RESUMO
Enhanced sensitivity to Wnts is an emerging hallmark of a subset of cancers, defined in part by mutations regulating the abundance of their receptors. Whether these mutations identify a clinical opportunity is an important question. Inhibition of Wnt secretion by blocking an essential post-translational modification, palmitoleation, provides a useful therapeutic intervention. We developed a novel potent, orally available PORCN inhibitor, ETC-1922159 (henceforth called ETC-159) that blocks the secretion and activity of all Wnts. ETC-159 is remarkably effective in treating RSPO-translocation bearing colorectal cancer (CRC) patient-derived xenografts. This is the first example of effective targeted therapy for this subset of CRC. Consistent with a central role of Wnt signaling in regulation of gene expression, inhibition of PORCN in RSPO3-translocated cancers causes a marked remodeling of the transcriptome, with loss of cell cycle, stem cell and proliferation genes, and an increase in differentiation markers. Inhibition of Wnt signaling by PORCN inhibition holds promise as differentiation therapy in genetically defined human cancers.
Assuntos
Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Compostos Heterocíclicos de 4 ou mais Anéis/administração & dosagem , Proteínas de Membrana/genética , Proteínas Wnt/genética , Aciltransferases , Animais , Linhagem Celular Tumoral , Neoplasias Colorretais/patologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Proteínas de Membrana/antagonistas & inibidores , Camundongos , Processamento de Proteína Pós-Traducional , Células-Tronco/efeitos dos fármacos , Proteínas Wnt/antagonistas & inibidores , Via de Sinalização Wnt/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
AIMS/HYPOTHESIS: The human Fas gene (FAS) on chromosome 10q24.1 encoding a cell surface receptor involved in apoptosis was evaluated as a candidate susceptibility gene for Type I (insulin-dependent) diabetes mellitus. Apoptosis mediated by Fas is important in maintaining peripheral self-tolerance and in down-regulating the immune response and could have a role in immune-mediated beta-cell destruction. METHODS: We did a molecular scan of the entire human FAS (promoter, exons 1-9 including exon-intron boundaries and the 3'UTR) using single strand conformational polymorphism-heteroduplex analysis. RESULTS: We identified 15 mutations, of which 11 are new. Of these a g-1194A-->T and a g-295Ains give rise to alterations of transcription-factor-binding consensus sequences for c-Myb, SP-1 and NF-kappa B, respectively. A total of 1068 people from a Danish family collection comprising 138 Type I diabetic sib-pair families (289 affected and 121 unaffected offspring) and 103 Type I diabetic parent-offspring multiplex families (103 affected and 112 unaffected offspring) were typed for the three most frequent polymorphisms with high heterozygosity indices and for a FAS microsatellite. Haplotypes were established and data analysed using the extended transmission disequilibrium test, ETDT. CONCLUSION/INTERPRETATION: We found no overall evidence for linkage of the FAS polymorphisms to Type I diabetes. We conclude that it is unlikely that the Fas gene does contribute to genetic susceptibility for Type I diabetes.
Assuntos
Cromossomos Humanos Par 10 , Diabetes Mellitus Tipo 1/genética , Mutação , Receptor fas/genética , Adulto , Criança , Mapeamento Cromossômico , Primers do DNA , Dinamarca , Éxons , Feminino , Ligação Genética , Humanos , Masculino , Repetições de Microssatélites , Núcleo Familiar , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , População BrancaRESUMO
A novel microsatellite marker was found within 48.5 kb of the Fas gene. The observed heterozygosity in 160 healthy unrelated controls was 0.78. There was no evidence of linkage to type I diabetes mellitus in 120 diabetic children using the transmission disequilibrium test.
Assuntos
Diabetes Mellitus Tipo 1/genética , Ligação Genética , Repetições de Microssatélites , Polimorfismo Genético , População Branca/genética , Receptor fas/genética , Sequência de Bases , Criança , Primers do DNA , Frequência do Gene , Heterozigoto , HumanosRESUMO
Genes encoding the mosquitocidal binary toxin of Bacillus sphaericus 2362 were introduced into Synechococcus PCC6301, a cyanobacterium that can tolerate a number of potential variations in the mosquito breeding environment, and can serve as a food source for mosquito larvae. The toxin genes, preceded by a Synechococcus rbcL promoter, were located on a mobilizable Escherichia coli Synechococcus shuttle vector, which was introduced into Synechococcus PCC6301 at frequencies of 10(-5)-10(-7) exconjugants/recipient, depending on the selective conditions used. Recombinant Synechococcus exhibited significant toxicity against 2-day-old and 6-day-old Culex quinquefasciatus larvae, the concentration required to kill 50% of larvae (LC50) being 2.1 x 10(5) and 1.3 x 10(5) cells/ml respectively. Mosquitocidal activity decreased tenfold after 20 generations of non-selective growth.
