Background
Cannabinoids have demonstrated anticarcinogenic properties in a variety of malignancies, including in prostate cancer. In the present study, we explored the anti‐cancer effects of the ...synthetic cannabinoid WIN 55,212‐2 (WIN) in prostate cancer.
Methods
Established prostate cancer cells (PC3, DU145, LNCaP) were treated with varying concentrations of WIN. Cell proliferation was determined by the MTS assay. The anti‐migration and anti‐invasive potential of WIN was examined by the wound healing assay and the matrigel invasion assay. Cell cycle analysis was performed by flow cytometry, and mechanistic studies were performed by Western blot. Athymic mice (n = 10) were inoculated with human PC3 cells. Once tumors reached 100 mm3, animals were randomized into two groups: saline control and WIN (5 mg/kg), delivered by intraperitoneal injection three times per week for 3 weeks.
Results
WIN significantly reduced prostate cancer cell proliferation, migration, invasion, induced apoptosis, and arrested cells in Go/G1 phase in a dose‐dependent manner. Mechanistic studies revealed these effects were mediated through a pathway involving cell cycle regulators p27, Cdk4, and pRb. Pre‐treatment with a CB2 antagonist, AM630, followed by treatment with WIN resulted in a reversal of the anti‐proliferation and cell cycle arrest previously seen with WIN alone. In vivo, administration of WIN resulted in a reduction in the tumor growth rate compared to control (P < 0.05).
Conclusions
The following study provides evidence supporting the use of WIN as a novel therapeutic for prostate cancer.
As one of the most prevalent cancers, prostate cancer has enormous public health significance and prevention strategies would attenuate its economic, emotional, physical and social impact. Until ...recently, however, we have had only modest information about risk factors for this disease, apart from the well-established characteristics of age, family history and place of birth. The large worldwide variation in the incidence of prostate cancer and the increased risk in migrants who move from low-risk to high-risk countries provide strong support for modifiable environmental factors, particularly diet, in its etiology. Thus, dietary agents have gained considerable attention as chemopreventive agents against prostate cancer. Dietary fat, red and processed meat, vitamin E, selenium, tomatoes, cruciforms and green tea have all been linked with the development and aggressiveness of prostate cancer, through a range of molecular mechanisms. The direction of future clinical trials lies in clarifying the effects of these agents and exploring the biological mechanisms responsible for the prevention of prostate cancer. However, owing to the short time period between diagnosis and treatment, conventional dietary intervention techniques are not always realistic. Until large randomized trials confirm the benefit of chemopreventive and dietary modifications, patients can be advised to pursue a diet and lifestyle that enhances overall health.
Prostate cancer risk calculators incorporate many factors to evaluate an individual's risk for prostate cancer. We validated two common North American-based, prostate cancer risk calculators.
We ...conducted a prospective, multi-institutional study of 2,130 patients who underwent a prostate biopsy for prostate cancer detection from five centers. We evaluated the performance of the Sunnybrook nomogram-based prostate cancer risk calculator (SRC) and the Prostate Cancer Prevention Trial (PCPT) -based risk calculator (PRC) to predict the presence of any cancer and high-grade cancer. We examined discrimination, calibration, and decision curve analysis techniques to evaluate the prediction models.
Of the 2,130 patients, 867 men (40.7%) were found to have cancer, and 1,263 (59.3%) did not have cancer. Of the patients with cancer, 403 (46.5%) had a Gleason score of 7 or more. The area under the concentration-time curve (AUC) for the SRC was 0.67 (95% CI, 0.65 to 0.69); the AUC for the PRC was 0.61 (95% CI, 0.59 to 0.64). The AUC was higher for predicting aggressive disease from the SRC (0.72; 95% CI, 0.70 to 0.75) compared with that from the PRC (0.67; 95% CI, 0.64 to 0.70). Decision curve analyses showed that the SRC performed better than the PRC for risk thresholds of more than 30% for any cancer and more than 15% for aggressive cancer.
The SRC performed better than the PRC, but neither one added clinical benefit for risk thresholds of less than 30%. Further research is needed to improve the AUCs of the risk calculators, particularly for higher-grade cancer.
The prostate-specific gene, TMPRSS2, is fused with the transcription factor gene, ERG in a high proportion of prostate cancers. However, the clinical significance of TMPRSS2:ERG gene fusion among ...prostate cancer patients is unknown. We assayed for the presence of the TMPRSS2:ERG gene fusion product among 26 patients who underwent surgery for clinically localized prostate cancer using RT-PCR and direct DNA sequencing, and evaluated its prognostic significance. All 26 patients had cancers of the same histologic grade (Gleason score 7). The fusion protein was present within prostate cancer tumor cells in eleven patients (42.3%). Nine patients experienced biochemical disease relapse (elevated PSA) after a mean follow-up of 12 months (range 1 to 48 months). Patients with the fusion protein had a significantly higher rate of recurrence (5-year recurrence rate 79.5%) compared to patients who lacked the fusion protein (5-year recurrence rate 37.5%, p=0.009). The adjusted hazard ratio for disease relapse for patients with the fusion protein was 7.1 (95% C.I.: 1.1 - 45, p = 0.03) compared to patients without the fusion protein. In multivariate analysis, the presence of gene fusion was the single most important prognostic factor. Our study indicates that the expression of TMPRSS2:ERG fusion gene among prostate cancer patients treated with surgery is a strong prognostic factor for disease relapse, and may have important clinical implications.
Promoter and 5' end methylation regulation of tumour suppressor genes is a common feature of many cancers. Such occurrences often lead to the silencing of these key genes and thus they may contribute ...to the development of cancer, including prostate cancer.
In order to identify methylation changes in prostate cancer, we performed a genome-wide analysis of DNA methylation using Agilent human CpG island arrays. Using computational and gene-specific validation approaches we have identified a large number of potential epigenetic biomarkers of prostate cancer. Further validation of candidate genes on a separate cohort of low and high grade prostate cancers by quantitative MethyLight analysis has allowed us to confirm DNA hypermethylation of HOXD3 and BMP7, two genes that may play a role in the development of high grade tumours. We also show that promoter hypermethylation is responsible for downregulated expression of these genes in the DU-145 PCa cell line.
This study identifies novel epigenetic biomarkers of prostate cancer and prostate cancer progression, and provides a global assessment of DNA methylation in prostate cancer.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Purpose: Several single nucleotide polymorphisms (SNP) have been associated with the risk of prostate cancer. The clinical utility
of using SNPs in the early detection of prostate cancer has not been ...evaluated.
Experimental Design: We examined a panel of 25 SNPs from candidate genes and chromosomal regions in 3,004 unselected men who were screened for
prostate cancer using serum prostate-specific antigen (PSA) and digital rectal examination. All underwent a prostate biopsy.
We evaluated the ability of these SNPs to help predict the presence of prostate cancer at biopsy.
Results: Of the 3,004 patients, 1,389 (46.2%) were found to have prostate cancer. Fifteen of the 25 SNPs studied were significantly
associated with prostate cancer ( P = 0.02-7 × 10 −8 ). We selected a combination of 4 SNPs with the best predictive value for further study. After adjusting for other predictive
factors, the odds ratio for patients with all four of the variant genotypes compared with men with no variant genotype was
5.1 (95% confidence interval, 1.6-16.5; P = 0.006). When incorporated into a nomogram, genotype status contributed more significantly than PSA, family history, ethnicity,
urinary symptoms, and digital rectal examination (area under the curve = 0.74). The positive predictive value of the PSA test
ranged from 42% to 94% depending on the number of variant genotypes carried ( P = 1 × 10 −15 ).
Conclusions: SNP genotyping can be used in a clinical setting for the early detection of prostate cancer in a nomogram approach and by
improving the positive predictive value of the PSA test.
Purpose: To identify and examine polymorphisms of genes associated with aggressive and clinical significant forms of prostate cancer among a screening cohort.
Experimental Design: We conducted a ...genome-wide association study among patients with aggressive forms of prostate cancer and biopsy-proven normal controls ascertained from a prostate cancer screening program. We then examined significant associations of specific polymorphisms among a prostate cancer screened cohort to examine their predictive ability in detecting prostate cancer.
Results: We found significant associations between aggressive prostate cancer and five single nucleotide polymorphisms (SNPs) in the 10q26 (rs10788165, rs10749408, and rs10788165, p value for association 1.3 × 10
−10
to 3.2 × 10
−11
) and 15q21 (rs4775302 and rs1994198, p values for association 3.1 × 10
−8
to 8.2 × 10
−9
) regions. Results of a replication study done in 3439 patients undergoing a prostate biopsy, revealed certain combinations of these SNPs to be significantly associated not only with prostate cancer but with aggressive forms of prostate cancer using an established classification criterion for prostate cancer progression (odds ratios for intermediate to high-risk disease 1.8-3.0, p value 0.003-0.001). These SNP combinations were also important clinical predictors for prostate cancer detection based on nomogram analysis that assesses prostate cancer risk.
Conclusions: Five SNPs were found to be associated with aggressive forms of prostate cancer. We demonstrated potential clinical applications of these associations.
Epidemiological studies have suggested an association between selenium intake and protection from a variety of cancer. Considering this clinical importance of selenium, we aimed to identify the genes ...associated with resistance to selenium treatment. We have applied a previous methodology developed by our group, which is based on the genetic and pharmacological data publicly available for the NCI60 cancer cell line panel. In short, we have categorized the NCI60 cell lines as selenium resistant and sensitive based on their growth inhibition (GI50) data. Then, we have utilized the Affymetrix 125K SNP chip data available and carried out a genome-wide case-control association study for the selenium sensitive and resistant NCI60 cell lines. Our results showed statistically significant association of four SNPs in 5q33-34, 10q11.2, 10q22.3 and 14q13.1 with selenium resistance. These SNPs were located in introns of the genes encoding for a kinase-scaffolding protein (AKAP6), a membrane protein (SGCD), a channel protein (KCNMA1), and a protein kinase (PRKG1). The knock-down of KCNMA1 by siRNA showed increased sensitivity to selenium in both LNCaP and PC3 cell lines. Furthermore, SNP-SNP interaction (epistasis) analysis indicated the interactions of the SNPs in AKAP6 with SGCD as well as SNPs in AKAP6 with KCNMA1 with each other, assuming additive genetic model. These genes were also all involved in the Ca(2+) signaling, which has a direct role in induction of apoptosis and induction of apoptosis in tumor cells is consistent with the chemopreventive action of selenium. Once our findings are further validated, this knowledge can be translated into clinics where individuals who can benefit from the chemopreventive characteristics of the selenium supplementation will be easily identified using a simple DNA analysis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Cannabinoids have demonstrated anticarcinogenic properties in a variety of malignancies, including prostate cancer. WIN 55,212-2 (WIN) is a highly potent synthetic cannabinoid that binds to ...cannabinoid receptors (CB1 and CB2). We have previously demonstrated that WIN significantly reduces prostate cancer cell proliferation, migration, invasion, induces apoptosis, and arrests cells in the G0/G1 phase through a cannabinoid receptor 2 dependent manner. We also determined that these effects were mediated though a pathway involving cell cycle regulators p27, Cdk4, and pRb. The current study aims to examine the role of endoplasmic reticulum (ER) stress in apoptosis and investigates whether this effect is modulated by WIN and the cannabinoid receptors.
In this study, we evaluated the effect of WIN and CB receptors on ER stress induced apoptosis in established prostate cancer cells (DU145, PC3). Cells were treated with WIN, cannabinoid receptor 1 antagonist (AM251), and cannabinoid receptor 2 antagonist (AM630). Cell proliferation was determined using MTS assays. Quantitative PCR was used to examine changes in expression of ER stress related genes, including CHOP, TRIB3, and ATF4. Western blotting will be completed to determine changes in the expression of apoptotic markers after treatment with WIN and cannabinoid antagonists. Further studies are ongoing looking at the use of the ER stress inhibitor, Salubrinal, to determine whether ER stress is vital for WIN-induced apoptosis.
Our results reveal that treatment with 20μM WIN resulted in a significant reduction in the proliferation of DU145 and PC3 cells after 24 h compared to control (p<0.05). In contrast, treatment with 5μM of either AM251 or AM630 did not result in any significant changes in cell proliferation. Quantitative PCR studies revealed significant upregulation of ER stress genes CHOP, TRIB3 and ATF4 in WIN treated cells (p<0.05). Expression of ER stress genes were significantly downregulated after blocking CB1 and CB2 receptors (p<0.05).
Interim results suggest that WIN has significant antitumoral activity and modulates ER stress-induced apoptosis in prostate cancer cells, thus, may offer a novel therapeutic strategy in the treatment of prostate cancer.
Citation Format: Domenica Roberto, Laurence H. Klotz, Vasundara Venkateswaran. Cannabinoid WIN 55,212-2 induces endoplasmic reticulum stress in prostate cancer cells through CB1and CB2receptors abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4805.
Vitamin E has been identified as a candidate agent for the prevention of prostate cancer. We hypothesize that the mechanism for this effect is in part a result of cell cycle inhibition rather than ...only due to a reduction in reactive oxygen species. We tested whether vitamin E induces cell cycle arrest in prostate carcinoma, mediated by alterations in cell cycle regulatory proteins, including cyclin E, cdk2 and p27.
Cells were incubated with and without vitamin E (α-tocopherol succinate, 20 μg./ml.), fixed and stained with propidium iodide for flow cytometry analysis. In parallel experiments total protein was extracted, immunoprecipitated with cyclin E antibody and analyzed by Western blot for the expression of cell cycle markers.
Flow cytometry analysis revealed a dramatic reduction in the S phase percent of LNCaP and PC3 cells in response to vitamin E (69% and 95%, respectively). It was accompanied by over expression of p27 (3-fold increase) with vitamin E treatment.
This study demonstrates that at physiological concentrations vitamin E induced profound cell cycle arrest mediated by up-regulation of p27. This observation provides a theoretical basis for the putative chemopreventive effect of vitamin E.
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