Patil, A. | Search bioRxiv

bioRxiv2018

E74 like ETS transcription factor 3 (ELF3) is a negative regulator of epithelial-mesenchymal transition in bladder carcinoma

Transcription factors are known to be commonly deregulated in various cancers. The E74 like ETS transcription factor 3 (ELF3) expression is restricted to epithelial tissue. In the present study, we evaluated the role of ELF3 in the pathogenesis of bladder carcinoma (BCa) using cell line model. The cell lines with low expression of ELF3 showed increased expression of mesenchymal markers and decreased expression of epithelial markers. Immunofluorescence and immunohistochemical analysis of ELF3 showed selective expression in low-grade BCa cell lines and tumor tissues, respectively. We demonstrated that overexpression of ELF3 in UMUC3, a mesenchymal BCa cell line resulted in reduced invasion and decreased expression of mesenchymal markers. Furthermore, using publicly available data, we found that low expression of ELF3 was associated with increased risk and poor overall survival rate in BCa. In conclusion, ELF3-modulated reversal of EMT might be a useful strategy in the treatment of bladder cancer.

cancer biology↗

bioRxiv2018

Rapid Whole Cell Imaging Reveals An APPL1-Dynein Nexus That Regulates Stimulated EGFR Trafficking

Multicellular life processes such as proliferation and differentiation depend on cell surface signaling receptors that bind ligands generally referred to as growth factors. Recently, it has emerged that the endosomal system provides rich signal processing capabilities for responses elicited by these factors [1-3]. At the single cell level, endosomal trafficking becomes a critical component of signal processing, as exemplified by the epidermal growth factor (EGF) receptors of the receptor tyrosine kinase family. EGFRs, once activated by EGF, are robustly trafficked to the phosphatase-enriched peri-nuclear region (PNR), where they are dephosphorylated [4-8]. However, the details of the mechanisms regulating the movements of stimulated EGFR in time and space, i.e., towards the PNR, are not known. What endosomal regulators provide specificity to EGFR? Do modifications to the receptor upon stimulation regulate its trafficking? To understand the events leading to EGFR translocation, and especially the early endosomal dynamics that immediately follow EGFR internalization, requires the real-time, long-term, whole-cell imaging of multiple elements. Here, exploiting the advantages of lattice light-sheet microscopy [9], we show that the binding of EGF by its receptor, EGFR, triggers a transient calcium increase that peaks by 30 s, causing the desorption of APPL1 from pre-existing endosomes within one minute, the rebinding of liberated APPL1 to EGFR within three minutes, and the dynein-dependent translocation of APPL1-EGF-bearing endosomes to the PNR within five minutes. The novel, cell spanning, fast acting network that we reveal integrates a cascade of events dedicated to the cohort movement of activated EGFR receptors. Our findings support the intriguing proposal that certain endosomal pathways have shed some of the stochastic strategies of traditional trafficking, and have evolved behaviors whose predictability is better suited to signaling [10, 11]. Work presented here demonstrates that our whole cell imaging approach can be a powerful tool in revealing critical transient interactions in key cellular processes such as receptor trafficking.

cell biology↗