Lactate-induced up-regulation of PLEKHA4 promotes proliferation and apoptosis of human glioma cells / 南方医科大学学报

OBJECTIVE@#To investigate the effect of lactic acid-induced upregulation of PLEKHA4 expression on biological behaviors of glioma cells and the possible molecular mechanism.@*METHODS@#GEO database and GEPIA2 website were used to analyze the relationship between PLEKHA4 expression level and the pathological grade of glioma. A specific PLEKHA4 siRNA was transfected in glioma U251 and T98G cells, and the changes in cell proliferation ability were assessed by real-time cell analysis technology and Edu experiment. The colony-forming ability of the cells was evaluated using plate cloning assay, and cell cycle changes and cell apoptosis were analyzed with flow cytometry. The mRNA expression of PLEKHA4 was detected by PCR in glioma samples and controls and in glioma cells treated with lactic acid and glucose. Xenograft mice in vivo was used to detect tumor formation in nude mice; Western blotting was used to detect the expressions of cyclinD1, CDK2, Bcl2, β-catenin and phosphorylation of the key proteins in the MAPK signaling pathway.@*RESULTS@#The results of GEO database and online website analysis showed that PLEKHA4 was highly expressed in glioma tissues and was associated with poor prognosis; PLEKHA4 knockdown obviously inhibited the proliferation and attenuated the clone-forming ability of the glioma cells (P < 0.05). Flow cytometry showed that PLEKHA4 knockdown caused cell cycle arrest in G1 phase and promoted apoptosis of the cells (P < 0.01). PLEKHA4 gene mRNA expression was increased in glioma samples and glioma cells after lactate and glucose treatment (P < 0.01). PLEKHA4 knockdown, tumor formation ability of nude mice decreased; PLEKHA4 knockdown obviously lowered the expression of cyclinD1, CDK2, Bcl2 and other functional proteins, inhibited the phosphorylation of ERK and p38 and reduced the expression of β-catenin protein (P < 0.01).@*CONCLUSION@#PLEKHA4 knockdown inhibited the proliferation of glioma cells and promoted apoptosis by inhibiting the activation of the MAPK signaling pathway and expression of β-catenin. Lactic acid produced by glycolysis upregulates the expression of PLEKHA4 in glioma cells.

Piroctone olamine disrupts mitochondrial dynamics in glioma cells through the PI3K/AKT pathway / 南方医科大学学报

OBJECTIVE@#To investigate the growth-inhibitory and pro-apoptotic effects of piroctone olamine (PO) on glioma cells and explore the underlying mechanism.@*METHODS@#Human glioma cell lines U251 and U373 were treated with PO and the changes in cell proliferation were detected using CCK-8 assay and EdU assay. Clone formation assay and flow cytometry were used to examine the changes in clone formation ability and apoptosis of the treated cells. Mitochondrial membrane potential of the cells and morphological changes of the mitochondria were detected using JC-1 staining and a fluorescence probe, respectively. The expressions of mitochondrial fission protein DRP1 and the fusion protein OPA1 were determined with Western blotting. Transcriptome sequencing and differential gene enrichment analysis was performed, and the expression levels of PI3K, AKT and p-AKT in the treated cells were verified using Western blotting.@*RESULTS@#CCK-8 assay showed that PO significantly inhibited the proliferation of U251 and U373 cells in a time- and dose-dependent manner (P < 0.001). EdU test showed that the proliferative activity of PO-treated cells was significantly decreased, and the number of cell colonies also decreased significantly (P < 0.01). PO treatment significantly increased apoptotic rates (P < 0.01), decreased mitochondrial membrane potential and caused obvious changes in mitochondrial morphology of the cells. Pathway enrichment analysis showed that the down-regulated genes were significantly enriched in the PI3K/AKT pathway, which was verified by Western blotting showing significantly down-regulated expression levels of PI3K, AKT and p-AKT in PO-treated cells (P < 0.05).@*CONCLUSION@#PO interferes with mitochondrial fusion and fission function through the PI3K/AKT pathway, thereby inhibiting the proliferation and increasing apoptosis of glioma cells.

Detection of Cd in Chinese Cabbage by Laser Induced Breakdown Spectroscopy Coupled with Multivariable Selection / 分析化学

Heavy metal residue in vegetables is a big concern in the whole world.The aim of this work is to explore the effect of multivariable selection on analyzing Cd in Chinese cabbage polluted in lab by collecting the spectra of laser induced breakdown spectroscopy (LIBS) from the samples.At the same time,the actual Cd content in samples was obtained by anodic stripping voltammetry (ASV).The LIBS spectral range in partial least square (PLS) model was screened by standard normal variable transformation (SNV),first derivative (FD),second derivative (SD) and center treatment (CT) for preprocessing spectra and the optimized method was used for the analysis of interval partial least square (iPLS) and synergy interval partial least square (SiPLS).The results indicated that the method of CT was the best as a comparison with PLS,iPLS and SiPLS.And the intervals of wavelength were 214.72-215.82 nm,215.88-216.97 nm and 225.08 -226.35 nm by utilizing the optimized SiPLS.Here the root mean square error of cross validation (RMSECV) between real content and predicted ones was 1.487,the root mean squared error of prediction (RMSEP) was 1.094,the correlation coefficient (R) was 0.9942,and the average relative error (ARE) was 11.60％.The results displayed that LIBS could predict Cd in vegetables by multivariable selection of SiPLS and the accuracy could meet the requirement of rapid and green analysis of Cd in vegetables.

Spectral Filtering Method for Improvement of Detection Accuracy of Lead in Vegetables by Laser Induced Breakdown Spectroscopy / 分析化学

There are many noise signals in original laser induced breakdown spectroscopy (LIBS) spectra.To explore the effect of spectral pretreatment on LIBS information by different filter methods, the LIBS spectra of Pb-polluted cabbage in wavelength range of 400.45-410.98 nm was investigated and preprocessed by adjacent averaging, Savitzky-Golay (S-G) and fast Fourier transformation (FFT).Then partial least square (PLS) model was established for evaluating the spectral treatment effect.The result showed that the root mean square error of prediction (RMSEP) and average relative error of S-G method were 0.26 and 3.7%, suggesting a superior smoothing effect than other methods.Experimental results indicated that an appropriate filtering method could help to improve the spectral quality and raise the precision of model checkout.