Gene therapy for lung cancer

Evaluation of the Spatial Diffusion of Methylene Blue Injected in vivo by Bronchoscopy into Non-Small Cell Lung Carcinoma

BACKGROUND

Due to smoking prevalence and the poor efficiency of current therapy, lung cancer is the leading cause of cancer death in developed countries, and its worldwide incidence is steadily increasing. Gene therapy by direct intratumoral injection of different types of gene constructs through a fiberscope has been suggested and evaluated in a few patients.

OBJECTIVE

It was the aim of this study to observe the actual volume of diffusion within a lung tumor using a color marker.

METHODS

Using bronchoscopy, just after anesthesia, methylene blue was injected into patient tumors. These patients subsequently underwent surgery for treatment of a non-small cell lung cancer.

RESULTS

We observed a diffusion of methylene blue in resected lung tumors with a mean infiltrated versus noninfiltrated tumor volume ratio of 29 +/- 15%. Interestingly, some large tumor areas were not stained. At the cellular level, a preferential diffusion of the dye was observed in the tumor stroma compartment versus the tumor cellular compartment, where basal cells were more frequently and strongly labeled than the other tumor cells.

CONCLUSIONS

Since a cancer is cured when most, if not all, cancer cells are killed, the preliminary evaluation of the spatial diffusion of any injected gene construct should be carried out as a first step in any cancer type.

Coxsackievirus and adenovirus receptor expression in non-malignant lung tissues and clinical lung cancers

Adenoviral vector mediated gene delivery has been applied in clinical trials and mechanistic studies to explore new treatment approaches for lung cancers. The expression of coxsackievirus adenovirus receptor (CAR), the primary receptor for the most commonly used adenovirus serotype 5 (Ad5)-based vectors, predominantly determines the permissiveness of lung cancer cells. CAR expression is also suggested to modulate tumor cell proliferation capacity. Here, we studied CAR expression in archival lung cancer specimens by using well-characterized CAR 72 antibodies. High levels of CAR expression were observed in most of the 32 cases of squamous cell carcinoma lung cancers and in all the five cases of small cell lung cancers investigated. In contrast, high levels of CAR expression were detected only in 6 of 22 adenocarcinoma lung cancers. The relative levels of CAR expression did not correlate with the pathologic grade in lung cancers, and was thus inconsistent with a role of modulating cancer cell proliferation. Of note, CAR expression was not detected in non-malignant alveolar cells. Our data suggest a preferred utility of Ad5 vector mediated gene delivery to squamous cell carcinoma lung cancers, small cell lung cancers, but not to the majority of adenocarcinoma lung cancers.