Fluid Shear Stress Induces Drug Resistance to Doxorubicin and Paclitaxel in the Breast Cancer Cell Line MCF7

Abstract

Circulating tumor cells (CTCs) are known to have cancer stem cell (CSC) properties and survive physiological conditions of fluid shear stress (FSS). However, current chemotherapy screening techniques do not adequately recapitulate this FSS environment and are not predictive of a drug response. In this study, MCF7 and MDA-MB-231 cells under FSS are used as an in vitro model of CTCs. The effects of doxorubicin (DOX) and paclitaxel on sheared cells using WST8 assay and stemness (CD44 + /CD24 − ) and apoptosis (Annexin V + /7-AAD + ) using flow cytometry are tested. Quantitative polymerase chain reaction is used to test gene expression. It is shown that suspension-cultured and FSS treated MCF7 cells increase in drug resistance, especially with DOX. There is a synergistic increase in the CD44 + /CD24 − CSC-like population and an increase in drug resistance-related gene expression in MCF7 cells co-treated with FSS and drugs. There is also a correlated increase in STAT3 and NANOG expression under FSS. To the best of the authors' knowledge, this is the first report to suggest that the increase in CSC-like cells from FSS contributes to drug resistance via the STAT3/NANOG pathway.This increase in CTC drug resistance also highlights the importance of implementing FSS, which is unavailable in current drug screening techniques.

The Role of Microenvironmental Cues and Mechanical Loading Milieus in Breast Cancer Cell Progression and Metastasis

“…Fluid shear Novak et al, 2019;Triantafillu et al, 2019 Fluid flow induced shear stress conditions may result in chemoresistance, e.g., to the drug paclitaxel and doxorubicin.…”

“…Moreover, cells with altered mechanical properties that survived shear in suspension were chemoresistant to the chemotherapy drug, fluorouracil, suggesting a connection between drug resistance and flow mechanotransduction. With more evidences that show flow shear may result in chemoresistance, e.g., to paclitaxel (Novak et al, 2019) and doxorubicin (Triantafillu et al, 2019), more holistic testing may be required to add mechanical signals such as flow to the current 2D monolayer high throughput screening test.…”

Cellular Mechanisms of Circulating Tumor Cells During Breast Cancer Metastasis

“…Currently, there are several strategies for applying FSS to cancer cells, several of which are summarized in Table 1 . Each of these models has been utilized to gain insight into various aspects of the mechanobiology of the CTCs, including their stemness [ 27 ], the generation of reactive oxygen species [ 28 ], drug resistance [ 29 , 30 ], promotion of the epithelial-mesenchymal transition (EMT) [ 31 ], fluctuation in hormone receptor expression [ 32 ], and facilitation of apoptosis [ 33 ], to name a few.…”

“…The syringe pump model is the simplest yet most robust CTC model. This device allows for the application of shear rates ranging from low (1 dyn/cm 2 ) to high (>60 dyn/cm 2 ), as per physiological standards [ 27 , 30 ]. The syringe pump is simple to use and stands on its own as a model for CTCs, but can also be incorporated into other models, such as perfusion and microfluidic devices for inducing flow.…”

“…Syringe pump Single-pass expulsion of cells from syringe through attached tubing into collection tube [27,30] Peristaltic pump…”