Differential Expression Of CX MRNA In Endometrial Adenocarcinoma

BackgroundCONNEXIN (Cx) PROTEINS are the major, if not only, component of gap junctions. So far, about 20 family members of Cx proteins have been identified ranging in size from 26 - 56 kDa identified from genomic sequences [1].These Cxs are differentially expressed in a variety of tissues, which is generally believed to reflect cell-specific regulation of gap junctional coupling and functional demands for gap junctions in different cell types. Cx43 is the most widely expressed Cx [2] and has been the subject of intense investigation because its expression is frequently decreased or aberrantly expressed in a variety of pathological conditions, including cancer.The main Cxs expressed in endometrium are Cx43 and Cx26, with the major Cxs expressed in endometrial stromal and epithelial cells being Cx43 and Cx26, respectively [3]. Recent studies have suggested that gap junction protein in endometrial stromal cells play a regulatory role in maintaining normal levels of GJIC in the epithelial cells [4]。Direct cell-cell communication mediated by Cxs has been implicated in coordinating proliferation and differentiation processes, probably mediated through exchange of second messengers such as cAMP and inositol 1,4,5-triphosphate, as well as Ca2+ [5,6]. Correspondingly, loss of cell-cell communication through inappropriate expression of Cxs may be responsible for differentiation processes leading to tumorigenesis.Some reports suggest that Cx plays a key role in the maintenance of normal human endometrium and that its aberrant expression may be involved in the development or progression of endometriosis. Taken together, these reports suggest the possibility that pharmacological manipulation of CX expression may have therapeutic potential in some disease states.MethodsThe expression of CX mRNA was studied by reverse transcription-polymerase chain reaction(RT-PCR).The total RNA of normal endometrium from 23 patients and endometrial carcinoma from 26 patients were extracted using TRI-reagent (Sigma Chemical Co.) following the provider's protocol. Total RNA extracted were frozen at - 80℃ until analyzed. cDNA was synthesized from mRNA samples and subsequently used as template for conventional and PCR assays.CX and its internal control β-actin were co-amplified in the same tube.Semi-quantitative analysis of the mRNA expression level of CX was carried out based on the ratios of the grey scale of the amplified target band to that of the controlband(CX/β-actin). Analysis of amplicons was visualized on 1% agarose gel containing 0.2 μg/μl ethidium bromide. A 100-bp ladder (Promega, Madison, WI) was used as a size standard. Primers for amplifications were made by Sigma-Genosys.ConclusionThe main Cxs expressed in endometrium are Cx43 and Cx26, which expression is frequently decreased or aberrantly expressed in endometrial carcinoma. Cx plays a key role in the maintenance of normal human endometrium and that its aberrant expression may be involved in the development or progression of endometrial adenocarcinoma.