Emodin augments cisplatin cytotoxicity in platinum-resistant ovarian cancer cells via ROS-dependent MRP1 downregulation

Natural products for enhancing the sensitivity or decreasing the adverse effects of anticancer drugs through regulating the redox balance

Redox imbalance is reported to play a pivotal role in tumorigenesis, cancer development, and drug resistance. Severe oxidative damage is a general consequence of cancer cell responses to treatment and may cause cancer cell death or severe adverse effects. To maintain their longevity, cancer cells can rescue redox balance and enter a state of resistance to anticancer drugs. Therefore, targeting redox signalling pathways has emerged as an attractive and prospective strategy for enhancing the efficacy of anticancer drugs and decreasing their adverse effects. Over the past few decades, natural products (NPs) have become an invaluable source for developing new anticancer drugs due to their high efficacy and low toxicity. Increasing evidence has demonstrated that many NPs exhibit remarkable antitumour effects, whether used alone or as adjuvants, and are emerging as effective approaches to enhance sensitivity and decrease the adverse effects of conventional cancer therapies by regulating redox balance. Among them are several novel anticancer drugs based on NPs that have entered clinical trials. In this review, we summarize the synergistic anticancer effects and related redox mechanisms of the combination of NPs with conventional anticancer drugs. We believe that NPs targeting redox regulation will represent promising novel candidates and provide prospects for cancer treatment in the future.

Research Progress of Plant-Derived Natural Products against Drug-Resistant Cancer

As one of the malignant diseases globally, cancer seriously endangers human physical and mental health because of its high morbidity and mortality. Conventional cancer treatment strategies, such as surgical resection and chemoradiotherapy, are effective at the early stage of cancer but have limited efficacy for advanced cancer. Along with cancer progress and treatment, resistance develops gradually within the population of tumor cells. As a consequence, drug resistance become the major cause that leads to disease progression and poor clinical prognosis in some patients. The mechanisms of cancer drug resistance are quite complex and involve various molecular and cellular mechanisms. Therefore, exploring the mechanisms and finding specific targets are becoming imperative to overcome drug resistance. In recent years, plant-derived natural products have been evaluated as potential therapeutic candidates against cancer with drug resistance due to low side effects and high anticancer efficacy. A growing number of studies have shown that natural products can achieve superior antitumor effects through multiple signaling pathways. The mechanisms include regulation of multiple drug resistance (MDR)-related genes, inhibition of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway, induction of autophagy, and blockade of the cell cycle. This paper reviews the molecular and cellular mechanisms of cancer drug resistance, as well as the therapeutic effects and mechanisms of plant-derived natural products against cancer drug resistance. It provides references for developing therapeutic medication for drug-resistant cancer treatment with high efficacy and low side effects.

A Review on Bioactive Anthraquinone and Derivatives as the Regulators for ROS

Anthraquinones are bioactive natural products, which are often found in medicinal herbs. These compounds exert antioxidant-related pharmacological actions including neuroprotective effects, anti-inflammation, anticancer, hepatoprotective effects and anti-aging, etc. Considering the benefits from their pharmacological use, recently, there was an upsurge in the development and utilization of anthraquinones as reactive oxygen species (ROS) regulators. In this review, a deep discussion was carried out on their antioxidant activities and the structure-activity relationships. The antioxidant mechanisms and the chemistry behind the antioxidant activities of both natural and synthesized compounds were furtherly explored and demonstrated. Due to the specific chemical activity of ROS, antioxidants are essential for human health. Therefore, the development of reagents that regulate the imbalance between ROS formation and elimination should be more extensive and rational, and the exploration of antioxidant mechanisms of anthraquinones may provide new therapeutic tools and ideas for various diseases mediated by ROS.

Could alder buckthorn (Frangula alnus Mill) be a source of chemotherapeutics effective against hepato- and colorectal carcinoma? An in vitro study

Among numerous types of cancer, hepatocellular and colorectal carcinoma are important causes of mortality. Given the nature of these cancer types and their resistance, it is of great importance to find new chemotherapeutics and therapy targets, so plant products seem to be an excellent choice in such search. The main goal of this study was to investigate anticancer activity of Frangula alnus ethyl-acetate extract (FA) and its dominant constituent emodin (E) on hepatocellular and colorectal carcinoma cell lines, HepG2 and HCT116, as well as on normal MRC-5 fibroblasts. Cytotoxicity was investigated in MTT test and both FA and E showed strong reduction of cell viability in cancer cells. Flow cytometer analysis demonstrated that FA and E led to G1 phase arrest and slight accumulation of cells in the G2/M phase; additionally, annexinV-FITC/7AAD dying showed that FA and E decreased cell viability and triggered apoptosis in all cell lines. FA and E evidenced strong genotoxic potential in comet assay performed on all cell lines, while tests measuring antioxidative potential (DPPH and TBA) demonstrated strong effect of FA. It could be concluded that both FA and E have significant anticancer activity against hepatocellular and colorectal carcinoma cell lines HepG2 and HCT116, but notable selectivity was not observed.

Cisplatin in Ovarian Cancer Treatment-Known Limitations in Therapy Force New Solutions

Cisplatin is one of the most commonly used anticancer drugs worldwide. It is mainly used in the treatment of ovarian cancer, but also used in testicular, bladder and lung cancers. The significant advantage of this drug is the multidirectional mechanism of its anticancer action, with the most important direction being damaging the DNA of cancer cells. Unfortunately, cisplatin displays a number of serious disadvantages, including toxicity to the most important organs, such as kidneys, heart, liver and inner ear. Moreover, a significant problem among patients with ovarian cancer, treated with cisplatin, is the development of numerous resistance mechanisms during therapy, including changes in the processes of cellular drug import and export, changes in the DNA damage repair mechanisms, as well as numerous changes in the processes of apoptosis and autophagy. Due to all of the mentioned problems, strategies to increase the effectiveness of cisplatin in the treatment of ovarian cancer are intensively sought. The most important strategy includes the development of less toxic cisplatin analogs. Another important direction is combination therapy, involving the simultaneous use of cisplatin with different anticancer drugs, substances derived from plants, temperature or radiotherapy. Many years of observations accompanying the presence of cisplatin in the therapy made it possible to provide a series of verifiable, statistically significant data, but also to show how, over time, with the new information and scientific discoveries, it is possible to describe and understand the therapeutic problems observed in practice, such as the acquisition of drug resistance by tumor cells or induction of changes in the tumor microenvironment. According to the authors, confronting what we knew so far with what new trends offer has a profound meaning. This paper presents information on the history of cisplatin and describes the molecular mechanisms of its action and the development of resistance by cancer cells. In addition, our goal was to highlight a number of therapeutic strategies to increase the effectiveness of cisplatin in the treatment of ovarian cancer, as well as to identify methods to eliminate problems associated with the use of cisplatin.

Therapeutically important bioactive compounds of the genus Polygonum L. and their possible interventions in clinical medicine

OBJECTIVES

Increasing literature data have suggested that the genus Polygonum L. possesses pharmacologically important plant secondary metabolites. These bioactive compounds are implicated as effective agents in preclinical and clinical practice due to their pharmacological effects such as anti-inflammatory, anticancer, antidiabetic, antiaging, neuroprotective or immunomodulatory properties among many others. However, elaborate pharmacological and clinical data concerning the bioavailability, tissue distribution pattern, dosage and pharmacokinetic profiles of these compounds are still scanty.

KEY FINDINGS

The major bioactive compounds implicated in the therapeutic effects of Polygonum genus include phenolic and flavonoid compounds, anthraquinones and stilbenes, such as quercetin, resveratrol, polydatin and others, and could serve as potential drug leads or as adjuvant agents. Data from in-silico network pharmacology and computational molecular docking studies are also highly helpful in identifying the possible drug target of pathogens or host cell machinery.

SUMMARY

We provide an up-to-date overview of the data from pharmacodynamic, pharmacokinetic profiles and preclinical (in-vitro and in-vivo) investigations and the available clinical data on some of the therapeutically important compounds of genus Polygonum L. and their medical interventions, including combating the outbreak of the COVID-19 pandemic.

Effect of thread depth and thread pitch on the primary stability of miniscrews receiving a torque load : A finite element analysis

PURPOSE

We have been developing a new type of miniscrew to specifically withstand orthodontic torque load. This study aimed to investigate the effect of thread depth and thread pitch on the primary stability of these miniscrews if stressed with torque load.

METHODS

Finite element analysis (FEA) was used to evaluate the primary stability of the miniscrews. For thread depth analysis, the thread depth was set to 0.1-0.4 mm to construct 7 models. For thread pitch analysis, the thread pitch was set to 0.4-1.0 mm to construct another 7 models. A torque load of 6 Nmm was applied to the miniscrew, and the other parameters were kept constant for the analyses. Maximum equivalent stress (Max EQV) of cortical bone and maximum displacement of the miniscrews (Max DM) were the indicators for primary stability of the miniscrew in the 14 models.

RESULTS

In the thread depth analysis, Max DM increased as the miniscrew thread depth increased, while Max EQV was smallest in model 3 (thread depth = 0.2, Max EQV = 8.91 MPa). In the pitch analysis, with an increase of the thread pitch, Max DM generally exhibited a trend to increase, while Max EQV of cortical bone showed a general trend to decrease.

CONCLUSION

Considering the data of Max DM and Max EQV, the most appropriate thread depth and thread pitch of the miniscrews in our model was 0.2 and 0.7 mm, respectively. This knowledge may effectively improve the primary stability of newly developed miniscrews.

Characterizing breast masses using an integrative framework of machine learning and CEUS-based radiomics

AIMS

We evaluated the performance of contrast-enhanced ultrasound (CEUS) based on radiomics analysis to distinguish benign from malignant breast masses.

METHODS

131 women with suspicious breast masses (BI-RADS 4a, 4b, or 4c) who underwent CEUS examinations (using intravenous injection of perflutren lipid microsphere or sulfur hexafluoride lipid-type A microspheres) prior to ultrasound-guided biopsies were retrospectively identified. Post biopsy pathology showed 115 benign and 16 malignant masses. From the cine clip of the CEUS exams obtained using the built-in GE scanner software, breast masses and adjacent normal tissue were then manually segmented using the ImageJ software. One frame representing each of the four phases: precontrast, early, peak, and delay enhancement were selected post segmentation from each CEUS clip. 112 radiomic metrics were extracted from each segmented tissue normalized breast mass using custom Matlab® code. Linear and nonlinear machine learning (ML) methods were used to build the prediction model to distinguish benign from malignant masses. tenfold cross-validation evaluated model performance. Area under the curve (AUC) was used to quantify prediction accuracy.

RESULTS

Univariate analysis found 35 (38.5%) radiomic variables with p < 0.05 in differentiating between benign from malignant masses. No feature selection was performed. Predictive models based on AdaBoost reported an AUC = 0.72 95% CI (0.56, 0.89), followed by Random Forest with an AUC = 0.71 95% CI (0.56, 0.87).

CONCLUSIONS

CEUS based texture metrics can distinguish between benign and malignant breast masses, which can, in turn, lead to reduced unnecessary breast biopsies.

Sporoderm-Broken Spores of Ganoderma lucidum Sensitizes Ovarian Cancer to Cisplatin by ROS/ERK Signaling and Attenuates Chemotherapy-Related Toxicity

Although platinum-based chemotherapeutics such as cisplatin are the cornerstone of treatment for ovarian cancer, their clinical application is profoundly limited due to chemoresistance and severe adverse effects. Sporoderm-broken spores of Ganoderma lucidum (SBSGL) have been reported to possess antitumor effects. However, the function and mechanism of SBSGL and its essential composition, ganoderic acid D (GAD), in the cisplatin therapy on ovarian cancer have yet to be investigated. Here, we investigated the combined effect of SBSGL and cisplatin in an ovarian tumor xenograft model. The results showed that combining SBSGL with cisplatin reduced tumor growth and ameliorated cisplatin-induced intestinal injury and myelosuppression. We also confirmed that GAD could enhance the therapeutic effect of cisplatin in SKOV3 and cisplatin-resistant SKOV3/DDP cells by increasing the intracellular reactive oxygen species (ROS). Mechanistically, we proved that ROS-mediated ERK signaling inhibition played an important role in the chemo-sensitization effect of GAD on cisplatin in ovarian cancer. Taken together, combining SBSGL with cisplatin provides a novel therapeutic strategy against ovarian cancer.

Converting sounds to meaning with ventral semantic language networks: integration of interdisciplinary data on brain connectivity, direct electrical stimulation and clinical disconnection syndromes

Numerous traditional linguistic theories propose that semantic language pathways convert sounds to meaningful concepts, generating interpretations ranging from simple object descriptions to communicating complex, analytical thinking. Although the dual-stream model of Hickok and Poeppel is widely employed, proposing a dorsal stream, mapping speech sounds to articulatory/phonological networks, and a ventral stream, mapping speech sounds to semantic representations, other language models have been proposed. Indeed, despite seemingly congruent models of semantic language pathways, research outputs from varied specialisms contain only partially congruent data, secondary to the diversity of applied disciplines, ranging from fibre dissection, tract tracing, and functional neuroimaging to neuropsychiatry, stroke neurology, and intraoperative direct electrical stimulation. The current review presents a comprehensive, interdisciplinary synthesis of the ventral, semantic connectivity pathways consisting of the uncinate, middle longitudinal, inferior longitudinal, and inferior fronto-occipital fasciculi, with special reference to areas of controversies or consensus. This is achieved by describing, for each tract, historical concept evolution, terminations, lateralisation, and segmentation models. Clinical implications are presented in three forms: (a) functional considerations derived from normal subject investigations, (b) outputs of direct electrical stimulation during awake brain surgery, and (c) results of disconnection syndromes following disease-related lesioning. The current review unifies interpretation of related specialisms and serves as a framework/thinking model for additional research on language data acquisition and integration.

Alpinetin: A Review of Its Pharmacology and Pharmacokinetics

Flavonoids isolated from medicinal herbs have been utilized as valuable health-care agents due to their virous biological applications. Alpinetin is a natural flavonoid that emerges in many widely used medicinal plants, and has been frequently applied in Chinese patent drugs. Accumulated evidence has demonstrated that alpinetin possesses a broad range of pharmacological activities such as antitumor, antiinflammation, hepatoprotective, cardiovascular protective, lung protective, antibacterial, antiviral, neuroprotective, and other properties through regulating multiple signaling pathways with low systemic toxicity. However, pharmacokinetic studies have documented that alpinetin may have poor oral bioavailability correlated to its extensive glucuronidation. Currently, the reported pharmacological properties and pharmacokinetics profiles of alpinetin are rare to be scientifically reviewed. In this article, we aimed to highlight the mechanisms of action of alpinetin in various diseases to strongly support its curative potentials for prospective clinical applications. We also summarized the pharmacokinetics properties and proposed some viable strategies to convey an appreciable reference for future advances of alpinetin in drug development.

Is Emodin with Anticancer Effects Completely Innocent? Two Sides of the Coin

Many anticancer active compounds are known to have the capacity to destroy pathologically proliferating cancer cells in the body, as well as to destroy rapidly proliferating normal cells. Despite remarkable advances in cancer research over the past few decades, the inclusion of natural compounds in researches as potential drug candidates is becoming increasingly important. However, the perception that the natural is reliable is an issue that needs to be clarified. Among the various chemical classes of natural products, anthraquinones have many biological activities and have also been proven to exhibit a unique anticancer activity. Emodin, an anthraquinone derivative, is a natural compound found in the roots and rhizomes of many plants. The anticancer property of emodin, a broad-spectrum inhibitory agent of cancer cells, has been detailed in many biological pathways. In cancer cells, these molecular mechanisms consist of suppressing cell growth and proliferation through the attenuation of oncogenic growth signaling, such as protein kinase B (AKT), mitogen-activated protein kinase (MAPK), HER-2 tyrosine kinase, Wnt/-catenin, and phosphatidylinositol 3-kinase (PI3K). However, it is known that emodin, which shows toxicity to cancer cells, may cause kidney toxicity, hepatotoxicity, and reproductive toxicity especially at high doses and long-term use. At the same time, studies of emodin, which has poor oral bioavailability, to transform this disadvantage into an advantage with nano-carrier systems reveal that natural compounds are not always directly usable compounds. Consequently, this review aimed to shed light on the anti-proliferative and anti-carcinogenic properties of emodin, as well as its potential toxicities and the advantages of drug delivery systems on bioavailability.

Molecular mechanisms and cardiovascular implications of cancer therapy-induced senescence

Cancer treatment has been associated with accelerated aging that can lead to early-onset health complications typically experienced by older populations. In particular, cancer survivors have an increased risk of developing premature cardiovascular complications. In the last two decades, cellular senescence has been proposed as an important mechanism of premature cardiovascular diseases. Cancer treatments, specifically anthracyclines and radiation, have been shown to induce senescence in different types of cardiovascular cells. Additionally, clinical studies identified increased systemic markers of senescence in cancer survivors. Preclinical research has demonstrated the potential of several approaches to mitigate cancer therapy-induced senescence. However, strategies to prevent and/or treat therapy-induced cardiovascular senescence have not yet been translated to the clinic. In this review, we will discuss how therapy-induced senescence can contribute to cardiovascular complications. Thereafter, we will summarize the current in vitro, in vivo, and clinical evidence regarding cancer therapy-induced cardiovascular senescence. Then, we will discuss interventional strategies that have the potential to protect against therapy-induced cardiovascular senescence. To conclude, we will highlight challenges and future research directions to mitigate therapy-induced cardiovascular senescence in cancer survivors.

Elucidating Role of Reactive Oxygen Species (ROS) in Cisplatin Chemotherapy: A Focus on Molecular Pathways and Possible Therapeutic Strategies

The failure of chemotherapy is a major challenge nowadays, and in order to ensure effective treatment of cancer patients, it is of great importance to reveal the molecular pathways and mechanisms involved in chemoresistance. Cisplatin (CP) is a platinum-containing drug with anti-tumor activity against different cancers in both pre-clinical and clinical studies. However, drug resistance has restricted its potential in the treatment of cancer patients. CP can promote levels of free radicals, particularly reactive oxygen species (ROS) to induce cell death. Due to the double-edged sword role of ROS in cancer as a pro-survival or pro-death mechanism, ROS can result in CP resistance. In the present review, association of ROS with CP sensitivity/resistance is discussed, and in particular, how molecular pathways, both upstream and downstream targets, can affect the response of cancer cells to CP chemotherapy. Furthermore, anti-tumor compounds, such as curcumin, emodin, chloroquine that regulate ROS and related molecular pathways in increasing CP sensitivity are described. Nanoparticles can provide co-delivery of CP with anti-tumor agents and by mediating photodynamic therapy, and induce ROS overgeneration to trigger CP sensitivity. Genetic tools, such as small interfering RNA (siRNA) can down-regulate molecular pathways such as HIF-1α and Nrf2 to promote ROS levels, leading to CP sensitivity. Considering the relationship between ROS and CP chemotherapy, and translating these findings to clinic can pave the way for effective treatment of cancer patients.

Polygalacin D suppresses esophageal squamous cell carcinoma growth and metastasis through regulating miR-142-5p/Nrf2 axis

Esophageal squamous cell carcinoma (ESCC) is a common malignancy worldwide with poor survival. High expression of nuclear factor erythroid 2-related factor 2 (Nrf2) is an antioxidant transcript factor that protects malignant cells from death. Polygalacin D (PGD), a bioactive compound isolated from Platycodongrandiflorum (Jacq.), has recently been reported to be an anti-tumor agent. This study aimed to investigate the anti-cancer effects of PGD and its underlying molecular mechanisms in human ESCC. Here, we confirmed that Nrf2 was over-expressed in clinical ESCC tissues and cell lines. PGD treatments markedly reduced Nrf2 expression in a dose- and time-dependent manner in ESCC cell lines. Importantly, we found that PGD significantly reduced proliferation, and induced G2/M cell cycle arrest and apoptosis in ESCC cells. Also, PGD dramatically triggered autophagy in ESCC cells, and autophagy inhibitor bafilomycinA1 (BafA1) greatly abrogated the inhibitory role of PGD in cell viability and apoptosis. In addition, PGD evidently provoked reactive oxygen species (ROS) accumulation in ESCC cells, and pre-treatment of ROS scavenger N-acetyl-l-cysteine (NAC) markedly abolished PGD-triggered cell death. PGD also dramatically repressed migration and invasion in ESCC cells. Mechanistic investigation revealed that Nrf2 gene was directly targeted by miR-142-5p. MiR-142-5p negatively regulated Nrf2 expression in ESCC cells. We notably found that PGD-inhibited proliferation, migration and invasion in ESCC were considerably rescued by miR-142-5p knockdown; however, ROS production, apoptosis and autophagy induced by PGD were almost eliminated when miR-142-5p was silenced. On the contrast, over-expressing miR-142-5p could remarkably promote the anti-ESCC effects of PGD. Experiments in vivo by the tumor xenograft model confirmed that miR-142-5p effectively improved the activity of PGD to repress tumor growth and lung metastasis. Both in vitro and in vivo studies showed that PGD had few side effects on normal cells and major organs. Collectively, our findings provided the first evidence that PGD could be an effective therapeutic strategy for ESCC treatment by regulating miR-142-5p/Nrf2 axis with few adverse effects.

Emodin Induced Necroptosis and Inhibited Glycolysis in the Renal Cancer Cells by Enhancing ROS

Renal cell carcinoma (RCC) is a tumor with unpredictable presentation and poor clinical outcome. RCC is always resistant to chemotherapy and radiation, and weakly sensitive to immunotherapeutic agents. Therefore, novel agents and approaches are urgently needed for the treatment of RCC. Emodin, an anthraquinone compound extracted from rhubarb and other traditional Chinese herbs, has been implicated in a wide variety of pharmacological effects, such as anti-inflammatory, antiviral, and antitumor activities. However, its role in RCC remains unknown. In this study, we found that emodin effectively killed renal cancer cells without significant toxicity to noncancerous cell HK-2. Flow cytometry assay with Annexin V-FITC and PI demonstrated that emodin induces necroptosis, but not apoptosis, in renal cancer cells. Meanwhile, the phosphorylation levels of RIP1 and MLKL, the key necroptosis-related proteins, were significantly increased. To explore how emodin inhibits kidney tumor growth, we tested reactive oxygen species (ROS) levels and found that the levels of ROS increased upon emodin treatment in a dose-dependent manner. Further studies demonstrated that emodin induces necroptosis through ROS-mediated activation of JNK signaling pathway and also inhibits glycolysis by downregulation of GLUT1 through ROS-mediated inactivation of the PI3K/AKT signaling pathway. Our findings revealed the potential mechanisms by which emodin suppresses renal cancer cell growth and will help develop novel therapeutic approaches for patients with JNK- or PI3K/AKT-dysregulated renal cancer.

Amplification of oxidative stress via intracellular ROS production and antioxidant consumption by two natural drug-encapsulated nanoagents for efficient anticancer therapy

Cancer cells are commonly characterized by high cellular oxidative stress and thus have poor tolerance to oxidative insults. In this study, we developed a nano-formulation to elevate the level of reactive oxygen species (ROS) in cancer cells via promoting ROS production as well as weakening cellular anti-oxidizing systems. The nanoagent was fabricated by encapsulating two natural product molecules, cinnamaldehyde (CA) and diallyl trisulfide (DATS), in PLGA-PEG copolymer formulated nanoparticles. CA promotes ROS generation in cancer cells and DATS depletes cellular glutathione. CA and DATS exhibited a synergistic effect in amplifying the ROS levels in cancer cells and further in their combined killing of cancer cells. The in vivo experiments revealed that the CA and DATS-encapsulated nanoagent suppressed tumors more efficiently as compared with the single drug-loaded ones, and the tumor-targeted delivery further enhanced the therapeutic efficacy. This study suggests that the combined enhancement of oxidative stress by CA and DATS could be a promising strategy for cancer therapy.

Plumbagin Enhances the Anticancer Efficacy of Cisplatin by Increasing Intracellular ROS in Human Tongue Squamous Cell Carcinoma

Cisplatin is widely used in the treatment of tongue squamous cell carcinoma (TSCC), but its clinical efficacy is limited by drug resistance and toxic side effects. Hence, a novel compound capable of enhancing the anticancer effect of cisplatin while reducing the side effects is urgently needed. We have previously shown that plumbagin (PLB), an anticancer phytochemical, is able to inhibit the growth of TSCC in vitro and in vivo. The objective of this study was to investigate the effect of PLB in reversing the resistance of TSCC to cisplatin as well as its molecular mechanisms. Here, we found that PLB enhances cisplatin-induced cytotoxicity, apoptosis, and autophagy in CAL27 and cisplatin-resistant CAL27/CDDP cells. PLB could inhibit the viability and growth of TSCC cells by increasing the production of intracellular reactive oxygen species (ROS). In addition, the combination treatment of PLB and cisplatin resulted in a synergistic inhibition of TSCC viability, apoptosis, and autophagy by increasing intracellular ROS, which may be achieved by activating JNK and inhibiting AKT/mTOR signaling pathways. Finally, the synergistic treatment was also demonstrated in vivo. Therefore, PLB combined with cisplatin is a potential therapeutic strategy against therapy TSCC cisplatin resistance.

Knockdown of long non-coding RNA LINC00152 increases cisplatin sensitivity in ovarian cancer cells

Drug resistance severely limits the effectiveness of chemotherapeutic treatment in ovarian cancer. The present study aimed to investigate the role of long non-coding RNA LINC00152 (LINC00152) in the cisplatin resistance of ovarian cancer. The expression level of LINC00152 was significantly increased in the ovarian cancer CoC1 and CoC1/DDP cell lines compared with the normal ovarian IOSE-80 cell line. To further investigate the function of LINC00152, small interfering RNAs (siRNAs) targeting LINC00152 were transfected into COC1 and COC1/DDP cells, which were subsequently treated with varying concentrations of cisplatin. The results revealed that LINC00152 silencing increased the apoptotic rates and enhanced the chemosensitivity of CoC1 and CoC1/DDP cells to cisplatin. Furthermore, downregulation of LINC00152 significantly decreased Bcl-2, and increased Bax and cleaved caspase-3 expression levels. Additionally, LINC00152 silencing decreased the expression of multidrug resistance-associated gene 1 (MDR1), multidrug resistance-associated protein 1 (MRP1) and glutathione S-transferase π (GSTπ). Collectively, the data demonstrated that LINC00152 knockdown increased the chemosensitivity of epithelial ovarian cancer cells to cisplatin by increasing apoptosis and decreasing the expression levels of MDR1, MRP1 and GSTπ.

Anthraquinones and autophagy - Three rings to rule them all?

In order to overcome therapy resistance in cancer, scientists search in nature for novel lead structures for the development of improved chemotherapeutics. Anthraquinones belong to a class of tricyclic organic natural compounds with promising anti-cancer effects. Anthraquinone derivatives are rich in structural diversity, and exhibit pleiotropic properties, among which the modulation of autophagy seems promising in the context of overcoming cancer-therapy resistance. Among the most promising derivatives in this regard are emodin, aloe emodin, rhein, physcion, chrysophanol and altersolanol A. On the molecular level, these compounds target autophagy via different upstream pathways including the AKT/mTOR-axis and transcription of autophagy-related proteins. The role of autophagy is pro-survival as well as cell death-promoting, depending on derivatives and their cell type specificity. This review summarizes observed effects of anthraquinone derivatives on autophagy and discusses targeted pathways and crosstalks. A cumulative knowledge about this topic paves the way for further research on modes of action, and aids to find a therapeutic window of anthraquinones in cancer-therapy.

Emodin Induced SREBP1-Dependent and SREBP1-Independent Apoptosis in Hepatocellular Carcinoma Cells

Reynoutria multiflora (Thunb.) Moldenke (He Shou Wu) has been used for about 20 centuries as a Chinese medicinal herb for its activities of anticancer, anti-hyperlipidemia, and anti-aging. Previously, we found that He Shou Wu ethanol extract could induce apoptosis in hepatocellular carcinoma cells, and we also screened its active components. In this study, we investigated whether lowering lipid metabolism of emodin, a main active component in He Shou Wu, was associated with inhibitory effects in hepatocellular carcinoma cells. The correlation of apoptosis induction and lipid metabolism was investigated. The intrinsic apoptotic cell death, lipid production, and their signaling pathways were investigated in emodin-treated human hepatocellular carcinoma cells Bel-7402. The data showed that emodin triggered apoptosis in Bel-7402 cells. The mitochondrial membrane potential (ΔΨm) was reduced in emodin-treated Bel-7402 cells. We also found that emodin activated the expression of intrinsic apoptosis signaling pathway-related proteins, cleaved-caspase 9 and 3, Apaf 1, cytochrome c (CYTC), apoptosis-inducing factor, endonuclease G, Bax, and Bcl-2. Furthermore, the level of triglycerides and desaturation of fatty acids was reduced in Bel-7402 cells when exposed to emodin. Furthermore, the expression level of messenger RNA (mRNA) and protein of sterol regulatory element binding protein 1 (SREBP1) as well as its downstream signaling pathway and the synthesis and the desaturation of fatty acid metabolism-associated proteins (adenosine triphosphate citrate lyase, acetyl-CoA carboxylase alpha, fatty acid synthase (FASN), and stearoyl-CoA desaturase D) were also decreased. Notably, knock-out of SREBP1 in Bel-7402 cells was also found to induce less intrinsic apoptosis than did emodin. In conclusion, these results indicated that emodin could induce apoptosis in an SREBP1-dependent and SREBP1-independent manner in hepatocellular carcinoma cells.

Emodin, a natural anthraquinone, suppresses liver cancer in vitro and in vivo by regulating VEGFR2 and miR-34a

The pharmacokinetic (PK) and potential effects of Emodin on liver cancer were systematically evaluated in this study. Both the intragastric administration (i.g.) and hypodermic injection (i.h.) of Emodin exhibited a strong absorption (absorption rate < 1 h) and elimination capacity (t_1/2 ≈ 2 h). The tissue distribution of Emodin after i.h. was rapid and wide. The stability of Emodin in three species of liver microsomes wasrat >human> beagle dog. These PK data provided the basis for the subsequent animal experiments. In liver cancer patient tissues, the expression of vascular endothelial growth factor (VEGF)-induced signaling pathways, including phosphorylated VEGF receptor 2 (VEGFR₂), AKT, and ERK_1/2,were simultaneously elevated, but miR-34a expression was reduced and negatively correlated with SMAD₂ and SMAD₄. Emodin inhibited the expression of SMAD_2/4 in HepG2 cells by inducing the miR-34a level. Subsequently, BALB/c nude mice received a daily subcutaneous injection of HepG2 cells with or without Emodin treatment (1 mg/kg or 10 mg/kg), and Emodin inhibited tumorigenesis and reduced the mortality rate in a dose-dependent manner. In vivo experiments showed that cell proliferation, migration, and invasion were promoted by VEGF or miR-34a signal treatment but were inhibited when combined with Emodin treatment. All these results demonstrated that Emodin inhibited tumorigenesis in liver cancer by simultaneously inhibiting the VEGFR₂-AKT-ERK_1/2signaling pathway and promoting a miR-34a-mediated signaling pathway.

Dietary phytochemicals with anti-oxidant and pro-oxidant activities: A double-edged sword in relation to adjuvant chemotherapy and radiotherapy?

Many advances have been made in the development and introduction of new anti-cancer drugs to the clinic. However, limited attention has been paid to improving the efficacy of currently available treatments through complementary phytochemical interventions that affect cellular reactive oxygen species (ROS) levels, which are important for the etiology of certain cancers and the effectiveness of radiotherapy and some chemotherapy. In this regard, the maintenance of redox homeostasis may be influenced by the intake of anti-oxidant and pro-oxidant compounds from dietary sources. Interestingly, certain dietary phytochemicals exhibit both anti-oxidant and pro-oxidant activities, depending on their concentration and cellular microenvironment. There is evidence that concurrent administration of some dietary phytochemicals enhances the efficacy of certain cancer treatments by increasing intracellular ROS accumulation. Paradoxically, consumption of the same dietary phytochemicals under conditions that result in the scavenging of ROS might also negatively affect the outcome of ROS-dependent cancer treatments. This review discusses the potential impact of consuming dietary phytochemicals with anti-oxidant and/or pro-oxidant activities on the effectiveness of concurrent chemotherapy and/or radiotherapy in cancer patients.

Emodin Promotes Apoptosis of Human Endometrial Cancer Through Regulating the MAPK and PI3K/ AKT Pathways

Emodin, a major component of rhubarb, has anti-tumor effects in a variety of cancers, influencing multiple steps of tumor development through modulating several signaling pathways. The aim of this study is to examine the effect of emodin on cell apoptosis and explore the underlying mechanisms in human endometrial cancer cells. Here we report that emodin can inhibit KLE cell proliferation and induce apoptosis in a time- and dose-dependent manner. Western blot assay found that emodin was involved in MAPK and PI3K/Akt signaling pathways. Specifically, emodin significantly suppressed the phosphorylation of AKT, and enhanced the phosphorylation of MAPK pathways. Furthermore, the generation of reactive oxygen species (ROS) was up-regulated in KLE cells upon treatment with emodin, while the anti-oxidant agent N-acetyl cysteine (NAC) can inhibit emodin-induced apoptosis and promote the activation of AKT and Bcl-2. Taken together, we revealed that emodin may induce apoptosis in KLE cells through regulating the PI3K/AKT and MAPK signaling pathways, indicating the importance of emodin as an anti-tumor agent.

Emodin inhibits TGF-β2 by activating the FOXD3/miR‑199a axis in ovarian cancer cells in vitro

Ovarian cancer is a highly metastatic malignancy and a leading cause of cancer-related death in postmenopausal women. Emodin is a natural anthraquinone isolated from several traditional Chinese medicines including Rhubarb and Polygonum cuspidatum. Recently, emodin was demonstrated to reduce the growth of human ovarian carcinoma cells. However, the mechanism remains unclear. In the present study, we identified that transforming growth factor (TGF)-β2 was significantly affected by emodin treatment in A2780 cells using microarray analysis. MicroRNA (miR)-199a was predicted as a potential miRNA targeting TGF-β2 by in silico prediction using TargetScan. The mRNA and protein levels of TGF-β2 were both significantly reduced by miR-199a. Spearman's correlation analysis revealed a significant correlation between the expression level of miR-199a and TGF-β2 in human ovarian cancer specimens. Silencing of miR-199a with miR-199a inhibitor significantly restored the reduction in TGF-β2 expression induced by emodin. Additionally, cell viability and colony formation of A2780 cells were markedly inhibited by emodin treatment, which was mediated by miR-199a. We analyzed the primary mature miR-199a-1 and miR-199a-2 transcripts in A2780 cells treated with emodin or dimethyl sulfoxide (DMSO) and found that only pri-miR-199a-1 was regulated by emodin. A conserved binding site of Forkhead box D3 (FOXD3) was identified within pri-miR-199a-1. We further revealed that miR-199a expression was significantly regulated by FOXD3. Taken together, the present study demonstrated that emodin may directly promote FOXD3 expression and sequentially activates miR-199a, which in turn suppresses the expression of TGF-β2 to reduce cell viability and colony formation of A2780 cells.

MicroRNA-218 Increases the Sensitivity of Bladder Cancer to Cisplatin by Targeting Glut1

Background/Aims: MicroRNA-218 (miR-218) is down-regulated in many malignancies that have been implicated in the regulation of diverse processes in cancer cells. However, the involvement of miR-218 in chemo-sensitivity to cisplatin and the precise mechanism of this action remained unknown in bladder cancer. Methods: qRT-PCR was used to detect miR-218 and its target Glut1 expression in bladder cancer cell lines T24 and EJ. CCK-8 method was utilized to measure the cell viability. IC 50 was calculated via a probit regression model. Glut1 was detected by western blotting for analysis of potential mechanism. Luciferase reporter assay was utilized to validate Glut1 as a direct target gene of miR-218. The intracellular level of GSH and ROS were determined using a commercial colorimetric assay kit and 2’, 7’-dichlorodihydro-fluorescein diacetate, respectively. Results: Over-expression of miR-218 significantly reduced the rate of glucose uptake and total level of GSH and enhanced the chemo-sensitivity of bladder cancer to cisplatin. Mechanistically, Glut1 was found to be a direct and functional target of miR-218. Up-regulation of Glut1 could restore chemo-resistance in T24 and EJ cells. On the contrary, knockdown of Glut1 could generate a similar effect as up-regulating the expression of miR-218. Conclusions: MiR-218 increases the sensitivity of bladder cancer to cisplatin by targeting Glut1. Restoration of miR-218 and repression of glut1 may provide a potential strategy to restore chemo-sensitivity in bladder cancer.

Cancer Cell Specific Delivery of Photosystem I Through Integrin Targeted Liposome Shows Significant Anticancer Activity

Many anticancer drugs are developed for the treatment of cancer from natural sources. Photosystem I (PSI), a protein complex present in the chloroplast, is involved in photosynthesis and generates reactive oxygen species (ROS) in plant. Here, we used the ROS generation property of PSI for cancer therapy. We show that PSI can enter into different kinds of cancer cell like human lung carcinoma (A549) and mouse melanoma (B16F10) cell lines and generate ROS inside the cells. It inhibits the proliferation of cancer cell and causes apoptotic death of cancer cells. We also show that PSI induces apoptosis through mitochondria-dependent internal pathway, induces caspase3, causes DNA fragmentation, and arrests cell cycle at SubG0 phase. We also prepared, using C₁₆-LDV lipopeptide [C16 long chain attached on the N-terminal of the tripeptide containing amino acids leucine (L), aspartic acid (D), and valine (V) abbreviated as NH₂-LDV-COOH], α₄β₁ integrin targeted liposomal formulation of PSI, which specifically kills the cancer cell without affecting normal cells, and it is found to be more potent compared to clinically used drug doxorubicin. Finally, we found that LDV liposomal formulation of PSI inhibits the growth of tumor in C57BL/6J mice model.

The timing of caffeic acid treatment with cisplatin determines sensitization or resistance of ovarian carcinoma cell lines

Cisplatin is a widely used chemotherapeutic drug showing high efficiency in the treatment of primary tumors such as ovarian, testicular and cervical cancers. The major drawback of cisplatin is tumor resistance either acquired or intrinsic. Many mechanisms are involved in the resistance, among them is the Nrf2 pathway which regulates glutathione related enzymes. Caffeic acid, a non-toxic polyphenol which is abundant in many foods modulates glutathione S-transferase (GST) and glutathione reductase (GSR) activity, these enzymes were shown to be involved in resistance of cells towards cisplatin. Caffeic acid induces the Nrf2 pathway and can also inhibit the activity of GST and GSR. Our findings demonstrate that the co-treatment of cancer cells with cisplatin and caffeic acid can enhance cisplatin cytotoxicity and increases the amount of platinum bound to nuclear DNA. However, 6h of pre incubation with caffeic acid prior to cisplatin treatment led to acquired resistance to cisplatin and reduced DNA binding. In conclusion, the enzyme inhibitory action of caffeic acid is dominant when the two agents are co-administered leading to increased cytotoxicity, and the Nrf2 induction is dominant when the cells are treated with caffeic acid prior to cisplatin treatment leading to resistance. The use of caffeic acid as adjuvant for cisplatin should be carefully examined due to different pharmacokinetic profiles of caffeic acid and cisplatin. Thus, it is questionable if the two agents can reach the tumors at the right time frame in vivo.

Activation of AMPKα mediates additive effects of solamargine and metformin on suppressing MUC1 expression in castration-resistant prostate cancer cells

Prostate cancer is the second most common cause of cancer-related deaths worldwide. The mucin 1 (MUC1) oncoprotein is highly expressed in human prostate cancers with aggressive features. However, the role for MUC1 in occurrence and progression of castration-resistant prostate cancer (CRPC) remained elusive. In this study, we showed that solamargine, a major steroidal alkaloid glycoside, inhibited the growth of CRPC cells, which was enhanced in the presence of metformin. Furthermore, we found that solamargine increased phosphorylation of AMPKα, whereas reducing the protein expression and promoter activity of MUC1. A greater effect was observed in the presence of metformin. In addition, solamargine reduced NF-κB subunit p65 protein expression. Exogenously expressed p65 resisted solamargine-reduced MUC1 protein and promoter activity. Interestingly, exogenously expressed MUC1 attenuated solamargine-stimulated phosphorylation of AMPKα and, more importantly reversed solamargine-inhibited cell growth. Finally, solamargine increased phosphorylation of AMPKα, while inhibiting MUC1, p65 and tumor growth were observed in vivo. Overall, our results show that solamargine inhibits the growth of CRPC cells through AMPKα-mediated inhibition of p65, followed by reduction of MUC1 expression in vitro and in vivo. More importantly, metformin facilitates the antitumor effect of solamargine on CRPC cells.

WITHDRAWN: Emodin increases expression of insulin-like growth factor binding protein 1 through activation of MEK/ERK/AMPKα and interaction of PPARγ and Sp1 in lung cancer

Due to an error in the publishing process, this article has been withdrawn at the request of the editors. We wish to clarify that this is in no way related to the integrity of the authors. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Cisplatin and resveratrol induce apoptosis and autophagy following oxidative stress in malignant mesothelioma cells

Malignant mesothelioma (MM) is characterized by poor responsiveness to current chemotherapeutic drugs, usually owing to high resistance to apoptosis. Here, we investigated chemosensitizing effects of phytochemical resveratrol, in combination with cisplatin, on MM cells. The combination treatment of cisplatin and resveratrol (CDDP/RSV) synergistically induced apoptosis, as evidenced by typical cell morphological changes, the appearance of sub-G0/G1 peak, an increase in the Annexin V(+) cells and the cleavage of caspase-3 and PARP. CDDP/RSV increased ROS production and depolarization of mitochondrial membrane potential with an increase in the Bax/Bcl-2 ratio. These changes were attenuated by pretreatment with N-acetylcysteine, suggesting that CDDP/RSV induced apoptosis through oxidative mitochondrial damage. Compared with MSTO-211H cells, CDDP/RSV was less efficient in killing H-2452 cells. H-2452 cells exhibited an enhanced autophagy to CDDP/RSV, as observed by an increase in viable cells exhibiting intense LysoTracker Red staining and up-regulation of Beclin-1 and LC3A. Inhibition of autophagy by bafilomycin A1 rendered cells more sensitive to CDDP/RSV-induced cytotoxicity and this was associated with induction of apoptosis. These data indicate that the increased resistance of H-2452 cells to CDDP/RSV is closely related to the activation of self-defensive autophagy, and provide the rationale for targeting the autophagy regulation in the treatment of MM.

Emodin: A Review of its Pharmacology, Toxicity and Pharmacokinetics

Emodin is a natural anthraquinone derivative that occurs in many widely used Chinese medicinal herbs, such as Rheum palmatum, Polygonum cuspidatum and Polygonum multiflorum. Emodin has been used as a traditional Chinese medicine for over 2000 years and is still present in various herbal preparations. Emerging evidence indicates that emodin possesses a wide spectrum of pharmacological properties, including anticancer, hepatoprotective, antiinflammatory, antioxidant and antimicrobial activities. However, emodin could also lead to hepatotoxicity, kidney toxicity and reproductive toxicity, particularly in high doses and with long-term use. Pharmacokinetic studies have demonstrated that emodin has poor oral bioavailability in rats because of its extensive glucuronidation. This review aims to comprehensively summarize the pharmacology, toxicity and pharmacokinetics of emodin reported to date with an emphasis on its biological properties and mechanisms of action. Copyright © 2016 John Wiley & Sons, Ltd.

A Mechanism for the Temporal Potentiation of Genipin to the Cytotoxicity of Cisplatin in Colon Cancer Cells

OBJECTIVES

To investigate the potentiation effect of Genipin to Cisplatin induced cell senescence in HCT-116 colon cancer cells in vitro.

METHODS

Cell viability was estimated by Propidium iodide and Hoechst 3342, reactive oxygen species (ROS) with DHE, mitochondrial membrane potential (MMP) with JC-1 MMP assay Kit and electron current production with microbial fuel cells (MFC).

RESULTS

Genipin inhibited the UCP2 mediated anti-oxidative proton leak significantly promoted the Cisplatin induced ROS and subsequent cell death, which was similar to that of UCP2-siRNA. Cells treated with Cisplatin alone or combined with Genipin, ROS negatively, while MMP positively correlated with cell viability. Cisplatin induced ROS was significantly decreased by detouring electrons to MFC, or increased by Genipin combined treatment. Compensatory effects of UCP2 up-regulation with time against Genipin treatment were suggested. Shorter the Genipin treatment before Cisplatin better promoted the Cisplatin induced ROS and subsequent cell death.

CONCLUSION

The interaction of leaked electron with Cisplatin was important during ROS generation. Inhibition of UCP2-mediated proton leak with Genipin potentiated the cytotoxicity of Cisplatin. Owing to the compensatory effects against Genipin, shorter Genipin treatment before Cisplatin was recommended in order to achieve better potentiation effect.

Pro-oxidant activity of polyphenols and its implication on cancer chemoprevention and chemotherapy

Reactive oxygen species (ROS) play a major role in carcinogenesis: pro-oxidant agents like tobacco smoke, asbestos or N-nitrosamines, are known as mutagenic and carcinogenic, and cancer cells show increased levels of ROS and redox deregulation. However, pro-oxidant molecules can also act as selective cytotoxic agents against cancer cells by achieving toxic levels of ROS. Although polyphenols are well-known as potent antioxidants, a pro-oxidant effect has been associated with their pro-apoptotic effect in various types of tumor cells. The aim of the present review is to present the main evidences of the pro-oxidant-related cytotoxic activity of naturally occurring polyphenols and their underlying mechanisms.

Sanguinarine-induced apoptosis in lung adenocarcinoma cells is dependent on reactive oxygen species production and endoplasmic reticulum stress

Sanguinarine (SAN), an alkaloid isolated from plants of the Papaveraceae family, is a compound with multiple biological activities. In the present study, we explored the anticancer properties of SAN in lung cancer using the human lung adenocarcinoma cell line SPC-A1. Our results revealed that SAN inhibited SPC-A1 cell growth and induced apoptosis in a dose-dependent manner. We found that SAN triggered reactive oxygen species (ROS) production, while elimination of ROS by N-acetylcysteine (NAC) reversed the growth inhibition and apoptosis induced by SAN. SAN-induced endoplasmic reticulum (ER) stress resulted in the upregulation of many genes and proteins involved in the unfolded protein response (UPR) pathway, including glucose-regulated protein 78 (GRP78), p-protein kinase R (PKR)-like ER kinase (PERK), p-eukaryotic translation initiation factor 2α (eIF2α), activating transcription factor 4 (ATF4) and CCAAT/enhancer binding protein homologous protein (CHOP). Blocking ER stress with tauroursodeoxycholic acid (TUDCA) markedly reduced SAN-induced inhibition of growth and apoptosis. Furthermore, TUDCA decreased SAN-induced ROS production, and NAC attenuated SAN-induced GRP78 and CHOP expression. Overall, our data indicate that the anticancer effects of SAN in lung cancer cells depend on ROS production and ER stress and that SAN may be a potential agent against lung cancer.