Collagen triple helix repeat containing-1 (CTHRC1) is a secreted protein involved in vascular remodeling, bone formation and developmental morphogenesis. CTHRC1 has recently been shown to be expressed in human cancers such as breast cancer and melanoma. In this study, we show that CTHRC1 is highly expressed in human pancreatic cancer tissues and plays a role in the progression and metastasis of the disease. CTHRC1 promoted primary tumor growth and metastatic spread of cancer cells to distant organs in orthotopic xenograft tumor mouse models. Overexpression of CTHRC1 in cancer cells resulted in increased motility and adhesiveness, whereas these cellular activities were diminished by down-regulation of the protein. CTHRC1 activated several key signaling molecules, including Src, focal adhesion kinase, paxillin, mitogen-activated protein kinase kinase (MEK), extracellular signal-regulated kinase and Rac1. Treatment with chemical inhibitors of Src, MEK or Rac1 and expression of dominant-negative Rac1 attenuated CTHRC1-induced cell migration and adhesion. Collectively, our results suggest that CTHRC1 has a role in pancreatic cancer progression and metastasis by regulating migration and adhesion activities of cancer cells.

Neuronal activity in the hypothalamic paraventricular nucleus (PVN), as well as sympathetic outflow from the PVN, is basally restrained by a GABAergic inhibitory tone. We recently showed that two complementary GABA A receptor-mediated modalities underlie inhibition of PVN neuronal activity: a synaptic, quantal inhibitory modality (IPSCs, I phasic ) and a sustained, non-inactivating modality (I tonic ). Here, we investigated the role of neuronal and/or glial GABA transporters (GATs) in modulating these inhibitory modalities, and assessed their impact on the activity of RVLM-projecting PVN neurons (PVN-RVLM neurons), and on PVN influence of renal sympathetic nerve activity (RSNA). Patch-clamp recordings were obtained from retrogradely labelled PVN-RVLM neurons in a slice preparation. The non-selective GAT blocker nipecotic acid (100-300 μm) caused a large increase in GABA A I tonic , and reduced IPSC frequency. These effects were replicated by β-alanine (100 μm), but not by SKF 89976A (30 μm), relatively selective blockers of GAT3 and GAT1 isoforms, respectively. Similar effects were evoked by the gliotoxin l-α-aminodipic acid (2 mm). GAT blockade attenuated the firing activity of PVN-RVLM neurons. Moreover, PVN microinjections of nipecotic acid in the whole animal diminished ongoing RSNA. A robust GAT3 immunoreactivity was observed in the PVN, which partially colocalized with the glial marker GFAP. Altogether, our results indicate that by modulating ambient GABA levels and the efficacy of GABA A I tonic , PVN GATs, of a likely glial location, contribute to setting a basal tone of PVN-RVLM firing activity, and PVN-driven RSNA.

Interactions between neurosteroids and GABA receptors have attracted particular attention in the supraoptic nucleus (SON). Although GABA(A) receptors (GABA(A)R) mediate a sustained tonic inhibitory current (I(tonic)), as well as conventional phasic inhibitory postsynaptic currents (IPSCs, I(phasic)) in the SON, whether the steroid modulation on I(tonic) is present in SON magnocelluar neurosecretory cells (MNCs) is unknown. Here, we addressed this question and gained insights into the potential molecular configuration of GABA(A) receptors mediating I(tonic) and conferring its neurosteroids sensitivity in SON MNCs. 4,5,6,7-tetrahydroisoxazolo[5,4-c]-pyridin-3-ol (THIP) (1 μM), a relatively selective extrasynaptic GABA(A)R agonist, facilitated I(tonic) without affecting the main characteristics of IPSCs, while DS-2, a relatively selective modulator of GABA(A)R δ-subunits, caused minimal changes in I(tonic) of SON MNCs. l-655,708, a relatively selective GABA(A)R α(5)-subunit inverse agonist, blocked ∼35% of the total I(tonic) both under basal and elevated ambient GABA concentration (3 μM). Facilitation of I(tonic) by benzodiazepines further supported the role of GABA(A)R γ(2)-subunit in I(tonic) of SON MNCs. Quantitative RT-PCR analysis showed much lesser expression of GABA(A)R δ-subunit than the α(5) or γ(2)-subunit in the SON. Allopregnanolone and 3α,5α-tetrahydrodeoxycorticosterone increased both I(tonic) and I(phasic) in SON MNCs, respectively, although more than 90% of the current increase was mediated by I(tonic) during the neurosteroid facilitation. Finally, l-655,708 attenuated the neurosteroid facilitation of I(tonic) but not of I(phasic). Altogether, our results suggest that I(tonic), mediated mainly by benzodiazepine-sensitive GABA(A)Rs containing α(5)-, β-, and γ(2)-, and to a lesser extent, δ-subunits, is a potential target of neurosteroid modulation in SON neurons.