Accession Number : ADA467641

Title :   Cannabinoid Receptors: A Novel Target for Therapy of Prostate Cancer

Descriptive Note : Annual rept., 19 Jan 2006-18 Jan 2007


Personal Author(s) : Mukhtar, Hasan ; Afaq, Farrukh ; Sarfaraz, Sami

Full Text :

Report Date : Feb 2007

Pagination or Media Count : 55

Abstract : In recent years, cannabinoids, the active components of Cannabis sativa linnaeus (marijuana) and their derivatives are drawing renewed attention because of their diverse pharmacological activities such as cell growth inhibition and tumor regression. We have shown that the expression levels of both cannabinoid receptors CB1 and CB2 are higher in human prostate cancer cells than in normal prostate epithelial cells and treatment of LNCaP cells with WIN-55,212-2 (WIN) resulted in inhibition of cell growth and induction of apoptosis. Next study was conducted to understand the mechanistic basis of these effects. Treatment of LNCaP cells with WIN resulted in (1) an arrest of the cells in the G0/G1 phase of the cell cycle; (2) an induction of p53 & p27/KIP1; (3) down-regulation of cyclins D1, D2, E, decrease in the expression of cdk -2, -4, and -6; (4) decrease in protein expression of pRb; (5) down-regulation of E2F (1-4); and (6) decrease in the protein expression of DP1 and DP2. Similar effects were also observed when androgen-independent PC3 cells were treated with WIN(5-30 micrometers). We further observed sustained up regulation of ERK1/2, and inhibition of PI3k/Akt pathways in WIN-55,212-2 treated cells. Inhibition of ERK1/2 abrogated WIN induced cell death suggesting that sustained activation of ERK1/2 leads to cell-cycle dysregulation and arrest of cells in G0/G1 phase subsequently leading to an induction of apoptosis. Further, WIN treatment of cells resulted in a dose-dependent increase in Bax/Bcl-2 ratio in such a way that favors apoptosis. The induction of apoptosis proceeded through down regulation of caspases 3, 6, 7, and 9 and cleavage of PARP. Based on these data we suggest that cannabinoid receptor agonists should be considered as novel agents for the management of prostate cancer.


Subject Categories : Medicine and Medical Research

Distribution Statement : APPROVED FOR PUBLIC RELEASE