Forskolin and Phorbol 12-myristate 13-acetate modulates the expression pattern of AP-1 factors and cell cycle regulators in estrogen-responsive MCF-7 cells

Effect of APOBEC3A functional polymorphism on renal cell carcinoma is influenced by tumor necrosis factor-α and transcriptional repressor ETS1

Human apolipoprotein B mRNA editing enzyme, catalytic polypeptide (APOBEC) 3 cytidine deaminases are the prominent drivers of somatic mutations in cancers. However, the effect of APOBEC3s functional polymorphisms on the development of renal cell carcinoma (RCC) remains unknown. Five genetic polymorphisms affecting the expression of APOBEC3A (A3A), APOBEC3B, and APOBEC4 and uracil DNA glycosylase (UNG) were genotyped in 728 RCC patients and 1500 healthy controls. The effects of tumor necrosis factor-α (TNFα) and interleukin-6 on the activity of the A3A promoter with rs12157810-A or -C in four RCC cell lines (786-O, A498, Caki2, ACHN) and two colorectal cancer cell lines (HCT116, SW620) were evaluated using dual-luciferase assays. Transcriptional repressors to the A3A promoter were identified by chromatin immunoprecipitation-quantitative PCR. The proapoptotic effect of A3A on RCC cells was evaluated using cytometry. The prognostic values of A3A and ETS1 were evaluated by the Cox regression analysis. The expressions of A3A and ETS1 were evaluated in clear cell RCC (ccRCC) specimens with different polymorphic genotypes using quantitative RT-PCR and immunohistochemistry. Of those functional polymorphisms, CC genotype at rs12157810 in the A3A promoter was significantly associated with a decreased risk of ccRCC, compared to the AA genotype (odds ratio adjusted for age and gender, 0.41, 95% confidence interval [CI], 0.28-0.57). Other polymorphic genotypes were not associated with the risk of RCC. The activity of the A3A promoter with rs12157810-C was significantly higher than that with rs12157810-A in the four RCC cell lines and two colorectal cancer cell lines. The activity of the A3A promoter with rs12157810-C was greatly up-regulated by TNFα and predominantly inhibited by a transcriptional repressor ETS1. The binding of ETS1 to the A3A promoter with rs12157810-C was looser than that with rs12157810-A. Ectopic expression of A3A significantly promoted apoptosis in ccRCC cells, rather than in colorectal cancer cells. Higher ETS1 expression predicted a favorable prognosis in ccRCC, with a hazard ratio of 0.58 (95% CI, 0.43-0.78). Rs121567810-C up-regulates the A3A promoter activity, possibly due to higher response to TNFα and looser transcriptional repression by ETS1. Up-regulation of A3A increases apoptosis, thus decreasing ccRCC risk in those carrying rs121567810-C.

Multiple bioanalytical methods reveal a thyroid-disrupting mechanism related to the membrane receptor integrin αvβ3

Di(2-ethylhexyl) phthalate (DEHP), a manufactured chemical, is suitable for large-scale production and has extensive applications. Although restricted for use, DEHP is still ubiquitous in the environment and shows potential to disrupt the structure or function of the thyroid system. However, its toxic mechanism is complex and not clearly understood. In this study, a battery of methods was employed to investigate DEHP-induced thyroid-disrupting effects and their mechanism of action, focusing on a newly discovered membrane receptor-mediated mechanism. The results showed that DEHP promoted rat pituitary tumor (GH3) cell proliferation and c-fos gene expression at environment level concentrations (2 and 5 μmol/L) in a manner similar to that of the natural thyroid hormone 3,3',5-triiodo-L-thyronine (T3). The macromolecule DEHP-BSA cannot pass through the cell membrane to interact with nuclear receptors but upregulated the c-fos gene expression when administered at concentrations comparable to DEHP concentrations; molecular docking demonstrated that DEHP has affinity for the membrane receptor integrin α_vβ₃; DEHP at 2 μmol/L upregulated the β₃ gene expression in GH3 cells; after the addition of integrin α_vβ₃-inhibiting RGD peptide, DEHP-induced c-fos gene upregulation decreased. All of these findings support the supposition that DEHP-induced thyroid-disrupting effects might be mediated by the membrane receptor integrin α_vβ₃. Moreover, DEHP activated the downstream extracellular regulated protein kinase (ERK1/2) pathway, upregulating the gene expression of raf-1, MEK-1 and MAPK1 and increasing the protein levels of p-ERK; interestingly, ERK1/2 activation and c-fos upregulation induced by DEHP were attenuated by PD98059 (an ERK1/2 inhibitor). Taken together, the data suggest that the membrane receptor integrin α_vβ₃ and the downstream ERK1/2 pathway might be involved in DEHP-induced thyroid-disrupting effects. This study provides new insight into the thyroid-disrupting effect and the underlying mechanism and will advance the effort to construct adverse outcome pathways of DEHP and other thyroid hormone disrupting chemicals.