Unlocking cell nucleus behavior may be important in fighting cancer.
The nucleus of the cell was believed to be elastic like a rubber ball. It deforms and snaps back into shape as the cell navigates through pores and between fibers inside the human body. Now, scientists from Texas A&M University and the University of Florida have discovered that the cell nucleus is more complex than previously thought.
They found that it behaved more like a liquid drop than a rubber ball. The study calls for a fresh look at how the nuclear shape becomes abnormal in diseases such as cancer.
The nucleus contains a genome that monitors the function and behavior of a cell. Misshapen nuclei are indicating diseases like cancer. It is possible for cancer cells with such an abnormal nucleus to spread throughout the body, a process known as cancer metastasis, which has the potential to be fatal.
Even now, observation of nuclear size is used to diagnose cancer. However, the cause of the abnormal nucleus remains a mystery. It may be possible to develop novel methods to treat cancer by helping cell nuclei recover their normal shape, by understanding how they are shaped abnormally.
The findings of this study are important for understanding how a protective layer around the nucleus, called the lamina, helps preserve nuclear shape. At the same time, cells crawl through the pores and along the annoying paths around the tissue fibers.
Scientists, in this study, explored nuclear behavior by placing fibroblasts in a miniature obstacle course of small, flexible columns 1/100th the width of a human hair. Creeping through this maze of obstacles, the nuclei of cells had to be squeezed between the pillars.
The scientists studied the movements using a state-of-the-art, high-resolution microscope that can capture images of the three-dimensional structures of nuclei. Imaging also revealed that the pillars made deep indentations in the nuclear surface. Yet the overall atomic shape was preserved, allowing the nucleus to pass successfully through the barriers, like a liquid droplet, as opposed to an elastic elastic rubber ball.
The study also revealed that the lack of lamin A/C, one of the regular protein components of the lamina, causes nuclei to become entangled in barriers. The finding indicates that lamin A/C assists in preserving the surface tension of “nuclear droplets”.
Dr. Tanmay Lele, Unocal Professor in the Department of Biomedical Engineering, said, “Our work points to a fundamental mechanism by which the nucleus maintains its shape and protects its genome. Our discovery also helps us understand this.” how misshapen nuclei arise in cancer and potentially re-normalize them. We are now studying the implications of the drop model for abnormal nuclear shapes commonly seen in cancer.”