Molecular mechanism of c‐Myc and PRPS1/2 against thiopurine resistance in Burkitt's lymphoma

• DOI: 10.1111/jcmm.15322
• Publication Date: 2020-05-11T09:24:00Z
• Authors: Ting Li; Lili Song; Yingwen Zhang; Yali Han; Zhiyan Zhan; Zhou Xv; Yang Li; Yuejia Tang; Yi Yang; Siqi Wang; Shanshan Li; Liang Zheng; Yanxin Li; Yijin Gao
• Keywords: 0301 basic medicine; Mercaptopurine; Nucleotides; Original Articles; Burkitt Lymphoma; 3. Good health; Proto-Oncogene Proteins c-myc; 03 medical and health sciences; HEK293 Cells; Drug Resistance, Neoplasm; Cell Line, Tumor; Antineoplastic Combined Chemotherapy Protocols; Mutation; Ribose-Phosphate Pyrophosphokinase; Humans; Tetrahydrofolates

AbstractPatients with relapsed/refractory Burkitt's lymphoma (BL) have a dismal prognosis. Current research efforts aim to increase cure rates by identifying high‐risk patients in need of more intensive or novel therapy. The 8q24 chromosomal translocation of the c‐Myc gene, a main molecular marker of BL, is related to the metabolism by regulating phosphoribosyl pyrophosphate synthetase 2 (PRPS2). In our study, BL showed significant resistance to thiopurines. PRPS2 homologous isoenzyme, PRPS1, was demonstrated to play the main role in thiopurine resistance. c‐Myc did not have direct effects on thiopurine resistance in BL for only driving PRPS2. PRPS1 wild type (WT) showed different resistance to 6‐mercaptopurine (6‐mp) in different metabolic cells because it could be inhibited by adenosine diphosphate or guanosine diphosphate negative feedback. PRPS1 A190T mutant could dramatically increase thiopurine resistance in BL. The interim analysis of the Treatment Regimen for Children or Adolescent with mature B cell non‐Hodgkin's lymphoma in China (CCCG‐B‐NHL‐2015 study) confirms the value of high‐dose methotrexate (MTX) and cytarabine (ARA‐C) in high‐risk paediatric patients with BL. However, there remains a subgroup of patients with lactate dehydrogenase higher than four times of the normal value (4N) for whom novel treatments are needed. Notably, we found that the combination of thiopurines and the phosphoribosylglycinamide formyltransferase (GART) inhibitor lometrexol could serve as a therapeutic strategy to overcome thiopurine resistance in BL.