Z47 - Synergistic Influence of Strain and Hyaluronic Acid on Ovarian and Breast Cancer

Friday, October 10, 2025

10:00 AM - 11:00 AM PDT

Location: Exhibit Hall F, G & H

Presenting Author(s)

Emerson Cutcliffe

Student
University of Alabama at Birmingham, United States

Co-Author(s)

MK

Maranda E. Kramer

Biomedical Engineer
Cerflux
Birmingham, Alabama, United States

Primary Investigator(s)

MK Sewell-Loftin

Assistant Professor
University of Alabama Birmingham, Alabama, United States

Introduction: : Ovarian and breast cancer share many similarities, such as hormonal regulation and intensified overlapping genetic mutation frequencies. These cancers often have an increased expression of the cell surface receptor CD44, which is associated with cancer progression through signaling pathways correlated with cancer proliferation and chemoresistance.
The tumor microenvironment (TME) of both ovarian and breast cancer contains hyaluronic acid (HA), which is a ligand of CD44 and is directly related to metastatic invasion. It has been shown that increased presence of HA is associated with a worse prognosis for ovarian cancer. Most of the HA present in the TME is produced by cancer-associated fibroblasts (CAFs), which are stromal cells present in the TME. Actomyosin contractility causes CAFs to have increased matrix remodeling. Increased contractility causes tensile strains that can affect tumor cells. Our lab has published studies on the mechanosignaling through the HA-CD44 axis and how this signaling alters ovarian cancer cell behaviors including growth and migration. These studies also demonstrated how Src, a non-receptor tyrosine kinase known to be important in mechanotransduction pathways, was regulated by CD44. This study investigated how a range of tensile strains alter ovarian and breast cancer expression of CD44 and Src with and without HA. Our hypothesis with these experiments was that increases in tensile strain elongation rates would increase CD44 and Src expression.

Materials and

Methods: : Cancer cells were cultured on Flex-Cell plates coated with HA prior to exposure to strain. Our cell line models included OVCAR-8, a high-grade serous ovarian cancer line and MDA-MB-231, a triple negative breast cancer cell line. Control samples were cultured on plates without HA. Cells were seeded at 500K cells/well and allowed to adhere for 24h. Samples were treated with uniaxial tensile strain stimulation at 0.3 Hz for 6h, 24h, or 48h using a Flex-Cell FX-6000T system. This process was repeated for 1, 9, or 12% elongation values. Control groups were not subjected to any mechanical stimulation (No Strain or 0%). Based on previous studies, the 9% elongation most closely aligns with CAF induced matrix deformations. Cells were then lysed for western blotting for CD44, Src, and -actin as a loading control. Samples were all run in triplicate on parallel membranes. Protein levels were first normalized to the loading control and then normalized to the average of the No HA, No Strain controls from the same blot.

Results, Conclusions, and Discussions:: For OVCAR-8 cells, CD44 levels are the highest at 9% elongation (Fig. 1a, 1b), while Src levels are the highest with 1% elongation, specifically with 6h of strain and the presence of HA (Fig. 1c, 1d). For MDA-MB-231 cells, CD44 levels are the highest with the presence of HA and no strain with lowest levels in groups with both the presence of HA and strain (Fig 2a). The highest levels of CD44 in OVCAR-8 cells is seen at 9% elongation with HA; as this condition most closely mimics the ovarian TME and CAF-induced strains, we believe this suggests how HA and strain may promote tumor progression. In these cells, Src levels were highest at 1% elongation with 6h, which shows that Src may be a more mechanically sensitive protein than CD44, as it took higher strain values to see similar increases in CD44. Src interacts with CD44 and the Receptor for Hyaluronan-Mediated Motility (RHAMM), which are both receptors for the HA ligand. These two interactions could help cause this increased sensitivity, as they are both being affected by strain and HA.
For MDA-MB-231 cells, the highest expression was found with the presence of HA and no strain, and the least expression was shown with both HA and 9% elongation strain for 6h. This data suggests that that HA and strain affect the expression of MDA-MB-231 differently than OVCAR-8.Our data indicates that HA may play a different role in influencing CD44 and Src expression in ovarian cancer compared to breast cancer. While CD44 and HA are known to cause worse prognoses for both cancer types, the specific mechanisms that drive this may be different. For future research, the other conditions tested for OVCAR-8 should also be tested for MDA-MB-231. There should also be research for shorter time periods to find when the changes in expression occur.

Acknowledgements and/or References (Optional): : The Authors would like to acknowledge funding for the project: T32EB023872-04 (M.E.K.) and ACS-RSG-24-1321527-01-MM (M.K.S.L.)