Downregulation of TMPRSS4 Enhances Triple-Negative Breast Cancer Cell Radiosensitivity Through Cell Cycle and Cell Apoptosis Process Impairment.

BACKGROUND: Radioresistance remains a challenge for cancer radiotherapy. The present study aims to investigate the role of TMPRSS4 in triple negative breast cancer (TNBC) cell radiosensitivity. MATERIALS AND METHODS: After transfection of MDA-MD-468 triple negative breast cancer cells line by using the lentivirus vector, the effect of TMPRSS4 down-regulation on TNBC radiosensitivity was evaluated by using cloning assay and CCK-8 assay. The CCK-8 assay was also used for performing cell proliferation analysis. Western blot was carried out to detect the expression of certain proteins related to cell cycle pathways (cyclin D1), cell apoptosis pathways (Bax, Bcl2, and Caspase3), DNA damage and DNA damage repair (TRF2, Ku80 , Ë H2AX) . The cell cycle and cell apoptosis were also investigated using flow cytometer analysis. RESULTS: TMPRSS4 expression was down-regulated in MDA-MB-468 cells which enhanced MDA-MB-468 cells radiosensitivity. TMPRSS4 silencing also improved IR induced cell proliferation ability reduction and promoted cell arrested at G2/M phase mediated by 6 Gy IR associated with cyclin D1 expression inhibition. Moreover, TMPRSS4 inhibition enhanced TNBC apoptosis induced by 6 Gy IR following by over-expression of (Bax, Caspase3) and down-regulation of Bcl2 as the pro-apoptotic and anti-apoptotic proteins, respectively. Otherwise, TMPRSS4 down-regulation increases  DNA damage induced by 6 Gy IR and delays DNA damage repair respectively illustrated by downregulation of TRF2 and permanent increase of Ku80 and Ë H2AX expression at 1 h and 10 h post-IR. CONCLUSION: Down-regulation of TMPRSS4 increases triple negative breast cancer cell radiosensitivity and the use of TMPRSS4 inhibitor can be encouraged for improving radiotherapy effectiveness in TNBC radioresistant patients.

Role of TMPRSS4 Modulation in Breast Cancer Cell Proliferation.

Background: TMPRSS4 is a novel Type II transmembrane serine protease found at the surface of the cells and is involved in the development and cancer progression. However, TMPRSS4 functions in breast cancer remain poor understand. The present study investigated the function of TMPRSS4 in the breast cancer cells and the potential mechanistic action underling. Materials and Methods: The lentiviral vectors causing TMPRSS4 down-regulation and over-expression were established and transfected in MDA-MB-468 and MCF-7 cells, respectively. By using the CCK- 8 assay, cell proliferation was analyzed. Moreover, western blot was used to detect the expression of certain proteins related to cell apoptosis (Bax and Bcl2) signaling pathway and telomere maintenance (POT1, TPP1, and UBE2D3). Cell cycle and cell apoptosis were also analyzed by using the Flow cytometry analysis. TMPRSS4 expression was detected at the mRNA level and protein level by performing qPCR and western blot technique, respectively. Results: TMPRSS4 expression is inhibited in stable transfected MDA-MB-468-shTMPRSS4 cells compared to the control MDA-MB-468-NC and its expression is up-regulated in stable transfected MCF-7-TMPTSS4 compared to its control MCF-7-NC. Moreover, TMPRSS4 silencing in breast cancer reduces cells proliferation by promoting cell cycle arrest in G2/M phase, cell apoptosis, and telomere maintenance impairment while the TMPRSS4 overexpression increases cells proliferation through cell apoptosis reduction and telomere maintenance reinforcement associated with insignificant change in cell cycle progression. Conclusion: TMPRSS4 plays important roles in cancer progression and may be considered as a good therapeutic target for cancer gene therapy especially breast cancer.

Detecting the polymorphisms of paraoxonase (PON) cluster in Chinese Han population based on a rapid method.

BACKGROUND: An increased risk of coronary heart disease has been shown to be associated with polymorphisms in PON1 gene in different populations. Polymorphisms in PON2 gene have been associated with the level of plasma lipoproteins and glucose and are thought to play a role in atherosclerosis. METHODS: To detect PONs polymorphisms more rapidly and reliably, we modified and improved the method established by Motti et al. We redesigned the primer for amplifying the common polymorphism at position 311 of PON2, which produced more reliable and efficient amplification. RESULTS: A second common polymorphism at codon 148 was also detected by our new method, as were the 2 polymorphisms in the PON1 gene. The new method allowed identification of 4 polymorphisms (PON1-192, PON1-55, PON2-148 and PON2-311) simultaneously. The PONs genotypes of 82 healthy persons were identified by this method. The allelic frequencies were: PON1-192: Q 46.3%, R 53.7%; PON1-55: L 95.1%, M 4.9%; PON2-148: A 85.4%, G 14.6%; PON2-311: S 77.4%, and C 22.6%, respectively. CONCLUSION: This method represents a simple, economical and time-saving technique to simultaneously detect 4 polymorphisms in the PON cluster. It provides a useful application to enable further study of the relationship between PON1 and PON2 and their role in atherosclerosis.

Association study between fibronectin and coronary heart disease.

Fibronectin is a known chemoattractant for several cell types that play a role in the wound healing process, including fibroblasts, endothelial cells and macrophages. It also generates a scaffold that allows attachment of other extracellular matrix components. Large amounts of fibronectin have been detected in atherosclerotic plaques, suggesting that it may play a role in the pathogenesis of atherosclerosis. To examine the possible involvement of fibronectin in the etiology of atherosclerotic coronary heart disease, we analyzed four polymorphisms in the human fibronectin gene and determined the plasma fibronectin levels in patients with coronary heart disease (n = 109) and age- and gender-matched controls (n = 123) in Chinese Han people. No significant positive association was observed between these polymorphisms and coronary heart disease. The levels of circulating plasma fibronectin, however, were significantly lower in patients with coronary heart disease (mean +/- SD 245 +/- 87 mg/L) compared with controls (354 +/- 88 mg/L) (p < 0.001). The odds ratio (OR) for plasma fibronectin was 0.94 in a multivariate unconditional logistic regression model (OR = 0.94, 95% CI 0.91-0.96, p < 0.001). We conclude that, in our population, the four fibronectin gene polymorphisms detected are not associated with clinical coronary heart disease. Our data suggest that low circulating fibronectin levels might be a new marker of coronary heart disease.