INHIBITION OF PROTEIN-KINASE-C DEPENDENT CELL-PROLIFERATION OF HUMAN LUNG-CANCER CELL-LINES BY THE DIHYDROPYRIDINE DEXNIGULDIPINE

The dihydropyridine, dexniguldipine hydrochloride (B859-35), has shown therapeutic activity in experimentally induced neuroendocrine hamster lung tumors and demonstrated antiproliferative effects in a mammary cancer cell line via inhibition of Ca2+ calmodulin. Studies in NIH 3T3 fibroblasts have provided evidence that dexniguldipine may also inhibit protein kinase C (PKC). In this study, we have tested the hypothesis that dexniguldipine may inhibit the proliferation of lung cancer cells in response to autocrine or exogenous activation of PKC. Using a panel of human lung cancer cell lines, we show that dexniguldipine is a potent inhibitor of mitogenic signal transduction pathways dependent on PKC activation in several small-cell and non-small-cell lung cancer cell lines while it failed to inhibit cyclic-AMP-dependent cell proliferation.