Researchers studying head and neck cancer at the University of Cincinnati (OH, USA) have elucidated the immunosuppressive role of defective Kv1.3 ion channels and subsequent Ca2+ fluxes in tumor infiltrating lymphocytes in the disease. These findings suggest that the channel could be targeted to reduce head and neck tumor growth.
The study, published recently in Cancer Research, compared tumor samples with matched peripheral blood samples from 14 patients with head and neck cancer. Using electrophysiology, the authors demonstrated that T cells present in the tumor samples had a 70% reduction in functional Kv1.3 channels, which are involved in the regulation of Ca2+ levels.
The decrease in Kv1.3 levels was demonstrated to be accompanied by a decrease in Ca2+ influx in tumor infiltrating lymphocytes. As many processes in immune cells are calcium dependent, the team postulated that reduced levels of Kv1.3 may contribute to a reduced ability of the immune system to act against tumor cells.
Laura Conforti (corresponding author, University of Cincinnati) explained: “Overall our data showed that suppression of Kv1.3 channels in these lymphocytes, the cells that fight off cancer, contribute to their decreased function, raising the possibility that this channel may be used as a potential marker of functionally competent T cells that have infiltrated the tumor mass.”
In addition, it could be possible that by regulating the expression of the Kv1.3 channel at the cellular level and helping the body’s immune response fight the tumor cells, patients with head and neck cancers could have better outcomes.
Treatment for head and neck cancer currently faces several challenges; for example, tumor heterogeneity and the complex anatomy of the head and neck. These factors limit the use of conventional treatments and make alternative treatment options, such as immunotherapy, a promising prospect.
“Immunotherapies aimed to boost the immune system to fight cancer cells are showing promising results in this group of patients,” Conforti concluded. “Further studies are needed on this T cell channel to find out more about its effects on head and neck cancer and ways we can target it to improve outcomes.”
Sources: Chimote AA, Hajdu P, Sfyris AM et al; Kv1.3 channels mark functionally competent CD8+ tumor infiltrating lymphocytes in head and neck cancer. Cancer Res. DOI: 10.1158/0008-5472.CAN-16-2372 (2016) (Epub ahead of print); University of Cincinnati press release