Establishment And Application Of Patient-derived-tumor-orthotopic Xenograft Model Of Oral Mucosal Melanoma

Purpose:Oral mucosal melanoma is a highly aggressive malignant carcinoma,with relatively high incidence of local lymph node and distant metastasis.The 5-years-survival is extremely poorer than any other carcinoma,especially those metastatic melanoma has a median survival time of shorter than 10 months and 5-years-survival rate lower than10%.Though conventional treatment like surgery radio(chemo)-therapy and multiple discipline treatment continuously accelerated the expansion of prognosis of carcinoma patient,it is essentially palliative with OMM.However mucosal melanoma-specific treatment is still deficient even empty,it is typically urgent that develop an appropriately precise and clinical effective regime.Vasculogenic mimicry is a formation of vascular–like structure which is made up with tumor cell rather than endothelial cell,providing the tumor with blood and nutrition as well as potential target chance.Besides,it is related with the malignant population and poor clinical outcome.Therefore we compare different ways to establish the patient-derived orthotopic xenograft model of oral mucosal melanoma,then identify the best way to establish PDOX model to further the research of tumor biology,target medicine development,clinical strategies optimization and so on.Meanwhile we use PDOX model to validate the effect of axitinib on OMM and identify the mechanism of hampering the formation of VM.Methods:1.Through surgical orthotopic implantation of tumor specimens to establish the PDOX model,then compare the model with the group that relys on PDC which cultivate from tumor specimens as well as PDX groups in the view of histological feature,vasculogenic mimicry and protein expression.2.After we successfully established several OMM-bearing PDX and PDOX models,nude mice were randomly divided into the CMC group and the axitinib group(axitinib 100mg/kg*day).The mice were assessed for histological and molecular features by immunochemical assay as well as growth status at least twice a week using vernier caliper.VM was evaluated by immunochemistry and periodic acid schiff reaction(PAS)histochemical double-staining.Result:1.The PDC which cultivated from tumor specimens is validated by IF and subcutaneously injected into nude mice.The newly-form tumor was assured as OMM by IHC.The histological and molecular property of all three successful models is consistent with that of primary mucosal melanoma.The group that surgically implants tumor specimens into cheek pouches.2.The tumor volume and the number of vasculogenic mimicry in the axitinib group was markedly lower than the control one.Distinct from CMC group,the number of CD34-positive vessels and metastasis rate obviously decreased after oral administration.H&E staining showed that tumor after treatment with axitinib were characterized by obvious necrosis,but none in the control group.Meanwhile,relative to control group we found that the protein level of MMP-2 as well as Eph2 A was significant decreased in the axitinib group,meanwhile the expression of HIF1 a was increased.Conclusion:The model established by injecting into cheek pouches with tumor specimens could be a desirable animal model to study mucosal melanoma.Axitinib could inhibit oral mucosal melanoma growth in PDX and PDOX models,which may result from hampering the vasculogenic mimicry channels formation which related with the VEGF-A/VEGFR signaling.