Differential Growth Regulation of Human Bladder Tumor Cells (J82) in Culture by Normal Bladder Cells from Different Aged Human Donors

Abstract

This study used an agarose gel culture system to study growth regulatory interactions between normal and neoplastic human bladder cells. The effects of normal human fibroblasts on tumor cell cloning efficiency in agarose was studied using 2 experimental protocols. In 1 system, the fibroblasts proliferated as anchored cells beneath the agarose, and in the other the fibroblasts were nongrowing cells embedded within the agarose as nonanchored cells. In contrast to the largely inhibitory effects of anchored fetal fibroblasts on tumor cell growth, their nonanchored counterparts were exclusively stimulatory. Similar experiments with normal fibroblasts derived from the bladders of increasingly older donors showed a progressive decline in their capacity to inhibit tumor cell growth in agarose. Further experiments modulating the growth rate of neonatal fibroblasts with fetal bovine serum have indicated that the diverse tumor responses elicited by anchored versus nonanchored cells, as well as those observed for the aged bladder fibroblasts, were a function of fibroblast growth rate. We concluded that there was an inverse regulatory relationship between the growth of normal and tumor cells; rapidly growing fibroblasts were inhibitory whereas nongrowing fibroblasts stimulated tumor cell growth in agarose culture.