Tetraspanins interweave EV secretion, endosomal network dynamics and cellular metabolism

Extracellular Vesicles in Breast Cancer: From Biology and Function to Clinical Diagnosis and Therapeutic Management

Breast cancer (BC) is the first worldwide most frequent cancer in both sexes and the most commonly diagnosed in females. Although BC mortality has been thoroughly declining over the past decades, there are still considerable differences between women diagnosed with early BC and when metastatic BC is diagnosed. BC treatment choice is widely dependent on precise histological and molecular characterization. However, recurrence or distant metastasis still occurs even with the most recent efficient therapies. Thus, a better understanding of the different factors underlying tumor escape is mainly mandatory. Among the leading candidates is the continuous interplay between tumor cells and their microenvironment, where extracellular vesicles play a significant role. Among extracellular vesicles, smaller ones, also called exosomes, can carry biomolecules, such as lipids, proteins, and nucleic acids, and generate signal transmission through an intercellular transfer of their content. This mechanism allows tumor cells to recruit and modify the adjacent and systemic microenvironment to support further invasion and dissemination. By reciprocity, stromal cells can also use exosomes to profoundly modify tumor cell behavior. This review intends to cover the most recent literature on the role of extracellular vesicle production in normal and cancerous breast tissues. Specific attention is paid to the use of extracellular vesicles for early BC diagnosis, follow-up, and prognosis because exosomes are actually under the spotlight of researchers as a high-potential source of liquid biopsies. Extracellular vesicles in BC treatment as new targets for therapy or efficient nanovectors to drive drug delivery are also summarized.

Extracellular vesicle distribution and localization in skeletal muscle at rest and following disuse atrophy

BACKGROUND

Skeletal muscle (SkM) is a large, secretory organ that produces and releases myokines that can have autocrine, paracrine, and endocrine effects. Whether extracellular vesicles (EVs) also play a role in the SkM adaptive response and ability to communicate with other tissues is not well understood. The purpose of this study was to investigate EV biogenesis factors, marker expression, and localization across cell types in the skeletal muscle. We also aimed to investigate whether EV concentrations are altered by disuse atrophy.

METHODS

To identify the potential markers of SkM-derived EVs, EVs were isolated from rat serum using density gradient ultracentrifugation, followed by fluorescence correlation spectroscopy measurements or qPCR. Single-cell RNA sequencing (scRNA-seq) data from rat SkM were analyzed to assess the EV biogenesis factor expression, and cellular localization of tetraspanins was investigated by immunohistochemistry. Finally, to assess the effects of mechanical unloading on EV expression in vivo, EV concentrations were measured in the serum by nanoparticle tracking analysis in both a rat and human model of disuse.

RESULTS

In this study, we show that the widely used markers of SkM-derived EVs, α-sarcoglycan and miR-1, are undetectable in serum EVs. We also found that EV biogenesis factors, including the tetraspanins CD63, CD9, and CD81, are expressed by a variety of cell types in SkM. SkM sections showed very low detection of CD63, CD9, and CD81 in myofibers and instead accumulation within the interstitial space. Furthermore, although there were no differences in serum EV concentrations following hindlimb suspension in rats, serum EV concentrations were elevated in human subjects after bed rest.

CONCLUSIONS

Our findings provide insight into the distribution and localization of EVs in SkM and demonstrate the importance of methodological guidelines in SkM EV research.

Potential diagnostic of lymph node metastasis and prognostic values of TM4SFs in papillary thyroid carcinoma patients

Background: Although the prognosis of papillary thyroid carcinoma (PTC) is relatively good, it causes around 41,000 deaths per year, which is likely related to recurrence and metastasis. Lymph node metastasis (LNM) is an important indicator of PTC recurrence and transmembrane 4 superfamily (TM4SF) proteins regulate metastasis by modulating cell adhesion, migration, tissue differentiation, and tumor invasion. However, the diagnostic and prognostic values of TM4SF in PTC remain unclear. Methods: This study aimed to identify TM4SF genes with predictive value for LNM and prognostic value in PTC using bioinformatic analysis. We screened the differentially expressed genes (DEGs) of the TM4SF family in PTC using data from TCGA, constructed a PPI network using STRING, and evaluated the predictive role of TM4SF1 in LNM via a binary logistic regression analysis and ROC curve. We assessed the association between TM4SF1 expression and DNA methylation, and determined the functional and mechanistic role of TM4SF1 in promoting LNM via GSEA, KEGG, and GO. We estimated the relationship between each TM4SF gene and overall survival (OS, estimated by Kaplan-Meier analysis) in patients with PTC and established a predictive model of prognostic indicators using a LASSO penalized Cox analysis to identify hub genes. Finally, we explored the correlation between TM4SFs and TMB/MSI. Results: We identified 21 DEGs from the 41 TM4SFs between N0 (without LNM) and N1 (with LNM) patients, with TM4SF1, TM4SF4, UPK1B, and CD151 being highly expressed in the N1 group; several DEGs were observed in the TNM, T, and N cancer stages. The "integrins and other cell-surface receptors" pathway was the most significantly enriched functional category related to LNM and TM4SFs. TM4SF1 was identified as an indicator of LNM (AUC= 0.702). High levels of TM4SF1 might be related to Wnt/β-catenin pathway and epithelial-mesenchymal transition (EMT) process in PTC. The higher expression of TM4SF1 was also related to DNA promoter hypomethylation. CD9, TM4SF4, TSPAN2, and TSPAN16 were associated with OS in PTC patients and TSPAN2 has great potential to become a prognostic marker of PTC progression. For the prognostic model, the riskscore = (-0.0058)*CD82+(-0.4994)*+(0.1584)*TSPAN11+(1.7597)*TSPAN19+(0.2694)*TSPAN2 (lambda.min = 0.0149). The AUCs for 3-year, 5-year, and 10-year OS were 0.81, 0.851, and 0.804. TSPAN18, TSPAN31, and TSPAN32 were associated with both TMB and MSI in PTC patients. Conclusion: Our findings identified TM4SF1 as a potential diagnostic marker of LNM and TSPAN2 as a prognostic factor for patients with PTC. Our study provides a novel strategy to assess prognosis and predict effective treatments in PTC.

TM4SF5-Mediated Regulation of Hepatocyte Transporters during Metabolic Liver Diseases

Nonalcoholic fatty liver disease (NAFLD) is found in up to 30% of the world’s population and can lead to hepatocellular carcinoma (HCC), which has a poor 5-year relative survival rate of less than 40%. Clinical therapeutic strategies are not very successful. The co-occurrence of metabolic disorders and inflammatory environments during the development of steatohepatitis thus needs to be more specifically diagnosed and treated to prevent fatal HCC development. To improve diagnostic and therapeutic strategies, the identification of molecules and/or pathways responsible for the initiation and progression of chronic liver disease has been explored in many studies, but further study is still required. Transmembrane 4 L six family member 5 (TM4SF5) has been observed to play roles in the regulation of metabolic functions and activities in hepatocytes using in vitro cell and in vivo animal models without or with TM4SF5 expression in addition to clinical liver tissue samples. TM4SF5 is present on the membranes of different organelles or vesicles and cooperates with transporters for fatty acids, amino acids, and monocarbohydrates, thus regulating nutrient uptake into hepatocytes and metabolism and leading to phenotypes of chronic liver diseases. In addition, TM4SF5 can remodel the immune environment by interacting with immune cells during TM4SF5-mediated chronic liver diseases. Because TM4SF5 may act as an NAFLD biomarker, this review summarizes crosstalk between TM4SF5 and nutrient transporters in hepatocytes, which is related to chronic liver diseases.