A prognostic model based on ferroptosis-related long non-coding RNA signatures and immunotherapy responses for non-small cell lung cancer.

OBJECTIVE: Non-small cell lung cancer (NSCLC) ranks high in the incidence of malignant tumors, with limited treatment options and poor prognosis. Ferroptosis is a newly discovered cell death mechanism based on iron and reactive oxygen species (ROS). The role of ferroptosis-related long non-coding RNAs (lncRNAs) and associated prognostic mechanisms in NSCLC require investigation. MATERIALS AND METHODS: We constructed a prognostic multi-lncRNA signature based on ferroptosis-related differentially expressed lncRNAs in NSCLC. The levels of ferroptosis-related lncRNA in normal lung cells and lung adenocarcinoma cells were verified by RT-PCR. RESULTS: We identified eight differentially expressed lncRNAs associated with NSCLC prognosis. The expression of AC125807.2, AL365181.3, AL606489.1, LINC02320, and AC099850.3 was upregulated, while SALRNA1, AC026355.1, and AP002360.1 were downregulated in NSCLC cell lines. Kaplan-Meier analysis showed that a high-risk patient group was associated with poor NSCLC prognosis. A risk assessment model based on ferroptosis-related lncRNAs was superior to NSCLC prognosis based on traditional clinicopathological features. Gene Set Enrichment Analysis (GSEA) identified immune- and tumor-related pathways in low-risk group patients. In addition, The Cancer Genome Atlas (TCGA) showed that T cell function during APC co-inhibition, APC co-stimulation, chemokine receptor (CCR), MHC class I, parainflammation, T cell co-inhibition, and check-point expression differed significantly between low- and high-risk groups. M6A-related mRNA comparisons between these groups also revealed significant differences in ZC3H13, RBM15, and METTL3 expression. CONCLUSIONS: Our new model of lncRNA-associated ferroptosis effectively predicted NSCLC prognoses.

Construction of a hypoxic immune microenvironment associated gene-based model for prognosis prediction of lung adenocarcinoma.

OBJECTIVE: Lung adenocarcinoma (LUAD) accounts for the majority of cancer deaths worldwide, with a high incidence rate and mortality. It is highly important to develop biomarker model to accurately predict the prognosis. MATERIALS AND METHODS: RNA-Seq data and clinical follow-up data of LUAD were downloaded from The Cancer Genome Atlas (TCGA) database. Hypoxia-related gene sets were collected from the Gene Set Enrichment Analysis (GSEA) website. A gene signature model was established using the Limma package in the R software, univariate and multivariate survival analyses, and least absolute shrinkage and selection operator (LASSO) algorithms. RESULTS: Two hypoxia subtypes (C1 and C2) were classified according to the expressions of 55 prognostic hypoxic-related genes. Differentially expressed genes (DEGs) between two hypoxia subtypes and immune group were analyzed. Then, 390 DEGs related to hypoxic immune microenvironment were filtered. According to hypoxia type and immune type, the samples were classified into hypoxia-high & immune-low group, hypoxia-low & immune-high group. Based on these differentially expressed genes (DEGs), a 5-genes signature model, which showed a stable prediction performance on datasets of different platforms and immunotherapy datasets, was finally developed. Meanwhile, it demonstrated a better performance compared with other existing models. The AUC of the 5-gene signature was high in both the training dataset and 4 independent validation datasets and was confirmed as a clinical feature-independent prognostic model. CONCLUSIONS: This study developed a hypoxic immune microenvironment associated gene-based model for prognostic prediction of LUAD, providing clinicians with a reliable prognostic assessment tool and facilitating clinical treatment decision-making.

LINC00324 exerts tumor-promoting functions in lung adenocarcinoma via targeting miR-615-5p/AKT1 axis.

OBJECTIVE: The underlying mechanism of long non-coding RNA (lncRNA) in lung adenocarcinoma (LAC) has not been fully understood yet. Hence, this study aimed to determine the biological function of LINC00324 in LAC and to provide a novel diagnostic and therapeutic target for it. PATIENTS AND METHODS: The expression level of LINC00324 in 87 paired LAC tumor tissues and matched para-tumor tissues was detected using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Cell counting kit-8 (CCK-8) assay was employed to analyze the cell proliferative ability, whereas flow cytometry was performed to detect cell apoptotic rate. Cell metastasis change was measured using wound-healing assay and transwell assay. Luciferase reporter gene assay and Western blotting analysis were utilized to investigate the underlying mechanism of LINC00324 in LAC. RESULTS: LINC00324 was highly expressed in LAC tissues compared with the para-tumor samples. Identically, the expression level of LINC00324 was significantly higher in LAC cell lines. The overexpression of LINC00324 promoted cell proliferation and inhibited cell apoptosis of LAC cells, while knockdown of LINC00324 presented the opposite effect. Up-regulation of LINC00324 accelerated cell migration and invasion, but down-regulation of LINC0324 decreased cell metastasis of LAC cells. Furthermore, miR-615-5p was found to be regulated by LINC00324 and inhibited AKT1 expression, indicating that LINC00324 promoted cell progression via affecting the miR-615-5p/AKT1 pathway. CONCLUSIONS: LINC00324 was significantly over-expressed in LAC tissues and cells. It promoted proliferation and metastasis but inhibited cell apoptosis of LAC cells via sponging miR-615-5p to promote AKT1 expression. Our results demonstrated LINC00324 as a novel diagnostic and therapeutic target for LAC.

Functional and mutational analyses of an omega-class glutathione S-transferase (GSTO2) that is required for reducing oxidative damage in Apis cerana cerana.

Glutathione S-transferases perform a variety of vital functions, particularly in reducing oxidative damage. Here, we investigated the expression patterns of Apis cerana cerana omega-class glutathione S-transferase 2 (AccGSTO2) under various stresses and explored its connection with antioxidant defences. We found that AccGSTO2 knockdown by RNA interference triggered increased mortality in Ap. cerana cerana, and immunohistochemistry revealed significantly decreased AccGSTO2 expression, particularly in the midgut and fat body. Further analyses indicated that AccGSTO2 knockdown resulted in decreases in catalase and glutathione reductase activities, ascorbate content and the ratio of reduced to oxidized glutathione, and increases in H2 O2 , malondialdehyde and carbonyl contents. We also analysed the transcripts of other antioxidant genes and found that many genes were down-regulated in the AccGSTO2 knockdown samples, revealing that AccGSTO2 may be indispensable for attaining a normal lifespan by enhancing cellular oxidative resistance. In addition, the roles of cysteine residues in AccGSTO2 were explored using site-directed mutagenesis. Mutants of Cys(28) and Cys(124) significantly affected the enzyme and antioxidant activities of AccGSTO2, which may be attributed to the changes in the spatial structures of mutants as determined by homology modelling. In summary, these observations provide novel insight into the structural and functional characteristics of GSTOs.

Identification of a novel NPR1-like gene from Nicotiana glutinosa and its role in resistance to fungal, bacterial and viral pathogens.

The NPR1 or NPR1-like genes play a pivotal role in systemic acquired resistance in plants. Here, we isolated and identified a novel tobacco (Nicotiana glutinosa) NPR1-like gene (designated as NgNPR3). The full-length cDNA is 2049 bp in length with a 1767 bp open reading frame which encodes a 588 amino acids protein with an estimated molecular mass of 66 kDa and a calculated pI of 7.14. Homology analysis suggested that the NgNPR3 protein shares significant similarity to AtNPR3 of Arabidopsis. Transient expression assay of NgNPR3-GFP fusion gene in onion epidermal cells revealed that the NgNPR3 protein was localized to the cytoplasm and moved into the nucleus after redox change. RT-PCR results indicated that NgNPR3 was up-regulated after treatment with SA, INA, H(2)O(2,) and MeJA, which play important roles in various resistance responses in tobacco. Transcriptional level of NgNPR3 was also up-regulated after inoculation with Rhizoctonia solani, Phytophthora parasitica, Alternaria alternata, Pseudomonas solanacearum, and potato virus Y (PVY), respectively. When NgNPR3 was overexpressed in N. tabacum cv. Samsun plants, the transgenic plants showed enhanced resistance to the pathogens A. alternate, P. solanacearum and PVY. Furthermore, NgNPR3-mediated disease resistance is dosage-dependent. Our results suggest that NgNPR3 could be a putative NPR1-like gene, and might play an important role in resistance to a broad range of pathogens in tobacco.