Abstract CT558: Capmatinib vs docetaxel as second- or third-line therapy in patients with locally advanced or metastatic METex14-mutated NSCLC: The GeoMETry-III trial

Background: MET dysregulation is a poor prognostic factor in advanced non-small cell lung cancer (NSCLC). MET exon 14 skipping (METex14) mutations occur in ~3% of patients with NSCLC. There is limited evidence of the efficacy of standard therapies, such as chemotherapy or immunotherapy, in patients with METex14-mutated advanced NSCLC. Capmatinib, a MET inhibitor (METi), is approved for the treatment of adult patients with metastatic METex14-mutated NSCLC, based on the results of the phase 2 GEOMETRY mono-1 study. Results (data cutoff: September 18, 2020) of this study in patients with METex14-mutated NSCLC treated with capmatinib showed an overall response rate (ORR) of 66.7% in first line (N=60), 51.6% in second line (N=31) and 40.6% in second- or third-line (2/3L; N=69). GeoMETry-III (NCT04427072) is a multicenter, open-label, randomized, controlled, global, phase 3 trial that is further evaluating the efficacy and safety of capmatinib vs docetaxel in the 2/3L setting in patients with METex14-mutated NSCLC.

Methods: This study began enrollment in September 2020 and is currently recruiting adult patients with EGFR wild-type, ALK-negative, stage IIIB/IIIC/IV METex14-mutated NSCLC, who have progressed on 1 or 2 prior lines of systemic therapy for advanced/metastatic disease and are candidates for single-agent docetaxel. Other eligibility criteria include ≥1 measurable lesion per the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1), an Eastern Cooperative Oncology Group performance status of ≤1 and no prior treatment with any METi or hepatocyte growth factor-targeting therapies. Patients with neurologically unstable, symptomatic central nervous system (CNS) metastases or those requiring increasing doses of steroids ≤2 weeks prior to study entry to manage CNS symptoms are excluded. Around 90 patients will be randomized 2:1 to receive either oral capmatinib 400 mg twice daily or intravenous docetaxel 75 mg/m2 every 21 days. Randomization is stratified by number of prior lines (1 or 2) of systemic therapy. Patients meeting protocol-specified eligibility criteria can cross over from the docetaxel to the capmatinib arm after blinded independent review committee (BIRC)-confirmed progressive disease as per RECIST 1.1.The primary endpoint is progression-free survival (PFS) by BIRC per RECIST 1.1. The key secondary endpoint is ORR by BIRC per RECIST 1.1. Other secondary endpoints include investigator-assessed ORR and PFS; duration of response, time to response and disease control rate (DCR) by BIRC and investigator; overall survival; safety; pharmacokinetics; patient-reported outcomes; overall intracranial response rate, intracranial DCR, duration of- and time to- intracranial response by BIRC per the Response Assessment in Neuro-Oncology Brain Metastases criteria in patients with baseline CNS lesions.

Citation Format: Pierre Jean Souquet, Sang-We Kim, Johan F. Vansteenkiste, Anna Robeva, Aline Jary, Sabine Glaser, Alejandro Yovine, Juergen Wolf. Capmatinib vs docetaxel as second- or third-line therapy in patients with locally advanced or metastatic METex14-mutated NSCLC: The GeoMETry-III trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT558.

Capmatinib in MET exon 14-mutated, advanced NSCLC: Updated results from the GEOMETRY mono-1 study

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Background: Capmatinib, a selective MET inhibitor, is approved in the USA and Japan for the treatment of patients (pts) with MET exon 14 skipping mutation ( METex14) advanced non-small-cell lung cancer (NSCLC) based on the multi-cohort phase II GEOMETRY mono-1 study. This is the first report on expansion Cohort 7 in first line (1L) METex14 NSCLC pts, with updates to previously reported results (Wolf et al, NEJM 2020) for METex14 pts. Methods: In GEOMETRY mono-1, pts were assigned to cohorts based on previous lines of therapy and MET status ( METex14 or MET amplification). This efficacy analysis includes patients with METex14 NSCLC who were treatment-naive (Cohort 5b and 7) and those who had previously received 1L or 2L of therapy (expansion Cohort 6 and Cohort 4) for their advanced disease (data cutoff: Sep 18, 2020). Evaluated outcomes included overall response rate (ORR), duration of response (DOR), and progression-free survival (PFS), all by BIRC; and overall survival (OS). The safety analysis includes all patients enrolled. Results: In total, 160 pts with METex14 who received capmatinib 400 mg BID were analyzed. ORR of 65.6% (95% CI 46.8-81.4) for the treatment-naive expansion Cohort 7 was in line with that previously reported for Cohort 5b (Table). Though Cohort 7 data are still immature, median PFS was 10.8 mo (95% CI 6.87-not estimable [NE]). Mature median OS was 20.8 mo (95% CI 12.4-NE) in Cohort 5b and 13.6 mo (95% CI 8.6-22.2) in Cohort 4. Median OS for Cohorts 6 and 7 and DOR for Cohort 7 are not yet reached. The safety profile remained unchanged across all study cohorts (N = 373): 98.4% of pts reported AEs (68.6% Grade [G] 3/4) regardless of causality and 16.1% reported AEs leading to discontinuation (10.5% G3/4). The most common AEs (≥20% all G) were peripheral edema (54.2%), nausea (45.0%), vomiting (28.2%), increased blood creatinine (26.5%), dyspnea (23.3%), fatigue (22.3%), and decreased appetite (21.2%). Conclusions: Results of Cohort 7 confirm those previously reported for Cohort 5b showing higher efficacy of capmatinib when used as 1L in METex14 NSCLC pts. A clinically meaningful median OS of 20.8 mo in 1L (Cohort 5b) and of 13.6 mo in relapse (Cohort 4) was also observed and, together with the continued manageable toxicity profile, the data support capmatinib as a valuable targeted treatment option for METex14 NSCLC pts. Clinical trial information: NCT02414139. [Table: see text]

Capmatinib in MET Exon 14-Mutated or MET-Amplified Non-Small-Cell Lung Cancer

BACKGROUND

Among patients with non-small-cell lung cancer (NSCLC), MET exon 14 skipping mutations occur in 3 to 4% and MET amplifications occur in 1 to 6%. Capmatinib, a selective inhibitor of the MET receptor, has shown activity in cancer models with various types of MET activation.

METHODS

We conducted a multiple-cohort, phase 2 study evaluating capmatinib in patients with MET-dysregulated advanced NSCLC. Patients were assigned to cohorts on the basis of previous lines of therapy and MET status (MET exon 14 skipping mutation or MET amplification according to gene copy number in tumor tissue). Patients received capmatinib (400-mg tablet) twice daily. The primary end point was overall response (complete or partial response), and the key secondary end point was response duration; both end points were assessed by an independent review committee whose members were unaware of the cohort assignments.

RESULTS

A total of 364 patients were assigned to the cohorts. Among patients with NSCLC with a MET exon 14 skipping mutation, overall response was observed in 41% (95% confidence interval [CI], 29 to 53) of 69 patients who had received one or two lines of therapy previously and in 68% (95% CI, 48 to 84) of 28 patients who had not received treatment previously; the median duration of response was 9.7 months (95% CI, 5.6 to 13.0) and 12.6 months (95% CI, 5.6 to could not be estimated), respectively. Limited efficacy was observed in previously treated patients with MET amplification who had a gene copy number of less than 10 (overall response in 7 to 12% of patients). Among patients with MET amplification and a gene copy number of 10 or higher, overall response was observed in 29% (95% CI, 19 to 41) of previously treated patients and in 40% (95% CI, 16 to 68) of those who had not received treatment previously. The most frequently reported adverse events were peripheral edema (in 51%) and nausea (in 45%); these events were mostly of grade 1 or 2.

CONCLUSIONS

Capmatinib showed substantial antitumor activity in patients with advanced NSCLC with a MET exon 14 skipping mutation, particularly in those not treated previously. The efficacy in MET-amplified advanced NSCLC was higher in tumors with a high gene copy number than in those with a low gene copy number. Low-grade peripheral edema and nausea were the main toxic effects. (Funded by Novartis Pharmaceuticals; GEOMETRY mono-1 ClinicalTrials.gov number, NCT02414139.).

Abstract CT082: Capmatinib in METex14-mutated (mut) advanced non-small cell lung cancer (NSCLC): Results from the phase II GEOMETRY mono-1 study, including efficacy in patients (pts) with brain metastases (BM)

Background: Capmatinib is a highly selective and potent MET inhibitor that crosses the blood-brain barrier. In the GEOMETRY mono-1 study, capmatinib showed clinically meaningful response rates in pts with advanced NSCLC harboring METex14 skipping mutations, including activity in pts with baseline BM, and also demonstrated manageable safety. Here, we present efficacy and safety data, including an efficacy analysis in METex14 skipping mutated NSCLC pts with baseline BM. Methods: The phase 2, multi-cohort, multicenter GEOMETRY mono-1 study (NCT02414139) is evaluating capmatinib in adult pts with ECOG PS 0-1, ALK and EGFR-wt, METex14-mut/MET-amplified stage IIIB/IV NSCLC, including pts with neurologically stable/asymptomatic BM. Pts were assigned to Cohorts 4 (pretreated, 2/3L) and 5b (treatment-naive) and received capmatinib 400 mg BID. Primary endpoint: overall response rate (ORR) by BIRC per RECIST v1.1. Key secondary endpoint: duration of response (DOR) by BIRC. The retrospective analyses on brain lesions were based on modified RECIST v1.1 as assessed by BIRC neuro-radiologic assessments of all Cohorts 4 and 5b pts with baseline BM. Results: As of April 15, 2019, 97 pts (Cohort 4: 69 pts; Cohort 5b: 28 pts) were evaluable for efficacy. BIRC results for cohorts 4 and 5b, respectively, were (i) ORR (95%CI): 40.6% (28.9-53.1) and 67.9% (47.6-84.1), (ii) median DOR (95%CI): 9.72 (5.55-12.98) and 11.14 (5.55-NE) months (mos), and (iii) median progression-free survival (95%CI): 5.42 (4.17-6.97) and 9.69 (5.52-13.86) mos. There were 13 pts with evaluable baseline BM by BIRC [3.3 brain lesions/pt (range 1−8)]. 7 of the 13 pts (54%) had intracranial response of which 4 pts had complete resolution of all brain lesions. The other 3 responders had (i) complete resolution in 3 lesions, −50% reduction in 1 lesion, stabilization in remaining 4 lesions (total 7 lesions), (ii) complete resolution in 2 lesions, stabilization in 1 remaining lesion (total 3 lesions), and (iii) complete resolution in 1 lesion, stabilization in 3 remaining lesions (total 4 lesions). Intracranial disease control was achieved in 12/13 pts. Intracranial responses were as fast as systemic responses. 3/7 responders had prior brain radiotherapy; 5/7 responders had either signs of progression in the existing brain lesion(s) or new BM at study entry. Most common tx-related adverse events (≥15%, all grades) across all cohorts (N=334) were peripheral edema (41.6%), nausea (33.2%), increased blood creatinine (19.5%), and vomiting (18.9%). Conclusion: BIRC neuro-radiologist review of 13 pts with evaluable baseline BM suggested that capmatinib has anti-tumor efficacy in the brain. Capmatinib also showed deep and durable responses in pts with METex14-mut advanced NSCLC regardless of line of therapy and demonstrated a manageable safety profile.

Citation Format: Edward B. Garon, Rebecca S. Heist, Takashi Seto, Ji-Youn Han, Noemi Reguart, Harry J. Groen, Daniel SW Tan, Toyoaki Hida, Maja J. de Jonge, Sergey V. Orlov, Egbert F. Smit, Pierre-Jean Souquet, Johan Vansteenkiste, Sylvie Le Mouhaer, Anna Robeva, Maeve Waldron-Lynch, Monica Giovannini, Juergen Wolf. Capmatinib in METex14-mutated (mut) advanced non-small cell lung cancer (NSCLC): Results from the phase II GEOMETRY mono-1 study, including efficacy in patients (pts) with brain metastases (BM) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT082.

Capmatinib (INC280) in METΔex14-mutated advanced non-small cell lung cancer (NSCLC): Efficacy data from the phase II GEOMETRY mono-1 study

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Background: Capmatinib is a highly potent and selective MET inhibitor. Previous data of GEOMETRY mono-1 study showed a clinically meaningful overall response rate (ORR) and manageable toxicity profile in patients (pts) with METΔex14–mutated NSCLC who received 1–2 prior lines of treatment (tx) (Cohort 4) and in particular a high ORR in tx-naïve pts (Cohort 5b). Here we report the results in METΔex14–mutated NSCLC for duration of response (DOR) and progression-free survival (PFS) as well as the updated results for ORR. Methods: GEOMETRY mono-1 is a phase 2, multi-cohort, multicenter study evaluating capmatinib in pts with METΔex14-mutated or MET-amplified advanced NSCLC across 6 cohorts. Pts (≥18 yrs) with ECOG PS 0–1, ALK and EGFR wt, and stage IIIB/IV NSCLC were eligible. Pts with METΔex14 mutation (centrally confirmed) were assigned (regardless of MET amplification status/gene copy number) to Cohorts 4 and 5b and received capmatinib tablets 400 mg BID. Primary endpoint was ORR by Blinded Independent Review Committee (BIRC) per RECIST v1.1. Key secondary endpoint was DOR by BIRC. Results: As of Nov 08, 2018, 97 pts with METΔex14-mutated NSCLC (Cohort 4: 69 pts; Cohort 5b: 28 pts) were evaluable for efficacy. ORR (95% CI) by BIRC was 39.1% (27.6-51.6) in Cohort 4 and 71.4% (51.3-86.8) in Cohort 5b. While still immature at the time of this analysis, data on durability are promising: median DOR (95% CI) by BIRC was 9.72 (4.27-11.14) and 8.41 (5.55-NE) mo for Cohorts 4 and 5b, respectively; median PFS (95% CI) by BIRC was 5.42 (4.17-6.97) and 9.13 (5.52-13.86) mo for Cohorts 4 and 5b, respectively. Safety profile remains favourable and unchanged. Most common AEs (≥25% all grades) across all cohorts (n = 315), were peripheral edema (49.2%), nausea (43.2%), and vomiting (28.3%); majority of the AEs were grade 1/2. Final efficacy analysis (12-mo f-u on DOR) including biomarker data will be presented during meeting. Conclusions: These data confirm capmatinib to be a promising new treatment option for pts with METΔex14-mutated advanced NSCLC regardless of the line of therapy with deep and durable responses and manageable toxicity profile. Clinical trial information: NCT02414139.

Everolimus for patients with mantle cell lymphoma refractory to or intolerant of bortezomib: multicentre, single-arm, phase 2 study

The multicentre, open-label, two-stage, single-arm, phase 2, PILLAR (PIvotaL Lymphoma triAls of RAD001)-1 study (NCT00702052) assessed the efficacy and safety of everolimus 10 mg/d in adults with confirmed mantle cell lymphoma (MCL) refractory to or intolerant of bortezomib who received ≥1 other antineoplastic agent, either separately or in combination with bortezomib. Primary endpoint was overall response rate (ORR) per investigator review according to the response criteria for malignant lymphoma. Secondary endpoints included progression-free survival (PFS), overall survival (OS) and safety. Fifty-eight patients were enrolled from August 2008-January 2011. Five partial responses were observed (ORR 8·6%; 90% confidence interval [CI] 3·5-17·3%); the study did not meet the prespecified objective of ≥8 objective responses among 57 patients. Median PFS and OS were 4·4 months (95% CI 3·5-6·1) and 16·9 months (95% CI 14·4-29·9), respectively. Grade 3/4 non-haematological toxicities occurred in 70·7% of patients. Based on laboratory values, grade 3/4 thrombocytopenia, neutropenia and anaemia occurred in 13·8%, 13·8% and 8·6% of patients, respectively. Everolimus demonstrated modest activity and acceptable tolerability in heavily pretreated patients with MCL refractory to or intolerant of bortezomib. Future studies evaluating everolimus in a less refractory population or in combination with other targeted therapies in refractory MCL are warranted.

Mutational uncoupling of alpha1A-adrenergic receptors from G proteins also uncouples mitogenic and transcriptional responses in PC12 cells

Activation of human alpha1A-adrenergic receptors in PC12 cells causes many second messenger, mitogenic, and transcriptional responses. We examined the role of G protein activation in these responses by uncoupling the receptor through deletion of the first three amino acids from the third intracellular loop (Delta208-210). Expression levels of retrovirus-transfected wild-type and Delta(208-210) alpha1A-adrenergic receptors in PC12 cells were similar and showed identical binding affinities for antagonists. However, the potency of the agonist norepinephrine was increased 9-fold by the Delta (208-210) mutation. In PC12 cells expressing the Delta (208-210) construct, calcium and inositol phosphate responses to norepinephrine were essentially abolished. The strong activation of mitogen-activated protein kinase pathways seen upon stimulation of wild-type alpha1A-adrenergic receptors in PC12 cells was abolished by the Delta (208-210) mutation, as was activation of the tyrosine kinase Pyk2. Norepinephrine also activates several transcriptional reporters through alpha1A-adrenergic receptors in PC12 cells, including reporters for activator protein 1, serum response element, cAMP response element, nuclear factor-kappaB, nuclear factor of activated T cells, gamma-interferon-activated sequence, and signal transducer and activator of transcription. All these transcriptional responses were abolished by the Delta (208-210) mutation. Overexpression of Galpha16 did not rescue any of these responses. These data suggest that known second messenger, mitogenic, and transcriptional effects of alpha1A-adrenergic receptors in PC12 cells all require G protein activation.

Nogo-A inhibits neurite outgrowth and cell spreading with three discrete regions

Nogo-A is a potent neurite growth inhibitor in vitro and plays a role both in the restriction of axonal regeneration after injury and in structural plasticity in the CNS of higher vertebrates. The regions that mediate inhibition and the topology of the molecule in the plasma membrane have to be defined. Here we demonstrate the presence of three different active sites: (1) an N-terminal region involved in the inhibition of fibroblast spreading, (2) a stretch encoded by the Nogo-A-specific exon that restricts neurite outgrowth and cell spreading and induces growth cone collapse, and (3) a C-terminal region (Nogo-66) with growth cone collapsing function. We show that Nogo-A-specific active fragments bind to the cell surface of responsive cells and to rat brain cortical membranes, suggesting the existence of specific binding partners or receptors. Several antibodies against different epitopes on the Nogo-A-specific part of the protein as well as antisera against the 66 aa loop in the C-terminus stain the cell surface of living cultured oligodendrocytes. Nogo-A is also labeled by nonmembrane-permeable biotin derivatives applied to living oligodendrocyte cultures. Immunofluorescent staining of intracellular, endoplasmic reticulum-associated Nogo-A in cells after selective permeabilization of the plasma membrane reveals that the epitopes of Nogo-A, shown to be accessible at the cell surface, are exposed to the cytoplasm. This suggests that Nogo-A could have a second membrane topology. The two proposed topological variants may have different intracellular as well as extracellular functions.

Biochemistry and pharmacology of epitope-tagged alpha(1)-adrenergic receptor subtypes

Human alpha(1A)-, alpha(1B)-, and alpha(1D)-adrenergic receptors were tagged at their amino termini with FLAG epitopes and stably expressed in human embryonic kidney (HEK)293 cells. Tagged receptors demonstrated a wild-type pharmacology and mobilization of intracellular Ca(2+). After solubilization and immunoprecipitation, monomers, dimers, and trimers of each subtype were apparent on Western blots. Further denaturation with 6 M urea reduced most oligomers to monomers. Deglycosylation reduced the molecular size of alpha(1A)-, and to a lesser extent alpha(1B)- and alpha(1D)-adrenergic receptors. Radioligand binding site density was highest for alpha(1A)- and much lower for alpha(1B)- and alpha(1D)-adrenergic receptors, but did not correlate with protein expression. Commercial anti-alpha(1)-adrenergic receptor antibodies did not recognize the tagged receptors in Western blots of cell lysates, and substantial cross-reactivity was still observed after solubilization and immunoprecipitation. Surprisingly, only receptor monomers were apparent after photoaffinity labeling with (125)I-arylazidoprazosin, and the intensity of photoaffinity-labeling correlated with the density of radioligand binding sites. We conclude that epitope-tagged alpha(1)-adrenergic receptors exist as both monomers and oligomers in HEK293 cells, but there is substantial discrepancy between protein and binding site expression. Because only monomers are detected by photoaffinity labeling, dimers and trimers observed on Western blots may be pharmacologically inactive.

Inhibition of contact hypersensitivity reaction to picryl chloride: effect of small molecular weight peptidomimetic compounds possessing inhibitory activity against metalloproteinases

We have studied the effect of small molecular weight inhibitors of snake venom metalloproteinases (SVMP) and matrix metalloproteinases (MMPs) on the induction and effector phase of the contact hypersensitivity reaction (CHR) in a mouse model. Identification of nonsteroid small molecules is very important for the development of new anti-inflammatory drugs. The compounds that we tested were synthetically modified tripeptides (peptidomimetic compounds) POL-257, POL-509, POL-443, POL-491, and POL-647, with structures based on natural occurring peptides in snake venom. A well-known hydroxamate-based inhibitor of the MMPs, Batimastat (BB-94), was also used. We have shown that these peptidomimetics possess in vitro inhibitory activity against the MMP-2 (gelatinase-A), MMP-9 (gelatinase-B), and MMP-3 (stromelysin). They also inhibit metalloproteinases purified from the venom of Crotalus adamanteus and C. atrox snakes, which are very similar to the so-called A Desintegrine, A Metalloproteinase (ADAMs) enzymes. When injected intraperitonealy before the topical application of the contact sensitizer (picryl chloride) or before the challenge, these compounds significantly inhibited the development of CHR. BB-94 at doses 0.4 and 4 mg/kg before the sensitization or before the challenge almost completely abrogated the reaction. POL-257 and POL-443 were among the most active peptidomimetics tested. They inhibited the inflammatory reaction up to 70-80%, when applied either immediately before sensitization or before challenge. POL-509, a methylated derivative of POL-257, inhibited the CHR to 40-50% when administered at either challenge or sensitization. However, when applied 24 h before the challenge, it completely abrogated the inflammatory reaction. The results show that these small molecular weight peptidomimetic compounds, as well as BB-94, are able to significantly inhibit the CHR. This finding opens possibilities for using metalloproteinase inhibitors in the treatment of allergic contact dermatitis and other inflammatory diseases.

Signaling pathways activated by alpha1-adrenergic receptor subtypes in PC12 cells

PC12 cells were used to compare signaling pathways activated by alpha1-adrenergic receptor (AR) subtypes. PC12 cells were transfected with human alpha1A, alpha1B, or alpha1D-ARs, and subclones stably expressing receptor densities in physiological ranges isolated and characterized. Norepinephrine (NE) activated a large number of signaling pathways in transfected cells, including inositol phosphate formation, intracellular calcium, all three arms of the mitogen activated protein kinase pathways, and a number of tyrosine kinases. Activation of mitogen activated protein kinase pathways and tyrosine kinases was not blocked by chelation of intracellular calcium with BAPTA or inhibition of protein kinase C. NE also activated luciferase reporter constructs for seven different transcription factors (AP1, SRE, CRE, NFkappaB, NFAT, Stat, GAS) following transfection into alpha1A-AR expressing PC12 cells. However, similar increases in inositol phosphate formation and intracellular Ca2+ caused by purinergic P2Y2 receptor activation did not activate any of these reporters. Comparison of alpha1-AR subtypes showed that the alpha1A activated all seven reporters, the alpha1B showed smaller effects, while the alpha1D was ineffective. NE caused differentiation of alpha1A, but not alpha1B or alpha1D, -AR expressing PC12 cells similar to that caused by NGF. This NE-induced differentiation was reduced or blocked by all inhibitors tested. We conclude that alpha1-ARs activate many signaling pathways and transcriptional responses in PC12 cells, which are not linearly related to second messenger production, and which may differ for different alpha1-AR subtypes.

Serum amyloid A (apoSAA) expression is up-regulated in rheumatoid arthritis and induces transcription of matrix metalloproteinases

The acute-phase reactant rabbit serum amyloid A 3 (SAA3) was identified as the major difference product in Ag-induced arthritis in the rabbit, a model resembling in many aspects the clinical characteristics of rheumatoid arthritis (RA) in humans. In Ag-induced arthritis, up-regulated SAA3 transcription in vivo was detected in cells infiltrating into the inflamed joint, in the area where pannus formation starts and, most notably, also in chondrocytes. The proinflammatory cytokine IL-1beta induced SAA3 transcription in primary rabbit chondrocytes in vitro. Furthermore, rSAA3 protein induced transcription of matrix metalloproteinases in rabbit chondrocytes in vitro. In the human experimental system, IL-1beta induced transcription of acute-phase SAA (A-SSA; encoded by SAA1/SAA2) in primary chondrocytes. Similar to the rabbit system, recombinant human A-SAA protein was able to induce matrix metalloproteinases' transcription in chondrocytes. Further, immunohistochemistry demonstrated that A-SAA was highly expressed in human RA synovium. A new finding of our study is that A-SSA expression was also detected in cartilage in osteoarthritis. Our data, together with previous findings of SAA expression in RA synovium, suggest that A-SAA may play a role in cartilage destruction in arthritis.

Immunohistochemical localization of adenosine A2A receptors in the rat central nervous system

The A2A adenosine receptor (A2A-AR) transcript and radioligand binding sites have a distinct distribution in rat brain, restricted primarily to the striatum, nucleus accumbens and olfactory tubercles. We describe here the use of purified recombinant human A2A-ARs to generate a monoclonal antibody that has been used to better resolve the distribution of A2A-ARs in rat brain. The antibody can detect 1 ng of purified recombinant receptor by Western blotting and is potent (EC50 = 0.62 microg/ml) and highly selective for the A2A-AR subtype. By Western blotting, the apparent molecular mass of recombinant and rat striatal receptors shifts upon deglycosylation from 43-48 to 42 kilodaltons. Analyses of chimeric A1/A2A-ARs and synthesis of a blocking peptide pinpointed the epitope (SQPLPGER) of the antibody to the center of the third intracellular loop of the receptor. Incubation of rat striatal membranes with antibody reduces receptor coupling to G-proteins. In rat brain, dense A2A-AR-like immunoreactivity that is eliminated by the blocking peptide was found in the neuropil of the striatum, nucleus accumbens (rostral pole, core and shell), cell bridges of the striatum, olfactory tubercles, and areas of extended amygdala with somewhat lighter labeling in the globus pallidus and nucleus of the solitary tract. Light perikaryal labeling was found in other areas of the brain, including the cortex, hippocampus, thalamus, cerebellum, and portions of the hindbrain. The observed distribution of A2A-AR immunoreactivity throughout the neuraxis is consistent with the receptors' role in modulating dopaminergic neurotransmission and central control of cardiovascular function.

Beta-adrenoceptor activity change after prolonged treatment with growth hormone and somatostatin

1. The effect of 10 days treatment with growth hormone (GH) (1 mg/kg body wt/day) and somatostatin (SRIF) (0.25 mg/kg body wt/day) subcutaneously on the activity of beta-adrenoceptors in rat hypothalamic, pituitary and cerebral cortical membrane fractions was studied using [3H]dihydroalprenolol ([3H]DHA) as radioligand. 2. The administration of GH significantly increased the beta-adrenoceptor binding affinity and the administration of SRIF decreased the beta-adrenoceptor binding capacity in the hypothalamus. 3. In the pituitary the beta-adrenoceptor binding affinity was significantly decreased after both hormonal applications. 4. In the cerebral cortex the beta-adrenoceptor binding affinity was significantly decreased after the GH treatment and increased after the SRIF treatment. 5. The present study provides direct evidence for GH and SRIF effects on the activity of rat beta-adrenoceptors and supports the view about the involvement of beta-adrenergic mechanisms in the neurotransmitter regulation of GH secretion in the rat.

Muscarinic receptor activity change after prolonged treatment with growth hormone and somatostatin

1. The effect of 10-day treatment with growth hormone (GH) (1 mg/kg body weight day) and somatostatin (SRIF) (0.25 mg/kg body weight day) subcutaneously on the activity of muscarinic (M) receptors in rat hypothalamic, pituitary and cerebral cortical membrane fractions was studied using (3H)quinuclidinyl benzylate [(3H)QNB] as radioligand. 2. The administration of GH and SRIF significantly decreased the M-receptor binding affinity in the hypothalamus. 3. In the pituitary the M-receptor affinity was increased after both GH and SRIF treatment. 4. In the hypothalamus and the pituitary the binding capacity of muscarinic receptors was unchanged. 5. In the cerebral cortex the chronical GH injection induced an increase in the number of antagonist binding sites and a decrease of their affinity, while the similar SRIF treatment led to an increase of the binding affinity without any change of M-receptor capacity. 6. These results indicate that GH and SRIF selectively and region-specifically modulate muscarinic receptor binding affinity and capacity and provide new insight into the feedback regulatory mechanisms of GH secretion.