In-vitro anti-proliferative effects of some anti-tumour drugs on feline mammary tumour cell lines.

Six anti-tumour drugs namely; doxorubicin, mitoxantrone, vincristine, cisplatin, recombinant human tumour necrosis factor alpha (rh-TNFalpha) and recombinant feline interferon gamma (rf-IFNgamma) were singly evaluated for their anti-proliferative effects on two feline cell lines (FRM and NAC) derived from mammary adenocarcinoma and grown as monolayers. We obtained concentration response curves that enabled the determination of the concentration inhibiting growth by 50 per cent (IC50) for the chemotherapeutic agents with VCR exhibiting exponential-plateau curves. Differences in anti-proliferative effects of drugs to a given cell line and between the cell lines were also observed. NAC cells were relatively more resistant compared with FRM cells. The relative resistances for NAC cells were 4.19, 12.96, 0.05 and 2.10-fold to doxorubicin, mitoxantrone, vincristine and cisplatin, respectively. FRM cells were more resistant to VCR at lower concentrations compared with NAC cells. The cells appeared, at least in vitro, least sensitive to rh-TNFalpha and rf-IFNgamma. rh-TNFalpha and rf-IFNgamma were 23 and 29 per cent inhibitory to FRM cells and only 13 and 15 per cent inhibitory to NAC cells, respectively. Copyright 1999 W.B. Saunders Company Ltd.