title: Stiffness of pancreatic cancer cells is associated with increased invasive potential.
abstract: Metastasis is a fundamentally physical process in which cells are required to deform through narrow gaps as they invade surrounding tissues and transit to distant sites. In many cancers, more invasive cells are more deformable than less invasive cells, but the extent to which mechanical phenotype, or mechanotype, can predict disease aggressiveness in pancreatic ductal adenocarcinoma (PDAC) remains unclear. Here we investigate the invasive potential and mechanical properties of immortalized PDAC cell lines derived from primary tumors and a secondary metastatic site, as well as noncancerous pancreatic ductal cells. To investigate how invasive behavior is associated with cell mechanotype, we flow cells through micron-scale pores using parallel microfiltration and microfluidic deformability cytometry; these results show that the ability of PDAC cells to passively transit through pores is only weakly correlated with their invasive potential. We also measure the Young's modulus of pancreatic ductal cells using atomic force microscopy, which reveals that there is a strong association between cell stiffness and invasive potential in PDAC cells. To determine the molecular origins of the variability in mechanotype across our PDAC cell lines, we analyze RNAseq data for genes that are known to regulate cell mechanotype. Our results show that vimentin, actin, and lamin A are among the most differentially expressed mechanoregulating genes across our panel of PDAC cell lines, as well as a cohort of 38 additional PDAC cell lines. We confirm levels of these proteins across our cell panel using immunoblotting, and find that levels of lamin A increase with both invasive potential and Young's modulus. Taken together, we find that stiffer PDAC cells are more invasive than more compliant cells, which challenges the paradigm that decreased cell stiffness is a hallmark of metastatic potential.
authors.affiliation: Department of Integrative Biology and Physiology, University of California, Los Angeles, USA. rowat@ucla.edu.
authors.forename: Angelyn V
authors.initials: AV
authors.lastname: Nguyen
authors.affiliation: Department of Integrative Biology and Physiology, University of California, Los Angeles, USA. rowat@ucla.edu and Department of Bioengineering, University of California, Los Angeles, USA.
authors.forename: Kendra D
authors.initials: KD
authors.lastname: Nyberg
authors.affiliation: Department of Integrative Biology and Physiology, University of California, Los Angeles, USA. rowat@ucla.edu.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Scott
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, USA.
authors.forename: Alia M
authors.initials: AM
authors.lastname: Welsh
authors.affiliation: Department of General Surgery, University of California, Los Angeles, USA.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Nguyen
authors.affiliation: Department of General Surgery, University of California, Los Angeles, USA.
authors.forename: Nanping
authors.initials: N
authors.lastname: Wu
authors.affiliation: Asylum Research, an Oxford Instruments Company, Santa Barbara, California, USA.
authors.forename: Sophia V
authors.initials: SV
authors.lastname: Hohlbauch
authors.affiliation: Asylum Research, an Oxford Instruments Company, Santa Barbara, California, USA.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Geisse
authors.affiliation: Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Ewan A
authors.initials: EA
authors.lastname: Gibb
authors.affiliation: Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: A Gordon
authors.initials: AG
authors.lastname: Robertson
authors.affiliation: Department of General Surgery, University of California, Los Angeles, USA and Jonsson Comprehensive Cancer Center, University of California, Los Angeles, USA.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Donahue
authors.affiliation: Department of Integrative Biology and Physiology, University of California, Los Angeles, USA. rowat@ucla.edu and Department of Bioengineering, University of California, Los Angeles, USA and Jonsson Comprehensive Cancer Center, University of California, Los Angeles, USA.
authors.forename: Amy C
authors.initials: AC
authors.lastname: Rowat
mesh_terms: D015415:Biomarkers; D021441:Carcinoma, Pancreatic Ductal; D045744:Cell Line, Tumor; D002469:Cell Separation / Q000379:methods; D055119:Elastic Modulus; D005434:Flow Cytometry / Q000379:methods*; D006244:Hardness; D006245:Hardness Tests / Q000379:methods*; D006801:Humans; D056656:Lab-On-A-Chip Devices; D018625:Microscopy, Atomic Force / Q000379:methods*; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D013314:Stress, Mechanical; D014462:Ultrafiltration / Q000379:methods*
chemical_list: D015415:Biomarkers