The study explores how cancer can release molecules in the bloodstream, that modify the liver,
further disrupting the detoxification processes.
Researchers at Weill Cornell Medicine found that cancer often releases molecules into the
bloodstream that pathologically modify the liver, sending it into an inflammatory state, causing fat
accumulation, and disrupting its typical detoxification processes. This finding sheds light on one
of cancer's sneakier survival strategies and raises the prospect of fresh diagnostics and therapeutics
for identifying and reversing this process.
In the study, which was published in Nature, the researchers discovered that extracellular vesicles
and particles (EVPs) containing fatty acids secreted by a wide range of tumour types that are
developing outside the liver can remotely reprogram the liver to a condition approximating fatty
liver disease. The livers of cancer patients and animal models of the disease both included signs
of this mechanism, according to the researchers.
"Our findings show that tumors can lead to significant systemic complications including liver
disease, but also suggest that these complications can be addressed with future treatments," said
study co-senior author Dr. David Lyden, the Stavros S. Niarchos Professor in Pediatric Cardiology
and a professor of pediatrics and of cell and developmental biology at Weill Cornell Medicine.
For the past two decades, Dr. Lyden, who is also a member of the Gale and Ira Drukier Institute
for Children's Health and the Sandra and Edward Meyer Cancer Center atWeill Cornell Medicine,
and his research group have been studying the systemic effects of cancers. These effects reflect
specific strategies cancers use to secure their survival and speed their progression. In their work
published in 2015, for example, the team discovered that pancreatic cancers secrete molecules
encapsulated in extracellular vesicles, that travel through the bloodstream, are taken up by the
liver, and prepare the organ to support the outgrowth of new, metastatic tumors.
In the new study, the researchers uncovered a different set of liver changes caused by distant cancer
cells which they observed in animal models of bone, skin and breast cancer that metastasize to
other organs but not to the liver. The study's key finding is that these tumors induce accumulation
of fat molecules in liver cells, consequently reprogramming the liver in a way that resembles the
obesity- and alcohol-related condition known as fatty liver disease.
The team also observed that reprogrammed livers have high levels of inflammation, marked by
elevated level of tumor necrosis factor-a (TNF-a), and low levels of drug-metabolizing enzymes
called cytochrome P450, which break down potentially toxic molecules, including many drug
molecules. The observed reduction in cytochrome P450 levels could explain why cancer patients
often become less tolerant of chemotherapy and other drugs as their illness progresses.
The researchers traced this liver reprogramming to EVPs that are released by the distant tumors
and carry fatty acids, especially palmitic acid.When taken up by liver-resident immune cells called
Kupffer cells, the fatty acid cargo triggers the production TNF-a, which consequently drives fatty
liver formation.
Although the researchers principally used animal models of cancers in the study, they observed
similar changes in the livers of newly diagnosed pancreatic cancer patients who later developed
non-liver metastases.
"One of our more striking observations was that this EVP-induced fatty liver condition did not cooccur
with liver metastases, suggesting that causing fatty liver and preparing the liver for
metastasis are distinct strategies that cancers use to manipulate liver function," said co-first author
Dr. Gang Wang, a postdoctoral associate in the Lyden laboratory. Dr. Jianlong Li, a scientific
collaborator in the Lyden laboratory, is also a co-first author of the study.
The scientists suspect that the fatty liver condition benefits cancers in part by turning the liver into
a lipid-based source of energy to fuel cancer growth.
"We see in liver cells not only an abnormal accumulation of fat but also a shift away from the
normal processing of lipids, so that the lipids that are being produced are more advantageous to
the cancer," said co-senior author Dr. Robert Schwartz, associate professor of medicine in the
Division of Gastroenterology and Hepatology and a member of the Meyer Cancer Center at Weill
Cornell Medicine and a hepatologist at NewYork-Presbyterian/Weill Cornell Medical Center.
That may not be the only benefit that cancers derive from this liver alteration. "There are also
crucial molecules involved in immune cell function, but their production is altered in these fatty
livers, hinting that this condition may also weakens anti-tumor immunity," said co-senior author
Dr. Haiying Zhang, assistant professor of cell and developmental biology in pediatrics at Weill
Cornell Medicine.
The researchers were able to mitigate these systemic effects of tumors on the livers by
implementing strategies such as blocking tumor-EVP release, inhibiting the packaging of palmitic
acid into tumor EVPs, suppressing TNF-a activity, or eliminating Kupffer cells in the experimental
animal models. The researchers are further investigating the potential of implementing these
strategies in human patients to block these remote effects of tumors on the liver, and exploring the
possibility of utilizing the detection of palmitic acid in tumor EVPs circulating in the blood as a
potential warning sign of advanced cancer.
This story has been published from a wire agency feed without modifications to the text. Only the
headline has been changed.
https://www.hindustantimes.com/lifestyle/health/how-cancers-in-distant-organs-change-liverfunction-
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