Enhanced coexpression of YB-1 and DNA topoisomerase II α genes in human colorectal carcinomas

Kazunori Shibao, Hiroshi Takano, Yoshifumi Nakayama, Keisuke Okazaki, Naoki Nagata, Hiroto Izumi, Takeshi Uchiumi, Michihiko Kuwano, Kimitoshi Kohno, Hideaki Itoh

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129 Citations (Scopus)


The transcription factor YB-1 is expressed in a wide range of cell types and has been implicated in the regulation of various genes involved in cell proliferation. Nuclear expression of YB-1 is correlated with MDR-1 gene expression in breast cancer and osteosarcoma. In this study, we asked whether YB-1 expression is enhanced in human colorectral carcinoma and if it is associated with the expression of target genes such as MDR-1, DNA topoisomerase II α and PCNA. YB-1, DNA topoisomerase II α, PCNA and MDR-1 expression were assessed by Western blotting, Northern blotting and immunohistochemistry in 26 human colorectal carcinomas. The involvement of YB-1 in DNA topoisomerase II α gene expression was examined by transient DNA transfection assays. YB-1 was overexpressed in almost all cancerous lesions in comparison with normal mucosa in surgically resected colorectal carcinomas of 26 patients. YB-1 expression correlated well with both DNA topoisomerase II α and PCNA expression. In contrast, no correlation was observed between YB-1 and MDR-1 expression. We also found that a transient co-transfection with a DNA topoisomerase II promoter-luciferase plasmid and an antisense YB-1 expression construct resulted in a significant reduction of the promoter activity in KM12C human colon cancer cells. YB-1 may be an excellent proliferation-associated marker and may be a transcription factor regulating DNA topoisomerase II gene expression in human colorectal carcinoma.

Original languageEnglish
Pages (from-to)732-737
Number of pages6
JournalInternational Journal of Cancer
Issue number6
Publication statusPublished - Jan 1 1999

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research


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