Procyanidins, from Castanea mollissima Bl. shell, induces autophagy following apoptosis associated with PI3K/AKT/mTOR inhibition in HepG2 cells

Proanthocyanidin enhances the endogenous regeneration of alveolar bone by elevating the autophagy of PDLSCs

OBJECTIVE

This study aimed to investigate the effect of proanthocyanidin (PA) on osteogenesis mediated by periodontal ligament stem cells (PDLSCs) and endogenous alveolar bone regeneration.

BACKGROUND

Leveraging the osteogenic potential of resident stem cells is a promising strategy for alveolar bone regeneration. PA has been reported to be effective in osteogenesis. However, the effect and mechanism of PA on the osteogenic differentiation of PDLSCs remain elusive.

METHODS

Human PDLSCs were treated with various doses of PA to assess the cell proliferation using Cell Counting Kit-8. The osteogenic differentiation ability was detected by qRT-PCR analysis, western blot analysis, Alizarin red S staining, and Alkaline Phosphatase staining. The level of autophagy was evaluated by confocal laser scanning microscopy, transmission electron microscopy, and western blot analysis. RNA sequencing was utilized to screen the potential signaling pathway. The alveolar bone defect model of rats was created to observe endogenous bone regeneration.

RESULTS

PA activated intracellular autophagy in PDLSCs, resulting in enhanced osteogenic differentiation. Moreover, this effect could be abolished by the autophagy inhibitor 3-Methyladenine. Mechanistically, the PI3K/Akt/mTOR pathway was negatively correlated with PA-mediated autophagy activation. Lastly, PA promoted the alveolar bone regeneration in vivo, and this effect was reversed when the autophagy process was blocked.

CONCLUSION

PA may activate autophagy by inhibiting PI3K/Akt/mTOR signaling pathway to promote the osteogenesis of PDLSCs and enhance endogenous alveolar bone regeneration.

How autophagy, a potential therapeutic target, regulates intestinal inflammation

Inflammatory bowel disease (IBD) is a group of disorders that cause chronic inflammation in the intestines, with the primary types including ulcerative colitis and Crohn's disease. The link between autophagy, a catabolic mechanism in which cells clear protein aggregates and damaged organelles, and intestinal health has been widely studied. Experimental animal studies and human clinical studies have revealed that autophagy is pivotal for intestinal homeostasis maintenance, gut ecology regulation and other aspects. However, few articles have summarized and discussed the pathways by which autophagy improves or exacerbates IBD. Here, we review how autophagy alleviates IBD through the specific genes (e.g., ATG16L1, IRGM, NOD2 and LRRK2), crosstalk of multiple phenotypes with autophagy (e.g., Interaction of autophagy with endoplasmic reticulum stress, intestinal antimicrobial defense and apoptosis) and autophagy-associated signaling pathways. Moreover, we briefly discuss the role of autophagy in colorectal cancer and current status of autophagy-based drug research for IBD. It should be emphasized that autophagy has cell-specific and environment-specific effects on the gut. One of the problems of IBD research is to understand how autophagy plays a role in intestinal tract under specific environmental factors. A better understanding of the mechanism of autophagy in the occurrence and progression of IBD will provide references for the development of therapeutic drugs and disease management for IBD in the future.

An icaritin-loaded microemulsion based on coix oil for improved pharmacokinetics and enhanced antitumor efficacy

Combinational icaritin (IC) and coix seed oil (CSO) holds promising potential in the treatment of hepatocellular carcinoma. However, traditional cocktail therapy is facing difficulties to optimize the synergistic antitumor efficacy due to the asynchronous pharmacokinetics. Therefore, we developed an icaritin-loaded microemulsion based on coix seed oil (IC-MEs) for improved pharmacokinetics and enhanced antitumor efficacy. The preparation technology of IC-MEs was optimized by the Box-Behnken design and the pharmaceutical properties were characterized in detail. IC-MEs show synergistic antiproliferation against HepG2 cells compared with monotherapy. The mechanism is associated with stronger apoptosis induction via enhancing caspases-3 activity. IC-MEs significantly improve the bioavailability of IC due to the encapsulation of coix oil-based microemulsion and also obtain the desired liver accumulation and elimination. More importantly, IC-MEs exhibit the overwhelming antitumor ability among all of the treatments on the HepG2 xenograft-bearing mice. This study verifies the feasibility of using coix oil-based microemulsion to improve the antitumor effect of water-insoluble components.

Metabolic Profiling of Chestnut Shell (Castanea crenata) Cultivars Using UPLC-QTOF-MS and Their Antioxidant Capacity

The inner shell of the chestnut (Castanea crenata) has long been used in Asia as a medicinal herb for improving digestion and blood circulation, and treating diarrhea. However, most chestnut shells are now treated as waste materials in industrial peeling processes. In this study, we examined the metabolite variation among major cultivars of C. crenata shells using mass spectrometry. Among five representative cultivars, Okkwang, Porotan, and Ishizuuchi had higher levels of bioactive compounds, such as ellagic acid derivatives, ellagitannins, flavonoids, and gallic acid derivatives. Their antioxidant capacity was positively correlated with their chemical composition. The byproducts (whole shells) from the industrial peeling process were re-evaluated in comparison with the inner shell, a rich source of phenolic compounds. The phenolic acids and flavonoid glucoside derivatives were significantly higher in the whole shells, whereas the levels of flavonoids were higher in the inner shells. In addition, the whole shell extracts significantly reduced cellular reactive oxygen species production compared to the inner shell extracts. This study demonstrated the different biochemical benefits of different C. crenata cultivars through metabolic profiling and suggests that the whole shell could be used as a functional ingredient, as it has the highest levels of bioactive products and antioxidant effects.

Procyanidin A1 alleviates DSS-induced ulcerative colitis via regulating AMPK/mTOR/p70S6K-mediated autophagy

Ulcerative colitis (UC) is a recurrent chronic inflammatory disease. The symptom of UC is mainly diarrhea including bloody stools. Increasing evidence has suggested that procyanidin A1 (PCA1) exerts an anti-inflammatory effect in several diseases. However, the role of PCA1 in UC is still a mystery. In our study, we explored the effect of PCA1 in dextran sulfate sodium (DSS)-induced UC mice and lipopolysaccharide (LPS)-stimulated HT-29 and IEC-6 cells. Then, cell proliferation, apoptosis, the production of proinflammatory cytokines, and autophagy-related markers were determined. Furthermore, the AMPK/mTOR/p70S6K signaling pathway was assayed by Western blot assay. In in vivo study, we found that PCA1 administration alleviated DSS-induced UC, as evidenced by reducing weight loss, clinical scores, colon weight/length ratio, histological damage, proinflammatory cytokines, and apoptosis. Moreover, we showed that the expression of Beclin-1 and LC3II/I ratio was increased, whereas the level of p62 was decreased after PCA1 treatment in vivo. Meanwhile, the reduced AMP/ATP ratio, enhanced expression of p-AMPK, and decreased p-p70S6K and p-mTOR levels indicate the activation of AMPK/mTOR/p70S6K signaling pathway. In in vitro study, PCA1 promoted cell proliferation and inhibited cell apoptosis in LPS-stimulated HT-29 and IEC-6 cells. Pro-inflammatory cytokines and autophagy-related factors exhibited the same trend as in in vivo results. Mechanically, PCA1 activated the AMPK/mTOR/p70S6K signaling pathway. The treatment with an AMPK inhibitor compound C significantly reversed the anti-inflammatory effect of PCA1 in LPS-stimulated cells. Taken together, these data indicated that PCA1 alleviated UC through induction of AMPK/mTOR/p70S6K-mediated autophagy.

Co-delivery of proanthocyanidin and mitoxantrone induce synergistic immunogenic cell death to potentiate cancer immunotherapy

Immunological checkpoint inhibitors provide a revolutionary method for cancer treatment. However, due to low tumor mutations and insufficient infiltration of immune cells in the tumor microenvironment, 85% of colorectal cancer...

Procyanidin B2 alleviates liver injury caused by cold stimulation through Sonic hedgehog signalling and autophagy

Procyanidin B2 (PB2), a naturally occurring flavonoid abundant in a wide range of fruits, has been shown to exert antioxidant, anti‐inflammatory and anticancer properties. However, the role of PB2 in the prevention of cold stimulation (CS)‐induced liver injury. The present study was undertaken to determine the effects of PB2 on liver injury induced by cold stimulation and its potential molecular mechanisms. The present study results showed that treatment with PB2 significantly reduced CS‐induced liver injury by alleviating histopathological changes and serum levels of alanine transaminase and aspartate transaminase. Moreover, treatment with PB2 inhibited secretion of inflammatory cytokines and oxidative stress in cold‐stimulated mice. PB2 reduced cold stimulation‐induced inflammation by inhibiting TLR4/NF‐κB and Txnip/NLRP3 signalling. Treatment with PB2 reduced oxidative stress by activating Nrf‐2/Keap1, AMPK/GSK3β signalling pathways and autophagy. Furthermore, simultaneous application of Shh pathway inhibitor cyclopamine proved that PB2 targets the Hh pathway. More importantly, co‐treatment with PB2 and cyclopamine showed better efficacy than monotherapy. In conclusion, our findings provide new evidence that PB2 has protective potential against CS‐induced liver injury, which might be closely linked to the inhibition of Shh signalling pathway.

Bioactive phenolic components and potential health effects of chestnut shell: A review

Chestnut kernels are often used for direct consumption; or processed to produce marron glacé, chestnut purée, and gluten-free products, while chestnut by-products (inner shell and outer shell) are treated as waste residues. Many in vivo and in vitro studies have proved how chestnut shell extract functions as an antioxidant and exhibits anticancer, anti-inflammatory, antidiabetic, and anti-obesity activities. This review introduces the main components of phenolic compounds in chestnut shells, traditional and modern extraction methods, and reported potential health effects. The aim is to have a better understanding of the functional active ingredients in chestnut shells and their value-added uses, to increase understanding of future applications of this agricultural and sideline product in the food, pharmaceutical, and cosmetic industries. PRACTICAL APPLICATIONS: In recent years, chestnut shells have become a hot research topic because of their rich bioactive ingredients. Due to the large amount of phenolic compounds in chestnut shells and their potential health functions (antioxidant, anticancer, antibacterial, anti-inflammatory, hypoglycemic, and treatment of obesity), extracts of chestnut shells have high biological value in the treatment of diseases. Therefore, this review introduces the main components of phenolic compounds in chestnut shells, traditional and modern extraction methods, and the potential health effects of these compounds. The aim of this review is to better understand the functional, active ingredients in chestnut shells and their value-added uses, and to increase understanding of future applications of this agricultural and sideline product in the food, pharmaceutical, and cosmetic industries.

Procyanidin B2 induces apoptosis and autophagy in gastric cancer cells by inhibiting Akt/mTOR signaling pathway

Background

Procyanidin B2 (PB2), a unique component of the grape seed and other medicinal plants. PB2 has shown wide anticancer activity in various human cancer cells. However, it remains unclear about the biological effects and associated mechanisms of PB2 on gastric cancer cells.

Methods

Cell proliferation was measured by CCK8 assay, and cellular lactate dehydrogenase (LDH) release was measured in the culture medium. Cellular apoptosis was observed via TUNEL staining assay and measured by caspase-3 and -9 activities. Autophagy was observed by LC3 staining. Western blot analysis was performed to verify autophagy-associated proteins (Beclin1 and Atg5) and Akt-mTOR pathway.

Results

PB2 reduced the viability of BGC-823 and SGC-7901 cells in a concentration-dependent manner. Furthermore, PB2 induced increased apoptosis rate of gastric cancer cells and enhanced caspase-3 and -9 activities. Simultaneously, PB2 triggered autophagy in gastric cancer cells, with enhanced LC3 staining and increased expression of Beclin1 and Atg5, while the inhibition of autophagy by 3-MA reversed the PB2-induced suppression on cell viability. In addition, PB2 significantly decreased p-Akt and p-mTOR protein expression of gastric cancer cells.

Conclusion

PB2 exerts anti-proliferative and apoptotic effects and induces autophagy by modulating Akt/mTOR signaling pathway. PB2 may be developed as a potential therapeutic drug for gastric cancer.

Pharmacokinetic of gastrodigenin rhamnopyranoside from Moringa seeds in rodents

Gastrodigenin rhamnopyranoside (GR) is a hepatoprotective compound that exists in Moringa oleifera seeds. However, the UPLC-MS/MS method for the determination of GR (in-vitro/in-vivo) is lacking clarification. Herein, this study established the UPLC-MS/MS technique, which was effective and sensitive for the investigation of the pharmacokinetics and biodistribution of GR in rats and mice. The separation was achieved with a Shim-pack XR-ODS III C₁₈ column (2.0 × 75 mm, 1.6 μm) at 40 °C, while the mobile phase (Acetonitrile/0.1% Formic acid =12:82, v/v) was at an eluting rate of 0.2 mL/min. The Multiple Reaction Monitoring (MRM) was selected for quantification, i.e., m/z [M + HCOO]^- 314.9 → 269 for GR and m/z [M + HCOO] ^- 182.85 → 137 for Tyrosol as the internal standard. The calibration curves were linearly ranged from 10 to 2500 ng/mL (r ≥ 0.999) with a lower-limit-of-quantification (LLOQ) of 10 ng/mL in the various biological samples (plasma, liver, heart, lung, spleen, brain, kidney). The intra- and inter-day precision was within 5%, while accuracy ranged from -11.4% - 8.33%. Recovery and matrix effect were with 80.32 to 101.31% and 90.36 to 103.76%, respectively, in a reasonable range. After oral and intravenous administration, GR was detected within 3 h but decreased rapidly in plasma, indicating fast elimination. Also, GR was quickly distributed in the various tissues, particularly in the kidney and spleen. The results demonstrated that the established UPLC-MS/MS method was highly linear, precise and accurate with the potential to be used for the quantitative analysis of GR in-vivo.

In vitro/in vivo hepatoprotective properties of 1-O-(4-hydroxymethylphenyl)-α-L-rhamnopyranoside from Moringa oleifera seeds against carbon tetrachloride-induced hepatic injury

1-O-(4-hydroxymethylphenyl)-α-L-rhamnopyranoside (MPG) is a phenolic glycoside that exists in Moringa oleifera seeds with various health benefits, whereas its hepatoprotective effect is lacking clarification. Herein, MPG was isolated from Moringa oleifera seeds, and its hepatoprotection against CCl₄-induced hepatotoxicity in L02 cells and ICR mice was investigated. Toxicity studies showed that MPG did not induce significant changes in organ coefficients and histological analysis, as well as exhibited no cytotoxicity. In vitro studies indicated that MPG substantially increased cell viability and intracellular SOD activities, and significantly inhibited LDH leakage in CCl₄-treated cells. In vivo studies demonstrated that MPG significantly alleviated CCl₄-induced hepatotoxicity in mice, as indicated by diagnostic indicators of hepatic injury, as well as the histopathological analysis. Moreover, MPG reduced the lipid peroxidation levels and regulated the inflammatory cytokines. Notably, MPG substantially suppressed the significant elevation of ROS production in hepatocytes of mice intoxicated with CCl₄. Moreover, TUNEL assay demonstrated that MPG obviously inhibited hepatic apoptosis induced by CCl₄. Altogether, these results suggested that MPG has excellent liver-protecting effects against hepatocytotoxicity induced by CCl₄ in mice and L02 cells, which can be further developed as a valuable functional food additive or drug for the treatment of hepatic injury.

Castanea mollissima shell prevents an over expression of inflammatory response and accelerates the dermal wound healing

ETHNOPHARMACOLOGICAL RELEVANCE

Castanea mollissima shell (CMS) has been used for wound healing in China as traditional medicine. The shell is directly applied on the wounded skin as fine powder or as water maceration.

AIM OF THE STUDY

To investigate the wound healing activity of CMS and the potential mechanism of anti-inflammatory activity.

MATERIALS AND METHODS

The effects of ethanol extract of CMS (ECMS) on nitricoxide (NO), tumor necrosis factor (TNF)-α and interleukin (IL)- 6 productions in lipopolysaccharide (LPS)-treated RAW 264.7 cells were explored by enzyme linked immunosorbent assay (ELISA) in vitro. To study wound healing properties of ECMS in vivo, excision and incision wound models were performed on rats. Inflammatory cytokines from wound biopsies such as NO, TNF-α and IL-6 production were tested by ELISA. mRNA levels of iNOS, cyclooxygenase (COX) -2 and TNF-α were detected by real-time Polymerase Chain Reaction (PCR), and protein levels of IL-1β and Heme Oxygenase (HO) -1 were analyzed by Western blotting.

RESULTS

ECMS potently inhibited LPS-induced production of IL-6, NO and TNF-α in RAW 264.7 cells. The presence of quercetin, kaempferol, ursolic acid and gallic acid in ECMS might be responsible for its anti-inflammatory activity. 3% and 5% w/w ECMS significantly accelerated the wound healing process in both wound models, evidenced by the faster rate of wound contraction, epithelialization, increased hydroxyproline content, high tensile strength, decreased level of inflammatory markers compared to the control group. Histopathological studies also revealed the amelioration of wound healing by re-epithelialization, collagenation and vascularization of wounded skin sample in ECMS treated groups.

CONCLUSION

The experimental data revealed that CMS had ability to prevent exaggerated inflammation and accelerates wound epithelialization and might be beneficial for healing dermal wounds.

H2O2 treatment or serum deprivation induces autophagy and apoptosis in naked mole-rat skin fibroblasts by inhibiting the PI3K/Akt signaling pathway

Naked mole-rats (NMR; Heterocephalus glaber) display extreme longevity and resistance to cancer. Here, we examined whether autophagy contributes to the longevity of NMRs by assessing the effects of the PI3K/Akt pathway inhibitor LY294002 and the autophagy inhibitor chloroquine (CQ) on autophagy and apoptosis in NMR skin fibroblasts. Serum starvation, H2O2 treatment, and LY294002 treatment all increased the LC3-II/LC3-I ratio and numbers of double-membraned autophagosomes and autophagic vacuoles, and decreased levels of p70S6K, p-Akt^Ser473, and p-Akt^Thr308. By contrast, CQ treatment decreased p70S6K, Akt^Ser473, and Akt^Thr308 levels. The Bax/Bcl-2 ratio increased after 12 h of exposure to LY294002 or CQ. These data show that inhibiting the Akt pathway promotes autophagy and apoptosis in NMR skin fibroblasts. Furthermore, LY294002 or CQ treatment decreased caspase-3, p53, and HIF1-α levels, suggesting that serum starvation or H2O2 treatment increase autophagy and apoptosis in NMR skin fibroblasts by inhibiting the PI3K/Akt pathway. CQ-induced inhibition of late autophagy stages also prevented Akt activation and induced apoptosis. Finally, the HIF-1α and p53 pathways were involved in serum starvation- or H2O2-induced autophagy in NMR skin fibroblasts.

Afatinib Decreases P-Glycoprotein Expression to Promote Adriamycin Toxicity of A549T Cells

We investigated the reversal effect of afatinib (AFT) on activity of adriamycin (ADR) in A549T cells and clarified the related molecular mechanisms. A549T cells overexpressing P-glycoprotein (P-gp) were resistant to anticancer drug ADR. AFT significantly increased the antitumor activity of ADR in A549T cells. AFT increased the intracellular concentration of ADR by inhibiting the function and expression of P-gp at mRNA and protein levels in A549T cells. Additionally, the reversal effect of AFT on P-gp mediated multidrug resistance (MDR) might be related to the inhibition of PI3K/Akt pathway. Cotreatment with AFT and ADR could enhance ADR-induced apoptosis and autophagy in A549T cells. Meanwhile, the co-treatment significantly induced cell apoptosis and autophagy accompanied by increased expression of cleaved caspase-3, PARP, LC3B-II, and beclin 1. Apoptosis inhibitors had no significant effect on cell activity, while autophagy inhibitors decreased cell viability, suggesting that autophagy may be a self protective mechanism of cell survival in the absence of chemotherapy drugs. Interestingly, when combined with AFT and ADR, inhibition of apoptosis and/or autophagy could enhance cell viability. These results indicated that in addition to inhibit P-gp, ADR-induced apoptosis, and autophagy promoted by AFT contributed to the antiproliferation effect of combined AFT and ADR on A549T cells. These findings provide evidence that AFT combined ADR may achieve a better therapeutic effect to lung cancer in clinic. J. Cell. Biochem. 119: 414-423, 2018. © 2017 Wiley Periodicals, Inc.

Anticancer effect of Saussurea lappa extract via dual control of apoptosis and autophagy in prostate cancer cells

To demonstrate the mechanisms of the curative effect of Saussurea lappa ethanol extract (SLE) against prostate cancer, we evaluated the effect of SLE on the induction of apoptosis and autophagy and investigated whether SLE-induced autophagy exerts a pro-survival or pro-apoptotic effect in lymph node carcinoma of the prostate (LNCaP) prostate cancer cells. SLE was prepared using 100% ethanol and added to LNCaP cells for 24 hours. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and cell apoptosis was evaluated by Tali assay. The expression of apoptosis-related mRNA and proteins was analyzed by quantitative real-time RT-PCR and western blotting. SLE treatment decreased the viability of LNCaP cells and increased Bax expression while suppressing the expression of pro-caspases-8/9/3, PARP, Bid, and Bcl-2, thereby inducing apoptosis in LNCaP cells. Cell proliferation related proteins, including p-Akt, androgen receptor, and prostate-specific antigen, were suppressed by SLE treatment. SLE also induced autophagy in LNCaP cells, and inhibition of autophagy enhanced the apoptosis induced by SLE treatment. These results suggest that SLE exerts anticancer effects through the induction of both cellular apoptosis and autophagy, and apoptotic cell death can be facilitated by blocking autophagy in SLE-treated LNCaP cells. Therefore, SLE might be a potential anticancer agent for the treatment of prostate cancer.

Spinosad induces autophagy of Spodoptera frugiperda Sf9 cells and the activation of AMPK/mTOR signaling pathway

Spinosad, a high-selectivity neural toxin, has been widely used in agricultural production. However, the mode of action of spinosad on insect non-neural cells is not yet clear and hence requires further investigation. Therefore, to reveal the cytotoxic mechanisms of spinosad, we investigated whether and how it can induce autophagic cell death. After treating Sf9 cells with spinosad, the resulting autophagosome was observed by transmission electron microscopy and monodansylcadaverine staining. Interestingly, spinosad induced the accumulation of Beclin-1, degradation of p62, and intensification of LC3-B formation and translocation and thus autophagy, whereas, 3-MA treatment reverted the phenotype. Under ATP depletion conditions, spinosad induced autophagy of Sf9 cells and activation of the AMPK/mTOR signaling pathway.

Ginsenoside PPD's Antitumor Effect via Down-Regulation of mTOR Revealed by Super-Resolution Imaging

Derived from Panax ginseng, the natural product 20(S)-Protopanaxadiol (PPD) has been reported for its cytotoxicity against several cancer cell lines. The molecular mechanism is, however, not well understood. Here we show that PPD significantly inhibits proliferation, induces apoptosis and causes G2/M cell cycle arrest in human laryngeal carcinoma cells (Hep-2 cells). PPD also decreases the levels of proteins related to cell proliferation. Moreover, PPD-induced apoptosis is characterized by a dose-dependent down-regulation of Bcl-2 expression and up-regulation of Bax, and is accompanied by the activation of Caspase-3 as well. Further molecular mechanism is revealed by direct stochastic optical reconstruction microscopy (dSTORM)—a novel high-precision localization microscopy which enables effective resolution down to the order of 10 nm. It shows the expression and spatial arrangement of mTOR and its downstream effectors, demonstrating that this ginsenoside exerts its excellent anticancer effects via down-regulation of mTOR signaling pathway in Hep-2 cells. Taken together, our findings elucidate that the antitumor effect of PPD is associated with its regulation of mTOR expression and distribution, which encourages further studies of PPD as a promising therapeutic agent against laryngeal carcinoma.