Evaluation of the correlation between focal adhesion kinase phosphorylation and cell adhesion force using "DEP" technology

Amygdalin: A Review on Its Characteristics, Antioxidant Potential, Gastrointestinal Microbiota Intervention, Anticancer Therapeutic and Mechanisms, Toxicity, and Encapsulation

Bioactive amygdalin, found in high concentrations in bitter almonds, has been recognized as a symbol of the cyanogenic glycoside chemical organic substance, which was initially developed as a pharmaceutical for treating cancer after being hydrolyzed to hydrogen cyanide (HCN). Regrettably, research has shown that HCN can also damage normal cells, rendering it non-toxic to the human body. Extreme controversy surrounds both in vivo and in vitro studies, making its use risky. This review provides an extensive update on characteristics, antioxidant potential, gastrointestinal microbiota intervention, anticancer therapeutic, mechanisms, toxicity, and encapsulation of amygdalin. Antioxidant, anti-tumor, anti-fibrotic, antiatherosclerosis, anti-inflammatory, immunomodulatory, and analgesic characteristics, and the ability to improve digestive and reproductive systems, neurodegeneration, and cardiac hypertrophy are just some of the benefits of amygdalin. Studies verified the HCN-produced amygdalin to be harmful orally, but only at very high doses. Although intravenous treatment was less effective than the oral method, the oral route has a dose range of 0.6 to 1 g daily. Amygdalin’s toxicity depends heavily on the variety of bacteria in the digestive tract. Unfortunately, there is currently no foolproof method for determining the microbial consortium and providing a safe oral dosage for every patient. Amygdalin encapsulation in alginate-chitosan nanoparticles (ACNPs) is a relatively new area of research. Amygdalin has an enhanced cytotoxic effect on malignant cells, and ACNPs can be employed as an active drug-delivery system to release this compound in a regulated, sustained manner without causing any harm to healthy cells or tissues. In conclusion, a large area of research for a substance that might be the next step in cancer therapy is opened up due to unverified and conflicting data.

Amygdalin - A pharmacological and toxicological review

ETHNOPHARMACOLOGICAL RELEVANCE

Amygdalin is commonly distributed in plants of the Rosaceae, such as peach, plum, loquat, apple and bayberry, but most notably in the seeds (kernels) of apricot almonds. As a naturally aromatic cyanogenic compound, it has long been used in Asia, Europe and other regions for the treatment of various diseases including cough, asthma, nausea, leprosy and leukoderma. Importantly, in recent years, an increasing attention has been paid to its antitumor effect.

AIM OF THE STUDY

The paper aims to review the pharmacological activities and toxicological effects of amygdalin and provide a reference and perspective for its further investigation.

METHODS

Electronic databases including the Web of Science, Cochrane Library, PubMed, EMBASE, the Chinese Biological Medicine Database, China National Knowledge Infrastructure, Wanfang database and VIP information database were searched up to November 2019 to identify eligible studies. A meticulous review was performed, an in-depth analysis on the pharmacological activity and toxicology of amygdalin was conducted, and perspectives for future research were also discussed.

RESULTS

A total of 110 papers about in vitro/in vivo studies on amygdalin have been reviewed. Analysis on the data suggested that this compound presented pharmacological activities of anti-tumor, anti-fibrotic, anti-inflammatory, analgesic, immunomodulatory, anti-atherosclerosis, ameliorating digestive system and reproductive system, improving neurodegeneration and myocardial hypertrophy, as well as reducing blood glucose. In addition, studies revealed that amygdalin's toxicity was caused by its poisonous decomposite product of benzaldehyde and hydrogen cyanide after oral ingestion, toxicity of intravenous administration route was far less than the oral route, and it can be avoidable with an oral dose ranging from 0.6 to 1 g per day.

CONCLUSION

This paper has systematically reviewed the pharmacology and toxicology of amygdalin and provided comprehensive information on this compound. We hope this review highlights some perspectives for the future research and development of amygdalin.

Dermal Lipogenesis Inhibits Adiponectin Production in Human Dermal Fibroblasts while Exogenous Adiponectin Administration Prevents against UVA-Induced Dermal Matrix Degradation in Human Skin

Adiponectin is one of the most abundant adipokines from the subcutaneous fat, and regulates multiple activities through endocrine, paracrine, or autocrine mechanisms. However, its expression in adipogenic induced fibroblasts, and the potential role in photoaging has not been determined. Here, human dermal fibroblasts, Hs68, were presented as a cell model of dermal lipogenesis through stimulation of adipogenic differentiation medium (ADM). Similar to other studies in murine pre-adipocyte models (i.e., 3T3-L1), Hs68 fibroblasts showed a tendency to lipogenesis based on lipid accumulation, triglyceride formation, and the expressions of PPAR-γ, lipoprotein lipase (LPL), and FABP4 mRNA. As expected, ADM-treated fibroblasts displayed a reduction on adiponectin expression. Next, we emphasized the photoprotective effects of adiponectin against UVA-induced damage in Hs68 fibroblasts. UVA radiation can downregulate cell adhesion strength and elastic modulus of Hs68 fibroblasts. Moreover, UVA radiation could induce the mRNA expressions of epidermal growth factor receptor (EGFR), adiponectin receptor 1 (AdipoR1), matrix metalloproteinase-1 (MMP-1), MMP-3, and cyclooxygenase-2 (COX-2), but downregulate the mRNA expressions of type I and type III collagen. On the other hand, post-treatment of adiponectin can partially overcome UVA-induced reduction in the cell adhesion strength of Hs68 fibroblasts through the activation of AdipoR1 and the suppression of EGF-R. In addition, post-treatment of adiponectin indicated the increase of type III collagen and elastin mRNA expression and the decrease of MMP-1 and MMP-3 mRNA expression, but a limited degree of recovery of elastic modulus on UVA-irradiated Hs68 fibroblasts. Overall, these results suggest that dermal lipogenesis may inhibit the expression of adiponectin while exogenous adiponectin administration prevents against UVA-induced dermal matrix degradation in Hs68 fibroblasts.

Amygdalin influences bladder cancer cell adhesion and invasion in vitro

The cyanogenic diglucoside amygdalin, derived from Rosaceae kernels, is employed by many patients as an alternative anti-cancer treatment. However, whether amygdalin indeed acts as an anti-tumor agent is not clear. Metastasis blocking properties of amygdalin on bladder cancer cell lines was, therefore, investigated. Amygdalin (10 mg/ml) was applied to UMUC-3, TCCSUP or RT112 bladder cancer cells for 24 h or for 2 weeks. Tumor cell adhesion to vascular endothelium or to immobilized collagen as well as tumor cell migration was examined. Effects of drug treatment on integrin α and β subtypes, on integrin-linked kinase (ILK) and total and activated focal adhesion kinase (FAK) were also determined. Integrin knock-down was carried out to evaluate integrin influence on migration and adhesion. A 24 h or 2 week amygdalin application distinctly reduced tumor cell adhesion and migration of UMUC-3 and RT112 cells. TCCSUP adhesion was also reduced, but migration was elevated under amygdalin. Integrin subtype expression was significantly and specifically altered by amygdalin depending on the cell line. ILK was moderately, and activated FAK strongly, lost in all tumor cell lines in the presence of amygdalin. Knock down of β1 integrin caused a significant decrease in both adhesion and migration of UMUC-3 cells, but a significant increase in TCCSUP adhesion. Knock down of β4 integrin caused a significant decrease in migration of RT112 cells. Since the different actions of amygdalin on the different cell lines was mirrored by β1 or β4 knock down, it is postulated that amygdalin influences adhesion and migratory properties of bladder cancer cells by modulating β1 or β4 integrin expression. The amygdalin induced increase in TCCSUP migratory behavior indicates that any anti-tumor benefits from amygdalin (seen with the other two cell lines) may depend upon the cancer cell type.

Down-regulation of integrin β1 and focal adhesion kinase in renal glomeruli under various hemodynamic conditions

Given that integrin β1 is an important component of the connection to maintain glomerular structural integrity, by binding with multiple extracellular matrix proteins and mediating intracellular signaling. Focal adhesion kinase (FAK) is the most essential intracellular integrator in the integrin β1-FAK signalling pathway. Here, we investigated the changes of the two molecules and visualized the possbile interaction between them under various hemodynamic conditions in podocytes. Mice kidney tissues were prepared using in vivo cryotechnique (IVCT) and then were stained and observed using light microscopy, confocal laser scanning microscopy and immunoelectron microscopy. The expression of these molecules were examined by western blot. Under the normal condition, integrin β1 stained continually and evenly at the membrane, and FAK was located in the cytoplasm and nuclei of the podocytes. There were significant colocalized plaques of two molecules. But under acute hypertensive and cardiac arrest conditions, integrin β1 decreased and stained intermittently. Similarly, FAK decreased and appeared uneven. Additionally, FAK translocated to the nuclei of the podocytes. As a result, the colocalization of integrin β1 and FAK reduced obviously under these conditions. Western blot assay showed a consistent result with the immunostaining. Collectively, the abnormal redistribution and decreased expressions of integrin β1 and FAK are important molecular events in regulating the functions of podocytes under abnormal hemodynamic conditions. IVCT could offer considerable advantages for morphological analysis when researching renal diseases.