Highlights from the Tenth World Conference on Lung Cancer

TXA9, a cardiac glycoside from Streptocaulon juventas, exerts a potent anti-tumor activity against human non-small cell lung cancer cells in vitro and in vivo

Non-small cell lung cancer is the most common type of lung cancer and the most common cause of cancer-related death in humans. TXA9, which is a natural product separated from an anti-tumor-active fraction of the roots of Streptocaulon juventas, may possess potent anti-proliferative activity according to the present study. In this study, the anti-tumor effects and toxicity of TXA9 were tested against human non-small cell lung cancer cell lines (A549, NCI-H1299, Ltep-α2, PC-9, and Lu99) and a normal human lung embryonic fibroblast cell (HE-lung) in vitro, and then toward A549 cells in vivo in a murine xenograft model. The results show that TXA9 exhibits potent cytotoxic activities against non-small lung cancer cells and has no toxic effect on the normal human lung embryonic fibroblast cells. The mechanistic studies demonstrate that TXA9 can induce the apoptosis of A549 cells through the extrinsic pathway. The in vivo study results reveal that the intravenous administration of TXA9 at high-dose (15 mg kg(-1)) induces significant tumor growth inhibition of non-small cell lung cancer xenografts with tumor inhibition rate up to 64.2%, compared with mice in the control group. The inhibitory effect was similar to that of taxol (62.5%). In particular, no significantly adverse effects were exerted by TXA9, which suggests that it is well tolerated. This promising natural product may be useful as a potential novel anti-tumor candidate.

Cardiac glycosides induce autophagy in human non-small cell lung cancer cells through regulation of dual signaling pathways

Na(+)/K(+)-ATPase targeted cancer therapy has attracted increasing interests of oncologists in lung cancer field. Although multiple anti-cancer mechanisms of cardiac glycosides as Na(+)/K(+)-ATPase inhibitors are revealed, the role of autophagy and related molecular signaling pathway for the class of compounds in human non-small cell lung cancer (NSCLC) cells has not been systematically examined. We herein investigated the anti-cancer effects of two representative cardiac glycosides, digoxin and ouabain, in A549 and H460 cell lines. Both agents caused significant growth inhibition at nanomolar level. The cardiac glycosides were found to induce moderate G(2)/M arrest but not apoptosis at IC(50) level in the NSCLC cell lines. Moreover, autophagy was markedly induced by both agents, as evidenced by the time- and dose-dependent increase of LC3-II, up-regulation of Atg5 and Beclin1, as well as by the observations through acridine orange staining, transmission electron microscopy and quantification of GFP-LC3 fluorescence. Importantly, AMP-activated protein kinase (AMPK) pathway was activated, resulting in mammalian target of rapamycin (mTOR) deactivation during autophagy induction. Moreover, extracellular-signal-regulated kinase 1/2 (ERK1/2) activation was simultaneously found to be involved in the autophagy regulation. Co-treatment with respective inhibitors or siRNAs could either block the autophagic phenotypes and signals, or significantly increase the cellular viability, indicating the drugs-induced autophagy plays tumor-suppressing role. This work provides first evidence showing that the cardiac glycosides induce autophagy in human NSCLC cells through regulation of both mTOR and ERK1/2 signaling pathways. The autophagy may at least partially account for the growth inhibitory effects of the compounds in human NSCLC cells.

Circadian clock manipulation for cancer prevention and control and the relief of cancer symptoms

Life has evolved on this planet with regular daily spans of direct solar energy availability alternating with nocturnal spans of dark. Virtually every earth-borne life form has factored this circadian pattern into its biology to ensure the temporal coordination with its resonating environment, a task essential for its individual survival and that of its species. The first whole genome inspections of mutations in human colon and breast cancer have observed specific retained clock gene mutations. Single nucleotide polymorphisms within the genes of clock, clock-controlled, and melatonin pathways have been found to confer excess cancer risk or protection from cancer. Experimental studies have shown that specific core clock genes (Per2 and Per1) are tumor suppressors because their genetic absence doubles tumor numbers, and decreasing their expression in cancer cells doubles cancer growth rate, whereas their overexpression decreases cancer growth rate and diminishes tumor numbers. Experimental interference with circadian clock function increases cancer growth rate, and clinical circadian disruption is associated with higher cancer incidence, faster cancer progression, and shorter cancer patient survival. Patients with advanced lung cancer suffering greater circadian activity/sleep cycle disruption suffer greater interference with function, greater anxiety and depression, poorer nighttime sleep, greater daytime fatigue, and poorer quality of life than comparable patients who maintain good circadian integration. We must now determine whether strategies known to help synchronize the circadian clocks of normal individuals can do so in advanced cancer patients and whether doing so allows cancer patients to feel better and/or live longer. Several academic laboratories and at least 2 large pharmaceutical firms are screening for small molecules targeting the circadian clock to stabilize its phase and enhance its amplitude and thereby consolidate and coordinate circadian organization, which in turn is likely to help prevent and control human cancer. These drugs and strategies can, in turn, be used to make cancer patients with advanced disease feel and function more normally.

Expression of epidermal growth factor receptor, but not K-RAS mutations, is present in congenital cystic airway malformation/congenital pulmonary airway malformation

Congenital cystic airway malformation/congenital pulmonary airway malformation (CCAM/CPAM) of the lung is a rare but well-described malformative lesion of pulmonary parenchyma characterized by the abnormal maturation of airways along with an increase in terminal respiratory structures, resulting in cysts of variable sizes. Five types have been classified based on morphological analysis. Although the etiology of the lesion is still unclear, recent data suggest that bronchial atresia is a predisposing/associated anomaly. A described association between type 1 CCAM/CPAM and bronchioloalveolar carcinoma suggests that type 1 CCAM/CPAM may predispose to malignant transformation by as yet unidentified tumorigenic mechanisms. Here we studied epidermal growth factor receptor (EGFR) and K-RAS oncogene, 2 biological markers closely associated with tumorigenesis and altered in many types of tumors, including lung carcinomas. For this purpose, we used immunohistochemistry and gene sequencing in paraffin-embedded tissue. Our results demonstrate expression of EGFR in types 1 and 3 CCAM/CPAM, with a distinctive distribution and intensity, compared with that of type 2. Of special interest, mucinous areas in 2 cases of type 1 CCAM/CPAM lacked EGFR expression, whereas adjacent epithelial cystic linings were strongly positive. This supports the hypothesis that mucinous differentiation in CCAM/CPAM, always present in cases with malignant transformation, could be related to other molecular pathways. The K-RAS gene was screened for mutations usually found in lung carcinomas; however, no mutations were present in any of the studied samples. These findings support the notion that EGFR may play an important role in the pathogenesis and phenotype of CCAM/CPAM.

Interaction Index and Different Methods for Determining Drug Interaction in Combination Therapy

Studying and understanding the joint effect of combined treatments is important in pharmacology and in the development of combination therapies. The Loewe additivity model is one of the best general reference models for evaluating drug interactions. Based on this model, synergy occurs when the interaction index is less than one, while antagonism occurs when interaction index is greater than one. We expanded the meaning of the interaction index, and propose a procedure to calculate the interaction index and its associated confidence interval under the assumption that the dose-effect curve for a single agent follows Chou and Talalay's median effect equation. In addition, we review four response surface models based on the Loewe additivity model using a single parameter to determine drug interactions. We describe each of these models in the context of Loewe additivity model and discuss their relative advantages and disadvantages. We also provide S-PLUS/R code for each approach to facilitate the implementation of these commonly used methods.

Erlotinib: small-molecule targeted therapy in the treatment of non-small-cell lung cancer

BACKGROUND

Erlotinib is an oral tyrosine kinase inhibitor, targeting the human epidermal receptor type 1/ epidermal growth factor receptor, recently approved by the US Food and Drug Administration (FDA) for the treatment of patients with locally advanced or metastatic non-small-cell lung cancer (NSCLC) after the failure of more than 1 or 2 previous chemotherapeutic regimens.

OBJECTIVE

The purpose of this article is to summarize the development, pharmacology, pharmacokinetics, efficacy, and adverse effects of erlotinib.

METHODS

A literature search was conducted with the MEDLINE and EMBASE (1999-2005) databases using the search terms non-small-cell lung cancer, erlotinib, and epidermal growth factor receptor inhibitor. Abstracts from the American Society of Clinical Oncology and documents submitted to the FDA also were reviewed.

RESULTS

BR.21, a randomized, placebo-controlled, multinational Phase III trial demonstrated clinically and statistically improved overall survival in patients with advanced or metastatic NSCLC treated with erlotinib versus placebo as second-line therapy. The erlotinib group had a median survival of 6.7 months versus a median survival of 4.7 months in the placebo group (P < 0.001). The toxicity profile of erlotinib was moderately benign, with the most commonly documented adverse events requiring dose reductions including skin rash (12%) and diarrhea (5%). Interstitial lung disease and relative fatalities were reported infrequently (0.8%) in patients receiving erlotinib. Two randomized, placebo-controlled, multicenter Phase III trials conducted in patients with locally advanced and metastatic NSCLC showed no clinical benefit with first-line administration of erlotinib plus concurrent platinum-based chemotherapy.

CONCLUSIONS

For patients with NSCLC in whom more than 1 or 2 previous chemotherapeutic regimens have failed, erlotinib is an effective therapy with significant overall survival benefits. The use of erlotinib as first-line therapy in combination with platinum-based chemotherapeutic regimens, however, has failed to demonstrate efficacy in the treatment of NSCLC.

Circadian function in patients with advanced non-small-cell lung cancer

This study aimed to evaluate whether patients with advanced non-small-cell lung cancer experience disrupted rest–activity daily rhythms, poor sleep quality, weakness, and maintain attributes that are linked to circadian function such as fatigue. This report describes the rest–activity patterns of 33 non-small-cell lung cancer patients who participated in a randomised clinical trial evaluating the benefits of melatonin. Data are reported on circadian function, health-related quality of life (QoL), subjective sleep quality, and anxiety/depression levels prior to randomisation and treatment. Actigraphy data, an objective measure of circadian function, demonstrated that patients' rest–activity circadian function differs significantly from control subjects. Our patients reported poor sleep quality and high levels of fatigue. Ferrans and Powers QoL Index instrument found a high level of dissatisfaction with health-related QoL. Data from the European Organization for Research and Treatment for Cancer reported poor capacity to fulfil the activities of daily living. Patients studied in the hospital during or near chemotherapy had significantly more abnormal circadian function than those studied in the ambulatory setting. Our data indicate that measurement of circadian sleep/activity dynamics should be accomplished in the outpatient/home setting for a minimum of 4–7 circadian cycles to assure that they are most representative of the patients' true condition. We conclude that the daily sleep/activity patterns of patients with advanced lung cancer are disturbed. These are accompanied by marked disruption of QoL and function. These data argue for investigating how much of this poor functioning and QoL are actually caused by this circadian disruption, and, whether behavioural, light-based, and or pharmacologic strategies to correct the circadian/sleep activity patterns can improve function and QoL.

Increases of amphiregulin and transforming growth factor-alpha in serum as predictors of poor response to gefitinib among patients with advanced non-small cell lung cancers

Serum levels of amphiregulin and transforming growth factor-alpha (TGF-alpha), which were identified previously to be expressed at high levels in non-small cell lung cancer (NSCLC) with poor response to gefitinib, were examined by ELISA using blood samples taken from 50 patients with advanced NSCLCs. Of 14 cases that revealed above the cutoff line for amphiregulin in serum, 12 responded poorly to gefitinib, whereas 18 of the 36 cases showing below the cutoff revealed partial response (PR) or stable disease (SD; P = 0.026). Thirteen of 15 patients who were positive for TGF-alpha responded poorly to gefitinib, whereas 18 of the 35 patients with negative TGF-alpha levels turned out to be relatively good responders (P = 0.014). Of 22 patients with positive values for either or both markers, 19 were poor responders. On the other hand, among 28 patients negative for both markers, 17 were classified into the PR or SD groups (P = 0.001). Gefitinib-treated NSCLC patients whose serum amphiregulin or TGF-alpha was positive showed a poorer tumor-specific survival (P = 0.037 and 0.002, respectively, by univariate analysis) compared with those whose serum amphiregulin or TGF-alpha concentrations were negative. Multivariate analysis showed an independent association between positivity for TGF-alpha and shorter survival times among NSCLC patients treated with gefitinib (P = 0.034). Amphiregulin or TGF-alpha positivity in NSCLC tissues was significantly higher in male, nonadenocarcinomas, and smokers. Our data suggest that the status of amphiregulin and TGF-alpha in serum can be an important predictor of the resistance to gefitinib among patients with advanced NSCLC.

Myocarditis temporally related to the use of gefitinib (Iressa)

Gefitinib is a new drug that was approved by the US Food and Drug Administration in May 2003 for non-small cell cancer of the lung refractory to first- and second-line therapy. It is regarded as a rather safe drug with common adverse effects that include nausea, vomiting, diarrhea, rash, acne, and dry skin. However, it was reported in Japan to be associated with interstitial pneumonitis (2%-3% of subjects), presumably as a manifestation of a hypersensitivity reaction. The Food and Drug Administration studied this in US patients and found only a 0.3% occurrence and a slightly less than 0.1% mortality due to interstitial pneumonitis. To our knowledge, there has not been an association with fulminant myocarditis or acute myocarditis. We report the case of a 71-year-old man who died as a result of fulminant myocarditis 1 week after starting to take this new class of agent, gefitinib. On the basis of his medical history and our findings, we feel it necessary to consider hypersensitivity myocarditis related to gefitinib the probable cause of death.

EGFR mutations in non-small-cell lung cancer: analysis of a large series of cases and development of a rapid and sensitive method for diagnostic screening with potential implications on pharmacologic treatment

PURPOSE

It has been reported that EGFR mutations in lung carcinomas make the disease more responsive to treatment with tyrosine kinase inhibitors. We decided to evaluate the prevalence of EGFR mutations in a large series of non-small-cell lung carcinomas (NSCLCs) and to develop a rapid and sensitive screening method. PATIENTS AND METHODS We examined 860 consecutive NSCLC patients for EGFR mutations in exons 18, 19, and 21 using a dual technical approach--direct sequencing of polymerase chain reaction (PCR) products and PCR single-strand conformation polymorphism (SSCP) analysis. Moreover, all lung adenocarcinomas were analyzed for K-ras mutations at codon 12 by allele-specific oligoprobe hybriditations.

RESULTS

There were no EGFR mutations in 454 squamous carcinomas and 31 large cell carcinomas investigated. Thirty-nine mutations were found in the series of 375 adenocarcinomas (10%). Mutations were present in 26% of 86 bronchioloalveolar carcinomas (BACs) and in 6% of 289 conventional lung adenocarcinomas; P = .000002. EGFR mutations and K-ras mutations were mutually exclusive. A multivariable analysis revealed that BAC histotype, being a never smoker, and female sex were independently associated with EGFR mutations (odds ratios: 4.542, 3.632, and 2.895, respectively). The SSCP analysis was accurate and sensitive, allowing identification of mutations that were undetectable (21% of cases) by direct sequencing.

CONCLUSION

Mutations in the EGFR tyrosine kinase domain define a new molecular type of lung carcinoma, more frequent in particular subsets of patients. The SSCP assay is a rapid and reliable method for the detection of EGFR kinase domain mutations in lung cancer.