Characterization of LEF1 High Expression and Novel Mutations in Adult Acute Lymphoblastic Leukemia

Abstract

Aberrant activation of the Wnt pathway plays a pathogenetic role in tumors and has been associated with adverse outcome in acute lymphoblastic leukemia (ALL). Lymphoid enhancer binding factor 1 (LEF1), a key mediator of Wnt signaling, has been linked to leukemic transformation, and LEF1 mutations have been identified in T-ALL. Here we found LEF1 is highly expressed in 25.0% adult ALL patients and LEF1 high expression was associated with high-risk leukemia factors (high WBC, Philadelphia chromosome positive, complex karyotype), shorter event-free survival (EFS), and high relapse rates in patients with B-ALL. LEF1 high expression is also associated with high mutation rate of Notch1 and JAK1 in T-ALL. We identified 2 novel LEF1 mutations (K86E and P106L) in 4 of 131 patients with ALL, and those patients with high-risk ALL (high WBC, complex karyotype). These results suggest a role for LEF1 mutations in leukemogenesis. We further explored the effect of the mutations on cell proliferation and found both mutations significantly promoted the proliferation of ALL cells. We also observed the effect of LEF1 and its mutations on the transcription of its targets, c-MYC and Cyclin D1. We found LEF1 increased the promoter activity of its targets c-MYC and Cyclin D1, and LEF1 K86E and P106L mutants further significantly enhanced this effect. We also observed that the c-MYC and Cyclin D1 mRNA levels were significantly increased in patients with LEF1 high expression compared with those with low expression. Taken together, our findings indicate high LEF1 expression and mutation are associated with high-risk leukemia and our results also revealed that LEF1 high expression and/or gain-of-function mutations are involved in leukemogenesis of ALL.

Novel dynamin 2 mutations in adult T-cell acute lymphoblastic leukemia

“…The primers for PCR amplification of DNM2 exons were as follows: exon 2 forward, TGC AAG ACA GAG TTG CTC CAC and reverse, TGT GTA AGT GTT CAC TGA GCCG; exon 3 forward, CCA GCC TGG GTC ATT ACT TTC and reverse, ACA CAG GCT CAC CCA TAG CAC; exon 4 forward, GTG GTT CAG GCA GAG TGT CAG and reverse, GAC TTG GAA CCA AGG ATG CTG; exon 5 forward, CTG TGA GAT CAG GGC TGT GAC and reverse, GGA GAA GCA ATG ACT TCC AGG; exon 6 forward, TAC TTG AAT CTT GCC CAT CCC and reverse, CTG AAA CAA GTG CCA GTG AGG; exon 7 forward, ATA GTG GCA CCC TGG TGT TG and reverse, GTG GAC GAG TGA TGA GTG GTG; exon 8 forward, GTA AAC CCT GGC TTG ACT TGG and reverse, CTT GAG ACC TTA TTG CCT GGG; exon 9 forward, GTG TGA GCC ACT GTA TCT GGC and reverse, GGA CTC AGA GGT GTG GGT GAC; exon 10 forward, CAA CCT TCA TTC CTT GTT GGG and reverse, CTG GGA GCC TGA TAC CAA ACC; exon 12 forward, TCT TCT GCT CTT AGC TCC CAG and reverse, TGT CAG CAT GCA CAG AAC AGT; exon 13 forward, TCT GTT GCC TAT GAG GGT GTG and AAT CCC AAC TCA GTC ACC TCC; exon 14 forward, CTA CCT GTG GCT GCT CAC TTG and reverse, TAG AGA GAG CAG ATG GCC TGG; exon 16 forward, GGG CTG GAG GTG TCT CTA TTG and reverse, GCA GTG ACT GAG TTC TGC CC; exon 17 forward, TCA TAT ACA GCA GCG ACC AGC and reverse, GTG CTC AGT GCT CAG TGA AGG; exon 18 forward, CTA GAG CCC ATT CCT CTC GG and reverse, CAT GAT TTC AGA GAC TCC TGGC; exon 19 forward, TAG GGC AGA TGG TTT CCA GAG and reverse, CTC CTT AGC TCG TGA TCC GC; exon 20 forward, CCC GCC CTG TGA GAG ATG and reverse, AGG ACC CTG CAG GAC ACAC; exon 21 forward, CAC CTC AGG TTC TGG CAGC and reverse, ACT GGG AGG AAG TGA GAC AGG; and exon 22 forward, GAG TTG ATG CCT AGG TTT GGC and reverse GAG CCT GGT CCC AGC ATAG. Exons in NOTCH1, FBXW7, PHF6, phosphatase and tensin homolog (PTEN), JAK1 and interleukin (IL)-7R were also amplified as previously reported (11)(12)(13)(14)(15) Cytogenetic and molecular analyses. Conventional cytogenetic analysis was performed at the time of diagnosis, using unstimulated short-term cultures, according to the recommendations of the International System for Human Cytogenetic Nomenclature (16).…”

“…) samples from 42 patients with newly diagnosed T-ALL, consisting of 31 male patients with a median age of 26 years (range, 16-62 years) and 11 female patients with a median age of 29 years (range, 19-60 years), were collected between July 2010 and December 2014 at the First Affiliated Hospital of Nanjing Medical University (Nanjing, Jiangsu, China). The diagnosis of ALL was made according to the morphological, immunophenotypical, cytogenetic and molecular criteria of the 2008 World Health Organization Diagnosis and Classification of ALL (11). All patients provided written informed consent, in accordance with the Declaration of Helsinki, prior to enrollment in the study.…”

WDR5 high expression and its effect on tumorigenesis in leukemia

“…Patients were divided into high and low WDR5 expression groups (Q3–4 vs Q1–2) [55, 56]. For quantitative parameters, overall differences between the cohorts were evaluated using a Mann – Whitney U -test.…”

Co-existence of IL7R high and SH2B3 low expression distinguishes a novel high-risk acute lymphoblastic leukemia with Ikaros dysfunction

“…A cell-surface antigen was defined as positive when fluorescence intensity of at least 20% of cells exceeded fluorescence of negative control as previously described [29, 40]. …”

“…IL7R and SH2B3 expression in patient samples was quantitated as previously described [29, 40]. The expression level of IL7R or SH2B3 was normalized to 18s RNA and expressed as gene expression value of IL7R or SH2B3 /18s RNA.…”