Zhenfeng Jiang

miR-656 Inhibits Glioma Tumorigenesis Through Repression of BMPR1A

Bone morphogenetic protein-2 (BMP-2), a member of the transforming growth factor-β family, plays critical roles in cell differentiation, modeling and regeneration processes in several tissues. BMP-2 is also closely associated with various malignant tumors. microRNAs negatively and posttranscriptionally regulate gene expression and function as oncogenes or tumor suppressors. Herein, we report that miR-656 expression was significantly downregulated in glioma cell lines and tissues. We identified and confirmed that BMP receptor, type 1A (BMPR1A) is a direct target of miR-656. The expression of BMPR1A was negatively correlated with that of miR-656 in human glioma tissues. We further demonstrated that miR-656 suppressed glioma cell proliferation, neurosphere formation, migration and invasion with or without exogenous BMP-2. Engineered knockdown of BMPR1A diminished the antiproliferation effect of miR-656 in vitro. Moreover, the canonical BMP/Smad and non-canonical BMP/mitogen-activated protein kinase (MAPK) pathways were inhibited by miR-656 overexpression. Several cancer-related signaling molecules, including cyclin B, cyclin D1, matrix metalloproteinase-9, p21 and p27, were also involved in miR-656 function in glioma cells. The tumor-suppressing function of miR-656 was validated using an in vivo intracranial xenograft mouse model. Notably, ectopic expression of miR-656 markedly reduced tumor size and prolonged the survival of mice treated with or without BMP-2. These results elucidate the function of miR-656 in glioma progression and suggest a promising application for glioma treatment.

Protection against cognitive impairment and modification of epileptogenesis with curcumin in a post-status epilepticus model of temporal lobe epilepsy

Epileptogenesis is a dynamic process initiated by insults to the brain that is characterized by progressive functional and structural alterations in certain cerebral regions, leading to the appearance of spontaneous recurrent seizures. Within the duration of the trauma to the brain and the appearance of spontaneous recurrent seizures, there is typically a latent period, which may offer a therapeutic window for preventing the emergence of epilepsy. Previous animal studies have shown that curcumin can attenuate acute seizure severity and brain oxidative stress, but the effect of curcumin on epileptogenesis has not been studied. We examined the effect of continued administration of curcumin during the latent period on epileptogenesis and the deleterious consequences of status epilepticus in adult rats in a post-status epilepticus model of temporal lobe epilepsy induced by kainic acid. We demonstrate that, while administration of curcumin treatment during the latent period does not prevent occurrence of spontaneous recurrent seizures after status epilepticus, it can attenuate the severity of spontaneous recurrent seizures and protect against cognitive impairment. Thus, treatment with curcumin during the latent period following status epilepticus is beneficial in modifying epileptogenesis.

Centrosomal Protein of 55 Regulates Glucose Metabolism, Proliferation and Apoptosis of Glioma Cells via the Akt/mTOR Signaling Pathway.

Introduction: Glioma is one of the most common and most aggressive brain tumors in humans. The molecular and cellular mechanisms responsible for the onset and the progression of glioma are elusive and controversial. Centrosomal protein of 55 (CEP55) was initially described as a highly coiled-coil protein that plays critical roles in cell division, but was recently identified as being overexpressed in many human cancers. The function of CEP55 has not previously been characterized in glioma. We aim to discover the effect and mechanism of CEP55 in glioma development. Method: qRT-PCR and immunohistochemistry were used to analyze CEP55 expression. Glucose uptake, western blot, MTS, CCK-8, Caspase-3 activity and TUNEL staining assays were performed to investigate the role and mechanism of CEP55 on glioma cell process. Results: We found that the levels of CEP55 expression were upregulated in glioma. In addition, CEP55 appeared to regulate glucose metabolism of glioma cells. Furthermore, knockdown of CEP55 inhibited cell proliferation and induced cell apoptosis in glioma. Finally, we provided preliminary evidence that knockdown of CEP55 inhibited glioma development via suppressing the activity of Akt/mTOR signaling. Conclusions: Our results demonstrated that CEP55 regulates glucose metabolism, proliferation and apoptosis of glioma cells via the Akt/mTOR signaling pathway, and its promotive effect on glioma tumorigenesis can be a potential target for glioma therapy in the future.

miR-422a Inhibits Glioma Proliferation and Invasion by Targeting IGF1 and IGF1R

Glioma is a common type of malignant brain tumor characterized by aggressive metastasis capability. Recent evidence has suggested that noncoding RNAs, including microRNAs, have important functions in the pathophysiology of glioma development. In this study, we investigated the biological function of miR-422a in human glioma. We found that miR-422a was downregulated in glioma tissues. We also demonstrated that expression of miR-422a in glioma cells markedly suppressed cell proliferation, migration, and invasion. In addition, we identified insulin-like growth factor 1 (IGF1) and IGF1 receptor (IGF1R) as inhibitory targets of miR-422a in glioma cells. We established that the expression levels of miR-422a were negatively correlated with the expression levels of IGF1/IGF1R and the clinical parameters in glioma patients. An IGFR inhibitor, AG1024, completely blocked the activity of miR-442a on glioma cell proliferation and invasion, which further confirmed that miR-422a functions through IGF1 and IGF1R.

TUSC3 suppresses glioblastoma development by inhibiting Akt signaling

Glioblastoma multiform is one of the most common and most aggressive brain tumors in humans. The molecular and cellular mechanisms responsible for the onset and progression of GBM are elusive and controversial. The function of tumor suppressor candidate 3 (TUSC3) has not been previously characterized in GBM. TUSC3 was originally identified as part of an enzyme complex involved in N-glycosylation of proteins, but was recently implicated as a potential tumor suppressor gene in a variety of cancer types. In this study, we demonstrated that the expression levels of TUSC3 were downregulated in both GBM tissues and cells, and also found that overexpression of TUSC3 inhibits GBM cell proliferation and invasion. In addition, the effects of increased levels of methylation on the TUSC3 promoter were responsible for decreased expression of TUSC3 in GBM. Finally, we determined that TUSC3 regulates proliferation and invasion of GBM cells by inhibiting the activity of the Akt signaling pathway.

Glutamine promotes Hsp70 and inhibits α-Synuclein accumulation in pheochromocytoma PC12 cells

Hsp70 regulates α-Synuclein (α-Syn) degeneration in Parkinsons disease (PD), indicating that Hsp70 promotion may be able to prevent or reverse α-Syn-induced toxicity in PD. Additionally, it has been demonstrated that glutamine (Gln) enhances Hsp70 expression. In the present study, Gln-induced Hsp70 promotion in pheochromocytoma was investigated with reverse transcription- quantitative polymerase chain reaction and western blotting methods. Then it was observed whether heat shock factor (HSF)-1 was required for this phenomenon with an RNA interference strategy. The regulatory role of Gln on α-Syn degeneration was also determined in the α-Syn-overexpressed PC12 [PC12 (α-Syn+)] cells, which were treated with or without the proteasomal inhibitor lactacystin (Lac). The results demonstrated that treatment with ≥10 mM Gln significantly increased Hsp70 mRNA and protein levels (P<0.05) and that this promotion was HSF-1-dependent, as HSF-1 knockout with HSF-1-specific small interfering RNA abrogated Hsp70 promotion in PC12 (α-Syn+) cells. Furthermore, Gln treatment markedly upregulated α-Syn degeneration in PC12 (α-Syn+) cells, which was significantly reduced (P<0.05) in the presence of Lac. Therefore, the present study suggests that Gln is able to induce the promotion of Hsp70 expression in PC12 cells in an HSF-1-dependent manner and that Gln-mediated Hsp70 promotion may increase α-Syn degradation even in the presence of proteasomal inhibitor. Thus, glutamine may be a potential therapeutic agent to prevent α-Syn aggregation in PD.

Targeting of microRNA-21-5p protects against seizure damage in a kainic acid-induced status epilepticus model via PTEN-mTOR

OBJECTIVE Studies have shown that microRNAs play a role in the development of epilepsy by regulating downstream target messenger (m)RNA. The present study aims to determine the changes associated with microRNA-21-5p (miR-21-5p) during epileptogenesis in a kainic acid rat model, and to assess whether the PTEN-mTOR pathway is a target of miR-21-5p. METHOD Reverse transcription polymerase chain reaction (RT-PCR) was used to examine the quantitative expressions of miR-21-5p and PTEN, and Western blotting was used to test the activity of mTOR in the acute, latent, and chronic stages of epileptogenesis. The antagomir of miR-21-5p was injected into the intracerebroventricular space using a microsyringe. Neuronal death and epilepsy discharge were assessed by Nissl staining and electroencephalography (EEG), respectively. The Morris water maze (MWM) was used to assess the cognitive impairment in rats after status epilepticus (SE). RESULTS Both miR-21-5p and mTOR were upregulated and PTEN was downregulated in rats during acute, latent, and chronic stages of epileptogenesis when compared with those of the control. After using antagomir miR-21-5p in vivo, miR-21-5p and mTOR decreased and the expression of PTEN increased compared with that in the SE model. The silencing of miR-21-5p diminished the number of abnormal spikes on EEG and decreased the number of neuron deletions on Nissl staining. The cognitive and memory impairment caused by epilepsy could also be improved after miR-21-5p knockdown in vivo. CONCLUSION The results of the present study demonstrate that PTEN-mTOR is the target of miR-21-5p in a kainic acid model of epilepsy. The knockout of miR-21-5p decreases the neuronal damage in stages of epileptogenesis. The miR-21-5p/PTEN/mTOR axis may be a potential target for preventing and treating seizures and epileptic damage.

miRNA-214 inhibits cellular proliferation and migration in glioma cells targeting caspase-1 involved in pyroptosis.

Pyroptosis is a type of proinflammatory programmed cell death mediated by caspase 1 activity and occurs in several types of eukaryotic tumor cells, including gliomas. MicroRNAs (miRNAs), small endogenous noncoding RNAs, have been demonstrated to be advantageous in glioma therapy. However, the question of whether miRNAs regulate pyroptosis in glioma remains unknown. The current study found that caspase 1 expression was substantially increased in both glioma tissues and glioma cell lines, U87 and T98G, while miR-214 expression was significantly downregulated. Luciferase reporter assay recognized caspase 1 as a target gene of miR-214. These findings demonstrate that miR-214 could inhibit cell proliferation and migration through the regulation of pyroptosis intermediated by caspase 1 in glioma U87 and T98G cells and may suggest a novel therapeutic for the intervention of glioma.

PARK2 negatively regulates the metastasis and epithelial‑mesenchymal transition of glioblastoma cells via ZEB1

Glioblastoma multiforme (GBM), one of the most aggressive human malignant brain tumors, is induced by multiple complex pathological mechanisms. The main cause of mortality in patients with GBM is the invasion-metastasis cascade of tumor cells. The dysfunction of Parkinson protein 2 E3 ubiquitin protein ligase (PARK2) is closely linked with the development of certain human cancers. However, whether PARK2 is associated with metastasis in GBM remains unknown. The present study demonstrated that the metastasis and invasion of U87 cells were significantly repressed by PARK2 overexpression. Conversely, knockdown of PARK2 facilitated the metastasis and invasion of A172 cells. Furthermore, PARK2 downregulated zinc finger E-box-binding homeobox 1 (ZEB1) expression and mitigated epithelial-mesenchymal transition (EMT). Promoter effects of PARK2 knockdown on cell metastasis and EMT were antagonized by silencing ZEB1 expression. These results indicated that PARK2 participated in regulating the invasion-metastasis cascade of cancer cells by depressing ZEB1 expression and acting as a metastasis suppressor in GBM progression, providing a potential therapeutic approach for GBM treatment.