Promotion of ovarian tumorigenesis by cancer-associated ifbroblasts through Gro-αactivated NF-кB nuclear translocation and high expression of VEGF / 中国癌症杂志

ABSTRACT

Background and purpose:Ovarian cancer-associated ifbroblasts (CAF) are known to promote epithelial malignancy. The chemoattractant cytokine growth-regulated oncogene alpha (Gro-α) secreted from CAF has been reported to mediate the stroma-epithelia interaction in tumor microenvironment, leading to the development of epithelial ovarian cancer, however, the detailed mechanism is unknown.This study was to determine whether Gro-αcould promote ovarian tumorigenesis through activating NF-кB nuclear translocation and VEGF expression in stromal ifbroblasts. Methods:ELISA was used to measure the levels of Gro-αin two cancer-associated ifbroblasts (CAF) and normal ifbroblasts (NF) isolated from high-grade serous ovarian cancer or normal ovarian tissues. CAF conditioned medium (CM) or Gro-αwas used to treat NF, while PS1145, the inhibitor of NF-кB, was used as control. NF-кB subunit p65 and vascular endothelial growth factor (VEGF) were detected by Western blot in cells after treatment. Xenograft tumors from nude mice were generated by injection of CAF, NF, or OVCA429 alone or OVCA429 mixed with CAF or NF, and by injection of OVCA429 mixed with NF cells that were treated with or without CAF-CM or Gro-α, or with NF cells that were treated with CAF-CM or Gro-αplus PS1145. The tumor growth curve was measured and the blood vessel density in xenograft tumor tissues was examined by histopathological analysis. Results:The levels of Gro-αwere 5-6 folds higher in CAF than in NF. Treatment of NF with CAF-CM or Gro-αstimulated the nuclear translocation of NF-кB subunit p65, and the expression of VEGF, but suppressed the expression of thrombospondin 1, the anti-angiogenesis factor, compared with control cells. However, treatment of NF with the NF-кB inhibitor PS1145 reversed these results. The animal assay revealed that CAF stimulated tumor growth stronger than NF, and NF treated with CAF-CM or Gro-α, but not along with PS1145, enhanced xenograft tumor growth through promoting angiogenesis. Conclusion:Ovarian CAF promotes the nuclear translocation of NF-кB and the expression of VEGF through Gro-αautocrine in tumor microenvironment to facilitate angiogenesis and ovarian cancer development.