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Schmidt M, Boulanger-Espeut C, Liou G, Ma N, Torres S, Cersosimo S, Bogler O, Zahir N. Evaluation of the National Cancer Institute (NCI) Pathway to Independence Award (K99/R00) Program. J Cancer Educ 2024:10.1007/s13187-024-02420-1. [PMID: 38499846 DOI: 10.1007/s13187-024-02420-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/29/2024] [Indexed: 03/20/2024]
Abstract
The National Cancer Institute (NCI) K99/R00 award is intended to help postdoctoral scholars transition in a timely manner to research independence and to foster their development of an impactful cancer research program that is competitive for subsequent independent funding. Here we analyzed factors that impact peer review outcomes and evaluated whether NCI K99/R00 awardees have achieved the goals of the K99/R00 funding mechanism. Our analysis of the K99/R00 review criterion scores demonstrates that while all review criterion scores are positively correlated with the overall impact score, the Research Plan criterion is the strongest predictor of the overall impact score and funding outcomes. In addition, our analysis shows the NCI K99/R00 award facilitated the successful transition of postdoctoral scholars to research independence and enhanced the likelihood of K99/R00 awardees to secure subsequent R01-equivalent NIH grant support although not in an accelerated fashion as originally intended. An NCI K99/R00 award was not determined to be a prerequisite to obtain a faculty position, but for some awardees, it was an asset in that transition. Our results suggest that the NCI K99/R00 award is an important component for training and retention of the next generation of independent cancer researchers and to increasing the percentage of women and promoting the diversity of the cancer research workforce.
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Affiliation(s)
- Michael Schmidt
- National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
| | | | - Grace Liou
- National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
| | - Nan Ma
- Digital Science, Inc, Cambridge, MA, 02139, USA
| | - Sasha Torres
- National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
| | - Susan Cersosimo
- National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
| | - Oliver Bogler
- National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
| | - Nastaran Zahir
- National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA.
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Abstract
Owing to clinical success of immune-checkpoint blockade, immunotherapy is becoming a cornerstone of modern oncology, and immuno-oncology is at the forefront of basic cancer research. This commentary outlines future opportunities for immuno-oncology modeling.
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Affiliation(s)
- Claire E McCarthy
- Division of Cancer Biology, National Cancer Institute, Rockville, MD, USA
| | - Nastaran Zahir
- Division of Cancer Biology, National Cancer Institute, Rockville, MD, USA
| | - Mariam Eljanne
- Division of Cancer Biology, National Cancer Institute, Rockville, MD, USA
| | - Elad Sharon
- Cancer Therapy Evaluation Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Rockville, MD, USA
| | - Emile E Voest
- Department of Molecular Oncology and Immunology, Netherlands Cancer Institute, Amsterdam, the Netherlands; Oncode Institute, Amsterdam, the Netherlands.
| | - Karolina Palucka
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA.
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3
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Drain AP, Zahir N, Northey JJ, Zhang H, Huang PJ, Maller O, Lakins JN, Yu X, Leight JL, Alston-Mills BP, Hwang ES, Chen YY, Park CC, Weaver VM. Matrix compliance permits NF-κB activation to drive therapy resistance in breast cancer. J Exp Med 2021; 218:e20191360. [PMID: 33822843 PMCID: PMC8025243 DOI: 10.1084/jem.20191360] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 12/07/2020] [Accepted: 02/12/2021] [Indexed: 01/10/2023] Open
Abstract
Triple-negative breast cancers (TNBCs) are associated with poor survival mediated by treatment resistance. TNBCs are fibrotic, yet little is known regarding how the extracellular matrix (ECM) evolves following therapy and whether it impacts treatment response. Analysis revealed that while primary untreated TNBCs are surrounded by a rigid stromal microenvironment, chemotherapy-resistant residual tumors inhabit a softer niche. TNBC organoid cultures and xenograft studies showed that organoids interacting with soft ECM exhibit striking resistance to chemotherapy, ionizing radiation, and death receptor ligand TRAIL. A stiff ECM enhanced proapoptotic JNK activity to sensitize cells to treatment, whereas a soft ECM promoted treatment resistance by elevating NF-κB activity and compromising JNK activity. Treatment-resistant residual TNBCs residing within soft stroma had elevated activated NF-κB levels, and disengaging NF-κB activity sensitized tumors in a soft matrix to therapy. Thus, the biophysical properties of the ECM modify treatment response, and agents that modulate stiffness-dependent NF-κB or JNK activity could enhance therapeutic efficacy in patients with TNBC.
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Affiliation(s)
- Allison P. Drain
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA
- University of California, Berkeley–University of California, San Francisco Graduate Program in Bioengineering, University of California, San Francisco, San Francisco, CA
| | - Nastaran Zahir
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA
| | - Jason J. Northey
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA
| | - Hui Zhang
- Department of Radiation Oncology, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA
| | - Po-Jui Huang
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA
| | - Ori Maller
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA
| | - Johnathon N. Lakins
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA
| | - Xinmiao Yu
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA
| | - Jennifer L. Leight
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA
| | - Brenda P. Alston-Mills
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA
| | - E. Shelley Hwang
- Department of Surgery, Duke University Medical Center, Durham, NC
| | - Yunn-Yi Chen
- Department of Pathology, University of California, San Francisco, San Francisco, CA
| | - Catherine C. Park
- Department of Radiation Oncology, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA
- University of California, San Francisco Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA
| | - Valerie M. Weaver
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA
- University of California, San Francisco Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA
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4
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Zahir N, Couch J. The NCI Cancer Tissue Engineering Collaborative Research Program is a highly interdisciplinary and focused community. iScience 2021; 24:102441. [PMID: 34007960 PMCID: PMC8111673 DOI: 10.1016/j.isci.2021.102441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Nastaran Zahir
- Division of Cancer Biology, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Jennifer Couch
- Division of Cancer Biology, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
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Walker SA, Pham A, Nizzero S, Kim M, Riter B, Bletz J, Judge S, Phillips B, Noble D, Murray D, Wetzel E, Samson S, McMahon M, Flink C, Couch J, Tomlin C, Swanson K, Anderson ARA, Odde D, Shen H, Hughes S, Zahir N, Enderling H, Wolfram J. Education and Outreach in Physical Sciences in Oncology. Trends Cancer 2021; 7:3-9. [PMID: 33168416 PMCID: PMC7895467 DOI: 10.1016/j.trecan.2020.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 01/22/2023]
Abstract
Physical sciences are often overlooked in the field of cancer research. The Physical Sciences in Oncology Initiative was launched to integrate physics, mathematics, chemistry, and engineering with cancer research and clinical oncology through education, outreach, and collaboration. Here, we provide a framework for education and outreach in emerging transdisciplinary fields.
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Affiliation(s)
- Sierra A Walker
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Jacksonville, FL, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Jacksonville, FL, USA; Department of Transplantation, Mayo Clinic, Jacksonville, FL, USA
| | - Anthony Pham
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Jacksonville, FL, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Jacksonville, FL, USA; Department of Transplantation, Mayo Clinic, Jacksonville, FL, USA
| | - Sara Nizzero
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, TX, USA
| | - Mingee Kim
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, TX, USA
| | - Bob Riter
- Physical Sciences Oncology Center, Cornell University, Ithaca, NY, USA
| | | | - Sheila Judge
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - Benette Phillips
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Dorottya Noble
- Cancer Systems Biology Center, Yale University, New Haven, CT, USA; Program in Physics, Engineering and Biology, Yale University, New Haven, CT, USA
| | - Diana Murray
- Department of Systems Biology, Columbia University Medical Center, New York, NY, USA
| | - Erin Wetzel
- Division of Cancer Biology, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Susan Samson
- Breast Oncology Program, Breast Science Advocacy Core University of California, San Francisco, CA, 94115, USA; Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, CA, 94115, USA
| | - Mariah McMahon
- Physical Sciences Oncology Center, Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Carl Flink
- Physical Sciences Oncology Center, Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Jennifer Couch
- Division of Cancer Biology, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Claire Tomlin
- M2CH Center for Cancer Systems Biology, University of California, Berkeley, CA, USA
| | - Kristin Swanson
- Mathematical Neuro Oncology Lab, Mayo Clinic, Phoenix, AZ, USA
| | - Alexander R A Anderson
- Department of Integrated Mathematical Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA
| | - David Odde
- Physical Sciences Oncology Center, Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Haifa Shen
- Center for Immunotherapeutic Transport Oncophysics, Houston Methodist Research Institute, Houston, TX, USA
| | - Shannon Hughes
- Division of Cancer Biology, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Nastaran Zahir
- Division of Cancer Biology, National Cancer Institute, National Institutes of Health, Rockville, MD, USA.
| | - Heiko Enderling
- Department of Integrated Mathematical Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA.
| | - Joy Wolfram
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Jacksonville, FL, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Jacksonville, FL, USA; Department of Transplantation, Mayo Clinic, Jacksonville, FL, USA; Center for Immunotherapeutic Transport Oncophysics, Houston Methodist Research Institute, Houston, TX, USA.
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Samson S, Zahir N, Judge SM, Cornew S, Riter B, Francoeur J, Meyn A, Cynkin L, Northey JJ, Weaver VM, Baas C. Abstract 4767: Regional strategies for expanding the evolving continuum of Physical Sciences-Oncology Network (PS-ON) research advocacy experiences. Cancer Res 2018. [DOI: 10.1158/1538-7445.am2018-4767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: The National Cancer Institute (NCI) Physical Sciences-Oncology Network (PS-ON), initiated in 2009, is an interdisciplinary hub currently consisting of eighteen regions across the nation to support the emergence of new scientific frontiers, principles, and opportunities within physical sciences and oncology. Based on the belief that the increasing momentum for cross-disciplinary connectivity between biologists, physicists, mathematicians, chemists, biomedical engineers, and oncologists would be enriched and enhanced by vigorous and diverse public and/or advocacy support, the PS-ON leadership, at program inception, incorporated the advocate voice in setting a national research agenda.
Methods: While the regional advocacy programs operate independently and utilize multilevel, multimethod strategies to expand the evolving umbrella of research advocacy experiences, they are connected through an administrative structure that communicates NCI program priorities to enhance capacity in the approaches utilized across the eighteen PS-ON regions.
Impact: As integral team members, advocates bring real-time diverse patient experiences, diverse professional expertise, and concerns into pioneering, innovative research practices. PS-ON regional engagement/communication strategies include: 1) integrating advocate perspectives to shape basic science research agendas, 2) developing conceptual models/roadmaps to holistic engagement focusing on organizational foundations and best practice strategies, 3) applying guiding frameworks and toolkits for setting the terms of principled engagement/shared governance/bidirectional collaboration, 4) implementing education, outreach, and professional development programs for early-stage investigators, students, and patient communities, and 5) translating, communicating and disseminating laboratory innovations into society.
Discussion: To better understand and fully address the complexities of intersecting physical sciences and oncology advocacy engagement, we explore the unique culture and guidelines set by selected participating institutions. Meeting key challenges regarding programmatic scope and policy impact requires a shift to a new, rapidly evolving paradigm. In parallel to incentives and policy measures created through federal and professional organizations, we offer recommendations for strengthening regional programs and encouraging equitable partnerships for advocates at earlier stages of research to help propel convergent science innovation.
Citation Format: Susan Samson, Nastaran Zahir, Sheila M. Judge, Stuart Cornew, Bob Riter, Jeri Francoeur, Anne Meyn, Laurie Cynkin, Jason J. Northey, Valerie M. Weaver, Carole Baas. Regional strategies for expanding the evolving continuum of Physical Sciences-Oncology Network (PS-ON) research advocacy experiences [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4767.
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Affiliation(s)
- Susan Samson
- 1University of California Comprehensive Cancer Center, Breast and Physical Sciences and Oncology Programs/Breast Science Advocacy Core, San Francisco, CA
| | - Nastaran Zahir
- 2Division of Cancer Biology, National Cancer Institute, National Institutes of Health, Rockville, MD
| | - Sheila M. Judge
- 3Chemistry of Life Processes Institute, Northwestern University, Evanston, IL
| | - Stuart Cornew
- 4Chicago Region Physical Sciences-Oncology Center, Chicago, IL
| | - Bob Riter
- 5Cornell University Physical Sciences-Oncology Center, Ithaca, NY
| | - Jeri Francoeur
- 6Moffitt Physical Sciences-Oncology Center, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL
| | - Anne Meyn
- 7Physical Sciences-Oncology Center (PS-OC), Houston Methodist Research Institute, Houston, TX
| | - Laurie Cynkin
- 8Office of Advocacy Relations, National Cancer Institute, National Institutes of Health, Rockville, MD
| | - Jason J. Northey
- 9Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, CA
| | - Valerie M. Weaver
- 9Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, CA
| | - Carole Baas
- 10Physical Sciences-Oncology Network and Office of Advocacy Relations, National Cancer Institute, National Institutes of Health, Rockville, MD
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Zahir N, Heyman MB, Wojcicki JM. No association between childcare and obesity at age 4 in low-income Latino children. Pediatr Obes 2013; 8:e24-8. [PMID: 23239621 PMCID: PMC4618503 DOI: 10.1111/j.2047-6310.2012.00125.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 09/14/2012] [Accepted: 10/24/2012] [Indexed: 11/28/2022]
Abstract
BACKGROUND Previous studies have found an association between early entry to childcare and risk for overweight and obesity at 3 years of age. These studies, however, have been conducted primarily with higher income White populations or have found increased risk in the children of educated mothers. OBJECTIVE To assess the relationship between timing of entry to childcare and duration of childcare and pediatric overweight and obesity in a high risk population. METHODS Using data from a longitudinal cohort of low-income Latino children in San Francisco, we evaluated the association between time of entry to childcare, hours in childcare, and risk for overweight and obesity at age 4. Similarly, we evaluated the relationship between these same childcare parameters and body mass index Z score and risk of having a waist circumference (WC) percentile ≥90th at 4 years of age. RESULTS In contrast with previous studies, we found no association between being in childcare at 4 years of age or number of hours per week in childcare and risk for childhood overweight, obesity or WC ≥90th percentile at age 4. Additionally, we found no association between age of entry to childcare (≤6 months or ≤12 months of age) with risk for overweight or obesity at age 4. Future studies need to further evaluate the differential impact of childcare on early childhood obesity in relation to race/ethnicity and lower socioeconomic status. CONCLUSION Low-income children may not be at increased risk for obesity in relation to early childcare exposure.
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Affiliation(s)
- N. Zahir
- Department of Pediatric Gastroenterology, Hepatology and Nutrition; UCSF; San Francisco; CA; USA
| | - M. B. Heyman
- Department of Pediatric Gastroenterology, Hepatology and Nutrition; UCSF; San Francisco; CA; USA
| | - J. M. Wojcicki
- Department of Pediatric Gastroenterology, Hepatology and Nutrition; UCSF; San Francisco; CA; USA
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Paszek MJ, Zahir N, Johnson KR, Lakins JN, Rozenberg GI, Gefen A, Reinhart-King CA, Margulies SS, Dembo M, Boettiger D, Hammer DA, Weaver VM. Tensional homeostasis and the malignant phenotype. Cancer Cell 2005; 8:241-54. [PMID: 16169468 DOI: 10.1016/j.ccr.2005.08.010] [Citation(s) in RCA: 2739] [Impact Index Per Article: 144.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 08/15/2005] [Accepted: 08/24/2005] [Indexed: 12/12/2022]
Abstract
Tumors are stiffer than normal tissue, and tumors have altered integrins. Because integrins are mechanotransducers that regulate cell fate, we asked whether tissue stiffness could promote malignant behavior by modulating integrins. We found that tumors are rigid because they have a stiff stroma and elevated Rho-dependent cytoskeletal tension that drives focal adhesions, disrupts adherens junctions, perturbs tissue polarity, enhances growth, and hinders lumen formation. Matrix stiffness perturbs epithelial morphogenesis by clustering integrins to enhance ERK activation and increase ROCK-generated contractility and focal adhesions. Contractile, EGF-transformed epithelia with elevated ERK and Rho activity could be phenotypically reverted to tissues lacking focal adhesions if Rho-generated contractility or ERK activity was decreased. Thus, ERK and Rho constitute part of an integrated mechanoregulatory circuit linking matrix stiffness to cytoskeletal tension through integrins to regulate tissue phenotype.
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Affiliation(s)
- Matthew J Paszek
- Department of Bioengineering, University of Pennsylvania, Philadelphia, 19104, USA
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9
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Yeung T, Georges PC, Flanagan LA, Marg B, Ortiz M, Funaki M, Zahir N, Ming W, Weaver V, Janmey PA. Effects of substrate stiffness on cell morphology, cytoskeletal structure, and adhesion. Cell Motil Cytoskeleton 2005. [PMID: 15573414 DOI: 10.1002/cm.v60:1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
Abstract
The morphology and cytoskeletal structure of fibroblasts, endothelial cells, and neutrophils are documented for cells cultured on surfaces with stiffness ranging from 2 to 55,000 Pa that have been laminated with fibronectin or collagen as adhesive ligand. When grown in sparse culture with no cell-cell contacts, fibroblasts and endothelial cells show an abrupt change in spread area that occurs at a stiffness range around 3,000 Pa. No actin stress fibers are seen in fibroblasts on soft surfaces, and the appearance of stress fibers is abrupt and complete at a stiffness range coincident with that at which they spread. Upregulation of alpha5 integrin also occurs in the same stiffness range, but exogenous expression of alpha5 integrin is not sufficient to cause cell spreading on soft surfaces. Neutrophils, in contrast, show no dependence of either resting shape or ability to spread after activation when cultured on surfaces as soft as 2 Pa compared to glass. The shape and cytoskeletal differences evident in single cells on soft compared to hard substrates are eliminated when fibroblasts or endothelial cells make cell-cell contact. These results support the hypothesis that mechanical factors impact different cell types in fundamentally different ways, and can trigger specific changes similar to those stimulated by soluble ligands.
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Affiliation(s)
- Tony Yeung
- Institute for Medicine and Engineering, University of Pennsylvania, PA 19104, USA
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Abstract
Tissue development, homeostasis and tumor pathogenesis all depend upon a complex dialogue between multiple cell types operating within a dynamic three-dimensional (3D) tissue extracellular matrix microenvironment. A major issue is whether the spatial organization of a cell within this 3D tissue microenvironment could modulate cell responsiveness to regulate cell fate decisions such as survival, and if so how. Classic developmental model systems and transgenic animals are instructive but pose special challenges for investigators conducting signaling studies and biochemical assays in tissues. As an alternative, 3D culture model systems exist in which cell-adhesion dependent tissue architecture, heterotypic cell-cell interactions and tissue differentiation can be recapitulated with good fidelity. 3D cell culture models are slowly revealing how tissue architecture can dramatically influence how a cell responds to exogenous stimuli to modify its apoptotic behavior and hence should prove instrumental for identifying novel cell death pathways.
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Affiliation(s)
- Nastaran Zahir
- Department of Bioengineering and Institute for Medicine and Engineering, 1170 Vagelos Research Laboratory, 3340 Smith Walk, Philadelphia, PA 19104-6383, USA
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Yeung T, Georges PC, Flanagan LA, Marg B, Ortiz M, Funaki M, Zahir N, Ming W, Weaver V, Janmey PA. Effects of substrate stiffness on cell morphology, cytoskeletal structure, and adhesion. ACTA ACUST UNITED AC 2004; 60:24-34. [PMID: 15573414 DOI: 10.1002/cm.20041] [Citation(s) in RCA: 1593] [Impact Index Per Article: 79.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The morphology and cytoskeletal structure of fibroblasts, endothelial cells, and neutrophils are documented for cells cultured on surfaces with stiffness ranging from 2 to 55,000 Pa that have been laminated with fibronectin or collagen as adhesive ligand. When grown in sparse culture with no cell-cell contacts, fibroblasts and endothelial cells show an abrupt change in spread area that occurs at a stiffness range around 3,000 Pa. No actin stress fibers are seen in fibroblasts on soft surfaces, and the appearance of stress fibers is abrupt and complete at a stiffness range coincident with that at which they spread. Upregulation of alpha5 integrin also occurs in the same stiffness range, but exogenous expression of alpha5 integrin is not sufficient to cause cell spreading on soft surfaces. Neutrophils, in contrast, show no dependence of either resting shape or ability to spread after activation when cultured on surfaces as soft as 2 Pa compared to glass. The shape and cytoskeletal differences evident in single cells on soft compared to hard substrates are eliminated when fibroblasts or endothelial cells make cell-cell contact. These results support the hypothesis that mechanical factors impact different cell types in fundamentally different ways, and can trigger specific changes similar to those stimulated by soluble ligands.
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Affiliation(s)
- Tony Yeung
- Institute for Medicine and Engineering, University of Pennsylvania, PA 19104, USA
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12
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Zahir N, Lakins JN, Russell A, Ming W, Chatterjee C, Rozenberg GI, Marinkovich MP, Weaver VM. Autocrine laminin-5 ligates alpha6beta4 integrin and activates RAC and NFkappaB to mediate anchorage-independent survival of mammary tumors. J Cell Biol 2003; 163:1397-407. [PMID: 14691145 PMCID: PMC2173718 DOI: 10.1083/jcb.200302023] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2003] [Accepted: 10/27/2003] [Indexed: 01/15/2023] Open
Abstract
Invasive carcinomas survive and evade apoptosis despite the absence of an exogenous basement membrane. How epithelial tumors acquire anchorage independence for survival remains poorly defined. Epithelial tumors often secrete abundant amounts of the extracellular matrix protein laminin 5 (LM-5) and frequently express alpha6beta4 integrin. Here, we show that autocrine LM-5 mediates anchorage-independent survival in breast tumors through ligation of a wild-type, but not a cytoplasmic tail-truncated alpha6beta4 integrin. alpha6beta4 integrin does not mediate tumor survival through activation of ERK or AKT. Instead, the cytoplasmic tail of beta4 integrin is necessary for basal and epidermal growth factor-induced RAC activity, and RAC mediates tumor survival. Indeed, a constitutively active RAC sustains the viability of mammary tumors lacking functional beta1 and beta4 integrin through activation of NFkappaB, and overexpression of NFkappaB p65 mediates anchorage-independent survival of nonmalignant mammary epithelial cells. Therefore, epithelial tumors could survive in the absence of exogenous basement membrane through autocrine LM-5-alpha6beta4 integrin-RAC-NFkappaB signaling.
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Affiliation(s)
- Nastaran Zahir
- Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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