[Show abstract][Hide abstract] ABSTRACT: Abstract The optimal tyrosine kinase inhibitor for any individual patient with chronic myeloid leukemia (CML) is not predictable. Pharmacogenetic parameters and trough levels of imatinib (IM) have each been independently correlated with response. We therefore studied hOCT1 and MDR1 single nucleotide polymorphisms (SNPs) and correlated these with IM levels and MMR (3 log reduction) in 84 CML patients, the first such study performed in Caucasians. We studied MDR1 G2677T and C3435T and for hOCT1, C480G and A1222G. IM levels significantly varied with dose (< or >400mg/day) (p=0.038) and were significantly lower in 20 patients who lost MMR (p=0.042). Adjusting for dose, trough IM levels were not significantly correlated with SNPs. Patients with MDR1 3435 TT had significantly longer times to MMR compared to CC/CT genotypes (p=0.047). Genotypes did not predict treatment failure when controlling for IM levels. We conclude that IM levels, but not the SNPs studied here, determine IM failure.
[Show abstract][Hide abstract] ABSTRACT: PML-RARA and AML1-ETO are important oncogenic fusion proteins that play a central role in transformation to acute myeloid leukemia (AML). Whether these fusion proteins render the tumor cells with immune evasion properties is unknown. Here we show that both oncogenic proteins specifically downregulate the expression of CD48, a ligand of the natural killer (NK) cell activating receptor 2B4, thereby leading to decreased killing by NK cells. We demonstrate that this process is histone deacetylase (HDAC)-dependent, that it is mediated through the downregulation of CD48 mRNA and that treatment with HDAC inhibitors (HDACi) restores the expression of CD48. Furthermore, by using chromatin immuoprecepitation (ChIP) experiments we show that AML1-ETO directly interacts with CD48. Finally, we show that AML patients carrying these specific translocations have low expression of CD48.
[Show abstract][Hide abstract] ABSTRACT: Molecular and genetic evidence suggests that DNA repair pathways may contribute to lymphoma susceptibility. Several studies have examined the association of DNA repair genes with lymphoma risk, but the findings from these reports have been inconsistent. Here we provide the results of a focused analysis of genetic variation in DNA repair genes and their association with the risk of non-Hodgkin's lymphoma (NHL). With a population of 1,297 NHL cases and 1,946 controls, we have performed a two-stage case/control association analysis of 446 single nucleotide polymorphisms (SNPs) tagging the genetic variation in 81 DNA repair genes. We found the most significant association with NHL risk in the ATM locus for rs227060 (OR = 1.27, 95% CI: 1.13-1.43, p = 6.77×10-5), which remained significant after adjustment for multiple testing. In a subtype-specific analysis, associations were also observed for the ATM locus among both diffuse large B-cell lymphomas (DLBCL) and small lymphocytic lymphomas (SLL), however there was no association observed among follicular lymphomas (FL). In addition, our study provides suggestive evidence of an interaction between SNPs in MRE11A and NBS1 associated with NHL risk (OR = 0.51, 95% CI: 0.34-0.77, p = 0.0002). Finally, an imputation analysis using the 1,000 Genomes Project data combined with a functional prediction analysis revealed the presence of biologically relevant variants that correlate with the observed association signals. While the findings generated here warrant independent validation, the results of our large study suggest that ATM may be a novel locus associated with the risk of multiple subtypes of NHL.
PLoS ONE 01/2014; 9(7):e101685. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Livin is a member of the Inhibitor of Apoptosis (IAP) protein family that inhibits apoptosis triggered by a variety of stimuli. We previously demonstrated that while Livin inhibits caspase activity, caspases can cleave Livin to produce a truncated protein, tLivin and that this newly formed tLivin paradoxically induces cell death. However to date, the mechanism of tLivin-induced cell death is not fully understood. In this study, we set out to characterize the form of cell death mediated by tLivin. Here we demonstrate that, unlike most death-promoting proteins, tLivin is a flexible inducer of cell death capable of promoting necrosis or apoptosis in different cell lines. The unusual flexibility of tLivin is displayed by its ability to activate an alternative form of cell death when apoptosis is inhibited. Thus, tLivin can promote more than one form of cell death in the same cell type. Interestingly, in cells where tLivin induces necrosis, deletion of the caspase binding BIR domain results in tLivin-induced apoptosis, suggesting the BIR domain can potentially hamper the ability of tLivin to induce apoptosis. We further elucidate that tLivin activates the JNK pathway and both tLivin-induced apoptosis and necrosis are partially mediated by JNK activity. Acquired resistance to apoptosis, common in many tumors, impinges on the efficiency of conventional anti-cancer agents that function primarily by inducing apoptosis. The ability of tLivin to induce death of apoptosis-compromised cells makes it an attractive candidate for targeted cancer therapy.
PLoS ONE 01/2014; 9(6):e101075. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Livin is a member of the inhibitor of apoptosis proteins (IAP) family of intracellular antiapoptotic proteins that act by binding and inhibiting caspases. Upon strong apoptotic stimuli, it is then specifically cleaved by caspases to produce a truncated protein (tLivin) with a paradoxical proapoptotic activity. Intriguingly, we have detected robust protein levels of Livin in normal mature bone marrow megakaryocyte (MK) and platelets. To evaluate the potential role of Livin in thrombopoiesis, we used the human BCR-ABL+ cell line, LAMA-84, and cord blood CD34+ cells to induce differentiation toward MKs. Upon differentiation, induced by phorbol myristate acetate and concurrent with increase in Livin protein expression, LAMA-84 cells formed functional platelet-like particles. Livin overexpression in CD34+ progenitor cells induced higher endoreplication in the MKs generated. Furthermore, overexpression of Livin increased the ability of both primary MKs and differentiated LAMA-84 cells to produce functional platelets. In the differentiated LAMA-84 cells, we observed accumulation of proapoptotic tLivin concomitant with increased caspase-3 activity. Downregulation of Livin with small interfering RNA in both leukemic and primary MK cells decreased their ability to produce functional platelets. We suggest that Livin has a role in thrombopoiesis by regulating the apoptotic and antiapoptotic balance in MK endoreplication and platelet production.
Cell Death & Disease 11/2013; 4:e937. · 6.04 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Loss of nerve growth factor-mediated neuronal survival has
recently been proposed as a candidate mechanism underlying
bortezomib-induced peripheral neuropathy (BIPN) (Broyl
et al, 2010). However the literature does not reveal any data
from patients that can support this hypothesis. Brain-derived
neurotrophic factor (BDNF) is a neuronal growth factor that
is crucial for neuronal survival and repair (Hofer & Barde,
1988). We report on alterations in BDNF peripheral blood
levels and the development of BIPN in patients with multiple
British Journal of Haematology 10/2013; · 4.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Immune hemolytic anemia (IHA) may complicate the course of chronic lymphocytic leukemia (CLL), especially in patients with advanced disease, and as a complication of treatment with chlorambucil or fludarabine. Bendamustine, a novel agent with both alkylating and purine-analog properties, was approved in the USA for use in CLL in 2008. Since then, clinical data on its adverse events are accumulating. IHA related to bendamustine was seldom described and is thus reported and reviewed.
We assessed five cases of CLL patients complicated by IHA, out of 31 treated with bendamustine for a relapse of their disease. Also reviewed are previous case reports in the literature.
Bendamustine-related IHA is more common than suspected (16 %). No such cases were found in non-CLL patients. Personal history of fludarabine-triggered AIHA may be a risk factor for this complication (recorded in 4/5 patients, 80 %). The mechanism is thought to be related to the loss of T cell regulatory control as described for other agents. Physicians using bendamustine for the treatment for CLL should be aware of this complication.
Cancer Chemotherapy and Pharmacology 08/2013; · 2.80 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The genetics of lymphoma susceptibility reflect the marked heterogeneity of diseases that comprise this broad phenotype. However, multiple subtypes of lymphoma are observed in some families, suggesting shared pathways of genetic predisposition to these pathologically distinct entities. Using a two-stage GWAS, we tested 530,583 SNPs in 944 cases of lymphoma, including 282 familial cases, and 4,044 public shared controls, followed by genotyping of 50 SNPs in 1,245 cases and 2,596 controls. A novel region on 11q12.1 showed association with combined lymphoma (LYM) subtypes. SNPs in this region included rs12289961 near LPXN, (P(LYM) = 3.89×10(-8), OR = 1.29) and rs948562 (P(LYM) = 5.85×10(-7), OR = 1.29). A SNP in a novel non-HLA region on 6p23 (rs707824, P(NHL) = 5.72×10(-7)) was suggestive of an association conferring susceptibility to lymphoma. Four SNPs, all in a previously reported HLA region, 6p21.32, showed genome-wide significant associations with follicular lymphoma. The most significant association with follicular lymphoma was for rs4530903 (P(FL) = 2.69×10(-12), OR = 1.93). Three novel SNPs near the HLA locus, rs9268853, rs2647046, and rs2621416, demonstrated additional variation contributing toward genetic susceptibility to FL associated with this region. Genes implicated by GWAS were also found to be cis-eQTLs in lymphoblastoid cell lines; candidate genes in these regions have been implicated in hematopoiesis and immune function. These results, showing novel susceptibility regions and allelic heterogeneity, point to the existence of pathways of susceptibility to both shared as well as specific subtypes of lymphoid malignancy.
[Show abstract][Hide abstract] ABSTRACT: Advanced melanoma cells, characterized by resistance to chemotherapy, have been shown to be highly sensitive to oncolysis by Newcastle disease virus (NDV). In the present study, we investigated the capacity of NDV to specifically infect and spread into solid tissues of human melanoma and lung carcinoma, in vivo and ex vivo. For this purpose a new model of SCID-beige mice implanted with human melanoma was developed. Surprisingly, the replication competent NDV-MTH and the attenuated, single-cycle replication NDV-HUJ strains, demonstrated a similar oncolytic activity in the melanoma-implanted mice. Further, ex vivo analysis, using organ cultures derived from the melanoma tissues indicated a limited spread of the two NDV strains in the tissue. Extracellular matrix (ECM) molecules, notably heparin sulfate and collagen, were found to limit viral spread in the tissue. This observation was validated with yet another solid tumour of human lung carcinoma. Taken together, the results indicate that the ECM acts as a barrier to virus spread within solid tumour tissues and that this restriction must be overcome to achieve effective oncolysis with NDV.
Journal of General Virology 05/2012; 93(Pt 8):1664-72. · 3.13 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The inhibitor of apoptosis protein (IAP) livin is frequently overexpressed in melanoma. Livin binds caspases and thereby inhibits apoptosis. We found that caspases cleave livin to produce a truncated form with a paradoxical proapoptotic activity.
We assessed the correlation of livin expression with survival among 114 melanoma patients treated with an autologous melanoma vaccine. In 52 patients, resection resulted in no evidence of disease (NED) and 62 remained with active disease (WAD). Protein levels were assessed using Western blot.
We found livin protein expression in 44/114 samples (38.4%). Median overall survival was 1.4 years in NED patients with high levels of livin protein, 8.4 years in those with low-intermediate levels and not reached in patients who did not express livin (p = 0.025). The corresponding overall survival was 2.3 years among WAD patients with high levels of livin protein, 11.3 years in those with low-intermediate levels and, paradoxically, only 4.0 years in patients who did not express livin (p = 0.012).
Livin protein expression may play a role in the progression of melanoma and correlates with survival. A high level of the protein is associated with a poor prognosis. However, in WAD patients low to intermediate level of livin, rather than absence of the protein, is associated with a favorable prognosis. This is probably due to the paradoxical proapoptotic activity of this important regulator of apoptosis.
[Show abstract][Hide abstract] ABSTRACT: Treatment of hairy cell leukemia (HCL) with cladribine induces durable remissions. Common toxicities are myelosuppression and immunosuppression with low counts of CD4 + T cells. Skin rash (SR) is seldom described. We collected clinical and laboratory data of 35 patients with HCL treated in Hadassah between January 1999 and February 2010, in order to evaluate the frequency and characteristics of SR after treatment with cladribine. We found a high frequency of SR in our group of patients (18/35 patients, 51%), mostly related to febrile neutropenia and concomitant treatment with penicillins/trimethoprim-sulfamethoxazole (TMP-SMZ). The lymphocyte count was low in all patients with SR. We conclude that patients with HCL treated with cladribine have an increased rate of drug hypersensitivity, possibly due to T-cell imbalance induced by cladribine. Since TMP-SMZ and penicillins are related to SR in most cases and are important in the management of patients with HCL, a desensitization protocol should be considered. Rechallenge may be safe after immune reconstitution.
[Show abstract][Hide abstract] ABSTRACT: The JAK2 V617F mutation is responsible for the constitutive activation of the erythropoietin receptor signaling pathway in most cases of polycythemia vera (PV). The mutation has also been described in healthy people. As smoking may result in secondary polycythemia, the goal of this trial was to examine the effect of smoking on the prevalence of the JAK2 mutation and its correlation to erythrocytosis. The study was case-control. Hospitalized smokers (n = 81) and nonsmokers (n = 61) were recruited. Serum was drawn for complete blood count, erythropoietin, ferritin and venous blood gases. JAK2 mutation was analyzed by highly sensitive allele-specific Quantitative Real Time PCR. The JAK2 mutation was found in 29/81 (35.8%) of smokers in comparison to only 9/61 (14.8%) of the control group (P = 0.007). The frequency of the mutation among smokers who were positive for the JAK2 mutation had a mean of 6.78 × 10(-4) ± 1.08 × 10(-3) vs. 1.51 × 10(-4) ± 2.04 × 10(-4) among nonsmokers (P = 0.027). Both frequencies are much lower than those found in PV. There was a medium correlation between older age and mutation frequency in nonsmokers (r= 0.67, P = 0.043). Hematocrit was higher in smokers (47.8 ± 6 vs. 41.7 ± 4.7, P < 0.0001), but no correlation was found to JAK2 mutation. In a cohort of hospitalized smokers and nonsmokers, JAK2 mutation was more prevalent and found in higher frequencies among smokers than nonsmokers. We suggest that accelerated erythropoiesis renders the cells susceptible to JAK2 mutation.
American Journal of Hematology 09/2011; 87(1):5-8. · 4.00 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this retrospective study, we aim to analyze the characteristics, treatments, and overall survival of all patients presenting with isolated myeloid sarcoma (MS) or MS with concomitant acute myeloid leukemia (AML) compared with all patients with AML, treated during the same period. We identified patients with AML with or without MS at diagnosis, presenting to our medical center between the years 1990 and 2005. There was no statistically significant difference between the groups regarding gender, age, cytogenetic risk groups, rate of complete remission, number of cycles of chemotherapy needed to achieve complete remission, and rate of first relapse. The time to death in the MS group was not significantly different (p = 0.60) from the AML group, and radiotherapy did not affect the median time to death. Transplantation prolonged survival in both groups (p = 0.018 and p < 0.0001, respectively). Patients with MS at diagnosis might benefit from upfront aggressive treatment with hematopoietic stem cell transplantation.
[Show abstract][Hide abstract] ABSTRACT: We present a case of a 52-year-old male who was evaluated due to anorexia, persistent diarrhea, weight loss, and liver enzyme elevations, with no hematologic laboratory abnormalities. Imaging modalities revealed several tissue lesions involving the pancreas, the right kidney, and an axillary lymph node. Diagnosis of Castleman disease was reached only due to the tissue obtained from the lymph node. Chemotherapy and immunosuppression led to a short remission. The patient underwent autologous stem cell transplantation, and has since been in remission. This case demonstrates the cryptogenic and chameleon-like nature of Castleman disease. Challenges in treating Castleman disease patients reflect current limitations and the need for a greater understanding of disease pathogenesis.
International journal of hematology 03/2011; 93(5):677-80. · 1.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Neurolymphomatosis (NL) is a rare clinical entity. The International Primary CNS Lymphoma Collaborative Group retrospectively analyzed 50 patients assembled from 12 centers in 5 countries over a 16-year period. NL was related to non-Hodgkin lymphoma in 90% and to acute leukemia in 10%. It occurred as the initial manifestation of malignancy in 26% of cases. The affected neural structures included peripheral nerves (60%), spinal nerve roots (48%), cranial nerves (46%), and plexus (40%) with multiple site involvement in 58%. Imaging studies often suggested the diagnosis with 77% positive magnetic resonance imaging, and 84% (16 of 19) positive computed tomography-positron emission tomography studies. Cerebrospinal fluid cytology was positive in 40%, and nerve biopsy confirmed the diagnosis in 23 of 26 (88%). Treatment in 47 patients included systemic chemotherapy (70%), intra-cerebrospinal fluid chemotherapy (49%), and radiotherapy (34%). Response to treatment was observed in 46%. The median overall survival was 10 months, with 12- and 36-month survival proportions of 46% and 24%, respectively. NL is a challenging diagnosis, but contemporary imaging techniques frequently detect the relevant neural invasion. An aggressive multimodality therapy can prevent neurologic deterioration and is associated with a prolonged survival in a subset of patients.
[Show abstract][Hide abstract] ABSTRACT: Patients with advanced melanoma usually do not benefit from conventional chemotherapy treatment. There is therefore a true need for a new kind of therapy for melanoma. One factor responsible for the poor prognosis of melanoma is the inhibitor of apoptosis protein (IAP) family member Livin. In this study, we applied a novel approach for the treatment of melanoma, using a unique strain of the oncolytic Newcastle disease virus (NDV-HUJ). We found that, unlike chemotherapeutic drugs, NDV-HUJ, a one-cycle replicating virus, overcomes the resistance to apoptosis of melanoma primary cultures that over express the Livin protein. In contrast, melanoma tumor cells that do not express Livin are relatively resistant to NDV-HUJ treatment. Furthermore, we show that NDV-HUJ-induced oncolysis is attributed to the dual function of Livin: although Livin inhibits apoptosis through the inhibition of caspases, under the robust apoptotic stimulation of NDV-HUJ, caspases can cleave Livin to create a truncated protein with a paradoxical proapoptotic activity. Thus, NDV-HUJ is a potent inducer of apoptosis that can overcome the antiapoptotic effect of Livin and allow cleavage of Livin into the proapoptotic tLivin protein. Moreover, the results indicate that the interferon system, which is functional in melanoma, is not involved in NDV-induced oncolysis. Taken together, our data offer the possibility of a new viral oncolytic treatment for chemoresistant melanoma.
Journal of Virology 10/2009; 84(1):639-46. · 5.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The inhibitor of apoptosis protein (IAP) family can inhibit apoptosis induced by a variety of stimuli. We and others previously described the IAP Livin (ML-IAP). We found that Livin is unique among the IAP members as, on a strong apoptotic stimulus, it is specifically cleaved by caspases to produce a truncated protein with paradoxical proapoptotic activity (tLivin). We also showed that Livin encodes two splicing variants, termed Livin alpha and beta, with diverse antiapoptotic effects in vitro. In this study, we compared the Livin isoforms in vivo. An animal model was established and the effects of Livin alpha and beta on the initiation and development of tumors were compared. In the animal model, Livin alpha promotes tumor initiation in comparison with control. Interestingly, the growth of tumors originating from cells expressing Livin beta was inhibited. In these tumors, Livin beta was cleaved and produced a high level of the proapoptotic tLivin beta that repressed tumor development. When we eliminated the proapoptotic effect of Livin beta by point mutations, the resulting antiapoptotic Livin beta mutants contributed to tumor progression. In terms of mechanism, we show that Livin beta tumors develop only in mice lacking natural killer (NK) cell activity. Thus, from the animal model, we can conclude that Livin plays a major role in tumorigenicity and that NK cells induce cleavage of Livin to its proapoptotic truncated protein that in turn inhibits tumor growth. Therefore, Livin and tLivin may serve as potential targets for cancer therapy.
Cancer Research 07/2009; 69(13):5475-80. · 9.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Major risk factors of oral squamous cell carcinoma (OSCC) are environmental and can lead to DNA mutagenesis. Mismatch repair (MMR) system functions to repair small DNA lesions, which can be targeted for promoter hypermethylation. We therefore wanted to test whether hypermethylation of MMR genes (hMLH1, hMSH2) could contribute to oral carcinogenesis by correlating the information to patient clinical data.
Genomic DNA was extracted from 28 OSCC and six normal oral epithelium samples. The methylation status of the two MMR genes was assessed using Methylation Specific PCR after DNA modification with sodium bisulfite. Serial sections of the same tissues were immunostained with antibodies against hMLH1 and hMSH2 protein.
Promoter hypermethylation was observed in 14/28 OSCC cases. Remarkably, 100% of patients with multiple oral malignancies showed hypermethylation in hMLH1 or hMSH2 compared with 31.5% of single tumor patients. In 10 cancer cases, expression of the hMLH1 and hMSH2 genes by immunostaining showed reduced or absence of expression of one of the genes, although some did not reflect the methylation status.
Hypermethylation of hMLH1 and hMSH2 might play a role in oral carcinogenesis and may be correlated with a tendency to develop multiple oral malignancies.
[Show abstract][Hide abstract] ABSTRACT: Natural killer (NK) cells are part of the innate immune system, capable of killing tumor and virally infected cells. NK cells induce apoptosis in the target cell by either granule- or receptor-mediated pathways. A set of inhibitory and activation ligands governs NK cell activation. As transformed cells often attempt to evade NK cell killing, up-regulation of a potential anti-apoptotic factor should provide a survival advantage. The inhibitor of apoptosis protein (IAP) family can inhibit apoptosis induced by a variety of stimuli. We have previously described a new IAP family member, termed Livin, which has two splice variants (alpha and beta) with differential anti-apoptotic activities. In this study, we explore the ability of Livin to inhibit NK cell-induced killing. We demonstrate that Livin beta moderately protects against NK cell killing whereas Livin alpha augments killing. We show that Livin beta inhibition in Jurkat cells is apparent upon concomitant activation of an inhibitory signal, suggesting that Livin augments an extrinsic inhibitory signal rather than functioning as an independent inhibitory mechanism. Finally, we demonstrate that detection of both Livin isoforms in melanoma cells correlates with a low killing rate. To date, this is the first evidence that directly demonstrates the ability of IAP to protect against NK cell-induced apoptosis.
European Journal of Immunology 01/2008; 37(12):3467-76. · 4.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Therapy-related myelodysplastic syndrome/acute myeloid leukemia (t-MDS/AML) is an increasingly recognized treatment complication in patients treated with radiotherapy or chemotherapy for previous hematologic malignancies or solid tumors. Distinct clinical entities have been described according to the primary treatment, corresponding to defined genetic lesions. Chromosome 7 and/or 5 losses or deletions are typical of alkylating agent-induced AML, while development of t-AML with balanced translocations involving chromosome bands 11q23 and 21q22 has been related to previous therapy with drugs targeting DNA-topoisomerase II. In addition, antimetabolites, and in particular the immunosuppressant azathioprine, have been shown to induce defective DNA-mismatch repair. This could promote survival of misrepaired cells giving rise to the leukemic clone. Individual predisposing factors, including polymorphisms in detoxification and DNA repair enzymes have been identified. Their combination may significantly increase the risk of t-MDS/AML. Among patients with hematologic malignancies, long-term survivors of Hodgkin's lymphoma are exposed to an increased risk of t-MDS/AML, particularly when receiving MOPP-based, and escalated BEACOPP regimens, and when alkylators are combined with radiotherapy. Patients with Hodgkin's and non-Hodgkin's lymphoma are at highest risk when total body irradiation followed by autologous stem cell transplantation is used as rescue or consolidation therapy. The addition of granulocyte-colony-stimulating factor and radiotherapy plays a significant role in t-AML following treatment of children with acute lymphoblastic leukemia. In non-hematologic malignancies, treatment for breast cancer and germ-cell tumors has been associated with a 1-5% lifetime risk of both lymphoid as well as myeloid leukemia. In all cases the risk of t-MDS/AML drops sharply by 10 years after treatment.