Department of Biology Georgia State University, Atlanta, GA-30303.
Sweet potato (Ipomoea batatas)leaves, or greens, extensively consumed as a vegetable in Africa and Asia, are an excellent source ofdietary polyphenols such as anthocyanins and phenolic acids. Here we show that sweet potato greens extract (SPGE) has the maximum polyphenol content compared to several commercial vegetables including spinach. The polyphenol-rich SPGE exerts significant antiproliferative activity in a panel of prostate cancer cell lines while sparing normal prostate epithelial cells. Mechanistically, SPGE perturbed cell-cycle progression, reduced clonogenic survival, modulated cell-cycle and apoptosis regulatory molecules, and induced apoptosis in human prostate cancer PC-3 cells both in vitro and in vivo. SPGE-induced apoptosis has a mitochondrially-mediatedcomponent, which was attenuated by pretreatmentwith cyclosporin A. We also observed alterations of apoptosisregulatorymolecules such as inactivation of Bcl2, upregulation of BAX, cytochrome crelease, and activation of downstream apoptotic signaling. SPGE caused DNA degradation as evident by terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling (TUNEL) staining of increased concentration of 3'-DNA ends.Furthermore, apoptotic induction was caspase-dependentas shown by cleavage of caspase substrate, poly(ADP)ribosepolymerase.Oral administration of 400 mg/kg SPGE remarkably inhibited growth and progression of prostate tumor xenografts by ∼69% in nude mice, as shown by tumor volume measurements and non-invasive real-time bioluminescent imaging. Most importantly, SPGE did not cause any detectable toxicity to rapidly dividing normal tissues such as gut and bone-marrow. This is the first report to demonstrate the in vitro and in vivo anticancer activity of sweet potato greens in prostate cancer.
Written by:
Karna P, Gundala SR, Gupta MV, Shamsi SA, Pace RD, Yates C, Narayan S, Aneja R. Are you the author?
Reference: Carcinogenesis. 2011 Sep 26. Epub ahead of print.
doi: 10.1093/carcin/bgr215
PubMed Abstract
PMID: 21948980
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