AUTONOMOUS EXPRESSIONS OF CYTOKINE GENES BY HUMAN LUNG-CANCER CELLS AND THEIR PARACRINE REGULATION

Cell-to-cell interaction between tumors and host inflammatory cells is important for the subsequent cancer progression or regression. We exa mined the expressions of mRNAs for various proinflammatory cytokines b y nine human lung cancer cell lines and the influences of cytokines on their gene expressions. The cytokines used were interleukin 1 beta (I L-1 beta), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alph a), granulocyte-macrophage colony stimulating factor (GM-CSF) and mono cyte chemotactic and activating factor. Gene expressions of cytokines were measured by Northern blot analysis. Substantial expressions of cy tokine genes were detected in several lung cancer cell lines such as R ERF-LC-MS, RERF-LC-OK and VMRC-LCD, although the levels of expression of each cytokine varied in different cell lines. Four lung cancer cell lines (RERF-LC-MS, RERF-LC-OK, A549 and YO-88) were used to examine t he effects of exogenous cytokines (IL-1 beta, TNF alpha and GM-CSF) on cytokine gene expressions by the cells. TNF-alpha and IL-1 beta cause d significant changes in the levels of mRNA expressions of certain cyt okines. Moreover, on stimulation with TNF-and, RERF-LC-OK cells produc ed IL-6 extracellularly. These extensive differences in the levels of gene expressions and productions of cytokines could have profound effe cts on the interactions between human lung cancer cells and the corres ponding host cells.