Michael B. Sporn

Bio: Michael B. Sporn is an academic researcher from Dartmouth College. The author has contributed to research in topics: Transforming growth factor & Transforming growth factor beta. The author has an hindex of 157, co-authored 559 publications receiving 94605 citations. Previous affiliations of Michael B. Sporn include Cornell University & Reata Pharmaceuticals.

The synthetic triterpenoids CDDO-methyl ester and CDDO-ethyl amide prevent lung cancer induced by vinyl carbamate in A/J mice

Abstract: We report the first use of new synthetic triterpenoids to prevent lung cancer in experimental animals. Female A/J mice were treated with the mutagenic carcinogen vinyl carbamate, which induces adenocarcinoma of the lung in all animals within 16 weeks. If mice were fed either the methyl ester or the ethyl amide derivative of the synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO-ME and CDDO-EA, respectively), beginning 1 week after dosing with carcinogen, the number, size, and severity of lung carcinomas were markedly reduced. The mechanisms of action of CDDO-ME and CDDO-EA that are germane to these in vivo findings are the following results shown here in cell culture: (a) suppression of the ability of IFN-gamma to induce de novo formation of nitric oxide synthase in a macrophage-like cell line RAW264.7, (b) induction of heme oxygenase-1 in these RAW cells, and (c) suppression of phosphorylation of the transcription factor signal transducers and activators of transcription 3 as well as induction of apoptosis in human lung cancer cell lines.

Transforming growth factor-beta production by synovial tissues from rheumatoid patients and streptococcal cell wall arthritic rats. Studies on secretion by synovial fibroblast-like cells and immunohistologic localization.

Abstract: The growth of synovial fibroblast-like cells from patients with rheumatoid arthritis and rats with streptococcal cell wall (SCW)-induced arthritis in vitro under anchorage-independent conditions is inhibited by transforming growth factor-beta (TGF-beta). Because this growth factor is present in rheumatoid synovial fluids, we studied whether this cytokine might be secreted by cells in rheumatoid synovial tissue. We show that synovial tissues from patients with rheumatoid arthritis and osteoarthritis, and rats with SCW-induced arthritis, contain TGF-beta-1 mRNA. TGF-beta, predominantly type 1, was spontaneously secreted in vitro by synovial tissue explants and synovial fibroblast-like cells. In addition, TGF-beta could be detected immunohistochemically in cells throughout rheumatoid and SCW-induced arthritic rat synovial tissues. Finally, exogenous TGF-beta induced collagen and inhibited collagenase mRNA levels by cultured synoviocytes. These data support an autocrine role for TGF-beta in the regulation of synoviocytes in rheumatoid arthritis and, in light of its demonstrated effects on the immune system, suggest that TGF-beta might also have important paracrine effects on infiltrating inflammatory cells.

Cancer chemoprevention: scientific promise, clinical uncertainty.

Abstract: We review fundamental processes, such as mutation, oxidative stress, and inflammation that are critical for carcinogenesis and provide specific molecular targets for new chemopreventive agents. New information from molecular biology studies has identified such targets, including regulatory molecules such as Nrf2 (nuclear factor erythroid 2-related factor 2), epidermal growth factor receptor kinases, phosphatidylinositol 3-kinase, components of the Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway, nuclear factor-kappaB, and cyclin D. The development of new drugs for the control of these targets that are both safe and effective will be important for the future of cancer chemoprevention.

Novel synthetic oleanane and ursane triterpenoids with various enone functionalities in ring A as inhibitors of nitric oxide production in mouse macrophages.

Abstract: We initially randomly synthesized about 60 oleanane and ursane triterpenoids as potential anti-inflammatory and cancer chemopreventive agents. Preliminary screening of these derivatives for inhibition of production of nitric oxide induced by interferon-γ in mouse macrophages revealed that 3-oxooleana-1,12-dien-28-oic acid (B-15) showed significant activity (IC50 = 5.6 μM). On the basis of the structure of B-15, 19 novel olean- and urs-12-ene triterpenoids with a 1-en-3-one functionality having a substituent at C-2 in ring A have been designed and synthesized. Among them, 3-oxooleana-1,12-diene derivatives with carboxyl, methoxycarbonyl, and nitrile groups at C-2 showed higher activity than the lead compound B-15. In particular, 2-carboxy-3-oxooleana-1,12-dien-28-oic acid (3) had the highest activity (IC50 = 0.07 μM) in this group of triterpenoids. The potency of 3 was similar to that of hydrocortisone (IC50 = 0.01 μM), although 3 does not act through the glucocorticoid receptor. Interesting structure−acti...

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The pathogenesis of atherosclerosis: a perspective for the 1990s

Abstract: Atherosclerosis, the principal cause of heart attack, stroke and gangrene of the extremities, is responsible for 50% of all mortality in the USA, Europe and Japan. The lesions result from an excessive, inflammatory-fibroproliferative response to various forms of insult to the endothelium and smooth muscle of the artery wall. A large number of growth factors, cytokines and vasoregulatory molecules participate in this process. Our ability to control the expression of genes encoding these molecules and to target specific cell types provides opportunities to develop new diagnostic and therapeutic agents to induce the regression of the lesions and, possibly, to prevent their formation.

TGF-beta signal transduction.

Abstract: The transforming growth factor beta (TGF-beta) family of growth factors control the development and homeostasis of most tissues in metazoan organisms. Work over the past few years has led to the elucidation of a TGF-beta signal transduction network. This network involves receptor serine/threonine kinases at the cell surface and their substrates, the SMAD proteins, which move into the nucleus, where they activate target gene transcription in association with DNA-binding partners. Distinct repertoires of receptors, SMAD proteins, and DNA-binding partners seemingly underlie, in a cell-specific manner, the multifunctional nature of TGF-beta and related factors. Mutations in these pathways are the cause of various forms of human cancer and developmental disorders.