Downregulation of miR-383 promotes glioma cell invasion by targeting insulin-like growth factor 1 receptor.

Invasiveness is a major clinical feature of glioma, an aggressive brain tumor with poor prognosis. Although there is emerging evidence that some microRNAs are involved in the glioma cell invasion process, it remains necessary to find functional microRNAs and elucidate the underlying molecular mechanisms. Here, we reported that a microRNA, miR-383, was downregulated in gliomas and inversely correlated with glioma pathological grades. Downregulation of miR-383 enhanced, whereas upregulation of miR-383 inhibited, the glioma cell invasive ability. Furthermore, we found that downregulation of miR-383 activated the AKT signaling following upregulation of MMP2 expression by directly targeting insulin-like growth factor 1 receptor (IGF1R). Importantly, we demonstrated that IGF1R expression is critical for miR-383 downregulation-induced cell invasion. Taken together, these findings uncover a novel regulatory mechanism for constitutive IGF1R signaling activation in glioma cancer and may provide miR-383 as a useful diagnostic marker or therapeutic target.

Human intravenous immunoglobulins suppress seizure activities and inhibit the activation of GFAP-positive astrocytes in the hippocampus of picrotoxin-kindled rats.

We previously showed that human intravenous immunoglobulin (IVIG) can lower seizure severity and prolong seizure latency in picrotoxin-kindled rats. The aim of this study was to further characterize the effects of IVIG on seizure activity and investigate its influence on astrocytes in the hippocampus of picrotoxin-kindled rats. A rat kindling model was established by peritoneal injections of picrotoxin for 21 days in Wistar rats. Seventy-five rats were equally divided into five groups: picrotoxin, IVIG pretreatment, IVIG post-treatment, normal saline control, and IVIG control. Seizure severity was evaluated according to a six-stage classification. The number and morphology of glial fibrillary acidic protein (GFAP)-positive astrocytes were studied by immunohistochemistry using the anti-GFAP antibody. The cross-sectional area and grayscale of GFAP-positive astrocytes were also determined. In picrotoxin-kindled rats, pretreatment with IVIG appeared to inhibit full kindling rates, and it significantly reduced the number of GFAP-positive cells in the hippocampus (p < .001). IVIG also significantly (p < .001) attenuated the increase in the cross-sectional area and grayscale of GFAP-positive astrocytes in the hippocampus. Our results suggest that by suppressing the expression of GFAP, IVIGs may reduce seizure activity and inhibit the activation of GFAP-positive astrocytes in picrotoxin-kindled rats.

[Expression of perforin in cord blood NK cells after IL-2/IL-15 stimulation and its relation with cytotoxicity].

This study was aimed to investigate the expression level of perforin in cord blood NK cells and the relation of perforin expression after IL-2, IL-15 stimulation to cytotoxicity of NK cells. NK cells were isolated from cord blood MNC by depleting CD3(+) cells and then enriching CD56(+) cells using immunomagnetic separation (CD3 and CD56 cell isolation kit, autoMACS, miltenyi). The purity was analysed by flow cytometry. According to the different combination of cytokines, there were two groups: group A (IL-2) and group B (IL-2 + IL-15). The cytotoxicity and perforin expression rate of fresh and different cultured CB-NK cells against K562/Jurkat cell lines were estimated by LDH release test (cytotoxic 96 non-radioactive cytotoxicity assay). The results showed that the purity of NK cells after separation was more than 90%. The cytotoxicity towards both tumor lines in group B was higher than that in group A (p < 0.05), and cytotoxicity in group A was higher than that of fresh NK cells (p < 0.05). Perforin expression rate of group A (84.55%) was higher than that of fresh NK cells (67.21%) (p < 0.05), and there was no significant difference between group A and B (84.55% versus 87.22%) Cytotoxic activity of CB-NK cells was positively correlated with perforin expression rate (r = 0.886, p < 0.05). It is concluded that IL-2 can enhance cytotoxicity of CB/BM-NK cells by increasing the perforin expression.

[Cytotoxic effect of IL-2/IL-15 stimulated cord blood derived NK cells on K562/Jurkat cell lines].

The aim of this study was to explore the cytotoxicity of fresh cord blood(CB) NK cells and the influence of IL-12 and IL-15 on activity of the NK cells killing K562 and Jurkat cells lines. The NK cells were isolated from cord blood by depleting CD3(+) cells and then enriching CD56(+) cells using sorting with immunomagnetic beads. The experiment was divided into 3 groups: group A (fresh CB-NK cells without cytokines), group B (CB-NK cells cultured by IL-2) and group C (CB-NK cells cultured by IL-2 and IL-15). The purity of NK cells was determined by flow cytometry; the cytotoxity of fresh and different cytokine-treated CB-NK cells on K562 and Jurkat cell lines was detected by LDH release test. The results showed that the purity of NK cells before and after sorting was 14.88 ± 9.2% and 92.39 ± 0.8% respectively. After culture for 3 days, NK-forming colony amounts in group B and group C were 148.60 ± 13.0 and 831.80 ± 23.0 respectively, the comparison between group B and group C showed the significant difference (p < 0.05). The cytotoxicities of NK cells in group A, B and C on K562 and Jurkat cell lines were 27.76 ± 8.8%, 61.90 ± 9.1% and 87.62 ± 3.7%; 29.32 ± 2.5%, 69.43 ± 4.4% and 92.95 ± 3.2% respectively, the difference was significant (p < 0.05). It is concluded that the fresh isolated CB-NK cells show low cytotoxic activity. After stimulated with IL-2 or IL-2 plus IL15, cytotoxicity of CB-NK cells increases obviously, the effect of IL-2 plus IL-15 is much better than IL-2 alone for promoting the growth and enhancing the cytotoxicity of CB-NK cells.

Effect of intravenous immunoglobulin treatment on brain interferon-gamma and interleukin-6 levels in a rat kindling model.

Many studies indicate that intravenous immunoglobulin (IgG) therapy may decrease symptoms of epilepsy. In this study, we assessed the effects of intravenous IgG in an experimental rat kindling model and attempted to elucidate the underlying mechanism of the IgG effect. For induction of kindling, Wistar rats received repeated intraperitoneal injections of picrotoxin. The serum level of neuron-specific enolase (NSE) was measured to determine seizure severity. Interferon (IFN)-gamma and interleukin (IL)-6 levels were measured in rat hippocampus homogenates. The serum NSE level and hippocampal IFN-gamma level were significantly higher in fully kindled, untreated rats compared to unkindled control rats, whereas IL-6 levels were similar in all groups. Intravenous IgG-treated kindled rats showed NSE and IFN-gamma levels similar to those of control rats, along with lower seizure severity and longer seizure latent period than fully kindled, untreated rats. These results indicate that intravenous immunoglobulin exerts a protective effect on the neurons of kindled rats, potentially by downregulating cytokines in the brain. These results shed light on the mechanism by which intravenous immunoglobulin decreases the severity of epileptic seizures.