Mechanistic study of cancer-associated ifbroblast senescence and cervical cancer cell invasiveness and radio-resistance conferred by IL-6 through activation of STAT3 and Notch signaling / 中国癌症杂志

Background and purpose:Senescent cancer-associated ifbroblasts (CAFs) in tumor microenvi-ronment are known to mediate the invasion and radio- or chemo-resistance of epithelial cancers. The inflammatory cytokine IL-6 derived from CAFs may promote the invasion and radio-resistance of epithelial cervical cancer. However, the detailed mechanism is not clear. This study aimed to investigate the effects of IL-6 on CAFs senescence, cervical cancer cell invasiveness and radio-resistance.Methods:CAFs from cervical cancer, normal ifbroblasts (NFs) from nor-mal cervical tissues, and cervical cancer cell lines including HeLa, Siha and ME180 were used in this study. Different treatments of cells with IL-6 and inhibitors of STAT3 and Notch were conducted to investigate the alterations of cellular senescence, STAT3/Notch signaling, cell invasiveness, and radiotherapy-induced apoptosis by using cell staining, immunolfuorescence, Western blot, and lfow cytometery.Results:This study found that the conditioned medium (CM) of CAFs or IL-6 could activate the STAT3 and Notch signaling to promote cellular senescence and cervical cancer cell invasiveness. Co-culture of cervical cancer cells HeLa or Siha along with CAFs also increased the invasiveness of can-cer cells, but further treatments of cells by addition of an IL-6 antibody or the inhibitors of STAT3 (S31-201) or Notch (DAPT) blocked the cancer cell invasion. Meanwhile, this study also found that STAT3 functions at the upstream of the Notch signaling to up-regulate Jagged-1, one of the key ligands of Notch in ifbroblasts or epithelial cancer cells through IL-6-mediated autocrine or paracrine pathways, which eventually confers the radio-resistance of cervical cancer cells/tissues.Conclusion:CAFs in tumor microenvironment could induce cervical cancer cell invasiveness and radio-re-sistance through IL-6/STAT3-mediated Notch activation, and that targeting of the STAT3/Notch signaling-associated molecules may improve the effcacy of radiotherapy for cervical cancer.

Eukaryotic expression of human NOVA1 protein and identification of its anti-hypoxia activity / 生物工程学报

The aim of this study was to construct the eukaryotic expression vector of pCMV-Myc-NOVA1 based on NOVA1 gene, and to screen the optimum expression condition after transfecting to PC12 cells, and further to explore the distribution of NOVA1 protein in PC12 cells using cell immunohistochemistry, and to identifyits anti-hypoxia activity. According to the NOVA1 gene sequence of NCBI database, we designed the upstream and downstream primers, and performed polymerase chain reaction (PCR) to amplify the full length cDNA coding sequence using pCR4-TOPO-NOVA1 as a template. The products were digested by restriction endonuclease SalⅠand XhoⅠ, and conjugated to the eukaryotic expression vector ofpCMV-Myc followed by validating by digestion and direct sequencing. Subsequently, the validated pCMV-Myc-NOVA1 was transfected to PC12 cells followed by optimizing of transfection ratio and transfection time, and identified by qPCR, Western blotting and cell immunohistochemistry respectively. After validation by digestion and direct sequencing, the eukaryotic expression vector of pCMV-Myc-NOVA1 was correctly constructed. The optimum transfection ratio of plasmid to Lipo 2000 was 1:2.5, and the optimum transfection time was 72 h. At the optimum transfection condition, the expression level of NOVA1 mRNA and protein significantly increased, and after transfection of pCMV-Myc-NOVA1, NOVA1 protein mainly distributed in cell nucleus and cytoplasm. After 6 h hypoxia, the cell proliferation activity was significantly increased compared to that of the control and pCMV-Myc group. Our findings provided a reference for exploring the mechanism of NOVA1, and also a technical support for potential drug development of NOVA1.

Cancer-associated fibroblasts promotes migration and invasion of cervical epithelial cancer cells through IL-6-induced “epithelial-mesenchymal” transition / 中国癌症杂志

Background and purpose: Cancer-associated fibroblasts (CAFs) are known to promote the invasion and metastasis of epithelial cancers. The cytokine IL-6 may mediate the interaction between stromal cells and epithelia in tumor microenvironment to facilitate the invasiveness and metastasis of cancer, however, such mechanism has not been fully covered yet.Methods:We used cervical cancer cell line HeLa as a model for this study. ELISA was used to measure the levels of IL-6 in CAFs and normal ifbroblasts (NFs) isolated from squamous cervical cancer or normal cervical tissues. CAFs conditioned medium or IL-6 was used to treat cervical cancer HeLa cell line. The epithelial-mesenchymal transition (EMT) markers such as N-Cadherin and Vimentin were detected by Western blot in cells before and after treatment. Scratches and transwell chambers were used to test the abilities of cell migration and invasion. Results:The levels of IL-6 were 4-5 folds higher in CAFs than in NFs. Treatment of HeLa cells with CAF conditioned medium or IL-6 upregulated N-Cadherin and Vimentin, but down-regulated E-Cadherin and cytokeratin, compared with control cells, indicating that IL-6 may stimulate HeLa cells to EMT. Further study found that Snail 1, the featured transcription factor for stem cells, was increased along with the enhanced phosphorylation of STAT3. Meanwhile, the migration and invasion of HeLa cells treated with IL-6 or CAF conditioned medium were markedly increased. Conclusion:CAF induces the EMT of cervical epithelial cancer cells through IL-6/STAT3/Snail pathway, which thereby promotes the invasiveness and metastasis cervical epithelial cancer.

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

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.