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

Autophagy-driven regulation of cisplatin response in human cancers: Exploring molecular and cell death dynamics

Despite the challenges posed by drug resistance and side effects, chemotherapy remains a pivotal strategy in cancer treatment. A key issue in this context is macroautophagy (commonly known as autophagy), a dysregulated cell death mechanism often observed during chemotherapy. Autophagy plays a cytoprotective role by maintaining cellular homeostasis and recycling organelles, and emerging evidence points to its significant role in promoting cancer progression. Cisplatin, a DNA-intercalating agent known for inducing cell death and cell cycle arrest, often encounters resistance in chemotherapy treatments. Recent studies have shown that autophagy can contribute to cisplatin resistance or insensitivity in tumor cells through various mechanisms. This resistance can be mediated by protective autophagy, which suppresses apoptosis. Additionally, autophagy-related changes in tumor cell metastasis, particularly the induction of Epithelial-Mesenchymal Transition (EMT), can also lead to cisplatin resistance. Nevertheless, pharmacological strategies targeting the regulation of autophagy and apoptosis offer promising avenues to enhance cisplatin sensitivity in cancer therapy. Notably, numerous non-coding RNAs have been identified as regulators of autophagy in the context of cisplatin chemotherapy. Thus, therapeutic targeting of autophagy or its associated pathways holds potential for restoring cisplatin sensitivity, highlighting an important direction for future clinical research.

A systematic review and meta-analysis of the impact of resveratrol on oral cancer: potential therapeutic implications

The present study aimed to investigate the impact of resveratrol on oral neoplastic parameters through a systematic review and meta-analysis. Resveratrol, a naturally occurring polyphenol, has shown promising potential as a therapeutic agent in various cancer types, including oral neoplasms. Understanding the collective findings from existing studies can shed light on the efficacy and mechanisms of resveratrol in oral cancer management. The systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search was performed to identify relevant studies from various databases, registers, websites, and citation searches. The inclusion criteria encompassed in-vivo studies investigating the impact of resveratrol on oral neoplastic parameters in animal models. After screening and assessment, a total of five eligible studies were included in the meta-analysis. The meta-analysis of the selected studies revealed that resveratrol treatment exhibited a potential impact on reducing oral neoplastic proliferation and promoting neoplastic apoptosis. The combined analysis showed a statistically significant decrease in neoplastic parameters with an overall effect size (ES) of 0.85 (95% CI: [0.74, 0.98]). Subgroup analyses were conducted to explore potential variations among different cellular types and exposure compounds, providing further insights into the efficacy of resveratrol in specific contexts. This systematic review and meta-analysis support the potential of resveratrol as a promising therapeutic agent in oral cancer management. The findings indicate that resveratrol may effectively modulate neoplastic proliferation and apoptosis in various cellular types within animal models of oral cancer. However, further well-controlled studies and clinical trials are warranted to validate these observations and elucidate the underlying mechanisms of resveratrol's actions. Resveratrol holds promise as a complementary therapeutic approach in the prevention and treatment of oral neoplastic conditions.

Natural products for combating multidrug resistance in cancer

Cancer cells frequently develop resistance to chemotherapeutic therapies and targeted drugs, which has been a significant challenge in cancer management. With the growing advances in technologies in isolation and identification of natural products, the potential of natural products in combating cancer multidrug resistance has received substantial attention. Importantly, natural products can impact multiple targets, which can be valuable in overcoming drug resistance from different perspectives. In the current review, we will describe the well-established mechanisms underlying multidrug resistance, and introduce natural products that could target these multidrug resistant mechanisms. Specifically, we will discuss natural compounds such as curcumin, resveratrol, baicalein, chrysin and more, and their potential roles in combating multidrug resistance. This review article aims to provide a systematic summary of recent advances of natural products in combating cancer drug resistance, and will provide rationales for novel drug discovery.

Natural products reverse cancer multidrug resistance

Cancer stands as a prominent global cause of death. One of the key reasons why clinical tumor chemotherapy fails is multidrug resistance (MDR). In recent decades, accumulated studies have shown how Natural Product-Derived Compounds can reverse tumor MDR. Discovering novel potential modulators to reduce tumor MDR by Natural Product-Derived Compounds has become a popular research area across the globe. Numerous studies mainly focus on natural products including flavonoids, alkaloids, terpenoids, polyphenols and coumarins for their MDR modulatory activity. Natural products reverse MDR by regulating signaling pathways or the relevant expressed protein or gene. Here we perform a deep review of the previous achievements, recent advances in the development of natural products as a treatment for MDR. This review aims to provide some insights for the study of multidrug resistance of natural products.

Selective autophagy in cancer: mechanisms, therapeutic implications, and future perspectives

Eukaryotic cells engage in autophagy, an internal process of self-degradation through lysosomes. Autophagy can be classified as selective or non-selective depending on the way it chooses to degrade substrates. During the process of selective autophagy, damaged and/or redundant organelles like mitochondria, peroxisomes, ribosomes, endoplasmic reticulum (ER), lysosomes, nuclei, proteasomes, and lipid droplets are selectively recycled. Specific cargo is delivered to autophagosomes by specific receptors, isolated and engulfed. Selective autophagy dysfunction is closely linked with cancers, neurodegenerative diseases, metabolic disorders, heart failure, etc. Through reviewing latest research, this review summarized molecular markers and important signaling pathways for selective autophagy, and its significant role in cancers. Moreover, we conducted a comprehensive analysis of small-molecule compounds targeting selective autophagy for their potential application in anti-tumor therapy, elucidating the underlying mechanisms involved. This review aims to supply important scientific references and development directions for the biological mechanisms and drug discovery of anti-tumor targeting selective autophagy in the future.

Moving beyond cisplatin resistance: mechanisms, challenges, and prospects for overcoming recurrence in clinical cancer therapy

Cisplatin, a classical platinum-based chemotherapy agent, has been a frontline treatment for various cancers for decades. However, its effectiveness has been hindered by the development of resistance, leading to cancer relapse. Addressing this challenge is crucial for both clinical practice and research. Hence, the imperative to unravel the intricate mechanisms underpinning cisplatin resistance and to uncover novel strategies to overcome this barrier holds immense significance. Within this review, we summarized the classification of platinum agents, highlighting their roles in therapeutic landscapes. We discussed the diverse mechanisms behind cisplatin resistance, including diminished intracellular cisplatin accumulation, intracellular detoxification, DNA repair, autophagy responses, heat shock proteins, tumor microenvironment, cancer stem cells, epigenetic regulation, ferroptosis resistance, and metabolic reprogramming. Drawing from this comprehensive understanding, we offered a series of prospective solutions to surmount cisplatin resistance and consequently mitigate the specter of disease recurrence within the realm of clinical cancer therapy.

Flavone-based dual PARP-Tubulin inhibitor manifesting efficacy against endometrial cancer

Structural tailoring of the flavone framework (position 7) via organopalladium-catalyzed C-C bond formation was attempted in this study. The impact of substituents with varied electronic effects (phenyl ring, position 2 of the benzopyran scaffold) on the antitumor properties was also assessed. Resultantly, the efforts yielded a furyl arm bearing benzopyran possessing a 4-fluoro phenyl ring (position 2) (14) that manifested a magnificent antitumor profile against the Ishikawa cell lines mediated through dual inhibition of PARP and tubulin [(IC50 (PARP1) = 74 nM, IC50 (PARP2) = 109 nM) and tubulin (IC50 = 1.4 µM)]. Further investigations confirmed the ability of 14 to induce apoptosis as well as autophagy and cause cell cycle arrest at the G2/M phase. Overall, the outcome of the study culminated in a tractable dual PARP-tubulin inhibitor endowed with an impressive activity profile against endometrial cancer.

Effects and mechanisms of resveratrol for prevention and management of cancers: An updated review

Cancer is a severe public health problem. Resveratrol is a famous natural compound that has various bioactivities, such as antioxidant, anti-inflammatory, antidiabetic and antiaging activities. Especially, resveratrol could prevent and treat various cancers, such as oral, thyroid, breast, lung, liver, pancreatic, gastric, colorectal, bladder, prostate and ovarian cancers. The underlying mechanisms have been widely studied, such as inhibiting cell proliferation, suppressing metastasis, inducing apoptosis, stimulating autophagy, modulating immune system, attenuating inflammation, regulating gut microbiota and enhancing effects of other anticancer drugs. In this review, we summarize effects and mechanisms of resveratrol on different cancers. This paper is helpful to develop resveratrol, crude extract containing resveratrol, or foods containing resveratrol into functional food, dietary supplements or auxiliary agents for prevention and management of cancers.

Exploring the potential of dietary factors and plant extracts as chemopreventive agents in oral squamous cell carcinoma treatment

Oral cancer, particularly oral squamous cell carcinoma (OSCC), is a prevalent malignancy having a significant fatality rate worldwide. Despite advancements in conventional treatment modalities, the overall survival rate for OSCC remains low. Therefore, there is a critical need to explore alternative therapeutic approaches that can improve patient outcomes. This review focuses on the potential of dietary factors and plant extracts as chemopreventive agents in treating oral cancer. These compounds possess diverse biological functions encompassing a range of attributes, such as antioxidative, anti-inflammatory, and anticancer capabilities. By targeting multiple cellular pathways involved in carcinogenesis, they possess the capacity to hinder tumor growth and development, promote programmed cell death, and impede the progression of oral cancer. Signaling pathways targeted by natural compounds that have been included in this review include Akt/mTOR/NF-κB signaling, Hippo-Tafazzin signaling pathway, notch signaling pathway, mitochondrial pathway, and Sonic Hedgehog pathway.

Therapeutic strategies targeting AMPK-dependent autophagy in cancer cells

Macroautophagy is a health-modifying process of engulfing misfolded or aggregated proteins or damaged organelles, coating these proteins or organelles into vesicles, fusion of vesicles with lysosomes to form autophagic lysosomes, and degradation of the encapsulated contents. It is also a self-rescue strategy in response to harsh environments and plays an essential role in cancer cells. AMP-activated protein kinase (AMPK) is the central pathway that regulates autophagy initiation and autophagosome formation by phosphorylating targets such as mTORC1 and unc-51 like activating kinase 1 (ULK1). AMPK is an evolutionarily conserved serine/threonine protein kinase that acts as an energy sensor in cells and regulates various metabolic processes, including those involved in cancer. The regulatory network of AMPK is complicated and can be regulated by multiple upstream factors, such as LKB1, AKT, PPAR, SIRT1, or noncoding RNAs. Currently, AMPK is being investigated as a novel target for anticancer therapies based on its role in macroautophagy regulation. Herein, we review the effects of AMPK-dependent autophagy on tumor cell survival and treatment strategies targeting AMPK.

Tumor microenvironment remodeling in oral cancer: Application of plant derived-natural products and nanomaterials

Oral cancers consist of squamous cell carcinoma (SCC) and other malignancies in the mouth with varying degrees of invasion and differentiation. For many years, different modalities such as surgery, radiation therapy, and classical chemotherapy drugs have been used to control the growth of oral tumors. Nowadays, studies have confirmed the remarkable effects of the tumor microenvironment (TME) on the development, invasion, and therapeutic resistance of tumors like oral cancers. Therefore, several studies have been conducted to modulate the TME in various types of tumors in favor of cancer suppression. Natural products are intriguing agents for targeting cancers and TME. Flavonoids, non-flavonoid herbal-derived molecules, and other natural products have shown promising effects on cancers and TME. These agents, such as curcumin, resveratrol, melatonin, quercetin and naringinin have demonstrated potency in suppressing oral cancers. In this paper, we will review and discuss about the potential efficacy of natural adjuvants on oral cancer cells. Furthermore, we will review the possible therapeutic effects of these agents on the TME and oral cancer cells. Moreover, the potential of nanoparticles-loaded natural products for targeting oral cancers and TME will be reviewed. The potentials, gaps, and future perspectives for targeting TME by nanoparticles-loaded natural products will also be discussed.

Resveratrol-Laden Nano-Systems in the Cancer Environment: Views and Reviews

The genesis of cancer is a precisely organized process in which normal cells undergo genetic alterations that cause the cells to multiply abnormally, colonize, and metastasize to other organs such as the liver, lungs, colon, and brain. Potential drugs that could modify these carcinogenic pathways are the ones that will be used in clinical trials as anti-cancer drugs. Resveratrol (RES) is a polyphenolic natural antitoxin that has been utilized for the treatment of several diseases, owing to its ability to scavenge free radicals, control the expression and activity of antioxidant enzymes, and have effects on inflammation, cancer, aging, diabetes, and cardioprotection. Although RES has a variety of pharmacological uses and shows promising applications in natural medicine, its unpredictable pharmacokinetics compromise its therapeutic efficacy and prevent its use in clinical settings. RES has been encapsulated into various nanocarriers, such as liposomes, polymeric nanoparticles, lipidic nanocarriers, and inorganic nanoparticles, to address these issues. These nanocarriers can modulate drug release, increase bioavailability, and reach therapeutically relevant plasma concentrations. Studies on resveratrol-rich nano-formulations in various cancer types are compiled in the current article. Studies relating to enhanced drug stability, increased therapeutic potential in terms of pharmacokinetics and pharmacodynamics, and reduced toxicity to cells and tissues are the main topics of this research. To keep the readers informed about the current state of resveratrol nano-formulations from an industrial perspective, some recent and significant patent literature has also been provided. Here, the prospects for nano-formulations are briefly discussed, along with machine learning and pharmacometrics methods for resolving resveratrol's pharmacokinetic concerns.

Molecular pathways modulated by phytochemicals in head and neck cancer

In the last few years, natural dietary phytochemicals have shown immense potential in the suppression and incidence of Head and Neck Cancer (HNC). From various in-vitro, animal, and epidemiological studies it is now clear that intake of foods rich in dietary phytochemicals lower the risk of HNC. These phytochemicals have been reported to target different stages of Head and Neck cancer (initiation to promotion) by modulating many cellular signaling pathways. A single phytochemical may target different pathways simultaneously or a single pathway may be targeted by a diversity of phytochemicals. This review highlights the molecular pathways modulated by a large number of phytochemicals relevant to HNC with an intent to identify specific signaling pathways that could be therapeutically targeted. Therefore, relevant literature was screened and scrutinized for molecular details. We have focused on the complexity of the molecular mechanisms that are modulated by various phytochemicals and the role they can play in better clinical efficacy and management of head and neck cancer. In-depth knowledge of these molecular mechanisms can lead to innovative therapeutic strategies using phytochemicals alone or along with available treatments for various cancers including HNC. Molecular pathways modulated by Phytochemicals.

The Protective Role of Cranberries and Blueberries in Oral Cancer

BACKGROUND

Oral cancer has a high prevalence worldwide, and this disease is caused by genetic, immunological, and environmental factors. The main risk factors associated with oral cancer are smoking and alcohol.

RESULTS

There are various strategies to reduce risk factors, including prevention programs as well as the consumption of an adequate diet that includes phytochemical compounds derived from cranberries (Vaccinium macrocarpon A.) and blueberries (Vaccinium corymbosum L.); these compounds exhibit antitumor properties.

RESULTS

The main outcome of this review is as follows: the properties of phytochemicals derived from cranberries were evaluated for protection against risk factors associated with oral cancer.

CONCLUSIONS

The secondary metabolites of cranberries promote biological effects that provide protection against smoking and alcoholism. An alternative for the prevention of oral cancer can be the consumption of these cranberries and blueberries.

Resveratrol downregulates ENaCs through the activation of AMPK in human colon cancer cells

Epithelial sodium channels (ENaCs) are critically engaged in a number of hallmarks of cancer progression, including proliferation, migration, invasion and apoptosis. Thus, the inhibition of ENaCs possesses therapeutic potential in cancer. Resveratrol, a natural polyphenol with anti-carcinogenic activity, is a potent activator of 5' AMP-activated protein kinase (AMPK) which reduces the abundance of ENaCs in the cell membrane by causing the internalization of the β subunit. However, the effect of resveratrol on ENaCs in cancer cells is unknown. Therefore, in this study, we aimed to investigate the effects of resveratrol on ENaCs in human colon cancer cells HCT116 and HT29. The influences of resveratrol either alone or together with AMPK inhibitor compound C (CC), and ENaC inhibitor amiloride on cell viability were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The expression levels of phospho-AMPK Thr¹⁷² and βENaC in cells were determined by immunofluorescence staining, and the expression of apoptotic markers Caspase-3 and Caspase-9 were analyzed by qRT-PCR. Resveratrol was found to activate AMPK in a dose-dependent manner. Both AMPK activation by resveratrol and ENaC inhibition by amiloride decreased cell viability and increased apoptosis significantly. AMPK activation also reduced βENaC expression in cells. Our results suggest that ENaC inhibition through AMPK activation might be a potential mechanism underlying the anti-cancer effects of resveratrol.

Resveratrol reverses TGF-β1-mediated invasion and metastasis of breast cancer cells via the SIRT3/AMPK/autophagy signal axis

Resveratrol (Resv) has antitumorigenic and antimetastatic activities; however, the molecular mechanisms underlying the inhibitory effects of Resv on the invasion and metastasis of breast cancer cells are still a subject of debate. In our study, we demonstrated that Resv inhibited tumor cell proliferation and tumor growth. It also suppressed invasion and pulmonary metastasis of breast cancer by reversing the transforming growth factor beta 1 (TGF-β1)-mediated EMT process. Meanwhile, the anticarcinogenic effects of Resv were abolished by the autophagy blocker 3-methyladenine (3-MA) or Beclin 1 small interfering RNA. Moreover, Resv upregulated autophagy-related genes and protein levels and induced the formation of autophagosomes in 4T1 breast cancer cells and xenograft mice, suggesting that autophagy was involved in the anticarcinogenic activities of Resv in both models. In addition, Resv-induced autophagy by increasing the expression of SIRT3 and phosphorylated AMPK. SIRT3 knockdown reduced AMPK phosphorylation and autophagy-related proteins levels, and suppressed the anticancer effects of Resv, demonstrating that the inhibitory effects of Resv on tumor progression were mediated via the SIRT3/AMPK/autophagy pathway. Taken together, our study provided novel insight into the anticancer effects of Resv and revealed that targeting the SIRT3/AMPK/autophagy pathway can serve as a new therapeutic target against breast cancer.

Design, Synthesis and Antiproliferative Evaluation of Bis-Indole Derivatives with a Phenyl Linker: Focus on Autophagy

This work deals with the study of the synthesis of new bis-indole analogues with a phenyl linker derived from indole phytoalexins. Synthesis of target bis-indole thiourea linked by a phenyl linker was achieved by the reaction of [1-(tert-butoxycarbonyl)indol-3-yl]methyl isothiocyanate with p-phenylenediamine. By replacing the sulfur of the thiocarbonyl group in bis-indole thiourea with oxygen using mesityl nitrile oxide, a bis-indole homodimer with a urea group was obtained. A cyclization protocol utilizing bis-indole thiourea and methyl bromoacetate was applied to synthesize a bis-indole homodimer with a thiazolidin-4-one moiety. Bis-indole homodimers derived from 1-methoxyspirobrassinol methyl ether were prepared by bromospirocyclization methodology. Among the synthesized analogues, compound 49 was selected for further study. To evaluate the mode of the mechanism of action, we used flow cytometry, Western blot, and spectroscopic analyses. Compound 49 significantly inhibited the proliferation of lung cancer cell line A549 with minimal effects on the non-cancer cells. We also demonstrated that compound 49 induced autophagy through the upregulation of Beclin-1, LC3A/B, Atg7 and AMPK and ULK1. Furthermore, chloroquine (CQ; an autophagy inhibitor) in combination with compound 49 decreased cell proliferation and induced G1 cell cycle arrest and apoptosis. Compound 49 also caused GSH depletion and significantly potentiated the antiproliferative effect of cis-platin.

Characterization of the chemical constituents and metabolic profile of Polygonum cuspidatum Sieb. et Zucc. in rat plasma, urine, and feces by ultra-high performance liquid chromatography coupled with Quadrupole-Exactive Orbitrap mass spectrometry

Polygonum cuspidatum Sieb. et Zucc. is a traditional and popular Chinese medicine with a wide spectrum of pharmacological effects such as anti-bacterial, anti-inflammatory, and anti-tumor activities together with other health effects like lowering lipids, preventing diabetes, and regulating the immune system. It is of great significance to explore the complex chemical constituents and metabolic process of Polygonum cuspidatum in vivo to further clarify the effective substances. However, studies on its metabolism in vivo were not comprehensive in previous literature. In this study, ultra-high performance liquid chromatography coupled with Quadrupole-Exactive Orbitrap mass spectrometry was used to comprehensively identify the chemical constituents in Polygonum cuspidatum and further analyze its metabolic profile in rats. Compared with reference substances, various databases, and literature retrieval, 62 compounds were inferred from the Polygonum cuspidatum extract. Furthermore, a total of 119 compounds, including 44 prototype compounds and 75 metabolites, were annotated in rat plasma, urine, and feces. The main metabolic pathways of Polygonum cuspidatum in rats included hydrogenation reduction, hydroxylation, dehydration, methylation, sulfation, and glucuronidation. This is the first systematic study on the chemical constituents of Polygonum cuspidatum and its metabolic profile in vivo, which contributes to finding its bioactive components and seeking its therapeutic targets.

Mechanism of Resveratrol-Induced Programmed Cell Death and New Drug Discovery against Cancer: A Review

Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a polyphenol found in grapes, red wine, peanuts, and apples, has been reported to exhibit a wide range of biological and pharmacological properties. In addition, resveratrol has been reported to intervene in multiple stages of carcinogenesis. It has also been known to kill several human cancer cells through programmed cell death (PCD) mechanisms such as apoptosis, autophagy, and necroptosis. However, resveratrol has limitations in its use as an anticancer agent because it is susceptible to photoisomerization owing to its unstable double bond, short half-life, and is rapidly metabolized and eliminated. Trans-(E)-resveratrol is nontoxic, and has several biological and pharmacological activities. However, little is known about the pharmacological properties of the photoisomerized cis-(Z)-resveratrol. Therefore, many studies on resveratrol derivatives and analogues that can overcome the shortcomings of resveratrol and increase its anticancer activity are underway. This review comprehensively summarizes the literature related to resveratrol-induced PCD, such as apoptosis, autophagy, necroptosis, and the development status of synthetic resveratrol derivatives and analogues as novel anticancer drugs.

Focusing on the Role of Natural Products in Overcoming Cancer Drug Resistance: An Autophagy-Based Perspective

Autophagy is a critical cellular adaptive response in tumor formation. Nutritional deficiency and hypoxia exacerbate autophagic flux in established malignancies, promoting tumor cell proliferation, migration, metastasis, and resistance to therapeutic interventions. Pro-survival autophagy inhibition may be a promising treatment option for advanced cancer. Furthermore, excessive or persistent autophagy is cytotoxic, resulting in tumor cell death. Targeted autophagy activation has also shown significant promise in the fight against tumor drug resistance. Several research groups have examined the ability of natural products (NPs) such as alkaloids, terpenoids, polyphenols, and anthraquinones to serve as autophagy inhibitors or activators. The data support the capacity of NPs that promote lethal autophagy or inhibit pro-survival autophagy from being employed against tumor drug resistance. This paper discusses the potential applications of NPs that regulate autophagy in the fight against tumor drug resistance, some limitations of the current studies, and future research needs and priorities.

Disease-associated regulation of gene expression by resveratrol: Special focus on the PI3K/AKT signaling pathway

Resveratrol (3,5,4′-trihydroxy-trans-stilbene) is a natural phenol that is present in the skin of the grape, blueberry, raspberry, mulberry, and peanut. This substance is synthesized in these plants following injury or exposure to pathogens. Resveratrol is used as a dietary supplement for a long time and its effects have been assessed in animal models of human disorders. It has potential beneficial effects in diverse pathological conditions such as diabetes mellitus, obesity, hypertension, neoplastic conditions, Alzheimer's disease, and cardiovascular disorders. Notably, resveratrol has been found to affect the expression of several genes including cytokine coding genes, caspases, matrix metalloproteinases, adhesion molecules, and growth factors. Moreover, it can modulate the activity of several signaling pathways such as PI3K/AKT, Wnt, NF-κB, and Notch pathways. In the current review, we summarize the results of studies that reported modulatory effects of resveratrol on the expression of genes and the activity of signaling pathways. We explain these results in two distinct sections of non-neoplastic and neoplastic conditions.

MAPK Signaling Pathway in Oral Squamous Cell Carcinoma: Biological Function and Targeted Therapy

Oral squamous cell carcinoma accounts for 95% of human head and neck squamous cell carcinoma cases. It is highly malignant and aggressive, with a poor prognosis and a 5-year survival rate of <50%. In recent years, basic and clinical studies have been performed on the role of the mitogen-activated protein kinase (MAPK) signaling pathway in oral cancer. The MAPK signaling pathway is activated in over 50% of human oral cancer cases. Herein, we review research progress on the MAPK signaling pathway and its potential therapeutic mechanisms and discuss its molecular targeting to explore its potential as a therapeutic strategy for oral squamous cell carcinoma.

Dasatinib enhances curcumin-induced cytotoxicity, apoptosis and protective autophagy in human schwannoma cells HEI-193: The role of Akt/mTOR/p70S6K signalling pathway

The present study was carried out in human schwannoma cells (HEI-193) to determine the combined anti-cancer effect of curcumin and dasatinib. Cells were treated with curcumin only, dasatinib only, or the combination of curcumin and dasatinib for 24 hours. Cellular toxicity, cell proliferation, and cell death were determined by LDH, MTT, and trypan blue dye assays, respectively. ELISA based kit was used to determine apoptotic cell death. Western blotting was used to determine the expression of apoptotic and autophagy-associated protein markers. Similarly, expression levels of Akt/mTOR/p70S6K signalling pathway-related proteins were studied using Western blotting. Cell death and apoptosis were significantly higher in HEI-193 cells treated with curcumin and dasatinib combination compared to individual controls. The combination of curcumin and dasatinib significantly enhances autophagy markers compared to individual controls. Furthermore, the combination of curcumin and dasatinib significantly activates Akt/mTOR/p70S6K signalling pathway compared to individual controls. In conclusion, our results suggest that the combination of curcumin and dasatinib significantly enhances cytotoxicity, apoptosis, and protective autophagy in HEI-193 cells through Akt/mTOR/p70S6K signalling pathway.

A renewed concept on the MAPK signaling pathway in cancers: Polyphenols as a choice of therapeutics

Abnormalities in the mitogen-activated protein kinase (MAPK) signaling pathway are a key contributor to the carcinogenesis process and have therefore been implicated in several aspects of tumorigenesis, including cell differentiation, proliferation, invasion, angiogenesis, apoptosis, and metastasis. This pathway offers multiple molecular targets that may be modulated for anticancer activity and is of great interest for several malignancies. Polyphenols from various dietary sources have been observed to interfere with certain aspects of this pathway and consequently play a substantial role in the development and progression of cancer by suppressing cell growth, inactivating carcinogens, blocking angiogenesis, causing cell death, and changing immunity. A good number of polyphenolic compounds have shown promising outcomes in numerous pieces of research and are currently being investigated clinically to treat cancer patients. The current study concentrates on the role of the MAPK pathway in the development and metastasis of cancer, with particular emphasis on dietary polyphenolic compounds that influence the different MAPK sub-pathways to obtain an anticancer effect. This study aims to convey an overview of the various aspects of the MAPK pathway in cancer development and invasion, as well as a review of the advances achieved in the development of polyphenols to modulate the MAPK signaling pathway for better treatment of cancer.

Stellettin B-Induced Oral Cancer Cell Death via Endoplasmic Reticulum Stress-Mitochondrial Apoptotic and Autophagic Signaling Pathway

Oral squamous cell carcinoma (OSCC) affects tens of thousands of people worldwide. Despite advances in cancer treatment, the 5-year survival rate of patients with late-stage OSCC is low at 50–60%. Therefore, the development of anti-OSCC therapy is necessary. We evaluated the effects of marine-derived triterpene stellettin B in human OC2 and SCC4 cells. Stellettin B dose-dependently decreased the viability of both cell lines, with a significant reduction in OC2 cells at ≥0.1 µM at 24 and 48 h, and in SCC4 cells at ≥1 µM at 24 and 48 h. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive cells were significantly observed at 20 µM of stellettin B at 48 h, with the overexpression of cleaved caspase3 and cleaved poly(ADP-ribose) polymerase (PARP). Moreover, mitochondrial respiratory functions were ablated by stellettin B. Autophagy-related LC3-II/LC3-I ratio and Beclin-1 proteins were increased, whereas p62 was decreased. At 20 µM at 48 h, the expression levels of the endoplasmic reticulum (ER) stress biomarkers calnexin and BiP/GRP78 were significantly increased and mitogen-activated protein kinase (MAPK) signaling pathways were activated. Further investigation using the autophagy inhibitor 3-methyladenine (3-MA) demonstrated that it alleviated stellettin B-induced cell death and autophagy. Overall, our findings show that stellettin B induces the ER stress, mitochondrial stress, apoptosis, and autophagy, causing cell death of OSCC cells.

Gitogenin suppresses lung cancer progression by inducing apoptosis and autophagy initiation through the activation of AMPK signaling

Lung cancer is a leading cause of tumor-associated death worldwide. Autophagy plays a key role in regulating lung cancer progression, and is a promising option for lung cancer treatment. Saponins are a group of naturally occurring plant glycosides, characterized by their strong foam-forming properties in aqueous solution, and exert various biological properties, such as anti-inflammation and anti-cancer. In the present study, we for the first time explored the effects of gitogenin (GIT), an important saponin derived from Tribulus longipetalus, on lung cancer progression both in vitro and in vivo. We found that GIT markedly reduced the proliferation and induced apoptosis in lung cancer cells through increasing the cleavage of Caspase-3 and poly (ADP-ribose) polymerases (PARPs). In addition, GIT-incubated lung cancer cells exhibited clear accumulation of autophagosome, which was essential for GIT-suppressed lung cancer. Mechanistically, GIT-induced autophagy initiation was mainly through activating AMP-activated protein kinase (AMPK) and blocking protein kinase B (AKT) signaling pathways, respectively. Moreover, the autophagic flux was disrupted in GIT-treated lung cancer cells, contributing to the accumulation of impaired autophagolysosomes. Importantly, we found that suppressing autophagy initiation could abolish GIT-induced cell death; however, autophagosomes accumulation sensitized lung cancer cells to cell death upon GIT treatment. More in vitro experiments showed that GIT led to reactive oxygen species (ROS) production in lung cancer cells, which was also involved in the modulation of apoptosis. The in vivo findings confirmed the effects of GIT against lung cancer progression with undetectable toxicity to organs. In conclusion, we provided new insights into the treatment of lung cancer, and GIT might be an effective strategy for future clinical application.

MTH-3 sensitizes oral cancer cells to cisplatin via regulating TFEB

OBJECTIVES

MTH-3, a curcumin derivative, exhibits improved water solubility. This study aims to elucidate the mechanisms underlying the anticancer effects of MTH-3 on human oral squamous cell carcinoma CAL27 cisplatin-resistant (CAR) cells.

METHODS

To evaluate the biological functions of MTH-3 in CAR cells, flow cytometry, staining, and western blot analyses were used.

KEY FINDINGS

MTH-3 reduced CAR cell viability and significantly induced autophagy in the presence of 10 and 20 μM MTH-3. Transcription factor EB was identified as the potential target of MTH-3. Autophagy-related proteins were upregulated after 24 h of MTH-3 incubation. MTH-3 treatment increased caspase-3 and caspase-9 enzyme activities. Mitochondrial membrane potential was decreased after MTH-3 treatment. MTH-3 triggered the intrinsic apoptotic pathway.

CONCLUSIONS

MTH-3 induces autophagy and apoptosis of CAR cells via TFEB. MTH-3 might be an effective pharmacological agent for treating oral cancer cells.

Resveratrol as a modulatory of apoptosis and autophagy in cancer therapy

Cancer is one of the leading causes of death, with a heavy socio-economical burden for countries. Despite the great advances that have been made in the treatment of cancer, chemotherapy is still the most common method of treatment. However, many side effects, including hepatotoxicity, renal toxicity, and cardiotoxicity, limit the efficacy of conventional chemotherapy. Over recent years, natural products have attracted attention as therapeutic agents against various diseases, such as cancer. Resveratrol (RES), a natural polyphenol occurring in grapes, nuts, wine, and berries, exhibited potential for preventing and treating various cancer types. RES also ameliorates chemotherapy-induced detrimental effects. Furthermore, RES could modulate apoptosis and autophagy as the main forms of cancer cell deaths by targeting various signaling pathways and up/downregulation of apoptotic and autophagic genes. This review will summarize the anti-cancer effects of RES and focus on the fundamental mechanisms and targets for modulating apoptosis and autophagy by RES.

Applications of resveratrol in the treatment of gastrointestinal cancer

Natural product compounds have lately attracted interest in the scientific community as a possible treatment for gastrointestinal (GI) cancer, due to their anti-inflammatory and anticancer properties. There are many preclinical, clinical, and epidemiological studies, suggesting that the consumption of polyphenol compounds, which are abundant in vegetables, grains, fruits, and pulses, may help to prevent various illnesses and disorders from developing, including several GI cancers. The development of GI malignancies follows a well-known path, in which normal gastrointestinal cells acquire abnormalities in their genetic composition, causing the cells to continuously proliferate, and metastasize to other sites, especially the brain and liver. Natural compounds with the ability to affect oncogenic pathways might be possible treatments for GI malignancies, and could easily be tested in clinical trials. Resveratrol is a non-flavonoid polyphenol and a natural stilbene, acting as a phytoestrogen with anti-cancer, cardioprotective, anti-oxidant, and anti-inflammatory properties. Resveratrol has been shown to overcome resistance mechanisms in cancer cells, and when combined with conventional anticancer drugs, could sensitize cancer cells to chemotherapy. Several new resveratrol analogs and nanostructured delivery vehicles with improved anti-GI cancer efficacy, absorption, and pharmacokinetic profiles have already been developed. This present review focuses on the in vitro and in vivo effects of resveratrol on GI cancers, as well as the underlying molecular mechanisms of action.

Potential Therapeutic Targets of Resveratrol, a Plant Polyphenol, and Its Role in the Therapy of Various Types of Cancer

Cancer is among the most prominent causes of mortality worldwide. Different cancer therapy modes employed, including chemotherapy and radiotherapy, have been reported to be significant in cancer management, but the side effects associated with these treatment strategies are still a health problem. Therefore, alternative anticancer drugs based on medicinal plants or their active compounds have been generating attention because of their less serious side effects. Medicinal plants are an excellent source of phytochemicals that have been recognized to have health-prompting effects through modulating cell signaling pathways. Resveratrol is a well-known polyphenolic molecule with antioxidant, anti-inflammatory, and health-prompting effects among which its anticancer role has been best defined. Additionally, this polyphenol has confirmed its role in cancer management because it activates tumor suppressor genes, suppresses cell proliferation, induces apoptosis, inhibits angiogenesis, and modulates several other cell signaling molecules. The anticancer potential of resveratrol is recognized in numerous in vivo and in vitro studies. Previous experimental data suggested that resveratrol may be valuable in cancer management or improve the efficacy of drugs when given with anticancer drugs. This review emphasizes the potential role of resveratrol as an anticancer drug by modulating numerous cells signaling pathways in different types of cancer.

Molecular Basis of Resveratrol-Induced Resensitization of Acquired Drug-Resistant Cancer Cells

Multidrug resistance (MDR) to anticancer drugs remains a serious obstacle to the success of cancer chemotherapy. Resveratrol, a polyphenol, present in natural products exerts anticancer activity and acts as a potential MDR inhibitor in various drug-resistant cancer cells. In the process of resensitization of drug-resistant cancer cells, resveratrol has been shown to interfere with ABC transporters and drug-metabolizing enzymes, increase DNA damage, inhibit cell cycle progression, and induce apoptosis and autophagy, as well as prevent the induction of epithelial to mesenchymal transition (EMT) and cancer stem cells (CSCs). This review summarizes the mechanisms by which resveratrol counteracts MDR in acquired drug-resistant cancer cell lines and provides a critical basis for understanding the regulation of MDR as well as the development of MDR-inhibiting drugs.

The role of polyphenols in overcoming cancer drug resistance: a comprehensive review

Chemotherapeutic drugs are used to treat advanced stages of cancer or following surgery. However, cancers often develop resistance against drugs, leading to failure of treatment and recurrence of the disease. Polyphenols are a family of organic compounds with more than 10,000 members which have a three-membered flavan ring system in common. These natural compounds are known for their beneficial properties, such as free radical scavenging, decreasing oxidative stress, and modulating inflammation. Herein, we discuss the role of polyphenols (mainly curcumin, resveratrol, and epigallocatechin gallate [EGCG]) in different aspects of cancer drug resistance. Increasing drug uptake by tumor cells, decreasing drug metabolism by enzymes (e.g. cytochromes and glutathione-S-transferases), and reducing drug efflux are some of the mechanisms by which polyphenols increase the sensitivity of cancer cells to chemotherapeutic agents. Polyphenols also affect other targets for overcoming chemoresistance in cancer cells, including cell death (i.e. autophagy and apoptosis), EMT, ROS, DNA repair processes, cancer stem cells, and epigenetics (e.g. miRNAs).

The Yin and Yang dualistic features of autophagy in thermal burn wound healing

Burn healing should be regarded as a dynamic process consisting of two main, interrelated phases: (a) the inflammatory phase when neutrophils and monocytes infiltrate the injury site, through localized vasodilation and fluid extravasation, and (b) the proliferative-remodeling phase, which represents a key event in wound healing. In the skin, both canonical autophagy (induced by starvation, oxidative stress, and environmental aggressions) and non-canonical or selective autophagy have evolved to play a discrete, but, essential, “housekeeping” role, for homeostasis, immune tolerance, and survival. Experimental data supporting the pro-survival roles of autophagy, highlighting its Yang, luminous and positive feature of this complex but insufficient explored molecular pathway, have been reported. Autophagic cell death describes an “excessive” degradation of important cellular components that are necessary for normal cell function. This deadly molecular mechanism brings to light the darker, concealed, Yin feature of autophagy. Autophagy seems to perform dual, conflicting roles in the angiogenesis context, revealing once again, its Yin–Yang features. Autophagy with its Yin–Yang features remains the shadow player, able to decide quietly whether the cell survives or dies.

Canagliflozin, a SGLT-2 inhibitor, relieves ER stress, modulates autophagy and induces apoptosis in irradiated HepG2 cells: Signal transduction between PI3K/AKT/GSK-3β/mTOR and Wnt/β-catenin pathways; in vitro

Background and Objectives

Metabolic shifting from mitochondrial respiration to glycolysis characterizes malignant cells from its normal counterparts and is attributed to overactivation of oncogenic signaling pathways. Hence, this study intended to investigate the influence of canagliflozin (CAN) and/or γ-irradiation (γ-IR) on HepG2 cell proliferation, crosstalk between phosphatidylinositol 3-kinases (PI3K)/AKT/glycogen synthase kinase-3-β (GSK3-β)/mTOR and Wnt/β-catenin signaling pathways, and their regulation of diverse processes, such as endoplasmic reticulum (ER) stress, autophagy, and apoptosis.

Materials and Methods

HepG2 cells were treated with different doses of CAN and then exposed to different doses of γ-IR to achieve optimization that was based on cytotoxicity and clonogenic assays, respectively. The effects of CAN and/or γ-IR on glycolytic metabolism, cellular bioenergetics, oxidative stress, ER stress and autophagy biomarkers, expression of PI3K/AKT/GSK3-β/mTOR and Wnt/β-Catenin signaling pathways, and apoptotic markers were monitored.

Results

CAN enhanced the antitumor potential of γ-IR as displayed by a significant inhibition of clonogenic survival in HepG2 cells via inhibition of glucose uptake, lactate release, and modulation of ER stress-mediated autophagy; switched it to apoptosis; as well as disabled signaling pathways which contribute to metabolic reprogramming and tumor progression induced by γ-IR that confer radioresistance and treatment failure.

Conclusion

Our study sheds light on the effective combination of CAN and γ-IR in hepatocellular carcinoma treatment and necessitates CAN treatment prior to γ-IR to overcome metabolic reprogramming-associated radioresistance and improve curative outcomes.

Targeting AMPK Signaling by Dietary Polyphenols in Cancer Prevention

Cancer is a serious public health problem in the world and a major disease affecting human health. Dietary polyphenols have shown good potential in the treatment of various cancers. It is worth noting that cancer cells usually exhibit metabolic abnormalities of high glucose intake and inefficient utilization. AMPK is the key molecule in the regulation of energy metabolism and is closely related with obesity and diabetes. Recent studies indicate that AMPK also plays an important role in cancer prevention and regulating cancer-related genes and pathways, and dietary polyphenols can significantly regulate AMPK activity. In this review, the progress of dietary polyphenols preventing carcinogenesis via AMPK pathway is systemically summarized. From the viewpoint of interfering energy metabolism, the anti-cancer effects of dietary polyphenols are explained. AMPK pathway modulated by different dietary polyphenols affects pathways and target genes are summarized. Dietary polyphenols exert anti-cancer effect through the target molecules regulated by AMPK, which broadens the understanding of polyphenols anti-cancer mechanisms and provides value reference for the investigators of the novel field.

Polyphenols as Antitumor Agents Targeting Key Players in Cancer-Driving Signaling Pathways

Polyphenols constitute an important group of natural products that are traditionally associated with a wide range of bioactivities. These are usually found in low concentrations in natural products and are now available in nutraceuticals or dietary supplements. A group of polyphenols that include apigenin, quercetin, curcumin, resveratrol, EGCG, and kaempferol have been shown to regulate signaling pathways that are central for cancer development, progression, and metastasis. Here, we describe novel mechanistic insights on the effect of this group of polyphenols on key elements of the signaling pathways impacting cancer. We describe the protein modifications induced by these polyphenols and their effect on the central elements of several signaling pathways including PI3K, Akt, mTOR, RAS, and MAPK and particularly those affecting the tumor suppressor p53 protein. Modifications of p53 induced by these polyphenols regulate p53 gene expression and protein levels and posttranslational modifications such as phosphorylation, acetylation, and ubiquitination that influence stability, subcellular location, activation of new transcriptional targets, and the role of p53 in response to DNA damage, apoptosis control, cell- cycle regulation, senescence, and cell fate. Thus, deep understanding of the effects that polyphenols have on these key players in cancer-driving signaling pathways will certainly lead to better designed targeted therapies, with less toxicity for cancer treatment. The scope of this review centers on the regulation of key elements of cancer signaling pathways by the most studied polyphenols and highlights the importance of a profound understanding of these regulations in order to improve cancer treatment and control with natural products.

Induction of apoptosis in human hormone-refractory prostate cancer cell lines by using resveratrol in combination with AT-101

The aim of this study was to determine the appropriate doses of AT-101 and resveratrol combination in the in vitro hormone-refractory prostate cancer (PC) cell lines, in order to evaluate the cytotoxic and genotoxic effects of this combination on the proliferation of cancer cells, namely PC-3, DU-145 and LNCAP. Cytotoxicity in PC cell lines was analysed by using the XTT Cell Proliferation Assay. DNA damage was performed with the cell death assay. Apoptotic protein levels were performed by Roche Human Apoptosis Array. IC50 values were determined by XTT analysis. The strongest combined doses (100 µM resveratrol + 5µM AT-101) were found to have the strongest synergistic apoptotic and cytotoxic effects on DU-145 cells at 72 hr. While the combined use of resveratrol and AT-101 increased the expression of markers in apoptotic cell pathways on cells, a decrease in the expression of anti-apoptotic markers was detected (p ˂ 0.05). Combined applications of these compounds showed an important synergism in the hormone-refractory PC cell lines, and it was determined that after the post-translational modification, they were significantly effective on the apoptotic pathway. These results have revealed that the combination of resveratrol and AT-101 holds great expectation as a new chemotherapeutic application in the treatment of human prostate cancer.

Plant Polyphenols for Aging Health: Implication from Their Autophagy Modulating Properties in Age-Associated Diseases

Polyphenols are a family of naturally occurring organic compounds, majorly present in fruits, vegetables, and cereals, characterised by multiple phenol units, including flavonoids, tannic acid, and ellagitannin. Some well-known polyphenols include resveratrol, quercetin, curcumin, epigallocatechin gallate, catechin, hesperetin, cyanidin, procyanidin, caffeic acid, and genistein. They can modulate different pathways inside the host, thereby inducing various health benefits. Autophagy is a conserved process that maintains cellular homeostasis by clearing the damaged cellular components and balancing cellular survival and overall health. Polyphenols could maintain autophagic equilibrium, thereby providing various health benefits in mediating neuroprotection and exhibiting anticancer and antidiabetic properties. They could limit brain damage by dismantling misfolded proteins and dysfunctional mitochondria, thereby activating autophagy and eliciting neuroprotection. An anticarcinogenic mechanism is stimulated by modulating canonical and non-canonical signalling pathways. Polyphenols could also decrease insulin resistance and inhibit loss of pancreatic islet β-cell mass and function from inducing antidiabetic activity. Polyphenols are usually included in the diet and may not cause significant side effects that could be effectively used to prevent and treat major diseases and ailments.

Targeting of cancer cell death mechanisms by resveratrol: a review

Cancer cell death is the utmost aim in cancer therapy. Anti-cancer agents can induce apoptosis, mitotic catastrophe, senescence, or autophagy through the production of free radicals and induction of DNA damage. However, cancer cells can acquire some new properties to adapt to anti-cancer agents. An increase in the incidence of apoptosis, mitotic catastrophe, senescence, and necrosis is in favor of overcoming tumor resistance to therapy. Although an increase in the autophagy process may help the survival of cancer cells, some studies indicated that stimulation of autophagy cell death may be useful for cancer therapy. Using some low toxic agents to amplify cancer cell death is interesting for the eradication of clonogenic cancer cells. Resveratrol (a polyphenol agent) may affect various signaling pathways related to cell death. It can induce death signals and also downregulate the expression of anti-apoptotic genes. Resveratrol has also been shown to modulate autophagy and induce mitotic catastrophe and senescence in some cancer cells. This review focuses on the important targets and mechanisms for the modulation of cancer cell death by resveratrol.

Nitrate increases cisplatin chemosensitivity of oral squamous cell carcinoma via REDD1/AKT signaling pathway

Although cisplatin is one of the chemotherapeutics most frequently used in oral squamous cell carcinoma (OSCC) treatment, it exerts multiple side effects and poor chemosensitivity. Nitrate reportedly demonstrates several beneficial biological functions, and synthesized nitrates enhance the therapeutic efficacy of chemotherapy. However, the role of inorganic nitrate in cisplatin chemotherapy remains unclear. We therefore investigated the effect of inorganic nitrate exerted on cisplatin sensitivity in OSCC. We found that nitrate did not affect OSCC cell growth and apoptosis in OSCC cells and OSCC xenograft tumor animal studies. Cisplatin induced REDD1 expression and AKT activation in OSCC. However, nitrate could increase cisplatin chemosensitivity, reduce its REDD1 expression, and attenuate AKT signaling activation in OSCC cells. Dysregulation of high levels of REDD1, which could enhance AKT activation, was positively associated with poor prognosis in OSCC patients. Thus, reduced REDD1 expression and retarded AKT activation induced by inorganic nitrate might be a new potential approach to the sensitization of oral cancer to cisplatin treatment in the future.

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.

Dietary polyphenols in chemoprevention and synergistic effect in cancer: Clinical evidences and molecular mechanisms of action

BACKGROUND

Epidemiological studies has revealed that a diet rich in fruits and vegetables could lower the risk of certain cancers. In this setting, natural polyphenols are potent anticancer bioactive compounds to overcome the non-target specificity, undesirable cytotoxicity and high cost of treatment cancer chemotherapy.

PURPOSE

The review focuses on diverse classifications of the chemical diversity of dietary polyphenol and their molecular targets, modes of action, as well as preclinical and clinical applications in cancer prevention.

RESULTS

The dietary polyphenols exhibit chemo-preventive activity through modulation of apoptosis, autophagy, cell cycle progression, inflammation, invasion and metastasis. Polyphenols possess strong antioxidant activity and control multiple molecular events through activation of tumor suppressor genes and inhibition of oncogenes involved in carcinogenesis. Numerous in vitro and in vivo studies have evidenced that these dietary phytochemicals regulate critical molecular targets and pathways to limit cancer initiation and progression. Moreover, natural polyphenols act synergistically with existing clinically approved drugs. The improved anticancer activity of combinations of polyphenols and anticancer drugs represents a promising perspective for clinical applications against many human cancers.

CONCLUSION

The anticancer properties exhibited by dietary polyphenols are mainly attributed to their anti-metastatic, anti-proliferative, anti-angiogenic, anti-inflammatory, cell cycle arrest, apoptotic and autophagic effects. Hence, regular consumption of dietary polyphenols as food or food additives or adjuvants can be a promising tactic to preclude adjournment or cancer therapy.

Resveratrol-Based Nanoformulations as an Emerging Therapeutic Strategy for Cancer

Resveratrol is a polyphenolic stilbene derivative widely present in grapes and red wine. Broadly known for its antioxidant effects, numerous studies have also indicated that it exerts anti-inflammatory and antiaging abilities and a great potential in cancer therapy. Regrettably, the oral administration of resveratrol has pharmacokinetic and physicochemical limitations such as hampering its effects so that effective administration methods are demanding to ensure its efficiency. Thus, the present review explores the published data on the application of resveratrol nanoformulations in cancer therapy, with the use of different types of nanodelivery systems. Mechanisms of action with a potential use in cancer therapy, negative effects, and the influence of resveratrol nanoformulations in different types of cancer are also highlighted. Finally, the toxicological features of nanoresveratrol are also discussed.

In Vitro Toxicological Assessment of Gadodiamide in Normal Brain SVG P12 Cells

BACKGROUND/AIM

Magnetic resonance imaging (MRI) is a technique for evaluating patients with primary and metastatic tumors. The contrast agents improve the diagnostic accuracy of MRI. Large quantities of a contrast agent must be administrated into the patient to obtain useful images, which leads to cell injury. Gadolinium has been reported to cause central lobular necrosis of the liver and nephrogenic systemic fibrosis. However, the toxicity caused on brain tissue is uncertain.

MATERIALS AND METHODS

This study mainly aimed on the in vitro study of high concentration (2 and 5-fold of normal concentration) gadolinium-based contrast agents (GBCAs), gadodiamide (Omniscan^®), on normal brain glial SVG P12 cells. MTT assay, DAPI staining, immunofluorescent staining, LysoTracker Red staining, and western blotting analysis were applied on the cells.

RESULTS

The viability of gadodiamide (1.3, 2.6, 5.2, 13 and 26 mM)-treated SVG P12 cells was significantly reduced after 24 h of incubation. Gadodiamide caused significant autophagic flux at 2.6, 5.2 and 13.0 mM as seen by acridine orange (AO) staining, LC-3-GFP and LysoTracker Red staining. The expression levels of autophagy-related proteins such as beclin-1, ATG-5, ATG-14 and LC-3 II were up-regulated after 24 h of gadodiamide incubation. Autophagy inhibitors including 3-methyladenine (3-MA), chloroquine (CQ) and bafilomycin A1 (Baf) significantly alleviated the autophagic cell death effect of gadodiamide on normal brain glial SVG P12 cells. Gadodiamide induced significant apoptotic effects at 5.2 mM and 13.0 mM as seen by DAPI staining and the pan-caspase inhibitor significantly alleviated the apoptotic effect. Gadodiamide at 5.2 mM and 13.0 mM inhibited antiapoptotic protein expression levels of Bcl-2 and Bcl-XL, while promoted pro-apoptotic protein expression levels of Bax, BAD, cytochrome c, Apaf-1, cleaved-caspase-9 and cleaved-caspase-3.

CONCLUSION

Normal brain glial SVG P12 cells treated with high concentrations of gadodiamide can undergo autophagy and apoptosis.

Resveratrol effects in oral cancer cells: a comprehensive review

Oral cancer is a very common tumor worldwide with high incidence and mortality. The treatment of oral cancer involves surgery, radio- and chemotherapy; however, high failure rates and toxicity are noticed. Thus, the search of new drugs aiming a more effective treatment is welcomed. Natural products present chemopreventive and anti-cancer effects. Resveratrol is a naturally occurring antioxidant that contains several health benefits, including anti-inflammatory and antiproliferative activities. This review discusses the different action mechanisms of resveratrol related in the in vitro and in vivo studies using models of oral cancer.

Resveratrol, a Molecule with Anti-Inflammatory and Anti-Cancer Activities: Natural Product to Chemical Synthesis

BACKGROUND

Resveratrol, a natural polyphenol product, is used in plant defense from fungal and microbial aggression. It is found naturally, especially in plants such as grapes, peanuts, and berries. It has the highest concentrations in blueberries, mulberries, blackberries, and the skin of red grapes. Resveratrol has various pharmacological properties such as anti-inflammatory, cytoprotective, and antineoplastic activities.

METHODS

We conducted a literature survey using standard tools such as Google, Reaxys, Scifinder, Scihub, and patent Espacenet to compile the biosynthetic pathways, all organic synthetic methods, and biological activities reported for resveratrol till date.

RESULTS

More than one hundred research articles and patents were referred to write this review. About twenty-five of them are related to chemical synthesis, and the rests are about the source, pharmacological activity, and other properties of resveratrol. This study reveals that many common pathways are involved in various pharmacological activities, which can be useful for treating various diseases based on the pathways involved. Reactions such as Pfitzner-Moffatt oxidation, Wittig-Horner condensation, Mizoroki-Heck, Perkin, Wittig, etc. have been used in resveratrol synthesis. A structure-activity relationship was also established based on its analogs and derivatives.

CONCLUSION

This review examined and reported all the published biological activities and chemical syntheses of resveratrol apart from the biosynthetic pathway. Due to its valuable biological activities, various synthetic approaches have been reported till date. The reported synthetic operations are suitable for large-scale industrial production. Moreover, these comprehensive synthetic procedures could be utilized in the preparation of stilbenes and other related compounds in future endeavors.

Chemopreventive and Anti-tumor Potential of Natural Products in Oral Cancer

Oral cancer (OC) is a multifactorial disease caused by isolated or combined risk factors related to tobacco, alcohol consumption, and human papillomavirus infection. It is an aggressive pathology with a low five-year survival rate after surgery, chemotherapy, and/or radiotherapy, frequently associated with severe side effects. Drugs with the highest anti-tumor effect are obtained from natural products with diverse biological and molecular activities and potential chemopreventive and anticancer properties. This review summarizes the natural products reported to have the chemopreventive and anti-tumor potential for OC treatment, showing that several of these compounds are promising candidates as chemopreventive agents, and those with the highest anti-tumor potential induce apoptosis and inhibit proliferation and metastasis-related processes. For this reason, natural products have the potential to be important preventive and therapeutic options for OC in the future.

Resveratrol induces AMPK and mTOR signaling inhibition-mediated autophagy and apoptosis in multiple myeloma cells

Resveratrol, a natural compound extracted from the skins of grapes, berries, or other fruits, has been shown to have anti-tumor effects against multiple myeloma (MM) via promoting apoptosis and inhibiting cell viability. In addition to apoptosis, autophagy also plays a significant role in anti-tumor effects. However, whether autophagy is involved in anti-MM activity of resveratrol remains unclear. In this study, human MM cell lines U266, RPMI-8226, and NCI-H929 were treated with resveratrol. Cell Counting Kit-8 assay and colony formation assay were used to measure cell viability. Western blot analysis was used to detect apoptosis- and autophagy-associated proteins. 3-Methyladenine (3-MA) was applied to inhibit autophagy. Results showed that resveratrol inhibited cell viability and colony formation via promoting apoptosis and autophagy in MM cell lines U266, RPMI-8226, and NCI-H929. Resveratrol promoted apoptosis-related proteins, Caspase-3 activating poly-ADP-ribose polymerase and Caspase-3 cleavage, and decreased the protein level of Survivin in a dose-dependent manner. Additionally, resveratrol upregulated the levels of LC3 and Beclin1 in a dose-dependent way, indicating that autophagy might be implicated in anti-MM effect of resveratrol. Furthermore, 3-MA relieved the cytotoxicity of resveratrol by blocking the autophagic flux. Resveratrol increased the phosphorylation of adenosine monophosphate (AMP)-activated protein kinase and decreased the phosphorylation of mammalian target of rapamycin (mTOR) and its downstream substrates p70S6K and 4EBP1 in a dose-dependent manner, leading to autophagy. Therefore, our results suggest that resveratrol exerts anti-MM effects through apoptosis and autophagy, which can be used as a new therapeutic strategy for MM in clinic.

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.