The Expression of Heat Shock Protein 60 kDa in Tissues and Cell Lines of Breast Cancer / 한국유방암학회지

ABSTRACT

PURPOSE: Breast cancer has been reported as the most common cancer of women in the United States, Western Europe and Korea and about 210,000 and 10,000 women in United States and Korea every year, respectively are diagnosed with it. Breast cancer is curable with an early diagnosis, and many researchers have made efforts to find a marker for this malady, heat shock protein (HSP) consists of 6 groups, it is highly preserved throughout both the prokaryotic and eukaryotic cells and it acts as a molecular chaperone that's involved in protein folding. HSPs have been recently reported to be related with breast cancer. In this study, we investigated the changes of expression of HSP60 in tissues and cell lines of breast cancer. METHODS: We obtained breast cancer tissues and normal tissues from breast cancer patients, and we purchased several cancer cell lines from American tissue culture correction. We treated the tissues and the cell lines of human breast cancer with heat shock protein. Proteins and mRNAs were isolated from the tissues and the cells and then we performed Western blotting, reverse transcriptase-Polymerase chain Reaction and fluorescence activated cell sorter analysis on them. RESULTS: On Western blot, HSP60 was more overexpressed in the tissues and the cell lines of breast cancer than in the normal breast tissues and cell lines. The expression of HSP60 showed 2 types of molecular weight differences in the tissues and cell lines of breast cancer, and specifically, low HSP60 was over-expressed in the cancer tissues. There was no difference between the breast cancer cell lines and the normal cell lines in the expressions of HSP60 mRNA, according to the treatment with heat shock. Also, there was no relationship between phosphorylation and the structural difference of HSP60 protein, according to HSP60 protein's molecular weight. The expression of HSP60 has been mostly reported at the mitochondria; however, in this study, it was more predominantly detected at the cytoplasm than at the mitochondria in the breast cancer cell lines. CONCLUSION: We conclude that HSP60 may be used as a diagnostic marker for breast cancer. Detailed investigation of the usefulness and significance of the HSP60 expression as a prognostic factor is required in further studies.