Mycotoxin verrucarin A inhibits proliferation and induces apoptosis in prostate cancer cells by inhibiting prosurvival Akt/NF-kB/mTOR signaling
Liu Y, Gao X, Deeb D, Zhang Y, Shaw J, Valeriote FA, Gautam SC. Mycotoxin verrucarin A inhibits proliferation and induces apoptosis in prostate cancer cells by inhibiting prosurvival Akt/NF-kB/mTOR signaling. J Exp Ther Oncol. 2016 Nov;11(4):251-260.
Journal of experimental therapeutics & oncology
Trichothecenes are powerful mycotoxins that inhibit protein synthesis and induce ribotoxic stress response in mammalian cells. Verrucarin A (VC-A) is a Type D macrocyclic mycotoxin which inhibits cell proliferation and induces apoptosis in cancer cells. However, the antitumor activity of VC-A for prostate cancer cells has not been investigated. The objective of the present study was to determine the anticancer activity and its mechanism of action in hormone-responsive (LNCaP) and hormone-refractory (PC-3) carcinoma of the prostate (CaP) cell lines. VC-A strongly inhibited the proliferation and induced cell cycle arrest in G2/M phase associated with the inhibition of cell cycle regulatory proteins cyclin D, cyclin E, cyclin-dependent kinases (cdks) cdk2, cdk4, cdk6 and cdk inhibitors WAF1/21 and KIP1/27. VC-A also induced apoptosis in CaP cells as characterized by the cleavage of poly (ADP-ribose) polymerase (PARP-1), procaspases-3, -8 and -9 and the inhibition of Bcl-2 family proteins that regulate apoptosis (Bcl-2, Bcl-xL, Bax, Bak and Bad). In addition, VC-A also down-regulated the expression of prosurvival phospho-AKT (p-AKT), nuclear factor kappa B (NF-kB) (p65) and phospho-mammalian target of rapamycin (p-mTOR) signaling proteins. Taken together, these results demonstrated strong antiproliferative and apoptosis-inducing activity of verrucarin A against CaP cells through cell cycle arrest and inhibition of the prosurvival (antiapoptotic) AKT/NF-kB/mTOR signaling pathway.
Medical Subject Headings
Apoptosis; Apoptosis Regulatory Proteins; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Down-Regulation; G2 Phase Cell Cycle Checkpoints; Humans; Male; Mycotoxins; NF-kappa B; Prostate; Prostatic Neoplasms; Proto-Oncogene Proteins c-akt; Signal Transduction; TOR Serine-Threonine Kinases; Trichothecenes