Transient Receptor Potential Ankyrin 1 Ion Channel Is Expressed in Osteosarcoma and Its Activation Reduces Viability

Osteosarcoma is a highly malignant, painful cancer with poor treatment opportunities and a bad prognosis. Transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) receptors are non-selective cation channels that have been of great interest in cancer, as their expression is increased in some malignancies. In our study we aim to characterize the expression and functionality of the TRPA1 and TRPV1 channels in human and mouse osteosarcoma tissues and in a mouse cell line. TRPA1/Trpa1 and TRPV1/Trpv1 mRNA expressions were demonstrated by PCR gel electrophoresis and RNAscope in situ hybridization. The function of these channels was confirmed by their radioactive 45Ca2+ uptake in response to the TRPA1 agonist, Allyl-isothiocyanate (AITC), and TRPV1 agonist, capsaicin, in K7M2 cells. An ATP-based K2M7 cell viability luminescence assay was used to determine cell viability after AITC or capsaicin treatments. Both TRPA1/Trpa1 and TRPV1/Trpv1 were expressed similarly in human and mouse osteosarcoma tissues, while Trpa1 transcripts were more abundantly present in K7M2 cells. TRPA1 activation with 200 µM AITC induced a significant 45Ca2+ influx into K7M2 cells, and the antagonist attenuated this effect. In accordance with the lower Trpv1 expression, capsaicin induced a moderate 45Ca2+ uptake, which did not reach the level of statistical significance. Both AITC and capsaicin significantly reduced K7M2 cell viability, demonstrating EC50 values of 22 µM and 74 µM. The viability-decreasing effect of AITC was significantly but only partially antagonized by HC-030031, but the action of capsaicin was not affected by the TRPV1 antagonist capsazepine. We provide here the first data on the functional expression of the TRPA1 and TRPV1 ion channels in osteosarcoma, suggesting novel diagnostic and/or therapeutic perspectives.

Impact of cytomegalovirus infection on biliary disease after liver transplantation - maybe an essential factor

BACKGROUND

Cytomegalovirus (CMV) infection is common in liver transplant (LT)_ recipients, and biliary complications occur in a large number of patients. It has been reported that CMV-DNA is more detectable in bile than in blood.

AIM

To investigate the effects of CMV infection on biliary complications by comparing the levels of CMV-DNA in the bile and blood of patients after LT.

METHODS

We conducted a retrospective analysis of 57 patients who underwent LT, 10 of these patients had no biliary complications and 47 patients had biliary complications. We also compared the levels of CMV-DNA in patients’ bile and blood, which were sampled concurrently. We used RNAscope technology to identify CMV in paraffin-embedded liver sections.

RESULTS

CMV-DNA was not detected in bile samples and was detected in 2 blood samples from patients without biliary complications. In the 47 patients with biliary complications, CMV-DNA was detected in 22 bile samples and 8 blood samples, both bile and blood samples were positive for CMV-DNA in 6 patients. The identification rate of CMV-DNA in blood was 17.0%, and was 46.8% in bile. Moreover, tissue samples from 4 patients with biliary complications tested positive using RNAscope technology but were negative with hematoxylin and eosin staining. During the follow-up period, graft failure occurred in 13 patients with biliary complications, 8 of whom underwent retransplantation, and 3 died. CMV-DNA in bile was detected in 9 of 13 patients with graft failure.

CONCLUSION

In patients with biliary complications, the identification rate of CMV-DNA in bile was higher than that in blood. Blood CMV-DNA negative patients with biliary complications should still be monitored for CMV-related biliary tract diseases. Potential occult CMV infection may also be a contributing etiological factor in the development of graft failure.

Human Somatostatin SST4 Receptor Transgenic Mice: Construction and Brain Expression Pattern Characterization

Somatostatin receptor subtype 4 (SST₄) has been shown to mediate analgesic, antidepressant and anti-inflammatory functions without endocrine actions; therefore, it is proposed to be a novel target for drug development. To overcome the species differences of SST₄ receptor expression and function between humans and mice, we generated an SST₄ humanized mouse line to serve as a translational animal model for preclinical research. A transposon vector containing the hSSTR4 and reporter gene construct driven by the hSSTR4 regulatory elements were created. The vector was randomly inserted in Sstr4-deficient mice. hSSTR4 expression was detected by bioluminescent in vivo imaging of the luciferase reporter predominantly in the brain. RT-qPCR confirmed the expression of the human gene in the brain and various peripheral tissues consistent with the in vivo imaging. RNAscope in situ hybridization revealed the presence of hSSTR4 transcripts in glutamatergic excitatory neurons in the CA1 and CA2 regions of the hippocampus; in the GABAergic interneurons in the granular layer of the olfactory bulb and in both types of neurons in the primary somatosensory cortex, piriform cortex, prelimbic cortex and amygdala. This novel SST₄ humanized mouse line might enable us to investigate the differences of human and mouse SST₄ receptor expression and function and assess the effects of SST₄ receptor agonist drug candidates.

Presence of lytic Epstein-Barr virus infection in nasopharyngeal carcinoma

BACKGROUND

Chromogenic Epstein-Barr virus-encoded RNA (EBER) in situ hybridization (EBER-ISH) is the gold standard to detect Epstein-Barr virus (EBV) but it is difficult to use in conjunction with immunohistochemistry (IHC). In this study, our purpose was to validate the sensitivity and specificity of RNAscope in detection of EBV infection in nasal epithelium and its stroma.

METHODS

Fluorescence-based RNAscope EBER-ISH, BRLF1-ISH, and lineage marker-IHC were performed on archived formalin-fixed paraffin-embedded tissues from normal nasal cavity (n = 5), nasopharynx (n = 8), and nasopharyngeal carcinoma (NPC) specimens (n = 10).

RESULTS

The EBERs were detected in 10 of 10 NPC samples but was absent in all normal tissues from the nasal cavity and nasopharynx. The EBERs were exclusively located in pan-cytokeratin (pan-CK)-positive tumor epithelial cells but not in CD45-positive leukocytes and vimentin-positive stromal fibroblasts. The level of EBER expression varied in tumor cells within patient and between patients as well. Additionally, 5 of 10 patients had positive BRLF-ISH.

CONCLUSION

We developed a simple and reproducible method to simultaneously detect mRNA and protein in formalin-fixed paraffin-embedded tissues of NPC. As a single staining, traditional EBER continues to be useful; however, for interpretation of the phenotype of EBV-infected cells, RNAscope is superior. Significantly, we showed that lytic EBV infection took place in NPC tumors.