Targeting the A3 adenosine receptor to treat hepatocellular carcinoma: anti-cancer and hepatoprotective effects.

The A3 adenosine receptor (A3AR) is over-expressed in human hepatocellular carcinoma (HCC) cells. Namodenoson, an A3AR agonist, induces de-regulation of the Wnt and NF-kB signaling pathways resulting in apoptosis of HCC cells. In a phase I healthy volunteer study and in a phase I/II study in patients with advanced HCC, namodenoson was safe and well tolerated. Preliminary evidence of antitumor activity was observed in the phase I/II trial in a subset of patients with advanced disease, namely patients with Child-Pugh B (CPB) hepatic dysfunction, whose median overall survival (OS) on namodenoson was 8.1 months. A phase II blinded, randomized, placebo-controlled trial was subsequently conducted in patients with advanced HCC and CPB cirrhosis. The primary endpoint of OS superiority over placebo was not met. However, subgroup analysis of CPB7 patients (34 namodenoson-treated, 22 placebo-treated) showed nonsignificant differences in OS/progression-free survival and a significant difference in 12-month OS (44% vs 18%, p = 0.028). Partial response was achieved in 9% of namodenoson-treated patients vs 0% in placebo-treated patients. Based on the positive efficacy signal in HCC CPB7 patients and the favorable safety profile of namodenoson, a phase III study is underway.

A3 adenosine receptor allosteric modulator CF602 reverses erectile dysfunction in a diabetic rat model.

Adenosine plays a major role in erection by binding to its receptors and activating pathways resulting in increased arterial blood flow and intracavernosal pressure (ICP). CF602, an allosteric modulator of the A3 adenosine receptor (A3AR), increases the binding affinity of the endogenous adenosine to the receptor. We examined the effect of CF602 on resolving erectile dysfunction (ED) in a diabetic ED rat model (streptozotocin-induced diabetic rats that were screened for ED using the apomorphine test). ED was assessed by measuring ICP and main arterial pressure (MAP) during electrostimulation of the cavernosal nerve. A single dose of CF602 or placebo was applied either topically (100 µl from a 100 nM or 500 nM solution) or orally (100, 200 or 500 µg/kg) prior to erectile function assessment. A significant dose-dependent improvement in the ICP:MAP ratio without a change in MAP was recorded with the topical and oral CF602 treatments. A significant increase in smooth muscle:collagen ratio, vascular endothelial growth factor and endothelial nitric oxide synthase was also observed in both administration modes. In conclusion, topical and oral treatment with CF602 significantly improved erectile function, supporting its further evaluation as a treatment for ED.

Drugs Targeting the A3 Adenosine Receptor: Human Clinical Study Data.

The A3 adenosine receptor (A3AR) is overexpressed in pathological human cells. Piclidenoson and namodenoson are A3AR agonists with high affinity and selectivity to A3AR. Both induce apoptosis of cancer and inflammatory cells via a molecular mechanism entailing deregulation of the Wnt and the NF-κB signaling pathways. Our company conducted phase I studies showing the safety of these 2 molecules. In the phase II studies in psoriasis patients, piclidenoson was safe and demonstrated efficacy manifested in significant improvements in skin lesions. Namodenoson is currently being developed to treat liver cancer, where prolonged overall survival was observed in patients with advanced liver disease and a Child-Pugh B score of 7. A pivotal phase III study in this patient population has been approved by the FDA and the EMA and is currently underway. Namodenoson is also being developed to treat non-alcoholic steatohepatitis (NASH). A Phase IIa study has been successfully concluded and showed that namodenoson has anti-inflammatory, anti-fibrosis, and anti-steatosis effects. A phase IIb study in NASH is currently enrolling patients. In conclusion, A3AR agonists are promising drug candidates in advanced stages of clinical development and demonstrate safety and efficacy in their targeted indications.

Treatment of Plaque-Type Psoriasis With Oral CF101: Data from a Phase II/III Multicenter, Randomized, Controlled Trial.

BACKGROUND: CF101, an adenosine A3 receptor agonist, is an orally bioavailable small molecule drug presenting an anti-psoriatic effect demonstrated in a Phase 2 clinical trial in psoriasis patients.
OBJECTIVE: To evaluate the safety and efficacy of CF101 treatment in a Phase 2/3 study in patients with moderate to severe plaque-type psoriasis.
METHODS: This multicenter, double-blind, 2-segment, placebo-controlled study randomized subjects with moderate to severe plaque psoriasis to CF101 1 or 2 mg, or placebo twice daily. At either week 12 (Segment 1) or 16 (Segment 2), the placebo group crossed over to CF101 BID through week 32 in an open-label fashion. At week 12, following an interim analysis, the CF101 1mg group was discontinued due to futility. The primary endpoint was proportion of patients achieving ≥75% improvement in Psoriasis Area Severity Index (PASI 75). Efficacy testing was performed using the Cochran-Mantel Haenszel test, the primary analysis of PASI 75 was performed at the 0.035 significance level.
RESULTS: CF101 had an excellent safety profile at all tested dosages with a profile similar to the placebo group. The most common adverse events were infections and gastrointestinal events, and there was no cumulative intolerance over the 32-week dosing period. The study did not meet the primary endpoint of PASI 75 at week 12 (2 mg: 8.5% vs. placebo: 6.9%, P=0.621). However, at week 32, PASI mean percent improvement with CF101 2 mg was 57% (P<0.001) compared to baseline, with linear improvement in PASI 50 (63.5%), 75 (35.5%), 90 (24.7%), and 100 (10.6%).
CONCLUSIONS: Oral CF101 was found to be safe and very well tolerated, demonstrating evidence of efficacy in patients with moderate to severe plaque psoriasis through 32 weeks of treatment.

J Drugs Dermatol. 2016;15(8):931-938.

A3 adenosine receptor allosteric modulator induces an anti-inflammatory effect: in vivo studies and molecular mechanism of action.

The A3 adenosine receptor (A3AR) is overexpressed in inflammatory cells and in the peripheral blood mononuclear cells of individuals with inflammatory conditions. Agonists to the A3AR are known to induce specific anti-inflammatory effects upon chronic treatment. LUF6000 is an allosteric compound known to modulate the A3AR and render the endogenous ligand adenosine to bind to the receptor with higher affinity. The advantage of allosteric modulators is their capability to target specifically areas where adenosine levels are increased such as inflammatory and tumor sites, whereas normal body cells and tissues are refractory to the allosteric modulators due to low adenosine levels. LUF6000 administration induced anti-inflammatory effect in 3 experimental animal models of rat adjuvant induced arthritis, monoiodoacetate induced osteoarthritis, and concanavalin A induced liver inflammation in mice. The molecular mechanism of action points to deregulation of signaling proteins including PI3K, IKK, IκB, Jak-2, and STAT-1, resulting in decreased levels of NF-κB, known to mediate inflammatory effects. Moreover, LUF6000 induced a slight stimulatory effect on the number of normal white blood cells and neutrophils. The anti-inflammatory effect of LUF6000, mechanism of action, and the differential effects on inflammatory and normal cells position this allosteric modulator as an attractive and unique drug candidate.

Namodenoson at the Crossroad of Metabolic Dysfunction-Associated Steatohepatitis and Hepatocellular Carcinoma.

Namodenoson (CF102) is a small, orally available, anti-inflammatory, and anti-cancer drug candidate currently in phase 2B trial for the treatment of metabolic dysfunction-associated steatohepatitis (MASH; formerly known as non-alcoholic steatohepatitis (NASH)) and in phase 3 pivotal clinical trial for the treatment of hepatocellular carcinoma (HCC). In both MASH and HCC, the mechanism-of-action of namodenoson involves targeting the A3 adenosine receptor (A3AR), resulting in deregulation of downstream signaling pathways and leading to inhibition of inflammatory cytokines (TNF-α, IL-1, IL-6, and IL-8) and stimulation of positive cytokines (G-CSF and adiponectin). Subsequently, inhibition of liver inflammation, steatosis, and fibrosis were documented in MASH experimental models, and inhibition of HCC growth was observed in vitro, in vivo, and in clinical studies. This review discusses the evidence related to the multifaceted mechanism of action of namodenoson, and how this mechanism is reflected in the available clinical data in MASH and HCC.

A long­term complete response to namodenoson in liver cancer with Child­Pugh B cirrhosis: A case report.

Established treatments for advanced hepatocellular carcinoma (HCC) with Child-Pugh cirrhosis B (CPB, moderate hepatic dysfunction) are lacking. A recently published randomized phase 2 study in CPB HCC investigating the safety and efficacy of namodenoson (25 mg BID), an A3 adenosine-receptor agonist vs. placebo, suggested a favorable safety profile and a positive efficacy signal in patients with HCC with a CPB score of 7 (CPB7). The present study reports a 61-year-old woman with CPB7 HCC who received namodenoson for over 6 years through this study and its open-label extension. Computed tomography scans demonstrated partial and complete responses after 7 weeks and 4 years of treatment, respectively. Low albumin levels (31 g/l) and elevated baseline levels of alanine transaminase and aspartate aminotransferase (68 U/l and 44 U/l, respectively) were reported. After 4 weeks of treatment, these levels normalized and were stable for over 6 years. No treatment-emergent adverse events were noted. At the time of reporting, the response is ongoing as manifested by imaging studies and liver function evaluation.

CF102 for the treatment of hepatocellular carcinoma: a phase I/II, open-label, dose-escalation study.

BACKGROUND: The A(3) adenosine receptor (A(3)AR) is overexpressed in the tumor and in the peripheral blood mononuclear cells of patients with hepatocellular carcinoma (HCC). The orally active drug candidate CF102, an A(3)AR agonist, induces apoptosis of HCC cells via deregulation of the Wnt signaling pathway. In this open label phase I/II trial, the safety and clinical effects of CF102 were assessed in patients with advanced unresectable HCC. METHODS: The primary objectives of this trial were to examine the safety and pharmacokinetic (PK) behavior of CF102 given orally (1, 5, and 25 mg BID) in 28-day cycles. Evaluation of anti-tumor effects and the utilization of A(3)AR as a biological predictive marker of response to CF102 were the secondary objectives. RESULTS: Eighteen patients received CF102-six at each dose level. No serious drug-related adverse events or dose-limiting toxicities were observed. CF102 demonstrated good oral bioavailability and linear PK behavior. Median overall survival in the study population, 67% of whom had received prior sorafenib, was 7.8 months, and for Child Pugh B patients (28%) it was 8.1 months. Stable disease by RECIST was observed in four patients for at least 4 months. CF102 maintained liver function over a 6-month period. A correlation between receptor overexpression levels at baseline and patients' overall survival was found. One of the patients who presented with skin nodules that were biopsy-proven to be HCC metastases prior to the trial showed complete metastasis regression during three months of treatment with CF102. CONCLUSIONS: CF102 is safe and well-tolerated, showing favorable PK characteristics in Child Pugh A and B HCC patients, justifying further clinical development.

Namodenoson Inhibits the Growth of Pancreatic Carcinoma via Deregulation of the Wnt/ß-catenin, NF-κB, and RAS Signaling Pathways.

Namodenoson, an A3 adenosine receptor (A3AR) agonist, is currently being used in a phase III trial in advanced liver cancer. We examined the anti-growth effect of namodenoson on pancreatic carcinoma cells and investigated the molecular mechanism involved. BxPC-3 pancreatic carcinoma cells were cultured with namodenoson (5-20 nM for 24 h at 37 °C), and the Presto Blue assay was used to monitor cell growth. Western blot analyses were performed on BxPC-3 cells (20 nM namodenoson for 24 h at 37 °C) to evaluate the expression levels of cell growth regulatory proteins. In vivo studies involved the subcutaneous inoculation of BxPC-3 cells into nude mice, randomizing the mice into namodenoson (10 µg/kg twice daily for 35 days) vs. control, and monitoring tumor size twice weekly. Treatment with namodenoson was associated with the significant dose-dependent inhibition of BxPC-3 cell growth, which was mitigated by the A3AR antagonist MRS1523. Western blot analyses showed that namodenoson treatment modulated the expression of NF-κB, as well as proteins in the Wnt/ß-catenin and the RAS signaling pathways, leading to the upregulation of apoptotic proteins (Bad, Bax). In vivo studies also showed the significant inhibition of pancreatic carcinoma tumor growth with namodenoson. In conclusion, our findings support the continued development of namodenoson as a treatment for pancreatic cancer.

Putative role of the adenosine A(3) receptor in the antiproliferative action of N (6)-(2-isopentenyl)adenosine.

We tested a panel of naturally occurring nucleosides for their affinity towards adenosine receptors. Both N (6)-(2-isopentenyl)adenosine (IPA) and racemic zeatin riboside were shown to be selective human adenosine A(3) receptor (hA(3)R) ligands with affinities in the high nanomolar range (K (i) values of 159 and 649 nM, respectively). These values were comparable to the observed K (i) value of adenosine on hA(3)R, which was 847 nM in the same radioligand binding assay. IPA also bound with micromolar affinity to the rat A(3)R. In a functional assay in Chinese hamster ovary cells transfected with hA(3)R, IPA and zeatin riboside inhibited forskolin-induced cAMP formation at micromolar potencies. The effect of IPA could be blocked by the A(3)R antagonist VUF5574. Both IPA and reference A(3)R agonist 2-chloro-N (6)-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide (Cl-IB-MECA) have known antitumor effects. We demonstrated strong and highly similar antiproliferative effects of IPA and Cl-IB-MECA on human and rat tumor cell lines LNCaP and N1S1. Importantly, the antiproliferative effect of low concentrations of IPA on LNCaP cells could be fully blocked by the selective A(3)R antagonist MRS1523. At higher concentrations, IPA appeared to inhibit cell growth by an A(3)R-independent mechanism, as was previously reported for other A(3)R agonists. We used HPLC to investigate the presence of endogenous IPA in rat muscle tissue, but we could not detect the compound. In conclusion, the antiproliferative effects of the naturally occurring nucleoside IPA are at least in part mediated by the A(3)R.

Randomised clinical trial: A phase 2 double-blind study of namodenoson in non-alcoholic fatty liver disease and steatohepatitis.

BACKGROUND: Namodenoson, an A3 adenosine receptor (A3AR) agonist, improved liver function/pathology in non-alcoholic steatohepatitis (NASH) preclinical models. AIM: To evaluate the efficacy and safety of namodenoson for the treatment of non-alcoholic fatty liver disease (NAFLD) with or without NASH METHODS: This phase 2 study included 60 patients with NAFLD (ALT ≥60 IU/L) who were randomised (1:1:1) to oral namodenoson 12.5 mg b.d. (n = 21), 25 mg b.d. (n = 19), or placebo (n = 20) for 12 weeks (total follow-up: 16 weeks). The main efficacy endpoint involved serum ALT after 12 weeks of treatment. RESULTS: Serum ALT decreased over time with namodenoson in a dose-dependent manner. The difference between change from baseline (CFB) for ALT in the namodenoson 25 mg b.d. arm vs placebo trended towards significance at 12 weeks (P = 0.066). Serum AST levels also decreased with namodenoson in a dose-dependent manner; at 12 weeks, the CFB for 25 mg b.d. vs placebo was significant (P = 0.03). At Week 12, 31.6% in the namodenoson 25 mg b.d. arm and 20.0% in the placebo arm achieved ALT normalisation (P = 0.405). At week 16, the respective rates were 36.8% and 10.0% (P = 0.038). A3AR expression levels were stable over time across study arms. Both doses of namodenoson were well tolerated with no drug-emergent severe adverse events, drug-drug interactions, hepatotoxicity, or deaths. Three adverse events were considered possibly related to study treatment: myalgia (12.5 mg b.d. arm), muscular weakness (25 mg b.d. arm), and headache (25 mg b.d. arm). CONCLUSION: A3AR is a valid target; namodenoson 25 mg b.d. was safe and demonstrated efficacy signals (ClinicalTrials.gov #NCT02927314).

Namodenoson in Advanced Hepatocellular Carcinoma and Child-Pugh B Cirrhosis: Randomized Placebo-Controlled Clinical Trial.

Namodenoson, an A3 adenosine-receptor agonist, showed promising results in advanced hepatocellular carcinoma (HCC) and moderate hepatic dysfunction (Child-Pugh B; CPB) in a phase I/II clinical study. This phase II study investigated namodenoson as second-line therapy in such patients. Patients were randomized 2:1 to twice a day (BID) namodenoson (25 mg; n = 50) or placebo (n = 28). The primary endpoint (overall survival [OS]) was not met. Median OS was 4.1/4.3 months for namodenoson/placebo (hazard ratio [HR], 0.82; 95% confidence interval [CI] 0.49-1.38; p = 0.46). Pre-planned subgroup analysis of CPB7 patients (34 namodenoson-treated, 22 placebo-treated) showed a nonsignificant improvement in OS/progression-free survival (PFS). OS: 6.9 versus 4.3 months; HR, 0.81; 95% CI: 0.45-1.43, p = 0.46. PFS: 3.5 versus 1.9 months; HR, 0.89; 95% CI: 0.51-1.55, p = 0.67 (log-rank test). The difference in 12-month OS was significant (44% versus 18%, p = 0.028). Response rates were determined in patients for whom ≥ 1 assessment post-baseline was available (34 namodenoson-treated, 21 placebo-treated). Partial response was achieved by 3/34 (8.8%) and 0/21 (0%) patients, respectively. Namodenoson was well-tolerated, with a safety profile comparable to that of the placebo group. No treatment-related deaths were reported; no patients withdrew due to toxicity. In conclusion, namodenoson demonstrated a favorable safety profile and a preliminary efficacy signal in HCC CPB.

Treatment of dry eye syndrome with orally administered CF101: data from a phase 2 clinical trial.

OBJECTIVE: To explore the safety and efficacy of CF101, an A(3) adenosine receptor agonist, in patients with moderate to severe dry eye syndrome. DESIGN: Phase 2, multicenter, randomized, double-masked, placebo-controlled, parallel-group study. PARTICIPANTS: Sixty-eight patients completed the study, 35 patients in the placebo group and 33 patients in the CF101 group. INTERVENTION: Patients were treated orally with either 1 mg CF101 pills or matching vehicle-filled placebo pills, given twice daily for 12 weeks, followed by a 2-week posttreatment observation. MAIN OUTCOME MEASURES: An improvement of more than 25% over baseline at week 12 in one of the following parameters: (1) tear break-up time (BUT); (2) superficial punctate keratitis assessed by fluorescein staining results; and (3) Schirmer tear test 1 results. Clinical laboratory safety tests, ophthalmic examinations, intraocular pressure (IOP) measurements, electrocardiographic evaluations, vital sign measurements, and monitoring of adverse events. RESULTS: A statistically significant increase in the proportion of patients who achieved more than 25% improvement in the corneal staining and in the clearance of corneal staining was noted between the CF101-treated group and the placebo group. Treatment with CF101 resulted in a statistically significant improvement in the mean change from baseline at week 12 of the corneal staining, BUT, and tear meniscus (TM) height in the CF101-treated group. CF101 was well tolerated and exhibited an excellent safety profile with no serious adverse events. A statistically significant decrease from baseline was observed in the IOP of the CF101-treated group in comparison with the placebo group. CONCLUSIONS: CF101, given orally, induced a statistically significant improvement in the corneal staining and an improvement in the BUT and TM in patients with moderate to severe dry eye syndrome. The drug was very well tolerated. These data and the anti-inflammatory characteristic of CF101 support further study of the drug as a potential treatment for the signs and symptoms of dry eye syndrome. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Targeting the A3 adenosine receptor to treat cytokine release syndrome in cancer immunotherapy.

Cancer patients undergoing immunotherapy may develop cytokine release syndrome (CRS), an inflammatory cytokine storm condition, followed by neurotoxic manifestations and may be life-threatening. The current treatments for CRS successfully reduce the inflammatory response but may limit the anticancer effect of the given immunotherapy and fail to overcome the neurotoxic adverse events. Adenosine, a ubiquitous purine nucleoside, induces a plethora of effects in the body via its binding to four adenosine receptors A1, A2a, A2b, and the A3. Highly selective agonists to the A3 adenosine receptor act as inhibitors of proinflammatory cytokines, possess robust anti-inflammatory and anticancer activity, and concomitantly, induce neuroprotective effects. Piclidenoson and namodenoson belong to this group of compounds, are effective upon oral administration, show an excellent safety profile in human clinical studies, and therefore, may be considered as drug candidates to treat CRS. In this article, the detailed anti-inflammatory characteristics of these compounds and the rationale to use them as drugs to combat CRS are described.

The A3 adenosine receptor agonist, namodenoson, ameliorates non­alcoholic steatohepatitis in mice.

The Wnt/ß­catenin pathway confers a chain of molecular events in livers affected by non­alcoholic steatohepatitis (NASH). Namodenoson, a selective agonist of the A3 adenosine receptor (A3AR), which is highly expressed in pathological liver cells, induces a robust anti­inflammatory effect in the liver, mediated via the de­regulation of the Wnt/ß­catenin pathway. Namodenoson also acts as a liver protective agent by inhibiting ischemia/reperfusion injury. Based on these unique characteristics, we investigated the anti­NASH effect of Namodenoson in murine models of steatohepatitis and in the LX2 human hepatic stellate cell line (HSC). In the STAM model, Namodenoson significantly decreased the non­alcoholic fatty liver disease (NAFLD) activity score, NAS, demonstrating anti­inflammatory and anti­steatotic effects. In the carbon tetrachloride (CCl4) model, Namodenoson reversed alanine aminotransferase (ALT) to normal values and significantly improved liver inflammation and fibrosis, as well as the adiponectin and leptin levels. Namodenoson de­regulated the Wnt/ß­catenin pathway in the liver extracts of the CCl4 model mice and in the LX2 HSCs, manifested by a decrease in the expression of phosphoinositide 3­kinase (PI3K), nuclear factor κ­light­chain­enhancer of activated B cells (NF­κB), ß­catenin, lymphoid enhancer­binding factor 1 (Lef­1) and cyclin D1, and an increase in the expression level of glycogen synthase kinase 3ß (GSK­3ß). The fibrosis marker, α­smooth muscle actin (α­SMA) was also de­regulated, supporting the anti­fibrotic effect of Namodenoson. On the whole, the findings of this study demonstrate that Namodenoson exerts an anti­NASH effect mediated via the de­regulation of the PI3K/NF­κB/Wnt/ß­catenin signaling pathway. Thus, targeting A3AR may prove to be a novel direction in the pharmacotherapy of NAFLD/NASH.

Inhibition of IL-17 and IL-23 in Human Keratinocytes by the A3 Adenosine Receptor Agonist Piclidenoson.

Interleukin-17 and interleukin-23 play major roles in the inflammatory process in psoriasis. The Gi protein-associated A3 adenosine receptor (A3AR) is known to be overexpressed in inflammatory cells and in peripheral blood mononuclear cells (PBMCs) of patients with autoimmune inflammatory conditions. Piclidenoson, a selective agonist at the A3AR, induces robust anti-inflammatory effect in psoriasis patients. In this study, we aimed to explore A3AR expression levels in psoriasis patients and its role in mediating the anti-inflammatory effect of piclidenoson in human keratinocyte cells. A3AR expression levels were evaluated in skin tissue and PBMCs derived from psoriasis patients and healthy subjects. Proliferation assay and the expression of signaling proteins were used to evaluate piclidenoson effect on human keratinocytes (HaCat). High A3AR expression levels were found in a skin biopsy and in PBMCs from psoriasis patients in comparison to healthy subjects. Piclidenoson inhibited the proliferation of HaCat cells through deregulation of the NF-κB signaling pathway, leading to a decrease in interleukin-17 and interleukin-23 expression levels. This effect was counteracted by the specific antagonist MRS 1523. A3AR overexpression in skin and PBMCs of psoriasis patients may be used as a target to inhibit pathological cell proliferation and the production of interleukin-17 and interleukin-23.

The A3 adenosine receptor (A3AR): therapeutic target and predictive biological marker in rheumatoid arthritis.

The Gi protein-associated A3 adenosine receptor (A3AR) is over-expressed in inflammatory cells, and this high expression is also reflected in the peripheral blood mononuclear cells of patients with autoimmune inflammatory diseases such as rheumatoid arthritis, psoriasis, and Crohn's disease. CF101, a selective agonist with high affinity to the A3AR, is known to induce robust anti-inflammatory effect in experimental animal models of adjuvant-, collagen-, and tropomyosin-induced arthritis. The effect is mediated via a definitive molecular mechanism entailing deregulation of the nuclear factor-κB (NF-κB) and the Wnt signal transduction pathways resulting in apoptosis of inflammatory cells. CF101 was found to be safe and well tolerated in all preclinical, phase I, and phase II human clinical studies. In two phase II clinical studies where CF101 was administered to rheumatoid arthritis (RA) patients as a stand-alone drug, a significant anti-rheumatic effect and a direct significant correlation were found between receptor expression at baseline and patients' response to the drug, suggesting that A3AR may be utilized as a predictive biomarker. The A3AR is a promising therapeutic target in rheumatoid arthritis and can be used also as a biological marker to predict patients' response to CF101. This is a unique type of a personalized medicine approach which may pave the way for a safe and efficacious treatment for this patient population.

A3 adenosine receptor agonist, CF102, protects against hepatic ischemia/reperfusion injury following partial hepatectomy.

Ischemia/reperfusion (IR) injury during clinical hepatic procedures is characterized by inflammatory conditions and the apoptosis of hepatocytes. Nuclear factor­κB (NF­κB), nitric oxide and the expression levels of inflammatory cytokines, tumor necrosis factor­α and interleukin­1 were observed to increase following IR and mediate the inflammatory response in the liver. CF102 is a highly selective A3 adenosine receptor (A3AR) agonist, and has been identified to induce an anti­inflammatory and protective effect on the liver via the downregulation of the NF­κB signaling pathway. The present study aimed to determine the effect of CF102 on protecting the liver against IR injury. The potential protective effect of CF102 (100 µg/kg) was assessed using an IR injury model on 70% of the liver of Wistar rats, which was induced by clamping the hepatic vasculature for 30 min. The regenerative effect of CF102 was assessed by the partial hepatectomy of 70% of the liver during 10 min of IR. CF102 reduced the levels of liver enzymes following IR injury. A higher regeneration rate in the CF102 treatment group was observed compared with the control group, suggesting that CF102 had a positive effect on the proliferation of hepatocytes following hepatectomy. CF102 had a protective effect on the liver of Wistar rats subsequent to IR injury during hepatectomy. This may be due to an anti­inflammatory and anti­apoptotic effect mediated by the A3AR.

Evidence for involvement of Wnt signaling pathway in IB-MECA mediated suppression of melanoma cells.

The A3 adenosine receptor, A3AR, belongs to the family of Gi proteins, which upon induction, suppresses the formation of cAMP and its downstream effectors. Recent studies have indicated that activation of A3AR by its agonist, IB-MECA, results in growth inhibition of malignant cells. Here we demonstrate the ability of IB-MECA to decrease the levels of protein kinase A, a downstream effector of cAMP, and protein kinase B/Akt in melanoma cells. Examination of glycogen synthase kinase 3beta, GSK-3beta, whose phosphorylation is controlled by protein kinase A and B, showed a substantial decrease in the levels of its phosphorylated form and an increase in total GSK-3beta levels in IB-MECA treated melanoma cells. This observation suggests that the treatment of cells with IB-MECA augments the activity of GSK-3beta in the cells. Evaluation of beta-catenin, a key component of Wnt signaling pathway which, upon phosphorylation by GSK-3beta rapidly ubiquitinates, showed a substantial decrease in its level after IB-MECA treatment. Accordingly, the level of beta-catenin responsive cell growth regulatory genes including c-myc and cyclin D1 was severely declined upon treatment of the cells with IB-MECA. These observations which link cAMP to the Wnt signaling pathway provide mechanistic evidence for the involvement of Wnt pathway via its key elements GSK-3beta and beta-catenin in the anti-tumor activity of A3AR agonists.