Effective Treatment of Advanced Colorectal Cancer by Rapamycin and 5-FU/Oxaliplatin Monitored by TIMP-1

Wagner, Markus ; Roh, Vincent ; Strehlen, Michael ; Laemmle, Alexander ; Stroka, Deborah ; Egger, Bernhard ; Trochsler, Markus ; Hunt, Kelly ; Candinas, Daniel ; Vorburger, Stephan

In: Journal of Gastrointestinal Surgery, 2009, vol. 13, no. 10, p. 1781-1790

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    Summary
    Aim: The mTOR-inhibitor rapamycin has shown antitumor activity in various tumors. Bedside observations have suggested that rapamycin may be effective as a treatment for colorectal carcinomatosis. Methods: We established an orthotopic syngenic model by transplanting CT26 peritoneal tumors in Balb/C mice and an orthotopic xenograft model by transplanting SW620 peritoneal tumors in nu/nu mice. Expression levels of tissue inhibitor of matrix-metalloproteinases 1 (TIMP-1) in the tumor and serum was determined by enzyme-linked immunosorbent assay. Results: Rapamycin significantly suppressed growth of syngenic and xenografted peritoneal tumors. The effect was similar with intraperitoneal or oral rapamycin administration. Tumor suppression was further enhanced when rapamycin was combined with 5-fluorouracil and/or oxaliplatin. The combination treatment showed no acute toxicity. TIMP-1 serum levels correlated well (CC = 0.75; P < 0.01) with rapamycin treatment. Conclusions: Rapamycin suppressed advanced stage colorectal cancer, even with oral administration. Combining rapamycin with current chemotherapy regimens significantly increased antitumor efficacy without apparent toxicity. The treatment efficacy correlated with serum TIMP-1 levels, suggesting its potential as a surrogate marker in future clinical trials