Project description:Hsp70 inhibition affects many signaling pathways. We established how these effects are translated into changes in gene expression. Hsp70 is a promising anti-cancer target, and several inhibitors of Hsp70 have been recently developed. Interest to Hsp70 inhibitors as drug prototypes is, however, somewhat hampered by potential similarity of their physiological effects to effects of already well-developed Hsp90 inhibitors. JG-98 series of inhibitors is unique in its ability to target an allosteric site in the ATPase domain of Hsp70, which disrupts its interaction with a co-chaperone Bag3 and affects a variety of signaling pathways important for cancer development and survival. Here, we used the Broad Institute Connectivity Map platform to evaluate physiological effects of JG-98, and found that these effects are dissimilar from effects of Hsp90 inhibitors, thus justifying further development of this compound series. Further, using gene expression data and ActivSignal IPAD platform, we identified pathways modulated by JG-98. Some of these pathways were affected by JG-98 in Bag3-dependent and some pathways in Bag3-independent manner, indicating multiple mechanisms of JG-98 action. Using pooled shRNA genetic screen, we established gene sets that modulate the response of cancer cells to JG-98. Based on genetic and gene expression information, we developed approaches to predict potent combinations of JG-98 with known drugs. These predictions were validated by demonstrating that proteasome, RNApol II, Akt and RTK inhibitors synergize with anti-cancer effects of JG-98. Overall, in this study we analyze unique effects of Hsp70 inhibitors of JG-98 series on cell physiology and define potential drug combinations for clinical use of these inhibitors.
Project description:The major heat shock protein Hsp70 has been shown to form a complex with a scaffold protein Bag3, linking it to multiple signaling pathways. Via these interactions, the Hsp70-Bag3 module functions as a proteotoxicity sensor that controls cell signaling. Here, as a tool to identify signaling pathways regulated by this complex, we utilized JG-98, an allosteric inhibitor of Hsp70 that blocks its interaction with Bag3. Gene expression profiling followed by the pathway analysis indicated that a set of signaling pathways including the unfolded protein response (UPR) was activated by JG-98. Surprisingly, only the translation initiation factor eIF2a-associated branch of the UPR was activated under these conditions, while other UPR branches mediating induction of ER chaperones were not induced, suggesting that the response was not related to ER proteotoxicity and thus to ER-associated kinase PERK1. Indeed, induction of the UPR genes under these conditions was dependent on activation of a distinct cytoplasmic eIF2a kinase, HRI. We demonstrated that the Hsp70-Bag3 complex directly interacted with HRI and regulated phosphorylation of eIF2a upon induction of cytoplasmic proteotoxicity. Therefore, we uncovered a novel signaling response, which regulates cell death upon the buildup of abnormal protein species in cytoplasm via an Hsp70-Bag3-HRI-eIF2a axis.
Project description:JG-98 reduces migration of macrophages. We assessed how this compound affects expression of genes associated with motility and migration. A number of motility/migration genes were significantly downregulated.
Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:To study effect of VRK1 deletion on spermatogenesis of the mouse, transciptomic analysis of genes in postnatal 8-day testicular cells of wild type and VRK1-deficient Mus musculus was performed.