Proscillaridin A inhibits lung cancer cell growth and motility through downregulation of the EGFR-Src-associated pathway.

First-generation tyrosine kinase inhibitors (TKIs) have been associated with good responses in non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR)-sensitizing mutations. However, this therapeutic strategy inevitably promotes resistance to TKIs. This study aimed to investigate the functional role and mechanism of proscillaridin A in NSCLC with or without EGFR mutations. Cellular function assays showed that proscillaridin A could inhibit cell proliferation, migration and invasion in vitro independent of EGFR mutation status. Real-time PCR of the human chromosome 17 α-satellite region revealed that proscillaridin A significantly suppressed tumour micrometastasis in vivo. In immunofluorescence experiments, we found that proscillaridin A decreased filopodia length in NSCLC cells. Furthermore, proscillaridin A also downregulated EGFR-Src-mediated cytoskeleton-related pathways, including FAK-paxillin signalling, which has been shown to promote cell filopodia formation by regulating small G-proteins. Therefore, we used the GST-PBD pull-down assay to demonstrate that proscillaridin A could decrease Cdc42 activity. Moreover, survival analyses of 591 lung adenocarcinoma patients from the GEO database indicated that the expression levels of Src and paxillin and the risk score of the gene signature based on these two factors were negatively correlated with overall survival and could be used as independent prognostic factors. In conclusion, we speculate that proscillaridin A inhibits lung cancer cell growth and motility by regulating EGFR-Src-associated pathways.

Peruvoside is a novel Src inhibitor that suppresses NSCLC cell growth and motility by downregulating multiple Src-EGFR-related pathways.

The tyrosine kinase Src plays an essential role in the progression of many cancers and is involved in several epidermal growth factor receptor (EGFR)-mediated signalling pathways. To improve the efficacy of lung cancer treatments, this study aimed to identify novel compounds that can disrupt the Src-EGFR interaction and that are less dependent on EGFR status with wild-type and mutations than other compounds. We used the Src pY419 ELISA as the platform to screen a compound library of more than 400 plant-derived active ingredients and identified peruvoside as a candidate Src-EGFR crosstalk inhibitor. The effects of peruvoside were evaluated by western blotting, cell function assays, combination Index (CI)-isobologram analyses and in vivo experiments. Peruvoside significantly suppressed the phosphorylation of Src, EGFR, and signal transducer and activator of transcription 3 (STAT3) in a dose- and time-dependent manner and somewhat suppressed their protein expression. Cell function assays revealed that peruvoside inhibited the proliferation, invasion, migration, and colony formation of lung cancer cells in vitro and tumour growth in vivo. Furthermore, peruvoside sensitized gefitinib-resistant tumour cells (A549, PC9/gef and H1975) to gefitinib treatment, indicating that peruvoside may exert synergistic effects when used in combination with established therapeutic agents. Our data also demonstrated that the inhibitory effects of peruvoside on lung cancer progression might be attributed to its ability to regulate Src, phosphoinositide 3-kinase (PI3K), c-Jun N-terminal kinase (JNK), Paxillin, p130cas, and EGFR. Our findings suggest that peruvoside suppresses non-small-cell lung carcinoma (NSCLC) malignancy by downregulating multiple Src-related pathways and could serve as a potential base molecule for developing new anticancer drugs and therapeutic strategies for lung cancer.

Paired-like homeodomain 2B contributes to tumour progression and anti-autophagy in human lung cancer.

Paired-like homeodomain transcription factor 2 (PITX2) is well known to play an essential role in normal embryonic development. Emerging evidence suggests that PITX2 may be involved in human tumorigenesis, but the role of PITX2 in tumour progression remains largely unclear. The expression levels of PITX2 in lung cancer cells were determined by qRT-PCR and Western blot analyses. Gain- and loss-of-function experiments were conducted to investigate the biological roles of PITX2 in the phenotype of lung cancer cells. Immunofluorescence staining and transmission electron microscopy were used to observe autophagy. The expression level and clinical significance of PITX2 were determined in a Taiwanese cohort and the Gene Expression Omnibus (GEO) database, respectively. Here, we show that PITX2B is the most abundant isoform of the bicoid homeodomain family in lung cancer cells. The enforced expression of PITX2B promoted lung cancer tumorigenesis and progression in vitro and in vivo. The mechanistic analysis revealed that the nuclear localization of PITX2B is correlated with its oncogenic functions and two important nuclear localization signals. In addition, PITX2B knockdown in lung cancer cells caused a marked increase in autophagy and apoptosis, suggesting that PITX2B plays an important role in lung cancer cell survival. Moreover, a high expression of PITX2B was associated with a poor overall survival (P<0.05) in both Taiwanese non-small-cell lung cancer patients and GEO lung cancer cohorts. These results provide new insight into the contribution of PITX2B to lung cancer progression, implicate PITX2B as an important component of cell survival signals and further establish PITX2B as a therapeutic target for lung cancer treatment.

Pharmacophore-based virtual screening for the identification of the novel Src inhibitor SJG-136 against lung cancer cell growth and motility.

Aberrant elevated Src activity is related to lung cancer growth and metastasis. Therefore, the development of potent small molecule inhibitors to target Src kinase is a potential therapeutic strategy for lung cancer. This study aimed to develop a computational model for the in silico screening of Src inhibitors and then assess the suppressive effect of candidate compounds on cellular functions. A 3D-quantitative structure-activity relationship (QSAR) pharmacophore model consisting of two hydrogen bond acceptors and two hydrophobic regions was constructed by using 28 structurally diverse compounds with IC50 values spanning four orders of magnitude. A National Cancer Institute (NCI) compound dataset was employed for virtual screening by applying the pharmacophore model and molecular docking. Candidate compounds were chosen from the top 20% of scored hits. Among these compounds, the suppressive effects of 30 compounds available in the NCI on Src phosphorylation were validated by using an enzyme-linked immunosorbent assay. Among these compounds, SJG-136, a pyrrolobenzodiazepine dimer, showed a significant inhibitory effect against Src activity in a dose-dependent manner. Further investigations showed that SJG-136 can inhibit lung cancer cell proliferation, clonogenicity, invasion and migration in vitro and tumour growth in vivo. Furthermore, SJG-136 also had an inhibitory effect on Src-related signaling pathways, including the FAK, paxillin, p130Cas, PI3K, AKT, and MEK pathways. In conclusion, we have established a pharmacophore-based virtual screening approach to identify novel Src inhibitors that can inhibit lung cancer cell growth and motility through suppressing Src-related pathways. These findings may contribute to the development of targeted drugs for lung cancer treatment, such as lead compounds.

Increased risk of community-acquired pneumonia in COPD patients with comorbid cardiovascular disease.

BACKGROUND AND OBJECTIVE: COPD patients with community-acquired pneumonia (CAP) have worse clinical outcomes, as compared to those without COPD. Cardiovascular disease (CVD) is a common comorbidity for COPD patients. Whether COPD with comorbid CVD will increase the risk of CAP is not well investigated. The incidence and factors associated with CAP in COPD patients with and without CVD were analyzed. METHODS: The medical records of patients with newly diagnosed COPD between 2007 and 2010 were reviewed. The patients' characteristics, medical history of CVD, occurrence of CAP, and type of medication were recorded. Kaplan-Meier curves were used to assess the differences in cumulative incidence of CAP. Cox's proportional hazards regression model was used to determine the adjusted hazard ratios with 95% confidence intervals in relation to factors associated with CAP in COPD patients with and without CVD. RESULTS: Among 2,440 patients, 475 patients (19.5%) developed CAP during the follow-up period. COPD patients who developed CAP were significantly older, had lower forced expiratory volume in 1 second, frequent severe exacerbation and comorbid CVD, as well as received inhaled corticosteroid (ICS)-containing therapy than those without CAP. The cumulative incidence of CAP was higher in COPD patients with CVD compared to those without CVD. Patients who received ICS-containing therapy had significantly increased risk of developing CAP compared to those who did not. CONCLUSION: For patients with COPD, comorbid CVD is an independent risk factor for developing CAP. ICS-containing therapy may increase the risk of CAP among COPD patients.

Oncogenic miR-137 contributes to cisplatin resistance via repressing CASP3 in lung adenocarcinoma.

Although targeted therapy can prolong the survival of non-small cell lung cancer (NSCLC) patients with EGFR mutations, chemotherapy still is the choice for patients with wild-type EGFR or failure in targeted therapy. However, most of the patients will eventually develop chemoresistance. Our previous study showed that miR-137 is a risky microRNA and is associated with poor prognosis in NSCLC patients. Here we investigated the role of miR-137 in cisplatin resistance in lung adenocarcinoma patients. Our data indicated that miR-137 overexpression increases the survival of lung cancer cells exposed to cisplatin and decreases cisplatin-induced apoptosis. Through computational prediction and microarray, we identified caspase-3 (CASP3) as a potential target of miR-137. Luciferase reporter and site-directed mutagenesis assays demonstrated that miR-137 downregulates CASP3 through binding to its 3'-UTR. Moreover, the endogenous CASP3 can be modulated by overexpressing or silencing miR-137 in lung adenocarcinoma cell lines regardless of EGFR status. Suppression of CASP3 by miR-137 provides cancer cells with anti-apoptotic ability, leading to cisplatin resistance. Immunohistochemistry results revealed an inverse correlation between miR-137 and CASP3 expressions in lung adenocarcinoma patients. Together, our data provide a new chemoresistance mechanism in lung adenocarcinoma and a possible target to control chemoresistance in lung adenocarcinoma patients.

Tumour suppressor HLJ1: A potential diagnostic, preventive and therapeutic target in non-small cell lung cancer.

Lung cancer is the leading cause of cancer-related mortality throughout the world. Non-small cell lung cancer (NSCLC) accounts for 85% of all diagnosed lung cancers. Despite considerable progress in the diagnosis and treatment of the disease, the overall 5-year survival rate of NSCLC patients remains lower than 15%. The most common causes of death in lung cancer patients are treatment failure and metastasis. Therefore, developing novel strategies that target both tumour growth and metastasis is an important and urgent mission for the next generation of anticancer therapy research. Heat shock proteins (HSPs), which are involved in the fundamental defence mechanism for maintaining cellular viability, are markedly activated during environmental or pathogenic stress. HSPs facilitate rapid cell division, metastasis, and the evasion of apoptosis in cancer development. These proteins are essential players in the development of cancer and are prime therapeutic targets. In this review, we focus on the current understanding of the molecular mechanisms responsible for HLJ1's role in lung cancer carcinogenesis and progression. HLJ1, a member of the human HSP 40 family, has been characterised as a tumour suppressor. Research studies have also reported that HLJ1 shows promising dual anticancer effects, inhibiting both tumour growth and metastasis in NSCLC. The accumulated evidence suggests that HLJ1 is a potential biomarker and treatment target for NSCLC.

Prior EGFR tyrosine-kinase inhibitor therapy did not influence the efficacy of subsequent pemetrexed plus platinum in advanced chemonaïve patients with EGFR-mutant lung adenocarcinoma.

BACKGROUND: Tumor cells before and after epidermal growth-factor receptor (EGFR) tyrosine-kinase inhibitor (TKI) therapy might display different characteristics. The aim of this study was to evaluate the influence of prior EGFR TKI therapy on the efficacy of subsequent pemetrexed plus platinum (PP) in advanced chemonaïve patients with EGFR-mutant lung adenocarcinoma. MATERIALS AND METHODS: Advanced chemonaïve patients with EGFR-mutant lung adenocarcinoma receiving PP as first-line chemotherapy were enrolled retrospectively in two medical centers of Taiwan. The objective of this study was to compare objective response rate (ORR), disease-control rates (DCR), progression-free survival (PFS), and overall survival (OS) of PP in patients with and without prior EGFR TKI therapy. RESULTS: In total, 105 patients were analyzed. Sixty-one patients (58.1%) had prior EGFR TKI therapy and used PP as second-line treatment. The other 44 patients (41.9%) received PP as first-line therapy. ORRs of PP in patients with and without prior EGFR TKI therapy were 24.6% and 38.6%, respectively (P=0.138). DCRs of the two groups were 62.3% and 65.9%, respectively (P=0.837). The median PFS (6.1 versus 6.1 months, P=0.639) and OS (34.4 versus 32.3 months, P=0.394) were comparable between the groups with and without prior EGFR TKI therapy. In a subgroup analysis of patients with prior EGFR TKI therapy, there was no significant association between the efficacy of first-line EGFR TKI and the outcome of subsequent PP therapy. CONCLUSION: Our results suggested that prior EGFR TKI therapy would not influence the efficacy of subsequent PP therapy in advanced chemonaïve patients with EGFR-mutant lung adenocarcinoma.

Mechanical stretch induces endothelial nitric oxide synthase gene expression in neonatal rat cardiomyocytes.

1. Mechanical stretch leads to cardiac hypertrophy and may ultimately cause heart failure. However, the effect of mechanical stretch on gene induction in cardiomyocytes remains to be determined. 2. In the present study, we compared transcript profiles of mechanically stretched neonatal rat cardiomyocytes with those of unstretched cells using cDNA microarrays. The microarrays contained probes for 480 known genes, including those involved in signal transduction, cell cycle regulation, the cytoskeleton and cell motility. Eighteen genes, including the eNOS gene, were identified as having significantly differential expression in response to mechanical stretch in cardiomyocytes. 3. Northern and western blot analysis further quantified the expression of the eNOS gene. Mechanical stretch increased constitutive NOS activity and nitric oxide (NO) production. The NO donor s-nitroso-N-acetylpenicillamine (SNAP) inhibited mechanical stretch-stimulated protein synthesis, as measured by [3H]-leucine uptake. In addition, cardiomyocytes were infected with adenoviral vectors encoding cDNA for eNOS (Ad-eNOS) and a phosphoglycerate kinase (PGK) empty vector (Ad-PGK). In contrast with Ad-PGK-infected cells, in cardiomyocytes infected with Ad-eNOS, there was increased calcium-dependent NOS activity and nitrite production. Cardiomyocytes infected with Ad-eNOS exhibited diminished mechanical stretch-stimulated protein synthesis. In contrast, in eNOS-knockdown cells, the increased eNOS protein levels and NOS activity induced by mechanical stretch were abolished, but protein synthesis was enhanced. 4. The results of the present study indicate that eNOS gene expression is induced by mechanical stretch, leading to increased constitutive NOS activity and NO production, which may be a negative regulator in cardiomyocyte hypertrophy.