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Colorectal cancer (CRC) is the fourth cause of death from cancer worldwide mainly due to the high incidence of drug‐resistance. During a screen for new actionable targets in drug‐resistant tumours we recently identified p65BTK – a novel oncogenic isoform of Bruton's tyrosine kinase. Studying three different cohorts of patients here we show that p65BTK expression correlates with histotype and cancer progression. Using drug‐resistant TP53‐null colon cancer cells as a model we demonstrated that p65BTK silencing or chemical inhibition overcame the 5‐fluorouracil resistance of CRC cell lines and patient‐derived organoids and significantly reduced the growth of xenografted tumours. Mechanistically, we show that blocking p65BTK in drug‐resistant cells abolished a 5‐FU‐elicited TGFB1 protective response and triggered E2F‐dependent apoptosis. Taken together, our data demonstrated that targeting p65BTK restores the apoptotic response to chemotherapy of drug‐resistant CRCs and gives a proof‐of‐concept for suggesting the use of BTK inhibitors in combination with 5‐FU as a novel therapeutic approach in CRC patients. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

VGF mRNA and its precursor-derived products are selectively expressed in certain neurons and promptly respond to neurotrophins and to neural/electrical activity. Proteomic studies have previously revealed a reduction in some VGF peptides in the cerebrospinal fluid of patients affected by Alzheimer's disease and other conditions, suggesting their potential diagnostic and clinical significance. As the presence of VGF peptides within the human cortex has been somewhat elucidated, they were studied postmortem in the frontal, parietal, and temporal cortex areas of control subjects and patients affected by Parkinson's disease, and in parietal cortex samples from patients with Alzheimer's disease. We raised antibodies to the C-/N-terminal portions of the proVGF precursor protein, to the TPGH and TLQP sequences and to the neuroendocrine regulatory peptide (NERP)-1, all used for enzyme-linked immunosorbent assay coupled with gel chromatography and for immunohistochemistry. In the control brain samples, the levels of TPGH and C-terminus peptides were about 130-200 and 700-2000 pmol g, respectively, the N-terminus and NERP-1 peptides were less represented (about 10-30 and 4-20 pmol g, respectively), and the TLQP peptides were below detection limits. Upon gel chromatography, the VGF antisera mainly revealed small molecular weight forms (i.e. about 0.8-1.3 kDa), whereas VGF immunolocalisation was found within different types of neuron in rat and bovine brain cortices. In the Parkinson's disease samples, a clear-cut decrease was revealed in the parietal cortex only, exclusively for TPGH and NERP-1 peptides, whereas in the Alzheimer's disease samples, a reduction in all of the VGF peptides was shown. The results suggest the involvement of VGF in the physiological or pathophysiological mechanisms occurring in the parietal cortex of patients with Parkinson's and Alzheimer's diseases. [ABSTRACT FROM AUTHOR]

Oxytocin (80 ng) injected into the caudal mesencephalic ventral tegmental area (VTA) of male rats induces penile erection. Such an effect occurs together with an increase in nitric oxide (NO) production, as measured by the augmented concentration of NO2− and NO3− found in the dialysate obtained from this brain area by means of intracerebral microdialysis. Both effects are abolished by d(CH2)5Tyr(Me)2-Orn8-vasotocin (1 μg), an oxytocin receptor antagonist, by S-methyl-l-thiocitrulline acetate (20 μg), a neuronal NO synthase inhibitor, or by ω-conotoxin GVIA (50 ng), a N-type Ca2+ channel blocker, all injected into the VTA 15 min before oxytocin. In contrast, 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (40 μg), a guanylate cyclase inhibitor, given into the VTA 15 min before oxytocin, abolishes penile erection, but not the increase in NO production, while haemoglobin (40 μg), a NO scavenger, injected immediately before oxytocin reduces the increase in NO production, but not penile erection. 8-Bromo-cyclic guanosine monophosphate (0.5–10 μg) microinjected into the VTA induces penile erection with an inverted U-shaped dose–response curve; the maximal effective dose being 3 μg. Immunohistochemistry reveals that in the caudal VTA oxytocin-containing axons/fibres (originating from the paraventricular nucleus of the hypothalamus) contact cell bodies of mesolimbic dopaminergic (tyrosine hydroxylase-positive) neurons containing both NO synthase and guanylate cyclase. These results suggest that oxytocin injected into the VTA induces penile erection by activating NO synthase in the cell bodies of mesolimbic dopaminergic neurons. NO in turn activates guanylate cyclase present in these neurons, thereby increasing cyclic GMP concentration. [ABSTRACT FROM AUTHOR]

The neuropeptide oxytocin (20–100 ng), induces penile erection when injected unilaterally into the caudal but not rostral mesencephalic ventral tegmental area (VTA) of male Sprague–Dawley rats. Such pro-erectile effect started 30 min after treatment and was abolished by the prior injection of d(CH2)5Tyr(Me)2-Orn8-vasotocin (1 µg), an oxytocin receptor antagonist injected into the same caudal ventral tegmental area or of haloperidol (1 µg), a dopamine receptor antagonist, injected either into the nucleus accumbens shell (NAs) or into the paraventricular nucleus of the hypothalamus (PVN) ipsilateral to the injected ventral tegmental area. Penile erection was seen 15 min after the occurrence of, or concomitantly to, an increase in extracellular dopamine and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the dialysate obtained from the nucleus accumbens or the paraventricular nucleus, which was also abolished by d(CH2)5Tyr(Me)2-Orn8-vasotocin (1 µg), injected into the ventral tegmental area before oxytocin. In the caudal ventral tegmental area oxytocin-containing axons/fibres (originating from the paraventricular nucleus) appeared to closely contact cell bodies of mesolimbic dopaminergic neurons retrogradely labelled with Fluorogold injected into the nucleus accumbens shell, suggesting that oxytocin effects are mediated by the activation of mesolimbic dopaminergic neurons, followed in turn by that of incerto-hypothalamic dopaminergic neurons impinging on oxytocinergic neurons mediating penile erection. As the stimulation of paraventricular dopamine receptors not only induces penile erection, but also increases mesolimbic dopamine neurotransmission by activating oxytocinergic neurons, these results provide further support for the existence of a neural circuit in which dopamine and oxytocin influence both the consummatory and motivational/rewarding aspects of sexual behaviour. [ABSTRACT FROM AUTHOR]

The effect of five peptides derived from the C-terminal portion of rat pro-VGF (VGF577-617, VGF588-617, VGF599-617, VGF556-576 and VGF588-597) on penile erection was studied after injection into the hypothalamic paraventricular nucleus of male rats. VGF577-617, VGF588-617, VGF599-617 and, to a lower extent, VGF588-597 (0.1–2 µg) induced penile erection episodes in a dose-dependent manner when injected into the paraventricular nucleus, while VGF556-576 was ineffective. VGF588-617-induced penile erection was reduced by nitroω-l-arginine methylester (L-NAME; 20 µg), by morphine (5 µg) and by muscimol (1 µg), but not by dizocilpine[(+)MK-801; 1 µg], nor bycis-flupenthixol (10 µg) given into the paraventricular nucleus 10 min before the VGF peptide. d(CH2)5Tyr(Me)-Orn8-vasotocin (1 µg) effectively reduced VGF588-617-induced penile erection when given into the lateral ventricles but not when injected into the paraventricular nucleus. Immunocytochemistry with antibodies specific for the C-terminal nonapeptide sequence of pro-VGF (VGF609-617) revealed numerous neuronal fibres and terminals within the paraventricular nucleus, including its parvocellular components. Here, many immunostained neuronal terminals impinged on parvocellular oxytocinergic neurons. The present results show for the first time that certain pro-VGF C-terminus-derived peptides promote penile erection when injected into the paraventricular nucleus and suggest that, within this nucleus, these or closely related pro-VGF-derived peptides may be released to influence sexual function by activating paraventricular oxytocinergic neurons mediating penile erection. [ABSTRACT FROM AUTHOR]