5-aminosalicylic acid and olsalazine inhibit tumor growth in a rodent model of colorectal cancer

The ability of 5-aminosalicylic acid and olsalazine to inhibit colonic aber rant crypts and tumors was investigated in 1,2-dimethylhydrazine-treated ra ts. The effect of these drugs on the rates of tumor apoptosis and prolifera tion was studied as potential mechanisms for their action. 5-Aminosalicylic acid reduced the number of aberrant crypt foci by over one third, while ol salazine had no effect on this parameter. However, both agents effectively reduced tumor number and load, increased the rare of tumor apoptosis, and r educed the rate of tumor cell proliferation. In conclusion, 5-aminosalicyli c acid and olsalazine are both ultimately effective chemopreventive agents in this model; however, only 5-aminosalicylic acid inhibited the formation of aberrant crypt foci. The inhibitory effect of these agents in tumors is related to the inhibition of proliferation and the induction of apoptosis.