Key points are not available for this paper at this time.
We have recently 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 (a mixed CB1/CB2 agonist) resulted in inhibition of cell growth and induction of apoptosis (Sarfaraz, S., Afaq, F., Adhami, V. M., and Mukhtar, H. (2005) Cancer Res. 65, 1635-1641). This study was conducted to understand the mechanistic basis of these effects. Treatment of LNCaP cells with WIN-55,212-2 (1-10 μm; 24 h) resulted in: (i) an arrest of the cells in the G0/G1 phase of the cell cycle; (ii) an induction of p53 and p27/KIP1; (iii) down-regulation of cyclins D1, D2, E; (iii) decrease in the expression of cdk-2, -4, and -6; (iv) decrease in protein expression of pRb; (v) down-regulation of E2F (1-4); and (vi) decrease in the protein expression of DP1 and DP2. Similar effects were also observed when androgen-independent PC3 cells were treated with WIN-55,212-2 (5-30 μm). 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-55,212-2-indued 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-55,212-2 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 poly (ADP-ribose) polymerases. Based on these data we suggest that cannabinoid receptor agonists should be considered as novel agents for the management of prostate cancer. We have recently 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 (a mixed CB1/CB2 agonist) resulted in inhibition of cell growth and induction of apoptosis (Sarfaraz, S., Afaq, F., Adhami, V. M., and Mukhtar, H. (2005) Cancer Res. 65, 1635-1641). This study was conducted to understand the mechanistic basis of these effects. Treatment of LNCaP cells with WIN-55,212-2 (1-10 μm; 24 h) resulted in: (i) an arrest of the cells in the G0/G1 phase of the cell cycle; (ii) an induction of p53 and p27/KIP1; (iii) down-regulation of cyclins D1, D2, E; (iii) decrease in the expression of cdk-2, -4, and -6; (iv) decrease in protein expression of pRb; (v) down-regulation of E2F (1-4); and (vi) decrease in the protein expression of DP1 and DP2. Similar effects were also observed when androgen-independent PC3 cells were treated with WIN-55,212-2 (5-30 μm). 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-55,212-2-indued 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-55,212-2 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 poly (ADP-ribose) polymerases. Based on these data we suggest that cannabinoid receptor agonists should be considered as novel agents for the management of prostate cancer. Prostate cancer (CaP) 2The abbreviations used are: CaP, prostate cancer; PI3K, phosphatidylinositol 3-kinase; PBS, phosphate-buffered saline; ERK, extracellular signal-regulated kinase; Rb, retinoblastoma. ranks as the most common noncutaneous malignancy and the second leading cause of cancer-related deaths in American males, with similar trends in many Western countries. According to an estimate of the American Cancer Society, a total of 234,460 men will be diagnosed with CaP in the United States in the year 2006 and 27,350 CaP-related deaths are predicted (1Jemal A. Siegel R.W. Ward E. Murray T. Xu J. Smigal C. Thun M.J. CA Cancer J. Clin. 2006; 56: 106-130Crossref PubMed Scopus (5532) Google Scholar). The major cause of mortality from this disease is metastasis of hormone refractory cancer cells that fail to respond to hormone ablation therapy (2Denmeade S.R. Lin X.S. Isaacs J.T. Prostate. 1996; 28: 251-265Crossref PubMed Scopus (393) Google Scholar, 3Tang D.G. Porter A.T. Prostate. 1997; 32: 284-293Crossref PubMed Scopus (183) Google Scholar). Because surgery and current treatment options have proven to be inadequate in treating and controlling CaP, the search for novel targets and mechanism-based agents for prevention and treatment of this disease has become a priority. 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, anti-inflammatory effects, and tumor regression (4Galve-Roperh I. Sanchez C. Cortes M.L. Gomez del Pulgar T. Izquierdo M. Guzman M. Nat. Med. 2000; 6: 313-319Crossref PubMed Scopus (574) Google Scholar, 5Bifulco M. Laezza C. Portella G. Vitale M. Orlando P. De Petrocellis L. Di Marzo V. FASEB J. 2001; 15: 2745-2747Crossref PubMed Scopus (123) Google Scholar, 6Sanchez C. de Ceballos M.L. del Pulgar T.G. Rueda D. Corbacho C. Velasco G. Galve-Roperh I. Huffman J.W. Ramon Y. Cajal S. Guzman M. Cancer Res. 2001; 61: 5784-5789PubMed Google Scholar, 7Casanova M.L. Blazquez C. Martinez-Palacio J. Villanueva C. Fernandez-Acenero M.J. Huffman J.W. Jorcano J.L. Guzman M. J. Clin. Investig. 2003; 111: 43-50Crossref PubMed Scopus (356) Google Scholar, 8Guzman M. Nat. Rev. Cancer. 2003; 3: 745-755Crossref PubMed Scopus (572) Google Scholar, 9Klein T.W. Nat. Rev. Immunol. 2005; 5: 400-411Crossref PubMed Scopus (589) Google Scholar). Further interest in cannabinoid research came from the discovery of the cannabinoid system and the cloning of specific cannabinoid receptors (10Guzman M. Sanchez C. Galve-Roperh I. J. Mol. Med. 2001; 78: 613-625Crossref PubMed Scopus (200) Google Scholar). Two cannabinoid receptors have been identified: the “central” CB1 and the “peripheral” CB2 receptor. In a recent study, we have shown that WIN 55,212-2 (Fig. 1) a mixed CB1/CB2 receptor agonist imparts cell growth inhibitory effects in LNCaP cells via an induction of apoptosis. An important observation of this study was that WIN 55,212-2 treatment did not result in apoptosis of the normal prostate epithelial cell at similar doses (11Sarfaraz S. Afaq F. Adhami V.M. Mukhtar H. Cancer Res. 2005; 65: 1635-1641Crossref PubMed Scopus (203) Google Scholar). Here, we show that treatment of human prostate cancer LNCaP cells with cannabinoid receptor agonist WIN-55,212-2 resulted in an arrest of the cells in the G0/G1 phase of the cell cycle, and this arrest was associated with a sustained activation of ERK1/2, induction of p27/KIP1, and inhibition of cyclin D1. Blocking of both cannabinoid receptors CB1 and CB2 by their specific antagonist resulted in inhibition of ERK1/2 activation. Inhibition of ERK1/2 signaling by the ERK1/2 inhibitor PD98059 and its specific siRNA abrogated these effects. Materials—R-(+)-WIN 55,212-2 (2,3 dihydro-5-methyl-3-(morpholinylmethyl) pyrollo (1,2,3 de)-1,4-benzoxazinyl]-1-napthalenymethanone, C27H26N2O3.CH3SO3H was purchased from Sigma. CB1 receptor antagonist SR141716 (SR1) and CB2 receptor antagonist SR144528 (SR2) were procured from Dr. Herbert H. Seltzman (NIDA, National Institutes of Health, Division of Neuroscience and Behavioral Research, through RTI International, Research Triangle Park, NC). ERK1/2 inhibitor PD98059 was purchased from Tocris Biosciences (Ellisville, MO). Dulbecco's modified Eagle's medium and fetal bovine serum were procured from Invitrogen. Antibiotics (penicillin and streptomycin) used were obtained from Cellgro Mediatech, Inc. (Herndon, VA). The mono- and polyclonal antibodies (p53, cdk2, -4, and -6, KIP1/p27, E2F-3, and DP-2) were obtained from Santa Cruz Biotechnology Inc. The human reactive monoclonal and polyclonal antibodies (cyclins D1, D2, E, pRb, E2F-1, E2F-2, E2F-4, and DP-1) were obtained from Labvision (Fremont, CA). Monoclonal and polyclonal antibodies for anti-PARP, Bcl-2 Bax were purchased from Upstate Biotechnology (Lake Placid, NY). Anti-PARP and was purchased from Upstate Biotechnology and was purchased from was purchased from and was obtained from was the protein obtained from and PC3 cells obtained from were in Dulbecco's modified Eagle's medium with fetal bovine serum and and PC3 cells were in with fetal bovine serum and The cells were cell at and in a Treatment of in was used for the treatment of cells. The of used was for dose-dependent LNCaP cells were treated with WIN-55,212-2 at for 24 in cell PC3 cells were treated with WIN-55,212-2 at and for 24 in cell cells were treated with the of CB1 and CB2 receptor in WIN-55,212-2 ERK1/2 activation cells were with SR141716 and SR144528 and in the second cells were with both the for by with WIN-55,212-2 for 24 study the of ERK1/2 in cannabinoid receptor cell growth inhibition, cells were with ERK1/2 inhibitor PD98059 for by with WIN-55,212-2 for 24 cells were at of cells in and treated with WIN-55,212-2 (1-10 for 24 The cells were and in the The cells were by and the cell was in phosphate-buffered in was to a of cell and the of cells and were a of and by cells were at a of cells in and were treated with WIN-55,212-2 for 24 The cells were with PBS, and for with and by of an apoptosis obtained from as the The cells were a at the in the of were for cell cycle and for of apoptosis. of by The cells were in cell treated with WIN-55,212-2 for 24 with at and were in at for were with normal serum in for and were with were with the cells were for with and with were the obtained from were with a to an at the in the of of by ERK1/2 and siRNA were purchased from LNCaP cells were with and siRNA the specific for LNCaP from were in a from the of was mixed with cells and were to the with the and was with an were the and were cells were for the medium was with cells were treated with WIN-55,212-2 for 24 and protein were of we observed with this of and Western treatment of cells with the medium was and the cells were with The cells were in with inhibitor for The cells were and the was in a and through a to the cell The was by at for at and the cell and was used on the of at for at a Western protein was and a The on were by in in for at with monoclonal in for to at by with and by and obtained from Biosciences of the in Western were were a to of were considered WIN-55,212-2 have shown that treatment of LNCaP cells with WIN-55,212-2 (1-10 for 24 the cell and to induction of apoptosis (11Sarfaraz S. Afaq F. Adhami V.M. Mukhtar H. Cancer Res. 2005; 65: 1635-1641Crossref PubMed Scopus (203) Google Scholar). have shown that the induction of apoptosis be cell PubMed Scopus Google Scholar, Cancer Res. 1997; PubMed Google Scholar, Rev. PubMed Scopus Google Scholar, C. J. Cancer 2000; Google Scholar, 2003; PubMed Scopus Google Scholar). in the of we the that apoptosis of LNCaP cells is via cell cycle We cell cycle to the of WIN-55,212-2 treatment on the of cells in the cell shown in with treatment resulted in a dose-dependent of cells in phase of the cell cycle and cells in phase at and This observation is important because the of human have that cell cycle are in most common Cancer Rev. PubMed Scopus Google Scholar, M. 2000; PubMed Scopus Google Scholar). with this in recent years, inhibition of the cell cycle has been as a for the management of cancer J. 2000; Google Scholar, T. H. T. Med. 2000; Scopus Google Scholar). via an of and Inhibition in D1, D2, E, and and that WIN-55,212-2 treatment of cells resulted in a cell cycle arrest and we the of WIN-55,212-2 on cell cycle in phase of the cell have shown a of in apoptosis and cell cycle through phase E. M. Cancer Rev. PubMed Scopus Google Scholar, J. Mol. PubMed Scopus (572) Google Scholar, D. V. C. M. D. J. PubMed Scopus Google Scholar). We observed a induction of by WIN-55,212-2 at (Fig. data and in the protein expression of at and of we also the of WIN-55,212-2 treatment on the protein expression of the cyclins and are to be by WIN-55,212-2 treatment of the cells resulted in a dose-dependent decrease in protein expression of cyclin D1, cyclin D2, and cyclin (Fig. as as cdk2, and (Fig. data of cyclins a decrease in the expression of cyclin cyclin and cyclin at and of (Fig. data of also a decrease in the expression of and at similar doses of In the of we the of WIN-55,212-2 on p27/KIP1, cyclin and in cell were treated with doses of WIN-55,212-2 and we an induction in and down-regulation in the protein expression of cyclin and at doses of (Fig. WIN-55,212-2 of and of has been shown to be associated with a decrease in the expression of tumor protein a of the phase in the cell cycle G. J. L. J. 1997; PubMed Scopus Google Scholar, A. P. 2005; PubMed Scopus (356) Google Scholar). we the of WIN-55,212-2 on protein expression of data that WIN-55,212-2 treatment of cells resulted in a decrease in the protein expression of of and inhibition at and of WIN-55,212-2 (Fig. Because cell cycle by to and the E2F we the protein expression of E2F shown in WIN-55,212-2 treatment of cells resulted in a dose-dependent decrease in E2F data an inhibition in and and and and and at a of and Because the of E2F is to be on its with of of we also the of WIN-55,212-2 treatment on both of and and data a decrease in the protein expression of and and and at and of WIN-55,212-2 (Fig. In the of we the of WIN-55,212-2 on E2F of and its and in cell were treated with doses of WIN-55,212-2 and we a decrease in the protein expression of E2F and at doses (Fig. of and Inhibition of to through has been that with cannabinoids leads to the activation of ERK1/2 signaling and inhibition del Pulgar T. Velasco G. Sanchez C. A. Guzman M. J. PubMed Scopus Google Scholar, I. Sanchez C. Cortes M.L. Gomez del Pulgar T. Izquierdo M. Guzman M. Nat. Med. 2000; 6: 313-319Crossref PubMed Scopus (574) Google Scholar). This sustained ERK1/2 activation cell cycle arrest M. Nat. Rev. Cancer. 2003; 3: 745-755Crossref PubMed Scopus (572) Google Scholar). We observed a and sustained activation of ERK1/2 and inhibition of and when LNCaP cell were treated with WIN-55,212-2 at a of (Fig. that ERK1/2 activation is cannabinoid cells were with SR141716 and SR144528 for by treatment with in show that was activation of ERK1/2 when treated with the WIN-55,212-2 treatment resulted in activation of antagonist were with was a decrease in the protein expression of ERK1/2 and a increase in the protein expression of as with the treatment WIN-55,212-2 (Fig. data suggest that sustained ERK1/2 activation and apoptosis is through cannabinoid of ERK1/2 to Inhibition with the of and the of ERK1/2 in cannabinoid cell growth inhibition and LNCaP cells were with ERK1/2 inhibitor PD98059 for This treatment resulted in in the of the cells. WIN-55,212-2 treatment resulted in in LNCaP cells, as cells and from the of the of LNCaP cells with PD98059 these (Fig. WIN-55,212-2 treatment of cells in cell cycle cell cycle arrest is via activation of ERK1/2, we cell cycle shown in of ERK1/2 activation by its inhibitor PD98059 resulted in a decrease in the of cells in the phase of cell cycle when with WIN-55,212-2 treatment cell cycle dysregulation leads to induction of we the of apoptosis by shown in WIN-55,212-2 treatment of LNCaP cells at a of resulted in of cells. was when WIN-55,212-2 was with PD98059 μm). We PD98059 the activation of ERK1/2 by WIN-55,212-2 treatment and we that ERK1/2 protein expression was when WIN-55,212-2 was in with PD98059 (Fig. We the of PD98059 on (Fig. a cell cycle in phase of the cell cycle, and cyclin because of its in cell WIN-55,212-2 treatment the protein expression of this increase in expression was when WIN-55,212-2 was in with WIN-55,212-2 treatment the expression of cyclin D1, and this was when WIN-55,212-2 was with PD98059 (Fig. We also observed a decrease in the protein expression of a protein when the cells were treated with WIN-55,212-2 at μm; this was to when WIN-55,212-2 was with ERK1/2 inhibitor (Fig. of treatment of WIN-55,212-2 and ERK1/2 of LNCaP cell cycle in LNCaP cells. cycle was by as The cells were a and the of cells in and were The data shown are from a of apoptosis by are considered as and their is from with similar protein expression of p27/KIP1, cyclin D1, and Bcl-2 in LNCaP cells. the cells were treated with of WIN-55,212-2 and ERK1/2 inhibitor cell were for The of the to The data shown are from a with similar with with E, of ERK1/2 activation of ERK1/2 and and down-regulation of cyclin and LNCaP cells with siRNA for and were treated with WIN-55,212-2 for 24 were by antibodies ERK1/2 cyclin D1, and The of the to The data shown are from a with similar with with further the of ERK1/2 in cell cycle arrest leading to we ERK1/2 by We observed that WIN-55,212-2 did not ERK1/2 activation and when ERK1/2 was (Fig. protein expression of cyclin and Bcl-2 by WIN-55,212-2 was to be when ERK1/2 was WIN-55,212-2 via the data suggest that WIN-55,212-2 growth inhibition via cell cycle arrest in phase of the cell cycle by apoptosis. Because p53 is of the major of expression of this tumor cells to apoptosis in to We observed a up-regulation in the protein expression of p53 when cells were treated with WIN-55,212-2 (Fig. apoptosis from pathways that and signaling and In this p53 the Bcl-2 Bax and the protein Because Bax and Bcl-2 a in we the of WIN-55,212-2 treatment of LNCaP cells on protein levels of Bax and The Western a increase in the protein expression of Bax at and of WIN-55,212-2 (Fig. In the protein expression of Bcl-2 was by WIN-55,212-2 treatment in a dose-dependent (Fig. dose-dependent in the ratio of Bax to Bcl-2 was observed WIN-55,212-2 treatment the induction of (Fig. data an increase in protein expression of Bax by and with decrease in Bcl-2 protein expression by and at a of and decrease in Bcl-2 expression was associated with an increase in to and at the doses of WIN-55,212-2 (Fig. in Bax/Bcl-2 is to we the of caspases death of LNCaP cells. shown by the WIN-55,212-2 treatment was to result in a decrease in the of (Fig. and (Fig. at a of and of activation in we by and (Fig. were with and were of the active was higher in cells treated with and of WIN-55,212-2 with that at of WIN-55,212-2 and (Fig. The apoptosis are via from to active the cleavage of We that WIN-55,212-2 treatment cleavage of to (Fig. data a decrease in the protein expression of and with a increase in its by and at of and and their derivatives are drawing attention in the treatment of cancer because of their diverse activities such as cell growth inhibition, anti-inflammatory effects, and tumor regression C. de Ceballos M.L. del Pulgar T.G. Rueda D. Corbacho C. Velasco G. Galve-Roperh I. Huffman J.W. Ramon Y. Cajal S. Guzman M. Cancer Res. 2001; 61: 5784-5789PubMed Google Scholar, 7Casanova M.L. Blazquez C. Martinez-Palacio J. Villanueva C. Fernandez-Acenero M.J. Huffman J.W. Jorcano J.L. Guzman M. J. Clin. Investig. 2003; 111: 43-50Crossref PubMed Scopus (356) Google Scholar). that cannabinoid be an important for the treatment of cancer Marzo V. M. De Petrocellis L. Nat. Rev. 3: PubMed Scopus Google Scholar, Y. Cancer Res. PubMed Scopus Google Scholar, T. A. Di Marzo V. 2005; PubMed Scopus Google Scholar). We have shown that WIN-55,212-2 apoptosis of prostate cancer LNCaP cells is through CB1 and CB2 receptors and that these receptors be an important targets for the treatment of prostate cancer (11Sarfaraz S. Afaq F. Adhami V.M. Mukhtar H. Cancer Res. 2005; 65: 1635-1641Crossref PubMed Scopus (203) Google Scholar). The study was to the of the and effects of cannabinoid receptor agonist WIN-55,212-2 prostate cancer. We that WIN-55,212-2 treatment of LNCaP cells ERK1/2 leading to cell cycle dysregulation and in the ratio and caspases in an induction of apoptosis (Fig. is that growth as a of in cell cycle and is for the of most of the prostate cancer. agents that apoptosis in cancer cells be to the cell and be in the management and therapy of cancer. This because in cancer a and apoptosis is has been in and tumor with this is a to novel targets and mechanism-based apoptosis agents for the management of prostate cancer. of the most and of current cannabinoid research is the of these to the cell M. Nat. Rev. Cancer. 2003; 3: 745-755Crossref PubMed Scopus (572) Google Scholar). have shown that the induction of apoptosis be cell cycle PubMed Scopus Google Scholar, Cancer Res. 1997; PubMed Google Scholar, Rev. PubMed Scopus Google Scholar, C. J. Cancer 2000; Google Scholar, 2003; PubMed Scopus Google Scholar). we apoptosis of LNCaP cells is via cell cycle We the of WIN-55,212-2 treatment on the of cells in of the cell shown in WIN-55,212-2 treatment was to result in dose-dependent of cells in phase of the cell In recent years, inhibition of the cell cycle has been as for the management of cancer J. 2000; Google Scholar, T. H. T. Med. 2000; Scopus Google Scholar). We the of in of cell cycle arrest in LNCaP cells by WIN-55,212-2 The cell cycle in is by of protein is of cyclins that to to active are at the cell cycle and also be by Cancer Rev. PubMed Scopus Google Scholar). is by as the and protein we the in cell cycle in the phase as a of cell cycle dysregulation and apoptosis in human prostate cancer cells. is that the activities associated with the that an important in of the cell cycle G. D. T. T. PubMed Scopus Google Scholar, 1996; PubMed Scopus Google Scholar, T. 1996; PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, I. 2005; PubMed Scopus Google Scholar). have shown that cell cycle through phase and apoptosis is by D. V. C. M. D. J. PubMed Scopus Google Scholar). We observed a induction of in WIN-55,212-2-treated cells (Fig. data suggest that cell cycle dysregulation in LNCaP cells by WIN-55,212-2 treatment is by in The of cell cycle is via by and cyclins J.W. 6: PubMed Scopus Google Scholar, PubMed Scopus Google Scholar). We the of WIN-55,212-2 treatment on the cyclins and in the phase of the cell cycle, cyclins D1, D2, and (Fig. and cdk2, and (Fig. WIN-55,212-2 treatment of the cells was to result in of of these and cyclin are in phase and from to is by PubMed Scopus Google Scholar, I. 2005; PubMed Scopus Google Scholar). We observed similar when PC3 cells were treated with WIN-55,212-2 (Fig. has been that down-regulation of leads to and of with E2F inhibition of of for phase A. P. 2005; PubMed Scopus (356) Google Scholar). The of phase in the cell cycle is by the activation of E2F through the of by A. 5: PubMed Scopus Google Scholar, L. Nat. 2000; PubMed Scopus Google Scholar, I. 2005; PubMed Scopus Google Scholar). have that of are of growth because of their with to the of for cell cycle Y. 1997; PubMed Scopus Google Scholar, A. 5: PubMed Scopus Google Scholar). In the study we the protein levels and the of cell cycle arrest and apoptosis. The a dose-dependent decrease in the and E2F (Fig. and its and (Fig. is in in the The is to to a of their activation PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, J.W. Nat. 2000; PubMed Scopus Google Scholar, V. A. J. 2000; Google Scholar). data the of the cell cycle arrest and apoptosis. We observed similar when the PC3 cell was treated with WIN-55,212-2 (Fig. that treatment of human prostate cancer cell LNCaP with WIN-55,212-2 the protein expression of ERK1/2 and at higher doses of WIN-55,212-2 (Fig. The signaling is a common of cells to growth and is for ERK1/2 has a and is in cell as as cell cycle ERK1/2 activation and cell is and on many of is of we that a sustained increase in ERK1/2 expression at higher doses of WIN-55,212-2 leads to cell cycle arrest and apoptosis. was in the cell when ERK1/2 was with WIN-55,212-2 (Fig. the ERK1/2 inhibitor the of cells in phase of the cell cycle (Fig. and also the of cells when with WIN-55,212-2 treatment The ERK1/2 inhibitor also effects of WIN-55,212-2 on and cyclin in the phase of the cell cycle and an important protein (Fig. Similar were observed when ERK1/2 was (Fig. of the Bcl-2 of are of the A. V.M. Rev. 2000; PubMed Scopus Google Scholar, T. M. J. S. A. C. M.J. D.G. S. A. H. 2005; PubMed Scopus Google and be by up-regulation of p53 Bcl-2 is an in the and is as a of apoptosis PubMed Scopus Google Scholar). Bcl-2 is at levels in than of human and has shown to a with the its effects. in the levels of Bax and Bcl-2 with in the ratio of Bax/Bcl-2 is considered to be a in cells will apoptosis that cell In study, a decrease in Bcl-2 protein expression was observed in LNCaP cells WIN-55,212-2 treatment (Fig. the protein expression of Bax was to be in these cells 24 of treatment (Fig. the ratio of Bax to Bcl-2 observed in WIN-55,212-2-treated LNCaP cells apoptosis (Fig. suggest that up-regulation of and Bax and of Bcl-2 be through WIN-55,212-2 apoptosis. are are in the cells and are as are apoptosis in a A. Res. 2000; PubMed Scopus Google Scholar). of such as caspases and by leads to the activation of caspases 3, 6, and The caspases a of and the of the cell with the and Two major pathways of activation have been is by of death receptors and the activation of In the is from in to a of In the to in the of 9 G. Y. PubMed Scopus Google Scholar, A. Res. 2000; PubMed Scopus Google Scholar). WIN-55,212-2 treatment of cells was to the activation of 9 that caspases and in a dose-dependent cells were to at doses (Fig. We observed that WIN-55,212-2 treatment activation of caspases 9 and with cleavage of to the (Fig. Based on the of this study and the and as shown in the in we suggest that cannabinoid receptor agonist WIN-55,212-2 sustained and activation of ERK1/2, leads to induction of cyclin inhibitor p27/KIP1, in cell cycle in arrest and apoptosis. of pRb, protein expression of E2F of and its DP1 and leading to and apoptosis. Because Bax and Bcl-2 a in induction of of the Bax/Bcl-2 ratio in cell we that cannabinoid receptor agonist should be considered as an for the treatment of prostate cancer. is by in the of study be to cannabinoid agonist for the management of prostate cancer.
Sarfaraz et al. (Fri,) studied this question.