Overexpression of HSBP1 is associated with resistance to radiotherapy in oral squamous epithelial carcinoma

Heat shock factor binding protein 1 (HSBP1) has been recognized to regulate early embryonic development. However, HSBP1 expression and function in oral squamous carcinoma (OSCC) have not been studied. We found that HSBP1 expression was elevated in OSCC tissues compared to adjacent normal tissue. Although increased HSBP1 expression was not associated with clinical stage of the disease, it significantly related to outcome after radiotherapy (P < 0.01). Overexpression of HSBP1 enhanced sensitivity of OSCC cells in radiation. Moreover, HSBP1 elevated expression of stem cell markers such as CD44, CD133, ALDH and SOX2, and subsequently enhanced mammosphere formation ability, indicating it drives stem cell-like status in OSCC cells. Furthermore, in mice xenograft tumor model, HSBP1 increased sensitivity of OSCC to radiotherapy. Above all, HSBP1 is a potential marker for prognosis of OSCC after radiotherapy.