Jiexia Zhang

Detection of epidermal growth factor receptor mutations in plasma by mutant-enriched PCR assay for prediction of the response to gefitinib in patients with non-small-cell lung cancer†

The high frequency of epidermal growth factor receptor (EGFR) mutations in tyrosine kinase inhibitor‐responsive non‐small‐cell lung cancer (NSCLC) cases is now well established, highlighting the predictive value of activating EGFR mutations in guiding the clinical use of EGFR‐targeted therapies. However, specimen source and methods for EGFR mutation analysis are limited by tissue availability and technical feasibility in clinical application. Therefore, the current study is designed to establish a blood‐based approach for the assessment of EGFR mutations in NSCLC patients, in particular the advanced stage, and to test its clinical application. Plasma samples were obtained from the enrolled 134 NSCLC patients. The detection rate of the EGFR exon19 deletions and exon21 L858R was 49.3% (66/134) by the blood‐based, mutant‐enriched polymerase chain reaction. In the paired tumor and plasma samples, the detected mutant types of each pair respectively by direct sequencing and mutant‐enriched polymerase chain reaction were concordant in 17 of 18 (94.4%). In the patients treated with gefitinib as a second‐line therapy, those with plasma EGFR mutation have a prolonged median progression‐free survival compared with those with EGFR wild type (7.609 vs. 2.877 months, p = 0.002). On comparing the efficacy of gefitinib with that of docetaxel, it was found that the median progression‐free survival was significantly longer for patients treated with gefitinib than those with docetaxel in those harboring plasma EGFR mutation (7.609 vs. 3.192 months, p = 0.006). These results suggest that the blood‐based EGFR mutations test has the ability to provide a reliable guidance for clinical decision making for the treatment of the advanced NSCLC patients.

IRE1α-TRAF2-ASK1 pathway is involved in CSTMP-induced apoptosis and ER stress in human non-small cell lung cancer A549 cells.

BACKGROUND CSTMP, a Tetramethylpyrazine (TMP) analogue, is designed and synthesized based on the pharmacophores of TMP and resveratrol. Recent studies showed that CSTMP had strong protective effects in endothelial cells apoptosis by its anti-oxidant activity. However, the pharmacological function of CSTMP in cancer have not been elucidated to date. The objective of this study was to investigate the anti-cancer effect of CSTMP against human non-small cell lung cancer (NSCLC) A549 cells and the underlying mechanisms. METHODS The cell proliferation and apoptosis were detected by MTT assay and flow cytometry. Caspases activity was determined spectrophotometricaly at 405nm using a microtiter plate reader. Western blot and real-time PCR was used to assess the protein and mRNA expression. Immunoprecipitation was used to examine the protein-protein interactions. RESULTS CSTMP inhibited the proliferation and induced cell cycle arrest and apoptosis of A549 cells. Caspase3, 8, 9 and PARP-1 activation, and Bax/Bcl-2 ratio analyses demonstrated that the anti-cancer effect of CSTMP in A549 cells was mediated by promoting caspase- and mitochondria-dependent apoptosis. Furthermore, CSTMP induced ER stress in A549 cells as evidenced by elevated levels of GRP78, GRP94, CHOP, IRE1α, TRAF2, p-ASK1 and p-JNK, activation of caspase12 and 4, and enhanced formation of an IRE1α-TRAF2-ASK1 complex. Knockdown of IRE1α by siRNA suppressed activation of IRE1α, TRAF2, p-ASK1 and p-JNK in CSTMP treated A549 cells. In addition, the effects of CSTMP on the formation of an IRE1α-TRAF2-ASK1 complex, caspase- and mitochondria-dependent apoptosis were also reversed by IRE1α siRNA in A549 cells. CONCLUSIONS Collectively, we showed that CSTMP induced apoptosis of A549 cells were through IRE1α-TRAF2-ASK1 complex-mediated ER stress, JNK activation, and mitochondrial dysfunction. These insights on this novel compound CSTMP may provide a novel anti-cancer candidate for the treatment of NSCLC.

NPTX1 is a novel epigenetic regulation gene and associated with prognosis in lung cancer

BACKGROUND CpG island hypermethylation of gene promoters is a well-known mechanism of epigenetic regulation of tumor related-genes and is directly linked to lung carcinogenesis. Alterations in the pattern of methylation of the NPTX1 gene have not yet been studied in detail in human lung cancer. METHODS Methylation-specific PCR (MSP) and bisulfite sequencing PCR (BSP) were used to analyze promoter methylation status, and real-time quantitative reverse transcription-PCR (qRT-PCR) examined mRNA levels. Subsequently, we compared the methylation profile of NPTX1 in samples of neoplastic and non-neoplastic lung tissue taken from the same patients by using quantitative methylation specific PCR (QMSP). RESULTS CpG island hypermethylation in promoter of NPTX1 was confirmed in lung cancer cell lines. A significant increase in NPTX1 methylation was identified in lung cancer specimens compared to adjacent noncancerous tissues and that it was negatively correlated with its mRNA expression. The overall survival time among patients carrying methylated NPTX1 tumors was significantly shorter as compared to those with unmethylated NPTX1 tumors (P = 0.011). Moreover, methylation of NPTX1 gene was found to be an independent prognostic factor for poor overall survival based on multivariate analysis models (p = 0.021), as was age ≥60 years old (p = 0.012) and TNM stage (p < 0.001). CONCLUSIONS These results suggest that NPTX1 hypermethylation and consequent mRNA changes might be an important molecular mechanism in lung cancer. Epigenetic alterations in NPTX1 may serve as potential diagnostic and prognostic biomarkers in lung cancer.

Ski regulates Smads and TAZ signaling to suppress lung cancer progression

Ski, the transforming protein of the avian Sloan‐Kettering retrovirus, displays both pro‐ and anti‐oncogenic activities in human cancer. The mechanisms underlying these conflicting observations have not been fully understood. Herein, we investigated the mechanism underlying the tumor suppressor activity of Ski. To investigate the effect of Ski re‐activation on TGF‐β and Hippo/TAZ pathway, we measured its effect on the endogenous Smad target genes (PAI‐1 and P15INK4B) and TAZ target gene CTGF. The results revealed that Ski exerted its inhibitory activity in TGF‐β1/Smad signaling pathway. Ski inhibited TAZ by increasing their phosphorylation by Lats2 and did not alter the localization of TAZ. Ski inhibited lung cancer growth and invasion. Ski methylation correlated with decreased mRNA expression in human lung cancer cell lines. Thus, Ski inhibited the function of TGF‐β and TAZ through multiple mechanisms in human lung cancer.

RACK1 Forms a Complex with FGFR1 and PKM2 and Stimulates the Growth and Migration of Squamous Lung Cancer Cells

Phosphorylation of Pyruvate Kinase M2 (PKM2) on Tyr105 by fibroblast growth factor receptor 1 (FGFR1) has been shown to promote its nuclear localization as well as cell growth in lung cancer. Better understanding the regulation of this process would benefit the clinical treatment for lung cancer. Here, it has been found that the adaptor protein receptor for activated PKC kinase (RACK1) formed a complex with FGFR1 and PKM2, and activated the FGFR1/PKM2 signaling. Knocking down the expression of RACK1 impaired the phosphorylation on Tyr105 of PKM2 and inhibited the growth and migration of lung cancer cells, while over‐expression of RACK1 in lung cancer cells led to the resistance to Erdafitinib. Moreover, knocking down the expression of RACK1 impaired the tumorigenesis of lung cancer driven by LKB loss and mutated Ras (KrasG12D). Taken together, our study demonstrated the pivotal roles of RACK1 in FGFR1/PKM2 signaling, suggesting FGFR1/RACK1/PKM2 might be a therapeutic target for lung cancer treatment.

Fatal interstitial lung disease associated with icotinib

The most serious, and maybe fatal, yet rare, adverse reaction of gefitinib and erlotinib is drug-associated interstitial lung disease (ILD), which has been often described. However, it has been less well described for icotinib, a similar orally small-molecule tyrosine kinase inhibitor (TKI). The case of a 25-year-old female patient with stage IV lung adenocarcinoma who developed fatal ILD is reported here. She denied chemotherapy, and received palliative treatment with icotinib (125 mg po, three times daily) on March 1, 2013. One month after treatment initiation, the patient complained of continuous dry cough and rapid progressive dyspnea. Forty one days after icotinib treatment, icotinib associated ILD was suspected when the patient became increasingly dyspnoeic despite of treatment of pericardial effusion, left pleural effusion and lower respiratory tract infection, and X-ray computed tomography (CT) of chest revealed multiple effusion shadows and ground-glass opacities in bilateral lungs. Then, icotinib was discontinued and intravenous corticosteroid was started (methylprednisolone 40 mg once daily, about 1 mg per kilogram) respectively. Forty three days after icotinib treatment, the patient died of hypoxic respiratory failure. ILD should be considered as a rare, but often fatal side effect associated with icotinib treatment.

Efficacy of third-line pemetrexed monotherapy versus pemetrexed combination with bevacizumab in patients with advanced EGFR mutation-positive lung adenocarcinoma.

OBJECTIVE The purposes of this study were to observe the effects of different treatment strategies, including third-line pemetrexed alone versus its combination with bevacizumab, in patients with advanced epidermal growth factor receptor (EGFR) mutation-positive lung adenocarcinoma, and to analyze the effects of the different medication orders of first- and second-line drugs on third-line efficacy. PATIENTS AND METHODS One hundred and sixteen cases of patients with EGFR-positive lung adenocarcinoma who had received third-line pemetrexed alone or in combination with bevacizumab between March 2010 and March 2014 at Guangzhou Institute of Respiratory Diseases, the First Affiliated Hospital of Guangzhou Medical University were analyzed retrospectively. Additionally, all the patients were treated with first-line gemcitabine and cisplatin (GP) chemotherapy and second-line EGFR tyrosine kinase inhibitor (TKI) or with first-line EGFR-TKI and second-line GP chemotherapy. RESULTS The median survival of 61 cases with third-line pemetrexed monotherapy was 36.22 months, the median survival time of 55 cases with third-line pemetrexed plus bevacizumab was 38.76 months, and there was a significant difference in survival time between the two groups (P=0.04). Subgroup analysis revealed that among the 55 cases with third-line bevacizumab plus pemetrexed treatment, the median survival of 29 patients with first-line GP and second-line EGFR-TKI was 42.80 months, while the median survival of 26 patients with first-line EGFR-TKI and second-line GP was only 34.46 months; additionally, there was a significant difference in the survival time between the two subgroups (P=0.001). Among 61 cases with third-line pemetrexed treatment, the median survival of 34 patients with first-line GP and second-line EGFR-TKI was 38.72 months, while the median survival of 27 patients with first-line EGFR-TKI and second-line GP was only 32.94 months; the survival time of the two subgroups was significantly different (P=0.001). CONCLUSIONS Regardless of the order of the first- and second-line chemotherapy and TKI therapy, the pemetrexed plus bevacizumab regimen was superior to the pemetrexed monotherapy as the third-line therapy in patients with advanced EGFR-positive lung adenocarcinoma. However, this strategy is worth further investigation in prospective studies.

Detection of Rare Mutations in EGFR-ARMS-PCR-Negative Lung Adenocarcinoma by Sanger Sequencing

Purpose This study aimed to identify potential epidermal growth factor receptor (EGFR) gene mutations in non-small cell lung cancer that went undetected by amplification refractory mutation system-Scorpion real-time PCR (ARMS-PCR). Materials and Methods A total of 200 specimens were obtained from the First Affiliated Hospital of Guangzhou Medical University from August 2014 to August 2015. In total, 100 ARMS-negative and 100 ARMS-positive specimens were evaluated for EGFR gene mutations by Sanger sequencing. The methodology and sensitivity of each method and the outcomes of EGFR-tyrosine kinase inhibitor (TKI) therapy were analyzed. Results Among the 100 ARMS-PCR-positive samples, 90 were positive by Sanger sequencing, while 10 cases were considered negative, because the mutation abundance was less than 10%. Among the 100 negative cases, three were positive for a rare EGFR mutation by Sanger sequencing. In the curative effect analysis of EGFR-TKIs, the progression-free survival (PFS) analysis based on ARMS and Sanger sequencing results showed no difference. However, the PFS of patients with a high abundance of EGFR mutation was 12.4 months [95% confidence interval (CI), 11.6−12.4 months], which was significantly higher than that of patients with a low abundance of mutations detected by Sanger sequencing (95% CI, 10.7−11.3 months) (p<0.001). Conclusion The ARMS method demonstrated higher sensitivity than Sanger sequencing, but was prone to missing mutations due to primer design. Sanger sequencing was able to detect rare EGFR mutations and deemed applicable for confirming EGFR status. A clinical trial evaluating the efficacy of EGFR-TKIs in patients with rare EGFR mutations is needed.

An expression signature model to predict lung adenocarcinoma-specific survival

Background The current TNM staging system plays a central role in lung adenocarcinoma (LUAD) prognosis. However, it may not adequately stratify the risk of tumor recurrence. With the aid of gene expression profiling, we identified 31 lncRNAs whose expressions in tumor tissues could be used as a risk indicator for the guidance of lung cancer therapy. This exploratory analysis may shed new light on identification of potential prognostic factors. Materials and methods A survival prediction scoring model was developed from the data that are publicly available in The Cancer Genome Atlas (TCGA) LUAD RNA Sequencing dataset. Multivariate Cox regression analysis and Kaplan–Meier analysis were performed on a cohort of 254 stage I lung carcinoma patients with survival records. Results Our model indicates that the panels comprising 31 lncRNAs are highly associated with overall survival (OS): 18.9% (95% CI: 10.4%–34.5%) and 89.5% (95% CI: 80.7%–99.2%) for the high- and low-risk group, respectively. The specificity and sensitivity of the model are verified, which show that the area under receiver operating characteristic curve yields 0.881, meaning our model has good accuracy and it is feasible for further applications. Conclusion The 31-lncRNA model might be able to predict OS in patients with LUAD with high accuracy. Its further applications in biomolecular experiments using clinical samples with independent cohorts of patients are needed to verify the results.

Clinical Significance of Plasma Epstein-Barr Virus DNA in Pulmonary Lymphoepithelioma-like Carcinoma (LELC) Patients

Introduction: Primary pulmonary lymphoepithelioma‐like carcinoma (LELC) is a histologically distinctive subtype of NSCLC and an Epstein‐Barr virus (EBV)‐associated epithelial neoplasm. We investigated the clinical significance of plasma concentrations of EBV DNA in patients with pulmonary LELC. Methods: Two independent sets of plasma samples from a total of 429 patients with patients with pulmonary LELC (287 initial and 142 confirmatory) were available for EBV DNA determination. Plasma samples from the patients were subjected to a real‐time quantitative polymerase chain reaction before treatment and 3 months after radical resection. Cutoff points were determined for pretreatment plasma EBV DNA concentration (low <4000 copies/mL versus high ≥4000 copies/mL) on the basis of a measure of heterogeneity with the log‐rank test statistic with respect to overall survival (OS). The Kaplan‐Meier method and Cox regression were used to evaluate the relationship between plasma EBV DNA concentrations and clinical outcome. Among patients with advanced‐stage pulmonary LELC who underwent sequential blood draws, we evaluated the relationship between change in disease status and change in EBV DNA concentrations by using nonparametric tests. Results: High EBV DNA concentration was associated with shorter OS in the initial, confirmatory, and combined data sets (combined data set hazard ratio = 3.67, 95% confidence interval: 2.72–4.38, p < 0.001). These findings persisted after multivariable adjustment. Compared with low EBV DNA concentration, high EBV DNA concentration was associated with shorter OS in patients with any stage of disease. High EBV DNA concentration was also associated with shorter disease‐free survival (DFS) in patients with stage I/II disease. Patients with persistently detectable plasma EBV DNA had significantly poorer OS (p < 0.001) and DFS (p < 0.001) than did patients with undetectable EBV DNA 3 months after radical resection. In patients who underwent sequential evaluation of EBV DNA, an association was identified between an increase in EBV DNA concentration and a poor response to treatment and disease progression of pulmonary LELC. Conclusion: High baseline EBV DNA concentration is an independent poor prognostic marker in patients with pulmonary LELC. These results should be confirmed in larger prospective trials.