Thalidomide Induces Apoptosis in Human Monocytes by Using a Cytochrome c-Dependent Pathway

Apoptosis, Autophagy, NETosis, Necroptosis, and Pyroptosis Mediated Programmed Cell Death as Targets for Innovative Therapy in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that can lead to clinical manifestations of systemic diseases. Its leading features include chronic synovial inflammation and degeneration of the bones and joints. In the past decades, multiple susceptibilities for rheumatoid arthritis have been identified along with the development of a remarkable variety of drugs for its treatment; which include analgesics, glucocorticoids, nonsteroidal anti-inflammatory medications (NSAIDs), disease-modifying anti-rheumatic drugs (DMARDs), and biologic response modifiers (bDMARDs). Despite the existence of many clinical treatment options, the prognosis of some patients remains poor due to complex mechanism of the disease. Programmed cell death (PCD) has been extensively studied and ascertained to be one of the essential pathological mechanisms of RA. Its dysregulation in various associated cell types contributes to the development of RA. In this review, we summarize the role of apoptosis, cell death-associated neutrophil extracellular trap formation, necroptosis, pyroptosis, and autophagy in the pathophysiology of RA to provide a theoretical reference and insightful direction to the discovery and development of novel therapeutic targets for RA.

Thal protects against paraquat-induced lung injury through a microRNA-141/HDAC6/IκBα-NF-κB axis in rat and cell models

The protective functions of thalidomide in paraquat (PQ)-induced injury have been reported. But the mechanisms remain largely unknown. In this research, a PQ-treated rat model was established and further treated with thalidomide. Oedema and pathological changes, oxidative stress, inflammation, fibrosis and cell apoptosis in rat lungs were detected. A PQ-treated RLE-6TN cell model was constructed, and the viability and apoptosis rate of cells were measured. Differentially expressed microRNAs (miRNAs) after thalidomide administration were screened out. Binding relationship between miR-141 and histone deacetylase 6 (HDAC6) was validated. Altered expression of miR-141 and HDAC6 was introduced to identify their involvements in thalidomide-mediated events. Consequently, thalidomide administration alone exerted no damage to rat lungs; in addition it reduced PQ-induced oedema. The oxidative stress, inflammation and cell apoptosis in rat lungs were reduced by thalidomide. In RLE-6TN cells, thalidomide increased cell viability and decreased apoptosis. miR-141 was responsible for thalidomide-mediated protective events by targeting HDAC6. Overexpression of HDAC6 blocked the protection of thalidomide against PQ-induced injury via activating the IkBα-NF-κB signalling pathway. Collectively, this study evidenced that thalidomide protects lung tissues from PQ-induced injury through a miR-141/HDAC6/IkBα-NF-κB axis.

Neuroinflammation as a Factor of Neurodegenerative Disease: Thalidomide Analogs as Treatments

Neuroinflammation is initiated when glial cells, mainly microglia, are activated by threats to the neural environment, such as pathogen infiltration or neuronal injury. Although neuroinflammation serves to combat these threats and reinstate brain homeostasis, chronic inflammation can result in excessive cytokine production and cell death if the cause of inflammation remains. Overexpression of tumor necrosis factor-α (TNF-α), a proinflammatory cytokine with a central role in microglial activation, has been associated with neuronal excitotoxicity, synapse loss, and propagation of the inflammatory state. Thalidomide and its derivatives, termed immunomodulatory imide drugs (IMiDs), are a class of drugs that target the 3'-untranslated region (3'-UTR) of TNF-α mRNA, inhibiting TNF-α production. Due to their multi-potent effects, several IMiDs, including thalidomide, lenalidomide, and pomalidomide, have been repurposed as drug treatments for diseases such as multiple myeloma and psoriatic arthritis. Preclinical studies of currently marketed IMiDs, as well as novel IMiDs such as 3,6'-dithiothalidomide and adamantyl thalidomide derivatives, support the development of IMiDs as therapeutics for neurological disease. IMiDs have a competitive edge compared to similar anti-inflammatory drugs due to their blood-brain barrier permeability and high bioavailability, with the potential to alleviate symptoms of neurodegenerative disease and slow disease progression. In this review, we evaluate the role of neuroinflammation in neurodegenerative diseases, focusing specifically on the role of TNF-α in neuroinflammation, as well as appraise current research on the potential of IMiDs as treatments for neurological disorders.

Arsenic Trioxide and Thalidomide Combination Induces Autophagy Along with Apoptosis in Acute Myeloid Cell Lines

Objective

Autophagy and apoptosis play key roles in cancer survival and pathogenesis and are governed by specific genes which have a dual role in both cell death and survival. Arsenic trioxide (ATO) and thalidomide (THAL) are used for treatment of many types of hematologic malignancies. ATO prevents the proliferation of cells and induces apoptosis in some cancer cells. Moreover, THAL has immunomodulatory and antiangiogenic effects in malignant cells. The aim of present study was to examine the effects of ATO and THAL on U937 and KG-1 cells, and evaluation of mRNA expression level of VEGFs genes, PI3K genes and some of autophagy genes.

Materials and Methods

In this in vitro experimental study, U937 and KG-1 cells were treated by ATO (0.4-5 μM) and THAL (5-100 μM) for 24, 48 and 72 hours. Cell viability was measured by MTT assay. The apoptosis rate and cell cycle arrest were evaluated by flow cytometry (Annexin/PI) and cell cycle flow cytometry analysis, respectively. The effect of ATO/THAL on mRNAs expression was evaluated by real-time polymerase chain reaction (PCR).

Results

ATO/THAL combination enhanced cell apoptosis in a dose-dependent manner. Also, ATO/THAL induced SubG1/ G1 phase arrest. mRNA expression levels of VEGFC (contrary to other VEGFs isoform), PI3K, AKT, mTOR, MEK1, PTEN, IL6, LC3 and P62 genes were upregulated in acute myeloid leukemia (AML) cells following treatment with ATO/THAL.

Conclusion

Combined treatment with ATO and THAL can inhibit proliferation and invasion of AML cells by down-regulating ULK1 and BECLIN1 and up-regulating PTEN and IL6, and this effect was more marked than the effects of ATO and THAL alone.

Thalidomide potentiates etoposide-induced apoptosis in murine neuroblastoma through suppression of NF-κB activation

PURPOSE

Treatment for high-risk neuroblastoma is still challenging. The purpose of the present study was to determine whether thalidomide suppresses etoposide-induced NF-κB activation and thus potentiates apoptosis in murine neuroblastoma.

METHODS

A murine neuroblastoma cell line, C1300, and A/J mice were used in this study. We evaluated NF-κB activation after using etoposide with or without thalidomide by quantitative analysis of NF-κB by ELISA and by Western blot analysis of IκB phosphorylation in vitro and in vivo. Induction of apoptosis was evaluated by Western blot analysis of the apoptotic signals caspase-3, 8, and 9 in vitro and by TUNEL assays in vivo. We also evaluated the efficacy of the combination of etoposide and thalidomide by assessing tumor growth and mouse survival in vivo.

RESULTS

Etoposide activated NF-κB in C1300 cells. This activation was suppressed by thalidomide and IκB was re-upregulated. The apoptotic signals were enhanced by the combination of thalidomide and etoposide compared with etoposide alone in vitro, which was consistent with TUNEL assays. The combination of etoposide and thalidomide also slowed tumor growth and mouse survival.

CONCLUSION

Thalidomide potentiates etoposide-induced apoptosis in murine neuroblastoma by suppressing NF-κB.

Biological evaluation of both enantiomers of fluoro-thalidomide using human myeloma cell line H929 and others

Over the last few years, thalidomide has become one of the most important anti-tumour drugs for the treatment of relapsed-refractory multiple myeloma. However, besides its undesirable teratogenic side effect, its configurational instability critically limits any further therapeutic improvements of this drug. In 1999, we developed fluoro-thalidomide which is a bioisostere of thalidomide, but, in sharp contrast to the latter, it is configurationally stable and readily available in both enantiomeric forms. The biological activity of fluoro-thalidomide however, still remains virtually unstudied, with the exception that fluoro-thalidomide is not teratogenic. Herein, we report the first biological evaluation of fluoro-thalidomide in racemic and in both (R)- and (S)-enantiomerically pure forms against (in vitro) H929 cells of multiple myeloma (MM) using an annexin V assay. We demonstrate that all fluoro-thalidomides inhibited the growth of H929 MM cells without any in-vivo activation. Furthermore, we report that the enantiomeric forms of fluoro-thalidomide display different anti-tumour activities, with the (S)-enantiomer being noticeably more potent. The angiogenesis of fluoro-thalidomides is also investigated and compared to thalidomide. The data obtained in this study paves the way towards novel pharmaceutical research on fluoro-thalidomides.

Design and Synthesis of N-Arylphthalimides as Inhibitors of Glucocorticoid-Induced TNF Receptor-Related Protein, Proinflammatory Mediators, and Cytokines in Carrageenan-Induced Lung Inflammation

N-Arylphthalimides (1-10P) derived from thalidomide by insertion of hydrophobic groups were evaluated for anti-inflammatory activity, and (4-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)-N'-[(4-ethoxyphenyl)methylidene]benzohydrazide 6P was identified as a promising anti-inflammatory agent. Further testing confirmed that compared with the control, 6P treatment resulted in a considerable decrease in CD4(+), NF-κB p65(+), TNF-α(+), IL-6(+), GITR(+), and IL-17(+) cell populations and an increase in the Foxp3(+), CD4(+)Foxp3(+), and IκBα(+) populations in whole blood and pleural fluid of a mouse model of lung inflammation. Moreover, treatment with compound 6P decreased the proteins associated with inflammation including TNF-α, IL-6, IL-17, GITR, NF-κB, COX-2, STAT-3, and iNOS and increased the anti-inflammatory mediators such as IL-10 and IL-4. Further, histopathological examination confirmed the potent anti-inflammatory effects of compound 6P. Thus, the N-arylphthalimide derivative 6P acts as a potent anti-inflammatory agent in the carrageenan-induced lung inflammation model, suggesting that this compound may be useful for the treatment of inflammation in a clinical setting.

Cereblon binding molecules in multiple myeloma

Immunomodulation is an established treatment strategy in multiple myeloma with thalidomide and its derivatives lenalidomide and pomalidomide as its FDA approved representatives. Just recently the method of action of these cereblon binding molecules was deciphered and results from large phase 3 trials confirmed the backbone function of this drug family in various combination therapies. This review details the to-date knowledge concerning mechanism of IMiD action, clinical applications and plausible escape mechanisms in which cells may become resistant/refractory to cereblon binding molecule based treatment.

Thalidomide prolongs survival after experimental musculoskeletal injury, through an effect on mononuclear apoptosis

BACKGROUND

This study was conducted to investigate the effects of intravenous thalidomide administration in an experimental model of musculoskeletal trauma. We hypothesized that because thalidomide inhibits secretion of tumor necrosis factor alpha (TNF-α), survival of animals that received thalidomide would be significantly prolonged.

MATERIAL AND METHODS

After an open fracture of the right femur, 24 rabbits were randomly assigned to control and thalidomide groups. Intravenous therapy with thalidomide was started 30 min after fracture. Hemodynamic monitoring of all animals was performed for 4 h. Survival was recorded and bacterial growth in blood and organs was measured after animal death or sacrifice. Blood was sampled for TNF-α measurement and for isolation of peripheral blood mononuclear cells (PBMCs). Apoptosis of PBMCs was measured by flow cytometry.

RESULTS

Survival was significantly prolonged in the thalidomide group. Apoptosis of PBMCs was increased in the control group compared with the thalidomide group at 24 h. There were no differences in vital signs, blood and tissue cultures, and serum TNF-α concentration between the two groups.

CONCLUSIONS

Intravenous thalidomide prolonged survival in an experimental model of severe musculoskeletal injury in rabbits. Its mechanism of action did not involve TNF-α suppression but prevention of mononuclear apoptosis. In view of these promising results, further research is needed to clarify the immunomodulatory mechanism of action of thalidomide and its potential use for the management of severe trauma.

Mechanism of immunomodulatory drugs' action in the treatment of multiple myeloma

Although immunomodulatory drugs (IMiDs), such as thalidomide, lenalidomide, and pomalidomide, are widely used in the treatment of multiple myeloma (MM), the molecular mechanism of IMiDs' action is largely unknown. In this review, we will summarize recent advances in the application of IMiDs in MM cancer treatment as well as their effects on immunomodulatory activities, anti-angiogenic activities, intervention of cell surface adhesion molecules between myeloma cells and bone marrow stromal cells, anti-inflammatory activities, anti-proliferation, pro-apoptotic effects, cell cycle arrest, and inhibition of cell migration and metastasis. In addition, the potential IMiDs' target protein, IMiDs' target protein's functional role, and the potential molecular mechanisms of IMiDs resistance will be discussed. We wish, by presentation of our naive discussion, that this review article will facilitate further investigation in these fields.

Thalidomide inhibits adipogenesis of orbital fibroblasts in Graves' ophthalmopathy

The expansion of orbital adipose tissue is a main pathophysiology of Graves' ophthalmopathy (GO), which is an inflammatory autoimmune disease in the orbital region. The effects of immunosuppressive drugs on adipogenesis of orbital fibroblasts have not been determined. Thalidomide, as an immunosuppressive drug, has recently been used in the therapy of many autoimmune diseases. In this study, we analyzed the effects of thalidomide on adipogenesis and found that adipocyte differentiation from preadipocytes in the orbital region was enhanced, which was demonstrated by enhanced expression of peroxisome proliferator activated receptor γ (PPARγ), ap2, and thyroid-stimulating hormone receptor (TSHR). The expression of inflammatory cytokines tumor necrosis factor α (TNFα) and interleukin 6 (IL-6) was also increased in GO. Thalidomide dose-dependently inhibited adipogenesis of 3T3-L1 preadipocytes and orbital fibroblasts from GO patients. Along with the inhibited adipogenesis, the expression of TSHR, TNFα, and IL-6 was also down-regulated. We discovered that the mechanism for thalidomide inhibiting adipogenesis was the down-regulation of PPARγ, rather than C/EBPβ and C/EBPδ. We suggest that, besides its canonical anti-TNFα effect, thalidomide plays a role in inhibiting adipogenesis of orbital fibroblasts in GO patients.

Apoptosis modulation as a promising target for treatment of systemic sclerosis

Diffuse systemic sclerosis (SSc) is a fatal autoimmune disease characterized by an excessive ECM deposition inducing a loss of function of skin and internal organs. Apoptosis is a key mechanism involved in all the stages of the disease: vascular damage, immune dysfunction, and fibrosis. The purpose of this paper is to gather new findings in apoptosis related to SSc, to highlight relations between apoptosis and fibrosis, and to identify new therapeutic targets.

Induction of apoptosis in human promyelocytic leukemia HL60 cells by an extract from Erythrina suberosa stem bark

In this study, the apoptosis-inducing effect of an alcoholic extract from Erythrina suberosa stem bark (ESB) was investigated using human promyelocytic leukemia HL60 cells. Cell viability was estimated by MTT assay. We found that the ESB inhibited cell proliferation in a dose- and time-dependent manner. A series of well-documented morphological changes, such as cell shrinkage, condensation of nuclear chromatin, and nuclear fragmentation, were observed by fluorescence microscopy. The gold standard scanning electron micrographs showed apoptotic bodies and formation of blebs. Cell cycle analysis showed a significant increase in Sub G(0) population of cells above 50 μg/ml. ESB treatment resulted in a dose-dependent increase in annexin V positive cells. Increase in intracellular ROS production up to sixfold was detected in ESB-treated HL60 cells by DCFH-DA assay. Dissipation of mitochondrial membrane potential of intact cells accompanied by increase in cytosolic cytochrome c was observed, which was followed by activation of caspase-9 and -3 but not caspase-8. DNA fragmentation analysis revealed typical ladders as early as 18 h indicative of caspase-3 role in the apoptotic pathway. The overall results suggest that ESB induces mitochondria-mediated intrinsic apoptotic pathway in HL60 cells and might have therapeutic value against human leukemia.

Apoptosis-inducing activity of clofazimine in macrophages

Clofazimine is a riminophenazine compound which has been used for the treatment of leprosy since the 1960s. Although the drug is effective in the management of leprosy reactions because of its anti-inflammatory activity, the mechanism leading to the cessation of inflammation is not well understood. In the present study, it was shown that clofazimine exhibits apoptosis-inducing activity in macrophages. When human monocyte-derived macrophages were cultured in vitro in the presence of clofazimine, the cells exhibited a marked decrease in metabolic activity and showed shrinkage in cell size, indicating cell death. Nuclear condensation and fragmentation were also observed by Giemsa and Hoechst 33248 stains. The endonuclease inhibitor ZnCl(2) inhibited the clofazimine-induced cell death. Significant enhancement of caspase-3 activity was observed in clofazimine-treated macrophages and THP-1 cells. Collectively, these results suggest the apoptosis-inducing activity of clofazimine in macrophages, which may also be responsible for the antibacterial properties of clofazimine.

Cell death signaling and anticancer therapy

For a long time, it was commonly believed that efficient anticancer regimens would either trigger the apoptotic demise of tumor cells or induce a permanent arrest in the G₁ phase of the cell cycle, i.e., senescence. The recent discovery that necrosis can occur in a regulated fashion and the increasingly more precise characterization of the underlying molecular mechanisms have raised great interest, as non-apoptotic pathways might be instrumental to circumvent the resistance of cancer cells to conventional, pro-apoptotic therapeutic regimens. Moreover, it has been shown that some anticancer regimens engage lethal signaling cascades that can ignite multiple oncosuppressive mechanisms, including apoptosis, necrosis, and senescence. Among these signaling pathways is mitotic catastrophe, whose role as a bona fide cell death mechanism has recently been reconsidered. Thus, anticancer regimens get ever more sophisticated, and often distinct strategies are combined to maximize efficacy and minimize side effects. In this review, we will discuss the importance of apoptosis, necrosis, and mitotic catastrophe in the response of tumor cells to the most common clinically employed and experimental anticancer agents.

A novel panel of protein biomarkers for predicting response to thalidomide-based therapy in newly diagnosed multiple myeloma patients

Multiple myeloma (MM) is a heterogeneous group of disorders both genotypically and phenotypically. Response to thalidomide-based induction therapy in newly diagnosed patients varies significantly in published clinical trials. Proteomic analysis was performed on 39 newly diagnosed MM patients treated with a thalidomide-based regimen (22 responders; 17 non-responders) using immunodepletion, 2-D DIGE analysis and mass spectrometry. Zinc-α-2-glycoprotein (ZAG), vitamin D-binding protein (VDB), serum amyloid-A protein (SAA) and β-2-microglobulin (B2M) had statistically significant higher concentrations in non-responders compared to responders, while haptoglobin (Hp) had a lower concentration. ELISAs were used to validate the candidate protein biomarkers using unfractionated serum from 51 newly diagnosed MM patients (29 responders; 22 non-responders). Using logistic regression, the best possible area under the curve (AUC) was 0.96 using ZAG, VDB and SAA in combination. Leave-one-out-cross-validation (LOOCV) indicated an overall predictive accuracy of 84% with associated sensitivity and specificity values of 81.8 and 86.2%, respectively. Subsequently, 16 of 22 thalidomide-refractory patients successfully achieved complete response or very good partial response using second-line treatment suggesting that the biomarker profile is specific to thalidomide response rather than identifying patients with MM refractory to all therapies. Using a novel panel of predictive biomarkers, the feasibility of predicting response to thalidomide-based therapy in previously untreated MM has been demonstrated.

Tumor necrosis factor-alpha promotes survival in methotrexate-exposed macrophages by an NF-kappaB-dependent pathway

Introduction

Methotrexate (MTX) induces macrophage apoptosis in vitro, but there is not much evidence for increased synovial macrophage apoptosis in MTX-treated patients. Macrophage apoptosis is reported, however, during clinical response to anti-tumor necrosis factor-alpha (TNF-α) treatments. This implies that TNF-α promotes macrophage survival and suggests that TNF-α may protect against MTX-induced apoptosis. We, therefore, investigated this proposal and the macrophage signaling pathways underlying it.

Methods

Caspase-3 activity, annexin-V binding/7-aminoactinomycin D (7-AAD) exclusion and cell-cycle analysis were used to measure steps in apoptosis of primary murine macrophages and cells of the RAW_264.7 macrophage cell line that had been exposed to clinically-relevant concentrations of MTX and TNF-α.

Results

MTX induces apoptosis in primary murine macrophages at concentrations as low as 100 nM in vitro. TNF-α, which has a context-dependent ability to increase or to suppress apoptosis, efficiently suppresses MTX-induced macrophage apoptosis. This depends on NF-κB signaling, initiated through TNF Receptor Type 1 ligation. Macrophage colony stimulating factor, the primary macrophage survival and differentiation factor, does not activate NF-κB or protect macrophages from MTX-induced apoptosis. A weak NF-κB activator, Receptor Activator of NF-κB Ligand (RANKL) is likewise ineffective. Blocking NF-κB in TNF-α-exposed macrophages allowed pro-apoptotic actions of TNF-α to dominate, even in the absence of MTX. MTX itself does not promote apoptosis through interference with NF-κB signaling.

Conclusions

These findings provide another mechanism by which TNF-α sustains macrophage numbers in inflamed tissue and identify a further point of clinical complementarity between MTX and anti-TNF-α treatments for rheumatoid arthritis.

p62 (SQSTM1) and cyclic AMP phosphodiesterase-4A4 (PDE4A4) locate to a novel, reversible protein aggregate with links to autophagy and proteasome degradation pathways

Chronic challenge of cyclic AMP phosphodiesterase-4A4 (PDE4A4) with certain PDE4 selective inhibitors causes it to reversibly form intracellular aggregates that are not membrane-encapsulated. These aggregates are neither stress granules (SGs) nor processing bodies (PBs) as they contain neither PABP-1 nor Dcp1a, respectively. However, the PDE4 inhibitor rolipram decreases arsenite-induced SGs and increases the amount of PBs, while arsenite challenge ablates rolipram-induced PDE4A4 aggregates. PDE4A4 aggregates are neither autophagic vesicles (autophagosomes) nor aggresomes, although microtubule disruptors ablate PDE4A4 aggregate formation. PDE4A4 constitutively co-immunoprecipitates with p62 protein (sequestosome1, SQSTM1), which locates to both PDE4A4 aggregates and autophagosomes in cells constitutively challenged with rolipram. The mTor inhibitor, rapamycin, activates autophagy, prevents PDE4A4 from forming intracellular aggregates and triggers the loss of bound p62 from PDE4A4. siRNA-mediated knockdown of p62 attenuates PDE4A4 aggregate formation. The p62-binding protein, light chain 3 (LC3), is not found in PDE4A4 aggregates. Blockade of proteasome activity and activation of autophagy with MG132 both increases the level of ubiquitinated proteins found associated with PDE4A4 and inhibits PDE4A4 aggregate formation. Activation of autophagy with either thapsigargin or ionomycin inhibits PDE4A4 aggregate formation. Inhibition of autophagy with either wortmannin or LY294002 activates PDE4A4 aggregate formation. The protein kinase C inhibitors, RO 320432 and GO 6983, and the ERK inhibitors UO 126 and PD 98059 all activated PDE4A4 aggregate formation, whilst roscovitine, thalidomide and the tyrosine kinase inhibitors, genistein and AG17, all inhibited this process. We suggest that the fate of p62-containing protein aggregates need not necessarily be terminal, through delivery to autophagic vesicles and aggresomes. Instead, we propose a novel regulatory mechanism where a sub-population of p62-containing protein aggregates would form in a rapid, reversible manner so as to sequester specific cargo away from their normal, functionally important site(s) within the cell. Thus an appropriate conformational change in the target protein would confer reversible recruitment into a sub-population of p62-containing protein aggregates and so provide a regulatory function by removing these cargo proteins from their functionally important site(s) in a cell.

Thalidomide attenuates nitric oxide-driven angiogenesis by interacting with soluble guanylyl cyclase

BACKGROUND AND PURPOSE

Nitric oxide (NO) promotes angiogenesis by activating endothelial cells. Thalidomide arrests angiogenesis by interacting with the NO pathway, but its putative targets are not known. Here, we have attempted to identify these targets.

EXPERIMENTAL APPROACH

Cell-based angiogenesis assays (wound healing of monolayers and tube formation in ECV304, EAhy926 and bovine arterial endothelial cells), along with ex vivo and in vivo angiogenesis assays, were used to explore interactions between thalidomide and NO. We also carried out in silico homology modelling and docking studies to elucidate possible molecular interactions of thalidomide and soluble guanylyl cyclase (sGC).

KEY RESULTS

Thalidomide inhibited pro-angiogenic functions in endothelial cell cultures, whereas 8-bromo-cGMP, sildenafil (a phosphodiesterase inhibitor) or a NO donor [sodium nitroprusside (SNP)] increased these functions. The inhibitory effects of thalidomide were reversed by adding 8-bromo-cGMP or sildenafil, but not by SNP. Immunoassays showed a concentration-dependent decrease of cGMP in endothelial cells with thalidomide, without affecting the expression level of sGC protein. These results suggested that thalidomide inhibited the activity of sGC. Molecular modelling and docking experiments revealed that thalidomide could interact with the catalytic domain of sGC, which would explain the inhibitory effects of thalidomide on NO-dependent angiogenesis.

CONCLUSION AND IMPLICATIONS

Our results showed that thalidomide interacted with sGC, suppressing cGMP levels in endothelial cells, thus exerting its anti-angiogenic effects. These results could lead to the formulation of thalidomide-based drugs to curb angiogenesis by targeting sGC.

Thalidomide prevents formation of multinucleated giant cells (Langhans-type cells) from cultured monocytes: possible pharmaceutical applications for granulomatous disorders

Thalidomide is an effective drug for chronic inflammatory diseases, but the mechanism underlying its immunomodulatory action remains uncertain. Thalidomide has been reported to clinically improve chronic inflammatory granulomatous disorders. In such disorders, the granulomas consist of epithelioid cells, scattered lymphocytes and multinucleated giant cells (MNGC; Langhans-type cells). The present experimental approach permitted the reproduction of MNGC formation from peripheral blood monocytes and examination of thalidomides effect on it. MNGC can be effectively generated from monocytes cultured in the presence of interleukin-4 (IL-4) and macrophage colony-stimulating factor(M-CSF) for 14 days. Thalidomide can inhibit the formation of MNGC in a dose-dependent manner. MNGC formation was partly inhibited by the presence of neutralizing TNF-alpha antibody in the responses induced by IL-4 and M-CSF. Autocrinal TNF-alpha production and modulation of cadhelin expression to regulate cell adhesion might be involved in this inhibitory action of thalidomide. Our results support thalidomides clinical efficacy in the treatment of chronic granulomatous disorders (granulomatosis).

Drug-regulatable cancer cell death induced by BID under control of the tissue-specific, lung cancer-targeted TTS promoter system

Gene therapy and virotherapy are among the approaches currently being used to treat lung cancer. The success of cancer gene therapy depends on treatments where different types of tumors can be selectively targeted and destroyed without affecting normal cells and tissue. Previously, we described a promoter system (TTS) that we designed that is specifically targeted to lung cancer cells but which does not affect other types of cells including stem cells. In our study, we have enhanced the utility of the TTS system by inserting the pro-apoptotic gene BH3 domain interacting death agonist (Bid) into the TTS promoter system (TTS/Bid) to create a drug regulatable lung cancer-specific gene therapy. A recombinant adenoviral vector was used to introduce TTS/Bid (Ad-TTS/Bid) into lung cancer cells. BID expression and apoptosis occurred in A549 pulmonary adenocarcinoma cells but little Bid expression or apoptosis occurred in MCF7 breast cancer cells or in normal human lung fibroblasts. The use of cisplatin enhanced the processing of full length BID to t-BID which significantly increased lung cancer-specific cell death. In in vivo experiments, intraperitonal injection of cisplatin enhanced the antitumor effects of the vector in a lung cancer xeno-graft mouse model. Moreover, dexamethasone effectively suppressed exogenous BID expression and the antitumor effect of Ad-TTS/Bid both in vitro and in vivo. Here, we describe the efficacy of the use of cisplatin and dexamethasone with the anti lung cancer promoter system (Ad-TTS/Bid) for a safe and effective gene therapy against advanced lung cancer.

CC-10004 but not thalidomide or lenalidomide inhibits lamina propria mononuclear cell TNF-α and MMP-3 production in patients with inflammatory bowel disease

BACKGROUND

Thalidomide, one of whose activities is to inhibit Tumour Necrosis Factor (TNF)-α production, has been reported to be an effective treatment for refractory inflammatory bowel disease (IBD). TNF-α driven production of matrix metalloproteinase (MMP)-3 by gut lamina propria mononuclear cells (LPMCs) is a major pathway of tissue injury in IBD; however the effect of thalidomide and newer more potent immunomodulatory derivatives on this pathway has not been studied.

AIM

To investigate the effect of thalidomide, CC-4047 (pomalidomide), CC-5013 (lenalidomide), and CC-10004 (apremilast) on gut LPMC TNFα and MMP-3 production in patients with IBD.

METHODS

Gut LPMCs and myofibroblasts were isolated from patients with IBD, and cultured with thalidomide, CC-4047, CC-5013, and CC-10004. MMP-3 and TIMP-1 levels were determined by western blotting and real-time PCR, and TNF-α levels by ELISA.

RESULTS

CC-10004 significantly reduced both TNF-α production and MMP-3 production by cultured LPMCs. Thalidomide and CC-4047 and CC-5013 had no significant effect on the production of TNF-α or MMP-3 by LPMCs.

CONCLUSION

These results provides a mechanistic rationale for both the failure of lenalidomide (CC-5013) in a recent randomised controlled trial in Crohn's disease, and for the evaluation of CC-10004 as a novel oral therapy in the treatment of CD and UC.

Thalidomide and thalidomide analogues for induction of remission in Crohn's disease

BACKGROUND

Crohn's disease is a chronic relapsing condition of the alimentary tract with a high morbidity secondary to bowel inflammation. High levels of tumour necrosis factor-alpha (TNF-alpha) have been associated with the development of intestinal inflammation in Crohn's disease.Thalidomide, has been demonstrated to have anti TNF-alpha properties in experimental and clinical studies.

OBJECTIVES

To evaluate the efficacy and safety of thalidomide and its analogue lenalidomide for induction of remission in Crohn's disease.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL) Issue 3, 2008, PUBMED (1966 to August 2008), EMBASE (1984 to August 2008) and the Cochrane IBD/FBD Specialised Trial Register were searched. Manufacturers of thalidomide and leaders in the field were also contacted to identify any unpublished trials. Study references were also searched for additional trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared thalidomide or lenalidomide against placebo or any other intervention for induction of remission in Crohn's disease were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of methodological quality of included studies were independently performed by two authors. The main outcome measure was clinical remission. Odds ratios and 95% confidence intervals were calculated for dichotomous outcomes.

MAIN RESULTS

No published RCTs on thalidomide for induction of remission in Crohn's disease were found. One RCT in paediatric patients is in progress. One RCT using lenalidomide (n = 89) met the inclusion criteria and was included in the review. Three parallel groups of patients on 25 mg of lenalidomide daily (n = 23) , 5 mg of lenalidomide daily (n = 33) or placebo (n = 28) were studied. The clinical remission rate in both treatment groups was not significantly different from that in the placebo group; 25 mg lenalidomide versus placebo (OR 0.29; 95% CI 0.05 to 1.54), 5 mg lenalidomide versus placebo (OR 1.30; 95% CI 0.42 to 4.05). There were no statistically significant differences in clinical response.

AUTHORS' CONCLUSIONS

The results of one well designed study using lenalidomide did not show any statistically significant benefit over placebo. The use of thalidomide or lenalidomide for induction of remission in Crohn's disease is not recommended until data from a definitive study are available.

Targeted therapies in multiple myeloma

Increasing knowledge of the biology of multiple myeloma led the way for the development of novel drugs that have changed the management of the disease. New treatments target not only to the malignant plasma cell but also target the interactions of myeloma cells with their microenvironment. Several preclinical studies have identified potential targets and drugs are developed that act on pathways crucial for myeloma cell survival, proliferation, migration and drug resistance. The identification of active agents in the laboratory is followed by rationally designed clinical studies that validate these drugs, either as single agents or in combinations with other active drugs. These novel agents may be either small molecules or monoclonal antibodies targeting receptors, kinase activity of receptors or key molecules within critical pathways, intracellular maintenance mechanisms and immune modulation.

Thalidomide: mechanisms of action

The classification of thalidomide as an orphan drug with anti-inflammatory actions has led to its off-label use in conditions refractory to other medications. Although the observed clinical effects of thalidomide suggest it to have immunomodulatory capabilities, the mechanism of action is unclear. Here we review both the positive and negative studies of thalidomide at the bench in order to improve our understanding of the possible mechanisms of this drug in treating a variety of diseases at the bedside. Studies on the effects of thalidomide on the innate and adaptive immune system as well as tumorigenesis and angiogenesis are discussed.

Treatment of plasma cell dyscrasias with lenalidomide

Lenalidomide is an immunomodulatory drug, structurally related to thalidomide, with pleiotropic activity including antiangiogenic and antineoplastic properties. It is the product of advances in our understanding of the biology of myeloma cells, their interactions with the microenvironment and of the underlying molecular pathways. In preclinical and clinical studies, lenalidomide was more potent and less toxic than thalidomide. Subsequent phase II and III studies confirmed the activity of lenalidomide either as a single agent or in combination with dexamethasone in relapsed or refractory myeloma patients, whereas combinations with chemotherapy induce high response rates and durable remissions. Lenalidomide has been used successfully as an upfront treatment either with high or low dose dexamethasone or with melphalan and prednisone, resulting in high overall response and complete response rates and excellent 1-year survival. Lenalidomide causes less neuropathy than thalidomide; however, the risk of thromboembolism is high, especially in patients treated with lenalidomide and steroids. In this review, we summarize the mechanisms of action, toxicity and clinical activity, and the current role of lenalidomide in patients with multiple myeloma or other related plasma cell disorders.

Thalidomide induces limb anomalies by PTEN stabilization, Akt suppression, and stimulation of caspase-dependent cell death

Thalidomide, a drug used for the treatment of multiple myeloma and inflammatory diseases, is also a teratogen that causes birth defects, such as limb truncations and microphthalmia, in humans. Thalidomide-induced limb truncations result from increased cell death during embryonic limb development and consequential disturbance of limb outgrowth. Here we demonstrate in primary human embryonic cells and in the chicken embryo that thalidomide-induced signaling through bone morphogenetic proteins (Bmps) protects active PTEN from proteasomal degradation, resulting in suppression of Akt signaling. As a consequence, caspase-dependent cell death is stimulated by the intrinsic and Fas death receptor apoptotic pathway. Most importantly, thalidomide-induced limb deformities and microphthalmia in chicken embryos could be rescued by a pharmacological PTEN inhibitor as well as by insulin, a stimulant of Akt signaling. We therefore conclude that perturbation of PTEN/Akt signaling and stimulation of caspase activity is central to the teratogenic effects of thalidomide.

Thalidomide induces limb anomalies by PTEN stabilization, Akt suppression, and stimulation of caspase-dependent cell death

Thalidomide, a drug used for the treatment of multiple myeloma and inflammatory diseases, is also a teratogen that causes birth defects, such as limb truncations and microphthalmia, in humans. Thalidomide-induced limb truncations result from increased cell death during embryonic limb development and consequential disturbance of limb outgrowth. Here we demonstrate in primary human embryonic cells and in the chicken embryo that thalidomide-induced signaling through bone morphogenetic proteins (Bmps) protects active PTEN from proteasomal degradation, resulting in suppression of Akt signaling. As a consequence, caspase-dependent cell death is stimulated by the intrinsic and Fas death receptor apoptotic pathway. Most importantly, thalidomide-induced limb deformities and microphthalmia in chicken embryos could be rescued by a pharmacological PTEN inhibitor as well as by insulin, a stimulant of Akt signaling. We therefore conclude that perturbation of PTEN/Akt signaling and stimulation of caspase activity is central to the teratogenic effects of thalidomide.

Apoptosis as a therapeutic tool in IBD?

Defective apoptosis of mucosal cell populations seems to be a relevant pathogenetic mechanism in inflammatory bowel disease (IBD). It has been suggested that the induction of apoptosis in various effector cells may be a relevant therapeutic mechanism in IBD. Indeed, it was shown that different drugs used for treatment of IBD have the capacity to induce apoptosis in T cells or monocytes in vitro and in vivo. However, it remains unclear whether these observations are related to clinical efficacy of these agents. TNF-alpha is one of the most relevant proinflammatory mediators in IBD and anti-TNF treatment has been shown to be of particular benefit for patients with IBD. It could subsequently be shown that various anti-TNF-alpha agents, such as infliximab and adalimumab, can induce apoptosis in activated monocytes and lymphocytes in vitro and in vivo. This mechanism requires reverse signaling via transmembranous TNF, thereby eliciting a signal transduction cascade that results in programmed cell death. Although other mechanisms might also contribute to the clinical effect of anti-TNF-alpha, current data suggest that apoptosis is a relevant mechanism that is associated with clinical efficacy of anti-TNF agents. Induction of apoptosis in activated monocytes or T cells may be regarded as therapeutic tool not only for anti-TNF agents, but also for other drugs used in IBD. Future strategies should focus on identification of mechanisms that prevent apoptosis in the mucosa of patients with IBD and in targeting apoptotic pathways as a therapeutic strategy in IBD.

Recent understanding of IBD pathogenesis: implications for future therapies

The inflammatory bowel diseases (IBD) are comprised of two major phenotypes, Crohn's disease (CD) and ulcerative colitis (UC). Research over the last couple of years has led to great advances in understanding the inflammatory bowel diseases and their underlying pathophysiologic mechanisms. From the current understanding, it is likely that chronic inflammation in IBD is due to aggressive cellular immune responses to a subset of luminal bacteria. Susceptibility to disease is thereby determined by genes encoding immune responses which are triggered by environmental stimuli. Based on extensive research over the last decade, there are several new and novel pathways and specific targets on which to focus new therapeutics. The following review summarizes the current view on the four basic tenets of the pathophysiological basis of IBD and its implications for therapies of IBD: genetics, immune dysregulation, barrier dysfunction and the role of the microbial flora.

Guanosine 5'-triphosphate induces differentiation-dependent apoptosis in human leukemia U937 and KG1 cells

AIM

The differentiation capability of guanosine 5'-triphosphate (GTP) was studied using U937 and KG1 cells.

METHODS

Cell cycle was analyzed by PI staining using flow cytometry. Apoptosis was measured by Annexin-V-FITC/PI double staining using flow cytometry. Differentiation was observed by morphological criteria, Wright-Giemsa staining and expression of cell surface markers CD11b and CD14.

RESULTS

Variable GTP concentrations (25-200 micromol/L) at short treatment times (up to 24 h) showed significant anti-proliferative activities among both cell types. However, longer treatment times (up to 72 h) were required to trigger apoptosis. Cell-cycle analyses of the GTP-treated cells indicated an increase in S-phase population by 48 h followed by the appearance of a sub-G(1) peak after 72 h of treatment. The effects of GTP on U937 and KG1 cells were accompanied with differentiation toward monocyte/macrophage lineage. This was evidenced by a sharp increase in the extent of CD11b and CD14 expression after 24 h of exposure to GTP. The viability of both cell types did not significantly change during the first 24 h. However, at longer treatment times (72-96 h), dramatic decreases in both the extent of CD14 expression and the cell viabilities were observed. Simultaneous measurement of apoptosis and CD14 expression in GTP-treated U937 cells indicated that cells with lower CD14 content underwent more apoptosis.

CONCLUSION

These finding may pave the way for further pharmaceutical evaluation of GTP as a suitable differentiating agent for acute myeloblastic leukemia (AML) therapy.

Dexamethasone -induced apoptosis of human monocytes exposed to immune complexes. Intervention of CD95- and XIAP-dependent pathways

Monocytes and macrophages play a key role in the initiation and persistence of inflammatory reactions. The possibility to interfere with the survival of these cells, once recruited and activated at sites of inflammation, is an attractive therapeutic option. Although resting monocytes are susceptible to pharmacologically induced apoptosis, no data are available about the possibility to modulate the survival of activated monocytes. The present work was planned to investigate if dexamethasone is able to promote apoptosis of human monocytes activated by immune complexes. When monocytes were cultured with immune complexes, a dose-dependent inhibition of apoptosis was observed. Dexamethasone stimulated apoptosis of resting and activated monocytes in a dose-dependent manner. Both the immune complex inhibitory activity and dexamethasone stimulatory properties depend on NF-kappaB/XIAP and Ras/MEK/ERK/CD95 pathways. In fact, the exposure of monocytes to immune complexes increased NF-kB activation and XIAP expression, which in turn were inhibited by dexamethasone. On the other hand, immune complex-stimulated monocytes displayed a reduced expression of CD95, which is prevented by dexamethasone, as well as by MEK inhibitor U0126. Furthermore, anti-CD95 ZB4 mAb prevented dexamethasone-induced apoptosis in immune complex stimulated monocytes. Similarly, ZB4 inhibited dexamethasone-mediated augmentation of caspase 3 activity. The present findings suggest that Fc triggering by insoluble immune complexes result in the activation of two intracellular pathways crucial for the survival of monocytes: 1. Ras/MEK/ERK pathway responsible for the down-regulation of CD95 expression; 2. NF-kappaB pathway governing the expression of XIAP. Both the pathways are susceptible to inhibition by monocyte treatment with pharmacologic concentrations of dexamethasone.

Thalidomide and angiostatin inhibit tumor growth in a murine xenograft model of human cervical cancer

OBJECTIVE

To determine the impact of thalidomide and angiostatin on tumor growth, angiogenesis, and apoptosis in a xenograft model of cervical cancer.

METHODS

Human umbilical endothelial cells were treated with angiostatin or thalidomide and bFGF-induced proliferation was assessed with the MTT assay. Human cervical cancer cells (CaSki and SiHa) were injected into the flanks of nude mice. After tumors developed, mice were treated with angiostatin 20 mg/kg/day or thalidomide 200 mg/kg/day for 30 days. Fractional tumor growth was determined and immunohistochemical analysis of tumors was used to determine degree of angiogenesis. TUNEL assay was used to assess apoptosis.

RESULTS

Angiostatin inhibited endothelial cell proliferation by 50-60%. Thalidomide had no direct effect on endothelial cells. Angiostatin and thalidomide both inhibited tumor growth by about 55%. We found no additive or synergistic effect when the two agents were combined. Both agents inhibited angiogenesis and induced apoptosis when compared to tumors from control animals.

CONCLUSIONS

Angiostatin and thalidomide inhibit tumor growth, angiogenesis, and induce apoptosis in this xenograft model of cervical cancer.

Thalidomide enhances the anti-tumor activity of standard chemotherapy in a human melanoma xenotransplatation model

It has been demonstrated that thalidomide's anti-angiogenic properties result in clear anti-tumor activity in a number of human malignancies. We studied thalidomide in a human melanoma severe combined immunodeficiency mouse xenotransplantation model. Thalidomide as a single agent showed a significant tumor reduction of 46% compared with the control group. Thalidomide combined with dacarbazine treatment markedly enhanced the anti-tumor effect of chemotherapy and showed a significant tumor reduction relative to the dacarbazine-only group (61%) and even more tumor reduction (74%) compared with the control group. We also measured clearly reduced levels of tumor necrosis factor-alpha in the thalidomide-treated group. A significantly lower microvessel density was encountered in the thalidomide treatment groups (thalidomide alone or combined with DTIC), underscoring the anti-angiogenic effect of thalidomide as a single agent as well as in combination with chemotherapy in this model. In line with these results, we observed a nearly 3-fold increase of apoptosis for the combination of thalidomide and DTIC compared with the rate of apoptotic cells in DTIC-only-treated melanoma xenotransplants. These data underline the rationale for combining dacarbazine--a cytotoxic agent--and thalidomide--an anti-angiogenic cytostatic agent--as a promising strategy for the treatment of melanoma.

[TNF-alpha inhibitors in inflammatory bowel disease]

Inflammatory bowel disease (IBD) is a chronic immunoinflammatory response to an stimulus that activates a chain of cellular mediators causing intestinal damage. One of the most well recognized proinflammatory mediators involved in the pathogenesis of IBD is tumor necrosis factor alpha (TNFalpha). The treatment of IBD has advanced in parallel to the improvement of the knowledge of its physiopathology, leading to the development of biological therapies. An example of this kind of treatment is the use of substances that antagonize TNFalpha, such as monoclonal antibodies infliximab, adalimumab, natalizumab, etanercept or onercept, with infliximab being the unique approved for use in IBD. Several studies have demonstrated that inhibition of TNFalpha is useful in the treatment of Crohn's disease (CD). In CD, infliximab induces the remission of relapses which are refractory to the conventional treatment, prevents more relapses and induces a closure of enterocutaneous and perianal fistula that do not respond to first line treatment. However, infliximab is not useful in ulcerative colitis. Infliximab treatment has some drawbacks, such as the development of anti-infliximab antibodies, which cause a loss of efficacy of the treatment and hypersensitivity reactions. Other reported adverse effects of infliximab are the development of autoimmunity, such as that related with antinuclear or anti-DNA antibodies, or the reactivation of infections such as tuberculosis. In fact, a screening for tuberculosis is necessary before administration of infliximab. To reduce the adverse effects due to infliximab immunogenicity, several trials with humanized or completely human agents, such as adalimumab or onercept, are under way. Until the precise stimulus that triggers IBD is identified, biological therapies have a great future and the selective antagonism of TNFalpha is already a reality.

NF-κB protects Behçet's disease T cells against CD95-induced apoptosis up-regulating antiapoptotic proteins

OBJECTIVE

To determine whether prolongation of the inflammatory reaction in patients with Behçet's disease (BD) is related to apoptosis resistance and is associated with the up-regulation of antiapoptotic factors.

METHODS

The percentage of cell death was evaluated by flow cytometry in peripheral blood mononuclear cells from 35 patients with BD and 30 healthy volunteers. The expression levels of antiapoptotic factors and NF-kappaB regulatory proteins were measured using Western blotting and immunohistochemical analyses. To down-regulate NF-kappaB nuclear translocation, BD T lymphocytes were exposed in vitro to thalidomide and subjected to transfection with NF-kappaB small interfering RNA.

RESULTS

Although CD95 is highly expressed in BD T cells, the absence of sensitivity to CD95-induced apoptosis observed may be attributable to the inhibitory action of antiapoptotic genes. Immunoblot analysis for major antiapoptotic proteins showed considerable up-regulation of the short form of cellular FLIP (cFLIP) and Bcl-x(L) in BD activated T cells, while levels of Bcl-2, caspase 3, and caspase 8 in activated T cells from patients with BD were comparable with those in activated T cells from normal donors. Moreover, expression of IKK and IkappaB was up-regulated, whereas NF-kappaB translocated to the nucleus in BD T cells, suggesting that NF-kappaB activation may modulate the expression of antiapoptotic genes. Interestingly, thalidomide and NF-kappaB small interfering RNA down-regulated cFLIP and Bcl-x(L) expression levels and sensitized BD activated T cells to CD95-induced apoptosis.

CONCLUSION

Taken together, these results indicate that NF-kappaB contributes to the regulation of the apoptosis-related factors and death receptors leading to apoptosis resistance in BD T cell subsets. Our results suggest that NF-kappaB plays a crucial role in the pathogenesis of BD, and that its pharmacologic control could represent a key strategy in modulating specific immune-mediated disease.