Correlation and prognostic value of osteopontin and Bcl-2 in hepatocellular carcinoma patients after curative resection

Oncol Rep. 2013 Dec;30(6):2795-803. doi: 10.3892/or.2013.2737. Epub 2013 Sep 19.

Abstract

Osteopontin (OPN) may facilitate tumorigenesis and metastasis through prevention of tumor cells from apoptosis. Although previous studies have suggested involvement of enhanced Bcl-2 protein family expression, the role of OPN together with Bcl-2 in hepatocellular carcinoma (HCC) remains unknown. In this study, we used western blotting to detect the OPN and Bcl-2 expression levels in cell lines with different OPN backgrounds and HCC tissues, and tumor tissue microarrays to examine OPN and Bcl-2 expression levels in 454 HCC cases. The Kaplan-Meier method and log-rank test were applied to investigate the predictive values of OPN and Bcl-2 in HCC patients. In vitro assays indicated that OPN expression increased concordantly with increasing metastatic potential in MHCC97-H, MHCC97-L, HepG2 and SMMC-7721 cell lines by western blotting, whereas Bcl-2 expression declined. In addition, Bcl-2 was highly upregulated in OPN knockdown MHCC97-H cell lines. Furthermore, in HCC tissues, it was confirmed that OPN levels were also significantly higher in recurrent tumor tissues compared to non-recurrent tissues by western blotting (p<0.001), whereas the contrary occurred in Bcl-2 (p=0.046). Using immunohistochemistry analysis, patients with higher OPN levels had significantly shorter median survival time and recurrence time compared to the lower ones, although the opposite occurred in Bcl-2 levels. Of note, when OPN and Bcl-2 were combined, we found that the co-index of OPN/Bcl-2 was an independent prognostic factor for both overall survival (p<0.001) and time to recurrence (p<0.001). Our findings demonstrate that OPN/Bcl-2 expression is a promising independent predictor of recurrence and survival in HCC. Additionally, Bcl-2 levels may be regulated by OPN in the HCC microenvironment.

MeSH terms

  • Adult
  • Aged
  • Carcinogenesis
  • Carcinoma, Hepatocellular / genetics*
  • Carcinoma, Hepatocellular / pathology
  • Female
  • Follow-Up Studies
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Kaplan-Meier Estimate
  • Liver Neoplasms / genetics*
  • Liver Neoplasms / pathology
  • Male
  • Middle Aged
  • Neoplasm Metastasis
  • Osteopontin / biosynthesis
  • Osteopontin / genetics*
  • Prognosis*
  • Proto-Oncogene Proteins c-bcl-2 / biosynthesis
  • Proto-Oncogene Proteins c-bcl-2 / genetics*

Substances

  • Proto-Oncogene Proteins c-bcl-2
  • Osteopontin