Differentially expressed genes in two LNCaP prostate cancer cell lines reflecting changes during prostate cancer progression

Prostate cancer tends to become transformed to androgen-independent disease over time when treated by androgen-deprivation therapy. We used two varian ts of the human prostate cancer cell line LNCaP to study gene expression di fferences during prostate cancer progression to androgen-independent diseas e. Production of prostate-specific antigen was regarded as a marker of andr ogen-dependence and loss of prostate-specific antigen was regarded as a mar ker of androgen-independence. mRNA from both cell lines was used for cDNA m icroarray screening. Differential expression of several genes was confirmed by Northern blotting. Monoamine oxidase A, an Expressed Sequence Tag (EST) similar to rat P044, and EST AA412049 were highly overexpressed in androge n-dependent LNCaP cells. Tissue-type plasminogen activator, interferon-indu cible protein p78 (MxB), an EST similar to galectin-1, follistatin, fatty a cid-binding protein 5, EST AA609749, annexin I, the interferon-inducible ge ne 1-8U, and phospholipase D1 were highly overexpressed in androgen-indepen dent LNCaP cells. All studied genes had low or no expression in PC-3 cells. The EST similar to rat P044, the EST similar to galectin-1, follistatin, a nnexin I, and the interferon-inducible gene 1-8U were also expressed in ben ign prostatic hyperplasia tissue. The Y-linked ribosomal protein S4, Mat-8, and EST AA307912 were highly expressed in benign prostatic hyperplasia tis sue. Additionally, both confirmation of differential expression in Northern blots and in situ hybridization were carried out for monoamine oxidase A, the EST similar to rat P044, the EST similar to galectin-1, fatty acid-bind ing protein 5, and the interferon-inducible gene 1-8U. We identified severa l potential prostate cancer markers, indicating that the method used is a u seful tool for the screening of cancer markers, but other methods, such as in situ hybridization, are needed to further investigate the observations.