[Effects of Prrx2 gene silencing on the proliferation of breast cancer and its molecular mechanisms]

Objective: The aim of this study was to investigate the effects of silencing Paired related homoeobox 2 (Prrx2) expression on the proliferation of breast cancer and its molecular mechanisms. Methods: Short hairpin RNA knockdown of Prrx2 was used to examine cellular effects of Prrx2. The level of Prrx2 was verified by Western blot. MTT assay was used to analyze the proliferation of breast cancer cells in vitro. To investigate the effect of Prrx2 depletion on tumor growth in vivo, a nude mouse xenograft model was performed. Results: The expression of Prrx2 decreased 91.2% in MDA-MB-231 cells and 88.7% in MCF-7 cells after transfection with interfering vectors (P<0.05). MTT assay showed that the proliferation of cells in silenced Prrx2 expression group was significantly inhibited compared with the control group (P<0.05). Nude mice transplanted tumors showed that the growth of transplanted tumors was slow after silencing Prrx2 expression, and the weight of the tumors of silenced Prrx2 expression group were smaller than those of the control group ((160.2±26.3)mg vs (365.4±19.7)mg, P<0.05). Western blot showed that silencing Prrx2 expression inhibited the expression of β-catenin in breast cancer cell nucleus and down-regulated the activity of Wnt/β-catenin signaling pathway. Conclusions: Silencing Prrx2 expression can effectively inhibit the proliferation and growth of breast cancer, suggesting that Prrx2 may become a new target for the treatment of breast cancer.

[DNA methylation modification of BRMS1 in triple-negative breast cancer and its correlation with tumor metastasis]

Objective: To investigate the effect of methylation status of breast cancer metastasis suppressor gene 1 (BRMS1) on the expression of breast cancer and the biological behavior of cancer cells in triple-negative breast cancer (TNBC). Methods: The expression of BRMS1 in TNBC tissues and corresponding non-malignant tissues and its relationship with clinicopathological parameters were detected by immunohistochemistry. The mRNA and protein expression of BRMS1 in normal breast epithelial cells and TNBC cells were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. The methylation specific polymerase chain reaction (MSP) was used to detect the methylation status of BRMS1 in each cell. These cells were treated with demethylated preparations (5-Aza-dC) to re-activate BRMS1 expression. Using tumor cell invasion assay to detect influence of BRMS1 demethylation on the invasion capacity of cancer cells. The data were statistically analyzed. Results: The positive expression rate of BRMS1 protein in TNBC tissues was significantly lower than that in corresponding non-malignant tissues (χ(2)= 6.635, P<0.05). The mRNA expression level of BRMS1 in patients with lymph node metastasis was significantly lower than those with no lymph node metastasis (P=0.018). The down-regulation of BRMS1 expression was related to the methylation of DNA promoter, which was statistically significant (χ(2)=14.68, P<0.05). The mRNA and protein expression of BRMS1 was also correlated with tumor size and TNM staging (P=0.000-0.003). After using 5-Aza-dC, the number of cells with invasive capacity was significantly lower than those of the control group (t=3.262-10.72, P<0.05). Conclusions: The decrease of BRMS1 expression in TNBC cells is related to the methylation of DNA. Demethylation can inhibit the invasion of breast cancer cells.

Mortality among severe community-acquired pneumonia patients depends on combinations of 2007 IDSA/ATS minor criteria

OBJECTIVES

The individual 2007 Infectious Disease Society of America (IDSA)/American Thoracic Society (ATS) minor criteria for severe community-acquired pneumonia (CAP) are of unequal weight in predicting mortality. It is not clear whether the combinations of predictive findings might imply diverse severities or different mortalities.

METHODS

A prospective two centre cohort study was performed of 385 severe CAP patients fulfilling three or more IDSA/ATS minor criteria amongst 1430 patients.

RESULTS

Hospital mortality rose sharply from 5.7%, 9.9%, and 16.5%, respectively, for patients with none of three predictive findings most strongly associated to mortality (PaO2/FiO2 ≤ 250mm Hg, confusion and uraemia), one of those, and two of those to 38.6% for patients with all those (p<0.001). The number of three predictive findings present had a significantly increased odds ratio for mortality of 2.796 (p<0.001), and had the degree of positive association with sequential organ failure assessment scores at 72hours, incurring significantly longer hospital stay and higher costs.

CONCLUSIONS

Different combinations of 2007 IDSA/ATS minor criteria for severe CAP were associated to diverse severities and different mortalities. The combination of PaO2/FiO2 ≤ 250mm Hg, confusion and uraemia predicted more severity and higher mortality compared with others.