title: Proteomic identification of the wt-p53-regulated tumor cell secretome.
abstract: Tumor-stroma interactions play a major role in tumor development, maintenance and progression. Yet little is known on how the genetic alterations that underlie cell transformation elicit cell extrinsic changes modulating heterotypic cell interactions. We hypothesized that these events involve a modification in the complement of secreted proteins by the cell, acting as mediators of intercellular communication. To test this hypothesis, we examined the role of wt-p53, a major tumor suppressor, on the tumor microenvironment through its regulation of secreted factors. Using a combination of 2-DE and cICAT proteomic techniques, we found a total of 111 secreted proteins, 39 of which showed enhanced and 21 inhibited secretion in response to wt-p53 expression. The majority of these were not direct targets of p53 transcription factor activity, suggesting a novel role for wt-p53 in the control of intracellular protein trafficking and/or secreted protein stability. Evidence for p53-controlled post-translational modifications on nine secreted proteins was also found. These findings will enhance our understanding of wt-p53 modulated interactions of the tumor with its environment.
authors.affiliation: Laboratory of Molecular Neuro-Oncology, Department of Neurosurgery, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: F W
authors.initials: FW
authors.lastname: Khwaja
authors.forename: P
authors.initials: P
authors.lastname: Svoboda
authors.forename: M
authors.initials: M
authors.lastname: Reed
authors.forename: J
authors.initials: J
authors.lastname: Pohl
authors.forename: B
authors.initials: B
authors.lastname: Pyrzynska
authors.forename: E G
authors.initials: EG
authors.lastname: Van Meir
mesh_terms: D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic; D015180:Electrophoresis, Gel, Two-Dimensional; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000378:metabolism*; D006801:Humans; D007553:Isotope Labeling; D009363:Neoplasm Proteins / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D020543:Proteome; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
chemical_list: D009363:Neoplasm Proteins; D020543:Proteome; D016159:Tumor Suppressor Protein p53