Bufalin Induces Cell Death in Human Lung Cancer Cells through Disruption of DNA Damage Response Pathways

Abstract

Bufalin is a key component of a Chinese medicine (Chan Su) and has been proved effective in killing various cancer cells. Its role in inducing DNA damage and the inhibition of the DNA damage response (DDR) has been reported, but none have studied such action in lung cancer in detail. In this study, we demonstrated bufalin-induced DNA damage and condensation in NCI-H460 cells through a comet assay and DAPI staining, respectively. Western blotting indicated that bufalin suppressed the protein levels associated with DNA damage and repair, such as a DNA dependent serine/threonine protein kinase (DNA-PK), DNA repair proteins breast cancer 1, early onset (BRCA1), 14-3-3 σ (an important checkpoint keeper of DDR), mediator of DNA damage checkpoint 1 (MDC1), O6-methylguanine-DNA methyltransferase (MGMT) and p53 (tumor suppressor protein). Bufalin could activate phosphorylated p53 in NCI-H460 cells. DNA damage in NCI-H460 cells after treatment with bufalin up-regulated its ATM and ATR genes, which encode proteins functioning as sensors in DDR, and also up-regulated the gene expression (mRNA) of BRCA1 and DNA-PK. But bufalin suppressed the gene expression (mRNA) of p53 and 14-3-3 σ, however, bufalin did not significantly affect the mRNA of MGMT. In conclusion, bufalin induced DNA damage in NCI-H460 cells and also inhibited its DNA repair and checkpoint function.

Bufalin derivative BF211 inhibits proteasome activity in human lung cancer cells in vitro by inhibiting β1 subunit expression and disrupting proteasome assembly

“…Our findings indicated that BF211 might influence multiple cellular functions, including transcription, translation and protein synthesis. Our results were consistent with previous reports demonstrating that bufalin influences transcription, translation and protein synthesis in cancer cells [7][8][9][10] . Interestingly, we found that BF211 disrupted proteasome function in the present study.…”

“…In a previous paper, we reported that BF211 exhibited stronger cytotoxic activity in cancer cells than bufalin [6] . Multiple papers have described the activities of BF and other bufadienolides in cancer cells [7][8][9][10][11][12] ; however, the effects…”

Chemical constituents and antimicrobial properties of <i>Phyllanthus amarus</i> (Schum & Thonn)

“…It is a component found in many Chinese traditional medicine. Bufalin has an antitumor effect against various malignancies such as hepatocellular and lung carcinoma (Zhang, 2014;Wu, 2014;Qiu et al, 2013).…”

Targeting Na+/K+‐translocating adenosine triphosphatase in cancer treatment

“…The cardiac glycoside bufalin has shown antiproliferative properties in NSCLC. Bufalin plays a role in the inhibition of the p38 MAPK and NF‐ κ B in NSCLC . Bufalin has also been found to play a role in overcoming the resistance of mutant EGFR, which leads to inhibition of the Akt/mTOR pathway and induction of reactive oxygen species production; in turn, this results in reactive oxygen species‐mediated mitochondrial apoptosis …”

“…Bufalin plays a role in the inhibition of the p38 MAPK and NF-jB in NSCLC. 88,89 Bufalin has also been found to play a role in overcoming the resistance of mutant EGFR, which leads to inhibition of the Akt/mTOR pathway and induction of reactive oxygen species production; in turn, this results in reactive oxygen species-mediated mitochondrial apoptosis. 54,[90][91][92] Trenti et al 57 found that ouabain induced the autophagic death of A549 and H1975 cells via JNK-dependent downregulation of the Bcl-2, but the autophagic protein beclin 1 remained unchanged.…”