Inhibitor of Wnt receptor 1 suppresses the effects of Wnt1, Wnt3a and ß­catenin on the proliferation and migration of C6 GSCs induced by low­dose radiation.

The radioresistance of glioma is an important cause of treatment failure and tumor aggressiveness. In the present study, under performed with linear accelerator, the effects of 0.3 and 3.0 Gy low­dose radiation (LDR) on the proliferation and migration of C6 glioma stem cells in vitro were examined by flow cytometric analysis, immunocytochemistry and western blot analysis. It was found that low­dose ionizing radiation (0.3 Gy) stimulated the proliferation and migration of these cells, while 3.0 Gy ionizing radiation inhibited the proliferation of C6 glioma stem cells, which was mediated through enhanced Wnt/ß­catenin signaling, which is associated with glioma tumor aggressiveness. LDR treatment increased the expression of the DNA damage marker γ­H2AX but promoted cell survival with a significant reduction in apoptotic and necrotic cells. When LDR cells were also treated with an inhibitor of Wnt receptor 1 (IWR1), cell proliferation and migration were significantly reduced. IWR1 treatment significantly inhibited Wnt1, Wnt3a and ß­catenin protein expression. Collectively, the current results demonstrated that IWR1 treatment effectively radio­sensitizes glioma stem cells and helps to overcome the survival advantages promoted by LDR, which has significant implications for targeted treatment in radioresistant gliomas.

Neurochemical features of endomorphin-2-containing neurons in the submucosal plexus of the rat colon.

AIM: To investigate the distribution and neurochemical phenotype of endomorphin-2 (EM-2)-containing neurons in the submucosal plexus of the rat colon. METHODS: The mid-colons between the right and left flexures were removed from rats, and transferred into Kreb's solution. For whole-mount preparations, the mucosal, outer longitudinal muscle and inner circular muscle layers of the tissues were separated from the submucosal layer attached to the submucosal plexus. The whole-mount preparations from each rat mid-colon were mounted onto seven gelatin-coated glass slides, and processed for immunofluorescence histochemical double-staining of EM-2 with calcitonin gene-related peptide (CGRP), choline acetyltransferase (ChAT), nitric oxide synthetase (NOS), neuron-specific enolase (NSE), substance P (SP) and vasoactive intestinal peptide (VIP). After staining, all the fluorescence-labeled sections were observed with a confocal laser scanning microscope. To estimate the extent of the co-localization of EM-2 with CGRP, ChAT, NOS, NSE, SP and VIP, ganglia, which have a clear boundary and neuronal cell outline, were randomly selected from each specimen for this analysis. RESULTS: In the submucosal plexus of the mid-colon, many EM-2-immunoreactive (IR) and NSE-IR neuronal cell bodies were found in the submucosal plexus of the rat mid-colon. Approximately 6 ± 4.2 EM-2-IR neurons aggregated within each ganglion and a few EM-2-IR neurons were also found outside the ganglia. The EM-2-IR neurons were also immunopositive for ChAT, SP, VIP or NOS. EM-2-IR nerve fibers coursed near ChAT-IR neurons, and some of these fibers were even distributed around ChAT-IR neuronal cell bodies. Some EM-2-IR neuronal cell bodies were surrounded by SP-IR nerve fibers, but many long processes connecting adjacent ganglia were negative for EM-2 immunostaining. Long VIP-IR processes with many branches coursed through the ganglia and surrounded the EM-2-IR neurons. The percentages of the EM-2-IR neurons that were also positive for ChAT, SP, VIP or NOS were approximately 91% ± 2.6%, 36% ± 2.4%, 44% ± 2.5% and 44% ± 4.7%, respectively, but EM-2 did not co-localize with CGRP. CONCLUSION: EM-2-IR neurons are present in the submucosal plexus of the rat colon and express distinct neurochemical markers.