Autophagy: Mechanisms and Therapeutic Potential of Flavonoids in Cancer

NCX1/Ca2+ promotes autophagy and decreases bortezomib activity in multiple myeloma through non-canonical NFκB signaling pathway

Although bortezomib (BTZ) is the cornerstone of anti-multiple myeloma (MM) therapy, the inevitable primary and secondary drug resistance still seriously affects the prognosis of patients. New treatment strategies are in need. Sodium-calcium exchanger 1 (NCX1) is a calcium-permeable ion transporter on the membrane, and our previous studies showed that low NCX1 confers inferior viability in MM cells and suppressed osteoclast differentiation. However, the effect of NCX1 on BTZ sensitivity of MM and its possible mechanism remain unclear. In this study, we investigated the effect of NCX1 on BTZ sensitivity in MM, focusing on cellular processes of autophagy and cell viability. Our results provide evidence that NCX1 expression correlates with MM disease progression and low NCX1 expression increases BTZ sensitivity. NCX1/Ca2+ triggered autophagic flux through non-canonical NFκB pathway in MM cells, leading to attenuated the sensitivity of BTZ. Knockdown or inhibition of NCX1 could potentiate the anti-MM activity of BTZ in vitro and vivo, and inhibition of autophagy sensitized NCX1-overexpressing MM cells to BTZ. In general, this work implicates NCX1 as a potential therapeutic target in MM with BTZ resistance and provides novel mechanistic insights into its vital role in combating BTZ resistance.

Interaction of selected alkoxy naringenin oximes with model and bacterial membranes

Naringenin is a flavonoid found in many fruits and herbs, most notably in grapefruits. In recent years, this compound and its derivatives have been of great interest due to their high biological activity, including fungicidal and bactericidal effects, also in relation to multidrug-resistant bacteria. Membrane interactions of naringenin oxime (NO) and its 7-O-alkyl (7-alkoxy) derivatives, such as methyl (7MENO), ethyl (7ETNO), isopropyl (7IPNO), n-butyl (7BUNO) and n-pentyl (7PENO) were studied. Thermotropic properties of model membranes were investigated via differential scanning calorimetry (DSC), the influence on lipid raft mimicking giant unilamellar vesicles (GUVs) via fluorescence microscopy, and membrane permeability via measuring calcein leakage from liposomes. Molecular calculations supplemented the study. The influence of naringenin oximes on two strains of multidrug resistant bacteria: Staphylococcus aureus KJ and Enterococcus faecalis 37VRE was also investigated. In DSC studies all compounds reduced the temperature and enthalpy of main phase transition and caused disappearing of the pretransition. NO was the least active. The reduction in the area of surface domains in GUVs was observed for NO. Compounds NO and 7BUNO resulted in very low secretion of calcein from liposomes (permeability < 3 %). The highest results were observed for 7MENO (88.4 %) and 7IPNO (78.5 %). When bacterial membrane permeability was investigated all compounds caused significant release of propidium iodide from S. aureus (31.6-87.0 % for concentration 128 μg/mL). In the case of E. faecalis, 7ETNO (75.7 %) and NO (28.8 %) were the most active. The rest of the tested compounds showed less activity (permeability < 13.9 %). The strong evidence was observed that antibacterial activity of the tested compounds may be associated with their interaction with bacterial membrane.

A review of natural products and small-molecule therapeutics acting on central nervous system malignancies: Approaches for drug development, targeting pathways, clinical trials, and challenges

In 2021, the World Health Organization released the fifth edition of the central nervous system (CNS) tumor classification. This classification uses histopathology and molecular pathogenesis to group tumors into more biologically and molecularly defined entities. The prognosis of brain cancer, particularly malignant tumors, has remained poor worldwide, approximately 308,102 new cases of brain and other CNS tumors were diagnosed in the year 2020, with an estimated 251,329 deaths. The cost and time-consuming nature of studies to find new anticancer agents makes it necessary to have well-designed studies. In the present study, the pathways that can be targeted for drug development are discussed in detail. Some of the important cellular origins, signaling, and pathways involved in the efficacy of bioactive molecules against CNS tumorigenesis or progression, as well as prognosis and common approaches for treatment of different types of brain tumors, are reviewed. Moreover, different study tools, including cell lines, in vitro, in vivo, and clinical trial challenges, are discussed. In addition, in this article, natural products as one of the most important sources for finding new chemotherapeutics were reviewed and over 700 reported molecules with efficacy against CNS cancer cells are gathered and classified according to their structure. Based on the clinical trials that have been registered, very few of these natural or semi-synthetic derivatives have been studied in humans. The review can help researchers understand the involved mechanisms and design new goal-oriented studies for drug development against CNS malignancies.

Flavonoids with Anti-Angiogenesis Function in Cancer

The formation of new blood vessels, known as angiogenesis, significantly impacts the development of multiple types of cancer. Consequently, researchers have focused on targeting this process to prevent and treat numerous disorders. However, most existing anti-angiogenic treatments rely on synthetic compounds and humanized monoclonal antibodies, often expensive or toxic, restricting patient access to these therapies. Hence, the pursuit of discovering new, affordable, less toxic, and efficient anti-angiogenic compounds is imperative. Numerous studies propose that natural plant-derived products exhibit these sought-after characteristics. The objective of this review is to delve into the anti-angiogenic properties exhibited by naturally derived flavonoids from plants, along with their underlying molecular mechanisms of action. Additionally, we summarize the structure, classification, and the relationship between flavonoids with their signaling pathways in plants as anti-angiogenic agents, including main HIF-1α/VEGF/VEGFR2/PI3K/AKT, Wnt/β-catenin, JNK1/STAT3, and MAPK/AP-1 pathways. Nonetheless, further research and innovative approaches are required to enhance their bioavailability for clinical application.

Chemotherapeutic effect of baicalein/epirubicin combination against liver cell carcinoma in-vitro: Inducing apoptosis and autophagy

Flavonoids have a pivotal cytotoxic effect against hepatocellular carcinoma (HCC). The current study aimed to investigate which flavonoid isolated from Physalis pubescens L. leaves has the most cytotoxic effect against Hep-G2 liver cancer cells and if it could ameliorate epirubicin efficacy and safety. Baicalein trimethyl ether (BTME), rutin, quercitrin and myricitrin were isolated from Physalis Pubescens L. leaves. Hep-G2 cells were treated with the isolated flavonoids as well as a combination of BTME and epirubicin. Cell viability and the chromosomal DNA fragmentation in Hep-G2 cells were assessed. BTME showed the best cytotoxic effect against Hep-G2 cells. Combination of epirubicin with (200 μg/mL) BTME significantly decreased the IC50 of epirubicin from 2.79 ± 0.626 μg/mL to 0.76 ± 0.258 μg/mL. Moreover, the same combination significantly increased the IC50 of BTME against WI-38 normal cells. DNA fragmentation as well as the concentration of beclin 1 and Bax were significantly increased in Hep-G2 cells treated with BTME and BTME+epirubicin compared to untreated cells. Besides, BTME and BTME+epirubicin significantly decreased the gene expression of TGFβ1 whereas increased ATG-7 gene expression. Conclusions: BTME (200μg/mL) significantly enhanced epirubicin's cytotoxicity against Hep-G2 cells and ameliorated its safety profile. BTME could exert anti-hepatocarcinoma effect by enhancing apoptosis and autophagy.

Natural Activators of Autophagy

Autophagy is the process by which cell contents, such as aggregated proteins, dysfunctional organelles, and cell structures are sequestered by autophagosome and delivered to lysosomes for degradation. As a process that allows the cell to get rid of non-functional components that tend to accumulate with age, autophagy has been associated with many human diseases. In this regard, the search for autophagy activators and the study of their mechanism of action is an important task for treatment of many diseases, as well as for increasing healthy life expectancy. Plants are rich sources of autophagy activators, containing large amounts of polyphenolic compounds in their composition, which can be autophagy activators in their original form, or can be metabolized by the intestinal microbiota to active compounds. This review is devoted to the plant-based autophagy activators with emphasis on the sources of their production, mechanism of action, and application in various diseases. The review also describes companies commercializing natural autophagy activators.

Flavonoids as promising molecules in the cancer therapy: An insight

Cancer continues to increase global morbidity and mortality rates. Despite substantial progress in the development of various chemically synthesized anti-cancer drugs, the poor prognosis of the disease still remains a big challenge. The most common drawback of conventional cancer therapies is the emergence of drug resistance eventually leading to the discontinuation of chemotherapy. Moreover, advanced target-specific therapies including immunotherapy and stem cell therapy are expensive enough and are unaffordable for most patients in poorer nations. Therefore, alternative and cheaper therapeutic strategies are needed to complement the current cancer treatment approaches. Phytochemicals are bioactive compounds produced naturally by plants and have great potential in human health and disease. These compounds possess antiproliferative, anti-oxidant, and immunomodulatory properties. Among the phytochemicals, flavonoids are very effective in treating a wide range of diseases from cardiovascular diseases and immunological disorders to cancer. They scavenge reactive oxygen species (ROS), inhibit cancer metastasis, modulate the immune system and induce apoptotic or autophagic cell death in cancers. This review will discuss the potential of various phytochemicals particularly flavonoids in attempts to target various cancers.

DNA hypomethylation by fisetin preserves mitochondria functional genes and contributes to the protection of I/R rat heart

Myocardial I/R can alter the expression of different sets of cardiac genes that negatively influence the I/R outcome via epigenetic modifications. Fisetin is known to be cardioprotective against I/R, but its underlying epigenetic mode of action is not known and is addressed in the present study. Male Wistar rats were subjected to I/R by using the Langendorff perfusion system. Fisetin (20 mg/kg; i.p.) was administered before I/R induction, followed by the measurement of cardiac injury, hemodynamics, physiological indices, the differential expression of genes that regulate DNA methylation, and the function of mitochondria were performed. Fisetin administered I/R rat heart significantly reduced the global DNA hypermethylation and infarct size with an improved physiological recovery, measured via RPP (81%) and LVDP (82%) from the I/R control. Additionally, we noted decreased expression of the DNMT1 gene by 35% and increased expression of the TET1, TET2, and TET3 genes in fisetin-treated I/R rat hearts. Molecular docking analysis data reveals that the fisetin inhibits DNMT1 at the substrate binding site with minimum binding energy (- 8.2 kcal/mol) compared to the DNMT1 inhibitor, 5-azacytidine. Moreover, fisetin-treated I/R heart reversed the expression of the I/R-linked declined expression of bioenergetics genes (MT-ND1, MT-ND2, MT-ND4, MT-Cyt B, MT-COX1, MT-COX2, MT-ATP6), mitochondrial fission gene (Fis1), replication control genes PGC-1α, POLG, and TFAM to near-normal level. Based on the above findings, we demonstrated that fisetin possesses the ability to modulate the expression of different mitochondrial genes via influencing the global DNA methylation in cardiac tissue, which contributes significantly to the improved contractile function and thereby renders cardioprotection against I/R.

Sakuranin represses the malignant biological behaviors of human bladder cancer cells by triggering autophagy via activating the p53/mTOR pathway

OBJECTIVE

Sakura extract is a natural flavonoid compound that may have potential anti-tumor effects. The paper focuses on investigating Sakuranin mechanism on bladder cancer (BC) cells.

METHODS

BC cells (T24) were treated with different concentrations of Sakuranin, with 48-h IC50 determined. T24 cells were treated with Sakuranin at IC50, followed by assessment of cell proliferative/apoptotic/migrative/invasive activities by CCK-8, EdU and plate clone formation assays/flow cytometry/Transwell/scratch test. MMP-2 (migration and invasion-related protein) protein level was assessed by Western blot. Cell autophagy was evaluated by measuring the protein levels of autophagy markers (LC3-I/LC3-II/p62) through Western blot. The autophagy inhibitor 3-MA was used to validate the role of autophagy in the regulatory mechanism of Sakuranin in T24 cell behaviors. Furthermore, the activation of the p53/mTOR pathway in cells was detected and a combination of Sakuranin and p53 inhibitor Pifithrin-µ was adopted to explore the involvement of this pathway.

RESULTS

Sakuranin decreased T24 cell proliferation/EdU positive cell percentage/colony formation number and area/migration/invasion/scratch healing/MMP-2 protein level, and accelerated apoptosis. Sakuranin elevated the LC3-II/I ratio and lowered p62 level in T24 cells. 3-MA partially averted Sakuranin-mediated repression on cell malignant behaviors. Sakuranin upregulated p-p53 and p53 levels, and decreased the p-mTOR/mTOR ratio in T24 cells. The effects of Sakuranin on cell biological behaviors were partly annulled by Pifithrin-µ treatment.

CONCLUSION

Sakuranin suppressed T24 cell proliferation/migration/invasion, and enhanced apoptosis by potentiating autophagy through activating the p53/mTOR pathway. This study provided a theoretical basis for Sakuranin as a potential drug for clinical treatment of BC.

Flavonoids as promising anticancer agents: an in silico investigation of ADMET, binding affinity by molecular docking and molecular dynamics simulations

Cancer is one of the most concerning diseases to humankind. Various treatment strategies are being employed for its treatment, out of which use of natural products is an essential one. Flavonoids have proven to be promising anticancer targets since decades. Also, tubulin is a significant biological target for the development of anticancer agents due to its crucial role in mitosis and abundance throughout the body. In the current study, in silico ADMET parameters of 104 flavonoids were examined, followed by molecular docking with the colchicine binding site of Tubulin protein (PDB; Id 4O2B). The best conformation from each flavonoid subcategory with the best docking score (MolDock score) was further subjected to 100 ns of molecular dynamics to investigate the protein-ligand complex's stability. Different parameters such as RMSD, RMSF, rGy and SASA were calculated for the six flavonoids using molecular dynamic studies. The top most compound from all the six subcategories of flavonoids elicited best behavior in the colchicine binding site of Tubulin protein. This in silico study employing molecular docking and molecular dynamics simulation provides strong evidence for flavonoids to be excellent anti-tubulin agents for the treatment of cancer.Communicated by Ramaswamy H. Sarma.

Khalas date flavonoids inhibited cell viability, induced apoptosis and expression of the pro-autophagy LC3-B gene in human hepatocellular carcinoma cells (HepG2)

Autophagy is a protective mechanism important in human diseases as cancer. We evaluated the impact of khalas date extract (KDE) (20-60 mg/mL) on cell viability, morphological changes, DNA fragmentation and gene expression of LC3B-II associated with autophagosome on HepG2 cell line. The GC/MS identification of KDE showed its high content of flavonoids including quercetin, myricetin, kaempferol and catechol. KDE reduced cell viability of HepG2 with IC50 (31.52 mg/mL). Cells treated with KDE showed two band of DNA fragments at (30 and 40 mg) indicating that KDE induced DNA damage and apoptosis in HepG2. The analysis RT-PCR data showed a 0.2-fold increase in the expression of LC3-B in the cells treated with KDE versus control. We concluded that, KDE flavonoids such as quercetin, myricetin kaempferol exhibited anticancer properties manifested by inhibition of HepG2 cell viability and induction of apoptosis and upregulation of the pro-autophagy LC3-B gene.

Galangin mitigates glucocorticoid-induced osteoporosis by activating autophagy of BMSCs via triggering the PKA/CREB signaling pathway

Glucocorticoid-induced osteoporosis (GIOP), one of the most common and serious adverse effects associated with glucocorticoid administration, manifests as decreased bone formation and increased bone resorption, eventually culminating in bone loss. Galangin (GAL) is a flavonoid extracted from the medicinal herbal galangal that possesses a variety of pharmacological activities and can inhibit osteoclastogenesis. However, the effects of GAL on GIOP remain unclear. Our study aims to explore the effects of GAL on GIOP in mice and the underlying mechanism. Our results show that GAL markedly mitigates the severity of dexamethasone (Dex)-induced osteoporosis in mice and potentiates osteogenic differentiation in mouse bone marrow-derived mesenchymal stem cells (BMSCs). Furthermore, GAL also significantly counteracts Dex-mediated suppression of osteogenic differentiation and autophagy in human BMSCs. GAL augments PKA/CREB-mediated autophagic flux in BMSCs and the bones of osteoporotic mice. GAL-mediated osteogenic differentiation in Dex-treated BMSCs is significantly decreased by the PKA inhibitor H89 and autophagy inhibitor 3-methyladenine. Collectively, our data indicate that GAL can ameliorate GIOP, partly by augmenting the mineralization of BMSCs by potentiating PKA/CREB-mediated autophagic flux, highlighting its potential therapeutic use in treating glucocorticoid-related osteoporosis.

The Janus-Faced Role of Lipid Droplets in Aging: Insights from the Cellular Perspective

It is widely accepted that nine hallmarks-including mitochondrial dysfunction, epigenetic alterations, and loss of proteostasis-exist that describe the cellular aging process. Adding to this, a well-described cell organelle in the metabolic context, namely, lipid droplets, also accumulates with increasing age, which can be regarded as a further aging-associated process. Independently of their essential role as fat stores, lipid droplets are also able to control cell integrity by mitigating lipotoxic and proteotoxic insults. As we will show in this review, numerous longevity interventions (such as mTOR inhibition) also lead to strong accumulation of lipid droplets in Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and mammalian cells, just to name a few examples. In mammals, due to the variety of different cell types and tissues, the role of lipid droplets during the aging process is much more complex. Using selected diseases associated with aging, such as Alzheimer's disease, Parkinson's disease, type II diabetes, and cardiovascular disease, we show that lipid droplets are "Janus"-faced. In an early phase of the disease, lipid droplets mitigate the toxicity of lipid peroxidation and protein aggregates, but in a later phase of the disease, a strong accumulation of lipid droplets can cause problems for cells and tissues.

Senolytic Flavonoids Enhance Type-I and Type-II Cell Death in Human Radioresistant Colon Cancer Cells through AMPK/MAPK Pathway

Resistance to cancer therapies remains a clinical challenge and an unsolved problem. In a previous study, we characterized a new colon cancer cell line, namely HT500, derived from human HT29 cells and resistant to clinically relevant levels of ionizing radiation (IR). Here, we explored the effects of two natural flavonoids, quercetin (Q) and fisetin (F), well-known senolytic agents that inhibit genotoxic stress by selectively removing senescent cells. We hypothesized that the biochemical mechanisms responsible for the radiosensitising effects of these natural senolytics could intercept multiple biochemical pathways of signal transduction correlated to cell death resistance. Radioresistant HT500 cells modulate autophagic flux differently than HT29 cells and secrete pro-inflammatory cytokines (IL-8), commonly associated with senescence-related secretory phenotypes (SASP). Q and F inhibit PI₃K/AKT and ERK pathways, which promote p16^INK4 stability and resistance to apoptosis, but they also activate AMPK and ULK kinases in response to autophagic stress at an early stage. In summary, the combination of natural senolytics and IR activates two forms of cell death: apoptosis correlated to the inhibition of ERKs and lethal autophagy dependent on AMPK kinase. Our study confirms that senescence and autophagy partially overlap, share common modulatory pathways, and reveal how senolytic flavonoids can play an important role in these processes.

Marein reduces lipid levels via modulating the PI3K/AKT/mTOR pathway to induce lipophagy

ETHNOPHARMACOLOGICAL RELEVANCE

The capitulum of Coreopsis tinctoria Nutt. (CT, Xue-Ju in Chinese) is a precious medicine in Xinjiang Uygur Autonomous region of China. The Coreopsis tinctoria Nutt. is used to prevent and treat dyslipidemia, coronary heart disease, etc. Recent studies have shown that its extract has a pharmacological effect on hyperlipidemia and hyperglycemia.

AIM OF THE STUDY

The study aimed to systematically evaluate the lipid-lowering activity of CT through a mice model of hyperlipidemia and a human hepatoma G2 (HepG2) cells model of lipid accumulation, and to investigate its main active components and mechanism.

MATERIALS AND METHODS

Biochemical analysis of blood/liver lipids and liver histopathology were used to evaluate the effect of the aqueous extract of Coreopsis tinctoria Nutt. (AECT) on hyperlipidemia mice. High-performance liquid chromatography (HPLC) analysis was used to identify the main components in the AECT. Oil red O staining, immunofluorescence, western blotting, and determination of the total cholesterol (TC), total triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were used to further study the effect and potential mechanism of the AECT main components on sodium oleate-induced lipid accumulation in HepG2 cells.

RESULTS

We confirmed the lipid-lowering activity of the aqueous extract and further identified flavonoids as its main components. Among them, five Coreopsis tinctoria Nutt. flavonoids mixture (FM) significantly reduced lipid droplet area, lipid content, TC, TG, and LDL-C levels, and elevated HDL-C levels in HepG2 cells induced by sodium oleate. Furthermore, they increased lipophagy in HepG2 lipid-accumulating cells, while decreasing the ratio of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR. Most importantly, marein may be a key component.

CONCLUSIONS

Our study demonstrated that AECT, with flavonoids as the main component, can improve diet-induced hyperlipidemia in obese mice. Among the main five flavonoids, marein plays a key role in promoting lipophagy by regulating the PI3K/AKT/mTOR pathway, resulting in a lipid-lowering effect.

Phytochemicals in Cancer Treatment and Cancer Prevention-Review on Epidemiological Data and Clinical Trials

Phytochemicals are a non-nutritive substances that are present in plants and contribute significantly to their flavor and color. These biologically active compounds are classified into five major groups, namely phenolics, carotenoids, organosulfur compounds, nitrogen-containing compounds, and alkaloids, and are known for their potential health benefits in the prevention of various diseases, including cancer. The purpose of this review article is to explore the potential therapeutic benefits of the dietary phytochemicals, such as flavonoids, phenolic acids, phytosterols, carotenoids, and stilbenes, in cancer treatment and prevention based on the epidemiological studies and clinical trials. Although the majority of epidemiological studies report a significant advantage of the heightened phytochemical consumption and increased serum levels of these compounds, linking increased exposure with a lower cancer risk across most cancer types, these effects could not be replicated in the most available clinical trials. In fact, many of these trials were withdrawn early due to a lack of evidence and/or risk of harm. Despite the strong anticancer effect of phytochemicals, as well as their proven efficacy in multiple epidemiological studies, there is still a great need for human studies and clinical trials, with great caution regarding the safety measures. This review article provides an overview of the epidemiological and clinical evidence supporting the potential chemopreventive and anticancer properties of phytochemicals, with a focus on the need for further research in this area.

Therapeutic Properties of Flavonoids in Treatment of Cancer through Autophagic Modulation: A Systematic Review

Cancers have high morbidity and mortality rates worldwide. Current anticancer therapies have demonstrated specific signaling pathways as a target in the involvement of carcinogenesis. Autophagy is a quality control system for proteins and plays a fundamental role in cancer carcinogenesis, exerting an anticarcinogenic role in normal cells and can inhibit the transformation of malignant cells. Therefore, drugs aimed at autophagy can function as antitumor agents. Flavonoids are a class of polyphenolic secondary metabolites commonly found in plants and, consequently, consumed in diets. In this review, the systematic search strategy was used, which included the search for descriptors "flavonoids" AND "mTOR pathway" AND "cancer" AND "autophagy", in the electronic databases of PubMed, Cochrane Library, Web of Science and Scopus, from January 2011 to January 2021. The current literature demonstrates that flavonoids have anticarcinogenic properties, including inhibition of cell proliferation, induction of apoptosis, autophagy, necrosis, cell cycle arrest, senescence, impaired cell migration, invasion, tumor angiogenesis and reduced resistance to multiple drugs in tumor cells. We demonstrate the available evidence on the roles of flavonoids and autophagy in cancer progression and inhibition. (Registration No. CRD42021243071 at PROSPERO).

Recent Advances in Cellular Signaling Interplay between Redox Metabolism and Autophagy Modulation in Cancer: An Overview of Molecular Mechanisms and Therapeutic Interventions

Autophagy is a fundamental homeostatic process in which certain cellular components are ingested by double-membrane autophagosomes and then degraded to create energy or to maintain cellular homeostasis and survival. It is typically observed in nutrient-deprived cells as a survival mechanism. However, it has also been identified as a crucial process in maintaining cellular homeostasis and disease progression. Normal cellular metabolism produces reactive oxygen (ROS) and nitrogen species at low levels. However, increased production causes oxidative stress, which can lead to diabetes, cardiovascular diseases, neurological disorders, and cancer. It was recently shown that maintaining redox equilibrium via autophagy is critical for cellular responses to oxidative stress. However, little is understood about the molecular cancer processes that connect to the control of autophagy. In cancer cells, oncogenic mutations, carcinogens, and metabolic reprogramming cause increased ROS generation and oxidative stress. Recent studies have suggested that increased ROS generation activates survival pathways that promote cancer development and metastasis. Moreover, the relationship between metabolic programming and ROS in cancer cells is involved in redox homeostasis and the malignant phenotype. Currently, while the signaling events governing autophagy and how redox homeostasis affects signaling cascades are well understood, very little is known about molecular events related to autophagy. In this review, we focus on current knowledge about autophagy modulation and the role of redox metabolism to further the knowledge of oxidative stress and disease progression in cancer regulation. Therefore, this review focuses on understanding how oxidation/reduction events fine-tune autophagy to help understand how oxidative stress and autophagy govern cancer, either as processes leading to cell death or as survival strategies for maintaining redox homeostasis in cancer.

Recent advances in flavonoid-based nanocarriers as an emerging drug delivery approach for cancer chemotherapy

Flavonoids are an interesting class of biomolecules, which exhibit cancer-inhibitory effects through both chemopreventive and chemotherapeutic activities. However, their therapeutic efficacy is affected by poor pharmacokinetics (PK) and biopharmaceutical attributes. One of the most promising approaches to resolve these issues is to formulate flavonoids in nanosystems. Different flavonoid nanoformulations have shown therapeutic superiority over free flavonoids. Functionalization of nanoparticles (NPs) further improves their therapeutic efficacy by facilitating site-specific delivery and reducing nonspecific toxicities. In this review, we highlight recent developments in the field of flavonoid-based NPs to gain translational insights into the potential applications of flavonoid-based nanocarriers in cancer management.

Metabolomic responses to the mechanical wounding of Catharanthus roseus' upper leaves

Purpose

Plant secondary metabolites are used to treat various human diseases. However, it is difficult to produce a large number of specific metabolites, which largely limits their medicinal applications. Many methods, such as drought and nutrient application, have been used to induce the biosynthetic production of secondary metabolites. Among these secondary metabolite-inducing methods, mechanical wounding maintains the composition of secondary metabolites with little potential risk. However, the effects of mechanical stress have not been fully investigated, and thus this method remains widely unused.

Methods

In this study, we used metabolomics to investigate the metabolites produced in the upper and lower leaves of Catharanthus roseus in response to mechanical wounding.

Results

In the upper leaves, 13 different secondary metabolites (three terpenoid indole alkaloids and 10 phenolic compounds) were screened using an orthogonal partial least squares discriminant analysis (OPLS-DA) score plot. The mechanical wounding of different plant parts affected the production of secondary metabolites. Specifically, when lower leaves were mechanically wounded, the upper leaves became a strong source of resources. Conversely, when upper leaves were injured, the upper leaves themselves became a resource sink. Changes in the source-sink relationship reflected a new balance between resource tradeoff and the upregulation or downregulation of certain metabolic pathways.

Conclusion

Our findings suggest that mechanical wounding to specific plant parts is a novel approach to increase the biosynthetic production of specific secondary metabolites. These results indicate the need for a reevaluation of production practices for secondary metabolites from select commercial plants.

Induction of autophagy via the PI3K/Akt/mTOR signaling pathway by Pueraria flavonoids improves non-alcoholic fatty liver disease in obese mice

Non-alcoholic fatty liver disease (NAFLD) is the most common among lipid metabolism disorders. Autophagy plays an important role in lipid metabolism in NAFLD. Pueraria flavonoids, the main active ingredients of Pueraria lobata, exert antioxidant and anti-inflammatory effects. Herein, we report the potential lipid-lowering and anti-inflammatory effects of Pueraria flavonoids on NAFLD induced by a high-fat diet. In vivo and in vitro experiments showed that Pueraria flavonoids reduced intracellular lipid deposition by inhibiting lipid synthesis and the release of pro-inflammatory cytokines. We analyzed the autophagy flux by mRFP-GFP-LC3 plasmid transfection to assess the role of autophagy in intracellular scavenging. After treating mice fed on high fat and HepG2 cells with Pueraria flavonoids, the number of autophagosomes increased significantly, along with the level of autophagy. The autophagy loss after siRNA transfection aggravated lipid deposition and the release of inflammatory cytokines. Mechanistically, Pueraria flavonoids trigger autophagy through PI3K/Akt/mTOR signaling pathway to reduce lipid deposition and inflammation. In summary, our results showed that Pueraria flavonoids stimulated autophagy by inhibiting the PI3K/Akt/mTOR signaling pathway, thereby reducing intracellular lipid accumulation and inflammation levels and alleviating NAFLD.

Anti-cancer properties of cannflavin A and potential synergistic effects with gemcitabine, cisplatin, and cannabinoids in bladder cancer

Introduction

Several studies have shown anti-tumor effects of components present in cannabis in different models. Unfortunately, little is known about the potential anti-tumoral effects of most compounds present in cannabis in bladder cancer and how these compounds could potentially positively or negatively impact the actions of chemotherapeutic agents. Our study aims to evaluate the effects of a compound found in Cannabis sativa that has not been extensively studied to date, cannflavin A, in bladder cancer cell lines. We aimed to identify whether cannflavin A co-treatment with agents commonly used to treat bladder cancer, such as gemcitabine and cisplatin, is able to produce synergistic effects. We also evaluated whether co-treatment of cannflavin A with various cannabinoids could produce synergistic effects.

Methods

Two transitional cell carcinoma cell lines were used to assess the cytotoxic effects of the flavonoid cannflavin A up to 100 μM. We tested the potential synergistic cytotoxic effects of cannflavin A with gemcitabine (up to 100 nM), cisplatin (up to 100 μM), and cannabinoids (up to 10 μM). We also evaluated the activation of the apoptotic cascade using annexin V and whether cannflavin A has the ability to reduce invasion using a Matrigel assay.

Results

Cell viability of bladder cancer cell lines was affected in a concentration-dependent fashion in response to cannflavin A, and its combination with gemcitabine or cisplatin induced differential responses—from antagonistic to additive—and synergism was also observed in some instances, depending on the concentrations and drugs used. Cannflavin A also activated apoptosis via caspase 3 cleavage and was able to reduce invasion by 50%. Interestingly, cannflavin A displayed synergistic properties with other cannabinoids like Δ⁹-tetrahydrocannabinol, cannabidiol, cannabichromene, and cannabivarin in the bladder cancer cell lines.

Discussion

Our results indicate that compounds from Cannabis sativa other than cannabinoids, like the flavonoid cannflavin A, can be cytotoxic to human bladder transitional carcinoma cells and that this compound can exert synergistic effects when combined with other agents. In vivo studies will be needed to confirm the activity of cannflavin A as a potential agent for bladder cancer treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42238-022-00151-y.

Citri Reticulatae Pericarpium (Chenpi): A multi-efficacy pericarp in treating cardiovascular diseases

Citri Reticulatae Pericarpium (CRP) has been utilized as a versatile medicinal herb with wide cardiovascular benefits in Asian nations for centuries. Accumulating evidence suggests that CRP and its components are effective in preventing cardiovascular diseases (CVDs) such as atherosclerosis, myocardial infarction, myocardial ischemia, arrhythmia, cardiac hypertrophy, heart failure, and hypertension. Studies show that the two most bioactive components of CRP are flavonoids and volatile oils. The cardiovascular protective effects of CRP have attracted considerable research interest due to its hypolipidemic, antiplatelet activity, antioxidant and anti-inflammatory effects. Hereby, we provide a rigorous and up-to-date overview of the cardiovascular protective properties and the potential molecular targets of CRP, and finally highlight the pharmacokinetics and the therapeutic potential of the main pharmacologically active components of CRP to treat CVDs.

Naringin and Naringenin: Their Mechanisms of Action and the Potential Anticancer Activities

Naringin and naringenin are the main bioactive polyphenols in citrus fruits, the consumption of which is beneficial for human health and has been practiced since ancient times. Numerous studies have reported these substances’ antioxidant and antiandrogenic properties, as well as their ability to protect from inflammation and cancer, in various in vitro and in vivo experimental models in animals and humans. Naringin and naringenin can suppress cancer development in various body parts, alleviating the conditions of cancer patients by acting as effective alternative supplementary remedies. Their anticancer activities are pleiotropic, and they can modulate different cellular signaling pathways, suppress cytokine and growth factor production and arrest the cell cycle. In this narrative review, we discuss the effects of naringin and naringenin on inflammation, apoptosis, proliferation, angiogenesis, metastasis and invasion processes and their potential to become innovative and safe anticancer drugs.

Inhibition of NLRP3 by Fermented Quercetin Decreases Resistin-Induced Chemoresistance to 5-Fluorouracil in Human Colorectal Cancer Cells

The drug resistance of colorectal cancer (CRC) cells against 5-fluorouracil (5-FU) therapy is a major challenge to successful cancer treatment. While previous studies have proposed several 5-FU resistance mechanisms, the effects of the adipokines on cancer cells remain unclear. Thus, this study investigated the effect of resistin on 5-FU-treated CRC cell lines. The upregulation of NLRP3 can regulate the inflammatory responses in cancer cells and then enhance cancer progression. This study investigated the expression level and the function of NLRP3 on 5-FU-induced cytotoxicity in CRC cells and found that resistin-induced ERK activation and increased NLRP3 expression in CRC HCT-116 and DLD-1 cells were mediated by Toll-like receptor 4 (TLR4). The inhibition of TLR4 and ERK by pharmacological inhibitors attenuated the resistin-induced NLRP3 mRNA and protein levels. In contrast, the knockdown of NLRP3 enhanced the cytotoxic effects of 5-FU. Furthermore, quercetin is an effective chemopreventive compound. This study showed that quercetin fermented by Lactobacillus could exhibit low cytotoxicity on normal mucosa cells and improve the function of inhibiting CRC cells. The treatment of CRC cells with fermented quercetin increased the cytotoxicity and enhanced cell death in the presence of resistin. In this study, fermented quercetin induced the cytotoxicity and cell death of 5-FU in resistin-treated CRC cells, which is associated with the downregulation of NLRP3 expression and ERK phosphorylation. These results indicate the role of NLRP3 in the development of drug resistance to 5-FU in CRC cells. Elucidating the mechanism regarding the cytotoxicity effect of quercetin may provide another vision for the development of a chemotherapy strategy for CRC in the future.

Role of Intracellular Amyloid β as Pathway Modulator, Biomarker, and Therapy Target

The β- and γ-secretase-driven cleavage of the amyloid precursor protein (APP) gives rise to the amyloid β peptide, which is believed to be the main driver of neurodegeneration in Alzheimer’s disease (AD). As it is prominently detectable in extracellular plaques in post-mortem AD brain samples, research in recent decades focused on the pathological role of extracellular amyloid β aggregation, widely neglecting the potential meaning of very early generation of amyloid β inside the cell. In the last few years, the importance of intracellular amyloid β (iAβ) as a strong player in neurodegeneration has been indicated by a rising number of studies. In this review, iAβ is highlighted as a crucial APP cleavage fragment, able to manipulate intracellular pathways and foster neurodegeneration. We demonstrate its relevance as a pathological marker and shed light on initial studies aiming to modulate iAβ through pharmacological treatment, which has been shown to have beneficial effects on cognitive properties in animal models. Finally, we display the relevance of viral infections on iAβ generation and point out future directions urgently needed to manifest the potential relevance of iAβ in Alzheimer’s disease.

A comprehensive and current review on the role of flavonoids in lung cancer-Experimental and theoretical approaches

BACKGROUND

It is well-known that flavonoids, which can be easily obtained from many fruits and vegetables are widely preferred in the treatment of some important diseases. Some researchers noted that these chemical compounds exhibit high inhibition effect against various cancer types. Many experimental studies proving this ability of the flavonoids with high antioxidant activity are available in the literature.

PUROPOSE

The main aim of this review is to summarize comprehensively anticancer properties of flavonoids against the lung cancer in the light of experimental studies and well-known theory and electronic structure principles. In this review article, more detailed and current information about the using of flavonoids in the treatment of lung cancer is presented considering theoretical and experimental approaches.

STUDY DESIGN

In addition to experimental studies including the anticancer effects of flavonoids, we emphasized the requirement of the well-known electronic structure principle in the development of anticancer drugs. For this aim, Conceptual Density Functional Theory should be considered as a powerful tool. Searching the databases including ScienceDirect, PubMed and Web of Science, the suitable reference papers for this project were selected.

METHODS

Theoretical tools like DFT and Molecular Docking provides important clues about anticancer behavior and drug properties of molecular systems. Conceptual Density Functional Theory and CDFT based electronic structure principles and rules like Hard and Soft Acid-Base Principle (HSAB), Maximum Hardness Principle, Minimum Polarizability, Minimum Electrophilicity Principles and Maximum Composite Hardness Rule introduced by one of the authors of this review are so useful to predict the mechanisms and powers of chemical systems. Especially, it cannot be ignored the success of HSAB Principle in the explanations and highlighting of biochemical interactions.

RESULTS

Both theoretical analysis and experimental studies confirmed that flavonoids have higher inhibition effect against lung cancer. In addition to many superior properties like anticancer activity, antimicrobial activity, antioxidant activity, antidiabetic effect of flavonoids, their toxicities are also explained with the help of published popular papers. Action modes of the mentioned compounds are given in detail.

CONCLUSION

The review includes detailed information about the mentioned electronic structure principles and rules and their applications in the cancer research. In addition, the epidemiology and types of lung cancer anticancer activity of flavonoids in lung cancer are explained in details.

Study on the molecular mechanism of nightshade in the treatment of colon cancer

The present study attempts to explore the effective components, action targets, and potential mechanism of nightshade for colon cancer treatment. The relationship network diagram of 'traditional Chinese medicine - component - target - disease' was firstly constructed by employing network pharmacology. Experiments were conducted in vivo and in vitro to verify the influence of quercetin, the core effective component of nightshade, on colon cancer. Meanwhile, the regulatory effects of quercetin on core targets and main signaling pathways were determined. Based on the network diagram of 'traditional Chinese medicine - component - target - disease' and KEGG analysis, quercetin might exhibit certain effects on colon cancer treatment by regulating the biological behavior of core targets related to cell apoptosis in tumors including PIK3R1, PIK3CA, Akt1, and Akt2. Furthermore, quercetin has been demonstrated in vitro experiments to suppress the proliferation and migration of colon cancer cells whereas promote their apoptosis in a dose-dependent fashion. In vivo experiments indicate that quercetin had an antitumor effect on human colon cancer SW480 cells in nude mice bearing tumors. Furthermore, PIK3CA could bind to quercetin directly, which is validated by immunocoprecipitation. Therefore, the activation of PI3K/AKT phosphorylation was inhibited by quercetin and moreover the expressions of apoptotic proteins caspase-3 and Bcl2-Associated X protein (BAX) were up-regulated. In conclusion, the potential mechanism of nightshade lies in the activation of the PI3K/AKT signaling pathway inhibited by quercetin, thus promoting apoptosis of colon cancer cells for colon cancer treatment.

Radical cyclization of alkynyl aryl ketones for the synthesis of 3-seleno-substituted thiochromones and chromones

Herein we present an alternative and transition-metal-free procedure to access 3-organoselanylthiochromones and 3-organoselanylchromones from the cyclization reaction between alkynyl aryl ketones and diorganyl diselenides promoted by Oxone®.

Shikonin Induced Program Cell Death through Generation of Reactive Oxygen Species in Renal Cancer Cells

Shikonin mitigated tumor cell proliferation by elevating reactive oxygen species (ROS) levels. Herein, we investigated the effects of shikonin on renal cancer cell (RCC) cell proliferation. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that shikonin dose-dependently reduced the proliferation of Caki-1 and ACHN cells. Shikonin remarkably triggered necrosis and apoptosis in Caki-1 and ACHN cells in proportion to its concentration. Moreover, necrostatin-1 recovered cell viability in the presence of shikonin. Elevated ROS levels and mitochondrial dysfunction were also found in shikonin treatment groups. Pretreatment with N-acetyl cysteine remarkably mitigated shikonin-induced cell death and ROS generation. Western blot analysis revealed that shikonin reduced pro-PARP, pro-caspase-3, and Bcl-2 expression and increased cleavage PARP expression. Enhanced autophagy was also found in the shikonin-treated group as evidenced by acridine orange staining. Moreover, light chain 3B (LC3B)-II accumulation and enhanced p62 expression indicated that autophagy occurred in the shikonin-treated group. LC3B knockdown considerably recovered cell viability in the presence of shikonin. Shikonin treatment elevated p38 activity in a dose-dependent manner. In conclusion, our results revealed that shikonin triggered programmed cell death via the elevation of ROS level and p38 activity in different types of RCC cells. These findings suggested that shikonin may be a potential anti-RCC agent.

Promising Protective Effects of Chrysin in Cardiometabolic Diseases

Cardiometabolic diseases (CMD) have a great burden in terms of morbidity and mortality worldwide. The vicious cycle of CMD consists of type II diabetes, hypertension, dyslipidemia, obesity, and atherosclerosis interacting and feedbacking each other. The natural flavonoid chrysin has been displayed to own a broad spectrum of therapeutic impacts for human health. Herein, we did an in-depth investigation of the novel mechanisms of chrysin's cardioprotection against cardiometabolic disorder. Studies have shown that chrysin protects the cardiovascular system by enhancing the intrinsic antioxidative defense system. This antioxidant boost by chrysin protects against several risk factors of cardiometabolic disorders including atherosclerosis, vascular inflammation and dysfunction, platelet aggregation, hypertension, dyslipidemia, cardiotoxicity, myocardial infarction, injury and remodeling, diabetes-induced injuries, and obesity. Chrysin also exhibited anti-inflammatory mechanisms through inhibiting pro-inflammatory pathways including NF-κB, MAPK, and PI3k/Akt. Furthermore, chrysin modulated NO pathway, RAS system, AGE/RAGE pathway, PPARs pathway which contributed to the risk factors of cardiometabolic disorders. Taken together, the mechanisms in which chrysin protects against cardiometabolic disorder are more than merely antioxidation and anti-inflammation in the cardiovascular system.

Modulation of inflammation by phytochemicals to enhance efficacy and reduce toxicity of cancer chemotherapy

Treatment of cancer with chemotherapeutic drugs is associated with numerous adverse effects as well as the eventual development of resistance to chemotherapy. There is a great need for complementary therapies such as botanicals and nutritional supplements with little or no side effects that prevent resistance to chemotherapy and reduce its adverse effects. Inflammation plays a major role in the development of chemoresistance and the adverse effects of chemotherapy. Phytochemicals have well-established anti-inflammatory effects; thus, they could be used as complementary therapies along with chemotherapy to increase its efficacy and reduce its toxicity. Botanical compounds inhibit the NF-κB signaling pathway, which plays an important role in the generation of inflammation, chemotherapy resistance, and modulation of cell survival and apoptosis. Botanicals have previously been studied extensively for their cancer chemopreventive activities and are generally considered safe for human consumption. The present review focuses on the modulation of inflammation by phytochemicals and their role in increasing the efficacy and reducing the toxicity of cancer chemotherapy.

Targeting Autophagy with Natural Compounds in Cancer: A Renewed Perspective from Molecular Mechanisms to Targeted Therapy

Natural products are well-characterized to have pharmacological or biological activities that can be of therapeutic benefits for cancer therapy, which also provide an important source of inspiration for discovery of potential novel small-molecule drugs. In the past three decades, accumulating evidence has revealed that natural products can modulate a series of key autophagic signaling pathways and display therapeutic effects in different types of human cancers. In this review, we focus on summarizing some representative natural active compounds, mainly including curcumin, resveratrol, paclitaxel, Bufalin, and Ursolic acid that may ultimately trigger cancer cell death through the regulation of some key autophagic signaling pathways, such as RAS-RAF-MEK-ERK, PI3K-AKT-mTOR, AMPK, ULK1, Beclin-1, Atg5 and p53. Taken together, these inspiring findings would shed light on exploiting more natural compounds as candidate small-molecule drugs, by targeting the crucial pathways of autophagy for the future cancer therapy.

Autophagy as a Mechanism for Adaptive Prediction-Mediated Emergence of Drug Resistance

Drug resistance is a major problem in treatment of microbial infections and cancers. There is growing evidence that a transient drug tolerant state may precede and potentiate the emergence of drug resistance. Therefore, understanding the mechanisms leading to tolerance is critical for combating drug resistance and for the development of effective therapeutic strategy. Through laboratory evolution of yeast, we recently demonstrated that adaptive prediction (AP), a strategy employed by organisms to anticipate and prepare for a future stressful environment, can emerge within 100 generations by linking the response triggered by a neutral cue (caffeine) to a mechanism of protection against a lethal agent (5-fluoroorotic acid, 5-FOA). Here, we demonstrate that mutations selected across multiple laboratory-evolved lines had linked the neutral cue response to core genes of autophagy. Across these evolved lines, conditional activation of autophagy through AP conferred tolerance, and potentiated subsequent selection of mutations in genes specific to overcoming the toxicity of 5-FOA. These results offer a new perspective on how extensive genome-wide genetic interactions of autophagy could have facilitated the emergence of AP over short evolutionary timescales to potentiate selection of 5-FOA resistance-conferring mutations.

Potential of Bioactive Food Components against Gastric Cancer: Insights into Molecular Mechanism and Therapeutic Targets

Gastric cancer, also known as stomach cancer, is a cancer that develops from the lining of the stomach. Accumulated evidence and epidemiological studies have indicated that bioactive food components from natural products play an important role in gastric cancer prevention and treatment, although its mechanism of action has not yet been elucidated. Particularly, experimental studies have shown that natural bioactive food products display a protective effect against gastric cancer via numerous molecular mechanisms, such as suppression of cell metastasis, anti-angiogenesis, inhibition of cell proliferation, induction of apoptosis, and modulation of autophagy. Chemotherapy remains the standard treatment for advanced gastric cancer along with surgery, radiation therapy, hormone therapy, as well as immunotherapy, and its adverse side effects including neutropenia, stomatitis, mucositis, diarrhea, nausea, and emesis are well documented. However, administration of naturally occurring bioactive phytochemical food components could increase the efficacy of gastric chemotherapy and other chemotherapeutic resistance. Additionally, several studies have suggested that bioactive food components with structural stability, potential bioavailability, and powerful bioactivity are important to develop novel treatment strategies for gastric cancer management, which may minimize the adverse effects. Therefore, the purpose of this review is to summarize the potential therapeutic effects of natural bioactive food products on the prevention and treatment of gastric cancer with intensive molecular mechanisms of action, bioavailability, and safety efficacy.

4-Hydroxyderricin Promotes Apoptosis and Cell Cycle Arrest through Regulating PI3K/AKT/mTOR Pathway in Hepatocellular Cells

4-hydroxyderricin (4-HD), as a natural flavonoid compound derived from Angelica keiskei, has largely unknown inhibition and mechanisms on liver cancer. Herein, we investigated the inhibitory effects of 4-HD on hepatocellular carcinoma (HCC) cells and clarified the potential mechanisms by exploring apoptosis and cell cycle arrest mediated via the PI3K/AKT/mTOR signaling pathway. Our results show that 4-HD treatment dramatically decreased the survival rate and activities of HepG2 and Huh7 cells. The protein expressions of apoptosis-related genes significantly increased, while those related to the cell cycle were decreased by 4-HD. 4-HD also down-regulated PI3K, p-PI3K, p-AKT, and p-mTOR protein expression. Moreover, PI3K inhibitor (LY294002) enhanced the promoting effect of 4-HD on apoptosis and cell cycle arrest in HCC cells. Consequently, we demonstrate that 4-HD can suppress the proliferation of HCC cells by promoting the PI3K/AKT/mTOR signaling pathway mediated apoptosis and cell cycle arrest.

Chrysin induces autophagy through the inactivation of the ROS‑mediated Akt/mTOR signaling pathway in endometrial cancer

Endometrial cancer (EC) is widely known as an aggressive malignancy. Due to the limited therapeutic options and poor prognosis of patients with advanced-stage EC, there is a need to identify effective alternative treatments. Chrysin is a naturally active flavonoid (5,7-dihydroxyflavone), which has been demonstrated to exert anticancer effects and may present a novel strategy for EC treatment. However, the role of chrysin in EC remains largely unclear. The aim of the present study was to examine the anticancer effects of chrysin on EC. The results revealed that, in addition to apoptosis, chrysin increased the LC3II expression levels and markedly accelerated the autophagic flux, suggesting that chrysin induced both the autophagy and apoptosis of EC cells. Furthermore, the inhibition of autophagy by chloroquine enhanced the inhibitory effect on cell proliferation and the promotion of the chrysin-induced apoptosis of EC cells, indicating that chrysin-induced autophagy was a cytoprotective mechanism. Additionally, chrysin led to the production of intracellular reactive oxygen species (ROS). N-acetylcysteine (NAC) pretreatment significantly inhibited chrysin-induced autophagy, suggesting that ROS activated autophagy induced by chrysin in EC cells. Furthermore, the phosphorylated (p-) Akt and p-mTOR levels were significantly decreased in a concentration-dependent manner following treatment with chrysin, while NAC blocked these effects. Taken together, these findings demonstrated that chrysin-induced autophagy via the inactivation of the ROS-mediated Akt/mTOR signaling pathway in EC cells.

The Multifaceted Role of Flavonoids in Cancer Therapy: Leveraging Autophagy with a Double-Edged Sword

Flavonoids are considered as pleiotropic, safe, and readily obtainable molecules. A large number of recent studies have proposed that flavonoids have potential in the treatment of tumors by the modulation of autophagy. In many cases, flavonoids suppress cancer by stimulating excessive autophagy or impairing autophagy flux especially in apoptosis-resistant cancer cells. However, the anti-cancer activity of flavonoids may be attenuated due to the simultaneous induction of protective autophagy. Notably, flavonoids-triggered protective autophagy is becoming a trend for preventing cancer in the clinical setting or for protecting patients from conventional therapeutic side effects in normal tissues. In this review, focusing on the underlying autophagic mechanisms of flavonoids, we hope to provide a new perspective for clinical application of flavonoids in cancer therapy. In addition, we highlight new research ideas for the development of new dosage forms of flavonoids to improve their various pharmacological effects, establishing flavonoids as ideal candidates for cancer prevention and therapy in the clinic.

Cogent role of flavonoids as key orchestrators of chemoprevention of hepatocellular carcinoma: A review

Chemopreventive approaches with food-derived phytochemicals are progressively rising as a significant aspect of tumor management and control. Herein, we have showcased the major phytoconstituents belonging to the group of flavanoid, as anti-cancer agents used for the treatment and prevention of hepatocellular carcinoma (HCC). Sorafenib is the sole drug used for the treatment of advanced HCC, but its clinical application is limited because of its severe adverse effects and drug resistance. Diet-based chemoprevention seems to be the way forward for this disease of malignant nature. As HCC is derived from a chronic inflammatory milieu, the regular incorporation of bioactive phytochemicals in the diet will confer protection and prevent progression to hepatocarcinogenesis. Many preclinical studies proved that the health benefits of flavonoids confer cytotoxic potential against various types of cancers including hepatocellular carcinoma. As flavonoids with excellent safety profile are abundantly present in common vegetables and fruits, they can be better utilized for chemoprevention and chemosensitization in such chronic condition. This review highlights the plausible role of the eight most promising flavonoids (Curcumin, Kaempferol, Resveratrol, Quercetin, Silibinin, Baicalein, Galangin and Luteolin) as key orchestrators of chemoprevention in hepatocellular carcinoma with preclinical and clinical evidence. An attempt to address the challenges in its clinical translation is also included. This review also provides an insight into the close association of HCC and metabolic disorders which may further decipher the chemopreventive effect of dietary bioactive from a proof of concept to extensive clinical translation. PRACTICAL APPLICATIONS: According to GLOBOCAN 2020 database, it is estimated that 905,677 new cases of liver cancer and approximately 830,180 deaths related to that. The cancer incidence and mortality are almost similar as it is diagnosed at an advanced stage in patients where systemic drug therapy is the sole approach. Due to the emergence of multidrug resistance and drug-related toxicities, most of the patient can not adhere to the therapy regimen. Flavonoids are known to be a potential anticancer agent with an excellent safety profile. These are found to be effective preclinically against hepatocellular carcinoma through modulation of numerous pathways in hepatocarcinogenesis. But, the bioavailability issue, lack of well designed-validated clinical evidence, the possibility of food-drug interaction etc limit its clinical utility. The research inputs mainly to overcome pharmacokinetic issues along with suitable validation of efficacy and toxicity will be a critical point for establishing flavonoids as an effective, safe, affordable therapeutics.

Luteolin prevents THP-1 macrophage pyroptosis by suppressing ROS production via Nrf2 activation

Pyroptosis plays an important role in the pathogenesis of numerous infectious, autoimmune, and inflammatory diseases, which makes it a promising target for intervention. In this study, the effect of luteolin on pyroptosis and the underlying mechanism were investigated using the canonical NLRP3 inflammasome in THP-1 macrophages induced by LPS/ATP. The results showed that luteolin exhibited a potent preventive effect on THP-1 macrophage pyroptosis, as evidenced by the increase in cell viability and the decrease in LDH release. Moreover, luteolin was found to significantly reduce the expression of NLRP3, pro-CASP-1 and CASP-1, which are the key components of NLRP3 inflammasome, as well as the expression of N-GSDMD and IL-1β, and we proved that the inhibition of luteolin on NLRP3 inflammasome activation is ROS-dependent. Furthermore, it was demonstrated that luteolin promoted Nrf2 nuclear translocation, thereby increasing the expression of HO-1 that reduces ROS production, while the anti-pyroptotic effect of luteolin was reversed by a specific Nrf2 inhibitor. Additionally, luteolin inhibited NF-κB p65 phosphorylation and nuclear translocation. In summary, we conclude that luteolin prevents THP-1 macrophage pyroptosis by suppressing ROS production via Nrf2 activation as well as NF-κB inactivation. These results support luteolin as a potential bioactive chemical against pyroptosis-related inflammatory diseases.

lncRNA MALAT1 participates in metformin inhibiting the proliferation of breast cancer cell

In recent years, the repurposing of conventional and chemotherapeutic drugs is recognized as an alternative strategy for health care. The main purpose of this study is to strengthen the application of non‐oncological drug metformin on breast cancer treatment in the perspective of epigenetics. In the present study, metformin was found to inhibit cell proliferation, promote apoptosis and induce cell cycle arrest in breast cancer cells at a dose‐dependent manner. In addition, metformin treatment elevated acH3K9 abundance and decreased acH3K18 level. The expression of lncRNA MALAT1, HOTAIR, DICER1‐AS1, LINC01121 and TUG1 was up‐regulated by metformin treatment. In metformin‐treated cells, MALAT1 knock‐down increased the Bax/Bcl2 ratio and enhanced p21 but decreased cyclin B1 expression. The expression of Beclin1, VDAC1, LC3‐II, CHOP and Bip was promoted in the cells received combinatorial treatment of metformin and MALAT1 knock‐down. The reduced phosphorylation of c‐Myc was further decreased in the metformin‐treated cells in combination with MALAT1 knock‐down than metformin treatment alone. Taken together, these results provide a promising repurposed strategy for metformin on cancer treatment by modulating epigenetic modifiers.

Autophagy in Gastric Mucosa: The Dual Role and Potential Therapeutic Target

The incidence of stomach diseases is very high, which has a significant impact on human health. Damaged gastric mucosa is more vulnerable to injury, leading to bleeding and perforation, which eventually aggravates the primary disease. Therefore, the protection of gastric mucosa is crucial. However, existing drugs that protect gastric mucosa can cause nonnegligible side effects, such as hepatic inflammation, nephritis, hypoacidity, impotence, osteoporotic bone fracture, and hypergastrinemia. Autophagy, as a major intracellular lysosome-dependent degradation process, plays a key role in maintaining intracellular homeostasis and resisting environmental pressure, which may be a potential therapeutic target for protecting gastric mucosa. Recent studies have demonstrated that autophagy played a dual role when gastric mucosa exposed to biological and chemical factors. More indepth studies are needed on the protective effect of autophagy in gastric mucosa. In this review, we focus on the mechanisms and the dual role of various biological and chemical factors regulating autophagy, such as Helicobacter pylori, virus, and nonsteroidal anti-inflammatory drugs. And we summarize the pathophysiological properties and pharmacological strategies for the protection of gastric mucosa through autophagy.

The Hallmarks of Flavonoids in Cancer

Flavonoids represent an important group of bioactive compounds derived from plant-based foods and beverages with known biological activity in cells. From the modulation of inflammation to the inhibition of cell proliferation, flavonoids have been described as important therapeutic adjuvants against several diseases, including diabetes, arteriosclerosis, neurological disorders, and cancer. Cancer is a complex and multifactor disease that has been studied for years however, its prevention is still one of the best known and efficient factors impacting the epidemiology of the disease. In the molecular and cellular context, some of the mechanisms underlying the oncogenesis and the progression of the disease are understood, known as the hallmarks of cancer. In this text, we review important molecular signaling pathways, including inflammation, immunity, redox metabolism, cell growth, autophagy, apoptosis, and cell cycle, and analyze the known mechanisms of action of flavonoids in cancer. The current literature provides enough evidence supporting that flavonoids may be important adjuvants in cancer therapy, highlighting the importance of healthy and balanced diets to prevent the onset and progression of the disease.