<i>Saccharomyces cerevisiae</i>as a Model to Confirm the Ability of FTIR to Evaluate the Presence of Protein Aggregates

It is known that the presence of protein aggregates in biological samples is associated with natural aging processes and age-related diseases. The objective of this technical study was to evaluate the potential of Fourier Transform Infrared Spectroscopy to identify the presence of protein aggregates in Saccharomyces cerevisiae containing high levels of protein aggregates. We acquired ATR-FTIR spectra at mid-infrared range (between 4000 and 600 cm-1) and used multivariate analysis to analyze the data. Significant differences between spectra of wild type and mutant strains in the spectral range assigned to proteins were observed. In particular, an increase in β-sheet structures in mutant strains (spectral signals at 1683 and 1628 cm-1) was observed, indicating the putative presence of protein aggregates. These results prove the capacity of FTIR to evaluate changes in protein conformation, mainly protein aggregation, in a fast, simple and non-expensive way, producing insights on the possible application of this technique to the detection of protein aggregates in human biological samples.

The role of surface functionalization of silica nanoparticles for bioimaging

Among the several types of inorganic nanoparticles available,silica nanoparticles(SNP)have earned their relevance in biological applications namely,as bioimaging agents.In fact,uorescent SNP(FSNP)have been explored in this-eld as protective nanocarriers,overcoming some limitations presented by conventional organic dyes such as high photobleaching rates.A crucial aspect on the use of uorescent SNP relates to their surface properties,since it determines the extent of interaction between nanoparticles and biological systems,namely in terms of colloidal stability in water,cellular recognition and internalization,tracking,biodistribution and speci-city,among others.Therefore,it is imperative to understand the mechanisms underlying the interaction between biosystems and the SNP surfaces,making surface functionalization a relevant step in order to take full advantage of particle properties.The versatility of the surface chemistry on silica platforms,together with the intrinsic hydrophilicity and biocompatibility,make these systems suitable for bioimaging applications,such as those mentioned in this review.

What we have learned from urinary bladder cancer models

Urinary bladder cancer(UBC)is a heterogeneous disease with highly variable clinical outcomes and responses to chemotherapy.Despite some advances in the molecular understanding of UBC,this knowledge still has not been translated to the clinic in terms of improvements in the prognosis and treatment of patients.Suitable urinary bladder tumor models representative of the human disease in terms of histology and behavior are needed to study factors involved in tumor initiation,progression and metastasis.Further,accurate model systems would facilitate identification of new therapeutic targets and predictive markers that could lead to optimization of existing therapies and development of new ones.Many established cancer cell lines derived from human urinary bladder tumors representing different grades and stages have been used as experimental models for UBC study.These cell lines reflect some of the genetic and morphologic alterations observed in human urothelial carcinoma and serve as simplified models to study the behavior of cancer cells in vitro.However,their translational potential is limited due to the artificial conditions,in which the cells are maintained,grown and tested.Animal models offer a more complex and realistic model for the establishment,development,and progression of tumors as well as to evaluate new therapeutic approaches.Over the years,the authors'group has worked with several UBC cell lines,established and characterized chemically induced UBC models,and patient-derived xenografts models.In this study,the authors will provide a summary of the UBC models developed by their group,analyze their translational potential and weaknesses,and define areas that remain to be explored.