Lanreotide-induced modulation of 5-fluorouracil or mitomycin C cytotoxicity in human colon cancer cell lines: a preclinical study

The effect on growth of the long-acting somatostatin analogue lanreotide (L AN), alone or in combination with 5-fluorouracil (5-FU) and mitomycin C (MI T), was investigated in three human colon cancer lines, Cell survival inhib ition induced by LAN alone, as evaluated by sulforhodamine B assay, ranged from 20% to 40% as a function of cell line and concentration. The IC the co ncentration inhibiting cell survival by 50%, was never reached. The IC50, t he proliferative effect produced by a 48h exposure to 5-FU or MIT was syner gistically enhanced in all cell lines by a subsequent 48h exposure to LAN. The synergistic interaction was not related to specific cell cycle perturba tions or to the somatostatin receptor 2 (sst2) mRNA abundance. In conclusio n, our study seems to indicate that LAN is a potentially useful modulating agent for enhancing 5-FU and MIT activity in colorectal cancer patients.