Xueqin Yang

Comparison of first-line chemotherapy based on irinotecan or other drugs to treat non-small cell lung cancer in stage IIIB/IV: a systematic review and meta-analysis.

BackgroundTo compare the efficacy and toxicity of irinotecan-based chemotherapy (IBC) and non-irinotecan-based chemotherapy (NIBC) as first-line treatment for stage IIIB/IV non-small cell lung cancer (NSCLC).MethodsPubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), abstracts from the annual meetings of ASCO and the ESMO up to 2014 were searched for randomized controlled trials (RCTs) that compared IBC with NIBC. Data on overall survival (OS) and progression-free survival (PFS) were meta-analyzed to provide hazard ratios (HRs), while data on overall response rate (ORR) and frequencies of toxicity were meta-analyzed to provide relative risk ratios (RR).ResultsSeven RCTs (6 RCTs from Asian population and 1 from non-Asian population) involving 1473 patients with previously untreated stage IIIB/IV NSCLC were included in the meta-analysis. IBC and NIBC were associated with similar ORR (RR: 1.08, 95 %CI: 0.94 to 1.23, p = 0.30), OS (HR: 0.97, 95 %CI: 0.88 to 1.07, p = 0.56), and PFS (HR: 1.02, 95 %CI: 0.97 to 1.08, p = 0.38). However, the subgroups between Asian and non-Asian patients differed significantly in OS (HR: 0.94 vs 1.87, p = 0.007). There was no significant difference for hematological toxicity (RR: 0.79, 95 %CI: 0.60 to 1.04, p = 0.09) and significant worse for non-hematological toxicity (RR: 2.28, 95 %CI: 1.60 to3.24, p < 0.001), when IBC compared to NIBC.ConclusionsAs the available evidence suggests that IBC and NIBC are equivalent in terms of ORR, PFS, OS, at least in Asian patients, we recommend that IBC be considered as a first-line treatment in Asian patients with stage IIIB/IV NSCLC. However, the non-hematological toxicity of IBC must be considered.

APE1 promotes antioxidant capacity by regulating Nrf-2 function through a redox-dependent mechanism.

APE1 is a multifunctional protein that has recently been implicated in protecting cells from oxidative stress. In the current study, we confirmed that APE1׳s effect on cellular antioxidant capacity is related to its redox activity through the use of an APE1 functional mutant, and we investigated the mechanism through which this multifunctional protein affects the function of the transcription factor Nrf-2 in regulating oxidative stress-induced genes. Using a pair of mutants for both the redox activity and the acetylation-regulated activity of APE1, in vitro assays showed that the redox activity of APE1 is crucial for its nuclear association with Nrf-2 and subsequent activation of Nrf-2׳s transcription of several downstream genes during oxidative challenge. Important oxidative stress genes are affected by APE1 redox activity, including Hmox1, Gstm1, and Txnrd1. In addition, utilizing human non-small-cell lung cancer sample tissue as well as a nude mouse xenograft model, we determined that APE1 expression levels are inversely correlated to oxidative stress in vivo. These findings indicated that interference with these crucial functions of APE1 shows promise in preventing resistance to certain radiotherapies and that further research is necessary to understand APE1׳s complex roles in regulating both the basal redox status and the oxidative stress state of the cellular environment.

The N-terminal kinase suppressor of Ras complex has a weak nucleoside diphosphate kinase activity

Introduction:  An increasing number of studies have proven that the kinase suppressor of Ras (KSR1) functions as a scaffolding protein that coordinates the assembly of a multiprotein complex containing mitogen‐activated protein kinase and its upstream regulators. However, a few studies have reported that KSR1 can activate c‐Raf‐1. Therefore, whether KSR1 possesses a kinase activity has been an unresolved issue until now.

LDA-SVM-based EGFR mutation model for NSCLC brain metastases: an observational study.

AbstractEpidermal growth factor receptor (EGFR) activating mutations are a predictor of tyrosine kinase inhibitor effectiveness in the treatment of non–small-cell lung cancer (NSCLC). The objective of this study is to build a model for predicting the EGFR mutation status of brain metastasis in patients with NSCLC.Observation and model set-up.This study was conducted between January 2003 and December 2011 in 6 medical centers in Southwest China.The study included 31 NSCLC patients with brain metastases.Eligibility requirements were histological proof of NSCLC, as well as sufficient quantity of paraffin-embedded lung and brain metastases specimens for EGFR mutation detection. The linear discriminant analysis (LDA) method was used for analyzing the dimensional reduction of clinical features, and a support vector machine (SVM) algorithm was employed to generate an EGFR mutation model for NSCLC brain metastases. Training-testing-validation (3 : 1 : 1) processes were applied to find the best fit in 12 patients (validation test set) with NSCLC and brain metastases treated with a tyrosine kinase inhibitor and whole-brain radiotherapy.Primary and secondary outcome measures: EGFR mutation analysis in patients with NSCLC and brain metastases and the development of a LDA-SVM-based EGFR mutation model for NSCLC brain metastases patients.EGFR mutation discordance between the primary lung tumor and brain metastases was found in 5 patients. Using LDA, 13 clinical features were transformed into 9 characteristics, and 3 were selected as primary vectors. The EGFR mutation model constructed with SVM algorithms had an accuracy, sensitivity, and specificity for determining the mutation status of brain metastases of 0.879, 0.886, and 0.875, respectively. Furthermore, the replicability of our model was confirmed by testing 100 random combinations of input values.The LDA-SVM-based model developed in this study could predict the EGFR status of brain metastases in this small cohort of patients with NSCLC. Further studies with larger cohorts should be carried out to validate our findings in the clinical setting.

Nm23-H1 is involved in the repair of ionizing radiation-induced DNA double-strand breaks in the A549 lung cancer cell line

BackgroundAlthough originally identified as a putative metastasis suppressor, increasing studies have confirmed a possible role for Nm23-H1 in DNA repair, through the base excision repair and nucleotide excision repair pathways. In this study, we explored whether Nm23-H1 was also involved in double-strand break repair (DSBR).Methods and resultsWe constructed a stable A549-shNm23-H1 cell line with doxycycline-regulated expression of Nm23-H1, and a A549-nNm23-H1 cell line that over expressed a nucleus-localized version of Nm23-H1. Results from both lines confirmed that Nm23-H1 participated in the repair of double-strand breaks induced by X-rays, using Comet and γ-H2AX foci assays. Subsequent studies showed that Nm23-H1 activated the phosphorylation of checkpoint-related proteins including ATM serine/threonine kinase (on S1981), tumor protein p53 (on S15), and checkpoint kinase 2 (Chk2) (on T68). We also detected interactions between Nm23-H1 and the MRE11-RAD50-NBS1 (MRN) complex, as well as Ku80. Moreover, NBS1 and Ku80 levels were comparably higher in Nm23-H1 overexpressing cells than in control cells (t = 14.462, p < 0.001 and t = 5.347, p = 0.006, respectively). As Ku80 is the keystone of the non-homologous end joining (NHEJ) pathway, we speculate that Nm23-H1 promotes DSBR through NHEJ.ConclusionsThe results indicate that Nm23-H1 participates in multiple steps of DSBR.

Lung reexpansion of obstructive atelectasis caused by radiotherapy after continuous gefitinib treatment in nonsmall cell lung cancer.

A 75-year-old male was diagnosed with central squamous cell carcinoma of the left lung, who has been given 3-dimensional conformal radiotherapy of total dose with 60 Gy in 30 fractions. Three years later, the tumor relapsed in situ and he received another stereotactic radiotherapy with a total dose of 40 Gy at a margin of planning target volume (PTV) in 10 (5 fractions/week) at 4 Gy/fraction. Gefitinib (250 mg/day) was initiated immediately after radiotherapy. Obstructive atelectasis in the left lung and increased pleural effusion occurred at the fourth month after radiotherapy. As this patient has been detected with deletion in exon 19 of the EGFR gene, gefitinib was continuous administered without interruption. After another 4 months, the atelectasis in the left lung reexpanded significantly. To the best of our knowledge, this is the first report in the literature that EGFR tyrosine kinase inhibitors (EGFR-TKI) reversed the radiation atelectasis of pulmonary in the nonsmall cell lung cancer (NSCLC) patient.

[Construction, Expression and Purification of Wild and Mutant Type of nm23-H1 in Prokaryotic Expression System.].

BACKGROUND Nm23-H1 is a metastasis-suppressor gene. However, its molecular mechanism of suppressing metastasis is unknown until now. The aim of this study is to construct prokaryotic expression vector of wild and mutant type of nm23-H1 (WT, P96S, H118F), and then express and purify the proteins. METHODS wild and mutant type of nm23-H1 fragments were amplified by PCR. The prokaryotic expression vectors of pET28anm23-H1 were constructed by gene recombination technique and verified by restriction enzyme analysis and sequencing. The positive clones were transformed into E. coli BL21 (DE3) and soluble analysis of the expression was conducted in this system. The proteins were purified by nickel column chromatography and identified by Western blot RESULTS The sequences and open read frames of all the pET28a-nm23-H1 plasmids were completely correct. After transforming, these plasmids can express the target proteins. The protein production was very high, and all the proteins were soluble expression. The molecular weight of wild and mutant type of nm23-H1 was 20 kDa detected by Western blot, which was as the same as the objective protein. CONCLUSIONS We have succeeded in constructing the prokaryotic expression vectors of pET28a-nm23-H1 (WT, P96S, H118F) and the proteins which expressed can be used in following studies.

[The mechanism of metastasis suppressor gene nm23-H1 involving in the Ras signaling of lung cancer.].

BACKGROUND It has been confirmed that nm23-H1 gene is one of the tumor metastasis suppressor genes. Up to now, the exact mechanism of nm23-H1 gebe is uncertain. The aim of this study the mechanism of metastasis suppressor gene nm23-H1 involving in the Ras signaling of lung cancer. METHODS The wild and mutant type of pEGFP-nm23-H1 plasmids [WT (wild type), H118F, S120G, P96S, S44A] were transfected into the L9981 lung cancer cell lines through liposome method, and the complex of KSR and nm23-H1 was detected through co-immunoprecipitation and Western blot assay. RESULTS The human KSR could be detected in the nm23-H1 immunoprecipitations in all the trasfected L9981 lung cancer cell lines. But no significant difference of KSR expression was found in the wild and mutant nm23-H1 trasfected cell lines (F =0.190, P =0.938). CONCLUSIONS There was a close interaction between nm23-H1 and KSR, which was independent of the nm23-H1 mutation. Nm23-H1 involving in the Ras signaling of lung cancer may be through the KSR gene.

Construction, expression and purification of kinase suppressor of Ras, KSR

BACKGROUND Ras to MAPK pathway plays a critical role in the transmission of many growth and developmental signals. A new component of this pathway which is termed kinase suppressor of Ras (KSR) was found in 1995. KSR is as a scaffolding protein that coordinates the assembly of a multiprotein complex containing mitogen-activated protein kinase (MAPK) and its upstream regulators. It has been proven that KSR has many phosphorylation sites, and phosphorylation state changes response to signaling events. Site-directed mutagenesis can precisely change the base sequence and get mutant proteins. The aim of this study is to construct two mutant proteins of KSR by using site-directed mutagenesis, and to express and purify them, therefore to provide basement for studying the functional and biochemical mechanisms of KSR. METHODS Site-directed mutagenesis of pCMV-Tag2b-KSR gene was performed by modified QuikChangtm site-directed mutagenesis kit method. Two pairs of mutagenic primers were synthesized in vitro and two mutations desired, the recombinant plasmids were verified by restriction enzyme analysis and DNA sequencing. Then positive clones were transfected into 293T cell line. The purified mutant proteins were analyzed by Western blot. RESULTS Two mutants were successfully constructed. The results of DNA sequencing confirmed that the base sequences of the mutant genes were completely concordant with experiment design, which could be used to be transfected into 293T cell line. The purified mutants were identified by Western blot. CONCLUSIONS Two mutant KSR genes are successfully constructed. It provides experimental basement for further functional research of KSR.