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author:("arabis, Jiri")
1.  Isolation and characterization of mouse and human esophageal epithelial cells in 3D organotypic culture 
Nature protocols  2012;7(2):235-246.
This protocol describes the isolation and characterization of mouse and human esophageal epithelial cells and the application of 3D organotypic culture (OTC), a form of tissue engineering. This model system permits the interrogation of mechanisms underlying epithelial-stromal interactions. We provide guidelines for isolating and cultivating several sources of epithelial cells and fibroblasts, as well as genetic manipulation of these cell types, as a prelude to their integration into OTC. The protocol includes a number of important applications, including histology, immunohistochemistry/immunofluorescence, genetic modification of epithelial cells and fibroblasts with retroviral and lentiviral vectors for overexpression of genes or RNA interference strategies, confocal imaging, laser capture microdissection, RNA microarrays of individual cellular compartments and protein-based assays. The OTC (3D) culture protocol takes 15 d to perform.
doi:10.1038/nprot.2011.437
PMCID: PMC3505594  PMID: 22240585
2.  Deletion of p120-catenin results in a tumor microenvironment with inflammation and cancer that establishes it as a tumor suppressor gene 
Cancer cell  2011;19(4):470-483.
Summary
P120ctn interacts with E-cadherin, but no formal proof that p120ctn functions as a bone fide tumor suppressor gene has emerged. We report herein that p120ctn loss leads to tumor development in mice. We have generated a conditional knockout model of p120ctn whereby mice develop pre-neoplastic and neoplastic lesions in the oral cavity, esophagus and squamous forestomach. Tumor derived cells secrete granulocyte macrophage colony stimulating factor (GM-CSF), macrophage colony stimulating factor (M-CSF), monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor-α (TNFα). The tumors contain significant desmoplasia and immune cell infiltration. Immature myeloid cells comprise a significant percentage of the immune cells present, and likely participate in fostering a favorable tumor microenvironment, including the activation of fibroblasts.
doi:10.1016/j.ccr.2011.02.007
PMCID: PMC3077713  PMID: 21481789
3.  IMP-1 displays crosstalk with K-Ras and modulates colon cancer cell survival through the novel pro-apoptotic protein CYFIP2 
Cancer research  2011;71(6):2172-2182.
Insulin-like growth factor 2 mRNA-binding protein-1 (IMP-1) is an oncofetal protein that binds directly to and stabilizes oncogenic c-Myc and regulates in turn its post-transcriptional expression and translation. In contrast to normal adult tissue, IMP-1 is re-expressed and/or overexpressed in human cancers. We demonstrate that knock-down of c-Myc in human colon cancer cell lines increases the expression of mature let-7 miRNA family members and downregulates several of its mRNA targets: IMP-1, Cdc34, and K-Ras. We further demonstrate that loss of IMP-1 inhibits Cdc34, Lin-28B, and K-Ras, and suppresses SW-480 cell proliferation and anchorage-independent growth, and promotes caspase and lamin-mediated cell death. We also found that IMP-1 binds to the coding region and 3′UTR of K-Ras mRNA. RNA microarray profiling and validation by reverse transcription PCR reveals that the p53-inducible pro-apoptotic protein, CYFIP2, is upregulated in IMP-1 knock-down SW480 cells, a novel finding. We also show that overexpression of IMP-1 increases c-Myc and K-Ras expression, and LIM2405 cell proliferation. Furthermore, we show that loss of IMP-1 induces Caspase-3 and Parp–mediated apoptosis, and inhibits K-Ras expression in SW480 cells, which is rescued by CYFIP2 knock-down. Importantly, analysis of 228 patients with colon cancers reveals that IMP-1 is significantly upregulated in differentiated colon tumors (p ≤ 0.0001) and correlates with K-Ras expression (r=0.35, p ≤ 0.0001) relative to adjacent normal mucosa. These findings indicate that IMP-1, interrelated with c-myc, acts upstream of K-Ras to promote survival through a novel mechanism that may be important in colon cancer pathogenesis.
doi:10.1158/0008-5472.CAN-10-3295
PMCID: PMC3059369  PMID: 21252116
IMP-1; c-Myc; Cdc34; CYFIP2; K-Ras
4.  EGFR and mutant p53 expand esophageal cellular subpopulation capable of epithelial-to-mesenchymal transition through ZEB transcription factors 
Cancer research  2010;70(10):4174-4184.
Transforming growth factor (TGF)-β is a potent inducer of epithelial to mesenchymal transition (EMT). However, it remains elusive as to which molecular mechanisms determine the cellular capacity to undergo EMT in response to TGF-β. We have found that both epidermal growth factor receptor (EGFR) overexpression and mutant p53 tumor suppressor genes contribute to enrichment of an EMT-competent cellular subpopulation amongst telomerase-immortalized human esophageal epithelial cells during malignant transformation. EGFR overexpression triggers oncogene-induced senescence, accompanied by induction of cyclin dependent kinase inhibitors p15INK4B, p16INK4A and p21. Interestingly, a subpopulation of cells emerges by negating senescence without loss of EGFR overexpression. Such cell populations express increased levels of zinc finger E-box binding (ZEB) transcription factors ZEB1 and ZEB2, and undergo EMT upon TGF-β stimulation. Enrichment of EMT-competent cells was more evident in the presence of p53 mutation, which diminished EGFR-induced senescence. RNA interference directed against ZEB resulted in induction of p15INK4B and p16INK4A, reactivating the EGFR-dependent senescence program. Importantly, TGF-β-mediated EMT did not take place when cellular senescence programs were activated by either ZEB knockdown or activation of wild-type p53 function. Thus, senescence checkpoint functions activated by EGFR and p53 may be evaded through the induction of ZEB, thereby allowing expansion of an EMT-competent unique cellular subpopulation, providing novel mechanistic insights into the role of ZEB in esophageal carcinogenesis.
doi:10.1158/0008-5472.CAN-09-4614
PMCID: PMC3007622  PMID: 20424117
EGFR; EMT; senescence; ZEB1; ZEB2
5.  A subpopulation of mouse esophageal basal cells has properties of stem cells with the capacity for self-renewal and lineage specification 
The Journal of Clinical Investigation  2008;118(12):3860-3869.
The esophageal epithelium is a prototypical stratified squamous epithelium that exhibits an exquisite equilibrium between proliferation and differentiation. After basal cells proliferate, they migrate outward toward the luminal surface, undergo differentiation, and eventually slough due to apoptosis. The identification and characterization of stem cells responsible for the maintenance of the esophageal epithelium remains elusive. Here, we employed Hoechst dye extrusion and BrdU label–retaining assays to identify in mice a potential esophageal stem cell population that localizes to the basal cell compartment. The self-renewing capacity of this population was characterized using a clonogenic assay and a 3D organotypic culture model. The putative esophageal stem cells were also capable of epithelial reconstitution in vivo in direct esophageal epithelial injury models. In both the 3D organotypic culture and direct mucosal injury models, the putative stem cells gave rise to undifferentiated and differentiated cells. These studies therefore provide a basis for understanding the regenerative capacity and biology of the esophageal epithelium when it is faced with injurious insults.
doi:10.1172/JCI35012
PMCID: PMC2579884  PMID: 19033657
6.  CCN3 controls 3D spatial localization of melanocytes in the human skin through DDR1 
The Journal of Cell Biology  2006;175(4):563-569.
Melanocytes reside within the basal layer of the human epidermis, where they attach to the basement membrane and replicate at a rate proportionate to that of keratinocytes, maintaining a lifelong stable ratio. In this study, we report that coculturing melanocytes with keratinocytes up-regulated CCN3, a matricellular protein that we subsequently found to be critical for the spatial localization of melanocytes to the basement membrane. CCN3 knockdown cells were dissociated either upward to the suprabasal layers of the epidermis or downward into the dermis. The overexpression of CCN3 increased adhesion to collagen type IV, the major component of the basement membrane. As the receptor responsible for CCN3-mediated melanocyte localization, we identified discoidin domain receptor 1 (DDR1), a receptor tyrosine kinase that acts as a collagen IV adhesion receptor. DDR1 knockdown decreased melanocyte adhesion to collagen IV and shifted melanocyte localization in a manner similar to CCN3 knockdown. These results demonstrate an intricate and necessary communication between keratinocytes and melanocytes in maintaining normal epidermal homeostasis.
doi:10.1083/jcb.200602132
PMCID: PMC2064593  PMID: 17101694

Results 1-6 (6)