Cytoplasmic localization of the cell polarity factor scribble supports liver tumor formation and tumor cell invasiveness.

The loss of epithelial cell polarity plays an important role in the development and progression of liver cancer. However, the specific molecular mechanisms supporting tumor initiation and progression are poorly understood. In this study, transcriptome data and immunofluorescence stains of tissue samples derived from hepatocellular carcinoma (HCC) patients revealed that overexpression associated with cytoplasmic localization of the basolateral cell polarity complex protein scribble (Scrib) correlated with poor prognosis of HCC patients. In comparison with HCC cells stably expressing wild-type Scrib (ScribWT ), mutated Scrib with enforced cytoplasmic enrichment (ScribP305L ) induced AKT signaling through the destabilization of phosphatase and tensin homolog (PTEN) and PH domain and leucine-rich repeat protein phosphatase 1 (PHLPP1). Cytoplasmic ScribP305L stimulated a gene signature and a phenotype characteristic for epithelial to mesenchymal transition (EMT) and HCC cell invasiveness. ScribP305L -dependent invasion was mediated by the activator protein 1 (AP-1) constituents ATF2 and JunB through induction of paracrine-acting secreted protein acidic and cysteine-rich (SPARC). Coexpression of ScribP305L and the oncogene c-MYC through hydrodynamic gene delivery in mouse livers promoted tumor formation and increased abundance of pAKT, pATF2, and SPARC in comparison with controls. Finally, cytoplasmic Scrib localization correlated with AKT and ATF2 phosphorylation in human HCC tissues, and the ScribP305L -dependent gene signature was enriched in cancer patients with poor prognosis. CONCLUSION: Perturbation of hepatocellular polarity due to overexpression and cytoplasmic enrichment of Scrib supports tumor initiation and HCC cell dissemination through specific molecular mechanisms. Biomarker signatures identified in this study can be used for the identification of HCC patients with higher risk for the development of metastasis. (Hepatology 2018;67:1842-1856).

Neutrophil Granulocytes in Ovarian Cancer - Induction of Epithelial-To-Mesenchymal-Transition and Tumor Cell Migration.

BACKGROUND: Ovarian cancer (OvCa) is a highly aggressive malignoma with a tumor-promoting microenvironment. Infiltration of polymorphonuclear neutrophils (PMN) is frequently seen, raising the question of their impact on tumor development. In that context, effects of PMN on human ovarian cancer cells were assessed. METHODS: Human epithelial ovarian cancer cells were incubated with human PMN, lysate of PMN, or neutrophil elastase. Morphological alterations were observed by time-lapse video-microscopy, and the underlying molecular mechanism was analyzed by flow cytometry and Western blotting. Functional alternations were assessed by an in vitro wound healing assay. In parallel, a large cohort of n=334 primary OvCa tissue samples of various histological subtypes was histologically evaluated. RESULTS: Co-cultivation of cancer cells with either PMN or PMN lysate causes a change of the polygonal epithelial phenotype of the cells towards a spindle shaped morphology, causing a cribriform cell growth. The PMN-induced alteration could be attributed to elastase, a major protease of PMN. Elastase-induced shape change was most likely due to the degradation of membranous E-cadherin, which results in loss of cell contacts and polarity. Moreover, in response to elastase, epithelial cytokeratins were downmodulated, in parallel with a nuclear translocation of ß-catenin. These PMN-elastase induced alterations of cells are compatible with an epithelial-to-mesenchymal transition (EMT) of the cancer cells. Following EMT, the cells displayed a more migratory phenotype. In human biopsies, neutrophil infiltration was seen in 72% of the cases. PMN infiltrates were detected preferentially in areas with low E-cadherin expression. CONCLUSION: PMN in the microenvironment of OvCa can alter tumor cells towards a mesenchymal and migratory phenotype.

In vitro blockade of adhesion of breast cancer cells to endothelial cells using anti-inflammatory drugs.

BACKGROUND: Increasing evidence suggests that a pro-inflammatory microenvironment affects distant metastasis of breast cancer cells, in particular by favoring tumor cell adhesion to endothelium. The aim of this study was to investigate the potential of different anti-inflammatory drugs to inhibit this effect in vitro. MATERIALS AND METHODS: Breast cancer cells from the metastatic cell line KM22 were incubated with activated Human umbilical vein endothelial cells (HUVECs). Tumor cell adhesion was quantified by fluorescence microscopy. The anti-inflammatory drugs ibuprofen, aspirin (acetylsalicylic acid), diclofenac, and dexamethasone were used as inhibiting agents. RESULTS: Aspirin and dexamethasone significantly reduced breast cancer cell adhesion to HUVECs (20.3%, p<0.000; and 25%, p<0.05, respectively). Ibuprofen and diclofenac did not significantly reduce tumor cell adhesion. CONCLUSION: Aspirin and dexamethasone seem to be able to partly inhibit adhesion of breast cancer cells to endothelium. Future studies should attempt to optimize this effect in vitro, in preparation for potential in vivo trials.

Breast cancer cell-derived cytokines, macrophages and cell adhesion: implications for metastasis.

BACKGROUND: Liver metastasis is associated with a proinflammatory microenvironment and up-regulation of cell adhesion molecules expressed by endothelial cells. The aim of this study was to characterize the interrelations between breast cancer cell-secreted cytokines, macrophages and E-selectin-mediated cancer cell adhesion and their role in metastasis of breast cancer. MATERIALS AND METHODS: Three metastatic breast cancer cell lines (1590, KM22, ZE) were studied. Cell culture supernatants were screened for cytokines and the potential for cytokines to increase tumor-necrosis factor-α (TNF-α) production by ANA-1-macrophages was analyzed. E-Selectin-mediated tumor cell adhesion of fluorescence labelled tumor cells was evaluated by measurement of fluorescence intensity with and without E-selectin-blocking strategies (monoclonal antibodies, cimetidine). RESULTS: Tumor-specific cytokine secretion patterns were revealed. TNF-α secretion from cultured macrophages increased after incubation with tumor supernatants. Tumor cell adhesion was significantly inhibited by cimetidine and monoclonal antibodies against E-selectin (KM22 with cimetidine, p<0.05). CONCLUSION: Breast cancer cell-secreted cytokines stimulate macrophages to produce TNF-α, a known up-regulator of E-selectin expression, and therefore cell adherence to endothelium. Inhibition of this mechanism could be an attractive therapeutic option for the prevention of breast cnacer metastasis.