Molecular profiling of gene copy number abnormalities in key regulatory genes in high-risk B-lineage acute lymphoblastic leukemia: frequency and their association with clinicopathological findings in Indian patients

Abstract Methotrexate (MTX) is one of the most active and widely used agents for the treatment of acute lymphoblastic leukemia (ALL). To elucidate the mechanism for higher accumulation of MTX polyglutamates (MTX-PG) in hyperdiploid ALL and lower accumulation in T-lineage ALL, expression of the reduced folate carrier (RFC) was assessed by reverse transcription-polymerase chain reaction in ALL blasts isolated from newly diagnosed patients. RFC expression exhibited a 60-fold range among 29 children, with significantly higher expression in hyperdiploid B-lineage ALL (median, 11.3) compared with nonhyperdiploid ALL (median, 2.1; P < .0006), but no significant difference between nonhyperdiploid B-lineage and T-lineage ALL. Furthermore, mRNA levels of RFC (mapped by FISH to chromosome 21) were significantly related to chromosome 21 copy number (P = .0013), with the highest expression in hyperdiploid ALL blasts with 4 copies of chromosome 21. To assess the functional significance of gene copy number, MTX-PG accumulation was compared in ALL blasts isolated from 121 patients treated with either low-dose MTX (LDMTX; n = 60) or high-dose MTX (HDMTX; n = 61). After LDMTX, MTX-PG accumulation was highest in hyperdiploid B-lineage ALL with 4 copies of chromosome 21 (P = .011), but MTX-PG accumulation was not significantly related to chromosome 21 copy number after HDMTX (P = .24). These data show higher RFC expression as a mechanism for greater MTX accumulation in hyperdiploid B-lineage ALL and indicate that lineage differences in MTX-PG accumulation are not due to lower RFC expression in T-lineage ALL.

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Gene copy number alterations in Indian children with B-acute Lymphoblastic Leukemia: Correlation with survival outcome

Pediatric Hematology Oncology Journal ◽

10.1016/j.phoj.2021.11.006 ◽

2021 ◽

Author(s):

M. Agarwal ◽

R. Shukla ◽

S.N. Dwivedi ◽

R. Saxena ◽

K. Luthra ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Copy Number ◽

Lymphoblastic Leukemia ◽

Gene Copy Number ◽

Survival Outcome ◽

Gene Copy ◽

Copy Number Alterations ◽

Indian Children

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Reduced Folate Carrier Expression in Acute Lymphoblastic Leukemia: A Mechanism for Ploidy but not Lineage Differences in Methotrexate Accumulation

Blood ◽

10.1182/blood.v93.5.1643.405k06_1643_1650 ◽

1999 ◽

Vol 93 (5) ◽

pp. 1643-1650 ◽

Cited By ~ 3

Author(s):

Vladimir M. Belkov ◽

Eugene Y. Krynetski ◽

John D. Schuetz ◽

Yuri Yanishevski ◽

Eric Masson ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Copy Number ◽

Lymphoblastic Leukemia ◽

Chromosome 21 ◽

Gene Copy ◽

High Dose ◽

Reduced Folate Carrier ◽

Mrna Levels ◽

Significant Difference ◽

B Lineage

Methotrexate (MTX) is one of the most active and widely used agents for the treatment of acute lymphoblastic leukemia (ALL). To elucidate the mechanism for higher accumulation of MTX polyglutamates (MTX-PG) in hyperdiploid ALL and lower accumulation in T-lineage ALL, expression of the reduced folate carrier (RFC) was assessed by reverse transcription-polymerase chain reaction in ALL blasts isolated from newly diagnosed patients. RFC expression exhibited a 60-fold range among 29 children, with significantly higher expression in hyperdiploid B-lineage ALL (median, 11.3) compared with nonhyperdiploid ALL (median, 2.1; P < .0006), but no significant difference between nonhyperdiploid B-lineage and T-lineage ALL. Furthermore, mRNA levels of RFC (mapped by FISH to chromosome 21) were significantly related to chromosome 21 copy number (P = .0013), with the highest expression in hyperdiploid ALL blasts with 4 copies of chromosome 21. To assess the functional significance of gene copy number, MTX-PG accumulation was compared in ALL blasts isolated from 121 patients treated with either low-dose MTX (LDMTX; n = 60) or high-dose MTX (HDMTX; n = 61). After LDMTX, MTX-PG accumulation was highest in hyperdiploid B-lineage ALL with 4 copies of chromosome 21 (P = .011), but MTX-PG accumulation was not significantly related to chromosome 21 copy number after HDMTX (P = .24). These data show higher RFC expression as a mechanism for greater MTX accumulation in hyperdiploid B-lineage ALL and indicate that lineage differences in MTX-PG accumulation are not due to lower RFC expression in T-lineage ALL.

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Gene copy number alteration profile and its clinical correlation in B-cell acute lymphoblastic leukemia

Leukemia & Lymphoma ◽

10.1080/10428194.2016.1193855 ◽

2016 ◽

Vol 58 (2) ◽

pp. 333-342 ◽

Cited By ~ 14

Author(s):

Sanjeev Kumar Gupta ◽

Sameer Bakhshi ◽

Lalit Kumar ◽

Vineet Kumar Kamal ◽

Rajive Kumar

Keyword(s):

Acute Lymphoblastic Leukemia ◽

B Cell ◽

Copy Number ◽

Copy Number Alteration ◽

Lymphoblastic Leukemia ◽

Gene Copy Number ◽

Gene Copy ◽

Clinical Correlation ◽

Cell Acute Lymphoblastic Leukemia

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Evolutionary Trajectories toward Ceftazidime-Avibactam Resistance in Klebsiella pneumoniae Clinical Isolates

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00574-21 ◽

2021 ◽

Author(s):

Alessandra Carattoli ◽

Gabriele Arcari ◽

Giulia Bibbolino ◽

Federica Sacco ◽

Dario Tomolillo ◽

...

Keyword(s):

High Risk ◽

Klebsiella Pneumoniae ◽

Copy Number ◽

Residual Activity ◽

Gene Copy Number ◽

Resistance Mechanisms ◽

University Hospital ◽

Gene Copy ◽

Carbapenemase Gene ◽

Evolutionary Trajectories

From January 2019 to April 2020, 32 KPC-producing, ceftazidime-avibactam (CZA) resistant Klebsiella pneumoniae strains were isolated in a university hospital in Rome, Italy. These strains belonged to the ST512, ST101 and ST307 high-risk clones. Nine different CZA-resistant KPC-3 protein variants were identified, five of them never previously reported (KPC-66 to KPC-70). Among them, KPC-31, KPC-39, KPC-49, KPC-66, KP-68, KPC-69 and KPC-70 showed amino acid substitutions, insertions and deletions in the Ω loop of the protein. KPC-29 has the duplication, while the novel KPC-67 has the triplication of the KDD triplet in the 270-loop of the protein. Genomics performed on contemporary resistant and susceptible clones underlined that those novel mutations emerged in bla KPC-3 genes located on conserved plasmids: in ST512, all bla KPC-3 mutant genes were located in pKpQIL plasmids, while the three novel bla KPC-3 mutants identified in ST101 were on FIIk-FIA(HI1)-R plasmids. Selection also promoted multiplication of the carbapenemase gene copy number by transposition, recombination, and fusion of resident plasmids. When expressed in Escherichia coli recipient cells cloned in the high-copy number pTOPO vector, the Ω loop mutated variants showed CZA-resistant phenotype associated with susceptibility to carbapenems, while KPC variants with insertions in the 270-loop showed residual activity on carbapenems. The investigation of CZA-resistance mechanisms offered the unique opportunity to study vertical, horizontal, and oblique evolutionary trajectories of K. pneumoniae high-risk clones.

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Interleukin-4 induces programmed cell death (apoptosis) in cases of high-risk acute lymphoblastic leukemia

Blood ◽

10.1182/blood.v83.7.1731.1731 ◽

1994 ◽

Vol 83 (7) ◽

pp. 1731-1737 ◽

Cited By ~ 54

Author(s):

A Manabe ◽

E Coustan-Smith ◽

M Kumagai ◽

FG Behm ◽

SC Raimondi ◽

...

Keyword(s):

Bone Marrow ◽

Cell Death ◽

Acute Lymphoblastic Leukemia ◽

High Risk ◽

Programmed Cell Death ◽

B Cell ◽

Lymphoblastic Leukemia ◽

Fatal Outcome ◽

Interleukin 4 ◽

B Lineage

Abstract We investigated the effects of interleukin-4 (IL-4) on the survival of leukemic and normal B-cell progenitors cultured on bone marrow stroma. IL-4 (at 100 U/mL) was cytotoxic in 16 of 21 cases of B-lineage acute lymphoblastic leukemia, causing reductions in CD19+ cell numbers that ranged from 50% to greater than 99% (median 83.5%) of those in parallel cultures not exposed to the cytokine. All nine cases with the t(9;22)(q34;q11) or the t(4;11)(q21;q23), chromosomal features that are often associated with multidrug resistance and a fatal outcome, were susceptible to IL-4 toxicity. IL-4 cytotoxicity resulted from induction of programmed cell death (apoptosis); there was no evidence of cell killing mediated by T, natural killer, or stromal cells. IL-4 cytotoxicity extended to a proportion of normal B-cell progenitors. After 7 days of culture with IL-4 at 100 U/mL, fewer CD19+, CD34+ normal lymphoblasts (the most immature subset) survived: in five experiments the mean (+/- SEM) reduction in cell recoveries caused by IL-4 was 60.0% +/- 6.0%. By contrast, reductions in recovery of more differentiated bone marrow B cells (CD19+, CD34-, surface Ig+) were low (6.6% +/- 2.2%; P < .001 by t-test). Our findings indicate that IL-4 is cytotoxic for human B-cell precursors and support clinical testing of IL-4 in cases of high-risk lymphoblastic leukemia resistant to conventional therapy.

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