Characterization of newly established Pralatrexate-resistant cell lines and the mechanisms of resistance

BMC Cancer

Kana Oiwa¹  Rie Nishi¹  Naoko Hosono¹  Takahiro Yamauchi¹  Luigi Scotto²  Owen A. O’Connor³ 

[1] Department of Hematology and Oncology, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, 910-1193, Fukui, Japan;The Center of Lymphoid Malignancy, Columbia University Medical Center, College of Physicians and Surgeons, 630 West 168th St, 10032, New York, NY, USA;The Center of Lymphoid Malignancy, Columbia University Medical Center, College of Physicians and Surgeons, 630 West 168th St, 10032, New York, NY, USA;Department of Medicine, Division of Hematology and Oncology, University of Virginia, 1215 Lee Street, 22903, Charlottesville, VA, USA;

关键词: Pralatrexate;    Resistance;    DNA-methyltransferase 3β;    Decitabine;   

DOI  :  10.1186/s12885-021-08607-9

来源: Springer

【 摘 要 】

BackgroundPralatrexate (PDX) is a novel antifolate approved for the treatment of patients with relapsed/refractory peripheral T-cell lymphoma, but some patients exhibit intrinsic resistance or develop acquired resistance. Here, we evaluated the mechanisms underlying acquired resistance to PDX and explored potential therapeutic strategies to overcome PDX resistance.MethodsTo investigate PDX resistance, we established two PDX-resistant T-lymphoblastic leukemia cell lines (CEM and MOLT4) through continuous exposure to increasing doses of PDX. The resistance mechanisms were evaluated by measuring PDX uptake, apoptosis induction and folate metabolism-related protein expression. We also applied gene expression analysis and methylation profiling to identify the mechanisms of resistance. We then explored rational drug combinations using a spheroid (3D)-culture assay.ResultsCompared with their parental cells, PDX-resistant cells exhibited a 30-fold increase in half-maximal inhibitory concentration values. Induction of apoptosis by PDX was significantly decreased in both PDX-resistant cell lines. Intracellular uptake of [14C]-PDX decreased in PDX-resistant CEM cells but not in PDX-resistant MOLT4 cells. There was no significant change in expression of dihydrofolate reductase (DHFR) or folylpolyglutamate synthetase (FPGS). Gene expression array analysis revealed that DNA-methyltransferase 3β (DNMT3B) expression was significantly elevated in both cell lines. Gene set enrichment analysis revealed that adipogenesis and mTORC1 signaling pathways were commonly upregulated in both resistant cell lines. Moreover, CpG island hypermethylation was observed in both PDX resistant cells lines. In the 3D-culture assay, decitabine (DAC) plus PDX showed synergistic effects in PDX-resistant cell lines compared with parental lines.ConclusionsThe resistance mechanisms of PDX were associated with reduced cellular uptake of PDX and/or overexpression of DNMT3B. Epigenetic alterations were also considered to play a role in the resistance mechanism. The combination of DAC and PDX exhibited synergistic activity, and thus, this approach might improve the clinical efficacy of PDX.

【 授权许可】

CC BY