Periostin and Epithelial-Mesenchymal Transition Score as Novel Prognostic Markers for Leiomyosarcoma, Myxofibrosarcoma, and Undifferentiated Pleomorphic Sarcoma

Establishment and characterization of the novel myxofibrosarcoma cell line, SMU-MFS

Myxofibrosarcoma (MFS) is one of the most common soft-tissue sarcomas in elderly patients. Owing to the limited efficacy of chemotherapy and radiotherapy, complete resection is the only available curative treatment. Therefore, developing novel therapies for MFS is important to improve clinical outcomes. Herein, a novel MFS cell line, namely SMU-MFS, was established to better understand the biologic characteristics of MFS and develop new therapies. A tissue sample from the surgically resected tumor tissue of a 56-year-old patient with a tumor was subjected to primary culture. The cell line was established and authenticated by assessing the short tandem repeats of DNA microsatellites. The monolayer cultures of SMU-MFS cells exhibited constant growth, spheroid formation, and invasive capacity. Furthermore, the cells exhibited low chemosensitivity to doxorubicin, eribulin, and pazopanib, which are used to inhibit metastatic progression. In addition, of the four mice inoculated with SMU-MFS cells, tumors developed in two mice after 8 weeks. Altogether, the findings of this study suggest that the SMU-MFS cell line can be a useful tool for investigating MFS development and evaluating novel therapeutic agents.

Decoding Chemotherapy Resistance of Undifferentiated Pleomorphic Sarcoma at the Single Cell Resolution: A Case Report

Background: Undifferentiated pleomorphic sarcoma (UPS) is a highly malignant mesenchymal tumor that ranks as one of the most common types of soft tissue sarcoma. Even though chemotherapy increases the 5-year survival rate in UPS, high tumor heterogeneity frequently leads to chemotherapy resistance and consequently to recurrences. In this study, we characterized the cell composition and the transcriptional profile of UPS with resistance to chemotherapy at the single cell resolution. Methods: A 58-year-old woman was diagnosed with a 13.6 × 9.3 × 6.0 cm multi-nodular tumor with heterogeneous cysto-solid structure at the level of the distal metadiaphysis of the left thigh during magnetic resonance tomography. Morphological and immunohistochemical analysis led to the diagnosis of high-grade (G3) UPS. Neoadjuvant chemotherapy, surgery (negative resection margins), and adjuvant chemotherapy were conducted, but tumor recurrence developed. The UPS sample was used to perform single-cell RNA sequencing by chromium-fixed RNA profiling. Results: Four subpopulations of tumor cells and seven subpopulations of tumor microenvironment (TME) have been identified in UPS. The expression of chemoresistance genes has been detected, including KLF4 (doxorubicin and ifosfamide), ULK1, LUM, GPNMB, and CAVIN1 (doxorubicin), and AHNAK2 (gemcitabine) in tumor cells and ETS1 (gemcitabine) in TME. Conclusions: This study provides the first description of the single-cell transcriptome of UPS with resistance to two lines of chemotherapy, showcasing the gene expression in subpopulations of tumor cells and TME, which may be potential markers for personalized cancer therapy.

Modeling Myxofibrosarcoma: Where Do We Stand and What Is Missing?

Myxofibrosarcoma (MFS) is a malignant soft tissue sarcoma (STS) that originates in the body's connective tissues. It is characterized by the presence of myxoid (gel-like) and fibrous components and typically affects patients after the fifth decade of life. Considering the ongoing trend of increasing lifespans across many nations, MFS is likely to become the most common musculoskeletal sarcoma in the future. Although MFS patients have a lower risk of developing distant metastases compared with other STS cases, MFS is characterized by a high frequency of local recurrence. Notably, in 40-60% of the patients where the tumor recurs, it does so multiple times. Consequently, patients may undergo multiple local surgeries, removing the risk of potential amputation. Furthermore, because the tumor relapses generally have a higher grade, they exhibit a decreased response to radio and chemotherapy and an increased tendency to form metastases. Thus, a better understanding of MFS is required, and improved therapeutic options must be developed. Historically, preclinical models for other types of tumors have been instrumental in obtaining a better understanding of tumor development and in testing new therapeutic approaches. However, few MFS models are currently available. In this review, we will describe the MFS models available and will provide insights into the advantages and constraints of each model.

Extracellular vesicle-circEHD2 promotes the progression of renal cell carcinoma by activating cancer-associated fibroblasts

BACKGROUND

The encapsulation of circular RNAs (circRNAs) into extracellular vesicles (EVs) enables their involvement in intercellular communication and exerts an influence on the malignant advancement of various tumors. However, the regulatory role of EVs-circRNA in renal cell carcinoma (RCC) remains elusive.

METHODS

The in vitro and in vivo functional experiments were implemented to measure the effects of circEHD2 on the phenotype of RCC. The functional role of EVs-circEHD2 on the activation of fibroblasts was assessed by collagen contraction assay, western blotting, and enzyme-linked immunosorbent assay (ELISA). The mechanism was investigated by RNA pull-down assay, RNA immunoprecipitation, chromatin isolation by RNA purification, luciferase assay, and co-immunoprecipitation assay.

RESULTS

We demonstrated that circEHD2 was upregulated in RCC tissues and serum EVs of RCC patients with metastasis. Silencing circEHD2 inhibited tumor growth in vitro and in vivo. Mechanistic studies indicated that FUS RNA -binding protein (FUS) accelerated the cyclization of circEHD2, then circEHD2 interacts with tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein eta (YWHAH), which acts as a bridge to recruit circEHD2 and Yes1-associated transcriptional regulator (YAP) to the promoter of SRY-box transcription factor 9 (SOX9); this results in the sustained activation of SOX9. Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2B1) regulates the package of circEHD2 into EVs, then EVs-circEHD2 transmits to fibroblasts, converting fibroblasts to cancer-associated fibroblasts (CAFs). Activated CAFs promote the metastasis of RCC by secreting pro-inflammatory cytokines such as IL-6. Furthermore, antisense oligonucleotides (ASOs) targeting circEHD2 exhibited a strong inhibition of tumor growth in vivo.

CONCLUSIONS

The circEHD2/YWHAH/YAP/SOX9 signaling pathway accelerates the growth of RCC. EVs-circEHD2 facilitates the metastasis of RCC by converting fibroblasts to CAFs. Our results suggest that EVs-circEHD2 may be a useful biomarker and therapeutic target for RCC.

Periostin: biology and function in cancer

Periostin (POSTN), a member of the matricellular protein family, is a secreted adhesion-related protein produced in the periosteum and periodontal ligaments. Matricellular proteins are a nonstructural family of extracellular matrix (ECM) proteins that regulate a wide range of biological processes in both normal and pathological conditions. Recent studies have demonstrated the key roles of these ECM proteins in the tumor microenvironment. Furthermore, periostin is an essential regulator of bone and tooth formation and maintenance, as well as cardiac development. Also, periostin interacts with multiple cell-surface receptors, especially integrins, and triggers signals that promote tumor growth. According to recent studies, these signals are implicated in cancer cell survival, epithelial-mesenchymal transition (EMT), invasion, and metastasis. In this review, we will summarize the most current data regarding periostin, its structure and isoforms, expressions, functions, and regulation in normal and cancerous tissues. Emphasis is placed on its association with cancer progression, and also future potential for periostin-targeted therapeutic approaches will be explored.

CircSCAF8 promotes growth and metastasis of prostate cancer through the circSCAF8-miR-140-3p/miR-335-LIF pathway

Circular RNAs (circRNAs) have been increasingly linked to cancer progression. However, the detailed biological functions of circRNAs in prostate cancer (PCa) remain unclear. Using high-throughput circRNA sequencing, we previously identified 18 urine extracellular vesicle circRNAs that were increased in patients with PCa compared with those with benign prostatic hyperplasia. Spearman correlation analysis of the expression levels of the 18 circRNAs between the tumor tissue and matched urine extracellular vesicles in 30 PCa patients showed that circSCAF8 had the highest R² (R² = 0.635, P < 0.001). The Cox proportional hazards regression model was used to estimate the effect of circSCAF8 on progression-free survival. The in vitro and in vivo functional experiments were implemented to investigate the effects of circSCAF8 on the phenotype of PCa. We found that the knockdown of circSCAF8 in PCa cells suppressed the proliferation, migration, and invasion ability, while overexpression of circSCAF8 had the opposite effects. Similar results were observed in vivo. In a cohort of 85 patients who had undergone radical prostatectomy, circSCAF8 expression in PCa tissues was a powerful predictor of progression-free survival (HR = 2.14, P = 0.022). Mechanistically, circSCAF8 can function by binding to both miR-140-3p and miR-335 to regulate LIF expression and activate the LIF-STAT3 pathway that leads to the growth and metastasis of PCa. Collectively, our findings demonstrate that circSCAF8 contributes to PCa progression through the circSCAF8-miR-140-3p/miR-335-LIF pathway.

Mechanisms Involved in the Promoting Activity of Fibroblasts in HTLV-1-Mediated Lymphomagenesis: Insights into the Plasticity of Lymphomatous Cells

Among the mechanisms leading to progression to Adult T-cell Leukaemia/Lymphoma in Human T-cell Leukaemia Virus type 1 (HTLV-1)-infected subjects, the contribution of stromal components remains poorly understood. To dissect the role of fibroblasts in HTLV-1-mediated lymphomagenesis, transcriptome studies, cytofluorimetric and qRT-PCR analyses of surface and intracellular markers linked to plasticity and stemness in coculture, and in vivo experiments were performed. A transcriptomic comparison between a more lymphomagenic (C91/III) and the parental (C91/PL) cell line evidenced hyperactivation of the PI3K/Akt pathway, confirmed by phospho-ELISA and 2-DE and WB analyses. C91/III cells also showed higher expression of mesenchymal and stemness genes. Short-term coculture with human foreskin fibroblasts (HFF) induced these features in C91/PL cells, and significantly increased not only the cancer stem cells (CSCs)-supporting CD10+GPR77+ HFF subpopulation, but also the percentage of ALDH1bright C91/PL cells. A non-cytotoxic acetylsalicylic acid treatment decreased HFF-induced ALDH1bright C91/PL cells, downregulated mesenchymal and stemness genes in cocultured cells, and delayed lymphoma growth in immunosuppressed mice, thus hindering the supportive activity of HFF on CSCs. These data suggest that crosstalk with HFF significantly intensifies the aggressiveness and plasticity of C91/PL cells, leading to the enrichment in lymphoma-initiating cells. Additional research is needed to better characterize these preliminary findings.

Periostin in Allergy and Inflammation

Matricellular proteins are involved in the crosstalk between cells and their environment and thus play an important role in allergic and inflammatory reactions. Periostin, a matricellular protein, has several documented and multi-faceted roles in health and disease. It is differentially expressed, usually upregulated, in allergic conditions, a variety of inflammatory diseases as well as in cancer and contributes to the development and progression of these diseases. Periostin has also been shown to influence tissue remodelling, fibrosis, regeneration and repair. In allergic reactions periostin is involved in type 2 immunity and can be induced by IL-4 and IL-13 in bronchial cells. A variety of different allergic diseases, among them bronchial asthma and atopic dermatitis (AD), have been shown to be connected to periostin expression. Periostin is commonly expressed in fibroblasts and acts on epithelial cells as well as fibroblasts involving integrin and NF-κB signalling. Also direct signalling between periostin and immune cells has been reported. The deposition of periostin in inflamed, often fibrotic, tissues is further fuelling the inflammatory process. There is increasing evidence that periostin is also expressed by epithelial cells in several of the above-mentioned conditions as well as in cancer. Augmented periostin expression has also been associated with chronic inflammation such as in inflammatory bowel disease (IBD). Periostin can be expressed in a variety of different isoforms, whose functions have not been elucidated yet. This review will discuss potential functions of periostin and its different isoforms in allergy and inflammation.

Prognostic value of CD34 expression status in patients with myxofibrosarcomas and undifferentiated pleomorphic sarcomas

It is controversial whether patients with myxofibrosarcomas (MFSs) have better prognoses than those with undifferentiated pleomorphic sarcomas (UPSs). No useful prognostic factors have been established to date. We therefore aimed to evaluate the prognostic value of CD34 expression status in 192 patients with MFSs and UPSs. Using the log-rank test, we showed that patients with MFSs had a significantly better overall survival than did those with UPSs when defining the former as having a > 10% myxoid component (p = 0.03), but not when defining it as having a > 50% myxoid component (p = 0.1). Under the definition of MFSs as > 10% myxoid component, the log-rank test revealed that the diagnosis of the UPS and the CD34 loss (p < 0.001) were significant adverse predictors of overall survival. As per the Cox model, the CD34 loss remained an independent prognostic factor (hazard ratio = 3.327; 95% confidence interval 1.334-8.295), while the diagnosis of the UPS was a nonsignificant confounding factor (hazard ratio = 1.084; 95% confidence interval 0.679-1.727). In conclusion, CD34 expression status is a useful prognostic factor in patients with MFS and UPS, and it should be incorporated into grading systems that are used to predict outcomes.

Role of Epithelial-Mesenchymal Plasticity in Pseudomyxoma Peritonei: Implications for Locoregional Treatments

The mechanisms by which neoplastic cells disseminate from the primary tumor to metastatic sites, so-called metastatic organotropism, remain poorly understood. Epithelial-mesenchymal transition (EMT) plays a role in cancer development and progression by converting static epithelial cells into the migratory and microenvironment-interacting mesenchymal cells, and by the modulation of chemoresistance and stemness of tumor cells. Several findings highlight that pathways involved in EMT and its reverse process (mesenchymal-epithelial transition, MET), now collectively called epithelial-mesenchymal plasticity (EMP), play a role in peritoneal metastases. So far, the relevance of factors linked to EMP in a unique peritoneal malignancy such as pseudomyxoma peritonei (PMP) has not been fully elucidated. In this review, we focus on the role of epithelial-mesenchymal dynamics in the metastatic process involving mucinous neoplastic dissemination in the peritoneum. In particular, we discuss the role of expression profiles and phenotypic transitions found in PMP in light of the recent concept of EMP. A better understanding of EMP-associated mechanisms driving peritoneal metastasis will help to provide a more targeted approach for PMP patients selected for locoregional interventions involving cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.