| Summary: | 碩士 === 國立陽明大學 === 生理學研究所 === 97 === The process of ovulation is the key event for reproduction and therefore should be well-regulated. Ovarian hyperstimulation syndrome (OHSS), which results from excess production of some factors during ovulation, has been recognized as a dramatic complication of gonodotrophin therapy. Since ovulation has been proposed to be associated with inflammatory responses, inflammatory factors may be implicated in the occurrence of OHSS. In addition, ovarian granulosa cell tumor (GCT) is most commonly found in women between peri- and post-menopausal ages; therefore a hypothesis arises that ovarian hyperstimulation may lead to carcinogenesis of granulosa cells, which are implicated in sex hormone and growth factor production during ovarian development. Among the multiple cytokines that regulate ovarian functions, interleukin (IL)-1b is about the best-known one that have been characterized as an indicator of several cancers and could mediate the expression of other pro-inflammatory factors, such as IL-8 and cyclooxygenase 2 (COX)-2, which in turn participate in the process of ovulation. On the other hand, non-steroidal anti-inflammatory drugs (NSAIDs), for example NS-398, in addition to its traditional anti-inflammatory feature, it has also been proposed as a potential option to retard cancer development. Here we presented that, instead of attenuating the inflammatory response, NS-398 further enhanced IL-1b-induced COX-2 and IL-8 mRNA and protein expression as well as IL-8 secretion in human granulosa KGN cell line. We also examined on whether NS-398 would enhance the protein stability of COX-2 and IL-8 and we found that NS-398 did not have post-translational effect, indicating that NS-398 may act mostly at the transcriptional level. To evaluate what signaling pathways are involved in the enhancement effect by NS-398, we pretreated KGN cells with inhibitors of MAPK (ERK, JNK, p38) as well as NF-kB before the inclusion of IL-1b in the absence or presence of NS-398. Inhibition of MAPKs and NF-kB significantly reduced NS-398-mediated enhancement on IL-1b-induced COX-2 and IL-8 expression. We also found that NS-398 could promote IL-1b-mediated NF-kB p65 translocation from cytosol into nucleus but have no effect on MAPK phosphorylation. These results suggest that NS-398 may augment IL-1b-induced COX-2 and IL-8 expression through NF-kB signal pathways. In addition, IL-8 appeared to increase proliferation of KGN cells according to the alamarBlue assay. NS-398 combined with IL-1b could reduce p21waf-1/cip-1 and p27kip-1 expression, which are regulators of cell cycle. In conclusion, our data identify a novel role of NS-398 that it could amplify IL-1b-induced COX-2 and IL-8 expression possibly through an NF-kB signal pathway; the increase of IL-8 secretion may contribute to proliferation of granulosa tumor cells and NS-398 combined with IL-1b might mediate cell cycle through down-regulating p21waf-1/cip-1 and p27kip-1 expression.
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