Occupation and prostate Cancer risk: results from the epidemiological study of prostate cancer (EPICAP)

Aridanin and oleanane-3- O-β-D-glucoside-2'-acetamide obtained from Tetrapleura tetraptera (Schumach. & Thonn) Taub. (Fabaceae) induces potent apoptotic activity in human prostate cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Tetrapleura tetraptera (Schumach. and Thonn.) Taub. (Fabaceae) is a tropical plant that is used in Cameroon pharmacopeia for the treatment of many cancers including prostate cancer (PCa), which is a major cause of men's death worldwide. The objective of this study was to evaluate the anticancer properties as well as underlying mechanisms of isolates from T. tetraptera on DU145, PC3 and LNCaP cancer cell lines.

MATERIALS AND METHODS

Eight (8) compounds were purified from T. tetraptera stem bark extract through silica gel column chromatography (CC) and characterized using spectroscopic techniques (1D and 2D NMR), HRESIMS. Cell growth was assessed by a well-characterized MTT assay, while BrdU and clonogenicity assays provided information on the cell proliferation index. Further, the impact of the compounds on cell cycle progression and cell death were performed through Flow cytometry. Cell adhesion, cell migration and chemotaxis along with some proteins of epithelial-mesenchymal transition (EMT) were assayed.

RESULTS

Out of the eight (1-8) isolates from T. tetraptera only oleanane-3-O-β-D-glucoside-2'-acetamide and aridanin showed potent cell growth arrest with an estimated CC50 of 15, 23, 16 and 17, 26, 16 μg/mL on DU145, PC3 and LNCaP cells, respectively. A 15% (DU145) and 25% (LNCaP) increase in apoptotic cells induced by oleanane-3-O-β-D-glucoside-2'-acetamide and aridanin at 10 μg/mL were noticed. Oleanane-3-O-β-D-glucoside-2'-acetamide and aridanin at 2.5 and 10 μg/mL reduced the number of cells in S-phase and raised cells in G2/M phase. At the same concentrations, they decreased the number of invading DU145 cells and increased the adherence of DU145 cells to fibronectin and collagen matrix at tested concentrations, accompanied by an increase in integrin β-1 (10 μg/mL) and integrin β-4 (2.5 μg/mL) expression. Furthermore, a down-regulation of pcdk1, cdk2, Bcl-2, N-Cad, vimentin and cytokeratine 8-18 was noticed while, p19, p27, p53 pAKT, Bax, caspase-3 and E-Cad were up-regulated.

CONCLUSIONS

This study outlines for the first time, the anticancer ability of compounds oleanane-3-O-β-D-glucoside-2'-acetamide (4) and aridanin (6) from Tetrapleura tetraptera and proposes their putative mechanisms of action.

A Genome-Wide Association Study of Prostate Cancer Susceptibility Using Occupational and Environmental Factors as Confounding Factors

Background In addition to genetic predisposition, occupational and environmental factors are important for the risk of prostate cancer. We investigated the effect of single nucleotide polymorphisms (SNPs) on the development of prostate cancer in Japan, including occupational and industrial history as confounding factors in addition to age, smoking, and alcohol drinking. Methods We enrolled 210 prostate cancer patients and 504 male control patients. We conducted four genome-wide association study (GWAS) patterns for prostate cancer development. In the association test, logistic regression models incorporated age, smoking history, alcohol consumption history, and each pattern of industrial/occupational classification. Results No SNPs satisfying the genome-wide significance level of 5×10-8 were detected in GWAS. SNPs with a suggestive association level of 1×10-6 were found near the long intergenic non-protein coding RNA 1824 (LINC01824) and tripartite motif family like 2 (TRIML2) genes in the GWAS using occupational history as a confounder and near the ribosomal protein S2 pseudogene 25 (RPS2P25) gene in the GWAS using industrial history as a confounder. No SNPs that met the suggestive association level were observed in the GWAS that did not include occupational and industrial history. Conclusion By adding occupational and industrial history to the confounding factors, there were SNPs detected in the GWAS for prostate cancer development. The consideration of occupational and industrial history may increase the usefulness of GWAS.

Association of occupational heat exposure and colorectal cancer in the MCC-Spain study

OBJECTIVE

Heat exposure and heat stress/strain is a concern for many workers. There is increasing interest in potential chronic health effects of occupational heat exposure, including cancer risk. We examined potential associations of occupational heat exposure and colorectal cancer (CRC) risk in a large Spanish multi-case--control study.

METHODS

We analyzed data on 1198 histologically confirmed CRC cases and 2690 frequency-matched controls. The Spanish job-exposure matrix, MatEmEsp, was used to assign heat exposure estimates to the lifetime occupations of participants. Three exposure indices were assessed: ever versus never exposed, cumulative exposure and duration (years). We estimated odds ratios (OR) and 95% confidence intervals (CI) using unconditional logistic regression adjusting for potential confounders.

RESULTS

Overall, there was no association of ever, compared with never, occupational heat exposure and CRC (OR 1.09, 95% CI 0.92-1.29). There were also no associations observed according to categories of cumulative exposure or duration, and there was no evidence for a trend. There was no clear association of ever occupational heat exposure and CRC in analysis conducted among either men or women when analyzed separately. Positive associations were observed among women in the highest categories of cumulative exposure (OR 1.81, 95% CI 1.09-3.03) and duration (OR 2.89, 95% CI 1.50-5.59) as well as some evidence for a trend (P<0.05).

CONCLUSION

Overall, this study provides no clear evidence for an association between occupational heat exposure and CRC.

Mitochondrial Sirtuins in Chronic Degenerative Diseases: New Metabolic Targets in Colorectal Cancer

Sirtuins (SIRTs) are a family of class III histone deacetylases (HDACs) consisting of seven members, widely expressed in mammals. SIRTs mainly participate in metabolic homeostasis, DNA damage repair, cell survival, and differentiation, as well as other cancer-related biological processes. Growing evidence shows that SIRTs have pivotal roles in chronic degenerative diseases, including colorectal cancer (CRC), the third most frequent malignant disease worldwide. Metabolic alterations are gaining attention in the context of CRC development and progression, with mitochondrion representing a crucial point of complex and intricate molecular mechanisms. Mitochondrial SIRTs, SIRT2, SIRT3, SIRT4 and SIRT5, control mitochondrial homeostasis and dynamics. Here, we provide a comprehensive review on the latest advances on the role of mitochondrial SIRTs in the initiation, promotion and progression of CRC. A deeper understanding of the pathways by which mitochondrial SIRTs control CRC metabolism may provide new molecular targets for future innovative strategies for CRC prevention and therapy.