CHEMOTHERAPY-INDUCED NUCLEAR ALTERATIONS OF MORPHOLOGIC AND GENOMIC CHARACTERISTICS IN A HUMAN COLON-CANCER GRAFTED ONTO NUDE-MICE

PURPOSE: A human Dukes B colonic adenocarcinoma was grafted onto 40 nu de mice. The mice were divided into four groups, one control and three representing experimental conditions. Animals in the three experiment al groups received either adriamycin (ADR), 5-fluorouracil (5-FU), or camptothecin (CPT) over a 25-day period beginning 34 days after grafti ng. Control animals received saline on an identical schedule. Animals were killed 105 days after grafting. METHODS: The effect of therapy wa s assessed by three techniques: 1) tumor size was periodically measure d during the life of the animals, 2) modifications of APC, Ki-ras, and p53 genes were studied by polymerase chain reaction, dot-blot analysi s, restriction analysis, and DNA sequencing, and 3) image cytometry of Feulgen-stained material was used to characterize 15 parameters descr ibing morphometric, densitometric, and textural features of tumor nucl ei. RESULTS: When compared with controls, tumor growth (size) was maxi mumly suppressed by treatment with CPT (P less than or equal to 0.001) . Growth was inhibited significantly by treatment with 5-FU (P less th an or equal to 0.01); no statistical difference in tumor size was obse rved between controls and animals treated with ADR. Modifications of A PC, Ki-ras, and p53 genes were not observed; however, treatment did in hibit amplification of APC and p53 genes. CONCLUSIONS: The 15 morphonu clear parameters were assessed to define populations of cell nuclei al tered by chemotherapy. Although CPT maximally suppressed growth, it di d not alter nuclear morphology when compared with controls. Treatment with either 5-FU or ADR resulted in nuclear morphologic alterations de fined as distinct populations using multivariate analysis. Nonsupervis ed linear discriminant analysis was used to quantify the relative prop ortions of these populations. Four morphonuclear parameters were ident ified, which discriminated nuclei exposed to either ADR or 5-FU from c ontrols.