Background & aims: Major burdens in the treatment of hepatocellular carcinoma (HCC) are the high percentage of recurrence and resistance to chemotherapy. Hepatic cancer stem cells provide a reservoir of cells that can self-renew, maintain the tumor by generating differentiated non-stem cells which make up the bulk of the tumor and are responsible for recurrence after ablative surgery and chemoradiotherapy. The objective of this study was to identify and characterize a self-renewing subpopulation of human liver tumor cells with a distinctive genetic profile that adds the capacity to proliferate despite chemotherapy and promotes cancer recurrence.
Methods: Stemness properties of tumor cells isolated from a HCC biopsy were established by their capacity to form spheroids and by cell proliferation assays. The cells also showed enhanced chemoresistance to cancer drugs. The up-regulation of stem cell markers is proven by immunocytochemistry stainings and reverse transcription-PCR.
Results: Cells had a high proliferative potential, even when cultured in medium supplemented with doxorubicin and carboplatin, eliminated Rhodamine 123 immediately in culture and also formed spheroids in suspension. Molecular diagnosis techniques showed that cells expressed the stem cell markers Oct 3/4 and CXCR4. Cells were also positive for CD133 and CD90 cancer stem cell specific markers, with monoclonal antibody staining.
Conclusion: The unique characteristics identified in cancer stem cells explain self-renewal and could drive metastasis in patients that have received treatment for cancer. The identification and cloning of such cells can aid in developing of better therapeutic approaches for patients with HCC, as chemosensitive pretherapeutic assays or targeted therapies.