Cellular Structure AnalysisMB231 Cell Line

Hypothesis

Effect of Substrate RigidityOn Breast Cancer Cells

Elizabeth L. Smith, RET Fellow 2011West Aurora High School

RET Mentor: Dr. Michael Cho, PhD NSF- RET Program

MotivationAbstract

Conclusion

Material and Methods

Results

NSF Grant CBET-EEC-0743068

Prof. A. Linninger, RET Program Director

Dr. Michael Cho, Research Advisor

Brandon Lutz, Research Mentor

University of Illinois- Chicago

Acknowledgements

References1. Breastcancer.org (April 19th, 2011). U.S. Breast Cancer Statistics. Breastcancer.org. Retrieved July 26, 2011,

from http://www.breastcancer.org/symptoms/understand_bc/statistics.jsp2. Curtis, A., & Wilkinson, C. (January 01, 1997). Topographical control of cells. Biomaterials, 18, 24, 1573.3. Guo, W. H., Frey, M. T., Burnham, N. A., & Wang, Y. L. (January 01, 2006). Substrate rigidity regulates the

formation and maintenance of tissues. Biophysical Journal,90, 6, 2213-20.4. Rapier, R., Huq, J., Vishnubhotla, R., Bulic, M., Perrault, C. M., Metlushko, V., Cho, M., ... Glover, S. C.

(January 01, 2010). The extracellular matrix microtopography drives critical changes in cellular motility and Rho A activity in colon cancer cells. Cancer Cell International, 10.

5. Tzvetkova-Chevolleau, T., Stephanou, A., Fuard, D., Ohayon, J., Schiavone, P., & Tracqui, P. (January 01, 2008). The motility of normal and cancer cells in response to the combined influence of the substrate rigidity and anisotropic microstructure. Biomaterials,29, 10, 1541-51.

Breast cancer cells will change structure in response to varying substrate stiffness

Day 1 Day 7

*

Average Number of Cells per ViewMB231 Cell Line

Rigid Substrate10:1 PDMS

Soft Substrate30:1 PDMS

StatisticalSignificance*

Two Substrates

Polymer : Cross-linking

RatioRigidity

Rigid PDMS 10:1 2.2 MPa

Soft PDMS 30:1 0.3 MPa

Two Cell Lines

Tissue Mobility

MB231 Breast Invasive

MCF7 Breast Less invasive

Analysis 2 samples - Each Cell line on Each SubstrateCollected - Day 1, Day 3, Day 7

Florescent Microscopy

Dye Target Indicates Color

Actin Cytoskelton Red

VinculinFocal Adhesions

Green

DNA Nucleus Blue

MetamorphSoftware

- Images psuedocolored and overlaid

ImageJSoftware

-Cell count determined using nuclei-RGB intensities quantified for each image then normalized by cell count

Microsoft Excel

-Statistical Analysis & Graph Making

Hypothesis

1 in 8 women in the U.S. will be diagnosed

with breast cancer in their lifetime

Breast cancer is the

second deadliest cancer in women1

Cancer cells interact with the environment around them in a bidirectional manner. While metastatic cells modify the environment and navigate through it, the environment exerts significant influence over the cell’s shape, structure, and behavior.2,3,4,5

This study was designed to examine how two breast cancer lines, MB231 and MCF7, respond to PDMS (polydimethylsiloxane) substrates that differ in the rigidity by an order of magnitude.

Less invasive MCF7 cells adhere poorly to PDMS independent of the rigidity, suggesting lack of focal adhesion. Highly invasive MB231 cells showed greater proliferation on the soft substrate, as well as significantly greater actin fibers and focal adhesions. Invasive MB231 cells alter their structure based on substrate rigidity.

Understanding the rigidity-dependent cancer cell behavior may lead to development of better cancer diagnoses, therapies, and potentially cures.

MB231 cell growing on 10:1 PDMS at 40x magnification

100 um