Citations

Abstract Protein kinase C (PKC) isozymes have long been implicated in carcinogenesis. However, little is known about the functional significance of these enzymes in human cancer. We recently showed that the atypical PKC (aPKC) isozyme PKCι is overexpressed in human non–small cell lung cancer (NSCLC) cells and that PKCι plays a critical role in the transformed growth of the human lung adenocarcinoma A549 cell line in vitro and tumorigenicity in vivo. Here we provide compelling evidence that PKCι is an oncogene in NSCLC based on the following criteria: (a) aPKCι is overexpressed in the vast majority of primary NSCLC tumors; (b) tumor PKCι expression levels predict poor survival in patients with NSCLC; (c) the PKCι gene is frequently amplified in established NSCLC cell lines and primary NSCLC tumors; (d) gene amplification drives PKCι expression in NSCLC cell lines and primary NSCLC tumors; and (e) disruption of PKCι signaling with a dominant negative PKCι allele blocks the transformed growth of human NSCLC cells harboring PKCι gene amplification. Taken together, our data provide conclusive evidence that PKCι is required for the transformed growth of NSCLC cells and that the PKCι gene is a target for tumor-specific genetic alteration by amplification. Interestingly, PKCι expression predicts poor survival in NSCLC patients independent of tumor stage. Therefore, PKCι expression profiling may be useful in identifying early-stage NSCLC patients at elevated risk of relapse. Our functional data indicate that PKCι is an attractive target for development of novel, mechanism-based therapeutics to treat NSCLC.

Abstract Purpose: Akt is a signal transduction protein that plays a central role in inhibiting apoptosis in a variety of cell types including human cancer cells. In cell lines derived from human non–small cell lung cancers (NSCLCs), Akt has been shown to confer chemoresistance by inhibition of apoptosis in response to different chemotherapeutic agents including platinum-based agents, which are often the first-line therapy for NSCLCs. Only 20% to 30% of patients with NSCLC treated with chemotherapy have clinical evidence of response. The purpose of this study is to determine whether or not overexpression of activated Akt [i.e., phosphorylated Akt (pAkt)] is correlated with survival. Experimental Design: We studied tumors from 61 patients with NSCLC in three tissue microarrays. All patients were followed for a period of 10 years or until death. The arrays were studied immunohistochemically with antibodies against pAkt, p53, and Ki-67. Results: There was a statistically significant difference in survival between the 14 patients with strong pAkt staining and the 47 patients with weak to absent pAkt staining both by log-rank (P = 0.0416) and Breslow analysis (P = 0.0446). Difference in survival time with respect to pAkt status was also statistically significant even after accounting for stage at diagnosis (P = 0.004). Neither p53 nor Ki-67 was a statistically significant prognostic factor. Conclusions: Overexpression of pAkt is an independent prognostic factor. Additional studies of human NSCLCs are warranted to drive the development of targeted tumor-specific antineoplastic therapies.

Abstract Past lung cancer screening trials in the United States with chest X-ray and sputum cytology were not able to show any decrease in lung cancer mortality; however, these trials are over 20 years old. Recent follow-up of the Mayo Lung Project showed a better survival from lung cancer in the screened arm, but no difference in overall mortality, suggesting an overdiagnosis of nonfatal cancers. Recent reports of low radiation dose spiral computed tomography (CT) chest screening for lung cancer have shown that CT screening detects cancers at a smaller size than chest X-rays. To date, there have been no randomized trials of CT versus observation or chest radiographs for screening purposes. All data available thus far on CT screening are from phase II proof-of-principle trials. The major limitations of CT screening, discussed here, include (a) a high rate of nodule detection: over 50% of participants will have at least one noncalcified nodule; (b) resulting follow-up CT scans, associated with increased costs; (c) cost and morbidity of biopsy or resection of benign noncalcified nodule (20-25% of such procedures in several trials); and (d) a small, but difficult to quantify, risk of cancer associated with multiple follow-up CT scans.

Abstract We evaluated somatic genetic alterations in the kinase domain of the EGFR gene in the tumors of 219 non–small cell lung cancer patients of primarily Caucasian and African American origins. We identified 26 patients (12%) whose tumors had a mutation in the EGFR gene, and 11 (5%) patients carried novel genomic variations consistent with germ-line polymorphisms. All but one mutation were identified in Caucasian patients affected with adenocarcinoma. EGFR mutations were more frequent in women and in nonsmokers, but a significant portion of the affected patients were men (12 of 26) and current or past smokers accounted for half of the patients affected (13 of 26). Screening subjects with EGFR mutations may identify patients whose tumors could respond to targeted therapy using tyrosine kinase inhibitors.

Purpose A randomized three-arm phase II study was undertaken to evaluate the optimum administration schedule of pemetrexed and gemcitabine in chemotherapy-naïve patients with non–small-cell lung cancer. Patients and Methods Patients were randomly assigned to three schedules of pemetrexed 500 mg/m2 plus gemcitabine 1,250 mg/m2, separated by a 90-minute interval, on a 21-day cycle as follows: schedule A, pemetrexed followed by gemcitabine on day 1 and gemcitabine on day 8; schedule B, gemcitabine followed by pemetrexed on day 1 and gemcitabine on day 8; and schedule C, gemcitabine on day 1 and pemetrexed followed by gemcitabine on day 8. Results One hundred fifty-two eligible patients (schedule A, n = 59; schedule B, n = 31, and schedule C, n = 62) received a median of five (schedule A), two (schedule B), and four (schedule C) treatment cycles. Overall, 66% of patients experienced grade 3 or 4 neutropenia. Common grade 3 and 4 nonhematologic toxicities were dyspnea (11%), fatigue (16%), and transaminase elevation (9%). Schedule A seemed less toxic compared with schedule C (grade 3 or 4 events: 86% v 94%, respectively; P = .19; grade 4 events: 39% v 48%, respectively; P = .30). Schedule B was closed at interim analysis for inferior efficacy. Schedule A, with a confirmed response rate of 31% (95% CI, 20% to 45%), met the protocol-defined efficacy criteria, whereas schedule C, with a confirmed response rate of 16.1% (95% CI, 11% to 34%), did not. Median survival time and time to progression were 11.4 and 4.4 months, respectively, with no observable difference between the arms. Conclusion Pemetrexed and gemcitabine administered as outlined for schedule A met the protocol-defined efficacy criteria, was less toxic compared with the other treatment schedules, and should be further evaluated.

Abstract Rationale Phenotypic and genotypic heterogeneity of lung cancer likely precludes the identification of a single predictive marker and suggests the importance of identifying and measuring multiple markers. Objectives We describe the use of a fluorescent protein microarray to identify and measure multiple non–small cell lung cancer–associated antibodies and show how simultaneous measurements can be combined into a single diagnostic assay. Methods T7 phage cDNA libraries of non–small cell lung cancer were first biopanned with plasma samples from normal subjects and patients with non–small cell lung cancer to enrich the component of tumor-associated proteins, and then applied to microarray slides. Two hundred twelve immunogenic phage-expressed proteins were identified from roughly 4,000 clones, using high-throughput screening with patient plasmas and assayed with 40 cancer and 41 normal plasma samples. Twenty patient and 21 normal plasma samples were randomly chosen and used for statistical determination of the predictive value of each putative marker. Statistical analysis identified antibody reactivity to seven unique phage-expressed proteins that were significantly different (p < 0.01) between patient and normal groups. The remaining 20 patient and 20 normal plasma samples were used as an independent test of the predictive ability of the selected markers. Main Results Measurements of the 5 most predictive phage proteins were combined in a logistic regression model that achieved 90% sensitivity and 95% specificity in prediction of patient samples, whereas leave-one-out statistical analysis achieved 88.9% diagnostic accuracy among all 81 samples. Conclusion Our data indicate that antibody profiling is a promising approach that could achieve high diagnostic accuracy for non–small cell lung cancer.

Purpose To determine, in a randomized comparison, whether the addition of paclitaxel to etoposide and cisplatin improves the time to progression and overall survival in patients with extensive small-cell lung cancer (SCLC) compared with standard etoposide and cisplatin and to compare the regimens' toxicity. Patients and Methods Eligible patients (N = 587) with untreated extensive SCLC were randomly assigned to receive either cisplatin 80 mg/m2 on day 1 and etoposide 80 mg/m2 on days 1 through 3 administered every 3 weeks for six cycles (EP) or cisplatin 80 mg/m2 on day 1, paclitaxel 175 mg/m2 over 4 hours on day 1, and etoposide 80 mg/m2 on days 1 to 3 followed by recombinant human granulocyte colony-stimulating factor on days 4 to 18 administered every 3 weeks for six cycles (PET). Results Reporting of demographics, response, and survival included 565 patients, of whom 282 were randomly assigned to receive EP and 283 were assigned to receive PET. Overall response rates were 68% for the EP arm and 75% for the PET arm. Median failure-free survival time was 5.9 months for the EP arm and 6 months for the PET arm (P = .179). Median overall survival time was 9.9 months for patients on EP and 10.6 months for patients on PET (P = .169). Toxic deaths occurred in 2.4% of the patients on EP and 6.5% of patients on PET. Conclusion PET did not improve the time to progression or survival in patients with extensive SCLC compared with EP alone and was associated with unacceptable toxicity.

Previous studies in native tissues have produced conflicting data on the localization and metabolic fate of WT and ΔF508 cystic fibrosis transmembrane regulator (CFTR) in the lung. Combining immunocytochemical and biochemical studies utilizing new high-affinity CFTR mAbs with ion transport assays, we examined both 1) the cell type and region specific expression of CFTR in normal airways and 2) the metabolic fate of ΔF508 CFTR and associated ERM proteins in the cystic fibrosis lung. Studies of lungs from a large number of normal subjects revealed that WT CFTR protein localized to the apical membrane of ciliated cells within the superficial epithelium and gland ducts. In contrast, other cell types in the superficial, gland acinar, and alveolar epithelia expressed little WT CFTR protein. No ΔF508 CFTR mature protein or function could be detected in airway specimens freshly excised from a large number of ΔF508 homozygous subjects, despite an intact ERM complex. In sum, our data demonstrate that WT CFTR is predominantly expressed in ciliated cells, and ΔF508 CFTR pathogenesis in native tissues, like heterologous cells, reflects loss of normal protein processing.