Filopodia play an important role in the trans-mesothelial migration of ovarian cancer cells

Tumor microenvironment: A playground for cells from multiple diverse origins

Tumor microenvironment is formed by various cellular and non-cellular components which interact with one another and form a complex network of interactions. Some of these cellular components also attain a secretory phenotype and release growth factors, cytokines, chemokines etc. in the surroundings which are capable of inducing even greater number of signalling networks. All these interactions play a decisive role in determining the course of tumorigenesis. The treatment strategies against cancer also exert their impact on the local microenvironment. Such interactions and anticancer therapies have been found to induce more deleterious outcomes like immunosuppression and chemoresistance in the process of tumor progression. Hence, understanding the tumor microenvironment is crucial for dealing with cancer and chemoresistance. This review is an attempt to develop some understanding about the tumor microenvironment and different factors which modulate it, thereby contributing to tumorigenesis. Along with summarising the major components of tumor microenvironment and various interactions taking place between them, it also throws some light on how the existing and potential therapies exert their impact on these dynamics.

Ovarian cancer: Novel mechanisms and therapeutic targets regarding the microenvironment in the abdominal cavity

Ovarian cancer is an intractable disease that is mostly diagnosed at an advanced stage and has a high recurrence rate. The early development of characteristic peritoneal dissemination via ascites contributes to a poor prognosis. Based on the "seed and soil" theory, ovarian cancer is considered to form a disseminated tumor that interacts with the peritoneum; superficial mesothelial cells are structurally important. Thus far, we have reported that peritoneal mesothelial cells, which originally are ecological defenses, transform into ovarian cancer-associated mesothelial cells, which are allies of cancer. They are found to be actively involved in the formation of a friendly "soil" that promotes the survival of "seeds" of ovarian cancer cells. We also demonstrated that the progression of ovarian cancer and the induction of its refractory nature are partially mediated through competition and cooperation between ovarian cancer and mesothelial cells. We believe that it is necessary to shift the aim of treatment strategies from solely targeting cancer cells to focusing on the crosstalk between the surrounding environment and ovarian cancer, an approach that ultimately aims to achieve "coexistence" with cancer through disease control.

Polyploidy, EZH2 upregulation, and transformation in cytomegalovirus-infected human ovarian epithelial cells

Human cytomegalovirus (HCMV) infection has been implicated in epithelial ovarian cancer (OC). Polyploidy giant cancer cells (PGCCs) have been observed in high-grade serous ovarian carcinoma (HGSOC); they possess cancer stem cell-like characteristics and give rise to progeny cells expressing epithelial-mesenchymal transition (EMT) markers. EZH2 plays a potential oncogenic role, correlating with high proliferative index and tumor grade in OC. Herein, we present the experimental evidence for HCMV as a reprogramming vector that elicited human ovarian epithelial cells (OECs) transformation leading to the generation of "CMV-transformed Ovarian cells" (CTO). The infection with the two high-risk clinical strains, namely HCMV-DB and BL provoked a distinct cellular and molecular mechanisms in infected OECs. EZH2 upregulation and cellular proliferation were curtailed by using EZH2 inhibitors. The HGSOC biopsies were characterized by an elevated EZH2 expression, possessing a strong positive correlation between the aforementioned marker and HCMV. From HGSOC biopsies, we isolated three HCMV clinical strains that transformed OECs generating CTO cells which displayed proliferative potentials in addition to EZH2 upregulation and PGCCs generation; these features were reduced upon EZH2 inhibition. High-risk HCMV strains transformed OECs confirming an HCMV-induced epithelial ovarian cancer model and highlighting EZH2 tumorigenic properties. Our findings might be highly relevant in the pathophysiology of ovarian tumors thereby nominating new targeted therapeutics.

Peristalsis-Associated Mechanotransduction Drives Malignant Progression of Colorectal Cancer

Introduction

In the colorectal cancer (CRC) tumor microenvironment, cancerous and precancerous cells continuously experience mechanical forces associated with peristalsis. Given that mechanical forces like shear stress and strain can positively impact cancer progression, we explored the hypothesis that peristalsis may also contribute to malignant progression in CRC. We defined malignant progression as enrichment of cancer stem cells and the acquisition of invasive behaviors, both vital to CRC progression.

Methods

We leveraged our peristalsis bioreactor to expose CRC cell lines (HCT116), patient-derived xenograft (PDX1,2) lines, or non-cancerous intestinal cells (HIEC-6) to forces associated with peristalsis in vitro. Cells were maintained in static control conditions or exposed to peristalsis for 24 h prior to assessment of cancer stem cell (CSC) emergence or the acquisition of invasive phenotypes.

Results

Exposure of HCT116 cells to peristalsis significantly increased the emergence of LGR5+ CSCs by 1.8-fold compared to static controls. Peristalsis enriched LGR5 positivity in several CRC cell lines, notably significant in KRAS mutant lines. In contrast, peristalsis failed to increase LGR5+ in non-cancerous intestinal cells, HIEC-6. LGR5+ emergence downstream of peristalsis was dependent on ROCK and Wnt activity, and not YAP1 activation. Additionally, HCT116 cells adopted invasive morphologies when exposed to peristalsis, with increased filopodia density and epithelial to mesenchymal gene expression, in a Wnt dependent manner.

Conclusions

Peristalsis associated forces drive malignant progression of CRC via ROCK, YAP1, and Wnt-related mechanotransduction.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-023-00776-w.

Fascin-1 in Cancer Cell Metastasis: Old Target-New Insights

As metastasis is responsible for most cancer-related deaths, understanding the cellular and molecular events that lead to cancer cell migration and invasion will certainly provide insights into novel anti-metastatic therapeutic targets. Fascin-1 is an actin-bundling protein fundamental to all physiological or pathological processes that require cell migration. It is responsible for cross-linking actin microfilaments during the formation of actin-rich cellular structures at the leading edge of migrating cells such as filopodia, lamellipodia and invadopodia. While most epithelial tissues express low levels of Fascin-1, it is dramatically elevated in the majority of cancers and its expression has been associated with more aggressive disease and decreased overall survival. Hence, it has been proposed as a potential anti-cancer target. In the present review, we studied recent literature with regard to Fascin-1 expression in different cancers, its role in altering the mechanical properties of cancer cells, promoting cancer cell migration, invasion and metastasis and the effect of its inhibition, via various pharmacological inhibitors, in eliminating metastasis in vitro and/or in vivo. Recent studies corroborate the notion that Fascin-1 is critically involved in metastasis and prove that it is a valuable anti-metastatic target that is worth investigating further.

Antimetastatic Properties of Prodigiosin and the BH3-Mimetic Obatoclax (GX15-070) in Melanoma

Metastasis is the primary cause of death in cancer patients. Many current chemotherapeutic agents only show cytotoxic, but not antimetastatic properties. This leads to a reduction in tumor size, but allows cancer cells to disseminate, which ultimately causes patient death. Therefore, novel anticancer compounds with both effects need to be developed. In this work, we analyze the antimetastatic properties of prodigiosin and obatoclax (GX15-070), anticancer drugs of the Prodiginines (PGs) family. We studied PGs' effects on cellular adhesion and morphology in the human primary and metastatic melanoma cell lines, SK-MEL-28 and SK-MEL-5, and in the murine melanoma cell line, B16F10A. Cell adhesion sharply decreased in the treated cells, and this was accompanied by a reduction in filopodia protrusions and a significant decrease in the number of focal-adhesion structures. Moreover, cell migration was assessed through the wound-healing assay and cell motility was severely inhibited after 24 h of treatment. To elucidate the molecular mechanisms involved, changes in metastasis-related genes were analyzed through a gene-expression array. Key genes related to cellular invasion, migration and chemoresistance were significantly down-regulated. Finally, an in vivo model of melanoma-induced lung metastasis was established and significant differences in lung tumors were observed in the obatoclax-treated mice. Altogether, these results describe, in depth, PGs' cellular antimetastatic effects and identify in vivo antimetastatic properties of Obatoclax.

Polarity switching of ovarian cancer cell clusters via SRC family kinase is involved in the peritoneal dissemination

Peritoneal dissemination is a predominant pattern of metastasis in patients with advanced ovarian cancer. Despite recent progress in the management strategy, peritoneal dissemination remains a determinant of poor ovarian cancer prognosis. Using various histological types of patient‐derived ovarian cancer organoids, the roles of the apicobasal polarity of ovarian cancer cell clusters in peritoneal dissemination were studied. First, it was found that both ovarian cancer tissues and ovarian organoids showed apicobasal polarity, where zonula occludens‐1 (ZO‐1) and integrin beta 4 (ITGB4) served as markers for apical and basal sides, respectively. The organoids in suspension culture, as a model of cancer cell cluster floating in ascites, showed apical‐out/basal‐in polarity status, while once embedded in extracellular matrix (ECM), the organoids switched their polarity to apical‐in/basal‐out. This polarity switch was accompanied by the SRC kinase family (SFK) phosphorylation and was inhibited by SFK inhibitors. SFK inhibitors abrogated the adherence of the organoids onto the ECM‐coated plastic surface. When the organoids were seeded on a mesothelial cell layer, they cleared and invaded mesothelial cells. In vivo, dasatinib, an SFK inhibitor, suppressed peritoneal dissemination of ovarian cancer organoids in immunodeficient mice. These results suggest SFK‐mediated polarity switching is involved in peritoneal metastasis. Polarity switching would be a potential therapeutic target for suppressing peritoneal dissemination in ovarian cancer.

Metastatic Voyage of Ovarian Cancer Cells in Ascites with the Assistance of Various Cellular Components

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy and has a unique metastatic route using ascites, known as the transcoelomic root. However, studies on ascites and contained cellular components have not yet been sufficiently clarified. In this review, we focus on the significance of accumulating ascites, contained EOC cells in the form of spheroids, and interaction with non-malignant host cells. To become resistant against anoikis, EOC cells form spheroids in ascites, where epithelial-to-mesenchymal transition stimulated by transforming growth factor-β can be a key pathway. As spheroids form, EOC cells are also gaining the ability to attach and invade the peritoneum to induce intraperitoneal metastasis, as well as resistance to conventional chemotherapy. Recently, accumulating evidence suggests that EOC spheroids in ascites are composed of not only cancer cells, but also non-malignant cells existing with higher abundance than EOC cells in ascites, including macrophages, mesothelial cells, and lymphocytes. Moreover, hetero-cellular spheroids are demonstrated to form more aggregated spheroids and have higher adhesion ability for the mesothelial layer. To improve the poor prognosis, we need to elucidate the mechanisms of spheroid formation and interactions with non-malignant cells in ascites that are a unique tumor microenvironment for EOC.

Peritoneal Restoration by Repurposing Vitamin D Inhibits Ovarian Cancer Dissemination via Blockade of the TGF-β1/Thrombospondin-1 Axis

PURPOSE

Ovarian cancer (OvCa), a lethal gynecological malignancy, disseminates to the peritoneum. Mesothelial cells (MCs) act as barriers in the abdominal cavity, preventing the adhesion of cancer cells. However, in patients with OvCa, they are transformed into cancer-associated mesothelial cells (CAMs) via mesenchymal transition and form a favorable microenvironment for tumors to promote metastasis. However, attempts for restoring CAMs to their original state have been limited. Here, we investigated whether inhibition of mesenchymal transition and restoration of MCs by vitamin D suppressed the OvCa dissemination in vitro and in vivo.

METHODS

The effect of vitamin D on the mutual association of MCs and OvCa cells was evaluated using in vitro coculture models and in vivo using a xenograft model.

RESULTS

Vitamin D restored the CAMs, and thrombospondin-1 (component of the extracellular matrix that is clinically associated with poor prognosis and is highly expressed in peritoneally metastasized OvCa) was found to promote OvCa cell adhesion and proliferation. Mechanistically, TGF-β1 secreted from OvCa cells enhanced thrombospondin-1 expression in CAMs via Smad-dependent TGF-β signaling. Vitamin D inhibited mesenchymal transition in MCs and suppressed thrombospondin-1 expression via vitamin D receptor/Smad3 competition, contributing to the marked reduction in peritoneal dissemination in vivo. Importantly, vitamin D restored CAMs from a stabilized mesenchymal state to the epithelial state and normalized thrombospondin-1 expression in preclinical models that mimic cancerous peritonitis in vivo.

CONCLUSIONS

MCs are key players in OvCa dissemination and peritoneal restoration and normalization of thrombospondin-1 expression by vitamin D may be a novel strategy for preventing OvCa dissemination.

Fascin-1: Updated biological functions and therapeutic implications in cancer biology

Filopodia are cellular protrusions that respond to a variety of stimuli. Filopodia are formed when actin is bound to the protein Fascin, which may play a crucial role in cellular interactions and motility during cancer metastasis. Significantly, the noncanonical features of Fascin-1 are gradually being clarified, including the related molecular network contributing to metabolic reprogramming, chemotherapy resistance, stemness ac-tivity, and tumor microenvironment events. However, the relationship between biological characteristics and pathological features to identify effective therapeutic strategies needs to be studied further. The pur-pose of this review article is to provide a broad overview of the latest molecular networks and multiomics research regarding fascins and cancer. It also highlights their direct and indirect effects on available cancer treatments. With this multidisciplinary approach, researchers and clinicians can gain the most relevant in-formation on the function of fascins in cancer progression, which may facilitate clinical applications in the future.

The Transcoelomic Ecosystem and Epithelial Ovarian Cancer Dissemination

Epithelial ovarian cancer (EOC) is considered the deadliest gynecological disease and is normally diagnosed at late stages, at which point metastasis has already occurred. Throughout disease progression, EOC will encounter various ecosystems and the communication between cancer cells and these microenvironments will promote the survival and dissemination of EOC. The primary tumor is thought to develop within the ovaries or the fallopian tubes, both of which provide a microenvironment with high risk of causing DNA damage and enhanced proliferation. EOC disseminates by direct extension from the primary tumors, as single cells or multicellular aggregates. Under the influence of cellular and non-cellular factors, EOC spheroids use the natural flow of peritoneal fluid to reach distant organs within the peritoneal cavity. These cells can then implant and seed distant organs or tissues, which develop rapidly into secondary tumor nodules. The peritoneal tissue and the omentum are two common sites of EOC metastasis, providing a microenvironment that supports EOC invasion and survival. Current treatment for EOC involves debulking surgery followed by platinum-taxane combination chemotherapy; however, most patients will relapse with a chemoresistant disease with tumors developed within the peritoneum. Therefore, understanding the role of the unique microenvironments that promote EOC transcoelomic dissemination is important in improving patient outcomes from this disease. In this review article, we address the process of ovarian cancer cellular fate at the site of its origin in the secretory cells of the fallopian tube or in the ovarian surface epithelial cells, their detachment process, how the cells survive in the peritoneal fluid avoiding cell death triggers, and how cancer- associated cells help them in the process. Finally, we report the mechanisms used by the ovarian cancer cells to adhere and migrate through the mesothelial monolayer lining the peritoneum. We also discuss the involvement of the transcoelomic ecosystem on the development of chemoresistance of EOC.

Fascin in Gynecological Cancers: An Update of the Literature

Simple Summary

Fascin, an actin-binding protein, is upregulated in different types of human cancers. It is reportedly responsible for increasing the invasive and metastatic ability of cancer cells by reducing cell–cell adhesions. This review provides a brief overview of fascin and its interactions with other genes and oncoviruses to induce the onset and progression of cancer.

Abstract

Fascin is an actin-binding protein that is encoded by the FSCN1 gene (located on chromosome 7). It triggers membrane projections and stimulates cell motility in cancer cells. Fascin overexpression has been described in different types of human cancers in which its expression correlated with tumor growth, migration, invasion, and metastasis. Moreover, overexpression of fascin was found in oncovirus-infected cells, such as human papillomaviruses (HPVs) and Epstein-Barr virus (EBV), disrupting the cell–cell adhesion and enhancing cancer progression. Based on these findings, several studies reported fascin as a potential biomarker and a therapeutic target in various cancers. This review provides a brief overview of the FSCN1 role in various cancers with emphasis on gynecological malignancies. We also discuss fascin interactions with other genes and oncoviruses through which it might induce cancer development and progression.

Ovarian Cancer-Associated Mesothelial Cells: Transdifferentiation to Minions of Cancer and Orchestrate Developing Peritoneal Dissemination

Ovarian cancer has one of the poorest prognoses among carcinomas. Advanced ovarian cancer often develops ascites and peritoneal dissemination, which is one of the poor prognostic factors. From the perspective of the "seed and soil" hypothesis, the intra-abdominal environment is like the soil for the growth of ovarian cancer (OvCa) and mesothelial cells (MCs) line the top layer of this soil. In recent years, various functions of MCs have been reported, including supporting cancer in the OvCa microenvironment. We refer to OvCa-associated MCs (OCAMs) as MCs that are stimulated by OvCa and contribute to its progression. OCAMs promote OvCa cell adhesion to the peritoneum, invasion, and metastasis. Elucidation of these functions may lead to the identification of novel therapeutic targets that can delay OvCa progression, which is difficult to cure.

Microphthalmia-Associated Transcription Factor-Dependent Melanoma Cell Adhesion Molecule Activation Promotes Peritoneal Metastasis of Ovarian Cancer

Ovarian cancer (OvCa) is one of the leading causes of death due to its high metastasis rate to the peritoneum. Recurrent peritoneal tumors also develop despite the use of conventional platinum-based chemotherapies. Therefore, it is still important to explore the factors associated with peritoneal metastasis, as these predict the prognosis of patients with OvCa. In this study, we investigated the function of microphthalmia-associated transcription factor (MITF), which contributes to the development of melanoma, in epithelial ovarian cancer (OvCa). High MITF expression was significantly associated with a poor prognosis in OvCa. Notably, MITF contributed to the motility and invasion of OvCa cells, and specifically with their peri-mesothelial migration. In addition, MITF-positive cells expressed the melanoma cell adhesion molecule (MCAM/CD146), which was initially identified as a marker of melanoma progression and metastasis, and MCAM expression was regulated by MITF. MCAM was also identified as a significant prognostic factor for poor progression-free survival in patients with OvCa. Collectively, our results suggest that MITF is a novel therapeutic target that potentially promotes peritoneal metastasis of OvCa.

Cytoskeletal Remodeling in Cancer

Simple Summary

Cell migration is an essential process from embryogenesis to cell death. This is tightly regulated by numerous proteins that help in proper functioning of the cell. In diseases like cancer, this process is deregulated and helps in the dissemination of tumor cells from the primary site to secondary sites initiating the process of metastasis. For metastasis to be efficient, cytoskeletal components like actin, myosin, and intermediate filaments and their associated proteins should co-ordinate in an orderly fashion leading to the formation of many cellular protrusions-like lamellipodia and filopodia and invadopodia. Knowledge of this process is the key to control metastasis of cancer cells that leads to death in 90% of the patients. The focus of this review is giving an overall understanding of these process, concentrating on the changes in protein association and regulation and how the tumor cells use it to their advantage. Since the expression of cytoskeletal proteins can be directly related to the degree of malignancy, knowledge about these proteins will provide powerful tools to improve both cancer prognosis and treatment.

Abstract

Successful metastasis depends on cell invasion, migration, host immune escape, extravasation, and angiogenesis. The process of cell invasion and migration relies on the dynamic changes taking place in the cytoskeletal components; actin, tubulin and intermediate filaments. This is possible due to the plasticity of the cytoskeleton and coordinated action of all the three, is crucial for the process of metastasis from the primary site. Changes in cellular architecture by internal clues will affect the cell functions leading to the formation of different protrusions like lamellipodia, filopodia, and invadopodia that help in cell migration eventually leading to metastasis, which is life threatening than the formation of neoplasms. Understanding the signaling mechanisms involved, will give a better insight of the changes during metastasis, which will eventually help targeting proteins for treatment resulting in reduced mortality and longer survival.