Emodin-induced generation of reactive oxygen species inhibits RhoA activation to sensitize gastric carcinoma cells to anoikis

Role of emodin to prevent gastrointestinal cancers: recent trends and future prospective

Gastrointestinal malignancies are responsible for approximately 35% of all cancer-related deaths, underscoring the critical need to explore pharmacologically active molecules for chemoprevention. Emodin (1,3,8-trihydroxy-6-methylanthraquinone), a natural compound derived from traditional Chinese and Japanese medicine, has recently garnered significant attention for its potential anticancer properties. Emodin exerts its chemoprotective effects through a combination of antioxidative, anti-inflammatory, and anti-proliferative mechanisms. Research indicates that emodin inhibits cancer metastasis, disrupts cell cycle progression, and impairs cancer cell survival. These effects are mediated through the activation of the p38 MAPK/JNK1/2 signaling pathway, the upregulation of pro-apoptotic factors such as Bax/Bcl-2 and caspases, and the enhancement of reactive oxygen species (ROS) levels (Supplementary Fig. 1). To optimize emodin's therapeutic potential, it is crucial to further investigate its underlying mechanisms of action and develop advanced nano-targeted delivery systems to enhance its bioavailability. This review highlights emodin's promise as a chemopreventive agent for gastrointestinal cancers and emphasizes its potential for development into a novel clinical formulation.

Identifying the function of novel cross-species microRNAs from the excretory-secretory products of Angiostrongylus cantonensis fifth-stage larvae

BACKGROUND

Angiostrongylus cantonensis is a significant foodborne zoonotic parasite that causes severe neuropathological damage and symptoms in humans. Excretory-secretory products (ESPs) play a pivotal role in elucidating host-parasite interactions and can aid in penetrating host defensive barriers in helminths. Recently, secreted microRNAs have become important research targets for parasite-host communication. In this study, we determined the expression and function of novel microRNAs from A. cantonensis L5 ESPs and evaluated the effect of target microRNAs on the molecular mechanisms of mouse astrocytes.

METHODS

Here, we employed next-generation sequencing (NGS) to establish the secreted microRNAs dataset. Next, we evaluated the effects of AcESPs-microRNAs in A. cantonensis ESPs treated astrocytes.

RESULTS

First, we established the secreted microRNA dataset, and then comprehensively verified the characteristics. Novel microRNAs were initially detected, and their expression was found. Moreover, the prediction results showed that these secreted microRNAs may regulate Wnt and mTOR signaling. Next, the data showed that the AcNOVEL55 microRNA reduced cell apoptosis generation via regulating the RhoA-Rock signaling pathway in A. cantonensis L5 ESPs treated mouse astrocytes. Moreover, we also demonstrated that the AcNOVEL31 microRNA can affect the inflammation activation via regulating the presenilin-1/GSK3B/β-catenin/NF-κB pathway. Finally, the concentrations of secreted IL-6 and IL-12 proteins were downregulated by AcNOVEL31 microRNA by influencing presenilin-1 expression.

CONCLUSION

This is the first study to verify the molecular functions of novel microRNAs secreted by A. cantonensis. The discovery of the microRNA mechanisms by which cross-species parasitic nematodes influence hosts has advanced research on host-parasitic nematode interactions.

Reactive Oxygen Species and its Manipulation Strategies in Cancer Treatment

Cancer is one of the serious diseases of modern times, occurring in all parts of the world and shows a wide range of effects on the human body. Reactive Oxygen Species (ROS) such as oxide and superoxide ions have both advantages and disadvantages during the progression of cancer, dependent on their concentration. It is a necessary part of the normal cellular mechanisms. Changes in its normal level can cause oncogenesis and other relatable problems. Metastasis can also be controlled by ROS levels in the tumor cells, which can be prevented by the use of antioxidants. However, ROS is also used for the initiation of apoptosis in cells by different mediators. There exists a cycle between the production of oxygen reactive species, their effect on the genes, role of mitochondria and the progression of tumors. ROS levels cause DNA damage by the oxidation process, gene damage, altered expression of the genes and signalling mechanisms. They finally lead to mitochondrial disability and mutations, resulting in cancer. This review summarizes the important role and activity of ROS in developing different types of cancers like cervical, gastric, bladder, liver, colorectal and ovarian cancers.

Targeting Peroxisome Proliferator-Activated Receptor-β/δ, Reactive Oxygen Species and Redox Signaling with Phytocompounds for Cancer Therapy

Significance: Peroxisome proliferator-activated receptors (PPARs) have a moderately preserved amino-terminal domain, an extremely preserved DNA-binding domain, an integral hinge region, and a distinct ligand-binding domain that are frequently encountered with the other nuclear receptors. PPAR-β/δ is among the three nuclear receptor superfamily members in the PPAR group. Recent Advances: Emerging studies provide an insight on natural compounds that have gained increasing attention as potential anticancer agents due to their ability to target multiple pathways involved in cancer development and progression. Critical Issues: Modulation of PPAR-β/δ activity has been suggested as a potential therapeutic strategy for cancer management. This review focuses on the ability of bioactive phytocompounds to impact reactive oxygen species (ROS) and redox signaling by targeting PPAR-β/δ for cancer therapy. The rise of ROS in cancer cells may play an important part in the initiation and progression of cancer. However, excessive levels of ROS stress can also be toxic to the cells and cancer cells with increased oxidative stress are likely to be more vulnerable to damage by further ROS insults induced by exogenous agents, such as phytocompounds and therapeutic agents. Therefore, redox modulation is a way to selectively kill cancer cells without causing significant toxicity to normal cells. However, use of antioxidants together with cancer drugs may risk the effect of treatment as both act through opposite mechanisms. Future Directions: It is advisable to employ more thorough and detailed methodologies to undertake mechanistic explorations of numerous phytocompounds. Moreover, conducting additional clinical studies is recommended to establish optimal dosages, efficacy, and the impact of different phytochemicals on PPAR-β/δ.

Elucidation of the anti-gastric cancer mechanism of Guiqi Baizhu Formula by integrative approach of chemical bioinformatics

Gastric cancer (GC) has posed a great threat to the lives of people around the world. To date, safer and more cost-effective therapy for GC is lacking. Traditional Chinese medicine (TCM) may provide some new options for this. Guiqi Baizhu Formula (GQBZF), a classic TCM formula, has been extensively used to treat GC, while its bioactive components and therapeutic mechanisms remain unclear. In this study, we evaluated the underlying mechanisms of GQBZF in treating GC by integrative approach of chemical bioinformatics. GQBZF lyophilized powder (0.0625 mg/mL, 0.125 mg/mL) significantly attenuated the expression of p-IGF1R, PI3K, p-PDK1, p-VEGFR2 to inhibit the proliferation, migration and induce apoptosis of gastric cancer cells, which was consistent with the network pharmacology. Additionally, atractylenolide Ⅰ, quercetin, glycyrol, physcione and aloe-emodin, emodin, kaempferol, licoflavone A were found to be the key compounds of GQBZF regulating IGF1R and VEGFR2, respectively. And among which, glycyrol and emodin were determined as key active compounds against GC by farther vitro experiments and LC/MS. Meanwhile, we also found that glycyrol inhibited MKN-45 cells proliferation and enhanced apoptosis, which might be related to the inhibition of IGF1R/PI3K/PDK1, and emodin could significantly attenuate the MKN-45 cells migration, which might be related to the inhibition of VEGFR2-related signaling pathway. These results were verified again by molecular dynamics simulation and binding interaction pattern. In summary, this study suggested that GQBZF and its key active components (glycyrol and emodin) can suppress IGF1R/PI3K/PDK1 and VEGFR2-related signaling pathway, thereby inhibiting tumor cell proliferation and migration and inducing apoptosis. These findings provided an important strategy for developing new agents and facilitated clinical use of GQBZF against GC.

Fluoride-Induced Mitochondrial Dysfunction and Approaches for Its Intervention

Fluoride is present everywhere in nature. The primary way that individuals are exposed to fluoride is by drinking water. It's interesting to note that while low fluoride levels are good for bone and tooth growth, prolonged fluoride exposure is bad for human health. Additionally, preclinical studies link oxidative stress, inflammation, and programmed cell death to fluoride toxicity. Moreover, mitochondria play a crucial role in the production of reactive oxygen species (ROS). On the other hand, little is known about fluoride's impact on mitophagy, biogenesis, and mitochondrial dynamics. These actions control the growth, composition, and organisation of mitochondria, and the purification of mitochondrial DNA helps to inhibit the production of reactive oxygen species and the release of cytochrome c, which enables cells to survive the effects of fluoride poisoning. In this review, we discuss the different pathways involved in mitochondrial toxicity and dysfunction induced by fluoride. For therapeutic approaches, we discussed different phytochemical and pharmacological agents which reduce the toxicity of fluoride via maintained by imbalanced cellular processes, mitochondrial dynamics, and scavenging the ROS.

Identification and verification of a novel anoikis-related gene signature with prognostic significance in clear cell renal cell carcinoma

PURPOSE

Clear cell renal cell carcinomas (ccRCCs) are the most common form of renal cancer in the world. The loss of extracellular matrix (ECM) stimulates cell apoptosis, known as anoikis. A resistance to anoikis in cancer cells is believed to contribute to tumor malignancy, particularly metastasis; however, the potential influence of anoikis on the prognosis of ccRCC patients is not fully understood.

METHODS

In this study, anoikis-related genes (ARGs) with discrepant expression were selected from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. The anoikis-related gene signature (ARS) was built using a combination of the univariate Cox and least absolute shrinkage and selection operator (LASSO) analyses. ARS was also evaluated for their prognostic value. We explored the tumor microenvironment and enrichment pathways between different clusters of ccRCC. We also examined differences in clinical characteristics, immune cell infiltration and drug sensitivity between the high- and low-risk sets. In addition, we utilized three external databases and quantitative real-time polymerase chain reaction (qRT-PCR) to validate the expression and prognosis of ARGs.

RESULTS

Eight ARGs (PLAUR, HMCN1, CDKN2A, BID, GLI2, PLG, PRKCQ and IRF6) were identified as anoikis-related prognostic factors. According to Kaplan-Meier (KM) analysis, ccRCC patients with high-risk ARGs have a worse prognosis. The risk score was found to be a significant independent prognostic indicator. According to tumor microenvironment (TME) scores, stromal score, immune score, and estimated score of the high-risk group were superior to those of the low-risk group. There were significant differences between the two groups regarding the amount of infiltrated immune cells, immune checkpoint expression as well as drug sensitivity. A nomogram was constructed using ccRCC clinical features and risk scores. The signature and the nomogram both performed well in predicting overall survival (OS) for ccRCC patients. According to a decision curve analysis (DCA), clinical treatment options for patients with ccRCC could be improved using this model.

CONCLUSION

The results of validation from external databases and qRT-PCR were basically agreement with findings in TCGA and GEO databases. The ARS serving as biomarkers may provide an important reference for individual therapy of ccRCC patients.

A Mitochondrion-Targeting Protein (B2) Primes ROS/Nrf2-Mediated Stress Signals, Triggering Apoptosis and Necroptosis in Lung Cancer

The betanodavirus B2 protein targets mitochondria and triggers mitochondrion-mediated cell death signaling in lung cancer cells; however, its molecular mechanism remains unknown. In this study, we observed that B2 triggers hydrogen peroxide/Nrf2-involved stress signals in the dynamic regulation of non-small lung cancer cell (NSCLC)-programmed cell death. Here, the B2 protein works as a necrotic inducer that triggers lung cancer death via p53 upregulation and RIP3 expression, suggesting a new perspective on lung cancer therapy. We employed the B2 protein to target A549 lung cancer cells and solid tumors in NOD/SCID mice. Tumors were collected and processed for the hematoxylin and eosin staining of tissue and cell sections, and their sera were used for blood biochemistry analysis. We observed that B2 killed an A549 cell-induced solid tumor in NOD/SCID mice; however, the mutant ΔB2 did not. In NOD/SCID mice, B2 (but not ΔB2) induced both p53/Bax-mediated apoptosis and RIPK3-mediated necroptosis. Finally, immunochemistry analysis showed hydrogen peroxide /p38/Nrf2 stress strongly inhibited the production of tumor markers CD133, Thy1, and napsin, which correlate with migration and invasion in cancer cells. This B2-triggered, ROS/Nrf2-mediated stress signal triggered multiple signals via pathways that killed A549 lung cancer tumor cells in vivo. Our results provide novel insight into lung cancer management and drug therapy.

Potential therapeutic targets discovery by transcriptome analysis of an in vitro human gastric signet ring carcinoma model

BACKGROUND

Loss of E-cadherin expression is frequently observed in signet ring carcinoma (SRCC). People with germline mutations in CDH1, which encodes E-cadherin, develop diffuse gastric cancer at a higher rate. Loss of E-cadherin expression is thus assumed to trigger oncogenic development.

METHODS

To investigate novel therapeutic targets for gastric SRCC, we engineered an E-cadherin-deficient SRCC model in vitro using a human gastric organoid (hGO) with CDH1 knockout (KO).

RESULTS

CDH1 KO hGO cells demonstrated distinctive morphological changes similar to SRCC and high cell motility. RNA-sequencing revealed up-regulation of matrix metalloproteinase (MMP) genes in CDH1 KO hGO cells compared to wild type. MMP inhibitors suppressed cell motility of CDH1 KO hGO cells and SRCC cell lines in vitro. Immunofluorescent analysis with 95 clinical gastric cancer tissues revealed that MMP-3 was specifically abundant in E-cadherin-aberrant SRCC. In addition, CXCR4 molecules translocated onto the cell membrane after CDH1 KO. Addition of CXCL12, a ligand of CXCR4, to the culture medium prolonged cell survival of CDH1 KO hGO cells and was abolished by the inhibitor, AMD3100. In clinical SRCC samples, CXCL12-secreting fibroblasts showed marked infiltration into the cancer area.

CONCLUSIONS

E-cadherin deficient SRCCs might gain cell motility through upregulation of MMPs. CXCL12-positive cancer-associated fibroblasts could serve to maintain cancer-cell survival as a niche. MMPs and the CXCL12/CXCR4 axis represent promising candidates as novel therapeutic targets for E-cadherin-deficient SRCC.

Phytochemicals as Potential Chemopreventive and Chemotherapeutic Agents for Emerging Human Papillomavirus-Driven Head and Neck Cancer: Current Evidence and Future Prospects

Head and neck cancer (HNC) usually arises from squamous cells of the upper aerodigestive tract that line the mucosal surface in the head and neck region. In India, HNC is common in males, and it is the sixth most common cancer globally. Conventionally, HNC attributes to the use of alcohol or chewing tobacco. Over the past four decades, portions of human papillomavirus (HPV)-positive HNC are increasing at an alarming rate. Identification based on the etiological factors and molecular signatures demonstrates that these neoplastic lesions belong to a distinct category that differs in pathological characteristics and therapeutic response. Slow development in HNC therapeutics has resulted in a low 5-year survival rate in the last two decades. Interestingly, HPV-positive HNC has shown better outcomes following conservative treatments and immunotherapies. This raises demand to have a pre-therapy assessment of HPV status to decide the treatment strategy. Moreover, there is no HPV-specific treatment for HPV-positive HNC patients. Accumulating evidence suggests that phytochemicals are promising leads against HNC and show potential as adjuvants to chemoradiotherapy in HNC. However, only a few of these phytochemicals target HPV. The aim of the present article was to collate data on various leading phytochemicals that have shown promising results in the prevention and treatment of HNC in general and HPV-driven HNC. The review explores the possibility of using these leads against HPV-positive tumors as some of the signaling pathways are common. The review also addresses various challenges in the field that prevent their use in clinical settings.

Emodin Inhibits the Proliferation of MCF-7 Human Breast Cancer Cells Through Activation of Aryl Hydrocarbon Receptor (AhR)

Natural products have proved to be a promising source for the development of potential anticancer drugs. Emodin, a natural compound from Rheum palmatum, is used to treat several types of cancers, including lung, liver, and pancreatic. However, there are few reports regarding its use in the treatment of breast cancer. Thus, the therapeutic effect and mechanism of emodin on MCF-7 human breast cancer cells were investigated in this study. Morphological observations and cell viability were evaluated to determine the anti-proliferation activity of emodin. Network pharmacology and molecular docking were performed to screen the potential targets. Western blot analysis was used to explore a potential antitumor mechanism. The results showed that emodin (50–100 μmol/L) could significantly inhibit the proliferation of MCF-7 cells in a time and dose-dependent manner. Furthermore, virtual screening studies indicated that emodin was a potent aryl hydrocarbon receptor (AhR) agonist in chemotherapy for breast cancer. Finally, when MCF-7 cells were treated with emodin (100 μmol/L) for 24 h, the AhR and cytochrome P450 1A1 (CYP1A1) protein expression levels were significantly upregulated compared with the control group. Our study indicated that emodin exhibited promising antitumor activity in MCF-7 cells, likely through activation of the AhR-CYP1A1 signaling pathway. These findings lay a foundation for the application of emodin in breast cancer treatment.

Role of Phytochemicals in Perturbation of Redox Homeostasis in Cancer

Over the past few decades, research on reactive oxygen species (ROS) has revealed their critical role in the initiation and progression of cancer by virtue of various transcription factors. At certain threshold values, ROS act as signaling molecules leading to activation of oncogenic pathways. However, if perturbated beyond the threshold values, ROS act in an anti-tumor manner leading to cellular death. ROS mediate cellular death through various programmed cell death (PCD) approaches such as apoptosis, autophagy, ferroptosis, etc. Thus, external stimulation of ROS beyond a threshold is considered a promising therapeutic strategy. Phytochemicals have been widely regarded as favorable therapeutic options in many diseased conditions. Over the past few decades, mechanistic studies on phytochemicals have revealed their effect on ROS homeostasis in cancer. Considering their favorable side effect profile, phytochemicals remain attractive treatment options in cancer. Herein, we review some of the most recent studies performed using phytochemicals and, we further delve into the mechanism of action enacted by individual phytochemicals for PCD in cancer.

A Double-Edged Sword: The Anti-Cancer Effects of Emodin by Inhibiting the Redox-Protective Protein MTH1 and Augmenting ROS in NSCLC

Background: Reactive oxygen species (ROS), playing a two-fold role in tumorigenesis, are responsible for tumor formation and progression through the induction of genome instability and pro-oncogenic signaling. The same ROS is toxic to cancer cells at higher levels, oxidizing free nucleotide precursors (dNTPs) as well as damaging DNA leading to cell senescence. Research has highlighted the tumor cell-specific expression of a redox-protective phosphatase, MutT homolog 1 (MTH1), that performs the enzymatic conversion of oxidized nucleotides (like 8-oxo-dGTP) to their corresponding monophosphates, up-regulated in numerous cancers, circumventing their misincorporation into the genomic DNA and preventing damage and cell death. Methods: To identify novel natural small molecular inhibitors of MTH1 to be used as cancer therapeutic agents, molecular screening for MTH1 active site binders was performed from natural small molecular libraries. Emodin was identified as a lead compound for MTH1 active site functional inhibition and its action on MTH1 inhibition was validated on non-small cell lung cancer cellular models (NSCLC). Results: Our study provides strong evidence that emodin mediated MTH1 inhibition impaired NSCLC cell growth, inducing senescence. Emodin treatment enhanced the cellular ROS burdens, on one hand, damaged dNTP pools and inhibited MTH1 function on the other. Our work on emodin indicates that ROS is the key driver of cancer cell-specific increased DNA damage and apoptosis upon MTH1 inhibition. Consequently, we observed a time-dependent increase in NSCL cancer cell susceptibility to oxidative stress with emodin treatment. Conclusions: Based on our data, the anti-cancer effects of emodin as an MTH1 inhibitor have clinical potential as a single agent capable of functioning as a ROS inducer and simultaneous blocker of dNTP pool sanitation in the treatment of NSCL cancers. Collectively, our results have identified for the first time that the potential molecular mechanism of emodin function, increasing DNA damage and apoptosis in cancer cells, is via MTH1 inhibition.

Hyaluronic Acid Improves Hydrogen Peroxide Modulatory Effects on Calcium Channel and Sodium-Potassium Pump in 4T1 Breast Cancer Cell Line

Maintaining homeostasis of ion concentrations is critical in cancer cells. Under hypoxia, the levels of channels and pumps in cancer cells are more active than normal cells suggesting ion channels as a suitable therapeutic target. One of the contemporary ways for cancer therapy is oxidative stress. However, the effective concentration of oxidative stress on tumor cells has been reported to be toxic for normal cells as well. In this study, we benefited from the modifying effects of hyaluronic acid (HA) on H2O2, as a free radical source, to make a gradual release of oxidative stress on cancer cells while preventing/decreasing damage to normal cells under normoxia and hypoxic conditions. To do so, we initially investigated the optimal concentration of HA antioxidant capacity by the DPPH test. In the next step, we found optimum H2O2 dose by treating the 4T1 breast cancer cell line with increasing concentrations (0, 10, 20, 50,100, 200, 500, and 1000 μM) of H2O2 alone or H2O2 + HA (83%) for 24 hrs. The calcium channel and the sodium-potassium pumps were then evaluated by measuring the levels of calcium, sodium, and potassium ions using an atomic absorption flame spectrophotometer. The results revealed that treatment with H2O2 or H2O2+ HA led to an intracellular increase of calcium, sodium, and potassium in the normoxic and hypoxic circumstances in a dose-dependent manner. It is noteworthy that H2O2 + HA treatment had more favorable and controllable effects compared with H2O2 alone. Moreover, HA optimizes the antitumor effect of oxidative stress exerted by H2O2 making H2O2 + HA suitable for clinical use in cancer treatment along with chemotherapy.

Inhibition or Reversal of the Epithelial-Mesenchymal Transition in Gastric Cancer: Pharmacological Approaches

Epithelial-mesenchymal transition (EMT) constitutes one of the hallmarks of carcinogenesis consisting in the re-differentiation of the epithelial cells into mesenchymal ones changing the cellular phenotype into a malignant one. EMT has been shown to play a role in the malignant transformation and while occurring in the tumor microenvironment, it significantly affects the aggressiveness of gastric cancer, among others. Importantly, after EMT occurs, gastric cancer patients are more susceptible to the induction of resistance to various therapeutic agents, worsening the clinical outcome of patients. Therefore, there is an urgent need to search for the newest pharmacological agents targeting EMT to prevent further progression of gastric carcinogenesis and potential metastases. Therapies targeted at EMT might be combined with other currently available treatment modalities, which seems to be an effective strategy to treat gastric cancer patients. In this review, we have summarized recent advances in gastric cancer treatment in terms of targeting EMT specifically, such as the administration of polyphenols, resveratrol, tangeretin, luteolin, genistein, proton pump inhibitors, terpenes, other plant extracts, or inorganic compounds.

lncRNA SNHG4 promotes cell proliferation, migration, invasion and the epithelial-mesenchymal transition process via sponging miR-204-5p in gastric cancer

Long non-coding (lnc)RNAs and microRNAs (miRNAs/miRs) have physiological and pathological functions in various diseases, including gastric cancer (GC). The current study explored the association between lncRNA small nucleolar RNA host gene 4 (SNHG4) and miR-148a-3p, and their functions in GC cells. SNHG4 expression and overall survival data were analyzed using bioinformatics, and the interaction of SNHG4 and miR-148a-3p was predicted using starBase and confirmed via a dual-luciferase reporter assay. Cell viability, colony formation ability and apoptosis rate were detected using Cell Counting Kit-8, colony formation and flow cytometry assays, respectively. Cell migration and invasion were determined via wound-healing and Transwell assays. mRNA and protein expression levels were determined via reverse transcription-quantitative PCR and western blotting. The results demonstrated that in GC tissues and cell lines, SNHG4 was highly expressed, while miR-204-5p expression was decreased, and that the expression levels of SNHG4 and miR-204-5p were negatively correlated. The downregulated expression of SNHG4 decreased the effects of miR-204-5p inhibitor on promoting cell proliferation, migration, invasion and epithelial-mesenchymal transition, but enhanced the inhibitory effect of miR-204-5p on GC cell apoptosis. The findings of the current study revealed the potential mechanism of the SNHG4-miR-204-5p pathway in GC, which may be conducive to the development of novel drugs against GC growth.

Hyaluronic acid optimises therapeutic effects of hydrogen peroxide-induced oxidative stress on breast cancer

Distinguishing the multiple effects of reactive oxygen species (ROS) on cancer cells is important to understand their role in tumour biology. On one side, ROS can be oncogenic by promoting hypoxic conditions, genomic instability and tumorigenesis. Conversely, elevated levels of ROS-induced oxidative stress can induce cancer cell death. This is evidenced by the conflicting results of research using antioxidant therapy, which in some cases promoted tumour growth and metastasis. However, some antioxidative or ROS-mediated oxidative therapies have also yielded beneficial effects. To better define the effects of oxidative stress, in vitro experiments were conducted on 4T1 and splenic mononuclear cells (MNCs) under hypoxic and normoxic conditions. Furthermore, hydrogen peroxide (H₂ O₂ ; 10-1,000 μM) was used as an ROS source alone or in combination with hyaluronic acid (HA), which is frequently used as drug delivery vehicle. Our result indicated that the treatment of cancer cells with H₂ O₂  + HA was significantly more effective than H₂ O₂ alone. In addition, treatment with H₂ O₂  + HA led to increased apoptosis, decreased proliferation, and multiphase cell cycle arrest in 4T1 cells in a dose-dependent manner under normoxic or hypoxic conditions. As a result, migratory tendency and the messenger RNA levels of vascular endothelial growth factor, matrix metalloproteinase-2 (MMP-2), and MMP-9 were significantly decreased in 4T1 cells. Of note, HA treatment combined with 100-1,000 μM H₂ O₂ caused more damage to MNCs as compared to treatment with lower concentrations (10-50 μM). Based on these results, we propose to administer high-dose H₂ O₂  + HA (100-1000 μM) for intratumoural injection and low doses for systemic administration. Intratumoural route could have toxic and inhibitory effects not only on the tumour but also on residential myeloid cells defending it, whereas systemic treatment could stimulate peripheral immune responses against the tumour. More in vivo research is required to confirm this hypothesis.

MicroRNA‑500a‑5p inhibits colorectal cancer cell invasion and epithelial‑mesenchymal transition

The development of malignant tumors is a series of complex processes, the majority of which have not been elucidated. The aim of the present study was to investigate the microRNAs (miRNAs/miR) that affect the migration and invasion abilities of CRC cells. Our previous reports have revealed that miR‑500a‑5p suppressed CRC cell growth and malignant transformation. The present study demonstrated that overexpression of miR‑500a‑5p reduced the expression of vimentin, while increasing the expression of E‑cadherin. Inhibition of miR‑500a‑5p resulted in spindle‑like morphological changes and reorganization of F‑actin in CRC cells. Furthermore, miR‑500a‑5p attenuated the transforming growth factor‑β signaling pathway in EMT. Additionally, emodin inhibited the miR‑500a‑5p inhibitor and suppressed the EMT process. In animal models of metastasis using nude mice, EMT and LoVo cell metastasis was modulated by miR‑500a‑5p. Therefore, the findings of the present study demonstrated that miR‑500a‑5p is associated with a positive therapeutic outcome in terms of invasion/migration of CRC cells and mesenchymal‑like cell changes.

Rational design of small molecule RHOA inhibitors for gastric cancer

Previously, we identified Ras homologous A (RHOA) as a major signaling hub in gastric cancer (GC), the third most common cause of cancer death in the world, prompting us to rationally design an efficacious inhibitor of this oncogenic GTPase. Here, based on that previous work, we extend those computational analyses to further pharmacologically optimize anti-RHOA hydrazide derivatives for greater anti-GC potency. Two of these, JK-136 and JK-139, potently inhibited cell viability and migration/invasion of GC cell lines, and mouse xenografts, diversely expressing RHOA. Moreover, JK-136's binding affinity for RHOA was >140-fold greater than Rhosin, a nonclinical RHOA inhibitor. Network analysis of JK-136/-139 vs. Rhosin treatments indicated downregulation of the sphingosine-1-phosphate, as an emerging cancer metabolic pathway in cell migration and motility. We assert that identifying and targeting oncogenic signaling hubs, such as RHOA, represents an emerging strategy for the design, characterization, and translation of new antineoplastics, against gastric and other cancers.

Role of Reactive Oxygen Species in Cancer Progression: Molecular Mechanisms and Recent Advancements

Reactive oxygen species (ROS) play a pivotal role in biological processes and continuous ROS production in normal cells is controlled by the appropriate regulation between the silver lining of low and high ROS concentration mediated effects. Interestingly, ROS also dynamically influences the tumor microenvironment and is known to initiate cancer angiogenesis, metastasis, and survival at different concentrations. At moderate concentration, ROS activates the cancer cell survival signaling cascade involving mitogen-activated protein kinase/extracellular signal-regulated protein kinases 1/2 (MAPK/ERK1/2), p38, c-Jun N-terminal kinase (JNK), and phosphoinositide-3-kinase/ protein kinase B (PI3K/Akt), which in turn activate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), matrix metalloproteinases (MMPs), and vascular endothelial growth factor (VEGF). At high concentrations, ROS can cause cancer cell apoptosis. Hence, it critically depends upon the ROS levels, to either augment tumorigenesis or lead to apoptosis. The major issue is targeting the dual actions of ROS effectively with respect to the concentration bias, which needs to be monitored carefully to impede tumor angiogenesis and metastasis for ROS to serve as potential therapeutic targets exogenously/endogenously. Overall, additional research is required to comprehend the potential of ROS as an effective anti-tumor modality and therapeutic target for treating malignancies.

The production of reactive oxygen species enhanced with the reduction of menadione by active thioredoxin reductase

Cytosolic thioredoxin reductase (TXNRD1) is an important selenoprotein that participates in the reduction of thioredoxin and many other redox-related substrates. The enhancement of ROS production to cause cancer cell death is an effective anticancer strategy. Herein, we found that menadione substantially increased ROS generation via interaction with TXNRD1. To elucidate the mechanism behind this, various TXNRD1 mutant proteins were used to investigate the relationship between ROS production and the reaction between enzymes and menadione. A mutation at the C-terminal active site -GCUG of TXNRD1 to -GSSG or -GC, or the N-terminal active site C59S, C64S, or the deletion of the C-terminal 16 amino acid residues caused the loss of TXNRD1 activity needed for the reduction of menadione and therefore resulted in the loss of the ROS production ability of menadione. In contrast, the mutation of -GCUG to -GCCG resulted in an increase in the TXNRD1 activity towards the reduction of menadione, thus leading to an increase in ROS production. The co-treatment of the TXNRD1 inhibitor aurothioglucose and menadione could significantly alleviate the efficiency of ROS generation in vitro and increase the viability of A549 cells. Moreover, menadione could be reduced by the glutathione system and caused ROS production with less efficiency. These results demonstrate that TXNRD1 can serve as an effective source to generate ROS, which may provide a novel anticancer method based on the use of menadione.

Impact of ROS Generated by Chemical, Physical, and Plasma Techniques on Cancer Attenuation

For the last few decades, while significant improvements have been achieved in cancer therapy, this family of diseases is still considered one of the deadliest threats to human health. Thus, there is an urgent need to find novel strategies in order to tackle this vital medical issue. One of the most pivotal causes of cancer initiation is the presence of reactive oxygen species (ROS) inside the body. Interestingly, on the other hand, high doses of ROS possess the capability to damage malignant cells. Moreover, several important intracellular mechanisms occur during the production of ROS. For these reasons, inducing ROS inside the biological system by utilizing external physical or chemical methods is a promising approach to inhibit the growth of cancer cells. Beside conventional technologies, cold atmospheric plasmas are now receiving much attention as an emerging therapeutic tool for cancer treatment due to their unique biophysical behavior, including the ability to generate considerable amounts of ROS. This review summarizes the important mechanisms of ROS generated by chemical, physical, and plasma approaches. We also emphasize the biological effects and cancer inhibition capabilities of ROS.

RHOA in Gastric Cancer: Functional Roles and Therapeutic Potential

The well-known signal mediator and small GTPase family member, RHOA, has now been associated with the progression of specific malignancies. In this review, we appraise the biomedical literature regarding the role of this enzyme in gastric cancer (GC) signaling, suggesting potential clinical significance. To that end, we examined RHOA activity, with regard to second-generation hallmarks of cancer, finding particular association with the hallmark "activation of invasion and metastasis." Moreover, an abundance of studies show RHOA association with Lauren classification diffuse subtype, in addition to poorly differentiated GC. With regard to therapeutic value, we found RHOA signaling to influence the activity of specific widely used chemotherapeutics, and its possible antagonism by various dietary constituents. We also review currently available targeted therapies for GC. The latter, however, showed a paucity of such agents, underscoring the urgent need for further investigation into treatments for this highly lethal malignancy.

Emodin induced necroptosis in the glioma cell line U251 via the TNF-α/RIP1/RIP3 pathway

Emodin, an anthraquinone compound extracted from rhubarb and other traditional Chinese medicines, has been proven to have a wide range of pharmacological effects, such as anti-inflammatory, antiviral, and antitumor activities. Previous studies have confirmed that emodin has inhibitory effects on various solid tumors, such as osteosarcoma, liver cancer, prostate cancer and glioma. This study aimed to investigate the effects and mechanisms of emodin-induced necroptosis in the glioma cell line U251 by targeting the TNF-α/RIP1/RIP3 signaling pathway. We found that emodin could significantly inhibit U251 cell proliferation, and the viability of U251 cells treated with emodin was reduced in a dose- and time-dependent manner. Flow cytometry assays and Hoechst-PI staining assays showed that emodin induced apoptosis and necroptosis. Real-time PCR and western blot analysis showed that emodin upregulated the levels of TNF-α, RIP1, RIP3 and MLKL. Furthermore, the RIP1 inhibitor Nec-1 and the RIP3 inhibitor GSK872 attenuated the killing effect of emodin on U251 cells. In addition, emodin could increase the levels of TNF-α, RIP1, RIP3 and MLKL in vivo. The results demonstrate that emodin could induce necroptosis in glioma possibly through the activation of the TNF-α/RIP1/RIP3 axis. These studies provide novel insight into the induction of necroptosis by emodin and indicate that emodin might be a potential candidate for treating glioma through the necroptosis pathway.

Paraquat initially damages cochlear support cells leading to anoikis-like hair cell death

Paraquat (PQ), one of the most widely used herbicides, is extremely dangerous because it generates the highly toxic superoxide radical. When paraquat was applied to cochlear organotypic cultures, it not only damaged the outer hair cells (OHCs) and inner hair cells (IHCs), but also caused dislocation of the hair cell rows. We hypothesized that the dislocation arose from damage to the support cells (SCs) that anchors hair cells within the epithelium. To test this hypothesis, rat postnatal cochlear cultures were treated with PQ. Shortly after PQ treatment, the rows of OHCs separated from one another and migrated radially away from IHCs suggesting loss of cell-cell adhesion that hold the hair cells in proper alignment. Hair cells dislocation was associated with extensive loss of SCs in the organ of Corti, loss of tympanic border cells (TBCs) beneath the basilar membrane, the early appearance of superoxide staining and caspase-8 labeling in SCs below the OHCs and disintegration of E-cadherin and β-catenin in the organ of Corti. Damage to the TBCs and SCs occurred prior to loss of OHC or IHC loss suggesting a form of detachment-induced apoptosis referred to as anoikis.

Molecular alterations of cancer cell and tumour microenvironment in metastatic gastric cancer

The term metastasis is widely used to describe the endpoint of the process by which tumour cells spread from the primary location to an anatomically distant site. Achieving successful dissemination is dependent not only on the molecular alterations of the cancer cells themselves, but also on the microenvironment through which they encounter. Here, we reviewed the molecular alterations of metastatic gastric cancer (GC) as it reflects a large proportion of GC patients currently seen in clinic. We hope that further exploration and understanding of the multistep metastatic cascade will yield novel therapeutic targets that will lead to better patient outcomes.

The Effects of Ultrasound and Arsenic Trioxide on Neurogliocytoma Cells and Secondary Activation of Macrophages

Aims and Background

As a new technique for clinical therapeutics, ultrasound has synergistic effects on traditional chemotherapy. Arsenic trioxide (AS2O3), an apoptosis-inducing drug, has successfully been used in the treatment of some tumor types in recent years. Macrophages have both positive and negative effects on the occurrence and development of tumors. The aim of this study was to observe the effects of ultrasound and AS2O3 on a glioma cell line and the secondary activation of macrophages by cell death, in order to provide a theoretical basis for the clinical application of AS2O3 and ultrasound in glioma treatment.

Methods

Different AS2O3 concentrations were used solely or combined with ultrasound in rat glioma C6 cells to induce cell death. The degree of C6 cell death was determined by AnnexinV-FITC and PI double staining. The intracellular arsenium concentration and the release of lactate dehydrogenase (LDH) from C6 cells were also measured. The supernatant of C6 cells was then used to stimulate macrophages. Finally the activation of NF-κB and the secretion of TNF-α and TGF-β1 by macrophages were determined.

Results

The cell death increase in the group where ultrasound was used together with AS2O3 was significantly higher than that obtained by either ultrasound or AS2O3. The increase was also significantly higher than the sum of the increases in the ultrasound and the AS2O3 only groups. At the same AS2O3 concentration, additional treatment with ultrasound can significantly increase the intracellular arsenium concentration. The release of LDH from C6 cells showed a close, direct correlation with late apoptosis and necrosis, but did not exhibit an obvious correlation with early apoptosis. The activation of NF-κB and the secretion of TNF-α and TGF-β1 in macrophages also showed a close direct correlation with late apoptosis and necrosis.

Conclusions

This in vitro study demonstrates that ultrasound may synergistically enhance the cell-killing effect by promoting AS2O3 to enter the C6 cells. Macrophages may be activated by killed C6 cells, especially by necrotic C6 cells.

Herbal formula YGJDSJ inhibits anchorage-independent growth and induces anoikis in hepatocellular carcinoma Bel-7402 cells

Background

Based on clinical medications and related studies, we established a Yang-Gan Jie-Du Sang-Jie (YGJDSJ) herbal formula for hepatocarcinoma treatment. In present study, we evaluated the anti-cancer potential of YGJDSJ on suspension-grown human hepatocellular carcinoma Bel-7402 cells.

Methods

Bel-7402 cells were cultured in poly(2-hydroxyethyl methacrylate) (poly-HEMA) coated plates and treated with YGJDSJ. Anchorage-independent cell growth was detected by cell Counting Kit-8 (CCK-8) assay and soft agar colony formation assay. Anoikis was detected by ethdium homodimer-1 (EthD-1) staining and flow cytometry analysis. Caspases activities were detected by the cleavage of chromogenic substrate. Reactive oxygen species (ROS) was detected by 2′,7′-dichlorofluorescin diacetate (DCFH-DA) staining. Protein expression and phosphorylation was identified by western blot. Protein expression was knocked-down by siRNA.

Results

YGJDSJ inhibited the proliferation of Bel-7402 cells in poly-HEMA coated plates and anchorage-independent growth of Bel-7402 cells in soft agar. YGJDSJ also induced anoikis in Bel-7402 cells as indicated by EthD-1 staining and flow cytometry analysis. YGJDSJ activated caspase-3, − 8, and − 9 in suspension-grown Bel-7402 cells. The pan-caspase inhibitor Z-VAD-FMK significantly abrogated the effects of YGJDSJ on anoikis in suspension-grown Bel-7402 cells. In addition, YGJDSJ increased ROS in suspension-grown Bel-7402 cells. The ROS scavenger N-acetyl-L-cysteine (NAC) partially attenuated YGJDSJ-induced activation of caspase-3, − 8 and − 9 and anoikis in suspension-grown Bel-7402 cells. Furthermore, YGJDSJ inhibited expression and phosphorylation of protein tyrosine kinase 2 (PTK2) in suspension-grown Bel-7402 cells. Over-expression of PTK2 significantly abrogated YGJDSJ induced anoikis.

Conclusions

YGJDSJ inhibits anchorage-independent growth and induce caspase-mediated anoikis in Bel-7402 cells, and may relate to ROS generation and PTK2 downregulation.

Effects of cigarette smoke on pulmonary endothelial cells

Cigarette smoking is the leading cause of preventable disease and death in the United States. Cardiovascular comorbidities associated with both active and secondhand cigarette smoking indicate the vascular toxicity of smoke exposure. Growing evidence supports the injurious effect of cigarette smoke on pulmonary endothelial cells and the roles of endothelial cell injury in development of acute respiratory distress syndrome (ARDS), emphysema, and pulmonary hypertension. This review summarizes results from studies of humans, preclinical animal models, and cultured endothelial cells that document toxicities of cigarette smoke exposure on pulmonary endothelial cell functions, including barrier dysfunction, endothelial activation and inflammation, apoptosis, and vasoactive mediator production. The discussion is focused on effects of cigarette smoke-induced endothelial injury in the development of ARDS, emphysema, and vascular remodeling in chronic obstructive pulmonary disease.

ROS-modulated therapeutic approaches in cancer treatment

PURPOSE

Reactive oxygen species (ROS) are produced in cancer cells as a result of increased metabolic rate, dysfunction of mitochondria, elevated cell signaling, expression of oncogenes and increased peroxisome activities. Certain level of ROS is required by cancer cells, above or below which lead to cytotoxicity in cancer cells. This biochemical aspect can be exploited to develop novel therapeutic agents to preferentially and selectively target cancer cells.

METHODS

We searched various electronic databases including PubMed, Web of Science, and Google Scholar for peer-reviewed english-language articles. Selected articles ranging from research papers, clinical studies, and review articles on the ROS production in living systems, its role in cancer development and cancer treatment, and the role of microbiota in ROS-dependent cancer therapy were analyzed.

RESULTS

This review highlights oxidative stress in tumors, underlying mechanisms of different relationships of ROS and cancer cells, different ROS-mediated therapeutic strategies and the emerging role of microbiota in cancer therapy.

CONCLUSION

Cancer cells exhibit increased ROS stress and disturbed redox homeostasis which lead to ROS adaptations. ROS-dependent anticancer therapies including ROS scavenging anticancer therapy and ROS boosting anticancer therapy have shown promising results in vitro as well as in vivo. In addition, response to cancer therapy is modulated by the human microbiota which plays a critical role in systemic body functions.

Role of SIRT1/PGC-1α in mitochondrial oxidative stress in autistic spectrum disorder

Autistic spectrum disorder (ASD) is a neurodevelopmental disorder and has a high prevalence in children. Recently, mitochondrial oxidative stress has been proposed to be associated with ASD. Besides, SIRT1/PGC-1α signaling plays an important role in combating oxidative stress. In this study, we sought to determine the role of SIRT1/PGC-1α signaling in the ASD lymphoblastoid cell lines (LCLs). In this study, the mRNA and protein expressions of SIRT1/PGC-1α axis genes were assessed in 35 children with ASD and 35 healthy controls (matched for age, gender, and IQ). An immortalized LCL was established by transforming lymphocytes with Epstein-Barr virus. Next, we used ASD LCLs and control LCLs to detect SIRT1/PGC-1α axis genes expression and oxidative damage. Finally, the effect of overexpression of PGC-1α on oxidative injury in the ASD LCLs was determined. SIRT1/PGC-1α axis genes expression was downregulated at RNA and protein levels in ASD patients and LCLs. Besides, the translocation of cytochrome c and DIABLO from mitochondria to the cytosol was found in the ASD LCLs. Moreover, the intracellular reactive oxygen species (ROS) and mitochondrial ROS and cell apoptosis were increased in the ASD LCLs. However, overexpression of PGC-1α upregulated the SIRT1/PGC-1α axis genes expression and reduced cytochrome c and DIABLO release in the ASD LCLs. Also, overexpression of PGC-1α reduced the ROS generation and cell apoptosis in the ASD LCLs. Overexpression of PGC-1α could reduce the oxidative injury in the ASD LCLs, and PGC-1α may act as a target for treatment.

Emodin enhances cisplatin-induced cytotoxicity in human bladder cancer cells through ROS elevation and MRP1 downregulation

Background

Chemoresistance is one of the most leading causes for tumor progression and recurrence of bladder cancer. Reactive oxygen species (ROS) plays a key role in the chemosensitivity of cancer cells. In the present study, emodin (1,3,8-trihydroxy-6-methylanthraquinone) was applied as a ROS generator in combination with cisplatin in T24 and J82 human bladder cancer cells.

Methods

Cell viability and apoptosis rate of different treatment groups were detected by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and flow cytometry (FCM). The expression of transporters was measured at both the transcription and translation levels using PCR and western blotting. In vitro findings were confirmed by in vivo experiments using tumor-bearing mice. The expression of multidrug resistance-associated protein 1 (MRP1) in tumour tissue was measured using immunohistochemistry and side effects of the emodin/cisplatin co-treatment were investigated by histological examination.

Results

Emodin increased the cellular ROS level and effectively enhanced the cisplatin-induced cytotoxicity of T24 and J82 human bladder cancer cells through decreasing glutathione-cisplatin (GSH-cisplatin) conjugates. It blocked the chemoresistance of T24 and J82 cells to cisplatin through suppressing the expression of MRP1. This effect was specific in T24 and J82 cells but not in HCV-29 normal bladder epithelial cells. Consistent with in vitro experiments, emodin/cisplatin co-treatment increased the cell apoptosis and repressed the MRP1 expression in xenograft tumors, and without obvious systemic toxicity.

Conclusions

This study revealed that emodin could increase the cisplatin-induced cytotoxicity against T24 and J82 cells via elevating the cellular ROS level and downregulating MRP1 expression. We suggest that emodin could serve as an effective adjuvant agent for the cisplatin-based chemotherapy of bladder cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2640-3) contains supplementary material, which is available to authorized users.

IDH2 knockdown sensitizes tumor cells to emodin cytotoxicity in vitro and in vivo

Although reactive oxygen species (ROS) work as second messengers at sublethal concentrations, higher levels of ROS can kill cancer cells. Since cellular ROS levels are determined by a balance between ROS generation and removal, the combination of ROS generators, and the depletion of reducing substances greatly enhance ROS levels. Emodin (1,3,8-trihydroxy-6-methyl anthraquinone), a natural anthraquinone derivative from the root and rhizome of numerous plants, is a ROS generator that induces apoptosis in cancer cells. The major enzyme to generate mitochondrial NADPH is the mitochondrial isoenzyme of NADP⁺-dependent isocitrate dehydrogenase (IDH2). In this report, we demonstrate that IDH2 knockdown effectively enhances emodin-induced apoptosis of mouse melanoma B16F10 cells through the regulation of ROS generation. Our findings suggest that suppression of IDH2 activity results in perturbation of the cellular redox balance and, ultimately, exacerbate emodin-induced apoptotic cell death in B16F10 cells. Our results strongly support a therapeutic strategy in the management of cancer that alters the intracellular redox status by the combination of a ROS generator and the suppression of antioxidant enzyme activity.

Oxidative stress and proteasome inhibitors in multiple myeloma

Multiple myeloma is a form of plasma cell neoplasm that accounts for approximately 10% of all hematological malignancies. Recently, several novel drugs have been discovered that almost doubled the overall survival of multiple myeloma patients. One of these drugs, the first-in-class proteasome inhibitor bortezomib (Velcade) has demonstrated remarkable response rates in multiple myeloma patients, and yet, currently this disease remains incurable. The major factor undermining the success of multiple myeloma treatment is a rapidly emerging resistance to the available therapy. Thus, the development of stand-alone or adjuvant anti-myeloma agents becomes of paramount importance. Overproduction of intracellular reactive oxygen species (ROS) often accompanies malignant transformation due to oncogene activation and/or enhanced metabolism in tumor cells. As a result, these cells possess higher levels of ROS and lower levels of antioxidant molecules compared to their normal counterparts. Unbalanced production of ROS leads to oxidative stress which, if left unchecked, could be toxic for the cell. In multiple myeloma cells where high rates of immunoglobulin synthesis is an additional factor contributing to overproduction of ROS, further induction of oxidative stress can be an effective strategy to cope with this disease. Here we will review the available data on the role of oxidative stress in the cytotoxicity of proteasome inhibitors and the use of ROS-inducing compounds as anti-myeloma agents.

SENP3 regulates the global protein turnover and the Sp1 level via antagonizing SUMO2/3-targeted ubiquitination and degradation

SUMOylation is recently found to function as a targeting signal for the degradation of substrates through the ubiquitin-proteasome system. RNF4 is the most studied human SUMO-targeted ubiquitin E3 ligase. However, the relationship between SUMO proteases, SENPs, and RNF4 remains obscure. There are limited examples of the SENP regulation of SUMO2/3-targeted proteolysis mediated by RNF4. The present study investigated the role of SENP3 in the global protein turnover related to SUMO2/3-targeted ubiquitination and focused in particular on the SENP3 regulation of the stability of Sp1. Our data demonstrated that SENP3 impaired the global ubiquitination profile and promoted the accumulation of many proteins. Sp1, a cancer-associated transcription factor, was among these proteins. SENP3 increased the level of Sp1 protein via antagonizing the SUMO2/3-targeted ubiquitination and the consequent proteasome-dependent degradation that was mediated by RNF4. De-conjugation of SUMO2/3 by SENP3 attenuated the interaction of Sp1 with RNF4. In gastric cancer cell lines and specimens derived from patients and nude mice, the level of Sp1 was generally increased in parallel to the level of SENP3. These results provided a new explanation for the enrichment of the Sp1 protein in various cancers, and revealed a regulation of SUMO2/3 conjugated proteins whose levels may be tightly controlled by SENP3 and RNF4.

Antitumor Effects and Mechanism of Novel Emodin Rhamnoside Derivatives against Human Cancer Cells In Vitro

A series of novel anthracene L-rhamnopyranosides compounds were designed and synthesized and their anti-proliferative activities on cancer cell lines were investigated. We found that one derivative S-8 (EM-d-Rha) strongly inhibited cell proliferation of a panel of different human cancer cell lines including A549, HepG2, OVCAR-3, HeLa and K562 and SGC-790 cell lines, and displayed IC50 values in low micro-molar ranges, which are ten folds more effective than emodin. In addition, we found EM-d-Rha (3-(2”,3”-Di-O-acetyl-α-L-rhamnopyranosyl-(1→4)-2’,3’-di-O-acetyl-α-L-rhamnopyranosyl)-emodin) substantially induced cellular apoptosis of HepG2 and OVCAR-3 cells in the early growth stage. Furthermore, EM-d-Rha led to the decrease of mitochondrial transmembrane potential, and up-regulated the express of cells apoptosis factors in a concentration- and time-dependent manner. The results indicated the EM-d-Rha may inhibit the growth and proliferation of HepG2 cells through the pathway of apoptosis induction, and the possible molecular mechanism may due to the activation of intrinsic apoptotic signal pathway.

Mist1 Expressing Gastric Stem Cells Maintain the Normal and Neoplastic Gastric Epithelium and Are Supported by a Perivascular Stem Cell Niche

The regulation and stem cell origin of normal and neoplastic gastric glands are uncertain. Here, we show that Mist1 expression marks quiescent stem cells in the gastric corpus isthmus. Mist1(+) stem cells serve as a cell-of-origin for intestinal-type cancer with the combination of Kras and Apc mutation and for diffuse-type cancer with the loss of E-cadherin. Diffuse-type cancer development is dependent on inflammation mediated by Cxcl12(+) endothelial cells and Cxcr4(+) gastric innate lymphoid cells (ILCs). These cells form the perivascular gastric stem cell niche, and Wnt5a produced from ILCs activates RhoA to inhibit anoikis in the E-cadherin-depleted cells. Targeting Cxcr4, ILCs, or Wnt5a inhibits diffuse-type gastric carcinogenesis, providing targets within the neoplastic gastric stem cell niche.

Effect of RhoA gene silencing on proliferation and migration of gastric MGC-803 cells

In this study, the expression of silencing RhoA gene in gastric MGC-803 Cells was investigated, in order to discuss the effect of RhoA gene on cell proliferation, cell cycles and tumor migration. SiRNA sequence of RhoA gene was designed and synthesized; MGC-803 cells were transfected by Lipofectamine(TM2000). The expression of RhoA gene in mRNA and protein after interference was detected by RT-PCR and Western blot; flow cytometry was used to detect the cell cycle; cell proliferation was detected by CCK-8 assay and cell migration was detected by scratch healing assay. RhoA expression in mRNA and protein of the experimental group was significantly lower than that of the control group and blank group, and the difference was statistically significant (P < 0.05). The growth rate significantly slowed down in experimental group; the cell cycle was arrested in the G0/G1 phase and the number of cells in S-phase reduced; there was a statistically significant difference (P < 0.05). Scratch healing assay showed that cell migration of the experimental group was significantly decreased, with a statistically significant difference (P < 0.05). Specific interference on RhoA gene expression could inhibit the proliferation and migration of MGC-803 cells; therefore, siRNA sequences of RhoA gene may be an effective target for the treatment of gastric cancer.

Chemical inhibition of acetyl-CoA carboxylase suppresses self-renewal growth of cancer stem cells

Cancer stem cells (CSC) may take advantage of the Warburg effect-induced siphoning of metabolic intermediates into de novo fatty acid biosynthesis to increase self-renewal growth. We examined the anti-CSC effects of the antifungal polyketide soraphen A, a specific inhibitor of the first committed step of lipid biosynthesis catalyzed by acetyl-CoA carboxylase (ACACA). The mammosphere formation capability of MCF-7 cells was reduced following treatment with soraphen A in a dose-dependent manner. MCF-7 cells engineered to overexpress the oncogene HER2 (MCF-7/HER2 cells) were 5-fold more sensitive than MCF-7 parental cells to soraphen A-induced reductions in mammosphere-forming efficiency. Soraphen A treatment notably decreased aldehyde dehydrogenase (ALDH)-positive CSC-like cells and impeded the HER2's ability to increase the ALDH⁺-stem cell population. The following results confirmed that soraphen A-induced suppression of CSC populations occurred through ACACA-driven lipogenesis: a.) exogenous supplementation with supraphysiological concentrations of oleic acid fully rescued mammosphere formation in the presence of soraphen A and b.) mammosphere cultures of MCF-7 cells with stably silenced expression of the cytosolic isoform ACACA1, which specifically participates in de novo lipogenesis, were mostly refractory to soraphen A treatment. Our findings reveal for the first time that ACACA may constitute a previously unrecognized target for novel anti-breast CSC therapies.

Anticancer effect of 2,7-dihydroxy-3-methylanthraquinone on human gastric cancer SGC-7901 cells in vitro and in vivo

CONTEXT

2,7-Dihydroxy-3-methylanthraquinone (DDMN) is reported to have a remarkable anticancer activity against gastric cancer SGC-7901 cells.

OBJECTIVE

The objective of this study is to study the anticancer effect and mechanism of DDMN on SGC-7901 cells.

MATERIALS AND METHODS

The MTT assay was used to determine the effect of DDMN on cell viability of SGC-7901 cells, and the cytotoxic effect was evaluated by the IC50 value. After treatment with different doses of DDMN (10, 20, and 40 μM) for 48 h, flow cytometry was used to investigate the apoptosis of SGC-7901 cells induced by DDMN. Further, western blotting was performed to study anticancer mechanism by assaying apoptosis-related proteins containing Mcl-1, Bcl-xl, Bcl-2, Bax, Bak, Bad, cytochrome c, caspase-3, and caspase-9. Finally, xenograft assay was used to further evaluate the effect of DDMN on SGC-7901 cells by determining body weight of nude mice, tumor volumes, and apoptosis-related proteins.

RESULTS

These results suggest that DDMN can significantly inhibit (IC50 value = 20.92 μM) the proliferation of SGC-7901 cells and induce apoptosis of SGC-7901 cells demonstrated by flow cytometry analysis. Additionally, the results of western blotting indicated that DDMN can suppress the expression of anti-apoptotic proteins Bcl-xl and Bcl-2, increase the expression of pro-apoptotic proteins Bax, Bad (40 μM), caspase-3 and caspase-9, and evidently promote the release of cytochrome c from the mitochondria to the cytoplasm. The xenograft assay further confirmed that DDMN had significant anticancer effects on SGC-7901 cells.

CONCLUSION

DDMN had significant anticancer effect on SGC-7901 cells in vitro and in vivo related to mitochondria-mediated apoptosis.

Pharmacokinetic and Genomic Effects of Arsenite in Drinking Water on Mouse Lung in a 30-Day Exposure

The 2 objectives of this subchronic study were to determine the arsenite drinking water exposure dependent increases in female C3H mouse liver and lung tissue arsenicals and to characterize the dose response (to 0, 0.05, 0.25, 1, 10, and 85 ppm arsenite in drinking water for 30 days and a purified AIN-93M diet) for genomic mouse lung expression patterns. Mouse lungs were analyzed for inorganic arsenic, monomethylated, and dimethylated arsenicals by hydride generation atomic absorption spectroscopy. The total lung mean arsenical levels were 1.4, 22.5, 30.1, 50.9, 105.3, and 316.4 ng/g lung tissue after 0, 0.05, 0.25, 1, 10, and 85 ppm, respectively. At 85 ppm, the total mean lung arsenical levels increased 14-fold and 131-fold when compared to either the lowest noncontrol dose (0.05 ppm) or the control dose, respectively. We found that arsenic exposure elicited minimal numbers of differentially expressed genes (DEGs; 77, 38, 90, 87, and 87 DEGs) after 0.05, 0.25, 1, 10, and 85 ppm, respectively, which were associated with cardiovascular disease, development, differentiation, apoptosis, proliferation, and stress response. After 30 days of arsenite exposure, this study showed monotonic increases in mouse lung arsenical (total arsenic and dimethylarsinic acid) concentrations but no clear dose-related increases in DEG numbers.

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

The intracellular level of reactive oxygen species (ROS) is closely associated with chemosensitivity of cancer cells. Overexpression of ATP binding cassette transporter MRP1 is correlated with resistance to platinum drugs. In this study, we tested the hypothesis that emodin, a potent ROS generator, may increase sensitivity of cisplatin-(cDDP-) resistant ovarian carcinoma cells to cDDP cytotoxicity via ROS-mediated suppression of MRP1 expression. Using the isogenic pair of the human ovarian carcinoma cell line COC1 and its cDDP resistant variant COC1/DDP, we found that ROS level in the cDDP-sensitive ovarian cancer cells was significantly higher than that in the cDDP-resistant cells. Emodin enhanced ROS production in COC1/DDP cells and consequently sensitized them to cDDP-induced apoptosis. These effects were reversed by addition of the antioxidant N-acetyl-L-cysteine (NAC). Cotreatment with emodin and cDDP inhibited the tumor growth in vivo by increasing tumor cell apoptosis. The emodin-enhanced cDDP cytotoxicity was attributable to downregulation of multidrug resistance-related protein 1 (MRP1) expression. Together, these results suggest that emodin could act as an adjunct to enhance the anticancer effect of cDDP likely through ROS-related downregulation of MRP1 expression, and may be of therapeutic potential in cDDP-refractory ovarian carcinomas.

Emodin prevents hypoxic-ischemic neuronal injury: Involvement of the activin A pathway

Emodin, an extract of dried rhizomes and the root of the Rhizoma Polygoni Cuspidati, can protect neurons from hypoxic-ischemic brain damage. This study aimed to verify the underlying mechanism. After PC12 cells had differentiated into neuron-like cells under the induction of mouse nerve growth factor, cells were subjected to oxygen-glucose deprivation and treated with emodin. Results showed that the viability of neuron-like cells cultured under an ischemia-hypoxia environment decreased, while the expression of activin A and caspase-3 in cells increased. Emodin raised the survival rate of oxygen-glucose deprived neuron-like cells, increased activin A expression, and decreased caspase-3 expression. Experimental findings indicate that emodin can inhibit neuronal apoptosis and alleviate the injury of nerve cells after oxygen-glucose deprivation through the activin A pathway.

Emodin suppresses Wnt signaling in human colorectal cancer cells SW480 and SW620

Wnt signaling is involved in the regulation of cell proliferation, differentiation and apoptosis. Its aberrant activation is a key event in the pathogenesis and progression of human colorectal cancers. Dietary phytochemicals are gaining importance as chemotherapeutic agents owing to their potential to prevent, delay or reverse oncogenesis. Here we demonstrate that emodin (1,3,8-trihydroxy-6-methylanthraquinone), an anthraquinone present in the roots and bark of several medicinal plants, down regulates Wnt signaling pathway in human colorectal cancer cells (SW480 and SW620) by down regulating TCF/LEF transcriptional activity. Emodin significantly down regulated the expression of key players of Wnt signaling (β-catenin and TCF7L2) and also that of its various downstream targets (cyclin D1, c-Myc, snail, vimentin, MMP-2 and MMP-9). Two novel targets of emodin׳s action were discovered namely Wnt co-activator p300 (down regulated) and repressor HBP1 (up regulated). Morphological changes induced by emodin suggest mesenchymal to epithelial transition accompanied by the increase in E-cadherin expression in human colorectal cancer cells but a differentiation marker (alkaline phosphatase) was activated only in SW620 cells (metastatic origin) and not in SW480 cells (primary tumor-derived). Moreover, our data indicate that reactive oxygen species plays a key role in emodin-mediated down regulation of Wnt signaling as emodin-mediated inhibition of migration and induction of growth arrest were partially rescued by the reactive oxygen species scavenger ascorbic acid. Effects of emodin shown in this study may provide important insights for the use of this anthraquinone as a potential complementary and integrated medicine for the treatment of human colorectal cancer.

Cancer cell survival during detachment from the ECM: multiple barriers to tumour progression

Epithelial cells require attachment to the extracellular matrix (ECM) for survival. However, during tumour progression and metastasis, cancerous epithelial cells must adapt to and survive in the absence of ECM. During the past 20 years, several cellular changes, including anoikis, have been shown to regulate cell viability when cells become detached from the ECM. In this Opinion article, we review in detail how cancer cells can overcome or take advantage of these specific processes. Gaining a better understanding of how cancer cells survive during detachment from the ECM will be instrumental in designing chemotherapeutic strategies that aim to eliminate ECM-detached metastatic cells.