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R Buttyan

Publications and source records attributed to R Buttyan.

At least 55 records · Page 3Linked to original sources
PubMed1999

Expression of messenger ribonucleic acid splice variants for vascular endothelial growth factor in the penis of adult rats and humans.

Erectile dysfunction is often associated with problems in vascular perfusion to the erectile components of the penis. In order to better understand the factors that control vascular formation and perfusion in the erectile tissues of the penis, we have begun to characterize the expression of vascular endothelial growth factor (VEGF) in penis tissues. VEGF is one of several polypeptides that have significant angiogenic activity in vitro and in vivo. Extensive characterization of the VEGF gene and its products has shown that several different mature mRNA transcripts exist, originating from alternative splicing of the basic VEGF transcript. These variant transcripts can encode peptides with different biological activities. Penile tissue was obtained from adult rats and from human patients undergoing penile prosthesis implantation. Analysis of the forms of VEGF transcripts was performed using a reverse transcription-polymerase chain reaction technique with primer pairs derived from the first and eighth exon of the VEGF gene. The expression levels of the various isoforms in the rat penis were then quantified using RNase protection assays. Four previously described splice variants of VEGF mRNA (VEGF 120, 144, 164, 188) were detected in rat and human penile tissues. In contrast to what is seen in the rat lung, where the most abundant form of VEGF mRNA is the 188 splice isoform, VEGF 164 is the most abundant transcript detected in the penis. Finally, sequence analysis of numerous VEGF cDNA clones obtained from the rat penis demonstrated the presence of a previously undescribed VEGF splice variant that could give rise to a protein of 110 amino acid residues (VEGF 110, GenBank accession no. AF080594). In summary, a number of VEGF mRNA isoforms are expressed in the rat and human penis, with the splice variant encoding a 164-amino acid protein present in greatest abundance. This study is a prelude to attempts to genetically manipulate VEGF expression in the penis as a therapy for erectile dysfunction.

Adult↗
PubMed1999

Can perineural invasion on prostate needle biopsy predict prostate specific antigen recurrence after radical prostatectomy?

PURPOSE: We evaluated the role of perineural invasion identified on prostate needle biopsy as a predictor of prostate specific antigen (PSA) recurrence after radical prostatectomy. MATERIALS AND METHODS: Between 1993 and 1998 radical prostatectomy was performed in 319 consecutive patients. Prostate needle biopsies were reviewed in all cases. We compared perineural invasion with other preoperative parameters, including digital rectal examination, PSA and biopsy Gleason score, for the ability to predict PSA recurrence with recurrence defined as any serum PSA level greater than 0.2 ng./ml. RESULTS: Perineural invasion was identified on 77 of 319 preoperative prostate biopsies (24%). There was PSA recurrence in 46 patients (14.4%) at a mean followup of 25.4 months (range 0.2 to 62.1). Perineural invasion statistically correlated with PSA recurrence. Kaplan-Meier analysis revealed disease-free survival rates of 24 versus 64% when perineural invasion was and was not present in the prostate biopsy (p = 0.0003, log rank 12.92). Multivariate analysis demonstrated that perineural invasion (p = 0.012) and PSA (p = 0.005) were independent preoperative predictive factors of PSA recurrence. When perineural invasion was compared with postoperative parameters, including disease stage, surgical margins and seminal vesicle invasion, it was not an independent predictor because it closely correlated with tumor stage. CONCLUSIONS: Perineural invasion on preoperative prostate needle biopsy is a strong independent predictor of PSA recurrence in patients in whom prostate cancer was treated with radical prostatectomy.

Adult↗
PubMed1999

Early effects of castration on the vascular system of the rat ventral prostate gland.

Recent studies have found that blood flow to the rat ventral prostate gland is drastically reduced at an early time after castration. These observations caused us to reevaluate the effects of castration on the various cell populations of the ventral prostate, especially those in the prostatic vascular system. Sections of ventral prostate glands obtained at different times after castration were analyzed using the TUNEL (terminal deoxynucleotide transferase-mediated dUTP nick END labeling) staining method to quantify apoptosis in different cell types. The results of this analysis showed a significant increase in TUNEL staining of prostate endothelial and (nonendothelial) stromal cells as early as 12 h postcastration that continued to 24 h after castration. In contrast, TUNEL labeling of prostate epithelial cells was not significantly increased compared with control values until 72 h after castration. The use of dual immunohistochemical staining procedures (anti-CD31 for endothelial cells or antismooth muscle actin for smooth muscle cells combined with TUNEL labeling) allowed us to confirm that the TUNEL-positive vascular cells at these early times after castration were endothelial in nature, whereas smooth muscle cells surrounding the prostate glands or portions of the afferent vascular endothelium were rarely TUNEL labeled. Electron microscopic evaluation of ventral prostate tissues at 48 h after castration provided further morphological evidence for the occurrence of apoptosis in prostate endothelial cells. Finally, the Lendrum-Fraser histochemical procedure used to identify fibrin leakage in tissues with vascular damage was applied to sections of the ventral prostate gland. This stain revealed diffuse fibrin accumulation in periglandular areas outside the capillaries and blood vessels in prostates from 24-h castrated rats, but not in prostates of sham-operated rats. Our results confirm an early effect of castration on the vascular system of the rat ventral prostate identified by increased apoptosis of endothelial cells and vascular leakiness. As these changes temporally precede the loss of epithelial cells, we propose that they may be causal rather than incidental to regression of the rat ventral prostate after castration.

Actins↗
PubMed1999

[Columbia University experience of detection of circulating cells by RT-PCR PSA in prostate cancer as a predictive factor of stage and biochemical recurrence].

OBJECTIVES: The Columbia University experience of RT-PCR PSA as a predictive factor of stage and biochemical recurrence is reviewed by trying to explain its differences. PATIENTS AND METHODS: 319 patients were included between January 1993 and March 1998. Radical prostatectomy was performed in all patients by the same surgeon. The RT-PCR protocol has been previously described (Katz et al., Urology, 1994). Biochemical recurrence was defined by a PSA greater than or equal to 0.2 ng/ml. RESULTS: Histological examination diagnosed 218 pT2 and 101 pT3 tumours. Thirty-four of the 218 pT2 patients (16%) had a positive RT-PCR versus 51 of the 101 pT3 patients (51%, p < 0.001). Analysis of Kaplan-Meier curves showed an 84% recurrence-free survival when RT-PER was negative versus 47% when RT-PCR was positive (Log-rank test, p = 0.0002). Multivariate analysis showed that independent predictive factors of biochemical recurrence were stage (p = 0.004), Gleason score estimated on the operative specimen (p = 0.010) and serum PSA (p = 0.047); RT-PCR (p = 0.075), strongly correlated with stage, was not an independent predictive factor. By exclusively comparing preoperative parameters, PSA (p = 0.004) and RT-PCR (p = 0.006) were found to be independent predictive factors compared to digital rectal examination (p = 0.371) and Gleason score on biopsies (p = 0.076). CONCLUSION: In this institution, RT-PCR PSA is a predictive parameter of stage and biochemical recurrence. No consensus has yet been reached in the literature concerning the reference protocol, as each team has developed its own RT-PCR technique applied to its own patient population. Comparison of results is therefore difficult.

Adult↗
PubMed1999

Castration induces acute vasoconstriction of blood vessels in the rat prostate concomitant with a reduction of prostatic nitric oxide synthase activity.

PURPOSE: Previous studies demonstrating a rapid and drastic reduction of blood flow to the rat prostate gland resulting from castration caused us to consider the influence of castration on the state of vascular constriction and on the activity of the vascular tone-regulating factors (nitric oxide synthase and cyclic GMP) in the rat prostate. MATERIALS AND METHODS: Sections of ventral prostate glands obtained from intact and castrated rats were analyzed for the mean areas within smooth muscle-coated blood vessels using a computerized microscopic image analysis system. Nitric oxide synthase (NOS) levels were measured in prostatic extracts from unoperated or castrated rats using an enzyme assay system that measures conversion of 3H-L-arginine to citruline. Cyclic GMP levels were measured in prostatic extracts from unoperated or castrated rats using a competitive radioimmunoassay system. RESULTS: The mean area within ventral prostate smooth muscle-coated blood vessels was reduced 39% at 24 hours after castration (p = 0.039) and 47.7% at 48 hours after castration (p = 0.039). NOS activity measured in prostatic extracts was reduced 38% at 24 hours (p = 0.0012) and 51.6% at 36 hours after castration (p = 0.0001) compared with the control group of noncastrated rats. Finally, prostatic cGMP levels were reduced 55.8% (p = 0.0018) at 36 hours after castration when compared with controls rats. CONCLUSION: Within 24 hours after castration, the lumenal areas of smooth muscle-coated blood vessels in the rat prostate gland were found to be significantly reduced. This vasoconstriction was associated with a significant reduction of prostatic NOS activity as well as a reduction in the prostatic levels of the NOS co-factor, cGMP. Thus, acute vasoconstriction is a prominent early event associated with rat prostate regression in response to castration and likely contributes to the regression of the tissue.

Animals↗
PubMed1999

Transdifferentiation of prostate cancer cells to a neuroendocrine cell phenotype in vitro and in vivo.

PURPOSE: To better understand the source of neuroendocrine cells associated with human prostate cancer progression, we studied the ability of a cultured prostate cancer cell line, LNCaP, to transdifferentiate into neuroendocrine-like cells in vitro and in vivo. MATERIALS AND METHODS: Cyclic AMP concentrations were measured in extracts of LNCaP cells cultured in the presence of normal or hormone-deficient medium (containing charcoal-stripped serum) with the use of an immunoassay. Quantitative RT-PCR procedures were used to determine whether hormone depletion affects TGF-beta2 mRNA expression. Western blotting procedures (for neuron specific enolase [NSE]) were used to determine whether TGF-beta2 supplementation or antibody neutralization might affect the ability of cultured LNCaP cells to transdifferentiate to neuroendocrine-like cells. Finally, tumors formed from LNCaP cells xenografted into male nude mice were evaluated for the presence of neuroendocrine cells (prior and subsequent to castration of the host mouse) using an immunohistochemical stain for chromogranin A. RESULTS: LNCaP cells cultured in a hormone-deficient medium have a mean 9-fold increase in cyclic AMP (p = 0.02) and a significant decline in the expression of TGF-beta2 mRNA when compared with cells grown in normal medium. Supplementation or depletion of TGF-beta2 did not affect the neuroendocrine conversion of LNCaP cells as assessed by NSE expression patterns. LNCaP tumors growing in castrated male nude mice were found to have significantly increased numbers of chromogranin A positive neuroendocrine cells (46/high powered field) when compared with tumors growing in intact male mice (3/high powered field) (p = 0.0038). CONCLUSIONS: Exposure of LNCaP cells to a hormone deficient medium drastically increased cyclic AMP production and this may identify the biochemical pathway through which hormone depletion induces a neuroendocrine conversion of prostate cancer cells. Hormone depletion also reduced TGF-beta2 mRNA expression and this finding was consistent with our inability to demonstrate any effect of TGF-beta2 on neuroendocrine conversion in vitro. Finally, our demonstration of increased neuroendocrine cells found in LNCaP tumors growing in castrated immunodeficient mice suggests that the neuroendocrine cells associated with advanced human prostate tumors in vivo, arise from prostate cancer cells through the transdifferentiation process.

Animals↗
PubMed1998

Rapid reduction in blood flow to the rat ventral prostate gland after castration: preliminary evidence that androgens influence prostate size by regulating blood flow to the prostate gland and prostatic endothelial cell survival.

BACKGROUND: Androgenic steroids regulate the development and size of the mammalian prostate gland. The mechanism(s) for this growth control might involve a direct effect on prostate cell proliferation and survival as well as more complex effects on the tissue environment supporting nourishment and oxygenation. In this study, we evaluated an animal model of androgen action on the prostate, the rat ventral prostate gland, to determine whether acute androgen withdrawal, by means of castration, might alter the primary blood flow to the prostate gland and for the effects of castration on prostatic endothelial cell viability. METHODS: Groups of rats studied included intact control males, males that had been surgically castrated, or males that received a sham-surgical castration. Relative blood flow (RBF) to the rat ventral prostate glands and rat bladders were measured at 18 and 24 hr after castration or sham castration using a fluorescent microsphere infusion technique. Thin sections from fixed and embedded rat ventral prostate glands obtained from unoperated or 12-hr castrated rats were analyzed by the TUNEL immunostaining technique to microscopically identify and quantify apoptotic epithelial, stromal, and endothelial cells. RESULTS: RBF to the rat ventral prostate was reduced by 38%, at 18 hr after castration when compared with intact or sham-operated rats and by 45% at 24 hr after castration (P=0.038 unoperated/0.025 sham operated). In contrast, RBF to the bladder was not significantly different between any of the groups in the 24-hr castrate experiment. TUNEL staining analysis of ventral prostate tissues obtained from 12-hr castrated rats showed only rare TUNEL-positive epithelial cells similar to the control tissue but significantly increased TUNEL labeling for endothelial and other ventral prostate stromal cells. CONCLUSIONS: Castration resulted in a rapid and significant reduction of blood flow to the mature rat ventral prostate gland that was not seen in the bladder. This reduction precedes the appearance of apoptosis in the epithelial cells of the tissue but more coincided with the appearance of TUNEL-positive prostate vascular endothelial and stromal cells, suggesting that androgens support the survival of cells in the vascular and stromal compartment of the rat prostate as well as in the prostatic epithelium. These preliminary data support the concept that androgen action on the prostate might involve primary regulation of prostate blood flow and prostate vascular cell vitality.

Androgens↗
PubMed1998

Androgen induction of DNA synthesis in the rat penis.

OBJECTIVES: The androgen sensitivity of the mammalian penis has long been appreciated. However, the precise biochemical and structural sequelae of alterations in testosterone, and the mechanisms thereof, remain to be elucidated. Recently, the androgen dependence of rat penile erectile tissue was further clarified at our institution, where the induction of apoptosis was demonstrated in response to castration. In continuity, we report the results of a follow-up study of the regenerative capacity of the regressed, castrated rat penile erectile tissue when testosterone is replenished. METHODS: Three groups of rats were used: normal control rats, castrated without testosterone replenishment, and castrated with subsequent testosterone replenishment. In the third group, castrated rats were given testosterone and killed at 24-hour intervals over 4 days. Specimens of the penis, small bowel, and prostate were obtained from all animal groups. Immunohistochemical identification of intraperitoneally administered 5-bromo-2'-deoxyuridine, a thymidine analogue, was performed to detect new DNA synthesis. The incorporation of this molecule into high molecular weight nuclear DNA served as a measure of DNA synthesis and, hence, cellular proliferation. RESULTS: Testosterone-replenished castrated rat penile stromal cells, both cavernosal and spongiosal, showed more enhanced proliferative activity than those of both castrated unreplenished and uncastrated control rats. Trichrome staining permitted the differentiation of responsive cell subsets. Various cell types were found to respond to replenished testosterone, including myocytes, fibrocytes, endothelial cells, and Schwann cells. Pronounced DNA synthesis occurred as early as 48 hours after the replenishment of testosterone. For purposes of technique validation, sections of small bowel were examined, in which glandular crypt cells would be expected to show rapid turnover. The nuclei of these bowel sections stained in all animal groups throughout the experiment, thus validating the staining technique. The technique of castration and testosterone replenishment was validated by confirming the known response of rat ventral prostate to androgen withdrawal and replenishment. CONCLUSIONS: Our findings provide evidence that testosterone induces cellular proliferation and new DNA synthesis in the penile erectile tissue of castrated rats. This response to testosterone is not limited to one cell type, but rather is multicellular.

Animals↗
PubMed1998

Zonal variation of apoptosis and proliferation in the normal prostate and in benign prostatic hyperplasia.

OBJECTIVE: To determine whether benign prostatic hyperplasia (BPH) results from an imbalance between cell proliferation and apoptosis, and the extent to which the rates of these opposing processes are altered with the expression of the anti-death oncoprotein bcl-2. MATERIALS AND METHODS: Ten prostate glands from normal men (mean age 43.7 years) were sampled according to McNeal's zonal anatomy, in addition to 30 prostate adenomas obtained from prostatectomy specimens from symptomatic patients (mean age 61.4 years). Tissue samples were fixed in formalin and embedded in paraffin. Proliferation and bcl-2 expression were assessed by immunostaining using Mib-1 and anti-bcl-2 antibodies, while apoptotic bodies were specifically stained using in situ nick translation. The percentage of positive cells was determined by optical microscopy. RESULTS: In normal epithelium, the rates of proliferation and apoptosis were increased in the peripheral zone (Mib-1 1.7%, apoptotic bodies 3.3%) compared with the central (0.2% vs 1.4%) and transition (0.1% vs 1.8%) zones. Proliferation was significantly greater in BPH than in normal prostate tissue (3.7%), contrasting with a stable rate of apoptosis (1.4%). In the normal prostate, bcl-2 was expressed by glandular and basal cells in the peripheral zone. In the central zone, bcl-2 was overexpressed in basal cells and in most glandular cells of the intraluminal ridges. Bcl-2 expression in the transition zone was limited to dispersed basal cells. In BPH, bcl-2 was strongly expressed by basal cells in mature glandular formations and in most cells of young small nodules. CONCLUSION: BPH may result from both an increase of proliferation within the basal compartment and a failure of apoptosis to counterbalance basal cell proliferation. Increased expression of bcl-2 may participate in this process by blocking apoptosis.

Adult↗
PubMed1998

The role of tumor biomarkers as predictors of serum PSA recurrence after radical prostatectomy.

Tumor biomarkers (p53, bcl-2, Ki-67, and RT-PCR) were reviewed in the literature for their ability to predict prostate-specific antigen (PSA) biological recurrence after radical prostatectomy. All of them are strongly associated with PSA recurrence on univariate analysis. p53 seems to be better than current predictors, such as stage, grade, and positive surgical margins on multivariable analysis; further studies need to confirm bcl-2 and Ki-67 as better predictors of PSA recurrence. However, most of these studies were performed on radical prostatectomy specimens and will need to be confirmed on the preoperative prostate biopsy. The RT-PCR assay was strongly correlated with PSA recurrence and was one of the two best preoperative PSA recurrence predictors with serum PSA.

Biomarkers, Tumor↗
PubMed1997

Development of a hammerhead ribozyme against bcl-2. I. Preliminary evaluation of a potential gene therapeutic agent for hormone-refractory human prostate cancer.

BACKGROUND: The bcl-2 oncoprotein suppresses apoptosis and, when overexpressed in prostate cancer cells, makes these cells resistant to a variety of therapeutic agents, including hormonal ablation. Therefore, bcl-2 provides a strategic target for the development of gene knockout therapies to treat human prostate cancers. Towards this end, we have synthesized an anti-bcl-2 gene therapeutic reagent based on ribozyme technology and have tested its effectiveness against bcl-2 mRNA in vitro and in vivo. METHODS: A divalent hammerhead ribozyme was constructed by recombining two catalytic RNA domains into an antisense segment of the coding region for human bcl-2 mRNA. A disabled ribozyme lacking catalytic activity was also constructed as a control reagent for our experiments. The ribozymes were tested for endonucleolytic activity against synthetic and natural bcl-2 mRNAs. Simple transfection procedures were then utilized to introduce the ribozymes into cultured prostate cancer cells (LNCaP derivatives). We measured the effects of the ribozymes on endogenous expression of bcl-2 mRNA and protein in these cells as well as their ability to induce apoptosis. RESULTS: The functional but not the disabled ribozyme was able to rapidly degrade bcl-2 mRNA in vitro, without the requirement for any other cellular protein or factor. When directly transfected into LNCaP cell variants, it significantly reduced bcl-2 mRNA and protein levels within 18 hr of treatment. This activity was sufficient to induce apoptosis in a low-bcl-2-expressing variant of LNCaP, but not in a high-bcl-2-expressing LNCaP line. For the high-bcl-2-expressing variant, however, it did restore the ability to genetically respond to a secondary apoptotic agent, phorbol ester, as evidenced by the renewed ability of phorbol ester to induce NGF1A mRNA in these cells. CONCLUSIONS: This study supports the potential utility of an anti-bcl-2 ribozyme reagent for reducing or eliminating bcl-2 expression from hormone-refractory prostate cancer cells and for killing prostate cancer cells. As such, it is the first step toward an effective gene therapy against hormone-refractory human prostate cancers.

Base Sequence↗
PubMed1997

Abnormal prostate development in C3(1)-bcl-2 transgenic mice.

BACKGROUND: Recent hypotheses to explain the etiology of abnormal growth associated with prostate disease have invoked perturbations in the rate of apoptosis as an important contributor to the onset and progression of these diseases. For this reason, the apoptosis suppressing oncoprotein bcl-2 has come under scrutiny with regards to its role in prostate diseases. In order to evaluate the role of bcl-2 in human prostate disease and to develop an animal model to test anti-bcl-2 therapies, we generated transgenic mice in which bcl-2 expression is targeted to the mouse prostate gland. METHODS: Mouse embryos were microinjected with recombinant DNA constructed by fusing a modified rat C3(1) promotor element to cDNA encoding human bcl-2. Presence of the C3(1)-bcl-2 transgene in progeny was identified by Southern blot and polymerase chain reaction (PCR) analysis. RNase protection assays were used to analyze RNA from 15 organs of these mice. Western blot assays and immunohistochemical staining were used to confirm the tissue-specific protein expression of human bcl-2 and its cellular localization. RESULTS: Three lines of C3(1)-bcl-2 transgenic mice were established. Founder mice carried 2-20 copies of the transgene. Expression of human bcl-2 from the transgene was limited to the prostate gland and testis of males as well as the uterus of females. In the prostate gland, human bcl-2 protein was found only in prostatic epithelial cells. Microscopic analysis of prostate glands from individual males (three lines) showed that these glands were often abnormal, with increased accumulation of cells in the prostatic stroma as well as the epithelium. CONCLUSIONS: These transgenic mice appear to provide a novel animal model for studying neoplastic development of the prostate, with particular emphasis on the bcl-2 protein and the role of apoptosis regulation in such development.

Animals↗
PubMed1997

Detection of circulating prostate carcinoma cells via an enhanced reverse transcriptase-polymerase chain reaction assay in patients with early stage prostate carcinoma. Independence from other pretreatment characteristics.

BACKGROUND: Circulating prostate cells can be detected in the venous blood of patients with clinically localized prostate carcinoma by applying reverse transcriptase-polymerase chain reaction (RT-PCR) techniques using primers specific for the prostate specific antigen (PSA) gene. This study evaluates whether the detection of circulating cells correlates with established prognostic factors, treatment, and pathologic stage. METHODS: Two hundred and twenty-seven patients with clinically localized adenocarcinoma of the prostate had an RT-PCR assay performed as part of their staging evaluation. No treatment decisions were made on the basis of the RT-PCR results. Of these, 156 patients were treated with radical prostatectomy (RP) and 71 with radical external beam radiotherapy (EBRT). Forty-eight patients were treated with hormonal therapy prior to RP (n = 39) or EBRT (n = 9). The prognostic factors analyzed for their relationship to RT-PCR were clinical stage, pretreatment serum PSA levels, Gleason score of the biopsy specimen, and Gleason score of the surgical specimen. An analysis of the relationship between treatment and RT-PCR results was also performed. Multivariate logistic regression analysis of predictors of RT-PCR positivity was performed as well. In addition, univariate and multivariate analyses of predictors of pathologic stage, including RT-PCR, were performed. RESULTS: Sixty-one patients (26.9%) had a positive RT-PCR assay. There was no relationship between clinical stage, pretreatment PSA, biopsy Gleason score, or surgical Gleason score and RT-PCR positivity. In univariate analysis, patients treated with RP had a higher rate of RT-PCR positivity than patients treated with EBRT (P = 0.054). However, in multivariate logistic regression analysis no factor, including treatment with RP, was a significant predictor of RT-PCR positivity. RT-PCR and pretreatment PSA predicted pathologic stage in univariate and multivariate analyses (P < 0.0001 and P = 0.002, respectively). CONCLUSIONS: The detection of circulating prostate cells using RT-PCR occurs in approximately 25% of early stage prostate carcinoma patients and is independent of other established prognostic factors. In addition, a positive RT-PCR assay is a strong predictor of pathologic upstaging in patients with clinically organ-confined disease.

Analysis of Variance↗
PubMed1997

Expression of the tumor-associated gene MN: a potential biomarker for human renal cell carcinoma.

MN is a novel cell surface antigen originally detected in human HeLa cells. Although it is also expressed in normal gastric mucosa, this antigen was previously found to be expressed in cells with a malignant phenotype in certain tissues of the female genital tract (cervix and ovary). Using an oligonucleotide primer set specific for MN-complimentary DNA, we performed reverse transcription-PCR assays on RNAs extracted from human cell lines and tissues to evaluate whether this marker might be expressed at other sites. RNA libraries extracted from normal human heart, lung, kidney, prostate, peripheral blood, brain, placenta, and muscle were negative for MN expression. RNAs extracted from liver and pancreatic tissue were positive for MN expression. Three of six renal cancer cell lines tested revealed MN expression. In addition, 12 of 17 samples of human renal cell carcinoma tissue tested positive for MN, all 12 of which were clear cell adenocarcinomas. This survey identified a unique association of MN expression with renal cell cancers, especially those of the clear cell variety, suggesting that MN is a potential marker for the diagnosis, staging, and therapeutic monitoring of renal cell carcinoma in humans.

Antigens, Neoplasm↗
PubMed1997

Epidermal growth factor suppresses renal tubular apoptosis following ureteral obstruction.

OBJECTIVES: Acute unilateral ureteral obstruction (UUO) results in ipsilateral hydronephrosis characterized by a decrease in epidermal growth factor (EGF) mRNA expression and EGF protein levels in the distal renal tubules. UUO results in programmed cell death with increases in the characteristic markers of apoptosis. To suppress the apoptotic response during UUO, recombinant EGF was administered during renal obstruction and the ensuing molecular and histologic changes were studied. METHODS: Mature Sprague-Dawley rats underwent left ureteral obstruction and the kidneys were harvested at 24, 48, and 72 hours. Markers of apoptosis included DNA laddering pattern on agarose gel electrophoresis, in situ gap labeling of fragmented DNA for quantitative apoptotic body determination, polyadenylated mRNA expression of SGP-2, and in situ hybridization for sulfated glycoprotein-2 (SGP-2) mRNA. Studies were repeated in rats following administration of 10, 20, and 40 micrograms of subcutaneous recombinant EGF on a daily basis after UUO. RESULTS: Subcutaneous injection of EGF into unilaterally obstructed rats promotes renal tubular epithelial cell regeneration, as demonstrated by increased cortical mitotic activity. Systemic EGF supplementation in these unilaterally obstructed rats also resulted in a decrease in the intensity of the DNA laddering pattern associated with renal tubular apoptosis. An in situ labeling procedure to identify apoptotic nuclei in the ureterally obstructed kidneys revealed a 50% reduction in apoptosis after EGF administration. Northern blot analysis and in situ hybridization for SGP-2 mRNA or clustering gene product also revealed a decreased expression in the obstructed and EGF-treated renal parenchyma. CONCLUSIONS: These data suggest that EGF, apart from its known role as a mitogenic substance for renal tubular epithelial cells, is also a critical in vivo renal cell survival factor for the developmentally mature kidney.

Animals↗
PubMed1997

Reverse transcriptase-polymerase chain reaction assays for prostate cancer.

RT-PCR, if targeted against a prostate-specific marker, can be a highly specific and sensitive assay to detect the presence of occult prostate cancer cells at sites far distant from the primary tumor. The low false-positive rate (0.8%) observed when combining most published studies and the high rate of detection of prostate cells in metastatic patients (88%) found in well-defined clinical studies address the basic requirements of a clinically effective diagnostic modality. Additionally, all reports indicate that RT-PCR positivity for PSA or PSMA increases with increased stage of prostate cancer, suggesting that RT-PCR assays may have value in staging the patient presumed to have clinically localized disease. Indeed, data from two institutions have shown the unique contribution that RT-PCR technology might lend to this most vexing problem. With the suggestive data already published, we remain optimistic that molecular staging will become a reality in the future. After all, the variability in techniques of RT-PCR (as well as differences in targets and samples assayed) used by the various laboratories now investigating this method could themselves be responsible for many of the differences reported. There is no question that standardization among laboratories is essential before clinical utility of molecular staging can be proved. Indeed, this endeavor represents the major aim of the RT-PCR consortium in the United States. Nevertheless, at our own medical center, we are struck by our finding that if a preoperative RT-PCR for PSA is negative, the patient can be assured of a successful operative outcome in 88% of cases. We also are impressed by the data showing that if the serum PSA level is greater than 10 ng/mL and the RT-PCR assay is positive, 90% of patients undergoing radical surgery have adverse pathology reports (and, in fact, have already experience operative failure in nearly half the cases). There is increasing consensus that RT-PCR assays afford prognostic information that is also unique. Three institutions have similar data comparing operative or preoperative RT-PCR strategies (employing all three potential sample sources) with treatment outcome. This may suggest the validity of RT-PCR as a staging modality or, alternatively, suggest that a truly metastatic phenotype is identified in patients with circulating PSA-synthesizing cells, or in patients harboring PSA-synthesizing cells in node or marrow tissues. In either case, RT-PCR appears already to provide information not available before the use of this technology. In fact, in the only series comparing RT-PCR with other, more established predictors (PSA, Gleason score) in a multivariate analysis, RT-PCR status provided the best prognostic information. Prostate manipulation does, in fact, appear to affect the RT-PCR assay. Although digital rectal examination and cystoscopy do not seem sufficiently invasive to release prostate cells into the circulation, a small number of individuals undergoing transrectal ultrasound biopsy will experience this phenomenon. This observation provides a cautionary note relative to timing of sample collection for RT-PCR assays. Furthermore, a significant fraction of patients undergoing prostate manipulation during radical surgery may experience shedding of prostate cells into the operative field and release of some into the peripheral circulation. This has not been universally observed and, even if true, may not share the significance of spontaneous RT-PCR positivity (before prostatic manipulation). In the one instance, a potentially metastatic phenotype is responsible for RT-PCR positivity, whereas in the other instance, PSA or PSMA synthesizing cells may have no metastatic potential at all. Further studies on the biologic half-life of such cells are required before any clinical judgement can be made regarding this phenomenon. In summary, there appears to be consensus that RT-PCR technology can differentiate controls from patients with metas

Humans↗