Detection of tumor stem cell markers in pancreatic carcinoma cell lines
Monika Olempska, Patricia Alice Eisenach, Ole Ammerpohl, Hendrik Ungefroren, Fred Fandrich and Holger Kalthoff
Kiel, Germany
Author Affiliations: Department of General and Thoracic Surgery, University Hospital Schleswig-Holstein, Campus Kiel, Arnold Heller Str. 7, 24 105 Kiel, Germany (Olempska M, Eisenach PA, Ammerpohl O, Ungefroren H, Fandrich F and Kalthoff H) Corresponding Author: Holger Kalthoff, PhD, Department of General and Thoracic Surgery, Division of Molecular Oncology, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller Str. 7, 24105 Kiel, Germany (Tel: +49-431-5971937, Fax: +49-431-5971939, Email: hkalthoff@email.uni-kiel.de)
BACKGROUND: Cancer of the pancreas is the fourth leading cause of cancer death in industrialized countries. In malignancy, actively proliferating cells may be effectively targeted and killed by anti-cancer therapies, but stem cells may survive and support re-growth of the tumor. Thus, new strategies for the treatment of cancer clearly will also have to target cancer stem cells. The goal of the present study was to determine whether pancreatic carcinoma cell growth may be driven by a subpopulation of cancer stem cells. Because previous data implicated ABCG2 and CD133 as stem cell markers in hematopoietic and neural stem/progenitor cells, we analyzed the expression of these two proteins in pancreatic carcinoma cell lines.
METHODS: Five established pancreatic adenocarcinoma cell lines were analyzed. Total RNA was isolated and real-time RT-PCR was performed to determine the expression of ABCG2 and CD133. Surface expression of ABCG2 and CD133 was analyzed by flow cytometric analysis.
RESULTS: All pancreatic carcinoma cell lines tested expressed significantly higher levels of ABCG2 than non-malignant fibroblasts or two other malignant non-pancreatic cell lines, i.e., SaOS2 osteosarcoma and SKOV3 ovarian cancer. Elevated CD133 expression was found in two out of five pancreatic carcinoma cell lines tested. Using flow cytometric analysis we confirmed surface expression of ABCG2 in all five lines. Yet, CD133 surface expression was detectable in the two cell lines, A818-6 and PancTu1, which exhibited higher mRNA levels.
CONCLUSIONS: Two stem cell markers, ABCG2 and CD133 are expressed in pancreatic carcinoma cell lines. ABCG2 and/or CD133 positive cells may represent subpopulation of putative cancer stem cells also in this malignancy. Because cancer stem cells are thought to be responsible for tumor initiation and its recurrence after an initial response to chemotherapy, they may be a very promising target for new drug developments.
2007, Vol. 6 
