ABSTRACT
Merkel cell carcinoma (MCC) is a rare aggressive cutaneous neuroendocrine malignancy with a mortality rate of around 33%. The presence of advanced disease at the time of diagnosis is associated with poor prognosis. Twofold etiologies have been described in the pathogenesis of Merkel cell carcinoma: chronic exposure to ultraviolet (UV) light and Merkel cell polyomavirus (MCPvY). MCC usually affects sun-exposed skin areas, and the presence of cutaneous nodules is the hallmark of the disease. However, there have been case reports in the literature where the diagnosis of MCC was made in the absence of any cutaneous findings. We present a case report of Merkel cell carcinoma that is unique in its presentation because of the presence of pulmonary and hepatic nodules and the absence of cutaneous lesions.
ABSTRACT
The goal of therapy for patients with essential thrombocythemia (ET) and polycythemia vera (PV) is to reduce thrombotic events by normalizing blood counts. Hydroxyurea (HU) and interferon-α (IFN-α) are the most frequently used cytoreductive options for patients with ET and PV at high risk for vascular complications. Myeloproliferative Disorders Research Consortium 112 was an investigator-initiated, phase 3 trial comparing HU to pegylated IFN-α (PEG) in treatment-naïve, high-risk patients with ET/PV. The primary endpoint was complete response (CR) rate at 12 months. A total of 168 patients were treated for a median of 81.0 weeks. CR for HU was 37% and 35% for PEG (P = .80) at 12 months. At 24 to 36 months, CR was 20% to 17% for HU and 29% to 33% for PEG. PEG led to a greater reduction in JAK2V617F at 24 months, but histopathologic responses were more frequent with HU. Thrombotic events and disease progression were infrequent in both arms, whereas grade 3/4 adverse events were more frequent with PEG (46% vs 28%). At 12 months of treatment, there was no significant difference in CR rates between HU and PEG. This study indicates that PEG and HU are both effective treatments for PV and ET. With longer treatment, PEG was more effective in normalizing blood counts and reducing driver mutation burden, whereas HU produced more histopathologic responses. Despite these differences, both agents did not differ in limiting thrombotic events and disease progression in high-risk patients with ET/PV. This trial was registered at www.clinicaltrials.gov as #NCT01259856.
Subject(s)
Polycythemia Vera , Thrombocythemia, Essential , Thrombosis , Disease Progression , Humans , Hydroxyurea/adverse effects , Interferon-alpha/adverse effects , Polycythemia Vera/drug therapy , Polycythemia Vera/genetics , Thrombocythemia, Essential/drug therapy , Thrombocythemia, Essential/genetics , Thrombosis/chemically induced , Thrombosis/prevention & controlABSTRACT
We evaluated the feasibility of ruxolitinib therapy followed by a reduced-intensity conditioning (RIC) regimen for patients with myelofibrosis (MF) undergoing transplantation in a 2-stage Simon phase II trial. The aims were to decrease the incidence of graft failure (GF) and nonrelapse mortality (NRM) compared with data from the previous Myeloproliferative Disorders Research Consortium 101 Study. The plan was to enroll 11 patients each in related donor (RD) and unrelated donor (URD) arms, with trial termination if ≥3 failures (GF or death by day +100 post-transplant) occurred in the RD arm or ≥6 failures occurred in the URD. A total of 21 patients were enrolled, including 7 in the RD arm and 14 in the URD arm. The RD arm did not meet the predetermined criteria for proceeding to stage II. Although the URD arm met the criteria for stage II, the study was terminated owing to poor accrual and a significant number of failures. In all 19 transplant recipients, ruxolitinib was tapered successfully without significant side effects, and 9 patients (47%) had a significant decrease in symptom burden. The cumulative incidences of GF, NRM, acute graft-versus-host disease (GVHD), and chronic GVHD at 24 months were 16%, 28%, 64%, and 76%, respectively. On an intention-to-treat basis, the 2-year overall survival was 61% for the RD arm and 70% for the URD arm. Ruxolitinib can be integrated as pretransplantation treatment for patients with MF, and a tapering strategy before transplantation is safe, allowing patients to commence conditioning therapy with a reduced symptom burden. However, GF and NRM remain significant.
Subject(s)
Graft vs Host Disease/mortality , Hematopoietic Stem Cell Transplantation , Primary Myelofibrosis/mortality , Primary Myelofibrosis/therapy , Pyrazoles/administration & dosage , Transplantation Conditioning , Unrelated Donors , Acute Disease , Adult , Aged , Chronic Disease , Disease-Free Survival , Female , Graft vs Host Disease/etiology , Humans , Incidence , Male , Middle Aged , Myeloproliferative Disorders , Nitriles , Pyrimidines , Survival Rate , Transplantation, HomologousABSTRACT
Myeloproliferative neoplasms (MPN), including polycythemia vera, essential thrombocythemia, and primary myelofibrosis, have a propensity to evolve into accelerated and blast-phase disease (MPN-AP/BP), carrying a dismal prognosis. Conventional antileukemia therapy has limited efficacy in this setting. Thus, MPN-AP/BP is an urgent unmet clinical need. Modest responses to hypomethylating agents and single-agent ruxolitinib have been reported. More recently, combination of ruxolitinib and decitabine has demonstrated synergistic in vitro activity in human and murine systems. These observations led us to conduct a phase 1 study to explore the safety of combined decitabine and dose-escalated ruxolitinib in patients with MPN-AP/BP. A total of 21 patients were accrued to this multicenter study. Ruxolitinib was administered at doses of 10, 15, 25, or 50 mg twice daily in combination with decitabine (20 mg/m2 per day for 5 days) in 28-day cycles. The maximum tolerated dose was not reached. The most common reasons for study discontinuation were toxicity/adverse events (37%) and disease progression (21%). Fourteen patients died during study treatment period or follow-up. The median overall survival for patients on study was 7.9 months (95% confidence interval, 4.1-not reached). Among evaluable patients, the overall response rate by protocol-defined criteria (complete remission with incomplete count recovery + partial remission) was 9/17 (53%) and by intention-to-treat analysis was 9/21 (42.9%). The combination of decitabine and ruxolitinib was generally well tolerated by patients with MPN-AP/BP and demonstrates potentially promising clinical activity. A phase 2 trial evaluating the efficacy of this combination regimen is ongoing within the Myeloproliferative Disorder Research Consortium.
Subject(s)
Antineoplastic Agents/therapeutic use , Decitabine/therapeutic use , Myeloproliferative Disorders/drug therapy , Pyrazoles/therapeutic use , Aged , Antineoplastic Agents/adverse effects , Antineoplastic Agents/pharmacokinetics , Blast Crisis , Decitabine/adverse effects , Decitabine/pharmacokinetics , Dose-Response Relationship, Drug , Drug Administration Schedule , Drug Therapy, Combination , Female , Half-Life , Hematologic Diseases/etiology , Humans , Male , Middle Aged , Myeloproliferative Disorders/pathology , Nitriles , Pyrazoles/adverse effects , Pyrazoles/pharmacokinetics , Pyrimidines , Treatment OutcomeABSTRACT
Purpose: CPI-613, a lipoate analogue that inhibits pyruvate dehydrogenase (PDH) and α-ketogluterate dehydrogenase (KGDH), has activity in patients with myeloid malignancies. This study explored the role of mitochondrial metabolism in chemotherapy response and determined the MTD, efficacy, and safety of CPI-613 combined with high-dose cytarabine and mitoxantrone in patients with relapsed or refractory acute myeloid leukemia.Experimental Design: The role of mitochondrial response to chemotherapy was assessed in cell lines and animal models. A phase I study of CPI-613 plus cytarabine and mitoxantrone was conducted in patients with relapsed or refractory AML.Results: Exposure to chemotherapy induced mitochondrial oxygen consumption that depended on PDH. CPI-613 sensitized AML cells to chemotherapy indicating that mitochondrial metabolism is a source of resistance. Loss of p53 did not alter response to CPI-613. The phase I study enrolled 67 patients and 62 were evaluable for response. The overall response rate was 50% (26CR+5CRi/62). Median survival was 6.7 months. In patients over 60 years old, the CR/CRi rate was 47% (15/32) with a median survival of 6.9 months. The response rate for patients with poor-risk cytogenetics also was encouraging with 46% (11/24 patients) achieving a CR or CRi. RNA sequencing analysis of a subset of baseline bone marrow samples revealed a gene expression signature consistent with the presence of B cells in the pretreatment marrow of responders.Conclusions: The addition of CPI-613 to chemotherapy is a promising approach in older patients and those with poor-risk cytogenetics. Clin Cancer Res; 24(9); 2060-73. ©2018 AACR.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Leukemia, Myeloid, Acute/drug therapy , Leukemia, Myeloid, Acute/pathology , Adult , Aged , Animals , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Biomarkers , Biopsy , Bone Marrow/pathology , Caprylates/administration & dosage , Cell Line , Cell Respiration/drug effects , Cytarabine/administration & dosage , Drug Resistance, Neoplasm , Female , Humans , Leukemia, Myeloid, Acute/metabolism , Leukemia, Myeloid, Acute/mortality , Male , Mice , Middle Aged , Mitochondria/drug effects , Mitochondria/genetics , Mitochondria/metabolism , Mitoxantrone/administration & dosage , Neoplasm Grading , Neoplasm Staging , Oxygen Consumption/drug effects , Recurrence , Retreatment , Sulfides/administration & dosage , Treatment Outcome , Young AdultABSTRACT
Patients with Acute Myeloid Leukemia (AML) have compromised marrow function and chemotherapy causes further suppression. As a result complications are frequent, and patients may require admission to the intensive care unit (ICU). How codes status changes when these events occur and how those changes influence outcome are largely unknown. Outcomes for adult patients with AML, undergoing induction chemotherapy, and transferred to the ICU between January 2000 and December 2013 were analyzed. 94 patients were included. Median survival was 1.3 months. At 3 and 6 months overall survival (OS) was 27% and 18% respectively. Respiratory failure was the most common reason for transfer to ICU (88%), with 63% requiring mechanical ventilation at transfer. Other reasons included: cardiac arrest (18%), septic shock (17%), hypotension (9%), and acute renal failure (9%). The most frequent interventions were mechanical ventilation in 85%, vasopressors in 62%, and hemodialysis in 30%. Following transfer 55 patients (58%) had a change in code status. Overall, 46 patients (49%) changed from Full Code (FC) to Comfort Care (CC), 7 (7%) from FC to Do Not Resuscitate (DNR), and 2 (2%) from DNR to CC. For the entire cohort, ICU mortality (IM) was 61% and hospital mortality (HM) was 71%. For FC or DNR patients, IM was 30% and HM was 41%. For CC patients, IM was 90% and HM was 100%. Overall, 27 patients (29%) survived to discharge. Of those discharged, 22 (81%) were alive at 3 months and 17 (63%) were alive at 6 months. In conclusion, patients that required ICU admission during induction chemotherapy have a poor prognosis. Code status changed during the ICU stay for the majority of patients and always to a less aggressive status.
Subject(s)
Intensive Care Units/statistics & numerical data , Leukemia, Myeloid, Acute/mortality , Resuscitation Orders , Adult , Aged , Aged, 80 and over , Female , Humans , Induction Chemotherapy/methods , Kaplan-Meier Estimate , Leukemia, Myeloid, Acute/drug therapy , Male , Middle Aged , Patient Transfer/statistics & numerical data , Retrospective StudiesABSTRACT
OBJECTIVES: To measure short-term changes in physical and cognitive function and emotional well-being of older adults receiving intensive chemotherapy for acute myeloid leukemia (AML). DESIGN: Prospective observational study. SETTING: Single academic institution. PARTICIPANTS: Individuals aged 60 and older with newly diagnosed AML who received induction chemotherapy (N = 49, mean age 70 ± 6.2, 56% male). MEASUREMENTS: Geriatric assessment (GA) was performed during inpatient examination for AML and within 8 weeks after hospital discharge after induction chemotherapy. Measures were the Pepper Assessment Tool for Disability (activity of daily living, instrumental activity of daily living (IADL), mobility questions), Short Physical Performance Battery (SPPB), grip strength, Modified Mini-Mental State examination, Center for Epidemiologic Studies Depression Scale, and the Distress Thermometer. Changes in GA measures were assessed using paired t-tests. Analysis of variance models were used to evaluate relationships between GA variables and change in function over time. RESULTS: After chemotherapy, IADL dependence worsened (mean 1.4 baseline vs 2.1 follow-up, P < .001), as did mean SPPB scores (7.5 vs 5.9, P = .02 for total). Grip strength also declined (38.9 ± 7.7 vs 34.2 ± 10.3 kg, P < .001 for men; 24.5 ± 4.8 vs 21.8 ± 4.7 kg, P = .007 for women). No significant changes in cognitive function (mean 84.7 vs 85.1, P = .72) or depressive symptoms (14.0 vs. 11.3, P = .11) were detected, but symptoms of distress declined (5.0 vs 3.2, P < .001). Participants with depressive symptoms at baseline and follow-up had greater declines in SPPB scores those without at both time points. CONCLUSIONS: Short-term survivors of intensive chemotherapy for AML had clinically meaningful declines in physical function. These data support the importance of interventions to maintain physical function during and after chemotherapy. Depressive symptoms before and during chemotherapy may be linked to potentially modifiable physical function declines.
Subject(s)
Activities of Daily Living/psychology , Cognition/physiology , Depression , Induction Chemotherapy , Leukemia, Myeloid, Acute , Aged , Depression/diagnosis , Depression/etiology , Depression/prevention & control , Female , Geriatric Assessment/methods , Humans , Induction Chemotherapy/adverse effects , Induction Chemotherapy/methods , Induction Chemotherapy/psychology , Leukemia, Myeloid, Acute/diagnosis , Leukemia, Myeloid, Acute/drug therapy , Leukemia, Myeloid, Acute/physiopathology , Leukemia, Myeloid, Acute/psychology , Male , Mental Health , Middle Aged , Mobility Limitation , Patient Discharge , Physical Examination/methods , Prospective Studies , SurvivorsABSTRACT
Polycythemia vera (PV) is a chronic myeloproliferative neoplasm that is associated with a substantial symptom burden, thrombohemorrhagic complications, and impaired survival. A decade after the seminal discovery of an activating mutation in the tyrosine kinase JAK2 in nearly all patients with PV, new treatment options are finally beginning to emerge, necessitating a critical reappraisal of the underlying pathogenesis and therapeutic modalities available for PV. Herein, we comprehensively review clinical aspects of PV including diagnostic considerations, natural history, and risk factors for thrombosis. We summarize recent studies delineating the genetic basis of PV, including their implications for evolution to myelofibrosis and secondary acute myeloid leukemia. We assess the quality of evidence to support the use of currently available therapies, including aspirin, phlebotomy, hydroxyurea, and interferon. We analyze recent studies evaluating the safety and efficacy of JAK inhibitors, such as ruxolitinib, and evaluate their role in the context of other available therapies for PV. This review provides a framework for practicing hematologists and oncologists to make rational treatment decisions for patients with PV.
Subject(s)
Interferon-beta/therapeutic use , Janus Kinase 2/genetics , Point Mutation , Polycythemia Vera/genetics , Polycythemia Vera/therapy , Polyethylene Glycols/therapeutic use , Aspirin/therapeutic use , Clinical Trials, Phase II as Topic , Disease Progression , Female , Humans , Hydroxyurea/therapeutic use , Incidence , Male , Phlebotomy/methods , Polycythemia Vera/epidemiology , Prognosis , Randomized Controlled Trials as Topic , Risk Assessment , Treatment OutcomeABSTRACT
Acute myeloid leukemia (AML) is an aggressive malignancy that affects older patients. The role of salvage therapy in the elderly is controversial and there is little data on efficacy. Outcomes for 94 relapsed or refractory AML patients who received salvage HAMA therapy were analyzed. Of the 94 patients 66 were ≥60, including 26 patients ≥70, and 28 were <60 years old. Early mortality (30-day) was 14% (4%<60, 18%≥60 years old). Overall, 27% of patients died during hospitalization or were discharged to hospice (11%<60, 33%≥60 years old). CR/CRi was achieved in 41% of patients (61%<60, 33%≥60 years old). Median survival was 6.1 months (15.7<60, 5.2≥60). Patients ≥60 who achieved a CR/CRi had a median survival of 11.7 months. At 12 months 56% of patients <60 were alive versus 24% of patients ≥60. At 24 months these numbers fell to 40% and 2% respectively. In those <60 years old, 50% went on to allogeneic hematopoietic stem cell transplant (HSCT) whereas 14% of patients in the ≥60 cohort did so. In conclusion, HAMA salvage therapy results in a 33% response rate in patients ≥60 years old with acceptable toxicity.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols , Hematopoietic Stem Cell Transplantation , Leukemia, Myeloid, Acute/drug therapy , Salvage Therapy/methods , Adult , Aged , Aged, 80 and over , Asparaginase/administration & dosage , Cytarabine/administration & dosage , Drug Administration Schedule , Female , Humans , Karyotype , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/mortality , Leukemia, Myeloid, Acute/pathology , Male , Middle Aged , Mitoxantrone/administration & dosage , Recurrence , Remission Induction , Retrospective Studies , Survival Analysis , Transplantation, Homologous , Treatment OutcomeABSTRACT
As the second most prevalent hematologic malignancy, multiple myeloma (MM) remains incurable and relapses due to intrinsic or acquired drug resistance. Therefore, new therapeutic strategies that target molecular mechanisms responsible for drug resistance are attractive. Interactions of tumor cells with their surrounding microenvironment impact tumor initiation, progression and metastasis, as well as patient prognosis. This cross-talk is bidirectional. Tumor cells can also attract or activate tumor-associated stromal cells by releasing cytokines to facilitate their growth, invasion and metastasis. The effect of myeloma cells on bone marrow stromal cells (BMSCs) has not been well studied. In our study, we found that higher stiffness of BMSCs was not a unique characteristic of BMSCs from MM patients (M-BMSCs). BMSCs from MGUS (monoclonal gammopathy of undetermined significance) patients were also stiffer than the BMSCs from healthy volunteers (N-BMSCs). The stiffness of M-BMSCs was enhanced when cocultured with myeloma cells. In contrast, no changes were seen in myeloma cell-primed MGUS- and N-BMSCs. Interestingly, our data indicated that CD138⻠myeloma cells, but not CD138⺠cells, regulated M-BMSC stiffness. SDF-1 was highly expressed in the CD138⻠myeloma subpopulation compared with that in CD138⺠cells. Inhibition of SDF-1 using AMD3100 or knocking-down CXCR4 in M-BMSCs blocked CD138⻠myeloma cells-induced increase in M-BMSC stiffness, suggesting a crucial role of SDF-1/CXCR4. AKT inhibition attenuated SDF-1-induced increases in M-BMSC stiffness. These findings demonstrate, for the first time, CD138⻠myeloma cell-directed cross-talk with BMSCs and reveal that CD138⻠myeloma cells regulate M-BMSC stiffness through SDF-1/CXCR4/AKT signaling.
Subject(s)
Chemokine CXCL12/metabolism , Mesenchymal Stem Cells/pathology , Multiple Myeloma/metabolism , Multiple Myeloma/pathology , Proto-Oncogene Proteins c-akt/metabolism , Receptors, CXCR4/metabolism , Syndecan-1/metabolism , Biomechanical Phenomena , Enzyme Activation/drug effects , Focal Adhesion Protein-Tyrosine Kinases/metabolism , Humans , Mesenchymal Stem Cells/drug effects , Mesenchymal Stem Cells/metabolism , Monoclonal Gammopathy of Undetermined Significance/metabolism , Monoclonal Gammopathy of Undetermined Significance/pathology , Myosin Light Chains/metabolism , Phosphorylation/drug effects , Recombinant Proteins/pharmacology , Signal Transduction/drug effects , rhoA GTP-Binding Protein/metabolismABSTRACT
The hypomethylating agents (HAs), azacitidine and decitabine, have emerged as an alternative to initial and salvage therapy in patients with acute myeloid leukemia (AML). Little is known about how AML responds to hypomethylating agents after standard therapy, and the activity of these agents in a real-world setting is not well studied. We retrospectively examined data for 75 consecutive AML patients at Wake Forest from 2002 to 2011 treated with HAs either as first-line (n = 34), salvage (n = 28), or consolidation (n = 13) therapy. We collected data on age, gender, race, Charlson comorbidity index (CCI), cytogenetics, type of treatment, complete remission (CR), complete remission with incomplete count recovery (CRi), and survival. Statistical analysis was performed using Kaplan-Meier estimates and Cox proportional hazards models. Frontline response rate (CR + CRi) was 26.5 %, and median overall survival (OS) was 3.4 months (95 % CI 1.3-7.4), with 18 % alive at 1 year. In the salvage cohort, the response rate was significantly lower compared to frontline (3.6 versus 26.5 %, p = 0.017). Despite the reduced response, OS from time of HA treatment was longer than frontline at 8.2 months (CI 4.8-10.3). In the consolidation cohort, OS was 13.8 months (CI 8.0-21.6) with one patient in remission more than 30 months from diagnosis. These data suggest that prior cytotoxic therapy decreases marrow response rates to HAs but not survival. Furthermore, use of hypomethylating agents for consolidation resulted in a median overall survival over 1 year in a cohort of older patients. This suggests that hypomethylating agents have activity in all phases of AML treatment.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Azacitidine/analogs & derivatives , Azacitidine/pharmacology , DNA Methylation/drug effects , Leukemia, Myeloid, Acute/drug therapy , Age Factors , Aged , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Azacitidine/administration & dosage , Comorbidity , Consolidation Chemotherapy , DNA (Cytosine-5-)-Methyltransferases/antagonists & inhibitors , DNA Damage , DNA, Neoplasm/drug effects , Decitabine , Drug Evaluation , Female , Humans , Kaplan-Meier Estimate , Leukemia, Myeloid, Acute/metabolism , Male , Middle Aged , Neoplasm Proteins/antagonists & inhibitors , Proportional Hazards Models , Remission Induction , Retrospective Studies , Salvage Therapy , Survival RateABSTRACT
Ag-specific memory T cell responses elicited by infections or vaccinations are inextricably linked to long-lasting protective immunity. Studies of protective immunity among residents of malaria endemic areas indicate that memory responses to Plasmodium Ags are not adequately developed or maintained, as people who survive episodes of childhood malaria are still vulnerable to either persistent or intermittent malaria infections. In contrast, multiple exposures to radiation-attenuated Plasmodium berghei sporozoites (Pb γ-spz) induce long-lasting protective immunity to experimental sporozoite challenge. We previously demonstrated that sterile protection induced by Pb γ-spz is MHC class I-dependent and CD8 T cells are the key effectors. IFN-γ(+) CD8 T cells that arise in Pb γ-spz-immunized B6 mice are found predominantly in the liver and are sensitive to levels of liver-stage Ag depot and they express CD44(hi)CD62L(lo) markers indicative of effector/effector memory phenotype. The developmentally related central memory CD8 T (TCM) cells express elevated levels of CD122 (IL-15Rß), which suggests that CD8 TCM cells depend on IL-15 for maintenance. Using IL-15-deficient mice, we demonstrate in this study that although protective immunity is inducible in these mice, protection is short-lived, mainly owing to the inability of CD8 TCM cells to survive in the IL-15-deficient milieu. We present a hypothesis consistent with a model whereby intrahepatic CD8 TCM cells, being maintained by IL-15-mediated survival and basal proliferation, are conscripted into the CD8 effector/effector memory T cell pool during subsequent infections.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , Interleukin-15/immunology , Malaria/immunology , Plasmodium berghei/immunology , Animals , Female , Immunization , Immunologic Memory , Interferon-gamma/immunology , Interleukin-15/deficiency , Interleukin-15/genetics , Liver/immunology , Liver/parasitology , Malaria Vaccines/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , Plasmodium berghei/radiation effects , Sporozoites/immunologyABSTRACT
Presently, blood transfusion products (TPs) are composed of terminally differentiated cells with a finite life span. We have developed an ex vivo-generated TP composed of erythroid progenitor cells (EPCs) and precursors cells. Several histone deacetylase inhibitors (HDACIs) were used in vitro to promote the preferential differentiation of cord blood (CB) CD34(+) cells to EPCs. A combination of cytokines and valproic acid (VPA): (1) promoted the greatest degree of EPC expansion, (2) led to the generation of EPCs which were capable of differentiating into the various stages of erythroid development, (3) led to epigenetic modifications (increased H3 acetylation) of promoters for erythroid-specific genes, which resulted in the acquisition of a gene expression pattern characteristic of primitive erythroid cells, and (4) promoted the generation of a TP that when infused into NOD/SCID mice produced mature RBCs containing both human adult and fetal globins as well Rh blood group Ag which persisted for 3 weeks and the retention of human EPCs and erythroid precursor cells within the BM of recipient mice. This ex vivo-generated EPC-TP likely represents a paradigm shift in transfusion medicine because of its potential to continue to generate additional RBCs after its infusion.
Subject(s)
Chromatin/drug effects , Cord Blood Stem Cell Transplantation/methods , Erythroid Cells/cytology , Hematopoietic Stem Cells/drug effects , Histone Deacetylase Inhibitors/pharmacology , Hydroxamic Acids/pharmacology , Acetylation/drug effects , Animals , Antigens, CD34/metabolism , Cell Differentiation/drug effects , Cells, Cultured , Fetal Blood/cytology , Gene Expression/drug effects , Gene Expression/physiology , Hematopoietic Stem Cells/cytology , Hematopoietic Stem Cells/metabolism , Histones/metabolism , Humans , Mice , Mice, Inbred NOD , Mice, SCID , Phenotype , Promoter Regions, Genetic/physiology , Valproic Acid/pharmacologyABSTRACT
Polycythemia vera (PV) treatment with interferon α (IFNα) is frequently limited by dose-related toxicity. PV CD34(+) cells are characterized by overexpression of Bcl-xL, which can be antagonized by ABT-737 leading to apoptosis. We explored the effects of ABT-737 and IFNα on PV hematopoiesis. Both IFNα and ABT-737 alone or in combination had a modest effect on normal hematopoiesis but each individually were able to markedly induce PV CD34(+) cell apoptosis and suppress hematopoietic colony formation. The inhibitory activities of these agents in combination were greater against PV hematopoiesis than either agent alone. The exposure of PV CD34(+) cells to low doses of IFNα and ABT-737 in combination resulted in the reduction of the proportion of JAK2V617F(+) colonies similar to that observed with higher doses of IFNα. These data provide the rationale for combination therapy with low doses of IFNα and a BH3 mimetic for patients with PV.
Subject(s)
Amino Acid Substitution/genetics , Biphenyl Compounds/pharmacology , Hematopoietic Stem Cells/drug effects , Interferon-alpha/pharmacology , Janus Kinase 2/genetics , Nitrophenols/pharmacology , Polycythemia Vera/enzymology , Polyethylene Glycols/pharmacology , Sulfonamides/pharmacology , bcl-X Protein/antagonists & inhibitors , Antigens, CD34/metabolism , Biphenyl Compounds/therapeutic use , Bone Marrow Cells/drug effects , Bone Marrow Cells/pathology , Colony-Forming Units Assay , Drug Synergism , Fetal Blood/cytology , Hematopoietic Stem Cells/enzymology , Humans , Interferon alpha-2 , Janus Kinase 2/metabolism , Nitrophenols/therapeutic use , Piperazines/pharmacology , Piperazines/therapeutic use , Polycythemia Vera/drug therapy , Polycythemia Vera/pathology , Recombinant Proteins , Sulfonamides/therapeutic use , bcl-X Protein/metabolismABSTRACT
OBJECTIVE: Interferon-alpha (IFNalpha) therapy leads to hematological remissions and a reduction of the JAK2V617F allele burden in patients with polycythemia vera (PV). In this study, the cellular target by which IFNalpha affects hematopoiesis in PV patients was evaluated. MATERIALS AND METHODS: CD34(+) cells were isolated from normal bone marrow and the peripheral blood of patients with PV and were treated in vitro with each of the three commercially available forms of IFNalpha: IFNalpha 2b, pegylated IFNalpha 2a (Peg-IFNalpha 2a), and pegylated IFNalpha 2b (Peg-IFNalpha 2b). RESULTS: Each form of IFNalpha was equally potent in suppressing hematopoietic colony formation by normal CD34(+) cells, but Peg-IFNalpha 2a and IFNalpha 2b were more effective than Peg-IFNalpha 2b in inhibiting burst-forming unit erythroid-derived colony formation by PV CD34(+) cells. In addition, exposure of PV CD34(+) cells to equal doses of Peg-IFNalpha 2a and IFNalpha 2b resulted in a 38% to 40% reduction in the proportion of JAK2V617F-positive hematopoietic progenitor cells (HPC), while equivalent doses of Peg-IFNalpha 2b did not reduce the number of malignant HPC. Further studies explored the mechanism by which IFNalpha induced PV HPC growth inhibition. Treatment of Peg-IFNalpha 2a increased the rate of apoptosis of PV CD34(+) cells and the phosphorylation/activation of p38 mitogen-activated protein kinase in PV CD34(+) cells, while the p38-specific inhibitor SB203580 reversed the growth inhibition and apoptosis induced by Peg-IFNalpha 2a. CONCLUSION: These data suggest that low doses of IFNalpha selectively and directly suppress PV JAK2V617F HPC and that these agents act through the p38 mitogen-activated protein kinase pathway.