OBJECTIVEPrimary to search the rule of pre-operative chemotherapy and suitable duration for it by investigating the changes of calpain content and activity after 5'-deoxy-5-fluorouridine (5'-DFUR) per oral administered pre-operatively in different time. Further to investigate the mechanism of chemotherapy.

METHODSSeventy-three patients with gastrointestinal malignant tumors were divided into 4 groups by the time of 5'-DFUR (600 approximately 1200 mg/d) by oral administration before operation, group A, 3 days, 27 cases; group B, 1 week, 22 cases; group C, 2 weeks, 15 cases; group D, 2 months, 9 cases. And group E, control group, had 24 patients with gastrointestinal malignant tumors at the same term. The patients above all had not received the other chemotherapy and radiotherapy. Western blot and immunoelectron microscopy were employed to detect the expressing levels and activities of calpain in tumor tissues of different groups.

RESULTSElectronic microscopic examination showed gold granula mainly on the membranes of mitochondria of tumor cells to groups after chemotherapy. And the tumor cells of group A were mildly damaged. Besides that, serious injury for tumor cells of group B could be seen, and the phenomena were common in group C. But the damages to tumor cells of group D were mainly about mildness. The results of immunoelectron microscopy revealed that the contents of calpain increased following the time of chemotherapy prolonging, and peaked in group C. Still more, there was no significant difference for the results between group C and group D. The changes of calpain activities observed by western blot had the same tendency as the results from immunoelectron microscopy (r = 0.86, P < 0.0001).

CONCLUSIONS5'-DFUR via oral administered pre-operation could have anti-cancer effect through calpain. And the effect might be strongest in 2 weeks also after chemotherapy.