An in vitro investigation of the effects of urolithins A and B on low-density lipoprotein uptake and its regulatory genes.

Introduction: This study aimed to evaluate the possible role of urolithin A (UA) and urolithin B (UB) on the mRNA expression levels of LDL receptor (LDLR) and PSCK9 genes, and also of the uptake of LDL particles in HepG2 cells. Material and methods: The potential role of UA and UB on the induction of LDL uptake and the expression of its regulatory genes was explored using HepG2 cells and curcumin (20 µM), berberine (50 µM), UA (80 µM), and UB (80 µM) as the treatments in the experimental tests. Results: The LDL uptake and cell-surface LDLR were higher in cells treated with UA in comparison with cells treated with UB, and even in relation to the cells treated with curcumin and berberine as positive controls. In addition, cells treated with UB showed approximately 2 times greater LDLR expression levels compared with curcumin (FC = 2.144, p = 0.013) and berberine (FC = 2.761, p = 0.006). However, UA treatment resulted in significantly lower expression levels of LDLR compared with curcumin (FC = 0.274, p < 0.001) and berberine (FC = 0.352, p = 0.009). UB demonstrated approximately 8 times higher LDLR expression levels when compared with UA (FC = 7.835, p = 0.001). Compared with UB, as well as curcumin and berberine as positive controls, UA was more efficient in reducing PCSK9 expression levels. Although UB did not show any significant differences compared with curcumin and berberine, it showed higher levels of PCSK9 expression when compared with the UA group (FC = 3.694, p < 0.001). Conclusions: The present results suggest that UA was more effective than UB in promoting LDL uptake as well as cell surface LDLR in HepG2 cells. This effect seems to be mostly mediated through the suppression of PCSK9 expression but not the induction of LDLR expression.

Analysis of Cytotoxic Effects of Zerumbone in Malignant Glioblastoma Cells.

Glioblastoma multiforme (GBM) is an aggressive tumor in the central nervous system with a poor prognosis. Currently, the main interventions include surgery, chemotherapy, and radiotherapy. Recently, several natural products have been reported as potentially effective and safer treatment options. Here, we studied the effects of zerumbone, a sesquiterpene compound derived from Zingiber zerumbet Smith rhizomes, on human GBM U-87 MG cells in vitro. To meet this purpose, we used a cytotoxicity assay, as well as a quantitative polymerase chain reaction of apoptosis-related genes and western blot analysis of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), a transcription factor that controls the production of cytokines and molecules involved in cell survival.

Impact of Curcumin on Hepatic Low-Density Lipoprotein Uptake.

Elevated levels of plasma low-density lipoprotein cholesterol (LDL-C) are causally related to atherosclerotic cardiovascular disease. Enhancing the removal of LDL particles from the plasma, mainly by the liver, is the most efficient strategy for reducing LDL-C and the ensuing atherosclerosis. In this context, polyphenolic compounds like curcumin have generated interest owing to their lipid-modifying capacity. The promising effect of curcumin has been studied in attenuating atherosclerosis (in experimental models), and correcting dyslipidemia (in clinical studies). The underlying mechanisms of the effects of curcumin are relatively unknown, and the impact of curcumin on hepatic LDL uptake warrants further investigations. Here, we present a protocol to assess the effects of curcumin on LDL uptake in hepatocytes.

PCSK9 and cancer: Rethinking the link.

BACKGROUND: Cancer is emerging as a major problem globally, as it accounts for the second cause of death despite medical advances. According to epidemiological and basic studies, cholesterol is involved in cancer progression and there are abnormalities in cholesterol metabolism of cancer cells including prostate, breast, and colorectal carcinomas. However, the importance of cholesterol in carcinogenesis and thereby the role of cholesterol homeostasis as a therapeutic target is still a debated area in cancer therapy. Proprotein convertase subtilisin/kexin type-9 (PCSK9), a serine protease, modulates cholesterol metabolism by attachment to the LDL receptor (LDLR) and reducing its recycling by targeting the receptor for lysosomal destruction. Published research has shown that PCSK9 is also involved in degradation of other LDLR family members namely very-low-density-lipoprotein receptor (VLDLR), lipoprotein receptor-related protein 1 (LRP-1), and apolipoprotein E receptor 2 (ApoER2). As a result, this protein represents an interesting therapeutic target for the treatment of hypercholesterolemia. Interestingly, clinical trials on PCSK9-specific monoclonal antibodies have reported promising results with high efficacy in lowering LDL-C and in turn reducing cardiovascular complications. It is important to note that PCSK9 mediates several other pathways apart from its role in lipid homeostasis, including antiviral activity, hepatic regeneration, neuronal apoptosis, and modulation of various signaling pathways. Furthermore, recent literature has illustrated that PCSK9 is closely associated with incidence and progression of several cancers. In a number of studies, PCSK9 siRNA was shown to effectively suppress the proliferation and invasion of the several studied tumor cells. Hence, a novel application of PCSK9 inhibitors/silencers in cancer/metastasis could be considered. However, due to poor data on effectiveness and safety of PCSK9 inhibitors in cancer, the impact of PCSK9 inhibition in these pathological conditions is still unknown. SEARCH METHODS: A vast literature search was conducted to find intended studies from 1956 up to 2020, and inclusion criteria were original peer-reviewed publications. PURPOSE OF REVIEW: To date, PCSK9 has been scantly investigated in cancer. The question that needs to be discussed is "How does PCSK9 act in cancer pathophysiology and what are the risks or benefits associated to its inhibition?". We reviewed the available publications highlighting the contribution of this proprotein convertase in pathways related to cancer, with focus on the potential implications of its long-term pharmacological inhibition in cancer therapy.

UiO-66 metal organic framework nanoparticles loaded carboxymethyl chitosan/poly ethylene oxide/polyurethane core-shell nanofibers for controlled release of doxorubicin and folic acid.

Doxorubicin (DOX) and folic acid (FA) were incorporated into the UiO-66 metal organic framework (MOF) and following were loaded into the carboxymethyl chitosan/poly ethylene oxide (PEO)/polyurethane core-shell nanofibers for controlled release of DOX and FA toward MCF-7 cells death. The synthesized nanocarriers were characterized using TEM, XRD, and SEM analysis. The drug loading efficiency and release profiles of DOX/MOF and FA/MOF from synthesized nanofibers have been investigated. The fitting of kinetic data by the pharmacokinetic models demonstrated the non-Fickian diffusion from nanofibers and Fickian diffusion from core-shell fibers. The cytotoxicity of synthesized nanofibers toward MCF-7 cancer cells was evaluated using DAPI staining, MTT assay and flow cytometry tests to investigate the simultaneous use of DOX and FA in the nanofibrous matrix for MCF-7 cells death in vitro. The maximum cell death using DOX-FA loaded-core-shell fibers produced by coaxial electrospinning method under 0.3, 0.5 and 0.8 mLh-1 shell flow rates were found to be 82 ± 0.7, 83 ± 0.5 and 87 ± 0.5% after 168, 240 and 240 h, respectively. The cytotoxicity results indicated that the co-delivery of DOX and FA into the core-shell fibers could be widely used for various cancers treatment.

Simultaneous controlled release of 5-FU, DOX and PTX from chitosan/PLA/5-FU/g-C3N4-DOX/g-C3N4-PTX triaxial nanofibers for breast cancer treatment in vitro.

In the present study, the tri-layer nanofibers were synthesized via triaxial electrospinning process to control the sustained delivery of Doxorubicin (DOX), Paclitaxel (PTX) and 5- fluorouracil (5-FU) anticancer drugs from nanofibers. The 5-FU molecules were incorporated into the core solution (chitosan/polyvinyl alcohol (CS/PVA)) to fabricate the CS/PVA/5-FU inner layer of nanofibers. The intermediate layer was prepared from poly(lactic acid)/chitosan (PLA/CS) nanofibers. The DOX and PTX molecules were initially loaded into the g-C3N4 nanosheets and following were incorporated into the PLA/CS solution to fabricate the outer layer of nanofibers. The synthesized nanosheets and nanofibers were characterized using XRD, SEM, TEM and UV-vis analysis. The PLA/PVA/CS/FU/g-C3N4/DOX/PTX single layer nanofibers were also synthesized via electrospinning method. The drug loading efficiency, degradation rate and anticancer drugs release profiles from single layer and tri-layer nanofibers were investigated under various intermediate and shell layer thicknesses. The pharmacokinetic studies were performed to understand the drugs release mechanism from nanofibers. The cell viability and cell attachment of drug loaded single layer and tri-layer nanofibers toward the MCF-7 breast cancer cells were examined to achieve an optimum nanofibrous formulation for the breast cancer treatment. The obtained results revealed the high activity of tri-layer nanofibers for the breast cancer cells killing.

Effects of palmitate and astaxanthin on cell viability and proinflammatory characteristics of mesenchymal stem cells.

Mesenchymal stem cells (MSCs) have broad immunomodulatory activities. These cells are a stable source of cytokine production such as interleukin-6 (IL6), monocyte chemoattractant protein-1 (MCP-1/CCL2) and vascular endothelial growth factor (VEGF). Fatty acid elevation in chronic metabolic diseases alters the microenvironment of MSCs and thereby, might affect their survival and cytokine production. In the present study, we investigated the effects of palmitate, the most abundant saturated free fatty acid (FFA) in plasma, and astaxanthin, a potent antioxidant, on cell viability and apoptosis in human bone marrow-driven mesenchymal stem cells. We also elucidated how palmitate and astaxanthin influence the inflammation in MSCs. Human mesenchymal stem cells were collected from an aspirate of the femurs and tibias marrow compartment. The effect of palmitate on cell viability, caspase activity and pro-inflammatory cytokines expression and secretion were evaluated. In addition, activation of the MAP kinases and NF-kB signaling pathways were investigated. The results showed that astaxanthin protected MSCs from palmitate-induced cell death. We found that palmitate significantly enhanced IL-6, VEGF and MCP-1 expression, and secretion in MSC cells. Increased cytokine expression was parallel to the enhanced phosphorylation of P38, ERK and IKKα-IKKß. In addition, pretreatment with JNK, ERK, P38, and NF-kB inhibitors could correspondingly attenuate palmitate-induced expression of VEGF, IL-6, and MCP-1. Our results demonstrated that fatty acid exposure causes inflammatory responses in MSCs that can be alleviated favorably by astaxanthin treatment.