Transformed BHK cells exhibiting normal or subnormal sugar uptake

Abstract

The uptake of deoxyglucose was compared in BHK cells and in DMN4B cells, a conditionally transformed line of BHK cells which exhibits transformed behavior a t 38.5' but not at 32'. At 32', DMN4B cells took up deoxyglucose more slowly than BHK cells, reflecting a higher Km for uptake of this sugar. When both cell lines were grown at 38.5', the Km for DMN4B cells was reduced to a level only slightly greater than for BHK cells, and deoxyglucose uptake became similar in the two cell lines. Growth in glucose-free medium for 22 hours stimulated deoxyglucose uptake in both BHK and DMN4B cells; under these conditions, uptake was equal in the two cells lines, both at 32' and 38.5'. Glycolysis, as measured by lactic acid production, was slower in DMN4B than BHK cells, but in contrast to deoxyglucose uptake, this difference was observed a t 38.5' rather than 32' . The observation that the subnormal deoxyglucose uptake of DMN4B cells in the untransformed state (32') can be normalized by growth a t 38.5', a temperature permissive for transformation, suggests that membrane changes facilitating sugar uptake, which have been found in other transformed cells, are associated with transformation in DMN4B cells as well. However, the failure of uptake to exceed normal in these cells indicates that their transformed behavior is not attributable to excessive sugar uptake per se.

Status and developments of animal cell technology using suspension culture techniques

“…Loss of control over glucose (or other substrates) transport, a widespread phenomenon occuring in transformed cells [33,77,1261, was responsible and the excess glucose taken up was wasted through overproduction and secretion of lactate during the course of the batch culture. It has also been observed that, with this particular cell cultivation procedure, the non-growth-associated utilization of glucose can be reduced and the cell yields can be improved when the addition of glucose is automatically controlled by fed-batch methods.…”