Effect of interferon-omega gene transfer on feline mammary carcinoma and melanoma cells

VILLAVERDE MS,; TARGOVNIK AM,; BAFFICO RD, ; MIRANDA MV, ; GLIKIN GC, ; FINOCCHIARO LME;

Congreso; ASGCT; 2013

Interferons are well known for their anti-proliferative effects and immunomodulatory activity. To investigate the effect of feline interferon-w FeIFNw gene lipofection on feline tumor cells, we cloned the corresponding gene in a high expression plasmid vector. Two feline tumor cells were tested: Al (spontaneous mammary carcinoma) and Rn (melanoma). Immunohistochemical staining showed that Al was negative for estrogen and progesterone receptors, and highly positive (3+) for HER2/neu. Only 3-5% of Al nuclei were positive for Ki67 staining. In addition, Al was positive for cytokeratine 18 and vimentin. As expected, Rn was positive for Melan A, vimentin and S100 membrane surface antigen and negative cytokeratine and EMA. HMB-45 was also negative in Rn. Both cell lines were able to growth as monolayers and spheroids (a more representative model of the original tumors) and were sensitive to the addition of exogenous recombinant FeIFN! protein in a concentration-dependent way (Fig.1A). However, over 100 IU/ml Al spheroids were less sensitive to added protein than the corresponding monolayers. On the other hand, when lipofected with FeIFNw gene, tumor cells released to the supernatant signiÞ cant amounts of rFeIFNw protein (1x104-1x105 IU/ml) as determined by biological activity assay and confirmed by western blot analysis. After 5 (monolayers) or 9 (spheroids) days from lipofection, the expressed FeIFNw gene was able to kill more than 60% of cell population (Fig.1B). Both cell lines showed similar response to FeIFNw gene lipofection in both cell culture conÞ gurations (p