Identification of genes expressed differentially in an in vitro human lung carcinogenesis model

Abstract

Lung cancer is the deadliest among all cancers in the US for both men and women. Early detection of premalignant lesions or tumors appears to be a promising approach to reducing the morbidity and mortality from lung cancer because the survival of early stage lung cancer patients is better than that of patients with advanced cancers. We approached the identification of early biomarkers of human lung carcinogenesis, by combining the use of cDNA array and an in vitro human lung carcinogenesis model that consists of normal (NHBE), immortalized (BEAS-2B and 1799), transformed (1198) and tumorigenic (1170-I) human bronchial epithelial (HBE) cells. We hypothesized that certain genes that are expressed differentially among these cells can serve as both biomarkers for early detection and targets for intervention. Nineteen genes were downregulated and six were upregulated in tumorigenic 1170-I HBE cells compared to normal HBE cells (NHBE) using cDNA array. Downregulated genes encode cell-to-cell and cell-to-matrix adhesion-related proteins, calcium-binding proteins and some enzymes or growth factor-related proteins. The functions of upregulated gene were more variable. Similar expression of selected genes was found in different nonsmall cell lung cancer cell lines analyzed by Northern blotting. Furthermore, the differential expression of some genes was also observed by in silico analysis of database of human lung tumors. The differentially expressed genes encode calcium-binding proteins and cell-cell and cell-matrix adhesion proteins. Furthermore, Northern blotting analysis of RNA from different cell lines comprising an in vitro carcinogenesis model including normal, immortalized, transformed, and tumorigenic cells indicated that the expression of subsets of the identified genes changed at different stages of carcinogenesis. These data show that the in vitro carcinogenesis cell system could be useful for discovering potential biomarkers of early and late stages of lung carcinogenesis and targets for chemoprevention.

Expression of the Receptor Tyrosine Kinase EphA2 Is Increased in Smokers and Predicts Poor Survival in Non–Small Cell Lung Cancer

“…Calnexin was used as a loading control. The table shows how the cell lines in the in vitro carcinogenesis model were developed and characterized (20,25). CSC, cigarette smoke condensate.…”

“…NSCLC cells were obtained from the American Type Culture Collection and grown as monolayer cultures in RPMI 1640 containing 10% fetal bovine serum and 2 mmol/L glutamine at 37jC in a humidified atmosphere with 5% CO 2 . BS2B, 1799, 1197, and 1170-I cells were derived as previously described (20) and grown in keratinocyte serum-free medium containing bovine pituitary extract and either EGF (BS2B and 1799) or 3% fetal bovine serum (1198 and 1170-I) at 37jC in a humidified chamber with 5% CO 2 (21), and selected for construction of a TMA. To address tumor heterogeneity, we used tissue specimens from three different areas of the tumor (center, periphery, and intermediate) when constructing the TMAs.…”

Identification of Gene Signatures and Molecular Markers for Human Lung Cancer Prognosis using anIn vitroLung Carcinogenesis System

“…It is also noteworthy that a previously identified SV40 T/t-Antigen cancer gene signature, developed and integrated from mouse models, was highly evident in the gene expression patterns of clinical samples of human breast, prostate, and lung cancers and was significantly associated with poor prognosis in these tumors (38). Moreover, we have previously validated aberrant gene expression within the vitro system we used at the mRNA level in 11 established NSCLC cell lines and at the protein level in clinical NSCLC samples (39, 40). In this much more comprehensive study using more advanced technology, we further established that this particular cell system provides a powerful tool to predict outcomes of NSCLC cancers and aids in the exploration of the molecular mechanisms of lung carcinogenesis that could be translated into both chemoprevention and treatment of lung cancer.…”

Identification of potential lung cancer biomarkers using an in vitro carcinogenesis model

“…Although identification of differentially expressed genes in the human lung carcinogenesis model using cDNA microarray techniques has been previously reported (Feng et al, 2001;Lacroix et al, 2006), this is the first time, to our knowledge, that the differential secretion of proteins has been investigated in this model. We successfully demonstrated that PGP9.5, TCTP, TIMP-2, and TPI were differentially secreted from both transformed 1198 and 1170-I cells, and were present in significantly high concentrations in plasmas and tissue samples of lung cancer patients.…”