Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Oral Communication Abstract - S2c

TRANSFORMATION OF TOBACCO PLANTS EXPRESSING MELANOMA EPITOPES FOR VACCINES PRODUCTION

BARBANTE A.*, CASTIGLIONE S.*, SALA M.**, GARÇIA F.***, FIRAT H.***, LANGLADEDEMOYEN P.***

*) Department of Biology, Univ. of Milano

**) Unité de Retrovirologie Moleculaire, Institut Pasteur, Paris

***) Unité d’ImmunitéCellulaire Antivirale, Institut Pasteur, Paris

melanoma, epitopes, vaccine, transgenic, tobacco

Melanoma is a malignant tumour that originates from melanocytes, the producer cells of melanin pigment. Melanoma is the most serious form of skin cancer, accounting for about 4% of skin cancer cases, but causing 79% of skin cancer deaths.

Melanoma is the sixth most common cancer in men and the seventh in women. The number of cases worldwide is increasing faster than any other form of cancer, especially in those geographical areas (USA and Europe) where the population is largely white and the climate is hot and sunny. Recent climatic changes in these areas are most likely contributing to this increase. Worldwide, the incidence for melanoma in the year 2000 was 132,600 with 37,000 deaths. Melanoma is curable in 85-95% of individuals if the disease is caught in the earliest stages, but once the cancer advances it is difficult to treat and the possibility to overcome the disease are reduce as consequence.

It has been documented that CTL-mediated protection plays a fundamental role against human melanoma, and tumor-derived CTL epitopes have been identified.

In order to produce a plant-derived edible vaccine against melanoma, plants are being engineered to produce these epitopes. To this purpose, the DNA encoding ten epitopes of human melanoma were fused to the hepatitis B virus middle envelope protein (HbsAg) and cloned in pgreen0229, a plasmid vector able to express heterologous proteins in plants. The HbsAg is expected to enable the production of virus like particles , which are needed for triggering the immune response after providing the vaccine systemically. The plasmid construct contained the above described transgene under the control of the tandemly repeated constitutive CaMV 35 S promoter and the selectable bar gene, that confers resistance to the herbicide phosphinotricin.

At first, leaf discs of Nicotiana tabacum (cv Petit Havana SR1) have been transformed by Agrobacterium tumefaciens and Genetic Modified Plants expressing a suitable vaccine against melanoma cancer have been produced. The stable integration of the exogenous DNA sequences was verified by PCR and further confirmed by Southern blot analyses. Antigen production will be verified in the transgenic plants and conditions will be optimised for its accumulation in the plant tissue.