Inhibition of the aryl hydrocarbon receptor/polyamine biosynthesis axis suppresses multiple myeloma.

Polyamine inhibition for cancer therapy is, conceptually, an attractive approach but has yet to meet success in the clinical setting. The aryl hydrocarbon receptor (AHR) is the central transcriptional regulator of the xenobiotic response. Our study revealed that AHR also positively regulates intracellular polyamine production via direct transcriptional activation of 2 genes, ODC1 and AZIN1, which are involved in polyamine biosynthesis and control, respectively. In patients with multiple myeloma (MM), AHR levels were inversely correlated with survival, suggesting that AHR inhibition may be beneficial for the treatment of this disease. We identified clofazimine (CLF), an FDA-approved anti-leprosy drug, as a potent AHR antagonist and a suppressor of polyamine biosynthesis. Experiments in a transgenic model of MM (Vk*Myc mice) and in immunocompromised mice bearing MM cell xenografts revealed high efficacy of CLF comparable to that of bortezomib, a first-in-class proteasome inhibitor used for the treatment of MM. This study identifies a previously unrecognized regulatory axis between AHR and polyamine metabolism and reveals CLF as an inhibitor of AHR and a potentially clinically relevant anti-MM agent.

Anti-cancer effect of clofazimine as a single agent and in combination with cisplatin on U266 multiple myeloma cell line.

Multiple Myeloma (MM) is a malignant neoplasm of bone marrow plasma B cells with high morbidity. Clofazimine (CLF) is an FDA-approved leprostatic, anti-tuberculosis, and anti-inflammatory drug that was previously shown to have growth suppression effect on various cancer types such as hepatocellular, lung, cervix, esophageal, colon, and breast cancer as well as melanoma, neuroblastoma, and leukemia. The objective of this study was to evaluate the anticancer effect and mechanism of CLF on U266 MM cell line. CLF (10µM, 24h) treatment resulted up to 72% growth suppression on a panel of hematological cell lines. Dose-response study conducted on U266 MM cell line revealed an IC50 value of 9.8±0.7µM. CLF also showed a synergistic inhibition effect in combination with cisplatin. In mechanistic assays, CLF treatment caused mitochondrial membrane depolarization, change in cell membrane asymmetry and increase in caspase-3 activity; indicating to an intrinsic apoptosis mechanism. This study provides new evidence for the anticancer effect of CLF on U266 cell line. Further in vivo and clinical studies are warranted to evaluate its therapeutic potential for MM treatment.

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.

Cutaneous vasculitis as a presenting feature of multiple myeloma: a report of 2 cases.

We report two male patients who presented with symmetrical, painful purpura that evolved into bullae and necrotic ulcers, predominantly on the extremities, over two months in spite of conventional therapy including oral steroids. Examination showed livedoid and purpuric patches with necrotic centers in starburst pattern over the extremities and buttocks. The first case also had similar lesions over the ears. The clinical presentation and the histopathological examination suggested a diagnosis of necrotizing leukocytoclastic vasculitis (LCV). Blood testing ruled out connective tissue disease, hepatitis B or C infection or streptococcal infection as underlying cause of vasculitis. Serum antinuclear factor, antineutrophilic cytoplasmic antibody and anticardiolipin anticoagulant were negative in both cases. Cryoglobulins were positive in case 2. An incidental finding was raised serum proteins and globulins in case 2. Further investigations revealed M band on electrophoresis and features of multiple myeloma on bone marrow biopsy in both cases. These cases emphasize the importance of simple investigations like serum proteins in the evaluation of LCV.

Mechanisms of action and potential therapeutic uses of thalidomide.

Thalidomide was first introduced to the market in Germany under the brand name of Contergan in 1956, as a non-barbiturate hypnotic, advocated to ensure a good nights sleep and to prevent morning sickness in pregnancy. It was advertised for its prompt action, lack of hangover, and apparent safety. It has been banned from the market since 1963 after it caused the worldwide teratogenic disaster: babies exposed to thalidomide in utero during the first 34-50 days of pregnancy were born with severe life-threatening birth defects. Despite its unfortunate history, thalidomide has attracted scientific interest again because of its recently discovered action against inflammatory diseases and cancer. Its broad range of biological activities stems from its ability to moderate cytokine action in cancer and inflammatory diseases. Early studies examined its anxiolytic, mild hypnotic, antiemetic, and adjuvant analgesic properties. Subsequently, thalidomide was found to be highly effective in managing the cutaneous manifestations of leprosy, being superior to Aspirin in controlling leprosy-associated fever. Recent research has shown promising results with thalidomide in patients with myeloma, myelodysplastic syndrome, a variety of infectious diseases, autoimmune diseases, cancer, and progressive body weight loss related to advanced cancer and AIDS. Here we review the history of its development, pharmacokinetics, metabolism, biologic effects, and the results of clinical trials conducted thus far. Further research in this field should be directed towards better understanding of thalidomide metabolism, its mechanism of action, and the development of less toxic and more active analogs.

[Role of thalidomide in the treatment of multiple myeloma]. / A thalidomid szerepe a myeloma multiplex gyógykezelésében.

Multiple myeloma is a relatively common hematologic malignancy with no definitive treatment available. Although, therapy may include allogenic bone marrow transplantation, high-dose ablative chemotherapy followed by bone marrow or peripheral stem cell transplantation, melphalan/corticosteroid therapy, alpha-interferon treatment, and combined cytostatic chemotherapy, currently none of these alternatives offers cure for the disease. Thalidomide is an infamous molecule for its teratogenicity, yet it possesses potent immunomodulatory, anti-angiogeneic and, in higher concentrations, direct anti-myeloma-cell properties. At present, the drug is only approved for the treatment of erythema nodosum of leprosy, however, there are several preliminary results that show clinical efficacy in multiple myeloma. This drug has especially potent anti-myeloma effects in combinations with dexamethasone and certain cytostatic chemotherapeutic agents. The effects are evident both in polyresistant, and relapsing myeloma, a form with no accepted effective treatment options. In this paper, the fundamental molecular and cellular effects of thalidomide are summarized then the most important clinical studies with thalidomide are reviewed. It is the authors' hope that thalidomide will soon be a full member of the medical arsenal in the fight against multiple myeloma.

Dermatoses do pavilhäo auricular / External ear dermatosis

Apresentamos uma atualizaçäo sobre as dermatoses que ocorrem no pavilhäo auricular. Propomos uma classificaçäo em sete grupos e realizamos uma sucinta descriçäo clínica de cada uma das 84 entidades catalogadas, de forma didática, com a finalidade de auxiliar o médico, sobretudo o clínico geral, o dermatologista e o otorrinolaringologista, no diagnóstico de tais patologias.