The study of PSA gene expression on urogenital cell lines

Purpose: Reverse transcriptase-polymerase chain reaction (RT-PCR) offers a potentially more sensitive assay for detecting cells expressing prostate-sp ecific antigen (PSA) mRNA in peripheral circulation. But: the sensitivity a nd specificity are variable depending on the position of the PSA amplificat ion. To increase sensitivity and specificity, the whole PSA cDNA (1466 bp) was separated into eight different parts. Methods: We examined RT-PCR on 12 urogenital cell lines, including three pr ostate cancer (LNCaP, PC3, DU145), five human renal cell carcinoma (SMKT-R3 , TOS-1, TOS-2, R4, ACHN), two urinary bladder cancer (YTS-1, KK-47) and tw o testicular cancer (NEC8, NEC14) cell lines. The sizes of the eight fragme nted PSA used in the experiment were PSA-1 (1-257 bp), PSA-2 (1-322 bp), PS A-3 ( 172-507 bp), PSA-4 (172-851 bp), PSA-5 (595-1347 bp), PSA-6 (682 967 bp), PSA-7 (682-1347 bp) and PSA-8 (863-1466 bp). Results: All cell lines had positive signals from PSA-6, PSA-7 and PSA-8. T he positive signals from PSA-1, PSA-2 and PSA-3 were detected in some other cell lines in addition to the three prostate cancer cell lines. Only LNCaP which produces the PSA protein had a positive signal From PSA-5. PC3 and D U145 (which do not produce PSA) and LNCaP had a positive signal from PSA-4. Therefore, the inner primer PSA-4' (578-782 bp) used to increase sensitivi ty and specificity. Nested RT-PCR on the 12 cell lines, using the PSA-4 and 4' primers, detected more clear bands in the three prostate cancer cells. Conclusion: Nested RT-PCR: using PSA-4 (outer primer) and PSA-4' (inner pri mer) may be useful for detecting prostate cancer cells in the peripheral bl ood.