eIF3a R803K mutation mediates chemotherapy resistance by inducing cellular senescence in small cell lung cancer.

Drug resistance in small cell lung cancer (SCLC) significantly affects the efficacy of chemotherapy treatment. However, due to the lack of tumor tissue samples, especially serial tumor samples during chemotherapy, the mechanism of chemotherapy resistance has not been fully studied. Circulating tumor DNA, which can be obtained in a noninvasive manner, can complement tumor sampling approaches for research in this field. We identified an SCLC patient with acquired drug resistance from 52 SCLC patients for whom follow-up data were available. By comparing somatic mutations in circulating tumor DNA before and after chemotherapy, for the first time, we found that the somatic mutation eIF3A R803K may be related to acquired chemotherapy resistance. Then, the association between the eIF3A R803K mutation and chemotherapy resistance was confirmed by samples from 254 lung cancer patients receiving chemotherapy. We found that the eIF3a R803K mutation weakened the proliferation ability of tumor cells but increased their resistance to chemotherapy. Further studies revealed that the eIF3A R803K mutation promotes cellular senescence. In addition, fisetin showed a synergistic effect with chemotherapy in eIF3A R803K mutant cells. These results suggest that the eIF3A R803K somatic mutation has the potential to predict chemotherapy resistance in SCLC. Moreover, the eIF3A R803K mutation promotes chemotherapy resistance by inducing senescence. Furthermore, a senolytic drug, fisetin, can reverse chemotherapy resistance mediated by the eIF3A R803K mutation.

Effects of cigarette smoking on HDL quantity and function: implications for atherosclerosis.

Cigarette smoking has been identified as an independent and preventable risk factor for atherosclerosis and cardiovascular disease. Population studies have shown that plasma high density lipoprotein (HDL) cholesterol levels are inversely related to the risk of developing cardiovascular disease. Cigarette smoking is associated with reduced HDL cholesterol levels. Cigarette smoking can alter the critical enzymes of lipid transport, lowering lecithin: cholesterol acyltransferase (LCAT) activity and altering cholesterol ester transfer protein (CETP) and hepatic lipase activity, which attributes to its impact on HDL metabolism and HDL subfractions distribution. In addition, HDL is susceptible to oxidative modifications by cigarette smoking, which makes HDL become dysfunctional and lose its atheroprotective properties in smokers. Therefore, cigarette smoking has a negative impact on both HDL quantity and function, which can explain, in part, the increased risk of cardiovascular disease in smokers.

Effects of Glycolysis-Related Genes on Prognosis and the Tumor Microenvironment of Hepatocellular Carcinoma.

Background: Hepatocellular carcinoma (HCC) is a common and deadly malignancy worldwide. Current treatment methods for hepatocellular carcinoma have many disadvantages; thus, it is urgent to improve the efficacy of these therapies. Glycolysis is critical in the occurrence and development of tumors. However, survival and prognosis biomarkers related to glycolysis in HCC patients remain to be fully identified. Methods: Glycolysis-related genes (GRGs) were downloaded from "The Molecular Signatures Database" (MSigDB), and the mRNA expression profiles and clinical information of HCC patients were obtained from TCGA. Consensus clustering was performed to classify the HCC patients into two subgroups. We used the least absolute shrinkage and selection operator (LASSO) regression analysis to construct the risk signature model. Kaplan-Meier (K-M) survival analysis was performed to evaluate the prognostic significance of the risk model, and the receiver operating characteristic (ROC) curve analysis was used to evaluate the prediction accuracy. The independent prediction ability of the risk model was validated by univariate and multivariate Cox regression analyses. The differences of immune infiltrates and relevant oncogenic signaling between different risk groups were compared. Finally, biological experiments were performed to explore the functions of screened genes. Results: HCC patients were classified into two subgroups, according to the expression of prognostic-related GRGs. Almost all GRGs categorized in cluster 2 showed upregulated expressions, whereas GRGs in cluster 1 conferred survival advantages. GSEA identified a positive correlation between cluster 2 and the glycolysis process. Ten genes were selected for risk signature construction. Patients were assigned to high-risk and low-risk groups based on the median risk score, and K-M survival analysis indicated that the high-risk group had a shorter survival time. Additionally, the risk gene signature can partially affect immune infiltrates within the HCC microenvironment, and many oncogenic pathways were enriched in the high-risk group, including glycolysis, hypoxia, and DNA repair. Finally, in vitro knockdown of ME1 suppressed proliferation, migration, and invasion of hepatocellular carcinoma cells. Conclusion: In our study, we successfully constructed and verified a novel glycolysis-related risk signature for HCC prognosis prediction, which is meaningful for classifying HCC patients and offers potential targets for the treatment of hepatocellular carcinoma.

Protective effect of HDL on endothelial NO production: the role of DDAH/ADMA pathway.

Accumulating studies have demonstrated that the dimethylarginine dimethylaminohydrolase/asymmetric dimethylarginine (DDAH/ADMA) system is a novel pathway for modulating nitric oxide (NO) production. The aim of this study was to investigate whether the protective effect of high density lipoprotein (HDL) on endothelial NO production was related to its effect on DDAH/ADMA pathway. Human umbilical vein endothelial cells (HUVECs) were prior exposed to HDL (10, 50, or 100 µg/ml) for 1 h, and then incubated with oxidized low density lipoprotein (ox-LDL) (100 µg/ml) for 24 h. The cultured medium was collected for measuring the concentration of NO and ADMA. The cells were collected for measuring the mRNA and protein expression of DDAH-II as well as DDAH activity. HUVECs treated with ox-LDL (100 µg/ml) for 24 h significantly decreased the concentration of NO, the mRNA and protein expression of DDAH-II as well as DDAH activity and increased the level of ADMA. Pretreatment with HDL (10, 50, or 100 µg/ml) could counteract these changes induced by ox-LDL (100 µg/ml). HDL significantly increased the attenuated endothelial cell NO production induced by ox-LDL, which was attributed to its effect on DDAH/ADMA pathway.

Protective effect of neferine on endothelial cell nitric oxide production induced by lysophosphatidylcholine: the role of the DDAH-ADMA pathway.

Neferine, extracted from the seed embryo of Nelumbo nucifera Gaertn., has multiple cardiovascular pharmacological effects. The dimethylarginine dimethylaminohydrolase (DDAH) - asymmetric dimethylarginine (ADMA) system is a novel pathway for modulating nitric oxide (NO) production. The aim of this study was to investigate whether the protective effect of neferine on endothelial NO production was related to the DDAH-ADMA pathway. Human umbilical vein endothelial cells (HUVECs) were first exposed to neferine (0.1, 1.0, or 10.0 µmol/L) for 1 h, and then incubated with lysophosphatidylcholine (LPC; 10 µg/mL) in the presence of neferine for 24 h. The medium was collected for measuring the levels of NO, maleic dialdehyde (MDA), as well as ADMA. The endothelial cells were collected for measuring DDAH activity and the level of reactive oxygen species (ROS). LPC significantly decreased NO concentration and DDAH activity and increased the levels of ADMA, ROS, and MDA. Neferine could partially counteract the changes induced by LPC. These findings suggested that neferine could modulate the DDAH-ADMA pathway via its antioxidant properties, which was involved in its beneficial effect on endothelial NO production.

[The effect of erythromycin on transforming growth factor-ß(1) and secretory leukocyte proteinase inhibitor in a rat model of chronic obstructive pulmonary disease].

OBJECTIVE: To study the protective mechanism of erythromycin in the process of COPD. METHODS: Thirty-six male Wistar rats, grade SPF, weight (220 ± 20) g, were randomly divided into 3 groups, 12 each: a control group, a COPD model group and an erythromycin treated group. Measurement of rat pulmonary function and the pathological changes were performed, and the expression of transforming growth factor-ß(1) (TGF-ß(1)) and secretory leukocyte proteinase inhibitor (SLPI) in the lung of rats were evaluated by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). Analysis of variance, pairwise comparison between groups using SNK-q test, Pearson linear correlation analysis were carried out for statistical analysis. RESULTS: The rats in the COPD model group showed sign of less activity, loss of appetite and weight, dry and yellow hair, and sometimes wheezing, which were less or milder in the group treated with erythromycin. FEV(0.3)/FVC [(58 ± 7)%] and Cdyn [(0.16 ± 0.07) L/cm H2O, 1 cm H2O = 0.098 kPa] were significantly lower in the model group as compared to the control group [(83 ± 7)% and (0.33 ± 0.16) L/cm H2O], RI [(0.69 ± 0.14) cm H2O×L(-1)×s(-1)], but was significantly higher than the control group [(0.33 ± 0.11) cm H2O×L(-1)×s(-1)]. FEV(0.3)/FVC [(65 ± 9)%] and Cdyn [(0.23 ± 0.08) L/cm H2O] were significantly higher in the erythromycin treated group as compared to the model group [(58 ± 7)% and (0.16 ± 0.07) L/cm H2O], RI [(0.50 ± 0.13) cm H2O×L(-1)×s(-1)], but was significantly lower than the model group [(0.69 ± 0.14) cm H2O×L(-1)×s(-1)]. The expression of TGF-ß(1)protein (integral optical density value) and mRNA (absorbance value) (6.7 ± 1.5 and 0.45 ± 0.13) were lower in the erythromycin treated group as compared to the model group (10.7 ± 1.9 and 0.66 ± 0.18), but the expression of SLPI protein (integral optical density value) and mRNA (absorbance value) (9.9 ± 1.7 and 0.69 ± 0.34) were higher than those of the model group (8.1 ± 1.7 and 0.41 ± 0.27). The expressions of TGF-ß(1)and SLPI were negatively associated (r = -0.686, P < 0.05). CONCLUSIONS: The expression of SLPI was decreased but the expression of TGF-ß(1)was increased significantly in the bronchial and lung tissues of rats with COPD. Airway inflammation was inhibited by erythromycin which was able to reduce the inhibitory effect of TGF-ß(1)to SLPI, indicating a partial protective effect of erythromycin.

[Endoplasmic reticulum stress and related apoptosis in the lungs of a chronic obstructive pulmonary disease rat model].

OBJECTIVE: To study the endoplasmic reticulum stress (ERS) and the apoptosis of alveolar epithelial cells in a COPD rat model. METHODS: Twenty-four Wistar rats were divided into a control group and a COPD group at random. The COPD rat model was established by intratracheal instillation of lipopolysaccharide (LPS) twice and exposure to cigarette smoke daily. The spirometry was conducted and the pathological changes were observed after the model was established. The levels of glucose regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP) mRNA were detected by reverse transcription-polymerase chain reaction (RT-PCR). The protein expression of GRP78, CHOP and caspase-12 was detected by Western blot. TdT-mediated dUTP nick end labeling (TUNEL) was used to analyze alveolar epithelial cell apoptosis. Comparisons between the two groups were performed by t-test. RESULTS: Significant decrease of FEV(0.3)/FVC [(60 ± 6)%] and dynamic compliance of lung (CLdyn) [(0.17 ± 0.02) cm H2O×ml(-1)×s(-1)], and increase of airway resistance [(0.64 ± 0.07) ml/cm H2O] were found in the COPD group compared with the control group [(83 ± 7)%, (0.31 ± 0.03) cm H2O×ml(-1)×s(-1), (0.32 ± 0.03) ml/cm H2O] (t = -14.532 - 11.619, P < 0.05). GRP78 mRNA and CHOP mRNA densitometry [(0.65 ± 0.07), (0.79 ± 0.06)] were significantly increased in the COPD group compared with the control group [(0.21 ± 0.04), (0.07 ± 0.04), respectively] (t = -19.102 and -32.573, P < 0.05). GRP78, CHOP, and active caspase-12 protein densitometry (0.83 ± 0.06, 0.82 ± 0.06 and 0.81 ± 0.07) were significantly increased in the COPD group compared with the control group [(0.33 ± 0.05, 0.05 ± 0.03 and 0.24 ± 0.06), respectively] (t = -40.866 - -22.070, P < 0.05). More apoptotic alveolar epithelial cells were found in the COPD group [(32.4 ± 3.7)%] than in the control group [(6.2 ± 0.9)%] (t = -23.852, P < 0.05). CONCLUSIONS: ERS was triggered in the lung tissues of COPD rats, especially in the alveolar epithelial cells. Alveolar epithelial cell apoptosis was increased in the COPD group. The ERS mediated apoptosis pathway may participate in the alveolar epithelial cell apoptosis in COPD.

Non-Coding RNA Polymorphisms (rs2910164 and rs1333049) Associated With Prognosis of Lung Cancer Under Platinum-Based Chemotherapy.

Purpose: Lung cancer is the largest cause of cancer deaths in the world. Platinum-based chemotherapy is a foundation of first-line chemotherapy. However, the prognosis of lung cancer treated with platinum-based chemotherapy is still a challenge. Single nucleotide polymorphism of non-coding RNA has the potential to be a biomarker, but its effectiveness has yet to be comprehensively assessed. In this study, we explored the association between polymorphisms of non-coding RNA and prognosis of lung cancer patients receiving platinum-based chemotherapy. Materials and Methods: For 446 lung cancer patients receiving platinum-based chemotherapy, 22 single nucleotide polymorphisms of microRNA and long noncoding RNA were genotyped by MALDI-TOF mass spectrometry. Cox regression analysis, Kaplan-Meier method, and long-rank test have been performed to assess the association of overall and progression-free survival with polymorphisms. Results: In the additive and dominant models, genetic polymorphism of ANRIL rs1333049 (G > C) was significantly associated with progression-free survival. Additive model: CC vs GC vs GG [HR = 0.84, p = 0.021, 95% CI (0.73-0.97)]; Recessive model: CC vs GG + GC [HR = 0.77, p = 0.026, 95% CI (0.61-0.97)]. In the dominant model, compared with the CC genotype patients, lower risk of death [HR = 0.81, p = 0.036, 95% CI (0.66-0.99)] and lower risk of progression [HR = 0.81, p = 0.040, 95% CI (0.67-0.99)] have been observed on the patients with CG or GG genotype in miR-146A rs2910164. Conclusion: Our research demonstrated the potential of using ANRIL rs1333049 (G > C) and miR-146A rs2910164 (C > G) as biomarkers to support the prediction of a better prognosis for lung cancer patients receiving platinum-based chemotherapy.

The role of single strand break repair pathways in cellular responses to camptothecin induced DNA damage.

Efficient DNA repair is critical for cell survival following exposure to DNA topoisomerase I (Top1) inhibitors camptothecin, a nature product from which the common chemotherapeutic drugs irinotecan and topotecan are derived. The camptothecin-derived agents exert their antitumor activities by specifically stabilizing the Top1-DNA covalent complexes (Top1cc) and blocking the DNA religation step. When exposed to these DNA damage agents, tumor cells quickly activate DNA damage response. This allows sufficient time to remove the Top1ccs and prevent tumor cells from apoptosis. Several repair pathways have been implicated in this process. One of the most relevant repair modes is DNA single strand break repair (SSBR) pathway. The expression level or mutagenesis of specific repair factors involved in SSBR pathway may play an indispensable role in individual's capacity of repairing camptothecin induced DNA damage. Therefore, understanding of the tolerance pathways counteracted to camptothecin cytotoxicity is crucial in alleviating chemotherapy resistance. This review focus on the SSBR pathway in repair camptothecin induced DNA damage, aiming to provide insights into the potential molecular determinants of camptothecin chemosensitivity.

Melatonin protects against sepsis-induced cardiac dysfunction by regulating apoptosis and autophagy via activation of SIRT1 in mice.

AIMS: The apoptosis and autophagy play an important role in the pathogenesis of sepsis-induced cardiac dysfunction. Previous studies have demonstrated that melatonin protects against cardiac dysfunction during sepsis. In addition, silent information regulator 1 (SIRT1) is a therapeutic target for sepsis-induced myocardial dysfunction. The aims of this study were to investigate whether SIRT1 was involved in melatonin's cardioprotection during sepsis and the mechanisms. MATERIALS AND METHODS: In this study, twenty-four male C57BL/6 mice were randomly assigned to four groups: Control group, LPS group, LPS + Melatonin group and LPS + Melatonin + EX527 group. Mice were treated with lipopolysaccharide for 8 h with or without melatonin or EX527. The cardiac function, myocardial injury biomarkers, cardiac histopathology, cardiomyocyte apoptosis, autophagosome as well as the protein expressions of SIRT1, cleaved caspase-3, LC3-II/LC3-I ratio and p62 in the myocardium were assayed. KEY FINDINGS: The results demonstrated that melatonin significantly improved cardiac function, decreased creatine kinase (CK) and creatine kinase-MB (CK-MB) levels, attenuated myocardial architecture destruction, inhibited cardiomyocyte apoptosis and increased cardiac autophagy as compared with the LPS group. In addition, melatonin significantly increased SIRT1 protein expression in the myocardium of mice with sepsis, while inhibition of SIRT1 by EX527 abolished melatonin's cardioprotection during sepsis. SIGNIFICANCE: In this study, we found that melatonin protected against sepsis-induced cardiac dysfunction by regulating apoptosis and autophagy via activation of SIRT1 in mice.

Circular RNA screening from EIF3a in lung cancer.

Eukaryotic initiation factor 3 (EIF3) is one of the largest and most complex translation initiation factors, which consists of 13 subunits named eukaryotic translation initiation factor 3 subunit A (EIF3a) to EIF3m. EIF3a is the largest subunit of EIF3. Previous studies suggested that EIF3a is a housekeeping gene, recent results have found that EIF3a is closely related to the tumorigenesis and drug resistance. Circular RNAs (circRNAs) derived from biologically important gene can play an important role in gene regulation. However, the mechanism underlying circRNAs' biological functions is not well understood yet. In this work, we screened 31 EIF3a-derived circRNAs, in which two circEIF3as were identified to be correlated with cisplatin drug sensitivity in lung cancer. Two circEIF3as were found involved in RNA-binding proteins-mediated biological processes and may be related to translational regulation according to bioinformatics analyses. CircEIF3as, the transcriptional initiation factor EIF3a transcribed circRNAs, are associated with both drug sensitivity and translation regulation. These findings mean that they may have a functional synergy effect with EIF3a or be valuable therapeutic targets for treatment like EIF3a. This is the first study that exploits circRNAs screening from EIF3a in lung cancer, our findings provide a novel perspective on the function of EIF3a and circEIF3as in lung cancer.

Salubrinal protects against cigarette smoke extract-induced HBEpC apoptosis likely via regulating the activity of PERK-eIF2α signaling pathway.

BACKGROUND AND AIMS: Endoplasmic reticulum (ER) stress plays an important role in cigarette smoke extract (CSE)-induced apoptotic cell death, which is an important pathogenic factor of chronic obstructive pulmonary disease (COPD). The aim of this study was to explore the role of the PERK-eIF2 pathway in CSE-induced human bronchial epithelial (HBE) cell apoptosis and to evaluate the protective effects and possible mechanism of salubrinal (Sal) on CSE-induced HBE cell apoptosis. METHODS: Normal human bronchial epithelial cells (HBEpC) were cultured and then treated with CSE alone or together with Sal or preincubated with or without PERK siRNA. Expressions of p-PERK/PERK, p-eIF2α/eIF2α, and caspase 3 and 4 were detected with PCR, Western blot, and immunofluorescence. Apoptosis was detected using AnnexinV-PI flow cytometry. RESULTS: CSE induced apoptotic cell death and caused a dynamic change in PERK-eIF2α pathway activity following the course of CSE exposure. The knockdown of PERK suppressed the expression of both PERK and p-eIF2a and caused a great increase in cell apoptosis. Sal could eliminate the effects of PERK knockdown, protecting the cells against the CSE insult, and this protection was accomplished through maintaining the homeostasis of PERK- eIF2α pathway. CONCLUSIONS: PERK-eIF2α pathway mediates the CSE-induced HBE cell apoptosis. The intactness of PERK-eIF2α pathway is crucial for HBE cell survival under CSE insult. Sal can protect against CSE-induced HBE cell apoptosis, and this effect is likely achieved through maintaining the homeostasis of PERK- eIF2α pathway.