When the researchers increased the
mitochondrial content with an inhibitor, the cancer cells responded to the
treatment.
Scientists at Karolinska Institutet,
Sweden, have linked resistance to treatment for a deadly form of kidney cancer
to low mitochondrial content in the cell. When the researchers increased the
mitochondrial content with an inhibitor, the cancer cells responded to the
treatment. Their findings, which are published in Nature Metabolism, offer hope
for more targeted cancer drugs.
“We have shown for the first time how
the formation of new mitochondria is regulated in cells that lack oxygen and
how this process is altered in cancer cells with VHL mutations,” said Associate
Professor Susanne Schlisio.
The researchers examined the protein
content of cancer cells from patients with different variants of VHL syndrome,
and how they differed from another group of individuals with a special VHL
mutation called Chuvash, a mutation involved in hypoxia-sensing disorders
without any tumour development. Those with the Chuvash VHL-mutation had normal
mitochondria in their cells, while those with VHL syndrome mutation had few.
To increase the amount of
mitochondrial content in VHL related kidney cancer cells, the researchers
treated these tumours with an inhibitor of a mitochondrial protease called
“LONP1”. The cells then became susceptible to the cancer drug sorafenib, which
they had previously resisted. In mouse studies, this combination treatment led
to reduced tumour growth.
“We hope that this new knowledge will
pave the way for more specific LONP1 protease inhibitors to treat VHL-related
clear cell kidney cancer,” concluded the study’s first author Shuijie Li. “Our
finding can be linked to all VHL syndromic cancers, such as the neuroendocrine
tumours pheochromocytoma and paraganglioma, and not just kidney cancer.”