Thalidomide revisited: pharmacology and clinical applications

Thalidomide is attracting new interest. Since the discovery of its remarkable efficacy in erythema nodosum leprosum, the drug has been used successfully in a variety of dermatologic and other diseases whose apparent common thread is immune dysregulation. Meanwhile, immunomodulatory and anti-inflammatory activities of thalidomide, particularly its inhibition of tumour necrosis factor alpha (TNF-alpha), have been identified and elucidated. The drug has also been found to inhibit angiogenesis. Recent clinical trials have shown thalidomide effective in graft-versus-host disease, Beh?et's syndrome and aphthous ulcers and wasting associated with HIV infection. Provocative findings in other diseases, including primary HIV infection, HIV-associated diarrhoea, inflammatory bowel disease, cancer and sepsis, have suggested additional clinical applications. Use of thalidomide in women capable of childbearing is controversial. However, guidelines have emerged for prevention of teratogenicity and peripheral neuropathy, the drug's other major adverse effect. With appropriate safeguards, thalidomide may hold benefit for patients with a broad variety of disorders in which existing treatments are inadequate. Its current use may represent only a small part of its therapeutic potential.     

Thalidomide revisited: pharmacology and clinical applications

Thalidomide is attracting new interest. Since the discovery of its remarkable efficacy in erythema nodosum leprosum, the drug has been used successfully in a variety of dermatologic and other diseases whose apparent common thread is immune dysregulation. Meanwhile, immunomodulatory and anti-inflammatory activities of thalidomide, particularly its inhibition of tumour necrosis factor alpha (TNF-a), have been identified and elucidated. The drug has also been found to inhibit angiogenesis. Recent clinical trials have shown thalidomide effective in graft-versus-host disease, Behçet's syndrome and aphthous ulcers and wasting associated with HIV infection. Provocative findings in other diseases, including primary HIV infection, HIV-associated diarrhoea, inflammatory bowel disease, cancer and sepsis, have suggested additional clinical applications. Use of thalidomide in women capable of childbearing is controversial. However, guidelines have emerged for prevention of teratogenicity and peripheral neuropathy, the drug's other major adverse effect. With appropriate safeguards, thalidomide may hold benefit for patients with a broad variety of disorders in which existing treatments are inadequate. Its current use may represent only a small part of its therapeutic potential.     

A bis-malonic acid fullerene derivative significantly suppressed IL-33-induced IL-6 expression by inhibiting NF-κB activation

IL-33 functions as a ligand for ST2L, which is mainly expressed in immune cells, including mast cells. IL-33 is a potent inducer of pro-inflammatory cytokines, such as IL-6, and has been implicated in the pathogenesis of allergic inflammatory diseases. Therefore, IL-33 has recently been attracting attention as a new target for the treatment of inflammatory diseases. In the present study, we demonstrated that a water-soluble bis-malonic acid fullerene derivative (C₆₀-dicyclopropane-1,1,1′,1′-tetracarboxylic acid) markedly diminished the IL-33-induced expression of IL-6 in bone marrow-derived mast cells (BMMC). The bis-malonic acid fullerene derivative suppressed the canonical signaling steps required for NF-κB activation such as the degradation of IκBα and nuclear translocation of NF-κB by directly inhibiting the IL-33-induced IKK activation. Although p38 and JNK also contributed to IL-33-induced expression of IL-6, the bis-malonic acid fullerene derivative did not affect their activation. Furthermore, the bis-malonic acid fullerene derivative had no effect on the NF-κB activation pathway induced by TNFα and IL-1. These results suggest that the bis-malonic fullerene derivative has potential as a specific drug for the treatment of IL-33-induced inflammatory diseases by specifically inhibiting the NF-κB activation pathway.     

Recent advances in analytical determination of thalidomide and its metabolites

Thalidomide, a racemate, is coming into clinical use as immuno-modulating and anti-inflammatory drug. Thalidomide was approved by the FDA in July 1998 for the treatment of erythema nodusum leprosum associated with leprosy. Recently, thalidomide is proving to be a promising drug in the treatment of a number of cancers and inflammatory diseases, such as multiple myeloma, inflammatory bowel disease (Crohn's disease), HIV and cancer associated cachexia. These effects may chiefly be exerted by S-thalidomide, but the enantiomers are inter-converted in vivo. Thalidomide is given orally, although parenteral administration would be desirable in some clinical situations. Thalidomide has been determined in formulations and, principally in biological fluids by a variety of methods such as high-performance liquid chromatography with ultraviolet detection and liquid chromatography coupled with tandem mass spectrometry. The overview includes the most relevant analytical methodologies used in its determination.     

Potential novel uses of thalidomide: focus on palliative care

Thalidomide, after being banned from the market in the early 1960s because of the worldwide teratogenesis disaster, is currently being rediscovered because of its multiple therapeutic effects in various serious diseases and symptoms. Original studies examined the anxiolytic, mild hypnotic, anti-emetic and adjuvant analgesic properties of this drug. Subsequently, thalidomide was found to be highly effective in managing the cutaneous manifestations of leprosy (erythema nodosum leprosum) and even to be superior to aspirin (acetylsalicylic acid) in controlling leprosy-associated fever. Recent research shows promising results with thalidomide in patients with progressive bodyweight loss related to advanced cancer and HIV infection. Thalidomide therapy of diseases such as tuberculosis, sarcoidosis, aphthous ulcers in HIV syndrome and Behcet's disease, rheumatoid arthritis, multiple myeloma, graft-versus-host disease, pyoderma gangrenosum, inflammatory bowel disease, Sj?gren's syndrome, lupus erythematosus and a variety of solid tumours is currently being explored. Furthermore, in preliminary studies, thalidomide has been found to be effective in several syndromes related to advanced cancer, such as the cancer cachexia syndrome, chronic nausea, insomnia, profuse sweating and pain. Whether thalidomide has a therapeutic effect on neoplastic fever has yet to be elucidated. These intriguing features make the use of the drug potentially attractive for palliative care. In addition, by a distinct mechanism of action compared with most other drugs, thalidomide offers the possibility of combined treatment with other agents with non-overlapping toxicities. The mechanism of action of thalidomide is probably based on the suppression of tumour necrosis factor-alpha and the modulation of interleukins. However, it is not possible to identify a single dominant mechanism, since the action of cytokines and the effect of thalidomide appear to be complex. This review article discusses the original uses and teratogenic effects of thalidomide within its historical context and, linking recent research at the molecular level with clinical findings, aims to provide the reader with insight into the current understanding of its biological actions, toxicities and potential benefits.     

Inhibitory effect of the antidepressant imipramine on NF-κB-dependent CXCL1 expression in TNFα-exposed astrocytes

Neuroinflammation is associated with the pathophysiology of various neurodegenerative diseases. Emerging evidence indicates that imipramine, a tricyclic antidepressant commonly used in depressive disorders, exhibits neuroprotective activity partly through anti-inflammatory effects. However, the molecular mechanisms underlying imipramine-mediated anti-inflammatory response are poorly understood. In this study, rat primary cultured astrocytes were used to elucidate the effect of the imipramine on TNFα-induced inflammatory responses. The results clearly demonstrated that imipramine reduced TNFα-induced CXCL1 expression through suppression of NF-κB-dependent CXCL1 promoter activity in primary astrocytes. In addition, we found that imipramine suppressed TNFα-induced phosphorylation of inhibitor of κBα (IκBα) and p65/RelA nuclear factor-κB (NF-κB), as well as the nuclear translocation of p65/RelA in primary cultured astrocytes. Chemotaxis assay demonstrated that astrocyte-derived CXCL1 contributed to migration of BV2 microglial cells toward astrocytes. This response was significantly blocked by treatment of astrocytes with imipramine or NF-κB inhibitor BAY11-7082. This study indicates that the antidepressant imipramine inhibits TNFα-induced CXCL1 expression via down-regulation of NF-κB signaling pathway in astrocytes and suggests that imipramine has a potential as an anti-inflammatory drug.     

Comparative molecular field analysis and comparative molecular similarity indices analysis of thalidomide analogues as angiogenesis inhibitors

Thalidomide, 2-(2,6-dioxo-3-piperidinyl)-1H-isoindole-1,3(2H)-dione, has been shown to inhibit angiogenesis, the formation of new blood vessels from existing vasculature. As a result, there is renewed interest in this drug as a potential therapy for solid tumors. Thalidomide forms a number of metabolites and has been shown to require metabolic activation for antiangiogenic activity. A series of 39 compounds, based upon the structure of some of these metabolites, was synthesized and tested for their ability to inhibit microvessel growth in the rat aortic ring assay. The results of this testing have been used as the basis for a three-dimensional quantitative structure-activity relationship (3D-QSAR) study, utilizing comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) procedures. The best resulting CoMFA and CoMSIA models have conventional r(2) values of 0.924 and 0.996, respectively. The cross-validated q(2) values are 0.666 and 0.635, respectively. These models offer insight into the structural requirements for activity of thalidomide analogues as angiogenesis inhibitors, since there is only speculative knowledge of the target. Additionally, it appears as though there is more than one active site or mechanism of action.     

Thalidomide in the treatment of cancer

Thalidomide caused severe malformations in babies born to mothers taking the drug for morning sickness in the late 1950s and early 1960s. It is now known that these teratogenic effects are due to potent anti-angiogenic and immunomodulatory actions. These properties have lead to the testing of thalidomide in a number of infective, inflammatory and malignant conditions. Promising activity has been reported in myeloma, AIDS-related Kaposi's sarcoma, renal cell carcinoma and glioblastoma multiforme. A review is presented of the history of thalidomide and its recent development with an emphasis on applications in malignant disease.     

Thalidomide: chemistry, therapeutic potential and oxidative stress induced teratogenicity

Thalidomide and its one analogue, lenalidomide (CC5103 or revlimid) are recently approved for the treatment of multiple myeloma. Multiple myeloma is characterized by an overproduction of malignant plasma cells in the bone marrow. The journey of thalidomide was started in 1956 when it was marketed as a non-barbiturate sedative agent. It was considered as a "wonder drug" that provided safe and sound sleep and hence, used to cure morning sickness in pregnant women. Later, in 1961, it was withdrawn from the world market due to its serious side effects, i.e., teratogenic activity. However, the recent decade has witnessed a true renaissance in interest in its broad biological activity. In particular, thalidomide was reevaluated and attracted significant attention due to its selective inhibitory activity of tumor necrosis factor-α (TNF-α), which is a clinically important activity against serious diseases such as rheumatoid arthritis, Crohn's disease, leprosy, AIDS, and various cancers. The comeback of thalidomide to the legitimate status of a marketed drug came in 1998 when it received FDA approval for the treatment of erythema nodosum leprosum (ENL). Recently, the drug has got FDA approval for the treatment of multiple myeloma. In the last few years, number of thalidomide analogues have been synthesized and are in clinical development as a class of immunomodulatory drugs. Among these, lenalidomide is more potent than thalidomide, and is also non-neurotoxic. It was shown in vitro studies to induce apoptosis or arrest growth even in resistant multiple myeloma cell lines, decrease binding of the cells to bone marrow stromal cells, and stimulate host natural killer cell immunity. It also inhibits tumour growth and decreases angiogenesis. Earlier reviews have described the pharmacological aspects of thalidomide and a review has focused only on synthetic aspect of thalidomide. However, review focusing on chemistry and metabolism and mechanism of biological activity is still lacking. In this review, we will concisely describe the therapeutic aspects, metabolism and synthesis of thalidomide.     

S1P promotes inflammation-induced tube formation by HLECs via the S1PR1/NF-κB pathway

Inflammation-induced lymphangiogenesis is a widely accepted concept. However, most of the inflammatory factors and their related mechanisms have not been clarified. It has been reported that sphingosine-1-phosphate (S1P) is not only closely related to the chronic inflammatory process but also affects angiogenesis. Therefore, we investigated the inflammatory effects of S1P on human lymphatic endothelial cells (HLECs). Our results showed that S1P promotes tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) secretion in HLECs. We also confirmed that S1P-stimulated TNF-α and IL-1β secretion is mediated through S1P receptor 1 (S1PR1). Using TNF-α siRNA and IL-1β siRNA, we found that TNF-α and IL-1β play essential roles in S1P-induced HLEC proliferation, migration, and tube formation. S1P induces phosphorylation of NF-κB p65 and activation of NF-κB nuclear translocation. A S1PR1 antagonist (W146) and NF-κB inhibitor (BAY11-7082) inhibited S1P-induced TNF-α and IL-1β secretion and prevented NF-κB nuclear translocation. Taken together, the results demonstrated for the first time that S1P promotes the secretion of TNF-α and IL-1β in HLECs via S1PR1-mediated NF-κB signaling pathways, thus affecting lymphangiogenesis. The study provides a new strategy for finding treatments for lymphangiogenesis-related diseases.