1,2,3,4,6-penta-O-galloyl-beta-D-glucose attenuates renal cell migration, hyaluronan expression, and crystal adhesion

Thiouracil and triazole conjugate induces autophagy through the downregulation of Wnt/β-catenin signaling pathway in human breast cancer cells

Autophagy is vital for maintaining cellular homeostasis by breaking down unnecessary organelles and proteins within cells. Its activity varies abnormally in several diseases, including cancer, making it a potential target for therapeutic strategies. The Wnt/β-catenin signaling pathway significantly impacts cancer by stabilizing β-catenin protein and promoting the transcription of its target genes. Therefore, we aimed to identify candidate substances targeting this signaling pathway. We designed and tested a thiouracil conjugate, discovering that TTP-8 had anti-tumor effects on human breast cancer cell lines MCF-7 and MDA-MB231. Our findings showed that TTP-8 upregulated the expression of LC3 protein, a marker of autophagy in breast cancer cells, suggesting that TTP-8 might induce autophagy. Further analysis confirmed an increase in autophagy-related proteins, with consistent results obtained from flow cytometry and confocal microscopy. Interestingly, the induction of LC3 expression by TTP-8 was even more pronounced in MCF-7 and MDA-MB231 cells transfected with β-catenin siRNA. Thus, our research supports the idea that the Wnt/β-catenin signaling pathway influences the regulation of autophagy-related proteins, thereby inducing autophagy. This suggests that TTP-8 could serve as a novel agent for treating breast cancer.

Pentagalloyl Glucose: A Review of Anticancer Properties, Molecular Targets, Mechanisms of Action, Pharmacokinetics, and Safety Profile

Pentagalloyl glucose (PGG) is a natural hydrolyzable gallotannin abundant in various plants and herbs. It has a broad range of biological activities, specifically anticancer activities, and numerous molecular targets. Despite multiple studies available on the pharmacological action of PGG, the molecular mechanisms underlying the anticancer effects of PGG are unclear. Here, we have critically reviewed the natural sources of PGG, its anticancer properties, and underlying mechanisms of action. We found that multiple natural sources of PGG are available, and the existing production technology is sufficient to produce large quantities of the required product. Three plants (or their parts) with maximum PGG content were Rhus chinensis Mill, Bouea macrophylla seed, and Mangifera indica kernel. PGG acts on multiple molecular targets and signaling pathways associated with the hallmarks of cancer to inhibit growth, angiogenesis, and metastasis of several cancers. Moreover, PGG can enhance the efficacy of chemotherapy and radiotherapy by modulating various cancer-associated pathways. Therefore, PGG can be used for treating different human cancers; nevertheless, the data on the pharmacokinetics and safety profile of PGG are limited, and further studies are essential to define the clinical use of PGG in cancer therapies.

Interaction between nanometer calcium oxalate and renal epithelial cells repaired with carboxymethylated polysaccharides

OBJECTIVE

Injury of renal tubular epithelial cells (HK-2) is an important cause of kidney stone formation. In this article, the repairing effect of polysaccharide (PCP0) extracted from the traditional Chinese medicine Poria cocos and its carboxymethylated derivatives on damaged HK-2 cells was studied, and the differences in adhesion and endocytosis of the cells to nanometer calcium oxalate monohydrate (COM) before and after repair were explored.

METHODS

Sodium oxalate (2.8 mmol/L) was used to damage HK-2 cells to establish a damage model, and then Poria cocos polysaccharides (PCPs) with different carboxyl (COOH) contents were used to repair the damaged cells. The changes in the biochemical indicators of the cells before and after the repair and the changes in the ability to adhere to and internalize nano-COM were detected.

RESULTS

The natural PCPs (PCP0, COOH content = 2.56%) were carboxymethylated, and three carboxylated modified Poria cocos with 7.48% (PCP1), 12.07% (PCP2), and 17.18% (PCP3) COOH contents were obtained. PCPs could repair the damaged HK-2 cells, and the cell viability was enhanced after repair. The cell morphology was gradually repaired, the proliferation and healing rate were increased. The ROS production was reduced, and the polarity of the mitochondrial membrane potential was restored. The level of intracellular Ca²⁺ ions decreased, and the autophagy response was weakened.

CONCLUSION

The cells repaired by PCPs inhibited the adhesion to nano-COM and simultaneously promoted the endocytosis of nano-COM. The endocytic crystals mainly accumulated in the lysosome. Inhibiting adhesion and increasing endocytosis could reduce the nucleation, growth, and aggregation of cell surface crystals, thereby inhibiting the formation of kidney stones. With the increase of COOH content in PCPs, its ability to repair damaged cells, inhibit crystal adhesion, and promote crystal endocytosis all increased, that is, PCP3 with the highest COOH content showed the best ability to inhibit stone formation.

Degraded Porphyra yezoensis polysaccharide protects HK-2 cells and reduces nano-COM crystal toxicity, adhesion and endocytosis

We studied the protection of degraded Porphyra yezoensis polysaccharide (PYP) on human proximal tubular epithelial cells (HK-2) from cytotoxicity of nano-calcium oxalate monohydrate (COM) crystal, and the regulation of adhesion and endocytosis of the COM crystal. Four degraded fractions, namely, PYP1, PYP2, PYP3, and PYP4, were successfully obtained, with molecular weights (Mws) of 576.2, 49.5, 12.6, and 4.02 kDa, respectively. PYP protection reduced the crystal toxicity, prevented the destruction of cell morphology and cytoskeleton, inhibited the production of reactive oxygen species and the decline of lysosomal integrity, and reduced the expression of osteopontin and transmembrane protein (CD44). PYPi inhibited the adhesion and endocytosis of HK-2 cells by nano-COM. Endocytic COM crystals were accumulated in the lysosomes. With decreasing molecular weight, the ability of PYP to reduce cell damage and inhibit cell adhesion and endocytosis increased. PYP4, which has the smallest molecular weight, weaker intramolecular hydrogen bonds and more reducing groups, showed the best biological activity. PYPi can reduce the oxidative damage of the crystal to the cell, inhibit the adhesion and endocytosis of the crystal, and reduce the risk of kidney stone formation. Therefore, PYP, especially PYP4, has potential for use as a green drug to inhibit the formation and recurrence of calcium oxalate stones.

Protective Effects of Degraded Soybean Polysaccharides on Renal Epithelial Cells Exposed to Oxidative Damage

This study aimed to investigate the protective effects of degraded soybean polysaccharides (DSP) on oxidatively damaged African green monkey kidney epithelial (Vero) cells. Low DSP concentration (10 μg/mL) elicited an evident protective effect on H₂O₂-induced cell injury (0.3 mmol/L). The cell viabilities of the H₂O₂-treated group and the DSP-protected group were 57.3 and 93.1%, respectively. The cell viability decreased to 88.3% when the dosage was increased to 100 μg/mL. DSP protected Vero cells from H₂O₂-mediated oxidative damage by enhancing cellular superoxide dismutase activity and total antioxidant capacity and by decreasing malonaldehyde content and lactate dehydrogenase release. The H₂O₂-treated cells stimulated the aggregation of calcium oxalate monohydrate crystals. DSP could also reduce the crystal size, decrease the attached crystal content, and prevent the cell aggregation by alleviating oxidative injury and lipid peroxidation, enhancing antioxidant capacity, and decreasing hyaluronan expression on cellular surfaces. The internalization ability of the injured cells was improved after these cells were exposed to DSP solution. The regulation ability of DSP-repaired cells on calcium oxalate dihydrate formation, crystal attachment, aggregation, and internalization was lower than that of normal cells but was higher than that of the injured cells. DSP may be a potential green drug to prevent calcium oxalate (CaOx) stone formation because DSP could protect cells from oxidative damage and inhibit CaOx crystal formation.

Analgesic effects of 1,2,3,4,6-penta-O-galloyl-β-D-glucose in an animal model of lipopolysaccharide-induced pain

We examined the analgesic effects of 1,2,3, 4,6-penta-O-galloyl-β-D-glucose (β-PGG), a prototypical gallotannin, in an animal model of lipopolysaccharide (LPS)‑induced pain. To evaluate the analgesic activity of β-PGG, we assessed the potential of β-PGG to inhibit the generation of nitric oxide (NO) in LPS-stressed RAW 264.7 cells, and found that β-PGG inhibits NO generation in a dose-dependent manner. Furthermore, the effects of β-PGG on the voluntary movements of LPS-exposed animals were evaluated. The results showed that the voluntary movements of animals were markedly recovered after β-PGG treatment. The mRNA expression of interleukin (IL)-1β (1.33±0.38-fold) and IL-6 (0.64±0.40-fold) in the brain tissue of β-PGG-treated animals markedly decreased compared with that observed in the control groups (3.86±0.91 and 2.45±1.12-fold, respectively) and in the other LPS-administered groups. The results showed that β-PGG has potential to alleviate pain, not only by decreasing cellular NO generation in RAW 264.7 cells but also by the recovery of voluntary movement lost owing to inflammatory pain. This suggests that β-PGG is comparable to ibuprofen, which was used as a positive control in this study. Collectively, these findings suggest that β-PGG is a valuable natural compound which possesses analgesic activity.

Anti-nephrolithic potential of resveratrol via inhibition of ROS, MCP-1, hyaluronan and osteopontin in vitro and in vivo

BACKGROUND

Though resveratrol is known to have anti-cancer, anti-diabetic, anti-oxidant and anti-inflammatory activities, the inhibitory mechanism of resveratrol in kidney stone formation has not been elucidated so far.

METHOD

ELISA, flow cytometry, RT-PCR, and western blotting were performed. Human renal epithelial cells (HRCs) and rats with ethylene glycol (EG)-induced kidney stones were used.

RESULTS

A wound healing assay revealed that resveratrol significantly inhibited the oxalate-mediated migration of HRCs, considering oxalate mediates kidney stone formation. Also, resveratrol suppressed the mRNA expression of nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase subunits such as p22(phox) and p47(phox), monocyte chemoattractant protein 1 (MCP-1) and osteopontin (OPN) in oxalate-treated HRCs. Furthermore, western blotting showed that resveratrol downregulated the expression of MCP-1-related proteins including transforming growth factor(TGF-β1), TGFR-I or II and hyaluronan in oxalate-treated HRCs. Consistently, resveratrol reduced oxalate-mediated production of reactive oxygen species (ROS) and malondialdehyde (MDA) in oxalate-treated HRCs, while the activities of anti-oxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were enhanced by resveratrol in HRCs and EG-treated kidneys of rats. Consistently, resveratrol significantly reduced the number of urine calcium oxalate crystals and serum MDA, and attenuated the expression of OPN and hyaluroran in EG-treated rats.

CONCLUSIONS

Our findings suggest that resveratrol exerts anti-nephrolithic potential via inhibition of ROS, MCP-1 hyaluronan and OPN signaling.

Biological and biomedical functions of Penta-O-galloyl-D-glucose and its derivatives

Penta-O-galloyl-D-glucose (PGG) is a simple hydrolysable tannin in plants. PGG exists in two anomeric forms, α-PGG and β-PGG. While β-PGG can be found in a wide variety of plants, α-PGG is rather rare in nature. Numerous studies with β-PGG revealed a wide variety of biological activities, such as anti-microbial and anti-cancer functions. Until recently, studies with α-PGG were limited by the lack of its availability. Since the development of an efficient chemical synthesis of the compound, several investigations have revealed its anti-diabetic, anti-cancer, and anti-platelet-coagulation functions. Based on structure-activity-relationship (SAR) studies with α-PGG, a variety of α-PGG-related novel compounds were synthesized and some of them have been shown to possess promising therapeutic activities. In this review, the authors will survey and evaluate the biological functions of PGG with a focus on α-PGG and its derivatives.

Gallotannin suppresses calcium oxalate crystal binding and oxalate-induced oxidative stress in renal epithelial cells

Calcium oxalate monohydrate (COM) crystals bind avidly to the surface of proliferating and migrating renal endothelial cells, perhaps a key event in kidney stone formation. Oxalate-induced pre-oxidative stress can further promote crystal attachment cells. Natural products including gallotannins found in green teas have been studied as potentially novel treatments to prevent crystal retention and kidney stone formation. Gallotannin significantly inhibited COM crystal growth and binding to Madin-Darby Canine Kidney Cells type I (MDCK I) renal epithelial cells at non-toxic concentrations. Reverse transcription polymerase chain reaction (RT-PCR) analysis revealed that gallotannin significantly attenuated oxalate-induced mRNA and protein expressions of monocyte chemoattractant protein 1 (MCP-1), osteopontin (OPN), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit p22(phox) and p47(phox) in human primary renal epithelial cells (HRCs). Gallotannin also reduced the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) as well as enhanced antioxidant enzyme superoxide dismutase (SOD) activity in oxalate treated HRCs. Taken together, our findings suggest that gallotannin can contribute to nephrolithiasis prevention via direct effects on renal epithelial cells including suppression of COM binding and MCP-1 and OPN expression, along with augmenting antioxidant activity.

The genome-wide expression profile of 1,2,3,4,6-penta-O-galloyl-β-D-glucose-treated MDA-MB-231 breast cancer cells: molecular target on cancer metabolism

1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG), a polyphenolic compound isolated from Rhus chinensis Mill. PGG has been known to have anti-tumor, anti-angiogenic and anti-diabetic activities. The present study revealed another underlying molecular target of PGG in MDA-MB-231 breast cancer cells by using Illumina Human Ref-8 expression BeadChip assay. Through the Beadstudio v3 micro assay program to compare the identified genes expressed in PGG-treated MDA-MB-231 cells with untreated control, we found several unique genes that are closely associated with pyruvate metabolism, glycolysis/gluconeogenesis and tyrosine metabolism, including PC, ACSS2, ACACA, ACYP2, ALDH3B1, FBP1, PRMT2 and COMT. Consistent with microarray data, real-time RT-PCR confirmed the significant down-regulation of these genes at mRNA level in PGG-treated MDA-MB-231 cells. Our findings suggest the potential of PGG as anticancer agent for breast cancer cells by targeting cancer metabolism genes.

1,2,3,4,6-Penta-O-galloyl-beta-D-glucose reduces renal crystallization and oxidative stress in a hyperoxaluric rat model

Adhesion of calcium oxalate (CaOx) crystals to kidney cells may be a key event in the pathogenesis of kidney stones associated with marked hyperoxaluria. Previously, we found that 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), isolated from a traditional medicinal herb, reduced CaOx crystal adhesion to renal epithelial cells by acting on the cells as well as on the crystal surface. Here we used the ethylene glycol (EG)-mediated hyperoxaluric rat model and found evidence of oxidant stress as indicated by decreases in the activities of the renal antioxidant enzymes, superoxide dismutase, catalase, and glutathione peroxidase, with increased kidney cell apoptosis and serum malondialdehyde levels, all evident by 21 days of EG treatment. These effects of hyperoxaluria were reversed by concurrent PGG treatment along with decreased urinary oxalate levels and CaOx supersaturation. Renal epithelial cell expression of the crystal binding molecule hyaluronan increased diffusely within 7 days of EG initiation, suggesting it is not a result of but precedes crystal deposition. Renal cell osteopontin (OPN) was also upregulated in EG-treated animals, and PGG significantly attenuated overexpression of both OPN and hyaluronan. Thus, our findings demonstrate that PGG reduces renal crystallization and oxidative renal cell injury, and may be a candidate chemopreventive agent for nephrolithiasis.

Oxidative renal cell injury induced by calcium oxalate crystal and renoprotection with antioxidants: a possible role of oxidative stress in nephrolithiasis

PURPOSE

Calcium oxalate (CaOx) is one of the key elements for kidney stone formation, but the exact mechanism needs to be defined. CaOx has been shown to cause renal cell injury through oxidative stress, leading to potential crystal deposition in the kidneys. We thus investigated if CaOx crystal would induce such renal cell injury in vitro and also explored how it would be carried out.

MATERIALS AND METHODS

Renal tubular epithelial LLC-PK(1) cells were employed, and CaOx monohydrate (COM) was used as CaOx crystal in this study. Cytotoxic effects of COM were assessed on cell viability and biochemical parameters, while protective effect of antioxidants against COM was also examined.

RESULTS

COM demonstrated its cytotoxicity on LLC-PK(1) cells, exhibiting a approximately 35% cell viability reduction with 500 microg/mL COM in 6 hours. This was presumably attributed to oxidative stress, indicated by lipid peroxidation assay, and N-acetylcysteine (NAC), a potent antioxidant, indeed neutralized such COM cytotoxicity. Although COM also induced inactivation of glutathione-dependent enzymes and partial degradation of heat shock protein 90, these adverse effects were completely prevented with NAC. Moreover, such reduced cell viability with COM was rather associated with apoptosis, evidenced by DNA analysis.

CONCLUSION

COM is cytotoxic to LLC-PK(1) cells through oxidative stress, leading to the cell viability reduction, adverse effects on biochemical parameters, and, consequently, apoptosis. However, NAC effectively averted such severe cytotoxic effects, sustaining the renal cell integrity. Thus, NAC may provide full renoprotection against COM assault, preventing renal cell injury and ultimate stone formation.

Anti-cancer, anti-diabetic and other pharmacologic and biological activities of penta-galloyl-glucose

1, 2, 3, 4, 6-penta-O-galloyl-beta-D-glucose (PGG) is a polyphenolic compound highly enriched in a number of medicinal herbals. Several in vitro and a handful of in vivo studies have shown that PGG exhibits multiple biological activities which implicate a great potential for PGG in the therapy and prevention of several major diseases including cancer and diabetes. Chemically and functionally, PGG appears to be distinct from its constituent gallic acid or tea polyphenols. For anti-cancer activity, three published in vivo preclinical cancer model studies with PGG support promising efficacy to selectively inhibit malignancy without host toxicity. Potential mechanisms include anti-angiogenesis; anti-proliferative actions through inhibition of DNA replicative synthesis, S-phase arrest, and G(1) arrest; induction of apoptosis; anti-inflammation; and anti-oxidation. Putative molecular targets include p53, Stat3, Cox-2, VEGFR1, AP-1, SP-1, Nrf-2, and MMP-9. For anti-diabetic activity, PGG and analogues appear to improve glucose uptake. However, very little is known about the absorption, pharmacokinetics, and metabolism of PGG, or its toxicity profile. The lack of a large quantity of highly pure PGG has been a bottleneck limiting in vivo validation of cancer preventive and therapeutic efficacies in clinically relevant models.