Rheumatoid Arthritis: Bar-Yehuda S

Bar-Yehuda S, Silverman MH, Kerns WD, Ochaion A, Cohen S, Fishman P. · Can-Fite BioPharma, 10 Bareket Street, PO Box 7537, Petach-Tikva 49170, Israel. · Expert Opin Investig Drugs. · Pubmed #17922624 No free full text.

Abstract: Targeting the A(3) adenosine receptor (A(3)AR) to combat inflammation is a new concept based on two findings. First, A(3)AR is highly expressed in inflammatory cells, whereas low expression is found in normal tissues. This receptor was also found to be overexpressed in peripheral blood mononuclear cells, reflecting receptor status in the remote inflammatory process. Second, A(3)AR activation with a specific agonist induces de-regulation of the NF-kappaB signaling pathway in inflammatory cells, as well as initiation of immunomodulatory effects. The A(3)AR agonist CF-101 (known generically as IB-MECA) induces anti-inflammatory effects in experimental animal models of collagen- and adjuvant-induced arthritis. Combined therapy with CF-101 and methotrexate in adjuvant-induced arthritis rats yielded an additive anti-inflammatory effect. Methotrexate induced upregulation of A(3)AR, rendering the inflammatory cells more susceptible to CF-101. In Phase I and in Phase IIa human studies, CF-101 was safe, well tolerated and showed strong evidence of an anti-inflammatory effect in rheumatoid arthritis patients. In peripheral blood mononuclear cells withdrawn from the patients at base line, a statistically significant correlation between A(3)AR expression level and response to the drug was noted. It is suggested that A(3)AR may serve as a biologic marker to predict patient response to the drug. Taken together, this information suggests that A(3)AR agonists may be a new family of orally bioavailable drugs to be developed as potent inhibitors of autoimmune-inflammatory diseases.

Ochaion A, Bar-Yehuda S, Cohen S, Barer F, Patoka R, Amital H, Reitblat T, Reitblat A, Ophir J, Konfino I, Chowers Y, Ben-Horin S, Fishman P. · Can-Fite BioPharma Ltd., Kiryat-Matalon, Petah-Tikva, Israel. · Cell Immunol. · Pubmed #19426966 No free full text.

Abstract: The Gi protein associated A(3) adenosine receptor (A(3)AR) was recently defined as a novel anti-inflammatory target. The aim of this study was to look at A(3)AR expression levels in peripheral blood mononuclear cells (PBMCs) of patients with autoimmune inflammatory diseases and to explore transcription factors involved receptor expression. Over-expression of A(3)AR was found in PBMCs derived from patients with rheumatoid arthritis (RA), psoriasis and Crohn's disease compared with PBMCs from healthy subjects. Bioinformatics analysis demonstrated the presence of DNA binding sites for nuclear factor-kappaB (NF-kappaB) and cyclic AMP-responsive element binding protein (CREB) in the A(3)AR gene promoter. Up-regulation of NF-kappaB and CREB was found in the PBMCs from patients with RA, psoriasis and Crohn's disease. The PI3K-PKB/Akt signaling pathway, known to regulate both the NF-kappaB and CREB, was also up-regulated in the patients' PBMCs. Taken together, NF-kappaB and CREB are involved with the over-expression of A(3)AR in patients with autoimmune inflammatory diseases. The receptor may be considered as a specific target to combat inflammation.

Ochaion A, Bar-Yehuda S, Cohen S, Amital H, Jacobson KA, Joshi BV, Gao ZG, Barer F, Patoka R, Del Valle L, Perez-Liz G, Fishman P. · Can-Fite BioPharma Ltd., Kiryat-Matalon, Petah-Tikva 49170, Israel. · Biochem Pharmacol. · Pubmed #18602896 No free full text.

Abstract: The A(3) adenosine receptor (A(3)AR) is over-expressed in inflammatory cells and was defined as a target to combat inflammation. Synthetic agonists to this receptor, such as IB-MECA and Cl-IB-MECA, exert an anti-inflammatory effect in experimental animal models of adjuvant- and collagen-induced arthritis. In this study we present a novel A(3)AR agonist, CF502, with high affinity and selectivity at the human A(3)AR. CF502 induced a dose dependent inhibitory effect on the proliferation of fibroblast-like synoviocytes (FLS) via de-regulation of the nuclear factor-kappa B (NF-kappaB) signaling pathway. Furthermore, CF502 markedly suppressed the clinical and pathological manifestations of adjuvant-induced arthritis (AIA) in a rat experimental model when given orally at a low dose (100 microg/kg). As is typical of other G-protein coupled receptors, the A(3)AR expression level was down-regulated shortly after treatment with agonist CF502 in paw and in peripheral blood mononuclear cells (PBMCs) derived from treated AIA animals. Subsequently, a decrease in the expression levels of protein kinase B/Akt (PKB/Akt), IkappaB kinase (IKK), I kappa B (IkappaB), NF-kappaB and tumor necrosis factor-alpha (TNF-alpha) took place. In addition, the expression levels of glycogen synthase kinase-3 beta (GSK-3beta), beta-catenin, and poly(ADP-ribose)polymerase (PARP), known to control the level and activity of NF-kappaB, were down-regulated upon treatment with CF502. Taken together, CF502 inhibits FLS growth and the inflammatory manifestations of arthritis, supporting the development of A(3)AR agonists for the treatment of rheumatoid arthritis.

Madi L, Cohen S, Ochayin A, Bar-Yehuda S, Barer F, Fishman P. · Can-Fite BioPharma Ltd., Kiryat-Matalon, Petah-Tikva, Israel. · J Rheumatol. · Pubmed #17216675 No free full text.

Abstract: OBJECTIVE: A3 adenosine receptor (A3AR) upregulation has been found in cells of synovial tissue and in peripheral blood mononuclear cells (PBMC) of rats with adjuvant-induced arthritis. We investigated A3AR levels in PBMC of patients with rheumatoid arthritis (RA) and in mitogen-activated PBMC from healthy subjects. We examined the role of nuclear factor-kappaB (NF-kappaB), a transcription factor present in the A3AR promoter, in mediating receptor upregulation. METHODS: A3AR and NF-kappaB protein levels were evaluated in PBMC of RA patients (n = 23) and healthy subjects by Western blot. A3AR and NF-kappaB levels were also analyzed in phytohemagglutinin (PHA) and lipopolysaccharide (LPS)-stimulated PBMC in the presence and absence of antibodies against interleukin 2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha). Reverse transcription-polymerase chain reaction was performed in PHA-stimulated PBMC of healthy subjects to determine A3AR expression. RESULTS: A3AR was overexpressed in PBMC of RA patients compared to healthy subjects and was directly correlated to an increase in NF-kappaB. Similar findings were observed in PHA and LPS-stimulated PBMC from healthy subjects. Antibodies against IL-2 or TNF-alpha prevented the increase in A3AR and NF-kappaB expression. CONCLUSION: Overexpression of A3AR was found in PBMC of RA patients. Receptor upregulation was induced by inflammatory cytokines controlling the expression of the A3AR transcription factor NF-kappaB.

Ochaion A, Bar-Yehuda S, Cohn S, Del Valle L, Perez-Liz G, Madi L, Barer F, Farbstein M, Fishman-Furman S, Reitblat T, Reitblat A, Amital H, Levi Y, Molad Y, Mader R, Tishler M, Langevitz P, Zabutti A, Fishman P. · Can-Fite Biopharma Ltd, 10 Bareket Street, Kiryat-Matalon, Petah-Tikva, 49170, Israel. · Arthritis Res Ther. · Pubmed #17101059 links to  free full text

Abstract: Methotrexate (MTX) exerts an anti-inflammatory effect via its metabolite adenosine, which activates adenosine receptors. The A3 adenosine receptor (A3AR) was found to be highly expressed in inflammatory tissues and peripheral blood mononuclear cells (PBMCs) of rats with adjuvant-induced arthritis (AIA). CF101 (IB-MECA), an A3AR agonist, was previously found to inhibit the clinical and pathological manifestations of AIA. The aim of the present study was to examine the effect of MTX on A3AR expression level and the efficacy of combined treatment with CF101 and MTX in AIA rats. AIA rats were treated with MTX, CF101, or both agents combined. A3AR mRNA, protein expression and exhibition were tested in paw and PBMC extracts from AIA rats utilizing immunohistochemistry staining, RT-PCR and Western blot analysis. A3AR level was tested in PBMC extracts from patients chronically treated with MTX and healthy individuals. The effect of CF101, MTX and combined treatment on A3AR expression level was also tested in PHA-stimulated PBMCs from healthy individuals and from MTX-treated patients with rheumatoid arthritis (RA). Combined treatment with CF101 and MTX resulted in an additive anti-inflammatory effect in AIA rats. MTX induced A2AAR and A3AR over-expression in paw cells from treated animals. Moreover, increased A3AR expression level was detected in PBMCs from MTX-treated RA patients compared with cells from healthy individuals. MTX also increased the protein expression level of PHA-stimulated PBMCs from healthy individuals. The increase in A3AR level was counteracted in vitro by adenosine deaminase and mimicked in vivo by dipyridamole, demonstrating that receptor over-expression was mediated by adenosine. In conclusion, the data presented here indicate that MTX induces increased A3AR expression and exhibition, thereby potentiating the inhibitory effect of CF101 and supporting combined use of these drugs to treat RA.