The Research Of Expression And Molecular Mechanism Of HOXB7 In Intrahepatic Cholangiocarcinoma

Aims:Intrahepatic Cholangiocarcinoma(ICC)is an epithelial cell malignancy that can originate in different locations of the biliary tree and the second most common primary hepatic neoplasm after hepatocellular carcinoma.Although ICC is relatively rare,its incidence is increasing.ICC is one of the most deadly cancers.Therefore,it is particularly important to find new prognostic markers and new therapeutic targets to improve the ICC diagnosis rate and therapeutic effect.HOXB7 can drive transcription of downstream targets directly and play an important role in a variety of cellular processes.Meanwhile,it has been reported to be abnormally expressed in a variety of tumors.However,the expression and specific biological functions of HOXB7 in ICC have not been well characterized.Hence,our study will focus on the expression profile,biological functions and the specific molecular mechanisms of HOXB7 to improve the prognosis of ICC patients.Methods:Firstly,we collected tumor samples and adjacent normal tissue samples from ICC patients and detected the expression of HOXB7 by real-time PCR,western blotting and immunohistochemistry.Then overall survival time and prognosis was assessed by statistical analyses of HOXB7 expression and clinicopathological parameters.Next,we constructed a stable ICC cell line overexpressing HOXB7 using the lentiviral.The role of HOXB7 was studied in vitro via CCK-8 counting,colony formation,capillary tube formation,transwell and cell cycle analysis.Furthermore,the role of HOXB7 in ICC was clarified by nude mice xenograft assay and tail vein metastatic assay in vivo.We also studied the biological functions of HOXB7 by transfecting with siRNA.Then,we used western blotting to find downstream molecules regulated by HOXB7.Also,knocking down of IL8 and blocking ERK pathway were used to carry on the rescue experiments in vitro to explore the specific molecular mechanisms.Results:We found that HOXB7 expression was significantly upregulated in ICC tumors.ICC patients with high expression of HOXB7 have a poor prognosis.Moreover,overexpression of HOXB7 promoted ICC metastasis by increasing the expression of MMP2 and MMP9;promoted ICC angiogenesis by increasing the expression of IL8 and VEGFa.In contrast,knocked down of HOXB7 showed the opposite result in vitro.Surprisingly,HOXB7 had no effect on ICC proliferation in vitro,but could promote ICC proliferation in vivo.Knocked down of IL8 and using ERK inhibitor blocked the effects of HOXB7 and changed the expression of downstream targets as MMP2,MMP9,IL8 and VEGFa.Conclusions:Our study confirmed a significant association between HOXB7 expression and poor prognosis in ICC patients.Furthermore,our results revealed a mechanism by which HOXB7 may promote ICC angiogenesis and metastasis:by activating the ERK pathway to regulate the expression of MMP2,MMP9,IL8 and VEGFa.Therefore,HOXB7 expression may be a valuable prognostic indicator for ICC patients,and it may become a new molecular marker for ICC diagnosis,prognosis and early warning in the future,and provide a potential target for the treatment of ICC.