Clonogenic inactivation of colon cancer-derived cells treated with 5-fluorouracil and indomethacin in hybrid spheroids.

The clonogenic hybrid spheroid assay has been used to determine the toxicity of 5-fluorouracil (5-FU), alone or in combination with indomethacin, in LoVo cells (a human colon adenocarcinoma line). The principal finding was that 5-FU toxicity, determined as loss of colony-forming ability, increased as a function of dose (concentration x duration of exposure), and that indomethacin causes a generalized alleviation of 5-FU toxicity, but only if given concurrently with 5-FU. The implications of these findings in the control of cancer cells by 5-FU are discussed.