Professor Mike Berridge and his team from the Wellington based-Malaghan Institute of Medical research have for the first time ever shown that mitochondrial DNA movement occurs between cells in an animal tumour.
Mitochondria also known as the powerhouse of a cell, produces energy for the activities of cell and contains its own DNA called as mitochondrial DNA (mtDNA) which is distinct from the nuclear DNA which specifies the sex, traits of an individual. Since mitochondria plays a crucial role in the cell, the team hypothesized that removal of mtDNA in cancerous cells would cause tumours to stop growing.
In the mouse models of breast cancer in which mtDNA was removed, the cells did not grow immediately but within a month the cells started dividing again and tumours reappeared, which prompted the question: did the cell learn how to grow without mtDNA? This lead to extensive molecular, biochemical and protein analysis which showed that, the mitochondria deficient cell infact, received mtDNA from the surrounding normal(non-cancerous) cells and continued proliferating into tumors. This is the first time, scientists have proved transfer of mitochondrial DNA between cells in an animal model. Their paper was published today in the leading biological journal Cell Metabolism.
As much as 200 different diseases can be attributed to defects in mitochondrial DNA, hence this work could also usher in a new field where disease-causing, defective mtDNA could be replaced with custom synthetic DNA.
In conclusion, Prof Berridge says, “Our findings overturn the dogma that genes of higher organisms are usually constrained within cells except during reproduction. It may be that mitochondrial gene transfer between different cells is actually quite a common biological occurrence.”
The original paper can be accessed here.