Ribosome-inactivating proteins isolated from dietary bitter melon induce apoptosis and inhibit histone deacetylase-1 selectively in premalignant and malignant prostate cancer cells

The emerging role of non-coding RNAs in the Wnt/β-catenin signaling pathway in Prostate Cancer

Prostate cancer (PCa) is an important worldwide medical concern, necessitating a greater understanding of the molecular processes driving its development. The Wnt/-catenin signaling cascade is established as a central player in PCa pathogenesis, and recent research emphasizes the critical involvement of non-coding RNAs (ncRNAs) in this scenario. This in-depth study seeks to give a thorough examination of the complex relationship between ncRNAs and the Wnt/β-catenin system in PCa. NcRNAs, such as circular RNAs (circRNAs), long ncRNAs (lncRNAs), and microRNAs (miRNAs), have been recognized as essential regulators that modulate numerous facets of the Wnt/β-catenin network. MiRNAs have been recognized as targeting vital elements of the process, either enhancing or inhibiting signaling, depending on their specific roles and targets. LncRNAs participate in fine-tuning the Wnt/β-catenin network as a result of complicated interplay with both upstream and downstream elements. CircRNAs, despite being a relatively recent addition to the ncRNA family, have been implicated in PCa, influencing the Wnt/β-catenin cascade through diverse mechanisms. This article encompasses recent advances in our comprehension of specific ncRNAs that participate in the Wnt/β-catenin network, their functional roles, and clinical relevance in PCa. We investigate their use as screening and predictive indicators, and targets for treatment. Additionally, we delve into the interplay between Wnt/β-catenin and other signaling networks in PCa and the role of ncRNAs within this complex network. As we unveil the intricate regulatory functions of ncRNAs in the Wnt/β-catenin cascade in PCa, we gain valuable insights into the disease's pathogenesis. The implementation of these discoveries in practical applications holds promise for more precise diagnosis, prognosis, and targeted therapeutic approaches, ultimately enhancing the care of PCa patients. This comprehensive review underscores the evolving landscape of ncRNA research in PCa and the potential for innovative interventions in the battle against this formidable malignancy.

Unlocking the role of non-coding RNAs in prostate cancer progression: exploring the interplay with the Wnt signaling pathway

Prostate cancer (PCa) is one of the most common cancers in males, exhibiting a wide spectrum of clinical manifestations that pose challenges in its diagnosis and treatment. The Wnt signaling pathway, a conserved and complex pathway, is crucial for embryonic development, tissue homeostasis, and various physiological processes. Apart from the classical Wnt/β-catenin signaling pathway, there exist multiple non-classical Wnt signaling pathways, including the Wnt/PCP and Wnt/Ca2+ pathways. Non-coding RNAs (ncRNAs) are involved in the occurrence and development of PCa and the response to PCa treatment. ncRNAs are known to execute diverse regulatory roles in cellular processes, despite their inability to encode proteins. Among them, microRNAs, long non-coding RNAs, and circular RNAs play key roles in the regulation of the Wnt signaling pathway in PCa. Aberrant expression of these ncRNAs and dysregulation of the Wnt signaling pathway are one of the causes of cell proliferation, apoptosis, invasion, migration, and angiogenesis in PCa. Moreover, these ncRNAs affect the characteristics of PCa cells and hold promise as diagnostic and prognostic biomarkers. Herein, we summarize the role of ncRNAs in the regulation of the Wnt signaling pathway during the development of PCa. Additionally, we present an overview of the current progress in research on the correlation between these molecules and clinical features of the disease to provide novel insights and strategies for the treatment of PCa.

Investigation of cell cytotoxic activity and molecular mechanism of 5β,19-epoxycucurbita-6,23(E)-diene-3β,19(R),25-triol isolated from Momordica charantia on hepatoma cells

CONTEXT

Momordica charantia L. (Cucurbitaceae), known as bitter melon, is an edible fruit cultivated in the tropics. In this study, an active compound, 5β,19-epoxycucurbita-6,23(E)-diene-3β,19(R),25-triol (ECDT), isolated from M. charantia was investigated in regard to its cytotoxic effect on human hepatocellular carcinoma (HCC) cells.

OBJECTIVE

To examine the mechanisms of ECDT-induced apoptosis in HCC cells.

MATERIALS AND METHODS

The inhibitive activity of ECDT on HA22T HCC cells was examined by MTT assay, colony formation assay, wound healing assay, TUNEL/DAPI staining, annexin V-fluorescein isothiocyanate/propidium iodide (PI) staining and JC-1 dye. HA22T cells were treated with ECDT (5, 10, 15, 20 and 25 μM) for 24 h, and the molecular mechanism of cells apoptosis was examined by Western blot. Cells treated with vehicle DMSO were used as the negative control.

RESULTS

ECDT inhibited the cell proliferation of HA22T cells in a dose-dependent manner. Flow cytometry showed that ECDT treatment at 10-20 μM increased early apoptosis by 10-14% and late apoptosis by 2-5%. Western blot revealed that ECDT treatment activated the mitochondrial-dependent apoptotic pathway, and ECDT-induced apoptosis was mediated by the caspase signalling pathway and activation of JNK and p38MAPK. Pre-treatment of cells with MAPK inhibitors (SB203580 or SP600125) reversed the ECDT-induced cell death, which further supported the involvement of the p38MAPK and JNK pathways.

DISCUSSION AND CONCLUSIONS

Our results indicated that ECDT can induce apoptosis through the p38MAPK and JNK pathways in HA22T cells. The findings suggested that ECDT has a valuable anticancer property with the potential to be developed as a new chemotherapeutic agent for the treatment of HCC.

Tumor Endothelial Marker 8 Promotes Proliferation and Metastasis via the Wnt/β-Catenin Signaling Pathway in Lung Adenocarcinoma

Tumor endothelial marker 8 (TEM8), also known as ANTXR1, was highly expressed in cancers, and was identified as a biomarker for early diagnosis and prognosis in some cancers. However, the clinical role and molecular mechanisms of TEM8 in lung adenocarcinoma (LUAD) are still unclear. The present study aimed to explore its clinical value and the molecular mechanisms of TEM8 underlying the progression of LUAD. Our study found the elevation of TEM8 in LUAD cell lines and tissues. What’s more, we observed that the TEM8 expression level was associated with tumor size, primary tumor, and AJCC stage, and LUAD patients with high TEM8 expression usually have a poor prognosis. Then, we conducted a series of experiments by the strategy of loss-of-function and gain-of-function, and our results suggested that the knockdown of TEM8 suppressed proliferation, migration, and invasion and induced apoptosis in LUAD whereas overexpression of TEM8 had the opposite effect. Molecular mechanistic investigation showed that TEM8 exerted its promoting effects mainly through activating the Wnt/β-catenin signaling pathway. In short, our findings suggested that TEM8 played a crucial role in the progression of LUAD by activating the Wnt/β-catenin signaling pathway and could serve as a potential therapeutic target for LUAD.

Wild Bitter Melon Extract Regulates LPS-Induced Hepatic Stellate Cell Activation, Inflammation, Endoplasmic Reticulum Stress, and Ferroptosis

The activation of hepatic stellate cells (HSCs) is a key component of liver fibrosis. Two antifibrosis pathways have been identified, the reversion to quiescent-type HSCs and the clearance of HSCs through apoptosis. Lipopolysaccharide- (LPS-) induced HSCs activation and proliferation have been associated with the development of liver fibrosis. We determined the pharmacological effects of wild bitter melon (WM) on HSC activation following LPS treatment and investigated whether WM treatment affected cell death pathways under LPS-treated conditions, including ferroptosis. WM treatment caused cell death, both with and without LPS treatment. WM treatment caused reactive oxygen species (ROS) accumulation without LPS treatment and reversed the decrease in lipid ROS production in HSCs after LPS treatment. We examined the effects of WM treatment on fibrosis, endoplasmic reticulum (ER) stress, inflammation, and ferroptosis in LPS-activated HSCs. The western blotting analysis revealed that the WM treatment of LPS-activated HSCs induced the downregulation of the connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), integrin-β1, phospho-JNK (p-JNK), glutathione peroxidase 4 (GPX4), and cystine/glutamate transporter (SLC7A11) and the upregulation of CCAAT enhancer-binding protein homologous protein (CHOP). These results support WM as an antifibrotic agent that may represent a potential therapeutic solution for the management of liver fibrosis.

The apoptosis mechanisms of HepG2 cells induced by bitter melon seed

Liver cancer is one of the leading causes of cancer-related deaths in the world. Bitter melon seed (BMS) is well known for anti-inflammatory and anticancer properties. MicroRNA-421 (miR-421) is considered as a regulator of cancer initiation, tumor metastasis, and progression, interfering with transcription of the mRNAs responsible for the cancer pathogenesis. HepG2 cells were treated with BMS water extract (BMSW) for 24 hr, and the IC₅₀ was 586.27 ± 0.07 µg/ml. The ROS, mitochondrial membrane potential, the protein expression, and the nuclear fragmentation after the treatment of BMSW were respectively detected. The increase of ROS resulted in the decrease of mitochondrial membrane potential, which induced the apoptosis of cells subsequently. BMSW inhibited the proliferation of HepG2 cells by blocking cell cycle in the S phase and influenced the nuclei and the expression of protein, leading to cellular laxity and apoptosis. The expression level of miR-421 in HepG2 was distinctly down-regulated by 13.74 fold with 600 µg/ml of BMSW. Comprehensive microarray and RT-PCR analysis identified six putative target genes of miR-421 (GADD45B, DUSP6, DUSP3, DUSP10, CASP3, and CAPN2). The relationships of DUSP6, CASP3, and miR-421 were further confirmed by miR-421 mimics/inhibitor transfection by RT-PCR and western blot. The CASP3 was identified as target gene of miR-421. BMSW induced the apoptosis of HepG2 cell by regulating miR-421 and CASP3. PRACTICAL APPLICATIONS: Hepatocellular carcinoma (HCC) is a malignant tumour with the fourth highest mortality rate in the world. Bitter melon seed (BMS) as edible and medical food has significant anticancer activity. Our study indicated the anticancer mechanisms of BMS and provided the scientific basis for the application of BMS in healthy or novel functional foods. BMS can be used as dietary supplements or nutritional fortifiers to improve the survival status of patients with liver cancer due to safety and effectiveness.

Long non-coding RNA HOTAIR regulates myeloid differentiation through the upregulation of p21 via miR-17-5p in acute myeloid leukaemia

Long non-coding RNA HOTAIR has been reported to play a key role in regulating various biological processes in various cancers. However, the roles and mechanisms of HOTAIR in acute myeloid leukaemia (AML) are still unclear and need to be investigated. In this study, we induced differentiation of four AML cell lines by all-trans retinoic acid (ATRA) and found HOTAIR was significantly upregulated in the process. Chromatin immunoprecipitation (ChIP) assays indicated that C/EBPβ upregulated HOTAIR during ATRA induced differentiation in HL-60 cells. By gain- and loss-of-function analysis, we then observed that HOTAIR expression was positively correlated with ATRA-induced differentiation and negatively regulated G1 phase arrest in HL-60 cells. In addition, we found that HOTAIR promoted ATRA-induced differentiation via the regulation of the cell cycle regulator p21 via miR-17-5p. Moreover, we detected the expression of HOTAIR in 84 de novo AML patients, HOTAIR was found significantly downregulated in the AML patients compared to the iron deficiency anaemia (IDA) control group, negatively correlated with the platelet level in M2 patients. In all, our data suggest that HOTAIR may be subtype-specific in AML-M2 patients, also HOTAIR regulates AML differentiation by C/EBPBβ/HOTAIR/miR-17-5p/p21 pathway. The findings of the present study provide a novel insight into the mechanism of lncRNA-mediated differentiation and indicate that HOTAIR may be a promising therapeutic target for leukaemia, especially for AML with M2 type.Abbreviation: AML: acute myeloid leukaemia; APL: acute promyelocytic leukaemia; ATRA: all-trans retinoic acid; CCK8: cell Counting Kit-8; CDKs: cyclin-dependent kinases ; CeRNA: competing endogenous RNAs; ChIP: chromatin immunoprecipitation; CHX: cycloheximide; FAB: French-American-British; FCM: flow cytometry; HOTAIR: HOX transcript antisense RNA; IDA: iron-deficiency anemia; lncRNA: long non-coding RNA; 3'UTR: 3'untranslated region; MT: Mutation type; WT: Wild type; qRT-PCR: Quantitative real-time PCR.

Bitter Melon (Momordica Charantia), a Nutraceutical Approach for Cancer Prevention and Therapy

Cancer is the second leading cause of death worldwide. Many dietary plant products show promising anticancer effects. Bitter melon or bitter gourd (Momordica charantia) is a nutrient-rich medicinal plant cultivated in tropical and subtropical regions of many countries. Traditionally, bitter melon is used as a folk medicine and contains many bioactive components including triterpenoids, triterpene glycoside, phenolic acids, flavonoids, lectins, sterols and proteins that show potential anticancer activity without significant side effects. The preventive and therapeutic effects of crude extract or isolated components are studied in cell line-based models and animal models of multiple types of cancer. In the present review, we summarize recent progress in testing the cancer preventive and therapeutic activity of bitter melon with a focus on underlying molecular mechanisms. The crude extract and its components prevent many types of cancers by enhancing reactive oxygen species generation; inhibiting cancer cell cycle, cell signaling, cancer stem cells, glucose and lipid metabolism, invasion, metastasis, hypoxia, and angiogenesis; inducing apoptosis and autophagy cell death, and enhancing the immune defense. Thus, bitter melon may serve as a promising cancer preventive and therapeutic agent.

Emerging Antitumor Activities of the Bitter Melon (Momordica charantia)

Bitter melon or bitter gourd (Momordica charantia) is a common vegetable in Asia and it is distinctive for its bitter taste. As an ingredient in folk medicine, research from different laboratories in recent years supports its potential medicinal applications with anti-tumor, anti-diabetic, anti-HIV activities in both in vitro and animal studies. In this short review, we summarize herein the recent progress in the antitumor aspect of bitter melon with a focus on the underlying molecular mechanisms. Further mechanistic studies as well as clinical trials are necessary to further verify its medicinal applications.

Momordica charantia, a Nutraceutical Approach for Inflammatory Related Diseases

Momordica charantia, commonly called bitter melon, is a plant belonging to Cucurbitaceae family known for centuries for its pharmacological activities, and nutritional properties. Due to the presence of many bioactive compounds, some of which possess potent biological actions, this plant is used in folk medicine all over the world for the treatment of different pathologies, mainly diabetes, but also cancer, and other inflammation-associated diseases. It is widely demonstrated that M. charantia extracts contribute in lowering glycaemia in patients affected by type 2 diabetes. However, the majority of existing studies on M. charantia bioactive compounds were performed only on cell lines and in animal models. Therefore, because the real impact of bitter melon on human health has not been thoroughly demonstrated, systematic clinical studies are needed to establish its efficacy and safety in patients. Besides, both in vitro and in vivo studies have demonstrated that bitter melon may also elicit toxic or adverse effects under different conditions. The aim of this review is to provide an overview of anti-inflammatory and anti-neoplastic properties of bitter melon, discussing its pharmacological activity as well as the potential adverse effects. Even if a lot of literature is available about bitter melon as antidiabetic drug, few papers discuss the anti-inflammatory and anti-cancer properties of this plant.

Bitter gourd (Momordica charantia) as a rich source of bioactive components to combat cancer naturally: Are we on the right track to fully unlock its potential as inhibitor of deregulated signaling pathways

Research over decades has progressively explored pharmacological actions of bitter gourd (Momordica charantia). Biologically and pharmacologically active molecules isolated from M. charantia have shown significant anti-cancer activity in cancer cell lines and xenografted mice. In this review spotlight was set on the bioactive compounds isolated from M. charantia that effectively inhibited cancer development and progression via regulation of protein network in cancer cells. We summarize most recent high-quality research work in cancer cell lines and xenografted mice related to tumor suppressive role-play of M. charantia and its bioactive compounds. Although M. charantia mediated health promoting, anti-diabetic, hepatoprotective, anti-inflammatory effects have been extensively investigated, there is insufficient information related to regulation of signaling networks by bioactive molecules obtained from M. charantia in different cancers. M. charantia has been shown to modulate AKT/mTOR/p70S6K signaling, p38MAPK-MAPKAPK-2/HSP-27 pathway, cell cycle regulatory proteins and apoptosis-associated proteins in different cancers. However, still there are visible knowledge gaps related to the drug targets in different cancers because we have not yet developed comprehensive understanding of the M. charantia mediated regulation of signal transduction pathways. To explore these questions, experimental platforms are needed that can prove to be helpful in getting a step closer to personalized medicine.

Ebulin-RP, a novel member of the Ebulin gene family with low cytotoxicity as a result of deficient sugar binding domains

BACKGROUND

Sambucus ebulus is a rich source of ribosome-inactivating proteins (RIPs) and RIP-related lectins generated from multiple genes. These proteins differ in their structure, enzymatic activity and sugar binding specificity.

METHODS

We have purified and characterized ebulin-RP from S. ebulus leaves and determined the amino acid sequence by cDNA cloning. Cytotoxicity was studied in a variety of cancer cells and a comparative study of the ability of ebulin-RP to bind sugars using "in vitro" and "in silico" approaches was performed.

RESULTS

Ebulin-RP is a novel heterodimeric type 2 RIP present in S. ebulus leaves together with the type 2 RIP ebulin l, which displayed rRNA N-glycosidase activity but unlike ebulin l, lacked functional sugar binding domains. As a consequence of changes in its B-chain, ebulin-RP displayed lower cytotoxicity than ebulin l towards cancer cells and induced apoptosis as the predominant pattern of cell death.

CONCLUSIONS

Ebulin-RP is a novel member of the ebulin gene family with low cytotoxicity as a result of deficient sugar binding domains. Type 2 RIP genes from Sambucus have evolved to render proteins with different sugar affinities that may be related to different biological activities and could result in an advantage for the plant.

GENERAL SIGNIFICANCE

The ebulin family of RIPs and lectins can serve as a good model for studying the evolutionary process which may have occurred in RIPs. The lack of cytotoxicity of ebulin-RP makes it a good candidate as a toxic moiety in the construction of immunotoxins and conjugates directed against specific targets.

Momordica charantia: a popular health-promoting vegetable with multifunctionality

Products derived from edible medicinal plants have been used for centuries to prevent, treat, and even cure multiple diseases. Momordica charantia L., widely cultivated around the world, is a typical one bred for vegetables and medicinal usage. All parts of M. charantia possess important medicinal properties, including antidiabetic, anticancer, hypotensive, anti-obesity, antimicrobial, antihyperlipidemic, antioxidant, anti-inflammatory, immuno-modulatory, anthelmintic, neuro-protective, as well as hepato-protective properties both in vitro and in vivo. This review summarizes the active components and medicinal properties of M. charantia, especially the activities and mechanisms of its anti-diabetic and anti-cancer properties. The anti-diabetic properties involve inhibiting intestinal α-glucosidase and glucose transport, protecting islet β-cells, enhancing insulin secretion, increasing hepatic glucose disposal, decreasing gluconeogenesis, and even ameliorating insulin resistance. Moreover, the expressions of PPARs could also be activated and up-regulated. Meanwhile, its anticancer properties are mostly due to apoptosis, cell cycle arrest, and expression of serum factors associated with immunity. In this review, we aim to provide an overview of M. charantia and its benefits for development as a functional food.

Effect of Momordica charantia protein on proliferation, apoptosis and the AKT signal transduction pathway in the human endometrial carcinoma Ishikawa H cell line in vitro

Endometrial carcinoma (EC) is one of the most common female malignancies, and there is an urgent requirement to explore new therapeutic strategies. In the present study, Ishikawa H cells were treated with Momordica charantia protein (MCP30). The cell morphology, growth inhibition rate, cell cycle distribution, and expression of phosphate and tensin homolog, P-AKT and AKT were measured. DNA fragmentation analysis and Annexin V-fluorescein isothiocyanate/propidium iodide double staining assay were used to analyze cell apoptosis. MCP30 decreased the viability of Ishikawa H cells in a dose- and time-dependent manner. The early apoptotic rates of Ishikawa H cells treated with MCP30 at 666.67 pM reached to 16.07±0.15%, following 72 h of treatment. DNA ladder was observed in cells treated with 333.33 and 666.67 pM MCP30 following 72 h of treatment. MCP30 blocks Ishikawa H cells from progressing between the S-phase and the G2/M-phase in a time- and concentration-dependent manner. Western blotting revealed that MCP30 treatment decreased the levels of P-AKT in a dose-dependent manner. It was revealed that MCP30 decreases cell proliferation, and induces apoptosis and S-phase cell cycle arrest through the AKT signaling pathway in Ishikawa H cells.

Promise of bitter melon (Momordica charantia) bioactives in cancer prevention and therapy

Recently, there is a paradigm shift that the whole food-derived components are not 'idle bystanders' but actively participate in modulating aberrant metabolic and signaling pathways in both healthy and diseased individuals. One such whole food from Cucurbitaceae family is 'bitter melon' (Momordica charantia, also called bitter gourd, balsam apple, etc.), which has gained an enormous attention in recent years as an alternative medicine in developed countries. The increased focus on bitter melon consumption could in part be due to several recent pre-clinical efficacy studies demonstrating bitter melon potential to target obesity/type II diabetes-associated metabolic aberrations as well as its pre-clinical anti-cancer efficacy against various malignancies. The bioassay-guided fractionations have also classified the bitter melon chemical constituents based on their anti-diabetic or cytotoxic effects. Thus, by definition, these bitter melon constituents are at cross roads on the bioactivity parameters; they either have selective efficacy for correcting metabolic aberrations or targeting cancer cells, or have beneficial effects in both conditions. However, given the vast, though dispersed, literature reports on the bioactivity and beneficial attributes of bitter melon constituents, a comprehensive review on the bitter melon components and the overlapping beneficial attributes is lacking; our review attempts to fulfill these unmet needs. Importantly, the recent realization that there are common risk factors associated with obesity/type II diabetes-associated metabolic aberrations and cancer, this timely review focuses on the dual efficacy of bitter melon against the risk factors associated with both diseases that could potentially impact the course of malignancy to advanced stages. Furthermore, this review also addresses a significant gap in our knowledge regarding the bitter melon drug-drug interactions which can be predicted from the available reports on bitter melon effects on metabolism enzymes and drug transporters. This has important implications, given that a large proportion of individuals, taking bitter melon based supplements/phytochemical extracts/food based home-remedies, are also likely to be taking conventional therapeutic drugs at the same time. Accordingly, the comprehensively reviewed information here could be prudently translated to the clinical implications associated with any potential concerns regarding bitter melon consumption by cancer patients.

A new age for biomedical applications of Ribosome Inactivating Proteins (RIPs): from bioconjugate to nanoconstructs

Ribosome-inactivating proteins (RIPs) are enzymes (3.2.2.22) that possess N-glycosilase activity that irreversibly inhibits protein synthesis. RIPs have been found in plants, fungi, algae, and bacteria; their biological role is still under investigation, even if it has been recognized their role in plant defence against predators and viruses. Nevertheless, several studies on these toxins have been performed to evaluate their applicability in the biomedical field making RIPs selectively toxic towards target cells. Indeed, these molecules are extensively used to produce chimeric biomolecules, such as immunotoxins or protein/peptides conjugates. However, to date, clinical use of most of these bioconiujates has been limited by toxicity and immunogenicity. More recently, material sciences have provided a wide range of nanomaterials to be used as excellent vehicles for toxin-delivery, since they are characterized by improved stability, solubility, and in vivo pharmacokinetics. This review discusses progresses in the development of RIPs bioconjugates, with particular attention to the recent use of nanomaterials, whose appropriate design opens up a broad range of different possibilities to the use of RIPs in novel therapeutic approaches in human diseases.

Cytotoxicity mechanism of α-MMC in normal liver cells through LRP1 mediated endocytosis and JNK activation

Alpha-momorcharin (α-MMC), a type I ribosome-inactivating protein isolated from Momordica charantia, is a potential drug candidate with strong anti-tumor activity. However, α-MMC has a severe hepatotoxicity when applied in vivo, which may greatly hinders its use in clinic in the future. The biological mechanism of hepatotoxicity induced by α-MMC is largely unknown, especially the mechanism by which α-MMC enters the hepatocytes. In this study, we investigated α-MMC-induced cytotoxicity in normal liver L02 cell line as well as the mechanism underlying it. As expected, α-MMC is more toxic in L02 cells than in various normal cells from other organs. The cytotoxic effect of α-MMC on L02 cells is found to be mediated through cell apoptosis as detected by flow cytometry and fluorescence microscopy. Importantly, α-MMC was shown to bind to a specific receptor on cell membrane, as the density of the cell membrane receptor is closely related to both the amount of α-MMC endocytosed and the cytotoxicity in different cell lines. By using LRP1 competitive inhibitor α2-M or siRNA targeting LRP1, we further identified that LRP1 protein served as the membrane receptor for α-MMC. Both α2-M and siRNA targeting LRP1 can significantly inhibit α-MMC's endocytosis as well as its cytotoxicity in L02 cells. In addition, it was found that α-MMC can activate the JNK signalling pathways via LRP1 in L02 cells. As JNK activation often leads to cell apoptosis, the activation of JNK may play an important role in α-MMC-induced cytotoxicity. To our knowledge, this is the first report showing that LRP1 mediates the cytotoxicity of α-MMC through (1) endocytosis and induced apoptosis and (2) the activation of the JNK pathway. Our findings shed light on the fundamental mechanism of hepatotoxicity of α-MMC and offer reference to understand its mechanism of lymphocytotoxicity and neurotoxicity.

Histone Deacetylase Inhibitors Trichostatin A and MCP30 Relieve Benzene-Induced Hematotoxicity via Restoring Topoisomerase IIα

Dysfunction of histone acetylation inhibits topoisomerase IIα (Topo IIα), which is implicated in benzene-induced hematotoxicity in patients with chronic benzene exposure. Whether histone deacetylase (HDAC) inhibitors can relieve benzene-induced hematotoxicity remains unclear. Here we showed that hydroquinone, a main metabolite of benzene, increased the HDAC activity, decreased the Topo IIα expression and induced apoptosis in human bone marrow mononuclear cells in vitro, and treatment with two HDAC inhibitors, namely trichostatin A (TSA) or a mixture of ribosome-inactivating proteins MCP30, almost completely reversed these effects. We further established a benzene poisoning murine model by inhaling benzene vapor in a container and found that benzene poisoning decreased the expression and activity of Topo IIα, and impaired acetylation of histone H4 and H3. The analysis of regulatory factors of Topo IIα promoter found that benzene poisoning decreased the mRNA levels of SP1 and C-MYB, and increased the mRNA level of SP3. Both TSA and MCP30 significantly enhanced the acetylation of histone H3 and H4 in Topo IIα promoter and increased the expression and activity of Topo IIα in benzene poisoning mice, which contributed to relieve the symptoms of hematotoxicity. Thus, treatment with HDAC inhibitors represents an attractive approach to reduce benzene-induced hematotoxicity.

Bitter melon: a panacea for inflammation and cancer

Nature is a rich source of medicinal plants and their products that are useful for treatment of various diseases and disorders. Momordica charantia, commonly known as bitter melon or bitter gourd, is one of such plants known for its biological activities used in traditional system of medicines. This plant is cultivated in all over the world, including tropical areas of Asia, Amazon, east Africa, and the Caribbean and used as a vegetable as well as folk medicine. All parts of the plant, including the fruit, are commonly consumed and cooked with different vegetables, stir-fried, stuffed or used in small quantities in soups or beans to give a slightly bitter flavor and taste. The plant is reported to possess anti-oxidant, anti-inflammatory, anti-cancer, anti-diabetic, anti-bacterial, anti-obesity, and immunomodulatory activities. The plant extract inhibits cancer cell growth by inducing apoptosis, cell cycle arrest, autophagy and inhibiting cancer stem cells. The plant is rich in bioactive chemical constituents like cucurbitane type triterpenoids, triterpene glycosides, phenolic acids, flavonoids, essential oils, saponins, fatty acids, and proteins. Some of the isolated compounds (Kuguacin J, Karaviloside XI, Kuguaglycoside C, Momordicoside Q-U, Charantin, α-eleostearic acid) and proteins (α-Momorcharin, RNase MC2, MAP30) possess potent biological activity. In the present review, we are summarizing the anti-oxidant, anti-inflammatory, and anti-cancer activities of Momordica charantia along with a short account of important chemical constituents, providing a basis for establishing detail biological activities of the plant and developing novel drug molecules based on the active chemical constituents.

Biological activities of ribosome-inactivating proteins and their possible applications as antimicrobial, anticancer, and anti-pest agents and in neuroscience research

Ribosome-inactivating proteins (RIPs) are enzymes which depurinate ribosomal RNA (rRNA), thus impeding the process of translation resulting in inhibition of protein synthesis. They are produced by various organisms including plants, fungi and bacteria. RIPs from plants are linked to plant defense due to their antiviral, antifungal, antibacterial, and insecticidal activities in which they can be applied in agriculture to combat microbial pathogens and pests. Their anticancer, antiviral, embryotoxic, and abortifacient properties may find medicinal applications. Besides, conjugation of RIPs with antibodies or other carriers to form immunotoxins has been found useful to research in neuroscience and anticancer therapy.

Docetaxel inhibits the proliferation of non-small-cell lung cancer cells via upregulation of microRNA-7 expression

Lung cancer is the leading cause of cancer-related deaths worldwide and about 85% of these are non-small cell lung cancer (NSCLC). Several new chemotherapeutic agents have recently shown encouraging activity in NSCLC, especially docetaxel. MiRNAs (MicroRNAs) are closely related to cancer development. We studied miRNAs in NSCLC cell lines to identify those that can regulate and predict the effectiveness of docetaxel on NSCLC. CCK8, Annexin and V-FITC assays were carried out to evaluate the inhibitory effect of docetaxel on NSCLC cell lines A549 and H460, and qRT-PCR was used to detect and compare six miRNAs expression levels in the two cells with docetaxel or not. Knockdown of miR-7 by RNA interference and overexpression of miR-7 were taken to evaluate the effect of miR-7 on docetaxel effectiveness. Western blotting was used to evaluate the effect of miR-7 on Bcl2 in A549 and H460 cells. Docetaxel induced non-small cell lung cancer cell apoptosis and suppressed cell proliferation in vitro. MiR-7 expression levels were increased by docetaxel in the two cell lines. MiR-7 overexpression improved anti-proliferative and pro-apoptotic effects of docetaxel on the NSCLC cells and that miR-7 down-regulation decreased those effects. Moreover, subsequent experiments showed that BCL-2 was downregulated by miR-7 at both transcriptional and translational levels. This study further extends the biological role of miR-7 in NSCLC A549 and H460 cells and identifies BCL-2 as a novel target possibly involved in miR-7-mediated growth suppression and apoptosis induction of NSCLC cells.

Anti-tumor activities and apoptotic mechanism of ribosome-inactivating proteins

Ribosome-inactivating proteins (RIPs) belong to a family of enzymes that attack eukaryotic ribosomes and potently inhibit cellular protein synthesis. RIPs possess several biomedical properties, including anti-viral and anti-tumor activities. Multiple RIPs are known to inhibit tumor cell proliferation through inducing apoptosis in a variety of cancers, such as breast cancer, leukemia/lymphoma, and hepatoma. This review focuses on the anti-tumor activities of RIPs and their apoptotic effects through three closely related pathways: mitochondrial, death receptor, and endoplasmic reticulum pathways.

The role of dietary histone deacetylases (HDACs) inhibitors in health and disease

Modification of the histone proteins associated with DNA is an important process in the epigenetic regulation of DNA structure and function. There are several known modifications to histones, including methylation, acetylation, and phosphorylation, and a range of factors influence each of these. Histone deacetylases (HDACs) remove the acetyl group from lysine residues within a range of proteins, including transcription factors and histones. Whilst this means that their influence on cellular processes is more complex and far-reaching than histone modifications alone, their predominant function appears to relate to histones; through deacetylation of lysine residues they can influence expression of genes encoded by DNA linked to the histone molecule. HDAC inhibitors in turn regulate the activity of HDACs, and have been widely used as therapeutics in psychiatry and neurology, in which a number of adverse outcomes are associated with aberrant HDAC function. More recently, dietary HDAC inhibitors have been shown to have a regulatory effect similar to that of pharmacological HDAC inhibitors without the possible side-effects. Here, we discuss a number of dietary HDAC inhibitors, and how they may have therapeutic potential in the context of a whole food.

Restoration of miR-7 expression suppresses the growth of Lewis lung cancer cells by modulating epidermal growth factor receptor signaling

microRNAs are an abundant class of short endogenous non-coding RNAs that function as important regulators of multiple target genes and participate in diverse biological roles in carcinogenesis. However, the role of miR-7 in lung cancer remains unclear and requires further elucidation. In the present study, we found a reduction of miR-7 expression in Lewis lung cancer (3LL) cells originating from mice by real-time RT-PCR. Restoration of miR-7 inhibited 3LL cell proliferation, induced cell apoptosis in vitro and reduced tumorigenicity in vivo. We further confirmed that miR-7 downregulated the expression of both epidermal growth factor receptor (EGFR) and murine leukemia viral oncogene homologue-1 (RAF-1) oncogenes by real-time PCR and western blot analysis. Furthermore, inhibition of EGFR showed similar effects to miR-7 enforcement in 3LL cells. Taken together, these findings revealed that miR-7 acts as an antitumor miRNA in 3LL by targeting and suppressing the expression of both EGFR and RAF-1 oncogenes. This study may provide a rationale for the use of miR-7 in lung cancer target therapy.

Epigenetic modification of Nrf2 in 5-fluorouracil-resistant colon cancer cells: involvement of TET-dependent DNA demethylation

5-Fluorouracil (5-FU) is a widely used anticancer drug for the treatment of colorectal cancer (CRC). However, resistance to 5-FU often prevents the success of chemotherapy. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a transcriptional regulator and a possible target to overcome 5-FU resistance. The present study examined epigenetic changes associated with Nrf2 induction in a human CRC cell line (SNUC5) resistant to 5-FU (SNUC5/5-FUR). Nrf2 expression, nuclear translocation, and binding to promoter were higher in SNUC5/5-FUR cells than in SNUC5 cells. The activated Nrf2 in SNUC5/5-FUR cells led to an increase in the protein expression and activity of heme oxygenase-1 (HO-1), an Nrf2-regulated gene. SNUC5/5-FUR cells produced a larger amount of reactive oxygen species (ROS) than SNUC5 cells. The siRNA- or shRNA-mediated knockdown of Nrf2 or HO-1 significantly suppressed cancer cell viability and tumor growth in vitro and in vivo, resulting in enhanced 5-FU sensitivity. Methylation-specific (MS) or real-time quantitative MS-PCR data showed hypomethylation of the Nrf2 promoter CpG islands in SNUC5/5-FUR cells compared with SNUC5 cells. Expression of the DNA demethylase ten-eleven translocation (TET) was upregulated in SNUC5/5-FUR cells. ROS generated by 5-FU upregulated TET1 expression and function, whereas antioxidant had the opposite effect. These results suggested that the mechanism underlying the acquisition of 5-FU resistance in CRC involves the upregulation of Nrf2 and HO-1 expression via epigenetic modifications of DNA demethylation.

PA28gamma emerges as a novel functional target of tumour suppressor microRNA-7 in non-small-cell lung cancer

BACKGROUND

MicroRNA-7 (miR-7) has been reported to be a tumour suppressor gene. However, whether it has a role in the growth of non-small-cell lung cancer (NSCLC) and what is its target involved in the tumour growth is still under investigation.

METHODS

NSCLC tissue sample, NSCLC cell lines and tissue microarray were investigated in this study. Total RNA, miRNA and protein were used for RT-PCR and western blot analysis. Immunohistochemistry was performed in tissues microarray. Cell culture and intervention experiments were performed in vitro and in vivo. Bioinformatics prediction, western blot and luciferase assay were identified the target of miR-7.

RESULTS

In this study, we found that the expression of miR-7 was significantly downregulated not only in NSCLC cell lines, but also in human NSCLC tissues compared with the matched adjacent tissues. Restoration of its expression through miR-7 mimics in A549 and H1299 NSCLC cells inhibited cell proliferation, colony formation, and cell-cycle progression in vitro. More importantly, the tumorigenicity in nude mice was reduced after administration of miR-7 in vivo. In advance, through bioinformatic analysis, luciferase assay and western blot, we identified a novel target of miR-7, PA28gamma (a proteasome activator) to be enrolled in the regulation with tumour. PA28gamma mRNA and protein levels are markedly upregulated in NSCLC cell lines and tumour samples, exhibiting a strong inverse relation with that of miR-7. In addition, knockdown of PA28gamma induced similar effects as overexpression of miR-7 in NSCLC cells. Furthermore, miR-7 overexpression or silencing of PA28gamma reduced the cyclinD1 expression at mRNA and protein level in NSCLC cell lines.

CONCLUSION

All these findings strongly imply that the overexpression of PA28gamma resulted from miR-7 downexpression in NSCLC has an important role in promoting cancer cell progress and consequently results in NSCLC growth. Thus, strategies targeting PA28gamma and/or miR-7 may become promising molecular therapies in NSCLC treatment.

Methanolic extracts of bitter melon inhibit colon cancer stem cells by affecting energy homeostasis and autophagy

Bitter melon fruit is recommended in ancient Indian and Chinese medicine for prevention/treatment of diabetes. However its effects on cancer progression are not well understood. Here, we have determined the efficacy of methanolic extracts of bitter melon on colon cancer stem and progenitor cells. Both, whole fruit (BMW) and skin (BMSk) extracts showed significant inhibition of cell proliferation and colony formation, with BMW showing greater efficacy. In addition, the cells were arrested at the S phase of cell cycle. Moreover, BMW induced the cleavage of LC3B but not caspase 3/7, suggesting that the cells were undergoing autophagy and not apoptosis. Further confirmation of autophagy was obtained when western blots showed reduced Bcl-2 and increased Beclin-1, Atg 7 and 12 upon BMW treatment. BMW reduced cellular ATP levels coupled with activation of AMP activated protein kinase; on the other hand, exogenous additions of ATP lead to revival of cell proliferation. Finally, BMW treatment results in a dose-dependent reduction in the number and size of colonospheres. The extracts also decreased the expression of DCLK1 and Lgr5, markers of quiescent, and activated stem cells. Taken together, these results suggest that the extracts of bitter melon can be an effective preventive/therapeutic agent for colon cancer.

Differential inhibitory potencies and mechanisms of the type I ribosome inactivating protein marmorin on estrogen receptor (ER)-positive and ER-negative breast cancer cells

Breast cancer is the second most common cancer with a high incidence rate worldwide. One of the promising therapeutic approaches on breast cancer is to use the drugs that target the estrogen receptor (ER). In the present investigation, marmorin, a type I ribosome inactivating protein from the mushroom Hypsizigus marmoreus, inhibited the survival of breast cancer in vitro and in vivo. It evinced more potent cytotoxicity toward estrogen receptor (ER)-positive MCF7 breast cancer cells than ER-negative MDA-MB-231 cells. Further study disclosed that marmorin undermined the expression level of estrogen receptor α (ERα) and significantly inhibited the proliferation of MCF7 cells induced by 17β-estradiol. Knockdown of ERα in MCF7 cells significantly attenuated the inhibitory effect of marmorin on proliferation, suggesting that the ERα-mediated pathway was implicated in the suppressive action of marmorin on ER-positive breast cancer cells. Moreover, marmorin induced time-dependent apoptosis in both MCF7 and MDA-MB-231 cells. It brought about G2/M-phase arrest, mitochondrial membrane potential depolarization and caspase-9 activation in MCF7 cells, and to a lesser extent in MDA-MB-231 cells. Marmorin triggered the death receptor apoptotic pathway (e.g. caspase-8 activation) and endoplasmic reticulum stress (ERS, as evidenced by phosphorylation of PERK and IRE1α, cleavage of caspase-12, and up-regulation of CHOP expression) in both MCF7 and MDA-MB-231 cells. In summary, marmorin exhibited inhibitory effect on breast cancer partially via diminution of ERα and apoptotic pathways mediated by mitochondrial, death receptor and ERS. The results advocate that marmorin is a potential candidate for breast cancer therapy.

Momordica charantia Extract Induces Apoptosis in Human Cancer Cells through Caspase- and Mitochondria-Dependent Pathways

Plants are an invaluable source of potential new anti-cancer drugs. Momordica charantia is one of these plants with both edible and medical value and reported to exhibit anticancer activity. To explore the potential effectiveness of Momordica charantia, methanol extract of Momordica charantia (MCME) was used to evaluate the cytotoxic activity on four human cancer cell lines, Hone-1 nasopharyngeal carcinoma cells, AGS gastric adenocarcinoma cells, HCT-116 colorectal carcinoma cells, and CL1-0 lung adenocarcinoma cells, in this study. MCME showed cytotoxic activity towards all cancer cells tested, with the approximate IC₅₀ ranging from 0.25 to 0.35 mg/mL at 24 h. MCME induced cell death was found to be time-dependent in these cells. Apoptosis was demonstrated by DAPI staining and DNA fragmentation analysis using agarose gel electrophoresis. MCME activated caspase-3 and enhanced the cleavage of downstream DFF45 and PARP, subsequently leading to DNA fragmentation and nuclear condensation. The apoptogenic protein, Bax, was increased, whereas Bcl-2 was decreased after treating for 24 h in all cancer cells, indicating the involvement of mitochondrial pathway in MCME-induced cell death. These findings indicate that MCME has cytotoxic effects on human cancer cells and exhibits promising anti-cancer activity by triggering apoptosis through the regulation of caspases and mitochondria.

Cytotoxicity Analysis of Active Components in Bitter Melon (Momordica charantia) Seed Extracts Using Human Embryonic Kidney and Colon Tumor Cells

Bitter melon (Momordica charantia) seed extracts (BMSE) have been used as traditional medicine for treating various ailments, although in many cases, the active component(s) are unidentified. In this study, bitter melon seeds were extracted in water, ethanol, or ethanol: water (1:1). The aqueous seed extracts (BMSE-W) exhibited marked cytotoxicity towards human embryonic kidney 293T (HEK293T) and human colon tumor 116 (HCT116) cells. The activity in BMSE-W was unaffected by heat and proteinases treatments, and eluted in the total volume of size-exclusion HPLC, suggesting the small, organic nature of the active component(s). Gas chromatographic-mass spectrometic (GC-MS) analysis of the HPLC fractions identified methoxy-phenyl oxime (MPO) as a major active component. Acetophenone oxime, a commercially available structural homolog of MPO, demonstrated cytotoxicity comparable with that of the BMSE-W. The oxime functional group was found to be critical for activity. Increased poly-(ADP-ribose)-polymerase and β-actin cleavage, and chromatin condensation observed in treated cells suggested apoptosis as a plausible cause for the cytotoxicity. This study, for the first time, identified a cytotoxic oxime in BMSE-W.

Wnt/β-Catenin Signaling: a Promising New Target for Fibrosis Diseases

Wnt/β-catenin signaling is involved in virtually every aspect of embryonic development and also controls homeostatic self-renewal in a number of adult tissues. Recently, emerging evidence from researches of organ fibrosis suggest that sustained Wnt/β-catenin pathway reactivation is linked to the pathogenesis of fibrotic disorders. Here we focus on Wnt/β-catenin-related pathogenic effects in different organs, such as lung fibrosis, liver fibrosis, skin fibrosis and renal fibrosis. Additionally, Wnt/β-catenin signaling works in a combinatorial manner with TGF-β signaling in the process of fibrosis, and TGF-β signaling can induce expression of Wnt/β-catenin superfamily members and vice versa. Moreover, network analysis, based on pathway databases, revealed that key factors in the Wnt pathway were targeted by some differentially expressed microRNAs detected in fibrosis diseases. These findings demonstrated the crosstalks between Wnt/β-catenin pathway and TGF-β signalings, and microRNAs, highlighting the role of Wnts in organ fibrogenesis. Most importantly, nowadays there is a variety of Wnt pathway inhibitors which give us the potential therapeutic feasibility, modulation of the Wnt pathway may, therefore, present as a suitable and promising therapeutic strategy in the future.

The soybean peptide lunasin promotes apoptosis of mammary epithelial cells via induction of tumor suppressor PTEN: similarities and distinct actions from soy isoflavone genistein

Breast cancer is the leading cause of cancer deaths in women. Diet and lifestyle are major contributing factors to increased breast cancer risk. While mechanisms underlying dietary protection of mammary tumor formation are increasingly elucidated, there remains a dearth of knowledge on the nature and precise actions of specific bioactive components present in foods with purported health effects. The 43-amino acid peptide lunasin (LUN) is found in soybeans, is bioavailable similar to the isoflavone genistein (GEN), and thus may mediate the beneficial effects of soy food consumption. Here, we evaluated whether LUN displays common and distinct actions from those of GEN in non-malignant (mouse HC11) and malignant (human MCF-7) mammary epithelial cells. In MCF-7 cells, LUN up-regulated tumor suppressor phosphatase and tensin homolog deleted in chromosome ten (PTEN) promoter activity, increased PTEN transcript and protein levels and enhanced nuclear PTEN localization, similar to that shown for GEN in mammary epithelial cells. LUN-induced cellular apoptosis, akin to GEN, was mediated by PTEN, but unlike that for GEN, was p53-independent. LUN promoted E-cadherin and β-catenin non-nuclear localization similar to GEN, but unlike GEN, did not influence the proliferative effects of oncogene Wnt1 on HC11 cells. Further, LUN did not recapitulate GEN inhibitory effects on expansion of the cancer stem-like/progenitor population in MCF-7 cells. Results suggest the concerted actions of GEN and LUN on cellular apoptosis for potential mammary tumor preventive effects and highlight whole food consumption rather than intake of specific dietary supplements with limited biological effects for greater health benefits.

Distinct cellular responses induced by saporin and a transferrin-saporin conjugate in two different human glioblastoma cell lines

Glioblastoma multiforme (GBM) is the most common primary brain tumour in adults, with a median survival of ~12-18 months post-diagnosis. GBM usually recurs within 12 months post-resection, with poor prognosis. Thus, novel therapeutic strategies to target and kill GBM cells are urgently needed. The marked difference of tumour cells with respect to normal brain cells renders glioblastoma a good candidate for selective targeted therapies. Recent experimental strategies focus on over expressed cell surface receptors. Targeted toxins represent a new class of selective molecules composed by a potent protein toxin and a carrier ligand. Targeted toxins approaches against glioblastoma were under investigation in phase I and II clinical trials with several immunotoxins (IT)/ligand toxins such as IL4-Pseudomonas aeruginosa exotoxin A (IL4-PE, NBI-3001), tumour growth factor fused to PE38, a shorter PE variant, (TGF)alpha-TP-38, IL13-PE38, and a transferrin-C diphtheriae toxin mutant (Tf-CRM107). In this work, we studied the effects of the plant ribosome-inactivating saporin and of its chimera transferrin-saporin against two different GBM cell lines. The data obtained here indicate that cell proliferation is affected by the toxin treatments but that different mechanisms are used, directly linked to the presence of an active or inactive p53. A model is proposed for these alternative intracellular pathways.

In vitro and in vivo anticarcinogenic effects of RNase MC2, a ribonuclease isolated from dietary bitter gourd, toward human liver cancer cells

Hepatocellular carcinoma (HCC) constitutes a predominant part of primary liver cancer which ranks as the fifth most common cancer as well as the third most common cause of cancer mortality. In view of the poor prognosis of unresectable liver cancers, it is of pivotal importance to develop novel chemotherapeutical regimens. RNase MC2 is a 14-kDa ribonuclease isolated from dietary bitter gourd (Momordica charantia) that manifested antitumor potential against breast cancers. In this study, we investigated the potential application of RNase MC2 on Hep G2 cells. We showed that RNase MC2 inhibited cell proliferation and induced cell apoptosis in both in vitro and in vivo studies. RNase MC2 treatment caused cell cycle arrest predominantly at the S-phase and apoptosis, which is associated with the activation of both caspase-8 and caspase-9 regulated caspase pathways. Our further investigation disclosed that RNase MC2 down-regulated the anti-apoptotic protein Bcl-2 and increased the expression of pro-apoptotic protein Bak. Moreover, the phosphorylation of ERK and JNK was involved in the apoptosis process. Importantly, RNase MC2 significantly suppressed the growth of Hep G2 xenograft-bearing nude mice by inducing apoptosis. This notion is supported by data indicating an increased number of caspase-3- and PARP-positive cells, and TUNEL-positive cells in RNase MC2-treated tumor tissues. In summary, we have revealed the antitumor potential of RNase MC2 toward Hep G2 cells. Considering that bitter gourd is a common dietary component in many countries, this study may help to prompt the clinical application of RNase MC2.

Glucocorticoids inhibit lipopolysaccharide-mediated inflammatory response by downregulating microRNA-155: a novel anti-inflammation mechanism

Glucocorticoids (GCs) are among the most widely used and effective therapies for many chronic inflammatory diseases. Although attempts have been made to identify important protein-coding genes and pathways involved in the anti-inflammatory effect of GCs, knowledge of genomic aberrations associated with noncoding genes, such as micro-RNAs (miRNAs), and their contributions is relatively limited. In this study, a systematic screening of the miRNA expression profile by microarray showed that GCs inhibited the expression of miR-155 in lipopolysaccharide (LPS)-induced macrophage inflammatory responses. Overexpression of miR-155 markedly reversed the suppressive action of GCs, whereas inhibition of miR-155 exhibited an effect similar to that of GCs on LPS-treated RAW264.7 cells, indicating miR-155 to be a functional regulator in the anti-inflammatory effect of GCs. Furthermore, GCs inhibited miR-155 expression in a GC receptor- and NF-κB-dependent manner. Bioinformatics analysis and luciferase assay revealed that the NF-κB binding site located in the promoter region of the B-cell integration cluster was important in mediating the GC-driven suppression of miR-155 in response to LPS stimulation. In addition, the combination of treatment with GCs and inhibition of miR-155 enhanced the anti-inflammatory effect of GCs on LPS-stimulated RAW264.7 cells. Therefore, we identify miR-155 to be a novel target through which GCs exert their anti-inflammatory effect on the LPS-induced macrophage inflammatory response. These findings may provide a basic rationale for new approaches in the effort to develop anti-inflammatory therapeutics.