Mouse Anti-Human IL-8 Hybridoma [B6.23.25]

Age-related macular degeneration (AMD) is a leading cause of irreversible blindness worldwide. Oxidative stress (OS), inflammation and genetics are considered the key pathogenic factors contributing to AMD development. Recent evidence shows the pro-inflammatory interleukin 17 (IL17) signaling is activated in AMD patients and promotes disease pathogenesis. However, the interplay between OS and IL17 signaling, and the regulatory mechanism of IL17 pathway are largely unknown. OS-induced retinal pigment epithelial cell (RPE) damage causes both the initial pathogenesis of AMD and secondary degeneration of rods and cones. Healthy RPE is essential for ocular immune privilege, however, damaged RPE cells can activate inflammatory response. In the present study, we identified IL17RA, the principle receptor of IL17 signaling, is one of the most upregulated inflammatory genes in human RPE cells upon OS exposure. The prominent increase of IL17RA was also observed in RPE and retina of an AMD-like mouse model. Knockdown of IL17RA in RPE cells prevented OS-induced RPE cell apoptosis and reduced the inflammatory response in both RPE and macrophages. Furthermore, we found that transcription factor KLF4 directly activates IL17RA expression, therefore, promotes the production of IL1 beta and IL8 in an IL17RA-dependent manner. In addition, the mRNA level of KLF4 isoform 2 was positively correlated with that of IL17RA in AMD patients. Together, our study demonstrates an unrevealed relationship between IL17RA and OS, and a new regulatory mechanism of IL17RA by KLF4 in RPE cells. These findings suggest that inhibition of IL17RA as a new potential therapeutic target for AMD through RPE protection and inflammatory suppression upon OS exposure.

Background: Paclitaxel (PTX) resistance is a major obstacle in the treatment of triple-negative breast cancer (TNBC). Previously, we have reported that interleukin-1 receptor-associated kinase 1 (IRAK1) and its downstream pathways are associated with PTX resistance in TNBC cells. In this study, we sought to investigate the combination treatment of ginsenoside panaxatriol (GPT), one of the main active components in Panax ginseng, with PTX on viability and apoptosis of TNBC PTX resistant cells, and explore the role of IRAK1 mediated signaling pathways in the therapeutic effects. Methods: CellTiter-Glo and colony formation assays were used to assess cell viability. Flow cytometry was used to analyze subGI and apoptosis. Western blot was used to detect expressions of proteins involved in apoptosis and the IRAK1/NF-kappa B and ERK pathways. The mRNA expression of inflammatory cytokines, S100A7/8/9 and cancer stem cell (CSC)-related genes were examined by qPCR. Stem cells were identified by tumor sphere assay. Cell invasion ability was examined by transwell assay. Results: We show that GPT inhibits MDA-MB-231 PTX resistant (MB231-PR) cell viability in a dose-dependent manner. When combined with PTX, GPT synergistically causes more cell death, induces subG1 accumulation and cell apoptosis. Besides, up-regulation of BAX/BCL-2 ratio, and down-regulation of MCL-1 are also observed. Moreover, this combination inhibits IRAK1, NF-kappa B and ERK1/2 activation, and leads to down-regulation of inflammatory cytokines (IL6, IL8, CXCL1, CCL2), S100A7/9 and CSC-related genes (OCT4, SOX2, NANOG, ALDH1, CD44) expression. In addition, the combination treatment suppresses MB231-PR cell invasion ability, and impairs tumor sphere growth both in MB231-PR and SUM159 PTX resistant (SUM159-PR) cells. Conclusion: Our study demonstrates that GPT can resensitize TNBC PTX resistant cells to PTX by inhibiting the IRAK1/NF-kappa B and ERK pathways and reducing stem cell characteristics.