ABSTRACT
Background and purpose:Most breast cancer cell lines were derived from malignant pleural fluid or other tissues that metastasized from breast carcinoma.Breast carcinogenesis is under represented due to the significant distinction of biological characteristics between cancer cell lines and primary breast cancers.Few primary breast tumors spontaneously developed into immortal cell lines.Overexpression of human telomerase reverse transcriptase(hTERT) in normal epithelial cells led to immortalization.We aimed to establish immortalized cultures derived from primary breast cancer by introducing hTERT and determine the gene profile of hTERT-transfected cultures.Methods:hTERT was introduced into breast tumor cultures with a puromycin-resistant retroviral construct,pBABE-hTERT-puro.Real-Time RT-PCR was used to analyze the expression level of hTERT after transfection.The upregulated gene profile was determined with microarray techniques.Results:hTERT was stably over expressed,at least 1 400-fold in hTERT-transfected cells compared to pBABE-puro transfected cultures.These ectopic over-expressions led to immortalization of transfected cultures,which could undergo at least 40-50 passages.Microarray analysis further confirmed the over-expression of hTERT in transfected cultures and demonstrated that 22 genes were up-regulated due to over-expression of hTERT.No down-regulated genes were observed cross all cultures.Conclusions:Over-expression of hTERT led to immortalization of breast tumor primary cultures and up-regulated certain genes.