Low concentrations of doxycycline attenuates FasL-induced apoptosis in HeLa cells.

BACKGROUND: Doxycycline (DC) has been shown to possess non-antibiotic properties including Fas/Fas Ligand (FasL)-mediated apoptosis against several tumor types in the concentration range of 10-40 µg/mL. However, the effect of DC in apoptotic signaling at much low concentrations was not studied. METHODS: The present study investigated the attenuation effect of low dose of DC on FasL-induced apoptosis in HeLa cell by the methods of MTT assay, fluorescence microscopy, DNA fragmentation, flow cytometry analysis, and western blotting. RESULTS AND CONCLUSION: In the present findings we showed that low concentration of DC (<2.0 µg/mL) exhibited protective effects against FasL-induced apoptosis in HeLa cells. FasL treatment to HeLa cells resulted in a concentration-dependent induction of cell death, and treatment with low concentrations of DC (0.1-2 µg/mL) significantly (p < 0.001) attenuated the FasL-induced cell death as measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Further, the FasL-induced apoptotic features in HeLa cells, such as morphological changes, DNA fragmentation and cell cycle arrest was also inhibited by DC (0.5 µg/mL). Tetracycline and minocycline also showed similar anti-apoptotic effects but were not significant when compared to DC, tested at same concentrations. Further, DC (0.01-16 µg/mL) did not influence the hydrogen peroxide- or cisplatin-induced intrinsic apoptotic pathway in HeLa cells. Protein analysis using Western blotting confirmed that FasL-induced cleavage/activation of caspase-8 and caspase-3, were inhibited by DC treatment at low concentration (0.5 µg/mL). Considering the overall data, we report for the first time that DC exhibited anti-apoptotic effects at low concentrations in HeLa cells by inhibition of caspase activation via FasL-induced extrinsic pathway.

Low concentrations of doxycycline attenuates FasL-induced apoptosis in HeLa cells

BACKGROUND: Doxycycline (DC) has been shown to possess non-antibiotic properties including Fas/Fas Ligand (FasL)-mediated apoptosis against several tumor types in the concentration range of 10-40 µg/mL. However, the effect of DC in apoptotic signaling at much low concentrations was not studied. METHODS: The present study investigated the attenuation effect of low dose of DC on FasL-induced apoptosis in HeLa cell by the methods of MTT assay, fluorescence microscopy, DNA fragmentation, flow cytometry analysis, and western blotting. RESULTS AND CONCLUSION: In the present findings we showed that low concentration of DC (<2.0 µg/mL) exhibited protective effects against FasL-induced apoptosis in HeLa cells. FasL treatment to HeLa cells resulted in a concentration-dependent induction of cell death, and treatment with low concentrations of DC (0.1-2 µg/mL) significantly (p < 0.001) attenuated the FasL-induced cell death as measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazo-lium bromide (MTT) assay. Further, the FasL-induced apoptotic features in HeLa cells, such as morphological changes, DNA fragmentation and cell cycle arrest was also inhibited by DC (0.5 µg/mL). Tetracycline and minocycline also showed similar anti-apoptotic effects but were not significant when compared to DC, tested at same concentrations. Further, DC (0.01-16 µg/mL) did not influence the hydrogen peroxide- or cisplatin-induced intrinsic apoptotic pathway in HeLa cells. Protein analysis using Western blotting confirmed that FasL-induced cleavage/activation of cas-pase-8 and caspase-3, were inhibited by DC treatment at low concentration (0.5 µg/mL). Considering the overall data, we report for the first time that DC exhibited anti-apoptotic effects at low concentrations in HeLa cells by inhibition of caspase activation via FasL-induced extrinsic pathway.

Roles of estrogen receptor, progesterone receptor, p53 and p21 in pathogenesis of pelvic organ prolapse.

The aim of this study is to compare the levels of estrogen receptor (ER), progesterone receptor (PR), p53 and p21 between pelvic organ prolapse (POP) and control groups in order to evaluate their roles in pathogenesis of POP, and to find out the relationship among these proteins. Through the year of 2002, uterosacral ligaments were obtained from 20 prolapsus and 24 non-prolapsus hysterectomized uteruses. ER, PR, p53, and p21 proteins were extracted by Western blot analysis and relative levels of proteins were compared by Student t-test and Pearson correlation coefficient. P value <0.05 was considered statistically significant. All patients were postmenopausal and had never taken hormone replacement therapy. ER, PR, p53, and p21 were significantly lower in the study than control group (p<0.0001). Positive correlations were found among all proteins in the prolapse group. Further researches are needed to elucidate the interrelationship among these proteins and their precise roles in pathogenesis of POP.

The role of estrogen receptor, progesterone receptor and p53 in development of stress urinary incontinence.

Recent studies have been reported the roles of the estrogen receptor (ER), progesterone receptor (PR) and p53 in the development of a pelvic organ prolapse (POP). The pathogenesis of stress urinary incontinence (SUI) is related to that of POP in the weakness of pelvic support. Therefore, this study was carried out to assess the relationship between ER, PR, p53 and the development of SUI, and to elucidate the biomolecular pathophysiology of SUI. The periurethral fascia was obtained from 6 menopausal patients diagnosed with SUI and 10 menopausal patients without SUI who visited the Department of Obstetrics and Gynecology, Severance Hospital, Seoul, Korea. The relative ER, PR and p53 protein levels in the periurethral fascia were obtained by western blot analysis and densitometry. A Mann-Whitney U test was used for statistical analysis (p < 0.05). The mean age (+/- SD) of the 16 patients was 59.0 +/- 5.5 years (range, 50-74 years). The mean body mass index was 25.2 +/- 2.7 kg/m2 (21.8 - 30.8) and the average number of vaginal deliveries was 2.8 +/- 1.9 (1.0 - 9.0). The ER level (0.33 +/- 0.17 vs. 1.86 +/- 0.83, p= 0.02) and the p53 level (1.25 +/- 0.67 vs. 4.71 +/- 2.40, p= 0.01) were lower in the experimental group. However, the PR level of the two groups were similar (0.64 +/- 0.13 vs. 0.48 +/- 0.33, p=0.56). The p53 and ER levels were significant lower in the study group. This suggests that p53 and ER might be important factors in the development of SUI. Further prospective studies about the association of ER, p53 and SUI will be needed to elucidate the molecular pathogenesis of SUI.