WASHINGTON, Jan 1:
Scientists have mapped the effects of biological machinery that drives a deadly brain cancer called diffuse intrinsic pontine glioma (DIPG).
A group at St Jude Children’s Research Hospital in the US made a genetically engineered mouse that offers approaches to additionally see such brain cancers, and a laboratory model for growing progressively powerful medications.
DIPGs are serious brainstem tumors that strike hundreds of children a year in the US, as per the study published in the journal Cancer Cell.
Current medications of radiation and chemotherapy are to a great extent insufficient, and less than 10 percent of youngsters with the tumors survive more than two years.
Although many cancers arise from mutations in the genes that straightforwardly drive abnormal cell proliferation or survival, others, for example, DIPGs emerge from irregularities in the cell’s “epigenetic” apparatus for managing gene activation, or expression.
The analysts discovered that a key mutation called H3 K27M in the epigenetic machinery happens in by far most of DIPG cases.
“It wasn’t clear exactly how that translated into changes in regulation of gene expression,” said Jinghui Zhang from St Jude Children’s Research Hospital.
“And it was really completely unclear why this particular mutation was oncogenic in this disease,” Zhang said.
The H3 K27M mutation arises in a gene that codes for an atom called a histone. Histones work as “smart packaging” for genes — compacting DNA to fit into the restricted space of the cell’s nucleus and influencing whether the genes are activated or kept inactive.
“One of the biggest mysteries is why this mutation is so selectively seen in brainstem gliomas and other midline gliomas in kids when the H3 histone is important in packaging the DNA in every cell in the body,” said Suzanne Baker from St Jude Children’s Research Hospital.
To analyse the mutation’s effects, the researchers genetically engineered a strain of mice so that scientists could specifically switch on the mutation in a similar kind brain cell that offers ascend to the human cancer. They engineered the mice so that the mutant gene was expressed at the same levels as in human DIPGs.
The mouse study revealed critical details of how the mutation causes DIPG. The mutation triggers immature cells called neural stem cells to increase their stem cell activity during a specific time in brain development. The finding helps explain why DIPGs occur in children, whose brains are still developing, Baker said. (AGENCIES)