Phase II study of eribulin in combination with gemcitabine for the treatment of patients with locally advanced or metastatic triple negative breast cancer (ERIGE trial). Clinical and pharmacogenetic results on behalf of the Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC).

BACKGROUND: The combination of a microtubule inhibitor (eribulin) with a nucleoside analog (gemcitabine) may synergistically induce tumor cell death, particularly in triple negative breast cancer (TNBC) characterized by high cell proliferation, aggressive behavior, and chemo-resistance. PATIENTS AND METHODS: This is an open-label, multicenter phase II study evaluating the combination of eribulin (0.88 mg/m2) plus gemcitabine (1000 mg/m2) on days 1 and 8 of a 21-day cycle as either first- or second-line treatment of locally advanced or metastatic TNBC. The primary endpoint was the objective response for evaluable patients. A prospective, molecular correlative study was carried out to assess the role of germinal BRCA pathogenic variants and single nucleotide polymorphisms (SNPs) in predicting efficacy and toxicity of the combination regimen. RESULTS: From July 2013 to September 2016, 83 evaluable patients were enrolled. They received a median number of six cycles of treatment. An overall response rate (ORR) of 37.3% (31 patients) was observed, with a complete response rate of 2.4% and a partial response rate of 34.9%; the clinical benefit rate was 48.8%. With a median follow-up of 28.8 months, the median response duration was 6.6 months, the median progression-free survival (PFS) was 5.1 months, and the median overall survival (OS) was 14.5 months. The most common grade 3-4 adverse events were aminotransferase elevation (in 25% of the patients) and neutropenia (in 23.8%). Women with BRCA1/2 pathogenic variants were associated with worse ORR, PFS, and OS than BRCA1/2 wild-type carriers. CYP3A4 and FGD4 SNPs were associated with increased risk of liver toxicity. Three different SNPs in CDA∗2, RRM1, and CYP2C8 genes were significantly associated with poorer OS. CONCLUSIONS: The combination of eribulin and gemcitabine showed promising activity and a moderate toxicity profile in metastatic TNBC. BRCA status and pharmacogenetics tests may help identify patients with high probability of response with negligible toxicity. EUDRACT NUMBER: 2012-003505-10.

Ethanol elicits and potentiates nociceptor responses via the vanilloid receptor-1.

The vanilloid receptor-1 (VR1) is a heat-gated ion channel that is responsible for the burning sensation elicited by capsaicin. A similar sensation is reported by patients with esophagitis when they consume alcoholic beverages or are administered alcohol by injection as a medical treatment. We report here that ethanol activates primary sensory neurons, resulting in neuropeptide release or plasma extravasation in the esophagus, spinal cord or skin. Sensory neurons from trigeminal or dorsal root ganglia as well as VR1-expressing HEK293 cells responded to ethanol in a concentration-dependent and capsazepine-sensitive fashion. Ethanol potentiated the response of VR1 to capsaicin, protons and heat and lowered the threshold for heat activation of VR1 from approximately 42 degrees C to approximately 34 degrees C. This provides a likely mechanistic explanation for the ethanol-induced sensory responses that occur at body temperature and for the sensitivity of inflamed tissues to ethanol, such as might be found in esophagitis, neuralgia or wounds.

Expression and function of proteinase-activated receptor 2 in human bronchial smooth muscle.

Trypsin and mast cell tryptase cleave proteinase-activated receptor 2 (PAR2) to induce alterations in contraction of airway smooth muscle that have been implicated in asthma in experimental animals. Although tryptase inhibitors are under development for treatment of asthma, little is known about the localization and function of PAR2 in human airways. We detected PAR2 expression in primary cultures of human airway smooth muscle cells using reverse transcriptase/polymerase chain reaction (RT-PCR) and immunofluorescence. The PAR2 agonists trypsin, tryptase, and an activating peptide (SLIGKV-NH2) stimulated calcium mobilization in these cells. PAR2 agonists strongly desensitized responses to a second challenge of trypsin and SLIGKV-NH2, but not to thrombin, indicating that they activate a receptor distinct from the thrombin receptors. Immunoreactive PAR2 was detected in smooth muscle, epithelium, glands, and endothelium of human bronchi. Trypsin, SLIGKV-NH2, and tryptase stimulated contraction of isolated human bronchi. Contraction was increased by removal of the epithelium and diminished by indomethacin. Thus, PAR2 is expressed by human bronchial smooth muscle where its activation mobilizes intracellular Ca2+ and induces contraction. These results are consistent with the hypothesis that PAR2 agonists, including tryptase, induce bronchoconstriction of human airway by stimulating smooth muscle contraction. PAR2 antagonists may be useful drugs to prevent bronchoconstriction.

The vanilloid receptor (VR1)-mediated effects of anandamide are potently enhanced by the cAMP-dependent protein kinase.

The endogenous cannabinoid receptor ligand, anandamide (AEA), is a full agonist of the vanilloid receptor type 1 (VR1) for capsaicin. Here, we demonstrate that the potency and efficacy of AEA at VR1 receptors can be significantly increased by the concomitant activation of protein kinase A (PKA). In human embryonic kidney (HEK) cells over-expressing human VR1, AEA induces a rise in cytosolic Ca(2+) concentration that is mediated by this receptor. The EC(50) for this effect was decreased five-fold in the presence of forskolin (FRSK, 1-5 microM) or the cAMP analogue, 8-Br-cAMP (10-100 microM). The effects of 8-Br-cAMP and FRSK were blocked by a selective PKA inhibitor. The FRSK (10 nM) also potently enhanced the sensory neurone- and VR1-mediated constriction by AEA of isolated guinea-pig bronchi, and this effect was abolished by a PKA inhibitor. In rat dorsal root ganglia slices, AEA-induced release of substance P, an effect mediated by VR1 activation, was enhanced three-fold by FRSK (10 nM). Thus, the ability of AEA to stimulate sensory VR1, with subsequent neuropeptide release, appears to be regulated by the state of activation of PKA. This observation supports the hypothesis that endogenous AEA might stimulate VR1 under certain pathophysiological conditions.

Role of peripheral N-methyl-D-aspartate (NMDA) receptors in visceral nociception in rats.

BACKGROUND & AIMS: N-methyl-D-aspartate (NMDA) receptors are ligand-gated ion channels that have an important role in long-term potentiation and memory processing in the central nervous system. The aims in this study were to determine whether NMDA receptors are expressed in the peripheral nervous system and identify their role in mediating behavioral pain responses to colonic distention in the normal gut. METHODS AND RESULTS: Immunohistochemical localization of the NR1 subunit showed that NMDA receptors are expressed on the cell bodies and peripheral terminals of primary afferent nerves innervating the colon. Dorsal root ganglia neurons retrogradely labeled from the colon in short-term culture responded to addition of NMDA with increased intracellular [Ca2+]. Activation of peripheral NMDA receptors in colonic tissue sections caused Ca2+-dependent release of the proinflammatory neuropeptides, calcitonin gene-related peptide and substance P. Behavioral pain responses to noxious mechanical stimulation were inhibited in a reversible, dose-dependent manner by intravenous administration of memantine, a noncompetitive antagonist of the NMDA receptor. Single fiber recordings of decentralized pelvic nerves showed that colorectal distention responsive afferent nerve activity was inhibited by memantine. CONCLUSIONS: Peripheral NMDA receptors are important in normal visceral pain transmission, and may provide a novel mechanism for development of peripheral sensitization and visceral hyperalgesia.

NK1 receptor stimulation causes contraction and inositol phosphate increase in medium-size human isolated bronchi.

Although contraction of human isolated bronchi is mediated mainly by tachykinin NK2 receptors, NK1 receptors, via prostanoid release, contract small-size (approximately 1 mm in diameter) bronchi. Here, we have investigated the presence and biological responses of NK1 receptors in medium-size (2-5 mm in diameter) human isolated bronchi. Specific staining was seen in bronchial sections with an antibody directed against the human NK1 receptor. The selective NK1 receptor agonist, [Sar(9), Met(O2)(11)]SP, contracted about 60% of human isolated bronchial rings. This effect was reduced by two different NK1 receptor antagonists, CP-99,994 and SR 140333. Contraction induced by [Sar(9), Met(O2)(11)]SP was independent of acetylcholine and histamine release and epithelium removal, and was not affected by nitric oxide synthase and cyclooxygenase (COX) inhibition. [Sar(9), Met(O2)(11)]SP increased inositol phosphate (IP) levels, and SR 140333 blocked this increase, in segments of medium- and small-size (approximately 1 mm in diameter) human bronchi. COX inhibition blocked the IP increase induced by [Sar(9), Met(O2)(11)]SP in small-size, but not in medium-size, bronchi. NK1 receptors mediated bronchoconstriction in a large proportion of medium-size human bronchi. Unlike small-size bronchi this effect is independent of prostanoid release, and the results are suggestive of a direct activation of smooth muscle receptors and IP release.

Anandamide excites central terminals of dorsal root ganglion neurons via vanilloid receptor-1 activation.

Recently, the cannabinoid (CB) receptor agonist anandamide (AEA) has been shown to excite perivascular terminals of primary sensory neurons via activation of the vanilloid receptor-1 (VR-1). To determine whether AEA stimulates central terminals of these neurons, via VR-1 activation, we studied the release of calcitonin gene-related peptide (CGRP)- and substance P (SP)-like immunoreactivities (LI) from slices of rat dorsal spinal cord. Mobilization of Ca(2+) in rat dorsal root ganglion (DRG) neurons in culture was also studied. AEA (0.1-10 micrometer) increased the outflow of CGRP-LI and SP-LI from slices of the rat dorsal spinal cord in a Ca(2+)-dependent manner and increased [Ca(2+)](i) in capsaicin-sensitive cultured DRG neurons. Both effects of AEA were abolished by capsaicin pretreatment and by the VR-1 antagonist capsazepine but not affected by the CB receptor antagonists AM281 or AM630. Both neuropeptide release and Ca(2+) mobilization induced by electrical field stimulation (EFS) were inhibited by a low concentration of AEA (10 nm). Inhibition by AEA of EFS-induced responses was reversed by AM281 and AM630, but was not affected by capsazepine. Results indicate that stimulation of VR-1 with high concentrations of AEA excites central terminals of capsaicin-sensitive DRG neurons, thus causing neuropeptide release in the dorsal spinal cord. This novel activity opposes the CB receptor-mediated inhibitory action of low concentrations AEA. However, only if large amounts of endogenous AEA could be produced at the level of the dorsal spinal cord, they may not inhibit, but rather activate, nociceptive sensory neurons.

Evidence that PAR-1 and PAR-2 mediate prostanoid-dependent contraction in isolated guinea-pig gallbladder.

We have investigated the ability of protease-activated receptor-1 (PAR-1), PAR-2, PAR-3 and PAR-4 agonists to induce contractile responses in isolated guinea-pig gallbladder. Thrombin, trypsin, mouse PAR-1 activating (SFLLRN-NH(2)) peptide, and mouse PAR-2 activating (SLIGRL-NH(2)) and human PAR-2 activating (SLIGKV-NH(2)) peptides produced a concentration-dependent contractile response. Mouse PAR-4 activating (GYPGKF-NH(2)) peptide, the mouse PAR-1 reverse (NRLLFS-NH(2)) peptide, the mouse PAR-2 reverse (LRGILS-NH(2)) and human PAR-2 reverse (VKGILS-NH(2)) peptides caused negligible contractile responses at the highest concentrations tested. An additive effect was observed following the contractile response induced by either trypsin or thrombin, with the addition of a different PAR agonist (SFLLRN-NH(2) and SLIGRL-NH(2), respectively). Desensitization to PAR-2 activating peptide attenuated the response to trypsin but failed to attenuate the response to PAR-1 agonists, and conversely desensitization to PAR-1 attenuated the response to thrombin but failed to alter contractile responses to PAR-2 agonists. The contractile responses produced by thrombin, trypsin, SFLLRN-NH(2) and SLIGRL-NH(2) were markedly reduced in the presence of the cyclo-oxygenase inhibitor, indomethacin, whilst the small contractile response produced by NRLLFS-NH(2) and LRGILS-NH(2) were insensitive to indomethacin. The contractile responses to thrombin, trypsin, SFLLRN-NH(2) and SLIGRL-NH(2) were unaffected by the presence of: the non-selective muscarinic antagonist, atropine; the nitric oxide synthase inhibitor, L-NAME; the sodium channel blocker, tetrodotoxin; the combination of selective tachykinin NK(1) and NK(2) receptor antagonists, (S)-1-[2-[3-(3,4-dichlorphenyl)-1 (3-isopropoxyphenylacetyl) piperidin-3-yl] ethyl]-4-phenyl-1 azaniabicyclo [2.2.2] octane chloride (SR140333) and (S)-N-methyl-N-[4-acetylamino-4-phenylpiperidino-2-(3, 4-dichlorophenyl)-butyl] benzamide (SR48968), respectively. The results indicate that PAR-1 and PAR-2 activation causes contractile responses in the guinea-pig gallbladder, an effect that is mediated principally by prostanoid release, and is independent of neural mechanisms.

Presence and bronchomotor activity of protease-activated receptor-2 in guinea pig airways.

The protease activated receptor-2 (PAR-2) belongs to a family of G-protein-coupled receptors that are activated by proteolysis. Trypsin cleaves PAR-2, exposing an N-terminal tethered ligand (SLIGRL) that activates the receptor. Messenger RNA (mRNA) for PAR-2 was found in guinea pig airway tissue by reverse transcription-polymerase chain reaction, and PAR-2 was found by immunohistochemistry in airway epithelial and smooth-muscle cells. In anesthetized guinea pigs, trypsin and SLIGRL-NH(2) (given intratracheally or intravenously) caused a bronchoconstriction that was inhibited by the combination of tachykinin-NK(1) and -NK(2) receptor antagonists and was potentiated by inhibition of nitric oxide synthase (NOS). Trypsin and SLIGRL-NH(2) relaxed isolated trachea and main bronchi, and contracted intrapulmonary bronchi. Relaxation of main bronchi was abolished or reversed to contraction by removal of epithelium, administration of indomethacin, and NOS inhibition. PAR-1, PAR-3, and PAR-4 were not involved in the bronchomotor action of either trypsin or SLIGRL-NH(2), because ligands of these receptors were inactive either in vitro or in vivo, and because thrombin (a PAR-1 and PAR-3 agonist) did not show cross-desensitization with PAR-2 agonists in vivo. Thus, we have localized PAR-2 to the guinea-pig airways, and have shown that activation of PAR-2 causes multiple motor effects in these airways, including in vivo bronchoconstriction, which is in part mediated by a neural mechanism.

Agonists of proteinase-activated receptor 2 induce inflammation by a neurogenic mechanism.

Trypsin and mast cell tryptase cleave proteinase-activated receptor 2 and, by unknown mechanisms, induce widespread inflammation. We found that a large proportion of primary spinal afferent neurons, which express proteinase-activated receptor 2, also contain the proinflammatory neuropeptides calcitonin gene-related peptide and substance P. Trypsin and tryptase directly signal to neurons to stimulate release of these neuropeptides, which mediate inflammatory edema induced by agonists of proteinase-activated receptor 2. This new mechanism of protease-induced neurogenic inflammation may contribute to the proinflammatory effects of mast cells in human disease. Thus, tryptase inhibitors and antagonists of proteinase-activated receptor 2 may be useful anti-inflammatory agents.

Evidence for in vitro expression of B1 receptor in the mouse trachea and urinary bladder.

1. Motor responses to des-Arg9-bradykinin and bradykinin were studied in the isolated mouse trachea (precontracted with carbachol, 10 microM) and the urinary bladder of either Swiss, C57B1/6J or bradykinin B2 receptor knockout (Bk2r(-/-)) mice after 1-6 h in vitro. The expression of mRNA for the mouse B1 receptor in tracheal and urinary bladder tissues was also studied by using Northern blot analysis. 2. In isolated tracheae, des-Arg9-bradykinin produced a relaxant response that increased over time: no response was observed after 1 h of incubation, whereas after 6 h the maximum response (1 microM) was 68-84% of the relaxation produced by isoproterenol (1 microM) in the three mouse strains. The relaxant response to bradykinin (1 microM) observed at 1 h (38-51% of isoproterenol) was increased (62-65% of isoproterenol) after 6 h in Swiss and C57B1/6J mice, but was absent in Bk2r(-/-) mice. In the presence of cycloheximide, des-Arg9-bradykinin did not cause any response at 6 h. 3. Similar findings were obtained in the urinary bladder: at 1 h des-Arg9-bradykinin (1 microM) did not cause any motor effect, whereas at 6 h it caused a contraction that was 28-59% of that produced by carbachol (1 microM) in the three mouse strains. Cycloheximide blocked the response to des-Arg9-bradykinin. Bradykinin (1 microM) contracted urinary bladders at 1 h (34-35% of carbachol), as well as at 6 h (66-77% of carbachol) in Swiss and C57B1/6J strains, but was without effect in Bk2r(-/-) mice. 4. Northern blot hybridization with a specific cDNA probe against mouse B1 receptor mRNA using total RNA extracted from tracheae and urinary bladders freshly removed from Swiss and Bk2r(-/-) mice revealed minimal expression. However, marked hybridization was detected 150 min after in vitro exposure in both tissues. 5. Evidence is provided that in vitro exposure of mouse trachea and urinary bladder causes a time-dependent induction of B1 receptors that cause relaxation and contraction, respectively.

Nociceptin receptor activation inhibits tachykinergic non adrenergic non cholinergic contraction of guinea pig isolated bronchus.

We studied the action of nociceptin (NC) on the atropine-resistant contractions of the guinea pig isolated bronchus evoked by the electrical field stimulation (EFS), an effect that is mediated by the activation of excitatory non adrenergic-non cholinergic (eNANC) nerves and the subsequent release of tachykinins. The functional site by which NC acts in this preparation was investigated using few different NC receptor agonists and the newly discovered NC receptor antagonist, [Phe1psi(CH2-NH)Gly2]NC(1-13)NH2 ([F/G]NC(1-13)NH2). NC inhibited in a concentration dependent manner (pEC50 7.14; Em - 87 +/- 3% of control values) EFS induced contractions. NC effect was mimicked by the NC analogues, NCNH2 and NC(1-13)NH2, but not by NC(1-9)NH2. NC (1 microM) did not affect the contractile effects of exogenously applied neurokinin A (1 microM). [F/G]NC(1-13)NH2 (10 microM) completely prevented the inhibition induced by NC (1 microM), whereas naloxone (1 microM) was found inactive. Both naloxone and ([F/G]NC(1-13)NH2 were per se inactive on basal resting tone as well as on the electrically induced contractions. The present findings show that NC inhibits the atropine-resistant EFS-induced contraction in the guinea pig bronchus by inhibiting eNANC nerves, and suggest the presence of NC receptors, distinct from opioid receptors, on the nerves of the guinea pig bronchus.

Tachykinins and kinins in airway allergy.

Using models of airway diseases, our understanding of the role of tachykinins and kinins in airway pathophysiology has been greatly enhanced by the recent development of a large series of peptide, peptoid and non-peptide antagonists for tachykinin and kinin receptors. This article reviews the experimental findings of the contribution of kinins and tachykinins and their respective receptors, in models of airway inflammation in response to agents known to trigger or worsen asthma attacks, such as antigen and cold air. Some new antagonists, mostly of a non-peptide nature, exhibit excellent pharmacodynamic and pharmacokinetic profiles; a brief account of early clinical studies in which they have been used is also given.