title: Non-Muscle Myosin II Isoforms Have Different Functions in Matrix Rearrangement by MDA-MB-231 Cells.
abstract: The role of a stiffening extra-cellular matrix (ECM) in cancer progression is documented but poorly understood. Here we use a conditioning protocol to test the role of nonmuscle myosin II isoforms in cell mediated ECM arrangement using collagen constructs seeded with breast cancer cells expressing shRNA targeted to either the IIA or IIB heavy chain isoform. While there are several methods available to measure changes in the biophysical characteristics of the ECM, we wanted to use a method which allows for the measurement of global stiffness changes as well as a dynamic response from the sample over time. The conditioning protocol used allows the direct measurement of ECM stiffness. Using various treatments, it is possible to determine the contribution of various construct and cellular components to the overall construct stiffness. Using this assay, we show that both the IIA and IIB isoforms are necessary for efficient matrix remodeling by MDA-MB-231 breast cancer cells, as loss of either isoform changes the stiffness of the collagen constructs as measured using our conditioning protocol. Constructs containing only collagen had an elastic modulus of 0.40 Pascals (Pa), parental MDA-MB-231 constructs had an elastic modulus of 9.22 Pa, while IIA and IIB KD constructs had moduli of 3.42 and 7.20 Pa, respectively. We also calculated the cell and matrix contributions to the overall sample elastic modulus. Loss of either myosin isoform resulted in decreased cell stiffness, as well as a decrease in the stiffness of the cell-altered collagen matrices. While the total construct modulus for the IIB KD cells was lower than that of the parental cells, the IIB KD cell-altered matrices actually had a higher elastic modulus than the parental cell-altered matrices (4.73 versus 4.38 Pa). These results indicate that the IIA and IIB heavy chains play distinct and non-redundant roles in matrix remodeling.
authors.affiliation: Mary Babb Randolph Cancer Center, West Virginia University, Robert C. Byrd Health Sciences Center, Morgantown, West Virginia, United States of America.
authors.forename: Bridget
authors.initials: B
authors.lastname: Hindman
authors.affiliation: Center for Cardiovascular and Respiratory Diseases, West Virginia University, Robert C. Byrd Health Sciences Center, Morgantown, West Virginia, United States of America.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Goeckeler
authors.affiliation: Mechanical and Aerospace Engineering, Statler College of Engineering and Mineral Resources, West Virginia University, Morgantown, West Virginia, United States of America.
authors.forename: Kostas
authors.initials: K
authors.lastname: Sierros
authors.affiliation: Mary Babb Randolph Cancer Center, West Virginia University, Robert C. Byrd Health Sciences Center, Morgantown, West Virginia, United States of America; Center for Cardiovascular and Respiratory Diseases, West Virginia University, Robert C. Byrd Health Sciences Center, Morgantown, West Virginia, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Wysolmerski
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D003094:Collagen / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D055119:Elastic Modulus; D005109:Extracellular Matrix / Q000378:metabolism*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D024507:Nonmuscle Myosin Type IIA / Q000235:genetics*; D024501:Nonmuscle Myosin Type IIB / Q000235:genetics*; D034741:RNA, Small Interfering / Q000378:metabolism; D013314:Stress, Mechanical
chemical_list: D034741:RNA, Small Interfering; D003094:Collagen; D004247:DNA; D024507:Nonmuscle Myosin Type IIA; D024501:Nonmuscle Myosin Type IIB