SUSCEPTIBILITY OF HUMAN COLON-CARCINOMA CELLS TO ANTICANCER DRUGS IS ENHANCED BY L-HISTIDINOL

The effects of L-histidinol on cell cycle transit and anticancer drug susceptibility of four cultured human colon carcinoma cell lines have been examined. The lines studied included two lines, SW480 and SW620, which were derived from the same patient as a grade 111 adenocarcinoma of the colon and a lymphatic metastatic form of colon carcinoma, resp ectively, as well as the human colon adenocarcinoma lines HT-29 and Wi Dr. L-Histidinol accentuates the vulnerability of all of these human c arcinoma lines to several different classes of anticancer drugs, inclu ding 5-fluorouracil, the most effective and most commonly used single agent for metastatic colon carcinoma. The ability of L-histidinol to a ccentuate the sensitivity of these colocarcinoma lines to anticancer d rugs, including those which are cell cycle-dependent, is in apparent c ontradiction to the finding that L-histidinol markedly slows cycle tra nsit in all lines tested.