AKT serine/threonine protein kinase modulates baicalin-triggered autophagy in human bladder cancer T24 cells

Protective Effect of Baicalin on Chlorpyrifos-Induced Liver Injury and Its Mechanism

Chlorpyrifos (CPF) plays a vital role in the control of various pests in agriculture and household life, even though some studies have indicated that CPF residues pose a significant risk to human health. Baicalin (BA) is a flavonoid drug with an obvious effect on the prevention and treatment of liver diseases. In this study, the protective effect of BA in vitro and in vivo was investigated by establishing a CPF-induced AML12 cell damage model and a CPF-induced Kunming female mouse liver injury model. The AML12 cell damage model indicated that BA had a good positive regulatory effect on various inflammatory factors, redox indexes, and abnormal apoptosis factors induced by CPF. The liver injury model of female mice in Kunming showed that BA significantly improved the liver function indexes, inflammatory response, and fibrosis of mice. In addition, BA alleviated CPF-induced AML12 cell damage and Kunming female mouse liver injury by enhancing autophagy and regulating apoptosis pathways through Western blotting. Collectively, these data suggest that the potential mechanism of BA is a multi-target and multi-channel treatment for chlorpyrifos-induced liver injury.

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 Induction by Scutellaria Flavones in Cancer: Recent Advances

In parallel with a steady rise in cancer incidence worldwide, the scientific community is increasingly focused on finding novel, safer and more efficient modalities for managing this disease. Over the past decades, natural products have been described as a significant source of new structural leads for novel drug candidates. Scutellaria root is one of the most studied natural products because of its anticancer potential. Besides just describing the cytotoxic properties of plant constituents, their molecular mechanisms of action in different cancer types are equally important. Therefore, this review article focuses on the role of the Scutellaria flavones wogonin, baicalein, baicalin, scutellarein and scutellarin in regulating the autophagic machinery in diverse cancer models, highlighting these molecules as potential lead compounds for the fight against malignant neoplasms. The knowledge that autophagy can function as a dual-edged sword, acting in both a pro- and antitumorigenic manner, further complicates the issue, revealing an amazing property of flavonoids that behave either as anti- or proautophagic agents.

Crosstalk between xanthine oxidase (XO) inhibiting and cancer chemotherapeutic properties of comestible flavonoids- a comprehensive update

Gout is an inflammatory disease caused by metabolic disorder or genetic inheritance. People throughout the world are strongly dependent on ethnomedicine for the treatment of gout and some receive satisfactory curative treatment. The natural remedies as well as established drugs derived from natural sources or synthetically made exert their action by mechanisms that are closely associated with anticancer treatment mechanisms regarding inhibition of xanthine oxidase, feedback inhibition of de novo purine synthesis, depolymerization and disappearance of microtubule, inhibition of NF-ĸB activation, induction of TRAIL, promotion of apoptosis, and caspase activation and proteasome inhibition. Some anti-gout and anticancer novel compounds interact with same receptors for their action, e.g., colchicine and colchicine analogues. Dietary flavonoids, i.e., chrysin, kaempferol, quercetin, fisetin, pelargonidin, apigenin, luteolin, myricetin, isorhamnetin, phloretinetc etc. have comparable IC₅₀ values with established anti-gout drug and effective against both cancer and gout. Moreover, a noticeable number of newer anticancer compounds have already been isolated from plants that have been using by local traditional healers and herbal practitioners to treat gout. Therefore, the anti-gout plants might have greater potentiality to become selective candidates for screening of newer anticancer leads.

Baicalin suppresses the migration and invasion of breast cancer cells via the TGF-β/lncRNA-MALAT1/miR-200c signaling pathway

Metastasis is the major cause of death and failure of cancer chemotherapy in patients with breast cancer (BC). Activation of TGF-β/lncRNA-MALAT1/miR-200c has been reported to play an essential role during the metastasis of BC cells. The present study aimed to validate the suppression of BC-cell migration and invasion by baicalin and explore its regulatory effects on the TGF-β/lncRNA-MALAT1/miR-200c signaling pathway. We found that baicalin treatment inhibited cell viability and migration and invasion. Mechanistically, baicalin treatment significantly downregulated the expression of TGF-β, ZEB1, and N-cadherin and upregulated E-cadherin on both mRNA and protein levels. Additionally, baicalin treatment significantly downregulated the expression of lncRNA-MALAT1 and upregulated that of miR-200c. Collectively, baicalin significantly suppresses cell viability, migration, and invasion of BC cells possibly by regulating the TGF-β/lncRNA-MALAT1/miR-200c pathway.

Folic Acid Decorated Zeolitic Imidazolate Framework (ZIF-8) Loaded with Baicalin as a Nano-Drug Delivery System for Breast Cancer Therapy

Background

Baicalin (BAN) has attracted widespread attention due to its low-toxicity and efficient antitumor activity, but its poor water solubility and low bioavailability severely limit its clinical application. Development of a targeted drug delivery system is a good strategy to improve the antitumor activity of baicalin.

Methods

We prepared a BAN nano-drug delivery system PEG-FA@ZIF-8@BAN with a zeolite imidazole framework-8 (ZIF-8) as a carrier, which can achieve the response of folate receptor (FR). We characterized this system in terms of morphology, particle size, zeta-potential, infrared (IR), ultraviolet (UV), x-ray diffraction (XRD), and Brunel-Emmett-Teller (BET), and examined the in vitro cytotoxicity and cellular uptake properties of PEG-FA@ZIF-8@BAN using MCF-7 cells. Lastly, we established a 4T1 tumor-bearing mouse model and evaluated its in vivo anti-mammary cancer activity.

Results

The PEG-FA@ZIF-8@BAN nano-delivery system had good dispersion with a BAN loading efficiency of 41.45 ± 1.43%, hydrated particle size of 176 ± 8.1 nm, Zeta-potential of −23.83 ± 1.1 mV, and slow and massive drug release in an acidic environment (pH 5.0), whereas release was 11.03% in a neutral environment (pH 7.4). In vitro studies showed that PEG-FA@ZIF-8@BAN could significantly enhance the killing effect of BAN on MCF-7 cells, and the folic acid-mediated targeting could lead to better uptake of nanoparticles by tumor cells and thus better killing of cancer cells. In vivo studies also showed that PEG-FA@ZIF-8@BAN significantly increased the inhibition of the proliferation of solid breast cancer tumors (p < 0.01 or p < 0.001).

Conclusion

The PEG-FA@ZIF-8@BAN nano-drug delivery system significantly enhanced the anti-breast cancer effect of baicalin both in vivo and in vitro, providing a more promising drug delivery system for the clinical applications and tumor management.

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.

Baicalin induces ferroptosis in bladder cancer cells by downregulating FTH1

Ferroptosis is a non-apoptotic regulated cell death caused by iron accumulation and subsequent lipid peroxidation. Currently, the therapeutic role of ferroptosis on cancer is gaining increasing interest. Baicalin an active component in Scutellaria baicalensis Georgi with anticancer potential various cancer types; however, the effects of baicalein on bladder cancer and the underlying molecular mechanisms remain largely unknown. In the study, we investigated the effect of baicalin on bladder cancer cells 5637 and KU-19-19. As a result, we show baicalin exerted its anticancer activity by inducing apoptosis and cell death in bladder cancer cells. Subsequently, we for the first time demonstrate baicalin-induced ferroptotic cell death in vitro and in vivo, accompanied by reactive oxygen species (ROS) accumulation and intracellular chelate iron enrichment. The ferroptosis inhibitor deferoxamine but not necrostatin-1, chloroquine (CQ), N-acetyl-l-cysteine, l-glutathione reduced, or carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]-fluoromethylketone (Z-VAD-FMK) rescued baicalin-induced cell death, indicating ferroptosis contributed to baicalin-induced cell death. Mechanistically, we show that ferritin heavy chain 1 (FTH1) was a key determinant for baicalin-induced ferroptosis. Overexpression of FTH1 abrogated the anticancer effects of baicalin in both 5637 and KU19-19 cells. Taken together, our data for the first time suggest that the natural product baicalin exerts its anticancer activity by inducing FTH1-dependent ferroptosis, which will hopefully provide a prospective compound for bladder cancer treatment.

Natural Phytochemicals in Bladder Cancer Prevention and Therapy

Phytochemicals are natural small-molecule compounds derived from plants that have attracted attention for their anticancer activities. Some phytochemicals have been developed as first-line anticancer drugs, such as paclitaxel and vincristine. In addition, several phytochemicals show good tumor suppression functions in various cancer types. Bladder cancer is a malignant tumor of the urinary system. To date, few specific phytochemicals have been used for bladder cancer therapy, although many have been studied in bladder cancer cells and mouse models. Therefore, it is important to collate and summarize the available information on the role of phytochemicals in the prevention and treatment of bladder cancer. In this review, we summarize the effects of several phytochemicals including flavonoids, steroids, nitrogen compounds, and aromatic substances with anticancer properties and classify the mechanism of action of phytochemicals in bladder cancer. This review will contribute to facilitating the development of new anticancer drugs and strategies for the treatment of bladder cancer using phytochemicals.

Targeting Autophagy as a Strategy for Developing New Vaccines and Host-Directed Therapeutics Against Mycobacteria

Mycobacterial disease is an immense burden worldwide. This disease group includes tuberculosis, leprosy (Hansen's disease), Buruli Ulcer, and non-tuberculous mycobacterial (NTM) disease. The burden of NTM disease, both pulmonary and ulcerative, is drastically escalating globally, especially in developed countries such as America and Australia. Mycobacteria's ability to inhibit or evade the host immune system has contributed significantly to its continued prevalence. Pre-clinical studies have highlighted promising candidates that enhance endogenous pathways and/or limit destructive host responses. Autophagy is a cell-autonomous host defense mechanism by which intracytoplasmic cargos can be delivered and then destroyed in lysosomes. Previous studies have reported that autophagy-activating agents, small molecules, and autophagy-activating vaccines may be beneficial in restricting intracellular mycobacterial infection, even with multidrug-resistant strains. This review will examine how mycobacteria evade autophagy and discusses how autophagy could be exploited to design novel TB treatment strategies, such as host-directed therapeutics and vaccines, against Mycobacterium tuberculosis and NTMs.

Baicalin mediated regulation of key signaling pathways in cancer

Baicalin has been widely investigated against different types of malignancies both at the cellular and molecular levels over the past few years. Due to its remarkable anti-proliferative potential in numerous cancer cell lines, it has created immense interest as a potential chemotherapeutic modality compared to other flavonoids. Thus, this review focuses on the recent accomplishments of baicalin and its limitations in cancer prevention and treatment. Further, combination studies and nanoformulations using baicalin to treat cancer along with the metabolism, bioavailability, toxicity, and pharmacokinetics have been discussed. The present review explains biological source, and anti-proliferative potential of baicalin against cancers including breast, colon, hepatic, leukemia, lung, and skin, as well as the relevant mechanism of action to modulate diverse signaling pathways including apoptosis, cell cycle, invasion, and migration, angiogenesis, and autophagy. The anticancer mechanism of baicalin in orthotropic and xenograft mice models have been deliberated. The combination studies of baicalin in novel therapies as chemotherapeutic adjuvants have also been summarized. The low bioavailability, fast metabolism, and poor solubility, and other significant factors that limit the clinical use of baicalin have been examined as a challenge. The improvement in the pharmacokinetics and pharmacodynamics of baicalin with newer approaches and the gaps are highlighted, which could establish baicalin as an effective and safe compound for cancer treatment as well as help to translate its potential from bench to bedside.

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.

SP600125 enhances C-2-induced cell death by the switch from autophagy to apoptosis in bladder cancer cells

BACKGROUND

A natural compound Jaspine B and its derivative possess potential anti-cancer activities; However, little is known about the underlying mechanism. Here, the role of a new autophagy inducer Jaspine B derivative C-2 in suppressing bladder cancer cells was researched in vitro and in vivo.

METHODS

The underlying mechanisms and anticancer effect of C-2 in bladder cancer cells were investigated by MTT, western blotting, immunoprecipitation and immunofluorescence assays. The key signaling components were investigated by using pharmacological inhibitors or specific siRNAs. In vivo, we designed a C-2 and SP600125 combination experiment to verify the effectiveness of compound.

RESULTS

C-2 exhibits cytotoxic effect on bladder cancer cells, and JNK activated by C-2 triggers autophagy and up-regulates SQSTM1/p62 proteins, contributing to activation of Nrf2 pathway. Utilization of JNK inhibitor SP600125 or knockdown of JNK by siRNA potentiate the cytotoxicity of C-2 through down-regulation of p62 and LC3II proteins and up-regulation of active-Caspase3 proteins, enhance the cell death effect, facilitating the switch from autophagy to apoptosis. In vivo study, C-2 suppresses tumor growth in a xenograft mouse model of EJ cells without observed toxicity. Combined treatment with SP600125 further enhances tumor inhibition of C-2 associated with enhanced activation of caspase3 and reduction of autophagy.

CONCLUSIONS

It reveals a series of molecular mechanisms about SP600125 potentiate the cytotoxicity and tumor inhibition of C-2 in bladder cancer cells through promoting C-2-induced apoptosis, expecting it provides research basis and theoretical support for new drugs development.

Polymeric nanocapsular baicalin: Chemometric optimization, physicochemical characterization and mechanistic anticancer approaches on breast cancer cell lines

Baicalin is a multi-purpose flavonoid known for its anticancer properties, but its application is hindered by its low water solubility and bioavailability. Polymeric nanocapsules were proposed in this work as a promising system for enhancing baicalin delivery, and potentiating its anticancer properties. The characterization of nanocapsules was augmented with chemometric analysis, and the selected formulations were tested on two breast cancer cell lines (MCF-7 and MDA-MB-231), with mechanistic anticancer elucidation using MTT assay, confocal microscopy uptake, flow cytometry, mechanism of cell death, reactive oxygen species production, caspase 3/7 activity and death biomarker expression using quantitative real time PCR. Results showed that baicalin nanocapsules displayed favorable pharmaceutical properties; with the formulation variables affecting their properties elucidated using chemometric factorial analysis. Nanocapsules enhanced the anticancer activity of baicalin up to 216 times for MCF-7 cells and 31 times for MDA-MB-231 after 24 hr incubation. Cellular internalization of the fluorescently labeled nanocapsules was confirmed after 4 hr incubation for both cell lines. Apoptosis was the dominant cell death mechanism, with significant up-regulation of P53 in baicalin nanocapsules treated cells. Data here presented drive to further preclinical studies to investigate the delivery of baicalin polymeric nanocapsules and their anti-cancer activity.

CD44s is a crucial ATG7 downstream regulator for stem-like property, invasion, and lung metastasis of human bladder cancer (BC) cells

Over half a million US residents are suffering with bladder cancer (BC), which costs a total $4 billion in treatment annually. Although recent studies report that autophagy-related gene 7 (ATG7) is overexpressed in BCs, the regulatory effects of ATG7 on cancer stem-like phenotypes and invasion have not been explored yet. Current studies demonstrated that the deficiency of ATG7 by its shRNA dramatically reduced sphere formation and invasion in vitro, as well as lung metastasis in vivo in human invasive BC cells. Further studies indicated that the knockdown of ATG7 attenuated the expression of CD44 standard (CD44s), while ectopic introduction of CD44s, was capable of completely restoring sphere formation, invasion, and lung metastasis in T24T(shATG7) cells. Mechanistic studies revealed that ATG7 overexpression stabilized CD44s proteins accompanied with upregulating USP28 proteins. Upregulated USP28 was able to bind to CD44s and remove the ubiquitin group from CD44s' protein, resulting in the stabilization of CD44s protein. Moreover, ATG7 inhibition stabilized AUF1 protein and thereby reduced tet1 mRNA stability and expression, which was able to demethylate usp28 promoter, reduced USP28 expression, finally promoting CD44s degradation. In addition, CD44s was defined to inhibit degradation of RhoGDIβ, which in turn promotes BC invasion. Our results demonstrate that CD44s is a key ATG7 downstream regulator of the sphere formation, invasion, and lung metastasis of BCs, providing significant insight into understanding the BC invasions, metastasis, and stem-like properties.

Baicalin Protects Mice Brain From Apoptosis in Traumatic Brain Injury Model Through Activation of Autophagy

Autophagy is associated with secondary injury following traumatic brain injury (TBI) and is expected to be a therapeutic target. Baicalin, a neuroprotective agent, has been proven to exert multi-functional bioactive effects in brain injury diseases. However, it is unknown if Baicalin influences autophagy after TBI. In the present study, we aimed to explore the effects that Baicalin had on TBI in a mice model, focusing on autophagy as a potential mechanism. We found that Baicalin administration significantly improved motor function, reduced cerebral edema, and alleviated disruption of the blood-brain barrier (BBB) after TBI in mice. Besides, TBI-induced apoptosis was reversed by Baicalin evidenced by Nissl staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and the level of cleaved caspase-3. More importantly, Baicalin enhanced autophagy by detecting the autophagy markers (LC3, Beclin 1, and p62) using western blot and LC3 immunofluorescence staining, ameliorating mitochondrial apoptotic pathway evidenced by restoration of the TBI-induced translocation of Bax and cytochrome C. However, simultaneous treatment with 3-MA inhibited Baicalin-induced autophagy and abolished its protective effects on mitochondrial apoptotic pathway. In conclusion, we demonstrated that Baicalin enhanced autophagy, ameliorated mitochondrial apoptosis and protected mice brain in TBI mice model.

Baicalin alleviates 6-hydroxydopamine-induced neurotoxicity in PC12 cells by down-regulation of microRNA-192-5p

Parkinson's disease (PD), which is caused by neurodegenerative disorder, has no effective treatment until now. Baicalin was reported to have neuroprotective effects. Hence, we investigated the effects of baicalin on PD in an in vitro cell model by using 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in rat pheochromocytoma PC12 cells. PC12 cells were stimulated by 6-OHDA and were treated with baicalin and/or transfected with miR-192-5p mimic or negative control (NC). Cell viability and apoptosis were examined by Cell Counting Kit-8 assay and Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) analysis, respectively. The expression of p62, ratio of light chain (LC)3-II/LC3-I, miR-192-5p was detected by qRT-PCR. All protein expression levels were analyzed by western blot. We found that 6-OHDA significantly inhibited cell viability, induced apoptosis and autophagy, while baicalin reversed the results led by 6-OHDA. Moreover, baicalin negatively regulated expression of miR-192-5p. Under baicalin treatment, transfection with miR-192-5p mimic decreased cell viability and induced apoptosis and autophagy in 6-OHDA-treated cells compared with NC. In addition, the phosphorylation of phosphatidylinositol 3'-kinase (PI3K) and protein kinase B (AKT) was statistically down-regulated by baicalin then thereafter reversed by miR-192-5p mimic. Baicalin reduced 6-OHDA-induced cell injury through down-regulation of miR-192-5p, as well as regulation of PI3K/AKT and MDM-2/p53 signal pathways.

M2C Polarization by Baicalin Enhances Efferocytosis via Upregulation of MERTK Receptor

Baicalin is the main active ingredient primary isolated from the Chinese herb, Scutellaria baicalensis Georgi. Although baicalin can induce M2 macrophage polarization, we still do not know the subtype of macrophages polarized by baicalin. In this study, we characterized that murine bone marrow derived macrophages induced by M-CSF can be further polarized into M2_C phenotype by baicalin. The signatures of M2_C macrophages for mRNA expression like interferon regulatory factor 4 (IRF4), interleukin-10 (IL-10), MERTK and PTX3 were up-regulated. Moreover, we observed the concomitantly decreasing of tumor necrosis factor alpha (TNF- α ), interferon regulatory factor 5 (IRF5), IL-6. In contrast, M2 macrophages polarized by IL-4 increased gene transcript of arginase-1 (Arg-1) and surface marker of CD206 indicates that their identity as M2_A rather than M2_C subtypes. Interestingly, the phagocytosis as well as efferocytosis activity were significantly enhanced in M2_C macrophage polarized by baicalin and these capacities were associated with the expression of MERTK receptor. Finally, we conclude that baicalin induced M2_C macrophages polarization with both elevations of efferocytosis and anti-inflammatory activity.

New compound ChlA-F induces autophagy-dependent anti-cancer effect via upregulating Sestrin-2 in human bladder cancer

ChlA-F is a novel conformation-derivative of Cheliensisin A, styryl-lactone isolates that show potent anti-tumor potential in vivo and vitro. However, the anti-cancer activity and its potential mechanisms underlying ChlA-F action have never been explored. In the present study, we evaluated the potency of ChlA-F on autophagy-mediated anchorage-independent growth inhibition in human high-grade invasive bladder cancer (BC) cells. We found that ChlA-F treatment significantly inhibited anchorage-independent growth of human BC cells by inducing autophagy in a Sestrin-2 (SESN2)-dependent fashion. Our results revealed that ChlA-F treatment specifically induced SESN2 expression via increasing its transcription and mRNA stability. On one hand, ChlA-F treatment markedly attenuated Dicer protein abundance, in turn abolishing miR-27a maturation and further relieving miR-27a binding directly to SESN2 mRNA 3'UTR, thereby promoting SESN2 mRNA stabilization. On the other hand, ChlA-F treatment promoted Sp1 abundance and consequently mediated SESN2 transcription. These results demonstrate that its activation of the autophagic pathway through specifically promoting SESN2 expression mediates the anti-cancer effect of ChlA-F, which offers insights into the novel anti-cancer effect of ChlA-F on BC, as well as providing therapeutic alternatives against human BC.

β-elemene induced anticancer effect in bladder cancer through upregulation of PTEN and suppression of AKT phosphorylation

Human bladder cancer is one of the most aggressive tumours known and has shown resistance to traditional chemotherapy, which depends heavily on DNA-damaging drugs. β-elemene is one of the least cytotoxic antitumor agents that are extracted from Curcuma aromatica salisb and it exhibits antitumor effects in many carcinomas. β-elemene has attracted the attention of clinicians and scientists worldwide due to its few side effects and limited effect on the bone marrow. However, the antitumor mechanism of β-elemene remains largely unstudied. In the present study, the expression of the AKT serine/threonine kinase (AKT) signaling pathway in bladder cancer and normal bladder tissue was investigated, and the influence of β-elemene on bladder cancer cells and the mechanisms involved were assessed. The results showed that phosphatase and tensin homolog deleted on chromosome ten (PTEN) was downregulated and phosphorylated-AKT (pAKT) was overexpressed in human bladder cancer. β-elemene significantly suppressed the viability of bladder cancer cells, while leaving normal bladder cells unaffected. In addition, there was an increased number of apoptotic bladder cancer cells following β-elemene treatment, and a significant reduction in cell invasion and migration. Subsequent western blot analyses revealed that bladder cancer cells treated with β-elemene had increased PTEN expression and decreased expression of pAKT. Taken together, these results suggest that β-elemene has an antitumor effect in bladder cancer cells through the upregulation of PTEN and suppression of AKT phosphorylation.

The Role of Toll-Like Receptor in Inflammation and Tumor Immunity

Toll-like receptors (TLRs) activation enables host to recognize a large number of pathogen-associated molecule patterns (PAMPs), ignite immune cells to discriminate between self and non-self, and then promote the following innate and adaptive immune responses. Accumulated clinical/preclinical evidences have proven TLRs to be critical role in the autoimmune diseases, including inflammatory and tumor-associated diseases. Activation of TLRs is becoming or has been a target for cancer treatment. It is shown that TLRs can induce preferable anti-tumor effect by eliciting inflammatory cytokines expression and cytotoxic T lymphocytes (CTLs) response. As adjuvant, TLRs agonists can launch a strong immune response to assist cancer radiotherapy and bio-chemotherapy. On the other hand, tumor-associated antigens acting as PAMPs, can also activate TLRs and induce tumor gene-related programmed cell death, including apoptosis, autophagy and programmed necrosis. While there are also arguments that the excessive TLRs expression will promote tumor deterioration in various organisms, as the TLR-induced inflammation will accelerate the cancer cells boost in the tumor microenvironment (TME). However, the effect of TLRs acting on cancers is still not quite clear today. In this review, we will summarize the recent researches of TLRs in cancer treatment and their role in TME, giving a brief overview on future expectation.

Baicalin extracted from Huangqin (Radix Scutellariae Baicalensis) induces apoptosis in gastric cancer cells by regulating B cell lymphoma (Bcl-2)/Bcl-2-associated X protein and activating caspase-3 and caspase-9

OBJECTIVE

To evaluate the effects of baicalin in human gastric cancer cells, including apoptosis-inducing effects, and to investigate its underlying mechanisms of action.

METHODS

Cell proliferation and apoptosis assays were performed to investigate the anti-proliferation effects of baicalin in human gastric cancer BGC-823 and MGC-803 cells. Real time-quantitative polymerase chain reaction and Western blotting analysis were performed to elucidate the molecular mechanisms underlying the anti-tumor properties of baicalin.

RESULTS

In BGC-823 and MGC-803 gastric cancer cells treated with 80, 120, and 160 μmol/L baicalin for 48 h, a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay showed that baicalin significantly inhibited cell proliferation in a dose-dependent manner, while flow cytometric analysis demonstrated that baicalin could induce apoptosis, also in a dose-dependent manner. Moreover, baicalin up-regulated the expression of caspase-3, caspase-9, and B cell lymphoma (Bcl-2)-associated X protein and down-regulated the expression of Bcl-2 at both the mRNA and protein level.

CONCLUSION

Baicalin has potential as a therapeutic agent for gastric cancer by inducing apoptosis in cancer cells.

Anticancer effect of salidroside reduces viability through autophagy/PI3K/Akt and MMP-9 signaling pathways in human bladder cancer cells

Salidroside has a wide range of pharmacological activities, including antitumor, anti-inflammatory, analgesic, antibacterial, antiviral and anti-fertility abilities. In the present study, the effects of salidroside on the viability and apoptosis of bladder cancer cells, and the potential underlying mechanisms, were examined. In the present study, treatment with salidroside reduced cell viability, and induced apoptosis and caspase-9/3 activation in the T24 human bladder carcinoma cell line. Salidroside induced autophagy, promoted the protein expression of nucleoporin p62 and the microtubule-associated proteins 1A/1B light chain 3B, suppressed phosphoinositide 3-kinase (PI3K) and phosphorylated protein kinase B (p-Akt) expression, inhibited matrix metalloproteinase-9 (MMP-9) expression and increased that of Bcl-2-associated X protein, which functions as an apoptosis regulator in T24 cells. In the present study, it was demonstrated that the effect of salidroside reduced the viability and induced the apoptosis of bladder cancer cells through the autophagy/PI3K/Akt and MMP-9 signaling pathways.

Baicalin attenuates liver hypoxia/reoxygenation injury by inducing autophagy

The aim of the present study was to explore the effect of baicalin on liver hypoxia/reoxygenation (H/R) injury and the possible mechanism involved. A cellular H/R model was established and cells were treated with 50, 100 and 200 µmol/l baicalin. Following reoxygenation for 6 h, cell viability, lactate dehydrogenase (LDH), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), caspase 3 and cleaved caspase 3 were assessed. Furthermore, levels of endoplasmic reticulum stress markers binding of immunoglobulin protein (BIP) and CCAAT/enhancer-binding protein homologous protein (CHOP) and autophagy markers microtubule-associated proteins 1A/1B light chain 3B (LC3) and beclin 1 were measured. To confirm the involvement of autophagy in baicalin-mediated attenuation of H/R injury, the autophagy inhibitor 3-methyladenine (3-MA) was administered. The results revealed that baicalin administration increased cell viability and decreased LDH levels, most notably at a dosage of 100 µmol/l. Baicalin pretreatment also downregulated the expression of caspase 3, cleaved caspase 3 and Bax, while upregulating the expression of Bcl-2. Furthermore, BIP and CHOP were decreased while LC3 and beclin-1 were significantly increased by baicalin pretreatment. Inhibiting autophagy using 3-MA, resulted in a significant decrease in LC3-II, beclin-1 and LDH, as well as increase in the expression of BIP, CHOP, caspase 3, cleaved caspase 3 and Bax. Bcl-2 and cell viability were also decreased. In conclusion, the results of the present study indicate that baicalin exerts a protective effect on liver H/R injury and this may be achieved via the induction of autophagy.

TLR2 Regulates Allergic Airway Inflammation and Autophagy Through PI3K/Akt Signaling Pathway

Toll-like receptors (TLRs) are innate pattern recognition receptors that play a critical role in allergic inflammation, yet their contribution to autophagy in asthma remains poorly defined. Here, we investigate the role of Toll-like receptor 2 (TLR2) in phosphoinositide 3-kinases/protein kinase B (PI3K/Akt) pathway-mediated autophagy in ovalbumin-induced airway inflammation in mice. Wild-type (WT) and TLR2-knockout (TLR2^-/-) C57BL/6 mice were ovalbumin-sensitized and ovalbumin-challenged. In ovalbumin-challenged WT mice, enhanced expression of TLR2 in lung tissue, remarkable inflammatory cell infiltrates, goblet cell hyperplasia, and increased mucus production were observed. The number of inflammatory cells and interleukin-13 (IL-13) levels increased, while interferon-gamma (IFN-γ) levels decreased in bronchoalveolar lavage fluid. Expression of PI3K, phospho-Akt, Beclin-1 and LC3-II was enhanced significantly. These changes were mitigated dose-dependently in 3-methyl adenine-treated mice. In contrast, similar but weaker changes were found in ovalbumin-challenged TLR2^-/- mice, and the changes were not significantly attenuated by 3-methyl adenine treatment. These results indicate that TLR2 confers a pivotal role in allergic airway inflammation via regulating the PI3K/Akt signaling pathway-related autophagy in mice.

Antimycobacterial and Anti-inflammatory Mechanisms of Baicalin via Induced Autophagy in Macrophages Infected with Mycobacterium tuberculosis

Tuberculosis (TB) remains a leading killer worldwide among infectious diseases and the effective control of TB is still challenging. Autophagy is an intracellular self-digestion process which has been increasingly recognized as a major host immune defense mechanism against intracellular microorganisms like Mycobacterium tuberculosis (Mtb) and serves as a key negative regulator of inflammation. Clinically, chronic inflammation surrounding Mtb can persist for decades leading to lung injury that can remain even after successful treatment. Adjunct host-directed therapy (HDT) based on both antimycobacterial and anti-inflammatory interventions could be exploited to improve treatment efficacy and outcome. Autophagy occurring in the host macrophages represents a logical host target. Here, we show that herbal medicine, baicalin, could induce autophagy in macrophage cell line Raw264.7 and caused increased killing of intracellular Mtb. Further, baicalin inhibited Mtb-induced NLRP3 inflammasome activation and subsequent inflammasome-derived IL-1β. To investigate the molecular mechanisms of baicalin, the signaling pathways associated with autophagy were examined. Results indicated that baicalin decreased the levels of phosphorylated protein kinase B (p-Akt) and phosphorylated mammalian target of rapamycin (p-mTOR) at Ser473 and Ser2448, respectively, but did not alter the phosphorylation of p38, JNK, or ERK both in Raw264.7 and primary peritoneal macrophages. Moreover, baicalin exerted an obvious inhibitory effect on nuclear factor-kappa B (NF-κB) activity. Finally, immunofluorescence studies demonstrated that baicalin promoted the co-localization of inflammasome with autophagosome may serve as the underlying mechanism of autophagic degradative effect on reducing inflammasome activation. Together, baicalin definitely induces the activation of autophagy on the Mtb-infected macrophages through PI3K/Akt/mTOR pathway instead of MAPK pathway. Furthermore, baicalin inhibited the PI3K/Akt/NF-κB signal pathway, and both autophagy induction and NF-κB inhibition contribute to limiting the NLRP3 inflammasome as well as subsequent production of pro-inflammatory cytokine IL-1β. Based on these results, we conclude that baicalin is a promising antimycobacterial and anti-inflammatory agent which can be a novel candidate for the development of new adjunct drugs targeting HDT for possible improved treatment.

The mechanisms of graphene-based materials-induced programmed cell death: a review of apoptosis, autophagy, and programmed necrosis

Graphene-based materials (GBMs) are widely used in many fields, including biomedicine. To date, much attention had been paid to the potential unexpected toxic effects of GBMs. Here, we review the recent literature regarding the impact of GBMs on programmed cell death (PCD). Apoptosis, autophagy, and programmed necrosis are three major PCDs. Mechanistic studies demonstrated that the mitochondrial pathways and MAPKs (JNK, ERK, and p38)- and TGF-β-related signaling pathways are implicated in GBMs-induced apoptosis. Autophagy, unlike apoptosis and necroptosis which are already clear cell death types, plays a vital pro-survival role in cell homeostasis, so its role in cell death should be carefully considered. However, GBMs always induce unrestrained autophagy accelerating cell death. GBMs trigger autophagy through inducing autophagosome accumulation and lysosome impairment. Mitochondrial dysfunction, ER stress, TLRs signaling pathways, and p38 MAPK and NF-κB pathways participate in GBMs-induced autophagy. Programmed necrosis can be activated by RIP kinases, PARP, and TLR-4 signaling in macrophages after GBMs exposure. Though apoptosis, autophagy, and necroptosis are distinguished by some characteristics, their numerous signaling pathways comprise an interconnected network and correlate with each other, such as the TLRs, p53 signaling pathways, and the Beclin-1 and Bcl-2 interaction. A better understanding of the mechanisms of PCD induced by GBMs may allow for a thorough study of the toxicology of GBMs and a more precise determination of the consequences of human exposure to GBMs. These determinations will also benefit safety assessments of the biomedical and therapeutic applications of GBMs.

YC-1 induces G0/G1 phase arrest and mitochondria-dependent apoptosis in cisplatin-resistant human oral cancer CAR cells

Oral cancer is a serious and fatal disease. Cisplatin is the first line of chemotherapeutic agent for oral cancer therapy. However, the development of drug resistance and severe side effects cause tremendous problems clinically. In this study, we investigated the pharmacologic mechanisms of YC-1 on cisplatin-resistant human oral cancer cell line, CAR. Our results indicated that YC-1 induced a concentration-dependent and time-dependent decrease in viability of CAR cells analyzed by MTT assay. Real-time image analysis of CAR cells by IncuCyte™ Kinetic Live Cell Imaging System demonstrated that YC-1 inhibited cell proliferation and reduced cell confluence in a time-dependent manner. Results from flow cytometric analysis revealed that YC-1 promoted G₀/G₁ phase arrest and provoked apoptosis in CAR cells. The effects of cell cycle arrest by YC-1 were further supported by up-regulation of p21 and down-regulation of cyclin A, D, E and CDK2 protein levels. TUNEL staining showed that YC-1 caused DNA fragmentation, a late stage feature of apoptosis. In addition, YC-1 increased the activities of caspase-9 and caspase-3, disrupted the mitochondrial membrane potential (AYm) and stimulated ROS production in CAR cells. The protein levels of cytochrome c, Bax and Bak were elevated while Bcl-2 protein expression was attenuated in YC-1-treated CAR cells. In summary, YC-1 suppressed the viability of cisplatin-resistant CAR cells through inhibiting cell proliferation, arresting cell cycle at G₀/G₁ phase and triggering mitochondria-mediated apoptosis. Our results provide evidences to support the potentially therapeutic application of YC-1 on fighting against drug resistant oral cancer in the future.

Autophagy and its link to type II diabetes mellitus

Autophagy, a double-edged sword for cell survival, is the research object on 2016 Nobel Prize in Physiology or Medicine. Autophagy is a molecular mechanism for maintaining cellular physiology and promoting survival. Defects in autophagy lead to the etiology of many diseases, including diabetes mellitus (DM), cancer, neurodegeneration, infection disease and aging. DM is a metabolic and chronic disorder and has a higher prevalence in the world as well as in Taiwan. The character of diabetes mellitus is hyperglycemia resulting from defects in insulin secretion, insulin action, or both. Type 2 diabetes mellitus (T2DM) is characterized by insulin resistance and failure of producing insulin on pancreatic beta cells. In T2DM, autophagy is not only providing nutrients to maintain cellular energy during fasting, but also removes damaged organelles, lipids and miss-folded proteins. In addition, autophagy plays an important role in pancreatic beta cell dysfunction and insulin resistance. In this review, we summarize the roles of autophagy in T2DM.

Identification and validation of a novel autophagy gene expression signature for human bladder cancer patients

We sought to identify and validate a novel urinary autophagy transcript signature in patients with bladder cancer and evaluate its clinical utility. We performed an initial screening for seven autophagy transcript-based panel (autophagy-related protein 12 (ATG12); WD repeat domain, phosphoinositide interacting 2 (WIPI2); FYVE and coiled-coil domain-containing protein 1 (FYCO1); microtubule-associated protein light chain (MAPLC3); RB1-inducible coiled-coil 1 (RB1CC1); tachylectin-II-like beta-propeller domain 1 (TECPR1); and Unc-51-like kinase (ULK1)) that was identified based on bioinformatics analysis followed by SYBR Green-based polymerase chain reaction array validation in paired tissue and urine samples. Afterward, we evaluated the expression of differentially expressed autophagy transcripts in an independent validation set with reverse transcription quantitative real-time polymerase chain reaction in urine sediments of 140 patients with bladder cancer, 68 patients with benign urological lesions, and 74 healthy controls (age and sex matched). The expression levels of ATG12, FYCO1, TECPR1, and ULK1 in paired bladder tissue and urine samples were significantly lower in bladder cancer than in control group (p < 0.001). In the validation set, the receiver-operating characteristic curve analyses demonstrated that each urinary autophagy transcripts showed high sensitivity and specificity for distinguishing bladder cancer from non-bladder cancer patients (ATG12, 75.4% and 86.1%; FYCO1, 87% and 75.7%; ULK1, 85.5% and 75.6%; and TECPR1, 90% and 81.9%). We document and validate a novel autophagy transcript signature for human bladder cancer diagnosis: bilharzial and non-bilharzial types.

The formation of a host-guest inclusion complex system between β-cyclodextrin and baicalin and its dissolution characteristics

Objectives

Baicalin (BCL) has potential therapeutic benefits, but its clinical outcomes are restricted mainly because of low water solubility. This study sought to improve the water solubility of BCL by the formation of inclusion complex with β-cyclodextrin (β-CD).

Methods

The inclusion complex was studied by solubility test, differential scanning calorimeter (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), 1H Nuclear magnetic resonance (1HNMR) and scanning electron microscopy (SEM). Molecular docking was conducted to verify the experimental findings. The dissolution rate was determined by dialysis membrane method. In vivo absorption studies in rats were conducted and high-performance liquid chromatography (HPLC) was used to analyse the plasma level of BCL after oral administration.

Key findings

The DSC, FTIR, XRD, 1HNMR and SEM findings suggested the formation of inclusion complex between BCL and β-CD in 1 : 1 stoichiometry. Molecular docking demonstrated the insertion of benzene ring of BCL into β-CD cavity by hydrophobic interactions and possible H-bond formation. Moreover, β-CD markedly improved the solubility of BCL and displayed AL-type phase diagrams. The improvement in dissolution rate of the inclusion complex was reflected in the earlier Tmax, higher Cmax and larger AUC0–t than that of BCL after oral administration.

Conclusions

β-cyclodextrin complex can be used as an effective formulation strategy for development of BCL-loaded delivery system with better therapeutic outcomes.

Autophagy modulators from traditional Chinese medicine: Mechanisms and therapeutic potentials for cancer and neurodegenerative diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM), an ancient yet still alive medicinal system widely used in East Asia, has played an essential role in health maintenance and diseases control, for a wide range of human chronic diseases like cancers and neurodegenerative diseases. TCM-derived compounds and extracts attract wide attention for their potential application as therapeutic agents against above mentioned diseases.

AIM OF REVIEW

Recent years the enthusiasm in searching for autophagy regulators for human diseases has yielded many positive hits. TCM-derived compounds as important sources for drug discovery have been widely tested in different models for autophagy modulation. Here we summarize the current progress in the discovery of natural autophagy regulators from TCM for the therapeutic application in cancer and neurodegenerative disease models, aiming to provide the direct link from traditional use to new pharmacological application.

METHODS

The present review collected the literature published during the recent 10 years which studied the effect of TCM-derived compounds or extracts on autophagy regulation from PubMed, Web of Science, Google Scholar and Science Direct. The names of chemical compounds studied in this article are corresponding to the information in journal plant list.

RESULTS

In this review, we give a brief introduction about the autophagy and its roles in cancer and neurodegenerative disease models and describe the molecular mechanisms of autophagy modulation. We also make comprehensive lists to summarize the effects and underlying mechanisms of TCM-derived autophagy regulators in cancer and neurodegenerative disease models. In the end of the review, we discuss the current strategies, problems and future direction for TCM-derived autophagy regulators in the treatment of human diseases.

CONCLUSIONS

A number of data from in vivo and in vitro models indicated TCM derived compounds and extracts hold great potential for the treatment of human diseases including cancers and neurodegenerative diseases. Autophagy, as a novel and promising drug target involved in a wide range of human diseases, can be modulated by many TCM derived agents, indicating autophagy modulation may be an important mechanism underlying the therapeutic effect of TCM in treating diseases. Furthermore, we look forward to seeing the discovery of ideal autophagy modulators from TCM with considerably higher selectivity for the treatment of human diseases.

Functional Role and Mechanism of microRNA-28b in Atrial Myocyte in a Persistent Atrial Fibrillation Rat Model

Background

Persistent atrial fibrillation has been indicated to be related with microRNA-28b. However, the exact role of microRNA-28b in persistent atrial fibrillation needs to be further elucidated. Therefore, this study aimed to establish a rat model of persistent atrial fibrillation to investigate the level of microRNA-28b in atrial myocytes and to explore the molecular mechanism involved.

Material/Methods

A persistent atrial fibrillation model was established in rats by using chronic rapid atrial pacing induction. The size of the heart was measured by ultrasonic method. The expression of microRNA-28b in left atrial myocytes was quantified by RT-PCR. Cardiomyocytes were isolated and cultured to detect cell proliferation and apoptosis by MTT and flow cytometry, respectively. The specific inhibitor of ERK signaling pathway, PD98059, was used to further illustrate the role of ERK signaling pathway in the modulation of cardiomyocytes in persistent atrial fibrillation.

Results

MicroRNA-28b was up-regulated in the experimental rat model with persistent atrial fibrillation. The proliferation of cardiomyocytes was significantly inhibited with potentiated apoptosis. Blockage of the ERK pathway suppressed the microRNA-28b expression and inhibited cell apoptosis.

Conclusions

microRNA-28b-induced growth inhibition and cell apoptosis of atrial myocytes was observed in the rat model with persistent atrial fibrillation, via activation of the ERK signaling pathway.

Oleuropein Prevents Neuronal Death, Mitigates Mitochondrial Superoxide Production and Modulates Autophagy in a Dopaminergic Cellular Model

Parkinson’s disease (PD) is a progressive neurodegenerative disorder, primarily affecting dopaminergic neurons in the substantia nigra. There is currently no cure for PD and present medications aim to alleviate clinical symptoms, thus prevention remains the ideal strategy to reduce the prevalence of this disease. The goal of this study was to investigate whether oleuropein (OLE), the major phenolic compound in olive derivatives, may prevent neuronal degeneration in a cellular dopaminergic model of PD, differentiated PC12 cells exposed to the potent parkinsonian toxin 6-hydroxydopamine (6-OHDA). We also investigated OLE’s ability to mitigate mitochondrial oxidative stress and modulate the autophagic flux. Our results obtained by measuring cytotoxicity and apoptotic events demonstrate that OLE significantly decreases neuronal death. OLE could also reduce mitochondrial production of reactive oxygen species resulting from blocking superoxide dismutase activity. Moreover, quantification of autophagic and acidic vesicles in the cytoplasm alongside expression of specific autophagic markers uncovered a regulatory role for OLE against autophagic flux impairment induced by bafilomycin A1. Altogether, our results define OLE as a neuroprotective, anti-oxidative and autophagy-regulating molecule, in a neuronal dopaminergic cellular model.

The Extraction, Anticancer Effect, Bioavailability, and Nanotechnology of Baicalin

The dried root of Baikal skullcap (Scutellaria baicalensis) has been historically and widely used in traditional Eastern medicine. Modern science proved that baicalin is the major bioactive responsible for the physiological activity of Baikal skullcap. Baicalin, a flavonoid found in several species in the genus Scutellaria, has been regarded as a potent anticancer agent. In this review, we present the main extraction methods, anticancer activity and bioavailability of baicalin. Besides, the utilization of nanotechnology to improve the bioavailability of baicalin is also mentioned.

Goniothalamin induces apoptosis associated with autophagy activation through MAPK signaling in SK-BR-3 cells

Goniothalamin, a plant bioactive styrly-lactone, possesses many biological activities. In the present study, the anticancer effect of goniothalamin on human breast cancer cell line SK-BR-3 was investigated. The results showed that goniothalamin induced nuclear condensation, DNA fragmentation, apoptotic bodies and mitochondrial dysfunction as determined by JC-1 staining. Goniothalamin also increased the Bax/Bcl-2 ratio and expression of cleaved caspase-7, cleaved caspase-9 and cleaved PARP, but decreased Bcl-2 expression. In addition, goniothalamin induced apoptosis via p-JNK1/2 and p-p38 upregulation and inhibited cell survival via p-ERK1/2 and p-Akt downregulation. Notably, goniothalamin induced autophagy through upregulation of Atg7, Atg12-Atg5 conjugation and LC3II. The increased p-p38 and p-JNK1/2 and decreased p-Akt may lead to autophagy induction. Therefore, goniothalamin promoted apoptosis associated with autophagy induction in SK-BR-3 cells through p-p38 and p-JNK1/2 upregulation and p-Akt downregulation. The present study indicated that goniothalamin may be further used as a potential therapeutic candidate or may offer an alternative treatment for breast cancer.

Endoplasmic reticulum stress contributes to arsenic trioxide-induced intrinsic apoptosis in human umbilical and bone marrow mesenchymal stem cells

Arsenic trioxide is an old drug and has been used for a long time in traditional Chinese and Western medicines. However, the cancer treatment of arsenic trioxide has heart and vascular toxicity. The cytotoxic effects of arsenic trioxide and its molecular mechanism in human umbilical mesenchymal stem cells (HUMSC) and human bone marrow-derived mesenchymal stem cells (HMSC-bm) were investigated in this study. Our results showed that arsenic trioxide significantly reduced the viability of HUMSC and HMSC-bm in a concentration- and time-dependent manner. Arsenic trioxide is able to induce apoptotic cell death in HUMSC and HMSC-bm, as shown from the results of morphological examination, flow cytometric analyses, DAPI staining and comet assay. The appearance of arsenic trioxide also led to an increase of intracellular free calcium (Ca(2+) ) concentration and the disruption of mitochondrial membrane potential (ΔΨm). The caspase-9 and caspase-3 activities were time-dependently increased in arsenic trioxide-treated HUMSC and HMSC-bm. In addition, the proteomic analysis and DNA microarray were carried out to investigate the expression level changes of genes and proteins affected by arsenic trioxide treatment in HUMSC. Our results suggest that arsenic trioxide induces a prompt induction of ER stress and mitochondria-modulated apoptosis in HUMSC and HMSC-bm. A framework was proposed for the effect of arsenic trioxide cytotoxicity by targeting ER stress.

Recent highlights of experimental research for inhibiting tumor growth by using Chinese medicine

To give an overview of contemporary experimental research using Chinese medicine (CM) for the treatment of cancer. As an integral part of mainstream medicine in the People's Republic of China, CM emphasizes improvements in holistic physical condition instead of merely killing tumor cells, which is consistent with the current medical model that advocates patient-oriented treatment. Great progress has been made in experimental research, and the principle aspects include anti-tumor angiogenesis, inducing apoptosis and differentiation, reversing multidrug resistance, and improving immune function. As a current hot topic in cancer research, tumor microenvironment (TME) highlights the mutual and interdependent interaction between tumor cells and their surrounding tissues, and the CM treatment concept bears a striking resemblance to it. To date, primary points of TME include extracellular matrix remodeling, inflammation, hypoxia, and angiogenesis, but trials using CM with a focus on TME are rare. Despite considerable recent development, experimental research on CM for solving cancer issues appears insufficient. Greater efforts in this field are urgently needed.

Inhibition of High Basal Level of Autophagy Induces Apoptosis in Human Bladder Cancer Cells

PURPOSE

Cancer cells adapt to stress by activation of the autophagy pathway primed for survival. A high basal level of autophagic activity was found in human bladder cancer cell lines. We studied the significance of the phenomenon on cancer cell survival.

MATERIALS AND METHODS

The immortalized human bladder epithelial cell line SV-HUC-1 and the human bladder cancer cell lines RT-4 and 5637 together with human bladder cancer specimens collected from patients were used. A commercially available bladder cancer microarray was applied to confirm the findings. LC3 (light chain-3) II protein detection was done to determine the presence of autophagy. Caspase 3 and DNA fragmentation was performed to detect apoptosis.

RESULTS

Bladder cancer cell lines showed activated autophagic flux compared to SV-HUC-1 cells, prostate cancer cells and breast cancer cells. Results were confirmed in human bladder cancer specimens. Autophagy inhibition by Baf (bafilomycin) A1, or by knockdown of ATG (autophagy related protein) 7 or 12 induced cytotoxicity in multiple human bladder cell lines. Induction of apoptosis was found in cells with autophagy inhibition. Although the disruption of mitochondria membrane potential or the generation of reactive oxygen species was detected in Baf A1 treated cells, intensity was mild and not thought to be related to apoptosis of bladder cancer cells.

CONCLUSIONS

Our results indicate that autophagy is required for the growth and survival of human bladder cancer cells.

Autophagy-induced RelB/p52 activation mediates tumour-associated macrophage repolarisation and suppression of hepatocellular carcinoma by natural compound baicalin

The plasticity of tumour-associated macrophages (TAMs) has implicated an influential role in hepatocellular carcinoma (HCC). Repolarisation of TAM towards M1 phenotype characterises an immune-competent microenvironment that favours tumour regression. To investigate the role and mechanism of TAM repolarisation in suppression of HCC by a natural compound baicalin, Orthotopic HCC implantation model was used to investigate the effect of baicalin on HCC; liposome-clodronate was introduced to suppress macrophage populations in mice; bone marrow-derived monocytes (BMDMs) were induced to unpolarised, M1-like, M2-like macrophages and TAM using different conditioned medium. We observed that oral administration of baicalin (50 mg/kg) completely blocked orthotopic growth of implanted HCC. Suppression of HCC by baicalin was diminished when mice macrophage was removed by clodronate treatment. Baicalin induced repolarisation of TAM to M1-like phenotype without specific toxicity to either phenotype of macrophages. Baicalin initiated TAM reprogramming to M1-like macrophage, and promoted pro-inflammatory cytokines production. Co-culturing of HCC cells with baicalin-treated TAMs resulted in reduced proliferation and motility in HCC. Baicalin had minimal effect on derivation of macrophage polarisation factors by HCC cells, while directly induced repolarisation of TAM and M2-like macrophage. This effect was associated with elevated autophagy, and transcriptional activation of RelB/p52 pathway. Suppression of autophagy or RelB abolished skewing of baicalin-treated TAM. Autophagic degradation of TRAF2 in baicalin-treated TAM might be responsible for RelB/p52 activation. Our findings unveil the essential role of TAM repolarisation in suppressive effect of baicalin on HCC, which requires autophagy-associated activation of RelB/p52.

Colon cancer chemopreventive effects of baicalein, an active enteric microbiome metabolite from baicalin

Baicalin is a major constituent of Scutellaria baicalensis, which is a commonly used herbal medicine in many Asian countries. After oral ingestion, intestinal microbiota metabolism may change parent compound's structure and its biological activities. However, whether baicalin can be metabolized by enteric microbiota and the related anticancer activity is not clear. In this study, using human enteric microbiome incubation and HPLC analysis, we observed that baicalin can be quickly converted to baicalein. We compared the antiproliferative effects of baicalin and baicalein using a panel of human cancer cell lines, including three human colorectal cancer (CRC) cell lines. In vitro antiproliferative effects on CRC cells were verified using an in vivo xenograft nude mouse model. Baicalin showed limited antiproliferative effects on some of these cancer cell lines. Baicalein, however, showed significant antiproliferative effects in all the tested cancer cell lines, especially on HCT-116 human colorectal cancer cells. In vivo antitumor results supported our in vitro data. We demonstrated that baicalein exerts potent S phase cell cycle arrest and pro-apoptotic effects in HCT-116 cells. Baicalein induced the activation of caspase 3 and 9. The in silico modeling suggested that baicalein forms hydrogen bonds with residues Ser251 and Asp253 at the active site of caspase 3, while interactions with residues Leu227 and Asp228 in caspase 9 through its hydroxyl groups. Data from this study suggested that baicalein is a potent anticancer metabolite derived from S. baicalensis. Enteric microbiota play a key role in the colon cancer chemoprevention of S. baicalensis.

Anti-cancer Effect of Luminacin, a Marine Microbial Extract, in Head and Neck Squamous Cell Carcinoma Progression via Autophagic Cell Death

PURPOSE

The purpose of this study is to determine whether luminacin, a marine microbial extract from the Streptomyces species, has anti-tumor effects on head and neck squamous cell carcinoma (HNSCC) cell lines via autophagic cell death.

MATERIALS AND METHODS

Inhibition of cell survival and increased cell death was measured using cell viability, colony forming, and apoptosis assays. Migration and invasion abilities of head and cancer cells were evaluated using wound healing, scattering, and invasion assays. Changes in the signal pathway related to autophagic cell death were investigated. Drug toxicity of luminacin was examined in in vitro HaCaT cells and an in vivo zebrafish model.

RESULTS

Luminacin showed potent cytotoxicity in HNSCC cells in cell viability, colony forming, and fluorescence-activated cell sorting analysis. In vitro migration and invasion of HNSCC cells were attenuated by luminacin treatment. Combined with Beclin-1 and LC3B, Luminacin induced autophagic cell death in head and neck cancer cells. In addition, in a zebrafish model and human keratinocyte cell line used for toxicity testing, luminacin treatment with a cytotoxic concentration to HNSCC cells did not cause toxicity.

CONCLUSION

Taken together, these results demonstrate that luminacin induces the inhibition of growth and cancer progression via autophagic cell death in HNSCC cell lines, indicating a possible alternative chemotherapeutic approach for treatment of HNSCC.

Elaborating the role of natural products-induced autophagy in cancer treatment: achievements and artifacts in the state of the art

Autophagy is a homeostatic process that is highly conserved across different types of mammalian cells. Autophagy is able to relieve tumor cell from nutrient and oxidative stress during the rapid expansion of cancer. Excessive and sustained autophagy may lead to cell death and tumor shrinkage. It was shown in literature that many anticancer natural compounds and extracts could initiate autophagy in tumor cells. As summarized in this review, the tumor suppressive action of natural products-induced autophagy may lead to cell senescence, provoke apoptosis-independent cell death, and complement apoptotic cell death by robust or target-specific mechanisms. In some cases, natural products-induced autophagy could protect tumor cells from apoptotic death. Technical variations in detecting autophagy affect data quality, and study focus should be made on elaborating the role of autophagy in deciding cell fate. In vivo study monitoring of autophagy in cancer treatment is expected to be the future direction. The clinical-relevant action of autophagy-inducing natural products should be highlighted in future study. As natural products are an important resource in discovery of lead compound of anticancer drug, study on the role of autophagy in tumor suppressive effect of natural products continues to be necessary and emerging.

Cucurbitacin E has neuroprotective properties and autophagic modulating activities on dopaminergic neurons

Natural molecules are under intensive study for their potential as preventive and/or adjuvant therapies for neurodegenerative disorders such as Parkinson's disease (PD). We evaluated the neuroprotective potential of cucurbitacin E (CuE), a tetracyclic triterpenoid phytosterol extracted from the Ecballium elaterium (Cucurbitaceae), using a known cellular model of PD, NGF-differentiated PC12. In our postmitotic experimental paradigm, neuronal cells were treated with the parkinsonian toxin 1-methyl-4-phenylpyridinium (MPP⁺) to provoke significant cellular damage and apoptosis or with the potent N,N-diethyldithiocarbamate (DDC) to induce superoxide (O₂^•−) production, and CuE was administered prior to and during the neurotoxic treatment. We measured cellular death and reactive oxygen species to evaluate the antioxidant and antiapoptotic properties of CuE. In addition, we analyzed cellular macroautophagy, a bulk degradation process involving the lysosomal pathway. CuE showed neuroprotective effects on MPP⁺-induced cell death. However, CuE failed to rescue neuronal cells from oxidative stress induced by MPP⁺ or DDC. Microscopy and western blot data show an intriguing involvement of CuE in maintaining lysosomal distribution and decreasing autophagy flux. Altogether, these data indicate that CuE decreases neuronal death and autophagic flux in a postmitotic cellular model of PD.

The novel pterostilbene derivative ANK-199 induces autophagic cell death through regulating PI3 kinase class III/beclin 1/Atg‑related proteins in cisplatin‑resistant CAR human oral cancer cells

Pterostilbene is an effective chemopreventive agent against multiple types of cancer cells. A novel pterostilbene derivative, ANK-199, was designed and synthesized by our group. Its antitumor activity and mechanism in cisplatin-resistant CAR human oral cancer cells were investigated in this study. Our results show that ANK-199 has an extremely low toxicity in normal oral cell lines. The formation of autophagic vacuoles and acidic vesicular organelles (AVOs) was observed in the ANK-199-treated CAR cells by monodansylcadaverine (MDC) and acridine orange (AO) staining, suggesting that ANK-199 is able to induce autophagic cell death in CAR cells. Neither DNA fragmentation nor DNA condensation was observed, which means that ANK-199-induced cell death is not triggered by apoptosis. In accordance with morphological observation, 3-MA, a specific inhibitor of PI3K kinase class III, can inhibit the autophagic vesicle formation induced by ANK-199. In addition, ANK-199 is also able to enhance the protein levels of autophagic proteins, Atg complex, beclin 1, PI3K class III and LC3-II, and mRNA expression of autophagic genes Atg7, Atg12, beclin 1 and LC3-II in the ANK-199-treated CAR cells. A molecular signaling pathway induced by ANK-199 was therefore summarized. Results presented in this study show that ANK-199 may become a novel therapeutic reagent for the treatment of oral cancer in the near future (patent pending).

Curcumin-loaded nanoparticles enhance apoptotic cell death of U2OS human osteosarcoma cells through the Akt-Bad signaling pathway

Curcumin has potential anticancer activity and has been shown to be involved in several signaling pathways including differentiation and apoptosis. Our previous study showed that water-soluble PLGA curcumin nanoparticles (Cur-NPs) triggered apoptotic cell death through regulation of the function of MDR1 and the production of reactive oxygen species (ROS) in cisplatin-resistant human oral cancer CAR cells. In this study, we investigated the anti-proliferative effects of Cur-NPs on human osteosarcoma U2OS cells. The morphology of Cur-NPs showed spherical shape by TEM analysis. The encapsulation efficiency of curcumin in Cur-NPs prepared by single emulsion was 90.5 ± 3.0%. Our results demonstrated that the curcumin fragments on the mass spectrum of Cur-NPs and the peaks of curcumin standard could be found on the Cur-NPs spectrum by 1H-NMR spectra analysis. Cur-NPs induced anti-proliferative effects and apoptosis in U2OS cells. Compared to the untreated U2OS cells, more detectable amount of Cur-NPs was found inside the treated U2OS cells. Cur-NPs induced DNA fragmentation and apoptotic bodies in U2OS cells. Both the activity and the expression levels of caspases-3/-7 and caspase-9 were elevated in the treated U2OS cells. Cur-NPs upregulated the protein expression levels of cleaved caspase-3/caspase-9, cytochrome c, Apaf-1 and Bad and downregulated the protein expression level of p-Akt in U2OS cells. These results suggest Cur-NPs are effective in enhancing apoptosis in human osteosarcoma cells and thus could provide potential for cancer therapeutics.