Insulin Substrate Receptor (IRS) proteins in normal and malignant hematopoiesis.

The insulin receptor substrate (IRS) proteins are a family of cytoplasmic proteins that integrate and coordinate the transmission of signals from the extracellular to the intracellular environment via transmembrane receptors, thus regulating cell growth, metabolism, survival and proliferation. The PI3K/AKT/mTOR and MAPK signaling pathways are the best-characterized downstream signaling pathways activated by IRS signaling (canonical pathways). However, novel signaling axes involving IRS proteins (noncanonical pathways) have recently been identified in solid tumor and hematologic neoplasm models. Insulin receptor substrate-1 (IRS1) and insulin receptor substrate-2 (IRS2) are the best-characterized IRS proteins in hematologic-related processes. IRS2 binds to important cellular receptors involved in normal hematopoiesis (EPOR, MPL and IGF1R). Moreover, the identification of IRS1/ABL1 and IRS2/JAK2V617F interactions and their functional consequences has opened a new frontier for investigating the roles of the IRS protein family in malignant hematopoiesis. Insulin receptor substrate-4 (IRS4) is absent in normal hematopoietic tissues but may be expressed under abnormal conditions. Moreover, insulin receptor substrate-5 (DOK4) and insulin receptor substrate-6 (DOK5) are linked to lymphocyte regulation. An improved understanding of the signaling pathways mediated by IRS proteins in hematopoiesis-related processes, along with the increased development of agonists and antagonists of these signaling axes, may generate new therapeutic approaches for hematological diseases. The scope of this review is to recapitulate and review the evidence for the functions of IRS proteins in normal and malignant hematopoiesis.

Insulin Substrate Receptor (IRS) proteins in normal and malignant hematopoiesis

The insulin receptor substrate (IRS) proteins are a family of cytoplasmic proteins that integrate and coordinate the transmission of signals from the extracellular to the intracellular environment via transmembrane receptors, thus regulating cell growth, metabolism, survival and proliferation. The PI3K/AKT/mTOR and MAPK signaling pathways are the best-characterized downstream signaling pathways activated by IRS signaling (canonical pathways). However, novel signaling axes involving IRS proteins (noncanonical pathways) have recently been identified in solid tumor and hematologic neoplasm models. Insulin receptor substrate-1 (IRS1) and insulin receptor substrate-2 (IRS2) are the best-characterized IRS proteins in hematologic-related processes. IRS2 binds to important cellular receptors involved in normal hematopoiesis (EPOR, MPL and IGF1R). Moreover, the identification of IRS1/ABL1 and IRS2/JAK2V617F interactions and their functional consequences has opened a new frontier for investigating the roles of the IRS protein family in malignant hematopoiesis. Insulin receptor substrate-4 (IRS4) is absent in normal hematopoietic tissues but may be expressed under abnormal conditions. Moreover, insulin receptor substrate-5 (DOK4) and insulin receptor substrate-6 (DOK5) are linked to lymphocyte regulation. An improved understanding of the signaling pathways mediated by IRS proteins in hematopoiesis-related processes, along with the increased development of agonists and antagonists of these signaling axes, may generate new therapeutic approaches for hematological diseases. The scope of this review is to recapitulate and review the evidence for the functions of IRS proteins in normal and malignant hematopoiesis.

Tumor phylogeny inference using tree-constrained importance sampling.

MOTIVATION: A tumor arises from an evolutionary process that can be modeled as a phylogenetic tree. However, reconstructing this tree is challenging as most cancer sequencing uses bulk tumor tissue containing heterogeneous mixtures of cells. RESULTS: We introduce P robabilistic A lgorithm for S omatic Tr ee I nference (PASTRI), a new algorithm for bulk-tumor sequencing data that clusters somatic mutations into clones and infers a phylogenetic tree that describes the evolutionary history of the tumor. PASTRI uses an importance sampling algorithm that combines a probabilistic model of DNA sequencing data with a enumeration algorithm based on the combinatorial constraints defined by the underlying phylogenetic tree. As a result, tree inference is fast, accurate and robust to noise. We demonstrate on simulated data that PASTRI outperforms other cancer phylogeny algorithms in terms of runtime and accuracy. On real data from a chronic lymphocytic leukemia (CLL) patient, we show that a simple linear phylogeny better explains the data the complex branching phylogeny that was previously reported. PASTRI provides a robust approach for phylogenetic tree inference from mixed samples. AVAILABILITY AND IMPLEMENTATION: Software is available at compbio.cs.brown.edu/software. CONTACT: braphael@princeton.edu. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Clonal conversion of B lymphoid leukemia reveals cross-lineage transfer of malignant states.

Even though leukemia is considered to be confined to one specific hematopoietic cell type, cases of acute leukemia of ambiguous lineage and patients relapsing in phenotypically altered disease suggest that a malignant state may be transferred between lineages. Because B-cell leukemia is associated with mutations in transcription factors of importance for stable preservation of lineage identity, we here investigated the potential lineage plasticity of leukemic cells. We report that primary pro-B leukemia cells from mice carrying heterozygous mutations in either or both the Pax5 and Ebf1 genes, commonly mutated in human leukemia, can be converted into T lineage leukemia cells. Even though the conversion process involved global changes in gene expression and lineage-restricted epigenetic reconfiguration, the malignant phenotype of the cells was preserved, enabling them to expand as T lineage leukemia cells in vivo. Furthermore, while the transformed pro-B cells displayed plasticity toward myeloid lineages, the converted cells failed to cause myeloid leukemia after transplantation. These data provide evidence that a malignant phenotype can be transferred between hematopoietic lineages. This has important implications for modern cancer medicine because lineage targeted treatment of leukemia patients can be predicted to provoke the emergence of phenotypically altered subclones, causing clinical relapse.

Survival trends among 1,325 patients with chronic lymphocytic leukemia seen over the past 40 years in Israel.

In the light of recent data showing survival improvement of patients with chronic lymphocytic leukemia (CLL), we investigated clinical characteristics and survival patterns of patients with CLL over the last 40 years in Israel. Demographic and clinical data collected in the database of the Israeli CLL Study Group were analyzed. Of the 1,325 patients, 221 were diagnosed during the time period 1968-1989, 456 during 1990-1999, and 639 during 2000-2010. There was shift toward older age (median, 71 vs. 68 vs. 66 years) and a higher proportion of patients at Binet stage A at diagnosis (77.6% vs. 66.7% vs. 60.3%) in the more recent time periods. Median survival for the entire cohort was 10.9 years; 12.2 years for patients diagnosed at Binet stage A, 8.5 years for stage B, and 6.4 years for stage C patients. Older age, high-beta 2-microglobulin level, and expression of ZAP-70 predicted shorter survival. There were no apparent changes over time regarding gender, age or different clinical stages. Young patients with Binet stage A had lower life expectancy than the general population; but, in older ages, the survival rates were comparable. There were increased proportions of CLL patients diagnosed in early stages, and, at older age, during the last decades, however, survival rates according to sex, age, or stage remained stable. CLL continues to be an incurable disease affecting survival even in patients diagnosed at early stages. Survival benefit shown in recent trials using chemoimmunotherapy has still to be proven in wider general practice.

Modulation of the poliovirus receptor expression in malignant lymphocytes by epigenetic alterations.

Malignant lymphocytes are characterized by their low expression of poliovirus receptor (PVR), ligand for the activating natural killer (NK) cell receptors, which may explain their insensitivity toward NK cell-based therapeutic approaches. Here, we have studied the mechanism of this defective expression of PVR. We demonstrated that the characterization of NK-insensitive cell lines was of low expression of PVR in both mRNA and surface levels, and that PVR of RAJI cells able to resist NK cells has hypermethylated promoter-associated CpG islands. After treating with 5-azacytidine (5-AZA) (ie, hypomethylation agent) and suberoylanilide hydroxamic acid (SAHA) (ie, histone deacetylase inhibitor), respectively or simultaneously, the abnormal epigenetic status became partly reversed, and the mRNA and surface expression of PVR restored. The expression restoration of the gene enhanced susceptibility of RAJI cells to NK cells but, when the RAJI cells were incubated with the specific blocking antibody for PVR's receptor, the enhanced susceptibility would diminish. Patients with acute myeloid leukemia expressed higher PVR than patients with acute lymphoblastic leukemia in both mRNA and surface levels. Epigenetic modulation of hypermethylation and histone deacetylase is involved in repressing PVR expression in malignant lymphocytes resistant to NK cells.

Adiposity in childhood cancer survivors: insights into obesity physiopathology.

As childhood cancer treatment has become more effective, survival rates have improved, and a number of complications have been described while many of these patients reach adulthood. Obesity is a well-recognized late effect, and its metabolic effects may lead to cardiovascular disease. Currently, studies concerning overweight have focused on acute lymphocytic leukemia and brain tumors, since they are at risk for hypothalamic-pituitary axis damage secondary to cancer therapies (cranial irradiation, chemotherapy, and brain surgery) or to primary tumor location. Obesity and cancer have metabolic syndrome features in common. Thus, it remains controversial if overweight is a cause or consequence of cancer, and to date additional mechanisms involving adipose tissue and hypothalamic derangements have been considered, comprising premature adiposity rebound, hyperinsulinemia, leptin regulation, and the role of peroxisome proliferator-activated receptor gamma. Overall, further research is still necessary to better understand the relationship between adipogenesis and hypothalamic control deregulation following cancer therapy.

[Characteristics of the morphofunctional condition of cell populations by the modal cell class in response to transplantation of lymphocytic leukemia p-388].

On the model of transplanted leukemia p-388, cytophotometry has shown that tumors' impact on the body includes two stages: direct affection of the target organ, indirect affection through changes in functional relations with cell populations of other organs due to the impact of transformed cells of the damaged target organ. Moreover, the progress of tumor growth alters functional relations between the organs.

Adiposity in childhood cancer survivors: insights into obesity physiopathology / Adiposidade em pacientes tratados por câncer na infância: entendendo a fisiopatologia da obesidade

As childhood cancer treatment has become more effective, survival rates have improved, and a number of complications have been described while many of these patients reach adulthood. Obesity is a well-recognized late effect, and its metabolic effects may lead to cardiovascular disease. Currently, studies concerning overweight have focused on acute lymphocytic leukemia and brain tumors, since they are at risk for hypothalamic-pituitary axis damage secondary to cancer therapies (cranial irradiation, chemotherapy, and brain surgery) or to primary tumor location. Obesity and cancer have metabolic syndrome features in common. Thus, it remains controversial if overweight is a cause or consequence of cancer, and to date additional mechanisms involving adipose tissue and hypothalamic derangements have been considered, comprising premature adiposity rebound, hyperinsulinemia, leptin regulation, and the role of peroxisome proliferator-activated receptor γ. Overall, further research is still necessary to better understand the relationship between adipogenesis and hypothalamic control deregulation following cancer therapy.

Os avanços do tratamento contra o câncer infantil têm resultado no aumento da sobrevida e das complicações, à medida que os pacientes atingem a maioridade. A obesidade é um evento reconhecido, e seus efeitos metabólicos levam à doença cardiovascular. Atualmente, o estudo da obesidade tem enfocado a leucemia linfocítica aguda e os tumores cerebrais, já que ambos têm risco para lesões hipotalâmicas, secundárias às terapias (irradiação cranial, quimioterapia, e cirurgia) ou à localização do tumor. Obesidade e câncer têm em comum fatores para síndrome metabólica. Entretanto, a relação de causa e efeito entre obesidade e câncer permanece controversa, sendo que são considerados outros mecanismos envolvendo o tecido adiposo e lesões hipotalâmicas, como o rebote precoce de adiposidade, hiperinsulinemia, regulação da leptina, e o papel do receptor ativado por proliferadores de peroxissoma γ. Concluindo, mais estudos são necessários para entender a relação entre adipogênese e descontrole hipotalâmico em sobreviventes de câncer.

Detection of anti-envoplakin and anti-periplakin autoantibodies by ELISA in patients with paraneoplastic pemphigus.

Paraneoplastic pemphigus patients (PNP) develop a group of autoantibodies, among which those against envoplakin and periplakin are almost always found. Epitope mapping has indicated that the linker subdomains of the proteins harbor the major antigenic sites recognized by PNP sera. In order to detect specific autoantibodies for the diagnosis of PNP, we expressed recombinant proteins containing linker subdomains of human periplakin and envoplakin in a human kidney cell line, and used them as the antigens for ELISAs. We found that all of the sera from 16 PNP patients recognized these two recombinant proteins by ELISA, and sera from 20 pemphigus vulgaris (PV), 12 pemphigus foliaceus (PF), 20 bullous pemphigoid (BP), 2 Castleman's tumor without PNP and 20 normal controls showed negative results. We also expressed the extracellular domain of desmoglein 3 (Dsg3) in the cell line, and used this recombinant Dsg3 as the ELISA antigen. Only 11 of our 16 PNP sera were positive, and most PV sera were positive. Our findings indicate that ELISAs using the recombinant proteins containing linker subdomains of envoplakin and periplakin expressed in a human cell line as the antigens are highly sensitive and specific for the diagnosis of PNP.

Emerging drugs for rarer chronic lymphoid leukemias.

BACKGROUND: Rarer indolent lymphoid leukemias include well defined mature B-cell and T-cell neoplasm with widely varying natural history and specific morphological, immunophenotypic and molecular characteristics. Among these are prolymphocytic leukemia (PLL), hairy cell leukemia (HCL) and its variants, large granular lymphocyte leukemia (LGLL) and adult T-cell leukemia/lymphoma (ATLL). OBJECTIVE: To present current therapies and emerging drugs potentially useful in the treatment of rarer chronic lymphoid leukemias. METHODS: After searching MEDLINE, PubMed and the Current Contents database, and conference proceedings from the previous 3 years of the American Society of Hematology (ASH), the European Society of Hematology (EHA) and the American Society of Clinical Oncology (ASCO) were searched manually; articles written in English and additional relevant publications were then selected. RESULTS/CONCLUSION: New drugs including monoclonal antibodies (mAbs), new purine analogs, small molecules targeting specific molecular targets and other agents are included. Future research should focus on the novel therapeutic strategies based on the molecular pathogenic mechanisms and the development of new targeted therapies for each distinct chronic lymphoid leukemia.

Modeling the initiation and progression of human acute leukemia in mice.

Our understanding of leukemia development and progression has been hampered by the lack of in vivo models in which disease is initiated from primary human hematopoietic cells. We showed that upon transplantation into immunodeficient mice, primitive human hematopoietic cells expressing a mixed-lineage leukemia (MLL) fusion gene generated myeloid or lymphoid acute leukemias, with features that recapitulated human diseases. Analysis of serially transplanted mice revealed that the disease is sustained by leukemia-initiating cells (L-ICs) that have evolved over time from a primitive cell type with a germline immunoglobulin heavy chain (IgH) gene configuration to a cell type containing rearranged IgH genes. The L-ICs retained both myeloid and lymphoid lineage potential and remained responsive to microenvironmental cues. The properties of these cells provide a biological basis for several clinical hallmarks of MLL leukemias.

Autocrine proliferative effect of ghrelin on leukemic HL-60 and THP-1 cells.

Ghrelin is a 28 amino acid peptide hormone that is mainly produced by the stomach, but also by several tissues and tumors. Ghrelin is octanoylated on the Ser(3), but is also detected as a des-acylated form. Only the acylated ghrelin activates the GH secretagogue receptor (GHS-R) type 1a to stimulate GH release, and regulate food intake and energy metabolism. For the first time, we report that ghrelin and des-acyl ghrelin are present in human promyelocytic HL-60, monocytic THP-1 and lymphoblastic SupT1 cell lines. The human leukemic cell lines did not express the functional GHS-R 1a, whereas they expressed GHS-R 1b, a truncated variant of the receptor. Leukemic cell proliferation was not modified by the addition of octanoylated or des-acyl ghrelins. However, THP-1 and HL-60 cell proliferations were inhibited by SB801, an antibody directed against the N-terminal octanoylated portion of ghrelin, suggesting that octanoylated ghrelin stimulates cell proliferation via an autocrine pathway involving an as yet unidentified ghrelin receptor. Both octanoylated and des-acyl ghrelins did not alter the basal adenylate cyclase activity. Treatments of THP-1 and SupT1 cells by both octanoylated and des-acyl ghrelins did not modify the adenylate cyclase activity in response to vasoactive intestinal peptide, suggesting that ghrelin is unlikely to modulate the anti-inflammatory and differentiating properties of vasoactive intestinal peptide.

Caracterización biológica y clínica de pacientes pediátricos con leucemia linfoide aguda pro-B / Biological and clinical characterization of pediatric patients with pro-B acute lymphocytic leukemia

Se estudiaron las características biológicas y clínicas de 19 niños con leucemia linfoide aguda (LLA) pro-B en un periodo de 14 años. El inmunofenotipaje celular se realizó mediante el ultramicrométodo inmunocitoquímico. Se observó una mayor incidencia en el grupo de 2-5 años. La distribución por raza en este trabajo fue la misma que en la población normal. Los niños varones de piel blanca fueron los más afectados. El 73,7 por ciento de los pacientes mostró leucocitos < 20 x109 /L al inicio de la enfermedad y el 57,9 por ciento mostró hepatomegalia y esplenomegalia. Se observaron adenopatías y manifestaciones hemorrágicas en el 47,4 por ciento y en el 2 por ciento, respectivamente. El antígeno CD19 se expresó en el 100 por ciento de los pacientes, el CD22 citoplasmático en el 89,5 por ciento, la enzima Tdt en el 68,4 por ciento y el HLA-DR en el 57,9 por ciento. Del total de pacientes estudiados, 4 (21 por ciento) expresaron antígenos mieloides y fueron clasificados como LLA pro-B Mi+. Los antígenos mieloides expresados fueron, en un paciente el CD13 y CD33 (5,3 por ciento), y el CD15 en 2 enfermos (10,5 por ciento). Estos resultados demuestran que la LLA es una enfermedad heterogénea con subtipos biológicos y clínicos diferentes(AU)

[Spinal subarachnoid hematoma after lumbar puncture in a patient with leukemia: report of a case and review of the literature]. / Hematoma subaracnoideo espinal tras punción lumbar en paciente con leucemia: presentación de un caso y revisión de la literatura.

Acute myeloradicular compression due to a spinal subarachnoid hematoma (SSAH) after lumbar puncture (LP) is an extremely rare complication. Several risk factors have been involved in the production of these hematomas, mainly the presence of hemostasis disorders in the patient. We report the case of a 20-year-old man with leukemia and thrombocytopenia (26,000 platelets/mm(3)) who, after undergoing a LP, developed paraparesis and became unable to stand. A magnetic resonance disclosed the presence of a ventral intradural hematoma from D12 to L4. An emergency decompressive laminectomy was performed and a hematoma located in the subarachnoid space was partially removed. On the fourth postoperative day, the patient was able to walk without assistance, but one month later, he died because of systemic complications of his disease. Only 26 cases of SSAH after LP have been found in the literature review we have performed. In most of them, the following common features have been observed: association with anticoagulant therapies, association with thrombocytopenia, delayed onset of compressive myeloradicular syndrome, need of surgical treatment, good functional outcome in half of patients, and short life expectancy for patients with previous serious illness. Risk for developing a SSAH after LP could be high in leukemia patients with a tendency to have severe thrombocytopenia (perhaps less than 25,000 platelets/mm(3)).

[Circulating endothelial cells, endothelial precursors, VEGF and bFGF concentrations in patients with acute leukemias, lymphomas and myelomas]. / Krazace komórki sródblonka, prekursory sródblonka oraz stezenie VEGF i bFGF u chorych na ostre bialaczki, chloniaki i szpiczaki.

Circulating endothelial cells and their precursors are suggested by some authors to be novel markers of angiogenesis. The aim of the study was to measure circulating endothelial cells (CEC), circulating endothelial precursors (CEP) and activated endothelial cells (aCEC) and serum concentrations of VEGF (vascular endothelial growth factor) and bFGF (basic fibroblast growth factor), well-known proangiogenic factors in patients with haematological malignancies before and after chemotherapy. Measurements were carried out in 20 patients with acute leukemia, 21 with malignant lymphoma and with 20 with multiple myeloma. The number of CEC, CEP and aCEC was measured by means of 3-color flow cytometry and serum concentrations of VEGF and bFGF with ELISA. In patients with acute leukemias and lymphomas the number of CEC was significantly higher than in controls, and that high number correlated with worse prognosis in patients with lymphomas. The increased number of CEP at diagnosis in patients with acute leukemia and lymphoma correlated with worse prognosis. The number of aCEC was higher in leukemic and lymphoma groups. After chemotherapy the decrease in CEC and CEP numbers in patients with acute leukemia and lymphoma was observed. In patients with lymphoma the increased serum VEGF concentrations in comparison with healthy subjects were noted but in leukemic patients-lower concentrations of VEGF. The initial high concentrations of bFGF in all patients did not change after therapy and in patients with lymphoma correlated with worse prognosis. Results suggest that in patients with acute leukemias and lymphomas CEC and CEP may be the markers of malignant process correlating with clinical outcome. aCEC may have a similar role in both diseases. Also in patients with lymphoma VEGF may be a marker of disease activity. bFGF is connected with pathogenesis of acute leukemia, myeloma and lymphoma and in patients with lymphoma is a predictor of worse prognosis.

Hematoma subaracnoideo espinal tras punción lumbar en paciente con leucemia. Presentación de un caso y revisión de la literatura / Spinal subarachnoid hematoma after lumbar puncture in a patient with leukemia. Report of a case and review of the literature

La compresión mielo-radicular aguda secundaria a un hematoma subaracnoideo espinal (HSAE) es una complicación extremadamente rara tras una punción lumbar (PL). En el mecanismo de producción de estos hematomas han sido implicados diversos factores de riesgo, principalmente la presencia de trastornos de la hemostasia en el paciente. Presentamos el caso de un varón de 20 años con leucemia aguda y trombocitopenia (26.000 plaquetas/mm3) que, tras ser sometido a una PL, desarrolló una paraparesia con imposibilidad para la bipedestación. La resonancia magnética (RM) demostró la presencia de un hematoma intradural ventral desde D12 hasta L4. Se realizó una laminectomía descompresiva de urgencia y se pudo evacuar parcialmente un hematomalocalizado en el espacio subaracnoideo. Al cuarto día postoperatorio, el paciente consiguió caminar sin ayuda, pero falleció un mes después debido a complicacionessistémicas de su enfermedad. Sólo se han encontrado 26 casos de HSAE tras PL en la revisión de la literatura que hemos realizado. Se han observado las siguientes características comunes a la mayoría de ellos: asociación con tratamientos anticoagulantes, asociación con trombocitopenia, apariciónde síndrome compresivo mielo-radicular de forma retardada, necesidad de tratamiento quirúrgico, buen resultado funcional en la mitad de los pacientes, y corta esperanza de vida en aquellos con enfermedad previa grave. En pacientes leucémicos con tendencia a tener marcada trombocitopenia (quizás por debajo de 25.000 plaquetas/mm3), el riesgo de desarrollar un HSAE tras PL puede ser elevado

Acute myeloradicular compression due to a spinal subarachnoid hematoma (SSAH) after lumbar puncture(LP) is an extremely rare complication. Several risk factors have been involved in the production of these hematomas, mainly the presence of hemostasis disorders in the patient. We report the case of a 20-year-old man with leukemiaand thrombocytopenia (26.000 platelets/mm3) who, after undergoing a LP, developed paraparesis and became unable to stand. A magnetic resonance disclosedthe presence of a ventral intradural hematoma from D12 to L4. An emergency decompressive laminectomy was performed and an hematoma located in the subarachnoidspace was partially removed. On the fourth postoperative day, the patient was able to walk without assistance, but one month later, he died because of systemiccomplications of his disease. Only 26 cases of SSAH after LP have been found in the literature review we have performed. In most of them, the following common features have been observed: association with anticoagulant therapies, association with thrombocytopenia, delayed onset of compressive myeloradicular syndrome, need of surgical treatment, good functional outcome in half of patients, and short life expectancy for patients with previous serious illness. Risk for developing a SSAH after LP could be high in leukemia patients with a tendency to have severe thrombocytopenia (perhaps less than 25.000 platelets/mm3)

Significance of chemokine receptor expression in aggressive NK cell leukemia.

Natural killer (NK) cell-type lymphoproliferative diseases of granular lymphocytes can be subdivided into aggressive NK cell leukemia (ANKL) and chronic NK cell lymphocytosis (CNKL). One reason for the poor outcome in ANKL is leukemic infiltration into multiple organs. The mechanisms of cell trafficking associated with the chemokine system have been investigated in NK cells. To clarify the mechanism of systemic migration of leukemic NK cells, we enrolled nine ANKL and six CNKL cases, and analyzed the expression profiles and functions of chemokine receptors by flowcytometry and chemotaxis assay. CXCR1 was detected on NK cells in all groups, and CCR5 was positive in all ANKL cells. Proliferating NK cells were simultaneously positive for CXCR1 and CCR5 in all ANKL patients examined, and NK cells with this phenotype did not expand in CNKL patients or healthy donors. ANKL cells showed enhanced chemotaxis toward the ligands of these receptors. These results indicated that the chemokine system might play an important role in the pathophysiology of ANKL and that chemokine receptor profiling might be a novel tool for discriminating ANKL cells from benign NK cells.

Effect of antioxidant vitamins on radiation-induced apoptosis in cells of a human lymphoblastic cell line.

Modulating the amount of radiation-induced apoptosis by administering antioxidant vitamins offers a possible way to influence radiation-induced side effects in normal tissues. Therefore, we investigated the effect of beta-carotene, vitamin C and alpha-tocopherol on radiation-induced apoptosis in cells in culture. Human T-lymphoblastic MOLT-3 cells were irradiated with a dose of 3 Gy 1 h after or immediately prior to the addition of vitamins in three concentrations (0.01 microM, 1 microM and 100 microM). Eight hours later, apoptosis was scored morphologically by staining the nuclear DNA with Hoechst 33342. When given prior to irradiation, beta-carotene and vitamin E reduced the amount of radiation-induced apoptosis significantly at concentrations of 0.01 microM and 1 microM. In contrast, vitamin C did not show any protective effect when given at these two concentrations and caused a slight but significant radiosensitization at 100 microM. At 0.01 microM, all combinations of two vitamins showed a protective effect. This was also observed for the combination of all three vitamins at concentrations of 0.01 and 1 microM. When given immediately after irradiation, each of the three vitamins showed a protective effect at 0.01 microM. In addition, the combination of alpha-tocopherol and vitamin C reduced radiation-induced apoptosis slightly when given at 1 microM. In all other cases, no statistically significant modulation of radiation-induced apoptosis was observed. In our experimental system, the protective effect of beta-carotene and vitamin E was dependent on concentration and occurred only in the micromolar and sub-micromolar concentration range, while vitamin C alone, but not in combinations, had a sensitizing effect, thus arguing for a careful consideration of vitamin concentrations in clinical settings.