β-elemene inhibited expression of DNA methyltransferase 1 through activation of ERK1/2 and AMPKα signalling pathways in human lung cancer cells: the role of Sp1

Natural bioactive compounds targeting DNA methyltransferase enzymes in cancer: Mechanisms insights and efficiencies

The regulation of gene expression is fundamental to health and life and is essentially carried out at the promoter region of the DNA of each gene. Depending on the molecular context, this region may be accessible or non-accessible (possibility of integration of RNA polymerase or not at this region). Among enzymes that control this process, DNA methyltransferase enzymes (DNMTs), are responsible for DNA demethylation at the CpG islands, particularly at the promoter regions, to regulate transcription. The aberrant activity of these enzymes, i.e. their abnormal expression or activity, can result in the repression or overactivation of gene expression. Consequently, this can generate cellular dysregulation leading to instability and tumor development. Several reports highlighted the involvement of DNMTs in human cancers. The inhibition or activation of DNMTs is a promising therapeutic approach in many human cancers. In the present work, we provide a comprehensive and critical summary of natural bioactive molecules as primary inhibitors of DNMTs in human cancers. The active compounds hold the potential to be developed as anti-cancer epidrugs targeting DNMTs.

Antitumor Effects of β-Elemene Through Inducing Autophagy-Mediated Apoptosis in Ewing Sarcoma Family Tumor Cells

Ewing sarcoma family tumors (ESFTs) are a group of aggressive tumors mainly affecting children and young people. A compound derived from Curcuma wenyujin plant or lemon grass, β-elemene, has exhibited antitumor effects to ESFT cells, the mechanism of which remains to be clarified further. Autophagy is involved in the antitumor effects of various drugs, whereas the role of autophagy in the antitumor effects of β-elemene persists controversial. Herein we found that β-elemene treatment inhibited the viability of ESFT cells in a dose-dependent manner. The increase of LC3-II level and the decrease of p62 level were observed in β-elemene-treated cells, as well as the increase of autolysosomes, which indicated the promotion of autophagic flux. Sequentially the autophagy inhibition using 3-MA treatment or ATG5 depletion significantly reversed the viability repression and apoptosis induction by β-elemene treatment. In addition, autophagy was found to be important in the toxic effects induced by the combination treatment of β-elemene and IGF1R inhibition in ESFT cells. Our data suggested an essential role of autophagy in β-elemene-induced apoptosis in ESFT cells, which is anticipated to provide novel insights to the development of ESFT treatments.

Co-biosynthesis of germacrene A, a precursor of β-elemene, and lycopene in engineered Escherichia coli

β-Elemene is the major component of a traditional Chinese medicine (Rhizoma Curcumae) for cancer treatment, and plant extraction is the major methods currently. Biosynthesis of β-elemene is a promising and attractive route due to its advantages, including environmentally friendly processes, renewable resources, and sustainable development. In this research, biosynthesis of germacrene A, direct precursor of β-elemene, in Escherichia coli was successfully performed and 11.99 mg/L germacrene A was obtained. Thereafter, a cobiosynthesis system for germacrene A and lycopene, another kind of isoprenoid, was constructed. Furthermore, the cultivation conditions were optimized. The germacrene A production was increased to the highest level reported to date, 364.26 mg/L, threefold increase to the strain with only germacrene A production. The cobiosynthesis system was suggested to promote the metabolic flux for germacrene A production. This research enabled germacrene A production in E. coli, and it highlights the promoting mechanism of the cobiosynthesis system for two chemicals which are both belonging to isoprenoids. KEY POINTS : • Co-production of germacrene A and lycopene in E. coli. • Promoting mechanism of cobiosynthesis of two isoprenoid compounds in E. coli. • Shake-flask production of germacrene A reached to the highest 364.26 mg/L in E. coli.

Astragalus mongholicus Bunge-Curcuma aromatica Salisb. suppresses growth and metastasis of colorectal cancer cells by inhibiting M2 macrophage polarization via a Sp1/ZFAS1/miR-153-3p/CCR5 regulatory axis

Colorectal cancer (CRC) is regarded as one of the commonest cancer types around the world. Due to the poor understanding on the causes of CRC formation and progression, this study sets out to investigate the physiological mechanisms by which Astragalus mongholicus Bunge-Curcuma aromatica Salisb. (ARCR) regulates CRC growth and metastasis, and the role in which M2 macrophage polarization plays in this process. An orthotopic-transplant model of CRC was established to evaluate the influence of ARCR on the polarization of M2 macrophage and the growth and metastasis of tumors. Next, the binding affinity among Sp1, ZFAS1, miR-153-5p, and CCR5 was identified using multiple assays. Finally, after co-culture of bone marrow-derived macrophages (BMDM) with CRC cell line CT26.WT, the cell proliferative, invasive, and migrated abilities were assessed in gain- or loss-of-function experiments. ARCR inhibited the infiltration of M2 macrophages into tumor microenvironment to suppress the CRC growth and metastasis in vivo. Additionally, ARCR inhibited the transcription of ZFAS1 by reducing Sp1 expression to repress M2 macrophage polarization. Moreover, ZFAS1 competitively binds to miR-153-3p to upregulate the CCR5 expression. Finally, ARCR suppressed the polarization of M2 macrophages to inhibit the tumor growth and tumor metastasis in CRC by mediating the Sp1/ZFAS1/miR-153-3p/CCR5 regulatory axis. Collectively, ARCR appears to suppress the CRC cell growth and metastasis by suppressing M2 macrophage polarization via Sp1/ZFAS1/miR-153-3p/CCR5 regulatory axis. 1. ARCR suppress the CRC cell growth and metastasis 2. ZFAS1 promotes CCR5 expression by competitively binding to miR-153-3p. 3. Sp1 promotes M2 macrophage polarization by activating ZFAS1 via miR-153-3p/CCR5. 4. The study unveiled a protective target against CRC.

Induction of Apoptosis by Metabolites of Rhei Radix et Rhizoma (Da Huang): A Review of the Potential Mechanism in Hepatocellular Carcinoma

Liver cancer is a global disease with a high mortality rate and limited treatment options. Alternations in apoptosis of tumor cells and immune cells have become an important method for detailing the underlying mechanisms of hepatocellular carcinoma (HCC). Bcl-2 family, Caspase family, Fas and other apoptosis-related proteins have also become antagonistic targets of HCC. Da Huang (Rhei Radix et Rhizoma, RR), a traditional Chinese herb, has recently demonstrated antitumor behaviors. Multiple active metabolites of RR, including emodin, rhein, physcion, aloe-emodin, gallic acid, and resveratrol, can successfully induce apoptosis and inhibit HCC. However, the underlying mechanisms of these metabolites inhibiting the occurrence and development of HCC by inducing apoptosis is complicated owing to the multi-target and multi-pathway characteristics of traditional Chinese herbs. Accordingly, this article reviews the pathways of apoptosis, the relationship between HCC and apoptosis, the role and mechanism of apoptosis induced by mitochondrial endoplasmic reticulum pathway and death receptor pathway in HCC and the mechanism of six RR metabolites inhibiting HCC by inducing apoptosis.

Crosstalk of LncRNA HOTAIR and SP1-mediated repression of PDK1 contributes to β-Elemene-inhibited proliferation of hepatocellular carcinoma cells

ETHNOPHARMACOLOGICAL RELEVANCE

Hepatocellular carcinoma (HCC) is a liver malignancy which lacks effective treatment and has a poor prognosis. β-Elemene refers to a natural Curcuma wenyujin-derived single molecular entity, which exhibits various biological activities, and is especially well-known for it's antitumor properties.

AIM OF THE RESEARCH

LncRNA HOTAIR, SP1, and PDK1 have displayed oncogenic roles in many tumors, participating in the initiation and progression of cancers by mediating multiple signaling pathways. However, there are only a few reports about their roles and mutual relationship in the growth of HCC cells. Therefore, this study aimed to investigate the expression of LncRNA HOTAIR, SP1, and PDK1 and their interaction with β-Elemene in HCC cells.

MATERIALS AND METHODS

MTT, a Colony formation assay, and flow cytometry were employed to evaluate the growth of HCC and LO2 cells under β-Elemene. LncRNA HOTAIR, SP1 and PDK1 plasmids were transfected into HCC cells by a transient transfection assay, and the expression and interaction of LncRNA HOTAIR, SP1 and PDK1 were assessed via qRT-PCR and western blotting.

RESULTS

β-Elemene suppressed HCC cell growth through the downregulation of LncRNA HOTAIR, SP1 and PDK1. The results demonstrated a reciprocal interaction among LncRNA HOTAIR, SP1 and PDK1. Exogenous overexpression LncRNA HOTAIR or SP1 eliminated the suppressive effects of β-Elemene on them, and both of which regulated PDK1 expression in HCC cells. Additionally, exogenously overexpressed SP1 or LncRNA HOTAIR prevented β-Elemene inhibition of the protein-level expression of PDK1, whereas overexpressing PDK1 had no effect on SP1, though it still weakened the inhibition of cell growth and LncRNA HOTAIR expression by β-Elemene.

CONCLUSION

β-Elemene suppresses HCC cell proliferation via through the regulation of LncRNA HOTAIR, SP1, PDK1 and their interaction.

β-Elemene Restrains PTEN mRNA Degradation to Restrain the Growth of Lung Cancer Cells via METTL3-Mediated N6 Methyladenosine Modification

Lung cancer is one of the most fatal malignancies and the leading cause of cancer death worldwide. β-Elemene, a well-known anticancer drug, has drawn a great deal of attention from researchers attributed to its limited side impacts. N⁶-Methyladenosine (m⁶A) modification is the most common RNA modification and plays a vital role in the pathogenesis of multiple tumors. However, the functional link between β-elemene and the m⁶A modification in lung cancer development remains unexplored. In this study, we investigated whether m⁶A modification was responsible for the impacts of β-elemene on lung cancer. Firstly, outcomes suggested that β-elemene restrained the malignant behaviors of A549 together with H1299 cells. Thereafter, we observed that β-elemene markedly regulated METTL3, YTHDF1, and YTHDC1 among various m⁶A modulators. METTL3 was selected for further study because of its oncogenic function in lung cancer. RT-qRCR and western blot assays exhibited that the mRNA and protein expression levels of METTL3 were lessened by the administration of β-elemene. Mechanistically, β-elemene exerted the restrictive impacts on the cell growth of lung cancer in vivo and in vitro through targeting METTL3. More importantly, β-elemene contributed to the augmented PTEN expression via suppressing its m⁶A modification. To sum up, we provided strong clues that β-elemene promoted PTEN expression to retard lung cancer progression by the regulation of METTL3-mediated m⁶A modification.

Natural Bioactive Compounds Targeting Epigenetic Pathways in Cancer: A Review on Alkaloids, Terpenoids, Quinones, and Isothiocyanates

Cancer is one of the most complex and systemic diseases affecting the health of mankind, causing major deaths with a significant increase. This pathology is caused by several risk factors, of which genetic disturbances constitute the major elements, which not only initiate tumor transformation but also epigenetic disturbances which are linked to it and which can induce transcriptional instability. Indeed, the involvement of epigenetic disturbances in cancer has been the subject of correlations today, in addition to the use of drugs that operate specifically on different epigenetic pathways. Natural molecules, especially those isolated from medicinal plants, have shown anticancer effects linked to mechanisms of action. The objective of this review is to explore the anticancer effects of alkaloids, terpenoids, quinones, and isothiocyanates.

β-elemene inhibits non-small cell lung cancer cell migration and invasion by inactivating the FAK-Src pathway

Despite sustained effort, the prognosis of lung cancer remains poor and the therapeutic responses are limited. Cell movement ability is a prerequisite for lung cancer metastasis, which involves focal adhesion kinase (FAK)-mediated cell migration and invasion via complex formation with Src. Hence, FAK-Src signaling might be an effective target for anti-cancer treatment. β-elemene, the major component of elemene extracted from Curcuma Rhizoma, exhibits broad-spectrum anti-tumor properties. However, the role of β-elemene in lung cancer cell motility and its possible mechanism remain unknown. Herein, the role of β-elemene in the migration and invasion of two non-small cell lung cancer (NSCLC) cell lines was investigated by performing wound-healing and Transwell assays. The mRNA expression levels of genes associated with motility, including RhoA, Rac1, Cac42, matrix metalloprotease (MMP)2 and MMP9, were examined by reverse transcription-quantitative polymerase chain reaction. To determine whether β-elemene acts through FAK-Src signaling, western blotting was performed and the levels of phosphorylated FAK and Src were detected. The results indicated that β-elemene inhibited the migration and invasion of A549 and NCI-H1299 (H1299) cells, while the motility-associated genes were de-regulated following exposure to β-elemene. Furthermore, β-elemene decreased the activity of FAK and Src. Overall, these results suggest that β-elemene potentially inhibits NSCLC through FAK-Src signaling.

Preparation, characterization, pharmacokinetics and anticancer effects of PEGylated β-elemene liposomes

Objective: This study aimed to develop a new polyethylene glycol (PEG)ylated β-elemene liposome (PEG-Lipo-β-E) and evaluate its characterization, pharmacokinetics, antitumor effects and safety in vitro and in vivo.

Methods: The liposomes were prepared by ethanol injection and high-pressure micro-jet homogenization. Characterization of the liposomes was conducted, and drug content, entrapment efficiency (EE), in vitro release and stability were studied by ultra-fast liquid chromatography (UFLC) and a liquid surface method. Blood was drawn from rats to establish the pharmacokinetic parameters. The anticancer effect was evaluated in a KU-19-19 bladder cancer xenograft model. Histological analyses were performed to evaluate safety.

Results: The PEG-Lipo-β-E showed good stability and was characterized as 83.31 ± 0.181 nm in size, 0.279 ± 0.004 in polydispersity index (PDI), −21.4 ± 1.06 mV in zeta potential, 6.65 ± 0.02 in pH, 5.024 ± 0.107 mg/mL in β-elemene (β-E) content, and 95.53 ± 1.712% in average EE. The Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) indicated the formation of PEG-Lipo-β-E. Compared to elemene injection, PEG-Lipo-β-E demonstrated a 1.75-fold decrease in clearance, a 1.62-fold increase in half-life, and a 1.76-fold increase in area under the concentration-time curves (AUCs) from 0 hour to 1.5 hours (P < 0.05). PEG-Lipo-β-E also showed an enhanced anticancer effect in vivo. Histological analyses showed that there was no evidence of toxicity to the heart, kidney, liver, lung or spleen.

Conclusions: The present study demonstrates PEG-Lipo-β-E as a new formulation with ease of preparation, high EE, good stability, improved bioavailability and antitumor effects.

Beta-Elemene Reduces the Malignancy of Non-Small Cell Lung Cancer by Enhancing C3orf21 Expression

Background

Beta-elemene has potent anti-tumor effect, but its anti-tumor mechanism remains unclear. Chromosome 3 open reading frame 21 (C3orf21) acts as a tumor suppressor. This study tested whether the anti-tumor effect of beta-elemene was associated with modulating C3orf21 expression in non-small cell lung cancer (NSCLC).

Materials and Methods

The impact of beta-elemene on C3orf21 expression in NSCLC cells was quantified. The stable C3orf21 silencing A549 and over-expressing PC-9 cells were established and their effects on the beta-elemene-attenuated proliferation, wound healing and invasion of NSCLC cells as well as the expression of key regulators and signal events were determined.

Results

Beta-elemene significantly up-regulated C3orf21 expression in NSCLC cells. Beta-elemene treatment significantly attenuated the proliferation, wound healing and invasion of NSCLC cells, which were significantly mitigated by C3orf21 silencing, but enhanced by C3orf21 over-expression. Similar patterns of beta-elemene-modulated cyclinD1, c-Myc, COX2, MMP2, MMP9, VEGF, PTEN and Notch1 expression were detected in NSCLC cells.

Conclusions

Such data indicated that beta-elemene treatment attenuated the malignancy of NSCLC cells by up-regulating C3orf21 expression. Our findings may provide new mechanisms underlying the pharmacological action of beta-elemene.

Terpenoids from Curcumae Rhizoma: Their anticancer effects and clinical uses on combination and versus drug therapies

Cancer is a fatal disease with high mortality and low survival rate worldwide. At present, there is still no known cure for most cancers. Traditional Chinese medicine (TCM) represents a noteworthy reservoir for anticancer agents in drug discovery and development. Curcumae Rhizoma (called Ezhu in Chinese) is widely prescribed in TCM for anticancer therapy owing to its broad-spectrum antineoplastic activities. Especially, the terpenoids isolated from the essential oil of Curcumae Rhizoma form an integral part of cancer research and are well established as a potential anticancer agent. For example, β-elemene has been developed into a new drug for the treatment of solid tumors in China, and is currently undergoing clinical trials in the United States. The review aims to systematically summarize the recent advances on the anticancer effects and related molecular mechanisms of Curcumae Rhizoma, and its terpenoids (β-elemene, Furanodiene, Furanodienone, Germacrone, Curcumol, Curdione). In addition, we evaluated and compared the anticancer efficacy and clinical use of the terpenoids with combination therapies and traditional therapies. Therefore, this review provides sufficient evidence for the anticancer therapeutic potential of Curcumae Rhizoma and its terpenoids, and will contribute to the development of potential anticancer drugs.

Anti-Tumor Drug Discovery Based on Natural Product β-Elemene: Anti-Tumor Mechanisms and Structural Modification

Natural products are important sources for drug discovery, especially anti-tumor drugs. β-Elemene, the prominent active ingredient extract from the rhizome of Curcuma wenyujin, is a representative natural product with broad anti-tumor activities. The main molecular mechanism of β-elemene is to inhibit tumor growth and proliferation, induce apoptosis, inhibit tumor cell invasion and metastasis, enhance the sensitivity of chemoradiotherapy, regulate the immune system, and reverse multidrug resistance (MDR). Elemene oral emulsion and elemene injection were approved by the China Food and Drug Administration (CFDA) for the treatment of various cancers and bone metastasis in 1994. However, the lipophilicity and low bioavailability limit its application. To discover better β-elemene-derived anti-tumor drugs with satisfying drug-like properties, researchers have modified its structure under the premise of not damaging the basic scaffold structure. In this review, we comprehensively discuss and summarize the potential anti-tumor mechanisms and the progress of structural modifications of β-elemene.

Hypoxic tumor-derived exosomal circular RNA SETDB1 promotes invasive growth and EMT via the miR-7/Sp1 axis in lung adenocarcinoma

Hypoxia is a common feature of solid tumors and has been associated with tumor aggressiveness and poor prognosis. Exosomes are involved in mediating cellular-environment interactions. Circular RNAs (circRNAs) are a class of non-coding RNA broadly found in cells and exosomes. However, the functions and regulatory mechanisms of exosomal circRNAs induced by hypoxia remain poorly understood in lung adenocarcinoma (LUAD) development. Differentially expressed circRNAs were identified between exosomes extracted from hypoxic and normoxic conditions through microarray analysis. We focused on hsa-circ-0003439 found on chromosome 1 and derived from SET domain bifurcated histone lysine methyltransferase 1 (SETDB1), and thus we named it circSETDB1. We discovered that exosomes obtained from hypoxic LUAD cells improved the migration, invasion, and proliferation capacity of normoxic LUAD cells. circSETDB1 was found to be significantly upregulated in hypoxia-induced exosomes from LUAD cell lines compared with exosomes in the normal condition. Moreover, knockdown of circSETDB1 significantly inhibited cell malignant growth in vitro. Importantly, we showed that circSETDB1 was upregulated in serum exosomes in LUAD patients, and exosomal circSETDB1 levels were closely associated with disease stage. Finally, using RNA immunoprecipitation (RIP), bioinformatics, and luciferase reporter assays, we elucidated the implication of a circSETDB1/miR-7/specificity protein 1 (Sp1) axis in the development and epithelial-mesenchymal transition (EMT) of lung adenocarcinoma.

β-Elemene Inhibits the Proliferation and Migration of Human Glioblastoma Cell Lines via Suppressing Ring Finger Protein 135

β-Elemene is commonly used as an anti-cancer agent in different types of cancers and its effects on glioblastoma have been studied through different pathways. However, its effect through ring finger protein 135 (RNF135, OMIM 611358) (RNF135), which is upregulated in glioblastomas, has not yet been explored. The current study is focused on the effects of β-elemene on human glioblastoma cell lines U251, U118, A172 and U87 through RNF13 5. A cell counting kit-8 assay and wound healing assay have been utilized to test the proliferation and migration of the cells. Western blot and quantitative real-time-polymerase chain reaction (qRT-PCR) were used to evaluate the level of expression of RNF135. A model of nude mice was used to explore progression of the tumor in vivo. It was observed that increasing treatment time or dose of β-elemene remarkably decreased viability of the cells. The cells that were treated with β-elemene had a much lower speed of moving toward the gap in comparison to untreated cell lines. β-Elemene-treated cells showed a much lower level of expression of RNF135 mRNA than control groups (p <0.05) and the levels of RNF135 protein were lower in the cells treated with β-elemene than in control groups (p <0.05). Moreover, tumor progression in subcutaneous xenograft nude mice was delayed with the injection of β-elemene. Altogether, our findings suggest that β-elemene inhibits proliferation, migration and tumorigenicity of human glioblastoma cells through suppressing RNF135.

Stearoyl-CoA Desaturase 1 Activity Determines the Maintenance of DNMT1-Mediated DNA Methylation Patterns in Pancreatic β-Cells

Metabolic stress, such as lipotoxicity, affects the DNA methylation profile in pancreatic β-cells and thus contributes to β-cell failure and the progression of type 2 diabetes (T2D). Stearoyl-CoA desaturase 1 (SCD1) is a rate-limiting enzyme that is involved in monounsaturated fatty acid synthesis, which protects pancreatic β-cells against lipotoxicity. The present study found that SCD1 is also required for the establishment and maintenance of DNA methylation patterns in β-cells. We showed that SCD1 inhibition/deficiency caused DNA hypomethylation and changed the methyl group distribution within chromosomes in β-cells. Lower levels of DNA methylation in SCD1-deficient β-cells were followed by lower levels of DNA methyltransferase 1 (DNMT1). We also found that the downregulation of SCD1 in pancreatic β-cells led to the activation of adenosine monophosphate-activated protein kinase (AMPK) and an increase in the activity of the NAD-dependent deacetylase sirtuin-1 (SIRT1). Furthermore, the physical association between DNMT1 and SIRT1 stimulated the deacetylation of DNMT1 under conditions of SCD1 inhibition/downregulation, suggesting a mechanism by which SCD1 exerts control over DNMT1. We also found that SCD1-deficient β-cells that were treated with compound c, an inhibitor of AMPK, were characterized by higher levels of both global DNA methylation and DNMT1 protein expression compared with untreated cells. Therefore, we found that activation of the AMPK/SIRT1 signaling pathway mediates the effect of SCD1 inhibition/deficiency on DNA methylation status in pancreatic β-cells. Altogether, these findings suggest that SCD1 is a gatekeeper that protects β-cells against the lipid-derived loss of DNA methylation and provide mechanistic insights into the mechanism by which SCD1 regulates DNA methylation patterns in β-cells and T2D-relevant tissues.

Sesquiterpenes and their derivatives-natural anticancer compounds: An update

Sesquiterpenes belong to the largest group of plant secondary metabolites, which consist of three isoprene building units. These compounds are widely distributed in various angiosperms, a few gymnosperms and bryophytes. Sesquiterpenes and their allied derivatives are bio-synthesized in various plant parts including leaves, fruits and roots. These plant-based metabolites are predominantly identified in the Asteraceae family, wherein up to 5000 complexes have been documented to date. Sesquiterpenes and their derivatives are characteristically associated with plant defence mechanisms owing to their antifungal, antibacterial and antiviral activities. Over the last two decades, these compounds have been reportedly demonstrated health promoting perspectives against a wide range of metabolic syndromes i.e. hyperglycemia, hyperlipidemia, cardiovascular complications, neural disorders, diabetes, and cancer. The high potential of sesquiterpenes and their derivatives against various cancers like breast, colon, bladder, pancreatic, prostate, cervical, brain, liver, blood, ovarium, bone, endometrial, oral, lung, eye, stomach and kidney are the object of this review. Predominantly, it recapitulates the literature elucidating sesquiterpenes and their derivatives while highlighting the mechanistic approaches associated with their potent anticancer activities such as modulating nuclear factor kappa (NF-kB) activity, inhibitory action against lipid peroxidation and retarding the production of reactive oxygen & nitrogen species (ROS&RNS).

β-elemene suppresses Warburg effect in NCI-H1650 non-small-cell lung cancer cells by regulating the miR-301a-3p/AMPKα axis

β-elemene has been evidenced to suppress the development of numerous cancers including lung cancer. Previous research has found that in A549 cells, β-elemene increased the expression of adenosine monophosphate-activated protein kinase (AMPK) α (AMPKα), which negatively regulates the Warburg effect. Bioinformatics predicted that binding sites exist between AMPKα and miR-301a-3p, an miRNA that has shown oncogenic function in many cancers. The aim of this work was to investigate the effect of β-elemene on the Warburg effect in non-small-cell lung cancer (NSCLC) cells and its mechanism. Herein, the expression of miR-301a-3p was evaluated in NSCLC cells. Then, miR-301a-3p was overexpressed or silenced by mimics or inhibitors, respectively, followed by treatment with AMPK agonists or antagonists. NSCLC cells subjected to miR-301a-3p overexpression or inhibition were further treated with β-elemene. The results demonstrated that AMPKα was targeted and negatively regulated by miR-301a-3p. AMPKα agonists attenuated the Warburg effect in NSCLC cells induced by miR-301a-3p, as evidenced by the decrease in glucose level, lactic acid level, and expression of metabolism-related enzymes (glucose transporter 1 (GLUT1), hexokinase 1 (HK1), and lactate dehydrogenase A (LDHA)). Additionally, β-elemene suppressed the expression of miR-301a-3p, enhanced that of AMPKα, and inhibited the Warburg effect in NSCLC cells. The results indicated that β-elemene attenuates the Warburg effect in NSCLC cells, possibly by mediating the miR-301a-3p/AMPKα axis.

The regulation and interaction of colon cancer-associated transcript-1 and miR7-5p contribute to the inhibition of SP1 expression by solamargine in human nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a common head and neck malignancy with higher incidence in Southern China and Southeast Asia. Solamargine (SM), a steroidal alkaloid glycoside, has been shown to have anticancer properties. However, the underlying mechanism involved remains undetermined. In this study, we showed that SM inhibited the growth of NPC cells. Mechanistically, we found that solamargine decreased lncRNA colon cancer-associated transcript-1 (CCAT1) and increased miR7-5p expression. There was a reciprocal interaction of CCAT1 and miR7-5p. In addition, SM inhibited the expression of SP1 protein and promoter activity, which was strengthened by miR7-5p mimics and inhibited by overexpressed CCAT1. MiR7-5p could bind to 3'-UTR of SP1 and attenuated SP1 gene expression. Exogenously expressed SP1 feedback resisted SM-increased miR7-5p expression and more importantly reversed SM-inhibited growth of NPC cells. Finally, SM inhibited NPC tumor growth in vivo. Collectively, our results show that SM inhibits the growth of NPC cells through reciprocal regulation of CCAT1 and miR7-5p, followed by inhibition of SP1 gene expression in vitro and in vivo. The interregulation and correlation among CCAT1, miR7-5p and SP1, and the feedback regulatory loop unveil the novel molecular mechanism underlying the overall responses of SM in anti-NPC.

The regulation and interaction of PVT1 and miR181a-5p contributes to the repression of SP1 expression by the combination of XJD decoction and cisplatin in human lung cancer cells

The Chinese herbal prescription Xiaoji decoction (XJD) has been used as an adjuvant treatment of cancer for decades. However, the molecular mechanisms underlying XJD enhancement of the efficiency of chemotherapy were undetermined. In this study, we observed that combination of XJD and cisplatin (DDP) showed a greater inhibition on growth and induced a high magnitude of apoptosis in non-small cell lung cancer (NSCLC) cells. We also found that XJD decreased lncRNA PVT1 and increased miR181a-5p expressions. There was a reciprocal interaction between PVT1 and miR181a-5p. XJD decreased SP1 protein, which were overcame by overexpressed PVT1 and inhibitors of miR181a-5p. Overexpressed SP1 reversed the inhibitory effect of XJD on cell growth. Importantly, XJD and DDP exhibited synergy on regulation of PVT1, miR181a-5p, and SP1 expressions. The similar results were observed in one in vivo model. In conclusions, XJD inhibits NSCLC cell growth via reciprocal interaction of PVT1 and miR181a-5p followed by reducing SP1 expression. XJD and DDP exhibit synergy. This study provides a novel mechanism by which XJD enhances the anti-cancer effect of DDP in NSCLC cells.

β-elemene enhances cisplatin-induced apoptosis in bladder cancer cells through the ROS-AMPK signaling pathway

Cisplatin-based chemotherapy is the standard regimen for patients with bladder cancer, but its effectiveness is limited by high toxicity and the development of drug resistance. β-elemene (β-ELE), a compound extracted from Rhizoma zedoariae, has antitumor activity in various malignancies and exhibits low toxicity. However, the effects and specific mechanism of β-ELE in bladder cancer remain unclear. The present study aimed to investigate the antitumor activity and possible mechanisms of β-ELE alone and in combination with cisplatin in bladder cancer cells. Cell viability was determined using Cell Counting Kit-8. Cell cycle and reactive oxygen species (ROS) analyses were performed by flow cytometry. Apoptosis was detected by Hoechst 33258 and Annexin-V/propidium iodide staining. Mitochondrial membrane potential was determined by staining with a JC-1 probe, flow cytometry and fluorescence microscopy. Protein expression was detected by western blotting. The results revealed that β-ELE significantly inhibited the proliferation of various bladder cancer cell lines and induced cell cycle arrest at G₀/G₁-phase in T24 and 5637 cells. Compared with cisplatin alone, co-treatment with β-ELE increased cisplatin-mediated cytotoxicity against T24 cells, which resulted in the loss of mitochondrial membrane potential and release of cytochrome c into the cytoplasm. Co-treatment with β-ELE and cisplatin enhanced ROS accumulation and activation of 5′AMP-activated protein kinase (AMPK), which induced apoptosis. The results of the present study suggested that β-ELE inhibited the proliferation of bladder cancer cells in vitro and enhanced cisplatin-induced mitochondria-dependent apoptosis via the ROS-AMPK signaling pathway. Combination therapy with β-ELE requires further investigation as a potential treatment of bladder cancer.

Naturally occurring anti-cancer compounds: shining from Chinese herbal medicine

Numerous natural products originated from Chinese herbal medicine exhibit anti-cancer activities, including anti-proliferative, pro-apoptotic, anti-metastatic, anti-angiogenic effects, as well as regulate autophagy, reverse multidrug resistance, balance immunity, and enhance chemotherapy in vitro and in vivo. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2011) on the key compounds with anti-cancer effects derived from Chinese herbal medicine (curcumin, epigallocatechin gallate, berberine, artemisinin, ginsenoside Rg3, ursolic acid, silibinin, emodin, triptolide, cucurbitacin B, tanshinone I, oridonin, shikonin, gambogic acid, artesunate, wogonin, β-elemene, and cepharanthine) in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we focused on their recently discovered and/or investigated pharmacological effects, novel mechanism of action, relevant clinical studies, and their innovative applications in combined therapy and immunomodulation. In addition, the present review has extended to describe other promising compounds including dihydroartemisinin, ginsenoside Rh2, compound K, cucurbitacins D, E, I, tanshinone IIA and cryptotanshinone in view of their potentials in cancer therapy. Up to now, the evidence about the immunomodulatory effects and clinical trials of natural anti-cancer compounds from Chinese herbal medicine is very limited, and further research is needed to monitor their immunoregulatory effects and explore their mechanisms of action as modulators of immune checkpoints.

Multi-Targeting by β-Elemene and Its Anticancer Properties: A Good Choice for Oncotherapy and Radiochemotherapy Sensitization

Several studies have focused on chemical agents, tailored from natural edible products, used to prevent and treat various diseases. β-elemene is a well-known compound derived from Curcuma wenyujin that possesses a wide spectrum of anticancer properties under preclinical and clinical conditions. Several studies have demonstrated its inhibitory effect both in humans and animals with cancers. Numerous in vivo and in vitro experimental models have revealed that β-elemene can modulate multiple molecular pathways involved in carcinogenesis. In general, (1) β-elemene itself can inhibit and kill tumor cells through a variety of mechanisms, and (2) can synergistically enhance the effect of radiotherapy and/or chemotherapy, (3) also can regulate autoimmune in the treatment of tumors. In this article, we critically focused on the available scientific evidence discussing the use of β-elemene in cancer prevention, and its molecular targets and mechanisms of action in different types of cancer. In addition, we have discussed its sources, chemistry, bioavailability, and future research directions.

Reciprocal interaction of HOTAIR and SP1 together enhance the ability of Xiaoji decoction and gefitinib to inhibit EP4 expression

ETHNOPHARMACOLOGICAL RELEVANCE

The Chinese herbal prescription Xiaoji decoction (XJD) has long been used for cancer treatment. However, the molecular mechanisms underlying the effects of this medicine, particularly to enhance the efficiency of EGFR-TKI in the treatment of lung cancer have not been well elucidated.

MATERIALS AND METHODS

Cell viability and cell cycle distribution were detected by MTT assay and flow cytometry, respectively. The phosphorylation of ERK1/2 and protein levels of SP1 and EP4 were determined by Western blot. The expression of the HOX transcript antisense RNA (HOTAIR) was measured by qRT-PCR. Transient transfection experiments were used to overexpress the HOTAIR, SP1 and EP4 genes. The interaction between HOTAIR and SP1 were further examined via RNA immunoprecipitation (RIP) assay. A tumor xenograft model was used to confirm the in vitro findings.

RESULTS

We showed that XJD inhibited growth and induced cell arrest of human non-small cell lung cancer (NSCLC) cells. We also found that XJD increased the phosphorylation of ERK1/2 and inhibited levels of HOTAIR and SP1, EP4 proteins, which were blocked by inhibitor of MEK/ERK. There was reciprocal interaction between HOTAIR and SP1. Silencing of HOTAIR reduced EP4 protein levels and repressed the growth of NSCLC cells, while overexpression of HOTAIR and SP1 overcame XJD-reduced EP4 protein expression. Additionally, excessive expressed EP4 reversed the effect of XJD on cell growth. Importantly, there was synergy of XJD with another cancer treatment drug, EGFR-TKI gefitinib, in this process. We also found that XJD inhibited tumor growth in a xenograft nude mice model.

CONCLUSIONS

Our results show that XJD inhibits NSCLC cell growth via ERK1/2-mediated reciprocal repression of HOTAIR and SP1 protein expression, followed by reduced EP4 gene expression. XJD and gefitinib exhibit synergy in this process. The in vitro and in vivo study provides a novel mechanism by which XJD enhances the growth inhibitory effect of gefitinib in gefitinib-resistant NSCLC cells.

Elemene injection as adjunctive treatment to platinum-based chemotherapy in patients with stage III/IV non-small cell lung cancer: A meta-analysis following the PRISMA guidelines

BACKGROUND

Elemene injection is an anticancer Chinese patent medicine that is widely used for the treatment of advanced lung cancer. Its active ingredients are β-, γ- and δ-elemene, which are extracted from Curcumaaromatica Salisb. (Curcumawenyujin Y.H. Chen & C. Ling).

PURPOSE

To evaluate the effects of Elemene injection as adjunctive treatment to platinum-based chemotherapy (PBC) in patients with stage III/IV non-small cell lung cancer.

STUDY DESIGN

A systematic review and meta-analysis of randomized clinical trials (RCTs).

MATERIALS AND METHODS

A systematic review and meta-analysis were conducted following the PRISMA (Preferred Reported Items for Systematic Review and Meta-analysis) guidelines. Analyses were performed using Review Manager 5.3, Comprehensive Meta-Analysis 3.0 and Trial Sequential Analysis software. All RCTs comparing Elemene injection combined with PBC vs. PBC alone were selected and assessed for inclusion. The disease control rate (DCR) was defined as the primary endpoint, and the objective Response rate (ORR), survival rate, quality of life (QOL), cellular immune function and toxicities were the secondary outcomes.

RESULTS

15 RCTs recruiting 1,410 patients with stage III/IV NSCLC were included. The methodological quality of most included trials was low to moderate. Compared with PBC alone, Elemene injection plus PBC can improve DCR (RR = 1.23, 95% CI 1.16 to 1.31, p < 0.00001), ORR (RR = 1.62, 95% CI 1.44 to 1.82, p < 0.00001), 1- and 2-year survival rates (RR = 1.33, 95% CI 1.11 to 1.59, p = 0.002; RR = 1.73, 95% CI 1.21 to 2.46, p = 0.002, respectively), QOL (RR = 1.91, 95% CI 1.58 to 2.32, p < 0.00001), CD₄⁺T cell counts (WMD = 10.43, 95% CI 8.25 to 12.62, p < 0.00001), and the CD₄⁺/CD₈⁺ratio (WMD = 0.78, 95% CI 0.42 to 1.14, p < 0.0001) and can reduce severe toxicities by 58% (RR = 0.42, 95% CI 0.34 to 0.52, p < 0.00001).

CONCLUSION

Elemene injection is a safe and effective adjunctive treatment to platinum-based chemotherapy in patients with stage III/IV NSCLC. Elemene injection can improve clinical efficacy, enhance cellular immune function and alleviate the toxicity of chemotherapy. High-quality RCTs with significant survival outcomes and longer follow-ups are warranted to confirm the results further.

β-elemene inhibits radiation and hypoxia-induced macrophages infiltration via Prx-1/NF-κB/HIF-1α signaling pathway

Background: In cancers, tumor-associated macrophages (TAMs) play an important role in the progression, evasion of immunity and sensitivity to therapy. Unfortunately, radiation and hypoxia could induce the M2 macrophages infiltration and polarization. Materials and methods: In this study, we investigated the relevance of macrophage recruitment with radiation and hypoxia by transwell. We also evaluated the effect of β-elemene on the infiltration of M2 macrophages and explored its underlying molecular mechanism by a series of in vitro and in vivo experiments. Results: Irradiated or hypoxia lung cancer cells recruit macrophages, and the recruitment is MCP-1 dependent. We also found that radiation and hypoxia-induced MCP-1 secretion follows upregulation of Prx-1, which leads to nuclear accumulation of NF-κB and HIF-1α expression. In addition, β-elemene could effectively suppress this recruitment phenomenon through Prx-1/NF-κB/HIF-1α signaling. Conclusion: Our study showed that radiation and hypoxia significantly promoted the macrophages recruitment. β-elemene could effectively suppress this recruitment phenomenon and MCP-1 expression via inhibiting Prx-1/NF-κB/HIF-1α pathways.

ERα is required for suppressing OCT4-induced proliferation of breast cancer cells via DNMT1/ISL1/ERK axis

Objective

POU5F1 (OCT4) is implicated in cancer stem cell self‐renewal. Currently, some studies have shown that OCT4 has a dual function in suppressing or promoting cancer progression. However, the precise molecular mechanism of OCT4 in breast cancer progression remains unclear.

Materials and Methods

RT‐PCR and Western blot were utilized to investigate OCT4 expression in breast cancer tissues and cells. Cell proliferation assays and mouse models were applied to determine the effects of OCT4 on breast cancer cell proliferation. DNMT1 inhibitors, ChIP, CoIP, IHC and ERα inhibitors were used to explore the molecular mechanism of OCT4 in breast cancer.

Results

OCT4 was down‐regulated in breast cancer tissues, and the overexpression of OCT4 promoted MDA‐MB‐231 cell proliferation and inhibited the proliferation of MCF‐7 cells in vitro and in vivo, respectively. Two DNMT1 inhibitors (5‐aza‐dC and zebularine) suppressed OCT4‐induced MDA‐MB‐231 cell proliferation through Ras/Raf1/ERK inactivation by targeting ISL1, which is the downstream of DNMT1. In contrast, OCT4 interacted with ERα, decreased DNMT1 expression and inactivated the Ras/Raf1/ERK signalling pathway in MCF‐7 cells. Moreover, ERα inhibitor (AZD9496) reversed the suppression of OCT4‐induced proliferation in MCF‐7 cells via the activation of ERK signalling pathway.

Conclusions

OCT4 is dependent on ERα to suppress the proliferation of breast cancer cells through DNMT1/ISL1/ERK axis.

Molecular targets of β-elemene, a herbal extract used in traditional Chinese medicine, and its potential role in cancer therapy: A review

β-Elemene is a sesquiterpene compound extracted from the herb Curcuma Rhizoma and is used in traditional Chinese medicine (TCM) to treat several types of cancer, with no reported severe adverse effects. Recent studies, using in vitro and in vivo studies combined with molecular methods, have shown that β-elemene can inhibit cell proliferation, arrest the cell cycle, and induce cell apoptosis. Recent studies have identified the molecular targets of β-elemene that may have a role in cancer therapy. This review aims to discuss the anticancer potential of β-elemene through its actions on several molecular targets including kinase enzymes, transcription factors, growth factors and their receptors, and proteins. β-Elemene also regulates the expression of several key molecules that are involved in tumor angiogenesis and metastasis including vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMPs), E-cadherin, N-cadherin, and vimentin. Also, β-elemene has been shown to have regulatory effects on the immune response and increases the sensitivity of cancer cells to chemoradiotherapy and has shown effects on multidrug resistance (MDR) in malignancy. Recent studies have shown that β-elemene can induce autophagy, which prevents cancer cells from undergoing apoptosis. Therefore, the molecular mechanisms for the treatment effects on cancer of the herbal extract, β-elemene, which has been used for centuries in traditional Chinese medicine, are now being studied and identified.

Regulation of signaling pathways by β-elemene in cancer progression and metastasis

Entry of β-elemene into various phases of clinical trials advocates its significance as a premium candidate likely to gain access to mainstream medicine. Based on the insights gleaned from decades of research, it seems increasingly transparent that β-elemene has shown significant ability to modulate multiple cell signaling pathways in different cancers. We partition this multicomponent review into how β-elemene strategically modulates various signal transduction cascades. We have individually summarized regulation of tumor necrosis factor related apoptosis-inducing ligand, signal transducers and activators of transcription, transforming growth factor/SMAD, NOTCH, and mammalian target of rapamycin pathways by β-elemene. Last, we will discuss the results of clinical trials of β-elemene and how effectively we can use these findings to stratify patients who can benefit most from β-elemene.

Antitumor effects of β-elemene via targeting the phosphorylation of insulin receptor

Ewing sarcoma family tumors (ESFTs) are a group of aggressive and highly metastatic tumors lacking efficient therapies. Insulin-like growth factor 1 receptor (IGF1R) blockade is one of the most efficient targeting therapy for ESFTs. However, the appliance is obstructed by drug resistance and disease recurrence due to the activation of insulin receptor (IR) signaling induced by IGF1R blockade. Herein β-elemene, a compound derived from natural plants, exhibited a remarkable proliferation repression on ESFT cells, which was weakened by a caspase inhibitor Z-VAD. β-elemene in combination with IGF1R inhibitors enhanced markedly the repression on cellular proliferation and mTOR activation by IGF1R inhibitors and suppressed the PI3K phosphorylation induced by IGF1R inhibitors. To investigate the mechanisms, we focused on the effects of β-elemene on IR signaling pathway. β-elemene significantly suppressed the insulin-driven cell growth and the activation of mTOR and PI3K in tumor cells, while the toxicity to normal hepatocytes was much lower. Further, the phosphorylation of IR was found to be suppressed notably by β-elemene specifically in tumor cells other than normal hepatocytes. In addition, β-elemene inhibited the growth of ESFT xenografts in vivo, and the phosphorylation of IR and S6 ribosomal protein was significantly repressed in the β-elemene-treated xenografts. These data suggest that β-elemene targets IR phosphorylation to inhibit the proliferation of tumor cells specifically and enhance the effects of IGF1R inhibitors. Thus, this study provides evidence for novel approaches by β-elemene alone or in combination with IGF1R blockades in ESFTs and IR signaling hyperactivated tumors.

Non-Curcuminoids from Turmeric and Their Potential in Cancer Therapy and Anticancer Drug Delivery Formulations

Over the past decades curcuminoids have been extensively studied for their biological activities such as antiulcer, antifibrotic, antiviral, antibacterial, antiprotozoal, antimutagenic, antifertility, antidiabetic, anticoagulant, antivenom, antioxidant, antihypotensive, antihypocholesteremic, and anticancer activities. With the perception of limited toxicity and cost, these compounds forms an integral part of cancer research and is well established as a potential anticancer agent. However, only few studies have focused on the other bioactive molecules of turmeric, known as non-curcuminoids, which are also equally potent as curcuminoids. This review aims to explore the comprehensive potency including the identification, physicochemical properties, and anticancer mechanism inclusive of molecular docking studies of non-curcuminoids such as turmerones, elemene, furanodiene (FN), bisacurone, germacrone, calebin A (CA), curdione, and cyclocurcumin. An insight into the clinical studies of these curcumin-free compounds are also discussed which provides ample evidence that favors the therapeutic potential of these compounds. Like curcuminoids, limited solubility and bioavailability are the most fragile domain, which circumscribe further applications of these compounds. Thus, this review credits the encapsulation of non-curcuminoid components in diverse drug delivery systems such as co-crystals, solid lipid nanoparticles, liposomes, microspheres, polar-non-polar sandwich (PNS) technology, which help abolish their shortcomings and flaunt their ostentatious benefits as anticancer activities.

β-Elemene Synergizes With Gefitinib to Inhibit Stem-Like Phenotypes and Progression of Lung Cancer via Down-Regulating EZH2

The inhibitors for EGF receptor tyrosine kinase (EGFR-TKIs) such as gefitinib have been used as a standard treatment for non-small cell lung cancer (NSCLC), but the increasingly occurrence of drug resistance, the associated adverse effects and the enrichment of cancer stem cells significantly impedes its clinical application. β-elemene is a natural sesquiterpene with potent anti-cancer ability, and also it is renowned for its plant-origin, safety and the additive effect with traditional therapies, which prompt us to explore its potential to co-operate with TKIs to achieve greater therapeutic efficacy. Impressively, our study demonstrates that, elemene, in combination of gefitinib, displayed a significantly higher activity in inhibiting lung cancer cellular proliferation, migration and invasion. More importantly, combinative treatment profoundly impaired the epithelial to mesenchymal transition (EMT), the stem-like properties and the self-renewal capacity of lung cancer cells, and hence impeded the in vivo tumor development. We also reveal that the synergistic anti-tumor effect of elemene and gefitinib was largely mediated their regulation of enhancer of zeste homolog 2 (EZH2), an oncogenic histone methyltransferase and gene transcriptional regulator. Thus, our data indicate that combinative treatment of elemene and gefitinib has greater anti-neoplastic activity and greater efficacies in targeting cancer stem-like properties, mainly through regulating the malignant gene modifier and hence the subsequent effector molecules required for cancer progression. The findings may have potential implications for treating aggressive and resistant lung cancers.

Drug delivery systems for elemene, its main active ingredient β-elemene, and its derivatives in cancer therapy

β-elemene is a noncytotoxic Class II antitumor drug extracted from the traditional Chinese medicine Curcuma wenyujin Y. H. Chen et C. Ling. β-elemene exerts its effects by inhibiting cell proliferation, arresting the cell cycle, inducing cell apoptosis, exerting antiangiogenesis and antimetastasis effects, reversing multiple-drug resistance (MDR), and enhancing the immune system. Elemene injection and oral emulsion have been used to treat various tumors, including cancer of the lung, liver, brain, breast, ovary, gastric, prostate, and other tissues, for >20 years. The safety of both elemene injection and oral emulsion in the clinic has been discussed. Recently, the secondary development of β-elemene has attracted the attention of researchers and made great progress. On the one hand, studies have been carried out on liposome-based systems (including solid lipid nanoparticles [SLNs], nanostructured lipid carriers [NLCs], long-circulating liposomes, active targeting liposomes, and multidrug-loaded liposomes) and emulsion systems (including microemulsions, self-emulsion drug delivery systems [SEDDSs], and active targeting microemulsion) to solve the issues of poor solubility in water, low bioavailability, and severe phlebitis, as well as to improve antitumor efficacy. The pharmacokinetics of different drug delivery systems of β-elemene are also summarized. On the other hand, a number of highly active anticancer β-elemene derivatives have been obtained through modification of the structure of β-elemene. This review focuses on the two drug delivery systems and derivatives of β-elemene for cancer therapy.

Inactivation of Stat3 and crosstalk of miRNA155-5p and FOXO3a contribute to the induction of IGFBP1 expression by beta-elemene in human lung cancer

β-Elemene, an active component of natural plants, has been shown to exhibit anticancer properties. However, the detailed mechanism underlying these effects has yet to be determined. In this study, we show that β-elemene inhibits the growth of lung cancer cells. Mechanistically, we found that β-elemene decreased the phosphorylation of signal transducer and activator of transcription 3 (Stat3) and miRNA155-5p mRNA but induced the protein expression of human forkhead box class O (FOXO)3a; the latter two were abrogated in cells with overexpressed Stat3. Notably, miRNA155-5p mimics reduced FOXO3a luciferase reporter activity in the 3-UTR region and protein expression, whereas overexpressed FOXO3a countered the reduction of the miRNA155-5p levels by β-elemene. Moreover, β-elemene increased the mRNA and protein expression levels as well as promoter activity of insulin-like growth factor-binding protein 1 (IGFBP1); this finding was not observed in cells with a silenced FOXO3a gene and miRNA155-5p mimics. Finally, silencing of IGFBP1 blocked β-elemene-inhibited cell growth. Similar findings were observed in vivo. In summary, our results indicate that β-elemene increases IGFBP1 gene expression via inactivation of Stat3 followed by a reciprocal interaction between miRNA155-5p and FOXO3a. This effect leads to inhibition of human lung cancer cell growth. These findings reveal a novel molecular mechanism underlying the inhibitory effects of β-elemene on lung cancer cells.

A compound found in one Chinese medicinal herb inhibits the growth of lung cancer cells by indirectly activating a protein with anti-proliferative properties. Hann and colleagues from the Guangzhou University of Chinese Medicine, China, uncovered the molecular pathways by which β-elemene, a natural compound isolated from the Curcuma wenyujin plant, mediates the anti-cancer effects. They showed that β-elemene inactivates the two important regulatory molecules, one protein and another small RNA, while also inducing the expression of one protein that promotes in killing cancer cells. These changes lead to elevated levels of the protein that prevents cell invasion and spread. Collectively, this altered signaling inside the lung cancer cell lead to reduced growth, in both cell-based culture and mouse model. The findings help explain why β-elemene has potential as a therapeutic agent in lung cancer.

MicroRNA-133a downregulated EGFR expression in human non-small cell lung cancer cells via AKT/ERK signaling

MicroRNAs (miRNAs) may serve important roles in the regulation of human non-small cell lung cancer (NSCLC) cell growth and apoptosis. To the best of our knowledge, the present study was the first to explore the role of miRNA-133a/epidermal growth factor receptor (EGFR) in regulating NSCLC cell growth and apoptosis via the AKT/extracellular signal-regulated kinase (ERK) signaling pathway. It was determined that miRNA-133a expression was lower in NSCLC tissue than in the adjacent mucosae. Additionally, EGFR expression in the NSCLC tissue was higher compared with in the adjacent mucosae. Furthermore, the upregulation of miRNA-133a in NSCLC cells suppressed cell growth and induced apoptosis. Upregulating miRNA-133a also increased caspase-3 protein expression, while suppressing that of EGFR, phosphorylated (p)-AKT and p-ERK in NSCLC cells. Therefore, the results of the current study demonstrated that miRNA-133a downregulates EGFR expression in NSCLC via the AKT/ERK signaling pathway. These findings provide insights into the function of miRNA-133a in NSCLC, as well as into the molecular mechanisms underlying the miRNA-133a-mediated downregulation of the EGFR/AKT/ERK signaling pathway in NSCLC.

Amentoflavone induces apoptosis and suppresses glycolysis in glioma cells by targeting miR-124-3p

Malignant glioma is the most common type of brain tumor with poor clinical outcome and survival. Therefore, it is imperative to develop novel therapeutic agents for managing glioma. The aim of this study was to investigate the role of amentoflavone (AF), an active flavonoid component in Selaginella tamariscina Spring, in glioma cells and the underlying mechanism of its action. Our results showed that miR-124-3p expression was significantly down-regulated in glioma tissues relative to normal brain tissues. AF decreased cell viability and triggered apoptosis in both glioma cell lines in a dose-dependent manner. AF induced apoptosis and inhibited glycolysis in the glioma cells by upregulating miR-124-3p. Furthermore, AF upregulated miR-124-3p by repressing DNMT1 through Sp1, which in turn was caused by the activation of ROS/AMPK signaling pathway by AF. In conclusion, AF could induce apoptosis and inhibited glycolysis in glioma cells via miR-124-3p. Our findings provide preliminary experimental data that support further investigation on the therapeutic efficacy of AF in glioma.

IL-8 analogue CXCL8 (3-72) K11R/G31P, modulates LPS-induced inflammation via AKT1-NF-kβ and ERK1/2-AP-1 pathways in THP-1 monocytes

IL-8 is elevated during inflammation, and it initiates cascade of down-stream reactions. Its antagonist, CXCL8 (3-72) K11R/G31P (G31P), represses inflammatory reactions via competitive binding to CXC chemokine family, preferentially G protein-couple receptors (GPCRs) CXCR1/2. This study reports the effect of G31P on the transcription profile of lipopolysaccharide (LPS) induced inflammation in THP-1 monocytes ex-vivo. LPS (1 µg/ml) induced elevation of IL-8 was significantly reduced by G31P (20 µg/ml and 30 µg/ml), with relatively increased inhibition of CXCR2 than CXCR1. Transcription of IL-1β, IL-6, and TNF-α were significantly inhibited, while IL-10 remained relatively unchanged. G31P treatment also had repressing effect on the inflammatory associated enzymes COX-2, MMP-2, and MMP-9. Significant restriction of c-Fos, and NF-kβ mRNA expression was observed, while that of c-Jun was marginally elevated. Conversely, SP-1 mRNA expression was seen to increase appreciably by G31P treatment. While the translation of pAKT, pERK1/2, and p65- NF-kβ were down-regulated by the G31P following THP-1 cells stimulation with LPS, reactive oxygen species (ROS) expression was on the positive trajectory. Collectively, the IL-8 analogue, G31P, modulates the inflammatory profile of LPS induced inflammation in THP-1 monocytes via AKT1-NF-kβ and ERK1/2-AP-1 pathways.

Epigenetic effects of metformin: From molecular mechanisms to clinical implications

There is a growing body of evidence that links epigenetic modifications to type 2 diabetes. Researchers have more recently investigated effects of commonly used medications, including those prescribed for diabetes, on epigenetic processes. This work reviews the influence of the widely used antidiabetic drug metformin on epigenomics, microRNA levels and subsequent gene expression, and potential clinical implications. Metformin may influence the activity of numerous epigenetic modifying enzymes, mostly by modulating the activation of AMP-activated protein kinase (AMPK). Activated AMPK can phosphorylate numerous substrates, including epigenetic enzymes such as histone acetyltransferases (HATs), class II histone deacetylases (HDACs) and DNA methyltransferases (DNMTs), usually resulting in their inhibition; however, HAT1 activity may be increased. Metformin has also been reported to decrease expression of multiple histone methyltransferases, to increase the activity of the class III HDAC SIRT1 and to decrease the influence of DNMT inhibitors. There is evidence that these alterations influence the epigenome and gene expression, and may contribute to the antidiabetic properties of metformin and, potentially, may protect against cancer, cardiovascular disease, cognitive decline and aging. The expression levels of numerous microRNAs are also reportedly influenced by metformin treatment and may confer antidiabetic and anticancer activities. However, as the reported effects of metformin on epigenetic enzymes act to both increase and decrease histone acetylation, histone and DNA methylation, and gene expression, a significant degree of uncertainty exists concerning the overall effect of metformin on the epigenome, on gene expression, and on the subsequent effect on the health of metformin users.

Preliminary evaluation of the potential role of β-elemene in reversing erlotinib-resistant human NSCLC A549/ER cells

β-elemene (β-ELE) is a natural compound extracted from Curcuma zedoaria Roscoe that has shown promise as a novel anticancer drug to treat malignant tumors. Recent studies have demonstrated that β-ELE can reverse the drug resistance of tumor cells. To the best of our knowledge, there are no reports concerning the reversal of erlotinib resistance by β-ELE in human non-small cell lung cancer (NSCLC) cells. Therefore, the present study investigated the effects of β-ELE on erlotinib-resistant human NSCLC A549/ER cells in vitro and its possible mechanism of action. The sensitivity of A549/ER cells to erlotinib, the cytotoxicity of β-ELE on the growth of A549/ER cells and the effects of β-ELE on the reversal of drug resistance in A549/ER cells were determined by MTT assay. The cell apoptosis rate, cell cycle phase distribution and intracellular rhodamine 123 (Rh123) fluorescence intensity were detected by flow cytometry. The expression level of P-glycoprotein (P-gp) was detected by western blotting. A549/ER cells had a stable drug-resistance to erlotinib. β-ELE inhibited the proliferation of A549/ER cells in a time- and dose-dependent manner, enhanced the sensitivity of A549/ER cells to erlotinib and reversed the drug resistance in A549/ER cells. Treatment with 15 µg/ml β-ELE combined with 10 µmol/l erlotinib caused an increased rate of cell apoptosis and G₀/G₁ phase arrest. Furthermore, β-ELE reduced the efflux of Rh123 from A549/ER cells, increased the intracellular accumulation of Rh123 and decreased the expression of P-gp. The results of the present study indicated that β-ELE could reverse drug resistance in erlotinib-resistant human NSCLC A549/ER cells in vitro through a mechanism that may involve the decreased expression of P-gp, inhibition of P-gp dependent drug efflux and the increased intracellular concentration of anticancer drugs.

HOTAIR-mediated reciprocal regulation of EZH2 and DNMT1 contribute to polyphyllin I-inhibited growth of castration-resistant prostate cancer cells in vitro and in vivo

BACKGROUND

Polyphyllin I (PPI), one of the steroidal saponins in paris polyphylla, has been reported to exhibit antitumor effects. However, the detailed molecular mechanism underlying this has not been elucidated.

METHODS

Cell viability and cell cycle distribution were measured using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and Flow cytometry assays, respectively. Cell invasion and migration were examined by Transwell invasion and wound healing assays. Western blot analysis was performed to examine the protein expressions of zeste homolog 2 (EZH2), DNA methyltransferase 1 (DNMT1). QRT-PCR was used to examine the levels of long non-coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR). Small interfering RNAs (siRNAs) method was used to knockdown HOTAIR. Exogenously expressions of HOTAIR, DNMT1 and EZH2 were carried out by Transient transfection assays. EZH2 promoter activity was measured by Secrete-Pair Dual Luminescence Assay Kit. A nude mice xenograft model was used to confirm the findings in vitro.

RESULTS

We showed that PPI significantly inhibited growth, induced cell cycle arrest of castration-resistant prostate cancer (CRPC) cells. In addition, PPI also reduced the migration and invasion in CRPC cells. In mechanism, we found that PPI decreased the protein expressions of EZH2, DNMT1 and levels of HOTAIR. Interestingly, silenced HOTAIR reduced EZH2 and DNMT1 protein expressions. On the contrary, exogenously expressed HOTAIR resisted PPI-inhibited EZH2 and DNMT1 protein expressions, EZH2 promoter activity and cell growth. Moreover, excessive EZH2 antagonized PPI-suppressed DNMT1 protein expression or vice versa. Consistent with this, PPI inhibited tumor growth, HOTAIR, the protein expressions of DNMT1 and EZH2 in vivo.

CONCLUSION

Our results show that PPI inhibits growth of CRPC cells through inhibition of HOTAIR expression, subsequently; this results in the repression of DNMT1 and EZH2 expressions. The interactions among HOTAIR, DNMT1 and EZH2, and reciprocal regulation of DNMT1 and EZH2 contribute to the overall responses of PPI. This study reveals a novel mechanism for HOTAIR-mediated regulating DNMT1 and EZH2 in response to PPI in inhibition of the growth of CRPC cells.

β-elemene attenuates macrophage activation and proinflammatory factor production via crosstalk with Wnt/β-catenin signaling pathway

β-elemene, extracted from Rhizoma zedoariae, has been widely used as a traditional medicine for its antitumor activity against a broad range of cancers. However, the effect of β-elemene in inflammation disorders has yet to be determined. The present study was designed to investigate the anti-inflammatory effects and potential molecular mechanisms of β-elemene in lipopolysaccharide (LPS)-induced murine macrophage cells RAW264.7. We found that the production of pro-inflammatory mediators, including interleukin-6(IL-6), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), induced by LPS was significantly suppressed by β-elemene in a dose-dependent manner in RAW264.7 macrophage cell line. Also, β-elemene inhibited LPS-induced nitric oxide synthase (iNOS) and interleukin-10 (IL-10) expression by RAW264.7, which was related to the down-regulation of Wnt/β-catenin signaling pathway. Importantly, this study demonstrates that β-catenin was significantly inhibited by β-elemene, which appeared to be largely responsible for the down-regulation of Wnt/β-catenin signaling pathway. Accordingly, the deletion of β-catenin in primary macrophages reversed β-catenin-elicited inhibition of immune response. Furthermore, β-catenin expression and Wnt/β-catenin signaling pathway induced by LPS in RAW264.7 was also significantly inhibited by α-humulene, one isomeric sesquiterpene of β-elemene. α-humulene was also found to significantly inhibit LPS-induced production of proinflammatory cytokines. However, α-humulene showed more cytotoxic ability than β-elemene. Collectively, our data illustrated that β-elemene exerted a potent inhibitory effect on pro-inflammatory meditator and cytokines production via the inactivation of β-catenin, and also demonstrated the protective functions of β-elemene in endotoxin-induced inflammation. β-elemene may serve as potential nontoxic modulatory agents for the prevention and treatment of inflammatory diseases.

Cavin-1 regulates caveolae-mediated LDL transcytosis: crosstalk in an AMPK/eNOS/ NF-κB/Sp1 loop

Caveolae are specialized lipid rafts structure in the cell membrane and critical for regulating endothelial functions, e.g. transcytosis of macromolecules like low density lipoprotein (LDL) etc. Specifically, the organization and functions of caveolae are mediated by structure protein (caveolin-1) and adapter protein (cavin-1). The pathogenic role of caveolin-1 is well studied; nevertheless, mechanisms whereby cavin-1 regulates signaling transduction remain poorly understood. The aim of this study was designed to explore the role of cavin-1 in caveolae-mediated LDL transcytosis across endothelial cells. We reported here that cavin-1 knockdown mediated by small interfering RNA (siRNA) caused a significant decrease of LDL transcytosis. Moreover, cavin-1 knockdown increased the activity of endothelial nitric oxide synthase (eNOS) and the production of nitric oxide (NO). Consequently, an eNOS inhibitor, N-Nitro-L-Arginine Methyl Ester (L-NAME), not only suppressed the activity of specificity protein (Sp1) and nuclear factor kappa B (NF-κB), but also inhibited both activities via activating adenosine 5‘-monophosphate- activated protein kinase (AMPK). In conclusion, we proposed an AMPK/eNOS/NF-κB/Sp1 circuit loop was formed to regulate caveolae residing proteins’ expression, e.g. LDL receptor (LDLR), caveolin-1, eNOS, thereby to regulate caveolae-mediated LDL transcytosis in endothelial cells.

The enhancement of combination of berberine and metformin in inhibition of DNMT1 gene expression through interplay of SP1 and PDPK1

Berberine (BBR), one of active alkaloid found in the rhizome, exhibited anti‐cancer properties. We have showed that BBR inhibited growth of non‐small cell lung cancer (NSCLC) cells through mitogen‐activated protein kinase (MAPK)‐mediated increase in forkhead box O3a (FOXO3a). However, the in‐depth mechanism underlying the anti‐tumor effects still remained to be elucidated. Herein, we further confirmed that BBR not only induced cell cycle arrest, but also reduced migration and invasion of NSCLC cells. Mechanistically, we observed that BBR reduced 3‐phosphoinositide‐dependent protein kinase‐1 (PDPK1) and transcription factor SP1 protein expressions. Exogenously expressed SP1 overcame BBR‐inhibited PDPK1 expression. Moreover, BBR inhibited DNA methyltransferase 1 (DNMT1) gene expression and overexpressed DNMT1 resisted BBR‐inhibited cell growth. Intriguingly, overexpressed PDPK1 antagonized BBR‐inhibited SP1 and DNMT1 expressions. Finally, metformin enhanced the effects of BBR both in vitro and in vivo. Collectively, we observe that BBR inhibits proliferation of NSCLC cells through inhibition of SP1 and PDPK1; this results in a reduction of DNMT1 expression. The interplay of PDPK1 and SP1 contributes to the inhibition of DNMT1 in response to BBR. In addition, there is a synergy of BBR and metformin. This study uncovers a new mechanism of BBR in combination with metformin for NSCLC‐associated therapy.

Metformin ameliorates BSCB disruption by inhibiting neutrophil infiltration and MMP-9 expression but not direct TJ proteins expression regulation

Blood-spinal cord barrier (BSCB) disruption is a major process for the secondary injury of spinal cord injury (SCI) and is considered to be a therapeutic target for SCI. Previously, we demonstrated that metformin could improve functional recovery after SCI; however, the effect of metformin on BSCB is still unknown. In this study, we found that metformin could prevent the loss of tight junction (TJ) proteins at day 3 after SCI in vivo, but in vitro there was no significant difference of these proteins between control and metformin treatment in endothelial cells. This indicated that metformin-induced BSCB protection might not be mediated by up-regulating TJ proteins directly, but by inhibiting TJ proteins degradation. Thus, we investigated the role of metformin on MMP-9 and neutrophils infiltration. Neutrophils infiltration is the major source of the enhanced MMP-9 in SCI. Our results showed that metformin decreased MMP-9 production and blocked neutrophils infiltration at day 1 after injury, which might be related to ICAM-1 down-regulation. Also, our in vitro study showed that metformin inhibited TNF-α-induced MMP-9 up-regulation in neutrophils, which might be mediated via an AMPK-dependent pathway. Together, it illustrated that metformin prevented the breakdown of BSCB by inhibiting neutrophils infiltration and MMP-9 production, but not by up-regulating TJ proteins expression. Our study may help to better understand the working mechanism of metformin on SCI.

β-elemene inhibits tumor-promoting effect of M2 macrophages in lung cancer

Macrophages in tumor are mostly M2-polarized and have been reported to promote tumorigenesis, which are also defined as tumor-associated macrophages (TAMs). β-elemene has therapeutic effects against several cancers, however, it remains unknown whether β-elemene could inhibit cancer by targeting TAMs. Herein, we examined the effect of β-elemene on macrophages to elucidate a novel mechanism of β-elemene in tumor therapy. We showed that the conditioned medium of M2 macrophages promoted lung cancer cells to migration, invasion and epithelial mesenchymal transition, which could be inhibited by β-elemene. Moreover, β-elemene regulated the polarization of macrophages from M2 to M1. β-elemene also inhibited the proliferation, migration, invasion of lung cancer cells and enhanced its radiosensitivity. These results indicate β-elemene suppresses lung cancer by regulating both macrophages and lung cancer cells, it is a promising drug for combination with chemotherapy or radiotherapy.

Metformin in Lung Cancer: Review of in Vitro and in Vivo Animal Studies

Cancer cells display enhanced growth rates and a resistance to apoptosis. The ability of cancer cells to evade homeostasis and proliferate uncontrollably while avoiding programmed cell death/apoptosis is acquired through mutations to key signaling molecules, which regulate pathways involved in cell proliferation and survival and these mutations allow them to develop resistance to many chemotherapeutic agents, highlighting the need for development of new potent anti-cancer agents. Metformin has long been used as a treatment for type 2 diabetes and has recently attracted attention as a potential agent to be used in the treatment of cancer. The present review summarizes the existing in vitro and in vivo animal studies focusing on the anti-lung cancer effects of metformin and its effects on key proliferative and anti-apoptotic signaling pathways.

Anticancer effects of β-elemene with hyperthermia in lung cancer cells

β-elemene is a novel, plant-derived anticancer drug, which has been used to target multiple solid tumor types. Hyperthermia is an adjuvant therapeutic modality to treat cancer. However, the underlying mechanisms associated with the efficacy of these two treatments are largely unknown. The aim of the present study was to evaluate the effects of β-elemene combined with hyperthermia in lung cancer cell lines. An MTT assay was used to determine cell viability. The cell cycle and apoptosis were analyzed using flow cytometry. The morphology of cells during apoptosis was determined using a transmission electron microscope. The expression levels of P21, survivin, caspase-9, B-cell lymphoma 2 (Bcl-2) and Bcl-2-like protein 4 (Bax) mRNA were detected using quantitative polymerase chain reaction. β-elemene with hyperthermia treatment significantly inhibited the viability and increased the apoptosis rate of A549 cells compared with β-elemene treatment alone (P<0.01), and significantly decreased the proportion of cells in S phase compared with the control (P<0.01). Morphological observation using transmission electron microscopy indicated cross-sectional features of apoptosis: Chromatin condensation, reduced integrity of the plasma membrane, increased cellular granularity, nuclear collapse and the formation of apoptotic bodies. β-elemene with hyperthermia treatment significantly promoted P21 and Bax mRNA expression (P<0.01) and significantly decreased caspase-9, Bcl-2 and survivin mRNA expression (P<0.01) in A549 cells. In conclusion, β-elemene with hyperthermia has a significant inhibitory effect on A549 cells. This occurs through reducing S phase and inducing apoptosis, via an increase in P21 and Bax expression and a decrease in caspase-9, Bcl-2 and survivin expression.

Interplay of DNA methyltransferase 1 and EZH2 through inactivation of Stat3 contributes to β-elemene-inhibited growth of nasopharyngeal carcinoma cells

β-elemene, a compound extracted from Curcuma wenyujin plant, exhibits anticancer activity in many cancer types. However, the detailed mechanism by which β-elemene inhibits growth of nasopharyngeal carcinoma (NPC) cells remains unknown. We showed that β-elemene reduced phosphorylation of signal transducer and activator of transcription 3 (Stat3), and protein expressions of DNA methyltransferase 1 (DNMT1) and enhancer of zeste homolog 2 (EZH2). Exogenously expressed Stat3 antagonized the effect of β-elemene on DNMT1 and EZH2 expressions. Furthermore, overexpressions of DNMT1 and EZH2 reversed the effect of β-elemene on phosphorylation of Stat3 and cell growth inhibition. Intriguingly, exogenously expressed DNMT1 overcame β-elemene-inhibited EZH2 protein expression and promoter activity. On the contrary, silencing of EZH2 and DNMT1 genes feedback strengthened the effect of β-elemene on phosphorylation of Stat3. Consistent with this, β-elemene inhibited tumor growth, phosphorylation of Stat3, expressions of DNMT1 and EZH2 in a mouse xenograft model. Collectively, this study shows that β-elemene inhibits NPC cell growth via inactivation of Stat3, and reduces DNMT1 and EZH2 expressions. The interplay of DNMT1 and EZH2, and the mutual regulations among Stat3, EZH2 and DNMT1 contribute to the overall responses of β-elemene. This study uncovers a novel mechanism by which β-elemene inhibits growth of NPC cells.