Double agents: Vessels that help cancers spread can also boost immune therapies

September 13, 2017, University of Chicago Medical Center
Intratumoral lymphatic vessel (green) imaged in the microenvironment (red) of a Braf-driven primary mouse melanoma tumor. Credit: Manuel Fankhauser and Maria Broggi/EPFL

In a surprise finding, an international research team from the University of Chicago, the University of Lausanne, and the Swiss Federal Institute of Technology in Lausanne has discovered that the lymphatic vessels, often blamed for enabling cancer cells to spread from a primary location to many other sites, have a flip side.

Lymphatics can expand around and into a tumor - a process known as lymphangiogenesis. This process has long been associated with a cancer's ability to spread to new locations.

But a team led by Melody Swartz, PhD, the William B. Ogden Professor in Molecular Engineering at the University of Chicago, found that in patients being treated with checkpoint inhibitors - drugs such as ipilimumab or nivolumab that help activate an immune response against the tumor - lymphangiogenesis can strongly enhance the effects of cancer immunotherapy. It boosts the immune system's primary anti-cancer tool, T cells, enabling them to infiltrate tumors and kill cancer cells.

The study, piloted by first authors Manuel Fankhauser and Maria Broggi and published in the 13 September, 2017, issue of Science Translational Medicine, suggests that physicians may predict - with a simple blood test before starting treatment - which patients are most likely to benefit from cancer immunotherapy, at least in melanoma patients. Currently, only a minority of patients actually benefit from such therapies. Moreover, it has the potential to lead to new therapeutic strategies to make cancer immunotherapy more effective for more patients.

"Our study presents a completely unexpected role for the lymphatic system in cancer therapy," explained Swartz.

Lymphangiogenesis is driven in part by a chemical messenger, vascular endothelial growth factor-C (VEGF-C), which has long been associated with metastasis and poor patient prognosis, and can also promote immune suppression in the tumor microenvironment.

"VEGF-C was always considered bad for cancer patients," Swartz said. "We thought that blocking VEGF-C would help boost immunotherapy by removing some factors that suppress the abilities of T cells to kill tumor cells. That was our original hypothesis." But their studies in mice, followed by human data obtained from two clinical trials for melanoma patients, changed their thinking.

Melanoma tumors trigger new blood and lymph vessel growth (shown in green). Credit: M. Fankhauser et al., Science Translational Medicine (2017)

"It was exciting to get such surprising results," Swartz said. "And the translational implications are even more exciting than if our hypothesis had been correct."

In both trials, the results showed that VEGF-C levels in the blood before immunotherapy "not only predicts the magnitude and quality of immune responses raised by a cancer vaccine but also stratifies long-term patient responses to combined checkpoint blockade and further strengthens the case for investigating the use of serum VEGF-C as a predictive biomarker for immunotherapy candidates," the authors wrote.

"Before the trials began, we took blood samples," Swartz said. "We measured dozens of factors, but nothing else correlated, not VEGF-A, VEGF-D or other growth factors, only VEGF-C."

"The difference was really striking," Swartz said. Almost all of the patients with higher than average VEGF-C levels in their blood responded to immunotherapy. This not only resulted in eradication of the primary tumors, it also encouraged T cell infiltration into metastatic tumors and resulted in long-term protection.

This could become a useful biomarker, Swartz suggested. "It's easy to measure from a blood sample. And it can predict who is likely to respond. If VEGF-C is low, immunotherapy is much less likely to be effective."

The authors noted several limitations, including the potential effects of VEGF-C on other immune cell subsets, the contributions of other cytokines and competition with other T cells for nutrients. Despite those limitations, this study "brings into focus a more comprehensive understanding of the immune microenvironment," Swartz said.

"We now appreciate the numerous mechanisms of immunosuppression that a T cell-inflamed tumor develops to survive, including lymphangiogenesis," the authors conclude. "But when the scales are tipped toward activating factors dominating over suppressive ones, as is the case with immunotherapy, these T cells become robust participants in antitumor immunity."

Explore further: Modulating T-cell metabolism uncovers new technology for enhancing immunotherapy

More information: Fankhauser el al., "Tumor lymphangiogenesis promotes T cell infiltration and potentiates immunotherapy in melanoma," Science Translational Medicine (2017). stm.sciencemag.org/lookup/doi/ … scitranslmed.aal4712

Related Stories

Modulating T-cell metabolism uncovers new technology for enhancing immunotherapy

September 11, 2017
T lymphocytes found in tumors and implicated in killing tumor cells cope with the shortage of oxygen and nutrients in the tumor microenvironment by using fat as the main source of energy. Promoting a switch from glucose to ...

Immunotherapy combination safe and 62 percent effective in metastatic melanoma patients

September 7, 2017
Immunotherapy is a promising approach in the treatment of metastatic melanoma, an aggressive and deadly form of skin cancer; but for most patients, immunotherapy drugs so far have failed to live up to their promise and provide ...

Cancer immunotherapy may get a boost by disabling specific T cells

September 7, 2017
Cancer immunotherapy drugs only work for a minority of patients, but a generic drug now used to increase blood flow may be able to improve those odds, a study by Columbia University Medical Center (CUMC) researchers suggests.

Targeting blood vessels to improve cancer immunotherapy

April 12, 2017
EPFL scientists have improved the efficacy of cancer immunotherapy by blocking two proteins that regulate the growth of tumor blood vessels.

New study identifies essential genes for cancer immunotherapy

August 7, 2017
A new study identifies genes that are necessary in cancer cells for immunotherapy to work, addressing the problem of why some tumors don't respond to immunotherapy or respond initially but then stop as tumor cells develop ...

Scientists find the key to improved cancer immunotherapy

July 18, 2017
Researchers at the Centro Nacional de Investigaciones Cardiovasculares Carlos III (F.S.P.) have investigated how different subtypes of essential immune-response cells called CD8+ T lymphocytes cooperate to mount a stronger ...

Recommended for you

Research team discovers drug compound that stops cancer cells from spreading

June 22, 2018
Fighting cancer means killing cancer cells. However, oncologists know that it's also important to halt the movement of cancer cells before they spread throughout the body. New research, published today in the journal Nature ...

Dying cancer cells make remaining glioblastoma cells more aggressive and therapy-resistant

June 21, 2018
A surprising form of cell-to-cell communication in glioblastoma promotes global changes in recipient cells, including aggressiveness, motility, and resistance to radiation or chemotherapy.

Existing treatment could be used for common 'untreatable' form of lung cancer

June 21, 2018
A cancer treatment already approved for use in certain types of cancer has been found to block cell growth in a common form of lung cancer for which there is currently no specific treatment available.

Novel therapy makes oxidative stress deadly to cancer

June 21, 2018
Oxidative stress can help tumors thrive, but one way novel cancer treatments work is by pushing levels to the point where it instead helps them die, scientists report.

Higher body fat linked to lower breast cancer risk in younger women

June 21, 2018
While obesity has been shown to increase breast cancer risk in postmenopausal women, a large-scale study co-led by a University of North Carolina Lineberger Comprehensive Cancer Center researcher found the opposite is true ...

Researchers uncover new target to stop cancer growth

June 21, 2018
Researchers at the University of Wisconsin-Madison have discovered that a protein called Munc13-4 helps cancer cells secrete large numbers of exosomes—tiny, membrane-bound packages containing proteins and RNAs that stimulate ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.