9th Annual Symposium
Physics of Cancer
Leipzig, Germany
September 24-26, 2018
Invited Talk
Probing the physiology of physical transport inside cells and developing tissues
Moritz Kreysing
Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Center of Systems Biology, Dresden
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Throughout the last decades, access to genetic perturbations, fluorescent labels and modern microscopy advanced our molecular understanding of cell-biological processes tremendously.
The spatio-temporal organization of cells, developing embryos and cancers that we observe under these microscopes is widely believed to also depend on physical processes, such as diffusion, motor-driven intracellular flows as well as cell migration. Thus far, however, it often remains a challenge to experimentally test the physiology of these physical transport processes, which is due to the lack of suitable perturbation methods.

Here, we exploit thermoviscous expansion phenomena to optically induce hydrodynamic flow in single cells and developing embryos. By controlling such flows inside the cytoplasm of the C. elegans zygote, we reveal the causal implications of intracellular flows during PAR polarization. Specifically, we show that i) hydrodynamic flows inside the cytoplasm localize PAR-2 proteins at the posterior membrane and drive cell polarization. ii) Induced cortical flows transporte membrane-bound PAR molecules and rotate the membrane polarization, leading to iii) the down-stream phenotype of an inverted body axis.

Furthermore, we utilize flow perturbations for probe-free active micro-rheology of the cytoplasm. From here, I discuss challenges and opportunities how to leverage cancer research by next generation, interactive imaging. In particular we discuss how optically generated extracellular flows could compensate for a lack of vascularization in tumor spheroids, and how to overcome the problem of tissue-induced light scattering, which currently precludes live imaging deep inside cancers.
[1]Mittasch et al., Nat Cell Biol 20 (2018)
[2]Kruse, Chiaruttini, and Roux, Nat Cell Biol 20 (2018)
[3]Weigert et al., PLOS Comp Bio 14 (2018)
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