Objective To explore the possible mechanism of Huangqi-Ezhu-Chonglou（黄芪-莪术-重楼

Qi-Zhu-Lou） combination on metastatic colon cancer. Methods Thirty-eight nude mice were divided into blank group（n=8）

model group（n=10）

5-fluorouracil（5-Fu） group（n=10） and Qi-Zhu-Lou group（n=10） by using a random number table. The nude mice in all groups but the blank group were transplanted with human colon cancer HCT116 cells following the orthotopic transplantation method to develop the colon cancer-derived orthotopic transplant model. Twenty-four hours after modeling

the 5-Fu group was given intraperitoneal injection of 25 mg/（kg·d） 5-Fu

once every other day; the Qi-Zhu-Lou group was administered with Qi-Zhu-Lou liquid of 5.85 g/（kg·d） by gavage

once daily; both the blank group and the model group were given 10 ml/（kg·d） normal saline by gavage

once daily. After 21 days of continuous administration

all nude mice were killed to calculate tumor weight and tumor inhibition rate; the expression of tyrosine kinase substrate 5（Tks5）

cortical actin（Cortactin）

phosphorylated cortical actin（p-Cortactin）

cell division cyclin（Cdc42）

adaptor protein 1（Nck1）

filamentous actin（F-actin） and membrane-type matrix metalloproteinase 1（MT1-MMP） protein in tumors and paracancerous tissues of nude mice was detected in each group. Results The tumor inhibition rate of the 5-Fu group and the Qi-Zhu-Lou group was 58.32% and 45.77%

respectively

significantly lower than that of the model group（P<0.01）

and with no significant difference between the two groups（P>0.05）. The protein expressions of invadopodia core protein precursor Tks5 and p-Cortactin

as well as invadopodia maturation-associated protein Cdc42

Nck1

F-actin and MT1-MMP in the tumor and paracancerous tissues of the mice in the model group

Qi-Zhu-Lou group and 5-FU group were significantly higher than those in the blank group（P<0.05 or P<0.01）

while lower than those in the model group（P<0.01）. Conclusion Qi-Zhu-Lou combination may inhibit the growth and metastasis of colon cancer cells by inhibiting the formation and maturation of invadopodia.