Skip to main content
2023 BMES Annual Meeting Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
Back

    Cellular and Molecular Bioengineering

    (H-319) Investigating the effects of fluid shear stress on the progression of post-partum breast cancer

    Saturday, October 14, 2023
    9:30 AM – 10:30 AM PDT
    Location: Exhibit Hall - Row H - Poster # 319
    Introduction:


    In 2020, there were 2.26 million new cases of breast cancer globally. Postpartum breast cancer (PPBC), which occurs within 5 years after childbirth, is a particularly harmful subsection of breast cancer affecting new mothers (< 45 years old) with young children. PPBC is not well understood and has an increased risk of death and distant metastasis compared to women diagnosed prior to or during pregnancy. Due to the lack of screening processes or effective diagnostics, PPBC patients often present with developed, stage IV diagnoses that have already metastasized, making subsequent treatments difficult. This all makes PPBC a particularly significant illness requiring investigation.


    During pregnancy, cell density increases exponentially, with the acceleration of blood flow promoting milk duct development. The breasts undergo different mammary gland development stages through the postpartum period: lactation, cessation, and involution. During involution, milk-producing epithelial cells are killed and removed, returning the mammary gland to its pre-lactation state. This involves activation of multiple processes including inflammation, wound healing, and lymphangiogenesis, that are linked to mechanical forces induced by fluid shear stress on the cells. This stage is hypothesized to contribute to the progression of breast cancer. Furthermore, fluid flow over cells, causing fluid shear stress, is linked to upregulation of genes related to breast cancer progression, particularly relevant for PPBC, which is highly metastatic.


    This project’s goal is to investigate the effect of shear stress throughout the mammary gland development stages on breast cancer cells, expanding on a bioreactor-based model currently in development in the Rinker Lab.





    Materials and Methods:


    The role of fluid shear stress in the progression of cancer remains relatively unexplored. Using a bioreactor-based model currently in development in the Rinker Lab, breast cancer cells will run under flow in a parallel plate flow chamber, exposing the cells to a set amount of fluid shear stress. Different levels of shear stress across specific time points have been established previously to mimic the postpartum period in vitro using a continuous bioreactor, which we employ. Protein and RNA is then extracted, quantified, and qualified using a nanodrop, among other methods, and will be analyzed. From the quality control side, the parallel plate flow chambers used have been optimized and the quality of samples produced have been evaluated by the quantity and quality of RNA, so we manage cell viability while ensuring that we administer the correct level of shear stress to achieve our aims for the study.


    Currently, we are working to generate samples for analysis providing insight into the genetic effects of shear stress on breast cancer cells. These results will be combined with previously generated proteomic analysis of similar cells and analyzed using machine learning, data mining, and analysis to identify relevant targets. The results will also be analyzed with datasets developed from cells run under fluid flow in the presence of lactogenic hormones from a bioreactor cell model engineered and validated by the Rinker Lab. We will compare identified biomarkers to targets established in literature as well as publicly available datasets.




    Results, Conclusions, and Discussions:


    Validation of our bioreactor used to generate the samples was a significant aspect of the study so far. While some initial samples did fail, identified using our quality control methods, this led us to shifting the extraction method of the RNA following the flow run and modifying other sections of our protocols and methods so to achieve the necessary amount of RNA required to conduct genomic sequencing. Currently with our validated and optimized system, we are accumulating samples at the different time points throughout the postpartum mammary gland development stages to be able to analyze and compare them. These results will then be contrasted with previously generated data and publicly available data to further extract potentially clinically relevant information from our results. Newfound targets will contribute to further investigation and validation of these and previously identified targets using western blotting.


    Other research in the lab investigating fluid shear stress with flow in the presence of lactogenic hormones suggests that breast cancer cells are responsive to shear stress stimulation throughout the mammary gland development time points. Previous analysis of the generated proteomic data identified several gene ontology pathways associated with metastasis as well as pathways that are in common with involution, suggesting that fluid shear stress is in fact a relevant stimulus in the progression of PPBC. Several targets were identified from samples exposed to fluid shear stress and publicly available involution datasets that will be analyzed and further validated with the genomic and further proteomic samples. Future Next Generation Sequencing in particular will be able to not only validate the markers and pathways already found, but also explore new targets that will then be further validated with methods such as western blotting.


    With the goal of understanding what mechanically promotes PPBC progression and identify associated biomarkers, particularly during involution, future work will use the validated model to test relevant targets identified from analysis of generated datasets. Long-term, this may help in the development of effective PPBC diagnostic technologies that can help improve health outcomes of this vulnerable patient population.