DNMT3A governs tyrosine kinase inhibitors responses through IAPs and in a cell senescence-dependent manner in non-small cell lung cancer.

Patients with non-small cell lung cancer (NSCLC) treated with tyrosine kinase inhibitors (TKIs) inevitably exhibit drug resistance, which diminishes therapeutic effects. Nonetheless, the molecular mechanisms of TKI resistance in NSCLC remain obscure. In this study, data from clinical and TCGA databases revealed an increase in DNMT3A expression, which was correlated with a poor prognosis. Using NSCLC organoid models, we observed that high DNMT3A levels reduced TKI susceptibility of NSCLC cells via upregulating inhibitor of apoptosis proteins (IAPs). Simultaneously, the DNMT3Ahigh subset, which escaped apoptosis, underwent an early senescent-like state in a CDKN1A-dependent manner. Furthermore, the cellular senescence induced by TKIs was observed to be reversible, whereas DNMT3Ahigh cells reacquired their proliferative characteristics in the absence of TKIs, resulting in subsequent tumour recurrence and growth. Notably, the blockade of DNMT3A/IAPs signals enhanced the efficacy of TKIs in DNMT3Ahigh tumour-bearing mice, which represented a promising strategy for the effective treatment of NSCLC.

Cyclooxygenase-2 mediates gefitinib resistance in non-small cell lung cancer through the EGFR/PI3K/AKT axis.

Gefitinib is a potent inhibitor of EGFR and represents the front-line treatment for non-small cell lung cancer (NSCLC) therapeutics. However, NSCLC patients are prone to develop acquired resistance through as yet, undefined mechanisms of resistance. Here, we investigated the role of COX-2 during gefitinib resistance in NSCLC cells and revealed its underlying mechanism(s) of action. We report the upregulation of COX-2 in gefitinib-resistant NSCLC tissues and cells, which is associated with poor prognosis. In vitro assays in NSCLC cells (PC9/GR) showed that COX-2 facilitates gefitinib resistance in NSCLC cells through its effects on P-gp, MRP1, and BCRP, and cancer cell migration and invasion. In vivo, COX-2 silencing could repress tumor growth. We found that the overexpression of COX-2 enhances the transcription of MMP-2, MMP-7, and MMP-9 which mediates PI3K-AKT activation. In summary, we demonstrate that COX-2 mediates the gefitinib resistance of NSCLC cells through its interaction with EGFR and the PI3K-AKT axis. This highlights COX-2 as a novel molecular target for NSCLC.

Comparison among different presentations of venous thromboembolism because of lung cancer.

INTRODUCTION: Venous thromboembolism (VTE) because of lung cancer has been sufficiently studied, nevertheless, little is known regarding the discrepancy of clinical characteristics and predictive factors among different presentations of VTE because of lung cancer. OBJECTIVES: This study was designed to investigate the distinction of clinical characteristics and predictive factors among different presentations of VTE because of lung cancer. METHODS: All patients concomitant lung cancer and VTE were stratified into three groups: pulmonary embolism (PE) group in which patients had sole PE, deep vein thrombosis (DVT) group with sole DVT and concomitance group with both PE and DVT. RESULTS: Concomitance of PE and DVT (28.2 days) mostly occurred at the early stage after the diagnosis of lung cancer, by contrast with DVT (63.6 days) which did at the latest stage, whereas PE (36.7 days) generally developed intermediately in between (P = .02). In a Kaplan-Meier analysis, the cumulative survival rate of DVT group was higher than that of concomitance group, whereas the rate of PE group lied in between. (P = .002) The strongest correlated factors with the development of DVT, PE and concomitance were adenocarcinoma (HR 3.27, P = .003), chemotherapy (HR 2.62, P = .005) and D-Dimer (HR 3.88, P < .001), respectively. The strongest correlated factors with the mortality of DVT, PE and concomitance were comorbidity (HR 2.32, P = .003), metastasis (HR 3.12, P < .001), and metastasis (HR 4.29, P < .001), respectively. CONCLUSION: Concomitance of DVT and PE represents the severest state of lung cancer, the earliest occurrence of VTE, and the worst survival rate, whereas DVT stands for the mildest condition of lung cancer and stablest pattern of VTE.

SPOP promotes SIRT2 degradation and suppresses non-small cell lung cancer cell growth.

SIRT2 is a NAD-dependent deacetylase and inhibition of SIRT2 has a broad anticancer activity. Here we report that SPOP binds to SIRT2 and mediates its degradation by the 26S proteasome, which can be blocked by MG132 treatment. We also found that the levels of SPOP significantly decreased, while the levels of SIRT2 significantly increased in non-small cell lung cancer (NSCLC) cell lines, compared to normal bronchial epithelial cell line and NSCLC specimens, compared to the paired non-tumor lung tissue. Furthermore, SPOP can suppress NSCLC cell growth. Notably, mutations in NSCLC inhibit the abilities of SPOP to degrade SIRT2 and suppress NSCLC cell growth. These results reveal a novel regulation of SIRT2 by SPOP mediated degradation, which is important for the growth of lung tumor cells.

Integrin ß1-mediated acquired gefitinib resistance in non-small cell lung cancer cells occurs via the phosphoinositide 3-kinase-dependent pathway.

The present study aimed to explore the role of integrin ß1 and the relevant signaling pathways in acquired gefitinib resistance in non-small cell lung cancer (NSCLC). The inhibitory effects of gefitinib, with or without LY294002, on cellular proliferation were evaluated by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide assay. Cell cycle progression and apoptosis were analyzed by flow cytometry, while western blotting was used to evaluate the expression of EGFR, phosphorylated (phospho)-EGFR, protein kinase B (Akt), phospho-Akt, extracellular signal-regulated kinase (Erk) and phospho-Erk. The gene expression profiles of PC9 and PC9/G cells were determined by DNA microarray. Integrin ß1 was knocked down in PC9/G cells by transiently transfected short interfering RNA (siRNA). A scrambled siRNA sequence was used as a control. Apoptosis of transfected cells was determined by Annexin V-phycoerythrin-Cy5/propidium iodide staining. Sequencing products were amplified by nested PCR. The resistant index of PC9/G cells to gefitinib was ~138- to 256-fold higher than that of PC9 cells, and this resistance was accompanied by significant increase in integrin ß1 expression in PC9/G cells. Knockdown of integrin ß1 with short hairpin RNA in PC9/G cells markedly inhibited proliferation and enhanced apoptosis in response to gefitinib, restoring the sensitivity of PC9/G cells gefitinib. Phosphoinositide 3-kinase (PI3K)/Akt activation was observed in PC9/G cells in the presence of gefitinib and the sensitivity of PC9/G cells to gefitinib was also able to be restored by PI3K/Akt pathway inhibitor LY294002. Finally, knockdown of integrin ß1 significantly reduced the levels of phospho-Akt. These findings suggest that integrin ß1 signaling via the PI3K/Akt pathway may be a significant mechanism underlying gefitinib resistance, and may potentially present an alternative therapeutic target for the treatment of NSCLC unresponsive to EGFR inhibitors.

Clinicopathological features and epidermal growth factor receptor mutations associated with epithelial-mesenchymal transition in non-small cell lung cancer.

BACKGROUND AND OBJECTIVE: Small molecular inhibitors of the epidermal growth factor receptor (EGFR) have been extensively studied in non-small cell lung cancer (NSCLC) patients. The discovery of molecular biomarkers that identify the subgroups of NSCLC patients benefiting from EGFR tyrosine kinase inhibitor (TKI) has become an important area of investigation. Recent studies have suggested that epithelial-mesenchymal transition (EMT) in tumours decreases the cellular requirements for EGFR signalling pathway, and this may provide a molecular signature to define those NSCLC patients most likely to respond to treatment with targeted EGFR TKI. This research explored the clinicopathological features and EGFR mutations associated with EMT in NSCLC. METHODS: The EMT status in surgically resected specimens from 62 patients with NSCLC was tested by immunohistochemical staining. The frequency of tumour epithelial phenotype was calculated and the strength of the association with clinicopathological features and EGFR genotype was determined by logistic regression. RESULTS: The overall frequency of the epithelial phenotype was 35.48% (22 of 62). Based on univariate analyses, the frequency of the epithelial phenotype (E-cadherin-positive) was greater for EGFR mutants versus wild types (77.78% vs 18.18%; P < 0.0001) and women versus men (54.55% vs 25%; P = 0.02). Multivariate logistic analysis showed that only the EGFR genotype (odds ratio, 0.063; 95% CI: 0.013-0.3; P = 0.0005) was significantly associated with the epithelial phenotype. CONCLUSION: In patients with NSCLC, there is a higher frequency of epithelial markers in patients with EGFR mutation.

[Sensitivity of two cell lines with acquired resistance to gefitinib to several chemotherapeutic drugs].

OBJECTIVE: To explore the sensitivity of tumor cell lines with acquired resistance to gefitinib to several chemotherapeutic drugs and provide preclinical basis of available chemotherapy regimens after failure of molecular targeted therapy. METHODS: Human lung adenocarcinoma cell lines PC9 and PC9/G with acquired resistance to gefitinib were cultured in vitro. The sensitivity to chemotherapeutic drugs and inhibition rate of cell proliferation was determined by MTT assay. Effects of drugs on apoptosis and expression of P-170 were determined by flow cytometry. Difference of gene expression profile between PC9 and PC9/G cells was analyzed by DNA microarray. Western blot was used to test the expression of Akt, phospho-Akt and integrin beta1. RESULTS: The resistance index of PC9/G cells to cisplatin was about 5.4-fold compared with that of PC9 cells. LY294002 may significantly elevate the sensitivity of PC9/G cells to cisplatin (P < 0.05). PC9/G cells were more sensitive to docetaxel than PC9 cells. No significant difference of sensitivity to pemetrexed was found between these two cell lines. Expression level of P-170 in PC9/G cells was lower than that in PC9 cells. In PC9/G cells, the expression of integrin beta1 and DNA healing gene was high and expression of gene during mitosis was low. The level of expression of Akt, phospho-Akt and integrin beta1 in PC9/G cells was higher than that in PC9 cells. CONCLUSION: In PC9/G cells, a cell line with acquired resistance to gefitinib, over-expression of PI3K, integrin and DNA restoration gene and continuous activation of PI3K is found to be correlated with resistance to cisplatin. Docetaxel or pemetrexed is a more reasonable choice than cisplatin for treatment of NSCLC patients who failed to respond to EGFR-TKI.

A preliminary study on the relation between thunderstorms and mortality of in-patients.

BACKGROUND: The aim of this study was to investigate the association between thunderstorms and mortality of in-patients. METHODS: Data for in-patients and deaths in internal medicine departments from four hospitals in Shanghai were collected and grouped according to meteorological conditions. RESULTS: Weekly mortality of in-patients was significantly higher on days with thunderstorms than on fine days. This effect was significant for patients in respiratory, cardiovascular and neurology wards but not in the wards of other specialties.

Set theory in diagnostic reasoning.

BACKGROUND: Regarding diagnostic reasoning, the currently taught Bayesian theory is a form of hypothetical-deduction reasoning. Using set theory, we offer syllogism reasoning instead of hypothetical-deductive reasoning and establish an online diagnostic expert system model based on this diagnostic methodology. METHODS: Concepts of set theory were employed to demonstrate diagnostic reasoning. ASP, Vbscript and Microsoft Access were used to establish the expert system and data of 50 cases from Shanghai pulmonary hospital were put into the program to test its efficiency. CONCLUSION: Diagnostic procedure is type of syllogism rather than hypothetical-deductive reasoning.