Foxp3 expression in human cancer cells

Vaios Karanikas¹ , Matthaios Speletas¹ , Maria Zamanakou¹ , Fani Kalala¹ , Gedeon Loules¹ , Theodora Kerenidi² , Angeliki K Barda¹ , Konstantinos I Gourgoulianis² and Anastasios E Germenis¹

¹Cancer Immunology Unit, Department of Immunology and Histocompatibility, School of Medicine, University of Thessaly, University Hospital of Larissa, GR-411 10 Larissa, Greece

²Department of Respiratory Medicine, School of Medicine, University of Thessaly, University Hospital of Larissa, GR-411 10 Larissa, Greece

author email corresponding author email

Journal of Translational Medicine 2008, 6:19doi:10.1186/1479-5876-6-19


Published:	22 April 2008

Abstract

Objective

Transcription factor forkhead box protein 3 (Foxp3) specifically characterizes the thymically derived naturally occurring regulatory T cells (Tregs). Limited evidence indicates that it is also expressed, albeit to a lesser extent, in tissues other than thymus and spleen, while, very recently, it was shown that Foxp3 is expressed by pancreatic carcinoma. This study was scheduled to investigate whether expression of Foxp3 transcripts and mature protein occurs constitutively in various tumor types.

Materials and methods

Twenty five tumor cell lines of different tissue origins (lung cancer, colon cancer, breast cancer, melanoma, erythroid leukemia, acute T-cell leukemia) were studied. Detection of Foxp3 mRNA was performed using both conventional RT-PCR and quantitative real-time PCR while protein expression was assessed by immunocytochemistry and flow cytometry, using different antibody clones.

Results

Foxp3 mRNA as well as Foxp3 protein was detected in all tumor cell lines, albeit in variable levels, not related to the tissue of origin. This expression correlated with the expression levels of IL-10 and TGFb1.

Conclusion

We offer evidence that Foxp3 expression, characterizes tumor cells of various tissue origins. The biological significance of these findings warrants further investigation in the context of tumor immune escape, and especially under the light of current anti-cancer efforts interfering with Foxp3 expression.