The suppressive effects of Britannin (Bri) on human liver cancer through inducing apoptosis and autophagy via AMPK activation regulated by ROS

Progress of natural sesquiterpenoids in the treatment of hepatocellular carcinoma

Hepatocellular carcinoma is one of the common malignant tumors of digestive tract, which seriously threatens the life of patients due to its high incidence rate, strong invasion, metastasis, and prognosis. At present, the main methods for preventing and treating HCC include medication, surgery, and intervention, but patients frequently encounter with specific adverse reactions or side effects. Many Traditional Chinese medicine can improve liver function, reduce liver cancer recurrence and have unique advantages in the treatment of HCC because of their acting mode of multi-target, multi-pathway, multi-component, and multi-level. Sesquiterpenoids, a class of natural products which are widely present in nature and exhibit good anti-tumor activity, and many of them possess good potential for the treatment of HCC. This article reviewed the anti-tumor activities, natural resources, pharmacological mechanism of natural sesquiterpenoids against HCC, providing the theoretical basis for the prevention and treatment of HCC and a comprehensive understanding of their potential for development of new clinical drugs.

Britanin - a beacon of hope against gastrointestinal tumors?

Britanin is a bioactive sesquiterpene lactone known for its potent anti-inflammatory and anti-oxidant properties. It also exhibits significant anti-tumor activity, suppressing tumor growth in vitro and in vivo. The current body of research on Britanin includes thirty papers predominantly related to neoplasms, the majority of which are gastrointestinal tumors that have not been summarized before. To drive academic debate, the present paper reviews the available research on Britanin in gastrointestinal tumors. It also outlines novel research directions using data not directly concerned with the digestive system, but which could be adopted in future gastrointestinal research. Britanin was found to counteract liver, colorectal, pancreatic, and gastric tumors, by regulating proliferation, apoptosis, autophagy, immune response, migration, and angiogenesis. As confirmed in pancreatic, gastric, and liver cancer, its most commonly noted molecular effects include nuclear factor kappa B and B-cell lymphoma 2 downregulation, as well as Bcl-2-associated X protein upregulation. Moreover, it has been found to induce the Akt kinase and Forkhead box O1 axis, activate the AMP-activated protein kinase pathway, elevate interleukin-2 and peroxisome proliferator-activated receptor-γ levels, reduce interleukin-10, as well as downregulate matrix metalloproteinase-9, Twist family bHLH transcription factor 1, and cyclooxygenase-2. It also inhibits Myc-HIF1α interaction and programmed death ligand 1 transcription by interrupting the Ras/ RAF/MEK/ERK pathway and mTOR/P70S6K/4EBP1 signaling. Future research should aim to unravel the link between Britanin and acetylcholinesterase, mast cells, osteolysis, and ischemia, as compelling data have been provided by studies outside the gastrointestinal context. Since the cytotoxicity of Britanin on noncancerous cells is significantly lower than that on tumor cells, while still being effective against the latter, further in-depth studies with the use of animal models are merited. The compound exhibits pleiotropic biological activity and offers considerable promise as an anti-cancer agent, which may address the current paucity of treatment options and high mortality rate among patients with gastrointestinal tumors.

Sesquiterpene lactones as emerging biomolecules to cease cancer by targeting apoptosis

Apoptosis is a programmed cell death comprising two signaling cascades including the intrinsic and extrinsic pathways. This process has been shown to be involved in the therapy response of different cancer types, making it an effective target for treating cancer. Cancer has been considered a challenging issue in global health. Cancer cells possess six biological characteristics during their developmental process known as cancer hallmarks. Hallmarks of cancer include continuous growth signals, unlimited proliferation, resistance to proliferation inhibitors, apoptosis escaping, active angiogenesis, and metastasis. Sesquiterpene lactones are one of the large and diverse groups of planet-derived phytochemicals that can be used as sources for a variety of drugs. Some sesquiterpene lactones possess many biological activities such as anti-inflammatory, anti-viral, anti-microbial, anti-malarial, anticancer, anti-diabetic, and analgesic. This review article briefly overviews the intrinsic and extrinsic pathways of apoptosis and the interactions between the modulators of both pathways. Also, the present review summarizes the potential effects of sesquiterpene lactones on different modulators of the intrinsic and extrinsic pathways of apoptosis in a variety of cancer cell lines and animal models. The main purpose of the present review is to give a clear picture of the current knowledge about the pro-apoptotic effects of sesquiterpene lactones on various cancers to provide future direction in cancer therapeutics.

Britannin inhibits cell proliferation, migration and glycolysis by downregulating KLF5 in lung cancer

Lung cancer is a harmful type of malignancy and the leading cause of cancer-associated mortality. It is therefore imperative to develop novel drugs effective for treating this cancer. The Traditional Chinese Medicine compound Britannin has been previously reported to inhibit the development of certain cancers, such as pancreatic, breast and liver cancer. Moreover, Kruppel-like factor 5 (KLF5) has been identified an on oncogene in lung cancer. In the present study, the possible regulatory effects and underlying mechanism of Britannin in lung cancer were investigated. A549 and 16HBE cells were treated with different concentrations of Britannin. Subsequently, Cell counting kit-8, EdU staining and colony formation assays were used to detect the proliferative ability of these cells. Cell migration was detected by wound healing and Transwell assays, respectively. XF96 extracellular flux analyzer was used to analyze the extent of extracellular acidification and oxygen consumption rate in cells, whereas assay kits were used to detect glucose and lactic acid levels in the cell supernatant. The targeting effect between Britannin and the KLF5 protein was investigated using molecular docking technology. The protein expression levels of KLF5 in cells challenged with Britannin was detected by western blotting. Finally, overexpression of KLF5 in A549 cells was performed before cell proliferation, migration and the glycolysis rate were measured to explore the regulatory effects of Britannin. Britannin was found to inhibit the proliferation, migration and glycolysis of lung cancer cells, during which the protein expression levels of KLF5 were decreased. This suggests that Britannin regulated the expression of KLF5 in A549 cells. Overexpression of KLF5 reversed the inhibitory effects of Britannin on the proliferation, migration and glycolysis in lung cancer cells. In conclusion, these results suggest that Britannin can inhibit cell proliferation, migration and glycolysis by downregulating KLF5 expression in lung cancer cells.

Natural products targeting macroautophagy signaling in hepatocellular carcinoma therapy: Recent evidence and perspectives

Hepatocellular carcinoma (HCC), presently the second leading cause of global cancer-related mortality, continues to pose significant challenges in the realm of medical oncology, impacting both clinical drug selection and mechanistic research. Recent investigations have unveiled autophagy-related signaling as a promising avenue for HCC treatment. A growing body of research has highlighted the pivotal role of autophagy-modulating natural products in inhibiting HCC progression. In this context, we provide a concise overview of the fundamental autophagy mechanism and delineate the involvement of autophagic signaling pathways in HCC development. Additionally, we review pertinent studies demonstrating how natural products regulate autophagy to mitigate HCC. Our findings indicate that natural products exhibit cytotoxic effects through the induction of excessive autophagy, simultaneously impeding HCC cell proliferation by autophagy inhibition, thereby depriving HCC cells of essential energy. These effects have been associated with various signaling pathways, including PI3K/AKT, MAPK, AMPK, Wnt/β-catenin, Beclin-1, and ferroautophagy. These results underscore the considerable therapeutic potential of natural products in HCC treatment. However, it is important to note that the present study did not establish definitive thresholds for autophagy induction or inhibition by natural products. Further research in this domain is imperative to gain comprehensive insights into the dual role of autophagy, equipping us with a better understanding of this double-edged sword in HCC management.

Cold atmospheric plasma sensitizes head and neck cancer to chemotherapy and immune checkpoint blockade therapy

Head and neck cancer (HNC) is the seventh most prevalent cancer globally, often characterized by chemo-resistance and immunosuppression, which significantly hampers treatment efficacy. Cold atmospheric plasma (CAP) has recently emerged as a promising adjuvant oncotherapy with substantial potential and advantages. In this study, Piezobrush® PZ2, a handheld CAP unit based on the piezoelectric direct discharge technology, was used to generate and deliver non-thermal plasma. We aimed to investigate the effects of CAPPZ2 on various types of HNC cells and elucidate the underlying mechanisms. In addition, we endeavored to examine the efficacy of combining CAPPZ2 with chemotherapy drugs (i.e., cisplatin) or immune checkpoint blockade (ICB, i.e., PD1 antibody) in HNC treatment. Firstly, the results demonstrated that CAPPZ2 exerted anti-neoplastic functions through inhibiting cell proliferation, migration and invasion, and promoting apoptosis and autophagy. Secondly, using transcriptomic sequencing, Western blotting, and quantitative real-time PCR, the mechanisms underlying CAPPZ2 treatment in vitro was presumed to be a multitargeted blockade of major cancer survival pathways, such as redox balance, glycolysis, and PI3K/AKT/mTOR/HIF-1α signaling. Lastly, combinatorial thearpy containing CAPPZ2 and cisplatin or PD-1 antibody significantly suppressed tumor growth and prolonged recipient survival in vivo. Collectively, the synergistic effects of CAPPZ2 and cisplatin or PD-1 antibody could serve as a promising solution to enhance head and neck tumor elimination.

A Cocktail of Natural Compounds Holds Promise for New Immunotherapeutic Potential in Head and Neck Cancer

OBJECTIVE

To obtain detailed understanding on the gene regulation of natural compounds in altering prognosis of head and neck squamous cell carcinomas (HNSC).

METHODS

Gene expression data of HNSC samples and peripheral blood mononuclear cells (PBMCs) of HNSC patients were collected from Gene Expression Omnibus (GEO). Differential gene expression analysis of GEO datasets were achieved by the GEO2R tool. Common differentially expressed gerres (DEGs) were screened by comparing DEGs of HNSC with those of PBMCs. The combination was further analyzed for regulating pathways and biological processes that were affected.

RESULTS

Totally 110 DEGs were retrieved and identified to be involved in biological processes related to tumor regulation. Then 102 natural compounds were screened for a combination such that the expression of all 110 commonly DEGs was altered. A combination of salidroside, ginsenoside Rd, oridonin, britanin, and scutellarein was chosen. A multifaceted, multi-dimensional tumor regression was showed by altering autophagy, apoptosis, inhibiting cell proliferation, angiogenesis, metastasis and inflammatory cytokines production.

CONCLUSIONS

This study has helped develop a unique combination of natural compounds that will markedly reduce the propensity of development of drug resistance in tumors and immune evasion by tumors. The result is crucial to developing a combinatorial natural therapeutic cocktail with accentuated immunotherapeutic potential.

Research progress on antitumor mechanisms and molecular targets of Inula sesquiterpene lactones

The pharmacological effects of natural product therapy have received sigificant attention, among which terpenoids such as sesquiterpene lactones stand out due to their biological activity and pharmacological potential as anti-tumor drugs. Inula sesquiterpene lactones are a kind of sesquiterpene lactones extracted from Inula species. They have many pharmacological activities such as anti-inflammation, anti-asthma, anti-tumor, neuroprotective and anti-allergic. In recent years, more and more studies have proved that they are important candidate drugs for the treatment of a variety of cancers because of its good anti-tumor activity. In this paper, the structure, structure-activity relationship, antitumor activities, mechanisms and targets of Inula sesquiterpene lactones reported in recent years were reviewed in order to provide clues for the development of novel anticancer drugs.

Targeting the Interplay of Autophagy and ROS for Cancer Therapy: An Updated Overview on Phytochemicals

Autophagy is an evolutionarily conserved self-degradation system that recycles cellular components and damaged organelles, which is critical for the maintenance of cellular homeostasis. Intracellular reactive oxygen species (ROS) are short-lived molecules containing unpaired electrons that are formed by the partial reduction of molecular oxygen. It is widely known that autophagy and ROS can regulate each other to influence the progression of cancer. Recently, due to the wide potent anti-cancer effects with minimal side effects, phytochemicals, especially those that can modulate ROS and autophagy, have attracted great interest of researchers. In this review, we afford an overview of the complex regulatory relationship between autophagy and ROS in cancer, with an emphasis on phytochemicals that regulate ROS and autophagy for cancer therapy. We also discuss the effects of ROS/autophagy inhibitors on the anti-cancer effects of phytochemicals, and the challenges associated with harnessing the regulation potential on ROS and autophagy of phytochemicals for cancer therapy.

Targeting PPARγ/ NF-κB Signaling Pathway by Britannin, a Sesquiterpene Lactone from Inula aucheriana DC., in Gastric Cancer

BACKGROUND

Gastric cancer is one of the most common and deadliest malignancies in the world. Therefore, there is an urgent need to develop new and effective agents to reduce mortality. The plants of genus Inula have gained the attention of researchers worldwide as a rich source of potent medicinal compounds.

OBJECTIVE

This study explores the anti-cancer activity of Britannin, a sesquiterpene lactone isolated from Inula aucheriana DC., and its molecular mechanism in gastric cancer cells, AGS and MKN45.

METHODS

Cytotoxicity was evaluated through the MTT assay following 24 h, 48 h, and 72 h treatment with different concentrations of Britannin. Apoptosis rate and caspase-3 activity were measured 24 h after treatment by Britannin. . Western blotting was performed to determine the expression of the NF-κB, IκBα, and PPARγ proteins. Moreover, quantitative RT-PCR was applied to measure the expression of NF-κB target genes.

RESULTS

We showed that Britannin induced cell growth inhibition and apoptosis in gastric cancer cells. Britannin caused an elevation in mRNA and protein levels of PPARγ. The involvement of PPARγ was more confirmed using GW9662, a PPARγ inhibitor. Suppression of NF-κB was demonstrated by western blot analysis. Down-regulation of MMP-9, TWIST-1, COX-2, and Bcl-2 and up-regulation of Bax were also observed in gastric cancer cells.

CONCLUSION

These results imply that activation of the PPARγ signaling pathway through suppression of NF-κB underlies the anti-cancer properties of Britannin in gastric cancer. Therefore, Britannin could be considered as a promising anti-cancer candidate for further evaluation.

Study on inhibition of Britannin on triple-negative breast carcinoma through degrading ZEB1 proteins

BACKGROUND

Triple-negative breast carcinomas (TNBCs) are a breast carcinoma with the most aggressive form, which is demonstrated as enhanced invasion and recurrence. Britannin is extracted mainly from the traditional Chinese herb Inula japonica Thunb, and few studies have focused on its effect on TNBC. Moreover, there is still no report concerning the role of Britannin in degrading the transcripts of Zinc finger E-box-binding homeobox 1 (ZEB1) proteins.

PURPOSE

To explore the potential effect of Britannin on invasion and stemness of TNBCs and its underlying mechanism.

METHODS

Cellular activity was measured using MTT, and cell cycle was measured using flow cytometry (FCM). The effect of Britannin on the migrating and invading abilities of MDA-MB-231 and 4T1 cells were measured using the wound healing and transwell assays. The sizes and number of breast carcinoma cells were measured by tumor formation assay and in vitro limiting-dilution assay. CD44 expression in tumor spheroids was tested by immunofluorescence assay. Nextly, the expressions of epithelial-mesenchymal transition (EMT) markers and ZEB1 protein expressional level were detected by western blot . ZEB1 mRNA expressional level was analyzed using RT-qPCR. Drug affinity-responsive target stability (DARTS) method was used to detect the binding activity between Britannin and ZEB1. Co-immunoprecipitation (Co-IP) analysis was applied to test the ubiquitination of ZEB1. The mouse models for experimental lung metastasis of 4T1 cells were established to detect the anti-metastasis effect of Britannin in vivo, and the expressional levels of EMT markers in lung metastases were detected by immunohistochemistry.

RESULTS

Britannin could inhibit cell growth and G2/M arrest in TNBC cells. Britannin could inhibit the migrating and invading ability without inducing severe apoptosis of MDA-MB-231 and 4T1 cells. Meanwhile, Britannin reduced the size and number of spheroids formed in these two cells, and decreased the expressional level of stem cells biomarker CD44 in tumor spheroids. Mechanism research showed that Britannin specifically bound to ZEB1 and induced its ubiquitination in MDA-MB-231 cells. Afterwards, Britannin disturbed protein stability and promoted ZEB1 protein degradation. Importantly, Britannin could not inhibit cell invasion and spheroid formation after ZEB1 expression was knocked down. Finally, Britannin inhibition of 4T1 cell metastasis was confirmed through establishing mouse models for the experimental lung metastasis. It was proved that both Britannin and paclitaxel could decrease the lung metastases, and Britannin could also down-regulate the protein expressional levels of ZEB1, MMP9 and CD44.

CONCLUSION

This study reveals that Britannin suppresses the invasion and metastasis of TNBC cells through degrading ZEB1, which suggests that Britannin can be used to prevent tumor metastasis and recurrence via degrading ZEB1proteins.

Integrative Analysis of Transcriptome and Metabolome Reveals Molecular Responses in Eriocheir sinensis with Hepatopancreatic Necrosis Disease

Hepatopancreatic necrosis disease (HPND) is a highly lethal disease that first emerged in 2015 in Jiangsu Province, China. So far, most researchers believe that this disease is caused by abiotic factors. However, its true pathogenic mechanism remains unknown. In this study, the effects of HPND on the metabolism and other biological indicators of the Chinese mitten crab (Eriocheir sinensis) were evaluated by integrating transcriptomics and metabolomics. Our findings demonstrate that the innate immunity, antioxidant activity, detoxification ability, and nervous system of the diseased crabs were affected. Additionally, metabolic pathways such as lipid metabolism, nucleotide metabolism, and protein metabolism were dysregulated, and energy production was slightly increased. Moreover, the IL-17 signaling pathway was activated and high levels of autophagy and apoptosis occurred in diseased crabs, which may be related to hepatopancreas damage. The abnormal mitochondrial function and possible anaerobic metabolism observed in our study suggested that functional hypoxia may be involved in HPND progression. Furthermore, the activities of carboxylesterase and acetylcholinesterase were significantly inhibited, indicating that the diseased crabs were likely stressed by pesticides such as pyrethroids. Collectively, our findings provide new insights into the molecular mechanisms altered in diseased crabs, as well as the etiology and pathogenic mechanisms of HPND.

Anticancer Targets and Signaling Pathways Activated by Britannin and Related Pseudoguaianolide Sesquiterpene Lactones

Sesquiterpene lactones (SLs) are abundant in plants and display a large spectrum of bioactivities. The compound britannin (BRT), found in different Inula species, is a pseudoguaianolide-type SL equipped with a typical and highly reactive α-methylene-γ-lactone moiety. The bioproperties of BRT and related pseudoguaianolide SLs, including helenalin, gaillardin, bigelovin and others, have been reviewed. Marked anticancer activities of BRT have been evidenced in vitro and in vivo with different tumor models. Three main mechanisms are implicated: (i) interference with the NFκB/ROS pathway, a mechanism common to many other SL monomers and dimers; (ii) blockade of the Keap1-Nrf2 pathway, with a covalent binding to a cysteine residue of Keap1 via the reactive α-methylene unit of BRT; (iii) a modulation of the c-Myc/HIF-1α signaling axis leading to a downregulation of the PD-1/PD-L1 immune checkpoint and activation of cytotoxic T lymphocytes. The non-specific reactivity of the α-methylene-γ-lactone moiety with the sulfhydryl groups of proteins is discussed. Options to reduce or abolish this reactivity have been proposed. Emphasis is placed on the capacity of BRT to modulate the tumor microenvironment and the immune-modulatory action of the natural product. The present review recapitulates the anticancer effects of BRT, some central concerns with SLs and discusses the implication of the PD1/PD-L1 checkpoint in its antitumor action.

Britannin, a sesquiterpene lactone induces ROS-dependent apoptosis in NALM-6, REH, and JURKAT cell lines and produces a synergistic effect with vincristine

BACKGROUND

Britannin, a Sesquiterpene Lactone isolated from Inula aucheriana, has recently gained attraction in the therapeutic fields due to its anti-tumor properties. This study was designed to evaluate the effect of this agent on Acute Lymphoblastic Leukemia (ALL) cell lines, either as a monotherapy or in combination with Vincristine (VCR).

METHODS AND RESULTS

To determine the anti-leukemic effects of Britannin on ALL-derived cell lines and suggest a mechanism of action for the agent, we used MTT assay, Annexin-V/PI staining, ROS assay, and real-time PCR analysis. Moreover, by using a combination index (CI), we evaluated the synergistic effect of Britannin on Vincristine. We found that unlike normal Peripheral Blood Mononuclear Cells (PBMCs) and L929 cells, Britannin reduced the viability of NALM-6, REH, and JURKAT cells. Among tested cells, NALM-6 cells had the highest sensitivity to Britannin, and this agent was able to induce p21/p27-mediated G1 cell cycle arrest and Reactive Oxygen Specious (ROS)-mediated apoptotic cell death in this cell line. When NALM-6 cells were treated with Nacetyl-L-Cysteine (NAC), a scavenger of ROS, Britannin could induce neither apoptosis nor reduce the survival of the cells suggesting that the cytotoxic effect of Britannin is induced through ROS-dependent manner. Moreover, we found that a low dose of Britannin enhanced the effect of Vincristine in NALM-6 cells by inducing apoptotic cell death via altering the expression of apoptotic-related genes.

CONCLUSIONS

Overall, our results proposed a mechanism for the cytotoxic effect of Britannin, either as a single agent or in combination with Vincristine, in NALM-6 cells.

Exposure to Fluoride induces apoptosis in liver of ducks by regulating Cyt-C/Caspase 3/9 signaling pathway

Fluorine being a well-known and essential element for normal physiological functions of tissues of different organisms is frequently used for growth and development of body. The mechanisms of adverse and injurious impacts of fluoride are not clear and still are under debate. Therefore, this study was executed to ascertain the potential mechanisms of sodium fluoride in liver tissues of ducks. For this purpose, a total of 14 ducks were randomly divided and kept in two groups including control group and sodium fluoride treated group. The ducks in control group were fed with normal diet while the ducks in other group were exposed to sodium fluoride (750 mg/kg) for 28 days. The results showed that exposure to sodium fluoride induced deleterious effects in different liver tissues of ducks. The results indicated that mRNA levels of Cas-3, Cas-9, p53, Apaf-1, Bax and Cyt-c were increased in treated ducks with significantly higher mRNA level of Cas-9 and lower levels of the mRNA level of Bcl-2 as compared to untreated control group (P < 0.01). The results showed that protein expression levels of Bax and p53 were increased while protein expression level of Bcl-2 was reduced in treated ducks. No difference was observed in protein expression level of Cas-3 between treated and untreated ducks. The results of this study suggest that sodium fluoride damages the normal structure of liver and induces abnormal process of apoptosis in hepatocyte, which provide a new idea for elucidating the mechanisms of sodium fluoride induced hepatotoxicity in ducks.

Britannin a Sesquiterpene Lactone from Inula aucheriana Exerted an Anti-leukemic Effect in Acute Lymphoblastic Leukemia (ALL) Cells and Enhanced the Sensitivity of the Cells to Vincristine

Since chemotherapy drugs have dose-related side effects, there is still a need for finding new agents with suitable cytotoxic effects without any harmful effects. For this purpose, we evaluated the cytotoxic effects of Britannin that is a Sesquiterpene Lactone compound Inula aucheriana, alone or in combination with Vincristine (VCR), on Acute Lymphoblastic Leukemia (ALL)-derived MOLT-4 cells. In this study, we found that Britannin decreased the viability of MOLT-4 cells with the IC50 Values of 2 µM, but had no cytotoxic effects on normal cells or Peripheral Blood Mononuclear Cells (PBMCs). Our results also showed that Britannin decreased the proliferation of MOLT-4 cells by preventing the transition of the cells from the S phase of the cell cycle through the up-regulation of p21 and p27. Moreover, this agent induced ROS-mediated apoptosis by altering the expression of Bax, Bim, Caspase3, Bcl2, and XIAP. Britannin also produced a synergistic effect with Vincristine in MOLT-4 cells. Taken together, the results of this study showed for the first time that Britannin, as a natural Sesquiterpene Lactone, has cytotoxic effects that could be considered as an anti-leukemic agent in the treatment of ALL. However, there is still a demand for further studies that examine the efficacy and the safety of this purified compound.

Autoantibody against angiotensin II type I receptor induces pancreatic β-cell apoptosis via enhancing autophagy

Autoantibody against the angiotensin II type I receptor (AT1-AA) has been found in the serum of patients with diabetes mellitus (DM). However, it remains unclear whether AT1-AA induces β-cell apoptosis and participates in the development of DM. In this study, an AT1-AA-positive rat model was set up by active immunization, and AT1-AA IgG was purified. INS-1 cells were treated with AT1-AA, and cell viability, apoptosis, and autophagy-related proteins were detected by Cell Counting Kit-8 assay, flow cytometry, and western blot analysis, respectively. Results showed that existence of AT1-AA impaired the islet function and increased the apoptosis of pancreatic islet cells in rats, and the autophagy level in rat pancreatic islet tissues tended to increase gradually with the prolongation of immunization time. AT1-AA markedly reduced INS-1 cell viability, promoted cell apoptosis, and decreased insulin secretion in vitro. In addition, the autophagy level was gradually increased along with the prolongation of AT1-AA treatment time. Meanwhile, it was determined that treatment with autophagy inhibitor 3-methyladenine and angiotensin II type 1 receptor (AT1R) blocker telmisartan could improve insulin secretion and apoptosis in vitro and in vivo. In conclusion, it is deduced that upregulation of autophagy contributed to the AT1-AA-induced β-cell apoptosis and islet dysfunction, and AT1R mediated the signal transduction.

The Most Competent Plant-Derived Natural Products for Targeting Apoptosis in Cancer Therapy

Cancer is a challenging problem for the global health community, and its increasing burden necessitates seeking novel and alternative therapies. Most cancers share six basic characteristics known as "cancer hallmarks", including uncontrolled proliferation, refractoriness to proliferation blockers, escaping apoptosis, unlimited proliferation, enhanced angiogenesis, and metastatic spread. Apoptosis, as one of the best-known programmed cell death processes, is generally promoted through two signaling pathways, including the intrinsic and extrinsic cascades. These pathways comprise several components that their alterations can render an apoptosis-resistance phenotype to the cell. Therefore, targeting more than one molecule in apoptotic pathways can be a novel and efficient approach for both identifying new anticancer therapeutics and preventing resistance to therapy. The main purpose of this review is to summarize data showing that various plant extracts and plant-derived molecules can activate both intrinsic and extrinsic apoptosis pathways in human cancer cells, making them attractive candidates in cancer treatment.

Anticancer mechanism of breviscapine in non-small cell lung cancer A549 cells acts via ROS-mediated upregulation of IGFBP4

Background

The overall 5-year survival rate of non-small cell lung cancer (NSCLC) is less than 15% because of multiple drug resistance to chemotherapy and the limitations of early diagnosis. Thus, safe and effective drugs to treat NSCLC are required. The present study aimed to investigate the effects of breviscapine (BVP) on NSCLC cell apoptosis and proliferation, and to study its possible mechanisms.

Methods

Using the NSCLC A549 cell line and BVP (0, 25, 50, and 100 µM), the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to detect A549 cell proliferation, and flow cytometry was used to assess cell apoptosis. Insulin-like growth factor binding protein 4 (IGFBP4) levels was assessed using enzyme-linked immunosorbent assays and western blotting. Flow cytometry of hydrogen peroxide and superoxide was used to assess intracellular reactive oxygen species (ROS) generation. Western blotting was used to assess the levels of BCL2-associated X, apoptosis regulator (BAX) and B-cell CLL/lymphoma 2 (BCL2). Quantitative real-time reverse transcription PCR (qRT-PCR) was used to assess IGFBP4 mRNA expression.

Results

BVP induced apoptosis, inhibited cell proliferation, and increased ROS in A549 cells. Western blotting and qRT-PCR showed that BVP increased IGFBP4 protein and mRNA expressions in A549 cells. Compared with BVP treatment alone, IGFBP4 expression decreased in A549 cells treated with BVP and the ROS scavenger N-acetylcysteine. IGFBP4 overexpression increased BVP-induced proliferation inhibition, while increasing BAX expression and decreasing BCL2 expression. Silencing IGFBP4 had the opposite effects.

Conclusions

BVP could inhibit the growth of NSCLC A549 cells by promoting apoptosis via ROS-mediated upregulation of IGFBP4.

Investigating the Opposing Effect of Two Different Green Tea Supplements on Oxidative Stress, Mitochondrial Function and Cell Viability in HepG2 Cells

Green tea extract (GTE) improves exercise outcomes and reduces obesity. However, case studies indicate contradictory physiology regarding liver function and toxicity. We studied the effect of two different decaffeinated GTE (dGTE) products, from a non-commercial (dGTE1) and commercial (dGTE2) supplier, on hepatocyte function using the human cell model, HepG2. dGTE1 was protective against hydrogen peroxide (H₂O₂)-induced apoptosis and cell death by attenuating oxidative stress pathways. Conversely, dGTE2 increased cellular and mitochondrial oxidative stress and apoptosis. A bioavailability study with dGTE showed the major catechin in GTE, EGCG, reached 0.263 µg·ml^-1. In vitro, at this concentration, EGCG mimicked the protective effect of dGTE1. GC/MS analysis identified steric acid and higher levels of palmitic acid in dGTE2 versus dGTE1 supplements. We demonstrate the significant biological differences between two GTE supplements which may have potential implications for manufacturers and consumers to be aware of the biological effects of supplementation.

Role of ALDH2 in Hepatic Disorders: Gene Polymorphism and Disease Pathogenesis

Aldehyde dehydrogenase 2 (ALDH2) is a key enzyme of alcohol metabolism and it is involved in the cellular mechanism of alcohol liver disease. ALDH2 gene mutations exist in about 8% of the world's population, with the incidence reaching 45% in East Asia. The mutations will result in impairment of enzyme activity and accumulation of acetaldehyde, facilitating the progression of other liver diseases, including non-alcoholic fatty liver diseases, viral hepatitis and hepatocellular carcinoma, through adduct formation and inflammatory responses. In this review, we seek to summarize recent research progress on the correlation between ALDH2 gene polymorphism and multiple liver diseases, with an attempt to provide clues for better understanding of the disease mechanism and for strategy making.

The Role of Autophagy in Liver Cancer: Crosstalk in Signaling Pathways and Potential Therapeutic Targets

Autophagy is an evolutionarily conserved lysosomal-dependent pathway for degrading cytoplasmic proteins, macromolecules, and organelles. Autophagy-related genes (Atgs) are the core molecular machinery in the control of autophagy, and several major functional groups of Atgs coordinate the entire autophagic process. Autophagy plays a dual role in liver cancer development via several critical signaling pathways, including the PI3K-AKT-mTOR, AMPK-mTOR, EGF, MAPK, Wnt/β-catenin, p53, and NF-κB pathways. Here, we review the signaling pathways involved in the cross-talk between autophagy and hepatocellular carcinoma (HCC) and analyze the status of the development of novel HCC therapy by targeting the core molecular machinery of autophagy as well as the key signaling pathways. The induction or the inhibition of autophagy by the modulation of signaling pathways can confer therapeutic benefits to patients. Understanding the molecular mechanisms underlying the cross-link of autophagy and HCC may extend to translational studies that may ultimately lead to novel therapy and regimen formation in HCC treatment.

microRNA-519d Induces Autophagy and Apoptosis of Human Hepatocellular Carcinoma Cells Through Activation of the AMPK Signaling Pathway via Rab10

Background and Aim

Hepatocellular carcinoma (HCC) is a type of cancer with high mortality rates. The overexpression of microRNA-519d (miR-519d) has been explored in different types of cancers, which could significantly help suppress cancer development. This study aimed to investigate the interaction of miR-519d with its target gene, Rab10, as well as its effects on cell proliferation and autophagy in HCC cells through modulation of the AMPK signaling pathway.

Methods

Microarray analysis was used to analyze the differentially expressed genes in HCC, and the target genes of the screened-out miRNA were predicted and verified. The expression of miR-519d and Rab10, AMPK signaling pathway-related proteins, apoptosis- and autophagy-related proteins was determined by RT-qPCR and Western blot analysis in HCC tissues and cell lines. Lastly, the effects of miR-519d and Rab10 in HCC cell proliferation, apoptosis, and mouse tumour xenograft in vivo were examined through gain- and loss-of-function experiments.

Results

MiR-519d was down-regulated and Rab10 was upregulated in HCC tissues and cell lines. Overexpression of miR-519d decreased the expression of Rab10, mTOR, and Bcl-2, but increased the expression of Bax, Beclin1, Atg5, and p53. Upregulated miR-519d and downregulated Rab10 expression suppressed cell proliferation and induced cell apoptosis and autophagy in HCC cells. Finally, upregulation of miR-519d inhibited tumour growth in vivo.

Conclusion

The result obtained in this study indicates that up-regulation of miR-519d inhibits proliferation and promotes apoptosis and autophagy of HCC cells through activation of the AMPK signaling pathway via downregulating Rab10, which provides a potential target for the treatment of HCC.

Quercetin induced NUPR1-dependent autophagic cell death by disturbing reactive oxygen species homeostasis in osteosarcoma cells

Osteosarcoma is a primary bone aggressive cancer, affecting adolescents worldwide. Quercetin (a natural polyphenolic compound) is a polyphenolic flavonoid compound found in a variety of plants. It has been demonstrated to exert cytostatic activity against a variety of human cancer, including the human osteosarcoma. However, its efficacy in the treatment of osteosarcoma and the underlying antitumor mechanism has not been fully elucidated yet. In this study, we exposed MG-63 cells to different concentrations of quercetin (50, 100 and 200 µM) for 24 h. Here, we show that quercetin increased autophagic flux in the MG-63 cells, as evidenced by the upregulation of LC3B-II/LC3B-I and downregulation of P62/SQSTM1. Moreover, the autophagy inhibitor Bafilomycin A1 or genetic blocking autophagy with ATG5 knockdown decreased quercetin-induced cell death, indicating quercetin triggered autophagic cell death in MG-63 cells. Specifically, quercetin increased NUPR1 expression and activated of NUPR1 reporter activity, which contributed to the expression of autophagy-related genes and subsequent initiated autophagic cell death in osteosarcoma cells. Importantly, the increased expression NUPR1 were tightly related to the disturbance of reactive oxygen species (ROS) homeostasis, which could be prevented by inhibiting intracellular ROS with NAC. Finally, NAC also abolished quercetin-induced autophagic cell death in vivo. Taken together, these data demonstrate that quercetin induces osteosarcoma cell death via inducing excessive autophagy, which is mediated through the ROS-NUPR1 pathway. Quercetin application may be a promising and practical strategy for osteosarcoma treatment in clinical practice.

ZEA-induced autophagy in TM4 cells was mediated by the release of Ca2+ activates CaMKKβ-AMPK signaling pathway in the endoplasmic reticulum

Zearalenone (ZEA) is a prevalent non-steroidal estrogenic mycotoxin produced mainly by Fusarium contamination. Our previous study showed that ZEA induces the autophagy of Sertoli cells (SCs). However, the underlying mechanisms are still unknown. Several studies have indicated that the increasing level of cytoplasmic Ca²⁺ could induce autophagy through CaMKKβ and AMPK pathways. Thus in order to investigate the potential mechanism underlying ZEA-induced autophagy, the activity of calmodulin-dependent kinase kinase β(CaMKKβ)and AMP-activated protein kinase (AMPK) signaling pathway in ZEA-infected TM4 cells was studied. In the present study, ZEA activated the CaMKKβ and AMPK signaling pathways. The AMPK inhibitor and activator significantly inhibited and stimulated the effect of ZEA on AMPK, the transformation from LC3I to LC3II, and the distribution of LC3 dots. In addition, cytosolic calcium (Ca²⁺) was increased gradually with the concentration of ZEA. After treatment of ZEA-infected cells with 1, 2-bis (2-aminophenoxy) ethane-N, N, N', N'- tetraacetic acid- tetraac etoxymethyl ester (BAPTA-AM) and 2-aminoethyl diphenylborinate (2-APB), the intracellular concentration of Ca²⁺ reduced significantly. Also, the activities of CaMKKβ and AMPK and subsequent autophagy decreased. Moreover, the antioxidant NAC significantly decreased activities of AMPK and autophagy -related protein. Therefore, it can be speculated that ROS- mediated ER-stress induced by ZEA activates AMPK via Ca²⁺-CaMKKβ leading to autophagy in TM4 cells.

Liquiritin inhibits proliferation and induces apoptosis in HepG2 hepatocellular carcinoma cells via the ROS-mediated MAPK/AKT/NF-κB signaling pathway

Liquiritin (LIQ), a major constituent of Glycyrrhiza Radix, exhibits various pharmacological activities. In this study, to explore the potential anti-cancer effects and its underlying molecular mechanisms of LIQ in hepatocellular carcinoma (HCC) cells. LIQ significantly decreased viability and induced apoptosis in HepG2 cells by decreasing mitochondrial membrane potential and regulating Bcl-2 family proteins, cytochrome c, cle-caspase-3, and cle-PARP. The cell cycle analysis and western blot analysis revealed that LIQ induced G2/M phase arrest through increased expression of p21 and decreased levels of p27, cyclin B, and CDK1/2. The flow cytometry and western blot analysis also suggested that LIQ promoted the accumulation of ROS in HepG2 cells and up-regulated the phosphorylation expression levels of p38 kinase, c-Jun N-terminal kinase (JNK), and inhibitor of NF-κB (IκB-α); the phosphorylation levels of extracellular signal-regulated kinase (ERK), protein kinase B (AKT), signal transducer activator of transcription 3 (STAT3), and nuclear factor kappa B (NF-κB) were down-regulated. However, these effects were reversed by N-acetyl-L-cysteine (NAC), MAPK, and AKT inhibitors. The findings demonstrated that LIQ induced cell cycle arrest and apoptosis via the ROS-mediated MAPK/AKT/NF-κB signaling pathway in HepG2 cells, and the LIQ may serve as a potential therapeutic agent for the treatment of human HCC.

The Upstream Pathway of mTOR-Mediated Autophagy in Liver Diseases

Autophagy, originally found in liver experiments, is a cellular process that degrades damaged organelle or protein aggregation. This process frees cells from various stress states is a cell survival mechanism under stress stimulation. It is now known that dysregulation of autophagy can cause many liver diseases. Therefore, how to properly regulate autophagy is the key to the treatment of liver injury. mechanistic target of rapamycin (mTOR)is the core hub regulating autophagy, which is subject to different upstream signaling pathways to regulate autophagy. This review summarizes three upstream pathways of mTOR: the phosphoinositide 3-kinase (PI3K)/protein kinase (AKT) signaling pathway, the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway, and the rat sarcoma (Ras)/rapidly accelerated fibrosarcoma (Raf)/mitogen-extracellular activated protein kinase kinase (MEK)/ extracellular-signal-regulated kinase (ERK) signaling pathway, specifically explored their role in liver fibrosis, hepatitis B, non-alcoholic fatty liver, liver cancer, hepatic ischemia reperfusion and other liver diseases through the regulation of mTOR-mediated autophagy. Moreover, we also analyzed the crosstalk between these three pathways, aiming to find new targets for the treatment of human liver disease based on autophagy.

Interplay Between Autophagy and Apoptosis in Lycorine Hydrochloride-Induced Cytotoxicity of HCT116 Cells

The aim of this study was to investigate the antitumor effect of lycorine hydrochloride (LH) and discuss the correlation between LH-induced apoptosis and autophagy in the human colorectal cancer cell line HCT116. Here the results by the Cell Counting Kit-8 and colony formation assays showed that LH concentration-dependently decreased cell viability and colony formation in HCT116 cells, suggesting inhibition of cell proliferation by LH. By flow cytometry, LH was found to increase apoptotic rate in HCT116 cells. Mechanistically, Western blot results revealed that LH increased the expression of the protein of Bax and Caspase-3, and decreased Bcl-2 proteins expression. Moreover, the reverse transcriptase quantitative polymerase chain reaction and Western blot analysis also showed that LH increased the expression of Beclin-1 and LC3B-II/LC3B-I ratio, indicating that autophagy was induced by LH. LH induced autophagy via downregulating phospho-mammalian target of rapamycin and upregulating phospho-AMPK (5′ adenosine monophosphate-activated protein kinase). Furthermore, to understand the role of LH-induced autophagy and its association with apoptosis, cells were analyzed after Beclin-1 small interfering RNA transfection. The results indicated that the proapoptotic ability of LH was increased by inhibition of autophagy. In conclusion, the present investigation suggested that LH induced apoptosis and autophagy in HCT116 cells via the mitochondrial and AMPK/mTOR pathways. The suppression of autophagy promoted LH-induced apoptosis by modulating Beclin-1 and Bcl-2.

Arsenic and sulfur dioxide co-exposure induce renal injury via activation of the NF-κB and caspase signaling pathway

Although emerging evidence suggests positive association of arsenic (As) or sulfur dioxide (SO₂) exposure with human diseases, reports concerning the effects of co-exposure of As and SO₂ are lacking. Moreover, there is insufficient information in the literature about As and SO₂ co-exposure to renal injury. In this study, we focus on the environmental problems of excessive As and SO₂ that co-exist in many coal consumption areas. We used both C57BL/6 mice and 293T cells to detect toxicities of As and SO₂ exposure alone or in combination. Our results showed that co-exposure significantly increased the hazard compared with exposure to As or SO₂ alone. Mouse kidney tissue slices showed that co-exposure caused more severe diffuse sclerosing glomerulonephritis than As and SO₂ exposure alone. Meanwhile experiments showed that apoptosis was aggravated by co-exposure of As and SO₂ in 293T cells. Because As and SO₂ cause cell toxicity through increasing oxidative stress, next we detected ROS and other oxidative stress parameters, and the results showed oxidative stress was increased by co-exposure compared with the other three groups. The expression levels of downstream genes in the NF-κB and caspase pathways were higher in the co-exposure group than in the groups of As or SO₂ exposure alone in mice and 293T cells. Based on the above results, co-exposure could induce higher toxicity in vitro and in vivo compared with single exposure to As or SO₂, indicating that people living in places that contaminated by As and SO₂ may have higher chance to get renal injury.

Alantolactone induces gastric cancer BGC-823 cell apoptosis by regulating reactive oxygen species generation and the AKT signaling pathway

Alantolactone (ALT), a natural sesquiterpene lactone, has been suggested to exert anti-cancer activities in various cancer cell lines. However, the effects and mechanisms of action of ALT in human gastric cancer remains to be elucidated. In the present study, the effects of ALT on BGC-823 cells were examined and the underlying molecular mechanisms associated with these effects were investigated. Cell viability was detected by using an MTT assay. Cell cycle, cell apoptosis and the level of reactive oxygen species (ROS) were assessed by flow cytometry, and the expression levels of proteins of interest were analyzed by western blot assay. The results demonstrated that ALT triggered apoptosis and induced G0/G1 phase arrest in a dose-dependent manner. Furthermore, the expression level of the anti-apoptosis protein Bcl-2 was downregulated, and expression of the pro-apoptosis proteins Bax and cleaved PARP were significantly upregulated. The cell cycle-associated proteins cyclin-dependent kinase inhibitor 1 and cyclin-dependent kinase inhibitor 1B were also increased, while cyclin D1 was deceased. In addition, ALT induced apoptosis via the inhibition of RAC-alpha serine/threonine-protein kinase (AKT) signaling and ROS generation, which was effectively inhibited by the ROS scavenger, N-acetyl cysteine. Therefore, the results from the present study indicated that the ROS-mediated inhibition of the AKT signaling pathway serves an important role in ALT-induced apoptosis in BGC-823 cells. In conclusion, the results demonstrated that ALT exerted significant anti-cancer effects against gastric cancer cells in vitro.

Ginger polysaccharides induced cell cycle arrest and apoptosis in human hepatocellular carcinoma HepG2 cells

In this study, ginger polysaccharide (GP) was obtained from ginger by enzymatic method, its chemical properties and antitumor activity were investigated. The results indicated that the composition and proportion of GP were l‑rhamnose, d‑arabinose, d‑mannose, d‑glucose and d‑galactose in a molar ratio of 3.64:5.37:3.04:61.03:26.91, GP had the characteristic absorption peak of polysaccharide. Congo red experiment showed that GP had a triple helix structure, which could have anti-tumor effect. Furthermore, MTT assay, cell morphology observation, nuclear morphology observation and reactive oxygen species observation demonstrated that GP had significant antitumor effect. Flow cytometry suggested that GP could promote apoptosis and arrest cells in G0-G1 phase. Real-time fluorescence quantification and Western blot revealed that GP could up-regulate the expression of Bax, Fas, FasL, caspase-3, p21 and p53, and down-regulate the expression of Bcl-2. These studies suggested that GP would be used as an antitumor drug in foods to promote the development of functional foods.

Chlorpyrifos Induction of Testicular-Cell Apoptosis through Generation of Reactive Oxygen Species and Phosphorylation of AMPK

Chlorpyrifos (CPF) is the most frequently applied insecticide. Aside from effects on the neuronal cholinergic system, previous studies suggested a potential relationship between CPF exposure and male infertility; however, the molecular mechanism remains elusive. The aim of this study was to investigate the toxic effect of CPF on testicular cells and the potential mechanism via in vitro and in vivo experiments. The cytotoxic effects of CPF on mouse-derived spermatogonial cell lines (GC-1), Sertoli cell lines (TM4) and Leydig cell lines (TM3) were assessed by a CCK-8 assay, flow cytometry, a TUNEL assay, quantitative RT-PCR, and Western blotting. Exposure to CPF (10-50 μM) for 12 or 24 h resulted in significant death in all three testicular cell lines. The number of TUNEL-positive apoptotic cells were dose-dependent and increased with raised CPF concentrations. Further investigation indicated that CPF induced cell-cycle arrest and then promoted cell apoptosis. Additionally, CPF increased reactive-oxygen-species (ROS) production and lipid peroxidation (MDA) and reduced mitochondrial-membrane potential. The mechanism of cell apoptosis induced by CPF involved an increase in phosphorylated-AMP-activated-protein-kinase (p-AMPK) levels in the tested cells. In vivo, the expression of steroid-hormone-biosynthesis-related genes in testis, spleen, and lung in F0 and F1 mice were downregulated when there was intraperitoneal injection or dietary supplementation of CPF. This study provides a potential molecular mechanism of CPF-induced toxicity in testicular cells and a theoretical basis for future treatment of male infertility.