STC2 Regulates Radiation Resistance And Mechanism Of Cervical Cancer Cells

Cervical cancer is one of the most common cancers in the female reproductive system,and women's quality of life is seriously affected as a result [1].Previous research has confirmed that persistent high-risk human papillomavirus(HPV)infection is a prerequisite for the development and development of cervical cancer [2].The usual treatments for cervical cancer are surgery,radiotherapy,chemotherapy and molecular targeted therapy [3].Radiation therapy remains the main treatment,especially in advanced cervical cancer [4].To date,nearly 70% of cancer patients have used radiation therapy to treat tumors,which is considered the standard treatment for locally advanced cervical cancer.However,many factors influence the prognosis of radiotherapy.Many recent studies have found that STC 2 gene is a target gene of hypoxia-inducible factor 1(HIF-1),which can promote the proliferation,invasion,migration and epithelial-mesenchymal transition during hypoxia [5].STC2 associated with breast cancer,ovarian cancer,renal cell carcinoma,prostate cancer,and neuroblastoma [6-8].It is clear that overexpression of STC2 in cancer tissues is associated with cancer development and poor prognosis.In this study,we examined the expression pattern of STC2 in cervical cancer specimens and cell lines,and analyzed the potential correlation between STC2 and cervical cancer.In addition,we tested its effects on cell proliferation and migration,and investigated the potential effects of STC2 on cervical cancer cell cycle changes.Finally,we explored the underlying mechanism of STC2 function in cervical cancer.Therefore,These data strongly suggest that STC2 may be a new target for cancer therapy.Background:STC2 is a member of the cascadine family,encoding a 302 amino acid protein and has a high degree of sequence homology with STC1.Although 4.4 kb transcripts were also detected in some tissues,STC2 was mainly expressed as 2 kb transcripts.STC2 has been found in many physiological processes such as bone development,reproduction,wound healing,angiogenesis and mod?lation of the inflammatory response [9].However,previous studies have also shown that STC2 is upregulated in human gastric cancer,neuroblastoma,breast cancer,colorectal cancer,and renal cell carcinoma [10-11].For example,it accelerates the invasion and metastasis of tumor cells,and inhibits apoptosis [12].Under various stress conditions,including hypoxia and radiation,the expression of stanniocalcin 2(STC2)was up-regulated,thereby promoting tumor cell proliferation,invasion and migration.It is clear that overexpression of STC2 in cancer tissues is associated with cancer development and poor prognosis.However,the role of STC2 is unclear in cervical cancer.Purposes:1.To elucidate the mechanism and signaling pathways of stanniocalcin(STC2)in regulating the radiation sensitivity of cervical cancer tumor cells2.To elucidate that STC2 regulates a series of biological functions in cervical cancer caused by ionizing radiation.3.To clarify the effect of STC2 expression on the prognosis of cervical cancer after radiotherapy.Methods:1.Real-time quantitative PCR was used to detect the expression levels of STC2 gene in five cervical cancer cell lines after 8 Gy X-ray irradiation;2.Construct and verify the recombinant plasmid STC2 overexpression plasmid and SiSTC2 silencing plasmid;3.Transient transfection was used to transfect the plasmid into cervical cancer cells,and real-time quantitative PCR and Western Blot were used to verify the transfection efficiency;4.Transfect STC2 overexpression plasmid or SiSTC2 silencing plasmid,and use RT-PCR and Western Blot to detect the expression levels of STC2 mRNA and protein in cervical cancer after irradiation;5.The experimental method of CCK8 was used to detect the effect of overexpression of STC2 on the survival rate of cervical cancer cells after irradiation;6.After overexpression of STC2,detect the migration and invasion of cervical cancer cells;7.After over-expressing STC2,use flow cytometry to detect apoptosis levels and cycle changes induced by ionizing radiation;8.Using a clone formation experiment to detect the effect of silenced STC2 on the ability of irradiated cells to form clones;9.After the silence of STC2,detect the migration and invasion of cervical cancer cells;10.After silencing STC2,use flow cytometry to analyze changes in the period and apoptosis induced by ionizing radiation;11.Western Blot was used to detect the effect of STC2 protein expression on cervical cancer-related protein expression after irradiation.Results:1.Different expression levels of STC2 in different cervical cancer cellsCervical cancer cell lines(Hela,SiHa,ME-180,C-33 A,Caski)have different background expressions of STC2.According to our experimental purpose,SiHa and ME-180 were selected as experimental cell lines.2.Radiation-induced STC2 transcription and protein levelssiSTC2 can inhibit the STC2 transcription and translation level of cervical cancer cells after irradiation,and transfection of STC2 overexpression plasmid can up-reg?late the expression of STC2 protein after irradiation.3.STC2 overexpression enhances radiation resistance of cervical cancer cellsConstruction of STC2 overexpression plasmid.The levels of STC2 mRNA in SiHa and ME-180 cells transfected with the STC2 overexpression plasmid significantly increased(p<0.05).After 8 Gy irradiation,transfection of the STC2 overexpression plasmid significantly increased the STC2 mRNA in cells(p<0.05)).After 8Gy irradiation,the apoptotic rate of cells transiently transfected with STC2 over-expressing plasmid decreased(p<0.05),G2/M cell arrest was down-reg?lated(p<0.05),enhanced cell migration and invasion.4.Silencing STC2 enhances radiation sensitivity of cervical cancer cell linesTransfection of SiSTC2 can silence STC2 mRNA and protein expression of cervical cancer cells.After STC2 was silenced,the cell proliferation rate decreased.Silencing STC2 significantly reduced the number of clones formed in SiHa and ME-180 cells(p<0.05).24 hours after X-ray irradiation with 8Gy,SiSTC2 can increase the early apoptosis rate of cells(p<0.05)and increase cell block in G2 / M phase.After 8Gy irradiation,the migration and invasion ability of silenced STC2 cells was significantly reduced(p<0.05).Conclusions:These data indicate that STC2 expression is an important factor in promoting survival and metastasis of cervical cancer cells after radiation,and STC2 can reg?late radiation resistance of cervical cancer.Therefore,targeting STC2 or its upstream and downstream may provide novel therapeutic regimens.