This detection method was used to detect mRNA heterogeneous nuclear ribonucleoproteins (hnRNP B1) in two cancer cell lines, CL1-0 and CL1-5. hnRNP B1 is an mRNA biomarker that is overexpressed in lung cancer tissue in the early stage of cancer and can be found in the serum and plasma of lung cancer patients.
The protein alpha CP-4 (also known as hnRNP E4) is an RNA binding protein encoded by a gene at 3p21, one of the most common altered regions in lung cancer.
Using total RNA extracted from 600 mul of plasma, we detected hnRNP B1 mRNA in 39.1% (9/23) of lung cancer patients, with levels ranging from 1.9 to 19,045.5 copies/100 ng RNA, and in 5.2% (5/97) of healthy volunteers.
Our results also suggest that the expression and processing of each hnRNP protein in lung cancer is independently regulated and is not exclusively related to proliferation status.
Considering the problems involved in prevention of human lung cancer, growth inhibition of human lung cancer cell line A549 was studied with emphasis on two parameters: green tea polyphenols, such as (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG); and heterogeneous nuclear ribonucleoprotein B1 (hnRNP B1), a new biomarker of human lung cancer which is highly expressed in the very early stages of human lung cancer.
This paper briefly reviews four topics related to mechanisms of action of tea polyphenols: (I) identification of the genes commonly affected by EGCG, as demonstrated by Clontech's Atlas cDNA Expression Array; (II) the significance of heterogeneous nuclear ribonucleoprotein B1 (hnRNP B1) as a new biomarker for early detection of lung cancer, and inhibition of its expression by EGCG; (III) the synergistic or additive effects of EGCG with the cancer preventive agents, sulindac and tamoxifen, on induction of apoptosis in PC-9 cells and on inhibition of intestinal tumor development in multiple intestinal neoplasia (Min) mice; (IV) the results of a 10 year prospective cohort study demonstrating the effectiveness of daily consumption of green tea in preventing cancer, and a prototype study for developing green tea beverage as cancer preventive.