Oleanolic acid suppresses migration and invasion of malignant glioma cells by inactivating MAPK/ERK signaling pathway

Self-Assembled nanoparticles of natural bioactive molecules enhance the delivery and efficacy of paclitaxel in glioblastoma

BACKGROUND

Glioblastoma (GBM) is the most common primary malignant tumor in the central nervous system. Paclitaxel (PTX) is a well-established and highly effective anti-cancer drug for peripheral solid tumors. However, the application of PTX in GBM is hindered by several limitations, including poor water solubility, restricted entry across the blood-brain barrier (BBB), and enhanced excretion by efflux transporters. P-glycoprotein (P-gp) is a crucial efflux transporter that is abundantly present in cerebral vascular endothelial cells and GBM cells. It plays a significant role in the exocytosis of PTX within tumor tissues.

METHODS

Recently, we have developed a novel technique for creating self-assembled nanoparticles utilizing a range of natural bioactive molecules. These nanoparticles can encapsulate insoluble drugs and effectively cross the BBB. In additional, we revealed that certain nanoparticles have the potential to act as P-gp inhibitors, thereby reducing the excretion of PTX. In this study, we conducted a screening of bioactive molecular nanoparticles to identify those that effectively inhibit the function of P-gp transporters.

RESULTS

Among the candidates, we identified ursolic acid nanoparticles (UA NPs) as the P-gp inhibitors. Furthermore, we prepared co-assembled UA NPs embedded with paclitaxel, referred to as UA-PTX NPs. Our results demonstrate that UA-PTX NPs can enhance the blood concentration of PTX, facilitate its entry into the BBB, and inhibit the function of P-gp, resulting in a decrease in the excretion of PTX. This discovery effectively addressed the above three issues associated with the use of PTX in glioma treatment.

CONCLUSIONS

UA-PTX NPs demonstrate strong anti-tumor effects and show great potential for treating GBM.

Oleanolic acid increases the anticancer potency of doxorubicin in pancreatic cancer cells

Combination therapy is a novel cancer therapy approach that combines two or more chemotherapy drugs. This treatment modality enhances the efficacy of chemotherapy by targeting key pathways in an additive or synergistic manner. Therefore, we investigated the efficacy of combination therapy by widely used chemotherapy drug doxorubicin (DOX) and oleanolic acid (OA) to induction of apoptosis for pancreatic cancer (PC) therapy. The effects of DOX, OA, and their combination (DOX-OA) were investigated on proliferation and viability of PC cell line (PANC-1) by MTT assay. Moreover, migration and invasion of the cancer cells were evaluated by trans-well migration assay and wound healing assay. Flow cytometry and DAPI (4',6-diamidino-2-phenylindole) staining were employed to investigate apoptosis quantification and qualification of the treated cancer cells. Finally, mRNA expression of apoptosis-related genes was assessed by quantitative real-time polymerase chain reaction. Our results demonstrated that the proliferation and metastasis potential of PC cells significantly decreased after treatment by DOX, OA, and DOX-OA. Moreover, we observed an increase in apoptosis percentage in the treated cancer cells. The apoptosis-related gene expression was modified to increase the apoptosis rate in all of the treatment groups. However, the anticancer potency of DOX-OA combination was significantly more than that of DOX and OA treatments alone. Our study suggested that DOX-OA combination exerts more profound anticancer effects against PC cell lines than DOX or OA monotherapy. This approach may increase the efficiency of chemotherapy and reduce unintended side effects by lowering the prescribed dose of DOX.

A computational and laboratory approach for the investigation of interactions of peptide conjugated natural terpenes with EpHA2 receptor

CONTEXT

Ephrin type A receptor 2 (EphA2) is a well-known drug target for cancer treatment due to its overexpression in numerous types of cancers. Thus, it is crucial to determine the binding interactions of this receptor with both the ligand-binding domain (LBD) and the kinase-binding domain (KBD) through a targeted approach in order to modulate its activity. In this work, natural terpenes with inherent anticancer properties were conjugated with short peptides YSAYP and SWLAY that are known to bind to the LBD of EphA2 receptor. We examined the binding interactions of six terpenes (maslinic acid, levopimaric acid, quinopimaric acid, oleanolic, polyalthic, and hydroxybetulinic acid) conjugated to the above peptides with the ligand-binding domain (LBD) of EphA2 receptor computationally. Additionally, following the "target-hopping approach," we also examined the interactions of the conjugates with the KBD. Our results indicated that most of the conjugates showed higher binding interactions with the EphA2 kinase domain compared to LBD. Furthermore, the binding affinities of the terpenes increased upon conjugating the peptides with the terpenes. In order to further investigate the specificity toward EphA2 kinase domain, we also examined the binding interactions of the terpenes conjugated to VPWXE (x = norleucine), as VPWXE has been shown to bind to other RTKs. Our results indicated that the terpenes conjugated to SWLAY in particular showed high efficacy toward binding to the KBD. We also designed conjugates where in the peptide portion and the terpenes were separated by a butyl (C4) group linker to examine if the binding interactions could be enhanced. Docking studies showed that the conjugates with linkers had enhanced binding with the LBD compared to those without linkers, though binding remained slightly higher without linkers toward the KBD. As a proof of concept, maslinate and oleanolate conjugates of each of the peptides were then tested with F98 tumor cells which are known to overexpress EphA2 receptor. Results indicated that the oleanolate-amido-SWLAY conjugates were efficacious in reducing the cell proliferation of the tumor cells and may be potentially developed and further studied for targeting tumor cells overexpressing the EphA2 receptor. To test if these conjugates could bind to the receptor and potentially function as kinase inhibitors, we conducted SPR analysis and ADP-Glo assay. Our results indicated that OA conjugate with SWLAY showed the highest inhibition.

METHODS

Docking studies were carried out using AutoDock Vina, v.1.2.0; Molecular Dynamics and MMGBSA calculations were carried out through Schrodinger Software DESMOND.

Mechanism of epithelial-mesenchymal transition in cancer and its regulation by natural compounds

Epithelial-mesenchymal transition (EMT) is a complex process with a primordial role in cellular transformation whereby an epithelial cell transforms and acquires a mesenchymal phenotype. This transformation plays a pivotal role in tumor progression and self-renewal, and exacerbates resistance to apoptosis and chemotherapy. EMT can be initiated and promoted by deregulated oncogenic signaling pathways, hypoxia, and cells in the tumor microenvironment, resulting in a loss-of-epithelial cell polarity, cell-cell adhesion, and enhanced invasive/migratory properties. Numerous transcriptional regulators, such as Snail, Slug, Twist, and ZEB1/ZEB2 induce EMT through the downregulation of epithelial markers and gain-of-expression of the mesenchymal markers. Additionally, signaling cascades such as Wnt/β-catenin, Notch, Sonic hedgehog, nuclear factor kappa B, receptor tyrosine kinases, PI3K/AKT/mTOR, Hippo, and transforming growth factor-β pathways regulate EMT whereas they are often deregulated in cancers leading to aberrant EMT. Furthermore, noncoding RNAs, tumor-derived exosomes, and epigenetic alterations are also involved in the modulation of EMT. Therefore, the regulation of EMT is a vital strategy to control the aggressive metastatic characteristics of tumor cells. Despite the vast amount of preclinical data on EMT in cancer progression, there is a lack of clinical translation at the therapeutic level. In this review, we have discussed thoroughly the role of the aforementioned transcription factors, noncoding RNAs (microRNAs, long noncoding RNA, circular RNA), signaling pathways, epigenetic modifications, and tumor-derived exosomes in the regulation of EMT in cancers. We have also emphasized the contribution of EMT to drug resistance and possible therapeutic interventions using plant-derived natural products, their semi-synthetic derivatives, and nano-formulations that are described as promising EMT blockers.

Lipid Alterations in Glioma: A Systematic Review

Gliomas are highly lethal tumours characterised by heterogeneous molecular features, producing various metabolic phenotypes leading to therapeutic resistance. Lipid metabolism reprogramming is predominant and has contributed to the metabolic plasticity in glioma. This systematic review aims to discover lipids alteration and their biological roles in glioma and the identification of potential lipids biomarker. This systematic review was conducted using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Extensive research articles search for the last 10 years, from 2011 to 2021, were conducted using four electronic databases, including PubMed, Web of Science, CINAHL and ScienceDirect. A total of 158 research articles were included in this study. All studies reported significant lipid alteration between glioma and control groups, impacting glioma cell growth, proliferation, drug resistance, patients' survival and metastasis. Different lipids demonstrated different biological roles, either beneficial or detrimental effects on glioma. Notably, prostaglandin (PGE2), triacylglycerol (TG), phosphatidylcholine (PC), and sphingosine-1-phosphate play significant roles in glioma development. Conversely, the most prominent anti-carcinogenic lipids include docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and vitamin D3 have been reported to have detrimental effects on glioma cells. Furthermore, high lipid signals were detected at 0.9 and 1.3 ppm in high-grade glioma relative to low-grade glioma. This evidence shows that lipid metabolisms were significantly dysregulated in glioma. Concurrent with this knowledge, the discovery of specific lipid classes altered in glioma will accelerate the development of potential lipid biomarkers and enhance future glioma therapeutics.

Correlation of Glucose Metabolism with Cancer and Intervention with Traditional Chinese Medicine

Cancer is a complex disease with several distinct characteristics, referred to as “cancer markers” one of which is metabolic reprogramming, which is a common feature that drives cancer progression. Over the last ten years, researchers have focused on the reprogramming of glucose metabolism in cancer. In cancer, the oxidative phosphorylation metabolic pathway is converted into the glycolytic pathway in order to meet the growth requirements of cancer cells, thereby creating a microenvironment that promotes cancer progression. The precise mechanism of glucose metabolism in cancer cells is still unknown, but it is thought to involve the aberrant levels of metabolic enzymes, the influence of the tumor microenvironment (TME), and the activation of tumor-promoting signaling pathways. It is suggested that glucose metabolism is strongly linked to cancer progression because it provides energy to cancer cells and interferes with antitumor drug pharmacodynamics. Therefore, it is critical to unravel the mechanism of glucose metabolism in tumors in order to gain a better understanding of tumorigenesis and to lay the groundwork for future research into the identification of novel diagnostic markers and therapeutic targets for cancer treatment. Traditional Chinese Medicine (TCM) has the characteristics of multiple targets, multiple components, and less toxic side effects and has unique advantages in tumor treatment. In recent years, researchers have found that a variety of Chinese medicine monomers and compound recipes play an antitumor role by interfering with the reprogramming of tumor metabolism. The underlying mechanisms of metabolism reprogramming of tumor cells and the role of TCM in regulating glucose metabolism are reviewed in this study, so as to provide a new idea for antitumor research in Chinese medicine.

Exploring the underlying mechanism of oleanolic acid treating glioma by transcriptome and molecular docking

OBJECTIVE

Oleanolic acid is a promising drug for treating gliomas, but its underlying mechanism is unclear. This study aimed to determine the potential effect of oleanolic acid on glioma and its mechanism.

METHODS

Firstly, the effects of oleanolic acid on the proliferation, invasion, and apoptosis of glioma U251 cells were detected by in vitro experiments such as MTT assay, cell cloning, and flow cytometry. The transcriptome data of U251 cells treated with oleanolic acid and untreated were sequenced by mRNA, and then the differentially expressed genes were analyzed by gene ontology (GO), genomic encyclopedia (KEGG) pathway enrichment analysis, and protein interaction topology analysis. The underlying mechanism of oleanolic acid was predicted, and the related protein interaction network was constructed. Finally, Western blotting and molecular docking techniques verified the mRNA sequencing results.

RESULTS

Oleanolic acid could effectively inhibit the proliferation, colony formation, and invasion of U251 cells and induce apoptosis. A total of 446 differentially expressed genes were detected by mRNA sequencing, of which 96 genes were up-regulated and 350 down-regulated. Oleanolic acid induces the TNF signal pathway and NOD-like receptor signal pathway at the intracellular level. In addition, OAS2, OASL, IFIT3, RSAD2, and IRF1 may be the core targets of oleanolic acid in treating glioma.

CONCLUSION

Transcriptome combined with molecular docking technique is used to predict the possible mechanism of oleanolic acid in the treatment of glioma, which provides new ideas and insights for developing and researching antitumor drugs.

Matrix Hyaluronic Acid and Hypoxia Influence a CD133+ Subset of Patient-Derived Glioblastoma Cells

Glioblastoma (GBM) displays diffusive invasion throughout the brain microenvironment, which is partially responsible for its short median survival rate (<15 months). Stem-like subpopulations (GBM stem-like cells, GSCs) are believed to play a central role in therapeutic resistance and poor patient prognosis. Given the extensive tissue remodeling and processes such as vessel co-option and regression that occur in the tumor microenvironment, it is essential to understand the role of metabolic constraint such as hypoxia on GBM cell populations. This work describes the use of a multidimensional gelatin hydrogel to culture patient-derived GBM cells, to evaluate the influence of hypoxia and the inclusion brain-mimetic hyaluronic acid on the relative activity of GSCs versus overall GBM cells. Notably, CD133+ GBM cell fraction is crucial for robust formation of tumor spheroids in multidimensional cultures. In addition, while the relative size of the CD133+ GBM subpopulation increased in response to both hypoxia and matrix-bound hyaluronan, we did not observe cell subtype-specific changes in invasion signaling pathway activation. Taken together, this study highlights the potential of biomimetic culture systems for resolving changes in the population dynamics and behavior of subsets of GBM specimens for the future development of precision medicine applications. Impact Statement This study describes a gelatin hydrogel platform to investigate the role of extracellular hyaluronic acid and hypoxia on the behavior of a CD133+ subset of cells within patient-derived glioblastoma (GBM) specimens. We report that the relative expansion of the CD133+ GBM stem cell-like population is strongly responsive to extracellular cues, highlighting the significance of biomimetic hydrogel models of the tumor microenvironment to investigate invasion and therapeutic response.

Mesenchymal stem cell-derived extracellular vesicles prevent glioma by blocking M2 polarization of macrophages through a miR-744-5p/TGFB1-dependent mechanism

AIM

Our current study is conducted with intention to explore the regulatory mechanism of mesenchymal stem cell (MSC)-derived extracellular vesicle (EV)-miR-744-5p in glioma.

METHODS

Expression patterns of TGFB1, TGFBR1, and miR-744-5p were determined. EVs were isolated from human MSCs, which were characterized. Then, macrophages were co-cultured with MSCs with ectopic miR-744-5p expression to explore its role in cell proliferation, invasion, and migration capabilities. A nude mouse model of glioma xenograft was developed to observe the tumorigenesis and metastasis ability of glioma in vivo.

RESULTS

TGFB1 and TGFBR1 were upregulated in glioma. TGFB1 promoted M2 polarization of macrophages through theMAPK signaling, thereby promoting the progression of glioma. MSC-EVs suppressed TGFB1 expression in macrophages and inhibited M2 polarization of macrophages. MSC-EVs-miR-744-5p/TGFB1/MAPK axis inhibited M2 polarization of macrophages and reduced the malignant phenotypes of glioma cells. In vivo experiments verified that MSC-EVs-miR-744-5p inhibited the polarization of macrophage M2 and prevented glioma progression.

CONCLUSION

Taken together, MSC-EVs-miR-744-5p may suppress the MAPK signaling activity by downregulating TGFB1, and then inhibit polarization of macrophages M2, thereby preventing the progression of glioma. Graphical Headlights 1. TGFB1 promotes the M2 polarization of macrophages via the MAPK signaling. 2. miR-744-5p carried by MSC-EVs targets and inhibits TGFB1. 3. MSC-EV-miR-744-5p inhibits M2 polarization of macrophages to prevent glioma progression. 4. miR-744-5p loaded by MSC-EVs may be a preventive strategy against glioma.

Knockdown of ER-α36 expression inhibits glioma proliferation, invasion and epithelial-to-mesenchymal transition

Estrogen receptor-α36 (ER-α36), a subtype of the estrogen receptor, is reported to play roles in tumorigenesis and tamoxifen resistance in several tumors, especially breast cancer. However, the role of ER-α36 in glioma proliferation and invasion remains unknown. Here, we explored the function of ER-α36 in glioma cells, using U87 and U251 cell lines. We found that ER-α36 was upregulated in glioma tissues compared to adjacent nontumor tissues. In U87 and U251 glioma cell lines, inhibition of ER-α36 expression by shRNA suppressed cell proliferation and invasion. In addition, the expression of an epithelial marker, ZO-1, was upregulated while that of one mesenchymal marker, N-cadherin, was downregulated with ER-α36 knockdown. We also found that inhibition of ER-α36 inactivated both PI3K/AKT and MEK/ERK signals. Taken together, these data indicated that overexpression of ER-α36 is associated with glioma proliferation and progression but that inhibition of ER-α36 leads to suppressed invasion and the epithelial-to-mesenchymal transition via PI3K/AKT and MEK/ERK pathway inactivation in glioma cells.

Drug Evaluation Based on a Multi-Channel Cell Chip with a Horizontal Co-Culture

We developed a multi-channel cell chip containing a three-dimensional (3D) scaffold for horizontal co-culture and drug toxicity screening in multi-organ culture (human glioblastoma, cervical cancer, normal liver cells, and normal lung cells). The polydimethylsiloxane (PDMS) multi-channel cell chip (PMCCC) was based on fused deposition modeling (FDM) technology. The architecture of the PMCCC was an open-type cell chip and did not require a pump or syringe. We investigated cell proliferation and cytotoxicity by conducting 3-(4,5-dimethylthiazol-2-yl)-2,5-dphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays and analysis of oleanolic acid (OA)-treated multi-channel cell chips. The results of the MTT and LDH assays showed that OA treatment in the multi-channel cell chip of four cell lines enhanced chemoresistance of cells compared with that in the 2D culture. Furthermore, we demonstrated the feasibility of the application of our multi-channel cell chip in various analysis methods through Annexin V-fluorescein isothiocyanate/propidium iodide staining, which is not used for conventional cell chips. Taken together, the results demonstrated that the PMCCC may be used as a new 3D platform because it enables simultaneous drug screening in multiple cells by single point injection and allows analysis of various biological processes.

Eriodictyol inhibits glioblastoma migration and invasion by reversing EMT via downregulation of the P38 MAPK/GSK-3β/ZEB1 pathway

Eriodictyol (ERD) is a natural flavonoid that exists in many vegetables and fruits, especially citrus fruits. It has been proven to have many pharmacological effects, such as antioxidative, anti-inflammatory and neuroprotective effects. Our previous study showed that eriodictyol could inhibit the proliferation and induce the apoptosis of glioblastoma cells by downregulating the PI3K/Akt/NF-κB pathway and restraining its migration and invasion. However, the mechanism by which eriodictyol prevents glioblastoma metastasis is still unknown. Epithelial-mesenchymal transition (EMT) is a key process for many cancer metastases; it also confers locomotivity to tumor cells, including glioblastoma. In this study, we found that eriodictyol can suppress the migration and invasion of glioblastoma A172 and U87 MG cell lines by suppressing the EMT markers - N-cadherin and E-cadherin through Wound healing and Transwell assays, Western blot, RT-qPCR, immunofluorescence and immunohistochemistry. Further research revealed that the mechanism could be connected with downregulation of the P38 MAPK/GSK-3β/ZEB1 signaling pathway. These findings can provide a new idea for the treatment of glioblastoma.

Identification of 2-Fluoropalmitic Acid as a Potential Therapeutic Agent Against Glioblastoma

BACKGROUND

Glioblastomas (GBMs) are aggressive malignant brain tumors. Although chemotherapy with temozolomide (TMZ) can extend patient survival, most patients eventually demonstrate resistance. Therefore, novel therapeutic agents that overcome TMZ chemoresistance are required to improve patient outcomes.

PURPOSE

Drug screening is an efficient method to find new therapeutic agents from existing drugs. In this study, we explored a novel anti-glioma agent by drug screening and analyzed its function with respect to GBM treatment for future clinical applications.

METHODS

Drug libraries containing 1,301 diverse chemical compounds were screened against two glioma stem cell (GSC) lines for drug candidate selection. The effect of selected agents on GSCs and glioma was estimated through viability, proliferation, sphere formation, and invasion assays. Combination therapy was performed to assess its ability to enhance TMZ cytotoxicity against GBM. To clarify the mechanism of action, we performed methylation-specific polymerase chain reaction, gelatin zymography, and western blot analysis.

RESULTS

The acyl-CoA synthetase inhibitor 2-fluoropalmitic acid (2-FPA) was selected as a candidate anti-glioma agent. 2-FPA suppressed the viability and stem-like phenotype of GSCs. It also inhibited proliferation and invasion of glioma cell lines. Combination therapy of 2-FPA with TMZ synergistically enhanced the efficacy of TMZ. 2-FPA suppressed the expression of phosphor-ERK, CD133, and SOX-2; reduced MMP-2 activity; and increased methylation of the MGMT promoter.

CONCLUSION

2-FPA was identified as a potential therapeutic agent against GBM. To extend these findings, physiological studies are required to examine the efficacy of 2-FPA against GBM in vivo.

Ursolic Acid Inhibits Collective Cell Migration and Promotes JNK-Dependent Lysosomal Associated Cell Death in Glioblastoma Multiforme Cells

Ursolic acid (UA) is a bioactive compound which has demonstrated therapeutic efficacy in a variety of cancer cell lines. UA activates various signalling pathways in Glioblastoma multiforme (GBM) and offers a promising starting point in drug discovery; however, understanding the relationship between cell death and migration has yet to be elucidated. UA induces a dose dependent cytotoxic response demonstrated by flow cytometry and biochemical cytotoxicity assays. Inhibitor and fluorescent probe studies demonstrate that UA induces a caspase independent, JNK dependent, mechanism of cell death. Migration studies established that UA inhibits GBM collective cell migration in a time dependent manner that is independent of the JNK signalling pathway. Cytotoxicity induced by UA results in the formation of acidic vesicle organelles (AVOs), speculating the activation of autophagy. However, inhibitor and spectrophotometric analysis demonstrated that autophagy was not responsible for the formation of the AVOs. Confocal microscopy and isosurface visualisation determined co-localisation of lysosomes with the previously identified AVOs, thus providing evidence that lysosomes are likely to be playing a role in UA induced cell death. Collectively, our data identify that UA rapidly induces a lysosomal associated mechanism of cell death in addition to UA acting as an inhibitor of GBM collective cell migration.

The Role and Therapeutic Targeting of JAK/STAT Signaling in Glioblastoma

Glioblastoma remains one of the deadliest and treatment-refractory human malignancies in large part due to its diffusely infiltrative nature, molecular heterogeneity, and capacity for immune escape. The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway contributes substantively to a wide variety of protumorigenic functions, including proliferation, anti-apoptosis, angiogenesis, stem cell maintenance, and immune suppression. We review the current state of knowledge regarding the biological role of JAK/STAT signaling in glioblastoma, therapeutic strategies, and future directions for the field.

Microarray analysis of aberrant microRNA expression patterns in spinal cord gliomas of different grades

MicroRNAs (miRNAs) are involved in the development of several types of tumor; however, their role in spinal gliomas remains unknown. The present study aimed to identify potentially novel spinal cord gliomas (SCG)-associated miRNAs and to characterize their roles in the development and progression of SCG. miRNA expression levels in low-grade SCG (classed as stage I–II SCG based on the World Health Organization grading system), high-grade SCG (classed as stage IV SCG based on the World Health Organization grading system) and 5 control cases were measured using a miRNA expression microarray. Subsequently, blood samples from the spinal cord of patients with differing grades of SCG were screened for differentially expressed miRNAs (DEmiRNAs). Compared with the control group, 7 upregulated and 36 downregulated miRNAs were identified in the low-grade SCG group and a total of 70 upregulated and 20 downregulated miRNAs were identified in the high-grade SCG group (P≤0.05, fold change >2). Gene Ontology analysis revealed that the regulation of cellular metabolic processes, negative regulation of biological processes and axon guidance were primarily involved. Moreover, pathway analysis showed that the target genes of DEmiRNAs were enriched in tumor-related signaling pathways, such as the MAPK and Wnt signaling pathway. The results suggest that DEmiRNAs in peripheral blood may serve as novel target markers with high specificity and sensitivity for the diagnosis of SCG.

Double-Targeted Knockdown of miR-21 and CXCR4 Inhibits Malignant Glioma Progression by Suppression of the PI3K/AKT and Raf/MEK/ERK Pathways

Currently, miR-21 and CXCR4 are being extensively investigated as two key regulators in glioma malignancy. In this study, we investigated the combined effects of these two factors on glioma progression. Herein, the expression of miR-21 and CXCR4 was increased in tumor tissues and cell lines. Inhibition of miR-21, CXCR4, and miR-21 and CXCR4 together all reduced the migration, invasiveness, proliferation, and enhanced apoptosis in glioma cells, as well as reduced tumor volume and mass in xenograft model. The inhibition effect was strongest in double-targeted knockdown of miR-21 and CXCR4 group, whose downstream pathways involved in AKT axis and ERK axis activation. In conclusion, our findings reported that double-targeted knockdown of miR-21 and CXCR4 could more effectively inhibit the proliferation, migration, invasion, and growth of transplanted tumor and promote cell apoptosis, which were involved in the PI3K/AKT and Raf/MEK/ERK signaling pathways.

Nanocrystallized Oleanolic Acid Better Inhibits Proliferation, Migration and Invasion in Intracranial Glioma via Caspase-3 Pathway

Glioma associates with high malignancy and poor prognosis for traditional treatment. Oleanolic acid (OA) has been confirmed to have an inhibitory effect on different kinds of tumors, while accompanying with low efficiency because of its large molecular mass and low solubility. Nanoliposome is an appropriate drug delivery system that can compensate for the limitations of traditional insoluble drugs, involving improvement of their solubility, stability and lipophilicity. In the present study, we comprised of OA covered with nanoliposomes, named OA^nano, to observe antitumor effects on U87 glioma cells. The results showed that OA^nano raised the solubility and oil-water partition coefficient. OA^nano suppressed proliferation of U87 glioma cells, and also had an anticancer effect on U87 glioma cells, which was found to be higher than that of OA. Moreover, treatment with OA^nano induced apoptosis and degraded migration ability by caspase-3 pathway. In conclusion, our results demonstrated that OA covered with nanoliposomes led to enhanced anticancer effects by suppressing proliferation, migration and invasion abilities. The findings may provide a reliable reference for development of new anti-cancer drugs.

CircNFIX promotes progression of glioma through regulating miR-378e/RPN2 axis

Background

Circular RNA nuclear factor I X (circNFIX) has been reported to play an important role in glioma progression. However, the mechanism by which circNFIX participates in glioma progression remains poorly understood.

Methods

GERIA online were used to analyze the abnormally expressed genes in glioma tissues. The expression levels of circNFIX, microRNA (miR)-378e and Ribophorin-II (RPN2) were measured by quantitative real-time polymerase chain reaction or western blot. Cell cycle distribution, apoptosis, glycolysis, migration and invasion were determined by flow cytometry, special kit and trans-well assays, respectively. The target association between miR-378e and circNFIX or RPN2 was confirmed by luciferase reporter assay, RNA immunoprecipitation and pull-down. Xenograft model was established to investigate the role of circNFIX in vivo.

Results

The expression of circNFIX was enhanced in glioma tissues and cells compared with matched controls and high expression of circNFIX indicated poor outcomes of patients. Knockdown of circNFIX led to arrest of cell cycle, inhibition of glycolysis, migration and invasion and promotion of apoptosis in glioma cells. circNFIX was a sponge of miR-378e. miR-378e overexpression suppressed cell cycle process, glycolysis, migration and invasion but promoted apoptosis. miR-378e silence abated the suppressive role of circNFIX knockdown in glioma progression. RPN2 as a target of miR-378e was positively regulated via circNFIX by competitively sponging miR-378e. Silencing circNFIX decreased glioma xenograft tumor growth by regulating miR-378e/RPN2 axis.

Conclusion

Knockdown of circNFIX inhibits progression of glioma in vitro and in vivo by increasing miR-378e and decreasing RPN2, providing a novel mechanism for understanding the pathogenesis of glioma.

Stoichioproteomics reveal oxygen usage bias, key proteins and pathways in glioma

Background

The five-year survival rate and therapeutic effect of malignant glioma is low. Identification of key/associated proteins and pathways in glioma is necessary for developing effective diagnosis and targeted therapy of glioma. In addition, Glioma involves hypoxia-specific microenvironment, whether hypoxia restriction influences the stoichioproteomic characteristics of expressed proteins is unknown.

Methods

In this study, we analyzed the most comprehensive immunohistochemical data from 12 human glioma samples and 4 normal cell types of cerebral cortex, identified differentially expressed proteins (DEPs), and researched the oxygen contents of DEPs, highly and lowly expressed proteins. Further we located key genes on human genome to determine their locations and enriched them for key functional pathways.

Results

Our results showed that although no difference was detected on whole proteome, the average oxygen content of highly expressed proteins is 6.65% higher than that of lowly expressed proteins in glioma. A total of 1480 differentially expressed proteins were identified in glioma, including 226 up regulated proteins and 1254 down regulated proteins. The average oxygen content of up regulated proteins is 2.56% higher than that of down regulated proteins in glioma. The localization of differentially expressed genes on human genome showed that most genes were on chromosome 1 and least on Y. The up regulated proteins were significantly enriched in pathways including cell cycle, pathways in cancer, oocyte meiosis, DNA replication etc. Functional dissection of the up regulated proteins with high oxygen contents showed that 51.28% of the proteins were involved in cell cycle and cyclins.

Conclusions

Element signature of oxygen limitation could not be detected in glioma, just as what happened in plants and microbes. Unsaved use of oxygen by the highly expressed proteins and DEPs were adapted to the fast division of glioma cells. This study can help to reveal the molecular mechanism of glioma, and provide a new approach for studies of cancer-related biomacromolecules. In addition, this study lays a foundation for application of stoichioproteomics in precision medicine.

Electronic supplementary material

The online version of this article (10.1186/s12920-019-0571-y) contains supplementary material, which is available to authorized users.

Stoichiogenomics reveal oxygen usage bias, key proteins and pathways associated with stomach cancer

Stomach cancer involves hypoxia-specific microenvironments. Stoichiogenomics explores environmental resource limitation on biological macromolecules in terms of element usages. However, the patterns of oxygen usage by proteins and the ways that proteins adapt to a cancer hypoxia microenvironment are still unknown. Here we compared the oxygen and carbon contents ([C]) between proteomes of stomach cancer (hypoxia) and two stomach glandular cells (normal). Key proteins, genome locations, pathways, and functional dissection associated with stomach cancer were also studied. An association of oxygen content ([O]) and protein expression level was revealed in stomach cancer and stomach glandular cells. For differentially expressed proteins (DEPs), oxygen contents in the up regulated proteins were3.2%higherthan that in the down regulated proteins in stomach cancer. A total of 1,062 DEPs were identified; interestingly none of these proteins were coded on Y chromosome. The up regulated proteins were significantly enriched in pathways including regulation of actin cytoskeleton, cardiac muscle contraction, pathway of progesterone-mediated oocyte maturation, etc. Functional dissection of the up regulated proteins with high oxygen contents showed that most of them were cytoskeleton, cytoskeleton associated proteins, cyclins and signaling proteins in cell cycle progression. Element signature of resource limitation could not be detected in stomach cancer for oxygen, just as what happened in plants and microbes. Unsaved use of oxygen by the highly expressed proteins was adapted to the rapid growth and fast division of the stomach cancer cells. In addition, oxygen usage bias, key proteins and pathways identified in this paper laid a foundation for application of stoichiogenomics in precision medicine.

Modulation of Epithelial to Mesenchymal Transition Signaling Pathways by Olea Europaea and Its Active Compounds

Epithelial-mesenchymal transition (EMT) is a significant dynamic process that causes changes in the phenotype of epithelial cells, changing them from their original phenotype to the mesenchymal cell phenotype. This event can be observed during wound healing process, fibrosis and cancer. EMT-related diseases are usually caused by inflammation that eventually leads to tissue remodeling in the damaged tissue. Prolonged inflammation causes long-term EMT activation that can lead to tissue fibrosis or cancer. Due to activation of EMT by its signaling pathway, therapeutic approaches that modulate that pathway should be explored. Olea europaea (OE) is well-known for its anti-inflammatory effects and abundant beneficial active compounds. These properties are presumed to modulate EMT events. This article reviews recent evidence of the effects of OE and its active compounds on EMT events and EMT-related diseases. Following evidence from the literature, it was shown that OE could modulate TGFβ/SMAD, AKT, ERK, and Wnt/β-catenin pathways in EMT due to a potent active compound that is present therein.

MiR-9 promotes synovial sarcoma cell migration and invasion by directly targeting CDH1

BACKGROUND

Invasion and metastasis of synovial sarcoma is the leading cause of death in patients. Epithelial mesenchymal transition (EMT) accelerates tumor cell invasion and metastasis. MiR-9 promotes tumor metastasis by inducing EMT. However, the role of miR-9 in synovial sarcoma is still not clear.

METHODS

Overexpression or knockdown of miR-9 in human synovial sarcoma (HSS) cell lines was carried out by miR-9 mimics or miR-9 inhibitors transfection. Cell proliferation, apoptosis, migration and invasion were detected using MTS and colony formation assays, flow cytometry, wound healing and transwell assays, respectively. Luciferase reporter assay was applied to study the interaction between miR-9 and CDH1. Nude mice xenograft model was established, and immunohistochemistry staining assessed Ki-67 level. The related mRNA and protein expression levels were evaluated by qRT-PCR and Western blotting.

RESULTS

The bioinformatics analyses and luciferase reporter assay showed that miR-9 can target CDH1 3'-UTR. Moreover, miR-9 could induce EMT of HSS cells via targeting CDH1. The negative regulation of miR-9 on CDH1 expression was also confirmed in a mouse xenograft model of synovial sarcoma. Furthermore, miR-9 was observed to induce HSS cell proliferation, migration and invasion and inhibit apoptosis. MAPK/ERK and Wnt/β-catenin signal pathways were activated by the miR-9 overexpression in HSS cells, and then further enhancing tumorigenesis of HSS, which was further confirmed in the mouse model.

CONCLUSION

MiR-9 induces EMT by targeting CDH1, and activates MAPK/ERK and Wnt/β-catenin signal pathways, thus promoting HSS tumorigenesis.

Epithelial-mesenchymal transition as a target for botanicals in cancer metastasis

BACKGROUND

The plant kingdom represents an unlimited source of phytotherapeutics with promising perspectives in the field of anticancer drug discovery.

PURPOSE

In this view, epithelial-mesenchymal transition (EMT) represents a novel and major target in anticancer therapy. Therefore, this narrative review aims to provide an updated overview on the bioactive phytochemicals with anti-EMT activity.

CONCLUSION

Among the plant products reviewed, phenylpropanoids were the most investigated at preclinical phase, thus exhibiting a promising potential as anticancer drugs, though an evidence-based clinical efficacy is still lacking.

Activation of the MAPK signaling pathway induces upregulation of pro-apoptotic proteins in the hippocampi of cold stressed adolescent mice

Stress induces many non-specific responses in the hippocampus, especially during adolescence. Low environmental temperature is known to induce stress, but its influence on the hippocampus, especially in adolescent mice is not clear. We compared apoptotic-related protein levels and MAPK signaling pathway activation in hippocampal neurons of adolescent mice under low temperature conditions (4 °C for 12 h) with western blotting and immunohistochemistry. Western bolt results demonstrated that the levels of phospho-JNK, phospho-p38, and cleaved-caspase 3 significantly increased, while the ratio of Bcl-XL/Bax decreased, in the cold stress group. The results of immunohistochemistry (IHC) and Nissl staining demonstrated that the protein optical density of caspase 3 increased and Nissl bodies decreased in the cold stress group compared with controls. Thus, we conclude that cold exposure initiates activation of the MAPK signaling pathway and subsequently induces the upregulation of pro-apoptotic proteins in the hippocampi of adolescent mice. Overall our study reveals the relationship between cold stress and apoptosis in adolescent mice.

A newly synthesized oleanolic acid derivative inhibits the growth of osteosarcoma cells in vitro and in vivo by decreasing c-MYC-dependent glycolysis

Osteosarcoma (OS) is the primary malignant bone tumor with a peak incidence in children and adolescents. However, the little molecular mechanism of pathogenesis has been known and it is urgent to develop new therapeutical strategies to improve outcomes for patients. CDDO-NFM (N-formylmorpholine substituent of CDDO) is a newly synthesized triterpenoid, which is a derivative of oleanolic acid. In this study, we explored whether CDDO-NFM possesses a potential antitumor effect and revealed its molecular mechanism. We found that CDDO-NFM efficiently inhibited cell growth of OS cells and this inhibitory effect was independent of apoptosis-related and cell-cycle-related proteins. CDDO-NFM could decrease the level of glucose uptake, the generation of lactate, and the production of adenosine triphosphate to block the process of glycolysis. In vitro and in vivo cell-based assays showed that CDDO-NFM inhibited glycolysis via degradation of c-MYC rather than activating peroxisome proliferator-activated receptor gamma. Finally, CDDO-NFM could reduce tumor volume and weight with low toxicity, and down-regulate the expression of glycolysis-related enzymes in nude mice. Taken together, these results showed that CDDO-NFM might be a promising antitumor compound.

MicroRNA-650 targets inhibitor of growth 4 to promote colorectal cancer progression via mitogen activated protein kinase signaling

Colorectal cancer (CRC) is the third most common malignant disease globally and causes numerous cancer-associated mortalities; however, the underlying molecular mechanisms remain unresolved. MicroRNAs (miRs) are endogenous noncoding RNAs that regulate post-transcriptional gene silencing by annealing to partially complementary sequences in the 3′-untranslated regions of target mRNAs. In the present study, expression of the tumor suppressor gene inhibitor of growth protein 4 (ING4) in cell lines was investigated using reverse transcription-quantitative polymerase chain reaction and western blotting. miR-650 overexpression promoted CRC cell proliferation and migration by targeting ING4 when the cells were transfected with the miR-650 mimics. Additionally, overexpression of miR-650 increased the epithelial-mesenchymal transition and activation of the Ras homolog gene family member A/Ras-related C3 botulinum toxin GTPase. Extracellular signal-regulated kinases and p38 mitogen-activated protein kinase signaling were markedly activated when miR-650 was increased in CRC cells. Combined, the results indicate the mechanism underlying the miR-650 promotion of CRC progression, and provide promising potential biomarkers for the prognosis and treatment of CRC.

Oleanolic acid induces p53-dependent apoptosis via the ERK/JNK/AKT pathway in cancer cell lines in prostatic cancer xenografts in mice

We evaluated oleanolic acid (OA)-induced anti-cancer activity, apoptotic mechanism, cell cycle status, and MAPK kinase signaling in DU145 (prostate cancer), MCF-7 (breast cancer), U87 (human glioblastoma), normal murine liver cell (BNL CL.2) and human foreskin fibroblast cell lines (Hs 68). The IC50 values for OA-induced cytotoxicity were 112.57 in DU145, 132.29 in MCF-7, and 163.60 in U87 cells, respectively. OA did not exhibit toxicity in BNL CL. 2 and Hs 68 cell lines in our experiments. OA, at 100 µg/mL, increased the number of apoptotic cells to 27.0% in DU145, 27.0% in MCF-7, and 15.7% in U87, when compared to control cells. This enhanced apoptosis was due to increases in p53, cytochrome c, Bax, PARP-1 and caspase-3 expression in DU145, MCF-7 and U87 cell lines. OA-treated DU145 cells were arrested in G2 because of the activation of p-AKT, p-JNK, p21 and p27, and the decrease in p-ERK, cyclin B1 and CDK2 expression; OA-treated MCF-7 cells were arrested in G1 owing to the activation of p-JNK, p-ERK, p21, and p27, and the decrease in p-AKT, cyclin D1, CDK4, cyclin E, and CDK2; and OA-treated U87 cells also exhibited G1 phase arrest caused by the increase in p-ERK, p-JNK, p-AKT, p21, and p27, and the decrease in cyclin D1, CDK4, cyclin E and CDK2. Thus, OA arrested the cell cycle at different phases and induced apoptosis in cancer cells. These results suggested that OA possibly altered the expression of the cell cycle regulatory proteins differently in varying types of cancer.

Long non-coding RNA-mediated regulation of signaling pathways in gastric cancer

Gastric cancer (GC) is one of the most common cancers globally. Because of the high frequency of tumor recurrence, or metastasis, after surgical resection, the prognosis of patients with GC is poor. Therefore, exploring the mechanisms underlying GC is of great importance. Recently, accumulating evidence has begun to show that dysregulated long non-coding RNAs (lncRNAs) participate in the progression of GC via several typical signaling pathways, such as the AKT and MAPK signaling pathways. Moreover, the interactions between lncRNAs and microRNAs appear to represent a novel mechanism in the pathogenesis of GC. This review provides a synopsis of the latest research relating to lncRNAs and associated signaling pathways in GC.

Effects of AQP5 gene silencing on proliferation, migration and apoptosis of human glioma cells through regulating EGFR/ERK/ p38 MAPK signaling pathway

We investigated the effects of aquaporin 5 (AQP5) gene silencing on the proliferation, migration and apoptosis of human glioma cells through regulating the EGFR/ERK/p38MAPK signaling pathway. qRT-PCR was applied to examine the mRNA expressions of AQP5 in five human glioma cell lines. U87-MG, U251 and LN229 cells were selected and assigned into blank, vector, AQP5 siRNA and FlagAQP5 groups. MTT assay was used to measure cell proliferation. Flow cytometry (FCM) with AnnexinV-FITC/PI double staining and PI staining were employed to analyze cell apoptosis and cell cycle respectively. Scratch test was used to detect cell migration. Western blotting was performed to determine the EGFR/ERK/p38 MAPK signaling pathway-related proteins. Results showed that the positive expression of AQP5 in primary glioblastoma was associated with the tumor size and whether complete excision was performed. The mRNA expressions of AQP5 in cell lines of U87-MG, U251 and LN229 were significantly higher than in U373 and T98G. The proliferation rates of U87-MG, U251 and LN229 cells in the AQP5 siRNA group were lower than in the vector and blank groups. The apoptosis rate increased in the AQP5 siRNA group compared with the vector group. Scratch test demonstrated that AQP5 gene silencing could suppress cell migration. Compared with the vector and blank groups, the AQP5 siRNA group showed decreased expressions of the ERK1/2, p38 MAPK, p-ERK1/2 and p-p38 MAPK proteins. AQP5 gene silencing could inhibit the cell proliferation, reduce cell migration and promote the cell apoptosis of U87-MG, U251 and LN229 by suppressing EGFR/ERK/p38 MAPK signaling pathway.

Hypoxia activates enhanced invasive potential and endogenous hyaluronic acid production by glioblastoma cells

Glioblastoma (GBM) is the most common, aggressive, and deadly form of adult brain cancer, and is associated with a short survival rate (median 12-15 months, 5+ year less than 5%). The complex tumor microenvironment includes matrix transitions at the tumor margin, such as gradations in hyaluronic acid (HA). In addition, metabolic stress induced by decreased oxygen content across the tumor may contribute to tumor progression. However, cross-talk between matrix composition and metabolic stress remains unclear. In this study, we fabricated an in vitro brain memetic HA-decorated gelatin hydrogel platform incorporating variable oxygen concentrations to mimic intra-tumoral hypoxia. We observed that EGFR status (wildtype vs. a constitutively active EGFRvIII mutant) of U87 GBM cells affected proliferation and metabolic activity in response to hypoxia and matrix-bound HA. The use of an invasion assay revealed that invasion was significantly enhanced in both cell types under hypoxia. Moreover, we observed compensatory secretion of soluble HA in cases of enhanced GBM cell invasion, consistent with our previous findings using other GBM cell lines. Interestingly, U87 GBM cells adapted to hypoxia by shifting toward a more anaerobic metabolic state, a mechanism that may contribute to GBM cell invasion. Collectively, these data demonstrate that the use of a three-dimensional hydrogel provides a robust method to study the impact of matrix composition and metabolic challenges on GBM cell invasion, a key factor contributing to the most common, aggressive, and deadly form of adult brain cancer.

Isolation and identification of human metabolites from a novel anti-tumor candidate drug 5-chlorogenic acid injection by HPLC-HRMS/MSn and HPLC-SPE-NMR

A novel anti-tumor candidate drug, 5-chlorogenic acid (5-CQA) injection, was used for the treatment of malignant glioma in clinical trial (phase I) in China. The isolation and identification of the metabolites of 5-CQA injection in humans were investigated in the present study. Urine and feces samples obtained after intramuscular administration of 5-CQA injection to healthy adults have been analyzed by high-performance liquid chromatography coupled with high-resolution mass and multiple-stage mass spectrometry (HPLC-HRMS/MSⁿ). No metabolite was detected in human feces; however, in human urine, a total of six metabolites were identified including isomerized 5-CQA (P1 and P2), hydrolyzed 5-CQA (M1and M2), and methylated 5-CQA (M3 and M4). Among them, M3 and M4 were the main metabolites and target analytes for human mass balance study. Additionally, the structure of M3 and M4 was characterized by high-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR), and the results demonstrated that the methoxy group of M3 and M4 was exclusively attributed to C-3' and C-4', respectively. Due to the unavailability of commercial reference, the pure products of M3 and M4 were synthesized by 5-CQA methylation and followed by isolation and purification. Moreover, the potential activity of M3 and M4 on malignant glioma was predicted using a reverse molecular docking analysis on eight malignant glioma-related pathways. The results showed that M3 and M4 had various interactions against malignant glioma-related targets. Our study provides an insight into the metabolism of 5-CQA injection in humans and supports the clinical human mass balance study. Graphical abstract ᅟ.

The Candidate Tumor Suppressor Gene SLC8A2 Inhibits Invasion, Angiogenesis and Growth of Glioblastoma

Glioblastoma is the most frequent and most aggressive brain tumor in adults. Solute carrier family 8 member 2 (SLC8A2) is only expressed in normal brain, but not present in other human normal tissues or in gliomas. Therefore, we hypothesized that SLC8A2 might be a glioma tumor suppressor gene and detected the role of SLC8A2 in glioblastoma and explored the underlying molecular mechanism. The glioblastoma U87MG cells stably transfected with the lentivirus plasmid containg SLC8A2 (U87MG-SLC8A2) and negative control (U87MG-NC) were constructed. In the present study, we found that the tumorigenicity of U87MG in nude mice was totally inhibited by SLC8A2. Overexpression of SLC8A2 had no effect on cell proliferation or cell cycle, but impaired the invasion and migration of U87MG cells, most likely through inactivating the extracellular signal-related kinases (ERK)1/2 signaling pathway, inhibiting the nuclear translocation and DNA binding activity of nuclear factor kappa B (NF-κB), reducing the level of matrix metalloproteinases (MMPs) and urokinase-type plasminogen activator (uPA)-its receptor (uPAR) system (ERK1/2-NF-κB-MMPs/uPA-uPAR), and altering the protein levels of epithelial to mesenchymal transitions (EMT)-associated proteins E-cardherin, vimentin and Snail. In addition, SLC8A2 inhibited the angiogenesis of U87MG cells, probably through combined inhibition of endothelium-dependent and endothelium-nondependent angiogenesis (vascular mimicry pattern). Totally, SLC8A2 serves as a tumor suppressor gene and inhibits invasion, angiogenesis and growth of glioblastoma.

LINC00461, a long non-coding RNA, is important for the proliferation and migration of glioma cells

An increasing number of reports have revealed that long non-coding RNAs are important players in tumorigenesis. Here we showed that long non-coding RNA LINC00461 is highly expressed in glioma tissues compared to non-neoplastic brain tissues. The knockdown of LINC00461 suppressed cyclinD1/A/E expression which led to G0/G1 cell cycle arrest and inhibited cell proliferation in glioma cells. LINC00461 suppression also inhibited glioma cell migration and invasion. The function of LINC00461 in glioma cells is partially mediated by MAPK/ERK and PI3K/AKT signaling pathways as down-regulation of LINC00461 expression suppressed ERK1/2 and AKT activities. Moreover, LINC00461 knockdown decreased expression levels of microRNA miR-9 and flanking genes MEF2C and TMEM161B. Taken together, our results demonstrate that LINC00461 is important for glioma progression affecting cell proliferation, migration and invasion via MAPK/ERK, PI3K/AKT, and possibly other signaling pathways.

Pomolic acid induces apoptosis and inhibits multidrug resistance protein MRP1 and migration in glioblastoma cells

Glioblastoma (GBM), the most aggressive of primary brain tumors, determine short survival and poor quality of life. Therapies used for its treatment are not effective and chemotherapy failure is partially due to multidrug resistance (MDR) mechanisms present in the tumor cells. New therapeutic strategies are needed in order to improve survival in GBM. The present study investigated the activity of the pentacyclic triterpene pomolic acid (PA) in GBM. Pomolic acid decreased the viability and induced apoptosis of GBM cells as demonstrated by DNA fragmentation. It also induced uncoupling of mitochondria membrane potential and activation of caspase-3 and -9. Pomolic acid-induced apoptosis is dependent on reactive oxygen species (ROS) production as it is inhibited by anti-oxidant treatment. Pomolic acid also down-modulated the activity of the multidrug resistance associated protein 1 (MRP1) and inhibited migration of GBM cells. These results show that PA acts on several pathways of GBM drug resistance and therefore may be of potential interest for the treatment of this tumor.

Benzo(a)pyrene enhances the EMT-associated migration of lung adenocarcinoma A549 cells by upregulating Twist1

Benzo(a)pyrene (BaP), an important toxic component of cigarette smoke, can cause lung cancer and lead to the progression of lung cancer. In the present study, we investigated the effect of BaP on the migration of lung adenocarcinoma A549 cells. BaP (1 µM) promoted the migration of A549 cells in a time-dependent manner and upregulated the expression of the Twist family BHLH transcription factor 1 (Twist1). BaP also induced upregulation of the mesenchymal markers N-cadherin and vimentin and downregulation of the epithelial marker E-cadherin. When the expression of Twist1 was knocked down in A549 cells that were treated with BaP for 4 weeks (A549BaP-4w), the expression of Twist1 decreased, which inhibited the migration capacity of A549BaP-4w cells, the expression of N-cadherin and vimentin was downregulated and the expression of E-cadherin was upregulated. In addition, morphological observations of A549BaP-4w cells revealed that the epithelial characteristics of A549 cells became mesenchymal characteristics. When the expression of Twist1 was knocked down, the A549BaP-4w cells were transformed back to cells with epithelial characteristics. In conclusion, the results from the present study indicate that BaP enhances the epithelial-mesenchymal transition-associated migration of lung adenocarcinoma A549 cells by upregulating Twist1.

In vitro antineoplastic effects of brivaracetam and lacosamide on human glioma cells

Background

Epilepsy is a frequent symptom in patients with glioma. Although treatment with antiepileptic drugs is generally effective in controlling seizures, drug-resistant patients are not uncommon. Multidrug resistance proteins (MRPs) and P-gp are over-represented in brain tissue of patients with drug-resistant epilepsy, suggesting their involvement in the clearance of antiepileptic medications. In addition to their anticonvulsant action, some drugs have been documented for cytotoxic effects. Aim of this study was to evaluate possible in vitro cytotoxic effects of two new-generation antiepileptic drugs on a human glioma cell line U87MG.

Methods

Cytotoxicity of brivaracetam and lacosamide was tested on U87MG, SW1783 and T98G by MTS assay. Expression of chemoresistance molecules was evaluated using flow cytometry in U87MG and human umbilical vein endothelial cells (HUVECs). To investigate the putative anti-proliferative effect, apoptosis assay, microRNA expression profile and study of cell cycle were performed.

Results

Brivaracetam and lacosamide showed a dose-dependent cytotoxic and anti-migratory effects. Cytotoxicity was not related to apoptosis. The exposure of glioma cells to brivaracetam and lacosamide resulted in the modulation of several microRNAs; particularly, the effect of miR-195-5p modulation seemed to affect cell cycle, while miR-107 seemed to be implicated in the inhibition of cells migration. Moreover, brivaracetam and lacosamide treatment did not modulate the expression of chemoresistance-related molecules MRPs1-3-5, GSTπ, P-gp on U87MG and HUVECs.

Conclusion

Based on antineoplastic effect of brivaracetam and lacosamide on glioma cells, we assume that patients with glioma could benefit by the treatment with these two molecules, in addition to standard therapeutic options.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-017-0546-9) contains supplementary material, which is available to authorized users.

Autophagy-related gene expression is an independent prognostic indicator of glioma

In this study, we identified 74 differentially expressed autophagy-related genes in glioma patients. Analysis using a Cox proportional hazard regression model showed that MAPK8IP1 and SH3GLB1, two autophagy-related genes, were associated with the prognostic signature for glioma. Glioma patients from the CGGA batches 1 and 2, GSE4412 and TCGA datasets could be divided into high- and low-risk groups with different survival times based on levels of MAPK8IP1 and SH3GLB1 expression. The autophagy-related signature was an independent predictor of survival outcomes in glioma patients. MAPK8IP1 overexpression and SH3GLB1 knockdown inhibited glioma cell proliferation, migration and invasion, and improved Temozolomide sensitivity. These findings suggest autophagy-related genes like MAPK8IP1 and SH3GLB1 could be potential therapeutic targets in glioma.

Transcriptomic and proteomic insight into the effects of a defined European mistletoe extract in Ewing sarcoma cells reveals cellular stress responses

BACKGROUND

The hydrophobic triterpenes, oleanolic and betulinic acid as well as the hydrophilic mistletoe lectins and viscotoxins possess anticancer properties. They do all occur in combination in European mistletoe (Viscum album L.). Commercial Viscum album L. extracts are aqueous, excluding the insoluble triterpenes. We have previously shown that mistletoe lectins and triterpene acids are effective against Ewing sarcoma in vitro, ex vivo and in vivo.

METHODS

We recreated a total mistletoe effect (viscumTT) by combining an aqueous extract (viscum) and a triterpene extract (TT) solubilised with cyclodextrins and analysed the effects of viscumTT and the single extracts on TC-71 Ewing sarcoma cells in vitro by transcriptomic and proteomic profiling.

RESULTS

Treatment with the extracts strongly impacted Ewing sarcoma cell gene and protein expression. Apoptosis-associated and stress-activated genes were upregulated, proteasomal protein abundance enhanced and ribosomal and spliceosomal proteins downregulated. The mechanism of action of viscum, TT and viscumTT in TC-71 and MHH-ES-1 cells suggests the involvement of the unfolded protein response. While viscum and viscumTT extract treatment indicate response to oxidative stress and activation of stress-mediated MAPK signalling, TT extract treatment suggests the involvement of TLR signalling and autophagy.

CONCLUSIONS

Since the combinatory extract viscumTT exerts highly effective pro-apoptotic effects on Ewing sarcoma cells in vitro, this phytopolychemotherapy could be a promising adjuvant therapeutic option for paediatric patients with Ewing sarcoma.

Oleanolic Acid Alters Multiple Cell Signaling Pathways: Implication in Cancer Prevention and Therapy

Nowadays, much attention has been paid to diet and dietary supplements as a cost-effective therapeutic strategy for prevention and treatment of a myriad of chronic and degenerative diseases. Rapidly accumulating scientific evidence achieved through high-throughput technologies has greatly expanded the understanding about the multifaceted nature of cancer. Increasingly, it is being realized that deregulation of spatio-temporally controlled intracellular signaling cascades plays a contributory role in the onset and progression of cancer. Therefore, targeting regulators of oncogenic signaling cascades is essential to prevent and treat cancer. A plethora of preclinical and epidemiological evidences showed promising role of phytochemicals against several types of cancer. Oleanolic acid, a common pentacyclic triterpenoid, is mainly found in olive oil, as well as several plant species. It is a potent inhibitor of cellular inflammatory process and a well-known inducer of phase 2 xenobiotic biotransformation enzymes. Main molecular mechanisms underlying anticancer effects of oleanolic acid are mediated by caspases, 5' adenosine monophosphate-activated protein kinase, extracellular signal-regulated kinase 1/2, matrix metalloproteinases, pro-apoptotic Bax and bid, phosphatidylinositide 3-kinase/Akt1/mechanistic target of rapamycin, reactive oxygen species/apoptosis signal-regulating kinase 1/p38 mitogen-activated protein kinase, nuclear factor-κB, cluster of differentiation 1, CKD4, s6k, signal transducer and activator of transcription 3, as well as aforementioned signaling pathways . In this work, we critically review the scientific literature on the molecular targets of oleanolic acid implicated in the prevention and treatment of several types of cancer. We also discuss chemical aspects, natural sources, bioavailability, and safety of this bioactive phytochemical.

Oleanolic acid induces migration in Mv1Lu and MDA-MB-231 epithelial cells involving EGF receptor and MAP kinases activation

During wound healing, skin function is restored by the action of several cell types that undergo differentiation, migration, proliferation and/or apoptosis. These dynamics are tightly regulated by the evolution of the extra cellular matrix (ECM) contents along the process. Pharmacologically active flavonoids have shown to exhibit useful physiological properties interesting in pathological states. Among them, oleanolic acid (OA), a pentacyclic triterpene, shows promising properties over wound healing, as increased cell migration in vitro and improved wound resolution in vivo. In this paper, we pursued to disclose the molecular mechanisms underlying those effects, by using an in vitro scratch assay in two epithelial cell lines of different linage: non-malignant mink lung epithelial cells, Mv1Lu; and human breast cancer cells, MDA-MB-231. In every case, we observed that OA clearly enhanced cell migration for in vitro scratch closure. This correlated with the stimulation of molecular pathways related to mitogen-activated protein (MAP) kinases, as ERK1,2 and Jun N-terminal kinase (JNK) 1,2 activation and c-Jun phosphorylation. Moreover, MDA-MB-231 cells treated with OA displayed an altered gene expression profile affecting transcription factor genes (c-JUN) as well as proteins involved in migration and ECM dynamics (PAI1), in line with the development of an epithelial to mesenchymal transition (EMT) status. Strikingly, upon OA treatment, we observed changes in the epidermal growth factor receptor (EGFR) subcellular localization, while interfering with its signalling completely prevented migration effects. This data provides a physiological framework supporting the notion that lipophilic plant extracts used in traditional medicine, might modulate wound healing processes in vivo through its OA contents. The molecular implications of these observations are discussed.

Geijigajakyak decoction inhibits the motility and tumorigenesis of colorectal cancer cells

Background

Recent studies report that inflammatory diseases of the large intestine are associated with colorectal cancer. Geijigajakyak Decoction (GJD) has antispasmodic and anti-inflammatory effects on the gastrointestinal tract. Thus, in light of the connection between chronic bowel inflammation and colorectal cancer (CRC), we asked whether GJD inhibits colorectal tumorigenesis.

Methods

The effects of GJD on the viability and proliferation of CRC cells were evaluated using MTT and BrdU assays, respectively. The motility of CRC cells was examined by a Transwell migration/invasion assay and immunoblot analysis was used to examine the signaling pathways associated with migration. A syngeneic Balb/c mice allograft model, in which CT26 cells were injected into the dorsum, was used to evaluate the anti-tumor effects of GJD in vivo.

Results

GJD had no cytotoxic effects against HCT116 CRC cells, although it did inhibit their proliferation. GJD inhibited the migration of HCT116 cells, and suppressed the invasion of HCT116, Caco2, and CSC221 CRC cells. In addition, GJD downregulated the expression of p-JNK and p-p38 MAPK, which are downstream signaling molecules associated with invasiveness. Furthermore, oral administration of GJD (333 mg/kg, twice a day) inhibited tumor growth in a mouse xenograft model.

Conclusions

GJD inhibited the motility of human CRC cells and suppressed tumorigenesis in a mouse model. These results suggest that GJD warrants further study as a potential adjuvant anti-cancer therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1281-z) contains supplementary material, which is available to authorized users.

Inhibition of histamine receptor 3 suppresses glioblastoma tumor growth, invasion, and epithelial-to-mesenchymal transition

Histamine receptor 3 (H3R) is expressed in various tumors and correlated with malignancy and tumor proliferation. However, the role of H3R in tumor invasion and epithelial to mesenchymal transition (EMT) remains unknown. Here, we explored the H3R in the highly invasive glioblastoma (GBM) and U87MG cells. We found that H3R mRNA and protein levels were up-regulated in the GBM and glioma cell lines compared to normal brain tissue and astrocytes. In U87MG cell line, inhibition of H3R by siRNA or the antagonist ciproxifan (CPX) suppressed proliferation, invasiveness, and the expression of EMT activators (Snail, Slug and Twist). In addition, expression of epithelial markers (E-cadherin and ZO-1) was up-regulated and expression of mesenchymal markers (vimentin and N-cadherin) was down-regulated in vitro and in vivo in a xenograft model. In addition, we also showed that inhibition of H3R by siRNA or CPX inactivated the PI3K/Akt and MEK/ERK signaling pathways, while inhibition of Akt or ERK activity with antagonists or siRNAs suppressed H3R agonist (R)-(α)-(-)- methylhistamine dihydrobromide (RAMH) mediated invasion and reorganization of cadherin-household. In conclusion, overexpression of H3R is associated with glioma progression. Inhibition of H3R leads to suppressed invasion and EMT of GBM by inactivating the PI3K/Akt and MEK/ERK pathways in gliomas.

Oleanolic acid induced autophagic cell death in hepatocellular carcinoma cells via PI3K/Akt/mTOR and ROS-dependent pathway

Oleanolic acid (OA) has a wide variety of bioactivities such as hepatoprotective, anti-inflammatory and anti-cancer activity and is used for medicinal purposes in many Asian countries. In the present study, the effect of OA on induction of autophagy in human hepatocellular carcinoma HepG2 and SMC7721 cells and the related mechanisms were investigated. MTT assay showed that OA significantly inhibited HepG2 and SMC7721 cells growth. OA treatment enhanced formation of autophagic vacuoles as revealed by monodansylcadaverine (MDC) staining. At the same time, increasing punctuate distribution of microtubule-associated protein 1 light chain 3 (LC3) and an increasing ratio of LC3-II to LC3-I were also triggered by OA incubation. In addition, OA-induced cell death was signifi cantly inhibited by autophagy inhibitors 3-methyladenine (3-MA) and chloroquine (CQ) pretreatment. And we found out that OA can suppress the PI3K/Akt1/mTOR signaling pathway. Furthermore, our data suggested that OA-triggered autophagy was ROS-dependent as demonstrated by elevated cellular ROS levels by OA treatment. When ROS was cleared by N-acetylcysteine (NAC), OA-induced LC3-II convertsion and cell death were all reversed. Taken together, our results suggest that OA exerts anticancer eff ect via autophagic cell death in hepatocellular carcinoma.

An integrated global chemomics and system biology approach to analyze the mechanisms of the traditional Chinese medicinal preparation Eriobotrya japonica - Fritillaria usuriensis dropping pills for pulmonary diseases

Background

Traditional Chinese medicine (TCM) herbal formulae provide valuable therapeutic strategies. However, the active ingredients and mechanisms of action remain unclear for most of these formulae. Therefore, the identification of complex mechanisms is a major challenge in TCM research.

Methods

This study used a network pharmacology approach to clarify the anti-inflammatory and cough suppressing mechanisms of the Chinese medicinal preparation Eriobotrya japonica – Fritillaria usuriensis dropping pills (ChuanbeiPipa dropping pills, CBPP). The chemical constituents of CBPP were identified by high-quality ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS), and anti-inflammatory ingredients were selected and analyzed using the PharmMapper and Kyoto Encyclopedia of Genes and Genomes (KEGG) bioinformatics websites to predict the target proteins and related pathways, respectively. Then, an RNA-sequencing (RNA-Seq) analysis was carried out to investigate the different expression of genes in the lung tissue of rats with chronic bronchitis.

Results

Six main constituents affected 19 predicted pathways, including ursolic acid and oleanolic acid from Eriobotrya japonica (Thunb.) Lindl. (Eri), peiminine from Fritillaria usuriensis Maxim. (Fri), platycodigenin and polygalacic acid from Platycodon grandiflorum (Jacq.) A. DC. (Pla) and guanosine from Pinellia ternata (Thunb.) Makino. (Pin). Expression of 34 genes was significantly decreased after CBPP treatment, affecting four therapeutic functions: immunoregulation, anti-inflammation, collagen formation and muscle contraction.

Conclusion

The active components acted on the mitogen activated protein kinase (MAPK) pathway, transforming growth factor (TGF)-beta pathway, focal adhesion, tight junctions and the action cytoskeleton to exert anti-inflammatory effects, resolve phlegm, and relieve cough. This novel approach of global chemomics-integrated systems biology represents an effective and accurate strategy for the study of TCM with multiple components and multiple target mechanisms.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-015-0983-y) contains supplementary material, which is available to authorized users.

Oleanolic acid inhibits cell survival and proliferation of prostate cancer cells in vitro and in vivo through the PI3K/Akt pathway

Oleanolic acid (OA) is a naturally occurring pentacyclic triterpenoid and possesses diverse pharmacological activities, including anti-cancer effects that have been confirmed in multiple types of human cancers. However, the potential effect of natural OA on human prostate cancer is still unclear. The present study aimed to explore whether and how OA exerted anti-cancer effects in prostate cancer. Our data showed that OA inhibited cell viability and proliferation, and promoted cell apoptosis and G0/G1 phase cell cycle arrest in prostate cancer PC-3, DU145, and LNCaP cells, in a dose-dependent manner. In addition, OA was found to regulate the expression levels of apoptosis-related and cell cycle-related proteins, as well as the activity of PI3K/Akt pathway, in a dose-dependent manner. Mechanistically, our data revealed that OA exerted anti-cancer effects in vitro in PC-3 and DU145 cells by repressing the PI3K/Akt pathway. In agreement, OA also suppressed the tumor growth of PC-3 cells in vivo via inhibition of the PI3K/Akt pathway. In conclusion, our findings demonstrate the anti-cancer properties of OA in prostate cancer cells, both in vitro and in vivo, and provide the experimental evidence for the use of OA as an adjuvant agent for prostate cancer patients.

E-selectin ligand-1 controls circulating prostate cancer cell rolling/adhesion and metastasis

Circulating prostate cancer (PCa) cells preferentially roll and adhere on bone marrow vascular endothelial cells, where abundant E-selectin and stromal cell-derived factor 1 (SDF-1) are expressed, subsequently initiating a cascade of activation events that eventually lead to the development of metastases. To elucidate the roles of circulating PCa cells' rolling and adhesion behaviors in cancer metastases, we applied a dynamic cylindrical flow-based microchannel device that is coated with E-selectin and SDF-1, mimicking capillary endothelium. Using this device we captured a small fraction of rolling PCa cells. These rolling cells display higher static adhesion ability, more aggressive cancer phenotypes and stem-like properties. Importantly, mice received rolling PCa cells, but not floating PCa cells, developed cancer metastases. Genes coding for E-selectin ligands and genes associated with cancer stem cells and metastasis were elevated in rolling PCa cells. Knock down of E-selectin ligand 1(ESL-1), significantly impaired PCa cells' rolling capacity and reduced cancer aggressiveness. Moreover, ESL-1 activates RAS and MAP kinase signal cascade, consequently inducing the downstream targets. In summary, circulating PCa cells' rolling capacity contributes to PCa metastasis, and that is in part controlled by ESL-1.

Modulation of epithelial-to-mesenchymal cancerous transition by natural products

Metastasis is mainly responsible for poor prognosis of cancer, and epithelial-to-mesenchymal transition (EMT) is a significant process often activated during cancer invasion and metastasis. Therefore EMT could be an effective target of chemotherapy to inhibit cancer metastasis and improve prognosis. Considering that many chemotherapeutics are plant-based, we reviewed recent reports about natural products extracted from plants and cancer EMT prevention.