Colony inhibitory effect of recombinant human tumor necrosis factor (rH-TNF) and/or recombinant human interferon (rH-IFN)-alpha, -beta and -gamma on human lung cancer cell lines.

This study was conducted to assess, by continuous exposure, the inhibitory effects of rH-TNF and rH-IFN-alpha, -beta and -gamma, either alone or in combination, on the colony formations of human lung cancer cell lines. The cell lines tested were PC-7 and PC-9 (adenocarcinoma), PC-10 (squamous cell carcinoma) and PC-13 (large cell carcinoma). Additional experiments were performed with L929 (transformed murine fibroblast), because of its known high sensitivity to TNF. rH-TNF inhibited the colony formations of PC-10 and L929 even at a low concentration (10 U/ml). However, PC-7, PC-9 and PC-13 were resistant to rH-TNF. rH-IFN-alpha, -beta and -gamma inhibited the colony formation of PC-10 (less than 50% of control) at the highest concentration tested (10(4) U/ml), but only rH-IFN-beta inhibited that of PC-7. PC-9, PC-13 and L929 were insensitive to all three rH-IFNs, even at the highest concentrations tested. Combination effects of rH-TNF and rH-IFN-alpha or -gamma were synergistic only at the highest concentration combinations tested in PC-9. However, the maximum inhibition of colony formation of PC-7, PC-9 or PC-13 in any concentration combination treatment was less than 50%.