Abstract
Background: Enzymatic activity levels of serum CD26/ dipeptidylpeptidase (DPP) IV in oral cancer patients are lower than those in healthy subjects. However, the mechanism for this decrease is not yet fully understood. Materials and Methods: The influence of malignant cell-derived cytokines on cell surface CD26/DPP IV expression in human T cells was analyzed using an oral squamous cell carcinoma (SCC) cell line, KB, and peripheral blood T cells. Results: Tumor growth factor (TGF)-β1 in KB-conditioned medium (KBCM) down-regulated CD26/DPPIV expression in T cells, which was responsible for the decreased DPPIV activities in the cultured supernatant. Expression p27kip in T cells was maintained in addition to G1 arrest when cultured with KBCM but was abolished by inclusion of anti-TGF-β1 antibody. Conclusion: SCC-derived TGF-β1 down-regulates CD26/ DPPIV expression in T cells, resulting in decreased serum CD26/DPPIV activity in oral cancer patients.
Footnotes
- Received September 1, 2003.
- Accepted December 28, 2003.
- Copyright© 2004 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved