Xiaoxia Chen

MiR-21 overexpression is associated with acquired resistance of EGFR-TKI in non-small cell lung cancer

BACKGROUND AND PURPOSE With the increasing use of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) in patients with advanced non-small cell lung cancer (NSCLC), its acquired resistance has become a major clinical problem. Recent studies revealed that miR-21 was involved into the resistance of cytotoxic agents. The aim of this study was to investigate its role in the acquired resistance of NSCLC to EGFR-TKI. METHODS EGFR-TKI-sensitive human lung adenocarcinoma cell line PC9 and the acquired resistant cell line, PC9R, were used. Lentiviral vectors were used to infect PC9 or PC9R to regulate the miR-21 expression. The expression of targeted proteins PTEN and PDCD4 was controlled by RNA interference. MicroRNA array, RT-PCR and TaqMan MicroRNA Assays were used to detect miR-21 expression. The MTT and Annexin V assays were used to determine proliferation and apoptosis. Western Blot and immunohistochemistry were used to analyze target protein expression (PTEN, PDCD4, Akt, p-Akt). We also constructed PC9R xenograft tumor model to observe the relationship between miR-21 and EGFR-TKI resistance in vivo and validated it in the clinical serum specimens of NSCLC patients treated with EGFR-TKI. RESULT MiR-21 was overexpressed in the EGFR-TKI resistant cell line PC9R relative to PC9. The level of miR-21 was reversely correlated with the expression of PTEN and PDCD4 and positive correlated with PI3K/Akt pathway. Inhibiting miR-21 with lentivirus vector induces apoptosis in PC9R cell line and inhibiting miR-21with ASO suppressed tumor growth in nude mice treated with EGFR-TKI. Furthermore, serum miR-21 expression in NSCLC patients treated with EGFR-TKI was significantly higher at the time of acquiring resistance than at baseline (p<0.01). CONCLUSION miR-21 is involved in acquired resistance of EGFR-TKI in NSCLC, which is mediated by down-regulating PTEN and PDCD4 and activating PI3K/Akt pathway.

Association of EGFR mutation or ALK rearrangement with expression of DNA repair and synthesis genes in never-smoker women with pulmonary adenocarcinoma

Epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) rearrangement may predict the outcome of targeted drug therapy and also are associated with the efficacy of chemotherapy in patients with nonsmall cell lung cancer (NSCLC). The authors of this report investigated the relation of EGFR mutation or ALK rearrangement status and the expression of DNA repair or synthesis genes, including excision repair cross‐complementing 1 (ERCC1), ribonucleotide reductase subunit M1 (RRM1), thymidylate synthetase (TS), and breast cancer‐early onset (BRCA1), as a potential explanation for these observations.

T790M mutation is associated with better efficacy of treatment beyond progression with EGFR-TKI in advanced NSCLC patients

BACKGROUND AND PURPOSE Continuous EGFR-TKI treatment beyond progression has shown promising benefit for some patients with acquired resistance to EGFR-TKIs. The aim of this study was to investigate the association of secondary T790M mutation at the time of progression with the efficacy of EGFR-TKI treatment beyond progression. METHODS From March 2011 to March 2013, patients with advanced NSCLC who developed acquired resistance to EGFR-TKI and where a re-biopsy was performed at Tongji University Cancer Institute were included into this study. Scorpion ARMS was used to detect EGFR mutation status. RESULTS A total of 54 patients were enrolled in this study with a median progression-free survival time (PFS1) of 10.9 months according to RECIST criteria. In all, 53.7% (29/54) had T790M mutation after the failure of EGFR-TKIs; PFS1 was not statistically significantly different between patients with T790M mutation and without (13.0 vs. 10.5 months, p = 0.894). In all, 41 patients received TKI treatment beyond progression, including 22 with local progression to receive additional local therapy and 19 with gradual progression to receive additional chemotherapy. The median progression-free survival time (PFS2) of patients who received EGFR-TKI beyond progression treatment was 3.5 months (95% CI, 2.689-4.311). Patients with T790M mutation had significantly longer PFS2 (6.3 vs. 2.6 months, p = 0.002) and overall survival (39.8 vs. 23.2 months, p = 0.044) than those without. CONCLUSION Patients with secondary T790M mutation at the time of progression having gradual or local progression after acquired resistance to EGFR-TKI benefit more from EGFR-TKI treatment beyond progression compared to those without T790M mutation.

Microarray expression profile of long non-coding RNAs in EGFR-TKIs resistance of human non-small cell lung cancer

The application of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) is limited by drug resistance in non-small cell lung cancer (NSCLC). Long non-coding RNAs (lncRNAs) are known to be involved in tumor development and metastasis, as well as chemotherapy resistance. To gain insight into the molecular mechanisms of EGFR-TKIs resistance, EGFR-TKIs‑sensitive and ‑resistant human lung cancer cells were analyzed by lncRNA microarray. In the present study, we found a total of 22,587 lncRNAs expressed in lung cancer cells. Of these, the expression level of 1,731 lncRNAs was upregulated >2-fold compared with gefitinib-sensitive cells while that of 2,936 was downregulated. Bioinformatics analysis (GO and pathway analyses) revealed that some classical pathways participating in cell proliferation and apoptosis were aberrantly expressed in these cells (P-value cut-off was 0.05). Enhancer-like lncRNAs and their nearby coding genes were analyzed. Six lncRNAs were identified as potential enhancers. Several lncRNAs were validated in lung cancer cell lines using RT-qPCR. To the best of our knowledge, the results showed for the first time that differentially expressed lncRNAs responded to EGFR-TKIs resistance in NSCLC cells. LncRNAs may therefore be novel candidate biomarkers and potential targets for EGFR-TKIs therapy in the future.

Peripheral blood for epidermal growth factor receptor mutation detection in non-small cell lung cancer patients.

OBJECTIVE: It is important to analyze and track Epidermal Growth Factor Receptor (EGFR) mutation status for predicting efficacy and monitoring resistance throughout EGFR-tyrosine kinase inhibitors (TKIs) treatment in non-small cell lung cancer (NSCLC) patients. The objective of this study was to determine the feasibility and predictive utility of EGFR mutation detection in peripheral blood. METHODS: Plasma, serum and tumor tissue samples from 164 NSCLC patients were assessed for EGFR mutations using Amplification Refractory Mutation System (ARMS). RESULTS: Compared with matched tumor tissue, the concordance rate of EGFR mutation status in plasma and serum was 73.6% and 66.3%, respectively. ARMS for EGFR mutation detection in blood showed low sensitivity (plasma, 48.2%; serum, 39.6%) but high specificity (plasma, 95.4%; serum, 95.5%). Treated with EGFR-TKIs, patients with EGFR mutations in blood had significantly higher objective response rate (ORR) and insignificantly longer progression-free survival (PFS) than those without mutations (ORR: plasma, 68.4% versus 38.9%, P = 0.037; serum, 75.0% versus 39.5%, P = 0.017; PFS: plasma, 7.9 months versus 6.1 months, P = 0.953; serum, 7.9 months versus 5.7 months, P = 0.889). In patients with mutant tumors, those without EGFR mutations in blood tended to have prolonged PFS than patients with mutations (19.7 months versus 11.0 months, P = 0.102). CONCLUSIONS: EGFR mutations detected in blood may be highly predictive of identical mutations in corresponding tumor, as well as showing correlations with tumor response and survival benefit from EGFR-TKIs. Therefore, blood for EGFR mutation detection may allow NSCLC patients with unavailable or insufficient tumor tissue the opportunity to benefit from personalized treatment. However, due to the high false negative rate in blood samples, analysis for EGFR mutations in tumor tissue remains the gold standard.

The impact of clinical characteristics on outcomes from maintenance therapy in non-small cell lung cancer: A systematic review with meta-analysis.

OBJECTIVES Although maintenance therapy has been a routine treatment paradigm for advanced non-small cell lung cancer (NSCLC), there is currently lack of direct evidence to identify patients most likely to benefit from maintenance therapy for advanced NSCLC. MATERIALS AND METHODS Trials comparing maintenance therapy with placebo or observation in NSCLC were identified. The primary endpoint was overall survival (OS) in trial population and predefined subgroups. Other endpoints included progression-free survival (PFS) in trial population and predefined subgroups, toxicities and health-related quality of life (QoL). RESULTS 13 trials with 4960 patients were identified. Maintenance therapy yielded a statistically significant but clinically modest improvement in OS (hazard ratio [HR], 0.84; 95% confidence interval [CI], 0.78-0.89, P<0.001), without significant difference between switch and continuation strategy (HR, 0.83 vs. 0.86; Pinteraction=0.631). Patients with performance status (PS) of 0 derived more PFS benefit (HR, 0.52; 95% CI, 0.45-0.61) than those with PS of 1 (HR, 0.69; 95% CI, 0.63-0.76; Pinteraction=0.002). Patients with adenocarcinoma derived more PFS benefit (HR, 0.54; 95% CI, 0.46-0.64) than those with squamous cell carcinoma (HR, 0.85; 95% CI, 0.68-1.06; Pinteraction=0.001). Patients with activating epidermal growth factor receptor (EGFR) mutations derived more survival benefit than those with wild-type EGFR tumors in terms of OS (HR, 0.53 vs. 0.85, Pinteraction=0.086) and PFS (HR, 0.20 vs. 0.80, Pinteraction=0.003). Response to first-line therapy did not significantly predict additional benefit from maintenance therapy. Toxicities occurred more frequently in patients treated with maintenance therapy but health-related QoL was not adversely affected by maintenance therapy. CONCLUSION Maintenance therapy with either a continuation or a switch strategy yields a statistically significant but clinically modest improvement in OS for patients with advanced NSCLC. Factors that may predict benefit from maintenance therapy (tumor histology, PS, or EGFR mutation status), as well as economic considerations should be taken into account before initiating maintenance therapy.

Epithelial phenotype as a predictive marker for response to EGFR-TKIs in non-small cell lung cancer patients with wild-type EGFR.

Epithelial‐to‐mesenchymal transition (EMT) has profound impacts on cancer progression and also on drug resistance, including epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‐TKIs). Nowadays, there is still no predictive biomarker identified for the use of EGFR‐TKIs in non‐small cell lung cancer (NSCLC) patients with wild‐type EGFR. To clarify the role of EMT phenotype as a predictive marker for EGFR‐TKI, we performed a retrospective study in 202 stage IV or recurrent NSCLC patients receiving gefitinib or erlotinib therapy from June 2008 to September 2012 in our institute. Clinical data and EGFR mutational status were collected, while epithelial, epithelial to mesenchymal, not specified or mesenchymal phenotype were classified according to EMT markers such as E‐cadherin, fibronectin, N‐cadherin and vimentin by immunohistochemistry. Epithelial phenotype was more frequently found in patients with EGFR mutation (p = 0.044). Epithelial phenotype was associated with a significantly higher objective response rate (23.5 vs. 11.1 vs. 0.0 vs. 2.4%, p = 0.011), longer progression‐free survival (4.4 vs. 1.9 vs. 1.7 vs. 1.0 months, p < 0.001) and longer overall survival (11.5 vs. 8.9 vs. 4.5 vs. 4.9 months, p < 0.001) compared to epithelial to mesenchymal, not specified and mesenchymal phenotype in the wild‐type EGFR subgroup. In the subgroup with EGFR mutation, the trend remained but without a statistically significant difference. In conclusion, epithelial phenotype was more likely expressed in patients with EGFR mutation and was associated with a better outcome in advanced NSCLC patients with wild‐type EGFR, which indicates that the EMT phenotype might be a potential marker to guide EGFR‐TKI therapy in this population.

Association of XRCC3 and XPD751 SNP with efficacy of platinum-based chemotherapy in advanced NSCLC patients

IntroductionThe aim of this study was to investigate whether X-ray repair cross-complementing group 3 (XRCC3) and xeroderma pigmentosum group D (XPD) single nucleotide polymorphism (SNP) affects the outcome of platinum-based chemotherapy in advanced non-small-cell lung cancer (NSCLC) patients.Material and methodsFrom September 2005 to June 2009, 355 advanced-stage NSCLC patients were accrued to compare the SNP variants with the outcome of platinum-based chemotherapy. TaqMan RT-PCR was used to evaluate the SNPs of the XRCC3 codon241 (Thr/Met) and XPD codon751 (Lys/Gln) DNA repair genes.ResultsThere was a lack of association between the studied SNPs and the response rate, progression-free survival or overall survival (OS) in the whole population. However, subgroup analysis revealed that XRCC3 241 Thr/Met or Met/Met allele was associated with marginally significantly longer OS than XRCC3 Thr/Thr allele (19.0 m vs. 12.5 m, p=0.081) in the patients treated with gemcitabine/cisplatin or carboplatin (GP/GC) while it was correlated with a significantly shorter OS in the patients treated with non GP/GC (9.3 m vs. 16 m, p=0.003). XPD751 Lys/Lys had an association with statistical significantly longer OS than XPD751 Lys/Gln or Gln/Gln in the subgroup of elderly patients (14.10 m vs. 10 m, p=0.019) and patients with non-adenocarcinoma (12.6 m vs. 9 m, p=0.042).ConclusionsXRCC3 Thr241Met played an opposite role in predicting prognosis of chemotherapy in NSCLC patients according to the first-line regimens. XPD 751 Lys/Lys might be a better prognostic marker of elderly or noncarcinoma NSCLC subgroup treated with platinum-based chemotherapy.

A case of lung adenocarcinoma harboring exon 19 EGFR deletion and EML4-ALK fusion gene

We report a man with advanced adenocarcinoma who harboring exon 19 (E746-A750del) epidermal growth factor receptor (EGFR) deletion and echinoderm microtubule-associated protein like 4-anaplastic lymphoma kinase (EML4-ALK) gene translocation in the re-biospy specimen. The patient was treated with erlotinib with a stable disease but progressed slowly, while crizotinib showed a complete response.

Folate Receptor-Positive Circulating Tumor Cell Detected by LT-PCR-Based Method as a Diagnostic Biomarker for Non-Small-Cell Lung Cancer.

Introduction: To investigate the diagnostic performance of folate receptor–positive circulating tumor cells in distinguishing non–small-cell lung cancer (NSCLC) from lung benign disease by using a novel ligand-targeted polymerase chain reaction (PCR) detection technique. Methods: Circulating tumor cells were enriched from 3-ml peripheral blood by immunomagnetic depletion of leukocytes and then labeled with a conjugate of a tumor-specific ligand folic acid and a synthesized oligonucleotide. After washing off free conjugates, the stripped bound conjugates were analyzed by quantitative PCR. Results: Seven hundred fifty-six participants (473 patients with NSCLC, 227 patients with lung benign disease, and 56 healthy donors) were randomly assigned to a training set and a test set. The circulating tumor cell (CTC) levels in patients with NSCLC were significant higher than those with lung benign disease (p < 0.001) and healthy donors (p < 0.001). Compared with carcinoembryonic antigen, neuron-specific enolase, and Cyfra21-1, CTCs displayed the highest area under the receiver operating characteristic curve (training set, 0.815; validation set, 0.813) in the diagnosis of NSCLC, with a markedly sensitivity (training set, 72.46%; validation set, 76.37%) and specificity (training set, 88.65%; validation set, 82.39%). The model combining CTCs with carcinoembryonic antigen, neuron-specific enolase, and Cyfra21-1 was more effective for the diagnosis of NSCLC than tumor makers alone (sensitivity and specificity in the training set, 84.21% and 83.91%; validation set, 88.78% and 87.36%, respectively). In addition, the CTC levels were higher in patients with stage III/IV NSCLC compared with those with stage I/II disease. Conclusion: Ligand-targeted PCR technique was feasible and reliable for detecting folate receptor–positive CTCs in patients with NSCLC, and CTC levels could be used as a useful biomarker for the diagnosis of NSCLC.