Annotation Detail

Information
Associated Genes
PRPS1
Associated Variants
PRPS1 L191F
PRPS1 L191F
Associated Disease
childhood B-cell acute lymphoblastic leukemia
Source Database
CIViC Evidence
Description
Lentiviral-mediated overexpression of PRPS1 L191F in Reh cells resulted in significant resistance against mercaptopurine (6-MP) and thioguanine (6-TG) as indicated by IC50 increases and reduced apoptosis compared to multiple controls (empty vector and overexpression of wildtype or known reduced-function PRPS1 mutants). 6-MP cytotoxicity results were confirmed using Jurkat cells. After 6-MP exposure, mass spectrometry revealed L191F cells possessed reduced concentrations of intracellular 6-MP metabolites (TIMP, TGMP, etc.) versus controls. L191F cells produce increased intracellular concentrations of hypoxanthine and IMP. Also, after 6-MP exposure, L191F cells display reduced levels of DNA damage response and apoptosis protein markers. The enhanced production of hypoxanthine likely leads to reduced conversion of thiopurines to their active form due to competitive inhibition.
Variant Origin
somatic
Variant Origin
Somatic
Evidence URL
https://civic.genome.wustl.edu/links/evidence_items/7899
Gene URL
https://civic.genome.wustl.edu/links/genes/4566
Variant URL
https://civic.genome.wustl.edu/links/variants/2919
Rating
4
Evidence Type
Predictive
Disease
Childhood B-cell Acute Lymphoblastic Leukemia
Evidence Direction
Supports
Drug
Thioguanine,Mercaptopurine
Evidence Level
D
Clinical Significance
Resistance
Pubmed
25962120
Drugs
Drug NameSensitivitySupported
MercaptopurineResitance or Non-Reponsetrue
ThioguanineResitance or Non-Reponsetrue