Mechanics working in the cellular world
They present varying levels of hardness... Who? Cells! And beyond technological performance to determine their rigidity, it is also an indicator of their tumorous status.
Jean-Baptiste Manneville, head of CNRS research at Institut Curie, is exploring the visco-elasticity of cells. Are some cells “softer” than others? To answer this very important question for bio-physicists, and as he would later find for cancer biologists, he first developed a cellular micro-manipulation system. This involves introducing a 2-µm diameter ball into the cell then holding it in place using optical pincers. By then moving the cell, he calculates how long the ball takes to return to its initial position.
After testing this system on normal cell lines, the researcher and the post-doc involved in the project, Kaplana Mandal, wanted to find out what happened in cell lines from a breast cancer. “Some data were already there,” the researcher tells us. “We knew that tumorous cells were easier to deform than others, whereas if we consider the tumour overall, it is more rigid. What surprised us was the difference in rigidity between the types of cells that we studied.” Because the system developed in the laboratory Molecular Mechanisms of Intracellular Transport (CNRS/UPMC/Institut Curie) directed by Bruno Goud, has the great advantage of being able to quantify the phenomena observed and their variations inside the cell using binding micropatterns.
Thinking about the “softness” of cells...
The researcher is now focusing on mapping the rigidity of several cell families, both healthy and tumorous. His aim is to fine-tune his system to make it a diagnostic tool to provide information in addition to that already gathered by other techniques. In parallel, he is also seeking to find out why tumorous cells are “soft”. The cell cytoskeleton, formed by actin, microtubules and the filaments between them, and the related molecular motors are very probably a factor in this variability. For example, the more energy is supplied to a cell in the form of ATP, the less rigid it becomes. Jean-Baptiste Manneville can count on the following collaborations to pursue the study of these aspects:
- at Institut Curie since many researchers are very familiar with these phenomena
- outside the Institut, in particular with Atef Asnacios from the Laboratoire Matière et Systèmes Complexes (CNRS/Université Paris Diderot) which has developed a microplate technique to measure rigidity on the scale of the entire cell.
There are many mechanisms and links between intracellular mechanics and cellular metabolism to be pursued.
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Mapping intracellular mechanics on micropatterned substrates
Kalpana Mandal, Atef Asnacios, Bruno Goud, Jean-Baptiste Manneville