Glutamine metabolism fuels de novo purine synthesis in Multiple Myeloma for DNA replication and cell proliferation Open Access
Swen, Colin (Spring 2021)
Abstract
Multiple Myeloma is the second most common hematological malignancy and accounts for approximately 10% of all blood cancers. It is currently considered incurable which stresses the need for better therapies. Myeloma cells have shown an interesting dependence on glutamine uptake and upregulation of glutamine transporters. Genetic perturbation of the glutamine transporter ASCT2 has been shown to reduce tumor growth in myeloma and small molecule inhibitors targeting ASCT2, such as V-9302, have had anti-tumor effects in several cancers in preclinical studies. The current literature in myeloma suggests that glutamine is needed by myeloma cells to replenish the TCA cycle intermediate alpha ketoglutarate and sustain ATP synthesis. This hypothesis is based on the high activity of the glutaminase enzyme GLS1 which hydrolyzes glutamine to glutamate. However, there are several metabolic pathways that involve glutamine and play key roles in myeloma including glutathione synthesis, protein glycosylation, and nucleotide synthesis. Our bioinformatics analysis suggested that de novo purine synthesis was an important pathway for glutamine in myeloma and could be playing a key role in glutamine addiction seen in myeloma.
My hypothesis was that myeloma cells increase glutamine uptake and glutamine dependence after transformation because of the need to synthesize purines de novo to fuel DNA replication for increased proliferation. Rewired metabolism is an established feature of cancer in order to meet the metabolic needs of a cancer cell. Plasma cells are terminally differentiated non-dividing cells which means that new pathways must be turned on to sustain cell growth and division when they transform into myeloma cells. Our findings show a cytostatic effect of glutamine deprivation on myeloma cells. Similarly, when we knocked out genes in the de novo purine synthesis pathway using CRISPR/Cas9 we saw a reduction in proliferation, signifying that this is a key pathway for myeloma growth. Overall, our findings suggest that targeting de novo purine synthesis and glutamine metabolism could be an effective myeloma therapy.
Table of Contents
Table of Contents
Introduction and Background Information
What is Multiple Myeloma 1
Staging and Progression of Multiple Myeloma 1
Current Treatments for Multiple Myeloma 2
Glutamine metabolism overview 4
Purine Metabolism 11
Experimental Model 13
Scope of thesis 14
Materials and Methods
CRISPR/CAS9 KO generation 15
Cell Titer Glo 15
Western Blotting 16
Cell Proliferation experiment 16
Results
ASCT2 Expression Increased in Myeloma and Inhibition of ASCT2 restricts growth 17
Expression of de novo Purine Synthesis Pathway Upregulated in Myeloma 18
PPAT Expression Correlated with Worse Patient OS and PFS 20
Metabolite Profiling Data 21
PPAT KO causes reduced proliferation in myeloma cell line KMS11 22
Discussion 23
References 26
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Glutamine metabolism fuels de novo purine synthesis in Multiple Myeloma for DNA replication and cell proliferation () | 2021-04-16 13:33:53 -0400 |
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