Efficacy and cardiotoxicity observation of different doses of capecitabine in patient-derived tumor xenograft of mice with colorectal cancer / 肿瘤研究与临床

ABSTRACT

Objective:To explore the correlation of the dose of capecitabine with the efficacy and cardiotoxicity in patient-derived tumor xenograft (PDX) model of mice with colorectal cancer.Methods:The fresh cancer tissues of 1 colorectal cancer patient were transplanted into the bilateral axillary subcutaneous of immunodeficient NOG mice to establish PDX model and passage stably. And then the morphology of tumor cells in primary generation and the second-generation tumor tissues was observed by using HE staining. The expression of tumor markers was detected by using immunohistochemistry method, and the model was evaluated. Mice were intragastrically infused with 200, 300 and 400 mg/kg capecitabine once a day, which were treated as low, middle and high dose groups respectively, 5 rats in each group; in the control group, 0.9% NaCl solution was perfused into the stomach; 14 d in total, use stop for 7 d, consecutively administered in this way. The body weight was measured every day and the tumor volume was measured every 3 days. After 100 days of observation, the mice were killed, and the tumor tissue was taken to measure the tumor weight and then the tumor volume, tumor volume inhibition rate and tumor inhibition rate were calculated. The morphology of tumor tissues was observed by using HE staining. The protein levels of anti-tumor effect indexes like rasP21, cyclooxygenase 2 (COX2), prostaglandin E2 (PGE2), cardiac troponin Ⅰ (cTn-Ⅰ) and brain natriuretic peptide (BNP) in serum of mice were detected by using enzyme linked immunosorbent assay (ELISA).Results:PDX model of mice with colorectal cancer was successfully constructed, and the histological characteristics of the primary tumor in the model were well preserved. During administration, 1 mouse died in the capecitabine high dose group; a slow down in tumor volume growth could be found with the increased dose of capecitabine. There was no statistically significant difference in body weight among 4 groups until all mice were killed ( P > 0.05). The tumor volume and tumor weight in the low, middle and high dose groups were lower than those in the control group (all P < 0.05), and the tumor volume and tumor weight showed an obvious decrease with the increase in dose. The tumor volume inhibition rates of low, middle and high dose groups were 42.61%, 67.61% and 77.27%, respectively, and the tumor inhibition rates were 35.53%, 67.77% and 75.09%, respectively. The serum anti-tumor effect indexes rasP21, COX2 and PGE2 in the middle and high dose groups were decreased compared with those in the control group (all P < 0.05), while cTn-Ⅰ and BNP levels were increased compared with those in the control group (all P < 0.05). Conclusions:The established PDX model of mice with colorectal cancer can better retain the histological characteristics of the original tumor. After treatment of middle and high dose of capecitabine, the tumor inhibition effect is obvious, but the risk of myocardial damage should be noticed.