ABSTRACT
To identify molecular alterations implicated in the initiating steps of breast tumorogenesis, we compared the gene expression profiles of normal and ductal carcinoma in situ (DCIS) mammary epithelial cells by using serial analysis of gene expression (SAGE). Through the pair-wise comparison of normal and DCIS SAGE libraries, we identified several differentially expressed genes. Here, we report the characterization of one of these genes, HIN-1 (high in normal-1). HIN-1 expression is significantly down regulated in 94% of human breast carcinomas and in 95% of preinvasive lesions, such as ductal and lobular carcinoma in situ. This decrease in HIN-1 expression is accompanied by hypermethylation of its promoter in the majority of breast cancer cell lines (>90%) and primary tumors (74%). HIN-1 is a putative cytokine with no significant homology to known proteins. Reintroduction of HIN-1 into breast cancer cells inhibits cell growth. These results indicate that HIN-1 is a candidate tumor suppressor gene that is inactivated at high frequency in the earliest stages of breast tumorogenesis.
Subject(s)
Breast Neoplasms/metabolism , Breast/metabolism , Carcinoma, Ductal, Breast/metabolism , Carcinoma, Intraductal, Noninfiltrating/metabolism , Carcinoma, Lobular/metabolism , Cytokines/isolation & purification , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Genes, Tumor Suppressor , Neoplasm Proteins/isolation & purification , Tumor Suppressor Proteins , Amino Acid Sequence , Animals , Blotting, Northern , Blotting, Western , Breast/cytology , Breast Neoplasms/genetics , Breast Neoplasms/pathology , CHO Cells , COS Cells , Carcinoma, Ductal, Breast/genetics , Carcinoma, Ductal, Breast/pathology , Carcinoma, Intraductal, Noninfiltrating/genetics , Carcinoma, Intraductal, Noninfiltrating/pathology , Carcinoma, Lobular/genetics , Carcinoma, Lobular/pathology , Cell Division , Cells, Cultured/metabolism , Chlorocebus aethiops , Cricetinae , Cricetulus , Cytokines/biosynthesis , Cytokines/genetics , Cytokines/physiology , DNA Methylation , Epithelial Cells/metabolism , Female , Gene Library , Gene Silencing , Growth Inhibitors/genetics , Growth Inhibitors/physiology , Humans , Molecular Sequence Data , Neoplasm Proteins/biosynthesis , Neoplasm Proteins/genetics , Promoter Regions, Genetic , RNA, Messenger/biosynthesis , RNA, Neoplasm/biosynthesis , Recombinant Fusion Proteins/physiology , Sequence Alignment , Sequence Homology, Amino Acid , Transfection , Tumor Cells, Cultured/metabolismABSTRACT
The development and use of molecular-based therapy for breast cancer and other human malignancies will require a detailed molecular genetic analysis of patient tissues. The recent development of laser capture microdissection and high density cDNA arrays now provides a unique opportunity to generate gene expression profiles of cells from various stages of tumor progression as it occurs in the actual neoplastic tissue milieu. We report the combined use of laser capture microdissection and high-throughput cDNA microarrays to monitor in vivo gene expression levels in purified normal, invasive, and metastatic breast cell populations from a single patient. These in vivo gene expression profiles were verified by real-time quantitative PCR and immunohistochemistry. The combined use of laser capture microdissection and cDNA microarray analysis provides a powerful new approach to elucidate the in vivo molecular events surrounding the development and progression of breast cancer and is generally applicable to the study of malignancy.
