We reported previously that IL-4 induced cell cycle arrest in G1 phase through an increase in p21(WAF1/CIP1) expression in human renal cell carcinoma (RCC) cell lines.
We investigated the association between six functional polymorphisms of IL-4, IL-13, and IL-4R genes and susceptibility to renal cell cancer in a hospital-based study, including 620 renal cell carcinoma (RCC) patients and 623 controls.
IL4 haplotype -589T-33T and -589C-33C were found with a frequency of 0.069 and 0.925, respectively, which represents a two-fold decrease of IL4 haplotype -589T-33T (P < .01) and an increase of IL4 haplotype -589C-33C frequency (P < .05) in metastatic RCC compared with other white reference study populations.
Comparison of various immune manipulation strategies in parallel, bulk PBMCs treated with FP (0.34 microg/ml) plus IL-4 (1000 units/ml) for 1 week and restimulated weekly with FP plus IL-2 (20 IU/ml) induced maximal growth expansion of active T cells expressing the T-cell receptor and specific anti-RCC cytotoxicity, which could be blocked by the addition of anti-HLA class I, anti-CD3, or anti-CD8 antibodies.
These findings help define the biochemical modes of action of IFN-gamma and IL-4 and their potential in the biological therapy of renal cell carcinoma.
Even though IL-13 and IL-4 are homologues and IL-4R and IL-13R have been proposed to share a receptor subunit, IL-4 did not compete for the cytotoxicity mediated by IL13-toxin on RCC.
The function of IL-4R expression on RCC tumor cells was further determined by investigating the effect of IL-4 on tumor cell growth in vitro and comparing it with IL-4 effect on growth of normal fibroblast and endothelial cell lines.