Resistance of t(17;19)‐acute lymphoblastic leukemia cell lines to multiagents in induction therapy

Abstract

t(17;19)(q21‐q22;p13), responsible for TCF3‐HLF fusion, is a rare translocation in childhood B‐cell precursor acute lymphoblastic leukemia(BCP‐ALL). t(1;19)(q23;p13), producing TCF3‐PBX1 fusion, is a common translocation in childhood BCP‐ALL. Prognosis of t(17;19)‐ALL is extremely poor, while that of t(1;19)‐ALL has recently improved dramatically in intensified chemotherapy. In this study, TCF3‐HLF mRNA was detectable at a high level during induction therapy in a newly diagnosed t(17;19)‐ALL case, while TCF3‐PBX1 mRNA was undetectable at the end of induction therapy in most newly diagnosed t(1;19)‐ALL cases. Using 4 t(17;19)‐ALL and 16 t(1;19)‐ALL cell lines, drug response profiling was analyzed. t(17;19)‐ALL cell lines were found to be significantly more resistant to vincristine (VCR), daunorubicin (DNR), and prednisolone (Pred) than t(1;19)‐ALL cell lines. Sensitivities to three (Pred, VCR, and l ‐asparaginase [ l ‐Asp]), four (Pred, VCR, l ‐Asp, and DNR) and five (Pred, VCR, l ‐Asp, DNR, and cyclophosphamide) agents, widely used in induction therapy, were significantly poorer for t(17;19)‐ALL cell lines than for t(1;19)‐ALL cell lines. Consistent with poor responses to VCR and DNR, gene and protein expression levels of P‐glycoprotein (P‐gp) were higher in t(17;19)‐ALL cell lines than in t(1;19)‐ALL cell lines. Inhibitors for P‐gp sensitized P‐gp‐positive t(17;19)‐ALL cell lines to VCR and DNR. Knockout of P‐gp by CRISPRCas9 overcame resistance to VCR and DNR in the P‐gp‐positive t(17;19)‐ALL cell line. A combination of cyclosporine A with DNR prolonged survival of NSG mice inoculated with P‐gp‐positive t(17;19)‐ALL cell line. These findings indicate involvement of P‐gp in resistance to VCR and DNR in Pgp positive t(17;19)‐ALL cell lines. In all four t(17;19)‐ALL cell lines, RAS pathway mutation was detected. Furthermore, among 16 t(1;19)‐ALL cell lines, multiagent resistance was usually observed in the cell lines with RAS pathway mutation in comparison to those without it, suggesting at least a partial involvement of RAS pathway mutation in multiagent resistance of t(17;19)‐ALL.

Comprehensive chromosomal aberrations in a case of a patient with TCF3-HLF-positive BCP-ALL

“…Despite the rarity of childhood ALL, t(17;19) is being increasingly recognized as a clinically significant chromosomal rearrangement. According to drug screening results, TCF3-HLF-bearing tumour cells obtained from paediatric patients show resistance to standard therapy, including nucleotide analogues (e.g., cytarabine) and mitotic spindle inhibitors (e.g., vincristine) but are sensitive to glucocorticoids [15]. Studies to date show that the use of tyrosine kinase inhibitors or CD19directed immunotherapy can improve the quality of remission in TCF3-HLF-positive ALL patients [16].…”

Effects of different aberrations in the CRLF2 gene on the biological characteristics and drug sensitivities of Nalm6 cells

“…To assess the overall sensitivity of the four Nalm6 cell lines overexpressing CRLF2 , CRLF2 + IK6 , P2RY8 ‐ CRLF2 and CRLF2 F232C to the multiple drugs used during treatment, the sensitivity of the cells to a three‐ (DNR, VCR and DEX) and a four‐drug (DNR, VCR, DEX and CTX) combination was analysed (Table 2). The total score for drug sensitivity was higher in each of the four cell lines overexpressing CRLF2 , CRLF2 + IK6 , P2RY8 ‐ CRLF2 and CRLF2 F232C than in the control group (Figure 3G and 3H), indicating that the four Nalm6 cell lines with upregulated CRLF2 expression exhibited substantially higher resistance to the drugs that are commonly used during treatment than cell lines expressing normal levels of CRLF2 9 …”

Association of relapse-linked ARID5B single nucleotide polymorphisms with drug resistance in B-cell precursor acute lymphoblastic leukemia cell lines

“…Fifty percent inhibitory concentration (IC50) values of prednisolone (Pred), dexamethasone (Dex), vincristine (VCR), daunorubicin (DNR), L-asparaginase (L-Asp), cytarabine (AraC), methotrexate (MTX), mercaptopurine (6MP), and mafosfamide [Maf; active metabolite of cyclophosphamide (CY)] were determined using the alamarBlue cell viability assay (Bio-Rad Laboratories, Hercules, CA) as previously reported [ 17 ]. Cells (1–4 × 10 5 ) were placed onto 96-well flat bottom plates in the presence or absence of seven separate concentrations of each drug in triplicate.…”