Mechanism Study of Bufalin Reversal of Drug Resistance by Inhibiting Hypoxic Colon Cancer Cell-Induced Polarization of M2 Macrophages.

Chemoresistance is still an important factor affecting the efficacy of treatment in colorectal cancer (CRC) patients. Hypoxia is related to poor prognosis and treatment resistance in cancer. Relevant studies have shown that a hypoxic microenvironment can promote the polarization of M2 macrophages and thus promote tumor development. Previous research has found that bufalin has a wide range of antitumor effects, but whether bufalin can reverse tumor resistance by improving the hypoxic tumor microenvironment is still unclear. In present research, it was found that high expression of SRC-3 in CRC cells under hypoxic conditions promoted the polarization of M2 and caused chemotherapy resistance, while bufalin, a monomeric drug used in Chinese medicine, reduced the level of SRC-3 and HIF-1α, thereby reversing chemoresistance. In addition, overexpression of SRC-3 reduced the hypoxia-mitigating effect of bufalin on CRC cells to promote the polarization of M2. Bufalin also inhibits the polarization of M2 caused by hypoxic CRC cells. Therefore, bufalin has the potential to become a new adjuvant therapy that can be further explored in future studies on its treatment of CRC.