NQO1 regulates cell cycle progression at the G2/M phase.

Rationale: Overexpression of NAD(P)H:quinone oxidoreductase 1 (NQO1) is associated with tumor cell proliferation and growth in several human cancer types. However, the molecular mechanisms underlying the activity of NQO1 in cell cycle progression are currently unclear. Here, we report a novel function of NQO1 in modulation of the cell cycle regulator, cyclin-dependent kinase subunit-1 (CKS1), at the G2/M phase through effects on the stability of c­Fos. Methods: The roles of the NQO1/c-Fos/CKS1 signaling pathway in cell cycle progression were analyzed in cancer cells using synchronization of the cell cycle and flow cytometry. The mechanisms underlying NQO1/c-Fos/CKS1-mediated regulation of cell cycle progression in cancer cells were studied using siRNA approaches, overexpression systems, reporter assays, co-immunoprecipitation, pull-down assays, microarray analysis, and CDK1 kinase assays. In addition, publicly available data sets and immunohistochemistry were used to investigate the correlation between NQO1 expression levels and clinicopathological features in cancer patients. Results: Our results suggest that NQO1 directly interacts with the unstructured DNA-binding domain of c-Fos, which has been implicated in cancer proliferation, differentiation, and development as well as patient survival, and inhibits its proteasome-mediated degradation, thereby inducing CKS1 expression and regulation of cell cycle progression at the G2/M phase. Notably, a NQO1 deficiency in human cancer cell lines led to suppression of c-Fos-mediated CKS1 expression and cell cycle progression. Consistent with this, high NQO1 expression was correlated with increased CKS1 and poor prognosis in cancer patients. Conclusions: Collectively, our results support a novel regulatory role of NQO1 in the mechanism of cell cycle progression at the G2/M phase in cancer through effects on c­Fos/CKS1 signaling.

[Child Safety Injury Experiences, Prevention Behaviors and Educational Needs among Immigrant Vietnamese Women on Jeju Island]. / ì œì£¼íŠ¹ë³„ìžì¹˜ë„ 거주 ë² íŠ¸ë‚¨ 결혼 이주민 여성의 ìžë € ì•ˆì „ì‚¬ê³ ê²½í—˜ê³¼ ì•ˆì „ì‚¬ê³ ì˜ˆë°©í–‰ë™ 및 교육요구.

PURPOSE: Study purpose was to describe the child safety injury experiences, injury prevention behaviors and educational needs of immigrant Vietnamese women on Jeju Island, and to explore associations among those factors. METHODS: A descriptive correlational study was conducted using structured questionnaires to collect data from immigrant Vietnamese women who visited a multicultural centers on Jeju Island from January to April, 2017. RESULTS: Data from 60 women were analyzed. They were 28.2±5.5 years old, had resided in Korea for 40.6±31.1 months, and had 1.5±0.6 children on average. In total, 51.7% had previous injury prevention education, 68.2% had experienced child safety injuries, and 95.0% wanted to receive education on how to prevent child safety injuries. The mean total score of child injury prevention behaviors was 27.33±17.79, and that variable was associated with a longer duration of formal education (t=2.41, p=.021) and with women's experiences of child safety injury (t=5.97, p<.001). CONCLUSION: Immigrant Vietnamese women experienced a higher frequency of child safety injuries and needed educational opportunities to prevent these injuries. Further research is necessary to develop the essential content and effective methods for education on child safety injury prevention among this unique multicultural population.

Synergic induction of human periodontal ligament fibroblast cell death by nitric oxide and N-methyl-D-aspartic acid receptor antagonist.

PURPOSE: Nitric oxide (NO) has been known as an important regulator of osteoblasts and periodontal ligament cell activity. This study was performed to investigate the relationship between NO-mediated cell death of human periodontal ligament fibroblasts (PDLFs) and N-methyl-D-aspartic acid (NMDA) receptor antagonist (+)-5-methyl-10, 11-dihydro-5H-dibenzo[a,d]cyclohepten-5, 10-imine hydrogen maleate (MK801). METHODS: Human PDLFs were treated with various concentrations (0 to 4 mM) of sodium nitroprusside (SNP) with or without 200 µM MK801 in culture media for 16 hours and the cell medium was then removed and replaced by fresh medium containing MTS reagent for cell proliferation assay. Western blot analysis was performed to investigate the effects of SNP on the expression of Bax, cytochrome c, and caspase-3 proteins. The differences for each value among the sample groups were compared using analysis of variance with 95% confidence intervals. RESULTS: In the case of SNP treatment, as a NO donor, cell viability was significantly decreased in a concentration-dependent manner. In addition, a synergistic effect was shown when both SNP and NMDA receptor antagonist was added to the medium. SNP treated PDLFs exhibited a round shape in culture conditions and were dramatically reduced in cell number. SNP treatment also increased levels of apoptotic marker protein, such as Bax and cytochrome c, and reduced caspase-3 in PDLFs. Mitogen-activated protein kinase signaling was activated by treatment of SNP and NMDA receptor antagonist. CONCLUSIONS: These results suggest that excessive production of NO may induce apoptosis and that NMDA receptor may modulate NO-induced apoptosis in PDLFs.