[Frontiers in Bioscience 14, 159-166, January 1, 2009]

Epidermal growth factor receptor modulates the tumorigenic potential of melanoma

Arlhee Diaz1, Eduardo Suarez1, Rances Blanco1, Armando Lopez1, Enrique Montero1

1Department of Experimental Immunotherapy, Center of Molecular Immunology, P.O. Box 16040, Havana 11600, Cuba

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and Methods 3.1. Antibodies
3.2. Animals
3.3. Cell culture
3.4. Immunoprecipitation
3.5. Western blots
3.6. Total RNA isolation
3.7. cDNA synthesis and polymerase chain reaction (PCR) amplification of human EGFR
3.8. Immunohistochemistry
3.9. Animal irradiation
3.10. Tumor growth in mice
3.11. Statistical analysis
4. Results
4.1. Expression of EGFR in B16F10 cells modulates their tumorigenic potential in vivo
4.2. Transgenic cells downregulate the human EGFR expression growing as solid tumors in mice
4.3. Persistent expression of EGFR in transfected B16F10 melanoma developed in immunocompromised C57BL/6 mice
4.4. EGFR permanent transgene downregulation in B16F10 melanoma after in vivo passage in immunocompetent C57BL/6 mice
5. Discussion
6. Acknowledgment
7. References

1. ABSTRACT

Potential contribution of the Epidermal Growth Factor Receptor (EGFR) in melanoma immunobiology remains unclear, in part due to a lack of experimental models. We demonstrated previously that B16F10 melanoma transfected with the full length cDNA of the human EGFR increases the tumor cell proliferation in vitro. To further study its contribution in vivo, EGFR-transfected B16F10 cells were inoculated in syngenic C57BL/6 mice and its tumorigenic capacity was compared with the parental melanoma. Contrary to the observed in vitro effect, EGFR-transfected B16F10 cells displayed a delayed tumor growth rate in vivo, correlating inversely to the transgene expression. Interestingly, resulting tumors showed a downregulation of the EGFR transgene expression. Contrastingly, parental and EGFR-transfected B16F10 cells exhibited a similar tumorigenic potential in immunocompromised subjects, persisting the EGFR transgene expression. These results document the adaptability of melanoma to growth in immunocompetent individuals. Moreover, the potential EGFR expression during the melanoma outgrowth that would be downregulated by interacting with the host immune system during the tumor evolution is not excluded and which may be dissected in this model.