Most patients with ovarian cancer (OvCA) present peritoneal disseminated disease at the time of diagnosis. During peritoneal metastasis, cancer cells detach from the primary tumor and disseminate through the intraperitoneal fluid. The peritoneal mesothelial cell (PMC) monolayer that lines the abdominal cavity is the first barrier encountered by OvCA cells. Subsequent progression of tumors through the peritoneum leads to the accumulation into the peritoneal stroma of a sizeable population of carcinoma-associated fibroblasts (CAFs), which is mainly originated from a mesothelial-to-mesenchymal transition (MMT) process. A common characteristic of OvCA patients is the intraperitoneal accumulation of ascitic fluid, which is composed of cytokines, chemokines, growth factors, miRNAs, and proteins contained in exosomes, as well as tumor and mesothelial suspended cells, among other components that vary in proportion between patients. Exosomes are small extracellular vesicles that have been shown to mediate peritoneal metastasis by educating a pre-metastatic niche, promoting the accumulation of CAFs via MMT, and inducing tumor growth and chemoresistance. This review summarizes and discusses the pivotal role of exosomes and MMT as mediators of OvCA peritoneal colonization and as emerging diagnostic and therapeutic targets.

Mesothelial-to-Mesenchymal Transition and Exosomes in Peritoneal Metastasis of Ovarian Cancer

Ovarian cancer (OC) remains the leading cause of cancer-related death among gynecological cancers. The present study examined the role of collagen type V alpha 1 (COL5A1) and the characteristics of COL5A1 as an oncogenic protein in OC. The association of COL5A1 with paclitaxel (PTX)-resistance and stemness in OC was also studied and the multidatabase and big data analyses of the prognostic value, coexpression network, genetic alterations, and tumor-infiltrating immune cells of COL5A1 were elucidated. We found that COL5A1 expression was high in OC cells and tissues. Knockdown of COL5A1 inhibited the proliferation and migration of OC cells. Further study also showed that COL5A1 was overexpressed in PTX-resistant OC cells compared to respective PTX-sensitive cells. Additionally, COL5A1 was more enriched in OC stem cell-like cells. Silencing COL5A1 expression decreased the OC cell resistance to PTX and inhibited the ability of OC-spheroid formation. Survival analysis predicted that the elevated COL5A1 expression was associated with a worse survival outcome and correlated to the tumor stage of OC patients. The estimating relative subsets of RNA transcripts (CIBERSORT) algorithm analysis also unveiled the correlation of several tumor-infiltrating immune cells with the expression of COL5A1. Taken together, our data demonstrate that COL5A1 is a biomarker to predict OC progression and PTX-resistance and represents a promising target for OC treatment.

Overexpressed COL5A1 is correlated with tumor progression, paclitaxel resistance, and tumor-infiltrating immune cells in ovarian cancer.

Metastasis is the main culprit of cancer-associated mortality and involves a complex and multistage process termed the metastatic cascade, which requires tumor cells to detach from the primary site, intravasate, disseminate in the circulation, extravasate, adapt to the foreign microenvironment, and form organ-specific colonization. Each of these processes has been already studied extensively for molecular mechanisms focused mainly on protein-coding genes. Recently, increasing evidence is pointing towards RNAs without coding potential for proteins, referred to as non-coding RNAs, as regulators in shaping cellular activity. Since those first reports, the detection and characterization of non-coding RNA have explosively thrived and greatly enriched the understanding of the molecular regulatory networks in metastasis. Moreover, a comprehensive description of ncRNA dysregulation will provide new insights into novel tools for the early detection and treatment of metastatic cancer. In this review, we focus on discussion of the emerging role of ncRNAs in governing cancer metastasis and describe step by step how ncRNAs impinge on cancer metastasis. In particular, we highlight the diagnostic and therapeutic applications of ncRNAs in metastatic cancer.

Noncoding RNAs in tumor metastasis: molecular and clinical perspectives

Cervical cancer is the most prevalent gynecological malignancies accompanied by high mortality, where finding a more effective therapeutic option for cervical cancer is necessary. The inhibitory role of microRNAs (miRNAs) derived from the extracellular vesicles (EVs) of the bone marrow mesenchymal stem cells (BMSCs) was analyzed in cervical cancer. Expression of miR-375 was examined by RT-qPCR in cervical cancer cell lines. The targeting relation between miR-375 and maternal embryonic leucine zipper kinase (MELK) was predicted by bioinformatics analysis and verified by dual-luciferase reporter gene assay. Isolated BMSCs were transfected with lentivirus-mediated vectors, followed by EV extraction. The morphology of EVs was then identified using a NanoSight particle size analyzer and transmission electron microscope (TEM). The biological properties of cervical cancer cells were evaluated using Transwell, EdU, and TUNEL assays, respectively. Xenograft tumors in nude mice were observed to assess cervical tumorigenesis in vivo. Low expression of miR-375 and high expression of MELK were detected in cervical cancer samples. MELK was identified as the target gene of miR-375, which was negatively correlated with miR-375 levels. Overexpression of miR-375 suppressed proliferation, migration, and invasion of cervical cancer cells, but enhanced cell apoptosis by cooperating with downregulated MELK expression. miR-375 transferred from BMSC-derived EVs exerted the same effects on cell biological activities. Xenograft assays in vivo proved that miR-375 from BMSC-derived EVs inhibited tumor growth. The present study highlighted the role of miR-375 from BMSC-derived EVs in suppressing the progression of cervical cancer, which may contribute to the discovery of novel potential biomarkers for cervical cancer therapy.

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microRNA-375 released from extracellular vesicles of bone marrow mesenchymal stem cells exerts anti-oncogenic effects against cervical cancer.

Abstract Primary Sjögren’s syndrome (pSS) is a diffuse connective tissue disease characterized by the invasion of exocrine glands such as lacrimal and salivary glands, abnormal proliferation of T and B lymphocytes, and infiltration of tissue lymphocytes. With the development of modern medicine, although research on the pathogenesis, diagnosis, and treatment of pSS has made significant progress, its pathogenesis has not been fully understood. Meanwhile, in the era of individualized treatment, it remains essential to further explore early diagnosis and treatment methods. Exosomes, small vesicles containing proteins and nucleic acids, are a subtype of extracellular vesicles secreted by various cells and present in various body fluids. Exosomes contribute to a variety of biological functions, including intercellular signal transduction and pathophysiological processes, and may play a role in immune tolerance. Therefore, exosomes are key to understanding the pathogenesis of diseases. Exosomes can also be used as a therapeutic tool for pSS because of their biodegradability, low immunogenicity and toxicity, and the ability to bypass the blood–brain barrier, implying the prospect of a broad application in the context of pSS. Here, we systematically review the isolation, identification, tracing, and mode of action of extracellular vesicles, especially exosomes, as well as the research progress in the pathogenesis, diagnosis, and treatment of pSS. 

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Research status and future prospects of extracellular vesicles in primary Sjögren’s syndrome

Microenvironment remodeled by tumor and stromal cells elevates fibroblast-derived COL1A1 and facilitates ovarian cancer metastasis.

Metastasis is the key cause of death in ovarian cancer patients. To figure out the biological nature of cancer metastasis is essential for developing effective targeted therapy. Here we investigate how long non-coding RNA (lncRNA) SPOCD1-AS from ovarian cancer extracellular vesicles (EVs) remodel mesothelial cells through a mesothelial-to-mesenchymal transition (MMT) manner and facilitate peritoneal metastasis. EVs purified from ovarian cancer cells and ascites of patients were applied to mesothelial cells. The MMT process of mesothelial cells was assessed by morphology observation, western blot analysis, migration assay and adhesion assay. Altered lncRNAs of EV-treated mesothelial cells were screened by RNA sequencing and identified by qRT-PCR. SPOCD1-AS was overexpressed or silenced by overexpression lentivirus or shRNA, respectively. RNA pull-down and RNA immunoprecipitation assays were conducted to reveal the mechanism by which SPOCD1-AS remodeled mesothelial cells. Interfering peptides were synthesized and applied. Ovarian cancer orthotopic implantation mouse model was established in vivo. We found that ovarian cancer-secreted EVs could be taken into recipient mesothelial cells, induce the MMT phenotype and enhance cancer cell adhesion to mesothelial cells. Furthermore, SPOCD1-AS embedded in ovarian cancer-secreted EVs was transmitted to mesothelial cells to induce the MMT process and facilitate peritoneal colonization in vitro and in vivo. SPOCD1-AS induced the MMT process of mesothelial cells via interacting with G3BP1 protein. Additionally, G3BP1 interfering peptide based on the F380/F382 residues was able to block SPOCD1-AS/G3BP1 interaction, inhibit the MMT phenotype of mesothelial cells, and diminish peritoneal metastasis in vivo. Our findings elucidate the mechanism associated with EVs and their cargos in ovarian cancer peritoneal metastasis and may provide a potential approach for metastatic ovarian cancer therapeutics.

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LncRNA SPOCD1-AS from ovarian cancer extracellular vesicles remodels mesothelial cells to promote peritoneal metastasis via interacting with G3BP1.

Introduction Exosomal microRNA (miRNA) as a mediator of intercellular communication plays an essential part in tumor-relevant angiogenesis. Therapy against angiogenesis has been demonstrated to have a remarkable antitumor efficacy in various malignancies, but not as expected in ovarian cancer. Methods Exosomes were isolated by ultracentrifugation. Exosomal miRNA sequencing and gene function experiments were used to identify the differential expressed miRNAs in exosomes and their mRNA targets. SKOV3 cell line that stably overexpressed miR-92b-3p was constructed by lentivirus. In vitro, angiogenesis was analyzed by tube formation assay and migration assay. The angiogenic and antitumor effects in vivo were assessed in zebrafish and nude mouse models. Combination index was calculated to assess the synergetic inhibition of angiogenesis between miR-92b-3p and Apatinib. Peptides were conjugated with exosomal membranes to obtain engineered exosomes. Results Ovarian cancer cell-derived exosomes facilitated the angiogenesis and migration capability of vascular endothelial cells in vitro and in vivo. The expression of miR-92b-3p was much lower in ovarian cancer cell-derived exosomes than that in immortalized ovarian epithelial cell-derived exosomes. The exosomal miR-92b-3p modulated tumor-associated angiogenesis via targeting SOX4. Besides, Peptide-engineered exosomes with overexpressed miR-92b-3p showed the stronger abilities of anti-angiogenesis and antitumor than parental exosomes, whether alone or combined with Apatinib. Conclusions Our findings demonstrate the effect and mechanism of exosomal miR-92b-3p from ovarian cancer cells on tumor-associated angiogenesis and the potential of artificially generated exosomes with overexpressed miR-92b-3p to be used as anti-angiogenic agent, which may provide a new approach for anti-angiogenic therapy of ovarian cancer.

Potential of peptide-engineered exosomes with overexpressed miR-92b-3p in anti-angiogenic therapy of ovarian cancer.

The prognosis of advanced stage cervical cancer is poorer due to cancer invasion and metastasis. Exploring new factors and signalling pathways associated with invasiveness and metastasis would help to identify new therapeutic targets for advanced cervical cancer. We searched the cancer microarray database, Oncomine, and found elevated calponin 3 (CNN3) mRNA expression in cervical cancer tissues. QRT-PCR verified the increased CNN3 expression in cervical cancer compared to para-cancer tissues. Proliferation, migration and invasion assays showed that overexpressed CNN3 promoted the viability and motility of cervical cancer cells, the opposite was observed in CNN3-knockdown cells. In addition, xenografted tumours, established from SiHa cells with CNN3 knockdown, displayed decreased growth and metastasis in vivo. Furthermore, RNA-sequencing showed that ribosomal protein lateral stalk subunit P1 (RPLP1) was a potential downstream gene. Gene function experiments revealed that RPLP1 had the same biological effects as CNN3 did. Rescue experiments demonstrated that the phenotypes inhibited by CNN3 silencing were partly or completely reversed by RPLP1 overexpression. In conclusion, we verified that CNN3 acts as an oncogene to promote the viability and motility of cervical cancer cells in vitro and accelerate the growth and metastasis of xenografted tumours in vivo, by affecting RPLP1 expression.

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Mingyue Li

Papers

Microenvironment remodeled by tumor and stromal cells elevates fibroblast-derived COL1A1 and facilitates ovarian cancer metastasis.

LncRNA SPOCD1-AS from ovarian cancer extracellular vesicles remodels mesothelial cells to promote peritoneal metastasis via interacting with G3BP1.

Potential of peptide-engineered exosomes with overexpressed miR-92b-3p in anti-angiogenic therapy of ovarian cancer.

CNN3 acts as a potential oncogene in cervical cancer by affecting RPLP1 mRNA expression