期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2003
卷号：100
期号：24
页码：13988-13993
DOI：10.1073/pnas.2335921100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Previously, we have shown that a strong correlation exists between the metastatic potential of breast carcinoma cell lines and their ectopic expression of IL-8. The undifferentiated, highly metastatic cell lines with high metastatic potential produce much more IL-8 than their differentiated lower metastatic counterparts. After eliminating the possibility that transcription factor activity was responsible for differences in IL-8 release, we examined the IL-8 gene for possible epigenetic modifications. Here, we report an aberrant methylation pattern that may be responsible for the differences in IL-8 release between the high and low metastatic cell lines. We determined that none of the deoxycytidylate-phosphate-deoxyguanylate (CpG) sites in the reported IL-8 promoter were methylated in either cell type. Much further upstream in the IL-8 gene, two CpG sites were identified that are differentially methylated. These two sites were fully methylated in the high metastatic cell lines, which produce large quantities of IL-8 and remain unmethylated in the low metastatic cell lines where the IL-8 gene is relatively silent. The DNA methylation results presented here differ from the common epigenetic paradigm in which methylation of promoter CpG islands silences gene expression, suggesting that there are additional epigenetic control mechanisms that as yet have not been fully appreciated or explored.
