Aims:
Lung cancer is one of the most heterogeneous of all solid cancers. This may in part be due to hi-jacking and additional bystander affects that are exerted on the normal lung cell population by the cancer cells. A number of pathways may be stimulated through soluble factors or effector filled vesicles such as exosomes secreted by cancer cells. The aim of this project was to evaluate the effects of non-small cell lung cancer (NSCLC) cells on an immortalised normal bronchial epithelial cell line.
Methods:
A normal bronchial epithelial cell line (HBEC4) was exposed to adenocarcinoma, large cell and squamous NSCLC cell lines and a number of phenotypic and genotypic characterisations were undertaken. These included cellular proliferation (BrdU ELISA), gene (RT-PCR) and miRNA expression screening (Nanostring). The effect of cancer exosome fractions was also determined.
Results:
Exposure to various subtypes of NSCLC significantly increased the cellular proliferation rate of the immortalised cell line in a number of models. Expression of a number of miRNAs was altered in the normal cells pre- and post exposure to the cancer cells. Various stem cell factor markers (KLF4, Oct, c-myc) were also significantly changed at the mRNA level. In addition, exosome fractions altered the behaviour of the normal cell line, likewise stimulating cell proliferation.
Conclusions:
Lung cancer cells may influence normal cell behaviour in both a direct and indirect manner using multiple mechanisms. Normal bronchial epithelial cells with stem like features may be induced to proliferate and behave in a malignant manner. This, akin to Hodgkin’s lymphoma, may contribute significantly to the composition of the tumour. Furthermore this observation may contribute to the heterogeneity of lung cancer tumours and affect treatment response. Ongoing studies are evaluating these effects in 2D and novel 3D culture systems.