Altered expression of MLL methyltransferase family genes in breast cancer.

Abstract

The histone lysine methyltransferases contain a SET domain, which catalyzes the addition of methyl groups to specific lysine residues. The MLL family of genes encodes histone-modifying enzymes with histone 3-lysine 4 methyltransferase activity that can regulate gene transcription. The MLL family exists in multi-protein complexes and has been implicated in a variety of processes including normal development and cell growth. Although some of the MLL family members have already been described to be involved in cancer, a clear relationship of these genes with breast cancer is not determined to date. In the present study, we used quantitative PCR to investigate the expression profile of all five MLL genes [MLL (ALL-1), MLL2, MLL3, MLL4 and MLL5] in 7 breast cancer cell lines, 8 breast tumors and adjacent non-tumor tissues and in 12 normal tissues. We observed a diminished expression of all five genes in the breast cancer cell lines when compared to normal breast tissue. We found a significantly decreased expression of MLL2 in the tumor samples compared to the non-tumor controls. In tumor samples, MLL5 also showed a clear suppression tendency. Among the normal tissues analyzed, all genes showed a markedly higher expression in skeletal muscle and brain. Although further studies are required to determine the exact role of these methyltransferases in cancer development, our results indicate that the suppression of MLL genes, especially MLL2 and 5, take part in modulating breast carcinogenesis. Our assessment of the MLL family gene expression patterns in a diverse set of breast cancer cell lines and in a multitude of tissue types and breast tumors should lead to increasingly detailed information on the involvement of these genes in cancer progression.

• Authors: Doralina do Amaral Rabello, Carolina Amaro de Moura, Rosangela Vieira de Andrade, Andrea Barretto Motoyama, Fabio Pittella Silva
• Journal: International journal of oncology (Int J Oncol) Vol. 43 Issue 2 Pg. 653-60 (Aug 2013) ISSN: 1791-2423 [Electronic] Greece
• PMID: 23754336 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• DNA-Binding Proteins
• KMT2D protein, human
• KMT2E protein, human
• Neoplasm Proteins
• Methyltransferases

Topics

• Breast Neoplasms (genetics, pathology)
• Carcinogenesis (genetics)
• Cell Line, Tumor
• Cell Proliferation
• DNA-Binding Proteins (genetics)
• Female
• Gene Expression Regulation, Neoplastic
• Humans
• MCF-7 Cells
• Methyltransferases (genetics)
• Neoplasm Proteins (genetics)