The 14-3-3 protein family of eukaryotic regulators was studied in Echinococcus granulosus, the causative agent of cystic hydatid disease. These proteins mediate important cellular processes in eukaryotes and are expected to play important roles in parasite biology. Six isoforms of E. granulosus 14-3-3 genes and proteins (Eg14-3-3.1-6) were analyzed, and their phylogenetic relationships were established with bona fide 14-3-3 orthologous proteins from eukaryotic species. Eg14-3-3 isoforms with previous evidence of expression (Eg14-3-3.1-4) in E. granulosus pathogenic larval stage (metacestode) were cloned, and recombinant proteins were used for functional studies. These protein isoforms were detected in different components of E. granulosus metacestode, including interface components with the host. The roles that are played by Eg14-3-3 proteins in parasite biology were inferred from the repertoires of interacting proteins with each isoform, as assessed by gel overlay, cross-linking, and affinity chromatography assays. A total of 95 Eg14-3-3 protein ligands were identified by mass spectrometry. Eg14-3-3 isoforms have shared partners (44 proteins), indicating some overlapping functions; however, they also bind exclusive partners (51 proteins), suggesting Eg14-3-3 functional specialization. These ligand repertoires indicate the involvement of Eg14-3-3 proteins in multiple biochemical pathways in the E. granulosus metacestode and note some degree of isoform specialization.

Background/Aim: Extracellular vesicles (EVs) can mediate drug resistance within the tumor microenvironment by delivering bioactive molecules, including proteins. Here, we performed a comparative proteomic analysis of EVs secreted by A549 lung cancer cells and their cisplatin-resistant counterparts in order to identify proteins involved in drug resistance. Materials and Methods: Cells were co-cultivated using a transwell system to evaluate EV exchange. EVs were isolated by ultracentrifugation and analyzed using microscopy and nanoparticle tracking. EV proteome was analyzed by mass spectrometry. Results: EV-mediated communication was observed between co-cultured A549 and A549/CDDP cells. EVs isolated from both cells were mainly exosome-like structures. Extracellular matrix components, cell adhesion proteins, complement factors, histones, proteasome subunits and membrane transporters were found enriched in the EVs released by cisplatin-resistant cells. Conclusion: Proteins identified in this work may have a relevant role in modulating the chemosensitivity of the recipient cells and could represent useful biomarkers to monitor cisplatin response in lung cancer.Lung cancer is the most common cancer worldwide and the leading cause of cancer death in both men and women (1). Nonsmall cell lung cancer (NSCLC) is the most prevalent type of lung cancer, accounting for approximately 85% of all lung cancer cases (2). Most patients with NSCLC have non operable, advanced-stage disease at the time of diagnosis and platinumbased chemotherapy is the first-line treatment for these patients (3). However, the high incidence of tumor chemoresistance limits treatment success (4). Although numerous mechanisms have been associated with cisplatin (CDDP) resistance in lung cancer (5, 6), the cellular events within the tumor microenvironment that facilitate the acquisition and maintenance of chemoresistance are still poorly understood.Recently, extracellular vesicles (EVs) have emerged as key players for cell-cell communication in the tumor microenvironment (7). EVs are a heterogeneous group of membrane-bound structures secreted by cells into the extracellular space. Based on their size and biogenesis, EVs can be broadly classified into two main categories: exosomes and microvesicles (8). Exosomes are small membrane vesicles (30-100 nm in diameter) formed as intraluminal vesicles within endosomal multivesicular bodies (MVBs), and secreted upon the fusion of MVBs with the plasma membrane. Microvesicles (MVs) range in size from 50 nm to 1000 nm in diameter, but the cancer-derived MV population termed oncosomes can be much larger (up to 10 μm) (9). MVs are generated by the outward budding and fission of the plasma membrane.EVs mediate cellular crosstalk by transporting bioactive cargo between cells, including proteins, lipids, and nucleic acids (10). The EV cargo composition determine its biological effects and varies depending on the cell type and physiological/pathological state (11). In the tumor microenvironment, EVs have been shown to med...

Prostate cancer (PCa) is one of the most prevalent types of cancer in men worldwide; however, the main diagnostic tests available for PCa have limitations and a biopsy is required for histopathological confirmation of the disease. Prostate-specific antigen (PSA) is the main biomarker used for the early detection of PCa, but an elevated serum concentration is not cancer-specific. Therefore, there is a need for the discovery of new non-invasive biomarkers that can accurately diagnose PCa. The present study used trichloroacetic acid-induced protein precipitation and liquid chromatography-mass spectrometry to profile endogenous peptides in urine samples from patients with PCa (n=33), benign prostatic hyperplasia (n=25) and healthy individuals (n=28). Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of urinary peptides. In addition, Proteasix tool was used for in silico prediction of protease cleavage sites. Five urinary peptides derived from uromodulin were revealed to be significantly altered between the study groups, all of which were less abundant in the PCa group. This peptide panel showed a high potential to discriminate between the study groups, resulting in area under the curve (AUC) values between 0.788 and 0.951. In addition, urinary peptides outperformed PSA in discriminating between malignant and benign prostate conditions (AUC=0.847), showing high sensitivity (81.82%) and specificity (88%). From in silico analyses, the proteases HTRA2, KLK3, KLK4, KLK14 and MMP25 were identified as potentially involved in the degradation of uromodulin peptides in the urine of patients with PCa. In conclusion, the present study allowed the identification of urinary peptides with potential for use as non-invasive biomarkers in PCa diagnosis.

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