Kruppel-like factor 4 promotes high-mobility group box 1-induced chemotherapy resistance in osteosarcoma cells

Osteosarcoma is the most common primary malignant bone tumor, and the frequent acquisition of chemoresistance is often an obstacle to achieving favorable outcomes during chemotherapy. Recently, Kruppel-like factor 4 (KLF4) has been shown to be associated with chemotherapy resistance in a few tumors; however, the involvement of KLF4 in chemotherapy resistance in osteosarcoma cells remains unknown. In this study, quantitative real-time PCR and western blot analysis revealed that KLF4 expression was significantly increased in response to cisplatin, methotrexate and doxorubicin treatment in osteosarcoma cells, and knockdown of KLF4 increased sensitivity to these anticancer drugs by decreasing cellular clonogenic ability and increasing apoptosis. Moreover, our data suggest that KLF4-regulated drug resistance might, at least partially, positively regulate high-mobility group box 1 (HMGB1), which was found to be a significant contributor to chemoresistance in osteosarcoma cells in our previous study. In summary, this study highlights the significance of KLF4/HMGB1 interaction in regulating chemotherapy resistance, and suggests that targeting KLF4/high-mobility group box 1 may be a therapeutic strategy for osteosarcoma chemotherapy.