Clostridium difficile is an opportunistic pathogen inhabiting the human gut, often being the aetiological agent of infections after a microbiota dysbiosis following, for example, an antibiotic treatment. C. difficile infections (CDI) constitute a growing health problem with increasing rates of morbidity and mortality at groups of risk, such as elderly and hospitalized patients, but also in populations traditionally considered low-risk. This could be related to the occurrence of virulent strains which, among other factors, have high-level of resistance to fluoroquinolones, more efficient sporulation and markedly high toxin production. Several novel intervention strategies against CDI are currently under study, such as the use of probiotics to counteract the growth and/or toxigenic activity of C. difficile. In this work, we have analyzed the capability of twenty Bifidobacterium and Lactobacillus strains, from human intestinal origin, to counteract the toxic effect of C. difficile LMG21717 upon the human intestinal epithelial cell line HT29. For this purpose, we incubated the bacteria together with toxigenic supernatants obtained from C. difficile. After this co-incubation new supernatants were collected in order to quantify the remnant A and B toxins, as well as to determine their residual toxic effect upon HT29 monolayers. To this end, the real time cell analyser (RTCA) model, recently developed in our group to monitor C. difficile toxic effect, was used. Results obtained showed that strains of Bifidobacterium longum and B. breve were able to reduce the toxic effect of the pathogen upon HT29, the RTCA normalized cell-index values being inversely correlated with the amount of remnant toxin in the supernatant. The strain B. longum IPLA20022 showed the highest ability to counteract the cytotoxic effect of C. difficile acting directly against the toxin, also having the highest capability for removing the toxins from the clostridial toxigenic supernatant. Image analysis showed that this strain prevents HT29 cell rounding; this was achieved by preserving the F-actin microstructure and tight-junctions between adjacent cells, thus keeping the typical epithelium-like morphology. Besides, preliminary evidence showed that the viability of B. longum IPLA20022 is needed to exert the protective effect and that secreted factors seems to have anti-toxin activity.

Sinonasal squamous cell carcinomas (SCC) are rare tumors, etiologically related to occupational exposure to wood and leather dust. In spite of surgical and radiotherapeutic advances, the 5 year survival is still 30–50%. Therefore, alternative treatment options are needed. We report the establishment and characterization of six unique human sinonasal SCC cell lines, named SCCNC1, 2, 4, 5, 6 and 7. In vitro growth and invasion characteristics were evaluated and genetic profiles were compared to those of the original primary tumors. The population doubling times ranged from 21 to 34 hours. Cell lines SCCNC2 and 7 were highly invasive in matrigel. Five cell lines carried a high number of copy number alterations, including amplifications and homozygous deletions, while one showed only three abnormalities. Sequence analysis revealed three cell lines with TP53 mutation and none with KRAS or BRAF. Overexpression of p53 was observed in five, and of EGFR in four cell lines. None of the cell lines showed strong immunopositivity of p16 or presence of human papilloma virus. In conclusion, we have created six new cell lines that are clinically and genetically representative of sinonasal SCC and that will be a useful tool for the preclinical testing of new therapeutic agents.

Novel markers to accurately predict the risk of malignant transformation in laryngeal epithelial precursor lesions (EPL) are needed. We tried to identify some molecular alterations occurring in laryngeal tumorigenesis. In this study, 60 paraffin-embedded EPL and 17 metachronous invasive carcinomas were immunostained for markers associated with proliferation (Ki67), cell cycle control (p53, p21, p16, p27, cyclin D1), and cell adhesion and invasion (laminin and β-catenin). Aberrant expression of p16 and p53 and positivity at cytoplasm for β-catenin and cyclin D1 were detected significantly in EPL with progression to invasive laryngeal carcinoma. All cases with basal and suprabasal reactivity of p53 showed β-catenin overexpression. We found that β-catenin protein expression increased significantly with the grade of dysplasia. This is one of the studies with the largest number of laryngeal EPL and invasive carcinoma studied sequentially. Our data confirm the role of some cell cycle regulatory proteins in the development of laryngeal carcinoma. Cytoplasmic retention of β-catenin in EPL seems to be related with more aggressive biological behavior. Combined increased p53 and cytoplasmic β-catenin protein expression could be biologically important in laryngeal tumorigenesis. Further research is required to clarify the involvement of β-catenin in the mechanism associated with malignant transformation in laryngeal tissues.

The genomic profile of sinonasal SCC showed a number of chromosomal regions with copy number changes similar to those known in HNSCC, in spite of the differences in etiology.

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