Prof. Josef Käs, Universität Leipzig
Invited by Prof. Joachim Rädler and Prof. Erwin Frey
The colloquium will be streamed online.
Cancer is a highly complex, multifaceted disease that accounts for nearly one in six deaths worldwide. More than 90% of cancer deaths are due to metastases — the process by which cancer cells escape from the primary tumor and seed a secondary tumor in a distant organ or tissue. Despite advances in cancer treatment, metastatic recurrences remain a significant challenge. The metastatic cascade makes mechanical changes nesessary, a problem for tumor cells on their way through the human body squeezing through dense tissue. Concepts of the Physics of Cancer provide a paradigm-shifting insight into the conditions required for cancer cell motility, as a fundamental prerequisite for metastatsis.
Tumors are a composite material of active directional objects such as individual, motile and dividing cancer cells or small and large cell groups embedded in the passive, aligned extracellular matrix (ECM). Their dynamic fits well into the framework of nematic physics, which describes highly aligned states of matter. With respect to the mechanical interplay between proliferation, migration and fibrosis we establish that the dynamics of the ECM and the cells can be quantitatively modelled by describing a tumour’s cellular constituents as active nematic blobs within a passive nematic ECM. Current biomechanical techniques require vital samples and are thus limited in their observation times. We overcome this problem with histopathological studies based on nematic physics. The static fixed histological images of large patient cohorts serve as temporal snapshots of longterm tumour progression and the nematic variables translate active cancer mechanics into features in the tumour architecture.
Two clinical trials with more than 2000 breast cancer patients in each study prove that the onset of cancer cell motility can be explained as an unjamming transition and local cancer spreading of cancer cell clusters embedded in ECM must be described as active nematic blobs in a nematic phase. We derive novel early tumor markers that improve diagnosis by 25%. Breast cancer has a long risk of relapse. We can highly reliably identify patients with a negligible risk of relapse. Any strong tumour marker is a potential target for developing novel therapeutic approaches. Low dose taxol treatment that stiffens and roundens cells disturbing the nematic nature of cancer cells, jams cancer cells and inhibits collective cell motility. This demonstrates the possibility of migrastatic therapies inhibiting metastasis.