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Pujana, M. A.

Publications and source records attributed to Pujana, M. A..

2 recordsLinked to original sources

Differential metabolic activity and discovery of therapeutic targets using summarized metabolic pathway models

Backgroundin spite of the increasing availability of genomic and transcriptomic data, there is still a gap between the detection of perturbations in gene expression and the understanding of their contribution to the molecular mechanisms that ultimately account for the phenotype studied. Alterations in the metabolism are behind the initiation and progression of many diseases, including cancer. The wealth of available knowledge on metabolic processes can therefore be used to derive mechanistic models that link gene expression perturbations to changes in metabolic activity that provide relevant clues on molecular mechanisms of disease and drug modes of action (MoA). In particular, pathway modules, which recapitulate the main aspects of metabolism, are especially suitable for this type of modeling.\n\nResultswe present Metabolizer, a web-based application that offers an intuitive, easy-to-use interactive interface to analyze differences in pathway module metabolic activities that can also be used for class prediction and in silico prediction of Knock-Out (KO) effects. Moreover, Metabolizer can automatically predict the optimal KO intervention for restoring a diseased phenotype. We provide different types of validations of some of the predictions made by Metabolizer.\n\nConclusionsMetabolizer is a web tool that allows understanding molecular mechanisms of disease or the MoA of drugs within the context of the metabolism by using gene expression measurements. In addition, this tool automatically suggests potential therapeutic targets for individualized therapeutic interventions.\n\nMetabolizer can be found at: http://metabolizer.babelomics.org.

bioinformatics

Subjugation of TGFβ Signaling by Human Papilloma Virus in Head and Neck Squamous Cell Carcinoma Shifts DNA Repair from Homologous Recombination to Alternative End-Joining

Purpose: Following cytotoxic therapy, 70% of patients with human papillomavirus (HPV) positive oropharyngeal head and neck squamous cell carcinoma (HNSCC) are alive at 5 years compared to 30% of those with similar HPV-negative cancer, which is thought to be due to dysregulation of DNA repair. Loss of transforming growth factor {beta} (TGF{beta}) signaling is a poorly studied consequence of HPV that could contribute to this phenotype.\n\nExperimental Design: Human HNSCC cell lines (n=9), patient-derived xenografts (n=9), tissue microarray (n=194), TCGA expression data and primary tumor specimens (n=10) were used to define the relationship between TGF{beta} competency, response to DNA damage, and type of DNA repair.\n\nResults: Analysis of HNSCC specimens in situ and in vitro showed that HPV associates with loss of TGF{beta} signaling that increases the response to radiation or cisplatin. TGF{beta} suppressed miR-182 that inhibited both BRCA1, necessary for homologous recombination repair, and FOXO3, which is required for ATM kinase activity. TGF{beta} signaling blockade by either HPV or inhibitors released this control, compromised HRR and increased response to PARP inhibition. Antagonizing miR-182 rescued the homologous recombination deficit in HPV+ cells. Loss of TGF{beta} signaling unexpectedly increased error-prone, alternative end-joining repair.\n\nConclusions: HPV-positive HNSCC cells are unresponsive to TGF{beta}. Abrogated TGF{beta} signaling compromises homologous recombination and shifts reliance on alt-EJ repair that provides a mechanistic basis for sensitivity to PARP inhibitors. The effect of HPV in HNSCC provides critical validation of TGF{beta}s role in DNA repair proficiency and further raises the translational potential of TGF{beta} inhibitors in cancer therapy.

cancer biology