# HOW CANCER CELLS DEFORM 3D ENVIRONMENTS

Valérie M. Laurent, Arnold Fertin, Y. Usson, Claude Verdier

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Valérie M. Laurent, Arnold Fertin, Y. Usson, Claude Verdier. HOW CANCER CELLS DEFORM 3D ENVIRONMENTS. 29th Congress of the European Society of Biomechanics, ESB, Jun 2024, Edinburgh, France. hal-05345046

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Submitted on 15 Nov 2025

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Distributed under a Creative Commons Attribution 4.0 International License
# HOW CANCER CELLS DEFORM 3D ENVIRONMENTS

Valérie M. Laurent (1), Arnold Fertin (2), Yves Usson (2) and Claude Verdier (1)

## Introduction

Cell migration plays a key role in various physiological/pathological phenomena such as wound healing, cancer metastasis or embryogenesis. Until now, many studies have focused on migration on 2D substrates but less is known about migration in 3D environments. The aim of our study is precisely to analyze cancer cell migration in 3D fibrous collagen gels using reflectance confocal microscopy [1]. Reflectance microscopy allows to simultaneously visualize the position of collagen fibers and the actin cytoskeleton of transfected cells, and thus to establish the link between the collagen fiber displacement field and the cell morphology.

## Methods

Three bladder cancer cell lines (RT112, T24 and J82) were used and cultured in RPMI culture medium. These lines show increasing levels of invasiveness according to their grade and stage (RT112<T24<J82) [2]. These cell lines were transfected with the Life-Act GFP plasmid to stain for F-actin.

Gels (0.95 mg/mL) were prepared from rat tail collagen solutions (Corning, USA) and mixed with culture medium, then neutralized to reach pH=7.4 at 4°C. Then, cells were added to the collagen before polymerization at 37°C for 30 min.

The visualization of collagen fibers and actin cytoskeleton of cancer cells was performed with the reflectance and fluorescence modes of a confocal microscope (Zeiss, LSM 510 model).

The 3D position of the collagen fibers were determined using a phase-only correlation (POC) [3]. First, we calculated the function POC :

$$r(\boldsymbol{x}) = \mathcal{F}^{-1} \left( \frac{I_1^*(\omega) * I_2(\omega)}{|I_1^*(\omega) * I_2(\omega)|} \right)$$

where $i_1(x,t)$ is the image intensity at time t and position x, $I_1(\omega)$ the Fourier transform of $i_1$, $\mathcal{F}^{-1}$ the inverse Fourier transform, $\omega$ the angular frequency, and $I_1^*(\omega)$ denotes the complex conjugate of $I_1(\omega)$. The same applies for $i_2$ and $I_2$ at time $t + dt$. The POC function exhibits a unique sharp peak when the signal $i_1$ is a shifted version of $i_2$. Using this property, we obtained the required displacement $\boldsymbol{u}$ in voxels:

$$\boldsymbol{u} = \arg \max_{x} (r(\boldsymbol{x}))$$

## Results and discussion

The study of cell morphology showed that T24 and J82 cells have similar values of sphericity index, significantly smaller than RT112 cells (Table 1). Moreover, the analyse of cell morphology showed that T24 and J82 cells were able to migrate using a great diversity of shapes (shape with long protrusions and elongated morphology) whereas RT112 move with a round or slightly elongated shape showing short extensions. In term of migration speed, we measured a higher value of speed for J82 as comparing to T24 and RT112 (Table 1).

<table><caption>Table 1: Sphericity index mean and instantaneous migration speed mean ± standard error of the mean</caption><thead><tr><th></th><th>Sphericity index</th><th>Migration speed (μm/h)</th></tr></thead><tbody><tr><td>RT112</td><td>0.467</td><td>9.1 ± 1.1</td></tr><tr><td>T24</td><td>0.429</td><td>14.9 ± 2.3</td></tr><tr><td>J82</td><td>0.426</td><td>21,0 ± 4.1</td></tr></tbody></table>

<footnote n="1">1. Université Grenoble Alpes, CNRS, Laboratoire Interdisciplinaire de Physique (LIPhy), France;</footnote>

<footnote n="2">2. Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, France</footnote>
Figure 2 shows an example of fiber displacement fields for T24 and J82 cells. Our results show the J82 cells produce the greatest displacement of fibers in comparison to T24 (Figure 2) and RT112 (data not shown). Moreover, the 3D time lapse of displacement field reveals that cancer cells can push and/or pull on collagen fibers to effectively deform collagen [4].

<figure><img src="image_2.png" /><figcaption>Figure 2: 3D collagen fiber displacements around one T24 cell (left) and J82 cell (right). The initial 3D cell shape is shown in grey levels. The vector length and color indicate the displacement magnitude in µm. The x, y and z grids are in µm</figcaption></figure>

To conclude, our results reveal that the spatial deformation of the environment during the 3D migration is not uniform and follows steps depending of cancer cell invasiveness.

## References

1. Iordan et al., Biorheology, 47:277-295, 2010.

2. Abidine et al., Biophys. J., 114:1165-75. 2018.

3. Fertin et al., J. Microsc., 275:172-182, 2019.

4. Laurent et al., Sci. Report, 12:7867, 2022

## Acknowledgements

We thank the Agence Nationale de la Recherche (grant # 12-BS09-020-01, TRANSMIG). C.V. and V.M.L. are members of the LabeX Tec 21 (Investissements d'Avenir: grant agreement No. ANR-11-LABX-0030).