Extracellular vesicles of carcinoma-associated fibroblasts creates a pre-metastatic niche in the lung through activating fibroblasts.

OBJECTIVES: Carcinoma-associated fibroblasts (CAFs) have been known to promote cancer progression by modifying the primary tumor microenvironment. We aimed to elucidate the intercellular communication between CAFs and secondary organs in salivary adenoid cystic carcinoma (SACC) metastasis. METHODS: Pre-metastatic and metastatic animal models of SACC were established using extracellular vesicles (EVs) from CAFs and SACC cells. Lung fibroblasts (LFs) were treated with EVs and their transcriptomic alterations were identified by RNA sequencing. ITRAQ were performed to analyze EV cargos. TC I-15 was used to inhibit EV uptake by LFs and SACC lung metastasis in vivo. RESULTS: Here, we show that CAF EVs induced lung pre-metastatic niche formation in mice and consequently increased SACC lung metastasis. The pre-metastatic niche induced by CAF EVs was different from that induced by SACC EVs. CAF EVs presented a great ability for matrix remodeling and periostin is a potential biomarker characterizing the CAF EV-induced pre-metastatic niche. We found that lung fibroblast activation promoted by CAF EVs was a critical event at the pre-metastatic niche. Integrin α2ß1 mediated CAF EV uptake by lung fibroblasts, and its blockage by TC I-15 prevented lung pre-metastatic niche formation and subsequent metastasis. Plasma EV integrin ß1 was considerably upregulated in the mice bearing xenografts with high risk of lung metastasis. CONCLUSIONS: We demonstrated that CAF EVs participated in the pre-metastatic niche formation in the lung. Plasma EV integrin ß1 might be a promising biomarker to predict SACC metastasis at an early stage. An integrated strategy targeting both tumor and stromal cells is necessary to prevent SACC metastasis.

A Novel Tissue-Based Liver-Kidney-on-a-Chip Can Mimic Liver Tropism of Extracellular Vesicles Derived from Breast Cancer Cells.

Extracellular vesicles (EVs) from cancer cells remodel distant organs to promote metastasis in vivo. A biomimetic microsystem may compensate costly and time-consuming animal models to accelerate the study of EV organotropism. A tissue-based liver-kidney-on-a-chip is developed with precision-cut tissue slices (PTSs) cultured to represent individual organs. The organotropism of breast cancer EVs is modeled using the biomimetic microsystem. A traditional animal model of EV organotropism is used to investigate the physiological similarity of the microfluidic model to animal models. It is demonstrated that breast cancer EVs show strong liver tropism rather than kidney tropism on both the microfluidic and animal models. It is found that the metastatic inhibitor AMD3100 inhibits liver tropism effectively in both the microfluidic and animal models. Overall, the tropism of EVs to different organs is reconstituted on the microfluidic model. The liver-kidney-on-a-chip may expand the capabilities of traditional cell culture models and provide a faster alternative to animal models for EV studies.

Clinical application of a microfluidic chip for immunocapture and quantification of circulating exosomes to assist breast cancer diagnosis and molecular classification.

Increasing attention has been attracted by exosomes in blood-based diagnosis because cancer cells release more exosomes in serum than normal cells and these exosomes overexpress a certain number of cancer-related biomarkers. However, capture and biomarker analysis of exosomes for clinical application are technically challenging. In this study, we developed a microfluidic chip for immunocapture and quantification of circulating exosomes from small sample volume and applied this device in clinical study. Circulating EpCAM-positive exosomes were measured in 6 cases breast cancer patients and 3 healthy controls to assist diagnosis. A significant increase in the EpCAM-positive exosome level in these patients was detected, compared to healthy controls. Furthermore, we quantified circulating HER2-positive exosomes in 19 cases of breast cancer patients for molecular classification. We demonstrated that the exosomal HER2 expression levels were almost consistent with that in tumor tissues assessed by immunohistochemical staining. The microfluidic chip might provide a new platform to assist breast cancer diagnosis and molecular classification.