Hunting Cancer With Killer Immune Cells

An image of a natural born killer cell. Credit: Nele Dieckmann and Nicola Lawrence, Wellcome Images

Scientists at Cornell have created ‘super natural killer’ cells, which can hunt down and destroy cancer in lymph nodes; preventing it from using the lymph system as a highway to spread across the body. 

Halting metastasis

Survival rates are high if a tumour has yet to spread and surgical removal is usually effective, with most patients making a good recovery. The problem with cancer is that it can spread. This spread, also called metastasis, produces pockets of cancer cells all across the body that become extremely difficult to both find, and destroy. This invasive process is what makes cancer so dangerous, because it attacks your body on multiple fronts. 

“We want to see lymph node metastasis become a thing of the past” 

Killer T cells encircling a cancer cell Credit: NIH

Metastasis often begins through the lymph system

The lymph, or lymphatic, system is a part of the circulatory system which filters your blood and transports the immune system. Within this network lie lymph nodes, small organs in which lymphocytes are created. Lymphocytes are a type of white blood cell required for an effective immune system. Cancer frequently uses this network, alongside the blood, to colonise new organs and tissue. 

A helping hand

In an effort to stop this, scientists at Cornell used liposomes filled with something called TRAIL (Tumor necrosis factor Related Apoptosis-Inducing Ligand). Liposomes are essentially small packages encircled by a fatty membrane similar to cells, and they can carry and release their contents into a target site. They bound these liposomes to a type of immune cell called a natural killer cell, which form part of our innate immune system. These have a range of functions from finding cancer to destroying cells infected with a virus. Attached to the searching killer cells, the TRAIL ligand is able to induce cancer cells to commit suicide.

A lymph node with metastatic adenocarcinoma Credit: Ed Uthman

“In our research, we use nanoparticles — the liposomes we have created with TRAIL protein — and attach them to natural killer cells, to create what we call ‘super natural killer cells’ and then these completely eliminate lymph node metastases in mice”

Around 29 to 37% of patients with lung, breast or colorectal cancer show signs of metastasis in lymph nodes lying underneath their initial tumour. If we could tackle this spread more effectively, many cancers would find it difficult to expand.

A weapon against cancer in the blood too

In a paper in 2014, the same team reported that using the TRAIL containing liposomes attached to white blood cells had great effect on cancer cells using the blood instead of the lymph system. 

“So, now we have technology to eliminate bloodstream metastasis — our previous work — and also lymph node metastases”

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