Bushen Jiedu Prescription Inhibits Metastasis of Colorectal Cancer by Regulating Polarization of M2-TAMs in Vivo / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo explore the inhibitory effect of Bushen Jiedu prescription （BSJDP） on the metastasis of colorectal cancer （CRC） via activation of M2 tumor-associated macrophages （M2-TAMs） in vivo. MethodThe model of xenograft tumor was established with C57BL/6 mice， and then the model mice were randomly assigned into blank control group， Bushen Jiedu recipe-low dose （11.2 g·kg-1） group （BSJDP-L）， and Bushen Jiedu Recipe-high dose （22.4 g·kg-1） group （BSJDP-H）. Tumors were abolished when the volume reached 1.5-2.0 cm3. The mice were sacrificed 28 days post tumor abolishing and then the lung metastasis was observed. Histopathological changes in lung metastasis were examined by hematoxylin-eosin （HE） staining of metastasis tissues， and immunofluorescence （IF） staining was employed to observe the effect of BSJDP on tumor apoptosis and hypoxia. Flow cytometry was performed to analyze the macrophages M1/M2 ratio of tumor tissue. The expression levels of the genes （Arg1， CD206， and CD163） associated with the polarization of M2-TAMs were determined by Real-time fluorescent quantitative polymerase chain reaction （Real-time PCR）. ResultThe metastasis rate was 70%， 40%， and 10% in the blank control group， BSJDP-L group， and BSJDP-H group， respectively. The lower metastasis rates of BSJDP-L and BSJDP-H groups proved that BSJDP significantly inhibited lung metastasis of CRC. Compared with the blank control group， BSJDP-L and BSJDP-H reduced the tumor cell infiltration in tumor tissue （P<0.01）， increased the apoptosis of tumor cells， alleviated the hypoxic environment， and down-regulated the expression of Arg1， CD206， and CD163 in the tumor tissue （P<0.01）. In addition， the ratio of M2 macrophages ranked in a descending order of blank control group （34.867%） > BSJDP-L group （22.033%） > BSJDP-H group （11.633%） （P<0.01）. ConclusionBSJDP inhibits the lung metastasis of CRC by inhibiting the activation of M2-TAMs in the tumor microenvironment.