Nestin small interfering RNA (siRNA) reduces cell growth in cultured astrocytoma cells

Optimized monoclonal antibody treatment against ELTD1 for GBM in a G55 xenograft mouse model

Glioblastoma is an aggressive brain tumour found in adults, and the therapeutic approaches available have not significantly increased patient survival. Recently, we discovered that ELTD1, an angiogenic biomarker, is highly expressed in human gliomas. Polyclonal anti-ELTD1 treatments were effective in glioma pre-clinical models, however, pAb binding is potentially promiscuous. Therefore, the aim of this study was to determine the effects of an optimized monoclonal anti-ELTD1 treatment in G55 xenograft glioma models. MRI was used to assess the effects of the treatments on animal survival, tumour volumes, perfusion rates and binding specificity. Immunohistochemistry and histology were conducted to confirm and characterize microvessel density and Notch1 levels, and to locate the molecular probes. RNA-sequencing was used to analyse the effects of the mAb treatment. Our monoclonal anti-ELTD1 treatment significantly increased animal survival, reduced tumour volumes, normalized the vasculature and showed higher binding specificity within the tumour compared with both control- and polyclonal-treated mice. Notch1 positivity staining and RNA-seq results suggested that ELTD1 has the ability to interact with and interrupt Notch1 signalling. Although little is known about ELTD1, particularly about its ligand and pathways, our data suggest that our monoclonal anti-ELTD1 antibody is a promising anti-angiogenic therapeutic in glioblastomas.

Liposomal delivery of ferritin heavy chain 1 (FTH1) siRNA in patient xenograft derived glioblastoma initiating cells suggests different sensitivities to radiation and distinct survival mechanisms

Elevated expression of the iron regulatory protein, ferritin heavy chain 1 (FTH1), is increasingly being associated with high tumor grade and poor survival outcomes in glioblastoma. Glioma initiating cells (GICs), a small population of stem-like cells implicated in therapeutic resistance and glioblastoma recurrence, have recently been shown to exhibit increased FTH1 expression. We previously demonstrated that FTH1 knockdown enhanced therapeutic sensitivity in an astrocytoma cell line. Therefore, in this study we developed a liposomal formulation to enable the in vitro delivery of FTH1 siRNA in patient xenograft derived GICs from glioblastomas with pro-neural and mesenchymal transcriptional signatures to interrogate the effect of FTH1 downregulation on their radiation sensitivity. Transfection with siRNA decreased FTH1 expression significantly in both GICs. However, there were inherent differences in transfectability between pro-neural and mesenchymal tumor derived GICs, leading us to modify siRNA: liposome ratios for comparable transfection. Moreover, loss of FTH1 expression resulted in increased extracellular lactate dehydrogenase activity, executioner caspase 3/7 induction, substantial mitochondrial damage, diminished mitochondrial mass and reduced cell viability. However, only GICs from pro-neural glioblastoma showed marked increase in radiosensitivity upon FTH1 downregulation demonstrated by decreased cell viability, impaired DNA repair and reduced colony formation subsequent to radiation. In addition, the stemness marker Nestin was downregulated upon FTH1 silencing only in GICs of pro-neural but not mesenchymal origin. Using liposomes as a siRNA delivery system, we established FTH1 as a critical factor for survival in both GIC subtypes as well as a regulator of radioresistance and stemness in pro-neural tumor derived GICs. Our study provides further evidence to support the role of FTH1 as a promising target in glioblastoma.

Nestin in immature embryonic neurons affects axon growth cone morphology and Semaphorin3a sensitivity

Correct wiring in the neocortex requires that responses to an individual guidance cue vary among neurons in the same location, and within the same neuron over time. Nestin is an atypical intermediate filament expressed strongly in neural progenitors and is thus used widely as a progenitor marker. Here we show a subpopulation of embryonic cortical neurons that transiently express nestin in their axons. Nestin expression is thus not restricted to neural progenitors, but persists for 2-3 d at lower levels in newborn neurons. We found that nestin-expressing neurons have smaller growth cones, suggesting that nestin affects cytoskeletal dynamics. Nestin, unlike other intermediate filament subtypes, regulates cdk5 kinase by binding the cdk5 activator p35. Cdk5 activity is induced by the repulsive guidance cue Semaphorin3a (Sema3a), leading to axonal growth cone collapse in vitro. Therefore, we tested whether nestin-expressing neurons showed altered responses to Sema3a. We find that nestin-expressing newborn neurons are more sensitive to Sema3a in a roscovitine-sensitive manner, whereas nestin knockdown results in lowered sensitivity to Sema3a. We propose that nestin functions in immature neurons to modulate cdk5 downstream of the Sema3a response. Thus, the transient expression of nestin could allow temporal and/or spatial modulation of a neuron's response to Sema3a, particularly during early axon guidance.

Suppression of Nestin reveals a critical role for p38-EGFR pathway in neural progenitor cell proliferation

The expression of intermediate filament Nestin is necessary for the neural progenitor cells (NPCs) to maintain stemness, but the underlying cellular and molecular mechanism remains unclear. In this study, we demonstrated that Nestin is required for the self-renew of NPCs through activating MAPK and EGFR pathways. Knockdown of Nestin by shRNA inhibited cell cycle progression and proliferation in mouse NPCs. Moreover, suppression of Nestin reduced expression of the epidermal growth factor receptor (EGFR) in NPCs and inhibited the mitogenic effects of EGF on these cells. Treatment of NPCs with p38-MAPK inhibitor PD169316 reversed cell cycle arrest caused by the knockdown of Nestin. Our findings indicate that Nestin promotes NPC proliferation via p38-MAPK and EGFR pathways, and reveals the necessity of these pathways in NPCs self-renewal.

Nestin-expressing vascular wall cells drive development of pulmonary hypertension

Nestin, a well-known marker of neuronal stem cells, was recently suggested to characterise stem cell-like progenitors in non-neuronal structures during development and tissue repair. Integrating novel morphological approaches (CLARITY), we investigate whether nestin expression defines the proliferating cell population that essentially drives vascular remodelling during development of pulmonary hypertension.The role of nestin was investigated in lungs of nestin-GFP (green fluorescent protein) mice, models of pulmonary hypertension (rat: monocrotaline, SU5416/hypoxia; mouse: hypoxia), samples from pulmonary hypertension patients and human pulmonary vascular smooth muscle cells (VSMCs).Nestin was solely found in lung vasculature and localised to proliferating VSMCs, but not bronchial smooth muscle cells. Nestin was shown to affect cell number and was significantly enhanced in lungs early during development of pulmonary hypertension, correlating well with increased VSMC proliferation, expression of phosphorylated (activated) platelet-derived growth factor receptor β and downregulation of the smooth muscle cell differentiation marker calponin. At later time points when pulmonary hypertension became clinically evident, nestin expression and proliferation returned to control levels. Increase of nestin-positive VSMCs was also found in human pulmonary hypertension, both in vessel media and neointima.Nestin expression seems to be obligatory for VSMC proliferation, and specifies lung vascular wall cells that drive remodelling and (re-)generation. Our data promise novel diagnostic tools and therapeutic targets for pulmonary hypertension.

Nestin overexpression promotes the embryonic development of heart and brain through the regulation of cell proliferation

Nestin, an intermediate filament protein, is a key regulator of various extracellular proteins that play important roles in cell growth and differentiation. In recent years, nestin has been widely accepted as a molecular marker for neural stem/progenitor cells. However, its function during embryogenesis remains largely unknown since its depletion is lethal after stage embryonic day 8.5 (E8.5). In order to understand the role of this protein in vivo, we compared the heart and brain tissues of control mice with those of mice overexpressing a human nestin cDNA transgene under the control of a ROSA26 promoter. In these tissues we examined the general histology and cell size, the presence of apoptotic cells by TUNEL assay, and the presence of progenitor cell markers like SOX2. Compared to controls, mouse embryos overexpressing the human nestin transgene have a larger size and display characteristic morphological changes including a larger heart and forebrain. In these tissues we found corresponding increases in the size of cardiomyocytes and brain cells, as well as indications of augmented cell proliferation. In contrast, apoptosis was not significantly altered. Co-staining brain sections with SOX2 and Ki67 showed that most of the proliferating cells in the forebrain were neural stem cells. Moreover, nestin overexpression was responsible for a marked activation of the PI3K/Akt signaling pathway. Taken together, the results of this study indicate that nestin plays an important role in the embryonic development of at least two mouse organs (heart and brain) through the regulation of cell proliferation.

Roles and potential clinical applications of intermediate filament proteins in brain tumors

Intermediate filament (IF) proteins are cytoplasmic and nuclear cytoskeletal proteins. Of the ~70 IF proteins, nearly 12 are found in the nervous system, where their expression is largely cell-type specific. Astrocytes express glial fibrillary acidic protein (GFAP), whereas different neuron types contain neurofilament proteins, α-internexin, or peripherin. These proteins are often downregulated in brain cancer. In addition, brain cancer cells may also contain vimentin, nestin, and synemin, which are the IF proteins found in neural progenitor cells. In different brain tumor types, the expression of nestin, vimentin, and α-internexin appears to correlate with the clinical outcome. Experimental investigations have also demonstrated that IF proteins have distinct roles in specific brain tumor cell behaviors: nestin, for instance, is important for the proliferation of glioma cells, whereas synemin also affect their mobility. The mechanisms responsible for these effects involve the interaction of IF proteins with specific signaling pathways. Synemin, for instance, positively regulates glioma cell proliferation by antagonizing protein phosphatase 2A. Further evidence for the potential of IF proteins as therapeutic targets derives from animal models showing the influence of IF proteins on tumor growth. Nestin downregulation, for instance, dramatically reduced intracerebral glioma growth. Selective targeted therapies of IFs to date primarily include gene therapy approaches using nestin or GFAP gene promoters to drive transgene expression into glioma cells. Although attempts to identify small molecules specifically antagonizing IF proteins have been unsuccessful to date, it is anticipated that the identification of such compounds will be instrumental in expanding therapeutic approaches for brain tumors.

Contribution of nestin positive esophageal squamous cancer cells on malignant proliferation, apoptosis, and poor prognosis

Background

The stem cell-associated intermediate filament nestin has recently been linked with neoplastic transformation, but the specific mechanism by which nestin positive tumor cells leads to malignant invasion and metastasis behaviors of esophageal squamous cell carcinoma (ESCC) remains unclear.

Methods

To obtain insight into the biological role of nestin in ESCC, we explored the association of the nestin phenotype with malignant proliferation and apoptosis in esophageal squamous cancer cells. Nestin expression was determined in ESCC specimens and cell lines, and correlated with clinicopathological properties, including clinical prognosis and proliferative markers. The association of the nestin phenotype with apoptotic indicators was also analyzed.

Results

Nestin was expressed in ESCC specimens and cell lines. ESCC patients with nestin-positive tumors had significantly shorter median survival and progression-free survival times than those with nestin-negative tumors. Positive staining for the proliferation markers Ki67 and PCNA (proliferating cell nuclear antigen) was detected in 56.9% and 60.2% of ESCC specimens, respectively, and was strongly correlated with the nestin phenotype. Notably, expression of cyclin dependent kinase-5 (CDK5) and P35 was detected in 53.8% and 48.4% of ESCC specimens, respectively, and was strongly associated with the nestin phenotype.

Conclusion

Our data demonstrated nestin expression in ESCC specimens and cell lines, and revealed a strong association of the nestin phenotype with poor prognosis in ESCC patients. Furthermore, we showed that nestin positive ESCC cells played an important role in the malignant proliferation and apoptosis.

High expression of the stem cell marker nestin is an adverse prognostic factor in WHO grade II-III astrocytomas and oligoastrocytomas

Infiltrating astrocytomas and oligoastrocytomas of low to anaplastic grade (WHO grades II and III), in spite of being associated with a wide range of clinical outcomes, can be difficult to subclassify and grade by the current histopathologic criteria. Unlike oligodendrogliomas and anaplastic oligodendrogliomas that can be identified by the 1p/19q codeletion and the more malignant glioblastomas (WHO grade IV astrocytomas) that can be diagnosed solely based on objective features on routine hematoxylin and eosin sections, no such objective criteria exist for the subclassification of grade II-III astrocytomas and oligoastrocytomas (A+OA II-III). In this study, we evaluated the prognostic and predictive value of the stem cell marker nestin in adult A+OA II-III (n = 50) using immunohistochemistry and computer-assisted analysis on tissue microarrays. In addition, the correlation between nestin mRNA level and total survival was analyzed in the NCI Rembrandt database. The results showed that high nestin expression is a strong adverse prognostic factor for total survival (p = 0.0004). The strength of the correlation was comparable to but independent of the isocitrate dehydrogenase 1/2 (IDH 1/2) mutation status. Histopathological grading and subclassification did not correlate significantly with outcome, although the interpretation of this finding is limited by the fact that grade III tumors were treated more aggressively than grade II tumors. These results suggest that nestin level and IDH 1/2 mutation status are strong prognostic features in A+OA II-III and possibly more helpful for treatment planning than routine histopathological variables such as oligodendroglial component (astrocytoma vs. oligoastrocytoma) and WHO grade (grade II vs. III).

Role of the stem cell-associated intermediate filament nestin in malignant proliferation of non-small cell lung cancer

Background

Nestin is associated with neoplastic transformation, but the mechanisms by which nestin contributes to invasion and malignancy of lung cancer remain unknown. Considering that proliferation is necessary for malignant behavior, we investigated the mechanism of nestin action in association with the proliferative properties of non-small cell lung cancer (NSCLC).

Methods

Nestin expression was examined in NSCLC specimens and cell lines. Associations with clinicopathological features, including prognosis and proliferative markers, were evaluated. Effects of nestin knockdown on proliferation and the signaling pathways involved were further investigated.

Results

Nestin was expressed in most cancer specimens and all the tumor cell lines analyzed. High nestin expression in malignant tissue was associated with high Ki-67 or PCNA levels and poor patient outcomes. Conversely, knockdown of nestin expression led to significant inhibition of tumor cell proliferation, decreased colony forming ability, and cell cycle G1 arrest. Furthermore, nestin knockdown resulted in inhibition of Akt and GSK3β activation.

Conclusions

Our data demonstrate that nestin expression in NSCLC cells is associated with poor prognosis of patients and tumor cell proliferation pathway. Downregulation of nestin efficiently inhibited lung cancer cell proliferation, which might be through affecting cell cycle arrest and Akt-GSK3β-Rb signaling pathway.

MiR-125b orchestrates cell proliferation, differentiation and migration in neural stem/progenitor cells by targeting Nestin

Background

The emerging concept is that microRNAs (miRNAs) play a central role in controlling stem cell self-renewal and fate determination by regulating the expression of stem cell regulators. miR-125b, one of neuronal miRNAs, recently was found to be necessary for neural differentiation of neural stem/progenitor cells (NS/PCs). However, the other specific biological role of miR-125b in NS/PCs is little known. We used rat NS/PCs as a model system to study the role of miR-125b in governing the behavior of NS/PCs.

Results

We report here the transfection of exogenous miR-125b inhibited proliferation of NS/PCs but promoted differentiation and migration. Whereas anti-miR-125b had the opposite effect. Similar results were observed when Nestin was knocked down by siRNA. Subsequently, we demonstrated that Nestin was a direct functional target of miR-125b. MiR-125b downregulates the expression of luciferase through Nestin 3’untranslated region (3’-UTR), and the regulation was abolished by mutations in the miR-125b binding site. MiR-125b targeted the 3'-UTR of Nestin and reduced the abundance of Nestin at both mRNA and protein levels.

Conclusion

The results provided new insight into the function by which miR-125b modulates NS/PCs proliferation, differentiation and migration. The data also indicated the regulatory role of miR-125b in NS/PCs might through the suppression of Nestin expression.

Nestin is required for the proper self-renewal of neural stem cells

The intermediate filament protein, nestin, is a widely employed marker of multipotent neural stem cells (NSCs). Recent in vitro studies have implicated nestin in a number of cellular processes, but there is no data yet on its in vivo function. Here, we report the construction and functional characterization of Nestin knockout mice. We found that these mice show embryonic lethality, with neuroepithelium of the developing neural tube exhibiting significantly fewer NSCs and much higher levels of apoptosis. Consistent with this in vivo observation, NSC cultures derived from knockout embryos show dramatically reduced self-renewal ability that is associated with elevated apoptosis but no overt defects in cell proliferation or differentiation. Unexpectedly, nestin deficiency has no detectable effect on the integrity of the cytoskeleton. Furthermore, the knockout of Vimentin, which abolishes nestin's ability to polymerize into intermediate filaments in NSCs, does not lead to any apoptotic phenotype. These data demonstrate that nestin is important for the proper survival and self-renewal of NSCs, and that this function is surprisingly uncoupled from nestin's structural involvement in the cytoskeleton.

Inducible expression of stem cell associated intermediate filament nestin reveals an important role in glioblastoma carcinogenesis

The intermediate filament nestin is transiently expressed in neural stem/progenitor cells during the development of central nervous system. Recently, increasing evidence has shown that upregulation of nestin is related to malignancy of several cancers, especially glioblastoma. However, the function of nestin in carcinogenesis remains unclear. In this study, we investigated the role of nestin in glioblastoma carcinogenesis by comparing subclones of rat C6 glioblastoma cells that were either high or low for nestin expression. We found that while nestin expression did not influence the in vitro proliferation of glioblastoma cells, subclones characterized by high levels of nestin formed tumors in vivo at significantly faster rates than subclones with low expression. Importantly, C6 subclones that expressed nestin at low levels in vitro were also found to give rise to tumors highly positive for the protein, suggesting that induction of nestin plays an important role in glioblastoma carcinogenesis. Derivation of nestin positive tumors from nestin negative human U87 glioblastoma cells in immunodeficient mice further confirmed that a switch to positive expression of nestin is fundamental to the course of glioblastoma development. Blocking the expression of nestin in glioblastoma tumors via intratumor injection of shRNA significantly slowed tumor growth and volume. These results demonstrated that nestin plays a crucial role in development of glioblastoma and may potentially be targeted for treatment of the disease.

Nestin is essential for mitogen-stimulated proliferation of neural progenitor cells

The intermediate filament (IF) protein nestin is a widely accepted molecular marker for neural progenitor cells (NPCs), but its function during neurogenesis remains largely unknown. We found that in embryonic cortical NPCs down-regulation of the expression of nestin, but not its co-polymer IF protein vimentin, resulted in a G1 cell-cycle arrest and a severe reduction in the generation of neurons. Furthermore, down-regulating nestin expression in cultured cortical NPCs markedly suppressed their colony-formation ability and blocked the elevation of the cyclin D1/E protein level in response to the treatment with bFGF. Interestingly, nestin down-regulation caused a marked suppression in the activation of the phosphoinositide 3-kinase (PI3K) pathway but not the mitogen-activated protein kinase (MAPK) pathway in these NPCs. Moreover, defects in the proliferation of cortical NPCs caused by nestin down-regulation could be prevented by up-regulating PI3K activity. Thus, nestin is essential for the proliferation of NPCs by promoting the activation of PI3K in response to mitogenic growth factors.

Predictive factors for overall and progression-free survival, and dissemination in oligodendroglial tumors

The pattern of recurrence and predictive factors for tumor progression, dissemination and survival in oligodendroglial tumors were investigated. 56 consecutive patients with oligodendroglial tumors were retrospectively analyzed to determine the predictive significance of various factors, including World Health Organization grade, loss of chromosomes 1p and 19q, and immunohistochemical features of TP53, O(6)-methylguanine-deoxyribonucleic-acid-methyltransferase, CD44H, nestin, and Ki-67. Eleven patients developed dissemination, and had significantly shorter post-progression survival compared to ten patients with local recurrence. Univariate analysis showed that retention of chromosome 1p or 19q, Ki-67 labeling index > or = 25%, diffuse expression of nestin, and p53 labeling index > or = 10% were unfavorable factors for overall, progression-free, and dissemination-free survival. Multivariate analysis showed that Ki-67 labeling index > or = 25% and diffuse expression of nestin were significant for dissemination-free survival. In conclusion, post-progression survival shows significant differences between patients with local and disseminated recurrence. Ki-67 labeling index and nestin expression pattern are useful markers to predict dissemination.