Resveratrol-induced autophagy and apoptosis in cisplatin-resistant human oral cancer CAR cells: A key role of AMPK and Akt/mTOR signaling

Resveratrol inhibited the metastatic behaviors of cisplatin-resistant human oral cancer cells via phosphorylation of ERK/p-38 and suppression of MMP-2/9

Cisplatin resistance is a major clinical problem in the clinical management of oral squamous cell carcinoma (OSCC) patients. Resveratrol is a natural phytoestrogen with antitumor activities. Whether resveratrol can overcome cisplatin resistance and prevent metastasis in OSCC cells is not known. In this study, we first examined the anti-metastatic capacity of resveratrol and then explored the underlying mechanisms using a cisplatin-resistant human OSCC cell line (CAR). The results demonstrated that at a non-toxic dose range (25 to 75 µM), 24-hr treatment of resveratrol was able to suppress the migration and invasion capacities of CAR cells dose dependently. Interestingly, 50 µM resveratrol treatment could significantly down-regulate the expression of the phosphorylated forms of ERK and p-38, in addition to those of MMP-2 and MMP-9. At the same time, the expression levels of phosphorylated ERK together with those unphosphorylated forms of ERK, p38, and JNK were all insignificantly altered. In conclusion, the signaling cascade for resveratrol's suppression of cisplatin-resistant human oral cancer CAR cells was revealed and summarized. Also the rapid effectiveness in suppressing metastatic behaviors of drug-resistant oral cancer cells of non-toxic resveratrol might extend its application to the drug-resistant oral cancer treatment in the near future. PRACTICAL APPLICATIONS: Based on the evidence we provided in the study, we have proposed a model recording the possible pathway for resveratrol inhibiting the metastasis of cisplatin-resistant oral cancer cells. We suppose this signaling pathway may work in other cancer cell lines, and can be helpful in full understanding of the drug-resistance.

Resveratrol Induces Apoptosis and Attenuates Proliferation of MCF-7 Cells in Combination with Radiation and Hyperthermia

AIM

In the current in vitro study, we tried to examine the possible role of resveratrol as a sensitizer in combination with radiotherapy or hyperthermia.

BACKGROUND

Breast cancer is the most common malignancy for women and one of the most common worldwide. It has been suggested that using non-invasive radiotherapy alone cannot eliminate cancer cells. Hyperthermia, which is an adjuvant modality, induces cancer cell death mainly through apoptosis and necrosis. However, cancer cells can also develop resistance to this modality.

OBJECTIVE

The objective of this study was to determine possible potentiation of apoptosis when MCF-7 cells treated with resveratrol before hyperthermia or radiotherapy.

METHODS

MCF-7 cancer cells were treated with different doses of resveratrol to achieve IC50%. Afterwards, cells treated with the achieved concentration of resveratrol were exposed to radiation or hyperthermia. Proliferation, apoptosis and the expression of pro-apoptotic genes were evaluated using flow cytometry, MTT assay and real-time PCR. Results for each combination therapy were compared to radiotherapy or hyperthermia without resveratrol.

RESULTS

Both irradiation or hyperthermia could reduce the viability of MCF-7 cells. Furthermore, the regulation of Bax and caspase genes increased, while Bcl-2 gene expression reduced. Resveratrol potentiated the effects of radiation and hyperthermia on MCF-7 cells.

CONCLUSION

Results of this study suggest that resveratrol is able to induce the regulation of pro-apoptotic genes and attenuate the viability of MCF-7 cells. This may indicate the sensitizing effect of resveratrol in combination with both radiotherapy and hyperthermia.

The paradox of autophagy in Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder caused by germline mutations in TSC1 or TSC2 genes, which leads to the hyperactivation of the mTORC1 pathway, an important negative regulator of autophagy. This leads to the development of hamartomas in multiple organs. The variability in symptoms presents a challenge for the development of completely effective treatments for TSC. One option is the treatment with mTORC1 inhibitors, which are targeted to block cell growth and restore autophagy. However, the therapeutic effect of rapamycin seems to be more efficient in the early stages of hamartoma development, an effect that seems to be associated with the paradoxical role of autophagy in tumor establishment. Under normal conditions, autophagy is directly inhibited by mTORC1. In situations of bioenergetics stress, mTORC1 releases the Ulk1 complex and initiates the autophagy process. In this way, autophagy promotes the survival of established tumors by supplying metabolic precursors during nutrient deprivation; paradoxically, excessive autophagy has been associated with cell death in some situations. In spite of its paradoxical role, autophagy is an alternative therapeutic strategy that could be explored in TSC. This review compiles the findings related to autophagy and the new therapeutic strategies targeting this pathway in TSC.

CYP1B1 as a therapeutic target in cardio-oncology

Cardiovascular complications have been frequently reported in cancer patients and survivors, mainly because of various cardiotoxic cancer treatments. Despite the known cardiovascular toxic effects of these treatments, they are still clinically used because of their effectiveness as anti-cancer agents. In this review, we discuss the growing body of evidence suggesting that inhibition of the cytochrome P450 1B1 enzyme (CYP1B1) can be a promising therapeutic strategy that has the potential to prevent cancer treatment-induced cardiovascular complications without reducing their anti-cancer effects. CYP1B1 is an extrahepatic enzyme that is expressed in cardiovascular tissues and overexpressed in different types of cancers. A growing body of evidence is demonstrating a detrimental role of CYP1B1 in both cardiovascular diseases and cancer, via perturbed metabolism of endogenous compounds, production of carcinogenic metabolites, DNA adduct formation, and generation of reactive oxygen species (ROS). Several chemotherapeutic agents have been shown to induce CYP1B1 in cardiovascular and cancer cells, possibly via activating the Aryl hydrocarbon Receptor (AhR), ROS generation, and inflammatory cytokines. Induction of CYP1B1 is detrimental in many ways. First, it can induce or exacerbate cancer treatment-induced cardiovascular complications. Second, it may lead to significant chemo/radio-resistance, undermining both the safety and effectiveness of cancer treatments. Therefore, numerous preclinical studies demonstrate that inhibition of CYP1B1 protects against chemotherapy-induced cardiotoxicity and prevents chemo- and radio-resistance. Most of these studies have utilized phytochemicals to inhibit CYP1B1. Since phytochemicals have multiple targets, future studies are needed to discern the specific contribution of CYP1B1 to the cardioprotective and chemo/radio-sensitizing effects of these phytochemicals.

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.

Arctigenin-mediated cell death of SK-BR-3 cells is caused by HER2 inhibition and autophagy-linked apoptosis

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) is well-known as the therapeutic marker in breast cancer. Therefore, we evaluated anti-cancer activity of arctigenin (ATG) on in SK-BR-3 HER2-overexpressing human breast cancer cells.

METHODS

Cell viability and cytotoxicity were analyzed with MTT and colony-forming assay and cell cycle analysis was performed by flow cytometry. The expression and/or phosphorylation of proteins in whole cell lysate and mitochondrial fraction were analyzed by Western blotting. Cellular levels of LC3 and sequestosome 1 (SQSTM1/P62) were observed by immunofluorescence analysis.

RESULTS

The result showed that ATG decreased cell viability of SK-BR-3 cells in a concentration-dependent manner. Moreover, ATG increased the sub G1 population linked to the suppression of HER2/EGFR1 signaling pathway. Furthermore, ATG increased the phosphorylation of H2AX and down-regulated RAD51 and survivin expressions, indicating that ATG induced DNA damage and inhibited the DNA repair system. We also found that cleavages of caspase-7 and PARP by releasing mitochondrial cytochrome c into the cytoplasm were induced by ATG treatment for 72 h through the reduction of Bcl-2 and Bcl-xL levels in mitochondria. In contrast, the levels of LC-3 and SQSTM1/P62 were increased by ATG for 24 h through the Akt/mTOR and AMPK signaling pathway.

CONCLUSIONS

Taken together, this study indicates that autophagy-linked apoptosis is responsible for the anti-cancer activity of ATG in SK-BR-3 cells, and suggests that ATG is considered a potential therapeutic for the treatment of HER2-overexpressing breast cancer.

The anti-melanogenic effects of ellagic acid through induction of autophagy in melanocytes and suppression of UVA-activated α-MSH pathways via Nrf2 activation in keratinocytes

Ellagic acid (EA) is a natural phenol antioxidant in different fruits, vegetables, and nuts. As a copper iron chelator from the tyrosinase enzyme's active site, EA was reported to inhibit melanogenesis in melanocytes. Here, we demonstrated the anti-melanogenic mechanisms of EA through autophagy induction in melanoma B16F10 cells and the role of Nrf2 and UVA (3 J/cm²)-activated α-melanocyte stimulating hormone (α-MSH) pathways in keratinocyte HaCaT cells. In vitro data showed that EA suppressed the tyrosinase activity and melanogenesis by suppressing cAMP-mediated CREB and MITF signaling mechanisms in α-MSH-stimulated B16F10 cells. ERK, JNK, and AKT pathways were involved in this EA-regulated MITF downregulation. Notably, EA induced autophagy in B16F10 cells was evidenced from increased LC3-II accumulation, p62/SQSTM1 activation, ATG4B downregulation, acidic vesicular organelle (AVO) formation, PI3K/AKT/mTOR inhibition, and Beclin-1/Bcl-2 dysregulation. Interestingly, 3-MA (an autophagy inhibitor) pretreatment or LC3 silencing (siRNA transfection) of B16F10 cells significantly reduced EA-induced anti-melanogenic activity. Besides this, in UVA-irradiated keratinocyte HaCaT cells, EA suppressed ROS production and α-MSH generation. Moreover, EA mediated the activation and nuclear translocation of Nrf2, leading to antioxidant γ-GCLC, HO-1, and NQO-1 protein expression in HaCaT cells. However, Nrf2 knockdown has significantly impaired this effect, and there was an uncontrolled ROS generation following UVA irradiation. JNK, PKC, and ROS pathways were involved in the activation of Nrf2 in HaCaT cells. In vivo experiments using the zebrafish model confirmed that EA inhibited tyrosinase activity and endogenous pigmentation. In conclusion, ellagic acid is an effective skin-whitening agent and might be used as a topical applicant.

Flavonoids as natural phenolic compounds and their role in therapeutics: an overview

Background

Natural plants and plant-derived formulations have been used by mankind from the ancient period of time. For the past few years, many investigations elaborated the therapeutic potential of various secondary chemicals present in the plants. Literature revealed that the various secondary metabolites, viz. phenolics and flavonoids, are responsible for a variety of therapeutic action in humans.

Main body

In the present review, an attempt has been made to compile the exploration of natural phenolic compounds with major emphasis on flavonoids and their therapeutic potential too. Interestingly, long-term intake of many dietary foods (rich in phenolics) proved to be protective against the development and management of diabetes, cancer, osteoporosis, cardiovascular diseases and neurodegenerative diseases, etc.

Conclusion

This review presents an overview of flavonoid compounds to use them as a potential therapeutic alternative in various diseases and disorders. In addition, the present understanding of phenolics and flavonoids will serve as the basis for the next scientific studies.

Modulation of Autophagy in Cancer Cells by Dietary Polyphenols

The role of autophagy is to degrade damaged or unnecessary cellular structures. Both in vivo and in vitro studies suggest a dual role of autophagy in cancer—it may promote the development of neoplasms, but it may also play a tumor protective function. The mechanism of autophagy depends on the genetic context, tumor stage and type, tumor microenvironment, or clinical therapy used. Autophagy also plays an important role in cell death as well as in the induction of chemoresistance of cancer cells. The following review describes the extensive autophagic cell death in relation to dietary polyphenols and cancer disease. The review documents increasing use of polyphenolic compounds in cancer prevention, or as agents supporting oncological treatment. Polyphenols are organic chemicals that exhibit antioxidant, anti-inflammatory, anti-angiogenic, and immunomodulating properties, and can also initiate the process of apoptosis. In addition, polyphenols reduce oxidative stress and protect against reactive oxygen species. This review presents in vitro and in vivo studies in animal models with the use of polyphenolic compounds such as epigallocatechin-3-gallate (EGCG), oleuropein, punicalgin, apigenin, resveratrol, pterostilbene, or curcumin and their importance in the modulation of autophagy-induced death of cancer cells.

A novel danshensu/tetramethypyrazine derivative attenuates oxidative stress-induced autophagy injury via the AMPK-mTOR-Ulk1 signaling pathway in cardiomyocytes

Myocardial ischemia/reperfusion injury (MIRI) is an inevitable and unsolved clinical problem in the treatment of ischemic heart diseases. Compound DT-010 is a novel danshensu/tetramethylpyrazine derivative and was examined as a candidate for treating MIRI. In the present study, MTT, lactate dehydrogenase assay and Hoechst staining data indicated that DT-010 attenuated tert-butylhydroperoxide (t-BHP)-induced oxidative damage by increasing cell survival, reducing cell damage and decreasing apoptosis in H9c2 cardiomyocytes. Autophagy was assessed by western blotting for microtubule-associated protein 1A/1B-light chain 3 (LC3-II and LC3-I) expression, acridine orange and monodansylcadaverine staining for autophagosome formation and the monomeric red fluorescent protein-green fluorescent protein-LC3 assay for autophagic flow. t-BHP-induced cell damage was aggravated by the autophagy agonist rapamycin and alleviated by the autophagy blocker hydroxy-chloroquine, suggesting that autophagy was involved in t-BHP-induced cardiomyocyte injury. DT-010 pretreatment significantly prevented t-BHP-induced cell damage, which was partially but significantly abolished by rapamycin and significantly improved by hydroxy-chloroquine treatment. DT-010 treatment inhibited t-BHP-induced autophagy in H9c2 cells, reduced phosphorylation of 5'-AMP-activated protein kinase (AMPK) and promoted the phosphorylation of mTOR and unc-51 like autophagy activating kinase 1 (Ulk1). To conclude, DT-010 can serve as a potential candidate for myocardial ischemia-reperfusion injury therapy. The cardioprotective effects of DT-010 could be partially attributed to its inhibition of autophagy via the AMPK-mTOR-Ulk1 signaling pathway.

New tricks of old drugs: Repurposing non-chemo drugs and dietary phytochemicals as adjuvants in anti-tumor therapies

Combination therapy has long been applied to enhance therapeutic effect and deal with the occurrence of multi-drug resistance in cancer treatment. However, the overlapping toxicity of multiple anticancer drugs to healthy tissues and increasing financial burden on patients emerged as major concerns. As promising alternatives to chemo agents, repurposed non-chemo drugs and dietary phytochemicals have been investigated as adjuvants to conventional anti-tumor therapeutics, offering a safe and economic strategy for combination therapy. In this review, we aim to highlight the advances in research about combination therapy using conventional therapeutics and repurposed drugs or phytochemicals for an enhanced anti-tumor efficacy, along with the mechanisms involved in the synergism. Beyond these, we outlined the potential challenges and solutions for clinical translation of the proposed combination therapy, providing a safe and affordable strategy to improve the reach of cancer therapy to low income regions with such new tricks of old drugs.

Challenges and Therapeutic Opportunities of Autophagy in Cancer Therapy

Simple Summary

Autophagy is a physiological process characterized by the degradation of the cell components through lysosomes due to stimuli/stress. In this study, we review the challenges and therapeutic opportunities that autophagy presents in the treatment of cancer. We discussed the results of several studies that evaluated autophagy as a therapeutic strategy in cancer, both through the modulation of therapeutic resistance and the death of cancer cells. Moreover, we discussed the role of autophagy in the biology of cancer stem cells and the inhibition of this process as a strategy to overcome resistance and progression of cancer stem cells.

Abstract

Autophagy is a physiological cellular process that is crucial for development and can occurs in response to nutrient deprivation or metabolic disorders. Interestingly, autophagy plays a dual role in cancer cells—while in some situations, it has a cytoprotective effect that causes chemotherapy resistance, in others, it has a cytotoxic effect in which some compounds induce autophagy-mediated cell death. In this review, we summarize strategies aimed at autophagy for the treatment of cancer, including studies of drugs that can modulate autophagy-mediated resistance, and/or drugs that cause autophagy-mediated cancer cell death. In addition, the role of autophagy in the biology of cancer stem cells has also been discussed.

Protection Against Ionizing Radiation-Induced Normal Tissue Damage by Resveratrol: A Systematic Review

The use of some agents as radioprotectors has been evaluated for protection against normal tissue toxicity following exposure to ionizing radiation. Resveratrol, a natural flavonoid, with antioxidant and anti-inflammatory properties has attracted research interests for its radioprotective potential. This study systematically evaluates existing studies to examine the radioprotective effectiveness of resveratrol. A literature search of the electronic databases, including PubMed, Scopus, and Embase was conducted to retrieve articles investigating the protective effect of resveratrol against ionizing radiation-induced damage to normal tissues. The search timeframe ranged from the inception of each database to January 2020. From an initial search of 231 articles, and after the removal of duplicates as well as applying the predetermined inclusion and exclusion criteria, 33 articles were finally included for this systematic review. Results showed promising protective effect of resveratrol against ionizing radiation-induced damage to normal tissues. Furthermore, no adverse effect was observed after administering resveratrol. Resveratrol showed the potential to protect against ionizing radiation-induced damage to normal tissue cells via notable mechanisms, including anti-apoptotic and anti-inflammatory effects. However, further studies on the efficacy of clinical translation of resveratrol would open up more insights, while other gray areas such as the optimal radioprotective dosage of resveratrol requires further investigation. Overall, resveratrol is a potential double-edged sword in cancer therapy while protecting healthy tissues.

Saponins Extracted from Tea (Camellia Sinensis) Flowers Induces Autophagy in Ovarian Cancer Cells

Tea flower saponins (TFS) possess effective anticancer properties. The diversity and complexity of TFS increases the difficulty of their extraction and purification from tea flowers. Here, multiple methods including solvent extraction, microporous resin separation and preparative HPLC separation were used to obtain TFS with a yield of 0.34%. Furthermore, we revealed that TFS induced autophagy—as evidenced by an increase in MDC-positive cell populations and mCherry-LC3B-labeled autolysosomes and an upregulation of LC3II protein levels. 3-MA reversed the decrease in cell viability induced by TFS, showing that TFS induced autophagic cell death. TFS-induced autophagy was not dependent on the Akt/mTOR/p70S6K signaling pathway. TFS-induced autophagy in OVCAR-3 cells was accompanied by ERK pathway activation and reactive oxygen species (ROS) generation. This paper is the first report of TFS-mediated autophagy of ovarian cancer cells. These results provide new insights for future studies of the anti-cancer effects of TFS.

Chemotherapeutic efficacy of curcumin and resveratrol against cancer: Chemoprevention, chemoprotection, drug synergism and clinical pharmacokinetics

The frequent inefficiency of conventional cancer therapies due to drug resistance, non-targeted drug delivery, chemotherapy-associated toxic side effects turned the focus to bioactive phytochemicals. In this context, curcumin and resveratrol have emerged as potent chemopreventive and chemoprotective compounds modulating apoptotic and autophagic cell death pathways in cancer in vitro and in vivo. As synergistic agents in combination with clinically established anticancer drugs, the enhanced anticancer activity at reduced chemotherapy-associated toxicity towards normal organs can be explained by improved pharmacokinetics, pharmacodynamics, bioavailability and metabolism. With promising preclinical and clinical applications, the design of drug-loaded nanoparticles, nanocarriers, liposomes and micelles have gained much attention to improve target specificity and drug efficacy. The present review focuses on the molecular modes of chemoprevention, chemoprotection and drug synergism with special emphasis to preclinical and clinical applications, pharmacokinetics, pharmacodynamics and advanced drug delivery methods for the development of next-generation personalized cancer therapeutics.

Therapeutic applications of herbal/synthetic/bio-drug in oral cancer: An update

Oral cancer, as one of the most prevalent and invasive cancers that invade local tissue, can cause metastasis, and have high mortality. In 2018, around 355,000 worldwide oral cancers occurred and resulted in 177,000 deaths. Estimates for the year 2020 include about 53,260 new cases added to previous year's cases, and the estimated death toll from this cancer in 2020 is about 10,750 deaths more than previous years. Despite recent advances in cancer diagnosis and treatment, unfortunately, 50% of people with cancer cannot be cured. Of course, it should be remembered that the type of treatment used greatly influences patient recovery. There are not many choices when it comes to treating oral cancer. Research efforts focusing on the discovery and evolution of innovative therapeutic approaches for oral cancer are essential. Such traditional methods of treating this type of cancer like surgery and chemotherapy, have evolved dramatically during the past thirty to forty years, but they continue to cause panic among patients due to their side effects. Therefore, it is necessary to study and use drugs that are less risky for the patient as well as to provide solutions to reduce chemotherapy-induced adverse events that prevent many therapeutic risks. As mentioned above, this study examines low-risk therapies such as herbal remedies, biological drugs, and synthetic drugs in the hope that they will be useful to physicians, researchers, and scientists around the world.

Recent Advances in Characterizing Natural Products that Regulate Autophagy

Autophagy, an intricate response to nutrient deprivation, pathogen infection, Endoplasmic Reticulum (ER)-stress and drugs, is crucial for the homeostatic maintenance in living cells. This highly regulated, multistep process has been involved in several diseases including cardiovascular and neurodegenerative diseases, especially in cancer. It can function as either a promoter or a suppressor in cancer, which underlines the potential utility as a therapeutic target. In recent years, increasing evidence has suggested that many natural products could modulate autophagy through diverse signaling pathways, either inducing or inhibiting. In this review, we briefly introduce autophagy and systematically describe several classes of natural products that implicated autophagy modulation. These compounds are of great interest for their potential activity against many types of cancer, such as ovarian, breast, cervical, pancreatic, and so on, hoping to provide valuable information for the development of cancer treatments based on autophagy.

Polyphenol-Mediated Autophagy in Cancer: Evidence of In Vitro and In Vivo Studies

One of the hallmarks of cellular transformation is the altered mechanism of cell death. There are three main types of cell death, characterized by different morphological and biochemical features, namely apoptosis (type I), autophagic cell death (type II) and necrosis (type III). Autophagy, or self-eating, is a tightly regulated process involved in stress responses, and it is a lysosomal degradation process. The role of autophagy in cancer is controversial and has been associated with both the induction and the inhibition of tumor growth. Autophagy can exert tumor suppression through the degradation of oncogenic proteins, suppression of inflammation, chronic tissue damage and ultimately by preventing mutations and genetic instability. On the other hand, tumor cells activate autophagy for survival in cellular stress conditions. Thus, autophagy modulation could represent a promising therapeutic strategy for cancer. Several studies have shown that polyphenols, natural compounds found in foods and beverages of plant origin, can efficiently modulate autophagy in several types of cancer. In this review, we summarize the current knowledge on the effects of polyphenols on autophagy, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of polyphenols for envisioning future therapies employing polyphenols as chemoadjuvants.

Has resveratrol a potential for mucopolysaccharidosis treatment?

Mucopolysaccharidoses (MPS) represent a devastating group of lysosomal storage diseases (LSD) affecting approximately 1 in 25,000 individuals, where degradation of glycosaminoglycans (GAG) by lysosomal enzymes is impaired due to mutations causing defects in one of GAG-degrading enzymes. The most commonly used therapy for MPS is enzyme replacement therapy, consisting of application of an active form of the missing enzyme. However, supply of the missing enzyme is not enough in case of MPS types whose symptoms are expressed in central nervous system (CNS), as enzyme does not cross the blood-brain barrier. Moreover, even though enzyme replacement therapy for non-neuronopathic MPS IVA type is approved, it has a limited impact on bone abnormalities, that are one of main symptoms in the disease. Therefore, research into alternative therapeutic approaches for these types of MPS is highly desirable. One such alternative strategy is accelerated degradation of GAG by induction of autophagy. Autophagy is a process of lysosomal degradation of macromolecules that become abnormal or unnecessary for cells. One of the latest discoveries is that GAGs can also be such molecules. Potential drug should also cross blood-brain barrier and be safe in long-term therapy. It seems that one of the polyphenols, resveratrol, can meet the requirements. The mechanism of its action in autophagy stimulation is pleiotropic. Therefore, in this review, we will briefly discuss potential of resveratrol treatment for mucopolysaccharidosis through autophagy stimulation based on research in diseases with similar outcome.

Resveratrol modulates the apoptosis and autophagic death of human lung adenocarcinoma A549 cells via a p53‑dependent pathway: Integrated bioinformatics analysis and experimental validation

Resveratrol (RSV) has been reported to exhibit cytotoxic activity in multiple types of malignant cells; however, the mechanisms underlying the antitumor effects of RSV in non-small-cell lung cancer (NSCLC) cells remain undetermined. Combining bioinformatics analysis with experimental validation, the present study aimed to examine the effects of RSV on the apoptosis and autophagy of A549 NSCLC cells, and to determine the potential underlying molecular mechanisms. Bioinformatics analysis was used to determine the differentially expressed genes (DEGs) and identify the enriched biological functions and pathways associated with these DEGs following RSV treatment. Cell viability was determined by MTT assay, and flow cytometry and TUNEL assay were used to evaluate cell apoptosis. Monodansylcadaverine staining combined with a transmission electron microscope were used to evaluate the extent of autophagy. The expression levels of apoptosis-, autophagy-, or pathway-associated molecular markers were measured by reverse transcription-quantitative PCR and/or western blot analysis. By bioinformatics analysis, a total of 1,031 DEGs were identified in the RSV-treated A549 cells, which were enriched in apoptosis-, or autophagy-related biological functions and the p53 signaling pathway. In validation experiments, RSV significantly reduced cell viability and initiated apoptosis, with an increase in the number of apoptotic cells; it also upregulated cleaved caspase-3 expression and Bax expression, and downregulated the Bcl-2 expression levels. Additionally, there was an increase in the accumulation of green dot-like structures, indicative of autophagic vesicles, observed under a fluorescence microscope, and an increase in the presence of autophagic vacuoles observed using a transmission electron microscope following RSV treatment. Furthermore, the expression levels of the autophagy-related proteins, LC3-II/LC3-I and Beclin-1, were increased and p62 expression was decreased. 3-methyladenine (3-MA), an inhibitor of autophagy, partially reversed the RSV-induced cytotoxic effects, but did not significantly alter the number of apoptotic cells. RSV elevated the p53 levels and decreased the phosphorylated (p-)Mdm2 and p-Akt levels. Pifithrin-α, an inhibitor of p53, partially reduced RSV-induced apoptosis and autophagy. On the whole, the results of the present study demonstrated that RSV initiates the apoptosis and autophagic death of A549 cells via the activation of the p53 signaling pathway, further highlighting the potential of RSV for the treatment of NSCLC.

Effect of Astaxanthin on Activation of Autophagy and Inhibition of Apoptosis in Helicobacter pylori-Infected Gastric Epithelial Cell Line AGS

Helicobacter pylori (H. pylori) infection leads to the massive apoptosis of the gastric epithelial cells, causing gastric ulcers, gastritis, and gastric adenocarcinoma. Autophagy is a cellular recycling process that plays important roles in cell death decisions and can protect cells by preventing apoptosis. Upon the induction of autophagy, the level of the autophagy substrate p62 is reduced and the autophagy-related ratio of microtubule-associated proteins 1A/1B light chain 3B (LC3B)-II/LC3B-I is heightened. AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) are involved in the regulation of autophagy. Astaxanthin (AST) is a potent anti-oxidant that plays anti-inflammatory and anti-cancer roles in various cells. In the present study, we examined whether AST inhibits H. pylori-induced apoptosis through AMPK-mediated autophagy in the human gastric epithelial cell line AGS (adenocarcinoma gastric) in vitro. In this study, H. pylori induced apoptosis. Compound C, an AMPK inhibitor, enhanced the H. pylori-induced apoptosis of AGS cells. In contrast, metformin, an AMPK activator, suppressed H. pylori-induced apoptosis, showing that AMPK activation inhibits H. pylori-induced apoptosis. AST inhibited H. pylori-induced apoptosis by increasing the phosphorylation of AMPK and decreasing the phosphorylation of RAC-alpha serine/threonine-protein kinase (Akt) and mTOR in H. pylori-stimulated cells. The number of LC3B puncta in H. pylori-stimulated cells increased with AST. These results suggest that AST suppresses the H. pylori-induced apoptosis of AGS cells by inducing autophagy through the activation of AMPK and the downregulation of its downstream target, mTOR. In conclusion, AST may inhibit gastric diseases associated with H. pylori infection by increasing autophagy through the activation of the AMPK pathway.

PPARδ is a regulator of autophagy by its phosphorylation

In response to nutrient deficiency, autophagy degrades cytoplasmic materials and organelles in lysosomes, which is nutrient recycling, whereas activation of EGFR mediates autophagy suppression in response to growth factors. It is unclear whether PPARδ could be the regulator of autophagy in response to active EGFR. Here we found that EGFR induced PPARδ phosphorylation at tyrosine-108 leading to increased binding of LC3 to PPARδ by its LIR (LC3 interacting region) motif, consequently, inhibited autophagic flux. Conversely, EGFR inhibitor treatment reversed this event. Furthermore, EGFR-mediated PPARδ phosphorylation at tyrosine-108 led to autophagy inhibition and tumor growth. These findings suggest that PPARδ serves as a regulator of autophagy by its phosphorylation.

Combination of Resveratrol and Quercetin Causes Cell Growth Inhibition, DNA Damage, Cell Cycle Arrest, and Apoptosis in Oral Cancer Cells

Resveratrol and quercetin alone are well reported to have anticancer potential, but their combination studies are very inadequate. We have examined their combination in Cal-33 and SCC-15 oral cancer cells (OCCs) and noncancerous HEK-293 cells. Combination of 10 μM concentration of each resveratrol and quercetin brought additive effect on cellular growth, DNA damage, S-phase cell cycle arrest, and cell death in Cal-33 cells but not in the HEK-293 cells. Augmentation of the cell cycle regulatory protein, Cyclin E, and downregulation of Cyclin A possibly caused S-phase arrest in Cal-33 cancer cells. Comet formation and presence of gamma-H2AX foci confirmed DNA damage, and cleavage of PARP1 and upregulation in Bax level specified apoptosis after combined treatment. Ratio of transcription activation and repression histone marks was found increased after alone as well as combined treatment. Histone deacetylase (HDAC)1, HDAC3, and HDAC8 were downregulated by resveratrol alone and combined treatment. Conclusively, combination of resveratrol and quercetin brings cell growth inhibition, DNA damage, and cell cycle arrest in OCCs but not in normal cells. Additionally, combined treatment causes downregulation of HDACs and apoptosis in cancer cells and it could be an incisive strategy against oral cancer.

Targeting AKT/mTOR in Oral Cancer: Mechanisms and Advances in Clinical Trials

Oral cancer (OC) is a devastating disease that takes the lives of lots of people globally every year. The current spectrum of treatment modalities does not meet the needs of the patients. The disease heterogeneity demands personalized medicine or targeted therapies. Therefore, there is an urgent need to identify potential targets for the treatment of OC. Abundant evidence has suggested that the components of the protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway are intrinsic factors for carcinogenesis. The AKT protein is central to the proliferation and survival of normal and cancer cells, and its downstream protein, mTOR, also plays an indispensable role in the cellular processes. The wide involvement of the AKT/mTOR pathway has been noted in oral squamous cell carcinoma (OSCC). This axis significantly regulates the various hallmarks of cancer, like proliferation, survival, angiogenesis, invasion, metastasis, autophagy, and epithelial-to-mesenchymal transition (EMT). Activated AKT/mTOR signaling is also associated with circadian signaling, chemoresistance and radio-resistance in OC cells. Several miRNAs, circRNAs and lncRNAs also modulate this pathway. The association of this axis with the process of tumorigenesis has culminated in the identification of its specific inhibitors for the prevention and treatment of OC. In this review, we discussed the significance of AKT/mTOR signaling in OC and its potential as a therapeutic target for the management of OC. This article also provided an update on several AKT/mTOR inhibitors that emerged as promising candidates for therapeutic interventions against OC/head and neck cancer (HNC) in clinical studies.

Targeting Autophagic Pathways by Plant Natural Compounds in Cancer Treatment

Nowadays, natural compounds of plant origin with anticancer effects have gained more attention because of their clinical safety and broad efficacy profiles. Autophagy is a multistep lysosomal degradation pathway that may have a unique potential for clinical benefit in the setting of cancer treatment. To retrieve articles related to the study, the databases of Google Scholar, Web of sciences, Medline and Scopus, using the following keywords: Autophagic pathways; herbal medicine, oncogenic autophagic pathways, tumor-suppressive autophagic pathways, and cancer were searched. Although natural plant compounds such as resveratrol, curcumin, oridonin, gossypol, and paclitaxel have proven anticancer potential via autophagic signaling pathways, there is still a great need to find new natural compounds and investigate the underlying mechanisms, to facilitate their clinical use as potential anticancer agents through autophagic induction.

Resveratrol and its Related Polyphenols Contribute to the Maintenance of Genome Stability

Genomic destabilisation is associated with the induction of mutations, including those in cancer-driver genes, and subsequent clonal evolution of cells with abrogated defence systems. Such mutations are not induced when genome stability is maintained; however, the mechanisms involved in genome stability maintenance remain elusive. Here, resveratrol (and related polyphenols) is shown to enhance genome stability in mouse embryonic fibroblasts, ultimately protecting the cells against the induction of mutations in the ARF/p53 pathway. Replication stress-associated DNA double-strand breaks (DSBs) that accumulated with genomic destabilisation were effectively reduced by resveratrol treatment. In addition, resveratrol transiently stabilised the expression of histone H2AX, which is involved in DSB repair. Similar effects on the maintenance of genome stability were observed for related polyphenols. Accordingly, we propose that polyphenol consumption can contribute to the suppression of cancers that develop with genomic instability, as well as lifespan extension.

The Drug-Resistance Mechanisms of Five Platinum-Based Antitumor Agents

Platinum-based anticancer drugs, including cisplatin, carboplatin, oxaliplatin, nedaplatin, and lobaplatin, are heavily applied in chemotherapy regimens. However, the intrinsic or acquired resistance severely limit the clinical application of platinum-based treatment. The underlying mechanisms are incredibly complicated. Multiple transporters participate in the active transport of platinum-based antitumor agents, and the altered expression level, localization, or activity may severely decrease the cellular platinum accumulation. Detoxification components, which are commonly increasing in resistant tumor cells, can efficiently bind to platinum agents and prevent the formation of platinum–DNA adducts, but the adducts production is the determinant step for the cytotoxicity of platinum-based antitumor agents. Even if adequate adducts have formed, tumor cells still manage to survive through increased DNA repair processes or elevated apoptosis threshold. In addition, autophagy has a profound influence on platinum resistance. This review summarizes the critical participators of platinum resistance mechanisms mentioned above and highlights the most potential therapeutic targets or predicted markers. With a deeper understanding of the underlying resistance mechanisms, new solutions would be produced to extend the clinical application of platinum-based antitumor agents largely.

TIPE2 suppressed cisplatin resistance by inducing autophagy via mTOR signalling pathway

Tumour necrosis factor-α-induced protein-8-like-2 (TIPE2) has been associated with the progression of numerous cancers. Cisplatin, as a classical chemotherapy strategy for cancers, has been applied in non-small-cell lung cancer (NSCLC) clinical therapy but bears the disadvantage of chemoresistance. The aim of this study was to investigate the role of TIPE2 in cisplatin resistance and illustrate the detailed molecular mechanism. In this study, we proved that TIPE2 was down-regulated in cisplatin (DDP)-resistant NSCLC tissues and DDP-resistant NSCLC cells compared with the sensitive control. The inhibition of TIPE2 contributed to cell cisplatin-resistance, and the overexpression of TIPE2 enhanced cisplatin sensitivity and autophagy. Furthermore, increased TIPE2 elevated apoptosis in DDP-resistant NSCLC cells. In addition, TIPE2 restored the activity of mTOR signalling. Preconditioning with the mTOR activator 3BDO abrogated TIPE2-mediated depression in cisplatin-evoked autophagy. In conclusion, aberrant TIPE2 expression may contribute to the occurrence of chemoresistance by interfering with autophagy in NSCLC in an mTOR-dependent manner. TIPE2 could be used as a novel therapeutic target to overcome cisplatin-resistant NSCLC.

Differential expression of ghrelin and GHSR via the mTOR pathway during the dynamic carcinogenic process involving oral, potentially malignant disorders

The purpose was to explore the sequence changes in ghrelin and GHSR in the mTOR signaling pathway during carcinogenesis involving oral, potentially malignant disorders (OPMD). The samples were confirmed through in vivo pathologic tissue screening and diagnosis. The immunohistochemical method was used to detect the expression of the ghrelin/growth hormone secretagogue receptor (GHSR) protein. The expression of ghrelin, GHSR 1α, GHSR 1β, and mammalian target of rapamycin (mTOR) RNA were detected by real-time PCR. The expression of ghrelin, GHSR, mTOR, and phosphorylated mTOR (phosphor-mTOR) protein were detected by Western blot. The expression of ghrelin/GHSR increased gradually in the dynamic process of OPMD carcinogenesis. There was a correlation between the increase in ghrelin, GHSR, mTOR, and phospho-mTOR. The in vivo expression of ghrelin/GHSR protein was the most apparent pathologic change from normal-to-mild, moderate, and severe dysplasia, and finally to the dynamic process from normal-to-mild-to-moderate dysplasia. The in vitro cell experiments based on QPCR results also proved that GHSR 1a functional receptor of ghrelin had a peak expression in LEUK-1 cells. In conclusioin, the close relationship between ghrelin and OPMD carcinogenesis can be used as a new biological target to assess the carcinogenesis of OPMD.

Delivery of mesenchymal stem cells-derived extracellular vesicles with enriched miR-185 inhibits progression of OPMD

Oral leukoplakia is one of the most common oral potentially malignant disorders (OPMDs) and its malignant transformation to oral cancer is highly associated with chronic inflammation. Extracellular vesicles (EVs) or exosome-delivered microRNAs modulate inflammatory responses and alleviate irritations that predisposes to cancer. We previously reported that microRNA-185 (miR-185) was significantly decreased in the buccal tissue of patients with oral cancer. In this study, we utilized genetically modified mesenchymal stem cells (MSCs) derived EVs with high expression of miR-185 to pasted MSC-EV-miR-185 on buccal lesions in dimethylbenzanthracene (DMBA) induced OPMD model. We found that treatment with MSC-EV-miR-185 remarkably attenuated inflammation severity and significantly decreased the incidence and the number of dysplasia in the OPMD tissue. Immunohistochemistry showed significantly decreased expression of proliferation marker PCNA and angiogenic marker CD31 in the lesion treated with MSC-EV-miR-185. Furthermore, miR-185 specifically targeted Akt genes by promoting activation of the apoptotic pathway, confirmed by the increased levels of activated caspase-3 and 9. In conclusion, genetically modified MSC-derived EVs enriched with miR-185 alleviate inflammatory response, inhibit cell proliferation and angiogenesis, and induce cell apoptosis, suggesting that their potential role as a novel therapeutic option for OPMD.

Cudraxanthone D Regulates Epithelial-Mesenchymal Transition by Autophagy Inhibition in Oral Squamous Cell Carcinoma Cell Lines

Cudraxanthone D (CD), derived from the root bark of Cudrania tricuspidata, is a natural xanthone compound. However, the biological activity of CD in terms of human metabolism has been barely reported to date. Autophagy is known as a self-degradation process related to cancer cell viability and metastasis. Herein, we investigated the effects of CD on human oral squamous cell carcinoma (OSCC) metastatic related cell phenotype. We confirmed that CD effectively decreased proliferation and viability in a time- and dose-dependent manner in human OSCC cells. In addition, OSCC cell migration, invasion, and EMT were inhibited by CD. To further determine the underlying mechanism of CD's inhibition of cell metastatic potential, we established the relationship between EMT and autophagy in OSCC cells. Thus, our findings indicated that CD inhibited the potential metastatic abilities of OSCC cells by attenuating autophagy.

Resveratrol As A Natural Regulator Of Autophagy For Prevention And Treatment Of Cancer

Resveratrol, as a natural product compound, has been recently attracted much attention for its potent effects on cancer. Cancer is a serious disease threatening human survival and social development. Autophagy is a cellular pathway to realize the metabolic needs of the cell itself and the renewal of some organelles and plays opposing, context-dependent role in tumorigenesis. So the regulation of autophagy is of great significance in the treatment of cancer. p62, as an autophagy adaptor protein, is a preferred target for autophagy and is constantly controlled by constitutive autophagy. As a tumor-suppression mechanism, autophagy deficiency is common in tumors, which results in aberrant accumulation of p62 and activates p62-regulated pathways, such as activation of mTOR in nutrient sensing, and the activation of the Keap1-Nrf2 pathway for antioxidant stress, which are associated with cancer development. In this review, we emphasize that resveratrol can induce autophagy in the treatment of cancer and accelerates the degradation of p62, and then, the mTOR activation is blocked and Nrf2 activation is suppressed. As a result, the multidrug resistance of cancer cells can be reversed by resveratrol.

Ursolic acid induces apoptosis and autophagy in oral cancer cells

Oral squamous cell carcinoma (OSCC) is the fifth common cause of cancer mortality in Taiwan with high incidence and recurrence and needs new therapeutic strategies. In this study, ursolic acid (UA), a triterpenoid, was examined the antitumor potency in OSCC cells. Our results showed that UA inhibited the proliferation of OSCC cells in a dose- and time-dependent manner in both Ca922 and SCC2095 oral cancer cells. UA induced caspase-dependent apoptosis accompanied with the modulation of various biological biomarkers including downregulating Akt/mTOR/NF-κB signaling, ERK, and p38. In addition, UA inhibited angiogenesis as evidenced by abrogation of migration/invasion and blocking MMP-2 secretion in Ca922 cells. Interestingly, UA induced autophagy in OSCC cells, as manifested by LC3B-II conversion and increased p62 expression and accumulation of autophagosomes. Inhibition by autophagy inhibitor enhanced UA-mediated apoptosis in Ca922 cells. The experiment provides a rationale for using triterpenoid in the treatment of OSCC.

Ginsenoside Compound K Induces Ros-Mediated Apoptosis and Autophagic Inhibition in Human Neuroblastoma Cells In Vitro and In Vivo

Autophagy can result in cellular adaptation, as well as cell survival or cell death. Modulation of autophagy is increasingly regarded as a promising cancer therapeutic approach. Ginsenoside compound K (CK), an active metabolite of ginsenosides isolated from Panax ginseng C.A. Meyer, has been identified to inhibit growth of cancer cell lines. However, the molecular mechanisms of CK effects on autophagy and neuroblastoma cell death have not yet been investigated. In the present study, CK inhibited neuroblastoma cell proliferation in vitro and in vivo. Treatment by CK also induced the accumulation of sub-G1 population, and caspase-dependent apoptosis in neuroblastoma cells. In addition, CK promotes autophagosome accumulation by inducing early-stage autophagy but inhibits autophagic flux by blocking of autophagosome and lysosome fusion, the step of late-stage autophagy. This effect of CK appears to be mediated through the induction of intracellular reactive oxygen species (ROS) and mitochondria membrane potential loss. Moreover, chloroquine, an autophagy flux inhibitor, further promoted CK-induced apoptosis, mitochondrial ROS induction, and mitochondria damage. Interestingly, those promoted phenomena were rescued by co-treatment with a ROS scavenging agent and an autophagy inducer. Taken together, our findings suggest that ginsenoside CK induced ROS-mediated apoptosis and autophagic flux inhibition, and the combination of CK with chloroquine, a pharmacological inhibitor of autophagy, may be a novel therapeutic potential for the treatment of neuroblastoma.

Oridonin Sensitizes Cisplatin-Induced Apoptosis via AMPK/Akt/mTOR-Dependent Autophagosome Accumulation in A549 Cells

AMPK-mediated autophagy and Akt/mTOR pathways play important roles in current cancer treatments. Oridonin (Ori), an ent-kaurane diterpenoid isolated from Isodon rubescens, exerts extensive anti-tumor potential and controversial effects on autophagy. In this study, we investigated the effect of Ori on the autophagy, apoptosis, and AMPK/Akt/mTOR pathways and determined whether Ori was related to the increased cisplatin sensitivity observed in A549 cells. First, we found that Ori suppressed Akt/mTOR, Bcl2 and autophagy flux with enhanced levels of Atg3, P62, and LC3II, which was also shown as the accumulation of autophagosomes. AMPK and pro-apoptotic proteins (caspase3, Bax, and PARP) were activated in Ori-treated cells. With the pretreatment of compound c (AMPK inhibitor), the activation of autophagosomes, apoptosis and the inhibition of Akt/mTOR pathways induced by Ori were all reversed. The Ori-activated apoptosis-related markers mentioned previously and the cell-killing effect were restrained by 3-MA (inhibitor of autophagosomes) treatment. Therefore, we hypothesized that the Ori-induced pro-apoptotic effect was mediated by AMPK/Akt/mTOR-dependent accumulation of impaired autophagosomes. Furthermore, Ori could increase the sensitivity of cisplatin through its increased cell-killing, autophagy-suppressing and apoptosis-inducing activities. In addition to sensitizing cisplatin, Ori also alleviated cisplatin-induced acute renal injury in vivo, manifested as depleted BUN, CRE, kidney index, and weight loss compared to the cisplatin group. In summary, apart from its protective effect on cisplatin-induced nephrotoxicity, Ori enhanced cisplatin sensitivity via its pro-apoptotic activity mediated by AMPK/Akt/mTOR-dependent autophagosome activation, which may be a potential therapeutic target for non-small cell lung cancer.

The enigmatic role of matrix metalloproteinases in epithelial-to-mesenchymal transition of oral squamous cell carcinoma: Implications and nutraceutical aspects

The most prevalent malignancy in the oral cavity is represented by oral squamous cell carcinoma, an aggressive disease mostly detected in low-income communities. This neoplasia is mostly diffused in older men particularly exposed to risk factors such as tobacco, alcohol, and a diet rich in fatty foods and poor in vegetables. In oral squamous cell carcinoma, a wide range of matrix-cleaving proteinases are involved in extracellular matrix remodeling of cancer microenvironment. In particular, matrix metalloproteinases (MMPs) represent the major and most investigated protagonists. Owing to their strong involvement in malignant pathologies, MMPs are considered the most promising new biomarkers in cancer diagnosis and prognosis. The interest in studying MMPs in oral cancer biology is also owing to their prominent role in epithelial-to-mesenchymal transition (EMT). EMT is an intricate process involving different complex pathways. EMT-related proteins are attractive diagnostic biomarkers that characterize the activation of biological events that promote cancer's aggressive expansion. Different antioncogenic natural compounds have been investigated to counteract oral carcinogenesis, with the scope of obtaining better clinical results and lower morbidity. In particular, we describe the role of different nutraceuticals used for the regulation of MMP-related invasion and proliferation of oral cancer cells.

The effect of medicinal plants on multiple drug resistance through autophagy: A review of in vitro studies

Multiple drug resistance (MDR) often occurs after prolonged chemotherapy, leading to refractory tumor and cancer recurrence. Autophagy as a primarily process during starvation or stress has a bipolar nature in cancer. It can cause MDR to become more difficult or make resistant cancer cells more susceptible to chemotherapeutic agents. A number of natural products have been introduced to drug discovery for many years. Some of these compounds have been shown to reverse drug resistance by different regulatory mechanisms. In this review, the focus is on the role of medicinal plants in the MDR phenomenon, primarily through the autophagy process.

Direct and Indirect Inhibition Effects of Resveratrol against Toxoplasma gondii Tachyzoites In Vitro

Toxoplasma gondii is one of the most widespread obligatory parasitic protozoa and infects nearly all warm-blooded animals, leading to toxoplasmosis. The therapeutic drugs currently administered, like the combination of pyrimethamine and sulfadiazine, show high rates of toxic side effects, and drug resistance is encountered in some cases. Resveratrol is a natural plant extract with multiple functions, such as antibacterial, anticancer, and antiparasite activities. In this study, we evaluated the inhibitory effects of resveratrol on tachyzoites of the Toxoplasma gondii RH strain extracellularly and intracellularly. We demonstrate that resveratrol possesses direct antitoxoplasma activity by reducing the population of extracellularly grown tachyzoites, probably by disturbing the redox homeostasis of the parasites. Moreover, resveratrol was also able to release the burden of cellular stress, promote apoptosis, and maintain the autophagic status of macrophages, which turned out to be regulated by intracellular parasites, thereby functioning indirectly in eliminating T. gondii In conclusion, resveratrol has both direct and indirect antitoxoplasma effects against RH tachyzoites and may possess the potential to be further evaluated and employed for toxoplasmosis treatment.

AKT as a Therapeutic Target for Cancer

Many cellular processes in cancer are attributed to kinase signaling networks. V-akt murine thymoma viral oncogene homolog (AKT) plays a major role in the PI3K/AKT signaling pathways. AKT is activated by PI3K or phosphoinositide-dependent kinases (PDK) as well as growth factors, inflammation, and DNA damage. Signal transduction occurs through downstream effectors such as mTOR, glycogen synthase kinase 3 beta (GSK3β), or forkhead box protein O1 (FOXO1). The abnormal overexpression or activation of AKT has been observed in many cancers, including ovarian, lung, and pancreatic cancers, and is associated with increased cancer cell proliferation and survival. Therefore, targeting AKT could provide an important approach for cancer prevention and therapy. In this review, we discuss the rationale for targeting AKT and also provide details regarding synthetic and natural AKT-targeting compounds and their associated studies.

Modulation of Autophagy for Controlling Immunity

Autophagy is an essential process that maintains physiological homeostasis by promoting the transfer of cytoplasmic constituents to autophagolysosomes for degradation. In immune cells, the autophagy pathway plays an additional role in facilitating proper immunological functions. Specifically, the autophagy pathway can participate in controlling key steps in innate and adaptive immunity. Accordingly, alterations in autophagy have been linked to inflammatory diseases and defective immune responses against pathogens. In this review, we discuss the various roles of autophagy signaling in coordinating immune responses and how these activities are connected to pathological conditions. We highlight the therapeutic potential of autophagy modulators that can impact immune responses and the mechanisms of action responsible.

Autophagy and its role in gastric cancer

Autophagy, which is tightly regulated by a series of autophagy-related genes (ATGs), is a vital intracellular homeostatic process through which defective proteins and organelles are degraded and recycled under starvation, hypoxia or other specific cellular stress conditions. For both normal cells and tumour cells, autophagy not only sustains cell survival but can also promote cell death. Autophagy-related signalling pathways include mTOR-dependent pathways, such as the AMPK/mTOR and PI3K/Akt/mTOR pathways, and non-mTOR dependent pathways, such as the P53 pathway. Additionally, autophagy plays a dual role in gastric carcinoma (GC), including a tumour-suppressor role and a tumour-promoter role. Long-term Helicobacter pylori infection can impair autophagy, which may eventually promote tumourigenesis of the gastric mucosa. Moreover, Beclin1, LC3 and P62/SQSTM1 are regarded as autophagy-related markers with GC prognostic value. Autophagy inhibitors and autophagy inducers show promise for GC treatment. This review describes research progress regarding autophagy and its significant role in gastric cancer.

Autophagy promotes angiogenesis via AMPK/Akt/mTOR signaling during the recovery of heat-denatured endothelial cells

Our previous study demonstrated that angiogenesis increased during the recovery of heat-denatured endothelial cells. However, the mechanism is still unclear. This study aimed to investigate the relation of autophagy and angiogenesis during the recovery of heat-denatured endothelial cells. A rat deep partial-thickness burn model and heat-denatured human umbilical vein endothelial cells (HUVECs) model (52 °C for 35 s) were used. Autophagy increased significantly in the dermis and HUVECs in a time-dependent manner after heat denaturation and recovery for 2-5 days. Rapamycin-mediated autophagy enhanced the pro-angiogenic effect, evidenced by increased proliferation and migration of HUVECs, and formation of tube-like structures. Autophagy inhibition by 3-Methyladenine (3-MA) abolished the angiogenesis in heat-denatured HUVECs after recovery for 3-5 days. Moreover, heat denaturation augmented the phosphorylation of AMP-activated protein kinase (AMPK) but reduced the phosphorylation of Akt and mTOR in HUVECs. Furthermore, autophagy inhibition by antioxidant NAC, compound C or AMPK siRNA impaired cell proliferation, migration and tube formation heat-denatured HUVECs. At last, the in vivo experiments also showed that inhibition of autophagy by bafilomycin A1 could suppress angiogenesis and recovery of heat-denatured dermis.Taken together, we firstly revealed that autophagy promotes angiogenesis via AMPK/Akt/mTOR signaling during the recovery of heat-denatured endothelial cells and may provide a potential therapeutic target for the recovery of heat-denatured dermis.