Identification and characterisation of NANOG+/ OCT-4high/SOX2+ doxorubicin-resistant stem-like cells from transformed trophoblastic cell lines

Abstract

Treatment of gestational trophoblastic diseases (GTD) involves surgery, radiotherapy and chemotherapy. Although, these therapeutic approaches are highly successful, drug resistance and toxicity remain a concern for high risk patients. This chemo-resistance has also been observed in the presence of cancer stem cells that are thought to be responsible for cases of cancer recurrence. In this study, we report the presence of previously unknown populations of trophoblastic stem-like cells (SLCs) that are resistant to the chemotherapeutic drug doxorubicin. We demonstrate that these populations express the stem cell markers NANOG and Sox2 and higher levels of OCT-4 (NANOG+/OCT-4^high/SOX2+). Although chemoresistant, we show that the invasive capacity of these trophoblastic SLCs is significantly inhibited by doxorubicin treatment. To better characterise these populations, we also identified cellular pathways that are involved in SLCs-chemoresistance to doxorubicin. In summary, we provide evidence of the presence of NANOG+/OCT-4+/SOX2+ trophoblastic SLCs that are capable to contribute to the susceptibility to GTD and that may be involved in chemoresitance associated with drug resistance and recurrence in high risk GTDs’ patients. We propose that targeting these populations could be therapeutically exploited for clinical benefit.