Analysis of the effects of tumor necrosis factor inhibitors on human hematopoiesis

Pharmaceutical aspects of anti-inflammatory TNF-blocking drugs

Tumor necrosis factor (TNF) is a key regulator of inflammatory processes in several immune-mediated inflammatory diseases such as rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, ulcerative colitis, psoriasis and psoriatic arthritis. Inactivating TNF has been found to be a plausible approach in treating these conditions. Two major strategies have been adopted by scientists to inactivate TNF: one is to use monoclonal antibodies (mAbs) that bind to TNF, and the other is to use fusion proteins that bind to TNF, both inactivate TNF and help to prevent TNF-mediated inflammatory processes. Monoclonal antibodies (mAbs) are biological products that selectively bind to specific antigen molecules, and fusion proteins are soluble receptors that bind to TNF. These types of drugs are generally known as biologics and there has been an explosion in the development and testing of biologics since the 1994 US approval and launch of abciximab, a mAb that binds to GPIIb/IIIa on platelets. Anti-TNF drugs that are currently approved by FDA for treating inflammatory conditions include adalimumab, certolizumab pegol, golimumab, infliximab and etanercept. Since these agents are complex protein molecules, the pharmacodynamics and pharmacokinetics of these drugs are different from small-molecule anti-inflammatory agents. This review focuses on the pharmaceutical aspects of these drugs such as mechanism of action, adverse effects, pharmacokinetics and drug interactions. An effort was also taken to compare the pharmacodynamics and pharmacokinetic properties of these drugs, with the available data at this time.

Human CD34+ cells in experimental myocardial infarction: long-term survival, sustained functional improvement, and mechanism of action

RATIONALE

Human CD34(+) cells have been used in clinical trials for treatment of myocardial infarction (MI). However, it is unknown how long the CD34(+) cells persist in hearts, whether the improvement in cardiac function is sustained, or what are the underlying mechanisms.

OBJECTIVE

We sought to track the fate of injected human CD34(+) cells in the hearts of severe combined immune deficiency (SCID) mice after experimental MI and to determine the mechanisms of action.

METHODS AND RESULTS

We used multimodality molecular imaging to track the fate of injected human CD34(+) cells in the hearts of SCID mice after experimental MI, and used selective antibody blocking to determine the mechanisms of action. Bioluminescence imaging showed that injected CD34(+) cells survived in the hearts for longer than 12 months. The PET signal from the injected cells was detected in the wall of the left ventricle. Cardiac MRI showed that left ventricular ejection fraction was significantly improved in the treated mice compared to the control mice for up to 52 weeks (P<0.05). Furthermore, treatment with anti-alpha4beta1 showed that generation of human-derived cardiomyocytes was inhibited, whereas anti-vascular endothelial growth factor (VEGF) treatment blocked the production of human-derived endothelial cells. However, the improvement in cardiac function was abolished only in the anti-VEGF, but not anti-alpha4beta1, treated group.

CONCLUSIONS

Angiogenesis and/or paracrine effect, but not myogenesis, is responsible for functional improvement following CD34(+) cells therapy.

Peripheral blood and bone marrow TNF and TNF receptors in early and advanced stages of B-CLL in correlation with ZAP-70 protein and CD38 antigen

The aim of the study was to evaluate TNF and TNF receptor levels in peripheral blood (PB) and bone marrow (BM) in correlation with clinical and laboratory parameters of B-CLL patients. TNF concentration was significantly higher in BM than in PB. In B-CLL patients elevated TNF and sTNF-RII plasma levels had a high correlation with adverse prognostic factors such as ZAP-70 and CD38. Moreover, the percentage of TNF-producing T cells was significantly higher in ZAP-70-positive comparing to ZAP-70-negative patients. TNF and sTNF-RII plasma levels were higher in the group of patients requiring treatment comparing to the patients who did not.

WP1066 disrupts Janus kinase-2 and induces caspase-dependent apoptosis in acute myelogenous leukemia cells

Several cytokines and growth factors that stimulate the proliferation of acute myelogenous leukemia (AML) cells transduce their signals by activating the transcription factor Janus-activated kinase 2 (JAK2). Accordingly, the inhibition of JAK2 or of its downstream signaling pathways suppresses the proliferation of AML cells. Because (E)-3(6-bromopyridin-2-yl)-2-cyano-N-((S0-1-phenylethyl)acrylamide) (WP1066) is a novel analogue of the JAK2 inhibitor AG490, we tested its activity in AML cells and investigated its mechanism of action. Using clonogenic assays, we found that although WP1066 had a marginal effect on normal marrow progenitors, it inhibited the proliferation of AML colony-forming cells obtained from patients with newly diagnosed AML and that of the AML cell lines OCIM2 and K562. WP1066 inhibited OCIM2 cell multiplication by inducing accumulation of cells at the G(0)-G(1) phase of the cell cycle. Similar to its parent compound AG490, WP1066 inhibited the phosphorylation of JAK2, but unlike AG490, WP1066 also degraded JAK2 protein, thereby blocking its downstream signal transducer and activator of transcription (STAT) and phosphoinositide-3-kinase pathways. These effects resulted in the activation of the caspase pathway. Incubation of both OCIM2 and K562 cells with WP1066 activated caspase-3, induced cleavage of poly(ADP-ribose) polymerase, and caused caspase-dependent apoptotic cell death. Thus, WP1066 is a potent JAK2 inhibitor whose effects in AML and other hematologic malignancies merit further investigation.

Tumor necrosis factor alpha enhances the adenoviral transduction of CD34+ hematopoietic progenitor cells

The purpose of this study was to improve the transduction efficiency of adenoviral vectors (Ad) in human CD34+ hematopoietic progenitor cells. CD34+ cells from cord blood or mobilized peripheral blood were incubated with tumor necrosis factor-alpha (TNF-alpha). After removal of free TNF-alpha, the cells were infected with an Ad encoding green fluorescent protein (GFP). One day later, viable cells were counted and analyzed for GFP and CD34 by flow cytometry. To visualize vectoral trafficking, CD34+ cells were incubated with fluorophore-conjugated Ad. Plating efficiencies of hematopoietic progenitors before and after transduction were evaluated by methylcellulose assays. Pretreatment with TNF-alpha increased the transduction efficiency more than twofold (39.2% versus 15.5%) in a dose-dependent manner and strongly improved the survival of GFP-positive CD34+ cells. Time course experiments showed that TNF-alpha incubation times as short as 10 minutes were still effective. Neutralizing antibodies to TNF receptor II and RGD peptides diminished the TNF-alpha-dependent increase in transduction efficiency. No TNF-alpha-dependent increase in adenoviral receptors (coxsackie-adenovirus receptor, alphavbeta3-integrin) occurred. Analysis of viral binding demonstrated a significantly higher incidence of local concentrations of Ad along the cell surface (caps) in virus-positive cells of the TNF-alpha-treated group. Plating efficiency, especially the formation of granulocyte-macrophage colony forming units, was enhanced by TNF-alpha pretreatment. We conclude that brief incubation with TNF-alpha before addition of the Ad significantly increased the Ad transduction efficiency in CD34+ cells, and improved post-transduction survival of progenitors of the granulocyte-macrophage lineage. This finding correlates with increased Ad capping at the cell surface and suggests an alteration of Ad trafficking.

Both Cell Fusion and Transdifferentiation Account for the Transformation of Human Peripheral Blood CD34-Positive Cells Into Cardiomyocytes In Vivo

Background— Adult human peripheral blood CD34-positive (CD34 + ) cells appear to transform into cardiomyocytes in the injured hearts of severe combined immunodeficient mice. It remains unclear, however, whether the apparent transformation is the result of transdifferentiation of the donor stem cells or of fusion of the donor cell with the cardiomyocyte of the recipients.

Methods and Results— We performed flow cytometry analyses of cells isolated from the hearts of mice that received human CD34 + cells. Human HLA-ABC antigen and cardiac troponin T or Nkx2.5 were used as markers for cardiomyocytes derived from human CD34 + cells, and HLA-ABC and VE-cadherin were used to identify the transformed endothelial cells. The double-positive cells were collected and interphase fluorescence in situ hybridization was used to detect the expression of human and mouse X chromosomes in these cells. We found that 73.3% of nuclei derived from HLA + and troponin T + or Nkx2.5 + cardiomyocytes contain both human and mouse X chromosomes and 23.7% contain only human X chromosome. In contrast, the nuclei of HLA − , troponin T + cells contain only mouse X chromosomes. Furthermore, 97.3% of endothelial cells derived from CD34 + cells contained human X chromosome only.

Conclusions— Thus, both cell fusion and transdifferentiation may account for the transformation of peripheral blood CD34 + cells into cardiomyocytes in vivo.

Transdifferentiation of human peripheral blood CD34+-enriched cell population into cardiomyocytes, endothelial cells, and smooth muscle cells in vivo

BACKGROUND

Adult human peripheral blood cells have been shown to differentiate into mature cells of nonhematopoietic tissues, such as hepatocytes and epithelial cells of the skin and gastrointestinal track. We investigated whether these cells could also transdifferentiate into human cardiomyocytes, mature endothelial cells, and smooth muscle cells in vivo.

METHODS AND RESULTS

Myocardial infarction was created in SCID mice by occluding the left anterior descending coronary artery, after which adult peripheral blood CD34+ cells were injected into the tail vein. Hearts were harvested 2 months after injection and stained for human leukocyte antigen (HLA) and markers for cardiomyocytes, endothelial cells, and smooth muscle cells. Cardiomyocytes, endothelial cells, and smooth muscle cells that bear HLA were identified in the infarct and peri-infarct regions of the mouse hearts. In a separate experiment, CD34+ cells were injected intraventricularly into mice without experimental myocardial infarction. HLA-positive myocytes and smooth muscle cells could only be identified in 1 of these mice killed at different time points.

CONCLUSIONS

Adult peripheral blood CD34+ cells can transdifferentiate into cardiomyocytes, mature endothelial cells, and smooth muscle cells in vivo. However, transdifferentiation is augmented significantly by local tissue injury. The use of peripheral blood CD34+ cells for cell-based therapy should greatly simplify the procurement of cells for the regeneration of damaged myocardium.

The clinical significance of tumor necrosis factor-α plasma level in patients having chronic lymphocytic leukemia

Tumor necrosis factor-α (TNF-α), a cytokine possessing pleiotropic biological activities, is produced by leukemic lymphocytes in patients with chronic lymphocytic leukemia (CLL) and acts as an autocrine and paracrine growth factor in this disease. In this study, TNF-α levels were determined in 150 patients with CLL and correlated with disease characteristics, prognostic factors, and survival. The mean TNF-α plasma concentration in the patients with CLL was significantly higher than in the healthy control population (16.4 versus 8.7 pg/mL; P &lt; .0001). Patients having an elevated TNF-α level had more advanced Rai and Binet stage disease, higher serum β2-microglobulin (β2M) levels, a greater percentage of cells expressing CD38, and lower hemoglobin and platelet levels. Patients having chromosomal abnormalities such as 11q deletion, trisomy 12, and chromosome 17 aberrations had a higher mean TNF-α level (27.5 pg/mL) than patients having a diploid karyotype or other miscellaneous cytogenetic abnormalities (14.2 pg/mL;P &lt; .001). The TNF-α level was a predictor of survival when the Cox proportional hazards model was used with TNF-α entered as a continuous variable (P = .0001). Also, patients having a TNF-α level above the mean value of 14 pg/mL had significantly shorter survival duration (P = .00001). The TNF-α level remained predictive of survival in Cox multivariate analysis independent of Rai staging and β2M, hemoglobin, prior therapy, white cell count, and platelet level (P = .005). We conclude that the TNF-α level serves as a prognostic factor in patients with CLL and that inhibition of TNF-α in these patients could have therapeutic importance.

In vitro effects of recombinant TNF-alpha binding protein (rTBP-1) on hematopoiesis of HIV-infected patients

Tumor necrosis factor-alpha (TNF-alpha) is believed to contribute to the hematopoietic failure often observed in patients with AIDS. Soluble TNF receptors (sTNFR) compete for TNF-alpha with cell surface receptors and thus may block its activity. The effect of the p55 sTNFR (recombinant TNF-binding protein-1 [rTBP-1]) on the clonogenic growth of hematopoietic progenitor cells from 27 HIV-infected patients was evaluated in comparison with 11 normal study subjects. Peripheral blood-derived, myelopoietic (i.e., granulomonocytic colony-forming cells [GM-CFC]) and erythropoietic (i.e, burst-forming unit, erythroid [BFU-E]) colonies were grown in 10-day semisolid cultures with increasing concentrations of rTBP-1. Significantly, dose-dependent increases occurred in GM-CFC from 17 of 21 AIDS patients and 12 of 21 in BFU-E at rTBP-1 concentrations of 1microg/ml to 25 microg/ml. In contrast, rTBP-1 failed to induce any appreciably increased colony formation in normal cell cultures. In 6 patients treated with highly active antiretroviral treatment (HAART), TBP-1 alone did not demonstrate the in vitro hematopoiesis-enhancing effect. This study may provide an initial step in development of therapeutic use of TBP as a TNF-alpha antagonist in HIV-infected patients who do not benefit sufficiently from antiretroviral treatment, and in other conditions in which increased levels of TNF-alpha may contribute to hematopoietic deficiencies.

Tumor necrosis factor-alpha and TNF-beta inhibit clonogenicity of mobilized human hematopoietic progenitors

We studied the effect of tumor necrosis factors (TNF-alpha and TNF-beta) on the clonogenicity of peripheral blood progenitor cells (PBPC) mobilized by granulocyte colony-stimulating factor (G-CSF). The cells were obtained by nine leukaphereses in patients with malignancies undergoing peripheral blood stem cell transplantation (PBSCT). Flow cytometry was performed to evaluate the number of CD34+ cells in peripheral blood and leukapheresis products. PBPC were grown in semisolid medium supplemented with human growth factors in the absence or presence of TNF at concentrations ranging from 0.1 to 10 ng/ml. Colonies were scored on day 14. TNF-alpha and TNF-beta suppressed colony formation in all cases studied. TNF-alpha inhibited the growth of colony-forming units-granulocyte-macrophage (CFU-GM) at 1 and 10 ng/ml and burst-forming units-erythroid (BFU-E) at 10 ng/ml (p < 0.05), and TNF-beta inhibited the growth of CFU-GM and BFU-E at 1 and 10 ng/ml (p < 0.05). Thus, G-CSF-mobilized hematopoietic PBPC are highly sensitive to both TNF-alpha and TNF-beta. This finding should be taken in account when PBPC are handled ex vivo.

The effects of feline retroviruses on cytokine expression

To identify potential roles of cytokines in retroviral pathogenesis, we used reverse transcription-quantitative competitive polymerase chain reaction (RT-qcPCR) assays to characterize mRNA levels of 19 different lymphokines, chemokines, monokines and hematopoietic growth factors in three feline cell lines productively infected with subgroup A feline leukemia virus (FeLV-A) or various feline immunodeficiency virus (FIV) strains. Infection of a CD8+, CD5- large granular lymphocyte (LGL) cell line with FeLV-A activated expression of interleukin-7 (IL-7), induced modest (4-fold) increases in granulocyte/macrophage colony-stimulating factor (GM-CSF) and leukemia inhibitory factor (LIF) transcripts, and decreased transforming growth factor-beta (TGF-beta) mRNA (4-fold). The LGL cells were not susceptible to infection by FIV. Infection of MYA-1 cells, a CD4+ T-lymphoblastoid cell line, with FeLV-A activated expression of macrophage inflammatory protein-1alpha (MIP-1alpha), increased transcript levels of GM-CSF (8-fold), macrophage CSF (M-CSF) (16-fold) and stem cell factor (SCF) (250-fold), and decreased (4-fold) expression of IL-10 and tumor necrosis factor-alpha (TNF-alpha). Productive infection with four different FIV molecular clones caused progressive MYA-1 cell death; however, the mRNA expression profiles were unchanged except for 2- to 4-fold increases in M-CSF and 16- to 500-fold increases in SCF. Thus, FIV-induced MYA-1 cytopathicity was not associated with dysregulation of pro-apoptotic or survival factor transcript levels. Lastly, productive infection of PNI cells, a marrow-derived fibroendothelial cell line, with FeLV-A or any of three FIV strains induced 4-fold higher levels of IL-12p40 transcripts and variably higher levels (4- to 64-fold) of GM-CSF. Two viral strains, the FIV-14 molecular clone and the clinical isolate FIV-5122, caused syncytia formation and unique activation of IL-1beta and stromal cell-derived factor-1 (SDF-1) expression, suggesting a potential role for those factors in viral spread and/or cytopathicity. In addition, infection with FIV-5122, but not the other FIV strains or FeLV-A, induced significant increases in mRNA levels of the hematopoietic inhibitors TNF-alpha and MIP-1alpha, along with increased concentrations of soluble proteins in culture supernatants. Consistent with this, supernatant from FIV-5122 infected PNI cells suppressed hematopoietic progenitor growth in colony assays, compared to supportive activities in supernatants from other infected or uninfected PNI cell cultures. Together, these data demonstrate that feline retroviruses alter cytokine mRNA levels in general and strain-specific patterns. These changes may result in specific alterations in cell function and contribute to retroviral pathogenesis. Our observations provide a basis for directed studies of candidate factors within the hematopoietic, thymic and lymphoid microenvironments.

The influence of recombinant human tumor necrosis factor alpha and its muteins used alone or in combination with 2-chlorodeoxyadenosine on normal and leukemic hematopoiesis in vitro

We investigated the influence of TNF alpha and its muteins III, V and VI on the colony growth of normal and CML CFU-GM cells as well as on CFU-L clonogenic blasts from AML patients in cultures in vitro. The muteins were constructed using a synthetic cDNA fragment substituting nucleotides coding for the N-terminal amino acids in the chain of native TNF alpha. We observed that TNF alpha and mutein VI inhibited the growth of colonies formed by both types of CFU-GM and CFU-L cells in a greater degree than muteins III and V. In addition, the percentage of colony growth inhibition after the use of mutein VI was the greatest. These observations were the basis for the evaluation of interaction between 2-CdA and TNF alpha and between 2-CdA and mutein VI. We have confirmed that 2-CdA used together with mutein VI acts synergistically on CFU-GM and CFU-L cells, whereas 2-CdA and TNF alpha show the additive effect.

Tumor Necrosis Factor Constellation Polymorphism and Clozapine-Induced Agranulocytosis in Two Different Ethnic Groups

Genes of the major histocompatibility complex (MHC) are associated with susceptibility to different immune and nonimmune mediated diseases. We had reported that the drug adverse reaction, clozapine-induced agranulocytosis (CA), is associated with different HLA types and HSP70 variants in Ashkenazi Jewish and non-Jewish patients, suggesting that a gene within the MHC region is associated with CA. This study was designed to find common genetic markers for this disorder in both ethnic groups. The tumor necrosis factor (TNF ) microsatellites d3 and b4 were found in higher frequencies in both Jewish and nonJewish patients: 51 of 66 (77%) and 48 of 66 (57%), respectively. Comparisons of these frequencies with those of controls, 28 of 66 (42%) and 18 of 66 (27%), were statistically significant (corrected P value = .001 for the d3 allele and .0005 for the b4 allele). On the other hand, the TNF microsatellite b5 was underrepresented in the group of patients, 9 of 66 (14%), when compared with the control subjects, 43 of 66 (65%) (corrected P value = .0005), probably related to protection from CA. Our results show a strong association of some genetic variants of the TNF loci with susceptibility to CA in two different ethnic groups suggesting involvement of TNF and/or associated gene(s) products in the pathogenesis of this hematologic-drug adverse reaction.