Targeted therapies in the treatment of advanced/metastatic NSCLC

Novel EGFR inhibitors against resistant L858R/T790M/C797S mutant for intervention of non-small cell lung cancer

To overcome C797S mutation, the latest and most common resistance mechanism in the clinical treatment of third-generation EGFR inhibitor, a novel series of substituted 6-(2-aminopyrimidine)-indole derivatives were designed and synthesized. Through the structure-activity relationship (SAR) study, compound 11eg was identified as a novel and potent EGFR L858R/T790M/C797S inhibitor (IC50 = 0.053 μM) but had a weak effect on EGFRWT (IC50 = 1.05 μM). 11eg significantly inhibited the proliferation of the non-small cell lung cancer (NSCLC) cells harboring EGFRL858R/T790M/C797S with an IC50 of 0.052 μM. 11eg also showed potent inhibitory activity against other NSCLC cell lines harboring main EGFR mutants. Furthermore, 11eg exhibited much superior activity in arresting cell cycle and inducing apoptosis of NSCLC cells with mutant EGFRC797S. It blocked cellular EGFR signaling. Importantly, 11eg markedly suppressed the tumor growth in in vivo xenograft mouse model with good safety. Additionally, 11eg displayed good microsomal stability. These results demonstrated the potential of 11eg with novel scaffold as a promising lead compound targeting EGFRC797S to guide in-depth structural optimization.

Autophagy mediated targeting degradation, a promising strategy in drug development

Targeted protein degradation (TPD) technologies have become promising therapeutic approaches through degrading disease-causing proteins via the protein degradation system. Autophagy is a fundamental biological process with a high relationship to protein degradation, which belongs to one of two main protein degradation pathways, the autophagy-lysosomal system. Recently, various autophagy-based TPD techniques ATTECs, AUTACs, and AUTOTACs, etc, have also been gradually developed, and they have achieved efficient degradation potency for the targeted protein, expanding the potential of degradation for large-size proteins or protein aggregates. Herein, we introduce the machinery of autophagy and its relation to protein degradation, and multiple methods for using autophagy to specifically degrade target proteins.

Efficacy of Sorafenib-Based Therapies for Non-Small Cell Lung Cancer

Lung cancer remains the leading cause of cancer-related deaths, with a poor prognosis. Of the two types, non-small cell lung cancer (NSCLC) is the major and most prevalent type and associated with low response rates to the current treatment options. Sorafenib, a multitargeted tyrosine kinase inhibitor used for various malignancies, gained attention for its potential efficacy in NSCLC. This review paper focuses on the findings of recent in vitro, in vivo, and clinical studies regarding the efficacy of sorafenib. Overall, sorafenib has shown definitive therapeutic potential in NSCLC cell lines, xenografts, and human subjects. Novel approaches to sorafenib delivery may improve its efficacy and should be the focus of further studies.

Annual review of PROTAC degraders as anticancer agents in 2022

Following nearly two decades of development, significant advancements have been achieved in PROTAC technology. As of the end of 2022, more than 20 drugs have entered clinical trials, with ARV-471 targeting estrogen receptor (ER) showing remarkable progress by entering phase III clinical studies. In 2022, significant progress has been made on multiple targets. The first reversible covalent degrader designed to target the KRASG12C mutant protein, based on cyclopropionamide, has been reported. Additionally, the activity HDCA1 degrader surpassed submicromolar levels during the same year. A novel FEM1B covalent ligand called EN106 was also discovered, expanding the range of available ligands. Furthermore, the first PROTAC drug targeting SOS1 was reported. Additionally, the first-in-class degraders that specifically target BRD4 isoforms (BRD4 L and BRD4 S) have recently been reported, providing a valuable tool for further investigating the biological functions of these isoforms. Lastly, a breakthrough was also achieved with the first degrader targeting both CDK9 and Cyclin T1. In this review, we aimed to update the PROTAC degraders as potential anticancer agents covering articles published in 2022. The design strategies, degradation effects, and anticancer activities were highlighted, which might provide an updated sight to develop novel PROTAC degraders with great potential as anticancer agents as well as favorable drug-like properties.

Structure-based virtual screening and molecular dynamics simulations for detecting novel candidates for allosteric inhibition of EGFRT790M

Structure-based virtual screening (SBVS) was applied to predict lead compounds for the allosteric inhibition of epidermal growth factor receptor (EGFR) by screening the library of chemical compounds prepared from the e-molecules chemical database. The library of chemical compounds consisting of 133,083 ligands was composed by evaluating the chemical and physical properties of e-molecules chemicals. The prepared library was screened by CCDC Gold software in the allosteric binding site of EGFRT790M using the library and virtual screening default parameters to filter out, respectively. The GOLD fitness scores 75 and 80 were selected as threshold values for the library and virtual screening processes, respectively. After the docking study, molecular dynamics simulations (MDS) of the top 25 compounds were built for calculating binding free energies from their MDS trajectories. MM-GBSA binding free energies for the compounds were computed from 20 ns MDS, 50 ns MDS and 200 ns MDS trajectories to filter out the candidates. Following MM-GBSA/MM-PBSA binding free energy calculations, six compounds were detected as the most promising candidates for allosteric inhibition of EGFRT790M. The dynamic behaviors of final compounds inside EGFR T790M were searched using structure stability, binding modes and energy decomposition analysis. Besides, the estimated inhibitors were exposed to docking study and MM-GBSA/MM-PBSA binding free energy calculations inside wild-type EGFR, respectively, to be determined their selectivity towards mutant form. Five of the estimated inhibitors displayed estimated selectivity towards EGFRT790M. Besides the ADMET properties of the estimated inhibitors were predicted by PreAdmet tools.Communicated by Ramaswamy H. Sarma.

Synthesis and biological assessment of indole derivatives containing penta-heterocycles scaffold as novel anticancer agents towards A549 and K562 cells

Herein, a new series of 2-chloro-N-(5-(2-oxoindolin-3-yl)-4H-pyrazol-3-yl) acetamide derivatives containing 1,3,4-thiadiazole (10a-i) and 4H-1,2,4-triazol-4-amine (11a-r) moiety was designed, synthesised as novel anticancer agents. The antiproliferative activity values indicated that compound 10 b stood as the most potent derivative with IC₅₀ values of 12.0 nM and 10 nM against A549 and K562 cells, respectively. Mechanism investigation and docking studies of 10 b indicated that it possessed good apoptosis characteristic and dose-dependent growth arrest of A549 and K562 cells, blocked cell cycle into G2/M phase. Interestingly, 10 b suppressed the growth of A549 and K562 cells via modulation of EGFR and p53-MDM2 mediated pathway.

Insights into fourth generation selective inhibitors of (C797S) EGFR mutation combating non-small cell lung cancer resistance: a critical review

Lung cancer is the second most common cause of morbidity and mortality among cancer types worldwide, with non-small cell lung cancer (NSCLC) representing the majority of most cases. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) are among the most commonly used targeted therapy to treat NSCLC. Recent years have seen the evaluation of many synthetic EGFR TKIs, most of which showed therapeutic activity in pertinent models and were classified as first, second, and third-generation. The latest studies have concluded that their efficacy was also compromised by additional acquired mutations, including C797S. Because second- and third-generation EGFR TKIs are irreversible inhibitors, they are ineffective against C797S containing EGFR triple mutations (Del19/T790M/C797S and L858R/T790M/C797S). Therefore, there is an urgent unmet medical need to develop next-generation EGFR TKIs that selectively inhibit EGFR triple mutations via a non-irreversible mechanism. This review covers the fourth-generation EGFR-TKIs' most recent design with their essential binding interactions, the clinical difficulties, and the potential outcomes of treating patients with EGFR mutation C797S resistant to third-generation EGFR-TKIs was also discussed. Moreover, the utilization of various therapeutic strategies, including multi-targeting drugs and combination therapies, has also been reviewed.

Design, synthesis and biological evaluation of phosphoroxy quinazoline derivatives as potential EGFRT790M/C797S inhibitors

Owing to the urgency and importance of developing fourth-generation EGFR inhibitors that can effectively overcome C797S site mutation in NSCLC, Brigatinib was used in this work as a lead compound to modify its structure to obtain a series of phosphoroxy quinazoline derivatives. Biological study indicated that the inhibitory activity and selectivity of the target compounds on EGFR^{L858R/T790M/C797S}/EGFR^{Del19/T790M/C797S} enzymes and EGFR^{Del19/T790M/C797S} overexpressed Ba/F3 cells were significantly better than those of Brigatinib. Among the target compounds, 8a exhibited the best biological activity in vitro. More importantly, 8a presented acceptable pharmacokinetic behaviors and showed potent anti-tumor efficacy in the Ba/F3-EGFR^{Del19/T790M/C797S} subcutaneous xenograft mice model with the tumor growth inhibition value of 82.60% at a dose of 30 mg/kg. These results indicated that 8a, as a drug candidate of the novel fourth-generation EGFR small-molecule inhibitor, has high potentials to treat with NSCLC on EGFR with C797S mutation.

Single-Cell Analysis Reveals Transcriptomic Features of Drug-Tolerant Persisters and Stromal Adaptation in a Patient-Derived EGFR-Mutated Lung Adenocarcinoma Xenograft Model

INTRODUCTION

Targeted therapies require life-long treatment, as drug discontinuation invariably leads to tumor recurrence. Recurrence is mainly driven by minor subpopulations of drug-tolerant persister (DTP) cells that survive the cytotoxic drug effect. In lung cancer, DTP studies have mainly been conducted with cell line models.

METHODS

We conducted an in vivo DTP study using a lung adenocarcinoma patient-derived xenograft tumor driven by an EGFR mutation. Daily treatment of tumor-bearing mice for 5 to 6 weeks with the EGFR inhibitor erlotinib markedly shrunk tumors and generated DTPs, which were analyzed by whole exome, bulk population transcriptome, and single-cell RNA sequencing.

RESULTS

The DTP tumors maintained the genomic clonal architecture of untreated baseline (BL) tumors but had reduced proliferation. Single-cell RNA sequencing identified a rare (approximately 4%) subpopulation of BL cells (DTP-like) with transcriptomic similarity to DTP cells and intermediate activity of pathways that are up-regulated in DTPs. Furthermore, the predominant transforming growth factor-β activated cancer-associated fibroblast (CAF) population in BL tumors was replaced by a CAF population enriched for IL6 production. In vitro experiments indicate that these populations interconvert depending on the levels of transforming growth factor-β versus NF-κB signaling, which is modulated by tyrosine kinase inhibitor presence. The DTPs had signs of increased NF-κB and STAT3 signaling, which may promote their survival.

CONCLUSIONS

The DTPs may arise from a specific preexisting subpopulation of cancer cells with partial activation of specific drug resistance pathways. Tyrosine kinase inhibitor treatment induces DTPs revealing greater activation of these pathways while converting the major preexisting CAF population into a new state that may further promote DTP survival.

Progress of small molecules for targeted protein degradation: PROTACs and other technologies

Recent years have witnessed the rapid development of targeted protein degradation (TPD), especially proteolysis targeting chimeras. These degraders have manifested many advantages over small molecule inhibitors. To date, a huge number of degraders have been excavated against over 70 disease-related targets. In particular, degraders against estrogen receptor and androgen receptor have crowded into phase II clinical trial. TPD technologies largely expand the scope of druggable targets, and provide powerful tools for addressing intractable problems that can not be tackled by traditional small molecule inhibitors. In this review, we mainly focus on the structures and biological activities of small molecule degraders as well as the elucidation of mechanisms of emerging TPD technologies. We also propose the challenges that exist in the TPD field at present.

Overexpression of Progerin Results in Impaired Proliferation and Invasion of Non-Small Cell Lung Cancer Cells

Purpose

The accumulation of progerin (PG) in patients is responsible for the pathogenesis of Hutchinson-Gilford Progeria Syndrome (HGPS) because it triggers accelerated aging of cells. However, there are few studies on the effects of progerin on tumor cells. Lung cancer is one of the most common malignant cancers with high global morbidity and mortality rates; non-small cell lung cancer accounts for the majority of cases. The purpose of this study was to determine the effects of progerin on A549 cell proliferation, cell cycle, invasion, migration, sensitivity to DNA damaging agents, senescence and apoptosis with a goal of exploring new ideas for lung cancer treatment.

Methods

A549 cells overexpressing progerin (A549-PG) and a corresponding blank control (A549-GFP) were constructed by lentiviral infection. A nuclear staining assay was utilized to detect abnormal nuclear morphology. The proliferation, cell cycle, colony formation, invasion and migration abilities of A549-PG were compared with those of A549-GFP via EdU assays, flow cytometry, colony formation experiments, and Matrigel invasion and migration assays, respectively. SA‐β‐gal staining was used to measure senescence in cells.

Results

The expression of progerin was significantly higher in A549-PG than A549-GFP. About 20% of A549-PG possessed abnormal nuclei. Overexpression of progerin in A549 cells inhibited cell proliferation, migration and invasion, and associated proteins (CDK4, pRB, ANLN, MMP7 and MMP9) were downregulated. DNA damage repair was also impaired. Progerin did not cause cells to senesce, and there was no difference in apoptosis.

Conclusion

A549-PG generated some cellular changes, including the nuclear skeleton, the cell cycle, DNA damage repair, and migration and invasion abilities. Our data indicate that progerin could cause an imbalance in the steady state in A549 cells and increase their sensitivity to chemotherapeutic drugs.

In silico search of triple mutant T790M/C797S allosteric inhibitors to conquer acquired resistance problem in non-small cell lung cancer (NSCLC): a combined approach of structure-based virtual screening and molecular dynamics simulation

Third generation EGFR inhibitor osimertinib was approved as the first-line treatment for EGFR T790M mutation-positive Non-Small Cell Lung Cancer (NSCLC) patients in 2017. However, EGFR tertiary Cys797 to Ser797 (C797S) point mutation emanate rapidly after treatment of osimertinib, which is undruggable mutation to the all existing drugs. Recently, EAI045 fourth-generation allosteric EGFR inhibitor has been reported, which binds away from the ATP-binding site and not rely on Cys 797 binding. Here, we are reporting compound ZINC20531199 by virtual based screening studies as allosteric inhibitor to overcome the EGFR T790M/C797S Tyrosine Kinase (TK) mutation problem. Molecular Dynamics simulation for 10 ns further suggested that docked compound ZINC20531199 was stable into the allosteric pocket of the C797S EGFR tyrosine kinase. In silico pharmacokinetic predictions of the virtually screened compounds are within the defined range described for human use. Results indicate that the virtual screened compounds could be potential leads for the further development of new allosteric EGFR T790M/C797S inhibitors to overcome the problem of drug resistance.Communicated by Ramaswamy H. Sarma.

A Mechanistic Study of a Potent and Selective Epidermal Growth Factor Receptor Inhibitor against the L858R/T790M Resistance Mutation

Covalent targeting is a promising strategy for increasing the potency and selectivity of potential drug candidates. This therapeutic approach was recently reported for the epidermal growth factor receptor (EGFR), wherein a covalent binder, 20g [N-(3-{7-[2-methoxy-4-(4-methylpiperazin-1-yl)phenylamino]-3,4-dihydro-3-isopropyl-2,4-dioxopyrimido[4,5-d]pyrimidin-1(2H)-yl}phenyl)acrylamide], demonstrated significant selectivity and inhibitory activity toward the EGFR L858R/T790M double mutant (EGFR^DM) relative to the EGFR wild-type form (EGFR^WT). The enhanced therapeutic potency of 20g against EGFR^DM is 263 times greater than that against EGFR^WT, which necessitates a rational explanation for the underlying selective and inhibitory mechanisms. In this work, we investigate the differential binding modes of 20g with EGFR^WT and EGFR^DM using molecular dynamics simulations coupled with free energy calculations and further identify key residues involved in the selective targeting, binding, and inhibitory mechanisms mediated by 20g. We find that systematic orientational and conformational changes in the α-loop, p-loop, active loop, and αC-helix are responsible for the disparate binding mechanisms and inhibitory prowess of 20g with respect to EGFR^WT and EGFR^DM. The calculated binding free energies show good correlation with the experimental biological activity. The total binding free energy difference between EGFR^WT-20g and EGFR^DM-20g is -11.47 kcal/mol, implying that 20g binds more strongly to EGFR^DM. This enhanced binding affinity of 20g for EGFR^DM is a result of a large increase in the van der Waals and electrostatic interactions with three critical residues (Met790, Gln791, and Met793) that are chiefly responsible for the high-affinity interactions mediated by 20g with EGFR^DM relative to EGFR^WT.

In vitro study of the Polo-like kinase 1 inhibitor volasertib in non-small-cell lung cancer reveals a role for the tumor suppressor p53

Polo-like kinase 1 (Plk1), a master regulator of mitosis and the DNA damage response, is considered to be an intriguing target in the research field of mitotic intervention. The observation that Plk1 is overexpressed in multiple human malignancies, including non-small-cell lung cancer (NSCLC), gave rise to the development of several small-molecule inhibitors. Volasertib, presently the most extensively studied Plk1 inhibitor, has been validated to efficiently reduce tumor growth in preclinical settings. Unfortunately, only modest antitumor activity against solid tumors was reported in clinical trials. This discrepancy prompted research into the identification of predictive biomarkers. In this study, we investigated the therapeutic effect of volasertib monotherapy (i.e., cytotoxicity, cell cycle distribution, apoptotic cell death, cellular senescence, and migration) in a panel of NSCLC cell lines differing in p53 status under both normal and reduced oxygen tension (<0.1% O2 ). A strong growth inhibitory effect was observed in p53 wild-type cells (A549 and A549-NTC), with IC50 values significantly lower than those in p53 knockdown/mutant cells (A549-920 and NCI-H1975) (P < 0.001). While mitotic arrest was significantly greater in cells with nonfunctional p53 (P < 0.005), apoptotic cell death (P < 0.026) and cellular senescence (P < 0.021) were predominantly induced in p53 wild-type cells. Overall, the therapeutic effect of volasertib was reduced under hypoxia (P < 0.050). Remarkably, volasertib inhibited cell migration in all cell lines tested (P < 0.040), with the exception of for the NCI-H1975 p53 mutant cell line. In conclusion, our results show an important difference in the therapeutic effect of Plk1 inhibition in NSCLC cells with versus without functional p53. Overall, the p53 wild-type cell lines were more sensitive to volasertib treatment, suggesting that p53 might be a predictive biomarker for Plk1 inhibition in NSCLC. Moreover, our results pave the way for new combination strategies with Plk1 inhibitors to enhance antitumor activity.

Development and validation of generic heterogeneous fluoroimmunoassay for bioanalysis of bevacizumab and cetuximab monoclonal antibodies used for cancer immunotherapy

This study describes, for the first time, the development and validation of a highly selective and sensitive heterogeneous fluoroimmunoassay (FIA) for the bioanalysis of two monoclonal antibodies (mAbs) used for cancer immunotherapy: bevacizumab (BEV) and cetuximab (CET). The assay combines reliable non-competitive binding of BEV and CET to their specific cell receptor proteins (human vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR), respectively) with the highly specific fluorescence activity of the fluorescein isothiocyanate labeled anti-human IgG (FITC-IgG) used as label. The limits of detection were 14.14 and 1.27 × 10³ ng mL^-1 for BEV and CET, respectively. The accuracy and precision of the assay were demonstrated. The assay is simple, convenient, and requires very small volume (~ 5 µL) of plasma sample for analysis. The assay can offer high throughput analysis in clinical settings when modern microplates of multiplies of 96 (up to 6144-wells) are used and/or integrated as a part of automated robotic system. The proposed assay can be used for routine clinical bioanalysis of mAbs with potential application in pharmacokinetics, pharmacodynamics and therapeutic drug monitoring (TDM).

Automated flow fluorescent noncompetitive immunoassay for measurement of human plasma levels of monoclonal antibodies used for immunotherapy of cancers with KinExA™ 3200 biosensor

This study describes, for the first time, the development of an automated sensitive flow fluorescent noncompetitive immunoassay based on kinetic-exclusion analysis (KinExA) for the quantitative determination of human plasma levels of monoclonal antibodies (mAbs) used for cancer immunotherapy. The assay was adapted on KinExA™ 3200 biosensor and optimized and validated for bevacizumab (BEV) and cetuximab (CET), as representative examples of the mAbs, using their specific antigens. These antigens were the human vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) for BEV and CET, respectively. The limits of detection were 1.28 and 52.64 ng mL^-1 for BEV and CET, respectively. The accuracy of the assay was demonstrated with analytical recovery of analytes from spiked plasma at 96.2-104.3 and 96.8-105.3% for BEV and CET, respectively. The precision of the assay was satisfactory as shown by relative standard deviation (RSD) at 2.2-5.7 and 2.5-6.1% for assay of BEV and CET, respectively. The high sensitivity of the assay allowed the use of very small volumes (~ 1 µL) of plasma sample for analysis. Automated analysis by the proposed KinExA-based assay facilitates the processing of large numbers of mAbs-containing specimens in studies of pharmacokinetics (PK), pharmacodynamics (PD), and therapeutic drug monitoring (TDM) of therapeutic mAbs. The proposed assay can be used to overcome the problems encountered in the existing conventional immunoassays for mAbs.

Dual target gene therapy to EML4-ALK NSCLC by a gold nanoshell-based system

Although EML4-ALK transforming fusion gene is represented in only 8% of non-small cell lung cancer (NSCLC) cases, its expression is partly responsive for the failure of current NSCLC treatments. Preventing secondary mutation of the ALK protein through direct gene manipulation could overcome NSCLC drug resistance. Method: In this study, we developed a gold nanoshell (HAuNs) drug carrier for delivery and selective photo-thermal release of genes that target ALK and microRNA-301 in NSCLC. Additionally, the densely-coated nanoshell adsorbed high amounts of the positively-charged anticancer drug doxorubicin (DOX), generating an exciting multidimensional treatment strategy that includes gene-, thermal- and chemo- therapy. Results: The ALK mRNA and microRNA-301 genes as the double targets exhibited the combined effect. The drug carrier system significantly improved the drug accumulation in tumor tissues due to the enhanced vascular permeability by photothermal effect, dense spherical structure and RGD peptide modification. In vitro and in vivo results demonstrated the multiple therapeutic effects of the gold nanoshell-based system was better than the monotherapy. Conclusion: The above results indicated the gold nanoshell-based system would be a promising translational nano-formulation platform for effective treatment of EML4-ALK-positive NSCLC.

Bevacizumab and gefitinib enhanced whole-brain radiation therapy for brain metastases due to non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) patients who experience brain metastases are usually associated with poor prognostic outcomes. This retrospective study proposed to assess whether bevacizumab or gefitinib can be used to improve the effectiveness of whole brain radiotherapy (WBRT) in managing patients with brain metastases. A total of 218 NSCLC patients with multiple brain metastases were retrospectively included in this study and were randomly allocated to bevacizumab-gefitinib-WBRT group (n=76), gefitinib-WBRT group (n=77) and WBRT group (n=75). Then, tumor responses were evaluated every 2 months based on Response Evaluation Criteria in Solid Tumors version 1.0. Karnofsky performance status and neurologic examination were documented every 6 months after the treatment. Compared to the standard WBRT, bevacizumab and gefitinib could significantly enhance response rate (RR) and disease control rate (DCR) of WBRT (P<0.001). At the same time, RR and DCR of patients who received bevacizumab-gefitinib-WBRT were higher than those who received gefitinib-WBRT. The overall survival (OS) rates and progression-free survival (PFS) rates also differed significantly among the bevacizumab-gefitinib-WBRT (48.6 and 29.8%), gefitinib-WBRT (36.7 and 29.6%) and WBRT (9.8 and 14.6%) groups (P<0.05). Although bevacizumab-gefitinib-WBRT was slightly more toxic than gefitinib-WBRT, the toxicity was tolerable. As suggested by prolonged PFS and OS status, bevacizumab substantially improved the overall efficacy of WBRT in the management of patients with NSCLC.

Metuzumab enhanced chemosensitivity and apoptosis in non-small cell lung carcinoma

Targeted therapeutics is used as an alternative treatment of non-small cell lung cancer (NSCLC); however, treatment effect is far from being satisfactory, and therefore identification of new targets is needed. We have previously shown that metuzumab inhibit tumor growth in vivo. The present study was performed to investigate the anti-tumor efficacy of metuzumab combined with gemcitabine and cisplatin (GP), paclitaxel and cisplatin (TP) or navelbine and cisplatin (NP) regimens in multiple NSCLC cell lines. Our results demonstrate that, in comparison to single agent metuzumab or GP treated cells, metuzumab combined with GP display inhibitory effects on tumor growth. Furthermore, we found that metuzumab elevated the sensitivity of cell lines to gemcitabine, which was identified by MTT assay. Flow cytometric analysis showed that metuzumab combined with gemcitabine (GEM) treatment led to an obvious G1 arrest and an elevated apoptosis in A549, NCI-H460 and NCI-H520 cells. Western blot analysis also demonstrated a significantly reduced level of cyclin D1, Bcl-2, and an obviously increase level of Bax and full-length caspase-3 in A549, NCI-H460 and NCI-H520 cells treated with metuzumab/gemcitabine combination in comparison with single agent treated cells. In addition, metuzumab/gemcitabine treated A549, NCI-H460 and NCI-H520 cells also demonstrated a significantly increase in deoxycytidine kinase (dCK) protein level compared with single agent metuzumab or gemcitabine treated cells. Xenograft models also demonstrated that this metuzumab/gemcitabine combination led to upregulation of dCK. Taken together, the mechanisms of metuzumab combined with GP repress tumor growth were that the combined treatment significantly inhibited the tumor cell proliferation, apoptosis and cell cycle in vitro and in vivo and at least partially by induction of dCK expression. Our results suggested that metuzumab could significantly enhance chemosensitivity of human NSCLC cells to gemcitabine. Metuzumab/gemcitabine combination treatment may be a potentially useful therapeutic regimen for NSCLC patients.

Diagnostic Utility of Bronchial Brush-Tip Washings for the Immunohistochemical Assessment of Peripheral Lung Lesions

OBJECTIVES

Immunohistochemistry (IHC) is an important component of lung cancer diagnosis and management, although performance can be limited due to tissue availability. We describe a novel technique for processing brush-tip washings (BTW) and evaluate the feasibility of IHC testing on these samples.

STUDY DESIGN

All patients who had cell blocks (CB) created from BTW following bronchoscopic investigation of peripheral lung lesions were included. CB were assessed for adequate material before undergoing IHC staining.

RESULTS

75 patients were included in the study, with bronchoscopic diagnosis of malignancy achieved in 77%. Sixty-seven samples (89%) had sufficient cells for diagnosis on CB and 56 of these (84%) proved amenable to IHC. CB created from BTW were the sole specimens available for IHC subtyping in 7 patients (9%).

CONCLUSIONS

CB are easily created from BTW and are a simple method for increasing the diagnostic utility of bronchoscopic specimens without increasing the risk or duration of bronchoscopy. IHC can be easily performed in a high proportion of cases, increasing the likelihood of accurate sub-typing of tumours following diagnostic bronchoscopy.

Challenges and Perspectives on the Development of Small-Molecule EGFR Inhibitors against T790M-Mediated Resistance in Non-Small-Cell Lung Cancer

Because of the development of drug-resistance mutations, particularly the "gatekeeper" threonine(790)-to-methionine(790) (T790M) mutation in the ATP-binding pocket of the epidermal growth factor receptor (EGFR), the current generation of EGFR tyrosine kinase inhibitors lost their clinical efficacy. Recently, a large number of small-molecule inhibitors with striking inhibitory potency against EGFR mutants with the T790M change have been identified. In particular, the inhibitors rociletinib and osimertinib, which can selectively target both sensitizing mutations and the T790M resistance while sparing the wild-type (WT) form of the receptor, have been designated as breakthrough therapies in the treatment of mutant non-small-cell lung cancer (NSCLC) by the U.S. FDA in 2014. We hope that this review on the small-molecule EGFR T790M inhibitors, along with their discovery strategies, will assist in the design of future T790M-containing EGFR inhibitors with high levels of selectivity over WT EGFR, broad kinase selectivity, and desirable physicochemical properties.

Evaluation of 29 indicators for the prognosis of advanced non-small cell lung cancer with cytokine-induced killer cell therapy combined with chemotherapy

The aim of the present study was to evaluate 29 whole blood or serum indicators to identify factors able to predict clinical outcome following cytokine-induced killer (CIK) cell therapy combined with chemotherapy in patients with advanced non-small cell lung cancer (NSCLC), and to evaluate the 5-year prognosis of the patients. From March 2008 to October 2013, 42 patients with advanced NSCLC (stages III and IV) were enrolled in the study. These patients were from a single hospital, and had been treated with CIK therapy combined with chemotherapy. Evaluation of the correlation between prognosis and age, gender, tumor stage, surgery resection status, number of CIK therapy cycles, tumor subtype, and the differential whole blood or serum indicators were analyzed by Kaplan-Meier methods and the log-rank test. The prognostic factors were analyzed by Cox proportional models. The median progression-free survival (mPFS) time of patients with high expression levels of albumin [20.0 months; 95% confidence interval (CI): 17.4–22.6 months] was significantly longer than the mPFS for patients with low expression levels of albumin (36.0 months; 95% CI: 24.7–47.3 months) (P=0.034). Other factors demonstrated no significant difference. Following analysis using the Cox proportional hazards regression model, the number of CIK therapy cycles (P=0.041) and the expression level of albumin (P=0.038) were revealed to be independent prognostic factors following the use of CIK cell therapy combined with chemotherapy for patients with advanced NSCLC. The risk of adverse outcomes in patients receiving ≥4 CIK therapy cycles and in patients with increased expression levels of albumin were 0.38 (95% CI: 0.14–1.13) and 0.32 (95% CI: 0.10–1.24)-fold those of patients receiving <4 CIK therapy cycles and with decreased expression levels of albumin, respectively. The serum albumin concentration may therefore be a predictor of the 5-year survival rate of patients with advanced NSCLC treated with CIK cell therapy combined with chemotherapy; patients with high expression levels of albumin may have a better prognosis in comparison with patients with low expression levels of albumin.

Expression of the CXCR4 ligand SDF-1/CXCL12 is prognostically important for adenocarcinoma and large cell carcinoma of the lung

The SDF-1/CXCR4 axis is associated with tumor progression and has been reported as a prognostic parameter, although with conflicting data for non-small cell lung cancer (NSCLC). This study examines a large cohort of clinically and pathologically well-characterized NSCLC patients and includes the activated form of CXCR4 (pCXCR4), which has not been studied in this context so far. SDF-1, CXCR4, and pCXCR4 were assessed immunohistochemically in 371 surgically resected NSCLC using a standardized tissue microarray platform. Extensive clinical and pathological data and a postoperative follow-up period of 17 years enabled detailed correlations. CXCR4 and pCXCR4 were frequently expressed on squamous cell carcinoma. Membranous expression of SDF-1 was a marker of poor prognosis and proved to be an independent prognostic parameter for the entire cohort and for patients with adenocarcinoma (ACA) and large cell carcinoma (LCC). Targeted cancer therapies blocking SDF-1/CXCR4 interaction already exist, and our data suggest that expression of SDF-1, especially on poorer prognosis subgroups of LCC and ACA, indicates patients that might benefit more than others. This should be taken into account when assessing the effectiveness of such targeted approaches for NSCLC patients and could lead to important implications.

Evaluation of Safety and Efficacy of Salvage Therapy With Sunitinib, Docetaxel (Tyxan) and Cisplatinum Followed by Maintenance Vinorelbine for Unresectable/Metastatic Nonsmall Cell Lung Cancer: Stage 1 of a Simon 2 Stage Clinical Trial. [Corrected]

Current chemotherapeutic regimens for nonsmall cell lung cancer (NSCLC) have reached a plateau over the last few years. Targeted therapy makes use of tyrosine kinase inhibitors (TKIs) to suppress a number of signaling pathways including epidermal growth factor receptor and vascular endothelial growth factor which are active in NSCLC biology. In this study, we used sunitinib, a multi-target receptor TKI, combined with chemotherapy for unresectable/metastatic NSCLC.This open label Simon's 2 stage clinical trial enrolled a total of 6 NSCLC patients who received docetaxel (40 mg) and cisplatin (50 mg) on day 1 of each cycle (14 day interval between cycles) and sunitinib (25 mg qd for 10 days between cycles) for a total of 12 cycles (24 weeks), after which patients received maintenance therapy with vinorelbine (30 mg TIW) until disease progression. The sample size was based on a Simon's Optimal Two-Stage Designs for Phase II clinical trials. The expected response rate was set as 35% for P0 and as 60% for P1. The study was designed for a minimum of 6 patients for first stage and 15 patients until second stage with a significance level alpha = 0.10 and power = 70%. Diagnosis of a poor response in the second of 6 patients in Stage I or seventh of the 15 patients in Stage II would lead to early termination of the trial.The overall response rate was 66.7%. Four patients had an overall survival >60 months. The time to PFS ranged from 3 to 42 months. The combination therapy was well-tolerated.Sunitinib combined with chemotherapy shows promise and warrants further investigation.

Impact of TG4010 Vaccine on Health-Related Quality of Life in Advanced Non-Small-Cell Lung Cancer: Results of a Phase IIB Clinical Trial

BACKGROUND

This study describes the effect of TG4010 vaccine on Health related Quality of Life (HRQOL) in patients with stage IIIb and IV non-small-cell lung cancer (NSCLC).

METHODS

148 patients with advanced NSCLC expressing MUC1 were randomly assigned to receive TG4010 plus chemotherapy or chemotherapy alone. HRQOL was assessed with the Functional Assessment of Cancer Therapy-Lung (FACT-L) at baseline and every 6 weeks until disease progression. Time until definitive deterioration (TUDD) of the four well-being dimensions of the FACT-L physical (PWB), functional (FWB), emotional (EWB) and social well-being (SWB) and the Lung Cancer Subscale (LCS) domains were analyzed for a 5-point minimal clinically important difference.

RESULTS

No difference of TUDD of HRQOL has been found between treatment arms. No prognostic factors have been found to have a significant impact on the TUDD of PWB, SWB and LCS domains. The gender, the performance status and the smoking habits seemed to be associated with a shorter TUDD of EWB domain. The smokers and the former smokers seemed to present a shorter TUDD of FWB domain.

CONCLUSION

This study suggests that adding therapeutic vaccination with TG4010 to standard chemotherapy in patients with advanced NSCLC is associated with a similar evolution in HRQOL compared to chemotherapy alone.

Simulation and comparison of progression-free survival among patients with non-squamous non-small-cell lung cancer receiving sequential therapy

OBJECTIVES

In recent years, the treatment landscape in advanced non-squamous non-small-cell lung cancer (nsNSCLC) has changed. New therapies (e.g., bevacizumab indicated in first line) have become available and other therapies (e.g., pemetrexed in first line and second line) moved into earlier lines in the treatment paradigm. While there has been an expansion of the available treatment options, it is still a key research question which therapy sequence results in the best survival outcomes for patients with nsNSCLC.

METHODS

A therapy-sequencing disease model that approximates treatment outcomes in up to five lines of treatment was developed for patients with nsNSCLC. The primary source of data for progression-free survival (PFS) and time to death was published pivotal trial data. All patients were treatment-naïve and in the PFS state, received first-line treatment with either bevacizumab-based therapy or doublet chemotherapy (including the option of pemetrexed + cisplatin). Patients would then progress to a subsequent line of therapy, remain in PFS or die. In case of progression, it was assumed that each survivor would receive a subsequent line of therapy, based on EMA licensed therapies. Weibull distribution curves were fitted to the data.

RESULTS

All bevacizumab-based first-line therapy sequences analyzed achieved total PFS of around 15 months. Bevacizumab + carboplatin + paclitaxel (first line) → pemetrexed (second line) → erlotinib (third line) → docetaxel (fourth line) resulted in total mean PFS time of 15.7 months, for instance. Sequences with pemetrexed in combination with cisplatin in first line achieved total PFS times between 12.6 and 12.8 months with a slightly higher total PFS time achieved when assuming pemetrexed continuation therapy in maintenance after pemetrexed + cisplatin in first-line induction. Overall survival results followed the same trend as PFS.

CONCLUSION

The model suggests that treatment-sequencing strategies starting with a bevacizumab-based combination in first line yield better survival outcomes than those starting with pemetrexed-based combinations, a result that is attributable to the possibility of one further line of treatment with first-line bevacizumab-based treatment sequences.

Prognostic value of HMGB3 expression in patients with non-small cell lung cancer

HMGB3 overexpression has been reported in a variety of human cancers. However, the role of HMGB3 in human non-small cell lung cancer (NSCLC) remains unclear. In this study, the HMGB3 expression was examined at mRNA and protein levels by quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR), Western blotting, and immunohistochemistry in NSCLC tissues and adjacent non-cancerous tissues. Statistical analyses were applied to test the associations between HMGB3 expression, clinicopathologic factors, and prognosis. Western blotting and qRT-PCR showed that the expression levels of HMGB3 mRNA and protein were both significantly higher in NSCLC tissues than those in non-cancerous tissues. Immunohistochemistry analysis showed that HMGB3 expression was significantly correlated with tumor grade, tumor size, clinical stage, and lymph node metastases. The results of Kaplan-Meier analysis indicated that a high expression level of HMGB3 resulted in a significantly poor prognosis of NSCLC patients. Importantly, multivariate analysis showed that high HMGB3 expression was an independent prognostic factor for NSCLC patients. In sum, our data suggest that HMGB3 plays an important role in NSCLC progression, and that overexpression of HMGB3 in tumor tissues could be used as a potential prognostic marker for patients with NSCLC.

Targeting tumor neovasculature in non-small-cell lung cancer

Recent insight into the molecular biology of cancer and mechanisms of tumorigenesis, has allowed for the identification of several potential molecular targets and the development of novel "targeted therapies". One of the most active research fields in NSCLC is the discovery of therapies that target angiogenesis. The vascular endothelial growth factor (VEGF) pathway represents a crucial component of the tumor angiogenesis process. Two different strategies have been developed in clinical practice in order to restrict tumor vasculature development; either the use of monoclonal antibodies against VEGF or small molecule tyrosine kinase inhibitors to target the tyrosine kinase domain of VEGF receptor. Among these agents that have been tested bevacizumab, a monoclonal antibody against VEGF, has been approved for the treatment of metastatic NSCLC in combination with chemotherapy, while several other agents are under phase III investigation. Moreover, several issues such as predictive biomarkers of response to antiangiogenic therapy and mechanisms of resistance to these agents remain to be elucidated. The purpose of this paper is to present the current status of antiangiogenic therapies in the treatment of NSCLC and to discuss these issues.

Intratumoral injection of taxol in vivo suppresses A549 tumor showing cytoplasmic vacuolization

Based on our recent in vitro studies, this report was designed to explore the mechanism by which high concentration of taxol (70 µM) induced paraptosis-like cell death in human lung carcinoma (A549) cells, and to evaluate the therapeutic efficacy of taxol using A549 tumor-bearing mice in vivo. Exposure of cells to taxol induced time-dependent cytotoxicity and cytoplasmic vacuolization without the involvement of Bax, Bak, Mcl-1, Bcl-XL, and caspase-3. Although taxol treatment induced activating transcription factor 6 (ATF6) cleavage indicative of endoplasmic reticulum (ER) stress, silencing ATF6 by shATF6 did not prevent taxol-induced both cytotoxcity and cytoplasmic vacuolization, suggesting that taxol-induced cytoplasmic vacuolization and cell death were not due to ER stress. Moreover, taxol-treated cells did not show DNA fragmentation and loss of mitochondrial membrane potential, the typical characteristics of apoptosis. In addition, taxol-induced cytoplasmic vacuolization did not show the cellular lysis, the characteristics of oncosis, and positive of β-galactosidase, the characteristic of senescence, indicating that taxol induced paraptosis-like cell death is neither oncosis nor senescence. Moreover, our in vivo data showed that intratumoral injection of taxol (50 mg/kg) in A549 tumor xenograft mice on day 1 and day 19 potently suppressed tumor growth showing significant ER vacuolization without toxicity. In conclusion, high concentration of taxol exhibits a significant anticancer activity by inducing paraptosis-like cell death in vitro and in vivo, without significant toxicity, suggesting a promising therapeutic strategy for apoptosis-resistance cancer by inducing ER vacuolization.

IGF-1 activates the P13K/AKT signaling pathway via upregulation of secretory clusterin

Secretory clusterin (sCLU) is a type of stress-induced, pro-survival glycoprotein elevated in early-stage cancer. It enhances cancer cell survival and is associated with several types of cancer progression. In this study, we measured the PI3K/AKT signaling activity by determining the phosphorylation level of the AKT protein, namely pAKT. A549 human non-small cell lung carcinoma (NSCLC) cells were treated with insulin-like growth factor-1 (IGF-1) for various periods of time. The results showed that IGF-1 activated the PI3K/AKT signaling pathway in the A549 cells in a time-dependent manner. Western blot analysis was performed to determine the expression of sCLU protein in A549 cells treated with IGF-1. IGF-1 elevated the expression of sCLU. To determine whether sCLU is required for the IGF-1 activation of the PI3K/AKT signaling pathway, the A549 cells were treated with IGF-1 and sCLU antisense oligonuleotide (sCLU ASO). sCLU ASO blocked the IGF-1 activation of the PI3K/AKT signaling pathway. These results demonstrate that IGF-1 activates the P13K/AKT signaling pathway via the upregulation of sCLU. The present study implies that this pathway may uncover a new mechanism for cancer progression and reveal new targets for drug development in the treatment of NSCLC.

Phosphodiesterase-4 promotes proliferation and angiogenesis of lung cancer by crosstalk with HIF

Lung cancer is the leading cause of cancer death worldwide. Recent data suggest that cyclic nucleotide phosphodiesterases (PDEs) are relevant in various cancer pathologies. Pathophysiological role of phosphodiesterase 4 (PDE4) with possible therapeutic prospects in lung cancer was investigated. We exposed 10 different lung cancer cell lines (adenocarcinoma, squamous and large cell carcinoma) to hypoxia and assessed expression and activity of PDE4 by real-time PCR, immunocytochemistry, western blotting and PDE activity assays. Expression and activity of distinct PDE4 isoforms (PDE4A and PDE4D) increased in response to hypoxia in eight of the studied cell lines. Furthermore, we analyzed various in silico predicted hypoxia-responsive elements (p-HREs) found in in PDE4A and PDE4D genes. Performing mutation analysis of the p-HRE in luciferase reporter constructs, we identified four functional HRE sites in the PDE4A gene and two functional HRE sites in the PDE4D gene that mediated hypoxic induction of the reporter. Silencing of hypoxia-inducible factor subunits (HIF1α and HIF2α) by small interfering RNA reduced hypoxic induction of PDE4A and PDE4D. Vice versa, using a PDE4 inhibitor (PDE4i) as a cyclic adenosine monophosphate (cAMP) -elevating agent, cAMP analogs or protein kinase A (PKA)-modulating drugs and an exchange protein directly activated by cAMP (EPAC) activator, we demonstrated that PDE4-cAMP-PKA/EPAC axis enhanced HIF signaling as measured by HRE reporter gene assay, HIF and HIF target genes expression ((lactate dehydrogenase A), LDHA, (pyruvate dehydrogenase kinase 1) PDK1 and (vascular endothelial growth factor A) VEGFA). Notably, inhibition of PDE4 by PDE4i or silencing of PDE4A and PDE4D reduced human lung tumor cell proliferation and colony formation. On the other hand, overexpression of PDE4A or PDE4D increased human lung cancer proliferation. Moreover, PDE4i treatment reduced hypoxia-induced VEGF secretion in human cells. In vivo, PDE4i inhibited tumor xenograft growth in nude mice by attenuating proliferation and angiogenesis. Our findings suggest that PDE4 is expressed in lung cancer, crosstalks with HIF signaling and promotes lung cancer progression. Thus, PDE4 may represent a therapeutic target for lung cancer therapy.

Bevacizumab-induced alterations in vascular permeability and drug delivery: a novel approach to augment regional chemotherapy for in-transit melanoma

PURPOSE

To investigate whether the systemically administered anti-VEGF monoclonal antibody bevacizumab could improve regional chemotherapy treatment of advanced extremity melanoma by enhancing delivery and tumor uptake of regionally infused melphalan (LPAM).

EXPERIMENTAL DESIGN

After treatment with systemic bevacizumab or saline, changes in vascular permeability were determined by spectrophotometric analysis of tumors infused with Evan's blue dye. Changes in vascular structure and tumor hemoglobin-oxygen saturation HbO(2) were determined by intravital microscopy and diffuse reflectance spectroscopy, respectively. Rats bearing the low-VEGF secreting DM738 and the high-VEGF secreting DM443 melanoma xenografts underwent isolated limb infusion (ILI) with melphalan (LPAM) or saline via the femoral vessels. The effect of bevacizumab on terminal drug delivery was determined by immunohistochemical analysis of LPAM-DNA adducts in tumor tissues.

RESULTS

Single-dose bevacizumab given three days before ILI with LPAM significantly decreased vascular permeability (50.3% in DM443, P < 0.01 and 35% in DM738, P < 0.01) and interstitial fluid pressure (57% in DM443, P < 0.01 and 50% in DM738, P = 0.01). HbO(2) decreased from baseline in mice following treatment with bevacizumab. Systemic bevacizumab significantly enhanced tumor response to ILI with LPAM in two melanoma xenografts, DM443 and DM738, increasing quadrupling time 37% and 113%, respectively (P = 0.03). Immunohistochemical analyses of tumor specimens showed that pretreatment with systemic bevacizumab markedly increased LPAM-DNA adduct formation.

CONCLUSIONS

Systemic treatment with bevacizumab before regional chemotherapy increases delivery of LPAM to tumor cells and represents a novel way to augment response to regional therapy for advanced extremity melanoma.

Epidermal growth factor receptor and K-Ras mutations and resistance of lung cancer to insulin-like growth factor 1 receptor tyrosine kinase inhibitors

BACKGROUND

Most patients with nonsmall cell lung cancer (NSCLC) have responded poorly to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). The authors investigated the involvement of insulinlike growth factor 1 receptor (IGF-1R) signaling in primary resistance to EGFR TKIs and the molecular determinants of resistance to IGF-1R TKIs.

METHODS

Phosphorylated IGF-1R/insulin receptor (pIGF-1R/IR) was immunohistochemically evaluated in an NSCLC tissue microarray. The authors analyzed the antitumor effects of an IGF-1R TKI (PQIP or OSI-906), either alone or in combination with a small-molecular inhibitor (PD98059 or U0126) or with siRNA targeting K-Ras or mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK), in vitro and in vivo in NSCLC cells with variable histologic features and EGFR or K-Ras mutations.

RESULTS

pIGF-1R/IR expression in NSCLC specimens was associated with a history of tobacco smoking, squamous cell carcinoma histology, mutant K-Ras, and wild-type (WT) EGFR, all of which have been strongly associated with poor response to EGFR TKIs. IGF-1R TKIs exhibited significant antitumor activity in NSCLC cells with WT EGFR and WT K-Ras but not in those with mutations in these genes. Introduction of mutant K-Ras attenuated the effects of IGF-1R TKIs on NSCLC cells expressing WT K-Ras. Conversely, inactivation of MEK restored sensitivity to IGF-TKIs in cells carrying mutant K-Ras.

CONCLUSIONS

The mutation status of both EGFR and K-Ras could be a predictive marker of response to IGF-1R TKIs. Also, MEK antagonism can abrogate primary resistance of NSCLC cells to IGF-1R TKIs.

[Vandetanib treatment in refractory advanced lung adenocarcinoma patients: five cases and review of literature]

背景与目的

凡德他尼是一种多靶点口服的小分子抑制剂，可同时作用于血管内皮生长因子受体、表皮生长因子受体、RET酪氨酸激酶转染中的重排，本研究旨在探讨凡德他尼治疗晚期复治肺腺癌患者的疗效和副反应。

方法

患者经过化疗和特罗凯治疗失败后，给予凡德他尼300 mg每日1次口服。

结果

5例患者中，2例（40%）最佳疗效达疾病稳定（stable disease, SD），3例（60%）疗效均为疾病进展（progressive disease, PD）。随访40个月，1例患者目前仍在随访中。中位无疾病进展时间（progression free survival, PFS）为2个月，平均总生存期（overall survival, OS）为22.6个月。出现副反应包括皮疹（n=2）、皮肤改变（n=2）、甲沟炎（n=2）、无症状的心电图QTc延长（n=2）、ST-T改变（n=1）、腹泻（n=1）、转氨酶增高（n=1）。

结论

凡德他尼治疗晚期复治肺腺癌患者中位PFS为2个月，平均OS为22.6个月，具有较好的安全性，结果同相关文献报道类似。

Targeted (and chemotherapeutic) agents as maintenance treatment in patients with metastatic non-small-cell lung cancer: current status and future challenges

Maintenance treatment has been intensively investigated in the field of advanced/metastatic non-small lung cancer in order to improve outcomes in this devastating disease. Two different approaches have been evaluated; the so-called continuation maintenance when the maintenance agent was part of initial therapy and is continued in the absence of disease progression ("maintained") or switch maintenance when a third agent is initiated after a defined number of cycles chemotherapy in the absence of disease progression. Several phase III trials with both chemotherapeutic and targeted agents have demonstrated either PFS prolongation (continuation maintenance) or both PFS and OS benefit (switch maintenance). Currently, erlotinib and pemetrexed are registered as maintenance treatment in patients with NSCLC not progressing after four cycles of standard platinum-based doublet chemotherapy. However, the development of maintenance treatment has raised a series of questions such as the role of treatment-free intervals, the timing of second-line treatment, selection of patients for maintenance treatment and selection of the most proper agent, and trial design issues such as optimal end-points. The purpose of this paper is to present and discuss the current trials investigating the main treatment paradigms and argue on the above mentioned questions.

Overexpression of polo-like kinase 1 and its clinical significance in human non-small cell lung cancer

Polo-like kinase 1 is a serine/threonine kinase which plays an essential role in mitosis and malignant transformation. The aim of this study was to investigate the prognostic significance of polo-like kinase 1 expression and determine its possibility as a therapeutic target in non-small cell lung cancer. Semi-quantitative RT-PCR assay was performed to detect polo-like kinase 1 mRNA expression in non-small cell lung cancer cells or tissues. Immunohistochemistry was performed to detect polo-like kinase 1 protein expression in 100 non-small cell lung cancer tissue samples, and the associations of polo-like kinase 1 expression with clinicopathological factors or prognosis of non-small cell lung cancer patients were evaluated. RNA interference was employed to inhibit endogenous polo-like kinase 1 expression and analyzed the effects of polo-like kinase 1 inhibition on the malignant phenotypes of non-small cell lung cancer cells including growth, apoptosis, radio- or chemoresistance. Also, the possible molecular mechanisms were also investigated. The levels of polo-like kinase 1 mRNA expression in non-small cell lung cancer cell lines or tissues were significantly higher than those in normal human bronchial epithelial cell line or corresponding non-tumor tissues. High polo-like kinase 1 expression was significantly correlated with advanced clinical stage, higher tumor classification and lymph node metastasis of non-small cell lung cancer patients (P=0.001, 0.004 and 0.001, respectively). Meanwhile, high polo-like kinase 1 protein expression was also an independent prognostic molecular marker for non-small cell lung cancer patients (hazard ratio: 2.113; 95% confidence interval: 1.326-3.557; P=0.017). Polo-like kinase 1 inhibition could significantly inhibit in vitro and in vivo proliferation, induce cell arrest of G(2)/M phase and apoptosis enhancement in non-small cell lung cancer cells, which might be activation of the p53 pathway and the Cdc25C/cdc2/cyclin B1 feedback loop. Further, inhibition of polo-like kinase 1 could enhance the sensitivity of non-small cell lung cancer cells to taxanes or irradiation. Thus, polo-like kinase 1 might be a prognostic marker and a chemo- or radiotherapeutic target for non-small cell lung cancer.

Prognostic role of ERCC1 in advanced non-small-cell lung cancer: a systematic review and meta-analysis

Small observational studies have demonstrated an association between high ERCC1 expression level and poor prognosis in advanced NSCLC treated with platinum-based chemotherapy. This meta-analysis presents pooled estimates of association from 11 studies. High ERCC1 patients had lower response rates and higher risk of death relative to low ERCC1 patients. These results support the prognostic significance of ERCC1 expression level in advanced NSCLC.

BACKGROUND

Observational studies have demonstrated an association between excision repair cross-complementation group 1 (ERCC1) expression level and health outcomes in patients with advanced non-small-cell lung cancer (NSCLC) treated with platinum-based regimens. This analysis presents pooled estimates of association from these studies to better elucidate the prognostic role of ERCC1 in advanced NSCLC.

METHODS

A systematic literature search was conducted using the MEDLINE, EMBASE, and American Society of Clinical Oncology (ASCO) annual meeting databases from June 1995 to December 2010. Included studies were evaluated for clinical, methodological, and statistical heterogeneity. Pooled analyses were conducted using fixed and random effects models.

RESULTS

In high ERCC1 expression versus low ERCC1 expression patients, pooled analysis results demonstrated a significantly lower response (risk ratio [RR], 0.80, 0.66-0.98) and significantly higher risk of death (hazard ratio [HR], 2.04, (1.48-2.80)), respectively. Subgroup analyses demonstrated significant heterogeneity in outcomes by ERCC1 measurement method (I(2): 90.7%, P = 0.001) and patient population ethnicity (I(2): 66%, P = 0.003).

CONCLUSION

This study's findings support the hypothesis that ERCC1 expression is associated with response rate and overall survival (OS) in patients with advanced NSCLC treated with platinum-based chemotherapy. Heterogeneity in subgroup analyses demonstrates the need for standardized methods to classify ERCC1 expression level, studies evaluating the association between ERCC1 expression and OS in non-Asian populations, and studies evaluating interaction between ERCC1 and other known prognostic factors in advanced NSCLC.

Vortex keratopathy in a patient receiving vandetanib for non-small cell lung cancer

We report a case of vortex keratopathy in a patient treated with vandetanib for non-small cell lung cancer (NSCLC). A 44-year-old female who underwent two cycles of chemotherapy for NSCLC complained of visual blurring in both eyes after the initiation of vandetanib, an anti-epidermal growth factor receptor (EGFR) and anti-vascular endothelial growth factor receptor 2 protein tyrosine kinase inhibitor. On ophthalmic examination, visual acuities were 20 / 20 OU and, with the exception of diffuse vortex keratopathy in both eyes, other findings were unremarkable. Vandetanib is believed to have caused vortex keratopathy in this patient. Anti-EGFR properties affecting normal corneal epithelial cell migration and wound healing or drug associated metabolite deposition, which is the case in numerous drug-associated vortex keratopathies, may be possible underlying mechanisms in the formation of this corneal complication.