Abstract
In this study, we evaluated changes in focal adhesions (FAs) in two types of breast cancer cell (BCC) lines (differentiated MCF-7 and the triple-negative MDA-MB-231 cell line) exposed to simulated microgravity (s-μg) created by a random positioning machine (RPM) for 24 h. After exposure, the BCC changed their growth behavior and exhibited two phenotypes in RPM samples: one portion of the cells grew as a normal two-dimensional monolayer [adherent (AD) BCC], while the other portion formed three-dimensional (3D) multicellular spheroids (MCS). After 1 h and 30 min (MDA-MB-231) and 1 h 40 min (MCF-7), the MCS adhered completely to the slide flask bottom. After 2 h, MDA-MB-231 MCS cells started to migrate, and after 6 h, a large number of the cells had left the MCS and continued to grow in a scattered pattern, whereas MCF-7 cells were growing as a confluent monolayer after 6 h and 24 h. We investigated the genes associated with the cytoskeleton, the extracellular matrix and FAs. ACTB, TUBB, FN1, FAK1, and PXN gene expression patterns were not significantly changed in MDA-MB-231 cells, but we observed a down-regulation of LAMA3, ITGB1 mRNAs in AD cells and of ITGB1, TLN1 and VCL mRNAs in MDA-MB-231 MCS. RPM-exposed MCF-7 cells revealed a down-regulation in the gene expression of FAK1, PXN, TLN1, VCL and CDH1 in AD cells and PXN, TLN and CDH1 in MCS. An interaction analysis of the examined genes involved in 3D growth and adhesion indicated a central role of fibronectin, vinculin, and E-cadherin. Live cell imaging of eGFP-vinculin in MCF-7 cells confirmed these findings. β-catenin-transfected MCF-7 cells revealed a nuclear expression in 1g and RPM-AD cells. The target genes BCL9, MYC and JUN of the Wnt/β-catenin signaling pathway were differentially expressed in RPM-exposed MCF-7 cells. These findings suggest that vinculin and β-catenin are key mediators of BCC to form MCS during 24 h of RPM-exposure.
Highlights
Tumor diseases are a heavy burden for people around the world with high morbidity and mortality
The objective of this study was to (i) investigate the changes and growth of Breast cancer (BC) cells exposed to s-μg created by an random positioning machine (RPM), (ii) and to test, based on previous findings, the hypothesis that 24 h of exposure to s-μg cells induces the formation of multicellular spheroids (MCS) and alters the expression of genes related to the cytoskeleton, cell adhesion, and focal adhesions (FAs) in BC
MDA-MB-231 cells exhibited an epithelial-like morphology and appeared phenotypically as spindle-shaped cells under normal 1g static conditions (Figure 1D). Both breast cancer cell (BCC) types, the MCF-7 and MDA-MB-231 cells exposed to an RPM for 24 h showed two different phenotypes: adherent cells and multiple multicellular spheroids floating in the medium (Figures 1B,E)
Summary
Tumor diseases are a heavy burden for people around the world with high morbidity and mortality. According to data published by the WHO Global Cancer Observatory (GLOBOCAN) in 2020, tumor diseases were responsible for an estimated 10 million deaths in 2020 (Sung et al, 2021). Breast cancer (BC) is the most commonly diagnosed malignant tumor with an estimated 2.3 million new cases (11.7%) (Sung et al, 2021). Size, staging, and metastasis to sentinel lymph nodes, strategies like chemotherapy, radiation and anti-hormone therapy, targeted treatment against HER2, and anti-angiogenic therapy are often applied after surgery or in cases of advanced disease stage (Kristensen et al, 2014). It is estimated that about 684,996 deaths worldwide will occur from BC per year (Sung et al, 2021). Novel therapeutic strategies with the help of new technologies are required
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
