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Leukemia-initiating HSCs in chronic lymphocytic leukemia reveal clonal leukemogenesis and differential drug sensitivity. Cell Rep 2022; 40:111115. [PMID: 35858552 DOI: 10.1016/j.celrep.2022.111115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 02/15/2022] [Accepted: 06/29/2022] [Indexed: 11/25/2022] Open
Abstract
The existence of "leukemia-initiating cells" (LICs) in chronic lymphocytic leukemia (CLL) remains controversial due to the difficulty in isolating and identifying the tumor-initiating cells. Here, we demonstrate a microchannel electroporation (MEP) microarray that injects RNA-detecting probes into single live cells, allowing the imaging and characterization of heterogeneous LICs by intracellular RNA expression. Using limited-cell FACS sequencing (LC-FACSeq), we can detect and monitor rare live LICs during leukemogenesis and characterize their differential drug sensitivity. Disease-associated mutation accumulation in developing B lymphoid but not myeloid lineage in CLL patient hematopoietic stem cells (CLL-HSCs), and development of independent clonal CLL-like cells in murine patient-derived xenograft models, suggests the existence of CLL LICs. Furthermore, we identify differential protein ubiquitination and unfolding response signatures in GATA2high CLL-HSCs that exhibit increased sensitivity to lenalidomide and resistance to fludarabine compared to GATA2lowCLL-HSCs. These results highlight the existence of therapeutically targetable disease precursors in CLL.
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Abstract 1620: Clonal hematopoiesis of indeterminate potential in the companion dog. Cancer Res 2022. [DOI: 10.1158/1538-7445.am2022-1620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Clonal hematopoiesis of indeterminate potential (CHIP) is a clinical entity of aging humans that is characterized by cancer-associated mutations in white blood cells, without evidence of overt neoplasia. CHIP has been associated with an increased risk of hematologic cancers, cardiovascular disease, and all-cause mortality. We hypothesized that somatic mutations in specific genes associated with human CHIP would be detectable in the blood of aged dogs not known to have hematologic disorders.
Methods: DNA from paired germline and whole blood samples from 93 geriatric canine patients affected by solid cancer were subjected to targeted next generation sequencing. Impact of the variants was predicted using Polymorphism Phenotyping version 2 software (PolyPhen-2, Harvard). Clinical and demographic data were extracted from medical records.
Results: Somatic variants were detected in peripheral blood of four (4.3%) female dogs aged 12-15 years. Affected genes were ASXL1, KIT, SF3B1, TET2, RUNX1, and PPM1D. The variant in PPM1D was a nonsense mutation, while the other five variants were single nucleotide non-synonymous variants in protein coding regions of the genes. Following analysis by PolyPhen-2, the single nucleotide variants in KIT and SF3B1 were predicted to be benign, while the variants in ASXL1, TET2, and RUNX1 were predicted to be damaging. Conclusion: These results support the presence of variants in CHIP-associated genes in geriatric canids at a frequency similar to that observed in people, and the dog represents the first species in which the genetic lesion of CHIP has been documented. Further investigations are needed to confirm the association of this genetic lesion with clinical outcomes.
Citation Format: Kimberley N. Sebastian, Hatice Gülçin Özer, Cory Howard, Laura Chadsey, Arletta Lozanski, Tzyy-Jye Doong, Gerard Lozanski, Wenjuan Ma, William C. Kisseberth, John C. Byrd, Bonnie K. Harrington. Clonal hematopoiesis of indeterminate potential in the companion dog [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1620.
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Four-year follow-up from a phase 2 study of obinutuzumab, ibrutinib, and venetoclax in CLL. J Clin Oncol 2022. [DOI: 10.1200/jco.2022.40.16_suppl.7540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
7540 Background: Targeted agent combinations for chronic lymphocytic leukemia (CLL) have resulted in safe regimens with improved progression-free survival (PFS) compared to chemoimmunotherapy. The optimal regimen and long-term outcomes remain unknown. We conducted a phase 2 study of obinutuzumab (OBIN), ibrutinib (IBR), and venetoclax (VEN) in relapsed/refractory (RR) and treatment-naïve (TN) CLL patients (pts) and report extended follow up on two previously reported cohorts (RR, TN 1) and a new cohort of identically treated TN pts (TN 2). Methods: Pts with TN or RR (≥1 prior treatment) CLL requiring treatment were eligible. Treatment was given for 14 28-day cycles (C). OBIN was started C1, IBR C2, and VEN C3 with standard dose escalation. Response was assessed 2 months (mos) after C14 (EOT) by iwCLL 2008 criteria. Minimal residual disease (MRD) was measured by 10-color flow cytometry with a cutoff of < 1x10-4. The primary endpoint was complete remission (CR) with undetectable MRD (uMRD) in blood and bone marrow at EOT. A sample size of 25 pts per cohort achieves 90% power to test the null hypothesis of 10% against 30% with 1-sided α of 10%. The Kaplan-Meier method was used to estimate PFS and overall survival (OS). Results: 75 pts were treated in 3 cohorts (Table). Data are as of 1/3/2022. In the TN 2 cohort, the overall response rate (ORR) at EOT was 96% (95% CI: 80-100) and CR with uMRD was 20% (95% CI: 7-41). The ORR for TN 1 and TN 2 combined was 90% (95% CI: 78-97) and CR with uMRD was 24% (95% CI: 13-38). Median follow up was 56 (0-65), 57 (7-63), and 30 (24-35) mos, respectively, for RR, TN 1, and TN 2. There were 3 deaths (RR = 1, TN 1 = 1, TN 2 = 1) and 6 disease progressions (RR = 4, TN 1 = 2, TN 2 = 0). Estimated 48-month PFS for TN 1 and RR cohorts were both 96% (95% CI: 72-99) and OS was 85% (95% CI: 60-95) and 100%, respectively. The estimated 24-month PFS and OS for TN 2 were both 96% (95% CI: 75-99). The most frequent adverse events were neutropenia (95%, 73% grade ≥3), leukopenia (95%, 45% grade ≥3), lymphopenia (93%, 40% grade ≥3), and thrombocytopenia (91%, 28% grade ≥3). The only grade ≥3 non-hematologic toxicity occurring at ≥20% was hypertension (85%, 39% grade ≥3). Atrial fibrillation occurred in 11% of pts. Conclusions: At extended follow-up, remissions remain durable after fixed duration OBIN, IBR, and VEN. The efficacy and acceptable safety justify further study and are being compared to IBR and OBIN in 2 phase 3 US cooperative group trials. Clinical trial information: NCT02427451. [Table: see text]
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Clonal hematopoiesis of indeterminate potential in the companion dog. Leukemia 2022; 36:1401-1403. [PMID: 35145204 DOI: 10.1038/s41375-022-01520-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/19/2022] [Accepted: 01/31/2022] [Indexed: 11/09/2022]
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LC-FACSeq is a method for detecting rare clones in leukemia. JCI Insight 2020; 5:134973. [PMID: 32554930 DOI: 10.1172/jci.insight.134973] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 05/06/2020] [Indexed: 01/07/2023] Open
Abstract
Detecting, characterizing, and monitoring rare populations of cells can increase testing sensitivity, give insight into disease mechanism, and inform clinical decision making. One area that can benefit from increased resolution is management of cancers in clinical remission but with measurable residual disease (MRD) by multicolor FACS. Detecting and monitoring genomic clonal resistance to treatment in the setting of MRD is technically difficult and resource intensive due to the limited amounts of disease cells. Here, we describe limited-cell FACS sequencing (LC-FACSeq), a reproducible, highly sensitive method of characterizing clonal evolution in rare cells relevant to different types of acute and chronic leukemias. We demonstrate the utility of LC-FACSeq for broad multigene gene panels and its application for monitoring sequential acquisition of mutations conferring therapy resistance and clonal evolution in long-term ibrutinib treatment of patients with chronic lymphocytic leukemia. This technique is generalizable for monitoring of other blood and marrow infiltrating cancers.
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Novel BCL2 mutations in venetoclax-resistant, ibrutinib-resistant CLL patients with BTK/PLCG2 mutations. Blood 2020; 135:2192-2195. [PMID: 32232486 PMCID: PMC7290091 DOI: 10.1182/blood.2019003722] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Lucas et al explored the clonal dynamics of chronic lymphocytic leukemia (CLL) patients following treatment and subsequent acquired resistance to ibrutinib and then venetoclax. They report different patterns of resistance mutations from previously reported changes following venetoclax treatment in the absence of prior BTK inhibitor therapy.
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Durable Molecular Remissions in Chronic Lymphocytic Leukemia Treated With CD19-Specific Chimeric Antigen Receptor-Modified T Cells After Failure of Ibrutinib. J Clin Oncol 2017; 35:3010-3020. [PMID: 28715249 DOI: 10.1200/jco.2017.72.8519] [Citation(s) in RCA: 470] [Impact Index Per Article: 67.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Purpose We evaluated the safety and feasibility of anti-CD19 chimeric antigen receptor-modified T (CAR-T) cell therapy in patients with chronic lymphocytic leukemia (CLL) who had previously received ibrutinib. Methods Twenty-four patients with CLL received lymphodepleting chemotherapy and anti-CD19 CAR-T cells at one of three dose levels (2 × 105, 2 × 106, or 2 × 107 CAR-T cells/kg). Nineteen patients experienced disease progression while receiving ibrutinib, three were ibrutinib intolerant, and two did not experience progression while receiving ibrutinib. Six patients were venetoclax refractory, and 23 had a complex karyotype and/or 17p deletion. Results Four weeks after CAR-T cell infusion, the overall response rate (complete response [CR] and/or partial response [PR]) by International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria was 71% (17 of 24). Twenty patients (83%) developed cytokine release syndrome, and eight (33%) developed neurotoxicity, which was reversible in all but one patient with a fatal outcome. Twenty of 24 patients received cyclophosphamide and fludarabine lymphodepletion and CD19 CAR-T cells at or below the maximum tolerated dose (≤ 2 × 106 CAR-T cells/kg). In 19 of these patients who were restaged, the overall response rate by IWCLL imaging criteria 4 weeks after infusion was 74% (CR, 4/19, 21%; PR, 10/19, 53%), and 15/17 patients (88%) with marrow disease before CAR-T cells had no disease by flow cytometry after CAR-T cells. Twelve of these patients underwent deep IGH sequencing, and seven (58%) had no malignant IGH sequences detected in marrow. Absence of the malignant IGH clone in marrow of patients with CLL who responded by IWCLL criteria was associated with 100% progression-free survival and overall survival (median 6.6 months follow-up) after CAR-T cell immunotherapy. The progression-free survival was similar in patients with lymph node PR or CR by IWCLL criteria. Conclusion CD19 CAR-T cells are highly effective in high-risk patients with CLL after they experience treatment failure with ibrutinib therapy.
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Abstract
Purpose Therapeutic targeting of Bruton tyrosine kinase (BTK) with ibrutinib in chronic lymphocytic leukemia has led to a paradigm shift in therapy, and relapse has been uncommon with current follow-up. Acquired mutations in BTK and PLCG2 can cause relapse, but data regarding the prevalence and natural history of these mutations are limited. Patients and Methods Patients accrued to four sequential studies of ibrutinib were included in these analyses. Deep sequencing for BTK and PLCG2 was performed retrospectively on patients who experienced relapse and prospectively on a screening population. Results With a median follow-up time of 3.4 years, the estimated cumulative incidence of progression at 4 years is 19% (95% CI, 14% to 24%). Baseline karyotypic complexity, presence of del(17)(p13.1), and age less than 65 years were risk factors for progression. Among patients who experienced relapse, acquired mutations of BTK or PLCG2 were found in 85% (95% CI, 71% to 94%), and these mutations were detected an estimated median of 9.3 months (95% CI, 7.6 to 11.7 months) before relapse. Of a group of 112 patients examined prospectively, eight patients have experienced relapse, and all of these patients had acquired resistance mutations before relapse. A resistance mutation was detected in an additional eight patients who have not yet met criteria for clinical relapse. Conclusion Relapse of chronic lymphocytic leukemia after ibrutinib is an issue of increasing clinical significance. We show that mutations in BTK and PLCG2 appear early and have the potential to be used as a biomarker for future relapse, suggesting an opportunity for intervention.
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De novo CD5+ diffuse large B-cell lymphoma: Adverse outcomes with and without stem cell transplantation in a large, multicenter, rituximab treated cohort. Am J Hematol 2016; 91:395-9. [PMID: 26800311 DOI: 10.1002/ajh.24299] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/04/2016] [Accepted: 01/06/2016] [Indexed: 12/14/2022]
Abstract
De novo CD5+ diffuse large B-cell lymphomas (DLBCL) are a distinct subgroup of DLBCL with poor prognosis. However the role of rituximab-containing therapy and salvage stem cell transplantation in this patients' population remain to be defined. We retrospectively reviewed clinical features and outcomes of 102 patients with de novo CD5+ DLBCL treated with rituximab-containing therapy at nine different institutions. By Hans' criteria, 64 patients had activated B-cell (ABC) subtype, 24 germinal center B-cell (GCB) subtype, and 14 were not evaluated. No patients had a myc translocation. Eighty-three patients were treated with rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP), 7 with rituximab, etoposide, cyclophosphamide, doxorubicin, vincristine, prednisone (R-EPOCH), and 6 with R-CHOP with methotrexate, 3 g/m(2) . The overall response rate to front-line therapy was 85%. The 3-year progression free survival (PFS) and overall survival (OS) for all patients were 40 and 65%, respectively. The 3-year PFS for ABC- and GCB-subtypes was 34 and 45%, respectively. The 3-year OS for ABC- and GCB-subtypes was 62 and 67%, respectively. The median time to second treatment failure was 3 months and 1 month for ABC- and GCB-subtypes, respectively. Twenty of 28 (71%) transplanted patients with autologous, allogeneic, or both, relapsed. This study confirms the poor prognosis of de novo CD5+ DLBCL in a large multi-center cohort despite initial rituximab-containing chemotherapy and suggests that stem cell transplantation fails to salvage the majority of these patients. Approaches to prevent recurrence and/or novel therapies for relapsed disease are needed for this subgroup of DLBCL patients.
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Etiology of Ibrutinib Therapy Discontinuation and Outcomes in Patients With Chronic Lymphocytic Leukemia. JAMA Oncol 2016; 1:80-7. [PMID: 26182309 DOI: 10.1001/jamaoncol.2014.218] [Citation(s) in RCA: 443] [Impact Index Per Article: 55.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
IMPORTANCE The Bruton tyrosine kinase (BTK) inhibitor ibrutinib is effective in patients with chronic lymphocytic leukemia (CLL). Reasons for discontinuing therapy with this drug and outcomes following discontinuation have not been evaluated outside of clinical trials with relatively short follow-up. OBJECTIVE To determine features associated with discontinuation of ibrutinib therapy and outcomes. DESIGN, SETTING, AND PARTICIPANTS A total of 308 patients participating in 4 sequential trials of ibrutinib at The Ohio State University Comprehensive Cancer Center were included. These clinical trials accrued patients included in this analysis from May 2010 until April 2014, and data were locked in June 2014. MAIN OUTCOMES AND MEASURES Patients were evaluated for time to therapy discontinuation, reasons for discontinuation, and survival following discontinuation. For patients who discontinued therapy because of disease progression, targeted deep sequencing was performed in samples at baseline and time of relapse. RESULTS With a median follow-up of 20 months, 232 patients remained on therapy, 31 had discontinued because of disease progression, and 45 had discontinued for other reasons. Disease progression includes Richter's transformation (RT) or progressive CLL. Richter's transformation appeared to occur early and CLL progressions later (cumulative incidence at 12 months, 4.5% [95% CI, 2.0%-7.0%] and 0.3% [95% CI, 0%-1.0%], respectively). Median survival following RT was 3.5 months (95% CI, 0.3-6.0 months) and 17.6 months (95% CI, 4.7 months-"not reached") following CLL progression. Sequencing on peripheral blood from 8 patients with RT revealed 2 with mutations in BTK, and a lymph node sample showed no mutations in BTK or PLCG2. Deep sequencing on 11 patients with CLL progression revealed BTK or PLCG2 mutations in all. These mutations were not identified before treatment in any patient. CONCLUSIONS AND RELEVANCE This single-institution experience with ibrutinib confirms it to be an effective therapy and identifies, for the first time, baseline factors associated with ibrutinib therapy discontinuation. Outcomes data show poor prognosis after discontinuation, especially for those patients with RT. Finally, sequencing data confirm initial reports associating mutations in BTK and PLCG2 with progression and clearly show that CLL progressions are associated with these mutations, while RT is likely not. TRIAL REGISTRATIONS clinicaltrials.gov Identifiers:NCT01105247, NCT01217749, NCT01589302, and NCT01578707.
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Cytogenetic prioritization with inclusion of molecular markers predicts outcome in previously untreated patients with chronic lymphocytic leukemia treated with fludarabine or fludarabine plus cyclophosphamide: a long-term follow-up study of the US intergroup phase III trial E2997. Leuk Lymphoma 2015; 56:3031-7. [PMID: 25721902 DOI: 10.3109/10428194.2015.1023800] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Fludarabine (F) and cyclophosphamide (C) remain backbones of up-front chemotherapy regimens for chronic lymphocytic leukemia (CLL). We report long-term follow-up of a randomized F vs. FC trial in untreated CLL (#) . With median follow-up of 88 months, estimated median progression-free survival (PFS) was 19.3 vs. 48.1 months for F (n = 109) and FC (n = 118), respectively (p < 0.0001), and median overall survival (OS) was 88.0 vs. 79.1 months (p = 0.96). In multivariable analyses, variables associated with inferior PFS and OS respectively were age (p = 0.002, p < 0.001), Rai stage (p = 0.006, p = 0.02) and sex (p = 0.03, PFS only). Del(17)(p13.1) predicted shorter PFS and OS (p < 0.0001 for each), as did del(11q)(22.3) (p < 0.0001, p = 0.005, respectively), trisomy 12 with mutated Notch1 (p = 0.003, p = 0.03, respectively) and unmutated IGHV (p = 0.009, p = 0.002, respectively), all relative to patients without these features. These data confirm results from shorter follow-up and further justify targeted therapies for CLL.
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Abstract
BACKGROUND Ibrutinib is an irreversible inhibitor of Bruton's tyrosine kinase (BTK) and is effective in chronic lymphocytic leukemia (CLL). Resistance to irreversible kinase inhibitors and resistance associated with BTK inhibition have not been characterized. Although only a small proportion of patients have had a relapse during ibrutinib therapy, an understanding of resistance mechanisms is important. We evaluated patients with relapsed disease to identify mutations that may mediate ibrutinib resistance. METHODS We performed whole-exome sequencing at baseline and the time of relapse on samples from six patients with acquired resistance to ibrutinib therapy. We then performed functional analysis of identified mutations. In addition, we performed Ion Torrent sequencing for identified resistance mutations on samples from nine patients with prolonged lymphocytosis. RESULTS We identified a cysteine-to-serine mutation in BTK at the binding site of ibrutinib in five patients and identified three distinct mutations in PLCγ2 in two patients. Functional analysis showed that the C481S mutation of BTK results in a protein that is only reversibly inhibited by ibrutinib. The R665W and L845F mutations in PLCγ2 are both potentially gain-of-function mutations that lead to autonomous B-cell-receptor activity. These mutations were not found in any of the patients with prolonged lymphocytosis who were taking ibrutinib. CONCLUSIONS Resistance to the irreversible BTK inhibitor ibrutinib often involves mutation of a cysteine residue where ibrutinib binding occurs. This finding, combined with two additional mutations in PLCγ2 that are immediately downstream of BTK, underscores the importance of the B-cell-receptor pathway in the mechanism of action of ibrutinib in CLL. (Funded by the National Cancer Institute and others.).
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MESH Headings
- Adenine/analogs & derivatives
- Agammaglobulinaemia Tyrosine Kinase
- Aged
- Binding Sites/genetics
- Drug Resistance, Neoplasm/genetics
- Exome
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Middle Aged
- Phospholipase C gamma/genetics
- Phospholipase C gamma/metabolism
- Piperidines
- Point Mutation
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Protein-Tyrosine Kinases/genetics
- Pyrazoles/pharmacology
- Pyrazoles/therapeutic use
- Pyrimidines/pharmacology
- Pyrimidines/therapeutic use
- Receptors, Antigen, B-Cell/metabolism
- Recurrence
- Sequence Analysis, DNA
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Association of disease progression on ibrutinib therapy with the acquisition of resistance mutations: A single-center experience of 267 patients. J Clin Oncol 2014. [DOI: 10.1200/jco.2014.32.15_suppl.7010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Characterization of a new chronic lymphocytic leukemia cell line for mechanistic in vitro and in vivo studies relevant to disease. PLoS One 2013; 8:e76607. [PMID: 24130782 PMCID: PMC3793922 DOI: 10.1371/journal.pone.0076607] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 08/26/2013] [Indexed: 12/30/2022] Open
Abstract
Studies of chronic lymphocytic leukemia (CLL) have yielded substantial progress, however a lack of immortalized cell lines representative of the primary disease has hampered a full understanding of disease pathogenesis and development of new treatments. Here we describe a novel CLL cell line (OSU-CLL) generated by EBV transformation, which displays a similar cytogenetic and immunophenotype observed in the patient’s CLL (CD5 positive with trisomy 12 and 19). A companion cell line was also generated from the same patient (OSU-NB). This cell line lacked typical CLL characteristics, and is likely derived from the patient’s normal B cells. In vitro migration assays demonstrated that OSU-CLL exhibits migratory properties similar to primary CLL cells whereas OSU-NB has significantly reduced ability to migrate spontaneously or towards chemokine. Microarray analysis demonstrated distinct gene expression patterns in the two cell lines, including genes on chromosomes 12 and 19, which is consistent with the cytogenetic profile in this cell line. Finally, OSU-CLL was readily transplantable into NOG mice, producing uniform engraftment by three weeks with leukemic cells detectable in the peripheral blood spleen and bone marrow. These studies describe a new CLL cell line that extends currently available models to study gene function in this disease.
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Variations of the ataxia telangiectasia mutated gene in patients with chronic lymphocytic leukemia lack substantial impact on progression-free survival and overall survival: a Cancer and Leukemia Group B study. Leuk Lymphoma 2012; 53:1743-8. [PMID: 22369572 DOI: 10.3109/10428194.2012.668683] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The impact of mutation of the ATM (ataxia telangiectasia mutated) gene in chronic lymphocytic leukemia (CLL) treatment outcome has not been examined. We studied ATM mutations in 73 patients treated with fludarabine and rituximab. ATM gene mutation analysis was performed using temperature gradient capillary electrophoresis. The impact of detected variants on overall survival (OS) and progression-free survival (PFS) was tested with proportional hazards models. None of the 73 patients demonstrated truncating ATM mutations; 17 (23%, 95% confidence interval 14-35%) had non-silent variants (ATM-NSVs), including 13 known ATM polymorphisms and four missense variants. ATM-NSVs were not significantly associated with any baseline characteristics including immunoglobulin heavy chain variable gene (IGVH) status. In multivariable models, no significant differences in complete response (p =0.70), PFS (p =0.59) or OS (p =0.13) were observed. Our data indicate that truncating ATM mutations are rare in patients with CLL. Furthermore, in this dataset, these non-silent variants had limited impact on PFS and OS.
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Tetraspanin CD37 directly mediates transduction of survival and apoptotic signals. Cancer Cell 2012; 21:694-708. [PMID: 22624718 PMCID: PMC3360882 DOI: 10.1016/j.ccr.2012.03.040] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2011] [Revised: 12/13/2011] [Accepted: 03/05/2012] [Indexed: 11/17/2022]
Abstract
Tetraspanins are commonly believed to act only as "molecular facilitators," with no direct role in signal transduction. We herein demonstrate that upon ligation, CD37, a tetraspanin molecule expressed on mature normal and transformed B cells, becomes tyrosine phosphorylated, associates with proximal signaling molecules, and initiates a cascade of events leading to apoptosis. Moreover, we have identified two tyrosine residues with opposing regulatory functions: one lies in the N-terminal domain of CD37 in a predicted "ITIM-like" motif and mediates SHP1-dependent death, whereas the second lies in a predicted "ITAM motif" in the C-terminal domain of CD37 and counteracts death signals by mediating phosphatidylinositol 3-kinase-dependent survival.
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MESH Headings
- Amino Acid Motifs
- Amino Acid Sequence
- Antigens, Neoplasm/chemistry
- Antigens, Neoplasm/genetics
- Antigens, Neoplasm/metabolism
- Apoptosis/drug effects
- Apoptosis Regulatory Proteins/genetics
- Apoptosis Regulatory Proteins/metabolism
- B-Lymphocytes/drug effects
- B-Lymphocytes/metabolism
- B-Lymphocytes/pathology
- Bcl-2-Like Protein 11
- Cell Line, Tumor
- Cell Survival
- Chromatography, Liquid
- Forkhead Box Protein O3
- Forkhead Transcription Factors/metabolism
- HEK293 Cells
- Humans
- Immunoglobulin G/pharmacology
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Membrane Microdomains/metabolism
- Membrane Potential, Mitochondrial
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Molecular Sequence Data
- Nanotechnology
- Phosphatidylinositol 3-Kinase/metabolism
- Phosphorylation
- Protein Transport
- Proteomics/methods
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- RNA Interference
- Recombinant Fusion Proteins/pharmacology
- Signal Transduction/drug effects
- Tandem Mass Spectrometry
- Tetraspanins/chemistry
- Tetraspanins/genetics
- Tetraspanins/metabolism
- Time Factors
- Transfection
- Tyrosine
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Outcome of patients with relapsed or refractory chronic lymphocytic leukemia treated with flavopiridol: impact of genetic features. Leukemia 2012; 26:1442-4. [PMID: 22289993 DOI: 10.1038/leu.2011.375] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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