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.

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.

Overexpression of miR-100 inhibits cancer growth, migration, and chemosensitivity in human NSCLC cells through fibroblast growth factor receptor 3.

Nonsmall cell lung cancer (NSCLC) is a commonly occurring lung cancer. A combination of molecular biological treatments with regular chemotherapy may result in improved therapeutic outcome. Here, we reported significantly higher levels of fibroblast growth factor receptor 3 (FGFR3) and significantly lower levels of miR-100 in the NSCLC specimen, compared to the paired NSCLC-adjacent normal lung tissues. Moreover, the levels of FGFR3 and miR-100 were inversely correlated. Bioinformatics analyses followed by luciferase reporter assay showed that miR-100 bound to the 3'-UTR of FGFR3 messenger RNA (mRNA) to inhibit its translation. Overexpression of miR-100 in NSCLC cells decreased FGFR3 protein levels, whereas inhibition of miR-100 increased FGFR3 protein levels, without affecting FGFR3 mRNA levels. Furthermore, overexpression of miR-100 suppressed cancer growth, migration, and chemosensitivity in NSCLC cells, while inhibition of miR-100 significantly facilitated them. Taken together, our data demonstrate that miR-100 may inhibit NSCLC through FGFR3.

[Interventional therapy for lung cancer patients with superior vena cava syndrome].

OBJECTIVE: To investigate the method, therapeutic effect and safety of interventional therapy for lung cancer patients with superior vena cava syndrome (SVCS). METHODS: Fifty-two cases of lung cancer with SVCS who received interventional therapy in our hospital between Jan to Dec 2011 were included in this study. Of the 52 cases, 50 cases had successfully carried out superior vena cava stent implantation. The distal venous pressure was measured before and after angioplasty, and the results were assessed by Wilcoxon matched-pairs test. In addition, the 50 patients were followed up and the therapeutic effect and postoperative survival rate were evaluated. RESULTS: The mean distal venous pressure in the 50 patients was significantly decreased from preoperative (28.2 ± 1.9)cm H2O to postoperative (8.7 ± 0.5)cm H2O (P = 0.0085). The efficacy of the treatment was as follows: complete remission (20/52, 38.5%), partial remission (28/52, 53.8%), ineffective 4 (4/52, 7.7%), and total effective rate 92.3%. The complications after angioplasty and stent implantation included chest pain (12 cases, 23.1%), hematoma at the puncture site (5 cases, 9.6%), and fever (2 cases, 3.8%). No serious complications such as massive hemorrhage, pulmonary embolism and stent migration into the cardiac atrium were observed. The rate of postoperative restenosis was low (2/52, 3.8%). For the SCLC group, the objective effective rate was 74.1% and 1-year survival rate was 21.0%. For the NSCLC group, the objective effective rate was 21.7% and 1-year survival rate was 35.0%. CONCLUSIONS: For lung cancer patients with SVCS, interventional therapy may relief obstruction effectively, promote blood flow recovery, and relieve clinical symptoms. Interventional therapy with endovascular angioplasty and stenting may be highly recommended as the first choice for palliative treatment of SVCS. It is an effective initial palliative treatment. However, subsequent comprehensive anti-tumor treatment is necessary.

MicroRNA-214 regulates the acquired resistance to gefitinib via the PTEN/AKT pathway in EGFR-mutant cell lines.

Patients with non-small cell lung cancer (NSCLC) who have activating epidermal growth factor receptor (EGFR) mutations derive clinical benefit from treatment with EGFR-tyrosine kinase inhibitors ((EGFR-TKIs)- namely gefitinib and erlotinib. However, these patients eventually develop resistance to EGFR-TKIs. Despite the fact that this acquired resistance may be the result of a secondary mutation in the EGFR gene, such as T790M or amplification of the MET proto-oncogene, there are other mechanisms which need to be explored. MicroRNAs (miRs) are a class of small non-coding RNAs that play pivotal roles in tumorigenesis, tumor progression and chemo-resistance. In this study, we firstly successfully established a gefitinib resistant cell line-HCC827/GR, by exposing normal HCC827 cells (an NSCLC cell line with a 746E-750A in-frame deletion of EGFR gene) to increasing concentrations of gefitinib. Then, we found that miR-214 was significantly up-regulated in HCC827/ GR. We also showed that miR-214 and PTEN were inversely expressed in HCC827/GR. Knockdown of miR-214 altered the expression of PTEN and p-AKT and re-sensitized HCC827/GR to gefitinib. Taken together, miR-214 may regulate the acquired resistance to gefitinib in HCC827 via PTEN/AKT signaling pathway. Suppression of miR-214 may thus reverse the acquired resistance to EGFR-TKIs therapy.

Individualized Chemotherapy in Advanced NSCLC Patients Based on mRNA Levels of BRCA1 and RRM1.

OBJECTIVE: Experimental evidence suggests that the overexpression of breast cancer-specific tumor suppressor protein 1 (BRCA1) gene enhances sensitivity to docetaxel and resistance to cisplatin and ribonucleotide reductase M1 (RRM1) gene overexpression enhances resistance to gemcitabine. To further examine the effect of BRCA1 and RRM1 mRNA levels on outcome in advanced non-small cell lung cancer (NSCLC), we performed this non-randomized phase II clinical trial which tested the hypothesis that customized therapy would confer improved outcome over non-customized therapy. METHODS: RNA was isolated from fresh tumor tissue. Patients received chemotherapy regimen based on their BRCA1 and RRM1 mRNA levels: both low-cisplatin plus gemcitabine (GP); both high-vinorelbine plus cisplatin (NP); BRCA1 low and RRM1 high-cisplatin plus docetaxel (TP); BRCA1 high and RRM1 low-vinorelbine plus gemcitabine (GN). RESULTS: From Dec 2005 to Nov 2008, 94 metastatic and locally advanced NSCLC patients from our institute were enrolled in this study. The median age was 58 years old. Among them, 21 patients received GP, 30 patients received TP and 43 patients received NP chemotherapy. GP group had a higher response rate, and longer median time to progression (TTP) and median overall survival (OS) time than the other 2 groups. The response rates in the GP, TP and NP groups were 42.9%, 36.7% and 27.9%, respectively (P=0.568). The median TTP was 5.6, 5.0, 4.8 months (P=0.975), respectively, and the median OS time was 12.5, 11.0, 9.7 months (P=0.808), respectively. CONCLUSION: Chemotherapy customized according to BRCA1 and RRM1 expression levels is associated with higher response rate and longer TTP and OS time in the GP group. This suggests that BRCA1 and RRM1 mRNA levels could be used as biomarkers in individual therapy in NSCLC.

[Impact of erlotinib treatment on symptoms and quality of life in patients with advanced non-small-cell lung cancer].

OBJECTIVE: To investigate the impact of erlotinib as a second or third line treatment on the symptoms and quality of life (QOL) in patients with advanced non-small cell lung cancer (NSCLC). METHODS: Fifty patients with stage III b and IV NSCLC, treated previously with at least one regimen of platinum-based chemotherapy, received 150 mg of erlotinib orally, once a day till disease progression. QOL was assessed by European Organization for Research and Treatment of Cancer QLQ-C30 and the lung cancer module (QLQ-LC13). The primary end points for QOL analysis were time to deterioration of three common lung cancer symptoms: cough, dyspnea and pain. RESULTS: Among 47 evaluable cases, there were partial remission (PR) in 18 cases, stable disease (SD) in 21 cases, and progressive disease (PD) in 8 cases. After two cycles of treatment, the mean scores of global QOL and all 5 functioning scales except the cognitive function increased significantly (P < 0.05). Mean scores of major general symptoms, hypodynamia and anorexia, and disease-related symptoms alleviated significantly. Both response rates of five functioning and global QOL were more than 44% after erlotinib treatment. Response rates of major general symptoms and disease-related symptoms varied from 14% to 76%. Patients with complete or partial response likely had improvement in the QOL response (P < 0.05), and the time to major symptom deterioration in those were significantly longer (P < 0.001) than that in patients with stable or even progressive disease. CONCLUSION: Erlotinib is effective to improve not only survival, but also tumor-related symptoms and quality of life in patients with advanced NSCLC previously treated with cisplatin-contained regimens. The improvement in the quality of life is positively correlated with objective tumor response.

[Detection of epidermal growth factor receptor mutations in non-small cell lung cancer by real-time PCR using TaqMan-MGB probes].

OBJECTIVE: To investigate mutations of EGFR TK gene in non-small cell lung cancer (NSCLC) and the diagnostic value of the mutations assayed by real-time PCR using TaqMan-MGB probes. METHODS: Tyrosine kinase genes of EGFR (exons 18, 19 and 21) were amplified by PCR technology, and sequenced and analyzed by Chromas software in 80 NSCLC patients. Based on the results of sequencing, TaqMan-MGB probes were designed and used to detect the mutations of EGFR by real-time PCR. The results of detected mutations were compared between real-time PCR and direct sequencing. The sensitivity and specificity of real-time PCR using TaqMan-MGB probes were analyzed by adding different number of PC-9 cells (exon 19 deleted EGFR) into A549 cells (Wild-type EGFR). RESULTS: Somatic mutations were identified in the tyrosine kinase domain of the EGFR gene in 21 of 80 NSCLC patients with an incidence rate of 26.3%. In-frame deletions of exon 19 occurred in 13 patients and point mutation occurred in codon 858 (exon 21) in 8 patients. Real-time PCR with the TaqMan MGB probes could detect all the mutations of EGFR found by sequencing. The sensitivity and specificity of the detection of EGFR mutations were both 100%. Real-time PCR with TagMan MGB probes could detect EGFR mutation in as rare as 50 EGFR mutant cells and in a proportion of 10% of mutant cells in a cell population. The mutations were significantly higher in the adenocarcinoma than in non-adenocarcinoma (16/38 vs. 5/42, chi2 = 9.702, P <0.01), in the female patients than in the male patients (14/29 vs. 7/51, chi2 = 11.4, P <0.01) and in non-smokers than in smokers (16/40 vs. 5/40, chi2 = 7.812, P < 0.01). The mutations were not related to patients'age, TNM staging, etc. CONCLUSION: Somatic mutations of EGFR gene develop in NSCLC and are more common in female, non-smoker and adenocarcinoma patients. Real-time PCR using TaqMan-MGB, which can be used to detect the EGFR gene mutations, is easy to operate and deserves widespread application.