Tongxie Yaofang Regulates Expression of NKG2DL to Enhance Anti-tumor Effect of NK Cells in Colon Cancer under Chronic Stress / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo observe the effect of Tongxie Yaofang on the function of tumor-related natural killer （NK） cells under chronic stress and explore the possible molecular mechanism. MethodFifty SPF-grade BABL/C male mice were randomized into normal， model， and low-， medium-， and high-dose （6.825， 13.65， and 27.3 g·kg-1， respectively） Tongxie Yaofang groups， with 10 mice in each group. Other groups except the blank group were subjected to 7 days of chronic restraint stress， and then forced swimming and tail suspension tests were carried out to evaluate the modeling performance. After the successful modeling， rats in Tongxie Yaofang groups were administrated with low-， medium-， and high-doses of Tongxie Yaofang by gavage， while those in the other groups were administrated with normal saline by gavage. After 14 days， each group of mice was inoculated with subcutaneous colon cancer to establish the model of colon cancer under chronic stress. The pathological changes of the tumor tissue in each group of mice were observed using hematoxylin-eosin （HE） staining. The content of CD49b-positive cells in the peripheral blood and tumor tissue of mice was measured by flow cytometry. Enzyme-linked immunosorbent assay （ELISA） was employed to measure the content of molecules associated with NK cell activation in the peripheral blood. Western blot was employed to determine the protein levels of major histocompatibility complex class Ⅰ polypeptide-related sequences A and B （MICA+MICB） and UL-16-binding protein 1 （ULBP1） in the tumor tissue. ResultCompared with the normal group， the model group showed a decrease in 5-hydroxytryptamine （5-HT） content and an increase in corticosterone （CORT） content in the serum （P<0.05）. Compared with the model group， Tongxie Yaofang increased the 5-HT content and decreased the CORT content （P<0.05， P<0.01）. Compared with the normal group， the modeling increased the tumor volume and weight （P<0.05）， while Tongxie Yaofang inhibited such increases with no statistical significance. The tumor cells in the model group presented neat arrangement， irregular shape， uneven size， obvious atypia， common nuclear division， and small necrotic area， and blood vessels were abundant surrounding the tumor cells. Compared with the model group， Tongxie Yaofang groups showed sparse arrangement of tumor cells， different degrees of patchy necrosis areas in the tumor， and karyorrhexis， dissolution， and nuclear debris in the necrotic part. Compared with the normal group， the model group showed reduced CD49b-positive cells in the peripheral blood and tumor tissue （P<0.01）. Compared with the model group， Tongxie Yaofang increased CD49b-positive cells （medium dose P<0.01， high dose P<0.05， P<0.01）. Compared with the normal group， the modeling lowered the serum levels of granzymes-B （Gzms-B）， perforin （PF）， interferon （IFN）-γ， and tumor necrosis factor （TNF）-α （P<0.05， P<0.01）. Compared with the model group， low-dose Tongxie Yaofang elevated the serum levels of PF， Gzms-B， and TNF-α （P<0.05， P<0.01）， and medium-dose Tongxie Yaofang elevated the serum levels of Gzms-B， PF， IFN-γ， and TNF-α （P<0.05， P<0.01）. In addition， high-dose Tongxie Yaofang elevated the serum levels of PF， IFN-γ， and TNF-α （P<0.01）. Compared with the normal group， the model group presented down-regulated protein level of ULBP1 （P<0.05）. Compared with the model group， low-， medium-， and high-dose Tongxie Yaofang up-regulated the protein level of ULBP1 （P<0.05， P<0.01）， and medium- and high-dose Tongxie Yaofang up-regulated the protein level of MICA+MICB （P<0.05， P<0.01）. ConclusionTongxie Yaofang may promote NK cell activation by up-regulating the expression of MICA+MICB and ULBP1， thereby delaying the progression of colon cancer under chronic stress.