Molecular and Functional Characteristics of Airway Epithelium under Chronic Hypoxia.

Localized and chronic hypoxia of airway mucosa is a common feature of progressive respiratory diseases, including cystic fibrosis (CF). However, the impact of prolonged hypoxia on airway stem cell function and differentiated epithelium is not well elucidated. Acute hypoxia alters the transcription and translation of many genes, including the CF transmembrane conductance regulator (CFTR). CFTR-targeted therapies (modulators) have not been investigated in vitro under chronic hypoxic conditions found in CF airways in vivo. Nasal epithelial cells (hNECs) derived from eight CF and three non-CF participants were expanded and differentiated at the air-liquid interface (26-30 days) at ambient and 2% oxygen tension (hypoxia). Morphology, global proteomics (LC-MS/MS) and function (barrier integrity, cilia motility and ion transport) of basal stem cells and differentiated cultures were assessed. hNECs expanded at chronic hypoxia, demonstrating epithelial cobblestone morphology and a similar proliferation rate to hNECs expanded at normoxia. Hypoxia-inducible proteins and pathways in stem cells and differentiated cultures were identified. Despite the stem cells' plasticity and adaptation to chronic hypoxia, the differentiated epithelium was significantly thinner with reduced barrier integrity. Stem cell lineage commitment shifted to a more secretory epithelial phenotype. Motile cilia abundance, length, beat frequency and coordination were significantly negatively modulated. Chronic hypoxia reduces the activity of epithelial sodium and CFTR ion channels. CFTR modulator drug response was diminished. Our findings shed light on the molecular pathophysiology of hypoxia and its implications in CF. Targeting hypoxia can be a strategy to augment mucosal function and may provide a means to enhance the efficacy of CFTR modulators.

PTU, a novel ureido-fatty acid, inhibits MDA-MB-231 cell invasion and dissemination by modulating Wnt5a secretion and cytoskeletal signaling.

Migration and invasion promote tumor cell metastasis, which is the leading cause of cancer death. At present there are no effective treatments. Epidemiological studies have suggested that ω-3 polyunsaturated fatty acids (PUFA) may decrease cancer aggressiveness. In recent studies epoxide metabolites of ω-3 PUFA exhibited anti-cancer activity, although increased in vivo stability is required to develop useful drugs. Here we synthesized novel stabilized ureido-fatty acid ω-3 epoxide isosteres and found that one analogue - p-tolyl-ureidopalmitic acid (PTU) - inhibited migration and invasion by MDA-MB-231 breast cancer cells in vitro and in vivo in xenografted nu/nu mice. From proteomics analysis of PTU-treated cells major regulated pathways were linked to the actin cytoskeleton and actin-based motility. The principal finding was that PTU impaired the formation of actin protrusions by decreasing the secretion of Wnt5a, which dysregulated the Wnt/planar cell polarity (PCP) pathway and actin cytoskeletal dynamics. Exogenous Wnt5a restored invasion and Wnt/PCP signalling in PTU-treated cells. PTU is the prototype of a novel class of agents that selectively dysregulate the Wnt/PCP pathway by inhibiting Wnt5a secretion and actin dynamics to impair MDA-MB-231 cell migration and invasion.

Aryl-urea fatty acids that activate the p38 MAP kinase and down-regulate multiple cyclins decrease the viability of MDA-MB-231 breast cancer cells.

We recently developed a novel aryl-urea fatty acid (CTU; 16({[4-chloro-3-(trifluoromethyl)phenyl]carbamoyl}amino)hexadecanoic acid) that impaired the viability of MDA-MB-231 breast cancer cells in vitro and in mouse xenograft models in vivo. At present there is a deficiency of information on the structural requirements for the activity of CTU. Our initial study suggested that electron withdrawing groups were required on the aryl ring, and in this study we further evaluated the influence of the electronic properties of aromatic substitution on the capacity of CTU analogues to decrease MDA-MB-231 breast cancer cell viability. Analogues that contained strong electron-withdrawing groups in the meta- and para-positions of the aryl ring exhibited improved activity over CTU. Effective analogues down-regulated the cyclins D1, E1 and B1, and the cyclin-dependent kinases (CDKs) 4 and 6, that form complexes to coordinate cell cycle progression. Active CTU analogues also stimulated the phosphorylation and activation of the p38 MAP kinase signalling pathway in cells and both decreased proliferation (5-bromo-2'-deoxyuridine (brdU) incorporation) and activated apoptosis (executioner caspase-3/7 activity). These agents offer a new approach to target the cell cycle at multiple phases in order to efficiently prevent cancer cell expansion. Inclusion of the present structural information in drug design approaches could enhance the development of optimal analogues of aryl-urea fatty acids as potential anti-cancer agents.