?-Elemene Selectively Inhibits the Proliferation of Glioma Stem-Like Cells Through the Downregulation of Notch1.
ABSTRACT: Glioma is the most frequent primary central nervous system tumor. Although the current first-line medicine, temozolomide (TMZ), promotes patient survival, drug resistance develops easily. Thus, it is important to investigate novel therapeutic reagents to solidify the treatment effect. ?-Elemene (bELE) is a compound from a Chinese herb whose anticancer effect has been shown in various types of cancer. However, its role in the inhibition of glioma stem-like cells (GSLCs) has not yet been reported. We studied both the in vitro and the in vivo inhibitory effect of bELE and TMZ in GSLCs and parental cells and their combined effects. The molecular mechanisms were also investigated. We also optimized the delivery methods of bELE. We found that bELE selectively inhibits the proliferation and sphere formation of GSLCs, other than parental glioma cells, and TMZ exerts its effects on parental cells instead of GSLCs. The in vivo data confirmed that the combination of bELE and TMZ worked better in the xenografts of GSLCs, mimicking the situation of tumorigenesis of human cancer. Notch1 was downregulated with bELE treatment. Our data also demonstrated that the continuous administration of bELE produces an ideal effect to control tumor progression. Our findings have demonstrated, for the first time, that bELE could compensate for TMZ to kill both GSLCs and nonstem-like cancer cells, probably improving the prognosis of glioma patients tremendously. Notch1 might be a downstream target of bELE. Therefore, our data shed light on improving the outcomes of glioma patients by combining bELE and TMZ. Stem Cells Translational Medicine 2017;6:830-839.
Project description:?-elemene, a Curcuma wenyujin plant extract, has been used widely as a tumor adjuvant therapeutic agent. However, how to obtain optimum therapeutic effects by combining this compound with other agents remain unclear. In this study, we found that ?-elemene, which alone had little effect on hepatocellular carcinoma (HCC) cell proliferation, exerted a synergistic anti-proliferative effect in HCC cells when dosed in combination with oxaliplatin, which increased the amounts of platinum accumulation and platinum-DNA adduct significantly and augmented the oxaliplatin-induced apoptosis. Western blot and laser scanning confocal microscopy studies indicated that ?-elemene enhanced the sensitivity of HCC cells to oxaliplatin by upregulating copper transporter 1 (CTR1), a major controller of intracellular platinum accumulation. In an orthotopic transplantation HCC model in nude mice, HCC tumor growth was inhibited significantly by oxaliplatin combined with ?-elemene, as compared with oxaliplatin alone. Notably, CTR1 protein expression in xenograft HCC was upregulated in mice who received ?-elemene treatment. Taken together, our findings show that ?-elemene can block the reduction of CTR1 resulting from oxaliplatin treatment, and therefore has a synergistic anti-HCC effect with oxaliplatin by enhancing cellular uptake of oxaliplatin. The synergistic effects of ?-elemene and oxaliplatin deserve further evaluation in clinical settings.
Project description:?-elemene is a noncytotoxic Class II antitumor drug extracted from the traditional Chinese medicine Curcuma wenyujin Y. H. Chen et C. Ling. ?-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 ?-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 ?-elemene are also summarized. On the other hand, a number of highly active anticancer ?-elemene derivatives have been obtained through modification of the structure of ?-elemene. This review focuses on the two drug delivery systems and derivatives of ?-elemene for cancer therapy.
Project description:?-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 ?-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 ?-elemene remarkably decreased viability of the cells. The cells that were treated with ?-elemene had a much lower speed of moving toward the gap in comparison to untreated cell lines. ?-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 ?-elemene than in control groups (p <0.05). Moreover, tumor progression in subcutaneous xenograft nude mice was delayed with the injection of ?-elemene. Altogether, our findings suggest that ?-elemene inhibits proliferation, migration and tumorigenicity of human glioblastoma cells through suppressing RNF135.
Project description: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 ?-elemene, a compound derived from natural plants, exhibited a remarkable proliferation repression on ESFT cells, which was weakened by a caspase inhibitor Z-VAD. ?-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 ?-elemene on IR signaling pathway. ?-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 ?-elemene specifically in tumor cells other than normal hepatocytes. In addition, ?-elemene inhibited the growth of ESFT xenografts in vivo, and the phosphorylation of IR and S6 ribosomal protein was significantly repressed in the ?-elemene-treated xenografts. These data suggest that ?-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 ?-elemene alone or in combination with IGF1R blockades in ESFTs and IR signaling hyperactivated tumors.
Project description:?-elemene, a compound derived from Rhizoma zedoariae, is a promising new plant-derived drug with broad-spectrum anticancer activity. However, the underlying mechanism by which this agent inhibits human lung cancer cell growth has not been well elucidated. In this study, we showed that ?-elemene inhibits human non-small cell lung carcinoma (NSCLC) cell growth, and increased phosphorylation of ERK1/2, Akt and AMPK?. Moreover, ?-elemene inhibited expression of DNA methyltransferase 1 (DNMT1), which was not observed in the presence of the specific inhibitors of ERK (PD98059) or AMPK (compound C). Overexpression of DNMT1 reversed the effect of ?-elemene on cell growth. Interestingly, metformin not only reversed the effect of ?-elemene on phosphorylation of Akt but also strengthened the ?-elemene-reduced DNMT1. In addition, ?-elemene suppressed Sp1 protein expression, which was eliminated by either ERK1/2 or AMPK inhibitor. Conversely, overexpression of Sp1 antagonized the effect of ?-elemene on DNMT1 protein expression and cell growth. Taken together, our results show that ?-elemene inhibits NSCLC cell growth via ERK1/2- and AMPK?-mediated inhibition of transcription factor Sp1, followed by reduction in DNMT1 protein expression. Metformin augments the effect of ?-elemene by blockade of Akt signalling and additively inhibition of DNMT1 protein expression. The reciprocal ERK1/2 and AMPK? signalling pathways contribute to the overall responses of ?-elemene. This study reveals a potential novel mechanism by which ?-elemene inhibits growth of NSCLC cells.
Project description:F-box and WD repeat domain-containing 7 (FBW7) is a SCF-type E3 ubiquitin ligase targeting a multitude of oncoproteins for degradation. Acting as one of the most important tumor suppressors, it is frequently inactivated in various tumors. In this study we aimed to evaluate the relationship of FBW7 with glioma pathology and prognosis, and examine its effect in glioma malignancies and temozolomide (TMZ)-based therapy. Clinical tissues and TCGA database analysis revealed that FBW7 expression was correlated inversely with glioma histology and positively with patient survival time. Lentivirus transfection-induced FBW7 overexpression significantly suppressed proliferation, invasion and migration of U251 and U373 cells, whereas knockdown of FBW7 by targeted shRNA promoted proliferation, invasion and migration of glioma cells. Most importantly, the expression level of FBW7 was found to affect the 50% inhibitory concentration (IC50) of U251 and the TMZ-resistant variant. Combining TMZ with FBW7 overexpression notably increased the cytotoxicity compared to TMZ treatment alone, which was conversely attenuated by FBW7 knockdown. Moreover, flow cytometry (FC) analysis showed overexpression of FBW7, TMZ or the combination-increased proportion of G2/M arrest and the apoptotic rate, whereas FBW7 inhibition reduced G2/M arrest and apoptosis in U251 cells. Finally, mechanistic study found that FBW7 overexpression downregulated Aurora B, Mcl1 and Notch1 levels in a time-dependent pattern and this expressional suppression was independent of TMZ. These findings collectively demonstrate the critical role of FBW7 as a prognostic factor and a potential target to overcome chemoresistance of glioblastoma.
Project description:<b>Background and Purpose</b>: RAS mutations limit the effectiveness of anti-epidermal growth factor receptor (EGFR) monoclonal antibodies in combination with chemotherapy for metastatic colorectal cancer (mCRC) patients. Therefore, new cell death forms have focused on identifying indirect targets to inhibit Ras-induced oncogenesis. Recently, emerging evidence has shown the potential of triggering ferroptosis for cancer therapy, particularly for eradicating aggressive malignancies that are resistant to traditional therapies. <b>Methods</b>: KRAS mutant CRC cell HCT116 and Lovo were treated with cetuximab and ?-elemene, a bioactive compound isolated from Chinese herb <i>Curcumae Rhizoma</i>. Ferroptosis and epithelial-mesenchymal transformation (EMT) were detected <i>in vitro</i> and <i>in vivo</i>. Orthotopic CRC animal model were established and the tumor growth was monitored by IVIS bioluminescence imaging. Tumor tissues were collected to determine ferroptosis effect and the expression of EMT markers after the treatment. <b>Results</b>: CCK-8 assay showed that synergetic effect was obtained when 125 µg/ml ?-elemene was combined with 25 µg/ml cetuximab in KRAS mutant CRC cells. AV/PI staining suggested a non-apoptotic mode of cell death after the treatment with ?-elemene and cetuximab. <i>In vitro</i>, ?-elemene in combination with cetuximab was shown to induce iron-dependent reactive oxygen species (ROS) accumulation, glutathione (GSH) depletion, lipid peroxidation, upregulation of HO-1 and transferrin, and downregulation of negative regulatory proteins for ferroptosis (GPX4, SLC7A11, FTH1, glutaminase, and SLC40A1) in KRAS mutant CRC cells. Meanwhile, combinative treatment of ?-elemene and cetuximab inhibited cell migration and decreased the expression of mesenchymal markers (Vimentin, N-cadherin, Slug, Snail and MMP-9), but promoted the expression of epithelial marker E-cadherin. Moreover, ferroptosis inhibitors but not other cell death suppressors abrogated the effect of ?-elemene in combination with cetuximab on KRAS mutant CRC cells. <i>In vivo</i>, co-treatment with ?-elemene and cetuximab inhibited KRAS mutant tumor growth and lymph nodes metastases. <b>Conclusions</b>: Our data for the first time suggest that the natural product ?-elemene is a new ferroptosis inducer and combinative treatment of ?-elemene and cetuximab is sensitive to KRAS mutant CRC cells by inducing ferroptosis and inhibiting EMT, which will hopefully provide a prospective strategy for CRC patients with RAS mutations.
Project description:Herein, we report the first access of ?-elemene derivatives through the SeO2-mediated oxidation reaction. Several new compounds were isolated through such a one-step reaction, and their structures were elucidated using various 2D-NMR techniques. This method provides easy access to multiple oxidative ?-elemene derivatives in one single step and represents the first modifications on cyclohexyl ring of ?-elemene. It is expected to open up the opportunity for future derivatization on cyclohexyl ring of ?-elemene. The new compounds obtained above showed better anti-proliferation activities than ?-elemene itself on several cancer cell lines. Among them, compound 17 shows the best activity in antiproliferation assays of A549 and U-87MG cell lines.
Project description:The present study aimed to investigate the significant role of ?-elemene in mouse models of oxygen-induced retinopathy (OIR). C57BL/6J neonatal mice were used to establish OIR models. They were divided into four groups: Normoxia, OIR, OIR control and OIR?treated. Mice in the OIR group were exposed to 75±5% oxygen for 5 days and returned to a normal oxygen environment on postnatal day 12 (P12). The OIR treated group was intravitreally injected with 1 µl ??elemene on P12 and subsequently returned to a normal oxygen environment for 5 days (P12?P17). Retinas were obtained on P17. Retinal neovascularization (RNV) was detected using adenosine diphosphatase staining and analyzed by counting the nuclei of neovascular endothelial cells. Vascular endothelial growth factor (VEGF) expression was determined by reverse transcription?quantitative polymerase chain reaction, immunohistochemistry and western blot analysis. MicroRNA (miRNA/miR) microarrays were used to screen out differentially expressed miRNAs between the OIR and ??elemene?treated groups. Binding the 3'?untranslated region (UTR) of VEGF and miR?27a was confirmed using luciferase assays. It was found that high oxygen concentrations accelerated RNV and increased the number of preretinal neovascular cells; ??elemene treatment reduced these effects. VEGF mRNA and protein expression was higher in the OIR and OIR control groups, compared with the normoxia and OIR?treated groups. Further, it was shown that miR?22, miR?181a?1, miR?335?5p, miR?669n, miR?190b, miR?27a and miR?93 were upregulated in the OIR?treated group, and downregulated in the OIR group. The prediction websites TargetScan and miRanda revealed that VEGF contained a potential miR?27a binding site in its 3'?untranslated region (UTR). Luciferase assays demonstrated that miR?27a directly bound to the 3'?UTR of VEGF. In vitro experiments demonstrated that miR?27a inhibited VEGF expression. In addition, ??elemene treatment upregulate miR?27a expression in vivo and in vitro. When miR?27a expression was depleted by miR?27a inhibitor, the protective effect of ??elemene on RNV was eliminated. The present study demonstrated that ??elemene reduced RNV in mouse OIR models via miR?27a upregulation, leading to reduced VEGF expression. This finding may contribute to the development of novel therapeutic strategies for human retinopathy.
Project description:Glioblastoma is the most aggressive brain tumor in adults with a median survival below 12 months in population-based studies. The main reason for tumor recurrence and progression is constitutive or acquired resistance to the standard of care of surgical resection followed by radiotherapy with concomitant and adjuvant temozolomide (TMZ/RT?TMZ). Here, we investigated the role of microRNA (miRNA) alterations as mediators of alkylator resistance in glioblastoma cells. Using microarray-based miRNA expression profiling of parental and TMZ-resistant cultures of three human glioma cell lines, we identified a set of differentially expressed miRNA candidates. From these, we selected miR-138 for further functional analyses as this miRNA was not only upregulated in TMZ-resistant versus parental cells, but also showed increased expression in vivo in recurrent glioblastoma tissue samples after TMZ/RT?TMZ treatment. Transient transfection of miR-138 mimics in glioma cells with low basal miR-138 expression increased glioma cell proliferation. Moreover, miR-138 overexpression increased TMZ resistance in long-term glioblastoma cell lines and glioma initiating cell cultures. The apoptosis regulator BIM was identified as a direct target of miR-138, and its silencing mediated the induced TMZ resistance phenotype. Altered sensitivity to apoptosis played only a minor role in this resistance mechanism. Instead, we identified the induction of autophagy to be regulated downstream of the miR-138/BIM axis and to promote cell survival following TMZ exposure. Our data thus define miR-138 as a glioblastoma cell survival-promoting miRNA associated with resistance to TMZ therapy in vitro and with tumor progression in vivo.