Immune cells determine the growth rate of certain tumors: study – Xinhua

CHICAGO, May 30 (Xinhua) – In examining brain tumors in mice, researchers at the Washington University School of Medicine in St. Louis have discovered that immune cells that should defend the body against diseases could sometimes be prompted to bring help and comfort to tumor cells instead.

The speed with which a tumor develops does not depend solely on the speed with which the cancer cells can divide. The researchers found that the more tumors that can recruit immune cells, the faster the tumor grows.

To better understand why some tumors grow faster than others, the researchers created five strains of mice with different genetic changes in the NF1 gene and elsewhere in the mouse genome.

The five strains varied greatly in development and tumor growth. Mice belonging to three of the strains developed tumors from the age of about 3 months, with tumors of a mouse strain growing particularly rapidly. Members of the fourth strain did not develop tumors until about 6 months of age, and only a quarter of the fifth strain mice developed brain tumors on the optic nerve.

When the researchers isolated the tumor cells from the mice and grew them in a dish, they found a small difference in tumor cell growth. The growth rates and other properties of the cancer cells were very similar, regardless of the mutation of the tumor cells.

The correlation with overall tumor proliferation in mice was the presence of two types of immune cells, microglial cells and T cells, in tumors. The researchers found that the tumor cells themselves released proteins from the immune system that attracted immune cells to the tumor.

"Cells that should be part of the brain's defense against tumors are now part of the process of making and growing a tumor," said David H. Gutmann, senior author, professor of neurology and director of the Center. of neurofibromatosis from the University of Washington.

Researchers are now trying to leverage this relationship between tumor cells and immune system cells to find new ways to treat brain tumors in people with NF1.

One strategy is to slow down tumor growth by preventing microglia or T cells from providing support to cancer cells. And a more ambitious strategy is to reprogram T cells to no longer promote the growth of tumor cells.

The results were published Wednesday in the journal Neuro-Oncology.