Baicalein Triggers Autophagy and Inhibits the Protein Kinase B/Mammalian Target of Rapamycin Pathway in Hepatocellular Carcinoma HepG2 Cells

The most recent progress of baicalein in its anti-neoplastic effects and mechanisms

Problems, such as toxic side effects and drug resistance of chemoradiotherapy, target therapy and immunotherapy accompanying the current anti-cancer treatments, have become bottlenecks limiting the clinical benefit for patients. Therefore, it is urgent to find promising anti-cancer strategies with higher efficacy and lesser side effects. Baicalein, a flavonoid component derived from the Chinese medicine scutellaria baicalensis, has been widely studied for its remarkable anti-cancer activity in multiple types of malignancies both at the molecular and cellular levels. Baicalein exerts its anti-tumor effects by inhibiting angiogenesis, invasion and migration, inducing cell apoptosis and cell cycle arrest, as well as regulating cell autophagy, metabolism, the tumor microenvironment and cancer stem cells with no obvious toxic side effects. The role of classic signaling pathways, such as PI3K/AKT/mTOR, MAPK, AMPK, Wnt/β-catenin, JAK/STAT3, MMP-2/-9, have been highlighted as the major targets for baicalein exerting its anti-malignant potential. Besides, baicalein can regulate the relevant non-coding RNAs, such as lncRNAs, miRNAs and circ-RNAs, to inhibit tumorigenesis and progression. In addition to the mentioned commonalities, baicalein shows some specific anti-tumor characteristics in some specific cancer types. Moreover, the preclinical studies of the combination of baicalein and chemoradiotherapy pave the way ahead for developing baicalein as an adjunct treatment with chemoradiotherapy. Our aim is to summary the role of baicalein in different types of cancer with its mechanisms based on in vitro and in vivo experiments, hoping providing proof for baicalein serving as an effective and safe compound for cancer treatment in clinic in the future.

Evidence and possible mechanism of Scutellaria baicalensis and its bioactive compounds for hepatocellular carcinoma treatment

BACKGROUND

Traditional Chinese medicines have been reported to have outstanding effects in the treating of hepatocellular carcinoma. Scutellaria baicalensis (S. baicalensis) has demonstrated anti-tumor, anti-angiogenic, and anti-inflammatory properties. Baicalein, wogonin, and baicalin are the main pharmacologically bioactive compounds of S. baicalensis.

METHODS

Eight electronic databases were searched to select articles published from their inception to 30 May 2022. For selected articles, clinical and preclinical data was obtained on the use of S. baicalensis and its bioactive compounds in hepatocellular carcinoma therapy. Statistical analyses were performed using RevMan version 5.3 and Stata software. Quality assessment of the studies was performed using Cochrane and Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE)'s risk of bias tools.

RESULTS

Seven clinical and 17 preclinical in vivo studies along with 31 in vitro studies were included in this research. Meta-analysis showed that a Chinese herbal medicine preparation, with S. baicalensis as the sovereign herb, combined with Transcatheter arterial chemoembolization (TACE) or primary treatment, could lead to a significantly improved tumor objective response rate (Risk ratio (RR) = 1.57, 95% confidence interval (CI): [1.30, 1.90], p < 0.00001). Scutellaria baicalensis-based extracts (standard mean difference (SMD) = -0.86, 95%CI: [-1.20, -0.53], p < 0.00001), baicalein (SMD = -4.80, 95%CI: [-6.66, - 2.95], p < 0.00001), baicalin (SMD = -2.28, 95%CI [-3.26, -1.30], p < 0.00001) and wogonin (SMD = -1.41, 95%CI [-2.26, -0.57], p < 0.00001) slowed tumor growth in vivo. These outcomes might be linked to the mechanism by which S. baicalensis promotes apoptosis, induces autophagy, and blocks the expression of vascular endothelial growth factor (p < 0.05).

CONCLUSION

Based on experimental and clinical evidence, we believe that S. baicalensis and its bioactive compounds have therapeutic potential and plausible mechanisms of action against hepatocellular carcinoma, in terms of efficacy and safety.

Baicalein as Promising Anticancer Agent: A Comprehensive Analysis on Molecular Mechanisms and Therapeutic Perspectives

Despite significant therapeutic advancements for cancer, an atrocious global burden (for example, health and economic) and radio- and chemo-resistance limit their effectiveness and result in unfavorable health consequences. Natural compounds are generally considered safer than synthetic drugs, and their use in cancer treatment alone, or in combination with conventional therapies, is increasingly becoming accepted. Interesting outcomes from pre-clinical trials using Baicalein in combination with conventional medicines have been reported, and some of them have also undergone clinical trials in later stages. As a result, we investigated the prospects of Baicalein, a naturally occurring substance extracted from the stems of Scutellaria baicalensis Georgi and Oroxylum indicum Kurz, which targets a wide range of molecular changes that are involved in cancer development. In other words, this review is primarily driven by the findings from studies of Baicalein therapy in several cancer cell populations based on promising pre-clinical research. The modifications of numerous signal transduction mechanisms and transcriptional agents have been highlighted as the major players for Baicalein’s anti-malignant properties at the micro level. These include AKT serine/threonine protein kinase B (AKT) as well as PI3K/Akt/mTOR, matrix metalloproteinases-2 & 9 (MMP-2 & 9), Wnt/-catenin, Poly(ADP-ribose) polymerase (PARP), Mitogen-activated protein kinase (MAPK), NF-κB, Caspase-3/8/9, Smad4, Notch 1/Hes, Signal transducer and activator of transcription 3 (STAT3), Nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein-1 (Keap 1), Adenosine monophosphate-activated protein kinase (AMPK), Src/Id1, ROS signaling, miR 183/ezrin, and Sonic hedgehog (Shh) signaling cascades. The promise of Baicalein as an anti-inflammatory to anti-apoptotic/anti-angiogenic/anti-metastatic medicinal element for treating various malignancies and its capability to inhibit malignant stem cells, evidence of synergistic effects, and design of nanomedicine-based drugs are altogether well supported by the data presented in this review study.

Autophagy and beyond: Unraveling the complexity of UNC-51-like kinase 1 (ULK1) from biological functions to therapeutic implications

UNC-51-like kinase 1 (ULK1), as a serine/threonine kinase, is an autophagic initiator in mammals and a homologous protein of autophagy related protein (Atg) 1 in yeast and of UNC-51 in Caenorhabditis elegans. ULK1 is well-known for autophagy activation, which is evolutionarily conserved in protein transport and indispensable to maintain cell homeostasis. As the direct target of energy and nutrition-sensing kinase, ULK1 may contribute to the distribution and utilization of cellular resources in response to metabolism and is closely associated with multiple pathophysiological processes. Moreover, ULK1 has been widely reported to play a crucial role in human diseases, including cancer, neurodegenerative diseases, cardiovascular disease, and infections, and subsequently targeted small-molecule inhibitors or activators are also demonstrated. Interestingly, the non-autophagy function of ULK1 has been emerging, indicating that non-autophagy-relevant ULK1 signaling network is also linked with diseases under some specific contexts. Therefore, in this review, we summarized the structure and functions of ULK1 as an autophagic initiator, with a focus on some new approaches, and further elucidated the key roles of ULK1 in autophagy and non-autophagy. Additionally, we also discussed the relationships between ULK1 and human diseases, as well as illustrated a rapid progress for better understanding of the discovery of more candidate small-molecule drugs targeting ULK1, which will provide a clue on novel ULK1-targeted therapeutics in the future.

Baicalein Inhibits the SMYD2/RPS7 Signaling Pathway to Inhibit the Occurrence and Metastasis of Lung Cancer

Objective

This study investigated the potential effects of Baicalein on proliferation, migration, and invasion of human lung cancer A549 and NCI-H1299 cells and its possible mechanisms.

Methods

The effects of Baicalein on proliferation and invasion of A549 and NCI-H1299 cells were detected by MTT assay, clonogenesis assay, and Transwell assay. A subcutaneous transplanted tumor model was used to evaluate the effects of SMYD2 and Baicalein on the proliferation of lung cancer. Baicalein inhibited in SMYD2/RPS7 signaling pathway in tumor cells was also detected by qRT-PCR.

Results

Baicalein significantly inhibited the growth of lung cancer cells. In addition, Baicalein significantly reduced the rate of A549 and NCI-H1299 cell invasion and clone formation in a dose-dependent manner. Animal experiments showed that both SMYD2 and Baicalein treatments could inhibit lung cancer tumor proliferation. Mechanism studies suggest that Baicalein inhibits the SMYD2/RPS7 signaling pathway.

Conclusion

These results indicated that Baicalein could inhibit the proliferation, migration, and invasion of LUNG cancer A549 and NCI-H1299 cells. Baicalein inhibits cell proliferation by downregulating the SMYD2/RPS7 signaling pathway.

Baicalein Activates Parkin-Dependent Mitophagy through NDP52 and OPTN

The elimination of intracellular components by autophagy maintains metabolic homeostasis and is a quality-control pathway that enables organelle regeneration. Mitophagy is a type of selective autophagy that regulates mitochondrial turnover, and the dysregulation of mitophagy has been implicated in the pathogenesis of liver diseases. However, the detailed molecular mechanism underlying mitophagy regulation in liver cells remains unclear, and the small molecules that may potentially modulate hepatic mitophagy are still unavailable. Here, we report that baicalein, a flavonoid extracted from Scutellaria baicalensis, induces the entire autophagy that proceeds through the autolysosome maturation stage in human hepatoma cells. In addition, baicalein-induced autophagy is demonstrated to target mitochondria for degradation. Further studies show that baicalein triggers the translocation of Parkin and TBK1 to mitochondria to induce mitophagy. Moreover, the phosphorylation of TBK1 at Ser172 and ubiquitin at Ser65 is shown to trigger mitophagy in baicalein-treated cells. Furthermore, two specific autophagy cargo receptors, NDP52 and OPTN, that function in baicalein-activated mitophagy are identified. Taken together, these findings not only delineate the molecular process of Parkin-dependent mitophagy in liver cells, but also reveal baicalein as a novel inducer of hepatic mitophagy.

The Role of Endoplasmic Reticulum Stress and NLRP3 Inflammasome in Liver Disorders

The endoplasmic reticulum (ER) is a key organelle responsible for the synthesis, modification, folding and assembly of proteins; calcium storage; and lipid synthesis. When ER homeostatic balance is disrupted by a variety of physiological and pathological factors—such as glucose deficiency, environmental toxins, Ca²⁺ level changes, etc.—ER stress can be induced. Abnormal ER stress can be involved in many diseases. NOD-like receptor family pyrin domain-containing 3 (NLRP3), an intracellular receptor, can perceive internal and external stimuli. It binds to apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1 to assemble into a protein complex called the NLRP3 inflammasome. Evidence indicates that ER stress and the NLRP3 inflammasome participate in many pathological processes; however, the exact mechanism remains to be understood. In this review, we summarized the role of ER stress and the NLRP3 inflammasome in liver disorders and analyzed the mechanisms, to provide references for future related research.

An overview of pharmacological activities of baicalin and its aglycone baicalein: New insights into molecular mechanisms and signaling pathways

The flavonoids, baicalin, and its aglycone baicalein possess multi-fold therapeutic properties and are mainly found in the roots of Oroxylum indicum (L.) Kurz and Scutellaria baicalensis Georgi. These flavonoids have been reported to possess various pharmacological properties, including antibacterial, antiviral, anticancer, anticonvulsant, anti-oxidant, hepatoprotective, and neuroprotective effects. The pharmacological properties of baicalin and baicalein are due to their abilities to scavenge reactive oxygen species (ROS) and interaction with various signaling molecules associated with apoptosis, inflammation, autophagy, cell cycle, mitochondrial dynamics, and cytoprotection. In this review, we summarized the molecular mechanisms underlying the chemopreventive and chemotherapeutic applications of baicalin and baicalein in the treatment of cancer and inflammatory diseases. In addition, the preventive effects of baicalin and baicalein on mitochondrial dynamics and functions were highlighted with a particular emphasis on their anti-oxidative and cytoprotective properties. The current review highlights could be useful for future prospective studies to further improve the pharmacological applications of baicalein and baicalin. These studies should define the threshold for optimal drug exposure, dose optimization and focus on therapeutic drug monitoring, objective disease markers, and baicalin/baicalein drug levels.

Anti-Hepatocellular Carcinoma Biomolecules: Molecular Targets Insights

This report explores the available curative molecules directed against hepatocellular carcinoma (HCC). Limited efficiency as well as other drawbacks of existing molecules led to the search for promising potential alternatives. Understanding of the cell signaling mechanisms propelling carcinogenesis and driven by cell proliferation, invasion, and angiogenesis can offer valuable information for the investigation of efficient treatment strategies. The complexity of the mechanisms behind carcinogenesis inspires researchers to explore the ability of various biomolecules to target specific pathways. Natural components occurring mainly in food and medicinal plants, are considered an essential resource for discovering new and promising therapeutic molecules. Novel biomolecules normally have an advantage in terms of biosafety. They are also widely diverse and often possess potent antioxidant, anti-inflammatory, and anti-cancer properties. Based on quantitative structure-activity relationship studies, biomolecules can be used as templates for chemical modifications that improve efficiency, safety, and bioavailability. In this review, we focus on anti-HCC biomolecules that have their molecular targets partially or completely characterized as well as having anti-cancer molecular mechanisms that are fairly described.

Autophagy Modulators From Chinese Herbal Medicines: Mechanisms and Therapeutic Potentials for Asthma

Asthma has become a global health issue, suffering more than 300 million people in the world, which is a heterogeneous disease, usually characterized by chronic airway inflammation and airway hyperreactivity. Combination of inhaled corticosteroids (ICS) and long acting β-agonists (LABA) can relieve asthma symptoms and reduce the frequency of exacerbations, especially for patients with refractory asthma, but there are limited treatment options for people who do not gain control on combination ICS/LABA. The increase in ICS dose generally provides little additional benefit, and there is an increased risk of side effects. Therefore, therapeutic interventions integrating the use of different agents that focus on different targets are needed to overcome this set of diseases. Some findings suggest autophagy is closely correlated with the severity of asthma through eosinophilic inflammation, and its modulation may provide novel therapeutic approaches for severe allergic asthma. The chinese herbal medicine (CHM) have been demonstrated clinically as potent therapeutic interventions for asthma. Moreover some reports have found that the bioactive components isolated from CHM could modulate autophagy, and exhibit potent Anti-inflammatory activity. These findings have implied the potential for CHMs in asthma or allergic inflammation therapy via the modulation of autophagy. In this review, we discuss the basic pathomechanisms underpinning asthma, and the potential role of CHMs in treating asthma with modulating autophagy.

Pseudo-ginsenoside Rh2 Induces Protective Autophagy in Hepatocellular Carcinoma HepG2 Cells

BACKGROUND

Pseudo-ginsenoside-Rh2 (pseudo-G-Rh2), a novel derivative of ginsenoside Rh2, is reported to exert a pro-apoptotic effect on various malignancies. However, whether this anti-cancer action of pseudo-G-Rh2 involves autophagy remains to be determined and explored.

OBJECTIVES

Investigation of pseudo-G-Rh2-induced apoptosis and autophagy and the underlying mechanism.

METHODS

In the present study, the MTT assay was used for evaluating cell viability and the lactate dehydrogenase (LDH) assay was performed to assess cell toxicity. Autophagy evaluation was performed using monodansylcadaverine (MDC) staining and transmission electron microscopy (TEM). The levels of autophagy-associated and apoptosis-associated proteins were determined using Western blotting. The Annexin V FITC/propidium iodide (PI) assay was used to assess apoptosis.

RESULTS

The Annexin V FITC/PI assay revealed that the percentage of apoptotic cells in HepG2 cells at concentrations 0, 20, 40, and 60 μM was 3.75%±1.37%, 5.70%±1.04%, 12.30%±2.10%, and 34.26%±4.73%, respectively. Pseudo-G-Rh2 was observed to significantly increase the expressions of BAX, cleaved-caspase-3, and cleaved-caspase-9, while it decreased the Bcl-2 expression. MDC and TEM analyses revealed that pseudo-G-Rh2 at concentrations 20, 40, and 60 μM significantly facilitated the accumulation of autophagosomes and autolysosomes within the HepG2 cells. Moreover, pseudo-G-Rh2 significantly increased the expressions of LC3 Ⅱ/LC3 Ⅰ, and Beclin-1 and decreased the expression of p62. The Annexin V FITC/PI assay also revealed that in comparison to the pseudo-G-Rh2 group, the concurrent treatment with pseudo-G-Rh2 and an autophagy inhibitor (CQ or 3-MA) significantly induced distinct apoptosis. In addition, pseudo-G-Rh2 activated AMPK and inhibited the PI3K/Akt/mTOR pathway in a concentration-dependent manner. Pseudo-G-Rh2 is similar to the current patents, which enhanced its anti-cancer activity by combining with autophagy inhibitors.

CONCLUSION

Pseudo-G-Rh2 could induce protective autophagy in HepG2 cells, at least in part, via AMPK and the PI3K/Akt/mTOR pathway.

Autophagy: Mechanisms and Therapeutic Potential of Flavonoids in Cancer

Autophagy, which is a conserved biological process and essential mechanism in maintaining homeostasis and metabolic balance, enables cells to degrade cytoplasmic constituents through lysosomes, recycle nutrients, and survive during starvation. Autophagy exerts an anticarcinogenic role in normal cells and inhibits the malignant transformation of cells. On the other hand, aberrations in autophagy are involved in gene derangements, cell metabolism, the process of tumor immune surveillance, invasion and metastasis, and tumor drug-resistance. Therefore, autophagy-targeted drugs may function as anti-tumor agents. Accumulating evidence suggests that flavonoids have anticarcinogenic properties, including those relating to cellular proliferation inhibition, the induction of apoptosis, autophagy, necrosis, cell cycle arrest, senescence, the impairment of cell migration, invasion, tumor angiogenesis, and the reduction of multidrug resistance in tumor cells. Flavonoids, which are a group of natural polyphenolic compounds characterized by multiple targets that participate in multiple pathways, have been widely studied in different models for autophagy modulation. However, flavonoid-induced autophagy commonly interacts with other mechanisms, comprehensively influencing the anticancer effect. Accordingly, targeted autophagy may become the core mechanism of flavonoids in the treatment of tumors. This paper reviews the flavonoid-induced autophagy of tumor cells and their interaction with other mechanisms, so as to provide a comprehensive and in-depth account on how flavonoids exert tumor-suppressive effects through autophagy.

Autophagy in white matter disorders of the CNS: mechanisms and therapeutic opportunities

Autophagy is a constitutive process that degrades, recycles and clears damaged proteins or organelles, yet, despite activation of this pathway, abnormal proteins accumulate in neurons in neurodegenerative diseases and in oligodendrocytes in white matter disorders. Here, we discuss the role of autophagy in white matter disorders, including neurotropic infections, inflammatory diseases such as multiple sclerosis, and in hereditary metabolic disorders and acquired toxic‐metabolic disorders. Once triggered due to cell stress, autophagy can enhance cell survival or cell death that may contribute to oligodendrocyte damage and myelin loss in white matter diseases. For some disorders, the mechanisms leading to myelin loss are clear, whereas the aetiological agent and pathological mechanisms are unknown for other myelin disorders, although emerging studies indicate that a common mechanism underlying these disorders is dysregulation of autophagic pathways. In this review we discuss the alterations in the autophagic process in white matter disorders and the potential use of autophagy‐modulating agents as therapeutic approaches in these pathological conditions. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Coptisine induces autophagic cell death through down-regulation of PI3K/Akt/mTOR signaling pathway and up-regulation of ROS-mediated mitochondrial dysfunction in hepatocellular carcinoma Hep3B cells

Coptisine is isoquinoline alkaloid derived from Coptidis Rhizoma and is known to have potential anti-cancer activity toward various carcinomas. Targeting autophagy is one of the main approaches for cancer therapy, but whether the anti-cancer efficacy of coptisine involves autophagy is still unclear. Therefore, this study investigated the effect of coptisine on autophagy in hepatocellular carcinoma (HCC) Hep3B cells, and identified the underlying mechanism. Our results showed that coptisine increased cytotoxicity and autophagic vacuoles in a concentration-dependent manner. Furthermore, the expressions of light chain 3 (LC3)-I/II, Beclin-1 and autophagy genes were markedly increased by coptisine, while the expression of p62 decreased. In addition, we found that pretreatment with bafilomycin A1, an inhibitor of autophagosome-lysosome fusion, markedly reduced coptisine-mediated autophagic cell death, but 3-methyladenine, an inhibitor for autophagosome formation did not. Moreover, our results showed that although coptisine up-regulated AMP-activated protein kinase (AMPK) that partially induced LC3-I/II, coptisine-mediated AMPK signaling did not directly regulate autophagic cell death. Additionally, we found that coptisine suppressed the phosphorylation of phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR), and this effect was notably enhanced by PI3K inhibitor LY294002. Meanwhile, coptisine significantly increased both the production of mitochondrial reactive oxygen species (ROS) and the recruitment of mitophagy-regulated proteins to mitochondria. Furthermore, N-acetylcysteine, a potential ROS scavenger, substantially suppressed the expression of mitophagy-regulated proteins and LC3 puncta by coptisine. Overall, our results demonstrate that coptisine-mediated autophagic cell death was regulated by PI3K/Akt/mTOR signaling and mitochondrial ROS production associated with mitochondrial dysfunction. Taken together, these findings suggest that coptisine exerts its anti-cancer effects through induction of autophagy in HCC Hep3B cells.

Recent Advances in Characterizing Natural Products that Regulate Autophagy

Autophagy, an intricate response to nutrient deprivation, pathogen infection, Endoplasmic Reticulum (ER)-stress and drugs, is crucial for the homeostatic maintenance in living cells. This highly regulated, multistep process has been involved in several diseases including cardiovascular and neurodegenerative diseases, especially in cancer. It can function as either a promoter or a suppressor in cancer, which underlines the potential utility as a therapeutic target. In recent years, increasing evidence has suggested that many natural products could modulate autophagy through diverse signaling pathways, either inducing or inhibiting. In this review, we briefly introduce autophagy and systematically describe several classes of natural products that implicated autophagy modulation. These compounds are of great interest for their potential activity against many types of cancer, such as ovarian, breast, cervical, pancreatic, and so on, hoping to provide valuable information for the development of cancer treatments based on autophagy.

Polyphenol-Mediated Autophagy in Cancer: Evidence of In Vitro and In Vivo Studies

One of the hallmarks of cellular transformation is the altered mechanism of cell death. There are three main types of cell death, characterized by different morphological and biochemical features, namely apoptosis (type I), autophagic cell death (type II) and necrosis (type III). Autophagy, or self-eating, is a tightly regulated process involved in stress responses, and it is a lysosomal degradation process. The role of autophagy in cancer is controversial and has been associated with both the induction and the inhibition of tumor growth. Autophagy can exert tumor suppression through the degradation of oncogenic proteins, suppression of inflammation, chronic tissue damage and ultimately by preventing mutations and genetic instability. On the other hand, tumor cells activate autophagy for survival in cellular stress conditions. Thus, autophagy modulation could represent a promising therapeutic strategy for cancer. Several studies have shown that polyphenols, natural compounds found in foods and beverages of plant origin, can efficiently modulate autophagy in several types of cancer. In this review, we summarize the current knowledge on the effects of polyphenols on autophagy, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of polyphenols for envisioning future therapies employing polyphenols as chemoadjuvants.

Inhibition of Autophagy Amplifies Baicalein-Induced Apoptosis in Human Colorectal Cancer

Baicalein is a Chinese herbal compound extracted from Scutellaria baicalensis that has anti-tumor properties. The aim of this study was to elucidate the mechanisms of action of baicalein against human colorectal cancer cell lines and to assess whether the anti-proliferative effects of baicalein may be amplified with autophagy inhibition. Human colon cancer cell lines (HT-29, HCT-116, SW480, and SW620) were treated with baicalein alone and in combination with the autophagy inhibitor chloroquine (CQ). Baicalein reduced cell viability in all four colon cancer lines in a dose-dependent fashion. Combination treatment of baicalein and the autophagy inhibitor CQ significantly decreased cell viability compared with baicalein alone in HT-29 and HCT-116 cell lines. Western blot analysis of the HCT-116 cell line treated with both baicalein and CQ demonstrated increased expression of LC3-II, a component of autophagy. The combination of baicalein with CQ culminated in activation of caspase-3-mediated apoptosis. These findings demonstrate that inhibition of autophagy enhanced apoptotic cell death induced by baicalein treatment in colon cancer cell lines. Future work will assess other targetable apoptotic pathways activated by baicalein and autophagy inhibition.

Targeting Autophagic Pathways by Plant Natural Compounds in Cancer Treatment

Nowadays, natural compounds of plant origin with anticancer effects have gained more attention because of their clinical safety and broad efficacy profiles. Autophagy is a multistep lysosomal degradation pathway that may have a unique potential for clinical benefit in the setting of cancer treatment. To retrieve articles related to the study, the databases of Google Scholar, Web of sciences, Medline and Scopus, using the following keywords: Autophagic pathways; herbal medicine, oncogenic autophagic pathways, tumor-suppressive autophagic pathways, and cancer were searched. Although natural plant compounds such as resveratrol, curcumin, oridonin, gossypol, and paclitaxel have proven anticancer potential via autophagic signaling pathways, there is still a great need to find new natural compounds and investigate the underlying mechanisms, to facilitate their clinical use as potential anticancer agents through autophagic induction.

Autophagy: A Potential Therapeutic Target of Polyphenols in Hepatocellular Carcinoma

Autophagy is a conserved biological phenomenon that maintains cellular homeostasis through the clearing of damaged cellular components under cellular stress and offers the cell building blocks for cellular survival. Aberrations in autophagy subsidize to various human pathologies, such as dementia, cardiovascular diseases, leishmaniosis, influenza, hepatic diseases, and cancer, including hepatocellular carcinoma (HCC). HCC is the fifth common mortal type of liver cancer globally, with an inhomogeneous topographical distribution and highest incidence tripled in men than women. Existing treatment procedures with liver cancer patients result in variable success rates and poor prognosis due to their drug resistance and toxicity. One of the pathophysiological mechanisms that are targeted during the development of anti-liver cancer drugs is autophagy. Generally, overactivated autophagy may lead to a non-apoptotic form of programmed cell death (PCD) or autophagic cell death or type II PCD. Emerging evidence suggests that manipulation of autophagy could induce type II PCD in cancer cells, acting as a potential tumor suppressor. Hence, altering autophagic signaling offers new hope for the development of novel drugs for the therapy of resistant cancer cells. Natural polyphenolic compounds, including flavonoids and non-flavonoids, execute their anticarcinogenic mechanism through upregulating tumor suppressors and autophagy by modulating canonical (Beclin-1-dependent) and non-canonical (Beclin-1-independent) signaling pathways. Additionally, there is evidence signifying that plant polyphenols target angiogenesis and metastasis in HCC via interference with multiple intracellular signals and decrease the risk against HCC. The current review offers a comprehensive understanding of how natural polyphenolic compounds exhibit their anti-HCC effects through regulation of autophagy, the non-apoptotic mode of cell death.

Induction of Autophagy by Baicalin Through the AMPK-mTOR Pathway Protects Human Skin Fibroblasts from Ultraviolet B Radiation-Induced Apoptosis

Background

Baicalin, a natural product isolated from Scutellaria radix, has been reported to exert anti-oxidant and anti-apoptotic effects on skin, but the underlying mechanism remains poorly understood. This study aimed to investigate the possible mechanism of anti-UVB effect of baicalin in human skin fibroblasts.

Methods

Cell proliferation was estimated by CCK-8 Kit. Apoptotic incidence was detected by flow cytometry with Annexin V-PE/PI apoptosis detection kit. Autophagy was determined by the evaluation of fluorescent LC3 puncta and Western blotting. Cell signalling was analysed by Western blotting.

Results

Baicalin exerted cytoprotective effects in UVB-induced HSFs. Moreover, baicalin increased autophagy and suppressed UVB-induced apoptosis of HSFs. Pretreatment with 3-MA, an autophagy inhibitor, attenuated baicalin-induced HSFs autophagy and promoted apoptosis. Baicalin activated AMPK, which leads to suppression of basal mTOR activity in cultured HSFs. Administration of compound C, an AMPK inhibitor, abrogated AMPK phosphorylation and increased mTOR phosphorylation and apoptosis compared with baicalin alone.

Conclusion

Taken together, these results indicate the important role of mTOR inhibition in UVB protection by baicalin and provide a new target and strategy for better prevention of UV-induced skin disorders.

Baicalein Induces Autophagy and Apoptosis through AMPK Pathway in Human Glioma Cells

Baicalein (BAI) is a natural flavonoid. It has been shown that BAI has anticancer effects, but the molecular mechanism is still unclear. The aim of the current study was to confirm whether or not BAI triggers autophagy and induces AMPK activation in glioma U251 cells. The Ad-mcherry-GFP-LC3B adenovirus experiments indicated that BAI induces glioma cell autophagy. Western blotting showed that the level of LC3II expression increased with the time and concentration of BAI. Following treatment with chloroquine, the expression of LC3 was enhanced Immunofluorescence also confirmed this result. At the same time, cleaved caspase-3, DAPI staining, and JC-1 staining revealed that apoptosis was also induced in the induction of autophagy. In addition, we found that BAI activates phosphorylation of AMPK, which is further confirmed using compound C in this process. When the phosphorylation of AMPK was inhibited, autophagy, and apoptosis were also inhibited. In conclusion, BAI induces autophagy and apoptosis through AMPK pathway. Surprisingly, our research provides new insight with the function of anticancer of BAI, and the potential of the promotion in glioma cell apoptosis might be related to autophagy activation. These results demonstrate the anticancer activity of BAI, which can be used as potential therapeutic agents for cancer therapy.

Traditional Chinese medicine combined with hepatic targeted drug delivery systems: A new strategy for the treatment of liver diseases

Liver diseases are clinically common and present a substantial public health issue. Many of the currently available drugs for the treatment of liver diseases suffer from limitations that include low hepatic distribution, lack of target effects, poor in vivo stability and adverse effects on other organs. Consequently, conventional treatment of hepatic diseases is ineffective. TCM is commonly used in the treatment of liver diseases worldwide, particularly in China, and has advantages over conventional therapy. HTDDS can be designed to enhance clinical efficacy in the treatment of liver diseases. We have conducted an extensive review of 335 studies reported since 1964. These included about 166 references involving the treatment of liver diseases with TCM (covering active components of TCM, single TCM and Chinese medicine formulas), 169 reports on HTDDS and background studies on liver-related diseases. Here we review the long history of TCM in the treatment of liver diseases.We have also reviewed the status of studies on active components of TCM using nanotechnology-based targeted delivery systems to provide support for further research and development of TCM-based targeted preparations for the treatment of liver disease.

Traditional Chinese medicine-combination therapies utilizing nanotechnology-based targeted delivery systems: a new strategy for antitumor treatment

Cancer is a major public health problem, and is now the world’s leading cause of death. Traditional Chinese medicine (TCM)-combination therapy is a new treatment approach and a vital therapeutic strategy for cancer, as it exhibits promising antitumor potential. Nano-targeted drug-delivery systems have remarkable advantages and allow the development of TCM-combination therapies by systematically controlling drug release and delivering drugs to solid tumors. In this review, the anticancer activity of TCM compounds is introduced. The combined use of TCM for antitumor treatment is analyzed and summarized. These combination therapies, using a single nanocarrier system, namely codelivery, are analyzed, issues that require attention are determined, and future perspectives are identified. We carried out a systematic review of >280 studies published in PubMed since 1985 (no patents involved), in order to provide a few basic considerations in terms of the design principles and management of targeted nanotechnology-based TCM-combination therapies.

Network Pharmacology and Bioinformatics Approach Reveals the Therapeutic Mechanism of Action of Baicalein in Hepatocellular Carcinoma

Liver cancer is the fourth leading cause of cancer death worldwide, and hepatocellular carcinoma (HCC) accounts for the greatest proportion of these deaths. Baicalein, a flavonoid isolated from the root of Scutellariae radix, is considered a potential candidate to treat HCC. However, the underlying molecular mechanisms remain poorly understood. In the present study, a network pharmacological approach was combined with microarray data (GSE95504) acquired from the Gene Expression Omnibus database to reveal the therapeutic mechanisms of action of baicalein at a systemic level. We identified 38 baicalein targets and 76 differently expressed genes (DEGs) following treatment with baicalein, including 55 upregulated and 21 downregulated genes. The DEGs were significantly enriched in the biological functions of apoptosis, endoplasmic reticulum stress, and PERK-mediated unfolded protein response. Protein-protein interaction (PPI) network construction and topological screening revealed a core module of PPIs including two baicalein targets, TP53 and CDK1, and two downregulated DEGs, HSPA1A and HSPA1B. Expression and survival data for these genes in the module derived from Gene Expression Profiling Interactive Analysis (GEPIA) were subjected to Kaplan–Meier analysis of overall survival and disease-free survival. Overexpression of CDK1, BRCA1, TUBB, HSPA1A, HSPA1B, and HSPA4 was associated with significantly worse overall survival, while overexpression of CDK1, CLU7, BRCA1, and TUBB was associated with significantly worse disease-free survival. These data suggest that baicalein exerts therapeutic effects against HCC via a PPI network involving TP53, CDK1, HSPA1A, and HSPA1B.

Glycolysis inhibition via mTOR suppression is a key step in cardamonin-induced autophagy in SKOV3 cells

Background

Autophagy occurs in cells that undergoing nutrient deprivation. Glycolysis rapidly supplies energy for the proliferation of cancer cells. Cardamonin inhibits proliferation and enhances autophagy by mTORC1 suppression in ovarian cancer cells. Here, we investigate the relationship between cardamonin-triggered autophagy and glycolysis inhibition via mTORC1 suppression.

Methods

Treated with indicated compounds, ATP content and the activity of hexokinase (HK) and lactate dehydrogenase (LDH) were analyzed by the assay kits. Autophagy was detected by monodansylcadaverin (MDC) staining. The relationship between cardamonin-triggered autophagy and glycolysis inhibition via mTORC1 suppression was analyzed by Western blot.

Results

We found that cardamonin inhibited the lactate secretion, ATP production, and the activity of HK and LDH. The results demonstrated that cardamonin enhanced autophagy in SKOV3 cells, as indicated by acidic compartments accumulation, microtubule-associated protein 1 Light Chain 3-II (LC3-II) and lysosome associated membrane protein 1 up-regulation. Our results showed that the activation of mTORC1 signaling and the expression HK2 were reduced by cardamonin; whereas the phosphorylation of AMPK (AMP-activated protein kinase) was increased. We also confirmed that the AMPK inhibitor, Compound C, reversed cardamonin-induced upregulation of LC3-II.

Conclusion

These results suggest that cardamonin-induced autophagy is associated with inhibition on glycolysis by down-regulating the activity of mTORC1 in ovarian cancer cells.

Arterial Infusion of Rapamycin in the Treatment of Rabbit Hepatocellular Carcinoma to Improve the Effect of TACE

Background

Hepatocellular carcinoma is one of the leading causes of cancer-related death. Hepatic transcatheter arterial chemo-embolization (TACE) is commonly used clinically for advanced hepatocellular carcinoma treatment.

AIM

The aim of this study was to evaluate whether arterial infusion of rapamycin can improve the effect of TACE in treatment of rabbit hepatocellular carcinoma.

Material and Methods

Eighteen healthy New Zealand white rabbits weighing 2.6 ± 0.3 kg were used in a standardised hepatocellular carcinoma model and randomly divided into three groups of 6 rabbits. Group A: the rabbits were treated with rapamycin and TACE by administering arterial perfusion of 2 mg/kg rapamycin + 1 mg/kg epirubicin, 0.2 mg/kg mitomycin, and lipiodol emulsion embolization. Group B: rapamycin was reduced to 1 mg/kg. And for Group C, the rabbits received only TACE treatment. 14 days post operation, CT scan and digital subtraction angiography (DSA) was performed to examine TACE efficacy. The rabbits were killed by air embolism and the expression of HIF-1a, VEGF, iNOS, and CD34 were measured in an immunohistochemical assay of thetumor tissue.

Results

HIF-1a, VEGF and iNOS protein expression in Group A was significantly lower than that of Group B and Group C (P<0.05). The tumor MVD in group C was significantly higher than that of group A and group B (P<0.05); and the tumor MVD of group B was significantly higher than group A (P<0.05).

Conclusion

Arterial infusion of rapamycin combined with TACE can improve treatment efficacy by decreasing HIF-1a, VEGF, iNOS and CD34 expression.

Delphinidin induced protective autophagy via mTOR pathway suppression and AMPK pathway activation in HER-2 positive breast cancer cells

Background

We have previously demonstrated the anticancer effect of anthocyanins. In this study, we explored the biological activities of delphinidin, the most common of the anthocyanidin monomers, that were related to autophagy in HER-2 positive breast cancer MDA-MB-453 and BT474 cells.

Methods

The effects of various doses of delphinidin on the proliferation and apoptosis of MDA-MB-453 and BT474 cells were analysed. Autophagy was identified as a critical factor that influenced chemotherapy, and the autophagic mechanism in delphinidin-treated cells was investigated. The autophagy inhibitors, 3-MA and BA1, were used to analyse the effects of autophagy inhibition.

Results

Delphinidin inhibited proliferation, promoted apoptosis, and induced autophagy in MDA-MB-453 and BT474 cells in a dose-dependent manner. The inhibition of autophagy enhanced the delphinidin-induced apoptosis and antiproliferative effect in both HER-2 positive breast cancer cells. In addition, delphinidin induced autophagy via suppression of the mTOR signalling pathway and activation of the AMPK signalling pathway in HER-2 positive breast cancer cells.

Conclusions

Collectively, the results showed that delphinidin induced apoptosis and autophagy in HER-2 positive breast cancer cells and that autophagy was induced via the mTOR and AMPK signalling pathways. The suppression of autophagy promoted the anticancer effects of delphinidin.

The Potential and Action Mechanism of Polyphenols in the Treatment of Liver Diseases

Liver disease, involving a wide range of liver pathologies from fatty liver, hepatitis, and fibrosis to cirrhosis and hepatocellular carcinoma, is a serious health problem worldwide. In recent years, many natural foods and herbs with abundant phytochemicals have been proposed as health supplementation for patients with hepatic disorders. As an important category of phytochemicals, natural polyphenols have attracted increasing attention as potential agents for the prevention and treatment of liver diseases. The striking capacities in remitting oxidative stress, lipid metabolism, insulin resistance, and inflammation put polyphenols in the spotlight for the therapies of liver diseases. It has been reported that many polyphenols from a wide range of foods and herbs exert therapeutic effects on liver injuries via complicated mechanisms. Therefore, it is necessary to have a systematical review to sort out current researches to help better understand the potentials of polyphenols in liver diseases. In this review, we aim to summarize and update the existing evidence of natural polyphenols in the treatment of various liver diseases by in vitro, in vivo, and clinical studies, while special attention is paid to the action mechanisms.

Baicalein protects tert‑butyl hydroperoxide‑induced hepatotoxicity dependent of reactive oxygen species removal

Baicalein (BA), one of the major bioactive flavonoids isolated from Scutellariae Radix, possesses various pharmacological activities. The present study aimed to investigate the protective effects of BA on tert‑butyl hydroperoxide (t‑BHP)‑induced hepatotoxicity, and to investigate the potential mechanisms in LO2 cells. BA was demonstrated to possess protective properties against t‑BHP injury in LO2 cells, as evidenced by MTT and lactate dehydrogenase assays. BA significantly prevented t‑BHP‑induced depolarization of mitochondrial membrane potential (MMP), decreased the percentage of apoptotic cells caused by t‑BHP, and prevented intracellular reactive oxygen species (ROS) generation in LO2 cells. Furthermore, BA slightly triggered autophagy in LO2 cells, as evidenced by the elevation of LC3‑II expression, while BA combined treatment with an autophagy inhibitor (chloroquine) or activator (rapamycin) did not alter the hepatoprotective properties. In conclusion, BA may possess a hepatoprotective effect against t‑BHP‑induced liver cell injury, dependent on ROS removal. Therefore, BA may represent a potential drug candidate in protecting hepatotoxicity.

Baicalein inhibits tumor progression by inhibiting tumor cell growth and tumor angiogenesis

Baicalein, a herbal medicine, is a natural flavonoid isolated from the roots of Scutellaria baicalensis Georgi. It is known for its anticancer, anti-inflammatory and neuroprotective properties. Despite these well-known properties, it is not yet clear what effect baicalein has on tumor progression. Therefore, in the present study, we used B16F10 cells, Lewis lung carcinoma (LLC) cells, and human umbilical vein endothelial cells (HUVECs) to investigate the effect of baicalein on cell proliferation and viability, migration and tube formation in vitro. In addition, an experimental animal model was used to observe the growth rate and metastasis of tumors and tumor vessel formation in vivo. Our results showed that baicalein decreased the proliferation and migration and induced tumor cell death via caspase-3 activation in the B16F10 and LLC cells, and strongly inhibited tube formation and cell migration in HUVECs. Furthermore, mouse models showed that baicalein reduced the tumor volume and greatly reduced the tumor growth rate in the early stages of tumor progression, and the baicalein-treated groups had significantly reduced expression of CD31 (endothelial cell marker) and α-SMA (mural cell marker) in the tumors, indicating that baicalein inhibits tumor angiogenesis by disrupting tumor vasculature development. Comparison of the lymph node and lung samples collected from the baicalein-treated group, and the untreated group showed that baicalein reduced metastasis of the tumor to these tissues. In summary, baicalein reduced tumor progression and metastasis, directly induced tumor cell death, and inhibited tumor angiogenesis. Our results strongly demonstrate that baicalein is a potential chemotherapeutic agent.

Osimertinib induces autophagy and apoptosis via reactive oxygen species generation in non-small cell lung cancer cells

Osimertinib (OSI), also known as AZD9291, is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has been approved for the treatment of non-small cell lung cancer (NSCLC) patients harboring EGFR T790M mutation. Herein, we indicated for the first time that OSI increased the accumulations of cytoplasmic vacuoles, the expression of phosphatidylethanolamine-modified microtubule-associated protein light-chain 3 (LC3-II), and the formation of GFP-LC3 puncta in various cancer cells. The OSI-induced expression of LC3-II was further increased when combined treatment with chloroquine (CQ), an autophagy inhibitor, and the mRFP-EGFP-LC3 plasmid-transfected cells exposed to OSI led to the production of more red-fluorescent puncta than green-fluorescent puncta, indicating OSI induced autophagic flux in the NSCLC cells. Knockdown of EGFR showed no effect on the OSI-induced expression of LC3-II in NCI-H1975 cells. In addition, OSI increased reactive oxygen species (ROS) generation and scavenge of ROS via pretreatment with N-acetyl-l-cysteine (NAC), catalase (CAT), or vitamin E (Vita E) significantly inhibited OSI-induced the accumulations of cytoplasmic vacuoles, the expression of LC3-II, as well as the formation of GFP-LC3 puncta. Combinative treatment with CQ could not remarkably change the OSI-induced cell viability decrease, whereas the OSI-induced cell viability decrease and apoptosis could be reversed through pretreatment with NAC, CAT, and Vita E, respectively. Taken together, this is the first report that OSI induces an accompanied autophagy and the generation of ROS is critical for the OSI-induced autophagy, cell viability decrease, and apoptosis in NSCLC cells.

Baicalein Induces Beclin 1- and Extracellular Signal-Regulated Kinase-Dependent Autophagy in Ovarian Cancer Cells

Baicalein (BA), one of the major compounds isolated from the root of Scutellaria baicalensis Gerogi, exhibits various pharmacological effects, such as anti-oxidant, anti-inflammatory, and anticancer effects. In this study, we found that BA reduced cell viability and increased apoptosis in ovarian cancer cells. Treatment of cells with BA enhanced microtubule-associated protein light chain 3-II (LC3-II) expression, acidic vesicular organelle and GFP-LC3 fluorescence dot accumulation. Combined treatment with chloroquine and BA apparently reduced cell viability and increased the cleavage of poly (ADPribose) polymerase (PARP) in both HEY and A2780 ovarian cancer cell lines, indicating that BA induces a protective autophagy in these cells. Knockdown of Beclin 1 by siRNA remarkably decreased BA-induced LC3-II lipidation. In addition, we found an increase in the phosphorylation of extracellular signal-regulated kinase (ERK, Thr202/Thr204) and AKT (Ser473) after BA treatment, and inhibition of ERK activation by the pharmacological inhibitor U0126 or ERK siRNA blocked BA-induced autophagy. Taken together, these results suggest that BA induces Beclin 1- and ERK-dependent autophagy in ovarian cancer cells.

Plant Phenols and Autophagy

Many plant phenols (stilbenes, curcumins, catechins, flavonoids, etc.) are effective antioxidants and protect cells during oxidative stress. Extensive clinical studies on the potential of phenolic compounds for treatment of cardiovascular, neurodegenerative, oncological, and inflammatory diseases are now being conducted. In addition to direct antioxidant effect, plant phenols may provide a protective effect via activation of the Keap1/Nrf2/ARE redox-sensitive signaling system and regulation of autophagy. In this review, mechanisms of effects of the most common plant phenols on autophagy are presented.

Fangchinoline accumulates autophagosomes by inhibiting autophagic degradation and promoting TFEB nuclear translocation

Fangchinoline, an alkaloid fromStephania tetrandraS. Moore, accumulates autophagosomes by inhibiting autophagic degradation and promoting TFEB nuclear translocation.

Baicalein attenuates α-synuclein aggregation, inflammasome activation and autophagy in the MPP+-treated nigrostriatal dopaminergic system in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Neuroinflammation, oxidative stress, and protein aggregation form a vicious cycle in the pathophysiology of Parkinson's disease (PD); activated microglia is the main location of neuroinflammation. A Chinese medicine book, "Shanghan Lun", known as the "Treatises on Cold damage Diseases" has suggested that Scutellaria baicalensis Georgi is effective in treating CNS diseases. The anti-inflammatory mechanisms of baicalein, a phenolic flavonoid in the dried root of Scutellaria baicalensis Georgi, remain to be explored.

AIM OF THE STUDY

The neuroprotective mechanisms of baicalein involving α-synuclein aggregation, inflammasome activation, and programmed cell death were investigated in the nigrostriatal dopaminergic system of rat brain in vivo.

MATERIALS AND METHODS

Intranigral infusion of 1-methyl-4-phenylpyridinium (MPP⁺, a Parkinsonian neurotoxin) was performed on anesthetized Sprague-Dawley rats. Baicalein was daily administered via intraperitoneal injection. Striatal dopamine levels were measured using high performance liquid chromatography coupled with electrochemical detection. Cellular signalings were measured by Western blot assay, immunofluorescent staining assay and enzyme-linked immunosorbent assay.

RESULTS

Systemic administration of baicalein attenuated MPP⁺-induced reductions in striatal dopamine content and tyrosine hydroxylase (a biomarker of dopaminergic neurons) in the infused substantia nigra (SN). Furthermore, MPP⁺-induced elevations in α-synuclein aggregates (a pathological hallmark of PD), ED-1 (a biomarker of activated microglia), activated caspase-1 (a proinflammatory caspase), IL-1β and cathepsin B (a cysteine lysosomal protease) in the infused SN were attenuated in the baicalein-treated rats. Moreover, intense immunoreactivities of caspase 1 and cathepsin B were co-localized with that of ED-1 in the MPP⁺-infused SN. At the same time, baicalein inhibited MPP⁺-induced increases in active caspases 9 and 12 (biomarkers of apoptosis) as well as LC3-II levels (a biomarker of autophagy) in the rat nigrostriatal dopaminergic system.

CONCLUSION

Our in vivo study showed that baicalein possesses anti-inflammatory activities by inhibiting α-synuclein aggregation, inflammasome activation and cathepsin B production in the MPP⁺-infused SN. Moreover, baicalein is of therapeutic significance because it inhibits MPP⁺-induced apoptosis and autophagy in the nigrostriatal dopaminergic system of rat brain.

Chikusetsusaponin IVa methyl ester induces G1 cell cycle arrest, triggers apoptosis and inhibits migration and invasion in ovarian cancer cells

BACKGROUND

Panacis Japonici Rhizoma (PJR) is one of the most famous Chinese medical herbs that is known for exhibiting potential anti-cancer effects.

PURPOSE

This study aims to isolate and investigate the anti-cancer potential of saponins from PJR in ovarian cancer cells.

METHODS

The compounds were separated by comprehensive chromatographic methods. By comparison of the 1H- and 13C NMR data, as well as the HR-ESI-MS data, with the corresponding references, the structures of compounds were determined. MTT assay was performed to evaluate cell viability, along with flow cytometry for cell cycle analysis. JC-1 staining, Annexin V-PI double staining as well as Hoechst 33; 342 staining were used for detecting cell apoptosis. Western blot analysis was conducted to determine the relative protein level. Transwell assays were performed to investigate the effect of the saponin on cell migration and invasion and zymography experiments were used to detect the enzymatic activities.

RESULTS

Eleven saponins were isolated from PJR and their anti-proliferative effects were evaluated in human ovarian cancer cells. Chikusetsusaponin IVa methyl ester (1) exhibited the highest anti-proliferative potential among these isolates with the IC50 values at less than 10 µM in both ovarian cancer A2780 and HEY cell lines. Compound 1 induced G1 cell cycle arrest accompanied with an S phase decrease, and down-regulated the expression of cyclin D1, CDK2, and CDK6. Further study showed that compound 1 effectively decreased the cell mitochondrial membrane potential, increased the annexin V positive cells and nuclear chromatin condensation, as well as enhanced the expression of cleaved PARP, Bax and cleaved-caspase 3 while decreasing that of Bcl-2. Moreover, compound 1 suppressed the migration and invasion of HEY and A2780 cells, down-regulated the expression of Cdc42, Rac, RohA, MMP2 and MMP9, and decreased the enzymatic activities of MMP2 and MMP9.

CONCLUSION

These results provide a comprehensive evaluation of compound 1 as a potential agent for the treatment of ovarian cancer.

The Fascinating Effects of Baicalein on Cancer: A Review

Cancer is one of the leading causes of death worldwide and a major global health problem. In recent decades, the rates of both mortality and morbidity of cancer have rapidly increased for a variety of reasons. Despite treatment options, there are serious side effects associated with chemotherapy drugs and multiple forms of drug resistance that significantly reduce their effects. There is an accumulating amount of evidence on the pharmacological activities of baicalein (e.g., anti-inflammatory, antioxidant, antiviral, and antitumor effects). Furthermore, there has been great progress in elucidating the target mechanisms and signaling pathways of baicalein's anti-cancer potential. The anti-tumor functions of baicalein are mainly due to its capacities to inhibit complexes of cyclins to regulate the cell cycle, to scavenge oxidative radicals, to attenuate mitogen activated protein kinase (MAPK), protein kinase B (Akt) or mammalian target of rapamycin (mTOR) activities, to induce apoptosis by activating caspase-9/-3 and to inhibit tumorinvasion and metastasis by reducing the expression of matrix metalloproteinase-2/-9 (MMP-2/-9). In this review, we focused on the relevant biological mechanisms of baicalein involved in inhibiting various cancers, such as bladder cancer, breast cancer, and ovarian cancer. Moreover, we also summarized the specific mechanisms by which baicalein inhibited the growth of various tumors in vivo. Taken together, baicalein may be developed as a potential, novel anticancer drug to treat tumors.

Glycyrrhetinic acid induces cytoprotective autophagy via the inositol-requiring enzyme 1α-c-Jun N-terminal kinase cascade in non-small cell lung cancer cells

Glycerrhetinic acid (GA), one of the main bioactive constituents of Glycyrrhiza uralensis Fisch, exerts anti-cancer effects on various cancer cells. We confirmed that GA inhibited cell proliferation and induced apoptosis in non-small cell lung cancer A549 and NCI-H1299 cells. GA also induced expression of autophagy marker phosphatidylethanolamine-modified microtubule-associated protein light-chain 3 (LC3-II) and punta formation of green fluorescent protein microtubule-associated protein light-chain 3. We further proved that expression of GA-increased autophagy marker was attributed to activation instead of suppression of autophagic flux. The c-jun N-terminal kinase (JNK) pathway was activated after incubation with GA. Pretreatment with the JNK inhibitor SP600125 or silencing of the JNK pathway by siRNA of JNK or c-jun decreased GA-induced autophagy. The endoplasmic reticulum (ER) stress responses were also apparently stimulated by GA by triggering the inositol-requiring enzyme 1α (IRE1α) pathway. The GA-induced JNK pathway activation and autophagy were decreased by IRE1α knockdown, and inhibition of autophagy or the JNK cascade increased GA-stimulated IRE1α expression. In addition, GA-induced cell proliferative inhibition and apoptosis were increased by inhibition of autophagy or the JNK pathway. Our study was the first to demonstrate that GA induces cytoprotective autophagy in non-small cell lung cancer cells by activating the IRE1α-JNK/c-jun pathway. The combined treatment of autophagy inhibitors markedly enhances the anti-neoplasmic activity of GA. Such combination shows potential as a strategy for GA or GA-contained prescriptions in cancer therapy.

Targeting endoplasmic reticulum stress in liver disease

INTRODUCTION

The accumulation of unfolded protein in the endoplasmic reticulum (ER) initiates an unfolded protein response (UPR) via three signal transduction cascades, which involve protein kinase RNA-like ER kinase (PERK), inositol requiring enzyme-1α (IRE1α) and activating transcription factor-6α (ATF6α). An ER stress response is observed in nearly all physiologies related to acute and chronic liver disease and therapeutic targeting of the mechanisms implicated in UPR signaling have attracted considerable attention.

AREAS COVERED

This review focuses on the correlation between ER stress and liver disease and the possible targets which may drive the potential for novel therapeutic intervention. Expert Commentary: We describe pathways which are involved in UPR signaling and their potential correlation with various liver diseases and underlying mechanisms which may present opportunities for novel therapeutic strategies are discussed.

Overview of Oroxylin A: A Promising Flavonoid Compound

Oroxylin A is one of the main active components extracted from Scutellariae radix. It has been proved that oroxylin A possesses a broad spectrum of pharmacological functions, including anti-cancer, antiinflammation, neuroprotective, anti-coagulation and so on. The pharmacological activity of oroxylin A has been studied in vitro and on animal models, which reflected its promising potency in disease treatment. This review aims to recapitulate the pharmacological function and the molecular mechanisms of oroxylin A, as well as its sources, extraction, synthesis and toxicity study. These data confirmed the therapeutic potential of oroxylin A and provided reference for further development. Copyright © 2016 John Wiley & Sons, Ltd.

Herbal Medicine Offered as an Initiative Therapeutic Option for the Management of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common malignant cancer and is the third leading cause of death worldwide. Effective treatment of this disease is limited by the complicated molecular mechanism underlying HCC pathogenesis. Thus, therapeutic options for HCC management are urgently needed. Targeting the Wnt/β-catenin, Hedgehog, Notch, and Hippo-YAP signaling pathways in cancer stem cell development has been extensively investigated as an alternative treatment. Herbal medicine has emerged as an initiative therapeutic option for HCC management because of its multi-level, multi-target, and coordinated intervention effects. In this article, we summarized the recent progress and clinical benefits of targeting the above mentioned signaling pathways and using natural products such as herbal medicine formulas to treat HCC. Proving the clinical success of herbal medicine is expected to deepen the knowledge on herbal medicine efficiency and hasten the adoption of new therapies. Copyright © 2016 John Wiley & Sons, Ltd.

Novel Investigations of Flavonoids as Chemopreventive Agents for Hepatocellular Carcinoma

We would like to highlight the application of natural products to hepatocellular carcinoma (HCC). We will focus on the natural products known as flavonoids, which target this disease at different stages of hepatocarcinogenesis. In spite of the use of chemotherapy and radiotherapy in treating HCC, patients with HCC still face poor prognosis because of the nature of multidrug resistance and toxicity derived from chemotherapy and radiotherapy. Flavonoids can be found in many vegetables, fruits, and herbal medicines that exert their different anticancer effects via different intracellular signaling pathways and serve as antioxidants. In this review, we will discuss seven common flavonoids that exert different biological effects against HCC via different pathways.