Studies of glucose metabolism in tumour cells and hybrids derived from them

Thesis

Earlier studies had shown that an abnormality in the carbohydrate moiety of a cell membrane glycoprotein was closely linked to malignancy and that this glycoprotein might function in the transport of glucose into the cell. In this study the possibility that functional alterations in hexose transport might be linked to malignancy was investigated.

The kinetic parameters of uptake of the hexose 2-deoxy-D-glucose were measured for a variety of cell types and for hybrids between malignant and non-malignant cells. Hybrids in which malignancy was suppressed were compared to segregant tumours derived from them. Non-tumorigenic derivatives of tumour cells were also investigated. In every case, malignancy, i.e. the ability to grow progressively in vivo, was found to be linked to a decrease in the Michaelis constant of uptake. This association was found for both mouse and human cells and hybrids.

Independent measurement of the transport and phosphorylation steps involved in uptake revealed that this difference resided in the transport step which was rate-limiting for overall uptake.

Malignancy was also associated with a difference in response to glucose deprivation. The maximum velocity of hexose uptake of malignant cells was increased by glucose deprivation whereas that of non-malignant cells remained largely unchanged.

The maximum velocity of fibroblastic cells was increased by viral transformation.

The Michaelis constant of uptake was increased by tunicamycin demonstrating the importance of glycoprotein glycosylation for hexose transport.

Autoradiographic analysis of the distribution of hexose uptake capacity within cell populations revealed marked heterogeneity. There was a fast-transporting sub-population and enrichment for this was achieved in cell fractionation experiments with the monoclonal antibody M/27 which defines a transportassociated antigen.

Measurement of the uptake of D-glucose itself by rapid filtration centrifugation gave similar results to those obtained with 2-deoxy-D-glucose.

Authors: White, M; White, Martyn K

• Publication date: 1982
• DOI: 10.5287/ora-no00ozoak
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Subjects: Metabolism; Glucose; Tumors