RESUMO
The Hedgehog pathway is one of the major driver pathways in pancreatic ductal adenocarcinoma. This study investigated prognostic importance of Hedgehog signaling pathway in pancreatic cancer patients who underwent a radical resection. Tumors and adjacent non-neoplastic pancreatic tissues were obtained from 45 patients with histologically verified pancreatic cancer. The effect of experimental taxane chemotherapy on the expression of Hedgehog pathway was evaluated in vivo using a mouse xenograft model prepared using pancreatic cancer cell line Paca-44. Mice were treated by experimental Stony Brook Taxane SB-T-1216. The transcript profile of 34 Hedgehog pathway genes in patients and xenografts was assessed using quantitative PCR. The Hedgehog pathway was strongly overexpressed in pancreatic tumors and upregulation of SHH, IHH, HHAT and PTCH1 was associated with a trend toward decreased patient survival. No association of Hedgehog pathway expression with KRAS mutation status was found in tumors. Sonic hedgehog ligand was overexpressed, but all other downstream genes were downregulated by SB-T-1216 treatment in vivo. Suppression of HH pathway expression in vivo by taxane-based chemotherapy suggests a new mechanism of action for treatment of this aggressive tumor.
Assuntos
Carcinoma Ductal Pancreático/tratamento farmacológico , Proteínas Hedgehog/genética , Neoplasias Pancreáticas/tratamento farmacológico , Taxoides/uso terapêutico , Transcriptoma/efeitos dos fármacos , Idoso , Animais , Carcinoma Ductal Pancreático/genética , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Camundongos Nus , Pessoa de Meia-Idade , Mutação , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Taxoides/administração & dosagem , Resultado do Tratamento , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Temporal reverse transcription-polymerase chain reaction (RT-PCR) expression analyses were performed on Trprx2, a new white clover peroxidase, with roots challenged with homologous rhizobia, heterologous rhizobia, and a pathogen, Pseudomonas syringae. Low levels of Trprx2 expression were evident in all rhizobial treatments but in P.syringae-treated clover background expression was dramatically reduced within 1 h and was undetectable in treatments inoculated for more than 3 h. Spraying 4 mM salicylic acid onto seedlings increased Trprx2 expression. These data suggest a defensive role for Trprx2 in white clover and indicate active defense suppression by the pathogen.
Assuntos
DNA Complementar/genética , DNA de Plantas/genética , Fabaceae/enzimologia , Fabaceae/genética , Peroxidase/genética , Plantas Medicinais , Sequência de Aminoácidos , Fabaceae/microbiologia , Expressão Gênica , Genes de Plantas , Dados de Sequência Molecular , Raízes de Plantas/enzimologia , Raízes de Plantas/microbiologia , Pseudomonas/fisiologia , Rhizobium/fisiologia , Homologia de Sequência de Aminoácidos , SimbioseRESUMO
PCR amplification of the small subunit (SSU) rDNA gene of 40 isolates of Nectria galligena revealed four length polymorphisms. PCR-RFLP analysis of the SSU rDNA gene divided the isolates into four categories similar, but not identical, to categories identified by Southern-RFLP analysis. Nucleotide sequence analysis revealed that isolates in three of the four SSU rDNA (18S) categories possess an intron of 363 bp, 1185 bp or 1423 bp at the NS 7 priming site. Isolates in the fourth category do not possess an intron. The nucleotide sequences of these introns did not contain the core elements characteristic of typical group I introns, nor did they exhibit a group I intron secondary structure. Homology between the introns indicates a common lineage, all three possibly having come from a larger intron and having been formed by subsequent deletions. PCR primers upstream of the SSU rDNA intron region and from within the internal transcribed spacer 1 region amplify a product specific to N. galligena, which will confirm the identity of the pathogen and reveal its 18S category in a single reaction.