KCC Research: Cancer Cells Accelerate Aging & Inflammation in Body to Drive Tumor Growth

Researchers at the Kimmel Cancer Center at Jefferson have shed new light on the longstanding conundrum about what makes a tumor grow—and how to make it stop.  Interestingly, cancer cells accelerate the aging of nearby connective tissue cells to cause inflammation, which ultimately provides “fuel” for the tumor to grow and even metastasize.

Michael Lisanti, MD, PhD

This revealing symbiotic process, which is similar to how muscle and brain cells communicate with the body, could prove useful for developing new drugs to prevent and treat cancers.  In this simple model, our bodies provide nourishment for the cancer cells, via chronic inflammation.

“People think that inflammation drives cancer, but they never understood the mechanism,” said Michael P. Lisanti, M.D., Ph.D., Professor and Chair of Stem Cell Biology & Regenerative Medicine at Jefferson Medical College of Thomas Jefferson University and a member of the Kimmel Cancer Center. “What we found is that cancer cells are accelerating aging and inflammation, which is making high-energy nutrients to feed cancer cells.”

In normal aging, DNA is damaged and the body begins to deteriorate because of oxidative stress. “We are all slowly rusting, like the Tin-man in the Wizard of Oz,” Dr. Lisanti said. “And there is a very similar process going on in the tumor’s local environment.”  Interestingly, cancer cells induce “oxidative stress,” the rusting process, in normal connective tissue, in order to extract vital nutrients.

Dr. Lisanti and his team previously discovered that cancer cells induce this type of stress response (autophagy) in nearby cells, to feed themselves and grow. However, the mechanism by which the cancer cells induce this stress and, more importantly, the relationship between the connective tissue and how this “energy” is transferred was unclear.

“Nobody fully understands the link between aging and cancer,” said Dr. Lisanti, who used pre-clinical models, as well as tumors from breast cancer patients, to study these mechanisms.  “What we see now is that as you age, your whole body becomes more sensitive to this parasitic cancer mechanism, and the cancer cells selectively accelerate the aging process via inflammation in the connective tissue.”

This helps explain why cancers exist in people of all ages, but susceptibility increases as you age.  If aggressive enough, cancer cells can induce accelerated aging in the tumor, regardless of age, to speed up the process.

The researchers’ findings were published in the June 1 issue of Cell Cycle in three separate papers.

One paper analyzes the gene profiles of the laser-captured connective tissue, associated with lethal tumors, in human breast cancer patients.  In this paper, lethal cancers show the same gene expression pattern associated with normal aging, as well as Alzheimer’s disease.  In fact, these aging and Alzheimer’s disease signatures can identify which breast cancer patients will undergo metastasis. The researchers find that oxidative stress is a common “driver” for both dementia and cancer cell spreading.

In another study, the researchers explain that cancer cells initiate a “lactate shuttle” to move lactate—the “food”—from the connective tissue to the cancer cells. There’s a transporter that is “spilling” lactate from the connective tissue and a transporter that then “gobbles” it up in the cancer cells.”

The implication is that the fibroblasts in the connective tissue are feeding cancer cells directly via pumps, called MCT1 and MCT4, or mono-carboxylate transporters.  The researchers see that lactate is like “candy” for cancer cells.  And cancer cells are addicted to this supply of “candy.”

“We’ve essentially shown for the first time that there is lactate shuttle in human tumors,” said Dr. Lisanti. “It was first discovered nearly 100 years ago in muscles, 15 years ago in the brain, and now we’ve shown this shuttle also exists in human tumors.”

It’s all the same mechanism, where one cell type literally “feeds” the other.  The cancer cells are the “Queen Bees,” and the connective tissue cells are the “Worker Bees.” In this analogy, the “Queen Bees” use aging and inflammation as the signal to tell the “Worker Bees” to make more food.

Researchers also identified MCT4 as a biomarker for oxidative stress in cancer-associated fibroblasts, and inhibiting it could be a powerful new anti-cancer therapy.

“If lethal cancer is a disease of “accelerated aging” in the tumor’s connective tissue, then cancer patients may benefit from therapy with strong antioxidants and anti-inflammatory drugs,” said Dr. Lisanti. “Antioxidant therapy will “cut off the fuel supply” for cancer cells.”  Antioxidants also have a natural anti-inflammatory action.



Jefferson Researchers Unlock Key to Personalized Cancer Medicine Using Tumor Metabolism

Identifying gene mutations in cancer patients to predict clinical outcome has been the cornerstone of cancer research for nearly three decades, but now researchers at the Kimmel Cancer Center at Jefferson have invented a new approach that instead links cancer cell metabolism with poor clinical outcome. This approach can now be applied to virtually any type of human cancer cell.

Michael P. Lisanti, M.D., Ph.D., Professor and Chair of Stem Cell Biology & Regenerative Medicine at Jefferson Medical College of Thomas Jefferson University, Kimmel Cancer Center at Jefferson

The researchers demonstrate that recurrence, metastasis, and poor clinical outcome in breast cancer patients can be identified by simply gene profiling cancer cells that are using ketones and lactate as a food supply.

These findings are reported in the April 15th online issue of Cell Cycle. The investigators are calling this new approach to personalized cancer medicine “Metabolo-Genomics.”

High-energy metabolites have long been suspected to “fuel” aggressive tumor cell behavior. The researchers used this premise to generate a gene expression signature from genetically identical cancer cells, but one cell group was fed a diet of high-energy metabolites. These lactate- and ketone-induced “gene signatures” then predicted recurrence, metastasis, and poor survival.

So, it appears that what cancer cells are eating determines clinical outcome, not necessarily new gene mutations.

Michael P. Lisanti, M.D., Ph.D., Professor and Chair of Stem Cell Biology & Regenerative Medicine at Jefferson Medical College of Thomas Jefferson University and a member of the Kimmel Cancer Center at Jefferson, together with other researchers,  found that treatment of human breast cancer cells with high-energy metabolites increases the expression of genes associated with normal stem cells,  including genes upregulated in embryonic and neural stem cells.

What’s more, lactate and ketones were found to promote the growth of normal stem cells, which has critical applications for stem cell transplantation and for a host of different human diseases.  It appears that these metabolites increase “stemness” in cancer cells, which drives poorer outcomes.

“Tumors that are using the body’s own nutrients (lactate and ketones) as “fuel” have a poorer outcome for patient survival, a behavior that now can be used to predict if a patient is at a high-risk for recurrence or metastasis,” Dr. Lisanti said. “This is getting to the heart of personalized cancer medicine. Now, we have identified a panel of biomarkers that directly links cancer metabolism with targeted cancer therapy.”

These findings suggest, according to the authors, that high-risk cancer patients (those whose cancer cells use high-energy metabolites) can be treated with new therapeutics that target oxidative mitochondrial metabolism, such as the antioxidant metformin, a drug that is also used to treat diabetes.

“Knowing the gene signatures of patients whose cancer cells are “eating” these metabolites for fuel is a pivotal piece of new information that we can use to diagnose and treat cancer patients,” said Martinez-Outschoorn, M.D., of the department of Medical Oncology at Thomas Jefferson University, and the lead author of the paper. “It’s not just that we know those patients will have poor survival; we know that those patients are using mitochondrial metabolism, which is the type of energy metabolism that we should be targeting with new anti-cancer drugs.”

The researchers propose that this new approach to diagnosis and subsequent treatment be called “Metabolo-Genomics” since it incorporates both cell metabolism and gene transcriptional profiling. This strategy could now be used to direct which patients receive a particular “tailored” anti-metabolic therapy.

Genetic markers, like expression of the mutationally activated HER2 gene, provide biomarkers that can be used to identify breast cancer patients at high-risk for recurrence or metastasis, and to modify their subsequent treatment with targeted therapies (i.e., herceptin, a drug used in aggressive breast cancers).  But with “Metabolo-Genomics,” it is now about using “global” cancer cell metabolism for these predictions.

“Just by feeding cancer cells a particular energy-rich diet, it changes their character, without introducing mutations or altering their genetic profile,” Dr. Lisanti said.  “We’ve only fed them high energy nutrients that help them to use their mitochondria, and this changes their transcriptional profile.  It’s a new biomarker for “lethal” cancers that we can now treat with the right drugs, such as the antioxidant metformin.

Dr. Lisanti and his colleagues believe that tumor metabolism is the new big picture for understanding how cancers undergo recurrence and metastasis.