPif1 is indispensable for BIR and the normal level of crossover HR. , Furthermore, hPif1 has been proved to be required for the maintenance of replication fork progression during tumorigenesis, especially during replication stress induced by genotoxic drugs or ionizing radiation, such as chemotherapy and radiotherapy. , hPfi1 has therefore been proposed as a cancer therapy target. − However, no small-molecule inhibitors of Pif1 helicases have been reported before.…”