Prostate tissue specificity of the prostate-specific antigen promoter isolated from a patient with prostate cancer.

We have cloned and characterized a 620-bp fragment of DNA that flanks 5' of the prostate-specific antigen (PSA) gene from a prostate cancer patient. Using DNA transfection, the efficacy of this putative promoter in regulating gene expression was quantitated in several prostate and nonprostate tissue cell lines. Our results demonstrated that the 620-dp DNA fragment actively drives gene expression in LNCaP, a PSA-producing prostate tumor cell line. No promoter activity was detected in the non-PSA-producing prostate tumor lines, DU145 and PC-3, nor in a renal (R11) or breast (MCF-7) cancer cell line. Furthermore, the promoter activity could be regulated in vitro by androgen stimulation. Dihydrotestosterone (DHT) concentrations between 3 and 30 nM induced the highest promoter activity in the transfected LNCaP cells, which parallels the expression profile of the androgen receptor in LNCaP cells. In addition, our PSA promoter exhibited competitive inhibition of the endogenous genomic PSA promoter in transfected LNCaP cells, suggesting that prostate cell-specific DNA-binding proteins are required to activate the PSA promoter. increased its potency four- to five-fold while retaining tissue specificity. Our data suggest that a strong tissue-specific negative regulatory element capable of overriding the nonspecific CMV promoter is present in the PSA promoter and confers its tissue specificity. The use of a highly specific promoter-driven gene vector will allow selective expression of therapeutic genes within PSA-producing prostate cancer cells, providing a unique strategy for prostate cancer gene therapy.

PC12 variants deficient in norepinephrine transporter mRNA have wild type activities of several other related transporters.

Wild type PC12 pheochromocytoma cells express a Na(+)-dependent norepinephrine transporter that operates in the uptake of catecholamines. In addition to the previously described Na(+)-dependent system A for the uptake of alpha-amino-isobutyric acid and system Gly for glycine, we have identified two other Na(+)-dependent transporter systems for amino acid uptake in these cells: 1) system beta for beta-alanine and taurine; and 2) a system for creatine. Uptake of alpha-amino-isobutyric acid, glycine, beta-alanine, and creatine is not affected in some PC12 variants that were previously shown to be deficient in catecholamine uptake and to have decreased levels of norepinephrine transporter mRNA. We have isolated two PC12 cDNA clones that are essentially identical in sequence to recently reported cDNAs for rat brain taurine and creatine transporters, respectively, and a third cDNA that appears to code for a novel transporter. mRNAs for these three transporters are present at wild type levels in those variants that express no or little norepinephrine transporter mRNA. These results support the notion that the expression of catecholamine reuptake transporters may be particularly susceptible to down-regulation.

Microsurgical testis biopsy: a novel technique for retrieval of testicular tissue.

PURPOSE: In vitro fertilization with intracytoplasmic sperm injection has resulted in a dramatic increase in the need for diagnostic and therapeutic testis biopsies. We developed a microsurgical testis biopsy technique which allows identification of testicular vessels and individual seminiferous tubules. We compare the results of this technique to our prior series of nonmicroscopic biopsies. MATERIALS AND METHODS: A retrospective study of 226 consecutive patients who had undergone open testes biopsy with or without an operating microscope was performed. Between 1988 and 1994 standard open testis biopsy was performed without a microscope in 119 patients and a single sample of testicular tissue was taken. After 1994 microsurgical biopsy was performed under 6 to 25x magnification in 107 patients, nearly half of whom had multiple biopsies of each testis. The complication rates of the 2 procedures were compared. RESULTS: Scrotal hematoma required surgical drainage in 3 of the 119 standard testis biopsy cases and testis atrophy was noted in 1, for a total complication rate of 3.4%. There were no episodes of clinically detectable testicular atrophy or scrotal hematoma requiring surgical drainage in the 107 microsurgical biopsy cases (p<0.05). In 2 men the microscope allowed identification of larger tubules that contained sperm. CONCLUSIONS: Use of the operating microscope for testicular biopsy allows identification and avoidance of testicular vessels, minimizing complications. It also may allow selection of seminiferous tubules more likely to contain sperm.