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1.
Transplant Proc ; 56(2): 380-385, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38368126

ABSTRACT

Loss of microbiota diversity has been clearly associated with poor outcomes in the allogeneic hematopoietic stem cell transplantation setting. However, the choice of the optimal antibiotic prophylaxis during the pre-engraftment phase remains unclear. We designed a prospective randomized study to compare our standard-of-care neutropenia prophylaxis (ciprofloxacin) with rifaximin. We enrolled 38 consecutive adult patients who underwent allogeneic hematopoietic stem cell transplantation setting and were randomly assigned to receive ciprofloxacin (20 patients) or rifaximin (18 patients) at day -1. Pretransplant and transplant characteristics did not differ between groups. Cumulative incidence (CI) of acute graft-vs-host disease grade II to IV and moderate/severe chronic graft-vs-host disease was similar in both groups. With a median follow-up of 13.2 months (range, 6.8-30.2) in surviving patients, the 1-year CI of relapse was 20.8% in ciprofloxacin vs 17.8% in rifaximin (P = .616). Importantly, the 1-year CI of treatment-related mortality was significantly reduced in the ciprofloxacin group (10.2% vs 27.8%, P = .032), leading to higher 1-year overall survival (88.9% vs 74.6%, P = .038). In Cox-regression multivariate analysis, antibiotic prophylaxis remained the only predictor of overall survival, independently of donor type, disease risk index, and moderate/severe chronic graft-vs-host disease. Further studies are needed to assess the effects on microbiota diversity and confirm these outcomes.


Subject(s)
Graft vs Host Disease , Hematopoietic Stem Cell Transplantation , Neutropenia , Adult , Humans , Ciprofloxacin/therapeutic use , Graft vs Host Disease/etiology , Graft vs Host Disease/prevention & control , Hematopoietic Stem Cell Transplantation/adverse effects , Prospective Studies , Rifaximin/adverse effects
2.
Int J Mol Sci ; 24(22)2023 Nov 07.
Article in English | MEDLINE | ID: mdl-38003218

ABSTRACT

Post-transplant lymphoproliferative disease (PTLD) is a fatal complication of hematopoietic cell transplantation (HCT) associated with the Epstein-Barr virus (EBV). Multiple factors such as transplant type, graft-versus-host disease (GVHD), human leukocyte antigens (HLA) mismatch, patient age, and T-lymphocyte-depleting treatments increase the risk of PTLD. EBV reactivation in hematopoietic cell transplant recipients is monitored through periodic quantitative polymerase chain reaction (Q-PCR) tests. However, substantial uncertainty persists regarding the clinically significant EBV levels for these patients. Guidelines recommend initiating EBV monitoring no later than four weeks post-HCT and conducting it weekly. Pre-emptive therapies, such as the reduction of immunosuppressive therapy and the administration of rituximab to treat EBV viral loads are also suggested. In this study, we investigated the occurrence of EBV-PTLD in 546 HCT recipients, focusing on the clinical manifestations and risk factors associated with the disease. We managed to identify 67,150 viral genomic copies/mL as the cutoff point for predicting PTLD, with 80% sensitivity and specificity. Among our cohort, only 1% of the patients presented PTLD. Anti-thymocyte globulin (ATG) and GVHD were independently associated with lower survival rates and higher treatment-related mortality. According to our findings, prophylactic measures including regular monitoring, pre-emptive therapy, and supportive treatment against infections can be effective in preventing EBV-related complications. This study also recommends conducting EBV monitoring at regular intervals, initiating pre-emptive therapy when viral load increases, and identifying factors that increase the risk of PTLD. Our study stresses the importance of frequent and careful follow-ups of post-transplant complications and early intervention in order to improve survival rates and reduce mortality.


Subject(s)
Epstein-Barr Virus Infections , Graft vs Host Disease , Hematopoietic Stem Cell Transplantation , Lymphoproliferative Disorders , Humans , Rituximab/therapeutic use , Herpesvirus 4, Human/physiology , Epstein-Barr Virus Infections/complications , Epstein-Barr Virus Infections/drug therapy , Hematopoietic Stem Cell Transplantation/adverse effects , Incidence , Lymphoproliferative Disorders/drug therapy , Lymphoproliferative Disorders/etiology , Graft vs Host Disease/etiology , Viral Load , DNA, Viral/genetics , Retrospective Studies
3.
EClinicalMedicine ; 65: 102307, 2023 Nov.
Article in English | MEDLINE | ID: mdl-38033506

ABSTRACT

Background: Patients with chronic lymphocytic leukemia (CLL) have a higher risk of developing other malignancies (OMs) compared to the general population. However, the impact of CLL-related risk factors and CLL-directed treatment is still unclear and represents the focus of this work. Methods: We conducted a retrospective international multicenter study to assess the incidence of OMs and detect potential risk factors in 19,705 patients with CLL, small lymphocytic lymphoma, or high-count CLL-like monoclonal B-cell lymphocytosis, diagnosed between 2000 and 2016. Data collection took place between October 2020 and March 2022. Findings: In 129,254 years of follow-up after CLL diagnosis, 3513 OMs were diagnosed (27.2 OMs/1000 person-years). The most common hematological OMs were Richter transformation, myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Non-melanoma skin (NMSC) and prostate cancers were the most common solid tumors (STs).The only predictor for MDS and AML development was treatment with fludarabine and cyclophosphamide with/without rituximab (FC ± R) (OR = 3.7; 95% CI = 2.79-4.91; p < 0.001). STs were more frequent in males and patients with unmutated immunoglobulin heavy variable genes (OR = 1.77; 95% CI = 1.49-2.11; p < 0.001/OR = 1.89; 95% CI = 1.6-2.24; p < 0.001).CLL-directed treatment was associated with non-melanoma skin and prostate cancers (OR = 1.8; 95% CI = 1.36-2.41; p < 0.001/OR = 2.11; 95% CI = 1.12-3.97; p = 0.021). In contrast, breast cancers were more frequent in untreated patients (OR = 0.17; 95% CI = 0.08-0.33; p < 0.001).Patients with CLL and an OM had inferior overall survival (OS) than those without. AML and MDS conferred the worst OS (p < 0.001). Interpretation: OMs in CLL impact on OS. Treatment for CLL increased the risk for AML/MDS, prostate cancer, and NMSC. FCR was associated with increased risk for AML/MDS. Funding: AbbVie, and EU/EFPIAInnovative Medicines Initiative Joint Undertaking HARMONY grant n° 116026.

4.
Am J Hematol ; 98(12): 1856-1868, 2023 12.
Article in English | MEDLINE | ID: mdl-37772428

ABSTRACT

In this retrospective international multicenter study, we describe the clinical characteristics and outcomes of patients with chronic lymphocytic leukemia (CLL) and related disorders (small lymphocytic lymphoma and high-count monoclonal B lymphocytosis) infected by SARS-CoV-2, including the development of post-COVID condition. Data from 1540 patients with CLL infected by SARS-CoV-2 from January 2020 to May 2022 were included in the analysis and assigned to four phases based on cases disposition and SARS-CoV-2 variants emergence. Post-COVID condition was defined according to the WHO criteria. Patients infected during the most recent phases of the pandemic, though carrying a higher comorbidity burden, were less often hospitalized, rarely needed intensive care unit admission, or died compared to patients infected during the initial phases. The 4-month overall survival (OS) improved through the phases, from 68% to 83%, p = .0015. Age, comorbidity, CLL-directed treatment, but not vaccination status, emerged as risk factors for mortality. Among survivors, 6.65% patients had a reinfection, usually milder than the initial one, and 16.5% developed post-COVID condition. The latter was characterized by fatigue, dyspnea, lasting cough, and impaired concentration. Infection severity was the only risk factor for developing post-COVID. The median time to resolution of the post-COVID condition was 4.7 months. OS in patients with CLL improved during the different phases of the pandemic, likely due to the improvement of prophylactic and therapeutic measures against SARS-CoV-2 as well as the emergence of milder variants. However, mortality remained relevant and a significant number of patients developed post-COVID conditions, warranting further investigations.


Subject(s)
COVID-19 , Leukemia, Lymphocytic, Chronic, B-Cell , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , SARS-CoV-2 , Post-Acute COVID-19 Syndrome , Retrospective Studies
5.
Cancers (Basel) ; 15(13)2023 Jul 07.
Article in English | MEDLINE | ID: mdl-37444639

ABSTRACT

(1) Background: Autologous, allogeneic hematopoietic cell transplantation (HCT) and other cellular therapies, including CAR T cell and gene therapy, constitute a cornerstone in the management of various benign and malignant hematological disorders. Invasive fungal infections (IFD) remain a significant cause of morbidity and mortality in HCT recipients. Therefore, we investigated the prevalence and risk factors of IFD following HCT and other cellular therapies in an era of novel antifungal prophylaxis. (2) Methods: In this study, we retrospectively enrolled adult HCT recipients who were treated at our JACIE-accredited center according to standard operating procedures over the last decade (2013-2022). (3) Results: 950 patients who received cellular therapies were studied. None of the 19 CAR T cell and neither of the two gene therapy recipients developed IFD whereas 3/456 autologous HCT recipients who suffered from primary refractory/relapsed lymphomas presented with probable IFD. Overall, 11 patients who received allogeneic HCT experienced probable IFD, possible IFD was found in 31/473, and IFD was proven in 10/473. A second IFD episode was present in three patients. Four-year OS was significantly lower in proven compared to probable IFD (p = 0.041) and was independently associated with HCT-CI (p = 0.040) and chronic GVHD (p = 0.045). (4) Conclusions: In this real-world cohort, the prevalence of proven and probable IFD in an era of novel antifungal prophylaxis was found to be relatively low. However, IFDs were associated with poor outcomes for patients who received allogeneic HCT.

6.
Leuk Lymphoma ; 63(13): 3128-3137, 2022 12.
Article in English | MEDLINE | ID: mdl-36002396

ABSTRACT

Opposing acute lymphoblastic leukemia, sparse data about AYAs with acute myeloid leukemia (AML) is available. Overall, 125 AYAs (age 10-35 years) treated during the last two decades were evaluated and compared to 385 older patients. CBF leukemia was more frequent in AYAs (21.6% vs. 8%, p < 0.001); however, many presented high-risk features. AYAs showed improved complete remission rate (CR, 80% vs. 65%, p = 0.01), lower cumulative incidence of relapse and TRM and longer survival (5 year-OS 53% vs. 24%, p < 0.0001), observed mainly in intermediate-risk karyotype. Adolescents displayed even better outcomes (5 year-OS 69%). AlloHCT in CR1 was beneficial for nonadolescent AYAs (5 year-OS 66.7% vs. 44.4% without HCT, p = 0.04). Among 50 APL patients, 19 AYAs experienced better outcomes than older, mainly attributed to reduced treatment-related mortality (TRM, 5% vs. 19%, p = 0.1). We observed an important (>10%) survival gain for AYAs during the last decade. However, AYAs have still unmet needs to obtain optimal cure rates.


Subject(s)
Hematopoietic Stem Cell Transplantation , Leukemia, Myeloid, Acute , Precursor Cell Lymphoblastic Leukemia-Lymphoma , Adolescent , Young Adult , Humans , Child , Adult , Leukemia, Myeloid, Acute/diagnosis , Leukemia, Myeloid, Acute/epidemiology , Leukemia, Myeloid, Acute/therapy , Remission Induction , Precursor Cell Lymphoblastic Leukemia-Lymphoma/therapy , Age Factors , Retrospective Studies
7.
Front Oncol ; 11: 788761, 2021.
Article in English | MEDLINE | ID: mdl-34912723

ABSTRACT

Several reports highlight the clinical significance of cytogenetic complexity, namely, complex karyotype (CK) identified though the performance of chromosome banding analysis (CBA) in chronic lymphocytic leukemia. Indeed, apart from a number of studies underscoring the prognostic and predictive value of CK in the chemo(immune)therapy era, mounting evidence suggests that CK could serve as an independent prognosticator and predictor even in patients treated with novel agents. In the present review, we provide an overview of the current knowledge regarding the clinical impact of CK in CLL, touching upon open issues related to the incorporation of CK in the clinical setting.

8.
Leukemia ; 35(12): 3444-3454, 2021 12.
Article in English | MEDLINE | ID: mdl-34725454

ABSTRACT

Patients with chronic lymphocytic leukemia (CLL) may be more susceptible to Coronavirus disease 2019 (COVID-19) due to age, disease, and treatment-related immunosuppression. We aimed to assess risk factors of outcome and elucidate the impact of CLL-directed treatments on the course of COVID-19. We conducted a retrospective, international study, collectively including 941 patients with CLL and confirmed COVID-19. Data from the beginning of the pandemic until March 16, 2021, were collected from 91 centers. The risk factors of case fatality rate (CFR), disease severity, and overall survival (OS) were investigated. OS analysis was restricted to patients with severe COVID-19 (definition: hospitalization with need of oxygen or admission into an intensive care unit). CFR in patients with severe COVID-19 was 38.4%. OS was inferior for patients in all treatment categories compared to untreated (p < 0.001). Untreated patients had a lower risk of death (HR = 0.54, 95% CI:0.41-0.72). The risk of death was higher for older patients and those suffering from cardiac failure (HR = 1.03, 95% CI:1.02-1.04; HR = 1.79, 95% CI:1.04-3.07, respectively). Age, CLL-directed treatment, and cardiac failure were significant risk factors of OS. Untreated patients had a better chance of survival than those on treatment or recently treated.


Subject(s)
COVID-19/complications , COVID-19/mortality , Leukemia, Lymphocytic, Chronic, B-Cell/complications , Leukemia, Lymphocytic, Chronic, B-Cell/mortality , COVID-19/diagnosis , COVID-19/virology , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/therapy , Leukemia, Lymphocytic, Chronic, B-Cell/virology , Mortality , Prognosis , Risk Factors , SARS-CoV-2 , Severity of Illness Index , Survival Analysis
9.
J Clin Med ; 10(10)2021 May 11.
Article in English | MEDLINE | ID: mdl-34064671

ABSTRACT

BACKGROUND: Myeloid-derived suppressor cells (MDSCs) are implicated in the complex interplay involving graft-versus-leukemia (GVL) effects and graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HCT) in hematologic malignancies. METHODS: A review of literature through PubMed was undertaken to summarize the published evidence on the pathophysiology and clinical implications of MDSCs in allo-HCT. Literature sources published in English since 1978 were searched, using the terms Natural Suppressor (NS) cells, MDSCs, GVHD, and allo-HCT. RESULTS: In vivo studies demonstrated that MDSCs derived from mobilization protocols could strongly suppress allo-responses mediated by T cells and enhance T-Reg activity, thus inhibiting GVHD toxicity. However, the influence of MDSCs on the GVL effect is not fully defined. CONCLUSIONS: The induction or maintenance of MDSC suppressive function would be advantageous in suppressing inflammation associated with GVHD. Pathways involved in MDSC metabolism and the inflammasome signaling are a promising field of study to elucidate the function of MDSCs in the pathogenesis of GVHD and translate these findings to a clinical setting.

10.
Front Oncol ; 10: 1226, 2020.
Article in English | MEDLINE | ID: mdl-32850364

ABSTRACT

The polycomb repressive complex 2 (PRC2) maintains the transcriptional repression of target genes through its catalytic component enhancer of zeste homolog 2 (EZH2). Through modulating critical gene expression, EZH2 also plays a role in cancer development and progression by promoting cancer cell survival and invasion. Mutations in EZH2 are prevalent in certain B-cell lymphoma subtypes such as diffuse large cell lymphoma and follicular lymphoma; while no EZH2 mutation has been reported in the mantle cell lymphoma (MCL). Here we demonstrate that the PRC2 components EZH2, EED and SUZ12 are upregulated in the MCL cells as compared to normal B-cells. Moreover, stably transfected cells with wild-type EZH2 or-EED showed increased cell growth and H3K27-trimehtylation. However, unlike wild-type EZH2, ectopic expression of a deletion construct of EZH2 (EZH2Δ550-738 lacking SET domain) had no growth advantage over control cells. Pharmacological inhibition of EZH2 suppressed H3K27me3 and had significant inhibitory effect on cell growth and colony forming capacity (p < 0.05) of MCL cells, and this effect was more or less comparable to the anti-proliferative effects of EZH2 inhibition in cells harboring EZH2-mutation. Mechanistically, EZH2 appears to downregulate expression of cdkn2b gene via enhanced H3K27me3, a well-known suppressive epigenetic mark, at the cdkn2b promoter region. Overall, these results highlight that deregulation of PRC2/EZH2 is associated with epigenetic suppression of cdkn2b in MCL, and in part responsible for increased cell growth, thus the EZH2 inhibitors may have therapeutic potential in the patients with MCL.

11.
Front Med (Lausanne) ; 7: 608165, 2020.
Article in English | MEDLINE | ID: mdl-33614674

ABSTRACT

Objectives: Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-Kp) emerge as a major healthcare concern worldwide. Despite the significance of infections before and after allogeneic hematopoietic cell transplantation (alloHCT), the burden of KP infections has not been extensively evaluated. Methods: We studied the incidence, risk factors, and outcomes of consecutive alloHCT recipients with Kp isolates before and after alloHCT. Results: Among 424 patients who underwent alloHCT in 2008-2018, we studied two groups: those with Kp isolates before (group 1, 52 patients) and those with Kp isolates after alloHCT (group 2, 66 patients). prE-transplant infections were associated with post-transplant infections (p = 0.010), despite secondary prophylaxis. KPC-Kp was isolated in 29% of group 1, and 80% of group 2. Both groups were characterized by a significant burden of moderate-severe acute graft- vs.-host disease (GVHD) [cumulative incidence (CI) of 44.5 and 61.9%, respectively] and severe chronic (CI of 56.7 and 61.9%). Kp infections and GVHD were independent predictive factors of treatment-related mortality (TRM) in both groups. Conclusions: Our study highlights the significant impact of Kp infections on TRM, with GVHD consisting an important underlying factor. As prophylactic measures did not improve rates of post-transplant infections, innovative interventions need to be further investigated to address this major healthcare concern.

12.
Hematology ; 24(1): 426-438, 2019 Dec.
Article in English | MEDLINE | ID: mdl-30947625

ABSTRACT

OBJECTIVES: Beta-thalassemias are a group of recessively autosomal inherited disorders of hemoglobin synthesis, which, due to mutations of the beta-globin gene, lead to various degrees of defective beta-chain production, an imbalance in alpha/beta-globin chain synthesis, ineffective erythropoiesis, and anemia. Improved survival in thalassemic patients has led to the emergence of previously unrecognized complications, such as renal disease. METHODS: A comprehensive literature review through PubMed was undertaken to summarize the published evidence on the epidemiology and pathophysiology of renal disease in thalassemia. Literature sources published in English since 1990 were searched, using the terms beta-thalassemia, renal disease. RESULTS: Renal disease is considered to be the 4th cause of morbidity among patients with transfusion dependent thalassemia. Chronic anemia, hypoxia and iron overload are the main mechanisms implicated in development of renal injury, whereas several studies also suggested a contributive role of iron chelators. DISCUSSION AND CONCLUSION: Kidney disease may develop through progressive renal tubular and glomerular damage; thus, its early recognition is important in order to prevent and/or reverse deterioration. This review will provide an insight on the involved mechanisms implicated in kidney disease in thalassemic patients and will discuss the updates on diagnosis and prevention of renal complications in thalassemia.


Subject(s)
Hypoxia , Iron Overload , Kidney Diseases , beta-Thalassemia , Female , Humans , Hypoxia/complications , Hypoxia/metabolism , Hypoxia/mortality , Hypoxia/therapy , Iron Overload/complications , Iron Overload/metabolism , Iron Overload/mortality , Iron Overload/therapy , Kidney Diseases/etiology , Kidney Diseases/metabolism , Kidney Diseases/mortality , Kidney Diseases/therapy , Male , beta-Thalassemia/complications , beta-Thalassemia/metabolism , beta-Thalassemia/mortality , beta-Thalassemia/therapy
13.
Curr Probl Cancer ; 43(3): 222-227, 2019 06.
Article in English | MEDLINE | ID: mdl-29895435

ABSTRACT

Blinatumomab, a bispecific T-cell engager antibody construct targeting CD19, has been shown to improve the outcome in patients with relapsed and/or refractory B-cell acute lymphoblastic leukemia. Treatment with blinatumomab demonstrated significant survival benefit over chemotherapy, supporting its use as a bridge therapy to allogeneic hematopoietic stem cell transplantation. Unfortunately, following initial response, approximately 50% of responding patients eventually relapse. At the time of failure, the majority of patients have CD19-positive blasts, yet a concerning number of CD19-negative relapses has been reported. In the data reported herein, we present an interesting case of a 42-year-old patient with primary refractory B-cell acute lymphoblastic leukemia who achieved complete morphologic remission after one cycle of blinatumomab as a single agent. Notably, and in the absence of extramedullary disease history, the response in marrow coincided with the emergence of CD19-positive extramedullary relapse including sites of previous punctures for blood and bone marrow samples, as confirmed by biopsy, as well as parenchymal organs (eg breast and lung). During the second cycle of blinatumomab, a CD19-negative morphological relapse emerged. The loss of CD19 was a transient event, as leukemic cells partially regained it after chemotherapy. This study illustrates a challenging situation of relapsed and refractory acute lymphoblastic leukemia complicated with extramedullary disease after exposure to a bispecific T-cell engager antibody, such as blinatumomab. Physicians should maintain a high level of suspicion for the evolution of extramedullary leukemia. This pattern of resistance and/or relapse to blinatumomab resembles the graft-versus-leukemia effect after allogeneic transplantation (stronger in blood and marrow than in other tissues). Mechanisms of resistance to blinatumomab are not yet clear. Combination treatments for refractory patients and those at high risk for exramedullary disease may warrant future assessment.


Subject(s)
Antibodies, Bispecific/therapeutic use , Antigens, CD19/metabolism , Bone Marrow/drug effects , Drug Resistance, Neoplasm , Neoplasm Recurrence, Local/drug therapy , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Adult , Antineoplastic Agents/therapeutic use , Bone Marrow/metabolism , Bone Marrow/pathology , Female , Humans , Neoplasm Recurrence, Local/metabolism , Neoplasm Recurrence, Local/pathology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology , Prognosis , Remission Induction
15.
J Med Chem ; 60(19): 8131-8144, 2017 10 12.
Article in English | MEDLINE | ID: mdl-28858511

ABSTRACT

The cellular delivery of nucleotides through various pronucleotide strategies has expanded the utility of nucleosides as a therapeutic class. Although highly successful, the highly popular ProTide system relies on a four-step enzymatic and chemical process to liberate the corresponding monophosphate. To broaden the scope and reduce the number of steps required for monophosphate release, we have developed a strategy that depends on initial chemical activation by a sulfur atom of a methylthioalkyl protecting group, followed by enzymatic hydrolysis of the resulting phosphoramidate monoester. We have employed this ProTide strategy for intracellular delivery of a nucleotide antagonist of eIF4E in mantle cell lymphoma (MCL) cells. Furthermore, we demonstrated that chemical inhibition of cap-dependent translation results in suppression of c-Myc expression, increased p27 expression, and enhanced chemosensitization to doxorubicin, dexamethasone, and ibrutinib. In addition, the new ProTide strategy was shown to enhance oral bioavailability of the corresponding monoester phosphoramidate.


Subject(s)
Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Lymphoma, Mantle-Cell/drug therapy , Nuclear Cap-Binding Protein Complex/drug effects , Peptides/chemical synthesis , Peptides/pharmacology , Animals , Antineoplastic Agents/pharmacokinetics , Cell Line, Tumor , Cell Survival/drug effects , Cyclin-Dependent Kinase Inhibitor p27/antagonists & inhibitors , Cyclin-Dependent Kinase Inhibitor p27/biosynthesis , Drug Design , Eukaryotic Initiation Factor-4E/antagonists & inhibitors , Female , Humans , Lymphoma, Mantle-Cell/pathology , Proto-Oncogene Proteins c-myc/antagonists & inhibitors , Rats , Rats, Sprague-Dawley
16.
Oncotarget ; 6(42): 44703-13, 2015 Dec 29.
Article in English | MEDLINE | ID: mdl-26565811

ABSTRACT

PTPN6 (SHP1) is a tyrosine phosphatase that negatively controls the activity of multiple signaling pathways including STAT signaling, however role of mutated PTPN6 is not much known. Here we investigated whether PTPN6 might also be a potential target for diffuse large B cell lymphoma (DLBCL) and performed Sanger sequencing of the PTPN6 gene. We have identified missense mutations within PTPN6 (N225K and A550V) in 5% (2/38) of DLBCL tumors. Site directed mutagenesis was performed to mutate wild type (WT) PTPN6 and stable cell lines were generated by lentiviral transduction of PTPN6(WT), PTPN6(N225K) and PTPN6(A550V) constructs, and effects of WT or mutated PTPN6 on STAT3 signaling were analyzed. WT PTPN6 dephosphorylated STAT3, but had no effect on STAT1, STAT5 or STAT6 phosphorylation. Both PTPN6 mutants were unable to inhibit constitutive, as well as cytokines induced STAT3 activation. Both PTPN6 mutants also demonstrated reduced tyrosine phosphatase activity and exhibited enhanced STAT3 transactivation activity. Intriguingly, a lack of direct binding between STAT3 and WT or mutated PTPN6 was observed. However, compared to WT PTPN6, cells expressing PTPN6 mutants exhibited increased binding between JAK3 and PTPN6 suggesting a more dynamic interaction of PTPN6 with upstream regulators of STAT3. Consistent with this notion, both the mutants demonstrated increased resistance to JAK3 inhibitor, WHIP-154 relative to WT PTPN6. Overall, this is the first study, which demonstrates that N225K and A550V PTPN6 mutations cause loss-of-function leading to JAK3 mediated deregulation of STAT3 pathway and uncovers a mechanism that tumor cells can use to control PTPN6 substrate specificity.


Subject(s)
Janus Kinase 3/metabolism , Lymphoma, Large B-Cell, Diffuse/enzymology , Lymphoma, Large B-Cell, Diffuse/genetics , Mutation, Missense , Protein Tyrosine Phosphatase, Non-Receptor Type 6/genetics , STAT3 Transcription Factor/metabolism , Antineoplastic Agents/pharmacology , Drug Resistance, Neoplasm , Gene Expression Regulation, Enzymologic , Gene Expression Regulation, Neoplastic , HEK293 Cells , Humans , Janus Kinase 3/antagonists & inhibitors , Janus Kinase 3/genetics , Lymphoma, Large B-Cell, Diffuse/drug therapy , Lymphoma, Large B-Cell, Diffuse/pathology , Mutagenesis, Site-Directed , Phosphorylation , Protein Binding , Protein Kinase Inhibitors/pharmacology , Protein Tyrosine Phosphatase, Non-Receptor Type 6/metabolism , STAT3 Transcription Factor/genetics , Signal Transduction , Substrate Specificity , Transfection
17.
Oncotarget ; 6(11): 9488-501, 2015 Apr 20.
Article in English | MEDLINE | ID: mdl-25839159

ABSTRACT

Deregulated mRNA translation has been implicated in disease development and in part is controlled by a eukaryotic initiation complex eIF4F (composed of eIF4E, eIF4G and eIF4A). We demonstrate here that the cap bound fraction from lymphoma cells was enriched with eIF4G and eIF4E indicating that lymphoma cells exist in an activated translational state. Moreover, 77% (110/142) of diffuse large B cell lymphoma tumors expressed eIF4E and this was associated with an inferior event free survival. Over-expression of wild-type eIF4E (eIF4E(WT)) but not cap-mutant eIF4E (eIF4E(cap mutant)) increased the activation of the eIF4F complex. Treatment with the active-site dual mTOR inhibitor CC214-1 reduced the level of the eIF4F complex by decreasing the cap bound fraction of eIF4G and increasing the levels of 4E-BP1. CC214-1 inhibited both the cap dependent and global protein translation. CC214-1 inhibited c-Myc, and cyclin D3 translation by decreasing polysomal fractions from lymphoma cells. Inhibition of eIF4E with shRNA further decreased the CC214-1 induced inhibition of the eIF4F complex, c-Myc, cyclin D3 translation, and colony formation. These studies demonstrate that the eIF4F complex is deregulated in aggressive lymphoma and that dual mTOR therapy has therapeutic potential in these patients.


Subject(s)
Eukaryotic Initiation Factor-4F/antagonists & inhibitors , Gene Expression Regulation, Neoplastic , Imidazoles/pharmacology , Lymphoma, Large B-Cell, Diffuse/genetics , Molecular Targeted Therapy , Neoplasm Proteins/physiology , Protein Biosynthesis , Protein Kinase Inhibitors/pharmacology , Pyrazines/pharmacology , RNA Caps/metabolism , RNA, Neoplasm/metabolism , TOR Serine-Threonine Kinases/antagonists & inhibitors , Adaptor Proteins, Signal Transducing/metabolism , Cell Cycle Proteins , Cell Line, Tumor , Cyclin D3/biosynthesis , Cyclin D3/genetics , Eukaryotic Initiation Factor-4E/analysis , Eukaryotic Initiation Factor-4F/physiology , Eukaryotic Initiation Factor-4G/analysis , HEK293 Cells , Humans , Lymphoma, Large B-Cell, Diffuse/drug therapy , Lymphoma, Large B-Cell, Diffuse/enzymology , Neoplasm Invasiveness , Neoplasm Proteins/analysis , Neoplasm Proteins/antagonists & inhibitors , Phosphoproteins/metabolism , Phosphorylation/drug effects , Protein Processing, Post-Translational/drug effects , Proto-Oncogene Proteins c-myc/biosynthesis , Proto-Oncogene Proteins c-myc/genetics , RNA Interference , RNA, Neoplasm/genetics , RNA, Small Interfering/genetics , Tumor Stem Cell Assay
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