Estrogen replacement therapy and coronary heart disease in postmenopausal women

Estrogen and promoter methylation in the regulation of PLA2G7 transcription

In the current study, cell lines including HEK293, SW480, HPASMC, HPCASMC and HAEC were cultured with 5-aza-2-deoxycytidine (DAC) and 17-β-estradiol to investigate whether PLA2G7 transcription was under the control of promoter methylation and 17-β-estradiol. Luciferase reporter gene assays were used to evaluate whether reporter gene activity was enhanced by PLA2G7 promoter fragment. Gene expression and methylation were detected using RT-PCR and pyrosequencing methods, respectively. Endogenous PLA2G7 transcription levels were found to be significantly lower in vascular related cell lines than in the other cell lines. Luciferase reporter gene assays indicated that gene activity was significantly enhanced by PLA2G7 promoter fragment. PLA2G7 transcription was found to be up-regulated with the treatment of DAC. The 17-β-estradiol was found to down-regulate PLA2G7 transcription in all the cell lines. However, 17-β-estradiol did not have significant effect on PLA2G7 methylation. Further chromatin immunoprecipitation assay showed that 17-β-estradiol might regulate gene transcription by affecting the acetylated histone H3 and H4 marks on PLA2G7 promoter. Our results showed that PLA2G7 gene expression was co-regulated by 17-β-estradiol and promoter methylation. Our findings might provide molecular clues for gender disparity in the contribution of PLA2G7 to vascular related diseases such as coronary heart disease.

Hormone replacement therapy and breast carcinoma risk in Hispanic and non-Hispanic women

BACKGROUND

Hormone replacement therapy (HRT) alleviates menopausal symptoms and prevents osteoporosis, but there is concern that long-term use may have an adverse impact on breast carcinoma risk. Epidemiologic studies report inconsistent findings regarding the relationship between HRT and postmenopausal breast carcinoma risk and there is little information on the HRT-associated risk among minority women.

METHODS

To investigate the effects of HRT on breast carcinoma risk among Hispanic women, we examined data from the New Mexico Women's Health Study (NMWHS), a statewide case-control study comprising 366 postmenopausal women with breast carcinoma and 403 controls. Conditional logistic regression was used to estimate the odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

After adjustment for sociodemographic, medical, and reproductive factors, we found an increased risk associated with long-term users of estrogen replacement therapy (ERT; OR for ERT use longer than 140 months was 2.57, 95%CI, 1.25-5.28, compared with ERT use shorter than 17 months). In addition, there was a positive trend with the duration of ERT use (P < 0.01). Hispanic postmenopausal women appeared to be at a significantly greater risk than non-Hispanic white women (OR for ERT use longer than 140 months in Hispanics was 5.53, 95%CI, 1.47-20.87; OR in non-Hispanics was 2.65, 95%CI, 0.95-7.34, compared with ERT use shorter than 17 months). In contrast, no significant association was observed for combined estrogen-progesterone use in either Hispanic or non-Hispanic women.

CONCLUSIONS

The results of this study indicated that postmenopausal women had significantly increased breast carcinoma risk for long-term ERT use. The risks among Hispanic women were substantially higher than among non-Hispanic white women although they were not statistically significant.