Cited by 5Mathematical Biology Tumor GrowthCellular Mechanics and InteractionsCancer Cells and Metastasis

Inference of weak-form partial differential equations describing migration and proliferation mechanisms in wound healing experiments on cancer cells

Open access
Srivastava, Siddhartha, Kinnunen, Patrick C., Wang, Zhenlin, Ho, Kenneth K.Y., Humphries, Brock A., Chen, Siyi, Linderman, Jennifer J., Luker, Gary D. +2 more·2025·PLOS Computational Biology

Abstract

Cancer metastasis, which requires migration of cancer cells away from the primary tumor, is responsible for approximately 65% percent of cancer-related deaths. Therefore, targeting signaling pathways that drive cancer cell migration or proliferation is a common therapeutic approach. Cell migration is commonly studied using experimental approaches which track cells or cell monolayers as they evolve over time. Computational modeling can then be used to fit partial differential equation (PDE) models to the data, providing mechanistic insights underlying the observed cell motion, including the contribution of various cellular behaviors such as random motion, directed motion, and cell division. A popular experimental technique, the scratch assay, measures the migration and proliferation-driven cell closure of a scratch in a confluent cell monolayer. However, these assays do not disambiguate between different drivers of scratch closure (for instance between cell proliferation and migration to open space). To improve analysis of this technique, we combine scratch assays, video microscopy, and PDE inference to gain quantitative insight to mechanisms of cell migration and proliferation. We capture the evolution of cell density fields over time using live-cell microscopy and automated image processing. Our PDE inference methods involve the use of weak form-based system identification techniques for cell density dynamics modeled with advection-diffusion-reaction systems. We then compare our method with recent modeling work, finding that our model discovery tool automatically identifies similar models including reaction and diffusion terms from a larger set of bases. We demonstrate the application of this framework on 2-dimensional scratch assays subject to the inhibiting effect of trametinib on wound closure and characterize the results in the context of the quantified uncertainty in our inference approach. Our integrated experimental and computational pipeline can be used to rapidly identify and refine models of cell migration in a variety of contexts, enabling the quantitative measurement of the effect of drugs and other perturbations on cell migration and proliferation with uncertainty accounted for.

AI snapshot

Written from the paper’s full text.

TL;DR

The paper develops a weak-form variational system identification pipeline, followed by PDE-constrained optimization, to infer advection-diffusion-reaction PDEs from scratch-wound healing assays. Applied to 1D PC-3 data and 2D MDA-MB-231 breast cancer assays, it identifies parsimonious reaction-diffusion models and quantifies trametinib effects on random migration and proliferation.

Key findings

  • In 1D PC-3 scratch data, inferred 3-term models excluded advection and had constant diffusivity plus linear or quadratic reaction terms; for four of six initial seeding densities, RMSEs were significantly lower than those reported by Jin et al., and for two they were similar.
  • In 2D MDA-MB-231 assays, the Variational System Identification loss was essentially constant for two-term diffusion-plus-reaction models and increased only for models lacking reaction terms; the adopted three-term models for untreated and 100 nM trametinib had constant diffusivity and linear/quadratic reaction terms.
  • The inferred reaction rate was positive at low cell density and became negative above a critical density, interpreted as crowding-induced death; untreated diffusivity was around 50 μm²/hr and decreased with trametinib.
  • Low levels of trametinib inhibited wound closure primarily by decreasing random cell migration by approximately 20%; higher concentrations did not further inhibit migration, and RMSEs across conditions averaged about 13% of maximum cell concentrations.

Methods

  • MDA-MB-231 H2B-mCherry cells were seeded at 50,000 cells/well in 24-well glass-bottom plates, grown to confluence (~36 h), scratched with a p200 tip, and imaged every 20 min for 24–48 h; treatments included five trametinib concentrations from 10 μM to 100 nM and an untreated control. Automated image processing thresholded nuclear images, extracted centroids, binned positions (50–100 μm), and smoothed spatially (150 μm) and temporally (3 h 40 min) to obtain cell density fields C(x,t).
  • The 1D validation used previously published PC-3 scratch assay data from Jin et al., with initial seeding from 10,000 to 20,000 cells in 2,000-cell steps, density measured every 12 h for 48 h and averaged across three replicates.
  • Inference used the weak form of an advection-diffusion-reaction PDE with density-dependent D(C), vf(C), and r(C) up to quadratic order, discretized by finite elements in FEniCS; stepwise regression selected parsimonious terms, followed by PDE-constrained optimization with adjoint-based gradients/BFGS via dolfin-adjoint. The 2D mesh had 6,478 linear triangular elements, and 1D forward solutions used 42 linear elements.

Limitations

  • Paper-stated: inference proceeds by model selection from a candidate library, not by de novo discovery; future work aims to address experiments that may not resolve length scales with sufficiently high cell densities for continuum predictions and sparse data; at higher cell densities, Maxwell-Stefan diffusion may be more appropriate.
  • Paper-stated: in the 1D 18,000-cell case, the data were not sufficiently sensitive to the diffusive mechanism, requiring expansion to a four-term model.
  • Evident from the text: 2D experiments imaged one region of the scratch per well and did not track individual cells between frames; 2D results are from MDA-MB-231 cells only, and 1D validation from PC-3 cells, so generalizability across cell lines and conditions is not established here.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1371/journal.pcbi.1013607

Cites

61 of 63 references verified0 citation errors · 2 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

31 of 36 cited sources checked · 1 supported · 3 flagged · accuracy not yet measured

  • Premisecitation

    The dataset, collected by Jin et al., consists of scratch assays performed on PC-3 prostate cancer cells with varying initial confluence prior to the scratch.

    “The dataset, collected by Jin et al.,8 consists of scratch assays performed on PC-3 prostate cancer cells with varying initial confluence prior to the scratch.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [8] NH Gopee, 2024, A prenatal skin atlas reveals immune regulation of human skin morphogenesis, Nature. source

      The Methods section, “Scratch wound assay of fibroblasts in co-culture with macrophages” (page unavailable), describes assays using skin-organoid-derived fibroblasts and macrophages, not PC-3 prostate cancer cells. It specifies a 5:1 seeding ratio and does not describe varying initial confluence. (LLM, conf=0.89)

      Checked by a reasoning model — may be wrong.

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  • Findingcitation

    Variational System Identification rapidly identified an accurate model describing the evolution of cell concentration over time for a variety of initial seeding densities, with accuracy that matched or improved upon results in the literature.

    “With it, we were able to rapidly identify an accurate model describing the evolution of cell concentration over time for a variety of initial seeding densities with accuracy that matched or improved upon results in the literature8.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [8] NH Gopee, 2024, A prenatal skin atlas reveals immune regulation of human skin morphogenesis, Nature. source

      Split into 2 atoms — 0 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.

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  • Findingown data

    Low levels of trametinib inhibit wound closure primarily by decreasing random cell migration by approximately 20%.

    “We demonstrate the application of this pipeline on high throughput 2-dimensional scratch assays and find that low levels of trametinib inhibit wound closure primarily by decreasing random cell migration by approximately 20%.”
    Quote in the paperSubstantial claim
  • Findingown data

    Variational System Identification successfully identified mechanisms of advection, diffusion and proliferation of cells in 2-D scratch assays by inferring the governing PDEs.

    “We found that Variational System Identification could successfully identify mechanisms of advection (directed motion), diffusion (random motion) and proliferation of cells in 2-D scratch assays by inferring the governing PDEs.”
    Quote in the paperSubstantial claim
  • Findingown data

    The inferred reaction rate has a non-linear functional dependence on cell density: positive at low cell densities and becoming negative above a critical density, i.e., cell death sets in.

    “This combination of techniques reveals a non-linear functional dependence of cell proliferation (reaction in the PDE) rate on cell density: positive at low cell densities and becoming negative above a critical density; i.e., cell death sets in(Fig. 6D).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The reaction term in the PDE corresponds to cell proliferation and death rather than other density-dependent processes.
  • Classified as probably not a substantial claim. 16
  • May combine two claims. 17
  • The quote only partly states this claim. 1
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Variational System Identification has been applied to identify governing equations for the evolution of materials, the spatiotemporal spread of COVID-19, and constitutive models of soft materials.

    “Variational System Identification has been applied to identify governing equations for the evolution of materials17,20,19, the spatiotemporal spread of COVID-1921,18, as well as constitutive models of soft materials22,23.”
    Quote in the paperNot a substantial claim7 of 7 sources checked
    • cites [17] MJ Simpson, 2017, Quantifying the roles of random motility and directed motility using advection-diffusion theory for a 3T3 fibroblast cell migration assay stimulated with an electric field, BMC Syst Biol. source

      The Background and Methods > Modelling methods sections describe a 3T3 fibroblast migration assay using an advection–diffusion model. Our copy does not address Variational System Identification or its applications to material evolution, COVID-19 spread, or soft-material constitutive models (searched those terms); page numbers were not available. (LLM, conf=0.77)

      Experimental — accuracy not yet measured
    • cites [20] NM Mangan, 2016, Inferring biological networks by sparse identification of nonlinear dynamics, IEEE Trans. Mol. Biol. Multi-Scale Commun. source

      The Conclusions describe implicit-SINDy applied to three biological models, while the SINDy section discusses identifying governing equations from data. Neither section addresses Variational System Identification applied to materials evolution, COVID-19 spread, or soft-material constitutive models; searches for those applications found no supporting passage in our copy. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
    • cites [19] SL Brunton, 2016, Discovering governing equations from data by sparse identification of nonlinear dynamical systems, Proc Natl Acad Sci. source

      Section 3 (p. 4) identifies the paper’s method as sparse identification of nonlinear dynamics (SINDy), not Variational System Identification. The Abstract (p. 1) lists demonstrations on oscillators, the Lorenz system, and fluid vortex shedding; it does not report the claimed applications to materials, COVID-19, or soft-material constitutive models. (LLM, conf=0.86)

      Checked by a reasoning model — may be wrong.

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    • cites [21] SH Rudy, 2017, Data-driven discovery of partial differential equations, Sci Adv. source

      The Introduction and Materials and Methods describe discovering governing PDEs through sparse regression, not applications of Variational System Identification to materials, COVID-19, or soft-material constitutive models. Searches for those applications found no passage addressing them in our copy (page numbers unavailable). (LLM, conf=0.76)

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    • cites [18] KKY Ho, 2023, Oscillatory ERK signaling and morphology determine heterogeneity of breast cancer cell chemotaxis via MEK-ERK and p38-MAPK signaling pathways, Bioengineering (Basel). source

      The cited paper’s Methods §2.7 applies Variational System Identification to breast-cancer cell migration, not to constitutive models of soft materials. Its References identify a separate Wang et al. (2021) paper on inferring the constitutive response of soft-material surrogates using that method; that is the work matching the clause to which this citation is attached. (LLM, conf=0.84) It matches “Inference of deformation mechanisms and constitutive response of soft material surrogates of biological tissue by full-field characterization and data-driven variational system identification” (2021) instead.

      Checked by a reasoning model — may be wrong.

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    • cites [22] M Quade, 2018, Sparse identification of nonlinear dynamics for rapid model recovery, Chaos. source

      The citation to this paper is attached to the COVID-19 application. The introduction (p. 1) mentions epidemiology only as a general example of a complex system, while the conclusions (p. 8) describe numerical demonstrations of abrupt-SINDy, not Variational System Identification. Our copy contains no account of identifying equations for the spatiotemporal spread of COVID-19 (searched for Variational System Identification, COVID-19, and epidemiology). (LLM, conf=0.76)

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    • cites [23] KP Champion, 2019, Discovery of nonlinear multiscale systems: Sampling strategies and embeddings, SIAM J Appl Dyn Syst. source

      The Abstract (p. 1) and Discussion (p. 17) describe SINDy and HAVOK methods for discovering dynamical systems, not applications of Variational System Identification to the listed subjects. Searches for variational identification, materials, and COVID-19 found no passage in our copy addressing those applications. (LLM, conf=0.77)

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    Premisecitation

    Variational System Identification extends SINDy to inferring PDEs in weak form, thereby offering advantages in the presence of noise and high derivatives.

    “It extends the popular SINDy approach12,13,14,15,16 to inferring PDEs in weak form, thereby offering advantages in the presence of noise and high derivatives17,18,19.”
    Quote in the paperSubstantial claim3 of 3 sources checked
    • cites [17] MJ Simpson, 2017, Quantifying the roles of random motility and directed motility using advection-diffusion theory for a 3T3 fibroblast cell migration assay stimulated with an electric field, BMC Syst Biol. source

      The Background and Modelling methods passages describe an advection-diffusion model for cell migration, not Variational System Identification. Searches for SINDy, weak-form PDE inference, noise, and high derivatives found no passage addressing the attributed claim. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
    • cites [18] KKY Ho, 2023, Oscillatory ERK signaling and morphology determine heterogeneity of breast cancer cell chemotaxis via MEK-ERK and p38-MAPK signaling pathways, Bioengineering (Basel). source

      Section 2.7 (page unavailable) says the authors used VSI to infer mechanisms and parameters of an advection–diffusion PDE. It does not say that VSI extends SINDy, uses a weak form, or offers advantages with noise or high derivatives; searches for those terms found no supporting passage. (LLM, conf=0.85)

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    • cites [19] SL Brunton, 2016, Discovering governing equations from data by sparse identification of nonlinear dynamical systems, Proc Natl Acad Sci. source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    First-principles modeling has established a variety of PDE models that accurately represent the behavior of scratch assays with a high density of cells and under a variety of conditions.

    “First-principles modeling has established a variety of partial differential equation (PDE) models that accurately represent the behavior of scratch assays with a high density of cells and under a variety of conditions8,9.”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [8] NH Gopee, 2024, A prenatal skin atlas reveals immune regulation of human skin morphogenesis, Nature. source

      The Methods section describes a fibroblast–macrophage scratch assay and its image-based analysis, but does not discuss PDE models of scratch assays. Searches for first-principles PDE modeling and cell-density-dependent scratch-assay models found no passage addressing the claimed modeling results. (LLM, conf=0.76)

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    • cites [9] PF Renz, 2024, In vivo single-cell CRISPR uncovers distinct TNF programmes in tumour evolution, Nature. source

      The Methods > Scratch assay passage describes an experimental cell-gap assay and image analysis, not a mathematical model. Searches for PDE models and first-principles modeling found no passage in our copy addressing whether such models accurately represent high-density scratch assays under varied conditions; page numbers were not provided. (LLM, conf=0.76)

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    Premisecitation

    By estimating parameters for these models, past work has helped identify quantitative effects of biological perturbations in scratch assays.

    “By estimating parameters for these models, past work has helped identify quantitative effects of biological perturbations in scratch assays8,10,11.”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites [8] NH Gopee, 2024, A prenatal skin atlas reveals immune regulation of human skin morphogenesis, Nature. source

      The ‘Scarless healing and potential macrophage contribution’ section reports that macrophage co-culture improved scratch wound-width closure over 72 hours, supporting a measured effect of a biological perturbation. The Methods section says the scratch images were analysed with an ImageJ macro and two-way ANOVA; it does not describe estimating parameters of a scratch-assay model to identify that effect. Page numbers are unavailable in our copy. (LLM, conf=0.85)

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    • cites [10] M Vang Mouritzen, 2018, Optimized scratch assay for in vitro testing of cell migration with an automated optical camera, JoVE. source
    • cites [11] W Jin, 2016, Reproducibility of scratch assays is affected by the initial degree of confluence: Experiments, modelling and model selection, J Theor Biol. source
  • May combine two claims.

    Premisecitation

    Lagergren et al. inferred density-dependent reaction-diffusion equations for cell migration and identified non-linear functions of concentration for diffusivity and reaction terms that vary with initial seeding concentration, consistent with our findings.

    “Lagergren et al. demonstrated the power of this approach on the Jin et al. dataset8 (also analyzed by Jin et al.), when they inferred density-dependent reaction-diffusion equations for cell migration10. They identified non-linear functions of concentration for diffusivity and reaction terms, and found that these functions vary with initial seeding concentration, consistent with our findings.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [8] NH Gopee, 2024, A prenatal skin atlas reveals immune regulation of human skin morphogenesis, Nature. source

      Split into 2 atoms — 0 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites [10] M Vang Mouritzen, 2018, Optimized scratch assay for in vitro testing of cell migration with an automated optical camera, JoVE. source
  • May combine two claims.

    Findingown data

    The cell densities achieved in our MDA-MB-231 scratch assays are comparable to those observed by Jin et al. and admit treatment using continuum advection-diffusion-reaction PDEs.

    “As seen in Fig. 6A, the cell densities achieved are comparable to those observed by Jin et al.,8 and admit treatment of the problem using continuum advection-diffusion-reaction PDEs.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [8] NH Gopee, 2024, A prenatal skin atlas reveals immune regulation of human skin morphogenesis, Nature. source

      The Methods section describes scratch assays using skin-organoid-derived fibroblasts and macrophages, but gives no cell densities comparable to the citing paper's MDA-MB-231 assays. Searches for MDA-MB-231, Jin, and advection-diffusion-reaction PDEs found no passage addressing the attributed comparison or modeling rationale; no page number is available in our copy. (LLM, conf=0.77)

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    Premisecitation

    Our past study showed that trametinib reduces both random and directed motion in chemotaxis.

    “Our past study showed that trametinib reduces both random and directed motion in chemotaxis35.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [35] PC Kinnunen, 2022, Computational modeling implicates protein scaffolding in p38 regulation of Akt, J Theor Biol. source

      The Results section describes kinase activity and responses to CXCL12 or EGF, while Methods > Cell imaging lists p38 inhibitors and anisomycin as treatments. Searches for trametinib and for random and directed motion in chemotaxis found no passage addressing the claimed effect. (LLM, conf=0.75)

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    Premisecitation

    Previous computational analyses of cell migration have identified diffusivity values from approximately 50 to 3000 μm2/hr.

    “Previous computational analyses of cell migration have identified a wide range of diffusivity values, from approximately 50 to 3000μm2/hr9,40,41.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [9] PF Renz, 2024, In vivo single-cell CRISPR uncovers distinct TNF programmes in tumour evolution, Nature. source

      The Methods describe a scratch assay that images cells over 22 hours, but give no diffusivity estimates. Searches for the 50–3000 μm²/hr range and computational analyses of cell migration found no passage in our copy that addresses the claimed values. (LLM, conf=0.76)

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    • cites [40] S Mitusch, 2019, dolfin-adjoint 2018 .1: Automated adjoints for FEniCS and Firedrake, JOSS. source

      The Abstract describes software for deriving adjoint models for FEniCS and Firedrake; it does not discuss cell migration or report diffusivity values. Searches for cell-migration diffusivity and the 50–3000 μm²/hr range found no passage addressing the claim. No page number is provided in our copy. (LLM, conf=0.78)

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    • cites [41] Funke SW, Farrell PE. A framework for automated pde-constrained optimisation. ArXiv; 2013. source

      The Introduction (p. 2) discusses PDE-constrained optimisation, and the wetting-and-drying example (pp. 21–23) concerns tsunami modelling. Searches for cell migration, diffusivity, and the stated range found no passage reporting cell-migration diffusivity values. (LLM, conf=0.76)

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    Premisecitation

    Scratch assays have been miniaturized and mechanized, making them compatible with high-throughput screening.

    “Scratch assays have been miniaturized and mechanized, making them compatible with high-throughput screening45,46.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [45] H Narayanan, 2010, In silico estimates of the free energy rates in growing tumor spheroids, J Phys Condens Matter. source

      The Experimental methods section (pp. 8–9) describes growing and imaging tumor spheroids in hydrogels, not scratch assays. Searches for miniaturized or mechanized scratch assays and high-throughput wound-healing screening found no passage in our copy addressing the claim. (LLM, conf=0.76)

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    • cites [46] K Garikipati, 2017, Perspectives on the mathematics of biological patterning and morphogenesis, J Mech Phys Solids. source

      The passages from section 1.1 (pp. 3–6) discuss biological patterning and models of cell migration, not scratch assays. Searches for scratch assays, miniaturization, mechanization, and high-throughput screening found no passage in our copy addressing the claim. (LLM, conf=0.76)

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The treatment of cell migration via continuum PDEs is well established in biophysics, as is the role of cell arrangement in determining aspects of the progression of cancers.

    “The treatment of cell migration via continuum PDEs is well established in biophysics36,37,38, as is the role of cell arrangement in determining aspects of the progression of cancers39.”
    Quote in the paperNot a substantial claim2 of 4 sources checked
    • cites [36] ST Vittadello, 2019, Mathematical models incorporating a multi-stage cell cycle replicate normally-hidden inherent synchronization in cell proliferation, J R Soc Interface. source

      The Introduction discusses mathematical models of cell proliferation, and §2.2 uses differential equations for cell-cycle-stage populations. Our copy does not address continuum PDE models of cell migration or the effect of cell arrangement on cancer progression; searches for those terms found no supporting passage. (LLM, conf=0.75)

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    • cites [37] TJ Hughes, 2003

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [38] A Logg, 2010, DOLFIN, ACM Trans Math Softw. source

      The citation is attached to the first clause, about continuum-PDE treatment of cell migration; citation 39 is attached separately to the cancer claim. The Introduction describes PDEs generally, and §5.3 gives a convection–diffusion example, but neither addresses cell migration or its established use in biophysics. Searches for cell migration and biophysics found no relevant passage in our copy. (LLM, conf=0.76)

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    • cites [39] A Logg, 2012 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Cell morphology and fluorescent reporters have been used to measure or infer cell states in migrating cells.

    “Cell morphology42 and fluorescent reporters44 have been used to measure or infer cell states in migrating cells.”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [42] S Srivastava, 2024, Pattern formation in dense populations studied by inference of nonlinear diffusion-reaction mechanisms, Numer Meth Eng. source

      The Introduction discusses cellular migration, and the Abstract describes inferring diffusion–reaction models from spatiotemporal data. Neither passage addresses using cell morphology or fluorescent reporters to measure or infer states in migrating cells. Searches for those measurement methods found no relevant passage in our copy. (LLM, conf=0.72)

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    • cites [44] A Akinleye, 2013, MEK and the inhibitors: From bench to bedside, J Hematol Oncol. source

      Citation 44 is attached to the fluorescent-reporters part of the sentence, not to cell morphology. The Introduction and MEK proteins sections discuss MAPK signaling and cell motility, but no passage found describes fluorescent reporters being used to measure or infer states in migrating cells (searched: fluorescent reporters, fluorescence, reporter assay, migration). (LLM, conf=0.76)

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    Premisecitation

    MEK kinase is known to regulate cell migration and proliferation.

    “MEK kinase is known to regulate cell migration and proliferation34.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [34] PC Spinosa, 2019, Short-term cellular memory tunes the signaling responses of the chemokine receptor CXCR4, Sci Signal. source

      The Introduction (page unavailable) says that ERK and Akt mediate cell proliferation and chemotaxis, and the Materials and Methods section places MEK upstream of ERK. This supports a pathway-level connection, but the paper does not specifically establish that MEK itself regulates cell migration and proliferation. (LLM, conf=0.78)

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    Premisecitation

    At higher cell densities, more rigorous models such as Maxwell-Stefan diffusion would be more appropriate.

    “In this work, we considered a polynomial cell concentration dependence in the diffusivity for modeling nonlinear diffusion, but at higher cell densities, more rigorous models, such as Maxwell-Stefan diffusion would be more appropriate33.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [33] PC Spinosa, 2020, Pre-existing cell states control heterogeneity of both EGFR and CXCR4 signaling, Cell Mol Bioeng. source

      The Materials and Methods describe an ordinary-differential-equation model of EGFR and CXCR4 signaling, not a cell-concentration-dependent diffusion model. Searches for Maxwell–Stefan diffusion and polynomial diffusivity found no passage addressing whether a different diffusion model is appropriate at higher cell densities. The passages provide section labels but no page numbers. (LLM, conf=0.78)

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    Premisecitation

    There exist models that have considered density-dependent effects on migration and on cell proliferation.

    “There exist models that have considered density-dependent effects on migration, for instance representing cells interacting with each other, and on cell proliferation, for instance, modeling its saturation at high cell density8,27.”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [8] NH Gopee, 2024, A prenatal skin atlas reveals immune regulation of human skin morphogenesis, Nature. source

      The Methods sections on spatial data analysis and trajectory analysis describe models for estimating cell abundance and cell-state transitions, not models of density-dependent migration or proliferation. Searches for high-density proliferation saturation and density-dependent migration found no passage addressing either point in our copy. (LLM, conf=0.75)

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    • cites [27] Z Wang, 2021, System inference via field inversion for the spatio-temporal progression of infectious diseases: Studies of COVID-19 in Michigan and Mexico, Arch Comput Methods Eng. source

      The Introduction and Results discuss population-density gradients and mobility in a COVID-19 model, not cell migration or proliferation. Searches for density-dependent migration, cell interactions, and proliferation saturation found no passage in our copy addressing the attributed claim. (LLM, conf=0.74)

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  • May combine two claims.

    Findingown data

    The Variational System Identification loss function is essentially constant for two-term models including diffusion and reaction terms, and only starts to increase for models that lack reaction terms.

    “We observed that the Variational System Identification loss function is essentially constant for two-term models including diffusion and reaction terms, and only starts to increase for models that lack reaction terms (Fig. 6B).”
    Quote in the paperSubstantial claim
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    Findingreasoning

    Reaction and diffusion terms were identified underlying the observed behavior and consistent with previous results.

    “Reaction and diffusion terms were identified underlying the observed behavior and consistent with previous results.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    All resulting optimized models have a constant diffusivity term, and either a linear or quadratic dependence on concentration.

    “All the resulting optimized models have a constant diffusivity term, and either a linear or quadratic dependence on concentration.”
    Quote in the paperSubstantial claim
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    Findingown data

    In the 2D wound healing experiments, we estimate diffusivity values for breast cancer cells around 50 μm2/hr in untreated conditions, with decreasing diffusivity in response to trametinib.

    “In this setting, we estimate diffusivity values for breast cancer cells around 50μm2/hr in untreated conditions, with decreasing diffusivity in response to trametinib.”
    Quote in the paperSubstantial claim
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    Findingown data

    For four of the six initial seeding densities, our models have root mean squared errors significantly lower than the RMSE reported by Jin et al., and for two of the six cases they are similar.

    “We found that for four of the six initial seeding densities, our models have root mean squared errors (RMSEs) that are significantly lower than the RMSE reported by Jin et al. and for two of the six cases they are similar (Fig. 4).”
    Quote in the paperSubstantial claim
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    Premisereasoning

    Physics-informed neural networks can learn relationships to make predictions without any guarantee that the growth or diffusivities learned are physically realizable.

    “However, in such approaches, neural networks can learn relationships to make predictions without any guarantee that the growth or diffusivities learned are physically realizable.”
    Quote in the paperSubstantial claim
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    Premisereasoning

    Variational System Identification and SINDy use weak and strong forms of differential equations in regression-based approaches, and therefore do not require repeated forward evaluations of the model, unlike traditional PDE-constrained inverse modeling, substantially reducing computational cost.

    “Variational System Identification and SINDy respectively use the weak and strong forms of differential equations in regression-based approaches, and therefore do not require repeated forward evaluations of the model, unlike traditional PDE-constrained inverse modeling. This substantially reduces the computational cost.”
    Quote in the paperSubstantial claim
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    Premisenone given

    Smoothing the data alleviates numerical noise in the calculation of derivatives.

    “Thus smoothing the data alleviates numerical noise in the calculation of derivatives.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Neural networks can learn arbitrary relationships between cell density and diffusivity or reaction, but there is no guarantee that physically realizable diffusivity or reaction relationships are learnt unless physics-based constraints are built in.

    “In the case of cell migration, while the neural networks can learn arbitrary relationships between cell density and diffusivity or reaction, there is no guarantee that physically realizable diffusivity or reaction relationships are learnt, unless a number of physics-based constraints are built in.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisenone given

    In Variational System Identification, the equations learned are confined to the candidate library terms used, while neural networks can learn arbitrary relationships for equation parameters to best fit the data.

    “In Variational System Identification, the equations learned are confined to the candidate library terms used, while neural networks can learn arbitrary relationships for equation parameters to best fit the data.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisenone given

    PDE-constrained optimization with adjoint-based gradient computation does not change the selected operators but generates a new set of parameter values that fit the data better than those obtained by Variational System Identification with stepwise regression.

    “PDE-constrained optimization with adjoint-based gradient computation does not change the selected operators but generates a new set of parameter values, which fit the data better than the those obtained by Variational System Identification with stepwise regression.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given

    PINNs can discover relationships that maximize the fit to data, while Variational System Identification sacrifices fitting to data because it is constrained to selected terms which the modeler can ensure are physically meaningful.

    “PINNs can discover relationships that maximize the fit to data, while Variational System Identification sacrifices fitting to data because it is constrained to selected terms which the modeler can ensure are physically meaningful.”
    Quote in the paperNot a substantial claim
  • May combine two claims. The quote only partly states this claim.

    Premisereasoning

    The weak form of the PDE limits the maximum order of derivative evaluated on the data field to first order, which enhances the robustness of the inference against noise in the data field.

    “This choice enhances the robustness of the inference against noise in the data field.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Premisereasoning

    Variational System Identification enables the modeler to restrict the candidate mechanisms and their mathematical forms to those that rigorously encode physical mechanisms.

    “Variational System Identification, on the other hand, enables the modeler to restrict the candidate mechanisms and their mathematical forms to those that rigorously encode physical mechanisms.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationown data

    The models inferred with and without trametinib suggest that even 100 nM trametinib causes a decrease in random cell migration and cell proliferation.

    “The models inferred with and without trametinib suggest that even 100 nM trametinib causes a decrease in random cell migration and cell proliferation.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The candidate library of constant, linear, and quadratic terms for diffusion, advection, and reaction contains the mechanisms needed to describe the observed cell migration dynamics.
29 of 29
  • The paper relies on this without support.

    Scratch assays do not measure dynamic effects.

    “These assays do not measure dynamic effects.”
  • The paper relies on this without support.

    Typically, the complexity of cell migration in scratch assays is reduced to a single number, which represents the amount of space filled in a given time or the distance traveled by the leading edge of cells.

    “However, typically the complexity of cell migration is reduced to a single number, which represents the amount of space filled in a given time or the distance traveled by the leading edge of cells.”
  • The paper relies on this without support.

    The candidate library of constant, linear, and quadratic terms for diffusion, advection, and reaction contains the mechanisms needed to describe the observed cell migration dynamics.

    “We used the same library of candidate operators, including constant, linear, and quadratic terms for diffusion and advection, and linear and quadratic terms for reaction.”
  • The paper relies on this without support.

    The reaction term in the PDE corresponds to cell proliferation and death rather than other density-dependent processes.

    “This combination of techniques reveals a non-linear functional dependence of cell proliferation (reaction in the PDE) rate on cell density: positive at low cell densities and becoming negative above a critical density; i.e., cell death sets in(Fig. 6D).”
4 of 4

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Matrix residual reverses the signs of the time-derivative and diffusion terms

    Major

    Equation (9) gives the residual positive time-derivative and diffusion terms. Equations (11), (12), and (14) instead put a negative time-derivative term in y and subtract a positive diffusion column from it, reversing both signs.

  • Advection library columns retain the velocity they are meant to parameterize

    Minor

    Equation (10b) defines vf through coefficients θ3-θ5, but equation (15) includes vf inside the columns corresponding to those coefficients. That makes those columns depend on the unknown coefficients, contrary to the stated matrix-vector regression R=y−Ξ⋅θ.

2 of 2

Cites

Flagged first, then by citations

2 of the 60 references couldn’t be matched to a known paper.

Cited by

Sorted by citations

Authors
Srivastava, S., Kinnunen, P. C., Wang, Z., Ho, K. K. Y., Humphries, B. A., Chen, S., Linderman, J. J., Luker, G. D., Luker, K. E., & Garikipati, K.
Affiliations
  • University of Southern California (US)
  • University of Michigan (US)
Corresponding author
Garikipati, Krishna
Venue
PLOS Computational Biology
Published
2025-10-28
Volume
21
Issue
10
Pages
e1013607
ISSN
  • 1553-734X (ISSN-L)
  • 1553-7358
OpenAlex
W4404122244
Cited by
5
References
60
Citations by year
2026: 4 · 2024: 1
FWCI
3.06
Type
journal article
Language
en
Open access
Locations
  • PLoS Computational Biology (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion, cc-by-nc-sa)
  • Europe PMC (PubMed Central) (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • National Institutes of Health, United States (R01CA238042, R50CA221807, R01CA238023, R33CA225549, R37CA222563, R21AI173559)
  • W. M. Keck Foundation (N.A.)
Topics
  • Physical Sciences › Mathematics › Modeling and Simulation › Mathematical Biology Tumor Growth
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Cellular Mechanics and Interactions
  • Health Sciences › Medicine › Oncology › Cancer Cells and Metastasis
Keywords
tumor cell migration, cell proliferation, wound healing, scratch assay, reaction-diffusion-advection model, trametinib, metastasis, model uncertainty, live-cell imaging

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-14.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-14.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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