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Multicellular architecture of malignant breast epithelia influences mechanics.

Venugopalan G, Camarillo DB, Webster KD, Reber CD, Sethian JA, Weaver VM, Fletcher DA, El-Samad H, Rycroft CH - PLoS ONE (2014)

Bottom Line: Using creep compression tests on multicellular breast epithelial structures, we found that pre-malignant acini with no lumen (MCF10AT) were significantly stiffer than normal hollow acini (MCF10A) by 60%.This difference depended on structural changes in the pre-malignant acini, as neither single cells nor normal multicellular acini tested before lumen formation exhibited these differences.We also simulated a single contracting cell in different multicellular architectures and found that lumen filling led to a 20% increase in the "perceived stiffness" of a single contracting cell independent of any changes to matrix mechanics.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering and Biophysics Program, University of California, Berkeley, California, United States of America.

ABSTRACT
Cell-matrix and cell-cell mechanosensing are important in many cellular processes, particularly for epithelial cells. A crucial question, which remains unexplored, is how the mechanical microenvironment is altered as a result of changes to multicellular tissue structure during cancer progression. In this study, we investigated the influence of the multicellular tissue architecture on mechanical properties of the epithelial component of the mammary acinus. Using creep compression tests on multicellular breast epithelial structures, we found that pre-malignant acini with no lumen (MCF10AT) were significantly stiffer than normal hollow acini (MCF10A) by 60%. This difference depended on structural changes in the pre-malignant acini, as neither single cells nor normal multicellular acini tested before lumen formation exhibited these differences. To understand these differences, we simulated the deformation of the acini with different multicellular architectures and calculated their mechanical properties; our results suggest that lumen filling alone can explain the experimentally observed stiffness increase. We also simulated a single contracting cell in different multicellular architectures and found that lumen filling led to a 20% increase in the "perceived stiffness" of a single contracting cell independent of any changes to matrix mechanics. Our results suggest that lumen filling in carcinogenesis alters the mechanical microenvironment in multicellular epithelial structures, a phenotype that may cause downstream disruptions to mechanosensing.

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MCF10A and MCF10AT acini have different architectural and mechanical properties.Confocal immunofluorescence images of (A) non-malignant MCF10A (hollow lumen) and (B) pre-malignant MCF10AT (filled lumen) acini, taken after 15 days of growth. Scale bars 25 µm. (C) Creep compliance (mean ±95% CI) of hollow and filled breast epithelial acini. (N = 32 and 31 acini for A and T respectively) (D) Differences in mechanical response could be due to (1) different properties of single cells (2) changes in connectivity or (3) changes in multicellular architecture.
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pone-0101955-g002: MCF10A and MCF10AT acini have different architectural and mechanical properties.Confocal immunofluorescence images of (A) non-malignant MCF10A (hollow lumen) and (B) pre-malignant MCF10AT (filled lumen) acini, taken after 15 days of growth. Scale bars 25 µm. (C) Creep compliance (mean ±95% CI) of hollow and filled breast epithelial acini. (N = 32 and 31 acini for A and T respectively) (D) Differences in mechanical response could be due to (1) different properties of single cells (2) changes in connectivity or (3) changes in multicellular architecture.

Mentions: To measure the mechanical properties of healthy and pre-malignant acini, we used the MCF10A and MCF10AT model system. MCF10A cells are a human-derived breast epithelial cell line [19]. When embedded in laminin-rich ECM, MCF10A single cells grow into large structures with hollow lumina after a period of 2–3 weeks (Fig. 2A[20]). In contrast, c-Ha-ras transformed MCF10AT cells [21], [22] do not form lumina (Fig. 2B[2]). The MCF10A cell line has been previously used to demonstrate that breast epithelial cells sense ECM stiffness during acinar morphogenesis [3] and growth factor signaling [23].


Multicellular architecture of malignant breast epithelia influences mechanics.

Venugopalan G, Camarillo DB, Webster KD, Reber CD, Sethian JA, Weaver VM, Fletcher DA, El-Samad H, Rycroft CH - PLoS ONE (2014)

MCF10A and MCF10AT acini have different architectural and mechanical properties.Confocal immunofluorescence images of (A) non-malignant MCF10A (hollow lumen) and (B) pre-malignant MCF10AT (filled lumen) acini, taken after 15 days of growth. Scale bars 25 µm. (C) Creep compliance (mean ±95% CI) of hollow and filled breast epithelial acini. (N = 32 and 31 acini for A and T respectively) (D) Differences in mechanical response could be due to (1) different properties of single cells (2) changes in connectivity or (3) changes in multicellular architecture.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128597&req=5

pone-0101955-g002: MCF10A and MCF10AT acini have different architectural and mechanical properties.Confocal immunofluorescence images of (A) non-malignant MCF10A (hollow lumen) and (B) pre-malignant MCF10AT (filled lumen) acini, taken after 15 days of growth. Scale bars 25 µm. (C) Creep compliance (mean ±95% CI) of hollow and filled breast epithelial acini. (N = 32 and 31 acini for A and T respectively) (D) Differences in mechanical response could be due to (1) different properties of single cells (2) changes in connectivity or (3) changes in multicellular architecture.
Mentions: To measure the mechanical properties of healthy and pre-malignant acini, we used the MCF10A and MCF10AT model system. MCF10A cells are a human-derived breast epithelial cell line [19]. When embedded in laminin-rich ECM, MCF10A single cells grow into large structures with hollow lumina after a period of 2–3 weeks (Fig. 2A[20]). In contrast, c-Ha-ras transformed MCF10AT cells [21], [22] do not form lumina (Fig. 2B[2]). The MCF10A cell line has been previously used to demonstrate that breast epithelial cells sense ECM stiffness during acinar morphogenesis [3] and growth factor signaling [23].

Bottom Line: Using creep compression tests on multicellular breast epithelial structures, we found that pre-malignant acini with no lumen (MCF10AT) were significantly stiffer than normal hollow acini (MCF10A) by 60%.This difference depended on structural changes in the pre-malignant acini, as neither single cells nor normal multicellular acini tested before lumen formation exhibited these differences.We also simulated a single contracting cell in different multicellular architectures and found that lumen filling led to a 20% increase in the "perceived stiffness" of a single contracting cell independent of any changes to matrix mechanics.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering and Biophysics Program, University of California, Berkeley, California, United States of America.

ABSTRACT
Cell-matrix and cell-cell mechanosensing are important in many cellular processes, particularly for epithelial cells. A crucial question, which remains unexplored, is how the mechanical microenvironment is altered as a result of changes to multicellular tissue structure during cancer progression. In this study, we investigated the influence of the multicellular tissue architecture on mechanical properties of the epithelial component of the mammary acinus. Using creep compression tests on multicellular breast epithelial structures, we found that pre-malignant acini with no lumen (MCF10AT) were significantly stiffer than normal hollow acini (MCF10A) by 60%. This difference depended on structural changes in the pre-malignant acini, as neither single cells nor normal multicellular acini tested before lumen formation exhibited these differences. To understand these differences, we simulated the deformation of the acini with different multicellular architectures and calculated their mechanical properties; our results suggest that lumen filling alone can explain the experimentally observed stiffness increase. We also simulated a single contracting cell in different multicellular architectures and found that lumen filling led to a 20% increase in the "perceived stiffness" of a single contracting cell independent of any changes to matrix mechanics. Our results suggest that lumen filling in carcinogenesis alters the mechanical microenvironment in multicellular epithelial structures, a phenotype that may cause downstream disruptions to mechanosensing.

Show MeSH
Related in: MedlinePlus