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Glioblastoma multiforme (GBM) is the most aggressive and mortal primary glioma in adults. Temozolomide (TMZ) is a first-line clinical chemotherapeutic drug. However, TMZ resistance causes treatment failure in patients. Thus, exploring effective adjuvant drugs for GBM is crucial. Piperlongumine (PL), a bioactive alkaloid isolated from long pepper, possesses promising anticancer abilities. However, PL-mediated cytotoxic mechanisms in GBM are still unclear. We attempted to identify PL-regulated networks in suppressing GBM malignancy.PL treatment significantly induced more apoptotic death in several GBM cell lines than in normal astrocytes. Decreased cell invasion, colony generation, and sphere formation, and enhanced TMZ cytotoxicity were found in PL-treated cells. Through RNA sequencing, PL-mediated transcriptomic profiles were established. By intersecting PL-downregulated genes, higher expressing genes in The Cancer Genome Atlas (TCGA) tumor tissues, and risk genes in three different GBM databases, tripartite motif-containing 14 (TRIM14) was selected. Higher TRIM14 expression was correlated with poor patient survival, and it existed in tumor samples, in mesenchymal type of GBM patients, and in GBM cells. PL significantly reduced TRIM14 expression through activating the p38/MAPK pathway. Overexpression or knockdown of TRIM14 influenced cell growth, PL-inhibited cell viability, invasion, colony generation, and sphere formation. Finally, using a gene set enrichment analysis, genes positively correlated with TRIM14 levels were enriched in epithelial-to-mesenchymal transition signaling. TRIM14 overexpression attenuated PL-regulated mesenchymal transition signaling.PL inhibited TRIM14 signaling through activating the p38/MAPK pathway to inhibit GBM malignancy. Our findings may provide better insights and directions for future GBM therapies.

The insulin-like growth factor (IGF)-1 and transforming growth factor (TGF)-β signal pathways are both recognized as important in regulating cancer prognosis, such as the epithelial-to-mesenchymal transition (EMT) and cell invasion. However, cross-talk between these two signal pathways in glioblastoma multiforme (GBM) is still unclear. In the present study, by analyzing data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GSE) 4412, GBM patients with higher IGF-1 levels exhibited poorer survival. Genes positively correlated with IGF-1 were enriched in EMT and TGF-β signal pathways. IGF-1 treatment enhanced mesenchymal marker expressions and GBM cell invasion. A significant positive correlation was observed for IGF-1 with TGF-β1 (TGFB1) or TGF-β receptor 2 (TGFBR2), both of which participate in TGF-β signaling and are risk genes in the GBM process. IGF-1 stimulation promoted both TGFB1 and TGFBR2 expressions. LY2157299, a TGF-β signaling inhibitor, attenuated IGF-1-enhanced GBM cell invasion and mesenchymal transition. By analyzing IGF-1-regulated microRNA (miR) profiles, miR-4286 was found to be significantly downregulated in IGF-1-treated cells and could be targeted to both TGFB1 and TGFBR2. Overexpression of miR-4286 significantly attenuated expressions of the IGF-1-mediated mesenchymal markers, TGFB1 and TGFBR2. Using kinase inhibitors, only U0126 treatment showed an inhibitory effect on IGF-1-reduced miR-4286 and IGF-1-induced TGFB1/TGFBR2 expressions, suggesting that MEK/ERK signaling is involved in the IGF-1/miR-4286/TGF-β signaling axis. Finally, our results suggested that miR-4286 might act as a tumor suppressive microRNA in inhibiting IGF-1-enhanced GBM cell invasion. In conclusion, IGF-1 is connected to TGF-β signaling in regulating the mesenchymal transition and cell invasion of GBM through inhibition of miR-4286. Our findings provide new directions and mechanisms for exploring GBM progression.

An insufficient oxygen supply within the intratumoral environment, also known as hypoxia, induces glioblastoma multiforme (GBM) invasion, stemness, and temozolomide (TMZ) drug resistance. Long noncoding (lnc)RNAs have been reported to be involved in hypoxia and GBM progression. However, their roles in hypoxic GBM malignancy are still unclear. We investigated the mechanisms of hypoxia-mediated lncRNAs in regulating GBM processes. Using The Cancer Genome Atlas (TCGA) and data mining, hypoxia-correlated lncRNAs were identified. A hypoxia-upregulated lncRNA, MIR210HG, locating in nuclear regions, predicted poor prognoses of patients and modulated hypoxia-promoted glioma stemness, TMZ resistance, and invasion. Depletion of hypoxic MIR210HG suppressed GBM and patient-derived cell growth and increased TMZ sensitivity in vitro and vivo. Using RNA sequencing and gene set enrichment analysis (GSEA), MIR210HG-upregulated genes significantly belonged to the targets of octamer transcription factor 1 (OCT1) transcription factor. The direct interaction between OCT1 and MIR210HG was also validated. Two well-established worse prognostic factors of GBM, insulin-like growth factor-binding protein 2 (IGFBP2) and fibroblast growth factor receptor 1 (FGFR1), were identified as downstream targets of OCT1 through MIR210HG mediation in hypoxia. Consequently, the lncRNA MIR210HG is upregulated by hypoxia and interacts with OCT1 for modulating hypoxic GBM, leading to poor prognoses. These findings might provide a better understanding in functions of hypoxia/MIR210HG signaling for regulating GBM malignancy.

Background Long noncoding (lnc)RNAs and glycolysis are both recognized as key regulators of cancers. Some lncRNAs are also reportedly involved in regulating glycolysis metabolism. However, glycolysis-associated lncRNA signatures and their clinical relevance in cancers remain unclear. We investigated the roles of glycolysis-associated lncRNAs in cancers. Methods Glycolysis scores and glycolysis-associated lncRNA signatures were established using a single-sample gene set enrichment analysis (GSEA) of The Cancer Genome Atlas pan-cancer data. Consensus clustering assays and genomic classifiers were used to stratify patient subtypes and for validation. Fisher’s exact test was performed to investigate genomic mutations and molecular subtypes. A differentially expressed gene analysis, with GSEA, transcription factor (TF) activity scoring, cellular distributions, and immune cell infiltration, was conducted to explore the functions of glycolysis-associated lncRNAs. Results Glycolysis-associated lncRNA signatures across 33 cancer types were generated and used to stratify patients into distinct clusters. Patients in cluster 3 had high glycolysis scores and poor survival, especially in bladder carcinoma, low-grade gliomas, mesotheliomas, pancreatic adenocarcinomas, and uveal melanomas. The clinical significance of lncRNA-defined groups was validated using external datasets and genomic classifiers. Gene mutations, molecular subtypes associated with poor prognoses, TFs, oncogenic signaling such as the epithelial-to-mesenchymal transition (EMT), and high immune cell infiltration demonstrated significant associations with cluster 3 patients. Furthermore, five lncRNAs, namely MIR4435-2HG, AC078846.1, AL157392.3, AP001273.1, and RAD51-AS1, exhibited significant correlations with glycolysis across the five cancers. Except MIR4435-2HG, the lncRNAs were distributed in nuclei. MIR4435-2HG was connected to glycolysis, EMT, and immune infiltrations in cancers. Conclusions We identified a subgroup of cancer patients stratified by glycolysis-associated lncRNAs with poor prognoses, high immune infiltration, and EMT activation, thus providing new directions for cancer therapy.

DNA damage-inducible transcript 4 (DDIT4) is known to participate in various cancers, including glioblastoma multiforme (GBM). However, contradictory roles of DDIT4 exist in inducing cell death and possessing anti-apoptotic functions against cancer progression. Herein, we investigated DDIT4 signaling in GBM and temozolomide (TMZ) drug resistance. We identified that TMZ induced DDIT4 upregulation, leading to desensitization against TMZ cytotoxicity in GBM cells. Higher DDIT4 levels were found in glioma cells and mesenchymal-type GBM patients, and these higher levels were positively correlated with mesenchymal markers. Furthermore, patients with lower DDIT4 levels, especially O-6-methylguanine-DNA methyltransferase (MGMT)-methylated patients, exhibited better TMZ therapeutic efficacy. We determined that higher levels of 5 DDIT4-associated downstream genes, including SLC2A3 (also known as glucose transporter 3 (GLUT3)), can be used to predict a poor prognosis. Among these 5 genes, only GLUT3 was upregulated in both TMZ-treated and DDIT4-overexpressing cells. DDIT4-mediated GLUT3 expression was also identified, and its expression decreased TMZ’s cytotoxicity. A significant correlation existed between DDIT4 and GLUT3. DDIT4 signaling was found to be involved in both glycolytic and autophagic pathways. However, GLUT3 only participated in the exhibition of DDIT4-mediated stemness, resulting from glycolytic regulation, but not in DDIT4-mediated autophagic signaling. Finally, we identified TMZ-upregulated activating transcription factor 4 (ATF4) as an upstream regulator of DDIT4-mediated GLUT3/stemness signaling and autophagy. Consequently, ATF4/DDIT4 signaling was connected to both autophagy and GLUT3-regulated stemness, which are involved in TMZ drug resistance and the poor prognoses of GBM patients. Targeting DDIT4/GLUT3 signaling might be a new direction for glioma therapy. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13311-019-00826-0) contains supplementary material, which is available to authorized users.

Imatinib (IM) is a first-line therapeutic drug for chronic myeloid leukemia (CML), a hematological disease. Mutations in the BCR-ABL domain increase formation of IM resistance in CML. However, not all patients are BCR-ABL domain-mutant dependent. Investigating non-mutant mechanisms in the development of acquired IM resistance is a critical issue. We explored the mechanisms which influence IM efficacy and resistance in CML. Higher protective autophagy was identified in IM-resistant K562 (K562R) cells. Inhibition of autophagy by the inhibitors, chloroquine and 3-methyladenine, enhanced IM's efficacy in K562R cells. In addition, microRNA (miR)-199a/b-5p were downregulated in K562R cells compared to parent cells. Overexpression of miR-199a/b-5p reduced autophagy and induced cell apoptosis, resulting in enhanced IM's efficacy in K562R cells. Moreover, expression levels of the Wingless-type MMTV integration site family member 2 (WNT2), a positive regulator of autophagy, were significantly higher in K562R cells, and it was validated as a direct target gene of miR-199a/b-5p. Overexpressions of miR-199a/b-5p inhibited WNT2 downstream signaling. Furthermore, overexpression and knockdown of WNT2 influenced autophagy formation and CML drug sensitivity to IM. Overexpression of WNT2 could also reverse miR-199a/b-5p-enhanced IM efficacy in K562R cells. These results emphasized that miR-199a/b-5p inhibited autophagy via repressing WNT2 signaling and might provide novel therapeutic strategies for future IM-resistant CML therapy and drug development.

Flavonoids are well-known antioxidants and have shown the ability to prevent tumor formation and recurrence. Especially in dietary flavonoids, they have provided convenience and consistence of intake for long-term prevention of tumor formation. Previous reports suggested that S100 calcium-binding protein A7 (S100A7) might activate epithelial&ndash, mesenchymal transition (EMT) signaling and promote the metastasis of tumor cells, however, the regulatory signaling was unclear. In this study, we found that S100A7 was highly expressed in cancer cells and could be reduced by luteolin (Lu) and quercetin (Qu) through Src/Stat3 signaling. We found that the protein levels of S100A7, phosphorylated Src (p-Src), and p-Stat3 were increased in A431-III cells. Flavonoids Lu and Qu reduce protein levels of p-Src, p-Stat3 and S100A7 in A431-III cells. Treatment of A431-III cells with Src inhibitor SU6656 and Stat3 inhibitor S3I-201 also reduced the protein levels of S100A7. Transactivation activity of 5&prime, upstream regions of S100A7 was activated by Stat3 but was reduced by treatment with Lu, Qu, SU6656 and S3I-201. The treatment also reduced the migratory and invasive abilities of A431-III cells. In a further analysis of EMT markers, the protein level of E-cad increased and that of Twist decreased after treatment with the inhibitors and flavonoids. Overexpression of S100A7 decreased the protein level of E-cad and increased the Twist level, whereas knockdown of S100A7 had the opposite effects. Treatment with S3I-201, Lu and Qu, compared to the control, were found to decrease metastasis of tumor cells in zebrafish larvae. These results suggest that Lu and Qu may inhibit Src/Stat3/S100A7 signaling to reduce tumorigenesis of cancer cells.

Glioblastoma multiforme is the most common brain tumor in adults. Because of its highly invasive nature, it is not easy to treat, resulting in high mortality rates. Stromal interacting molecule 1 (Stim1) plays important roles in regulating store-operated Ca2+ entry, and controls invasion by cancer cells. However, the mechanisms and functions of Stim1 in glioma progression are still unclear. In this study, we investigated the effects of targeting Stim1 expression on glioma cell invasion. By analyzing profiles of glioblastoma multiforme patients from RNA-sequencing data in The Cancer Genome Atlas, higher expression levels of STIM1 were correlated with the poor survival. Furthermore, signaling pathways associated with tumor malignancy, including the epithelial-to-mesenchymal transition (EMT), were activated in patients with high STIM1 expression according to gene set enrichment analyses. Higher Stim1 levels were found in glioma cells compared to human astrocytes, and these higher levels enhanced glioma cell invasion. Xanthohumol (XN), a prenylated flavonoid extracted from the hop plant Humulus lupulus L. (Cannabaceae), significantly reduced cell invasion through inhibiting Stim1 expression. From an micro(mi)RNA array analysis, miR-4725-3p was up-regulated by XN treatment. Over-expression of miR-4725-3p inhibited glioma cell invasion via directly targeting the 3'-untranslated region of STIM1. The extracellular signal-regulated kinase/c-Fos pathway was also validated to participate in XN-up-regulated miR-4725-3p expression according to promoter and chromatin immunoprecipitation assays. These results emphasize that miR-4725-3p-inhibited STIM1 signaling is involved in XN-attenuated glioma cell invasion. These findings may provide insights into novel therapeutic strategies for future glioblastoma therapy and drug development. Open Data: Materials are available on https://cos.io/our-services/open-science-badges/ https://osf.io/93n6m/.

Flavonoids luteolin and quercetin can inhibit growth and metastasis of cancer cells. In our previous report, luteolin and quercetin was shown to block Akt/mTOR/c-Myc signaling. Here, we found luteolin and quercetin reduced protein level and transactivation activity of RPS19 in A431-III cells, which is isolated from parental A431 (A431-P) cell line. Further investigation the inhibitory mechanism of luteolin and quercetin on RPS19, we found c-Myc binding sites on RPS19 promoter. The Akt inhibitor LY294002, mTOR inhibitor rapamycin and c-Myc inhibitor 10058-F4 significantly suppressed RPS19 expression and transactivation activities. Overexpression and knockdown of c-Myc in cancer cells show RPS19 expression was regulated by c-Myc. Furthermore, Knockdown and overexpression of RPS19 was used to analyze of the function of RPS19 in cancer cells. The epithelial-mesenchymal transition (EMT) markers and metastasis abilities of cancer cells were also regulated by RPS19. These data suggest that luteolin and quercetin might inhibit metastasis of cancer cells by blocking Akt/mTOR/c-Myc signaling pathway to suppress RPS19-activated EMT signaling. Keywords: Luteolin, Quercetin, c-Myc, RPS19, EMT

The tumor microenvironment plays an important role in tumor initiation and progression. It is well documented that nicotine participates in cigarette smoking-related malignancies. Previous studies focused on the effects of nicotine on tumor cells; however, the role of the microenvironment in nicotine-mediated tumorigenesis is poorly understood. Herein, we investigated the effect and molecular mechanism of nicotine on fibroblasts and its contribution to breast cancer. We found that nicotine induced the epithelial-mesenchymal transition (EMT) of breast cancer cells and promoted activation of fibroblasts. Interestingly, conditioned medium from nicotine-activated fibroblasts (Nic-CM) had a greater impact on promoting the EMT and migratory capability toward cancer cells than did treatment with nicotine alone. Production of connective tissue growth factor (CTGF) and transforming growth factor (TGF)-β by nicotine-treated fibroblasts was demonstrated to be crucial for promoting the EMT and cancer cell migration, and blocking of CTGF and TGF-β in Nic-CM-suppressed tumor motility. Moreover, nicotine induced expressions of CTGF, and TGF-β in fibroblasts as identified through α7 nicotinic acetylcholine receptor (nAChR)-dependent activation of the AKT/TAZ signaling mechanism. Together, our data showed for the first time that activation of fibroblasts is largely responsible for accelerating smoking-mediated breast cancer progression.

Aims Immune checkpoints regulate immunity to prevent autoimmunity and protect the host from damage during pathogenic infection. They also participate in subverting immune surveillance and promote antitumor immunity in cancers. Although immunotherapy improves clinical outcomes, not all cancer patients experience expected responses after therapy. Hence, it would be meaningful to explore crucial immune checkpoints in cancers for future immunotherapies. Methods and key findings By analyzing pan-cancer data in The Cancer Genome Atlas (TCGA), cluster of differentiation 276 (CD276), also known as B7H3, was found to be a risk gene in several cancers. A positive correlation existed between CD276 and natural killer (NK) cell infiltration. Overexpression of CD276 attenuated NK cell-mediated cell killing. Furthermore, CD276 levels showed a significant negative association with microRNA (miR)-29c-3p. Overexpression of miR-29c-3p rescued CD276-reduced NK cell cytotoxicity. According to gene set enrichment analyses, CD276-associated genes were found to be enriched in genes that targeted Myc. A negative correlation existed between miR-29 expression and Myc activity. CD276 enhanced Myc phosphorylation levels while suppressing miR-29c-3p expression. In contrast, miR-29c-3p inhibited CD276 expression, leading to reduced Myc activity. Myc suppressed miR-29c-3p expression while promoting CD276 upregulation. Significance These findings suggest that a negative regulatory loop among CD276, Myc, and miR-29c-3p influences cancer cells against NK cell cytotoxicity.

Mutation of KRAS in non-small-cell lung cancer (NSCLC) shows a poor response to epidermal growth factor receptor (EGFR) inhibitors and chemotherapy. Currently, there are no direct anti-KRAS therapies available. Thus, new strategies have emerged for targeting KRAS downstream signaling. Panobinostat is a clinically available histone deacetylase inhibitor for treating myelomas and also shows potentiality in NSCLC. However, the therapeutic efficacy of panobinostat against gefitinib-resistant NSCLC is unclear. In this study, we demonstrated that panobinostat overcame resistance to gefitinib in KRAS-mutant/EGFR-wild-type NSCLC. Combined panobinostat and gefitinib synergistically reduced tumor growth in vitro and in vivo. Mechanistically, we identified that panobinostat-but not gefitinib-inhibited TAZ transcription, and the combination of panobinostat and gefitinib synergistically downregulated TAZ and TAZ downstream targets, including EGFR and EGFR ligand. Inhibition of TAZ by panobinostat or short hairpin RNA sensitized KRAS-mutant/EGFR-wild-type NSCLC to gefitinib through abrogating AKT/mammalian target of rapamycin (mTOR) signaling. Clinically, TAZ was positively correlated with EGFR signaling, and coexpression of TAZ/EGFR conferred a poorer prognosis in lung cancer patients. Our findings identify that targeting TAZ-mediated compensatory mechanism is a novel therapeutic approach to overcome gefitinib resistance in KRAS-mutant/EGFR-wild-type NSCLC.

Platelet‐derived growth factor (PDGF) can promote vascular smooth muscle cells (VSMCs) to switch from the quiescent contractile phenotype to synthetic phenotype, which contributes to atherosclerosis. We aimed to investigate the role of microRNA let‐7g in phenotypic switching. Bioinformatics prediction was used to find let‐7g target genes in the PDGF/mitogen‐activated protein kinase kinase kinase 1 (MEKK1)/extracellular signal‐regulated kinase (ERK)/Krüppel‐like factor‐4 (KLF4) signalling pathway that affects VSMC phenotypic switching. The luciferase reporter assay and let‐7g transfection were used to confirm let‐7g target genes. Two contractile proteins alpha‐smooth muscle actin (α‐SMA) and calponin were VSMC‐specific genes and were measured as the indicators for VSMC phenotype. Lentivirus carrying the let‐7g gene was injected to apolipoprotein E knockout (apoE−/−) mice to confirm let‐7g's effect on preventing atherosclerosis. Through the PDGF/MEKK1/ERK/KLF4 signalling pathway, PDGF‐BB can inhibit α‐SMA and calponin. The PDGFB and MEKK1 genes were predicted to harbour let‐7g binding sites, which were confirmed by our reporter assays. Transfection of let‐7g to VSMC also reduced PDGFB and MEKK1 levels. Moreover, we showed that let‐7g decreased phosphorylated‐ERK1/2 while had no effect on total ERK1/2. KLF4 can reduce VSMC‐specific gene expression by preventing myocardin–serum response factor (SRF) complex from associating with these gene promoters. The immunoprecipitation assay showed that let‐7g decreased the interaction between KLF4 and SRF. Further experiments demonstrated that let‐7g can increase α‐SMA and calponin levels to maintain VSMC in the contractile status. Injection of lentivirus carrying let‐7g gene increased let‐7g's levels in aorta and significantly decreased atherosclerotic plaques in the apoE−/− mice. We demonstrated that let‐7g reduces the PDGF/MEKK1/ERK/KLF4 signalling to maintain VSMC in the contractile status, which further reduce VSMC atherosclerotic change.

Glioblastoma multiforme (GBM) is the high-grade primary glioma in adults. Temozolomide (TMZ), an alkylating agent of the imidazotetrazine series, is a first-line chemotherapeutic drug for clinical therapy. However, the expense of TMZ therapy and increasing drug resistance to TMZ decreases its therapeutic effects. Therefore, our aim was to investigate the detailed molecular mechanisms of TMZ-mediated cytotoxicity to enhance the efficacy of TMZ in clinical GBM therapy. First, TMZ-mediated gene expression profiles and networks in U87-MG cells were identified by transcriptome microarray and bioinformatic analyses. Cation transport regulator-like protein 1 (CHAC1) was the most highly TMZ-upregulated gene. Overexpression and knockdown of CHAC1 expression significantly influenced TMZ-mediated cell viability, apoptosis, caspase-3 activation, and poly(ADP ribose) polymerase (PARP) degradation. The c-Jun N-terminal kinase (JNK)1/c-JUN pathway was identified to participate in TMZ-upregulated CHAC1 expression via transcriptional control. Furthermore, CHAC1 levels were significantly decreased in GBM cell lines, TCGA array data, and tumor tissues. Overexpression of CHAC1 enhanced glioma apoptotic death via caspase-3/9 activation, PARP degradation, autophagy formation, reactive oxygen species generation, increased intracellular calcium, and loss of the mitochondria membrane potential. Finally, we also identified that TMZ significantly reduced Notch3 levels, which are upregulated in gliomas. TMZ also induced CHAC1 to bind to the Notch3 protein and inhibit Notch3 activation, resulting in attenuation of Notch3-mediated downstream signaling pathways. These results emphasize that CHAC1-inhibited Notch3 signaling can influence TMZ-mediated cytotoxicity. Our findings may provide novel therapeutic strategies for future glioblastoma therapy.

We previously reported that the dietary flavonoids, luteolin and quercetin, might inhibit the invasiveness of cervical cancer by reversing epithelial-mesenchymal transition (EMT) signaling. However, the regulatory mechanism exerted by luteolin and quercetin is still unclear. This study analyzed the invasiveness activation by ubiquitin E2S ligase (UBE2S) through EMT signaling and inhibition by luteolin and quercetin. We found that UBE2S expression was significantly higher in highly invasive A431 subgroup III (A431-III) than A431-parental (A431-P) cells. UBE2S small interfering (si)RNA knockdown and overexpression experiments showed that UBE2S increased the migratory and invasive abilities of cancer cells through EMT signaling. Luteolin and quercetin significantly inhibited UBE2S expression. UBE2S showed a negative correlation with von Hippel-Lindau (VHL) and a positive correlation with hypoxia-induced factor (Hif)-1α. Our findings suggest that high UBE2S in malignant cancers contributes to cell motility through EMT signaling and is reversed by luteolin and quercetin. UBE2S might contribute to Hif-1α signaling in cervical cancer. These results show the metastatic inhibition of cervical cancer by luteolin and quercetin through reducing UBE2S expression, and provide a functional role for UBE2S in the motility of cervical cancer. UBE2S could be a potential therapeutic target in cervical cancer.

Xanthohumol (XN), a prenylated chalcone extracted from hop plant Humulus lupulus L. (Cannabaceae), has potential for cancer therapy, including gliomas. Micro (mi)RNAs are small noncoding RNAs that control gene expression. Several miRNAs have been identified to participate in regulating glioma development. However, no studies have demonstrated whether miRNA is involved in XN cytotoxicity resulting in glioma cell death. This study investigated the effects of XN-mediated miRNA expression in activating apoptotic pathways in glioblastoma U87 MG cells. First, we found that XN significantly reduced cell viability and induced apoptosis via pro-caspase-3/8 cleavage and poly(ADP ribose) polymerase (PARP) degradation. We also identified that pro-caspase-9 cleavage, Bcl2 family expression changes, mitochondrial dysfunction, and intracellular ROS generation also participated in XN-induced glioma cell death. With a microarray analysis, miR-204-3p was identified as the most upregulated miRNA induced by XN cytotoxicity. The extracellular signal-regulated kinase (ERK)/c-Fos pathway was validated to participate in XN-upregulated miR-204-3p expression. With a promoter assay and ChIP analysis, we found that c-Fos dose-dependently bound to the miR-204-3p gene promoter region. Furthermore, miR-204-3p levels decreased in several glioma cell lines compared to astrocytes. Overexpression of miR-204-3p enhanced glioma cell apoptosis. IGFBP2, an upregulated regulator of glioma proliferation, was validated by a TCGA analysis as a direct target gene of miR-204-3p. XN's inhibition of the IGFBP2/AKT/Bcl2 pathway via miR-204-3p targeting played a critical role in mediating glioma cell death. These results emphasized that the XN-mediated miR-204-3p network may provide novel therapeutic strategies for future glioblastoma therapy and drug development.

Temozolomide (TMZ) is a first-line alkylating agent for glioblastoma multiforme (GBM). Clarifying the mechanisms inducing TMZ insensitivity may be helpful in improving its therapeutic effectiveness against GBM. Insulin-like growth factor (IGF)-1 signaling and micro (mi)RNAs are relevant in mediating GBM progression. However, their roles in desensitizing GBM cells to TMZ are still unclear. We aimed to identify IGF-1-mediated miRNA regulatory networks that elicit TMZ insensitivity for GBM. IGF-1 treatment attenuated TMZ cytotoxicity via WNT/β-catenin signaling, but did not influence glioma cell growth. By miRNA array analyses, 93 upregulated and 148 downregulated miRNAs were identified in IGF-1-treated glioma cells. miR-513a-5p from the miR-513a-2 gene locus was upregulated by IGF-1-mediated phosphoinositide 3-kinase (PI3K) signaling. Its elevated levels were also observed in gliomas versus normal cells, in array data of The Cancer Genome Atlas (TCGA), and the GSE61710, GSE37366, and GSE41032 datasets. In addition, lower levels of neural precursor cell-expressed developmentally downregulated 4-like (NEDD4L), an E3 ubiquitin protein ligase that inhibits WNT signaling, were found in gliomas by analyzing cells, arrays, and RNA sequencing data of TCGA glioma patients. Furthermore, a negative correlation was identified between miR-513a-5p and NEDD4L in glioma. NEDD4L was also validated as a direct target gene of miR-513a-5p, and it was reduced by IGF-1 treatment. Overexpression of NEDD4L inhibited glioma cell viability and reversed IGF-1-repressed TMZ cytotoxicity. In contrast, miR-513a-5p significantly affected NEDD4L-inhibited WNT signaling and reduced TMZ cytotoxicity. These findings demonstrate a distinct role of IGF-1 signaling through miR-513a-5p-inhibited NEDD4L networks in influencing GBM's drug sensitivity to TMZ.

Temozolomide (TMZ) is a first-line chemotherapeutic agent used against glioblastoma multiforme (GBM), but this disease exhibits recurrence and high lethality. Therefore, it is critical to explore biomarkers which involve in drug resistance and can be represented as different therapeutic effects after a diagnosis. We attempted to investigate the underlying variably expressed genes that contribute to the formation of resistance to TMZ. We analyzed gene and microRNA (miR) data from GBM patients in The Cancer Genome Atlas (TCGA) database to identify genetic factors associated with poor TMZ efficacy. By conducting a gene set enrichment analysis (GSEA), the epithelial-to-mesenchymal transition (EMT) was associated with poor TMZ responses. To identify roles of microRNAs in regulating TMZ resistance, a differential microRNA analysis was performed in TMZ-treated GBM patients. Downregulation of miR-140 was significantly correlated with poor survival. By integrating TCGA transcriptomic data and genomics of drug sensitivity in cancer (GDSC), cathepsin B (CTSB) was inversely associated with miR-140 expression and poor TMZ efficacy. By a pan-cancer analysis, both miR-140 and CTSB were found to be prognostic factors in other cancer types. We also identified that CTSB was a direct target gene of miR-140. Overexpression of miR-140 reduced CTSB levels, enhanced TMZ cytotoxicity, suppressed the mesenchymal transition, and influenced CTSB-regulated tumor sphere formation and stemness marker expression. In contrast, overexpression of CTSB decreased TMZ-induced glioma cell death, promoted the mesenchymal transition, and attenuated miR-140-increased TMZ cytotoxicity. These findings provide novel targets to increase the therapeutic efficacy of TMZ against GBM.

Because of innumerable cancer sequencing projects, abundant transcriptome expression profiles together with survival data are available from the same patients. Although some expression signatures for prognosis or pathologic staging have been identified from these data, systematically discovering such kind of expression signatures remains a challenge. To address this, we developed TACCO (Transcriptome Alterations in CanCer Omnibus), a database for identifying differentially expressed genes and altered pathways in cancer. TACCO also reveals miRNA cooperative regulations and supports construction of models for prognosis. The resulting signatures have great potential for patient stratification and treatment decision-making in future clinical applications. TACCO is freely available at http://tacco.life.nctu.edu.tw/.

Reactive oxygen species (ROS) homeostasis is maintained at a higher level in cancer cells, which promotes tumorigenesis. Oxidative stress induced by anticancer drugs may further increase ROS to promote apoptosis, but can also enhance the metastasis of cancer cells. The effects of ROS homeostasis on cancer cells remain to be fully elucidated. In the present study, the effect of a reduction in manganese superoxide dismutase (MnSOD) on the migration and invasion of A431 cells was investigated. Our previous micro‑assay data revealed that the mRNA expression of MnSOD was higher in the invasive A431‑III cell line compared with that in the parental A431 cell line (A431‑P). In the present study, high protein levels of MnSOD and H2O2 production were observed in A431‑III cells; however, catalase protein levels were significantly lower in A431‑III cells compared with those in the A431‑P cell line. The knockdown of MnSOD increased H2O2 levels, enzyme activity, the mRNA levels of matrix metalloproteinase‑1, ‑2 and ‑9, and the migratory and invasive abilities of the cells. Inducing a reduction in H2O2 using diphenyleneiodonium (DPI) and N‑acetyl‑l‑cysteine decreased the migratory abilities of the cell lines, and DPI attenuated the migratory ability that had been increased by MnSOD small interfering RNA knockdown. Luteolin (Lu) and quercetin (Qu) increased the expression of catalase and reduced H2O2 levels, but without an observed change in the protein levels of MnSOD. Taken together, these data suggest that reduced MnSOD may induce ROS imbalance in cells and promote the metastatic ability of cancer cells. Lu and Qu may attenuate these processes and may be promising potential anticancer agents.

The phthalate plasticizer, di(2-ethyl-hexyl) phthalate (DEHP), and its derived metabolites are common anthropogenic environmental toxins, which are known to act as endocrine disruptors. Numerous studies have associated DEHP with disruption of sex hormones, abnormal development of reproductive organs, allergies, and inflammation. Its role in promoting inflammation has been reported by both human epidemiological and animal studies. In stomach tissue, chronic inflammation is known to accompany mucosal damage, and pave the way to gastritis, stomach ulcers, and ultimately gastric cancer. Eastern Asian populations possess the highest gastric cancer incidences in the world. Coincidentally, East Asia is one of the world's major sites for plastics manufacture and export. Thus, possible correlations between DEHP, a common plasticizer, and gastric cancer are of great interest. Our study revealed several critical findings. First, even at very low dosage, mimicking the residual plasticizer exposure, detrimental effects of DEHP on gastric cells can be detected. Second, gastric cells treated with DEHP increased cyclooxygenase-2 (COX-2) in a time-dependent manner. Third, promoter deletion studies revealed a critical role of nuclear factor-kappa B (NF-κB) for COX-2 gene responses. Finally, our results indicated that a low concentration of DEHP is able to trigger COX-2 activation via the extracellular signal-regulated kinase (ERK1/2) and NF-κB signaling pathway. Taken together, we demonstrate that very low doses of DEHP enhance the expression of the prototypical inflammatory gene, COX-2, in gastric cancer cells via ERK1/2 and NF-κB activation. This study provides important insights into the inflammatory process and damages associated with phthalate plasticizers exposure.

Tumor-infiltrating lymphocytes are related to positive clinical prognoses in numerous cancer types. Programmed death ligand 1 (PD-L1), a mediator of the PD-1 receptor, plays an inhibitory role in cancer immune responses. PD-L1 upregulation can impede infiltrating T-cell functions in lung adenocarcinoma (LUAD), a lung cancer subtype. However, associations between the expression of PD-L1 and infiltration of B cells (a major immunoregulatory cell) remain unknown. Therefore, we investigated the role of infiltrating B cells in LUAD progression and its correlation with PD-L1 expression. The Cancer Genome Atlas (TCGA) LUAD data set was used to explore associations among B-cell infiltration, PD-L1 expression, clinical outcome, and gene landscape. Gene set enrichment analysis was used to explore putative signaling pathways and candidate genes. The drug enrichment analysis was used to identify candidate genes and the related drugs. We found that high B-cell infiltration was correlated with better prognoses; however, PD-L1 may interfere with the survival advantage in patients with high B-cell infiltration. The gene landscape was characterized comprehensively, with distinct PD-L1 levels in cell populations with high B-cell infiltration. We obtained five upregulated signaling pathways from the gene landscape: apoptosis, tumor necrosis factor (TNF)-α signaling via nuclear factor (NF)-κB, apical surface, interferon-α response, and KRAS signaling. Moreover, four candidate genes and their related target drugs were also identified, namely interleukin-2β receptor (IL2RB), IL-2γ receptor (IL2RG), Toll-like receptor 8 (TLR8), and TNF. These findings suggest that tumor-infiltrating B cells could act as a clinical factor in anti-PD-L1 immunotherapy for LUAD.

Colon cancer is the third most common cancer in the world and the second most common cause of cancer-related mortality. Molecular biomarkers for colon cancer have undergone vigorous discovery and validation. Recent studies reported that overexpression of podocalyxin-like protein 1 (PODXL) is associated with distant metastasis and poor prognosis across several types of malignancies. Its role and underlying molecular mechanism, however, are not yet fully understood. In the present study, we revealed that the Hippo transducer, the transcriptional coactivator with PDZ-binding motif (TAZ), acts as a downstream mediator of PODXL in colon cancer. Inhibition of PODXL resulted in the suppression of TAZ signaling and the downregulation of Hippo downstream genes. Moreover, PODXL plays a critical role in cancer stemness, invasiveness, and sensitivity to chemotherapies in colon cancer HCT15 cells. Notably, expression of PODXL showed a positive correlation with stem-like and epithelial-mesenchymal transition (EMT) core signatures, and was associated with poor survival outcomes in patients with colon cancer. These findings provide novel insights into the molecular mechanism of PODXL-mediated tumorigenesis in colon cancer.

Hyperlipidemia, including the oxidized low-density lipoprotein (oxLDL) accumulation, is a risk and highly associated with the development of cancers and cardiovascular diseases. microRNA-210 (miR-210), a hypoxia-responsive microRNA regulated by HIF-1α, has been implicated in cancer and cardiovascular disease formation. Furthermore, Bioinformatics analysis revealed that the promoter of the miR-210 gene contains CpG-rich regions. It is unclear whether miR-210 expression could be epigenetically regulated in these disease progresses. The study aimed to explore the relationships between lipid and miR-210 in the context of cardiovascular disease and gastrointestinal cancer. We demonstrated oxLDL can decrease methylation in the miR-210 promoter to up-regulate miR-210. HIF-1α can bind to miR-210 promoter, but this HIF-1α binding site can be blocked by methylation. We showed that subjects of carotid atherosclerosis, stroke patients and cancer patients had hypomethylation in the miR-210 promoter, especially the HIF-1α binding site. Furthermore, miR-210 can directly inhibit sprouty-related EVH1 domain 2 (SPRED2) expressions, and SPRED2 reduces cell migration via ERK/c-Fos/MMPs pathways. Increased miR-210 and reduced SPRED2 levels were found in aorta of mice under high-fat diet and tumor tissues, which implied that miR-210 can be an underlying mechanism to explain oxLDL as a common risk factor for cardiovascular disease and gastrointestinal cancer.

The prognosis of glioblastoma remains poor, even treatment with surgery, radiation, or chemotherapy. Therefore, it is still important to develop a new strategy for treatment of glioblastoma. Previous reports demonstrated that rRNA is produced at abnormally high levels in tumor cells. Nuclear export of all non-coding RNAs are known to depend on RanGTPase system. Hydrolyzation of RanGTP-RNA complex by RanGTPase activating protein 1 (RanGAP1) releases RNA from nucleus to cytoplasm. Therefore, inhibition of RNA transportation would be a useful strategy to affect cancer cell fate. In this study, 5-30 μM of oridonin, a natural diterpenoid compound isolated from the traditional Chinese medicine, Rabdosia rubescens, induced U87MG glioma cell apoptosis and RNA accumulation in nucleus at 12h-time point. Before U87MG cell apoptosis, the RanGAP1 protein amount decreased and RanGTP accumulated in nucleus as respectively determined by immunoprecipitation and immunofluorescence, suggesting that decrease of RanGAP1 may result in nuclear entrapment of RanGTP and RNA, and then induce U87MG cell death. In contrast, over-expression of the RanGAP1 protein reversed oridonin-induced U87MG cell apoptosis. Hence, we demonstrated that downregulation of the RanGAP1 protein level by oridonin may result in RNA accumulation in nucleus via nuclear entrapment of RanGTP which eventually led to the apoptosis of glioma cells.

The insulin-like growth factor (IGF)-1 signaling is relevant in regulating cell growth and cytokine secretions by glioblastomas. MicroRNAs determine the cell fate in glioblastomas. However, relationships between IGF-1 signaling and miRNAs in glioblastoma pathogenesis are still unclear. Our aim was to validate the IGF-1-mediated mRNA/miRNA regulatory network in glioblastomas. Using in silico analyses of mRNA array and RNA sequencing data from The Cancer Genome Atlas (TCGA), we identified 32 core enrichment genes that were highly associated with IGF-1-promoted cytokine-cytokine receptor interactions. To investigate the IGF-1-downregulated miRNA signature, microarray-based approaches with IGF-1-treated U87-MG cells and array data in TCGA were used. Four miRNAs, including microRNA (miR)-9-5p, miR-9-3p, miR-181d, and miR-130b, exhibited an inverse correlation with IGF-1 levels. The miR-181d, that targeted the most IGF-1-related cytokine genes, was significantly reduced in IGF-1-treated glioma cells. Statistical models incorporating both high-IGF-1 and low-miR-181d statuses better predicted poor patient survival, and can be used as an independent prognostic factor in glioblastomas. The C-C chemokine receptor type 1 (CCR1) and interleukin (IL)-1b demonstrated inverse correlations with miR-181d levels and associations with patient survival. miR-181d significantly attenuated IGF-1-upregulated CCR1 and IL-1b gene expressions. These findings demonstrate a distinct role for IGF-1 signaling in glioma progression via miR-181d/cytokine networks.

Mutation of KRAS in non-small-cell lung cancer (NSCLC) shows a poor response to epidermal growth factor receptor (EGFR) inhibitors and chemotherapy. Currently, there are no direct anti-KRAS therapies available. Thus, new strategies have emerged for targeting KRAS downstream signaling. Panobinostat is a clinically available histone deacetylase inhibitor for treating myelomas and also shows potentiality in NSCLC. However, the therapeutic efficacy of panobinostat against gefitinib-resistant NSCLC is unclear. In this study, we demonstrated that panobinostat overcame resistance to gefitinib in KRAS-mutant/EGFR-wild-type NSCLC. Combined panobinostat and gefitinib synergistically reduced tumor growth in vitro and in vivo. Mechanistically, we identified that panobinostat-but not gefitinib-inhibited TAZ transcription, and the combination of panobinostat and gefitinib synergistically downregulated TAZ and TAZ downstream targets, including EGFR and EGFR ligand. Inhibition of TAZ by panobinostat or short hairpin RNA sensitized KRAS-mutant/EGFR-wild-type NSCLC to gefitinib through abrogating AKT/mammalian target of rapamycin (mTOR) signaling. Clinically, TAZ was positively correlated with EGFR signaling, and coexpression of TAZ/EGFR conferred a poorer prognosis in lung cancer patients. Our findings identify that targeting TAZ-mediated compensatory mechanism is a novel therapeutic approach to overcome gefitinib resistance in KRAS-mutant/EGFR-wild-type NSCLC.

MicroRNAs are small noncoding RNAs that post-transcriptionally control the expression of genes involved in glioblastoma multiforme (GBM) development. Although miR-302b functions as a tumor suppressor, its role in GBM is still unclear. Therefore, this study comprehensively explored the roles of miR-302b-mediated gene networks in GBM cell death. We found that miR-302b levels were significantly higher in primary astrocytes than in GBM cell lines. miR-302b overexpression dose dependently reduced U87-MG cell viability and induced apoptosis through caspase-3 activation and poly(ADP ribose) polymerase degradation. A transcriptome microarray revealed 150 downregulated genes and 380 upregulated genes in miR-302b-overexpressing cells. Nuclear factor IA (NFIA), higher levels of which were significantly related to poor survival, was identified as a direct target gene of miR-302b and was involved in miR-302b-induced glioma cell death. Higher NFIA levels were observed in GBM cell lines and human tumor sections compared with astrocytes and non-tumor tissues, respectively. NFIA knockdown significantly enhanced apoptosis. We found high levels of insulin-like growth factor-binding protein 2 (IGFBP2), another miR-302b-downregulated gene, in patients with poor survival. We verified that NFIA binds to the IGFBP2 promoter and transcriptionally enhances IGFBP2 expression levels. We identified that NFIA-mediated IGFBP2 signaling pathways are involved in miR-302b-induced glioma cell death. The identification of a regulatory loop whereby miR-302b inhibits NFIA, leading to a decrease in expression of IGFBP-2, may provide novel directions for developing therapies to target glioblastoma tumorigenesis.

The goal of this study was to explore the signaling pathway regulating the processing of proADAM17 into ADAM17 in Taiwan cobra phospholipase A 2 (PLA 2 )-treated human leukemia U937 cells. PLA 2 induced reactive oxygen species (ROS)-elicited p38 MAPK activation and ERK inactivation in U937 cells. Catalytically inactive bromophenacylated PLA 2 (BPB-PLA 2 ) and PLA 2 mutants evoked Ca 2+ -mediated p38 MAPK activation, and the level of phosphorylated ERK remained unchanged. PLA 2 treatment reduced mature ADAM17 expression and secreted TNF-α (sTNF-α) production. Co-treatment of SB202190 (p38 MAPK inhibitor) and catalytically inactive PLA 2 increased ERK phosphorylation, ADAM17 maturation and sTNF-α production. Nevertheless, mRNA levels of ADAM17 and TNF-α were insignificantly altered after PLA 2 and SB202190/BPB-PLA 2 treatment. ADAM17 activity assay and knock-down of ADAM17 revealed that ADAM17 was involved in sTNF-α production. Restoration of ERK activation increased the processing of proADAM17 into ADAM17 in PLA 2 -treated cells, while inactivation of ERK reduced ADAM17 maturation in untreated and SB202190/BPB-PLA 2 -treated cells. Removal of cell surface heparan sulfate abrogated PLA 2 and SB202190/BPB-PLA 2 effect on ADAM17 maturation. Taken together, the present data reveal that PLA 2 suppresses ERK-mediated ADAM17 maturation, thus reducing sTNF-α production in U937 cells. Moreover, the binding with heparan sulfate is crucial for the PLA 2 effect.

All-trans retinoic acid (ATRA), a derivative of retinoid, is involved in the onset of differentiation and apoptosis in a wide variety of normal and cancer cells. MicroRNAs (miRNAs) are small non-coding RNAs that control gene expression. Several miRNAs were identified to participate in ATRA-mediated cell differentiation. However, no studies have demonstrated whether miRNA can enhance ATRA cytotoxicity, thereby resulting in cell apoptosis. This study investigated the effects of ATRA-mediated miRNA expression in activating apoptotic pathways in glioblastoma. First, we found that high-dose ATRA treatment significantly reduced cell viability, caspase-dependent apoptosis, endoplasmic reticular (ER) stress activation, and intracellular reactive oxygen species accumulation. From microarray data, miR-302b was analyzed as a putative downstream regulator upon ATRA treatment. Furthermore, we found that ATRA up-regulated miR-302b expression in a dose- and time-dependent manner through retinoic acid receptor α-mediated pathway. Overexpression and knockdown of miR-302b significantly influenced ATRA-mediated cytotoxicity. E2F3, an important transcriptional regulator of glioma proliferation, was validated to be a direct target gene of miR-302b. The miR-302b-reduced E2F3 levels were also identified to be associated with ATRA-mediated glioma cell death. These results emphasize that an ATRA-mediated miR-302b network may provide novel therapeutic strategies for glioblastoma therapy. We propose that high-dose all-trans retinoic acid (ATRA) treatment, a derivative of retinoid, significantly induces glioblastoma cell apoptosis via caspase-dependent apoptosis, endoplasmic reticular (ER) stress, and intracellular reactive oxygen species (ROS) accumulation. The miR-302b overexpression enhanced by ATRA-mediated retinoic acid receptor (RAR)α pathway was also identified. The E2F3 repression, a novel target gene of miR-302b, was involved in ATRA-induced glioblastoma cell cytotoxicity.

Osteoporosis and periodontitis are both considered global health issues that threaten postmenopausal women and the older population. However, the correlation between osteoporosis and periodontitis is still unclear.Using a nationwide Taiwanese population-based database, data from patients with osteoporosis (2003 to 2005; n = 2,527) and 7,575 individuals who were matched to each patient by age and sex were analyzed. All participants were tracked for 5 years from the date of enrollment to observe the percentage of patients who developed periodontitis. Cox proportional hazard regressions were performed to evaluate 5-year periodontitis-free survival rates.Among the total sample, 3,060 individuals were diagnosed with periodontitis during the 5-year follow-up period: 792 in the study cohort and 2,268 in the comparison cohort. The adjusted hazard ratio for periodontitis in patients with osteoporosis compared with individuals without osteoporosis during the 5-year follow-up was 1.14 (95% confidence interval = 1.05 to 1.24, P0.01).This population-based study indicated that patients with osteoporosis may have an increased risk of periodontitis.

Antroquinonol (ANQ) is a ubiquinone derivative from the unique mushroom Antrodia camphorata, which exhibits broad-spectrum bioactivities. The effects of ANQ on cancer stem cell-like properties in colon cancer, however, remain unclear. In this study, we found that ANQ inhibited growth of colon cancer cells. The 50% growth inhibitions (GI50) of ANQ on HCT15 and LoVo were 34.8 ± 0.07 and 17.9 ± 0.07 μM. Moreover, ANQ exhibited inhibitory activities toward migration/invasion and tumorsphere formation of colon cancer cells. Mechanistically, ANQ inhibited pluripotent and cancer stem cell-related genes and down-regulated β-catenin/T-cell factor (TCF) signaling. Moreover, activation of the phosphatidylinositol-3-kinase (PI3K)/AKT/β-catenin signaling axis was identified to be crucial for regulating the expressions of pluripotent genes, whereas suppression of PI3K/AKT by ANQ inhibited expressions of β-catenin and downstream targets. Molecular docking identified the potential interaction of ANQ with PI3K. Our data s...

Temozolomide (TMZ), an alkylating agent of the imidazotetrazine series, is a first-line chemotherapeutic drug used in the clinical therapy of glioblastoma multiforme, the most common and high-grade primary glioma in adults. Micro (mi)RNAs, which are small noncoding RNAs, post-transcriptionally regulate gene expressions and are involved in gliomagenesis. However, no studies have reported relationships between TMZ and miRNA gene regulation. We investigated TMZ-mediated miRNA profiles and its molecular mechanisms underlying the induction of glioma cell death. By performing miRNA microarray and bioinformatics analyses, we observed that expression of 248 miRNAs was altered, including five significantly upregulated and 17 significantly downregulated miRNAs, in TMZ-treated U87MG cells. miR-128 expression levels were lower in different glioma cells and strongly associated with poor survival. TMZ treatment significantly upregulated miR-128 expression. TMZ significantly enhanced miR-128-1 promoter activity and transcriptionally regulated miR-128 levels through c-Jun N-terminal kinase 2/c-Jun pathways. The overexpression and knockdown of miR-128 expression significantly affected TMZ-mediated cell viability and apoptosis-related protein expression. Furthermore, the overexpression of miR-128 alone enhanced apoptotic death of glioma cells through caspase-3/9 activation, poly(ADP ribose) polymerase degradation, reactive oxygen species generation, mitochondrial membrane potential loss, and non-protective autophagy formation. Finally, we identified that key members in mammalian target of rapamycin (mTOR) signaling including mTOR, rapamycin-insensitive companion of mTOR, insulin-like growth factor 1, and PIK3R1, but not PDK1, were direct target genes of miR-128. TMZ inhibited mTOR signaling through miR-128 regulation. These results indicate that miR-128-inhibited mTOR signaling is involved in TMZ-mediated cytotoxicity. Our findings may provide a better understanding of cytotoxic mechanisms of TMZ involved in glioblastoma development.