Bmi-1 gene is upregulated in early-stage hepatocellular carcinoma and correlates with ATP-binding cassette transporter B1 expression

Kathryn Effendi, Taisuke Mori, Mina Komuta, Yohei Masugi, Wenlin Du, Michiie Sakamoto

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)

Abstract

Overexpression of " stemness gene" Bmi-1 has been identified in some solid tumors. We investigated Bmi-1 expression in hepatocellular carcinoma (HCC) and ATP-binding cassette transporter B1 (ABCB1) as a new potential target for Bmi-1. Bmi-1 was highly expressed in HCC cell lines and the most well differentiated cell line, KIM-1, showed the highest expression. Immunohistochemical, immunocytochemical, and immunoelectron microscopic analysis showed the Bmi-1 protein as having a high intensity of small dots within the nucleus which reflected concentrated sites of Bmi-1 repressive activity. Clear " dot-pattern" staining was observed in 24 of 37 (65%) well differentiated HCC (including 13 of 21 early nodules [62%]), in 32 of 71 (45%) moderately differentiated HCC, and 7 of 14 (50%) poorly differentiated HCC. A similar expression was not observed in non-cancerous background regions. High Bmi-1 expression was observed in the early and well differentiated HCC. Furthermore, overexpression and suppression of Bmi-1 was followed by a respective increase and decrease in ABCB1 expression. As with Bmi-1, high ABCB1 expression was also observed in the early and well differentiated HCC. A strong correlation between ABCB1 and Bmi-1 mRNA expression was seen in HCC cell lines and clinical samples (Pearson's correlation coefficient 0.95 and 0.90, respectively). The Bmi-1 gene is upregulated in HCC, and in particular is highly expressed in early and well differentiated HCC. The fact that this expression correlated with that of ABCB1 suggests a new regulation target for Bmi-1, and gives new insight into early hepatocarcinogenesis mechanisms and potential targets for future HCC treatment.

Original languageEnglish
Pages (from-to)666-672
Number of pages7
JournalCancer science
Volume101
Issue number3
DOIs
Publication statusPublished - 2010 Mar

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

Fingerprint Dive into the research topics of 'Bmi-1 gene is upregulated in early-stage hepatocellular carcinoma and correlates with ATP-binding cassette transporter B1 expression'. Together they form a unique fingerprint.

Cite this