Extracellular vesicles from thyroid cancer harbor a functional machinery involved in extracellular matrix remodeling

Tumor-derived small extracellular vesicles facilitate omental metastasis of ovarian cancer by triggering activation of mesenchymal stem cells

BACKGROUND

Omental metastasis is the major cause of ovarian cancer recurrence and shortens patient survival, which can be largely attributed to the dynamic evolution of the fertile metastatic microenvironment driven by cancer cells. Previously, we found that adipose-derived mesenchymal stem cells (ADSCs) undergoing a phenotype shift toward cancer-associated fibroblasts (CAFs) participated in the orchestrated omental premetastatic niche for ovarian cancer. Here, we aim to elucidate the underlying mechanisms.

METHODS

Small extracellular vesicles were isolated from ovarian cancer cell lines (ES-2 and its highly metastatic subline, ES-2-HM) and patient ascites using ultracentrifugation. Functional experiments, including Transwell and EdU assays, and molecular detection, including Western blot, immunofluorescence, and RT-qPCR, were performed to investigate the activation of ADSCs in vitro. High-throughput transcriptional sequencing and functional assays were employed to identify the crucial functional molecules inducing CAF-like activation of ADSCs and the downstream effector of miR-320a. The impact of extracellular vesicles and miR-320a-activated ADSCs on tumor growth and metastasis was assessed in subcutaneous and orthotopic ovarian cancer xenograft mouse models. The expression of miR-320a in human samples was evaluated using in situ hybridization staining.

RESULTS

Primary human ADSCs cocultured with small extracellular vesicles, especially those derived from ES-2-HM, exhibited boosted migration, invasion, and proliferation capacities and elevated α-SMA and FAP levels. Tumor-derived small extracellular vesicles increased α-SMA-positive stromal cells, fostered omental metastasis, and shortened the survival of mice harboring orthotopic ovarian cancer xenografts. miR-320a was abundant in highly metastatic cell-derived extracellular vesicles, evoked dramatic CAF-like transition of ADSCs, targeted the 3'-untranslated region of integrin subunit alpha 7 and attenuated its expression. miR-320a overexpression in ovarian cancer was associated with omental metastasis and shorter survival. miR-320a-activated ADSCs facilitated tumor cell growth and omental metastasis. Depletion of integrin alpha 7 triggered CAF-like activation of ADSCs in vitro. Video Abstract CONCLUSIONS: miR-320a in small extracellular vesicles secreted by tumor cells targets integrin subunit alpha 7 in ADSCs and drives CAF-like activation, which in turn facilitates omental metastasis of ovarian cancer.

Tumor-associated macrophages as a potential therapeutic target in thyroid cancers

Macrophages are important precursor cell types of the innate immune system and bridge adaptive immune responses through the antigen presentation system. Meanwhile, macrophages constitute substantial portion of the stromal cells in the tumor microenvironment (TME) (referred to as tumor-associated macrophages, or TAMs) and exhibit conflicting roles in the development, invasion, and metastasis of thyroid cancer (TC). Moreover, TAMs play a crucial role to the behavior of TC due to their high degree of infiltration and prognostic relevance. Generally, TAMs can be divided into two subgroups; M1-like TAMs are capable of directly kill tumor cells, and recruiting and activating other immune cells in the early stages of cancer. However, due to changes in the TME, M2-like TAMs gradually increase and promote tumor progression. This review aims to discuss the impact of TAMs on TC, including their role in tumor promotion, gene mutation, and other factors related to the polarization of TAMs. Finally, we will explore the M2-like TAM-centered therapeutic strategies, including chemotherapy, clinical trials, and combinatorial immunotherapy.

Role of Extracellular Vesicles in Thyroid Physiology and Diseases: Implications for Diagnosis and Treatment

Extracellular vesicles are spherical subcellular structures delimited by a lipid bilayer and released by most cells in the human body. They are loaded with a myriad of molecules (i.e., nucleic acids and proteins) depending on their cell of origin and provide the ability to transmit a message to surrounding or distant target cells. In several organs, including the thyroid, abundant recent literature reports that extracellular vesicles are responsible for intercellular communication in physiological and pathological processes, and that their utilization as a potential biomarker of pathological states (i.e., cancer, autoimmune diseases) or as therapeutic delivery vehicles promise clinical options. In this review, we present the current knowledge and understanding regarding the role of extracellular vesicles in developing thyroid diseases and diagnosis.