Apigetrin inhibits gastric cancer progression through inducing apoptosis and regulating ROS-modulated STAT3/JAK2 pathway

Enzymatic synthesis of phenolic acid glucosyl esters to test activities on cholangiocarcinoma cells

While glycoside hydrolase family 1 (GH1) enzymes mostly catalyze hydrolysis reactions, rice Os9BGlu31 preferentially catalyzes transglycosylation to transfer a glucosyl moiety to another aglycone moiety to form a new glycosylated compound through a retaining mechanism. In this study, Os9BGlu31 was used to synthesize eight phenolic acid glucosyl esters, which were evaluated for activities in cholangiocarcinoma cells. The transglycosylation products of Os9BGlu31 wild type and its mutant variants were detected, produced on a milligram scale, and purified, and their structures were characterized by NMR spectroscopy. The transglycosylation products were evaluated by antioxidant and anti-proliferative assays, followed by an anti-migration assay for the selected phenolic acid glucosyl ester. Os9BGlu31 mutants produced higher yield and activity than wild-type enzymes on phenolic acids to produce phenolic acid glucosyl esters. Among these, gallic acid glucosyl ester (β-glucogallin) had the highest antioxidant activity and anti-proliferative activity in cholangiocarcinoma cells. It also inhibited the migration of cholangiocarcinoma cells. Our study demonstrated that rice Os9BGlu31 transglucosidase is a promising enzyme for glycosylation of bioactive compounds in one-step reactions and provides evidence that β-glucogallin inhibits cell proliferation and migration of cholangiocarcinoma cells. KEY POINTS: • Os9BGlu31 transglucosidases produced phenolic acid glucosyl esters for bioactivity testing. • Phenolic acid glucosyl esters were tested for cytotoxicity in cholangiocarcinoma cells. • β-Glucogallin displayed the highest inhibition of cholangiocarcinoma cell growth.

Effect of apigetrin in pseudo-SARS-CoV-2-induced inflammatory and pulmonary fibrosis in vitro model

SARS-CoV-2 has become a global public health problem. Acute respiratory distress syndrome (ARDS) is the leading cause of death due to the SARS-CoV-2 infection. Pulmonary fibrosis (PF) is a severe and frequently reported COVID-19 sequela. In this study, an in vitro model of ARDS and PF caused by SARS-CoV-2 was established in MH-S, THP-1, and MRC-5 cells using pseudo-SARS-CoV-2 (PSCV). Expression of proinflammatory cytokines (IL-6, IL-1β, and TNF-α) and HIF-1α was increased in PSCV-infected MH-S and THP-1 cells, ARDS model, consistent with other profiling data in SARS-CoV-2-infected patients have been reported. Hypoxia-inducible factor-1 alpha (HIF-1α) siRNA and cobalt chloride were tested using this in vitro model. HIF-1α knockdown reduces inflammation caused by PSCV infection in MH-S and THP-1 cells and lowers elevated levels of CTGF, COLA1, and α-SMA in MRC-5 cells exposed to CPMSCV. Furthermore, apigetrin, a glycoside bioactive dietary flavonoid derived from several plants, including Crataegus pinnatifida, which is reported to be a HIF-1α inhibitor, was tested in this in vitro model. Apigetrin significantly reduced the increased inflammatory cytokine (IL-6, IL-1β, and TNF-α) expression and secretion by PSCV in MH-S and THP-1 cells. Apigetrin inhibited the binding of the SARS-CoV-2 spike protein RBD to the ACE2 protein. An in vitro model of PF induced by SARS-CoV-2 was produced using a conditioned medium of THP-1 and MH-S cells that were PSCV-infected (CMPSCV) into MRC-5 cells. In a PF model, CMPSCV treatment of THP-1 and MH-S cells increased cell growth, migration, and collagen synthesis in MRC-5 cells. In contrast, apigetrin suppressed the increase in cell growth, migration, and collagen synthesis induced by CMPSCV in THP-1 and MH-S MRC-5 cells. Also, compared to control, fibrosis-related proteins (CTGF, COLA1, α-SMA, and HIF-1α) levels were over two-fold higher in CMPSV-treated MRC-5 cells. Apigetrin decreased protein levels in CMPSCV-treated MRC-5 cells. Thus, our data suggest that hypoxia-inducible factor-1 alpha (HIF-1α) might be a novel target for SARS-CoV-2 sequela therapies and apigetrin, representative of HIF-1alpha inhibitor, exerts anti-inflammatory and PF effects in PSCV-treated MH-S, THP-1, and CMPVSC-treated MRC-5 cells. These findings indicate that HIF-1α inhibition and apigetrin would have a potential value in controlling SARS-CoV-2-related diseases.

Apigenin: Molecular Mechanisms and Therapeutic Potential against Cancer Spreading

Due to its propensity to metastasize, cancer remains one of the leading causes of death worldwide. Thanks in part to their intrinsic low cytotoxicity, the effects of the flavonoid family in the prevention and treatment of various human cancers, both in vitro and in vivo, have received increasing attention in recent years. It is well documented that Apigenin (4',5,7-trihydroxyflavone), among other flavonoids, is able to modulate key signaling molecules involved in the initiation of cancer cell proliferation, invasion, and metastasis, including JAK/STAT, PI3K/Akt/mTOR, MAPK/ERK, NF-κB, and Wnt/β-catenin pathways, as well as the oncogenic non-coding RNA network. Based on these premises, the aim of this review is to emphasize some of the key events through which Apigenin suppresses cancer proliferation, focusing specifically on its ability to target key molecular pathways involved in angiogenesis, epithelial-to-mesenchymal transition (EMT), maintenance of cancer stem cells (CSCs), cell cycle arrest, and cancer cell death.

Liquid chromatography-tandem mass spectrometry profile and antioxidant, antimicrobial, antiproliferative, and enzyme activities of Thymus pectinatus and Thymus convolutus: in vitro and in silico approach

BACKGROUND

The objective of this study is to investigate the antiproliferative, antioxidant, antimicrobial, and enzyme activity capacities and phytochemical compositions of Thymus pectinatus (TP), Thymus convolutus (TC), which are endemic to Türkiye. Quantitative analysis of phenolic compounds in the extracts was conducted using liquid chromatography-tandem mass spectrometry, targeting 53 phenolic compounds.

RESULTS

Rosmarinic acid, quinic acid, and cynaroside were identified as the major compounds, exhibiting quantitative variation in both extracts. The extracts had a high total phenolic content, with 113.57 ± 0.58 mg gallic acid equivalents (GAE)/g extract for TP and 130.52 ± 1.05 mg GAE/g extract for TC. Furthermore, although both extracts exhibited high total flavonoid content; the TP extract (75.12 ± 1.65 mg quercitin equivalents (QE)/g extract) displayed a higher flavonoid content than the TC extract (30.24 ± 0.74 mg QE/g extract) did. The extracts had a promising antiproliferative effect on C6, HeLa, and HT29 cancer cell lines with a less cytotoxic effect (10.5-14.2%) against normal cells. Both extracts exhibited very potent inhibitory activity against the xanthine oxidase enzyme, with half-maximal inhibitory concentration values of respectively 2.07 ± 0.03 μg mL-1 and 2.76 ± 0.06 μg mL-1 and moderate activity against tyrosinase and α-glucosidase. Docking simulations proved that rosmarinic acid and cynaroside, the major components of the extracts, were the most potent inhibitors of xanthine oxidase. According to antimicrobial activity results, the TC extract exhibited moderate activity against Staphylococcus aureus, and the TP extract had strong activity against both Enterococcus faecium and S. aureus.

CONCLUSION

These findings emphasize the beneficial effects of the two endemic Thymus species on human health and suggest their potential use as plant-derived bioactive agents. © 2024 Society of Chemical Industry.

Apigetrin ameliorates doxorubicin prompted testicular damage: biochemical, spermatological and histological based study

Doxorubicin (DOX) is a highly effective, commonly prescribed, potent anti-neoplastic drug that damages the testicular tissues and leads to infertility. Apigetrin (APG) is an important flavonoid that shows diverse biological activities. The present research was designed to evaluate the alleviative role of APG against DOX-induced testicular damages in rats. Forty-eight adult male albino rats were randomly distributed into 4 groups, control, DOX administered (3 mgkg-1), DOX + APG co-administered (3 mgkg-1 of DOX; 15 mgkg-1 of APG), and APG administered group (15 mgkg-1). Results of the current study indicated that DOX treatment significantly reduced the activities of superoxide dismutase (SOD), glutathione reductase (GSR), catalase (CAT) and glutathione peroxidase (GPx), while increasing the levels of malondialdehyde (MDA) and reactive oxygen species (ROS). DOX treatment also reduced the sperm count, viability, and motility. Moreover, DOX significantly increased the sperm morphological anomalies and reduced the levels of plasma testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The administration of DOX significantly increased the expressions of Bax and Caspase-3, as well as the levels of inflammatory markers. Additionally, DOX treatment significantly downregulated the expressions of steroidogenic enzymes (StAR, 3β-HSD and 17β-HSD) and Bcl-2. Furthermore, DOX administration provoked significant histopathological abnormalities in the testicular tissues. However, APG supplementation significantly reversed all the testicular damages due to its androgenic, anti-apoptotic, anti-oxidant and anti-inflammatory nature. Therefore, it is concluded that APG may prove a promising therapeutic agent to treat DOX-induced testicular damages.

Natural products for gastric carcinoma prevention and treatment: Focus on their antioxidant stress actions in the Correa's cascade

BACKGROUND

Correa's cascade is a pathological process beginning from gastritis to gastric precancerous lesions, and finally to gastric carcinoma (GC). While the pathogenesis of GC remains unclear, oxidative stress plays a prominent role throughout the entire Correa's cascade process. Studies have shown that some natural products (NPs) could halt and even reverse the development of the Correa's cascade by targeting oxidative stress.

METHODS

To review the effects and mechanism by which NPs inhibit the Correa's cascade through targeting oxidative stress, data were collected from PubMed, Embase, Web of Science, ScienceDirect, and China National Knowledge Infrastructure databases from initial establishment to April 2023. NPs were classified and summarized by their mechanisms of action.

RESULTS

NPs, such as terpenoid, polyphenols and alkaloids, exert multistep antioxidant stress effects on the Correa's cascade. These effects include preventing gastric mucosal inflammation (stage 1), reversing gastric precancerous lesions (stage 2), and inhibiting gastric carcinoma (stage 3). NPs can directly impact the conversion of gastritis to GC by targeting oxidative stress and modulating signaling pathways involving IL-8, Nrf2, TNF-α, NF-κB, and ROS/MAPK. Among which polyphenols have been studied more and are of high research value.

CONCLUSIONS

NPs display a beneficial multi-step action on the Correa's cascade, and have potential value for clinical application in the prevention and treatment of gastric cancer by regulating the level of oxidative stress.

The signaling pathways and targets of natural products from traditional Chinese medicine treating gastric cancer provide new candidate therapeutic strategies

Gastric cancer (GC) is one of the severe malignancies with high incidence and mortality, especially in Eastern Asian countries. Significant advancements have been made in diagnosing and treating GC over the past few decades, resulting in tremendous improvements in patient survival. In recent years, traditional Chinese medicine (TCM) has garnered considerable attention as an alternative therapeutic approach for GC due to its multicomponent and multitarget characteristics. Consequently, natural products found in TCM have attracted researchers' attention, as growing evidence suggests that these natural products can impede GC progression by regulating various biological processes. Nevertheless, their molecular mechanisms are not systematically uncovered. Here, we review the major signaling pathways involved in GC development. Additionally, clinical GC samples were analyzed. Moreover, the anti-GC effects of natural products, their underlying mechanisms and potential targets were summarized. These summaries are intended to facilitate further relevant research, and accelerate the clinical applications of natural products in GC treatment.

LncTUG1 promotes hepatocellular carcinoma immune evasion via upregulating PD-L1 expression

HCC is one of the most common malignant tumors worldwide. Although traditional treatment methods have been improved in recent years, the survival rate of HCC patients has not been significantly improved. Immunotherapy has shown extremely high clinical value in a variety of tumors. In this study, we found that TUG1 could regulate the expression of PD-L1 through JAK2/STAT3 to mediate immunosuppression. Here, The expression of TUG1 and PD-L1 in HCC tissues was evaluated through analysis of databases and verified in HCC tissue and HCC cancer cells by qRT-PCR. The effect of TUG1 on tumor immune escape was detected by coculture, and cell viability was detected with a CCK8 assay. The results demonstrated that TUG1 was closely associated with anticancer immunity. TUG1 and PD-L1 were highly expressed in HCC tissues and HCC cancer cells, and high expression of TUG1 and PD-L1 was related to the poor prognosis of HCC patients. In addition, knocking down TUG1 expression could reduce PD-L1 expression and enhance the cancer cell-killing capability of T cells. Downregulating TUG1 expression could also decrease the mRNA and protein expression of JAK2 and STAT3. To sum up, TUG1 and PD-L1 are overexpressed in patients with liver cancer and are related to the poor prognosis of these patients. Silencing TUG1 expression reduced the mRNA and protein expression of PD-L1 by affecting the JAK2/STAT3 pathway.

Reactive oxygen species, toxicity, oxidative stress, and antioxidants: chronic diseases and aging

A physiological level of oxygen/nitrogen free radicals and non-radical reactive species (collectively known as ROS/RNS) is termed oxidative eustress or "good stress" and is characterized by low to mild levels of oxidants involved in the regulation of various biochemical transformations such as carboxylation, hydroxylation, peroxidation, or modulation of signal transduction pathways such as Nuclear factor-κB (NF-κB), Mitogen-activated protein kinase (MAPK) cascade, phosphoinositide-3-kinase, nuclear factor erythroid 2-related factor 2 (Nrf2) and other processes. Increased levels of ROS/RNS, generated from both endogenous (mitochondria, NADPH oxidases) and/or exogenous sources (radiation, certain drugs, foods, cigarette smoking, pollution) result in a harmful condition termed oxidative stress ("bad stress"). Although it is widely accepted, that many chronic diseases are multifactorial in origin, they share oxidative stress as a common denominator. Here we review the importance of oxidative stress and the mechanisms through which oxidative stress contributes to the pathological states of an organism. Attention is focused on the chemistry of ROS and RNS (e.g. superoxide radical, hydrogen peroxide, hydroxyl radicals, peroxyl radicals, nitric oxide, peroxynitrite), and their role in oxidative damage of DNA, proteins, and membrane lipids. Quantitative and qualitative assessment of oxidative stress biomarkers is also discussed. Oxidative stress contributes to the pathology of cancer, cardiovascular diseases, diabetes, neurological disorders (Alzheimer's and Parkinson's diseases, Down syndrome), psychiatric diseases (depression, schizophrenia, bipolar disorder), renal disease, lung disease (chronic pulmonary obstruction, lung cancer), and aging. The concerted action of antioxidants to ameliorate the harmful effect of oxidative stress is achieved by antioxidant enzymes (Superoxide dismutases-SODs, catalase, glutathione peroxidase-GPx), and small molecular weight antioxidants (vitamins C and E, flavonoids, carotenoids, melatonin, ergothioneine, and others). Perhaps one of the most effective low molecular weight antioxidants is vitamin E, the first line of defense against the peroxidation of lipids. A promising approach appears to be the use of certain antioxidants (e.g. flavonoids), showing weak prooxidant properties that may boost cellular antioxidant systems and thus act as preventive anticancer agents. Redox metal-based enzyme mimetic compounds as potential pharmaceutical interventions and sirtuins as promising therapeutic targets for age-related diseases and anti-aging strategies are discussed.

Inhibition of Cell Proliferation and Cell Death by Apigetrin through Death Receptor-Mediated Pathway in Hepatocellular Cancer Cells

Epidemiologic research recommends using flavonoids in the diet due to their overall health benefits. Apigetrin (Apigenin 7-O-glucoside) is a glycoside phytonutrient found in fruits and vegetables and known for different biological activities such as antioxidant and anti-inflammatory properties. Hepatocellular cancer (HCC) is a major health concern because of its adverse prognosis and side effects of chemotherapeutic agents. In the present study, we determine the impact of apigetrin on HepG2 cells and its cell death mechanism. Apigetrin reduced HepG2 cell proliferation with morphological changes and floating cells in treated cells. Colony formation and wound healing assays showed a reduced cell number in treatment groups. Further, we checked for the cell cycle through flow cytometry to understand the cell death mechanism. Apigetrin induced G2/M phase arrest in HepG2 cells by regulating Cyclin B1 and CDK1 protein levels in HepG2 cells. Annexin V and propidium iodide (PI) staining was performed to confirm the apoptotic cell population in treated groups. At the higher concentration, apigetrin showed a late apoptotic population in HepG2 cells. Chromatin condensation was also found in the treatment groups. Western blot analysis showed an increased expression of extrinsic apoptotic proteins such as FasL, Cleaved caspase 8, Cleaved caspase 3, and cleavage of PARP. In comparison, intrinsic apoptotic pathway markers showed no changes in Bax, Bcl-xL, and Cleaved caspase 9. Altogether, these findings strongly indicate that apigetrin causes cell death in HepG2 cells through the extrinsic apoptotic pathway, and that the intrinsic/mitochondrial pathway is not involved.

Natural products targeting signaling pathways associated with regulated cell death in gastric cancer: Recent advances and perspectives

Gastric cancer (GC) is one of the most serious gastrointestinal malignancies with high morbidity and mortality. The complexity of GC process lies in the multi-phenotypic linkage regulation, in which regulatory cell death (RCD) is the core link, which largely dominates the fate of GC cells and becomes a key determinant of GC development and prognosis. In recent years, increasing evidence has been reported that natural products can prevent and inhibit the development of GC by regulating RCDs, showing great therapeutic potential. In order to further clarify its key regulatory characteristics, this review focused on specific expressions of RCDs, combined with a variety of signaling pathways and their crosstalk characteristics, sorted out the key targets and action rules of natural products targeting RCD. It is highlighted that a variety of core biological pathways and core targets are involved in the decision of GC cell fate, including the PI3K/Akt signaling pathway, MAPK-related signaling pathways, p53 signaling pathway, ER stress, Caspase-8, gasdermin D (GSDMD), and so on. Moreover, natural products target the crosstalk of different RCDs by modulating above signaling pathways. Taken together, these findings suggest that targeting various RCDs in GC with natural products is a promising strategy, providing a reference for further clarifying the molecular mechanism of natural products treating GC, which warrants further investigations in this area.

Anticancer applications of phytochemicals in gastric cancer: Effects and molecular mechanism

Gastric cancer (GC) is the fourth most common malignant cancer and is a life-threatening disease worldwide. Phytochemicals have been shown to be a rational, safe, non-toxic, and very promising approach to the prevention and treatment of cancer. It has been found that phytochemicals have protective effects against GC through inhibiting cell proliferation, inducing apoptosis and autophagy, suppressing cell invasion and migration, anti-angiogenesis, inhibit Helicobacter pylori infection, regulating the microenvironment. In recent years, the role of phytochemicals in the occurrence, development, drug resistance and prognosis of GC has attracted more and more attention. In order to better understand the relationship between phytochemicals and gastric cancer, we briefly summarize the roles and functions of phytochemicals in GC tumorigenesis, development and prognosis. This review will probably help guide the public to prevent the occurrence and development of GC through phytochemicals, and develop functional foods or drugs for the prevention and treatment of gastric cancer.

Thermo-Transient Receptor Potential Channels: Therapeutic Potential in Gastric Cancer

Over the last decade, researchers have found abnormal expression of transient receptor potential (TRP) channels. In particular, members of the thermally sensitive subclass (thermo-TRPs) are involved in many disease processes. Moreover, they have a vital role in the occurrence and development of gastric cancer (GC). Accordingly, thermo-TRPs constitute a major pharmacological target, and the elucidation of the mechanisms underlying their response to physiological stimuli or drugs is key for notable advances in GC treatment. Therefore, this paper summarizes the existing literature about thermo-TRP protein expression changes that are linked to the incidence and progression of GC. The review also discusses the implication of such association to pathology and cell physiology and identifies potential thermo-TRP protein targets for diagnosis and treatment of GC.

Molecular mechanisms underlying the action of carcinogens in gastric cancer with a glimpse into targeted therapy

BACKGROUND

Gastric cancer imposes a substantial global health burden despite its overall incidence decrease. A broad spectrum of inherited, environmental and infectious factors contributes to the development of gastric cancer. A profound understanding of the molecular underpinnings of gastric cancer has lagged compared to several other tumors with similar incidence and morbidity rates, owing to our limited knowledge of the role of carcinogens in this malignancy. The International Agency for Research on Cancer (IARC) has classified gastric carcinogenic agents into four groups based on scientific evidence from human and experimental animal studies. This review aims to explore the potential comprehensive molecular and biological impacts of carcinogens on gastric cancer development and their interactions and interferences with various cellular signaling pathways.

CONCLUSIONS

In this review, we highlight recent clinical trial data reported in the literature dealing with different ways to target various carcinogens in gastric cancer. Moreover, we touch upon other multidisciplinary therapeutic approaches such as surgery, adjuvant and neoadjuvant chemotherapy. Rational clinical trials focusing on identifying suitable patient populations are imperative to the success of single-agent therapeutics. Novel insights regarding signaling pathways that regulate gastric cancer can potentially improve treatment responses to targeted therapy alone or in combination with other/conventional treatments. Preventive strategies such as control of H. pylori infection through eradication or immunization as well as dietary habit and lifestyle changes may reduce the incidence of this multifactorial disease, especially in high prevalence areas. Further in-depth understanding of the molecular mechanisms involved in the role of carcinogenic agents in gastric cancer development may offer valuable information and update state-of-the-art resources for physicians and researchers to explore novel ways to combat this disease, from bench to bedside. A schematic outlining of the interaction between gastric carcinogenic agents and intracellular pathways in gastric cancer H. pylori stimulates multiple intracellular pathways, including PI3K/AKT, NF-κB, Wnt, Shh, Ras/Raf, c-MET, and JAK/STAT, leading to epithelial cell proliferation and differentiation, apoptosis, survival, motility, and inflammatory cytokine release. EBV can stimulate intracellular pathways such as the PI3K/Akt, RAS/RAF, JAK/STAT, Notch, TGF-β, and NF-κB, leading to cell survival and motility, proliferation, invasion, metastasis, and the transcription of anti-apoptotic genes and pro-inflammatory cytokines. Nicotine and alcohol can lead to angiogenesis, metastasis, survival, proliferation, pro-inflammatory, migration, and chemotactic by stimulating various intracellular signaling pathways such as PI3K/AKT, NF-κB, Ras/Raf, ROS, and JAK/STAT. Processed meat contains numerous carcinogenic compounds that affect multiple intracellular pathways such as sGC/cGMP, p38 MAPK, ERK, and PI3K/AKT, leading to anti-apoptosis, angiogenesis, metastasis, inflammatory responses, proliferation, and invasion. Lead compounds may interact with multiple signaling pathways such as PI3K/AKT, NF-κB, Ras/Raf, DNA methylation-dependent, and epigenetic-dependent, leading to tumorigenesis, carcinogenesis, malignancy, angiogenesis, DNA hypermethylation, cell survival, and cell proliferation. Stimulating signaling pathways such as PI3K/Akt, RAS/RAF, JAK/STAT, WNT, TGF-β, EGF, FGFR2, and E-cadherin through UV ionizing radiation leads to cell survival, proliferation, and immortalization in gastric cancer. The consequence of PI3K/AKT, NF-κB, Ras/Raf, ROS, JAK/STAT, and WNT signaling stimulation by the carcinogenic component of Pickled vegetables and salted fish is the Warburg effect, tumorigenesis, angiogenesis, proliferation, inflammatory response, and migration.

Achillea moschata Wulfen: From Ethnobotany to Phytochemistry, Morphology, and Biological Activity

A multidisciplinary investigation on Achillea moschata Wulfen (Asteraceae) is outlined herein. This work, part of the European Interreg Italy-Switzerland B-ICE project, originated from an ethnobotanical survey performed in Chiesa in Valmalenco (Sondrio, Lombardy, Northern Italy) in 2019-2021 which highlighted this species' relevance of use in folk medicine to treat gastrointestinal diseases. In addition, this contribution included analyses of the: (a) phytochemical profile of the aqueous and methanolic extracts of the dried flower heads using LC-MS/MS; (b) morpho-anatomy and histochemistry of the vegetative and reproductive organs through Light, Fluorescence, and Scanning Electron Microscopy; (c) biological activity of the aqueous extract concerning the antioxidant and anti-inflammatory potential through cell-based in vitro models. A total of 31 compounds (5 phenolic acids, 13 flavonols, and 13 flavones) were detected, 28 of which included in both extracts. Covering and secreting trichomes were observed: the biseriate 10-celled glandular trichomes prevailing on the inflorescences represented the main sites of synthesis of the polyphenols and flavonoids detected in the extracts, along with volatile terpenoids. Finally, significant antioxidant and anti-inflammatory activities of the aqueous extract were documented, even at very low concentrations; for the first time, the in vitro tests allowed us to formulate hypotheses about the mechanism of action. This work brings an element of novelty due to the faithful reproduction of the traditional aqueous preparation and the combination of phytochemical and micromorphological research approaches.

LINC00629, a KLF10-responsive lncRNA, promotes the anticancer effects of apigenin by decreasing Mcl1 stability in oral squamous cell carcinoma

Apigenin, a naturally occurring flavonoid, is known to exhibit antitumor activity in many cancers. However, the regulatory mechanism of apigenin and the long noncoding RNAs (lncRNAs) altered upon apigenin treatment in oral squamous cell carcinoma (OSCC) remain unclear. In this study, we found that LINC00629 was significantly upregulated in response to apigenin treatment. Upregulated LINC00629 enhanced the growth-suppressive and proapoptotic effects of apigenin on OSCC cells by interacting with Mcl1 and facilitating its degradation. Subsequently, our data indicated that KLF10, an important transcription factor, directly bound to the promoter of LINC00629, facilitating its transcription and contributing to apigenin-induced LINC00629 expression. Collectively, these results suggest that the KLF10-LINC00629-Mcl1 axis plays an important role in the anticancer effects of apigenin.

Apigetrin Promotes TNFα-Induced Apoptosis, Necroptosis, G2/M Phase Cell Cycle Arrest, and ROS Generation through Inhibition of NF-κB Pathway in Hep3B Liver Cancer Cells

Apigetrin (7-(β-D-glucopyranosyloxy)-4′,5-dihydroxyflavone), a glycoside bioactive dietary flavonoid derived from Taraxacum officinale and Teucrium gnaphalodes, is known to possess anticancer, antioxidant, and anti-inflammatory effects on numerous cancers. In the present study, we examined the effect of apigetrin in Hep3B hepatocellular cancer cell line (HCC). Apigetrin inhibited cell growth and proliferation of Hep3B cells, as confirmed by MTT and colony formation assay. We used apigetrin at concentrations of 0, 50, and 100 µM for later experiments. Of these concentrations, 100 µM of apigetrin showed a significant effect on cell inhibition. In apigetrin-treated Hep3B cells, cell cycle arrest occurred at the G2/M phase. Apoptosis and necroptosis of Hep3B cells treated with apigetrin were confirmed by Annexin V/propidium iodide (PI) staining and flow cytometry results. Morphological observation through 4′,6-diamidino-2-phenylindole (DAPI) staining showed intense blue fluorescence representing chromatin condensation. Hematoxylin staining showed necroptotic features such as formation of vacuoles and swelling of organelles. Apigetrin increased reactive oxygen species (ROS) levels in cells, based on fluorescence imaging. Furthermore, the underlying mechanism involved in the apoptosis and necroptosis was elucidated through western blotting. Apigetrin up-regulated TNFα, but down-regulated phosphorylation of p-p65, and IκB. Apigetrin inhibited the expression of Bcl-xl but increased Bax levels. Up-regulation of cleaved PARP and cleaved caspase 3 confirmed the induction of apoptosis in apigetrin-treated Hep3B cells. Additionally, necroptosis markers RIP3, p-RIP3, and p-MLKL were significantly elevated by apigetrin dose-dependently, suggesting necroptotic cell death. Taken together, our findings strongly imply that apigetrin can induce apoptosis and necroptosis of Hep3B hepatocellular cancer cells. Thus, apigetrin as a natural compound might have potential for treating liver cancer.

AKT, a Key Transmitter of HIF-1α and AR Signaling Pathways, Has a Critical Role in the Apigetrin-Mediated Anti-Cancer Effects in Prostate Cancer Cells

Apigetrin is a flavonoid glycoside phytochemical that is derived from various herbs and exhibits several beneficial biological activities, including anti-oxidant, anti-inflammatory, anti-obesity, and anti-cancer effects. In the present study, we elucidated the anti-cancer effect and targeting mechanism of apigetrin in LNCaP and PC-3 cells through various experiments, including cell viability by CELLOMAX^TM Viability Assay kit, cell migration by scratch wound assays, and 2D-and 3D- cell growth assay. Apigetrin inhibited the viability, migration, proliferation, and growth of cells in long-term 2D- and 3D- cultures cell growth. A high dose of apigetrin induced apoptosis, as evidenced by increased cleavage of poly ADP-ribose polymerase (PARP) and caspase-3 (c-cas3) in both LNCaP and PC-3 cells. Furthermore, apigetrin inhibited AR, PSA, HIF-1α, and VEGF expression in LNCaP and PC-3 cells. Apigetrin also suppressed the hypoxia-induced HIF-1α expression in these cells. Furthermore, apigetrin reduced hypoxia-induced VEGF secretion in the culture medium and inhibited hypoxia-induced tube formation of HUVECs. Silencing of AKT revealed that the anti-cancer activity of apigetrin is mediated via AKT. Thus, our data suggest that apigetrin exerts anti-cancer effects by inhibiting AKT, a central key of HIF-1α and AR signaling, in early-and late-stage prostate cancer cells.

Apigetrin Abrogates Lipopolysaccharide-Induced Inflammation in L6 Skeletal Muscle Cells through NF-κB/MAPK Signaling Pathways

Apigetrin is a glycosidic flavonoid derived from Teucrium gnaphalodes that has a wide range of biological activities, including antioxidant, anti-inflammatory, and anticancer. Inflammation is a kind of defense mechanism in the body. Flavonoids are natural phytochemicals that exert anti-inflammatory effects in numerous cells. In the present study, we investigated the anti-inflammatory effect of apigetrin and its underlying mechanism of activity in skeletal muscle cells (L6). The determination of cytotoxicity was performed by MTT assay. We treated L6 cells with apigetrin, and nontoxic concentrations were chosen to perform further experimentation. Apigetrin inhibited the expression of iNOS and COX-2 induced by LPS in a dose-dependent manner. iNOS and COX-2 are inflammatory markers responsible for enhancing the inflammatory response. Apigetrin also inhibited the LPS-induced phosphorylation of p65 and IκB-α. NF-κB signaling regulates the inflammatory process by mediating various proinflammatory genes. Similarly, the MAPK signaling pathway consists of ERK, JNK, and p38, which plays a critical role in the production of cytokines and downstream signaling events leading to inflammation. Apigetrin significantly downregulated the phosphorylation of JNK and p38, but did not affect the phosphorylation of ERK in the LPS-stimulated cells. These findings indicate the correlation between the anti-inflammatory activity of NF-κB and the MAPK signaling pathway. Thus, our overall finding suggests that apigetrin has anti-inflammatory effects and it can be considered for further drug design on L6 skeletal muscle cells.

Brassinin Enhances Apoptosis in Hepatic Carcinoma by Inducing Reactive Oxygen Species Production and Suppressing the JAK2/STAT3 Pathway

Plants from the family Brassicaceae produce brassinin (BSN), which is an essential indole phytoalexin. BSN can kill certain types of cancer cells. Using hepatocarcinoma (HCC) cells, we examined the molecular mechanisms of BSN. We found that HCC cell growth was suppressed and apoptosis was induced by BSN via the downregulation of the JAK/STAT3 pathway. The cytoplasmic latent transcription factor STAT3, belonging to the STAT family, acted as both a signal transducer and an activator and was linked to tumor progression and decreased survival. BSN incubation caused HCC cells to produce reactive oxygen species (ROS). By activating caspase-9/-3 and PARP cleavage, Bcl-2 was reduced, and apoptosis was increased. BSN inhibited constitutive STAT3, JAK2, and Src phosphorylation. The JAK/STAT signaling cascade was confirmed by siRNA silencing STAT3 in HCC cells. BSN also suppressed apoptosis by Z-Val-Ala-Asp-Fluoromethylketone (Z-VAD-FMK), an apoptotic inhibitor. N-acetylcysteine (NAC) inhibited the production of ROS and diminished BSN-induced apoptosis. Our findings suggested that BSN has potential as a treatment for cancer.

Capsicum Leaves under Stress: Using Multi-Omics Analysis to Detect Abiotic Stress Network of Secondary Metabolism in Two Species

The plant kingdom contains an enormous diversity of bioactive compounds which regulate plant growth and defends against biotic and abiotic stress. Some of these compounds, like flavonoids, have properties which are health supporting and relevant for industrial use. Many of these valuable compounds are synthesized in various pepper (Capsicum sp.) tissues. Further, a huge amount of biomass residual remains from pepper production after harvest, which provides an important opportunity to extract these metabolites and optimize the utilization of crops. Moreover, abiotic stresses induce the synthesis of such metabolites as a defense mechanism. Two different Capsicum species were therefore exposed to chilling temperature (24/18 ℃ vs. 18/12 ℃), to salinity (200 mM NaCl), or a combination thereof for 1, 7 and 14 days to investigate the effect of these stresses on the metabolome and transcriptome profiles of their leaves. Both profiles in both species responded to all stresses with an increase over time. All stresses resulted in repression of photosynthesis genes. Stress involving chilling temperature induced secondary metabolism whereas stresses involving salt repressed cell wall modification and solute transport. The metabolome analysis annotated putatively many health stimulating flavonoids (apigetrin, rutin, kaempferol, luteolin and quercetin) in the Capsicum biomass residuals, which were induced in response to salinity, chilling temperature or a combination thereof, and supported by related structural genes of the secondary metabolism in the network analysis.

Targeting STAT3 Signaling Facilitates Responsiveness of Pancreatic Cancer Cells to Chemoradiotherapy

The debate is ongoing regarding the potential role of preoperative chemoradiotherapy (CRT) for patients with pancreatic ductal adenocarcinoma (PDAC), and whether it should be reserved for borderline resectable or unresectable tumors. However, treatment response is heterogeneous, implicating the need to unveil and overcome the underlying mechanisms of resistance. Activation of the transcription factor STAT3 was recently linked to CRT resistance in other gastrointestinal cancers such as rectal and esophageal cancers, but its role in PDAC needs to be clarified. Protein expression and phosphorylation of STAT3 was determined in PDAC cell lines and connected to transcriptional activity measured by dual-luciferase reporter gene assays. Inhibition of STAT3 signaling was achieved by RNAi or the small-molecule inhibitor napabucasin. We observed a positive correlation between STAT3 signaling activity and CRT resistance. Importantly, genetical and pharmacological perturbation of the IL-6/STAT3 pathway resulted in CRT sensitization specifically in those cell lines, in which STAT3 activity was augmented by IL-6. In conclusion, our data underscore the general importance of IL-6/STAT3 signaling for CRT resistance and suggest that pathway inhibition may represents a putative treatment strategy in order to increase the fraction of patients with PDAC who are candidates for surgical approaches.

Therapeutic potential of flavonoids in cancer: ROS-mediated mechanisms

Cancer is a leading cause of morbidity and mortality around the globe. Reactive oxygen species (ROS) play contradicting roles in cancer incidence and progression. Antioxidants have attracted attention as emerging therapeutic agents. Among these are flavonoids, which are natural polyphenols with established anticancer and antioxidant capacities. Increasing evidence shows that flavonoids can inhibit carcinogenesis via suppressing ROS levels. Surprisingly, flavonoids can also trigger excessive oxidative stress, but this can also induce death of malignant cells. In this review, we explore the inherent characteristics that contribute to the antioxidant capacity of flavonoids, and we dissect the scenarios in which they play the contrasting role as pro-oxidants. Furthermore, we elaborate on the pathways that link flavonoid-mediated modulation of ROS to the prevention and treatment of cancer. Special attention is given to the ROS-mediated anticancer functions that (-)-epigallocatechin gallate (EGCG), hesperetin, naringenin, quercetin, luteolin, and apigenin evoke in various cancers. We also delve into the structure-function relations that make flavonoids potent antioxidants. This review provides a detailed perspective that can be utilized in future experiments or trials that aim at utilizing flavonoids or verifying their efficacy for developing new pharmacologic agents. We support the argument that flavonoids are attractive candidates for cancer therapy.

Reactive oxygen species: Key players in the anticancer effects of apigenin?

Reactive oxygen species (ROS) exhibit a double-edged sword in cancer-hence their modulation has been an attractive strategy in cancer prevention and therapy. The abundance of scientific information on the pro-oxidant effects of apigenin in cancer cells suggests the crucial role of ROS in its mechanisms of action. Although apigenin is known to enhance the cellular ROS levels to cytotoxic degrees in cancer cells in vitro, it remains to be determined if these pro-oxidant effects prevail or are relevant in experimental tumor models and clinical trials. Here, we critically examine the pro-oxidant and antioxidant effects of apigenin in cancer to provide insightful perspectives on the association between its ROS-modulating action and anticancer potential. We also discussed these effects in a cell/tissue type-specific context to highlight the factors influencing the switch between antioxidant and pro-oxidant effects. Finally, we raised some questions that need addressing for the potential translation of these studies into clinical applications. Further research into this duality in oxidant actions of apigenin, especially in vivo, may enable better exploitation of its anticancer potential. PRACTICAL APPLICATION: Apigenin is a naturally occurring compound found in chamomile flowers, parsley, celery, peppermint, and citrus fruits. Many human trials of dietary interventions with apigenin-containing herbs and flavonoid mixture on oxidative stress markers, for instance, point to their antioxidant effects and health benefits in many diseases. Preclinical studies suggest that apigenin alone or its combination with chemotherapeutics has a strong anti-neoplastic effect and can induce ROS-mediated cytotoxicity at concentrations in the micromolar (μM) range, which may not be feasible with dietary interventions. Enhancing the in vivo pharmacokinetic properties of apigenin may be indispensable for its potential cancer-specific pro-oxidant therapy and may provide relevant information for clinical studies of apigenin either as a single agent or an adjuvant to chemotherapeutics.

Research progress of phenolic compounds regulating IL-6 to exert antitumor effects

Cytokine therapy, which activates the host immune system, has become an important and novel therapeutic approach to treat various cancers. Recent studies have shown that IL-6 is an important cytokine that regulates the homeostasis in vivo. However, excessive IL-6 plays a pathological role in a variety of acute and chronic inflammatory diseases, especially in cancer. IL-6 can transmit signals through JAK/STAT, RAS /MAPK, PI3K/ Akt, NF-κB, and other pathways to promote cancer progression. Phenolic compounds can effectively regulate the level of IL-6 in tumor cells and improve the tumor microenvironment. This article focuses on the phenolic compounds through the regulation of IL-6, participate in the prevention of cancer, inhibit the proliferation of cancer cells, reduce angiogenesis, improve therapeutic efficacy, and reduce side effects and other aspects. This will help to further advance research on cytokine therapy to reduce the burden of cancer and improve patient prognosis. However, current studies are mostly limited to animal and cellular experiments, and high-quality clinical studies are needed to further determine their antitumor efficacy in humans.

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.

Triptolide inhibits JAK2/STAT3 signaling and induces lethal autophagy through ROS generation in cisplatin‑resistant SKOV3/DDP ovarian cancer cells

Advanced and recurrent ovarian cancer has a poor prognosis and is frequently resistant to numerous therapeutics; thus, safe and effective drugs are needed to combat this disease. Previous studies have demonstrated that triptolide (TPL) exhibits anticancer and sensitization effects against cisplatin (DDP)-resistant ovarian cancer both in vitro and in vivo by inducing apoptosis; however, the involvement of autophagy induced by TPL in resistant ovarian carcinoma remains unclear. In the present study, the results revealed that TPL induced autophagy to facilitate SKOV3/DDP ovarian cancer cell death. The xenograft experiment revealed that the autophagy inhibitor CQ significantly reduced TPL-mediated chemosensitization and tumor growth inhibition. Mechanically, TPL-induced autophagy in SKOV3/DDP cells was associated with the induction of ROS generation and inhibition of the Janus kinase 2 (JAK2)/signal transducer and activator of transcription-3 (STAT3) pathway. The inhibitory effect of TPL on the JAK2/STAT3 pathway could be restored in the presence of the antioxidant NAC. Furthermore, it was further determined that TPL disrupted the interaction between Mcl-1 and Beclin1, which was prevented by the JAK2/STAT3 signaling activator IL-6. Overall, the present results revealed a novel molecular mechanism whereby TPL induced lethal autophagy through the ROS-JAK2/STAT3 signaling cascade in SKOV3/DDP cells. The present study has provided the groundwork for future application of TPL in the treatment of ovarian cancer.

The Role of Reactive Oxygen Species in Tumor Treatment and its Impact on Bone Marrow Hematopoiesis

Reactive oxygen species (ROS), an important molecule inducing oxidative stress in organisms, play a key role in tumorigenesis, tumor progression and recurrence. Recent findings on ROS have shown that ROS can be used to treat cancer as they accelerate the death of tumor cells. At present, pro-oxidant drugs that are intended to increase ROS levels of the tumor cells have been widely used in the clinic. However, ROS are a double-edged sword in the treatment of tumors. High levels of ROS induce not only the death of tumor cells but also oxidative damage to normal cells, especially bone marrow hemopoietic cells, which leads to bone marrow suppression and (or) other side effects, weak efficacy of tumor treatment and even threatening patients' life. How to enhance the killing effect of ROS on tumor cells while avoiding oxidative damage to the normal cells has become an urgent issue. This study is a review of the latest progress in the role of ROS-mediated programmed death in tumor treatment and prevention and treatment of oxidative damage in bone marrow induced by ROS.

Rationalizing the therapeutic potential of apigenin against cancer

BACKGROUND

Despite the remarkable advances made in the diagnosis and treatment of cancer during the past couple of decades, it remains the second largest cause of mortality in the world, killing approximately 9.6 million people annually. The major challenges in the treatment of the advanced stage of this disease are the development of chemoresistance, severe adverse effects of the drugs, and high treatment cost. Therefore, the development of drugs that are safe, efficacious, and cost-effective remains a 'Holy Grail' in cancer research. However, the research over the past four decades shed light on the cancer-preventive and therapeutic potential of natural products and their underlying mechanism of action. Apigenin is one such compound, which is known to be safe and has significant potential in the prevention and therapy of this disease.

AIM

To assess the literature available on the potential of apigenin and its analogs in modulating the key molecular targets leading to the prevention and treatment of different types of cancer.

METHOD

A comprehensive literature search has been carried out on PubMed for obtaining information related to the sources and analogs, chemistry and biosynthesis, physicochemical properties, biological activities, bioavailability and toxicity of apigenin.

KEY FINDINGS

The literature search resulted in many in vitro, in vivo and a few cohort studies that evidenced the effectiveness of apigenin and its analogs in modulating important molecular targets and signaling pathways such as PI3K/AKT/mTOR, JAK/STAT, NF-κB, MAPK/ERK, Wnt/β-catenin, etc., which play a crucial role in the development and progression of cancer. In addition, apigenin was also shown to inhibit chemoresistance and radioresistance and make cancer cells sensitive to these agents. Reports have further revealed the safety of the compound and the adaptation of nanotechnological approaches for improving its bioavailability.

SIGNIFICANCE

Hence, the present review recapitulates the properties of apigenin and its pharmacological activities against different types of cancer, which warrant further investigation in clinical settings.

Anticancer Effect of Salvia plebeia and Its Active Compound by Improving T-Cell Activity via Blockade of PD-1/PD-L1 Interaction in Humanized PD-1 Mouse Model

Immune checkpoint inhibitors, increasingly used to treat malignant tumors, are revolutionizing cancer treatment by improving the patient survival expectations. Despite the high antitumor efficacy of antibody therapeutics that bind to PD-1/PD-L1, study on small molecule-based PD-1/PD-L1 inhibitors is required to overcome the side effects of antibody therapeutics caused by their size and affinity. Herein, we investigated antitumor potential of Salvia plebeia R. Br. extract (SPE), which has been used as a traditional oriental medicine and food in many countries, and its components by the blockade of PD-1/PD-L1 interaction. SPE and its component cosmosiin effectively blocked the molecular interaction between PD-1 and PD-L1. SPE also inhibited tumor growth by increasing CD8+ T-cells in the tumor through the activation of tumor-specific T-cells in a humanized PD-1 mouse model bearing hPD-L1 knock-in MC38 colon adenocarcinoma tumor. This finding presents a preclinical strategy to develop small molecule-based anticancer drugs targeting the PD-1/PD-L1 immune checkpoint pathway.

Apigenin 7-O-glucoside promotes cell apoptosis through the PTEN/PI3K/AKT pathway and inhibits cell migration in cervical cancer HeLa cells

Epidemiologic evidence promote the inclusion of flavones in diet due to their inhibitory effects on certain types of cancers, particularly in women. Among the naturally occurring plant flavonoids, Apigenin 7-O-glucoside (AGL) is endowed with anti-inflammatory, anti-oxidant, and anti-cancer activities. However, its mechanism of action on cervical cancer, the fourth largest cancer in women, has not yet been clarified. In the current study, we have determined the effect of AGL on human cervical cancer cells and studied its molecular mechanism against cervical cancer. The results showed that AGL inhibited the proliferation of HeLa cells (IC₅₀ was 47.26 μM at 48 h) by inducing apoptosis. Furthermore, AGL treatment caused G0/G1 phase arrest, reduced mitochondrial membrane potential (MMP), and upgraded intracellular ROS production. AGL could promote the release of cytochrome c by regulating Bcl-2 family proteins, and then activated caspase 9/3 to promote cell apoptosis. Moreover, AGL treatment promoted the expression of p16 INK4A, while inhibited the expression of Cyclin A/D/E and CDK2/6. At the same time in HeLa cells treated with AGL, the PTEN/PI3K/AKT pathway was inhibited in a concentration-dependent manner, and cell migration was also impeded correspondingly through the matrix metalloproteinase 2 and 9. Our study may provide a new research direction for harnessing the novel natural compounds in cervical cancer treatment.

Apigetrin ameliorates streptozotocin-induced pancreatic β-cell damages via attenuating endoplasmic reticulum stress

The pathogenesis of diabetes is associated with dysfunction of pancreatic β-cells. To ameliorate the β-cell dysfunction, it has propelled great interest to search pharmacological agents from natural plants. This study explored the protective effect of apigetrin, a flavonoid present in natural plants, against streptozotocin (STZ)-induced cell damages in RINm5F cells and the potential mechanisms. Apigetrin was found to inhibit the elevation of intracellular reactive oxygen species levels, restore the impairment of antioxidant enzymes, and recover the disruption of redox homeostasis in the STZ-treated pancreatic β-cells. Moreover, treatment of apigetrin significantly suppressed the STZ-induced apoptosis in the analysis of apoptotic sub-G₁ population and the protein expressions of cleaved poly(ADP-ribose) polymerase and caspase-3. Furthermore, apigetrin attenuated STZ-induced endoplasmic reticulum (ER) stress, indicated by the reduction of ER stress biomarkers, including overloading of mitochondrial calcium, increase in glucose-regulated protein 78, phosphorylation of protein kinase RNA-like ER kinase and its downstream eukaryotic initiation factor 2α, cleavage of activating transcription factor 6 and caspase-12, up-regulation of CCAAT/enhancer binding protein homologous protein, and induction of spliced X-box binding protein 1. Additionally, pretreatment with 4-phenylbutyric acid, a classic ER stress inhibitor, augmented these beneficial effects of apigetrin. In conclusion, these results demonstrated that apigetrin could improve the STZ-induced pancreatic β-cell damages via mitigation of oxidative stress and ER stress and supported the application of apigetrin to developing the novel therapeutics of diabetes.

The lncRNA XIST promotes proliferation, migration and invasion of gastric cancer cells by targeting miR-337

BACKGROUND AND STUDY AIMS

Gastric cancer (GC) is one of the most common malignant tumours worldwide. Long non-coding RNAs (lncRNAs) and microRNAs regulate the occurrence and development of various cancers and play an important role in GC progression. X-inactive specific transcript (XIST), a carcinogenic lncRNA, is involved in human tumourigenesis and is altered in GC. Janus kinase 2 (JAK2), a transcription factor, is involved in cancer cell metastasis and differentiation. However, the exact mechanism underlying the biological roles of XIST and JAK2 in cancer cells remains unclear.

MATERIAL AND METHODS

This study was conducted using GES-1, HGC-27, AGS and HEK-293 T cells. Quantitative polymerase chain reaction and western blotting were performed to detect XIST, microRNA-337 (miR-337) and JAK2 expressions. GC cell invasion was investigated by using the Transwell assay. Fluorescein reporter gene detection was used to determine the relationship between JAK2 and XIST.

RESULTS

Compared with that in GES-1 cells, XIST expression was significantly up-regulated in AGS and HGC-27 cells. miR-337 expression in GC cell lines was decreased. The proliferation, invasion and migration of GC cells were simultaneously inhibited by XIST knockdown, and the relationship between XIST and miR-337 was confirmed by bioinformatics analysis. JAK2 is expected to be the target gene of miR-337. MiR-337 can negatively regulate JAK2 expression in vitro. In addition, si-XIST decreased JAK2 expression by up-regulating miR-337 in vitro, thereby inhibiting GC cell proliferation and migration. Therefore, we speculated that XIST regulates JAK2 by competing with miR-337 as a competitive endogenous lncRNA in GC.

CONCLUSION

We elucidated the effects of migration and invasion after XIST inhibition, at least in part, by inhibiting miR-337 expression in GC cells to regulate JAK2. These data indicate that a positive feedback loop exists between XIST and JAK2 and suggest that JAK2 and XIST play a vital role in cancer cell migration and invasion.

The preparation of a cold-water soluble polysaccharide from Grifola frondosa and its inhibitory effects on MKN-45 cells

In this study, a novel water soluble polysaccharide (named GFP-4) was extracted from Grifola frondosa at 4 ^oC, and its preliminary structure and inhibitory effects on human gastric carcinoma MKN-45 cells through the Fas/FasL death receptor apoptosis pathway were investigated. High-performance gel permeation chromatography (HPGPC), fourier-transform infrared spectroscopy (FT-IR), and ion chromatography (IC) results showed that GFP-4 was a 1.09 × 10⁶ Da neutral hetero polysaccharide with pyranose rings, and α- and β-type glycosidic linkages that contained galactose, glucose, and mannose at a molar ratio of 1.00:3.45:1.19. MTT results indicated that GFP-4 significantly inhibited the proliferation of MKN-45 cells in a concentration-dependent manner. The H&E staining and Hoechst 33342/PI double staining results showed that GFP-4-treated MKN-45 cells were subjected to underwent typical apoptotic morphologic changes such as nuclear pyknosis, chromatin condensation, and an increase of membrane permeability. Annexin V-FITC/PI double staining, cell cycle analysis, and western blot results revealed the GFP-4 induced MKN-45 cells apoptosis through the Fas/FasL-mediated death receptor pathway with cells arrested at the G0/G1 phase. These data indicate that GFP-4 is a promising candidate for treating gastric cancer and provide a theoretical basis for the future development and utilization of G. frondosa clinically.

STAT3 Pathway in Gastric Cancer: Signaling, Therapeutic Targeting and Future Prospects

Molecular signaling pathways play a significant role in the regulation of biological mechanisms, and their abnormal expression can provide the conditions for cancer development. The signal transducer and activator of transcription 3 (STAT3) is a key member of the STAT proteins and its oncogene role in cancer has been shown. STAT3 is able to promote the proliferation and invasion of cancer cells and induces chemoresistance. Different downstream targets of STAT3 have been identified in cancer and it has also been shown that microRNA (miR), long non-coding RNA (lncRNA) and other molecular pathways are able to function as upstream mediators of STAT3 in cancer. In the present review, we focus on the role and regulation of STAT3 in gastric cancer (GC). miRs and lncRNAs are considered as potential upstream mediators of STAT3 and they are able to affect STAT3 expression in exerting their oncogene or onco-suppressor role in GC cells. Anti-tumor compounds suppress the STAT3 signaling pathway to restrict the proliferation and malignant behavior of GC cells. Other molecular pathways, such as sirtuin, stathmin and so on, can act as upstream mediators of STAT3 in GC. Notably, the components of the tumor microenvironment that are capable of targeting STAT3 in GC, such as fibroblasts and macrophages, are discussed in this review. Finally, we demonstrate that STAT3 can target oncogene factors to enhance the proliferation and metastasis of GC cells.

Apigenin induces apoptosis and counteracts cisplatin-induced chemoresistance via Mcl-1 in ovarian cancer cells

Ovarian cancer (OC) is one of the prominent causes of mortality in female patients diagnosed with gynecologic malignancies. While it has previously been demonstrated that apigenin inhibits cell growth in colon and breast cancer cells, the effect of apigenin in OC cells is not fully understood. Therefore, the aim of the present study was to investigate the impact of apigenin on cell death and resistance to cisplatin in OC cells. It was found that apigenin inhibited proliferation, hindered cell cycle progression and promoted SKOV3 cell apoptosis. Moreover, these effects were also observed in cisplatin-resistant SKOV3/DDP cells. Furthermore, apigenin reduced the mitochondrial transmembrane potential, and elevated the ratios of cleaved caspase-3/caspase-3 and Bax/Bcl-2 in the two cell types. Reverse transcription-quantitative PCR and western blotting results demonstrated that apigenin significantly downregulated Mcl-1 at the transcriptional and translational levels in SKOV3 and SKOV3/DDP cells, which was responsible for its cytotoxic functions and chemosensitizing effects. Collectively, the present results identified the impact of apigenin on OC cell death and resistance to cisplatin, and the potential molecular mechanisms. However, additional studies are required to further elucidate the underlying mechanisms.

Apigetrin induces extrinsic apoptosis, autophagy and G2/M phase cell cycle arrest through PI3K/AKT/mTOR pathway in AGS human gastric cancer cell

Apigetrin is a flavonoid glycoside phytonutrient derived from fruits and vegetables that is well known for a variety of biological activities such as antioxidant and anti-inflammatory activities. In the current study, we determined the effect of apigetrin on AGS gastric cancer cell. Apigetrin reduced cancer cell proliferation and induced G2/M phase cell cycle arrest by regulating cyclin B1, cdc25c and cdk1 protein expression in AGS cell. Apigetrin treatment caused apoptotic cell death in AGS cells, characterized by the accumulation of apoptosis portion, cleavage of caspase-3 and poly ADP-ribose polymerase (PARP). Apigetrin-treated cells increased the expression of extrinsic apoptosis pathway proteins and mRNA. However, intrinsic apoptosis pathway related proteins were not altered. In addition, AGS cells treated with apigetrin increased autophagic cell death, featured by the formation of autophagic vacuole and acidic vesicular organelles. Autophagy marker proteins, such as LC3B-II and beclin-1, were increased, and p62, an autophagy flux marker protein, was also increased by endoplasmic reticulum stress. Also, the phosphorylation of PI3K/AKT/mTOR pathway proteins and its downstream targets in apigetrin-treated AGS cells was identified to be decreased. Taken together, these data suggest that apigetrin-treated AGS cells induced G2/M phase cell cycle arrest, extrinsic apoptosis and autophagic cell death through PI3K/AKT/mTOR pathway, which can lead to the inhibition of gastric cancer development. Thus, our findings strongly indicate that apigetrin is a basic natural derived compound that could be used as a nutrient source with potential anticancer activities against gastric cancer.

Glutamine affects T24 bladder cancer cell proliferation by activating STAT3 through ROS and glutaminolysis

Changes in metabolism are common phenomena in tumors. Glutamine (Gln) has been documented to play a critical role in tumor growth. In this study, we aimed to to explore the mechanisms through which bladder cancer cells utilize Gln to fulfill their biosynthetic needs during proliferation. In addition, the roles of Gln in the tricarboxylic acid (TCA) cycle, reactive oxygen species (ROS) regulation, and signal transducer and activator of transcription 3 (STAT3) expression were examined in vitro in the T24 bladder cancer cell line. The results revealed that the T24 cell line was markedly Gln-dependent and that Gln supplementation promoted T24 proliferation through the actions of Gln as a ROS moderator and as a metabolic fuel in the TCA cycle. Importantly, extracellular Gln deprivation deregulated the production of the transcription factor, STAT3. Additionally, STAT3 expression was affected by the degree of Gln metabolism, as regulated by Gln intermediates and ROS. Thus, on the whole, the findings of this study demonstrate that Gln promotes the proliferation of the Gln-dependent bladder cancer cell line, T24, by supplementing adenosine triphosphate (ATP) production and neutralizing ROS to activate the STAT3 pathway.

Topoisomerase inhibitors promote cancer cell motility via ROS-mediated activation of JAK2-STAT1-CXCL1 pathway

Background

Topoisomerase inhibitors (TI) can inhibit cell proliferation by preventing DNA replication, stimulating DNA damage and inducing cell cycle arrest. Although these agents have been commonly used in the chemotherapy for the anti-proliferative effect, their impacts on the metastasis of cancer cells remain obscure.

Methods

We used the transwell chamber assay to test effects of Topoisomerase inhibitors Etoposide (VP-16), Adriamycin (ADM) and Irinotecan (CPT-11) on the migration and invasion of cancer cells. Conditioned medium (CM) from TI-treated cells was subjected to Mass spectrometry screening. Gene silencing, neutralizing antibody, and specific chemical inhibitors were used to validate the roles of signaling molecules.

Results

Our studies disclosed that TI could promote the migration and invasion of a subset of cancer cells, which were dependent on chemokine (C-X-C motif) ligand 1 (CXCL1). Further studies disclosed that TI enhanced phosphorylation of Janus kinase 2 (JAK2) and Signal transducers and activators of transcription 1 (STAT1). Silencing or chemical inhibition of JAK2 or STAT1 abrogated TI-induced CXCL1 expression and cell motility. Moreover, TI increased cellular levels of reactive oxygen species (ROS) and promoted oxidation of Protein Tyrosine Phosphatase 1B (PTP1B), while reduced glutathione (GSH) reversed TI-induced JAK2-STAT1 activation, CXCL1 expression, and cell motility.

Conclusions

Our study demonstrates that TI can promote the expression and secretion of CXCL1 by elevating ROS, inactivating PTP1B, and activating JAK2-STAT1 signaling pathway, thereby promoting the motility of cancer cells.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1353-2) contains supplementary material, which is available to authorized users.

Cycloastragenol can negate constitutive STAT3 activation and promote paclitaxel-induced apoptosis in human gastric cancer cells

BACKGROUND

Cycloastragenol (CAG), a triterpene aglycone is commonly prescribed for treating hypertension, cardiovascular disease, diabetic nephropathy, viral hepatitis, and various inflammatory-linked diseases.

HYPOTHESIS

We investigated CAG for its action on signal transducer and activator of transcription 3 (STAT3) activation cascades, and its potential to sensitize gastric cancer cells to paclitaxel-induced apoptosis.

METHODS

The effect of CAG on STAT3 phosphorylation and other hallmarks of cancer was deciphered using diverse assays in both SNU-1 and SNU-16 cells.

RESULTS

We observed that CAG exhibited cytotoxic activity against SNU-1 and SNU-16 cells to a greater extent as compared to normal GES-1 cells. CAG predominantly caused negative regulation of STAT3 phosphorylation at tyrosine 705 through the abrogation of Src and Janus-activated kinases (JAK1/2) activation. We noted that CAG impaired translocation of STAT3 protein as well as its DNA binding activity. It further decreased cellular proliferation and mediated its anticancer effects predominantly by causing substantial apoptosis rather than autophagy. In addition, CAG potentiated paclitaxel-induced anti-oncogenic effects in gastric tumor cells.

CONCLUSIONS

Our results indicate that CAG can function to impede STAT3 activation in human gastric tumor cells and therefore it may be a suitable candidate agent for therapy of gastric cancer.

Molecular Targets of Genistein and Its Related Flavonoids to Exert Anticancer Effects

Increased health awareness among the public has highlighted the health benefits of dietary supplements including flavonoids. As flavonoids target several critical factors to exert a variety of biological effects, studies to identify their target-specific effects have been conducted. Herein, we discuss the basic structures of flavonoids and their anticancer activities in relation to the specific biological targets acted upon by these flavonoids. Flavonoids target several signaling pathways involved in apoptosis, cell cycle arrest, mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)/AKT kinase, and metastasis. Polo-like kinase 1 (PLK1) has been recognized as a valuable target in cancer treatment due to the prognostic implication of PLK1 in cancer patients and its clinical relevance between the overexpression of PLK1 and the reduced survival rates of several carcinoma patients. Recent studies suggest that several flavonoids, including genistein directly inhibit PLK1 inhibitory activity. Later, we focus on the anticancer effects of genistein through inhibition of PLK1.

Copper or Manganese Supplementation Endows the Peptic Hydrolysate from Bovine Lactoferrin with Enhanced Activity to Human Gastric Cancer AGS Cells

A lactoferrin hydrolysate (LFH) was generated from bovine lactoferrin by pepsin, mixed with Cu²⁺ and Mn²⁺ at 0.64-1.28 and 0.28-0.56 mg/g protein, respectively; and then their in vitro effects on human gastric cancer AGS cells were assessed. With incubation times of 24 or 48 h, LFH and its Cu²⁺/Mn²⁺ mixtures at 10-30 mg/mL in dose-dependent manner inhibited cell growth; and more, these mixtures showed higher activities than LFH alone. Cell treatments of LFH and the mixtures (25 mg/mL) for 24 h could arrest cell cycle at G0/G1-phase, damage mitochondrial membrane integrity, and induce apoptosis, while the mixtures were also more powerful than LFH to exert these three effects. Higher Cu²⁺/Mn²⁺ supplementation level resulted in higher growth inhibition, cell cycle arrest, mitochondrial membrane potential disruption, and apoptosis induction; furthermore, Mn²⁺ was notable for its higher efficacy than Cu²⁺ to increase these four effects. Western-blot assay results revealed that four apoptosis-related proteins Bad, Bax, cytochrome c, and p53 were up-regulated, and both caspase-3 and caspase-9 also were cleaved and activated; moreover, two autophagy-related proteins LC3-II and cleaved Beclin-1 were down- and up-regulated, respectively. It is thus concluded that Cu²⁺ and especially Mn²⁺ could endow supplemented LFH with increased anti-cancer effects in AGS cells, with two proposed events as enhanced apoptosis induction (via activating apoptosis-related proteins) and autophagy inhibition (via activating autophagy-related proteins).

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.