Some cancer cells that are irradiated appear to express proteins that promote the body's immune system. Leukopheresis product from HemaCare was key to this immunotherapy research.
Radiotherapy has long been used in the treatment of cancer. By damaging DNA, leading to cellular death, radiation therapy kills cancerous tissue; radiation beams can be sculpted such that normal tissue is largely spared. This type of cancer treatment has been known to be synergistic with chemotherapy.
Now, research indicates that radiotherapy may also give a closely watched form of treatment, cancer immunotherapy, a boost. Immunotherapy has turned heads in recent years as a potentially powerful method to harness the immune system, often in the form of T cells launching devastating attacks on cancer cells. But the force of immunotherapy is not relentless. T cells can become "anergic" and cease to attack target cells.
The recent research has revealed that some cancer cells as a consequence of radiotherapy may actually express signals that induce T cells to continue the fight. Researchers subjected several human colorectal tumor cell lines to radiation and found that some (but not all) of the lines proceeded to overexpress the proteins OX-40L and 4-1BBL, which stimulate T cells.
To test whether such irradiated cells were in fact more efficiently killed by T cells, the researchers needed a source for T cells, and for that they turned to HemaCare. Leukapheresis collections obtained from HemaCare were used to prepare CD8+ T cells specific for colorectal cells. The researchers found that, indeed, the irradiated cells that were over-expressing OX-40L and 4-1BBL contributed to the activation of T cells and to T cell-mediated killing. Blocking both OX-40L and 4-1BBL reversed this effect.
Further research is needed to assess the context in which radiotherapy can enhance immunotherapy in the human body. If this enhancement is observable in many cancers, it would provide a rationale for combining these two modes of treatment that would signify double trouble for cancer.
HemaCare is delighted to have supplied the leukapheresis product that served as a basis for experiments. We can provide the same for you, and we also offer CD8+ cytotoxic T cells. Call us at (877) 397-3087 for questions or to place an order.
- Kamari A and Garrett-Benson C. Effector function of CTLs is increased by irradiated colorectal tumor cells that modulate OX-40L and 4-1BBL and is reversed following dual blockade. BMC Res Notes 2016;9:92-106.