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Involvement of the CB 2 cannabinoid receptor in cell growth inhibition and G0/G1 cell cycle arrest via the cannabinoid agonist WIN 55,212-2 in renal cell carcinoma.

Authors :
Khan MI
Sobocińska AA
Brodaczewska KK
Zielniok K
Gajewska M
Kieda C
Czarnecka AM
Szczylik C
Source :
BMC cancer [BMC Cancer] 2018 May 23; Vol. 18 (1), pp. 583. Date of Electronic Publication: 2018 May 23.
Publication Year :
2018

Abstract

Background: The anti-tumor properties of cannabinoids have been investigated in many in vitro and in vivo studies. Many of these anti-tumor effects are mediated via cannabinoid receptor types 1 and 2 (CB <subscript>1</subscript> and CB <subscript>2</subscript> ), comprising the endocannabinoid system (ECS). In this study, we investigated the ECS based on CB <subscript>1</subscript> and CB <subscript>2</subscript> receptor gene and protein expression in renal cell carcinoma (RCC) cell lines. In view of their further use for potential treatments, we thus investigated the roles of CB <subscript>1</subscript> and CB <subscript>2</subscript> receptors in the anti-proliferative action and signal transduction triggered by synthetic cannabinoid agonists [such as JWH-133 and WIN 55,212-2 (WIN-55)] in RCC cell lines.<br />Methods: Human RCC cell lines were used for this study. The CB <subscript>1</subscript> and CB <subscript>2</subscript> gene expression levels were analyzed using real-time PCR. Flow cytometric, immunocytochemical and western blot analyses were performed to confirm CB <subscript>1</subscript> and CB <subscript>2</subscript> receptor protein expression. The anti-proliferative effects of synthetic cannabinoids were investigated on cell viability assay. The CB <subscript>1</subscript> and CB <subscript>2</subscript> receptors were blocked pharmacologically with the antagonists SR141716A and AM-630, respectively, to investigate the effects of the agonists JWH-133 and WIN-55. Cell cycle, apoptosis and LDH-based cytotoxicity were analyzed on cannabinoid-treated RCC cells.<br />Results: The CB1 and CB2 genes expression was shown by real-time PCR and flow cytometric and western blot analysis indicating a higher level of CB <subscript>2</subscript> receptor as compared to CB <subscript>1</subscript> in RCC cells. Immunocytochemical staining also confirmed the expression of the CB <subscript>1</subscript> and CB <subscript>2</subscript> proteins. We also found that the synthetic cannabinoid agonist WIN-55 exerted anti-proliferative and cytotoxic effects by inhibiting the growth of RCC cell lines, while the CB <subscript>2</subscript> agonist JWH-133 did not. Pharmacologically blocking the CB1 and CB2 receptors with their respective antagonists SR141716A and AM-630, followed by the WIN-55 treatment of RCC cells allowed uncovering the involvement of CB2, which led to an arrest in the G0/G1 phase of the cell cycle and apoptosis.<br />Conclusions: This study elucidated the involvement of CB <subscript>2</subscript> in the in vitro inhibition of RCC cells, and future applications of CB <subscript>2</subscript> agonists in the prevention and management of RCC are discussed.

Details

Language :
English
ISSN :
1471-2407
Volume :
18
Issue :
1
Database :
MEDLINE
Journal :
BMC cancer
Publication Type :
Academic Journal
Accession number :
29792186
Full Text :
https://doi.org/10.1186/s12885-018-4496-1