Natural Killers Fight Childhood Cancer! [VIDEO]

By Dean Lee, M.D., Ph.D., St. Baldrick’s Scholar

This March, I had my head shaved by 2012 Ambassador Emily at Brian O’Neill’s Irish Pub in Houston, Texas. This was my second year as a shavee and team captain of the team Natural Killers, named for the key element in my childhood cancer research.

Natural killer cells, or NK cells, are a part of the body’s innate immune system. They have a natural ability to kill a lot of different kinds of tumor cells. Our lab’s focus is to develop ways that we can grow large numbers of these cells to be used as therapy and to modify how they work so that they can target cancers even better. In terms of clinical application, these cancers include acute myeloid leukemia (AML), neuroblastoma, lymphomas, and sarcomas.

NK cells were first described as being natural killers because they don’t actually look for something specific. They check if a cell is presenting the appropriate amount of normal molecules, and if it’s not, NK cells detect it as sick or dangerous and kill that cell.

NK cells function similar to the border patrol. When a person enters the border patrol office, the officer isn’t really looking for a specific person to target. He or she is observing whether or not you look suspicious, are carrying anything dangerous with you, or if you have a valid passport. As long as you have what you need to be legal and don’t look suspicious, the border patrol will leave you alone.

Tumor cells fail the natural killer’s “inspections.” They stop showing their passports, which for cells is a protein called an MHC molecule. Due to their rapid growth, tumor cells also start outstripping normal nutrients, which causes them to express stress signals. All of these make them a target to NK cells.

Although natural killer cells are agents that our bodies naturally produce, cancer patients have very low numbers of natural killer cells, and the NK cells they have don’t function normally. Current chemotherapy also kills off a patient’s own natural killer cells. To add to this, tumors have developed ways of escaping some of the natural killer cell functions.

The next step of our research project includes administering NK cells to patients in clinical trials. Some clinical trials have been done where they’ve given natural killer cells, but they’ve only been administered in small numbers. Under careful observation, our trial will escalate the dose of natural killer cells to about a hundred times more than previously given. Patients will be monitored closely to make sure we don’t see bad long-term effects. Thanks to two different St. Baldrick’s grants, we have been able to gather the data to start this clinical trial, which I hope will begin this year.

With the support of St. Baldrick’s donors and volunteers, I believe there will be more discoveries for cures on the way. I’m optimistic that we’ll be providing new therapies and treatments that are much less toxic as well as we focus on finding very intelligent and targeted ways of treating cancer.

Check out Dr. Lee’s work in this video of natural killer cells killing green-labeled neuroblastoma cancer cells:

Source: Denman CJ, Senyukov VV, Somanchi SS, Phatarpekar PV, Kopp LM, et al. (2012) Membrane-Bound IL-21 Promotes Sustained Ex Vivo Proliferation of Human Natural Killer Cells. PLoS ONE 7(1): e30264. doi:10.1371/journal.pone.0030264

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