Expressions Of Multidrug Resistance Proteins In Human Esophageal Squamous Cell Carcinoma And The Role Of GSK-3 Inhibitor In The Signaling Pathway Of It

Objective:To study the change and significance of the expressions of P-catenin, ABC transporter proteins:MRP2, P-gp, anti-apoptosis protein:Bcl-2 and to explore the functions and correlations of the expressions of them, the ATP level, the efflux capability of P-gp, MRP2 in esophageal squamous cell carcinoma (ESCC) cell: EC-109 induced by ATP compective GSK-3 inhibitor:6-bromoindirubin-3'-oxime (BIO) and the influence of BIO to the multidrug restance (MDR) of ESCC cell.Methods:We applied tissue microarray (TMA) technique, immunohistochemistry (IHC) and image analysis method to detect the expressions of MRP2, P-gp, P-catenin and Bcl-2 protein and analyze their relationships with clinical data in a ESCC tissue microarray consisting of 582 specimens of ESCC,294 specimens of normal mucosa, 92 specimens of basal cell hyperplasia and 87 specimens of dysplasia adjacent to cancer tissues. We also applied flow cytometry, immunofluorescence cytochemistry, ATP assay kit method to study the change of the expressions of MRP2, P-gp,β-catenin and Bcl-2, the efflux capability of ABC transporter proteins, and ATP level in ESCC cell:EC-109 induced by BIO.Results:1 The expressions of MRP2 and Bcl-2 were higher in ESCC, dysplasia adjacent to cancer and basal cell hyperplasia than those in normal mucosa (P<0.01). The expressions of P-gp andβ-catenin were lower in ESCC than those in dysplasia adjacent to cancer, basal cell hyperplasia and normal mucosa (P<0.01). In accordance with the following order, well differentiation—moderate differentiation—poor differentiation, the expression of MRP2 increased in ESCC (P<0.01). The expression ofβ-catenin was higher in poor differentiation ESCC than those in well and moderate differentiation ESCC (P<0.01). The expression of Bcl-2 was lower in well differentiation ESCC than those in poor and moderate differentiation ESCC (P<0.01). The positive ratio of the expressions of Bcl-2 andβ-catenin was significantly related with infiltration depth (P<0.01). The IOD of Bcl-2 was significantly higher in the lymph node metastasis (LNM) cases than in the cases without LNM (P<0.01). Positive correlations which were respectively between the expressions of P-gp and MRP2, the expressions of P-gp and Bcl-2 were found (r=0.288 and r=0.253, respectively, P< 0.01).2 After induced by BIO, up regulation of the expressions of P-catenin and Bcl-2 in endochylema and the accumulation ofβ-catenin in nucleus could be found in ESCC cell:EC-109. The expression of MRP2 could be up regulated in endochylema and cytolemma; on the contrary the expression of P-gp was down regulated in endochylema and cytolemma. And the ATP level and the efflux capability of ABC transport proteins to their substrate:Rhodaminel23 increased in ESCC cell.Conclusions:1 MRP2, P-gp, Bcl-2 may be taken as prognosis factors for the MDR of ESCC.2 After induced by ATP compective GSK-3 inhibitor:BIO, up regulation of the expressions ofβ-catenin and Bcl-2 in endochylema and the accumulation of P-catenin in nucleus could be found in ESCC cell:EC-109. This result infers that except the regulation to glycometabolism, GSK-3 can regulate important physiological functions:proliferation, apoptosis, differentiation of cell.β-catenin is a critical member of Wnt pathway and plays an important role in the carcinogenesis and progress of ESCC.3 The efflux capability of ATP energy dependent ABC transport proteins to their substrate:Rhodamine123 and the ATP level in ESCC cell:EC-109 can be up regulated after induced by ATP compective GSK-3 inhibitor:BIO and it infers that there is interaction between the efflux capability of ATP energy dependent ABC transport proteins. It provides new way to understand the mechanisms of ABC transport proteins in the MDR of tumor cell.