Researchers uncover a survival mechanism in cancer cells

November 22, 2016

An international study led by scientists from the Crick Institute in London and the Hebrew University of Jerusalem revealed a survival mechanism in cancer cells that allows the disease to erupt again even after aggressive treatment. In a paper published in Science (LINK) the researchers describe the mechanism by which cancer tumor cells become cancer stem cells that can sustain long-term growth.

When cancer develops, the generated cells are not uniform in their biological properties and contribute differently to tumor development. Only a small portion of cancer cells can form new tumors or metastases, and these are called "cancer stem cells". This disparity between tumor cells poses major challenges in understanding the nature of the tumor, its sensitivity to drugs, and planning an effective treatment that will eliminate all tumor cells.

"Many chemotherapy drugs leave a small amount of cancer stem cells that cause a renewed outbreak of the disease after a few years. It is therefore important to identify cancer stem cells in tumors and characterize the differences between the different tumor cells as the basis for detecting weak spots in the course of the development of the disease," explained Prof. Eran Meshorer, head of the Laboratory for stem cells and epigenetics in the Institute of Life Sciences and a member of the Edmond and Lily Safra Center for Brain Sciences (ELSC) of The Hebrew University of Jerusalem.

Cancer stem cells are not limited to the tumor itself and they are able to engage again in healthy environment and stimulate the disease. To study the characteristics of those unique cells, Prof. Meshorer and doctoral student Alva Biran from the Hebrew University teamed up with Dr. Paula Scaffidi and Christina Morales Torres from The Crick Institute in London. The international research team also included Dr. Ayelet Hashahar Cohen of the Hebrew University, Dr. Rotem Ben-Hamo and Professor Sol Efroni from Bar-Ilan University, and Dr. Tom Misteli from the National Cancer Institute, NIH.

The research team found that in a number of cancer types, those cancer stem cells lose one of their DNA packaging proteins - H1.0. By binding to DNA, H1.0 silences the expression of the genes it binds to.

"We found that the disappearance of H1.0 is crucial for the cancer cells to remain immortal. To understand the mechanism of action, we mapped its interaction with DNA and found that it binds to the genes' regulatory regions. When H1.0 levels go down, the genes to which it binds can be activated. These genes, it turns out, are the ones which provide the cancer cell with its immortal potential," explained Prof. Meshorer.

The study is based on epigenetics - a scientific field that investigates gene expression in DNA by switching genes on and off. In order to identify the cancer stem cells from other cells in the tumor, the research team studied epigenetic mechanisms that distinguish between the least-sorted cells, with endless division properties and a potential to create growth, and the more sorted cells which lack this ability.

The results showed an inverse relation between H1.0 and the division of cancer cells: "As the H1.0 levels fall, the greater the potential of uncontrolled division of cells. In contrast, high levels of the protein prevent this process. We found that the disappearance of protein H1.0 is characteristic of cancer stem cells and it is necessary to maintain the ability of partition and the potential for growth creation."

The discovery could open the door for medical intervention in cancer stem cells aimed at the restoration of high levels of H1.0 in all cancer cells and by that blocking the differentiation of cancer cells. While further research is needed to understand the effectiveness of H1.0 protein in preventing the spread of cancer growth, this research advances significantly the study of the mechanisms of cancer stem cells and the relatively new epigenetic approach to cancer research
-end-


The Hebrew University of Jerusalem

Related Stem Cells Articles from Brightsurf:

SUTD researchers create heart cells from stem cells using 3D printing
SUTD researchers 3D printed a micro-scaled physical device to demonstrate a new level of control in the directed differentiation of stem cells, enhancing the production of cardiomyocytes.

More selective elimination of leukemia stem cells and blood stem cells
Hematopoietic stem cells from a healthy donor can help patients suffering from acute leukemia.

Computer simulations visualize how DNA is recognized to convert cells into stem cells
Researchers of the Hubrecht Institute (KNAW - The Netherlands) and the Max Planck Institute in Münster (Germany) have revealed how an essential protein helps to activate genomic DNA during the conversion of regular adult human cells into stem cells.

First events in stem cells becoming specialized cells needed for organ development
Cell biologists at the University of Toronto shed light on the very first step stem cells go through to turn into the specialized cells that make up organs.

Surprising research result: All immature cells can develop into stem cells
New sensational study conducted at the University of Copenhagen disproves traditional knowledge of stem cell development.

The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.

Healthy blood stem cells have as many DNA mutations as leukemic cells
Researchers from the Princess Máxima Center for Pediatric Oncology have shown that the number of mutations in healthy and leukemic blood stem cells does not differ.

New method grows brain cells from stem cells quickly and efficiently
Researchers at Lund University in Sweden have developed a faster method to generate functional brain cells, called astrocytes, from embryonic stem cells.

NUS researchers confine mature cells to turn them into stem cells
Recent research led by Professor G.V. Shivashankar of the Mechanobiology Institute at the National University of Singapore and the FIRC Institute of Molecular Oncology in Italy, has revealed that mature cells can be reprogrammed into re-deployable stem cells without direct genetic modification -- by confining them to a defined geometric space for an extended period of time.

Researchers develop a new method for turning skin cells into pluripotent stem cells
Researchers at the University of Helsinki, Finland, and Karolinska Institutet, Sweden, have for the first time succeeded in converting human skin cells into pluripotent stem cells by activating the cell's own genes.

Read More: Stem Cells News and Stem Cells Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.