Potentially functional genetic variants in PLIN2, SULT2A1 and UGT1A9 genes of the ketone pathway and survival of nonsmall cell lung cancer

Plin2 inhibits autophagy via activating AKT/mTOR pathway in non-small cell lung cancer

Perilipin 2 (Plin2) is known to be dysregulated in several human malignancies, which facilitates cancer progression. Recent studies have found that the abnormal expression of Plin2 is associated with poor prognosis of non-small cell lung cancer (NSCLC). However, the specific role of Plin2 and its underlying mechanism remain unclear. This study revealed that Plin2 expression was low in NSCLC tissues, and its relatively higher expression indicated larger tumor size and poorer prognosis. In vitro experiments proved that Plin2 promoted NSCLC cellular proliferation and inhibited autophagy by activating the AKT/mTOR pathway. Meanwhile, treatment with the AKT phosphorylation promoter or inhibitor neutralized the influence of Plin2 depletion or over-expression on proliferation and autophagy, respectively. In vivo study showed that Plin2 stimulated subcutaneous tumorigenesis of NSCLC cells in nude mice. Collectively, this study clarified the carcinogenic role of Plin2 and its molecular mechanism in NSCLC progression, which may facilitate a targeted therapy in the future.

Single-Cell Profiling of Tumor-Associated Neutrophils in Advanced Non-Small Cell Lung Cancer

Purpose

Neutrophils act as a non-negligible regulator in the initiation and progression of malignancies, playing bifacial roles in the process. Thus, to understand the heterogeneity of tumor-associated neutrophils (TANs) comprehensively in advanced non-small cell lung cancer (NSCLC) at single-cell resolution is necessary and urgent.

Materials and Methods

We applied single-cell RNA-sequencing (scRNA-seq) to portray the subtype-specific transcriptome landscape of TANs in advanced NSCLC using nine freshly obtained specimens. The scRNA-seq data were further processed for pseudo-time analysis to depict the developmental trajectory of TANs. Meanwhile, the interplay between TANs and other cell types within tumor microenvironment (TME) was revealed by intercellular interaction analysis.

Results

Seven distinct TAN subtypes were defined, of which, the N3 cluster was considered inflammatory phenotype expressing genes encoding multiple chemotactic cytokines, and correlated with inferior overall survival, indicating that N3 might be a pro-tumorigenic TAN subtype. N1 and N5 clusters were considered to be well differentiated and mature neutrophils based on CXCR2 expression and pseudo-time patterns, and both accounted for relatively high proportions in lung adenocarcinoma. In addition, genes related to neutrophil differentiation were discovered. We also found that TAN subtypes interacted most closely with macrophages through chemokine signaling pathways within TME.

Conclusion

Our study refined TAN subtypes and mapped the transcriptome landscape of TANs at single-cell resolution in advanced NSCLC, collectively indicating the heterogeneity of TANs in NSCLC. Neutrophil differentiation- and maturation-related genes were also discovered, which shed light on different functions of TAN subclones in tumor immune escape, and may further provide novel targets for immunotherapy.

Learning and Investigation of the Role of Angiotensin-Converting Enzyme in Radiotherapy for Nasopharyngeal Carcinoma

Ionizing radiation (IR) is an important treatment for nasopharyngeal carcinoma (NPC) that mainly kills tumor cells by producing large amounts of reactive oxygen species (ROS). Intracellular ROS levels affect the sensitivity of tumor cells to IR. Recently, angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-converting enzyme (ACE) have been found to affect the intracellular levels of ROS. Therefore, we performed a health informatics assessment of ACE in the TCGA database. We explored the effect of ACE in NPC cells. We found that either knockdown of ACE or inhibition of ACE by enalaprilat could decrease ROS levels in NPC cells. Furthermore, knockdown of ACE or inhibition of ACE by enalaprilat could reduce IR-induced ROS levels. ACE knockdown or inhibition reduced IR-induced DNA damage and apoptosis. ACE overexpression increased the level of ROS in NPC cells and further increased sensitivity to IR. These findings indicate that ACE influences the effect of IR by regulating the level of ROS in NPC cells.

Novel Genetic Variants in TP37, PIK3R1, CALM1, and PLCG2 of the Neurotrophin Signaling Pathway Are Associated with the Progression from Mild Cognitive Impairment to Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD) is a common neurodegenerative disease and mild cognitive impairment (MCI) is considered as the prodromal stage of AD. Previous studies showed that changes in the neurotrophin signaling pathway could lead to cognitive decline in AD. However, the association of single nucleotide polymorphisms (SNPs) in genes that are involved in this pathway with AD progression from MCI remains unclear.

OBJECTIVE

We investigated the associations between SNPs involved in the neurotrophin signaling pathway with AD progression.

METHODS

We performed single-locus analysis to identify neurotrophin-signaling-related SNPs associated with the AD progression using 767 patients from the Alzheimer's Disease Neuroimaging Initiative study and 1,373 patients from the National Alzheimer's Coordinating Center study. We constructed polygenic risk scores (PRSs) using the identified independent non-APOE SNPs and evaluated its prediction performance on AD progression.

RESULTS

We identified 25 SNPs significantly associated with AD progression with Bayesian false-discovery probability ≤0.8. Based on the linkage disequilibrium clumping and expression quantitative trait loci analysis, we found 6 potentially functional SNPs that were associated with AD progression independently. The PRS analysis quantified the combined effects of these SNPs on longitudinal cognitive assessments and biomarkers from cerebrospinal fluid and neuroimaging. The addition of PRSs to the prediction model for 3-year progression to AD from MCI significantly increased the predictive accuracy.

CONCLUSION

Genetic variants in the specific genes of the neurotrophin signaling pathway are predictors of AD progression. eQTL analysis supports that these SNPs regulate expression of key genes involved in the neurotrophin signaling pathway.

Novel genetic variants of SYK and ITGA1 related lymphangiogenesis signaling pathway predict non-small cell lung cancer survival

Although lymphangiogenesis is a vital step in lung cancer metastasis, the association between lymphangiogenesis and non-small cell lung cancer (NSCLC) survival remains unclear. Since single-nucleotide polymorphisms (SNPs) have been reported to predict NSCLC survival, we investigated associations between SNPs in lymphangiogenesis-related pathway genes and NSCLC survival in a discovery genotyping dataset of 1,185 patients from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial and validated the findings in another genotyping dataset of 984 patients from the Harvard Lung Cancer Susceptibility Study. We evaluated associations between 34,509 genetic variants (3252 genotyped and 31,257 imputed) in 247 genes involved in lymphangiogenesis-related pathway and NSCLC survival. After validation, we finally identified two independent SNPs (SYK rs11787670 A>G and ITGA1 rs67715745 T>C) to be significantly associated with NSCLC overall survival (OS), with adjusted hazards ratios of 0.77 and 0.83 (95% confidence interval =0.66-0.90, P=7.20×10^-4) and 0.84 (95% confidence interval =0.75-0.92, P=3.50×10^-4), respectively. Moreover, an increasing number of combined protective alleles of these two SNPs was significantly associated with an improved NSCLC OS and disease-specific survival (DSS) in the PLCO dataset (P _trend=0.011 and 0.006, respectively). Furthermore, the addition of these protective alleles to the prediction model for the 5-year survival increased the time-dependent area under the curve both from 87% to 87.67% for OS (P=0.029) and from 88.54% to 89.06% for DSS (P=0.022). Subsequent expression quantitative trait loci (eQTL) functional analysis revealed that the rs11787670 G allele was significantly associated with an elevated SYK mRNA expression in normal tissues. Additional analyses suggested a suppressor role for both SYK and ITGA1 in NSCLC survival. Collectively, these findings indicated that SYK rs11787670 A>G and ITGA1 rs67715745 T>C may be independent prognostic factors for NSCLC survival once further validated.

Hypermethylation of tumor necrosis factor decoy receptor gene in non-small cell lung cancer

Abnormal methylation of the TNFRSF10C and TNFRSF10D genes has been observed in numerous types of cancer; however, no studies have investigated the methylation of these genes in non-small cell lung cancer (NSCLC). The aim of the present study was to investigate the association between TNFRSF10C and TNFRSF10D methylation and NSCLC. Methylation levels of 44 pairs of NSCLC tumor tissues and distant non-tumor tissues were analyzed using quantitative methylation specific PCR and methylation reference percentage values (PMR). The methylation levels of the TNFRSF10C gene in NSCLC tumor tissue samples were significantly higher compared with those in the distant non-tumor tissues (median PMR, 2.73% vs. 0.75%; P=0.013). Subgroup analysis demonstrated that the methylation levels of TNFRSF10C in tumor tissues from male patients were significantly higher compared with those in distant non-tumor tissues (median PMR, 2.73% vs. 0.75%; P=0.041). The levels of TNFRSF10C methylation were also higher in the tumor tissues of patients who were non-smokers compared with their distant non-tumor tissues (median PMR, 2.50% vs. 0.63%; P=0.013). TNFRSF10C methylation levels were higher in the tumor tissues from male patients compared with those from female patients (median PMR, 2.50% vs. 0.63%; P=0.031). However, no significant differences in the methylation levels of the TNFRSF10D gene were observed between the sexes. Using the cBioPortal and The Cancer Genome Atlas lung cancer data, it was demonstrated that TNFRSF10C methylation levels were inversely correlated with TNFRSF10C mRNA expression levels (r=-0.379; P=0.008). In addition, demethylation of lung cancer cell lines A549 and NCI-H1299 using 5'-aza-deoxycytidine further confirmed that TNFRSF10C hypomethylation was associated with significant upregulation of TNFRSF10C mRNA expression levels [A549 fold-change (FC)=8; P=1.0×10^-4; NCI-H1299 FC=3.163; P=1.143×10^-5]. A dual luciferase reporter gene assay was also performed with the insert of TNFRSF10C promoter region, and the results revealed that the TNFRSF10C gene fragment significantly enhanced the transcriptional activity of the reporter gene compared with that in the control group (FC=1.570; P=0.032). Overall, the results of the present study demonstrated that hypermethylation of TNFRSF10C was associated with NSCLC.