RESUMO
Preventive vaccination against tumor-associated endogenous antigens is considered to be an attractive strategy for the induction of a curative immune response concomitant with a long-lasting immunologic memory. The mucin MUC1 is a promising tumor antigen, as its tumor-associated form differs from the glycoprotein form expressed on healthy cells. Due to aberrant glycosylation in tumor cells, the specific peptide epitopes in its backbone are accessible and can be bound by antibodies induced by vaccination. Breast cancer patients develop per se only low levels of T cells and antibodies recognizing tumor-associated MUC1, and clinical trials with tumor-associated MUC1 yielded unsatisfactory therapeutic effects, indicating an urgent need to improve humoral immunity against this tumor entity. Herein, we demonstrate that preventive vaccination against tumor-associated human MUC1 results in a specific humoral immune response, a slowdown of tumor progression and an increase in survival of breast tumor-bearing mice. For preventive vaccination, we used a synthetic vaccine containing a tumor-associated glycopeptide structure of human MUC1 coupled to Tetanus Toxoid. The glycopeptide consists of a 22mer huMUC1 peptide with two immune dominant regions (PDTR and GSTA), glycosylated with the sialylated carbohydrate STN on serine-17. PyMT (polyomavirus middle T-antigen) and human MUC1 double-transgenic mice expressing human tumor-associated MUC1 on breast tumor tissue served as a preclinical breast cancer model.
Assuntos
Vacinas Anticâncer/uso terapêutico , Glicopeptídeos/imunologia , Neoplasias Mamárias Experimentais/terapia , Mucina-1/imunologia , Toxoide Tetânico/imunologia , Vacinas Sintéticas/uso terapêutico , Animais , Anticorpos Monoclonais/farmacologia , Linhagem Celular Tumoral , Feminino , Humanos , Imunoglobulina G/farmacologia , Camundongos Transgênicos , Pessoa de Meia-Idade , Mucina-1/genética , Neoplasias de Mama Triplo Negativas/imunologiaRESUMO
In studies within the realm of cancer immunotherapy, the synthesis of exactly specified tumor-associated glycopeptide antigens is shown to be a key strategy for obtaining a highly selective biological reagent, that is, a monoclonal antibody that completely differentiates between tumor and normal epithelial cells and specifically marks the tumor cells in pancreas tumors. Mucin MUC1, which is overexpressed in many prevalent cancers, was identified as a promising target for this strategy. Tumor-associated MUC1 differs significantly from that expressed by normal cells, in particular by altered glycosylation. Structurally defined tumor-associated MUC1 cannot be isolated from tumor cells. We synthesized MUC1-glycopeptide vaccines and analyzed their structure-activity relationships in immunizations; a monoclonal antibody that specifically distinguishes between human normal and tumor epithelial cells was thus generated.
Assuntos
Anticorpos Monoclonais/biossíntese , Neoplasias da Mama/patologia , Mama/citologia , Vacinas Anticâncer/administração & dosagem , Glicopeptídeos/imunologia , Neoplasias Pancreáticas/diagnóstico , Feminino , HumanosRESUMO
Based on important cell-biological and biochemical results concerning the structural difference between membrane glycoproteins of normal epithelial cells and epithelial tumour cells, tumour-associated glycopeptide antigens have been chemically synthesised and structurally confirmed. Glycopeptide structures of the tandem repeat sequence of mucin MUC1 of epithelial tumour cells constitute the most promising tumour-associated antigens. In order to generate a sufficient immunogenicity of these endogenous structures, usually tolerated by the immune system, these synthetic glycopeptide antigens were conjugated to immune stimulating components: in fully synthetic two-component vaccines either with T-cell peptide epitopes or with Toll-like receptor2 lipopeptide ligands or in three-component vaccines with both these stimulants. Alternatively, the synthetic glycopeptide antigens were coupled to immune stimulating carrier proteins. In particular, MUC1 glycopeptide conjugates with Tetanus toxoid proved to be efficient vaccines inducing very strong immune responses in mice. The antibodies elicited with the fully synthetic vaccines showed selective recognition of the tumour-associated glycopeptides as was shown by neutralisation and micro-array binding experiments. After booster immunisations, most of the immune responses showed the installation of an immunological memory. Immunisation with fully synthetic three-component vaccines induced immune reactions with therapeutic effects in terms of reduction of the tumour burden in mice or in killing of tumour cells in culture, while MUC1 glycopeptide-Tetanus toxoid vaccines elicited antibodies in mice which recognised tumour cells in human tumour tissues. The results achieved so far are considered to be promising for the development of an active immunisation against tumours.
Assuntos
Vacinas Anticâncer/química , Mucina-1/química , Vacinas Sintéticas/química , Animais , Anticorpos/química , Anticorpos/imunologia , Vacinas Anticâncer/imunologia , Vacinas Anticâncer/uso terapêutico , Dendrímeros/síntese química , Dendrímeros/química , Mapeamento de Epitopos , Humanos , Mucina-1/imunologia , Neoplasias/tratamento farmacológico , Neoplasias/prevenção & controle , Linfócitos T/imunologia , Toxoide Tetânico/química , Toxoide Tetânico/imunologia , Vacinas Sintéticas/imunologia , Vacinas Sintéticas/uso terapêuticoRESUMO
A shot in the arm for cancer treatment: two MUC1 tetanus toxoid vaccines were synthesized and induced a strong immune response in mice. The antibodies elicited by the vaccines show a high selectivity for the tumor cells in mammary carcinoma tissues and also distinguish between tumor tissues at different stages.
Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Vacinas Anticâncer/farmacologia , Glicopeptídeos/imunologia , Neoplasias Mamárias Experimentais/tratamento farmacológico , Mucina-1/imunologia , Vacinas Sintéticas/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/imunologia , Neoplasias da Mama/imunologia , Neoplasias da Mama/patologia , Vacinas Anticâncer/síntese química , Vacinas Anticâncer/imunologia , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Glicopeptídeos/química , Células MCF-7 , Neoplasias Mamárias Experimentais/imunologia , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Conformação Molecular , Mucina-1/química , Vacinas Sintéticas/química , Vacinas Sintéticas/imunologiaAssuntos
Antígenos Glicosídicos Associados a Tumores/química , Vacinas Anticâncer/química , Flúor/química , Mucina-1/química , Toxoide Tetânico/química , Animais , Anticorpos/metabolismo , Neoplasias da Mama/prevenção & controle , Neoplasias da Mama/terapia , Vacinas Anticâncer/imunologia , Vacinas Anticâncer/uso terapêutico , Linhagem Celular Tumoral , Feminino , Citometria de Fluxo , Glicopeptídeos/química , Humanos , Camundongos , Vacinas Sintéticas/química , Vacinas Sintéticas/imunologia , Vacinas Sintéticas/uso terapêuticoAssuntos
Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos , Glicopeptídeos/imunologia , Soros Imunes/imunologia , Análise em Microsséries , Mucina-1/química , Mucina-1/imunologia , Neoplasias/diagnóstico , Sequência de Aminoácidos , Animais , Glicopeptídeos/síntese química , Glicopeptídeos/química , Camundongos , Dados de Sequência Molecular , Sequências Repetitivas de AminoácidosAssuntos
Antígenos de Neoplasias/imunologia , Vacinas Anticâncer , Glicopeptídeos/imunologia , Mucina-1/imunologia , Fragmentos de Peptídeos/imunologia , Toxoide Tetânico/imunologia , Vacinas Sintéticas/imunologia , Animais , Vacinas Anticâncer/síntese química , Vacinas Anticâncer/imunologia , Humanos , Sistema Imunitário/imunologia , Camundongos , Camundongos Transgênicos , Estrutura MolecularRESUMO
The addition of aluminium alkyls to terminal olefins leads to branched organoaluminium compounds which can be converted into functionalised alkanes. This carboalumination reaction is efficiently catalysed by a donor functionalised Cp-chromium(III) complex. The active catalyst is obtained by activation of the chromium(III) dichloride precursor with MAO or with a mixture of trialkylaluminium and N,N-dimethylanilinium tetrakispentaflourphenylborate. Primary aminoalkenes deactivate the catalyst whereas secondary and tertiary aminoalkenes can also be carboaluminated.