Cellular biochemical and experimental therapeutic studies of L-glutamine and L-asparagine depletion for paediatric sarcoma cells

Allsup, JL

Abstract

The aim of this project was to investigate the cellular biochemical and experimental therapeutic effects of L-glutamine (gin) and L-asparagine (asn) depletion for
paediatric sarcoma cells. The work presented in this thesis describes preclinical studies designed to examine the effect of gin and asn deprivation on cell survival and
cellular metabolism, in rhabdomyosarcoma (A204), osteogenic sarcoma (HOS) and Ewing's sarcoma (TC32) cells. The influence of gin and asn deprivation on the chemosensitivity of drugs employed in treatment protocols currently utilised for these cancer types has also been investigated.
The results presented show that removal of gin and asn both independently and simultaneously can be growth inhibitory, affecting both cell viability and the induction of apoptosis in a time-dependent manner. Surprisingly, little impact on the cell cycle was observed. Overall, gin deprivation was more detrimental to cell growth and survival than asn deprivation with an additive effect being observed following combined gin and asn deprivation.
The effect of reducing gin and asn on gin synthetase (GS) and asn synthetase (AS) mRNA expression levels and intracellular concentrations of gin and asn showed that
effects were cell line dependant. Gin and asn deprivation not only affected the rate of lactate production generated by suspected Warburg metabolism, but also decreased
total glutathione levels which is indicative of alterations in the redox control of these cells.
Reduction of gin and asn gave rise to chemo-potentiative effects in all cells following treatment with doxorubicin (DOX), vincristine (VCR), temozolomide (TMZ), topotecan (TOPO) and cisplatin (CDDP). Most notably, a 70-fold chemopotentiation of TOPO was observed in A204 cells following combined gin and asn deprivation. The only exception was methotrexate (MTX) treatment of HOS cells
where a chemo-protective effect was observed. Results such as this may give insights into new chemotherapeutic regimens that could be developed in order to treat these cancers.

Citation

Allsup, J. Cellular biochemical and experimental therapeutic studies of L-glutamine and L-asparagine depletion for paediatric sarcoma cells. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 3, 2012
• Award Date: Jan 1, 2011