Practical Guidance for the Management of Adverse Events in Patients with KRASG12C-Mutated Non-Small Cell Lung Cancer Receiving Adagrasib.

Adagrasib (MRTX849) is a KRASG12C inhibitor with favorable properties, including long half-life (23 h), dose-dependent pharmacokinetics, and central nervous system (CNS) penetration. As of September 1, 2022, a total of 853 patients with KRASG12C-mutated solid tumors, including patients with CNS metastases, had received adagrasib (monotherapy or in combination). Adagrasib-related treatment-related adverse events (TRAEs) are generally mild to moderate in severity, start early in treatment, resolve quickly with appropriate intervention, and result in a low rate of treatment discontinuation. Common TRAEs seen in clinical trials included gastrointestinal-related toxicities (diarrhea, nausea, and vomiting); hepatic toxicities (increased alanine aminotransferase/aspartate aminotransferase) and fatigue, which can be managed through dose modifications, dietary modifications, concomitant medications (such as anti-diarrheals and anti-emetics/anti-nauseants) and the monitoring of liver enzymes and electrolytes. To manage common TRAEs effectively, it is imperative that clinicians are informed, and patients are fully counseled on management recommendations at treatment initiation. In this review, we provide practical guidance on the management of adagrasib TRAEs and discuss some best practices for patient and caregiver counseling to facilitate optimal outcomes for patients. Safety and tolerability data from the phase II cohort of the KRYSTAL-1 study will be reviewed and presented with practical management recommendations based on our experience as clinical investigators.

Effective treatment of low-risk acute GVHD with itacitinib monotherapy.

The standard primary treatment for acute graft-versus-host disease (GVHD) requires prolonged, high-dose systemic corticosteroids (SCSs) that delay reconstitution of the immune system. We used validated clinical and biomarker staging criteria to identify a group of patients with low-risk (LR) GVHD that is very likely to respond to SCS. We hypothesized that itacitinib, a selective JAK1 inhibitor, would effectively treat LR GVHD without SCS. We treated 70 patients with LR GVHD in a multicenter, phase 2 trial (NCT03846479) with 28 days of itacitinib 200 mg/d (responders could receive a second 28-day cycle), and we compared their outcomes to those of 140 contemporaneous, matched control patients treated with SCSs. More patients responded to itacitinib within 7 days (81% vs 66%, P = .02), and response rates at day 28 were very high for both groups (89% vs 86%, P = .67), with few symptomatic flares (11% vs 12%, P = .88). Fewer itacitinib-treated patients developed a serious infection within 90 days (27% vs 42%, P = .04) due to fewer viral and fungal infections. Grade ≥3 cytopenias were similar between groups except for less severe leukopenia with itacitinib (16% vs 31%, P = .02). No other grade ≥3 adverse events occurred in >10% of itacitinib-treated patients. There were no significant differences between groups at 1 year for nonrelapse mortality (4% vs 11%, P = .21), relapse (18% vs 21%, P = .64), chronic GVHD (28% vs 33%, P = .33), or survival (88% vs 80%, P = .11). Itacitinib monotherapy seems to be a safe and effective alternative to SCS treatment for LR GVHD and deserves further investigation.

Adagrasib in Non-Small-Cell Lung Cancer Harboring a KRASG12C Mutation.

BACKGROUND: Adagrasib, a KRASG12C inhibitor, irreversibly and selectively binds KRASG12C, locking it in its inactive state. Adagrasib showed clinical activity and had an acceptable adverse-event profile in the phase 1-1b part of the KRYSTAL-1 phase 1-2 study. METHODS: In a registrational phase 2 cohort, we evaluated adagrasib (600 mg orally twice daily) in patients with KRASG12C -mutated non-small-cell lung cancer (NSCLC) previously treated with platinum-based chemotherapy and anti-programmed death 1 or programmed death ligand 1 therapy. The primary end point was objective response assessed by blinded independent central review. Secondary end points included the duration of response, progression-free survival, overall survival, and safety. RESULTS: As of October 15, 2021, a total of 116 patients with KRASG12C -mutated NSCLC had been treated (median follow-up, 12.9 months); 98.3% had previously received both chemotherapy and immunotherapy. Of 112 patients with measurable disease at baseline, 48 (42.9%) had a confirmed objective response. The median duration of response was 8.5 months (95% confidence interval [CI], 6.2 to 13.8), and the median progression-free survival was 6.5 months (95% CI, 4.7 to 8.4). As of January 15, 2022 (median follow-up, 15.6 months), the median overall survival was 12.6 months (95% CI, 9.2 to 19.2). Among 33 patients with previously treated, stable central nervous system metastases, the intracranial confirmed objective response rate was 33.3% (95% CI, 18.0 to 51.8). Treatment-related adverse events occurred in 97.4% of the patients - grade 1 or 2 in 52.6% and grade 3 or higher in 44.8% (including two grade 5 events) - and resulted in drug discontinuation in 6.9% of patients. CONCLUSIONS: In patients with previously treated KRASG12C -mutated NSCLC, adagrasib showed clinical efficacy without new safety signals. (Funded by Mirati Therapeutics; ClinicalTrials.gov number, NCT03785249.).

Determination of Afatinib in Human Plasma by 2-Dimensional Liquid Chromatography.

INTRODUCTION: A simple, sensitive, rapid, and practical 2-dimensional liquid chromatography (2D-LC) method was developed and validated for the quantification of a 500-µL afatinib sample extracted from human plasma. METHODS: The plasma samples were pretreated with acetonitrile for protein precipitation. The mobile phase consisted of a first-dimensional mobile phase (acetonitrile, methanol, and 25 mmol/L ammonium phosphate in a ratio of 25:25:50, V/V/V) and a second-dimensional mobile phase (acetonitrile and 10 mmol/L ammonium phosphate in a ratio of 25:75, V/V). The average recovery of the plasma samples was stable and reproducible (98.56%-100.02%). RESULTS: The analyte was sufficiently stable for handling and analysis. The calibration curve was linear, ranging from 10.93 to 277.25 ng/mL with regression equation y = 804.60 x - 4,169.87 (R2 = 0.999). The relative standard deviations for accuracy and precision studies were within ±2.30% and <3.41%, respectively (intra- and interday). Finally, the validated method was successfully employed to determine the drug levels in plasma from the patients treated with afatinib. In clinical assessment, the patients with gastric cancer were orally administered with 30 or 40 mg per day of afatinib, which resulted in large plasma concentrations, ranging from 5.52 to 45.16 ng/mL. CONCLUSION: The results indicated that this method was useful for the therapeutic drug monitoring of afatinib and suitable for the assessment of the risks and benefits of chemotherapy in patients with non-small cell lung cancer.

A Mini Review on Characteristics and Analytical Methods of Otilonium Bromide.

Irritable bowel syndrome (IBS) is a world-wide disease prevalently in Western nations. It influences about 15% of the western populace, with a negative effect on the quality of life and furthermore on medical services costs. Anticholinergic antispasmodics are first line of treatment for discomfort or abdominal pain, particularly if unrelieved after alleviation of stoppage or antidiarrheal treatment. Otilonium bromide (OTB) is quaternary ammonium compound with action on distal GI tract as antispasmodic. It is utilized in the treatment of patients influenced by Irritable inside disorder (IBS) because of its particular pharmacokinetic and pharmacodynamic properties. OTB is poorly absorbed systematically was viable in contrast with different medications used for same purpose, for example, pinaverium bromide and mebeverine, with a good tolerability profile. The effects are long lasting, even after stopping the dosage regime for reduction of abdominal pain. In this review, an overview of mechanism of action, pharmacologic action, synthesis and particularly various analytical and bioanalytical methods are discussed. The analytical methods discussed are spectrophotometry including Near Infrared Spectroscopy (NIRS), chromatography and capillary electrophoresis methods are described with the range, limit of detection and quantification. The paper also provides details of scope of further extension of analytical methods. It was found that most of the analytical methods involves usage of toxic solvents e.g., methanol, acetonitrile, chloroform etc. posing risk to the analyst as well as environment.

KRAS G12C fragment screening renders new binding pockets.

KRAS genes belong to the most frequently mutated family of oncogenes in cancer. The G12C mutation, found in a third of lung, half of colorectal and pancreatic cancer cases, is believed to be responsible for a substantial number of cancer deaths. For 30 years, KRAS has been the subject of extensive drug-targeting efforts aimed at targeting KRAS protein itself, but also its post-translational modifications, membrane localization, protein-protein interactions and downstream signalling pathways. So far, most KRAS targeting strategies have failed, and there are no KRAS-specific drugs available. However, clinical candidates targeting the KRAS G12C protein have recently been developed. MRTX849 and recently approved Sotorasib are covalent binders targeting the mutated cysteine 12, occupying Switch II pocket.Herein, we describe two fragment screening drug discovery campaigns that led to the identification of binding pockets on the KRAS G12C surface that have not previously been described. One screen focused on non-covalent binders to KRAS G12C, the other on covalent binders.

Targeting Mutated KRAS Genes to Treat Solid Tumours.

Kirsten rat sarcoma (KRAS) is one of the most frequently mutated oncogenes in solid tumours. It encodes an important signalling pathway that drives cellular proliferation and growth. It is frequently mutated in aggressive advanced solid tumours, particularly colorectal, lung and pancreatic cancer. Since the first mutated KRAS was discovered in the 1980s, decades of research to develop targeted inhibitors of mutant KRAS have fallen short of the task, until recently. Multiple agents are now in clinical trials, including specific mutant KRAS inhibitors, pan-KRAS inhibitors, therapeutic vaccines and other targeted inhibitors. Mutant-specific KRAS G12C inhibitors are the most advanced, with two inhibitors, adagrasib and sotorasib, achieving approval in 2021 for the second-line treatment of patients with KRAS G12C mutant lung cancer. In this review, we summarise the importance of mutant KRAS in solid tumours, prior attempts at inhibiting mutant KRAS, and the current promising targeted agents being investigated in clinical trials, along with future challenges.

Acquired Resistance to KRASG12C Inhibition in Cancer.

BACKGROUND: Clinical trials of the KRAS inhibitors adagrasib and sotorasib have shown promising activity in cancers harboring KRAS glycine-to-cysteine amino acid substitutions at codon 12 (KRASG12C). The mechanisms of acquired resistance to these therapies are currently unknown. METHODS: Among patients with KRASG12C -mutant cancers treated with adagrasib monotherapy, we performed genomic and histologic analyses that compared pretreatment samples with those obtained after the development of resistance. Cell-based experiments were conducted to study mutations that confer resistance to KRASG12C inhibitors. RESULTS: A total of 38 patients were included in this study: 27 with non-small-cell lung cancer, 10 with colorectal cancer, and 1 with appendiceal cancer. Putative mechanisms of resistance to adagrasib were detected in 17 patients (45% of the cohort), of whom 7 (18% of the cohort) had multiple coincident mechanisms. Acquired KRAS alterations included G12D/R/V/W, G13D, Q61H, R68S, H95D/Q/R, Y96C, and high-level amplification of the KRASG12C allele. Acquired bypass mechanisms of resistance included MET amplification; activating mutations in NRAS, BRAF, MAP2K1, and RET; oncogenic fusions involving ALK, RET, BRAF, RAF1, and FGFR3; and loss-of-function mutations in NF1 and PTEN. In two of nine patients with lung adenocarcinoma for whom paired tissue-biopsy samples were available, histologic transformation to squamous-cell carcinoma was observed without identification of any other resistance mechanisms. Using an in vitro deep mutational scanning screen, we systematically defined the landscape of KRAS mutations that confer resistance to KRASG12C inhibitors. CONCLUSIONS: Diverse genomic and histologic mechanisms impart resistance to covalent KRASG12C inhibitors, and new therapeutic strategies are required to delay and overcome this drug resistance in patients with cancer. (Funded by Mirati Therapeutics and others; ClinicalTrials.gov number, NCT03785249.).

Early phase studies of JAK1 selective inhibitors in rheumatoid arthritis.

The first approved Janus kinase (JAK) inhibitors for treatment of RA targeted more than one JAK molecule. Although this brings an advantage of simultaneous blocking of more cytokines involved in RA, it may also carry an increased risk of toxicity. Subsequently, more selective JAK inhibitors were developed with the aim of improving the safety-efficacy profile and to further increase drug maintenance. With this proposal, early phase trials of selective JAK1 inhibitors, namely upadacitinib, filgotinib and itacitinib, were initiated in recent years to identify the efficacy and adverse effects of these agents and to define their potential role in treatment of inflammatory and autoimmune diseases. Early phase (Phase I-II) studies of upadacitinib and filgotinib provided evidence for efficacy and safety of the selective JAK1 inhibitors in refractory populations of RA patients and allowed informed selection of the appropriate dose by balancing the optimal benefit-risk profile for further evaluation in the later successfully performed Phase III trials. Although itacitinib also demonstrated a good efficacy and safety in a Phase II trial in RA patients, it is mainly in development for haematologic and oncologic conditions.

Clinical Acquired Resistance to KRASG12C Inhibition through a Novel KRAS Switch-II Pocket Mutation and Polyclonal Alterations Converging on RAS-MAPK Reactivation.

Mutant-selective KRASG12C inhibitors, such as MRTX849 (adagrasib) and AMG 510 (sotorasib), have demonstrated efficacy in KRAS G12C-mutant cancers, including non-small cell lung cancer (NSCLC). However, mechanisms underlying clinical acquired resistance to KRASG12C inhibitors remain undetermined. To begin to define the mechanistic spectrum of acquired resistance, we describe a patient with KRAS G12C NSCLC who developed polyclonal acquired resistance to MRTX849 with the emergence of 10 heterogeneous resistance alterations in serial cell-free DNA spanning four genes (KRAS, NRAS, BRAF, MAP2K1), all of which converge to reactivate RAS-MAPK signaling. Notably, a novel KRAS Y96D mutation affecting the switch-II pocket, to which MRTX849 and other inactive-state inhibitors bind, was identified that interferes with key protein-drug interactions and confers resistance to these inhibitors in engineered and patient-derived KRAS G12C cancer models. Interestingly, a novel, functionally distinct tricomplex KRASG12C active-state inhibitor RM-018 retained the ability to bind and inhibit KRASG12C/Y96D and could overcome resistance. SIGNIFICANCE: In one of the first reports of clinical acquired resistance to KRASG12C inhibitors, our data suggest polyclonal RAS-MAPK reactivation as a central resistance mechanism. We also identify a novel KRAS switch-II pocket mutation that impairs binding and drives resistance to inactive-state inhibitors but is surmountable by a functionally distinct KRASG12C inhibitor.See related commentary by Pinnelli and Trusolino, p. 1874.This article is highlighted in the In This Issue feature, p. 1861.

Janus kinase inhibitors for atopic dermatitis: a promising treatment modality.

Atopic dermatitis (AD) is chronic, pruritic, inflammatory skin disease that affects a significant portion of the population in industrialized nations. For nonresponders to conventional therapies, AD can significantly reduce sleep quality and quality of life. AD pathogenesis is multifactorial and involves multiple immune pathways, with recent evidence of T helper (Th)2, Th17 and Th22 axis attenuation in various AD endotypes and racial subtypes. Inhibition of the conserved Janus kinase (JAK) signalling pathway represents a promising therapeutic avenue to reduce the activation of multiple proinflammatory mediators involved in AD pathogenesis. JAK inhibitors exist in both oral and topical forms with variable specificity for the receptor tyrosine kinases JAK1, JAK2, JAK3 and tyrosine kinase 2. Oral formulations include abrocitinib, upadacitinib, baricitinib and gusacitinib, and are most appropriate for patients with moderate to severe AD. Emerging topical formulation in development include ruxolitinib and deglocitinib, which may be used in patients with localized AD and also adjunctively with systemic therapy in patients with more severe disease. With observed rapidity in itch relief and accompanying dramatic reduction in inflammatory lesion count, JAK inhibitors represent a promising new treatment to revolutionize the management of AD.

The KRASG12C Inhibitor MRTX849 Provides Insight toward Therapeutic Susceptibility of KRAS-Mutant Cancers in Mouse Models and Patients.

Despite decades of research, efforts to directly target KRAS have been challenging. MRTX849 was identified as a potent, selective, and covalent KRASG12C inhibitor that exhibits favorable drug-like properties, selectively modifies mutant cysteine 12 in GDP-bound KRASG12C, and inhibits KRAS-dependent signaling. MRTX849 demonstrated pronounced tumor regression in 17 of 26 (65%) KRASG12C-positive cell line- and patient-derived xenograft models from multiple tumor types, and objective responses have been observed in patients with KRASG12C-positive lung and colon adenocarcinomas. Comprehensive pharmacodynamic and pharmacogenomic profiling in sensitive and partially resistant nonclinical models identified mechanisms implicated in limiting antitumor activity including KRAS nucleotide cycling and pathways that induce feedback reactivation and/or bypass KRAS dependence. These factors included activation of receptor tyrosine kinases (RTK), bypass of KRAS dependence, and genetic dysregulation of cell cycle. Combinations of MRTX849 with agents that target RTKs, mTOR, or cell cycle demonstrated enhanced response and marked tumor regression in several tumor models, including MRTX849-refractory models. SIGNIFICANCE: The discovery of MRTX849 provides a long-awaited opportunity to selectively target KRASG12C in patients. The in-depth characterization of MRTX849 activity, elucidation of response and resistance mechanisms, and identification of effective combinations provide new insight toward KRAS dependence and the rational development of this class of agents.See related commentary by Klempner and Hata, p. 20.This article is highlighted in the In This Issue feature, p. 1.

Oral Janus kinase/SYK inhibition (ASN002) suppresses inflammation and improves epidermal barrier markers in patients with atopic dermatitis.

BACKGROUND: Moderate-to-severe atopic dermatitis (AD) has been associated with significant disease burden and systemic abnormalities and often requires systemic treatments. Currently, safe and effective oral systemic treatments for moderate-to-severe AD are not yet available. ASN002 is an oral inhibitor of the Janus kinase/spleen tyrosine kinase signaling pathways, targeting several cytokine axes (TH2/TH22/TH17/TH1) and epidermal differentiation. OBJECTIVE: We sought to evaluate the effect of ASN002 on the cellular and molecular biomarker profile of patients with moderate-to-severe AD and to correlate changes in biomarkers to improvements in clinical severity measures and pruritus. METHODS: Thirty-six patients with moderate-to-severe AD were randomized to groups with dose escalation of ASN002 (20, 40, and 80 mg) and a placebo group. Skin biopsy specimens were performed at baseline, day 15, and day 29. Gene expression studies were conducted by using microarray and quantitative RT-PCR, and cellular infiltrates and protein expression were studied by using immunohistochemistry. RESULTS: ASN002 reversed the lesional skin transcriptome toward a nonlesional phenotype. It also rapidly and significantly suppressed key inflammatory pathways implicated in AD pathogenesis, including TH2 (IL4 receptor [IL4R], IL13, CCL13/monocyte chemoattractant protein 4, CCL17/thymus and activation-regulated chemokine, CCL18/pulmonary and activation-regulated chemokine, CCL22/macrophage-derived chemokine, and CCL26/eotaxin-3), TH17/TH22 (lipocalins, PI3/elafin, CCL20, S100A7/S100A8/S100A9, and IL36G/IL36RN), and TH1 (IFNG, CXCL9/CXCL11, and MX1) axes and barrier-related measures (filaggrin [FLG] and CLDN23). Significant improvements in AD gene signatures were observed predominantly in the 40- and 80-mg groups. Smaller and largely nonsignificant molecular changes were seen in the 20-mg and placebo groups. CONCLUSION: The Janus kinase/spleen tyrosine kinase inhibitor ASN002 significantly suppressed key AD inflammatory pathways, corresponding to clinical response. ASN002 might be an effective novel therapeutic agent for moderate-to-severe AD.

Anti-Tumorigenic and Anti-Metastatic Activity of the Sponge-Derived Marine Drugs Aeroplysinin-1 and Isofistularin-3 against Pheochromocytoma In Vitro.

Over 10% of pheochromocytoma and paraganglioma (PPGL) patients have malignant disease at their first presentation in the clinic. Development of malignancy and the underlying molecular pathways in PPGLs are poorly understood and efficient treatment strategies are missing. Marine sponges provide a natural source of promising anti-tumorigenic and anti-metastatic agents. We evaluate the anti-tumorigenic and anti-metastatic potential of Aeroplysinin-1 and Isofistularin-3, two secondary metabolites isolated from the marine sponge Aplysina aerophoba, on pheochromocytoma cells. Aeroplysinin-1 diminished the number of proliferating cells and reduced spheroid growth significantly. Beside these anti-tumorigenic activity, Aeroplysinin-1 decreased the migration ability of the cells significantly (p = 0.01), whereas, the invasion capacity was not affected. Aeroplysinin-1 diminished the high adhesion capacity of the MTT cells to collagen (p < 0.001) and, furthermore, reduced the ability to form spheroids significantly. Western Blot and qRT-PCR analysis showed a downregulation of integrin ß1 that might explain the lower adhesion and migration capacity after Aeroplysinin-1 treatment. Isofistularin-3 showed only a negligible influence on proliferative and pro-metastatic cell properties. These in vitro investigations show promise for the application of the sponge-derived marine drug, Aeroplysinin-1 as anti-tumorigenic and anti-metastatic agent against PPGLs for the first time.

Endogenous c-Jun N-terminal kinase (JNK) activity marks the boundary between normal and malignant granulosa cells.

Granulosa cell tumor of the ovary (GCT) is a very rare tumor, accounting for only 2% of all ovarian tumors. It originates from sex cords in the ovary and can be divided into adult (95%) and juvenile (5%) types based on histologic findings. To date, no clear etiologic process has been identified other than a missense point mutation in the FOXL2 gene. Our previous works showed that c-Jun N-terminal kinase (JNK) pathway plays critical role in cell cycle progression and mitosis of normal and immortalized granulosa cells and follicle growth in rodent ovaries. These findings led us to investigate the role of JNK pathway in the granulosa cell tumor of the ovary. We used two different GCT cell lines (COV434 and KGN) and fresh GCT samples of adult and juvenile types obtained from the patients during surgery. We have discovered that endogenous kinase activity of JNK is markedly enhanced in the GCT samples and cell lines, whereas it was almost undetectable in mitotic non-malignant human granulosa cells. The inhibition of JNK pathway in GCT cell lines with two different pharmacologic inhibitors (SP600125 and AS601245) or siRNA resulted in a dose-dependent reduction in in vitro cell growth, increased apoptosis and diminished estradiol and AMH productions. JNK inhibition was also associated with a decrease in the number of cells positive for mitosis marker phospho-histone H3Ser 10 in the asynchronous cells; and diminished EdU uptake during S phase and cell cycle arrest at G2/M-phase transition in the synchronized cells. Ex vivo treatment of patient-derived GCT samples with JNK inhibitors for 24 h significantly decreased their in vitro growth and estradiol and AMH productions. Furthermore, in human GCT xenograft model, in vivo tumor growth was significantly reduced and plasma AMH levels were significantly decreased in SCID mice after administration of JNK inhibitors and siRNA. These findings suggest that targeting JNK pathway may provide therapeutic benefit in the treatment of granulosa cell tumors for which currently no curative therapy exists beyond surgery.

Review of triazine antiprotozoal drugs used in veterinary medicine.

Triazines are relatively new antiprotozoal drugs that have successfully controlled coccidiosis and equine protozoal myeloencephalitis. These drugs have favorably treated other protozoal diseases such as neosporosis and toxoplasmosis. In this article, we discuss the pharmacological characteristics of five triazines, toltrazuril, ponazuril, clazuril, diclazuril, and nitromezuril which are used in veterinary medicine to control protozoal diseases which include coccidiosis, equine protozoal myeloencephalitis, neosporosis, and toxoplasmosis.

Simmondsin for weight loss in rats.

OBJECTIVE: To investigate the safety and efficacy for weight loss of simmondsin, a dietary supplement extracted from the seed of the jojoba plant (Simmondsia chinensis). ANIMALS: Sprague-Dawley male rats were fed various levels of simmondsin for 8 weeks (lean rats) or 16 weeks (high fat-induced obese rats). MEASUREMENTS: Food intake, body weight and composition, histopathology, hematology parameters. RESULTS: Simmondsin produced a clear dose-response effect on food intake and body weight. No remarkable histopathologic changes were noted in the liver, kidney and spleen. One lean animal, in the 0.5% group, had approximately a 20% depression in red bone marrow cells. Significant effects on hematology parameters were seen almost exclusively in groups consuming simmondsin at the highest level (0.5%) and these effects appeared to be reversed by removing simmondsin from the diet. CONCLUSION: Simmondsin at both the 0.15% level and the 0.25% level significantly reduced food intake and body weight without apparent negative effects. At dose levels much higher than therapeutic levels, there seemed to be reversible effects on circulating red and white blood cells. Future studies should determine long-term effects of lower doses on blood cell parameters.

Control of death receptor and mitochondrial-dependent apoptosis by c-Jun N-terminal kinase in hippocampal CA1 neurones following global transient ischaemia.

c-Jun N-terminal kinase (JNK), a member of the mitogen-activated protein kinase family, is activated in response to a number of extracellular stimuli, including inflammatory cytokines, UV irradiation and ischaemia. A large body of evidence supports a role for JNK signalling in stress-induced apoptosis. It has been hypothesized that JNK may contribute to the apoptotic response by regulating the intrinsic cell death pathway involving the mitochondria. Here, we examined the role of the JNK signalling pathway in hippocampal CA1 apoptotic neurones following transient ischaemia in gerbils. We showed early activation of death receptor-dependent apoptosis (caspase-8 activation 2 days after ischaemia) and a biphasic activation of caspase-3 and caspase-9 after ischaemia. Activation of the mitochondrial pathway, as measured by cytochrome c release, appeared as a late event (5-7 days after ischaemia). AS601245, a novel JNK inhibitor, antagonized activation of both pathways and significantly protected CA1 neurones from cell death. Our results suggest a key role of JNK in the control of death receptor and mitochondrial-dependent apoptosis after transient ischaemia.

Efficacy of selected coccidiostats in sandhill cranes (Grus canadensis) following challenge.

The anticoccidial efficacy of amprolium, clazuril, and monensin were studied in sandhill cranes (Grus canadensis) infected with a mixture of Eimeria spp. oocysts. Five groups of four 1-day-old sandhill crane chicks were maintained on a crumbled ration containing no coccidiostat, amprolium at 2.2 ppm, clazuril at 1.1 ppm, clazuril at 5.5 ppm, or monensin at 99 ppm. After 2 wk on their respective feeding regimens, birds in each of the five groups were administered 25 x 10(3) pooled sporulated Eimeria spp. oocysts per os and observed for another 3 wk. A sixth group of four chicks served as nonmedicated, nonchallenged control during the study. Clinical signs and lesions consistent with disseminated visceral coccidiosis were observed in all challenged controls and birds fed amprolium and clazuril. Birds in these groups died 9-10 days after challenge. In contrast, only one monensin-medicated bird had clinical signs of disseminated visceral coccidiosis, and it died 13 days after challenge (DAC). This and an asymptomatic bird that were necropsied at study termination had less-severe gross and microscopic lesions of disseminated visceral coccidiosis. Two of three monensin-treated birds that survived challenge passed from 50 to 500 coccidial oocysts 11 to 18 DAC but were negative at study termination. Of the coccidiostats tested, monensin, at the dietary level of 99 ppm, was the only anticoccidial drug that provided protection against experimentally induced disseminated visceral coccidiosis in sandhill cranes.

AS601245 (1,3-benzothiazol-2-yl (2-[[2-(3-pyridinyl) ethyl] amino]-4 pyrimidinyl) acetonitrile): a c-Jun NH2-terminal protein kinase inhibitor with neuroprotective properties.

Recent evidence suggests that activation of the c-Jun NH2-terminal protein kinase (JNK) signal transduction pathway may play a role in ischemia-induced cell death. Thus, preventing the activation of JNK, or c-Jun phosphorylation could be neuroprotective. In the current study, we report that a small molecule, AS601245 (1,3-benzothiazol-2-yl (2-[[2-(3-pyridinyl) ethyl] amino]-4 pyrimidinyl) acetonitrile), which has been shown to inhibit the JNK signaling pathway, promotes cell survival after cerebral ischemia. In vivo, AS601245 (40, 60, and 80 mg/kg) administered i.p. provided significant protection against the delayed loss of hippocampal CA1 neurons in a gerbil model of transient global ischemia. This effect is mediated by JNK inhibition and therefore by c-Jun expression and phosphorylation. A significant neuroprotective effect of AS601245 administered either by i.p. injection (6, 18, and 60 mg/kg) or as i.v. bolus (1 mg/kg) followed by an i.v. infusion (0.6 mg/kg/h) was also observed in rats after focal cerebral ischemia. These data suggest that the use of JNK inhibitors such as AS601245 may be a relevant strategy in the therapy of ischemic insults.