Triptolide induces protective autophagy through activation of the CaMKKβ-AMPK signaling pathway in prostate cancer cells

Autophagy in benign prostatic hyperplasia: insights and therapeutic potential

Autophagy is a cellular homeostatic mechanism characterized by cyclic degradation. It plays an essential role in maintaining cellular quality and survival by eliminating dysfunctional cellular components. This process is pivotal in various pathophysiological processes. Benign prostatic hyperplasia (BPH) is a common urological disorder in middle-aged and elderly men. It frequently presents as lower urinary tract symptoms due to an increase in epithelial and stromal cells surrounding the prostatic urethra. The precise pathogenesis of BPH is complex. In recent years, research on autophagy in BPH has gained significant momentum, with accumulating evidence indicating its crucial role in the onset and progression of the disease. This review aims to outline the various roles of autophagy in BPH and elucidate potential therapeutic strategies targeting autophagy for managing BPH.

Phytochemicals regulate cancer metabolism through modulation of the AMPK/PGC-1α signaling pathway

BACKGROUND

Due to the complex pathophysiological mechanisms involved in cancer progression and metastasis, current therapeutic approaches lack efficacy and have significant adverse effects. Therefore, it is essential to establish novel strategies for combating cancer. Phytochemicals, which possess multiple biological activities, such as antioxidant, anti-inflammatory, antimutagenic, immunomodulatory, antiproliferative, anti-angiogenesis, and antimetastatic properties, can regulate cancer progression and interfere in various stages of cancer development by suppressing various signaling pathways.

METHODS

The current systematic and comprehensive review was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) criteria, using electronic databases, including PubMed, Scopus, and Science Direct, until the end of December 2023. After excluding unrelated articles, 111 related articles were included in this systematic review.

RESULTS

In this current review, the major signaling pathways of cancer metabolism are highlighted with the promising anticancer role of phytochemicals. This was through their ability to regulate the AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) signaling pathway. The AMPK/PGC-1α signaling pathway plays a crucial role in cancer cell metabolism via targeting energy homeostasis and mitochondria biogenesis, glucose oxidation, and fatty acid oxidation, thereby generating ATP for cell growth. As a result, targeting this signaling pathway may represent a novel approach to cancer treatment. Accordingly, alkaloids, phenolic compounds, terpene/terpenoids, and miscellaneous phytochemicals have been introduced as promising anticancer agents by regulating the AMPK/PGC-1α signaling pathway. Novel delivery systems of phytochemicals targeting the AMPK/PGC-1α pathway in combating cancer are also highlighted in this review.

Targeting epidermal growth factor receptor and its downstream signaling pathways by natural products: A mechanistic insight

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase (RTK) that maintains normal tissues and cell signaling pathways. EGFR is overactivated and overexpressed in many malignancies, including breast, lung, pancreatic, and kidney. Further, the EGFR gene mutations and protein overexpression activate downstream signaling pathways in cancerous cells, stimulating the growth, survival, resistance to apoptosis, and progression of tumors. Anti-EGFR therapy is the potential approach for treating malignancies and has demonstrated clinical success in treating specific cancers. The recent report suggests most of the clinically used EGFR tyrosine kinase inhibitors developed resistance to the cancer cells. This perspective provides a brief overview of EGFR and its implications in cancer. We have summarized natural products-derived anticancer compounds with the mechanistic basis of tumor inhibition via the EGFR pathway. We propose that developing natural lead molecules into new anticancer agents has a bright future after clinical investigation.

A comprehensive review on phytochemicals in the treatment and prevention of pancreatic cancer: Focusing on their mechanism of action

Background and Aims

Pancreatic cancer develops in the normal tissues of the pancreas from malignant cells. The chance of recovery is not good, and the chance of survival 5 years following diagnosis is quite low. Pancreatic cancer treatment strategies such as radiotherapy and chemotherapy had relatively low success rates. Therefore, the present study aims to explore new therapies for treating pancreatic cancer.

Methods

The present study searched for information about pancreatic cancer pathophysiology, available treatment options; and their comparative benefits and challenges. Aiming to identify potential alternative therapeutics, this comprehensive review analyzed information from renowned databases such as Scopus, PubMed, and Google Scholar.

Results

In recent years, there has been a rise in interest in the possibility that natural compounds could be used as treatments for cancer. Cannabinoids, curcumin, quercetin, resveratrol, and triptolide are some of the anticancer phytochemicals now used to manage pancreatic cancer. The above compounds are utilized by inhibiting or stimulating biological pathways such as apoptosis, autophagy, cell growth inhibition or reduction, oxidative stress, epithelial-mesenchymal transformation, and increased resistance to chemotherapeutic drugs in the management of pancreatic cancer.

Conclusion

Right now, surgery is the only therapeutic option for patients with pancreatic cancer. However, most people who get sick have been diagnosed too late to benefit from potentially effective surgery. Alternative medications, like natural compounds and herbal medicines, are promising complementary therapies for pancreatic cancer. Therefore, we recommend large-scale standardized clinical research for the investigation of natural compounds to ensure their consistency and comparability in pancreatic cancer treatment.

Antitumor mechanisms and future clinical applications of the natural product triptolide

Triptolide (TPL) is a compound sourced from Tripterygium wilfordii Hook. F., a traditional Chinese medicinal herb recognized for its impressive anti-inflammatory, anti-angiogenic, immunosuppressive, and antitumor qualities. Notwithstanding its favorable attributes, the precise mechanism through which TPL influences tumor cells remains enigmatic. Its toxicity and limited water solubility significantly impede the clinical application of TPL. We offer a comprehensive overview of recent research endeavors aimed at unraveling the antitumor mechanism of TPL in this review. Additionally, we briefly discuss current strategies to effectively manage the challenges associated with TPL in future clinical applications. By compiling this information, we aim to enhance the understanding of the underlying mechanisms involved in TPL and identify potential avenues for further advancement in antitumor therapy.

Drug repurposing for cancer therapy

Cancer, a complex and multifactorial disease, presents a significant challenge to global health. Despite significant advances in surgical, radiotherapeutic and immunological approaches, which have improved cancer treatment outcomes, drug therapy continues to serve as a key therapeutic strategy. However, the clinical efficacy of drug therapy is often constrained by drug resistance and severe toxic side effects, and thus there remains a critical need to develop novel cancer therapeutics. One promising strategy that has received widespread attention in recent years is drug repurposing: the identification of new applications for existing, clinically approved drugs. Drug repurposing possesses several inherent advantages in the context of cancer treatment since repurposed drugs are typically cost-effective, proven to be safe, and can significantly expedite the drug development process due to their already established safety profiles. In light of this, the present review offers a comprehensive overview of the various methods employed in drug repurposing, specifically focusing on the repurposing of drugs to treat cancer. We describe the antitumor properties of candidate drugs, and discuss in detail how they target both the hallmarks of cancer in tumor cells and the surrounding tumor microenvironment. In addition, we examine the innovative strategy of integrating drug repurposing with nanotechnology to enhance topical drug delivery. We also emphasize the critical role that repurposed drugs can play when used as part of a combination therapy regimen. To conclude, we outline the challenges associated with repurposing drugs and consider the future prospects of these repurposed drugs transitioning into clinical application.

Mechanisms of cancer cell death induction by triptolide: A comprehensive overview

The need for naturally occurring constituents is driven by the rise in the cancer prevalence and the unpleasant side effects associated with chemotherapeutics. Triptolide, the primary active component of "Tripterygium Wilfordii", has exploited for biological mechanisms and therapeutic potential against various tumors. Based on the recent pre-clinical investigations, triptolide is linked to the induction of death of cancerous cells by triggering cellular apoptosis via inhibiting heat shock protein expression (HSP70), and cyclin dependent kinase (CDKs) by up regulating expression of P21. MKP1, histone methyl transferases and RNA polymerases have all recently identified as potential targets of triptolide in cells. Autophagy, AKT signaling pathway and various pathways involving targeted proteins such as A-disintegrin & metalloprotease-10 (ADAM10), Polycystin-2 (PC-2), dCTP pyro-phosphatase 1 (DCTP1), peroxiredoxin-I (Prx-I), TAK1 binding protein (TAB1), kinase subunit (DNA-PKcs) and the xeroderma-pigmentosum B (XPB or ERCC3) have been exploited. Besides that, triptolide is responsible for enhancing the effectiveness of various chemotherapeutics. In addition, several triptolide moieties, including minnelide and LLDT8, have progressed in investigations on humans for the treatment of cancer. Targeted strategies, such as triptolide conjugation with ligands or triptolide loaded nano-carriers, are efficient techniques to confront toxicities associated with triptolide. We expect and anticipate that advances in near future, regarding combination therapies of triptolide, might be beneficial against cancerous cells.

Nucleo-cytoplasmic shuttling of 14-3-3 epsilon carrying hnRNP C promotes autophagy

Translocation of 14-3-3 protein epsilon (14-3-3ε) was found to be involved in Triptolide (Tp)-induced inhibition of colorectal cancer (CRC) cell proliferation. However, the form of cell death induced by 14-3-3ε translocation and mechanisms underlying this effect remain unclear. This study employed label-free LC-MS/MS to identify 14-3-3ε-associated proteins in CRC cells treated with or without Tp. Our results confirmed that heterogeneous nuclear ribonucleoproteins C1/C2 (hnRNP C) were exported out of the nucleus by 14-3-3ε and degraded by ubiquitination. The nucleo-cytoplasmic shuttling of 14-3-3ε carrying hnRNP C mediated Tp-induced proliferation inhibition, cell cycle arrest and autophagic processes. These findings have broad implications for our understanding of 14-3-3ε function, provide an explanation for the mechanism of nucleo-cytoplasmic shuttling of hnRNP C and provide new insights into the complex regulation of autophagy.

Possible therapeutic role of zinc oxide nanoparticles versus vanillic acid in testosterone-induced benign prostatic hyperplasia in adult albino rat: A histological, immunohistochemical and biochemical study

BACKGROUND

The search for alternative therapies for treatment of Benign prostatic hyperplasia (BPH) has been increasingly studied to avoid the common adverse effects of the usual regimens. Therefore, this study aimed at delineating possible mechanisms of benign prostatic hyperplasia (BPH) and possible therapeutic role of zinc oxide nanoparticles (ZnO-NPs) versus vanillic acid.

METHODS

Forty rats were divided into five groups: control, sham control, Testosterone-induced BPH, BPH and Zn-NPs, and BPH and vanillic acid. Light microscopic, immune-histochemical; PCNA, Bcl-2, Bax, caspase-3, p-Akt and p-mTOR, histomorphometric analysis, MDA/SOD and GPx and were done. Gene expression of p-Akt, p-mTOR and survivin were evaluated.

RESULTS

Application of zinc oxide nanoparticles as well as vanillic acid significantly reduced prostatic index, epithelial thickness, stromal collagen fibers, expression of PCNA, Bcl2, p-Akt, p-mTOR and MDA tissue level (p < 0.05). Whereas expression of Bax and caspase 3, and tissue levels of SOD and GPx were significantly increased in groups treated with Zno-Nps and vanillic acid compared to that of BPH group. Zinc oxide nanoparticles showed a better effect than vanillic acid in alleviating BPH.

CONCLUSION

These findings suggested that ZnO-NPs as well as VA ameliorated the histolo-pathological and biochemical effects of induced BPH, moreover they improved the proapoptotic and antioxidant parameters which ere induced in BPH. It is recommended to search for new agents to prevent the development and progression of BPH.

Mechanisms of cancer cell death induction by triptolide

Drug resistance is a hot topic issue in cancer research and therapy. Although cancer therapy including radiotherapy and anti-cancer drugs can kill malignant cells within the tumor, cancer cells can develop a wide range of mechanisms to resist the toxic effects of anti-cancer agents. Cancer cells may provide some mechanisms to resist oxidative stress and escape from apoptosis and attack by the immune system. Furthermore, cancer cells may resist senescence, pyroptosis, ferroptosis, necroptosis, and autophagic cell death by modulating several critical genes. The development of these mechanisms leads to resistance to anti-cancer drugs and also radiotherapy. Resistance to therapy can increase mortality and reduce survival following cancer therapy. Thus, overcoming mechanisms of resistance to cell death in malignant cells can facilitate tumor elimination and increase the efficiency of anti-cancer therapy. Natural-derived molecules are intriguing agents that may be suggested to be used as an adjuvant in combination with other anticancer drugs or radiotherapy to sensitize cancer cells to therapy with at least side effects. This paper aims to review the potential of triptolide for inducing various types of cell death in cancer cells. We review the induction or resistance to different cell death mechanisms such as apoptosis, autophagic cell death, senescence, pyroptosis, ferroptosis, and necrosis following the administration of triptolide. We also review the safety and future perspectives for triptolide and its derivatives in experimental and human studies. The anticancer potential of triptolide and its derivatives may make them effective adjuvants for enhancing tumor suppression in combination with anticancer therapy.

Advances in autophagy modulation of natural products in cervical cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Natural products play a critical role in drug development and is emerging as a potential source of biologically active metabolites for therapeutic intervention, especially in cancer therapy. In recent years, there is increasing evidence that many natural products may modulate autophagy through various signaling pathways in cervical cancer. Understanding the mechanisms of these natural products helps to develop medications for cervical cancer treatments.

AIM OF THE STUDY

In recent years, there is increasing evidence that many natural products may modulate autophagy through various signaling pathways in cervical cancer. In this review, we briefly introduce autophagy and systematically describe several classes of natural products implicated in autophagy modulation in cervical cancer, hoping to provide valuable information for the development of cervical cancer treatments based on autophagy.

MATERIALS AND METHODS

We searched for studies on natural products and autophagy in cervical cancer on the online database and summarized the relationship between natural products and autophagy modulation in cervical cancer.

RESULTS

Autophagy is a lysosome-mediated catabolic process in eukaryotic cells that plays an important role in a variety of physiological and pathological processes, including cervical cancer. Abnormal expression of cellular autophagy and autophagy-related proteins has been implicated in cervical carcinogenesis, and human papillomavirus infection can affect autophagic activity. Flavonoids, alkaloids, polyphenols, terpenoids, quinones, and other compounds are important sources of natural products that act as anticancer agents. In cervical cancer, natural products exert the anticancer function mainly through the induction of protective autophagy.

CONCLUSIONS

The regulation of cervical cancer autophagy by natural products has significant advantages in inducing apoptosis, inhibiting proliferation, and reducing drug resistance in cervical cancer.

The endoplasmic reticulum stress response in prostate cancer

In order to proliferate in unfavourable conditions, cancer cells can take advantage of the naturally occurring endoplasmic reticulum-associated unfolded protein response (UPR) via three highly conserved signalling arms: IRE1α, PERK and ATF6. All three arms of the UPR have key roles in every step of tumour progression: from cancer initiation to tumour growth, invasion, metastasis and resistance to therapy. At present, no cure for metastatic prostate cancer exists, as targeting the androgen receptor eventually results in treatment resistance. New research has uncovered an important role for the UPR in prostate cancer tumorigenesis and crosstalk between the UPR and androgen receptor signalling pathways. With an improved understanding of the mechanisms by which cancer cells exploit the endoplasmic reticulum stress response, targetable points of vulnerability can be uncovered.

AMPK's double-faced role in advanced stages of prostate cancer

Prostate cancer (PCa) is the second leading cause of cancer deaths in men. Unfortunately, a very limited number of drugs are available for the relapsed and advanced stages of PCa, adding only a few months to survival; therefore, it is vital to develop new drugs. 5´ AMP-activated protein kinase (AMPK) is a master regulator of cell metabolism. It plays a significant role in the metabolism of PCa; hence, it can serve well as a treatment option for the advanced stages of PCa. However, whether this pathway contributes to cancer cell survival or death remains unknown. The present study reviews the possible pathways by which AMPK plays role in the advanced stages of PCa, drug resistance, and metastasis: (1) AMPK has a contradictory role in promoting glycolysis and the Warburg effect which are correlated with cancer stem cells (CSCs) survival and advanced PCa. It exerts its effect by interacting with hypoxia-induced factor 1 (HIF1) α, pyruvate kinase 2 (PKM2), glucose transporter (GLUT) 1 and pyruvate dehydrogenase complex (PDHC), which are key regulators of glycolysis; however, whether it promotes or discourage glycolysis is not conclusive. It can also exert an anti-CSC effect by negative regulation of NANOG and epithelial-mesenchymal transition (EMT) transcription factors, which are the major drivers of CSC maintenance; (2) the regulatory effect of AMPK on autophagy is also noticeable. Androgen receptors' expression increases AMPK activation through Calcium/calmodulin-dependent protein kinase 2 (CaMKK2) and induces autophagy. In addition, AMPK itself increases autophagy by downregulating the mammalian target of rapamycin complex (mTORC). However, whether increased autophagy inhibits or promotes cell death and drug resistance is contradictory. This study reveals that there are numerous pathways other than cell metabolism by which AMPK exerts its effects in the advanced stages of PCa, making it a priceless treatment target. Finally, we mention some drugs developed to treat the advanced stages of PCa by acting on AMPK.

Peroxisome Proliferator Activated Receptor Gamma Coactivator-1 Alpha: A Double-Edged Sword in Prostate Cancer

Peroxisome proliferator activated receptor gamma coactivator-1 alpha (PGC-1α/PPARGC1A) is a pivotal transcriptional coactivator involved in the regulation of mitochondrial metabolism, including biogenesis and oxidative metabolism. PGC-1α is finely regulated by AMP-activated protein kinases (AMPKs), the role of which in tumors remains controversial to date. In recent years, a growing amount of research on PGC-1α and tumor metabolism has emphasized its importance in a variety of tumors, including prostate cancer (PCA). Compelling evidence has shown that PGC-1α may play dual roles in promoting and inhibiting tumor development under certain conditions. Therefore, a better understanding of the critical role of PGC-1α in PCA pathogenesis will provide new insights into targeting PGC-1α for the treatment of this disease. In this review, we highlight the procancer and anticancer effects of PGC-1α in PCA and aim to provide a theoretical basis for targeting AMPK/PGC-1α to inhibit the development of PCA. In addition, our recent findings provide a candidate drug target and theoretical basis for targeting PGC-1α to regulate lipid metabolism in PCA.

Dihydromyricetin Ameliorates Inflammation-Induced Insulin Resistance via Phospholipase C-CaMKK-AMPK Signal Pathway

Patients with metabolic syndrome have a higher risk of type II diabetes and cardiovascular disease. The metabolic syndrome has become an urgent public health problem. Insulin resistance is the common pathophysiological basis of metabolic syndrome. The higher incidence of insulin resistance in obese groups is due to increased levels of inflammatory factors during obesity. Therefore, developing a therapeutic strategy for insulin resistance has great significance for the treatment of the metabolic syndrome. Dihydromyricetin, as a bioactive polyphenol, has been used for anti-inflammatory, antitumor, and improving insulin sensitivity. However, the target of DHM and molecular mechanism of DHM for preventing inflammation-induced insulin resistance is still unclear. In this study, we first confirmed the role of dihydromyricetin in inflammation-induced insulin resistance in vivo and in vitro. Then, we demonstrated that dihydromyricetin resisted inflammation-induced insulin resistance by activating Ca2+-CaMKK-AMPK using signal pathway blockers, Ca2+ probes, and immunofluorescence. Finally, we clarified that dihydromyricetin activated Ca2+-CaMKK-AMPK signaling pathway by interacting with the phospholipase C (PLC), its target protein, using drug affinity responsive target stability (DARTS) assay. Our results not only demonstrated that dihydromyricetin resisted inflammation-induced insulin resistance via the PLC-CaMKK-AMPK signal pathway but also discovered that the target protein of dihydromyricetin is the PLC. Our results provided experimental data for the development of dihydromyricetin as a functional food and new therapeutic strategies for treating or preventing PLC.

Molecular Basis of Prostate Cancer and Natural Products as Potential Chemotherapeutic and Chemopreventive Agents

Prostate cancer is the second most common malignant cancer in males. It involves a complex process driven by diverse molecular pathways that closely related to the survival, apoptosis, metabolic and metastatic characteristics of aggressive cancer. Prostate cancer can be categorized into androgen dependent prostate cancer and castration-resistant prostate cancer and cure remains elusive due to the developed resistance of the disease. Natural compounds represent an extraordinary resource of structural scaffolds with high diversity that can offer promising chemical agents for making prostate cancer less devastating and curable. Herein, those natural compounds of different origins and structures with potential cytotoxicity and/or in vivo anti-tumor activities against prostate cancer are critically reviewed and summarized according to the cellular signaling pathways they interfere. Moreover, the anti-prostate cancer efficacy of many nutrients, medicinal plant extracts and Chinese medical formulations were presented, and the future prospects for the application of these compounds and extracts were discussed. Although the failure of conventional chemotherapy as well as involved serious side effects makes natural products ideal candidates for the treatment of prostate cancer, more investigations of preclinical and even clinical studies are necessary to make use of these medical substances reasonably. Therefore, the elucidation of structure-activity relationship and precise mechanism of action, identification of novel potential molecular targets, and optimization of drug combination are essential in natural medicine research and development.

Therapeutic potentials of resveratrol in combination with radiotherapy and chemotherapy during glioblastoma treatment: a mechanistic review

Glioblastoma, WHO grade IV astrocytoma, is the most aggressive type of brain tumors. These cancerous cells have a rapid growth rate, tendency to penetrate vital brain structures, molecular heterogeneity, etc. and this cancer is associated with a poor prognosis and low survival rate. Due to the resistance of glioblastoma cells to conventional therapeutic modalities (such as radiation therapy and chemotherapy) as well as the adverse effects of these modalities, the researchers have attempted to discover an appropriate alternative or adjuvant treatment for glioblastoma. Resveratrol, as an herbal and natural polyphenolic compound, has anti-tumoral property and has shown to be effective in GBM treatment. Resveratrol exerts its anti-tumoral effect through various mechanisms such as regulation of cell cycle progression and cell proliferation, autophagy, oxidant system, apoptosis pathways, and so on. Resveratrol in combination with radiation therapy and chemotherapy has also been used. In the present study, we summarized the current findings on therapeutic potentials of resveratrol in glioblastoma radiotherapy and chemotherapy.

Terpenoids' anti-cancer effects: focus on autophagy

Terpenoids are the largest class of natural products, most of which are derived from plants. Amongst their numerous biological properties, their anti-tumor effects are of interest for they are extremely diverse which include anti-proliferative, apoptotic, anti-angiogenic, and anti-metastatic activities. Recently, several in vitro and in vivo studies have been dedicated to understanding the 'terpenoid induced autophagy' phenomenon in cancer cells. Light has already been shed on the intricacy of apoptosis and autophagy relationship. This latter crosstalk is driven by the delicate balance between activating or silencing of certain proteins whereby the outcome is expressed via interrelated signaling pathways. In this review, we focus on nine of the most studied terpenoids and on their cell death and autophagic activity. These terpenoids are grouped in three classes: sesquiterpenoid (artemisinin, parthenolide), diterpenoids (oridonin, triptolide), and triterpenoids (alisol, betulinic acid, oleanolic acid, platycodin D, and ursolic acid). We have selected these nine terpenoids among others as they belong to the different major classes of terpenoids and our extensive search of the literature indicated that they were the most studied in terms of autophagy in cancer. These terpenoids alone demonstrate the complexity by which these secondary metabolites induce autophagy via complex signaling pathways such as MAPK/ERK/JNK, PI3K/AKT/mTOR, AMPK, NF-kB, and reactive oxygen species. Moreover, induction of autophagy can be either destructive or protective in tumor cells. Nevertheless, should this phenomenon be well understood, we ought to be able to exploit it to create novel therapies and design more effective regimens in the management and treatment of cancer.

Zinc oxide nanoparticles reduce the chemoresistance of gastric cancer by inhibiting autophagy

BACKGROUND

Gastric cancer (GC) is a common malignancy that results in a high rate of cancer-related mortality. Cisplatin (DDP)-based chemotherapy is the first-line clinical treatment for GC therapy, but chemotherapy resistance remains a severe clinical challenge. Zinc oxide nanoparticle (ZnO-NP) has been identified as a promising anti-cancer agent, but the function of ZnO-NP in GC development is still unclear.

AIM

To explore the effect of ZnO-NP on chemotherapy resistance during GC progression.

METHODS

ZnO-NP was synthesized, and the effect and underlying mechanisms of ZnO-NP on the malignant progression and chemotherapy resistance of GC cells were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, colony formation assays, transwell assays, wound healing assays, flow cytometry, and Western blot analysis in GC cells and DDP-resistant GC cells, and by tumorigenicity analyses in nude mice.

RESULTS

Our data revealed that ZnO-NP was able to inhibit proliferation, migration, and invasion and induce apoptosis of GC cells. Meanwhile, ZnO-NP significantly reduced the half maximal inhibitory concentration (IC50) of DDP for the inhibition of cell proliferation of DDP-resistant SGC7901/DDP cell lines. Autophagy was increased in DDP-resistant GC cells, as demonstrated by elevated light chain 3-like protein 2 (LC3II)/LC3I and Beclin-1 expression and repressed p62 expression in SGC7901/DDP cells compared to SGC7901 cells. Mechanically, ZnO-NP inhibited autophagy in GC cells and treatment with DDP induced autophagy, which was reversed by ZnO-NP. Functionally, ZnO-NP attenuated the tumor growth of DDP-resistant GC cells in vivo.

CONCLUSION

We conclude that ZnO-NP alleviates the chemoresistance of GC cells by inhibiting autophagy. Our findings present novel insights into the mechanism by which ZnO-NP regulates the chemotherapy resistance of GC. ZnO-NP may serve as a potential therapeutic candidate for GC treatment. The potential role of ZnO-NP in the clinical treatment of GC needs clarification in future investigations.

Tripterygium glycoside suppresses epithelial‑to‑mesenchymal transition of diabetic kidney disease podocytes by targeting autophagy through the mTOR/Twist1 pathway

Tripterygium glycoside (TG) is a traditional Chinese medicine extract with immunosuppressive, anti-inflammatory and anti-renal fibrosis effects. Epithelial-mesenchymal transition (EMT) and cell apoptosis are considered to be the major cause of podocyte injury in diabetic kidney disease (DKD). However, it remains unknown as to whether TG is able to alleviate podocyte injury to prevent DKD progression. Therefore, the present study aimed to clarify the podocyte protective effects of TG on DKD. TG, Twist1 small interfering RNA (siRNA) and Twist1 overexpression vector were added to DKD mouse serum-induced podocytes in vitro. Autophagic and EMT activities were evaluated by immunofluorescence staining and western blot analysis. Apoptotic activity was evaluated by Annexin V-FITC/PI flow cytometric analysis. The results revealed that after treatment with DKD mouse serum, autophagy was decreased, whereas EMT and apoptotic rate were increased, in podocytes. In addition, Twist1 expression was increased in DKD-induced podocytes. Furthermore, following Twist1-small interfering RNA transfection, the DKD-induced podocyte EMT and apoptotic rate were markedly reduced, indicating that Twist1 may be a promising therapeutic target for DKD. The present results also revealed that overexpression of Twist1 increased podocyte apoptosis, although this was decreased after TG treatment, indicating that TG may exhibit a protective effect on podocytes by inhibiting the Twist1 signaling pathway. After the addition of 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one, an activator of mTORC1, the effects of TG on podocyte EMT, apoptosis and the autophagy were reversed. These findings indicated that TG may alleviate EMT and apoptosis by upregulating autophagy through the mTOR/Twist1 signaling pathway in DKD.

Potential therapeutic compounds from traditional Chinese medicine targeting endoplasmic reticulum stress to alleviate rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease which affects about 0.5-1% of people with symptoms that significantly impact a sufferer's lifestyle. The cells involved in propagating RA tend to display pro-inflammatory and cancer-like characteristics. Medical drug treatment is currently the main avenue of RA therapy. However, drug options are limited due to severe side effects, high costs, insufficient disease retardation in a majority of patients, and therapeutic effects possibly subsiding over time. Thus there is a need for new drug therapies. Endoplasmic reticulum (ER) stress, a condition due to accumulation of misfolded proteins in the ER, and subsequent cellular responses have been found to be involved in cancer and inflammatory pathologies, including RA. ER stress protein markers and their modulation have therefore been suggested as therapeutic targets, such as GRP78 and CHOP, among others. Some current RA therapeutic drugs have been found to have ER stress-modulating properties. Traditional Chinese Medicines (TCMs) frequently use natural products that affect multiple body and cellular targets, and several medicines and/or their isolated compounds have been found to also have ER stress-modulating capabilities, including TCMs used in RA treatment by Chinese Medicine practitioners. This review encourages, in light of the available information, the study of these RA-treating, ER stress-modulating TCMs as potential new pharmaceutical drugs for use in clinical RA therapy, along with providing a list of other ER stress-modulating TCMs utilized in treatment of cancers, inflammatory diseases and other diseases, that have potential use in RA treatment given similar ER stress-modulating capacity.

The Local Anesthetic Bupivacaine Inhibits the Progression of Non-Small Cell Lung Cancer by Inducing Autophagy Through Akt/mTOR Signaling

Non-small cell lung cancer (NSCLC) is a prevalent malignancy with high mortality and poor prognosis. Bupivacaine serves as a widely used local anesthetic and presents potential anti-tumor activity. Nevertheless, the function of bupivacaine in the NSCLC development remains elusive. Here, we tried to investigate the impact of bupivacaine on the NSCLC progression. Significantly, we revealed that bupivacaine was able to reduce the proliferation and induce the apoptosis of NSCLC cells. Bupivacaine could attenuate the invasion and migration in the cells. Mechanically, the treatment of bupivacaine increased the expression ratio of light chain 3B-II (LC3B-II)/LC3B-I and the expression of Beclin-1 in the NSCLC cells. Meanwhile, the expression of the autophagic adaptor protein p62 was decreased by bupivacaine treatment in the cells. The treatment of bupivacaine attenuated the phosphorylation of AKT and mTOR in the NSCLC cells. The AKT activator SC79 and autophagy inhibitor 3-methyladenine (3-MA) reversed the bupivacaine-inhibited phosphorylation of AKT and mTOR and bupivacaine-induced autophagy, as well as the bupivacaine-attenuated NSCLC progression in the cells. Bupivacaine could inhibit the tumor growth in vivo. In conclusion, we discovered that the local anesthetic bupivacaine inhibited the progression of NSCLC by inducing autophagy through Akt/mTOR signaling. Our finding provides new insights into the mechanism by which bupivacaine attenuates the development of NSCLC. Bupivacaine may serve as a potential anti-tumor candidate for the therapeutic strategy of NSCLC.

Inhibition of CAMKK2 impairs autophagy and castration-resistant prostate cancer via suppression of AMPK-ULK1 signaling

Previous work has suggested androgen receptor (AR) signaling mediates prostate cancer progression in part through the modulation of autophagy. However, clinical trials testing autophagy inhibition using chloroquine derivatives in men with castration-resistant prostate cancer (CRPC) have yet to yield promising results, potentially due to the side effects of this class of compounds. We hypothesized that identification of the upstream activators of autophagy in prostate cancer could highlight alternative, context-dependent targets for blocking this important cellular process during disease progression. Here, we used molecular, genetic, and pharmacological approaches to elucidate an AR-mediated autophagy cascade involving Ca2+/calmodulin-dependent protein kinase kinase 2 (CAMKK2; a kinase with a restricted expression profile), 5'-AMP-activated protein kinase (AMPK), and Unc-51 like autophagy activating kinase 1 (ULK1), but independent of canonical mechanistic target of rapamycin (mTOR) activity. Increased CAMKK2-AMPK-ULK1 signaling correlated with disease progression in genetic mouse models and patient tumor samples. Importantly, CAMKK2 disruption impaired tumor growth and prolonged survival in multiple CRPC preclinical mouse models. Similarly, an inhibitor of AMPK-ULK1 blocked autophagy, cell growth, and colony formation in prostate cancer cells. Collectively, our findings converge to demonstrate that AR can co-opt the CAMKK2-AMPK-ULK1 signaling cascade to promote prostate cancer by increasing autophagy. Thus, this pathway may represent an alternative autophagic target in CRPC.

Perspectives of Molecular Therapy-Targeted Mitochondrial Fission in Hepatocellular Carcinoma

Current advances of molecular-targeting therapies for hepatocellular carcinoma (HCC) have improved the overall survival significantly, whereas the results still remain unsatisfied. Recently, much attention has been focused on organelles, such as the mitochondria, to reveal novel strategies to control the cancers. The mitochondria are vital organelles which supply energy and maintain metabolism in most of the eukaryotic cells. They not only execute critical bioenergetic and biosynthetic functions but also regulate ROS homeostasis and apoptosis. Existing in a dynamic equilibrium state, mitochondria constantly undergo the fission and fusion processes in normal situation. Increasing evidences have showed that mitochondrial fission is highly related to the diseases and cancers. Distinctive works have proved the significant effects of mitochondrial fission on HCC behaviors and the crosstalks with other molecular pathways. Here, we provide an overview of the mitochondrial fission and the link with HCC, emphasizing on the underlying molecular pathways and several novel materials that modulate HCC behaviors.

A review of the processed Polygonum multiflorum (Thunb.) for hepatoprotection: Clinical use, pharmacology and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonum multiflorum (Thunb.) (PMT) is a member of Polygonaceae. Traditional Chinese medicine considers that the processed PMT can tonify liver, nourish blood and blacken hair. In recent years, the processed PMT and its active ingredients have significant therapeutic effects on nonalcoholic fatty liver disease, alcoholic fatty liver disease, viral hepatitis, liver fibrosis and liver cancer.

AIM OF THE STUDY

The main purpose of this review is to provide a critical appraisal of the existing knowledge on the clinical application, hepatoprotective pharmacology and hepatotoxicity, it provides a comprehensive evaluation of the liver function of the processed PMT.

MATERIALS AND METHODS

A detailed literature search was conducted using various online search engines, such as Pubmed, Google Scholar, Mendeley, Web of Science and China National Knowledge Infrastructure (CNKI) database. The main active components of the processed PMT and the important factors in the occurrence and development of liver diseases are used as key words to carry out detailed literature retrieval.

RESULTS

In animal and cell models, the processed PMT and active components can treat various liver diseases, such as fatty liver induced by high-fat diet, liver injury and fibrosis induced by drugs, viral transfected hepatitis, hepatocellular carcinoma, etc. They can protect liver by regulating lipid metabolism related enzymes, resisting insulin resistance, decreasing the expression of inflammatory cytokines, inhibiting the activation of hepatic stellate cells, reducing generation of extracellular matrix, promoting cancer cell apoptosis and controlling the growth of tumor cells, etc. However, improperly using of the processed PMT can cause liver injury, which is associated with the standardization of processing, the constitution of the patients, the characteristics of the disease, and the administration of dosage and time.

CONCLUSION

The processed PMT can treat various liver diseases via reasonably using, and the active compounds (2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside, emodin, physcion, etc.) are promising candidate drugs for developing new liver protective agents. However, some components have a "toxic-effective" bidirectional effect, which should be used cautiously.

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.

Effects of dietary zinc level on growth performance, lipolysis and expression of genes involved in the calcium/calmodulin-dependent protein kinase kinase-β/AMP-activated protein kinase pathway in juvenile Pacific white shrimp

The present study evaluated the effects of dietary Zn level on growth performance, serum and hepatopancreas metabolites, expression of genes involved in lipid and energy metabolism, and the signalling pathway of dietary Zn-induced lipolysis. Five isonitrogenous and isolipidic diets were formulated to contain different Zn levels: 46·4 (basal diet), 77·2, 87·0, 117·1 and 136·8 mg/kg, respectively. The results indicated that shrimp fed the diet containing Zn at 117·1 mg/kg had higher weight gain and specific growth rate, and the lowest feed intake and feed conversion rate, than shrimp fed the other diets. The deposition rate of Zn in whole body significantly decreased with increasing dietary Zn level. Dietary Zn prevented the accumulation of free radicals and improved antioxidant activities by increasing Cu/Zn superoxide dismutase and reducing malondialdehyde in hepatopancreas. Dietary Zn supplementation enhanced lipase activity and adiponectin, which could promote TAG breakdown and fatty acid oxidation and lead to reduced lipid in hepatopancreas. The mRNA expressions ofob-rb,adipor,camkkβ,ampk,cd36,mcdandcpt1involved in Zn-induced lipid catabolism were up-regulated, and the expressions ofsrebp,acc,fasandscd1were down-regulated. The mRNA levels of SLC39 family genes (zip3,zip9,zip11andzip14) in hepatopancreas were up-regulated with increasing dietary Zn level. The results demonstrated that dietary Zn level could significantly affect growth performance, tissue deposition of Zn, lipid metabolites and expression of genes involved in lipogenesis and lipolysis inLitopenaeus vannamei.

Triptolide induces atrophy of myotubes by triggering IRS-1 degradation and activating the FoxO3 pathway

Triptolide is an active ingredient isolated from an ancient Chinese herb (Tripterygium wilfordii Hook. f) for inflammatory and immune disorders. It has been shown to inhibit the proliferation of skeletal muscle; however, mechanisms of this effect remain unclear. We used mouse C2C12 myotubes as an in vitro model to investigate the effects of triptolide on skeletal muscle. Triptolide markedly inhibited the expression of myosin heavy chain and upregulated the expression of muscle atrophy-related proteins, leading to atrophy of the myotubes. Triptolide dose-dependently decreased the phosphorylation of Forkhead box O3 (FoxO3) and activated FoxO3 transcription activity, which regulates the expression of muscle atrophy-related proteins. Furthermore, triptolide inhibited the phosphorylation of Akt on the site of S473 and T308, and decreased the phosphorylation of insulin receptor substrate-1 (IRS-1) on the site of S302. In addition, triptolide reduced the protein level, but not mRNA level of IRS-1, whereas other upstream regulators of the Akt signaling pathway were not affected. Finally, a time-course experiment showed that the triptolide-induced degradation of IRS-1 in myotubes occurred 12 h prior to both inhibition of Akt activity and the activation of FoxO3. These data indicate that triptolide triggers IRS-1 degradation to promote FoxO3 activation, which subsequently led to atrophy of myotubes, providing us a potential target to prevent triptolide-induced skeletal muscle atrophy.

Naturally occurring anti-cancer compounds: shining from Chinese herbal medicine

Numerous natural products originated from Chinese herbal medicine exhibit anti-cancer activities, including anti-proliferative, pro-apoptotic, anti-metastatic, anti-angiogenic effects, as well as regulate autophagy, reverse multidrug resistance, balance immunity, and enhance chemotherapy in vitro and in vivo. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2011) on the key compounds with anti-cancer effects derived from Chinese herbal medicine (curcumin, epigallocatechin gallate, berberine, artemisinin, ginsenoside Rg3, ursolic acid, silibinin, emodin, triptolide, cucurbitacin B, tanshinone I, oridonin, shikonin, gambogic acid, artesunate, wogonin, β-elemene, and cepharanthine) in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we focused on their recently discovered and/or investigated pharmacological effects, novel mechanism of action, relevant clinical studies, and their innovative applications in combined therapy and immunomodulation. In addition, the present review has extended to describe other promising compounds including dihydroartemisinin, ginsenoside Rh2, compound K, cucurbitacins D, E, I, tanshinone IIA and cryptotanshinone in view of their potentials in cancer therapy. Up to now, the evidence about the immunomodulatory effects and clinical trials of natural anti-cancer compounds from Chinese herbal medicine is very limited, and further research is needed to monitor their immunoregulatory effects and explore their mechanisms of action as modulators of immune checkpoints.

1H NMR-Based Metabolomics Reveals the Antitumor Mechanisms of Triptolide in BALB/c Mice Bearing CT26 Tumors

Triptolide, the main active ingredient in Tripterygium wilfordii Hook. f. (Celastraceae), has shown promising effects against a variety of tumors. However, the molecular pharmacological mechanisms explaining the action of triptolide remain unknown. In this study, the CT26 colon tumor cell line was inoculated subcutaneously into BALB/c mice, and plasma samples were subjected to ¹H NMR metabolomics analysis. The metabolic signature identified five metabolites whose levels were lower and 15 whose levels were higher in CT26 tumor-bearing mice than in normal control mice. Triptolide treatment significantly reversed the levels of nine of these metabolites, including isoleucine, glutamine, methionine, proline, 3-hydroxybutyric acid, 2-hydroxyisovalerate, 2-hydroxyisobutyrate, and low-density lipoprotein/very low-density lipoprotein. Based on the identities of these potential biomarkers, we conclude that the antitumor mechanism of triptolide might rely on correcting perturbations in branched-chain amino acid metabolism, serine/glycine/methionine biosynthesis, and ketone bodies metabolism.

Autophagy in Triptolide-Mediated Cytotoxicity in Hepatic Cells

Triptolide is a major active ingredient isolated from the traditional Chinese herb Tripterygium wilfordii Hook F. However, its use in clinical practice is limited due to its severe hepatotoxicity. Autophagy, a highly conserved intracellular process, is essential for maintaining cytoplasmic homeostasis. Considering that abnormalities in autophagy are closely associated with drug-mediated hepatotoxicity, we applied human normal liver HL7702 cells to elucidate the roles of autophagy in triptolide-induced hepatotoxicity. Our study revealed that triptolide was cytotoxic to HL7702 cells. It markedly increased autophagosome formation and expression of autophagy-related proteins, namely Beclin1 and microtubule-associated protein 1 light chain 3II, and induced oxidative stress. These proautophagic effects were counteracted by pretreatment with N-acetylcysteine, a reactive oxygen species scavenger. Moreover, the pharmacological suppression of autophagy further exacerbated triptolide-elicited decrease in cell viability, increase in lactate dehydrogenase leakage, and activation of apoptosis proteases (caspase 3 and caspase 9). Our findings suggest that triptolide-induced oxidative stress consequently enhances autophagic activity, and autophagy is a cytoprotective mechanism against triptolide-induced cytotoxicity in HL7702 cells.

The Hard-To-Close Window of T-Type Calcium Channels

T-Type calcium channels (TTCCs) are key regulators of membrane excitability, which is the reason why TTCC pharmacology is subject to intensive research in the neurological and cardiovascular fields. TTCCs also play a role in cancer physiology, and pharmacological blockers such as tetralols and dihydroquinazolines (DHQs) reduce the viability of cancer cells in vitro and slow tumor growth in murine xenografts. However, the available compounds are better suited to blocking TTCCs in excitable membranes rather than TTCCs contributing window currents at steady potentials. Consistently, tetralols and dihydroquinazolines exhibit cytostatic/cytotoxic activities at higher concentrations than those required for TTCC blockade, which may involve off-target effects. Gene silencing experiments highlight the targetability of TTCCs, but further pharmacological research is required for TTCC blockade to become a chemotherapeutic option.

HIV "shock and kill" therapy: In need of revision

The implementation of antiretroviral therapy 23 years ago has rendered HIV infection clinically manageable. However, the disease remains incurable, since it establishes latent proviral reservoirs, which in turn can stochastically begin reproducing viral particles throughout the patient's lifetime. Viral latency itself depends in large part on the silencing environment of the infected host cell, which can be chemically manipulated. "Shock and kill" therapy intends to reverse proviral quiescence by inducing transcription with pharmaceuticals and allowing a combination of antiretroviral therapy, host immune clearance and HIV-cytolysis to remove latently infected cells, leading to a complete cure. Over 160 compounds functioning as latency-reversing agents (LRAs) have been identified to date, but none of the candidates has yet led to a promising functional cure. Furthermore, fundamental bioinformatic and clinical research from the past decade has highlighted the complexity and highly heterogeneous nature of the proviral reservoirs, shedding doubt on the "shock and kill" concept. Alternative therapies such as the HIV transcription-inhibiting "block and lock" strategy are therefore being considered. In this review we describe the variety of existing classes of LRAs, discuss their current drawbacks and highlight the potential for combinatorial "shocktail" therapies for potent proviral reactivation. We also suggest investigating LRAs with lesser-known mechanisms of action, and examine the feasibility of "block and lock" therapy.

Wilforine, the Q-marker and PK-maker of Tripterygium glycosides tablet: Based on preparation quantitative analysis and PK-PD study

BACKGROUND

The quality standard of Tripterygium glycosides tablet (TGT) by CFDA can not fully reflect the effectiveness and safety. While, Q-marker was proposed to solve the problem of traditional Chinese medicine. PK-marker is mainly used to reflect the material exposure and the influencing factors of Chinese medicine after administration.

PURPOSE

Based on the study of quantitative analysis, cytotoxicity and pharmacokinetics, this study screened out and confirmed whether wilforine could be served as a potential Q-marker and PK-marker of TGT.

METHODS

A sensitive and selective UPLC-MS/MS method was developed and applied to quantitative research of TGT preparation and pharmacokinetics study of TGT. Then, HepG2 cells assay was used to evaluate the cytotoxicity induced by alkaloids in TGT. Then, a PK-PD research was carried out in adjuvant arthritis (AA) rats and control rats after oral administration of TGT, with different dosage and timing. The pharmacokinetic characteristics were determined and calculated by DAS1.0. The pharmacodynamics of TGT was evaluated by the change of paw swelling through one-way ANOVA analysis.

RESULTS

The quality of four alkaloids showed significant difference among four manufacturers, and they were abundant component in TGT from three manufacturers of all. HepG2 cells test revealed that wilforine and wilforgine could induce the cytotoxicity obviously. Pharmacodynamics index suggested that TGT had therapeutic effect on adjuvant arthritis. Thus, the four cases of death occurred in the high dose AA rat group had proven the significant toxicity caused by continuous high dose TGT administration. Furthermore, the result of pharmacokinetic study proved that C_max, and AUC_(0-tn) of wilforine have dose-dependent and time-dependent characteristics. But for wilforgine, there was no indication that there was an accumulation phenomenon in vivo and its plasma concentration showed low exposure. Therefore, it could hardly become the PK-marker of TGT.

CONCLUSION

Wilforine is proposed as a biologically active and toxic component of TGT that can be served both as Q-marker and PK-marker. The quality, clinical safety, and efficacy of TGT should be evaluated by the quality of wilforine.

Resveratrol, an activator of SIRT1, induces protective autophagy in non-small-cell lung cancer via inhibiting Akt/mTOR and activating p38-MAPK

Background

Resveratrol, a natural polyphenolic phytoalexin, has potent anti-tumor activity. Recently, it was found to induce autophagy in cancer cells. However, the effects of resveratrol on autophagy in non-small-cell lung cancer (NSCLC) cells have not yet been clearly elucidated.

Materials and methods

A549 and H1299 cells were treated with different concentrations of resveratrol. Cell growth and apoptosis were measured by CCK-8 assay and flow cytometry, respectively. A549 cells were then treated with 200 μM resveratrol or SRT1720. Cell autophagy was detected by western blot and immunofluorescence.

Results

In this study, we found that resveratrol exerted the anti-tumor effect through inhibiting cell proliferation and promoting cell apoptosis in NSCLC cells dose-dependently. Resveratrol has also increased the relative expression of Beclin1 and LC3 II/I while decreased p62 expression, suggesting that resveratrol induced autophagy in NSCLC cells. In addition, resveratrol increased SIRT1 expression and SIRT1 activator SRT1720-induced autophagy of NSCLC cells. SIRT1 knockdown reduced resveratrol-induced autophagy significantly. These results indicated that resveratrol might induce autophagy through upregulating SIRT1 expression. Moreover, inhibiting autophagy by autophagy inhibitor 3-methyladenine or SIRT1 inhibitor nicotinamide significantly suppressed proliferation while promoted apoptosis compared with the resveratrol 200 μM group, suggesting that resveratrol-induced autophagy might act as a protective mechanism to promote NSCLC cell survival and inhibiting autophagy can enhance the anti-tumor effect of resveratrol. Besides that, resveratrol treatment inhibited Akt/mTOR while p38-MAPK was activated in NSCLC cells in a dose-dependent manner. Activating Akt/ mTOR pathway by IGF-1 or inhibiting p-38-MAPK pathway by doramapimod significantly inhibited cell proliferation while increased cell apoptosis of NSCLC cells compared with the resveratrol 200 μM group.

Conclusion

Taken together, our findings suggest that resveratrol inhibited proliferation but induced apoptosis and autophagy via inhibiting Akt/mTOR and activating p38-MAPK pathway. Resveratrol-induced autophagy might act as a protective mechanism to promote NSCLC cell survival. Therefore, inhibition of autophagy may enhance the anti-tumor activity of resveratrol in NSCLC.

Autophagy and its potent modulators from phytochemicals in cancer treatment

Autophagy is a ubiquitous catabolic process by which damaged or harmful intracellular components are delivered to the lysosomes for self-digestion and recycling. It is critical in cancer treatment. Therapy-induced autophagy predominantly acts as a pro-survival mechanism, but progressive autophagy can lead to non-apoptotic cell death, also known as autophagic cell death. Plants or herbs contain various natural compounds that are widely used in the treatment of many types of malignancies. Emerging evidence indicates that phytochemicals targeting the autophagic pathway are promising agents for cancer treatment. However, these compounds play different roles in autophagy. In this review, we discussed the role of autophagy in cancer development and therapy, and focussed on elucidating the anti-cancer activities of autophagic modulators, especially phytochemicals. Notably, we described a novel premise that the dynamic role of phytochemicals should be evaluated in regulation of autophagy in cancer.

Hispidulin induces ER stress-mediated apoptosis in human hepatocellular carcinoma cells in vitro and in vivo by activating AMPK signaling pathway

Hispidulin (4',5,7-trihydroxy-6-methoxyflavone) is a phenolic flavonoid isolated from the medicinal plant S. involucrata, which exhibits anti-neoplastic activity against several types of cancer. However, the mechanism underlying its anti-cancer activity against hepatocellular carcinoma (HCC) has not been fully elucidated. In this study, we investigated whether and how hispidulin-induced apoptosis of human HCC cells in vitro and in vivo. We showed that hispidulin (10, 20 μmol/L) dose-dependently inhibited cell growth and promoted apoptosis through mitochondrial apoptosis pathway in human HCC SMMC7721 cells and Huh7 cells. More importantly, we revealed that its pro-apoptotic effects depended on endoplasmic reticulum stress (ERS) and unfolded protein response (UPR), as pretreatment with salubrinal, a selective ERS inhibitor, or shRNA targeting a UPR protein CHOP effectively abrogated hispidulin-induced cell apoptosis. Furthermore, we showed that hispidulin-induced apoptosis was mediated by activation of AMPK/mTOR signaling pathway as pretreatment with Compound C, an AMPK inhibitor, or AMPK-targeting siRNA reversed the pro-apoptotic effect of hispidulin. In HCC xenograft nude mice, administration of hispidulin (25, 50 mg/kg every day, ip, for 27 days) dose-dependently suppressed the tumor growth, accompanied by inducing ERS and apoptosis in tumor tissue. Taken together, our results demonstrate that hispidulin induces ERS-mediated apoptosis in HCC cells via activating the AMPK/mTOR pathway. This study provides new insights into the anti-tumor activity of hispidulin in HCC.

Triptolide, A Potential Autophagy Modulator

As a major active component extracted from traditional Chinese herb Tripterygium wilfordii Hook F, triptolide exhibits multiple pharmacological effects. Autophagy is an evolutionary conserved intracellular catabolic process involved in cytoplasmic materials degradation. Autophagic dysfunction contributes to the pathologies of many human diseases, which makes it a promising therapeutic target. Recent studies have shown that triptolide exerts neuroprotection, anti-tumor activities, organ toxicity, and podocyte protection by modulating autophagy. This article highlights the current information on triptolide-modulated autophagy, analyzes the possible pathways involved, and describes the crosstalk between autophagy and apoptosis modulated by triptolide, in hope of providing implications for the roles of autophagy in pharmacological effects of triptolide and expanding its novel usage as an autophagy modulator.

Adenosine 5'-monophosphate-activated protein kinase-dependent mTOR pathway is involved in flavokawain B-induced autophagy in thyroid cancer cells

Flavokawain B (FKB), a natural kava chalcone, shows potent antitumor activity in various types of cancer, although the mechanism of action remains unclear. In this study, we report that FKB has profound effects on the metabolic state of human thyroid cancer (TCa) cells, leading to high autophagy flux through upregulation of AMP‐activated protein kinase, which in turn inhibits mTOR and activates Beclin‐1 in TCa cells. We further report that the autophagy induced by FKB plays a prosurvival role in TCa cells both in vitro and in vivo. In conclusion, our findings provide evidence that combination treatment with FKB and pharmacological autophagy inhibitors will be a potential therapeutic strategy for the treatment of TCa.

Triptolide induces protective autophagy and apoptosis in human cervical cancer cells by downregulating Akt/mTOR activation

Triptolide exhibits immunosuppressive, anti-inflammatory, antifertility and antineoplastic functions. However, the anticancer effect of triptolide on cervical cancer and the underlying mechanism remains to be fully understood. The present study assessed the mechanisms underlying the effect of triptolide on the viability and apoptosis of human cervical cancer cells. SiHa cells were treated with 12.5-100.0 nM triptolide for 12, 24 or 48 h. The present study demonstrated that triptolide inhibited viability and induced apoptosis in SiHa cells time- and dose-dependently. Furthermore, treatment with triptolide promoted autophagy and activated microtubule associated protein 1 light chain 3 α expression in SiHa cells. Triptolide treatment suppressed the expression of phosphorylated (p)-protein kinase B (Akt), p-mechanistic target of rapamycin (mTOR), and p-p70S6K, activated the expression of p-p38, mitogen-activated protein kinase (MAPK) and p53 and inhibited the expression of p-forkhead box O3 (Foxo3a) in SiHa cells. These results suggested that triptolide induces protective autophagy, suppresses cell viability and promotes apoptosis in human cervical cancer cells by inducing the autophagy-targeting phosphoinositide 3-kinase/Akt/mTOR, p38, MAPK, p53 and Foxo3a pathways.

Alteration of Androgen Receptor Protein Stability by Triptolide in LNCaP Cells

Background and Objective: Although triptolide was effective for prostate cancer (PCa), the mechanism is still unclear. Androgen receptor (AR) plays a large role in the development and progression of PCa, even after castration. The present study aimed at investigating the effects of triptolide on AR protein stability and the possible mechanism. Materials and Methods: By blocking protein synthesis with cycloheximide (CHX), the effect of triptolide on AR protein stability was investigated with western blot assay. The potential role of calpains in triptolide reduced AR protein stability was investigated with calpain inhibitor and Ca²⁺ chelator. Results: Triptolide down-regulated AR protein level when protein synthesis was blocked by CHX, demonstrating the decrease of AR protein stability. The AR protein level was restored when the cells were co-treated with triptolide and calpain inhibitor or Ca²⁺ chelator, indicating the important role of calpains. Conclusions: The results indicate that triptolide can activate calpain via promoting intracellular Ca²⁺ accumulation, and thus decrease the stability of AR protein, subsequently resulting in the breakdown of the AR protein in LNCaP cells. This work provides an experimental basis and evidence to elucidate the anti-PCa mechanisms of triptolide.

Triptolide-induced mitochondrial damage dysregulates fatty acid metabolism in mouse sertoli cells

Triptolide is a major active ingredient of tripterygium glycosides, used for the therapy of immune and inflammatory diseases. However, its clinical applications are limited by severe male fertility toxicity associated with decreased sperm count, mobility and testicular injures. In this study, we determined that triptoide-induced mitochondrial dysfunction triggered reduction of lactate and dysregulation of fatty acid metabolism in mouse Sertoli cells. First, triptolide induced mitochondrial damage through the suppressing of proliferator-activated receptor coactivator-1 alpha (PGC-1α) activity and protein. Second, mitochondrial damage decreased lactate production and dysregulated fatty acid metabolism. Finally, mitochondrial dysfunction was initiated by the inhibition of sirtuin 1 (SIRT1) with the regulation of AMP-activated protein kinase (AMPK) in Sertoli cells after triptolide treatment. Meanwhile, triptolide induced mitochondrial fatty acid oxidation dysregulation by increasing AMPK phosphorylation. Taken together, we provide evidence that the mechanism of triptolide-induced testicular toxicity under mitochondrial injury may involve a metabolic change.

Berberine induces autophagy in glioblastoma by targeting the AMPK/mTOR/ULK1-pathway

There is an urgent need for new therapeutic strategies for patients with glioblastoma multiforme (GBM). Previous studies have shown that berberine (BBR), a natural plant alkaloid, has potent anti-tumor activity. However, the mechanisms leading to cancer cell death have not been clearly elucidated. In this study, we show that BBR has profound effects on the metabolic state of GBM cells, leading to high autophagy flux and impaired glycolytic capacity. Functionally, these alterations reduce the invasive properties, proliferative potential and induce apoptotic cell death. The molecular alterations preceding these changes are characterized by inhibition of the AMPK/mTOR/ULK1 pathway. Finally, we demonstrate that BBR significantly reduces tumor growth in vivo, demonstrating the potential clinical benefits for autophagy modulating plant alkaloids in cancer therapy.

Triptolide induces autophagy and apoptosis through ERK activation in human breast cancer MCF-7 cells

To investigate the effects of triptolide (TPI) on proliferation, autophagy and death in human breast cancer MCF-7 cells, and to elucidate the associated molecular mechanisms, intracellular alterations were analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays. The results of the MTT assay revealed that TPI significantly reduced the MCF-7 cell survival rate when the concentration was >10 nmol/l. TPI activated a caspase cascade reaction by regulating Bcl-2-associated X protein (Bax), caspase-3 and B-cell lymphoma 2 expression, and promoted programmed cell death via the mitochondrial pathway. The results demonstrated that TPI significantly reduced the cell proliferation rate and viability in a time- and dose-dependent manner, which was confirmed by western blotting and immunofluorescent staining. TPI induced autophagy and influenced p38 mitogen-activated protein kinases, extracellular signal-regulated kinase (Erk)1/2, and mammalian target of rapamycin (mTOR) phosphorylation, which resulted in apoptosis. When cells were treated with a combination of TPI and the Erk1/2 inhibitor U0126, the downregulation of P62 and upregulation of Bax were inhibited, which demonstrated that the inhibition of Erk1/2 reversed the autophagy changes induced by TPI. The results indicated that Erk1/2 activation may be a novel mechanism by which TPI induces autophagy and apoptosis in MCF-7 breast cancer cells. In conclusion, TPI affects the proliferation and apoptosis of MCF-7 cells, potentially via autophagy and p38/Erk/mTOR phosphorylation. The present study offers a novel view of the mechanisms by which TPI regulates cell death.

Salvianolic acid B, a novel autophagy inducer, exerts antitumor activity as a single agent in colorectal cancer cells

Salvianolic Acid B (Sal B), an active compound extracted from the Chinese herb Salvia miltiorrhiza, is attracting more and more attention due to its biological activities, including antioxidant, anticoagulant and antitumor effects. However, autophagy induction in cancer cells by Sal B has never been recognized. In this study, we demonstrated that Sal B induced cell death and triggered autophagy in HCT116 and HT29 cells in a dose-dependent manner. Specific inhibition of autophagy by 3-MA or shRNA targeting Atg5 rescued Sal B-induced cell death in vitro and in vivo, suggesting that Sal B-induced autophagy may play a pro-death role and contribute to the cell death of colorectal cancer cell lines. Furthermore, AKT/mTOR signaling pathway was demonstrated to be a critical mediator in regulating Sal B-induced cell death. Overexpression of AKT by the transfection with AKT plasmid or pretreatment with insulin decreased Sal B-induced autophagy and cell death. Inversely, inhibition of AKT by LY294002 treatment markedly enhanced Sal B-induced autophagy and cell death. Taken together, our results demonstrate, for the first time, that Sal B is a novel autophagy inducer and exerts its antitumor activity as a single agent in colorectal cancer cells through the suppression of AKT/mTOR pathway.

Triptolide suppresses paraquat induced idiopathic pulmonary fibrosis by inhibiting TGFB1-dependent epithelial mesenchymal transition

Idiopathic pulmonary fibrosis (IPF) and tumor are highly similar to abnormal cell proliferation that damages the body. This malignant cell evolution in a stressful environment closely resembles that of epithelial-mesenchymal transition (EMT). As a popular EMT-inducing factor, TGFβ plays an important role in the progression of multiple diseases. However, the drugs that target TGFB1 are limited. In this study, we found that triptolide (TPL), a Chinese medicine extract, exerts an anti-lung fibrosis effect by inhibiting the EMT of lung epithelial cells. In addition, triptolide directly binds to TGFβ and subsequently increase E-cadherin expression and decrease vimentin expression. In in vivo studies, TPL improves the survival state and inhibits lung fibrosis in mice. In summary, this study revealed the potential therapeutic effect of paraquat induced TPL in lung fibrosis by regulating TGFβ-dependent EMT progression.