MiR-27b is highly expressed in endothelial cells (EC) but its function in this context is poorly characterized. This study aims to investigate the effect of miR-27b on inflammatory pathways, cell cycle, apoptosis, and mitochondrial oxidative imbalances in immortalized human aortic endothelial cells (teloHAEC), human umbilical vein endothelial cells (HUVEC), and human coronary artery endothelial cells (HCAEC) exposed to TNF-α. Treatment with TNF-α downregulates the expression of miR-27b in all EC lines, promotes the activation of inflammatory pathways, induces mitochondrial alteration and reactive oxygen species accumulation, fostering the induction of intrinsic apoptosis. Moreover, miR-27b mimic counteracts the TNF-α-related cytotoxicity and inflammation, as well as cell cycle arrest and caspase-3-dependent apoptosis, restoring mitochondria redox state, function, and membrane polarization. Mechanistically, hsa-miR-27b-3p targets the 3′untranslated regions of FOXO1 mRNA to downregulate its expression, blunting the activation of the Akt/FOXO1 pathway. Here, we show that miR-27b is involved in the regulation of a broad range of functionally intertwined phenomena in EC, suggesting its key role in mitigating mithochondrial oxidative stress and inflammation, most likely through targeting of FOXO1. Overall, results reveal for the first time that miR-27b could represent a possible target for future therapies aimed at improving endothelial health.

In the context of nutrient-driven epigenetic alterations, food-derived miRNAs can be absorbed into the circulatory system and organs of recipients, especially humans, and potentially contribute to modulating health and diseases. Evidence suggests that food uptake, by carrying exogenous miRNAs (xenomiRNAs), regulates the individual miRNA profile, modifying the redox homeostasis and inflammatory conditions underlying pathological processes, such as type 2 diabetes mellitus, insulin resistance, metabolic syndrome, and cancer. The capacity of diet to control miRNA levels and the comprehension of the unique characteristics of dietary miRNAs in terms of gene expression regulation show important perspectives as a strategy to control disease susceptibility via epigenetic modifications and refine the clinical outcomes. However, the absorption, stability, availability, and epigenetic roles of dietary miRNAs are intriguing and currently the subject of intense debate; additionally, there is restricted knowledge of their physiological and potential side effects. Within this framework, we provided up-to-date and comprehensive knowledge on dietary miRNAs’ potential, discussing the latest advances and controversial issues related to the role of miRNAs in human health and disease as modulators of chronic syndromes.

Understanding the mechanisms of colorectal cancer progression is crucial in the setting of strategies for its prevention. δ-Valerobetaine (δVB) is an emerging dietary metabolite showing cytotoxic activity in colon cancer cells via autophagy and apoptosis. Here, we aimed to deepen current knowledge on the mechanism of δVB-induced colon cancer cell death by investigating the apoptotic cascade in colorectal adenocarcinoma SW480 and SW620 cells and evaluating the molecular players of mitochondrial dysfunction. Results indicated that δVB reduced cell viability in a time-dependent manner, reaching IC50 after 72 h of incubation with δVB 1.5 mM, and caused a G2/M cell cycle arrest with upregulation of cyclin A and cyclin B protein levels. The increased apoptotic cell rate occurred via caspase-3 activation with a concomitant loss in mitochondrial membrane potential and SIRT3 downregulation. Functional studies indicated that δVB activated mitochondrial apoptosis through PINK1/Parkin pathways, as upregulation of PINK1, Parkin, and LC3B protein levels was observed (p < 0.0001). Together, these findings support a critical role of PINK1/Parkin-mediated mitophagy in mitochondrial dysfunction and apoptosis induced by δVB in SW480 and SW620 colon cancer cells.

The relationship between dietary constituents and the onset and prevention of colorectal cancer (CRC) is constantly growing. Recently, the antineoplastic profiles of milk and whey from Mediterranean buffalo (Bubalus bubalis) have been brought to attention. However, to date, compared to cow milk, the potential health benefits of buffalo milk exosome-miRNA are still little explored. In the present study, we profiled the exosomal miRNA from buffalo milk and investigated the possible anticancer effects in CRC cells, HCT116, and HT-29. Results indicated that buffalo milk exosomes contained higher levels of miR-27b, miR-15b, and miR-148a compared to cow milk. Mimic miR-27b transfection in CRC cells induced higher cytotoxic effects (p < 0.01) compared to miR-15b and miR-148a. Moreover, miR-27b overexpression in HCT116 and HT-29 cells (miR-27b⁺) induced apoptosis, mitochondrial reactive oxygen species (ROS), and lysosome accumulation. Exposure of miR-27b⁺ cells to the bioactive 3kDa milk extract aggravated the apoptosis rate (p < 0.01), mitochondrial stress (p < 0.01), and advanced endoplasmic reticulum (ER) stress (p < 0.01), via PERK/IRE1/XBP1 and CHOP protein modulation (p < 0.01). Moreover, GSK2606414, the ER-inhibitor (ER-i), decreased the apoptosis phenomenon and XBP1 and CHOP modulation in miR-27b⁺ cells treated with milk (p < 0.01 vs. miR-27b⁺+Milk), suggesting the ER stress as a cell-death-aggravating mechanism. These results support the in vitro anticancer activity of 3kDa milk extract and unveil the contribution of miR-27b in the promising beneficial effect of buffalo milk in CRC prevention.

Betaines are food components widely distributed in plants, animals, microorganisms, and dietary sources. Among betaines, δ-valerobetaine (N,N,N-trimethyl-5-aminovaleric acid, δVB) shares a metabolic pathway common to γ-butyrobetaine (γBB). The biological properties of δVB are particularly attractive, as it possesses antioxidant, anti-inflammatory and anticancer activities. Here, we investigated the possible synergism between δVB and the structurally related γBB, to date unexplored, by testing the in vitro anticancer activity in head and neck squamous cell carcinoma cell lines, FaDu, UM-SCC-17A and Cal 27. Among cell lines tested, results indicated that betaines showed the highest effect in reducing Cal 27 cell proliferation up to 72 h (p < 0.01). This effect was enhanced when betaines were administered in combination (δVB plus γBB) (p < 0.001). Inhibition of cell growth by δVB plus γBB involved reactive oxygen species (ROS) accumulation, upregulation of sirtuin 1 (SIRT1), and apoptosis (p < 0.001). SIRT1 gene silencing by small interfering RNA decreased the apoptotic effect of δVB plus γBB by modulating downstream procaspase-3 and cyclin B1 (p < 0.05). These findings might have important implications for novel prevention strategies for tongue squamous cell carcinoma by targeting SIRT1 with naturally occurring betaines.

Ferroptosis, an iron-dependent form of cell death, and dysregulated microRNA (miRNA) expression correlate with colorectal cancer (CRC) development and progression. The tumor suppressor ability of miR-148a-3p has been reported for several cancers. Nevertheless, the role of miR-148a-3p in CRC remains largely undetermined. Here, we aim at investigating the molecular mechanisms and regulatory targets of miR-148a-3p in the CRC cell death mechanism(s). To this end, miR-148a-3p expression was evaluated in SW480 and SW620 cells and normal colon epithelial CCD 841 CoN cells with quantitative real-time polymerase chain reaction (qRT-PCR). Data reported a reduction of miR-148a-3p expression in SW480 and SW620 cells compared to non-tumor cells (p < 0.05). Overexpression of miR-148a selectively inhibited CRC cell viability (p < 0.001), while weakly affecting normal CCD 841 CoN cell survival (p < 0.05). At the cellular level, miR-148a-3p mimics promoted apoptotic cell death via caspase-3 activation (p < 0.001), accumulation of mitochondrial reactive oxygen species (ROS) (p < 0.001), and membrane depolarization (p < 0.001). Moreover, miR-148a-3p overexpression induced lipid peroxidation (p < 0.01), GPX4 downregulation (p < 0.01), and ferroptosis (p < 0.01), as revealed by intracellular and mitochondrial iron accumulation and ACSL4/TFRC/Ferritin modulation. In addition, levels of SLC7A11 mRNA and protein, the cellular targets of miR-148a-3p predicted by bioinformatic tools, were suppressed by miR-148a-3p’s overexpression. On the contrary, the downregulation of miR-148a-3p boosted SLC7A11 gene expression and suppressed ferroptosis. Together, these in vitro findings reveal that miR-148a-3p can function as a tumor suppressor in CRC by targeting SLC7A11 and activating ferroptosis, opening new perspectives for the rationale of therapeutic strategies through targeting the miR-148a-3p/SLC7A11 pathway.