Uncovering the ceRNA network and DNA methylation associated with gene expression in nasopharyngeal carcinoma

OBJECTIVE

This study aimed to uncover abnormally expressed genes regulated by competitive endogenous RNA (ceRNA) and DNA methylation nasopharyngeal carcinoma and to validate the role of lncRNAs in the ceRNA network on nasopharyngeal carcinoma progression.

METHODS

Based on the GSE64634 (mRNA), GSE32960 (miRNA), GSE95166 (lncRNA), and GSE126683 (lncRNA) datasets, we screened differentially expressed mRNAs, miRNAs and lncRNAs in nasopharyngeal carcinoma. A ceRNA network was subsequently constructed. Differentially methylated genes were screened using the GSE62336 dataset. The abnormally expressed genes regulated by both the ceRNA network and DNA methylation were identified. In the ceRNA network, the expression of RP11-545G3.1 lncRNA was validated in nasopharyngeal carcinoma tissues and cells by RT-qPCR. After a knockdown of RP11-545G3.1, the viability, migration, and invasion of CNE-2 and NP69 cells was assessed by CCK-8, wound healing and Transwell assays.

RESULTS

This study identified abnormally expressed mRNAs, miRNAs and lncRNAs in nasopharyngeal carcinoma tissues. A ceRNA network was constructed, which contained three lncRNAs, 15 miRNAs and 129 mRNAs. Among the nodes in the PPI network based on the mRNAs in the ceRNA network, HMGA1 was assessed in relation to the overall and disease-free survival of nasopharyngeal carcinoma. We screened two up-regulated genes regulated by the ceRNA network and hypomethylation and 26 down-regulated genes regulated by the ceRNA network and hypermethylation. RP11-545G3.1 was highly expressed in the nasopharyngeal carcinoma tissues and cells. Moreover, the knockdown of RP11-545G3.1 reduced the viability, migration, and invasion of CNE-2 and NP69 cells.

CONCLUSION

Our findings uncovered the epigenetic regulation in nasopharyngeal carcinoma and identified the implications of RP11-545G3.1 on the progression of nasopharyngeal carcinoma.

Toxicity of the Mycotoxin Deoxynivalenol on Early Cleavage of Mouse Embryos by Fluorescence Intensity Analysis

Deoxynivalenol is a mycotoxin, produced by Fusarium from contaminated corn, wheat, and other grains, that induces multiple effects in humans and animals, including cytotoxic, genotoxic, immunotoxic, and carcinogenic effects. Recent studies show that deoxynivalenol also affects the reproductive system of mammals, including oocyte quality. However, the effects of deoxynivalenol on early embryonic development have not been reported. In this study, fluorescence intensity analysis was used to show that deoxynivalenol disrupted the first cleavage of the zygote. The high deoxynivalenol dose disturbed the movement of the pronucleus after fertilization, while the low deoxynivalenol dose caused aberrant spindle morphology during the metaphase of the first cleavage. Further analysis showed that the reactive oxygen species level increased in the deoxynivalenol-exposed two-cell embryos, indicating oxidative stress. Moreover, deoxynivalenol caused DNA damage in the embryos, as positive γH2A.X signals were detected in the nucleus. These events led to the early apoptosis of mouse embryos, which was confirmed by autophagy. Taken together, our study provides evidence for the toxicity of deoxynivalenol during early embryonic development in the mouse model.

Exposure to nonylphenol impairs oocyte quality via the induction of organelle defects in mice

Nonylphenol (NP) is an environmental endocrine disruptor, which is mainly used in the production of surfactants, lubricants, additives, pesticides, and emulsifiers. NP is widely found in sewage and sludge, which has neurotoxicity, immunotoxicity, metabolic toxicity and reproductive toxicity. In this study, we investigated the effects of NP exposure on mammalian oocyte quality from organelle aspects with mouse in vivo model. The results showed that the ovarian weight of mice exposed to 500 μg/L NP for 4 weeks increased and the development ability of oocytes decreased, showing with lower rate of polar body extrusion. Further analysis indicated that exposure to NP caused the abnormal distribution of mitochondria, following with altered membrane potential drop. NP exposure disrupted the spindle periphery localization of ER, and affected the expression of GRP78 for the induction of ER stress. Moreover, Golgi apparatus fragment in the oocytes was observed, and Rab11-based vesicle transport was disturbed. We also found that the protein degradation might be affected since LAMP2 expression increased and LC3 decreased, indicating the lysosome and autophagy dysfunction. Taken together, our findings suggested that the exposure of NP to mice in vivo affected oocyte quality through its effects on the distribution and function of organelles.

[Correlation of single nucleotide polymorphisms of the osteopontin gene with astheozoospermia]

OBJECTIVE

To investigate the correlation of the single nucleotide polymorphisms (SNP) rs1126772, rs117291487, rs11730582, rs142608941 and rs6813526 of the osteopontin (OPN) gene with the risk of asthenozoospermia (AZS).

METHODS

We included 135 AZS patients in the AZS group and another 239 fertile men as normal controls. Using the SNaPshot technique, we genotyped the rs1126772, rs117291487, rs11730582, rs142608941 and rs6813526 polymorphisms of the OPN gene in all the subjects and analyzed the correlation of the five SNPs with AZS.

RESULTS

The GA genotype and A allele of the OPN gene rs1126772 were found to be correlated with the risk of AZS (GA vs AA: OR = 0.55, 95% CI: 0.35－0.86, P = 0.009; A vs G: OR = 0.64, 95% CI: 0.46－0.89, P = 0.007), and so was the CT genotype and T allele at the RS11730582 locus (CT vs TT: OR = 0.526, 95% CI: 0.34－0.82, P = 0.009; T vs C: OR = 0.60, 95% CI: 0.44－0.83, P = 0.002). Haplotype analysis showed that the AATCT haplotype decreased the risk of AZS (AATCT: OR = 0.61, 95% CI: 0.42－0.88, P = 0.008) .

CONCLUSIONS

The polymorphisms of the OPN gene RS1126772 and RS11730582 may reduce the risk of AZS.

LncRNA HOTAIR regulates the expression of E-cadherin to affect nasopharyngeal carcinoma progression by recruiting histone methylase EZH2 to mediate H3K27 trimethylation

BACKGROUND/AIM

There has been increasing evidence for the function of long non-coding RNA (lncRNA) in nasopharyngeal carcinoma (NPC). We aim to delve into the position of lncRNA HOX antisense intergenic RNA (HOTAIR), together with enhancer of zeste homolog 2 (EZH2), E-cadherin and trimethylation of lysine 27 on histone H3 (H3K27me3) in NPC.

METHODS

HOTAIR, EZH2, and E-cadherin expression in NPC tissues and cells were tested. NPC cell biological functions were examined through gain-of and loss-of function assays. The mechanism of lncRNA HOTAIR/E-cadherin/EZH2/H3K27 axis in NPC was decoded.

RESULTS

LncRNA HOTAIR and EZH2 were highly expressed in NPC, and E-cadherin was lowly expressed. Down-regulation of HOTAIR or EZH2 inhibited NPC cell progression and tumor growth. HOTAIR recruited histone methylase EZH2 to mediate trimethylation of H3K27 and regulated E-cadherin expression.

CONCLUSION

HOTAIR inhibits E-cadherin by stimulating the trimethylation of H3K27 to promote NPC cell progression through recruiting histone methylase EZH2.

Bisphenol A Exposure Disrupts Organelle Distribution and Functions During Mouse Oocyte Maturation

Bisphenol A (BPA) is one of the ubiquitous environmental endocrine disruptors (EEDs). Previous studies have shown that the reproduction toxicity of BPA could cause severe effects on the mammal oocytes and disturb the quality of mature oocytes. However, the toxic effects of BPA on the organelles of mouse oocytes have not been reported. In this study, to investigate whether BPA can be toxic to the organelles, we used different concentrations of BPA (50, 100, and 200 μM) to culture mouse oocytes in vitro. The results showed that 100 μM BPA exposure could significantly decrease the developmental capacity of oocytes. Then, we used the immunofluorescence staining, confocal microscopy, and western blotting to investigate the toxic effects of BPA on the organelles. The results revealed that mitochondrial dysfunction is manifested by abnormal distribution and decreased mitochondrial membrane potential. Moreover, the endoplasmic reticulum (ER) is abnormally distributed which is accompanied by ER stress showing increased expression of GRP78. For the Golgi apparatus, BPA-exposed dose not disorder the Golgi apparatus distribution but caused abnormal structure of Golgi apparatus, which is manifested by the decrease of GM130 protein expression. Moreover, we also found that BPA-exposed led to the damage of lysosome, which were shown by the increase of LAMP2 protein expression. Collectively, our findings demonstrated that the exposure of BPA could damage the normal function of the organelles, which may explain the reduced maturation quality of oocytes.

Podophyllotoxin Exposure Causes Spindle Defects and DNA Damage-Induced Apoptosis in Mouse Fertilized Oocytes and Early Embryos

Podophyllotoxin (PPT) is a kind of lignans extracted from the roots and stems of the genus Podophyllum from the tiller family, and it has been widely used in the treatment of condyloma acuminatum, multiple superficial epithelioma in the clinics. However, PPT has been reported to be toxic and can cause liver defects and other organ poisoning. In addition, emerging evidences also indicate that PPT has reproductive toxicity and causes female reproduction disorders. In this study, we used fertilized oocytes and tried to explore the effects of PPT on the early embryonic development with the mouse model. The results showed that exposure to PPT had negative effects on the cleavage of zygotes. Further analysis indicated that PPT could disrupt the organization of spindle and chromosome arrangement at the metaphase of first cleavage. We also found that PPT exposure to the zygotes induced excessive reactive oxygen species (ROS), suggesting the occurrence of oxidative stress. Moreover, in the PPT-exposed embryos, there was positive γH2A.X and Annexin-V signals, indicating that PPT induced embryonic DNA damage and early apoptosis. In conclusion, our results suggested that PPT could affect spindle formation and chromosome alignment during the first cleavage of mouse embryos, and its exposure induced DNA damage-mediated oxidative stress which eventually led to embryonic apoptosis, indicating the toxic effects of PPT on the early embryo development.

Effects of Lycium barbarum Polysaccharide on Endoplasmic Reticulum Stress and Oxidative Stress in Obese Mice

Background

The incidence of obesity-associated decline in male fertility has increased over the years. Lycium barbarum polysaccharide (LBP), a natural plant polysaccharide extracted from the Chinese herb L. barbarum has shown promising therapeutic effects in overcoming the same.

Aim

This study aimed to investigate the protective effect of LBP on the testes of obese mice.

Methods

Following administration of LBP to high-fat diet-induced obese mice for 35 days, serum, sperm, and testis samples were obtained for subsequent experiments. Biochemical analysis and sex hormone content determination were performed to observe changes in glycolipid metabolism and testosterone levels, respectively, in the blood. Hematoxylin and eosin staining were carried out to assess the pathological changes in the testicular tissue. Oxidative stress levels were detected using enzyme-linked immunosorbent assay and expression levels of endoplasmic reticulum stress markers were determined using western blot in the testicular tissue.

Results

Our results suggested that LBP reduced glucose levels and insulin resistance, increased testosterone levels and insulin sensitivity, and decreased testicular oxidative stress and pathological damage in obese mice. In addition, LBP down-regulated the expression of p-eIF2α, GRP78, and CHOP in the testicular tissues of obese mice.

Conclusion

Our results show that LBP is a potential novel drug for preventing male infertility caused by obesity.

Exosomal lncRNA HNF1A-AS1 affects cisplatin resistance in cervical cancer cells through regulating microRNA-34b/TUFT1 axis

Background

There is growing evidence of the role of long non-coding RNAs (lncRNAs) in cervical cancer (CC). The objective was to discuss whether exosomal lncRNA HNF1A-AS1 impacted drug resistance in CC via binding to microRNA-34b (miR-34b) and regulating TUFT1 expression.

Methods

The expression of HNF1A-AS1 in normal cervical epithelial cells, cisplatin (DDP)-sensitive cell line (HeLa/S) and DDP-resistant cell line (HeLa/DDP) cells were detected. HeLa/S and HeLa/DDP cells were interfered with HNF1A-AS1 to determine IC₅₀, proliferation, colony formation and apoptosis of CC cells. The exosomes were isolated and identified. Subcellular localization of HNF1A-AS1, expression of miR-34b and TUFT1 in receptor cells were also verified. The binding site between HNF1A-AS1 and miR-34b, together with miR-34b and TUFT1 were confirmed. Tumorigenic ability of cells in nude mice was also detected.

Results

HNF1A-AS1 was upregulated in DDP-resistant cell line HeLa/DDP. Silencing HNF1A-AS1 suppressed CC cell proliferation and promoted its apoptosis. HNF1A-AS1 was found to act as a competing endogenous RNA (ceRNA) of miR-34b to promote the expression of TUFT1. Exosomes shuttled HNF1A-AS1 promoted the proliferation and drug resistance of CC cells and inhibited their apoptosis by upregulating the expression of TUFT1 and downregulating miR-34b. Furthermore, suppressed exosomal HNF1A-AS1 in combination with DDP inhibited tumor growth in nude mice.

Conclusion

Our study provides evidence that CC-secreted exosomes carrying HNF1A-AS1 as a ceRNA of miR-34b to promote the expression of TUFT1, thereby promoting the DDP resistance in CC cells.

A simplified method for selecting a carbon-fiber electrode in pulse voltammetry

A method for selecting a usable carbon-fiber electrode using the equivalent resistance and capacitance is presented. This method uses an instrument with a PC-based look-up table for measuring the electrical characteristics of a carbon-fiber electrode in pulse voltammetry. Using this instrument, the equivalent resistance and capacitance of the carbon-fiber electrode in saturated sodium chloride solution can be obtained. This instrument includes a decade resistance box, a peak current detection and hold circuit, a half peak comparator and a decay duration counter. A look-up table is established by using RC circuits to emulate the electrochemical reaction of the carbon-fiber electrode in pulse voltammetry. The equivalent resistance is obtained from the decade resistance box according to Kirchhoff's law. Then the equivalent capacitance is determined from the decay duration counter reading and equivalent resistance with the look-up table via a PC interpolation program. After obtaining the equivalent resistance and capacitance of an electrode, the values are compared with the usable thresholds. This method provides an effective quality evaluation index of carbon-fiber electrode for the user in order to reduce electrode-induced experimental failure. The method is also available for other kinds of carbon-fiber electrodes as long as their look-up table and desired thresholds are established.