1. Attenuation of natural killer cell functions by capsaicin through a direct and TRPV1-independent mechanism.
- Author
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Kim HS, Kwon HJ, Kim GE, Cho MH, Yoon SY, Davies AJ, Oh SB, Lee H, Cho YK, Joo CH, Kwon SW, Kim SC, and Kim YK
- Subjects
- Animals, Apoptosis, Blotting, Western, Calcium metabolism, Cell Proliferation, Cytokines genetics, Cytokines metabolism, Glioma drug therapy, Glioma immunology, Humans, Killer Cells, Natural drug effects, Killer Cells, Natural pathology, Male, Mice, Mice, Inbred C57BL, RNA, Messenger genetics, Real-Time Polymerase Chain Reaction, Reverse Transcriptase Polymerase Chain Reaction, Stomach Neoplasms drug therapy, Stomach Neoplasms immunology, TRPV Cation Channels genetics, Tumor Cells, Cultured, Capsaicin pharmacology, Glioma pathology, Killer Cells, Natural immunology, Sensory System Agents pharmacology, Stomach Neoplasms pathology, TRPV Cation Channels metabolism
- Abstract
The assessment of the biological activity of capsaicin, the compound responsible for the spicy flavor of chili pepper, produced controversial results, showing either carcinogenicity or cancer prevention. The innate immune system plays a pivotal role in cancer pathology and prevention; yet, the effect of capsaicin on natural killer (NK) cells, which function in cancer surveillance, is unclear. This study found that capsaicin inhibited NK cell-mediated cytotoxicity and cytokine production (interferon-γ and tumor necrosis factor-α). Capsaicin impaired the cytotoxicity of NK cells, thereby inhibiting lysis of standard target cells and gastric cancer cells by modulating calcium mobilization in NK cells. Capsaicin also induced apoptosis in gastric cancer cells, but that effect required higher concentrations and longer exposure times than those required to trigger NK cell dysfunction. Furthermore, capsaicin inhibited the cytotoxicity of isolated NK cells and of an NK cell line, suggesting a direct effect on NK cells. Antagonists of transient receptor potential vanilloid subfamily member 1 (TRPV1), a cognate capsaicin receptor, or deficiency in TRPV1 expression failed to prevent the defects induced by capsaicin in NK cells expressing functional TRPV1. Thus, the mechanism of action of capsaicin on NK cells is largely independent of TRPV1. Taken together, capsaicin may have chemotherapeutic potential but may impair NK cell function, which plays a central role in tumor surveillance., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2014
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