Japanese scientists successfully used a new cell culture platform to observe never-before-seen behaviors of live cancer cells under the microscope, leading to explanations of long-known cancer characteristics.
Sapporo/Japan — The easy-to-produce platform developed by Hokkaido University researchers offers cancer cells micro-scale attachment sites that elicit never-before-seen behaviors highly relevant to cancer’s clinical properties. The observation of these behaviors shed light on the mechanisms behind well-known properties of pancreatic cancer, one of the most lethal malignant tumors, and may lead to the identification of new treatment targets.
Assistant Professor Yukiko Miyatake explained that cancer studies so far either use cell cultures in which cancer cells wouldn't necessarily behave naturally, or tissue samples that wouldn't allow live observation. So there was a big gap in the knowledge of how cancer cells actually behave, he said. To close this gap, the scientist who led the study and focuses on cancer development mechanisms, teamed up with Associate Professor Kaori Kuribayashi-Shigetomi who specializes on micro-nano-scale bio-engineering.
Together they created a new cell culture substrate from a coated glass slide with etched islands of 30 µm diameter. For healthy cells, this is just enough space for one or two to attach. But when the researchers seeded them with pancreatic cancer cells (although they also tried other cancer cells with similar results) and incubated them overnight, the cells self-organized into micro-tumors that could move in a concerted way, as if it were one organism. Precursors to this turned out to be papillary structures that accommodate 4 or more cells by cell-in-cell invasion. This process, called entosis, is so far known only as a step in cell degradation. Here, the incorporated cells remained alive and, to their surprise, the incorporation was reversible.
When they treated the micro-tumors with the widely used anti-cancer agent Nocodazole, the micro-tumor disintegrated, but the now-detached cells survived. Moreover, the researchers observed the micro-tumors “fishing” for surrounding dead cells and ingesting them, in the process releasing chemical markers typical for dead cells. These markers ended up on the cancer cells’ surfaces, presumably masking them and enabling them to evade the immune system’s killer cells.
Striving to reduce the suffering cancer causes, Miyatake hopes this easy and low-cost technique will find widespread adoption. She is convinced that if the discoveries made during these first observations are physiologically or pathologically relevant phenomena, many more new hints may be gleaned for the development of more effective cancer treatment approaches.
Original article: Miyatake Y. et al., Visualising the dynamics of live pancreatic microtumours self-organised through cell-in-cell invasion, Scientific Reports, September 19, 2018. DOI: 10.1038/s41598-018-32122-w