m6A modification of CDC5L promotes lung adenocarcinoma progression through transcriptionally regulating WNT7B expression.

Cell division cycle 5-like (CDC5L) protein is implicated in the development of various cancers. However, its role in the progression of lung adenocarcinoma (LUAD) remains uncertain. Our findings revealed frequent upregulation of CDC5L in LUAD, which correlated with poorer overall survival rates and advanced clinical stages. In vitro experiments demonstrated that CDC5L overexpression stimulated the proliferation, migration, and invasion of LUAD cells, whereas CDC5L knockdown exerted suppressive effects on these cellular processes. Furthermore, silencing CDC5L significantly inhibited tumor growth and metastasis in a xenograft mouse model. Mechanistically, CDC5L activates the Wnt/ß-catenin signaling pathway by transcriptionally regulating WNT7B, thereby promoting LUAD progression. Besides, METTL14-mediated m6A modification contributed to CDC5L upregulation in an IGF2BP2-dependent manner. Collectively, our study uncovers a novel molecular mechanism by which the m6A-induced CDC5L functions as an oncogene in LUAD by activating the Wnt/ß-catenin pathway through transcriptional regulation of WNT7B, suggesting that CDC5L may serve as a promising prognostic marker and therapeutic target for LUAD.

METTL14-mediated m6A mRNA modification of G6PD promotes lung adenocarcinoma.

METTL14 functions as an RNA methyltransferase involved in m6A modification, influencing mRNA biogenesis, decay, and translation processes. However, the specific mechanism by which METTL14 regulates glucose-6-phosphate dehydrogenase (G6PD) to promote the progression of lung adenocarcinoma (LUAD) is not well understood. Quantitative measurement and immunohistochemistry (IHC) analysis have demonstrated higher levels of m6A in LUAD tissues compared to adjacent normal tissues. Additionally, the expression of METTL14 was significantly increased in LUAD tissues. In LUAD cell lines, both METTL14 and m6A levels were elevated compared to normal human lung epithelial cells. Knockdown of METTL14 markedly reduced LUAD cell proliferation, migration, and invasion. Conversely, overexpression of METTL14, but not the mutant form, significantly enhanced these cellular processes in LUAD. In vivo studies using nude mice with subcutaneously transplanted LUAD cells demonstrated that stable METTL14 knockdown led to notably reduced tumor volume and weight, along with fewer Ki67-positive cells and lung metastatic sites. Importantly, METTL14 knockdown reduced glycolytic activity in LUAD cells. Through a combination of RNA sequencing and MeRIP-sequencing, we identified numerous altered genes and confirmed that IGF2BP2 enhances G6PD mRNA stability after METTL14-mediated m6A modification, thereby promoting tumor growth and metastasis. Moreover, LUAD patients with higher levels of G6PD had poorer overall survival (OS). In conclusion, our study indicates that METTL14 upregulates G6PD expression post-transcriptionally through an m6A-IGF2BP2-dependent mechanism, thereby stabilizing G6PD mRNA. These findings propose potential diagnostic biomarkers and effective targets for anti-metabolism therapy in LUAD.

Construction of lung cancer serum markers based on ReliefF feature selection.

Serum miRNAs are available clinical samples for cancer screening. Identifying early serum markers in lung cancer (LC) is essential for patients' early diagnosis and clinical treatment. Expression data of serum miRNAs of lung adenocarcinoma (LUAD) patients and healthy individuals were downloaded from the Gene Expression Omnibus (GEO). These data were normalized and subjected to differential expression analysis to obtain differentially expressed miRNAs (DEmiRNAs). The DEmiRNAs were subsequently subjected to ReliefF feature selection, and subsets closely related to cancer were screened as candidate feature miRNAs. Thereafter, a Gaussian Naive Bayes (NB), Support Vector Machine (SVM), and Random Forest (RF) classifier were constructed based on these candidate feature miRNAs. Then the best diagnostic signature was constructed through NB combined with incremental feature selection (IFS). Thereafter, these samples were subjected to principal component analysis (PCA) based on miRNAs with optimal predictive performance. Finally, the peripheral serum miRNAs of 64 LUAD patients and 59 normal individuals were extracted for qRT-PCR analysis to validate the performance of the diagnostic model in respect of clinical detection. Finally, according to area under the curve (AUC) and accuracy values, the NB classifier composed of miR-5100 and miR-663a manifested the most outstanding diagnostic performance. The PCA results also revealed that the 2-miRNA diagnostic signature could effectively distinguish cancer patients from healthy individuals. Finally, qRT-PCR results of clinical serum samples revealed that miR-5100 and miR-663a expression in tumor samples was remarkably higher than that in normal samples. The AUC of the 2-miRNA diagnostic signature was 0.968. In summary, we identified markers (miR-5100 and miR-663a) in serum for early LUAD screening, providing ideas for developing early LUAD diagnostic models.

SNHG15 enhances cisplatin resistance in lung adenocarcinoma by affecting the DNA repair capacity of cancer cells.

BACKGROUND: Lung adenocarcinoma (LUAD) is a prevalent malignancy. SNHG15 has been demonstrated to be oncogenic in many kinds of cancers, however the mechanism of SNHG15 in LUAD cisplatin (DDP) resistance remains unclear. In this study, we demonstrated the effect of SNHG15 on DDP resistance in LUAD and its related mechanism. METHODS: Bioinformatics analysis was adopted to assess SNHG15 expression in LUAD tissues and predict the downstream genes of SNHG15. The binding relationship between SNHG15 and downstream regulatory genes was proved through RNA immunoprecipitation, chromatin immunoprecipitation and dual-luciferase reporter assays. Cell counting kit-8 assay was adopted to evaluate LUAD cell viability, and gene expression was determined by Western blot and quantitative real-time polymerase chain reaction. We then performed comet assay to assess DNA damage. Cell apoptosis was detected by Tunnel assay. Xenograft animal models were created to test the function of SNHG15 in vivo. RESULTS: SNHG15 was up-regulated in LUAD cells. Moreover, SNHG15 was also highly expressed in drug-resistant LUAD cells. Down-regulated SNHG15 strengthened the sensitivity of LUAD cells to DDP and induced DNA damage. SNHG15 could elevate ECE2 expression through binding with E2F1, and it could induce DDP resistance by modulating the E2F1/ECE2 axis. In vivo experiments verified that the SNHG15 could enhance DDP resistance in LUAD tissue. CONCLUSION: The results suggested that SNHG15 could up-regulate ECE2 expression by recruiting E2F1, thereby enhancing the DDP resistance of LUAD.

Identification and validation of a hypoxia-immune signature for overall survival prediction in lung adenocarcinoma.

Objective: The interaction between immunity and hypoxia in tumor microenvironment (TME) has clinical significance, and this study aims to explore immune-hypoxia related biomarkers in LUAD to guide accurate prognosis of patients. Methods: The LUAD gene expression dataset was downloaded from GEO and TCGA databases. The immune-related genes and hypoxia-related genes were acquired from ImmPort and MSigDB databases, respectively. Genes related to immune and hypoxia in LUAD were obtained by intersection. The significantly prognostic genes in LUAD were obtained by LASSO and Cox regression analyses and a prognostic model was constructed. Kaplan-Meier and receiver operating characteristic curves were generated to evaluate and validate model reliability. Single-sample gene set enrichment analysis (ssGSEA) and gene set variation analysis (GSVA) were employed to analyze immune cell infiltration and pathway differences between high- and low-risk groups. Nomogram and calibration curves for survival curve and clinical features were drawn to measure prognostic value of the model. Results: The prognosis model of LUAD was constructed based on seven immune-hypoxia related genes: S100P, S100A16, PGK1, TNFSF11, ARRB1, NCR3, and TSLP. Survival analysis revealed a poor prognosis in high-risk group. ssGSEA result suggested that activities of immune cells in high-risk group was remarkably lower than in low-risk group, and GSVA result showed that immune-related pathway was notably activated in low-risk group. Conclusion: Immune-hypoxia related genes were found to be prognostic biomarkers for LUAD patients, based on which a 7-immune-hypoxia related gene-signature was constructed. This model can assess immune status of LUAD patients, and provide clinical reference for individualized prognosis, treatment and follow-up of LUAD patients.

PAR2 promotes tumor-associated angiogenesis in lung adenocarcinoma through activating EGFR pathway.

BACKGROUND: Metastasis of advanced lung adenocarcinoma (LUAD) is a key cause of cancer-related death, and angiogenesis is the main feature of tumor growth and metastasis. METHODS: The expression level of F2R like trypsin receptor 1(F2RL1) which encodes protease-activated receptor 2 (PAR2) protein in LUAD tissues was analyzed by bioinformatics. The effects of F2RL1 overexpression/silencing on cell proliferation and sphere-forming were analyzed by Cell Counting Kit-8 and colony formation assays, stem cell sphere-forming assay, and angiogenesis assay, respectively. The F2RL1 mRNA expression level and the PAR2 protein expression level, vascular endothelial growth factor A (VEGFA), and epidermal growth factor receptor (EGFR) in lung cancer cell lines were evaluated by real-time quantitative polymerase chain reaction and western blot. The level of VEGFA secreted by lung cancer cells was analyzed by Enzyme-linked immunosorbent assay (ELISA). The effect of F2RL1-mediated EGFR signaling on angiogenesis was further explored by EGFR inhibitor AG1478. RESULTS: F2RL1 was substantially up-regulated in LUAD tissues and cells, and overexpression of F2RL1 could promote proliferation and stem cell sphere-forming of lung cancer cell lines, as well as formation of blood vessels and branch points of human umbilical vein endothelial cells (HUVECs). Meanwhile, overexpression of F2RL1 significantly upregulated VEGFA expression and promoted EGFR phosphorylation. EGFR inhibitor AG1478 treatment significantly down-regulated pEGFR, and AG1478 treatment reversed the promoting effect of cancer cell cultured medium (oe-F2RL1) on HUVEC angiogenesis. SIGNIFICANCE: In summary, this study revealed the molecular mechanism of PAR2 promoting LUAD angiogenesis by activating EGFR signaling pathway, which further improves our understanding of LUAD angiogenesis, and provides a potential therapeutic strategy for LUAD treatment.

Glucose-6-phosphate dehydrogenase promotes the proliferation and migration of lung adenocarcinoma cells via the STAT3 signaling pathway.

Lung adenocarcinoma (LUAD) is the most common histological subtype of lung cancer, and the leading cause of cancer-related deaths worldwide. G6PD has been reported to enhance the progression of various tumors by regulating the intracellular redox state and mediating nucleic acid synthesis. However, the biological role and molecular mechanism of G6PD in LUAD remain largely unknown. In this study, we found that G6PD was significantly upregulated in LUAD specimens and cell lines, and that the high levels of G6PD expression were closely associated with a poor prognosis for LUAD patients. Moreover, we found that G6PD significantly promoted the proliferation and migration of LUAD cells in vitro, and overexpression of G6PD also play a role of facilitating tumorigenesis in in vivo experiments. Mechanistically, the STAT3 signaling pathway was significantly activated by G6PD-mediated LUAD progression. Overall, our results suggest that G6PD could serve as a novel prognostic marker and therapeutic target for treating LUAD.

Erratum: RPL35 promotes neuroblastoma progression via the enhanced aerobic glycolysis.

[This corrects the article on p. 5701 in vol. 11, PMID: 34873488.].

RPL35 promotes neuroblastoma progression via the enhanced aerobic glycolysis.

Neuroblastoma (NB) is an rare type of tumor that almost affects children age 5 or younger due to its rapid proliferation ability. The overall survival rate of patients with advanced NB is not satisfactory. Ribosomal proteins (RPs) play a critical role in the development and progress of cancer. However, the contribution of RPL35 in NB has not been proven. In this study, we reveal that RPL35 is upregulated in NB tissues and the upregulation of RPL35 promotes proliferation and migration of NB while RPL35 knockdown significantly restrained the proliferation of NB cells. In terms of mechanism, glycolysis was decreased and the mitochondrial respiration was increased with knockdown of RPL35 in NB cells, indicating that RPL35 function as a positive regulator in aerobic glycolysis. Importantly, our data indicated that RPL35 deficiency decreased HIF1α expression both in mRNA and protein levels. Western blot analysis showed that RPL35 knockdown has a negative regulatory effect on the ERK pathway, and RPL35 modulated aerobic glycolysis in part through its regulation of the RPL35/ERK/HIF1α axis. Overall, RPL35 functions as a positive regulator of aerobic glycolysis, and the RPL35/ERK/HIF1α axis could be a potential therapeutic target for the therapy of NB.