Cancer Vaccine Successfully Prevents Tumor Growth By Targeting Blood Vessels

New vaccine treats cancer by attacking the blood vessels, not the tumor. Photo courtesy of Shutterstock

Battling cancer is essentially fighting a war for your life so it would make sense that researchers are developing a cancer treatment that reflects a military operation. Rather than deploying a full-on assault on the disease, this new treatment attacks the cancer’s supplies, leading to a slow, yet certain defeat. The vaccine ultimately kills the cancerous tumors by attacking the blood vessels that keep them alive.

Cut The Supply Line

A group of researchers from the Abramson Cancer Center and the Perelman School of Medicine at the University of Pennsylvania figured out how to develop a unique DNA vaccine that kills cancerous tumors but by attacking their blood vessels, thus cutting them off from their nutrients. Based on their study, by targeting the blood vessels necessary to keep the tumor alive, the vaccine decreases tumor vascularization, increases hypoxia of the tumor, and reduces the tumor’s growth. “Our results confirm that we were directly targeting the tumor vasculature and also indirectly killing tumor cells through epitope spreading,” Andrea Facciabene, a researcher on the study, explained in a recent press release.

The DNA Vaccine

The vaccine, known as TEM1-TT, was created by fusing DNA with pieces of the tetanus toxoid. It specifically targets TEM1 (tumor endothelial marker 1), a protein that is abundant in tumors and scarce in normal tissue. In the clinical trials, three mice with three different types of cancer (breast, colon, and cervical) were injected with the vaccine. In all cases, the tumor formation was delayed, and even prevented. The vaccine is also able to indirectly create an immune response to the tumor. In a process called epitope spreading, the vaccine prompted specific T cells to fight other tumor cells, creating a therapeutic effect.

“This is a different approach which should heighten optimism for cancer vaccines in general. Moreover, based on what we’ve seen in our mouse studies, this vaccine doesn’t seem to show any significant side effects,” Facciabene added. Previous studies targeted the formation of the new blood vessels. This approach was found to often interfere with normal process involved with wound healing and development.

Next Step, Human Trials

Another benefit of the vaccine is that it generates a memory immune response. According to Facciabene, this is ideal for high risk populations. “Using this vaccine simultaneously with radiation may eventually have a double synergy,” Facciabene concluded, explaining that radiation would aid in the epitope spreading facilitated by TEM1-TT. The vaccine will soon move on to Phase 1 human clinical trials.

The idea of using vaccines to combat cancer is not a new idea. The HPV vaccine, Gardisil, effectively works against the cervical cancer-causing virus, even in those with HIV. Another cancer vaccine, CDX-1401, had positive results in its phase 1 trial. The vaccine was able to demonstrate robust antibody and T cell responses in patients with very advanced cancers. Its results suggest that it will help patients have better outcome when used concurrently with other cancer treatments.

Source: Facciponte J, Ugel S, De Sanctis F, et al. Tumor endothelial marker 1-specific DNA vaccination targets tumor vasculature. The Journal of Clinical Investigation. 2014

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