OCT4 spliced variant OCT4B1 is expressed in human colorectal cancer

Authors

  • Maria Gazouli,

    Corresponding author
    1. Laboratory of Biology, Department of Basic Medical Sciences, University of Athens School of Medicine and Cell and Gene Therapy Laboratory, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
    • Laboratory of Biology, School of Medicine, University of Athens, Michalakopoulou 176, 11527 Athens, Greece.
    Search for more papers by this author
  • Maria G. Roubelakis,

    1. Laboratory of Biology, Department of Basic Medical Sciences, University of Athens School of Medicine and Cell and Gene Therapy Laboratory, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
    Search for more papers by this author
  • George E. Theodoropoulos,

    1. First Department of Propaedeutic Surgery, University of Athens School of Medicine, Hippocration Hospital, Athens, Greece
    Search for more papers by this author
  • Joanna Papailiou,

    1. First Department of Propaedeutic Surgery, University of Athens School of Medicine, Hippocration Hospital, Athens, Greece
    Search for more papers by this author
  • Anna Vaiopoulou,

    1. Laboratory of Biology, Department of Basic Medical Sciences, University of Athens School of Medicine and Cell and Gene Therapy Laboratory, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
    Search for more papers by this author
  • Kalliopi I. Pappa,

    1. Laboratory of Biology, Department of Basic Medical Sciences, University of Athens School of Medicine and Cell and Gene Therapy Laboratory, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
    2. First Department of Obstetrics and Gynecology, University of Athens School of Medicine, Alexandra University Hospital, Athens, Greece
    Search for more papers by this author
  • Nikolaos Nikiteas,

    1. Second Propaedeutic Department of Surgery, Laikon Hospital, University of Athens School of Medicine, Athens, Greece
    Search for more papers by this author
  • Nicholas P. Anagnou

    1. Laboratory of Biology, Department of Basic Medical Sciences, University of Athens School of Medicine and Cell and Gene Therapy Laboratory, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
    Search for more papers by this author

Abstract

OCT4, a POU-domain transcription factor is considered to be a key factor in maintaining the pluripotency of stem cells. Several OCT4 isoforms are differentially expressed in human pluripotent and non-pluripotent cells. Reactivation of OCT4 expression is postulated to occur in differentiated cells that have undergone tumorigenesis. To examine OCT4 expression in colorectal cancer (CRC) tissues, and to assess the efficacy of OCT4 as a potential biomarker for CRC, in this study, we investigated its expression in CRC tissues, evaluated its relationship to various clinicopathological parameters and defined the isoform of OCT4 that was found to be expressed in CRC cases. Primary tumor tissues and matching adjacent non-cancerous tissues were obtained from 84 CRC patients. OCT4 expression and isoform determination were documented by reverse transcription-PCR and real-time PCR. OCT4, Sox-2, and NANOG localization were performed using immunohistochemistry. The isoforms expressed in the studied cases were confirmed by sequencing. Twenty biopsy specimens representing healthy tissues, retrieved from colonoscopy were studied in parallel as controls. OCT4 expression levels were higher in CRC tissues compared to matching, adjacent non-cancerous tissues, and healthy controls. Additionally, the levels of OCT4 expression in CRC tissues correlated with tumor stage. OCT4 and Sox-2 were localized in the nuclei and the cytoplasm of CRC cells. In all CRC cases, we found that the OCT4B1 isoform is expressed. Over-expression of OCT4B1 was found in poorly and moderately differentiated CRC tissues. In conclusion, the data imply that OCT4B1 isoform may represent a potential biomarker for the initiation, progression, and differentiation of CRC. Mol. Carcinog. © 2011 Wiley Periodicals, Inc.

Ancillary