Signal-Oriented Pathway Analyses Reveal a Signaling Complex as a Synthetic Lethal Target for p53 Mutations
CANCER RESEARCH
Authors: Lu, Songjian; Cai, Chunhui; Yan, Gonghong; Zhou, Zhuan; Wan, Yong; Chen, Vicky; Chen, Lujia; Cooper, Gregory F.; Obeid, Lina M.; Hannun, Yusuf A.; Lee, Adrian V.; Lu, Xinghua
Abstract
Defining processes that are synthetic lethal with p53 mutations in cancer cells may reveal possible therapeutic strategies. In this study, we report the development of a signal-oriented computational framework for cancer pathway discovery in this context. We applied our bipartite graph-based functional module discovery algorithm to identify transcriptomic modules abnormally expressed in multiple tumors, such that the genes in a module were likely regulated by a common, perturbed signal. For each transcriptomic module, we applied our weighted k-pathmerge algorithm to search for a set of somatic genome alterations (SGA) that likely perturbed the signal, that is, the candidate members of the pathway that regulate the transcriptomic module. Computational evaluations indicated that our methods-identified pathways were perturbed by SGA. In particular, our analyses revealed that SGA affecting TP53, PTK2, YWHAZ, and MED1 perturbed a set of signals that promote cell proliferation, anchor-free colony formation, and epithelial-mesenchymal transition (EMT). These proteins formed a signaling complex that mediates these oncogenic processes in a coordinated fashion. Disruption of this signaling complex by knocking down PTK2, YWHAZ, or MED1 attenuated and reversed oncogenic phenotypes caused by mutant p53 in a synthetic lethal manner. This signal-oriented framework for searching pathways and therapeutic targets is applicable to all cancer types, thus potentially impacting precision medicine in cancer. (C) 2016 AACR.
Differential actin organization by vinculin isoforms: implications for cell type-specific microfilament anchorage
FEBS LETTERS
Authors: Rudiger, M; Korneeva, N; Schwienbacher, C; Weiss, EE; Jockusch, BM
Abstract
Vinculin is found in all adherens junctions, while metavinculin, a larger splice variant, is coexpressed with vinculin only in smooth and cardiac muscle. To understand the significance of metavinculin expression, we compared ligand binding between turkey vinculin and metavinculin, Residues 1-258 mere found essential for head-tail interactions in both proteins. The tail domains (VT and MVT, respectively) both bind to F-actin, However, while VT bundles F-actin, MVT generates highly viscous F-actin webs. In transfected PtK2 cells, VT causes F-actin needles or coils, while MVT-expressing cells display a diffuse F-actin distribution, Thus, the MVT-specific insert induces an F-actin supraorganization different from the VT-based form, suggesting that metavinculin has a specific role in muscle. (C) 1998 Federation of European Biochemical Societies.