Epidermal Growth Factor Receptor Inhibitors, Gefitinib and Erlotinib (Tarceva™, OSI-774), in the Treatment of Bronchioloalveolar Carcinoma

EGFR-targeted plasmonic magnetic nanoparticles suppress lung tumor growth by abrogating G2/M cell-cycle arrest and inducing DNA damage

Background

We have previously demonstrated the epidermal growth factor receptor (EGFR)-targeted hybrid plasmonic magnetic nanoparticles (225-NP) produce a therapeutic effect in human lung cancer cell lines in vitro. In the present study, we investigated the molecular mechanism of 225-NP-mediated antitumor activity both in vitro and in vivo using the EGFR-mutant HCC827 cell line.

Methods

The growth inhibitory effect of 225-NP on lung tumor cells was determined by cell viability and cell-cycle analysis. Protein expression related to autophagy, apoptosis, and DNA-damage were determined by Western blotting and immunofluorescence. An in vivo efficacy study was conducted using a human lung tumor xenograft mouse model.

Results

The 225-NP treatment markedly reduced tumor cell viability at 72 hours compared with the cell viability in control treatment groups. Cell-cycle analysis showed the percentage of cells in the G2/M phase was reduced when treated with 225-NP, with a concomitant increase in the number of cells in Sub-G1 phase, indicative of cell death. Western blotting showed LC3B and PARP cleavage, indicating 225-NP-treatment activated both autophagy- and apoptosis-mediated cell death. The 225-NP strongly induced γH2AX and phosphorylated histone H3, markers indicative of DNA damage and mitosis, respectively. Additionally, significant γH2AX foci formation was observed in 225-NP-treated cells compared with control treatment groups, suggesting 225-NP induced cell death by triggering DNA damage. The 225-NP-mediated DNA damage involved abrogation of the G2/M checkpoint by inhibiting BRCA1, Chk1, and phospho-Cdc2/CDK1 protein expression. In vivo therapy studies showed 225-NP treatment reduced EGFR phosphorylation, increased γH2AX foci, and induced tumor cell apoptosis, resulting in suppression of tumor growth.

Conclusion

The 225-NP treatment induces DNA damage and abrogates G2/M phase of the cell cycle, leading to cellular apoptosis and suppression of lung tumor growth both in vitro and in vivo. Our findings provide a rationale for combining 225-NP with other DNA-damaging agents for achieving enhanced anticancer activity.

Ultrasound-promoted synthesis and immunosuppressive activity of novel quinazoline derivatives

An environmentally friendly and mild Bischler cyclization was developed to access quinazolines with diverse substitution. Based on this method, a library of 53 quinazoline derivatives was prepared and tested in vitro for cytotoxicity and inhibition on T-cell and B-cell proliferation. Compounds 6b, 7b, 17b, 33, and 35 showed higher inhibitory activity on both T-cell and B-cell proliferations, with IC(50) values of 6.16, 6.30, 5.43, 2.54, and 9.80 μM on T-cell, respectively. All the tested compounds showed no obvious cytotoxicity at 10 μM concentration. The preliminary structure-activity relationship was concluded revealing that 4-position is the key modification site for potent quinazoline immunosuppressive agent.

EGFR-targeted hybrid plasmonic magnetic nanoparticles synergistically induce autophagy and apoptosis in non-small cell lung cancer cells

BACKGROUND

The epidermal growth factor receptor (EGFR) is overexpressed in 80% of non-small cell lung cancer (NSCLC) and is associated with poor survival. In recent years, EGFR-targeted inhibitors have been tested in the clinic for NSCLC. Despite the emergence of novel therapeutics and their application in cancer therapy, the overall survival rate of lung cancer patients remains 15%. To develop more effective therapies for lung cancer we have combined the anti-EGFR antibody (Clone 225) as a molecular therapeutic with hybrid plasmonic magnetic nanoparticles (NP) and tested on non-small cell lung cancer (NSCLC) cells.

METHODOLOGY/PRINCIPAL FINDINGS

Cell viability was determined by trypan-blue assay. Cellular protein expression was determined by Western blotting. C225-NPs were detected by electron microscopy and confocal microscopy, and EGFR expression using immunocytochemistry. C225-NP exhibited a strong and selective antitumor effect on EGFR-expressing NSCLC cells by inhibiting EGFR-mediated signal transduction and induced autophagy and apoptosis in tumor cells. Optical images showed specificity of interactions between C225-NP and EGFR-expressing NSCLC cells. No binding of C225-NP was observed for EGFR-null NSCLC cells. C225-NP exhibited higher efficiency in induction of cell killing in comparison with the same amount of free C225 antibody in tumor cells with different levels of EGFR expression. Furthermore, in contrast to C225-NP, free C225 antibody did not induce autophagy in cells. However, the therapeutic efficacy of C225-NP gradually approached the level of free antibodies as the amount of C225 antibody conjugated per nanoparticle was decreased. Finally, attaching C225 to NP was important for producing the enhanced tumor cell killing as addition of mixture of free C225 and NP did not demonstrate the same degree of cell killing activity.

CONCLUSIONS/SIGNIFICANCE

We demonstrated for the first time the molecular mechanism of C225-NP induced cytotoxic effects in lung cancer cells that are not characteristic for free molecular therapeutics thus increasing efficacy of therapy against NSCLC.

Initial treatment strategies and outcomes for multifocal bronchioloalveolar carcinoma

BACKGROUND

Bronchioloalveolar carcinoma (BAC) commonly presents as multifocal disease. Management of multifocal BAC remains controversial and may include surgical resection, systemic therapy, surveillance, or a combination of these strategies. Knowledge of current practice patterns and outcomes could help to inform future research.

MATERIALS AND METHODS

Medical records of patients with BAC were retrospectively reviewed, and regression analyses were conducted to correlate demographic parameters, disease characteristics, and treatment modality with clinical outcomes.

RESULTS

Of the 109 cases identified, 85 patients were eligible for study, 26% with unifocal and 74% with multifocal BAC. Median age at diagnosis was 65 years; the majority of the patients were female (64%), were non-Asian (82%), and had a smoking history (66%). In the subset with multifocal BAC, 24% of the cases were confined to one lobe, 76% affected multiple lobes, and 40% involved both lungs. The primary treatment modality for multifocal disease included surgical resection (78%), systemic therapy (14%), and observation (8%). In multivariate analyses, extensive disease (> or = 3 lobes involved) and medical oncology assessment predicted treatment with systemic therapy (odds ratio [OR], 8.68; P = .03 and OR, 1.68; P < .01, respectively). The presence of extensive disease and the receipt of systemic therapy were associated with higher likelihood of disease progression (hazard ratio [HR], 8.62; P = .02 and HR, 8.46; P = .02, respectively).

CONCLUSION

Initial treatment choices and referral patterns for multifocal BAC were diverse and influenced by clinical selection, whereby patients with extensive disease were more likely to discuss and receive systemic therapy. Surgery and surveillance were reasonable treatment options for selected patients. The precise roles of the various treatment strategies for multifocal BAC require further evaluation.

Novel effects of gefitinib on mucin production in bronchioloalveolar carcinoma; two case reports

Two Japanese females complained of cough and bronchorrhea for which chest radiographs showed infiltrate in the lungs. The patients were subsequently diagnosed as having bronchioloalveolar carcinoma by transbronchial lung biopsy. After receiving systemic chemotherapy, their symptoms were slightly improved. A few months later, their bronchorrhea and dyspnea worsened, and they were then treated with gefitinib, a selective epidermal growth factor receptor tyrosine kinase inhibitor. Bronchorrhea and dyspnea were improved within 24 h after treatment with gefitinib where the improvement was evident after 6 h for one patient and 24 h for the other patient. Thereafter, their radiological findings showed gradual improvement. Rapid relief of bronchorrhea preceded the improvement seen by the radiological findings. These observations suggest that gefitinib may inhibit mucin production as well as exert anti-proliferative activity against bronchioloalveolar carcinoma.