Differential expression and analysis of extrachromosomal circular DNAs as serum biomarkers in pulmonary arterial hypertension.

BACKGROUND: Extrachromosomal circular DNAs (eccDNAs) have been reported to play a key role in the occurrence and development of various diseases. However, the characterization and role of eccDNAs in pulmonary arterial hypertension (PAH) remain unclear. METHODS: In the discovery cohort, we first explored eccDNA expression profiles by Circle-sequencing analysis. The candidate eccDNAs were validated by routine polymerase chain reaction (PCR), TOPO-TA cloning and Sanger sequencing. In the validation cohort, 30 patients with PAH and 10 healthy controls were recruited for qPCR amplification to detect the candidate eccDNAs. Datas at the baseline were collected, including clinical background, biochemical variables, echocardiography and hemodynamic factors. Receiver operating characteristic curve was used to investigate the diagnostic effect of the eccDNA. RESULTS: We identified a total of 21,741 eccDNAs in plasma samples of 3 IPAH patients and 3 individuals in good health, and the expression frequency, GC content, length distribution, and genome distribution of the eccDNAs were thoroughly characterized and analyzed. In the validation cohort, 687 eccDNAs were differentially expressed in patients with IPAH compared with healthy controls (screening threshold: |FC|≥2 and P < 0.05). Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the specific eccDNAs in IPAH were significantly enriched in calcium channel activity, the mitogen-activated protein kinase pathway, and the wnt signaling pathway. Verification queue found that the expression of eccDNA-chr2:131208878-131,424,362 in PAH was considerably higher than that in healthy controls and exhibited a high level of accuracy in predicting PAH with a sensitivity of 86.67% and a specificity of 90%. Furthermore, correlation analysis disclosed a significant association between serum eccDNA-chr2:131208878-131,424,362 and mean pulmonary artery pressure (mPAP) (r = 0.396, P = 0.03), 6 min walking distance (6MWD) (r = -0.399, P = 0.029), N-terminal pro-B-type natriuretic peptide (NT-proBNP) (r = 0.685, P < 0.001) and cardiac index (CI) (r = - 0.419, P = 0.021). CONCLUSIONS: This is the first study to identify and characterize eccDNAs in patients with PAH. We revealed that serum eccDNA-chr2:131208878-131,424,362 is significantly overexpressed and can be used in the diagnosis of PAH, indicating its potential as a novel non-invasive biomarker.

LncRNA LINC00969 promotes acquired gefitinib resistance by epigenetically suppressing of NLRP3 at transcriptional and posttranscriptional levels to inhibit pyroptosis in lung cancer.

Epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment prolongs the survival of lung cancer patients harbouring activating EGFR mutations. However, resistance to EGFR-TKIs is inevitable after long-term treatment. Molecular mechanistic research is of great importance in combatting resistance. A comprehensive investigation of the molecular mechanisms underlying resistance has important implications for overcoming resistance. An accumulating body of evidence shows that lncRNAs can contribute to tumorigenesis and treatment resistance. By bioinformatics analysis, we found that LINC00969 expression was elevated in lung cancer cells with acquired gefitinib resistance. LINC00969 regulated resistance to gefitinib in vitro and in vivo. Mechanistically, gain of H3K4me1 and H3K27Ac led to the activation of LINC00969 expression. LINC00969 interacts with EZH2 and METTL3, transcriptionally regulates the level of H3K27me3 in the NLRP3 promoter region, and posttranscriptionally modifies the m6A level of NLRP3 in an m6A-YTHDF2-dependent manner, thus epigenetically repressing NLRP3 expression to suppress the activation of the NLRP3/caspase-1/GSDMD-related classical pyroptosis signalling pathways, thereby endowing an antipyroptotic phenotype and promoting TKI resistance in lung cancer. Our findings provide a new mechanism for lncRNA-mediated TKI resistance from the new perspective of pyroptosis via simultaneous regulation of histone methylation and RNA methylation. The pivotal role of LINC00969 gives it the potential to be a novel biomarker and therapeutic target for overcoming EGFR-TKI resistance in lung cancer.

Carbonic Anhydrase IX Controls Vulnerability to Ferroptosis in Gefitinib-Resistant Lung Cancer.

Acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI, such as gefitinib) in lung cancer continues to be a major problem. Recent studies have shown the promise of ferroptosis-inducing therapy in EGFR-TKI resistant cancer, but have not been translated into clinical benefits. Here, we identified carbonic anhydrase IX (CA9) was upregulated in gefitinib-resistant lung cancer. Then we measured the cell viability, intracellular reactive oxygen species (ROS) levels, and labile iron levels after the treatment of ferroptosis inducer erastin. We found that CA9 confers resistance to ferroptosis-inducing drugs. Mechanistically, CA9 is involved in the inhibition of transferrin endocytosis and the stabilization of ferritin, leading to resistance to ferroptosis. Targeting CA9 promotes iron uptake and release, thus triggering gefitinib-resistant cell ferroptosis. Notably, CA9 inhibitor enhances the ferroptosis-inducing effect of cisplatin on gefitinib-resistant cells, thus eliminating resistant cells in heterogeneous tumor tissues. Taken together, CA9-targeting therapy is a promising approach to improve the therapeutic effect of gefitinib-resistant lung cancer by inducing ferroptosis.

Efficacy and safety of antiangiogenic agents or chemotherapy plus EGFR-TKIs in advanced non-small cell lung cancer: A systematic review and network meta-analysis.

BACKGROUND: The combination of antiangiogenic agents with epidermal growth factor receptor inhibitors (EGFR-TKIs) and chemotherapy with EGFR-TKIs are the most common combination treatment options in epidermal growth factor receptor (EGFR) positive non-small cell lung cancer (NSCLC). This network meta-analysis was performed to evaluate the differences between them. METHODS: We searched the PubMed, EMBASE and the Cochrane Controlled Trials Register up to August 2022. The primary outcomes were progression-free survival (PFS) and objective response rate (ORR). The secondary endpoints were overall survival (OS), disease control rate (DCR) and adverse events (AEs). The data of hazard ratio (HR) or risk ratio (RR) with their corresponding 95% confidence intervals (CIs) were extracted in the studies. A network meta-analysis (NMA) was used to indirectly compare the efficacy and safety of antiangiogenic agents plus EGFR-TKIs and chemotherapy plus EGFR-TKIs. RESULTS: Pooled data of included studies were demonstrated that chemotherapy plus EGFR-TKIs had a benefit in ORR compared to antiangiogenic agents plus EGFR-TKIs in patients with EGFR mutated NSCLC (RR = 1.1, 95% CI: 1.0-1.2). However, there were no significant differences in PFS, OS and DCR between in the two group (PFS: HR = 1.0, 95% CI: 0.74-1.6; OS: HR = 0.78, 95% CI: 0.45-1.5; DCR: RR = 1.0, 95% CI: 0.94-1.1). The common treatment-related AEs in the two groups were relatively manageable. CONCLUSION: Based on the efficacy and safety, the combination of chemotherapy with EGFR-TKIs is considered the best combination treatment options in advanced NSCLC with EGFR mutation.

MNX1-AS1 Promotes Phase Separation of IGF2BP1 to Drive c-Myc-Mediated Cell-Cycle Progression and Proliferation in Lung Cancer.

c-Myc and E2F1 play critical roles in many human cancers. As long noncoding RNAs (lncRNA) are known to regulate various tumorigenic processes, elucidation of mechanisms of cross-talk between lncRNAs and c-Myc/E2F1-related signaling pathways could provide important insights into cancer biology. In this study, we used integrated bioinformatic analyses and found that the lncRNA MNX1-AS1 is upregulated in non-small cell lung cancer (NSCLC) via copy-number gain and c-Myc-mediated transcriptional activation. High levels of MNX1-AS1 were associated with poor clinical outcomes in patients with lung cancer. MNX1-AS1 promoted cell proliferation and colony formation in vitro and tumor growth in vivo. MNX1-AS1 bound and drove phase separation of IGF2BP1, which increased the interaction of IGF2BP1 with the 3'-UTR (untranslated region) of c-Myc and E2F1 mRNA to promote their stability. The c-Myc/MNX1-AS1/IGF2BP1 positive feedback loop accelerated cell-cycle progression and promoted continuous proliferation of lung cancer cells. In a lung cancer patient-derived xenograft model, inhibition of MNX1-AS1 suppressed cancer cell proliferation and tumor growth. These findings offer new insights into the regulation and function of c-Myc and E2F1 signaling in NSCLC tumorigenesis and suggest that the MNX1-AS1/IGF2BP1 axis may serve as a potential biomarker and therapeutic target in NSCLC. SIGNIFICANCE: MNX1-AS1 drives phase separation of IGF2BP1 to increase c-Myc and E2F1 signaling and to activate cell-cycle progression to promote proliferation in NSCLC.

Copy number amplification and SP1-activated lncRNA MELTF-AS1 regulates tumorigenesis by driving phase separation of YBX1 to activate ANXA8 in non-small cell lung cancer.

Long non-coding RNAs (lncRNAs) are reported to play key roles in tumorigenesis. However, the mechanisms underlying lncRNA-mediated regulation of RNA-binding protein phase separation in tumorigenesis have not been completely elucidated. In this study, an oncogenic lncRNA MELTF-AS1 was identified using systematic data analysis, screening, and verification. MELTF-AS1 was markedly upregulated in non-small cell lung cancer (NSCLC). High MELTF-AS1 levels were associated with advanced tumor-node-metastasis stage (TNM), high tumor size, and decreased survival time. Functionally, MELTF-AS1 regulated cell proliferation and metastasis in vitro and in vivo. RNA sequencing analysis revealed that MELTF-AS1 knockdown specifically modulated genes associated with cell proliferation, apoptosis, and migration. Mechanistically, at the genome level, copy number amplification promoted MELTF-AS1 expression. At the transcriptional level, the transcription factor SP1 directly activated MELTF-AS1 transcription by binding to its promoter. Furthermore, MELTF-AS1 could directly bind and drive the phase separation of YBX1, which was an RNA-binding protein and involved in tumorigenesis, thus activating ANXA8 transcription and promoting tumorigenesis of NSCLC. Aberrant activation of ANXA8 and promotion of tumorigenesis have been found in a variety of tumors. These novel findings demonstrated the critical role of MELTF-AS1-driven phase separation-mediated transcriptional regulation and provided a potential novel diagnostic and therapeutic target for NSCLC.

Influence of Monocalcium Phosphate on the Properties of Bioactive Magnesium Phosphate Bone Cement for Bone Regeneration.

Bone defects occurring for various reasons can lead to deformities and dysfunctions of the human body. Considering the need for clinical applications, it is essential for bone regeneration to exploit a scaffold with bioactive bone cement. In this study, we fabricated bioactive magnesium phosphate bone cement (BMPC) at room temperature; then, it was set at to °C and 100% humidity for 2 h. The process was as follows: Simulating a clinical environment, magnesium oxide (MgO) was formed by calcining basic magnesium carbonate (Mg2(OH)2CO3). MgO, potassium dihydrogen phosphate (KH2PO4) and carboxymethyl chitosan (C20H37N3O14, CMC) were mixed to form magnesium phosphate bone cement (MPC); then, monocalcium phosphate (Ca(H2PO4)2) was added to neutralize the alkaline product after MPC hydration to fabricate bioactive magnesium phosphate bone cement (BMPC). The influence of the doped content of Ca(H2PO4)2 on the properties of bone cement was discussed. The results showed that Ca(H2PO4)2 and CMC can adjust the setting time of bone cement to between 8 and 25 min. The compressive strength increased first and then decreased. After 48 h without additional pressure, the compressive strength reached the maximum value, which was about 38.6 MPa. Ca(H2PO4)2 and CMC can play a synergistic role in regulating the properties of BMPC. The BMPC was degradable in the simulated body fluid (SBF). The results of the cytotoxicity experiment and laser confocal microscopy experiment indicated that BMPC fabricated at room temperature had better biocompatibility and degradability, which was more consistent with clinical operation requirements. BMPC is a promising orthopedic material and is suitable for repairing bone defects.

High Expression of ACE2 and TMPRSS2 at the Resection Margin Makes Lung Cancer Survivors Susceptible to SARS-CoV-2 With Unfavorable Prognosis.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has rapidly spread worldwide. Systematic analysis of lung cancer survivors at molecular and clinical levels is warranted to understand the disease course and clinical characteristics. METHODS: A single-center, retrospective cohort study was conducted in 65 patients with COVID-19 from Wuhan Huoshenshan Hospital, of which 13 patients were diagnosed with lung cancer. The study was conducted from February 4 to April 11, 2020. RESULTS: During the course of treatment, lung cancer survivors infected with severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) had shorter median time from symptom onset to hospitalization (P = 0.016) and longer clinical symptom remission time (P = 0.020) than non-cancer individuals. No differences were observed among indicators such as time from symptom onset to hospitalization and symptom remission time between medium-term and short-term survivors. The expression of ACE2 (P = 0.013) and TMPRSS2 (P <0.001) was elevated in lung cancer survivors as compared with that in non-cancer individuals. CONCLUSIONS: ACE2 and TMPRSS2 levels were higher at resection margins of lung cancer survivors than those in normal tissues of non-cancerous individuals and may serve as factors responsible for the high susceptibility to COVID-19 among lung cancer survivors. Lung cancer patients diagnosed with COVID-19, including medium-term survivors, have worse outcomes than the general population.

Efficacy and acquired resistance of EGFR-TKI combined with chemotherapy as first-line treatment for Chinese patients with advanced non-small cell lung cancer in a real-world setting.

BACKGROUND: To compare the benefits and explore the cause of acquired resistance of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) and its combination with chemotherapy in advanced non-small-cell lung cancer (NSCLC) patients harboring EGFR mutation in a real-life setting. METHODS: This retrospective analysis included 117 advanced NSCLC patients with EGFR mutation who underwent next-generation sequencing (NGS) prior to treatment. The combination group included 50 patients who received the regimen of EGFR-TKI combined with chemotherapy, while the EGFR-TKI monotherapy group included 67 patients treated with TKI only. The primary endpoint of this study was progression-free survival (PFS); the secondary endpoints were overall survival (OS), response rate, and toxicity. RESULTS: The median PFS was significantly longer in the combination group than in the EGFR-TKI monotherapy group (19.00 months [95% CI, 14.67-23.33] vs. 11.70 months [95% CI, 10.81-12.59], p < 0.001). Subgroup analysis showed a similar trend of results. The median OS was not reached in the combination group and was 38.50 (95% CI, 35.30-41.70) months in the EGFR-TKI monotherapy group (p = 0.586). Patients in the combination group were more likely to experience adverse events, most of which showed the severity of grade 1 or 2. T790M mutation remains the main reason for acquired resistance, and the frequency of T790M mutation was similar between the two groups (p = 0.898). CONCLUSIONS: Compared with EGFR-TKI monotherapy, EGFR-TKI combined with chemotherapy significantly improved PFS in advanced NSCLC patients with EGFR mutation, with acceptable toxicity.

RNA methyltransferase METTL3 induces intrinsic resistance to gefitinib by combining with MET to regulate PI3K/AKT pathway in lung adenocarcinoma.

Clinical research data show that gefitinib greatly improves the progression-free survival of patients, so it is used in advanced non-small cell lung cancer patients with EGFR mutation. However, some patients with EGFR sensitive mutations do not have good effects on initial gefitinib treatment, and this mechanism is rarely studied. METTL3, a part of N6-adenosine-methyltransferase, has been reported to play an important role in a variety of tumours. In this study, we found that METTL3 is up-regulated in gefitinib-resistant tissues compared to gefitinib-sensitive tissues. Cell function experiments have proved that under the treatment of gefitinib, METTL3 knockdown promotes apoptosis and inhibits proliferation of lung cancer cells. Mechanistic studies have shown that METTL3 combines with MET and causes the PI3K/AKT signalling pathway to be manipulated, which affects the sensitivity of lung cancer cells to gefitinib. Therefore, our research shows that METTL3 can be used as a molecular marker to predict the efficacy of EGFR-TKI therapy in patients, and METTL3 may be a potential therapeutic target.

Down-regulated MAC30 expression inhibits breast cancer cell invasion and EMT by suppressing Wnt/ß-catenin and PI3K/Akt signaling pathways.

Breast cancer (BC) is a leading cause of cancer mortality in women worldwide. MAC30/Transmembrane protein 97 (TMEM97) is aberrantly up-regulated in many human carcinoma cells. However, the function of MAC30 in invasion and EMT of BC cells is uncertain. qRT-PCR was used to determine the level of MAC30 in BC tissues and cell lines. si-MAC30 was transfected into BC cells, and the effects of MAC30 silencing on the invasion and EMT were explored by qRT-PCR as well as transwell and western blot assays. Also, we determined the effects of MAC30 silencing on Wnt/ß-catenin and PI3K/Akt signaling pathways by western blot. We found that MAC30 is significantly up-regulated in BC tissues and cell lines. Down-regulation of MAC30 expression efficiently inhibited the invasion of BC cells. Furthermore, the EMT of BC cells was also inhibited by down-regulation of MAC30. Finally, we found that MAC30 knockdown inhibited Akt phosphorylation, ß-catenin, survivin, and cyclin D1 expressions. To our knowledge, this is the first report investigating the effect of MAC30 on invasion and EMT in BC cells by suppressing Wnt/ß-catenin and PI3K/Akt signaling pathways. MAC30 may be a potential therapeutic target for BC.

Neuropeptide Y enhances proliferation and prevents apoptosis in rat bone marrow stromal cells in association with activation of the Wnt/ß-catenin pathway in vitro.

Neuropeptide Y (NPY) exhibits a critical but poorly understood regulatory signaling function and has been shown to promote proliferation, vascularization and migration in several types of cells and tissues. However, little is known about the specific role of NPY in the proliferation and apoptosis of bone marrow stromal cells (also known as bone marrow-derived mesenchymal stem cells, BMSCs), which contain a subpopulation of multipotent skeletal stem cells. Based on BrdU incorporation tests, Cell Counting Kit-8, flow cytometry, quantitative polymerase chain reaction and western blotting, we showed that NPY significantly promoted the proliferation of BMSCs in a concentration-dependent manner, with a maximal effect observed at a concentration of 10-10M for pro-proliferative and 10-12M for anti-apoptotic activities. Furthermore, NPY significantly increased the percentage of cells in S and G2/M phases. In addition, NPY exhibited a protective effect after 24h of serum starvation as illustrated by a reduction in the apoptosis rate, degree of nuclear condensation, and expression of apoptosis markers, including caspase-3, caspase-9 and Bax mRNA expression. NPY also increased the mRNA and protein expression levels of canonical Wnt signaling pathway proteins, including ß-catenin and c-myc, during the induced proliferative and anti-apoptotic processes. However, the proliferative and anti-apoptotic activities of NPY were partially blocked by both PD160170 (1µM) and DKK1 (0.2µg/mL). These compounds also blocked the mRNA and protein expression of ß-catenin, p-GSK-3ß and c-myc. Therefore, the results of the present study demonstrated that NPY exerts a proliferative and protective effect on BMSCs in a dose- and time-dependent manner in vitro, and importantly, these effects may be mediated via its Y1 receptor and involved in activation of the canonical Wnt signaling pathway.