Alteration of Cytoskeleton Morphology and Gene Expression in Human Breast Cancer Cells under Simulated Microgravity

Cytoskeletal and Cytoskeleton-Associated Proteins: Key Regulators of Cancer Stem Cell Properties

Cancer stem cells (CSCs) are a subpopulation of cancer cells possessing stemness characteristics that are closely associated with tumor proliferation, recurrence and resistance to therapy. Recent studies have shown that different cytoskeletal components and remodeling processes have a profound impact on the behavior of CSCs. In this review, we outline the different cytoskeletal components regulating the properties of CSCs and discuss current and ongoing therapeutic strategies targeting the cytoskeleton. Given the many challenges currently faced in targeted cancer therapy, a deeper comprehension of the molecular events involved in the interaction of the cytoskeleton and CSCs will help us identify more effective therapeutic strategies to eliminate CSCs and ultimately improve patient survival.

ENAH regulates survival, self-renewal, and migration of patient-derived primary glioblastoma neurospheres.. [DOI: 10.21203/rs.3.rs-2042472/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Purpose: Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Despite standard treatment, the median survival of GBM patients is only 15 months. Enabled homolog (ENAH) is a member of the Ena/VASP protein family and regulates actin dynamics. ENAH has been implicated in a wide variety of cancers. But its role in GBM is less explored. We sought to understand the role of ENAH in GBM tumor biology. Methods: Expression of ENAH in GBM tumor specimens was assessed by immunohistochemistry (IHC). Patient-derived primary GBM neurosphere (GBMNS) models transfected with scrambled or target-specific ENAH siRNA were subjected to viability, apoptosis, neurosphere formation, western blot, transwell migration, and F-actin immunofluorescence assays. In vivo, we implanted mice with ENAH-intact and -depleted GBMNS intracranially and analyzed survival duration. Results: IHC analysis suggests that the expression of ENAH is higher in GBM tumor samples compared to low-grade gliomas and normal brain tissues. In vitro, ENAH knockdown reduced the viability of GBMNS by more than 50% by inducing apoptosis and significantly decreased the self-renewal ability. Also, we show that depletion of ENAH reduced the migration of GBMNS and demonstrated that ENAH is required for actin polymerization. Further, the expression of AXL-GAS6 was downregulated with the knockdown of ENAH. In vivo, transient depletion of ENAH significantly increased the survival of tumor-bearing mice. Conclusions: Our results suggest that ENAH is required for survival, self-renewal, and migration of GBMNS. Hence, ENAH can serve as a potential target for GBM therapy.

The Fight against Cancer by Microgravity: The Multicellular Spheroid as a Metastasis Model

Cancer is a disease exhibiting uncontrollable cell growth and spreading to other parts of the organism. It is a heavy, worldwide burden for mankind with high morbidity and mortality. Therefore, groundbreaking research and innovations are necessary. Research in space under microgravity (µg) conditions is a novel approach with the potential to fight cancer and develop future cancer therapies. Space travel is accompanied by adverse effects on our health, and there is a need to counteract these health problems. On the cellular level, studies have shown that real (r-) and simulated (s-) µg impact survival, apoptosis, proliferation, migration, and adhesion as well as the cytoskeleton, the extracellular matrix, focal adhesion, and growth factors in cancer cells. Moreover, the µg-environment induces in vitro 3D tumor models (multicellular spheroids and organoids) with a high potential for preclinical drug targeting, cancer drug development, and studying the processes of cancer progression and metastasis on a molecular level. This review focuses on the effects of r- and s-µg on different types of cells deriving from thyroid, breast, lung, skin, and prostate cancer, as well as tumors of the gastrointestinal tract. In addition, we summarize the current knowledge of the impact of µg on cancerous stem cells. The information demonstrates that µg has become an important new technology for increasing current knowledge of cancer biology.

Three-Dimensional Growth of Prostate Cancer Cells Exposed to Simulated Microgravity

Prostate cancer metastasis has an enormous impact on the mortality of cancer patients. Factors involved in cancer progression and metastasis are known to be key players in microgravity (µg)-driven three-dimensional (3D) cancer spheroid formation. We investigated PC-3 prostate cancer cells for 30 min, 2, 4 and 24 h on the random positioning machine (RPM), a device simulating µg on Earth. After a 24 h RPM-exposure, the cells could be divided into two groups: one grew as 3D multicellular spheroids (MCS), the other one as adherent monolayer (AD). No signs of apoptosis were visible. Among others, we focused on cytokines involved in the events of metastasis and MCS formation. After 24 h of exposure, in the MCS group we measured an increase in ACTB, MSN, COL1A1, LAMA3, FN1, TIMP1, FLT1, EGFR1, IL1A, IL6, CXCL8, and HIF1A mRNA expression, and in the AD group an elevation of LAMA3, COL1A1, FN1, MMP9, VEGFA, IL6, and CXCL8 mRNAs compared to samples subjected to 1 g conditions. Significant downregulations in AD cells were detected in the mRNA levels of TUBB, KRT8, IL1B, IL7, PIK3CB, AKT1 and MTOR after 24 h. The release of collagen-1α1 and fibronectin protein in the supernatant was decreased, whereas the secretion of IL-6 was elevated in 24 h RPM samples. The secretion of IL-1α, IL-1β, IL-7, IL-2, IL-8, IL-17, TNF-α, laminin, MMP-2, TIMP-1, osteopontin and EGF was not significantly altered after 24 h compared to 1 g conditions. The release of soluble factors was significantly reduced after 2 h (IL-1α, IL-2, IL-7, IL-8, IL-17, TNF-α, collagen-1α1, MMP-2, osteopontin) and elevated after 4 h (IL-1β, IL-2, IL-6, IL-7, IL-8, TNF-α, laminin) in RPM samples. Taken together, simulated µg induced 3D growth of PC-3 cancer cells combined with a differential expression of the cytokines IL-1α, IL-1β, IL-6 and IL-8, supporting their involvement in growth and progression of prostate cancer cells.

Cancer Studies under Space Conditions: Finding Answers Abroad

In this review article, we discuss the current state of knowledge in cancer research under real and simulated microgravity conditions and point out further research directions in this field. Outer space is an extremely hostile environment for human life, with radiation, microgravity, and vacuum posing significant hazards. Although the risk for cancer in astronauts is not clear, microgravity plays a thought-provoking role in the carcinogenesis of normal and cancer cells, causing such effects as multicellular spheroid formation, cytoskeleton rearrangement, alteration of gene expression and protein synthesis, and apoptosis. Furthermore, deleterious effects of radiation on cells seem to be accentuated under microgravity. Ground-based facilities have been used to study microgravity effects in addition to laborious experiments during parabolic flights or on space stations. Some potential 'gravisensors' have already been detected, and further identification of these mechanisms of mechanosensitivity could open up ways for therapeutic influence on cancer growth and apoptosis. These novel findings may help to find new effective cancer treatments and to provide health protection for humans on future long-term spaceflights and exploration of outer space.

Interleukin-18 and -10 may be associated with lymph node metastasis in breast cancer

Reports on the expression of interleukin (IL)-10 in breast cancer are rare. The present study investigated the correlation between IL-18 and −10 in breast cancer, and assessed their clinical significance. Breast cancer (n=104) and breast fibroadenoma (n=31) tissues that were surgically removed and pathologically confirmed at Jinan Central Hospital Affiliated to Shandong University (Jinan, China) between November 2016 and January 2019 were collected. The expression of IL-18 and −10 was observed via immunohistochemistry. Breast cancer tissues were positive for IL-18 expression, which was primarily located in the cell membrane and cytoplasm. A significant difference in IL-18 expression was observed between breast cancer and fibroadenoma tissues (75.0 vs. 19.4%; P<0.001). IL-10 was expressed in breast cancer tissues and primarily located in the cytoplasm. Breast cancer tissues showed a significantly higher level of IL-10 expression compared with breast fibroadenoma tissues (78.8 vs. 22.6%; P<0.001). The regions of positive IL-18 and −10 expression were consistent. Tissues with positive expression of IL-18 and/or −10 had a significantly higher rate of lymph node metastasis than those with negative expression (IL-18: 67.9 vs. 42.3%; P=0.035; and IL-10: 67.1 vs. 40.9%; P=0.047). In conclusion, IL-18 is highly expressed in breast cancer and correlates positively with IL-10. Both IL-18 and −10 may correlate positively with lymph node metastasis in breast cancer.

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.

Breast Cancer Cells in Microgravity: New Aspects for Cancer Research

Breast cancer is the leading cause of cancer death in females. The incidence has risen dramatically during recent decades. Dismissed as an "unsolved problem of the last century", breast cancer still represents a health burden with no effective solution identified so far. Microgravity (µg) research might be an unusual method to combat the disease, but cancer biologists decided to harness the power of µg as an exceptional method to increase efficacy and precision of future breast cancer therapies. Numerous studies have indicated that µg has a great impact on cancer cells; by influencing proliferation, survival, and migration, it shifts breast cancer cells toward a less aggressive phenotype. In addition, through the de novo generation of tumor spheroids, µg research provides a reliable in vitro 3D tumor model for preclinical cancer drug development and to study various processes of cancer progression. In summary, µg has become an important tool in understanding and influencing breast cancer biology.

Preparation and Characterization of a Novel Triple Composite Scaffold Containing Silk Fiborin, Chitosan, and Alginate for 3D Culture of Colonic Carcinoma Cells In Vitro

BACKGROUND Three-dimensional (3D) cell-culture scaffolds are ideal in vitro models to bridge the gap between two-dimensional cell culture in vitro and in vivo cancer models. Construction of 3D scaffolds using two kinds of biomaterials has been reported, but there are still many defects. To improve the performance of the scaffolds for 3D cell culture of colonic carcinoma (CC) cells in vitro, we attempted to construct triple composite scaffolds using silk fibroin (SF), chitosan (Cs), and alginate (Alg). MATERIAL AND METHODS We explored the suitability of triple composite scaffolds of SF/Cs/Alg at ratios of 1: 1: 0.5, 1: 1: 1, and 1: 1: 2 for 3D culture of CC cells, and used the dual composite scaffold of SF/Cs (1: 1) as a control group. We analyzed the physicochemical characteristics of these scaffolds and studied cell adhesion, cell proliferation, migration, colony-forming ability, microstructure and ultrastructure, and spheroid-forming capacity of the commercially available CC cell line HCT-116 on the prepared scaffolds. RESULTS Our results show that SF/Cs/Alg (1: 1: 1) scaffolds demonstrated the best profile, the highest uniform porosity and connectivity, and excellent hydroscopicity, and also exhibited appropriate and controlled swelling and degradation characteristics. The adhesion, proliferation, colony-forming, and wound-healing assays, green fluorescent protein-labeled HCT116 cell imaging, 4',6-diamidino-2-phenylindole and DY-554-phalloidin staining, scanning electron microscopy, and haematoxylin and eosin staining revealed that the triple composite scaffolds of SF/CS/Alg (1: 1: 1) supported cell adhesion, proliferation, migration, colony-forming ability, and spheroid formation far better than the dual composite scaffold of SF/CS (1: 1). CONCLUSIONS This study successfully demonstrated the potential of SF/Cs/Alg (1: 1: 1) scaffold as an alternative for the 3D in vitro culture of CC cells.