Effect of Qingzao Jiufei Tang on JAK2/STAT3 Signaling Pathway and Expression of Downstream Apoptosis-related Proteins in Lung Cancer / 中国实验方剂学杂志

ABSTRACT

Objective:To observe the effect of Qingzao Jiufei Tang on apoptosis of lung cancer, Janus protein tyrosine kinase 2/signal transducers and transcriptional activator protein 3 (JAK2/STAT3) signaling pathway, as well as the expressions of downstream apoptosis-related proteins Bcl-2-associated X (Bax) and Cyclin D1. Method:Totally 50 male C57BL/6J mice were randomly divided into five groups chemotherapy group (CTX), model group, high-dose Qingzao Jiufei Tang group, middle-dose Qingzao Jiufei Tang group and low-dose Qingzao Jiufei Tang group, with 10 mice in each group. The model of lung cancer was established by injecting Lewis lung cancer cells into the right axillary of mice. High-dose, middle-dose and low-dose Qingzao Jiufei Tang groups were orally given drugs (11, 5.5, 2.75 g·kg-1·d-1) two weeks before the modeling. Chemotherapy group was administered intraperitoneally at a dose of 50 mg·kg-1·(2 d)-1, while model group was administered intragastrically with the equal volume of normal saline. After inoculation, the mice in each group were continued to be administered. Two weeks later, the mice in each group were killed, and the tumors were collected. Then the JAK2 protein phosphorylation level was detected by immunohistochemistry (IHC). STAT3, Bax and Cyclin D1 protein expression levels were detected by Western blot, and apoptosis of lung cancer cells was observed by transmission electron microscopy. Result:Compared with model group, the phosphorylation levels of JAK2 and STAT3 protein in lung cancer cells were significantly decreased, the expression of Bax protein was significantly increased, and the expression of Cyclin D1 protein was significantly decreased in high-dose Qingzao Jiufei Tang group, middle-dose Qingzao Jiufei Tang group and chemotherapy group, with statistically significant differences (P<0.05, P<0.01). The results of transmission electron microscopy showed significant apoptotic phenomena in high-dose Qingzao Jiufei Tang group, middle-dose Qingzao Jiufei Tang group, low-dose Qingzao Jiufei Tang group and chemotherapy group compared with the model group. Conclusion:Qingzao Jiufei Tang had an obvious effect in promoting the apoptosis of lung cancer cells. Its mechanism may be related to the inhibition of the phosphorylation of JAK2 and STAT3 protein, the promotion of its downstream Bax protein expression and the inhibition of its downstream Cyclin D1 protein expression.