Cx32 promotes autophagy and produces resistance to SN­induced apoptosis via activation of AMPK signalling in cervical cancer.

The roles of gap junctions (GJs) and its components, connexins, in the autophagy of cervical cancer cells have been rarely investigated. Our previous study demonstrated that connexin 32 (Cx32) exerted an anti­apoptotic effect on cervical cancer. However, as an important regulator of apoptosis, whether the autophagy is involved in the function of Cx32 on cervical cancer cells is not well defined. The present study aimed to investigate the role of Cx32 on autophagy and apoptosis inhibition in cervical cancer cells. The expression levels of Cx32 and the autophagy­associated protein LC3­â…¡ in paracancerous cervical tissues (n=30) and cervical cancer (n=50) tissues were determined via western blotting. In total, 45 cervical cancer specimens were used to evaluate the clinical relevance of Cx32 and LC3­â…¡. It was found that both Cx32 and LC3­â…¡ were upregulated in cervical cancer tissues compared with those in paracancerous cervical tissues. The effect of Cx32 on autophagy was examined by detecting the change of LC3­â…¡ using western blotting, transfection with enhanced green fluorescent protein­LC3 plasmid and transmission electron microscopy analysis. Overexpression of Cx32 significantly enhanced autophagy in HeLa­Cx32 cells, whereas knockdown of Cx32 suppressed autophagy in C­33A cells. The flow cytometry results demonstrated that Cx32 inhibited the apoptosis of cervical cancer cells by promoting autophagy. Moreover, Cx32 triggered autophagy via the activation of the AMP­activated protein kinase (AMPK) signalling, regardless of the presence or absence of GJs. Collectively, it was identified that Cx32 exerted its anti­apoptotic effect by activating autophagy via the AMPK pathway in cervical cancer, which demonstrates a novel mechanism for Cx32 in human cervical cancer progression.

The association of plasma lipids with white blood cell counts: Results from the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Previous studies have demonstrated that elevated cholesterol results in increased white blood cell counts in mouse models. However, there is insufficient evidence to support this in humans. OBJECTIVE: The objective of the study was to investigate the relationship of plasma lipids with white blood cell counts (basophils, eosinophils, monocytes, neutrophils and lymphocytes) in the Multi-Ethnic Study of Atherosclerosis. METHODS: The analysis included 2873 Multi-Ethnic Study of Atherosclerosis participants with a complete white blood count and differential analysis. The cross-sectional association of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride levels with different white blood cell counts was analyzed by multivariable linear regression. RESULTS: After adjusting for sociodemographic and confounding factors including red blood cell counts, platelet counts, use of lipid-lowering medication, cardiovascular disease risk factors and other lipid measures, and multiple testing correction, a one-standard deviation increment in total cholesterol and low-density lipoprotein cholesterol was associated with 2.8% and 2.3% lower total white blood cell counts, 3.7% and 3.0% lower monocyte counts, and 3.4% and 2.7% lower neutrophil counts (all P < .01). The same increment in logarithm-transformed triglyceride levels was associated with 2.3% higher total white blood cell counts and 4.5% higher lymphocyte counts (both P < .001). Similar results were obtained after excluding participants taking lipid-lowering medication. A one-standard deviation increase in high-density lipoprotein cholesterol was associated with a 1.5% lower white blood cell count (P = .018) but was not significantly associated with changes in any individual cell type. CONCLUSION: While significant associations were observed between plasma lipid levels and white blood cell populations, the heterogeneous and modest nature of these relationships makes it hard to support the hypothesis that lipids are in the causal pathway for leukogenesis in humans.

Non-junctional Cx32 mediates anti-apoptotic and pro-tumor effects via epidermal growth factor receptor in human cervical cancer cells / 中国药理学与毒理学杂志

ABSTRACT:OBJECTIVE To investigate the role of connexin proteins (Cx), which form gap junctions (GJ), in progression and chemotherapeutic sensitivity of cervical cancer (CaCx). METHODS We analyze the expression of Cx26, Cx30, Cx32 and Cx43 in human specimens consisting of: Normal cervix (n=78), CaCx FIGO stage Ⅰ (n=148), CaCx FIGO stage Ⅱ (n=165). InCaCx cell lines, Hela- Cx32 (induced expression by doxycycline), C- 33A (endogenously express Cx32) and siHa (transiently transfected plasmid with Cx32), we detected the role of Cx32 against tostreptonigrin/cisplatin-induced apopotosisin presence or absence of functional GJ through using GJ inhibitors or low density cultural.Furtherly, we observed the relativity of Cx32 and EGFR expression in human specimens. Also, we detected the role of EGFR signaling pathway in the process of Cx32 anti-apoptosis through suppressed EGFR expression by inhibitors or siRNA sequences in cell lines. RESULTS We firstly demonstrated the expression of Cx32 was highly upregulated and accumulated in cytoplasm in the CaCx specimens, and the degree of upregulation correlated with advanced FIGO stages. Thus,in three human cervical cell lines, Cx32 was shown to suppress apoptosis when GJ formation is inhibited. No matter in cases of CaCx or cell lines, Cx32 expression was highly correlated with expression of EGFR and the EGFR pathway is an essential component of the Cx32-induced anti-apoptotic effect. CONCLUSION Cx32, traditionally tumor suppressive protein, was shown to be tumor protective against chemotherapy through EGFR pathway in a GJ-independent way.

[Protective effect of rutin against oxidative injury in neuronal cells].

OBJECTIVE: To observe the protective effect of rutin (RUT) on neuronal cells against sodium nitroprusside (SNP) induced neurotoxicity. METHODS: PC12 cells were treated with different concentration of SNP for 24 h and MTT assay was applied to analyze the survival rate; PC12 cells were pretreated with rutin for 1 h, and then incubated for 24 h with SNP. MTT assay, morphological observation, as well as immunofluorescence were performed to evaluate both the SNP neurotoxicity and the protective effects of RUT, Western blot was used to analyzed the level of phosphorylated extra cellular regulated protein kinases (ERK1/2) after treatment with RUT, the results were also testified in primary cultured neurons. RESULTS: Results from MTT assay showed that SNP caused cell death in a concentration-dependent manner in PC12 cells. The effect of SNP was observed at 200 - 1 000 micromol/L and was significant at 800 micromol/L. 25 micromol/L rutin partly blocked the neurotoxicity of SNP by preventing PC12 cells from apoptosis. Hoechst and PI staining indicated that SNP treatment decreased the number of viable cells and induced shrinkage and aggregation of the nucleus, whereas RUT pretreatment attenuated the toxic effects of SNP, after treatment with RUT in PC12 cells, the phosphorylation of ERK1/2 was increased and peaked at 20 min. Most importantly, the protective effect of RUT on PC12 cells was confirmed on cultured neurons. CONCLUSION: RUT possesses protective effect against neuronal apoptosis induced by SNP and this effect may be partially related with ERK1/2 signaling.

[Neurotrophic effects of protocatechuic acid on neurite outgrowth and survival in cultured cerebral cortical neurons of newborn rat].

OBJECTIVE: To study the neurotrophic effects of protocatechuic acid on neurite outgrowth and survival in cultured cerebral cortical neurons. METHODS: The newborn rat cerebral cortex neurons were cultured in vitro. The convert phase microscope was used to count the survival neurons with neurites and measure the average length of neurites. MTT and LDH assay were carried out to investigate the effect of PCA on the neuronal viability. RESULTS: Compared with control group, different concentration of PCA could increase the number of survival neurons with neurites and the average length of neurites. MTT and LDH assay showed that PCA promoted neuron survival in a dose-dependent manner. CONCLUSION: PCA can enhance the survival of rat cortical neurons with neurites and promote the neurite outgrowth of rat cortical neurons.

[Effects of ferulic acid on bFGF-treated PC12 cells].

OBJECTIVE: To explore the effect and mechanism of ferulic acid on differentiation in bFGF-treated PC12 cells. METHODS: The length of neurite outgrowth and the percentage of PC12 cells induced in the presence of 0 ng/mL or 1 ng/mL bFGF were assayed. RESULTS: Compared with that of control group,ferulic acid could enhance the differentiation effect of bFGF (1 ng/mL) in PC12 cells (P < 0.01) and the enhancing effect could be blocked by the specific MAPK kinase inhibitor, PD98059. CONCLUSION: Ferulic acid potentiates neurite outgrowth in bFGF-treated PC12 cells by MAPK-dependent signaling pathway.