MicroRNAs are small, noncoding RNAs that regulate gene expression by posttranscriptional regulation of target genes. miR-200 family and miR-205 have been shown experimentally to regulate epithelial-mesenchymal transition. As epithelial-mesenchymal transition is the postulated pathogenetic mechanism in spindle cell carcinoma, we analyzed the expression of these microRNAs in spindle cell carcinoma of the head and neck in comparison to conventional squamous cell carcinoma of similar location and stage. We also analyzed the expression of classic and desmosomal cadherins, which are believed to be important targets during epithelial-mesenchymal transition. Forty-five cases of spindle cell carcinoma and 45 cases of squamous cell carcinoma of the head and neck were analyzed using real-time polymerase chain reaction for microRNAs, and immunohistochemistry for classic cadherins (E- and N-cadherins)and desmosomal cadherins. We found a significant down-regulation of the miR-200 family and miR-205, loss of desmosomal cadherins, and an altered expression of classic cadherins in spindle cell carcinoma in comparison to squamous cell carcinoma. Down-regulation of the miR-200 family and miR-205 strongly supports the postulated role of epithelial-mesenchymal transition in spindle cell carcinoma. These microRNAs act on transcription repressors that were also up-regulated in our cases of spindle cell carcinoma,both on mRNA and on protein levels. The result is not only an altered expression of classic cadherins in adherens junctions but also a complete loss of desmosomal cadherins.
COBISS.SI-ID: 28112089
Inverted papillomas (IPs) are the most frequent type of sinonasal papillomas. These benign but destructive lesions are known for their high recurrence rate, probably due to incomplete excision. Our aim was to investigate the frequency of human papillomavirus (HPV) infection inpatients with IPs and in IPs associated with squamous cell carcinoma (IPsSCC) and to compare it with the frequency of HPV infections in the control group. The influence of HPV infection on the malignant alteration and recurrence rate of IPs was also evaluated. Paraffin-embedded tissue samples from 68 patients with sinonasal IPs and 5 patients with IPsSCC were analyzed in this retrospective study. The control group consisted of 47 patients who had undergone septoplasty or mucotomy of the inferior turbinate. PCR amplification with consensus primer sets was performed to detect alpha-HPVs, and direct sequencing of the PCR products with the same primers was used to determine the HPV genotypes in the samples. We detected HPV DNA in 20 (30.3%) patients with IPs, in 3 (60%) patients with IPsSCC, and in 6 (13%) patients from the control group. The frequency of HPV infection in the study group was statistically significantly higher (p = 0.032) than in the control group. The presence of HPV DNA was not a statistically significant predictor of the recurrence of IPs (p = 0.745) nor was it a statistically significant risk factor for associated SCC (p = 0.32). Since HPV type 11 was the predominant genotype in the IPs, IPsSCC, and in the control cases, we presume that HPV infection may represent incidental colonization rather than being an important etiological factor of IPs.
COBISS.SI-ID: 1155963
Sustained increase in intraocular pressure represents a major risk factor for eye disease, yet the cellular mechanisms of pressure transduction in the posterior eye are essentially unknown. Here we show that the mouse retina expresses mRNA and protein for the polymodal transient receptor potential vanilloid 4 (TRPV4) cation channel known to mediate osmotransduction and mechanotransduction. TRPV4 antibodies labeled perikarya, axons, and dendrites of retinal ganglion cells (RGCs) and intensely immunostained the optic nerve head. Muller glial cells, but not retinal astrocytes or microglia, also expressed TRPV4 immunoreactivity. The selective TRPV4 agonists 4alpha-PDD and GSK1016790A elevated Ca2+ in dissociated RGCs in a dose-dependent manner, whereas the TRPV1 agonist capsaicin had no effect on Ca2+(RGC). Exposure tohypotonic stimulation evoked robust increases in Ca2+(RGC). RGC responses to TRPV4-selective agonists and hypotonic stimulation were absent in Ca2+ -free saline and were antagonized by the nonselective TRP channel antagonists Ruthenium Red and gadolinium, but were unaffected by the TRPV1 antagonist capsazepine. TRPV4-selective agonists increased the spiking frequency recordedfrom intact retinas recorded with multielectrode arrays. Sustained exposure to TRPV4 agonists evoked dose-dependent apoptosis of RGCs. Our results demonstrate functional TRPV4 expression in RGCs and suggest that its activation mediates response to membrane stretch leading to elevated Ca2+ and augmented excitability. Excessive Ca2+ influx through TRPV4 predisposes RGCs to activation of Ca2+ -dependent proapoptotic signaling pathways, indicating that TRPV4 is a component of the response mechanism to pathological elevations of intraocular pressure.
COBISS.SI-ID: 29590233