Expression Of BCSG1 In Esophageal Carcinoma And Effects On Invasion Of The Cell Lines

Objective: BCSG1 ( breast cancer specific gene1 )was identified and cloned by direct differential cDNA sequencing in 1997.BCSG1 was previously considered breast cancer specific and was named as breast cancer specific gene 1 (BCSG1) due to its high expression in invasive breast carcinoma,while nearly no positive expressin in normal breast or benign lesions,and its shown ability in inducing breast cancer cells to proliferate and metastasis. BCSG1 is abnormally expressed in tumor tissues of diversified cancer types,including liver, esophagus, colon, gastric, lung, prostate, cervical, and breast cancer.Expressions of BCSG1 protein in different cancer types all display stage-specific patterns of very low expression in stage I and high expression in stages II to IV. Studies confirmed BCSG1 is a tumor marker of malignant progression . As we all know,Hebei Province is the high incidence area of esophageal carcinoma.In this study,we focused on the expression of BCSG1 in esophageal carcinoma samples.And analyze The correlation between BCSG1 protein expression status and clinicopathologic paramenters of patients with esophageal carcinoma.Then transfected this gene into the esophageal cell showed low level of BCSG1 expression and investigated the phenotypic alterations of these cells.To explore biological function and mechanism of BCSG1 in the progressi- on of esophageal carcinoma.Methods1,SP immunohistochemical staining was used to examine the expression of BCSG1 in 30 esophageal carcinoma specimens,randomly selected from Hebei Medical University. T- he patients were include male 22, female8; aged 32to70(mean years59). All cases were confirmed by pathology.There were 7 specimens in gradeⅠ,13 in gradeⅡand 10 in gradeⅢ.Four clinical stages were determined by TNM: 5 specimens in stageⅠ,4 in stagesⅡ, 12 in stageⅢ,and 9 in stageⅣ.All patients didn't have chemotherapy or radiotherapy before operation.Data collected was analyzed by SPSS13.0.A statistically significant difference was indicated by P<0.05.Enumeration date was analyzed by chisquare test.2,Four esophageal cell lines were culurted : Eca-109,TE1,TE10,KYSE450,and the expression levels of BCSG1 mRNA in these four cell lines were detected by RT-PCR.The cell that had low level of BCSG1 mRNA was selected.3,The cell that had low level of BCSG1 mRNA was selected for transfecting into the plasmid containing BCSG1 cDNA and developed the BCSG1 over-expressing cell lines. Reverse transcription polymerase chain reaction(RT-PCR)was performed to evaluate the BCSG1 mRNA expression level . Flow cytometry was used to detect the changes of BCSG1 protein expression level. Transwell in-vitro invasion assays was made to detect the invasive ability of cells.Results1,The positive expression of BCSG1 was 83.3%.There was a positive correlation between the expression of BCSG1 and lymph node metastasis, clinical stage(P<0.05),but there wasn't any significant correlation between the expression of BCSG1 and histological grade, histopathological types,gender,age of the patients(P>0.05). It seems with the reduction of differentiation,BCSG1 protiein expression status increased.2,BCSG1 mRNA was found in four esophageal cell lines ,and Eca-109 expression is lowest .3,Eca-109 was transfected with the plasmid containing BCSG1 cDNA. RT-PCR showed the expression level of BCSG1 mRNA increased significantly compared with the other two groups (P<0.05). Flow cytometry showed the expression level of BCSG1 protein increased significantly compared with the other two groups (P<0.05). The abilities of in vitro invasion through matrigel(167.3±2.51) were significantly increased compared with those in empty plasmid group(65±2.65)and control group(70±2.52) (P<0.01).There wasn't any significant correlati- on between empty plasmid group and control group(P>0.05).Conclusions1,Over一expression of BCSG1 is detected in esophageal cancer tissues and correlates with the lymph node metastasis, clinical stage. It seems with the reduction of differentiation,BCSG1 protiein expression status increased.It may be considered as candidate molecular parameter indicating the invasion and prognosis of esophageal carcinoma.2,BCSG1 mRNA was found in four cell lines. Eca-109 had the lowest level of BCSG1 mRNA while KYSE450 had the highest level.3,Up-regulation of BCSG1 in esophageal cell line could increase the abilities in vitro invasion. BCSG1 may contribute to invasive growth and metastasis of human esophageal cancer through an unknown molecular pathway that promoting cell invasive ability.