A Screening of Native (Poly)phenols and Gut-Related Metabolites on 3D HCT116 Spheroids Reveals Gut Health Benefits of a Flavan-3-ol Metabolite.

SCOPE: Epidemiological evidence suggests that a reduced risk of colorectal cancer (CRC) is correlated with high consumption of fruits and vegetables, which are major sources of fiber and phytochemicals, such as flavan-3-ols. However, it remains unknown how these phytochemicals and their specific gut-related metabolites may alter cancer cell behavior. METHODS AND RESULTS: A focused screening using native (poly)phenols and gut microbial metabolites (GMMs) on 3D HCT116 spheroids is carried out using a high-throughput imaging approach. Dose-responses, IC50 , and long-term exposure are calculated for the most promising native (poly)phenols and GMMs. As a result, this research shows that (poly)phenol catabolites may play a key role in preventing cancer propagation. Indeed, µM concentration levels of (4R)-5-(3',4'-dihydroxyphenyl)-γ-valerolactone significantly decrease spheroid size at early stages of spheroid aggregation and gene expression of matrix metalloproteinases. CONCLUSION: A chronic exposure to (4R)-5-(3',4'-dihydroxyphenyl)-γ-valerolactone may lead to a reduced CRC risk. Daily intake of monomeric, oligomeric, and polymeric flavan-3-ols may increase the colonic concentrations of this metabolite, and, in turn, this compound may act locally interacting with intestinal epithelial cells, precancerous and cancer cells.

New 4-Aminoproline-Based Small Molecule Cyclopeptidomimetics as Potential Modulators of α4ß1 Integrin.

Integrin α4ß1 belongs to the leukocyte integrin family and represents a therapeutic target of relevant interest given its primary role in mediating inflammation, autoimmune pathologies and cancer-related diseases. The focus of the present work is the design, synthesis and characterization of new peptidomimetic compounds that are potentially able to recognize α4ß1 integrin and interfere with its function. To this aim, a collection of seven new cyclic peptidomimetics possessing both a 4-aminoproline (Amp) core scaffold grafted onto key α4ß1-recognizing sequences and the (2-methylphenyl)ureido-phenylacetyl (MPUPA) appendage, was designed, with the support of molecular modeling studies. The new compounds were synthesized through SPPS procedures followed by in-solution cyclization maneuvers. The biological evaluation of the new cyclic ligands in cell adhesion assays on Jurkat cells revealed promising submicromolar agonist activity in one compound, namely, the c[Amp(MPUPA)Val-Asp-Leu] cyclopeptide. Further investigations will be necessary to complete the characterization of this class of compounds.

Flavonoid-Derived Human Phenyl-γ-Valerolactone Metabolites Selectively Detoxify Amyloid-ß Oligomers and Prevent Memory Impairment in a Mouse Model of Alzheimer's Disease.

SCOPE: Amyloid-ß oligomers (AßO) are causally related to Alzheimer's disease (AD). Dietary natural compounds, especially flavonoids and flavan-3-ols, hold great promise as potential AD-preventive agents but their host and gut microbiota metabolism complicates identification of the most relevant bioactive species. This study aims to investigate the ability of a comprehensive set of phenyl-γ-valerolactones (PVL), the main circulating metabolites of flavan-3-ols and related dietary compounds in humans, to prevent AßO-mediated toxicity. METHODS AND RESULTS: The anti-AßO activity of PVLs is examined in different cell model systems using a highly toxic ß-oligomer-forming polypeptide (ß23) as target toxicant. Multiple PVLs, and particularly the monohydroxylated 5-(4'-hydroxyphenyl)-γ-valerolactone metabolite [(4'-OH)-PVL], relieve ß-oligomer-induced cytotoxicity in yeast and mammalian cells. As revealed by atomic force microscopy (AFM) and other in vitro assays, (4'-OH)-PVL interferes with AßO (but not fibril) assembly and actively remodels preformed AßOs into nontoxic amorphous aggregates. In keeping with the latter mode of action, treatment of AßOs with (4'-OH)-PVL prior to brain injection strongly reduces memory deterioration as well as neuroinflammation in a mouse model of AßO-induced memory impairment. CONCLUSION: PVLs, which have been validated as biomarkers of the dietary intake of flavan-3-ols, lend themselves as novel AßO-selective, candidate AD-preventing compounds.

5-(Hydroxyphenyl)-γ-Valerolactone-Sulfate, a Key Microbial Metabolite of Flavan-3-ols, Is Able to Reach the Brain: Evidence from Different in Silico, In Vitro and In Vivo Experimental Models.

Phenolic compounds have been recognized as promising compounds for the prevention of chronic diseases, including neurodegenerative ones. However, phenolics like flavan-3-ols (F3O) are poorly absorbed along the gastrointestinal tract and structurally rearranged by gut microbiota, yielding smaller and more polar metabolites like phenyl-γ-valerolactones, phenylvaleric acids and their conjugates. The present work investigated the ability of F3O-derived metabolites to cross the blood-brain barrier (BBB), by linking five experimental models with increasing realism. First, an in silico study examined the physical-chemical characteristics of F3O metabolites to predict those most likely to cross the BBB. Some of these metabolites were then tested at physiological concentrations to cross the luminal and abluminal membranes of brain microvascular endothelial cells, cultured in vitro. Finally, three different in vivo studies in rats injected with pure 5-(3',4'-dihydroxyphenyl)-γ-valerolactone, and rats and pigs fed grapes or a F3O-rich cocoa extract, respectively, confirmed the presence of 5-(hydroxyphenyl)-γ-valerolactone-sulfate (3',4' isomer) in the brain. This work highlighted, with different experimental models, the BBB permeability of one of the main F3O-derived metabolites. It may support the neuroprotective effects of phenolic-rich foods in the frame of the "gut-brain axis".

Integrin-targeted AmpRGD sunitinib liposomes as integrated antiangiogenic tools.

We report here the preparation, physico-chemical characterization, and biological evaluation of a new liposome formulation as a tool for tumor angiogenesis inhibition. Liposomes are loaded with sunitinib, a tyrosine kinase inhibitor, and decorated with cyclo-aminoprolineRGD units (cAmpRGD), efficient and selective ligands for integrin αVß3. The RGD units play multiple roles since they target the nanovehicles at the integrin αVß3-overexpressing cells (e.g. activated endothelial cells), favor their active cell internalization, providing drug accumulation in the cytoplasm, and likely take part in the angiogenesis inhibition by interfering in the αVß3-VEGFR2 cross-talk. Both in vitro and in vivo studies show a better efficacy of this integrated antiangiogenic tool with respect to the free sunitinib and untargeted sunitinib-loaded liposomes. This system could allow a lower administration of the drug and, by increasing the vector specificity, reduce side-effects in a prolonged antiangiogenic therapy.