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Michael Lishner

Publications and source records attributed to Michael Lishner.

33 records · Page 2Linked to original sources
PubMed2004

Simvastatin induces death of multiple myeloma cell lines.

BACKGROUND: Accumulating reports indicate that statins widely prescribed for hypercholesteromia have antineoplastic activity. We hypothesized that because statins inhibit farnesylation of Ras that is often mutated in multiple myeloma (MM), as well as the production of interleukin (IL)-6, a key cytokine in MM, they may have antiproliferative and/or proapoptotic effects in this malignancy. METHODS: U266, RPMI 8226, and ARH77 were treated with simvastatin (0-30 microM) for 5 days. The following aspects were evaluated: viability (IC50), cell cycle, cell death, cytoplasmic calcium ion levels, supernatant IL-6 levels, and tyrosine kinase activity. RESULTS: Exposure of all cell lines to simvastatin resulted in reduced viability with IC50s of 4.5 microM for ARH77, 8 microM for RPMI 8226, and 13 microM for U266. The decreased viability is attributed to cell-cycle arrest (U266, G1; RPMI 8226, G2M) and cell death. ARH77 underwent apoptosis, whereas U266 and RPMI 8226 displayed a more necrotic form of death. Cytoplasmic calcium levels decreased significantly in all treated cell lines. IL-6 secretion from U266 cells was abrogated on treatment with simvastatin, whereas total tyrosine phosphorylation was unaffected. CONCLUSIONS: Simvastatin displays significant antimyeloma activity in vitro. Further research is warranted for elucidation of the modulated molecular pathways and clinical relevance.

Anticholesteremic Agents↗
PubMed2004

Impact and treatment of cancer during pregnancy.

Cancer is the second most common cause of death in the reproductive years and complicates up to one in 1000 pregnancies. When cancer is diagnosed during pregnancy, the management strategy must take into account both the mother and developing fetus. In this article, the four most common malignancies diagnosed in pregnant patients--cervical and breast cancer, malignant melanoma and lymphoma--will be reviewed, with an emphasis on the impact of the diagnosis and management on the pregnant patient and the developing fetus.

Adult↗
PubMed2004

[Composition of risk factors among acute myocardial infarction patients in Israel: sub-analysis of the Israeli National Prospective Survey on Acute Myocardial Infarction in 2000].

BACKGROUND: Risk factor modification has been shown to reduce cardiovascular morbidity and mortality. Nevertheless, there is a debate regarding the relative importance of risk factors when analyzed by age, gender and ethnical background. The aim of the study was to define sub-populations with different classes of risk factors that may enable targeted and improved preventive approaches. METHODS: The study is a sub-analysis of the Israeli National Prospective Survey on Acute Myocardial Infarction in the year 2000. We evaluated the interactions between the classical risk factors and their correlation with the patients' age and gender. RESULTS: A total of 1,683 patients with acute myocardial infarction were hospitalized in 26 hospitals in Israel during February and March 2000. Seventy-three percent were men and 27% were women and their mean age was 66 +/- 13 years. Younger patients had significantly more risk factors than the older ones (P < or = 0.0001). Women were significantly older and had less risk factors than males (73 +/- 12 vs. 63 +/- 14, P < 0.01; 2.02 +/- 1.10 vs. 1.84 +/- 1.03, P < or = 0.002, respectively). One hundred and twenty-eight patients (7.8%) had no risk factors. Hyperlipidemia, current smoking and family history were common in younger patients, while hypertension and diabetes mellitus were more common in the older ones. Family history and smoking were significantly more common in males, whereas diabetes mellitus and hypertension were more common in females. CONCLUSIONS: There were defined sub-populations with different risk factors for acute myocardial infarction. Our findings suggest that in young patients cessation of smoking and control of hyperlipidemia are of crucial importance. Hypertension and diabetes mellitus are more common in women and older patients and their impact on the atherosclerotic process is gradual and manifests later in life. Further studies should clarify the relative importance of each risk factor and its control.

Adult↗
PubMed2003

Simvastatin induces apoptosis of B-CLL cells by activation of mitochondrial caspase 9.

BACKGROUND AND OBJECTIVES: Chronic lymphocytic leukemia (CLL) is the most common leukemia in the western world. Despite several advances in therapeutic options, the disease remains incurable. Recently, it was repeatedly demonstrated that statins, competitive inhibitors of 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase, have antineoplastic effects. Therefore we aimed to study the effects of simvastatin (Sim) on malignant B cells derived from patients with CLL and mechanisms of action of the drug. METHODS AND RESULTS: Purified B-CLL cells from 15 patients were cultured either alone or with Sim at concentrations of 10, 50, and 100 microM. Viability, measured by the activity of mitochondrial dehydrogenases, was reduced significantly in the cells treated with Sim at 50 and 100 microM for 24 hours (p<0.005). The level of apoptosis, as measured by annexin binding to exposed phosphatidylserine moieties, increased significantly in the treated cells at concentrations higher than 50 microM for 24 hours (p<0.003). The level of necrosis, as measured by propidium iodide internalization, increased significantly after 24 hours exposure to Sim at 50 microM (p<0.01). The apoptotic cascade was studied by immunoblot analysis of caspases following Sim treatment. These showed cleavage of caspases 9, 8, and 3. Addition of the caspase inhibitor Z-VAD.fmk inhibited caspase 8 and 3 significantly but did not affect caspase 9. CONCLUSION: Exposure of clonal B lymphocytes from patients with CLL to simvastatin decreases viability significantly by the induction of apoptosis. The apoptosis induced by Sim is probably initiated by the mitochondrial caspase 9, which indirectly leads to activation of caspase 3 and 8.

Apoptosis↗
PubMed2003

Initial exposed phosphatidylserine levels correlate with cellular response to cytotoxic drugs.

Phosphatidylserine's (PS) membranal distribution is associated with an expanding variety of biological processes. We studied the relevance of preliminarily exposed membranal PS levels to cellular effects of cytotoxic agents. PBL of normal controls (n = 18) and patients with doxorubicin-treated breast carcinoma (n = 27) or 5'-fluorouracil-treated colorectal cancer (n = 32) were assayed before and after drug infusion. Membranal expression levels of PS, adhesion molecules (CD18, CD11a-c, CD63) and Fas-R of leukocyte subtypes were assessed by flow cytometer. Statistical analysis was implemented. Our results demonstrate external expression of PS on all leukocyte subpopulations despite non-apoptotic light scatter characteristics. Several distinct features were observed of which the more prominent were: leukocyte subtypes each display characteristic PS levels; cancer patients' PBL display higher preliminary PS levels than normal controls in all cell groups; and existence of negative correlations between initial membranal PS levels and drug-induced changes in its expression. Our findings underscore the complex involvement of PS in PBL apoptosis and possibly drug resistance.

Aged↗
PubMed2003

The antiapoptotic effects of blood constituents in patients with chronic lymphocytic leukemia.

OBJECTIVE: Clonal B-lymphocytes of chronic lymphocytic leukemia (B-CLL) are characterized by decreased sensitivity to programmed cell death and, therefore, they accumulate in vivo. However, these malignant cells die rapidly in vitro. In the current study we concentrated on the contribution of autologous serum (AS) and lymphocyte subsets to the survival of the malignant cells in vitro. METHODS: Mononuclear cells from the peripheral blood of 26 CLL patients and 24 controls were incubated overnight in the presence or absence of AS and heat-inactivated AS (HI-AS) or fetal calf serum (FCS). Also, isolated B cells were incubated at different concentrations in the presence of AS and/or isolated T cells. The level of apoptosis of CD19+ cells was measured by flow cytometry. RESULTS: Spontaneous apoptosis of unfractionated B-CLL cells incubated with AS, FCS or without serum was significantly lower than the rate of B-cell death in the control group, in similar culture conditions. AS had an antiapoptotic effect on unfractionated B-CLL cells when compared with FCS. The rate of apoptosis of B-CLL cells was directly associated with stage. HI of AS had a variable effect, which was related to the stage of the disease. High concentrations of B cells and the addition of autologous T cells reduced the rate of apoptosis when incubated without serum. The antiapoptotic effect of T cells was most prominent in progressive stages. CONCLUSIONS: B-CLL cells exhibit decreased spontaneous apoptosis, which is partially prevented by humoral (AS) and cellular (T cells and B-CLL cells) factors. The equilibrium between apoptotic and antiapoptotic factors changes with disease progression.

Aged↗
PubMed2003

Granulocyte colony-stimulating factor administration upregulates telomerase activity in CD34+ haematopoietic cells and may prevent telomere attrition after chemotherapy.

Hematopoietic reconstitution could be associated with premature ageing of the transplanted cells and a high frequency of myelodysplastic syndrome and secondary leukaemia. Telomere length decreases with cell divisions and age, and at a crucial length it is associated with chromosomal instability and cell senescence. Telomerase is a reverse transcriptase enzyme that adds nucleotides to chromosomal ends. Most somatic cells lack telomerase activity yet haematopoietic stem cells retain low levels of telomerase. Some studies have found that chemotherapy and stem cell transplantation lead to the accelerated shortening of telomere length. As granulocyte colony-stimulating factor (G-CSF) is routinely used in the mobilization of stem cells for transplantation, we evaluated its effects on telomerase activity and regulation, and on telomere dynamics, in normal donors and selected lymphoma patients. Administration of G-CSF increased telomerase activity in CD34+ haematopoietic cells compared with controls. In marrow-derived CD34+ cells, telomerase activity increased sevenfold, compared with a 14-fold increase in peripheral-blood-mobilized CD34+ cells. A parallel increase in the expression of human telomerase enzyme reverse transcriptase RNA and protein kinase C alpha occurred. In addition, G-CSF administration to five lymphoma patients after consecutive courses of CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy, resulted in telomere length preservation or elongation, as opposed to marked attrition in patients who did not receive growth factors. We conclude that the in vivo administration of G-CSF prevents or attenuates telomere attrition associated with chemotherapy administration. This attenuation may contribute to the preservation of telomere integrity inG-CSF-primed transplanted stem cells.

Aged↗
PubMed2003

The effects of doxorubicin on apoptosis and adhesion molecules of normal peripheral blood leukocytes-an ex vivo study.

This ex vivo study was designed to evaluate the effect of doxorubicin (Dox) on normal peripheral blood leukocytes (PBL) in terms of apoptosis and membranal expression levels of adhesion molecules. Blood was drawn immediately prior to and after Dox administration from 21 breast cancer patients, and incubated at room temperature for 24 h. Flow cytometry was employed in analysis of apoptosis with Annexin-V and protein membranal expression levels with monoclonal antibodies to CD49d, CD18, CD11a-c and CD63. Dox induced statistically significant apoptosis in all three major PBL subpopulations (p<0.01). Between 70 and 90% of samples underwent apoptosis in all PBL subgroups. No significant change was observed in the membranal level of CD63, CD49d and CD11a-c after chemotherapy in any PBL subpopulation. However, a significant reduction in the membranal level of CD18 was demonstrated in polymorphonuclear cells after Dox (p<0.005) both in apoptotic and non-apoptotic cells (p<0.05), suggesting a direct effect of Dox rather than an apoptosis-associated phenomenon. We observed the expected leukopenia 10 days after Dox administration with no correlation to apoptosis, suggesting that leukopenia by Dox is largely attributed to toxicity of blood progenitors.

Adult↗
PubMed2003

Thalidomide down-regulates transcript levels of GC-rich promoter genes in multiple myeloma.

Thalidomide (Thd), a potent teratogen, was shown to have therapeutic potential in cancer, primarily in multiple myeloma (MM), yet its mechanism of action has not been elucidated. It was recently suggested that its teratogenicity is derived from interference in expression of genes regulated by GC-rich promoters by blocking the binding of SP1 transcription factor to its motif. We explored the validation of the proposed model by focusing on potential molecular targets associated with MM pathogenesis. Cell lines RPMI 8226, U266, and ARH-77 were exposed for 24 h to racemic Thd and analyzed for apoptosis, membranal expression of CD29 and CD63, transcript level of hTERT, CD63, and IGFI-R (characterized by GC-rich motifs) and telomerase activity. Analysis of an hTERT core promoter reporter gene expression [enhanced green fluorescent protein (EGFP)] in transiently transfected RPMI 8226 incubated with racemic and steric (+/-)-enantiomers of Thd was performed. A consistent reduction ( approximately 10-40%) in transcript levels of all three assayed genes in all three cell lines was demonstrated in the presence of racemic Thd. Significant reduction of EGFP was demonstrated in cells transfected with hTERT reporter gene and treated with racemic and (S)-Thd. Our results show that Thd's antimyeloma activity can be ascribed to the same mechanism responsible for its teratogenic effect and that the inhibition of GC-rich promoter genes is mostly attributed to the S-racemate. Indeed, this selectivity delineates GC-rich promoter genes as a unique group eligible for specific drug targeting.

Adenomatous Polyposis Coli Protein↗
PubMed2003

Taking bisphosphonates during pregnancy.

QUESTION: Several of my female patients take bisphosphonates for low bone mineral density (BMD). Two of them are of reproductive age. Are these drugs safe during pregnancy? ANSWER: Very little is currently known about the effects of bisphosphonates on human pregnancy. There have been only two reports of bisphosphonate use during late pregnancy. Animal studies suggest that biphosphonates cross the placenta and that the effect is an extension of the expected pharmacologic effect of bisphosphonates on both fetus and mother. Risks and benefits should be carefully weighed.

Animals↗
PubMed2002

Detection of relapse in non-Hodgkin's lymphoma: role of routine follow-up studies.

Complete remission can be achieved in 60-80% of adults with diffuse aggressive non-Hodgkin's lymphoma. However, 20-40% of them will subsequently relapse. Nevertheless, formal follow-up guidelines for recurrence detection have never been advocated. We analyzed the pattern of relapse in 30 patients with intermediate- and high-grade non-Hodgkin's lymphoma and the value of intensive protocol for relapse detection. This protocol includes frequent follow-up visits, complete blood count, and serum LDH tests along with annual chest, abdominal, and pelvic CT scans. The median duration of complete remission was 12 months. Twenty-five relapses (83%) were suspected after an interim history and/or physical examination, whereas only 5 relapses (17%) were detected by routine radiographic or laboratory follow-up studies. The majority of relapses (19/30) were detected in sites that included the sites of prior disease. For the first 12 months of complete remission, the estimated cumulative save in charge for a follow-up strategy, based on regular visits in the hematology clinic and performing laboratory and radiologic studies as clinically indicated, is 44% of the cost of a routine intensive evaluation. A reliable and cost-effective follow-up method for non-Hodgkin's lymphoma patients in complete remission should include frequent history and physical examination. Complementary studies should be performed according to clinical indications.

Aged↗
PubMed2002

Replication status in leukocytes of treated and untreated patients with polycythemia vera and essential thrombocytosis.

The replication status of malignant cells is usually asynchronous. However, to date the pattern of replication has not been studied in myeloproliferative disorders nor has the effect of chemotherapy been systematically evaluated. Therefore, we used fluorescence in situ hybridization to interphase nuclei in PHA-stimulated peripheral blood lymphocytes to examine replication timing of three alleles associated with the malignant process. The study group comprised hydroxyurea treated and untreated patients with essential thrombocytosis (ET) or polycythemia vera (PV). A significantly higher rate of the asynchronous pattern of replication in both treated and untreated patients was found as compared to healthy controls. The highest rate of asynchronous replication was observed in untreated patients. Also, the frequency of the two doublets pattern was significantly higher in the untreated group compared to the treated patients and to the control groups. In conclusion, patients with PV and ET have a higher rate of asynchronous pattern of replication. A possible correlation between disease activity and the pattern of replication is suggested. The effect of hydroxyurea on the pattern of replication is variable.

Adult↗
PubMed2002

Allele-specific replication associated with aneuploidy in blood cells of patients with hematologic malignancies.

We hypothesize that coordination between the two DNA parental sets in somatic cells is essential for the stability of the diploid genome, and that its disruption is associated with the many alterations observed in the various cancerous phenotypes. As coordination between two allelic counterparts is well exemplified by synchrony in replication timing, we examined, in blood cells of patients suffering from various hematologic malignancies, replication patterns of five loci. These loci were three cancer-implicated genes (TP53, AML1, and RB1) and two nontranscribed sequences engaged in chromosome segregation. All five loci normally display synchrony in allelic replication timing. In addition, in order to exemplify an asynchronous mode of allelic replication, we followed the replication of allelic counterparts of an imprinted gene (SNRPN), which is distinguished by its asynchronous mode of allelic replication (allele-specific replication). Allelic replication patterns were studied by fluorescence in situ hybridization (FISH), which has been shown to distinguish between nonreplicated and replicated regions of the genome in interphase cells, based on the structure of the specific hybridization signals that are being detected. Using the FISH replication assay we observed, for all loci which normally exhibit synchrony in allelic replication, loss of synchrony when present in blood cells of patients with hematologic malignancies. The loss of synchrony in allelic replication in patients' cells was accompanied by aneuploidy (chromosome losses and gains), the hallmark of cancer. We were able to reinstate the normal pattern of replication in the patients' cells by introducing an inhibitor of DNA methylation. It thus appears loss of allelic coordination is an epigenetic alteration characterizing cancer, which is easily identified by simple cytogenetic means and has a potential use in both cancer investigation and detection.

Adolescent↗
PubMed2002

The role of glucocorticoids in the treatment of fulminant hepatitis induced by dacarbazine.

Dacarbazine (DTIC) is commonly used for the treatment of malignant melanoma and Hodgkin's disease. A very rare complication of this cytotoxic agent is acute vascular hepatic damage, e.g. veno-occlusive disease or Budd-Chiari syndrome. The pathophysiological mechanism involved seems to be an immune reaction. This complication is frequently fatal. We report a patient who developed severe hepatic failure following DTIC treatment who responded favorably to treatment with glucocorticosteroid.

Aged↗