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Biomedical subjects

M A Rubin

Publications and source records attributed to M A Rubin.

At least 19 recordsLinked to original sources

Truncation of the beta-catenin binding domain of E-cadherin precedes epithelial apoptosis during prostate and mammary involution.

A potential target of hormone action during prostate and mammary involution is the intercellular junction of adjacent secretory epithelium. This is supported by the long-standing observation that one of the first visible stages of prostate and mammary involution is the disruption of interepithelial adhesion prior to the onset of apoptosis. In a previous study addressing this aspect of involution, we acquired compelling evidence indicating that the disruption of E-cadherin-dependent adhesion initiates apoptotic programs during prostate and mammary involution. In cultured prostate and mammary epithelial cells, inhibition of E-cadherin-dependent aggregation resulted in cell death following apoptotic stimuli. Loss of cell-cell adhesion in the nonaggregated population appeared to result from the rapid truncation within the cytosolic domain of the mature, 120-kDa species of E-cadherin (E-cad(120)). Immunoprecipitations from cell culture and involuting mammary gland demonstrated that this truncation removed the beta-catenin binding domain from the cytoplasmic tail of E-cadherin, resulting in a non-beta-catenin binding, membrane-bound 97-kDa species (E-cad(97)) and a free cytoplasmic 35-kDa form (E-cad(35)) that is bound to beta-catenin. Examination of E-cadherin expression and cellular distribution during prostate and mammary involution revealed a dramatic reduction in junctional membrane staining that correlated with a similar reduction in E-cad(120) and accumulation of E-cad(97) and E-cad(35). The observation that E-cadherin was truncated during involution suggested that hormone depletion activated the same apoptotic pathway in vivo as observed in vitro. Based on these findings, we hypothesize that truncation of E-cadherin results in the loss of beta-catenin binding and cellular dissociation that may signal epithelial apoptosis during prostate and mammary involution. Thus, E-cadherin may be central to homeostatic regulation in these tissues by coordinating adhesion-dependent survival and dissociation-induced apoptosis.

Apoptosis↗

Bladder neck-sparing modification of radical prostatectomy adversely affects surgical margins in pathologic T3a prostate cancer.

OBJECTIVES: To determine whether the bladder neck-sparing (BNS) modification of radical retropubic prostatectomy (RRP) alters the likelihood of positive surgical margins and postsurgical prostate cancer recurrence. METHODS: Surgical outcomes, as measured by pathologic margin status and progression-free survival, were evaluated in 751 consecutive RRP cases, among whom 222 underwent BNS technique. To reduce selection bias, comparison of positive margin rates between BNS and standard RRP was stratified by pathologic stage. Differences in surgical margin rates were assessed using the chi-square test, and effects of bladder neck preservation on prostate-specific antigen (PSA)-free survival were assessed, using multivariable Cox proportional hazards analysis. RESULTS: The clinical stage, Gleason score, and preoperative serum PSA profiles were similarly distributed between patients undergoing standard RRP and those undergoing the BNS modification. Surgical margins in the unstratified entire cohort were positive at rates similar to prior reports (28% BNS, 27% standard RRP). However, stratification by pathologic stage revealed that among pT3a cancers, BNS surgery was associated with significantly higher rates of positive surgical margins than was standard RRP (47% versus 20%; chi- square = 6.32, P = 0.01). Differences in positive margin rates were not seen between the two groups at other pathologic stages. The adverse effect of BNS technique on pT3a surgical margins was associated with a trend toward an adverse effect on PSA-free survival (Cox proportional hazards P = 0.016). CONCLUSIONS: The BNS modification of RRP can be associated with an increased rate of positive surgical margins specifically in cancers that have focally penetrated through the prostatic capsule (pT3a), with an associated trend toward decreased PSA-free survival in this group. BNS surgery may, therefore, compromise the ability to completely remove a subset of cancers focally penetrating the prostatic capsule.

Aged↗

10q23.3 loss of heterozygosity is higher in lymph node-positive (pT2-3,N+) versus lymph node-negative (pT2-3,N0) prostate cancer.

Loss of heterozygosity (LOH) in the region of 10q23.3 has been associated with multiple tumors, including glioblastoma multiforme, melanoma, endometrial carcinoma, and prostate carcinoma. The tumor suppressor gene, PTEN/MMAC1, is also located in this region, and, in addition to other tumor types (eg, glioblastoma multiforme, endometrial, and melanoma), PTEN/MMAC1 mutations have been found in prostate cancer cell lines, xenografts, and hormone refractory prostate cancer tissue specimens. The aim of this study was to evaluate LOH at 10q23.3 as a marker of cancer progression in node-positive prostate cancer. Genetic alterations in the region of 10q23.3 were assessed in 23 node-positive (pT2-3, N+) and 44 node-negative prostate (pT2-3, N0) cancers with D10S532, D10S1687, D10S541, and D10S583 flanking polymorphic genetic markers; PTENCA, a genetic marker within PTEN/MMAC1, was also tested. Using DNA from paired normal and microdissected tumor samples, LOH at microsatellite loci was determined after polymerase chain reaction amplification. LOH in at least 1 marker was identified in 14% (6 of 44) of lymph node-negative and 43% (10 of 23) of lymph node-positive prostate cancers (chi-square test, P = .007). This increase in genetic alterations in node-positive prostate cancer suggests that 10q23.3 is a marker for metastatic progression.

Adenocarcinoma↗

Neuroendocrine expression in metastatic prostate cancer: evaluation of high throughput tissue microarrays to detect heterogeneous protein expression.

The theory that poorly differentiated prostate carcinoma develops a neuroendocrine (NE) phenotype is controversial. Supportive data is variable with NE expression being observed in anywhere from 5% to 83% of prostate cancers. These percentages are derived from standard immunohistochemistry studies, which make no attempt to quantify the results. High-density tissue microarrays (TMAs), represent a novel method for evaluating up to 1000 tissue samples with a 0.6 mm diameter on a single glass slide. This high throughput technology for screening antibodies, however, requires validation to determine if TMAs are useful in evaluating heterogeneously expressed proteins such as the NE markers chromogranin A (CGA) and synaptophysin (SYN). This study compares results from standard slides to TMAs in 50 primary and metastatic prostate tumors taken from 12 rapid autopsies from men with hormone refractory prostate cancer. One hundred standard and 2 TMA slides were immunostained for CGA and SYN. Using standard slides, focal NE expression was seen in 1/12 primary prostate tumors. Overall, 13/100 (13%) standard slides showed focal NE expression for both primary and metastatic prostate tumors; NE expression was observed in 4/12 autopsy cases (33%) when all tumor sites per case were considered. 458 tissue elements (tumor and normal) were arrayed into one paraffin block. Seventy-three percent (332/458) of the elements placed into the TMA were confirmed histologically to represent tumor. Seventy-five percent (250/332) and 66% (218/332) could be evaluated for CGA and SYN expression, respectively. Six of the metastatic tumors expressed CGA and SYN or 2.4% (6/250; 95% CI = 0.9% to 5.2%) and 2.3% (6/218; 95% CI = 0.8% to 5.3%), respectively. In conclusion, only focal NE expression was observed by both methods (eg, standard and TMA slides). The focal expression in these advanced prostate tumors was unexpected given data from prostate tumor cell lines and animal models suggesting that progression to the NE phenotype parallels tumor progression. This study also supports the use of high density TMAs to screen for protein expression, even when expression is focal.

Adenocarcinoma↗

Relationship and significance of greatest percentage of tumor and perineural invasion on needle biopsy in prostatic adenocarcinoma.

Serum prostate-specific antigen (PSA) levels and the biopsy Gleason sum are used along with clinical staging to predict prostatectomy pathology results for men with localized prostate cancer. The additional predictive value of perineural invasion (PNI) in pretreatment prostate needle biopsies for evaluating tumor stage in this setting is controversial. The current study evaluates the independent predictive value of PNI for tumor staging in a cohort of 632 men who underwent radical retropubic prostatectomies for clinically localized adenocarcinoma of the prostate between the years 1994 and 1998. None of these men received hormonal or radiation therapy before surgery. In addition to the Gleason sum, biopsy results contained detailed information regarding tumor burden: 1) total number of biopsy cores involved by adenocarcinoma, 2) greatest percentage of any single biopsy involved by prostate carcinoma (GPC), and 3) total percentage of cancer added over all cores (TPC). The presence or absence of any PNI was recorded. Pretreatment factors were analyzed in a univariate and multivariate fashion to determine their predictive value using the TNM tumor stage (pT2 vs pT3) and the modified tumor staging system, which includes surgical margin status (pT2 vs pT3 or positive surgical margin) as end points. Univariate analysis revealed a significant association between pT3 disease and several preoperative factors including age, Gleason sum, serum PSA, digital rectal examination, PNI, GPC, TPC, and the total number of positive cores (p <0.01). Multivariate analysis indicated that serum PSA, Gleason sum, age, and GPC contributed significantly to predicting pT3 disease with odds ratios of 2.7 (95% CI, 1.7-4.3), 2.3 (95% CI, 1.7-3.1), 1.7 (95% CI, 1.1-2.7), and 1.7 (95% CI, 1.4-2.1) respectively. PNI was significant in multivariate analysis only when GPC and TPC were not considered, due to a significant interaction between GPC and PNI (p <0.0001, Wilcoxon's rank sum test). These predictive factors showed a similar relationship to adverse pathology when an alternative definition of adverse pathology was used that included positive surgical margins (pT3 or any positive margin). In the interaction between GPC and PNI, GPC was more significant than PNI in predicting pT3 disease. However, PNI added additional information when adverse pathology was defined more broadly as pT3 or any positive margin.

Adenocarcinoma↗

Intrahippocampal spermidine administration improves inhibitory avoidance performance in rats.

Polyamines are polycations present at high concentrations in the mammalian brain. We investigated the effect of an intrahippocampal infusion of spermidine, a polyamine agonist, immediately post-training on the inhibitory avoidance learning paradigm in rats. Bilateral intrahippocampal microinjection of spermidine (0.02-20 nmol) caused an increase in test step-down latencies at low concentrations. Administration of arcaine (0.002-0.2 nmol), an antagonist of the N-methyl-D-aspartate (NMDA) receptor polyamine binding site, did not modify the test step-down latencies. In contrast, co-administration of arcaine and spermidine completely reversed the facilitatory effect of spermidine on the test step-down latencies. These results provide evidence that polyamines may be involved in learning and memory modulation.

Animals↗

Is microvascular invasion on radical prostatectomy specimens a useful predictor of PSA recurrence for prostate cancer patients?

OBJECTIVE: Angiogenesis is believed to play an important role in tumor progression and metastasis. The goal of this study was to investigate the clinical utility of vascular invasion in prostate cancer patients treated by radical prostatectomy as a predictor of PSA recurrence. METHODS: Between 1993 and 1998, 241 patients underwent radical prostatectomy at our institution and had routine analysis of vascular and/or lymphatic invasion (V/LI). V/LI was correlated with preoperative parameters including digital rectal examination (DRE), Gleason score (GS) on biopsy and serum PSA, with the pathological findings and with biochemical recurrence. RESULTS: V/LI incidence was 12.4% (30 of 241 patients). Of the 30 patients with V/LI, 28 (93%) had GS > or =7 (67%) had a pT3 disease and 7 had SV invasion (23%). V/LI was not associated with DRE and GS on prostate needle biopsy. However, V/LI was correlated with the worst pathological findings including pT3 disease, seminal invasion, positive surgical margins and GS on prostate specimen > or = 7. Biochemical recurrence-free survival was 92.5% for the patients without V/LI as compared to 30.1% for patients with V/LI on prostate specimen examination (p = 0.0001). Multivariate analysis showed that preoperative serum PSA, Stage and V/LI were independent predictors of PSA recurrence. Patients with pT2 disease without V/LI had a biochemical recurrence-free survival of 99 vs. 31% in patients with V/LI (p = 0.0001). CONCLUSION: This study demonstrated that V/LI is strongly associated with biochemical recurrence after radical prostatectomy. The routine analysis of V/LI should be considered as a routine evaluation of the radical prostatectomy specimen.

Adult↗

Microvessel density as a predictor of PSA recurrence after radical prostatectomy. A comparison of CD34 and CD31.

Whether prostate cancer recurrence can be predicted by microvessel density (MVD) measurements is controversial. One reason for the lack of agreement may be the differing antibodies used to determine MVD. We evaluated MVD using 2 different antibodies against endothelial cells, CD31 and CD34, on 102 patients who underwent radical prostatectomy without adjuvant hormonal therapy. The tumors from these cases were identified, and areas with the highest Gleason pattern were immunostained. Average MVD determined by CD31 (MVD/CD31) staining was significantly lower than that obtained by MVD/CD34 staining (60.1 vs 80.3). By using Kaplan-Meier analysis, prostate-specific antigen (PSA) recurrence was correlated with MVD/CD31 and MVD/CD34. MVD/CD34 and MVD/CD31 were associated strongly with PSA recurrence on a univariate level. However, only MVD/CD34 was an independent predictor of PSA failure. Therefore, some of the confusion about MVD value as a prognostic indicator may be due to the antibodies used.

Adenocarcinoma↗

Coordinate expression of cytokeratins 7 and 20 in prostate adenocarcinoma and bladder urothelial carcinoma.

We studied the expression of cytokeratin (CK)-7 and CK-20 in prostate adenocarcinoma and urothelial carcinoma and evaluated their usefulness for distinguishing high-grade forms of these tumors. We examined prostate adenocarcinoma in 59 radical prostatectomy specimens and in 10 autopsy specimens showing metastatic disease, and urothelial carcinoma of the bladder in 28 cystectomy specimens. Immunohistochemical staining for CK-7, CK-20, and prostate-specific antigen (PSA) was performed on paraffin sections. For prostate adenocarcinoma, 5 cases had only CK-7 positivity, 5 had only CK-20 focal positivity, 1 stained for both markers, and 48 were negative for both. PSA was positive in all but 1 poorly differentiated prostatic carcinoma. In the autopsy cases, PSA was expressed in the prostate and the metastatic tumors in most cases; few cases were focally positive for CK-7 or CK-20, but none was positive for both markers. For the urothelial tumors, CK-7 was the sole positive marker in 6 cases, and CK-20 in 1 case; 17 cases were positive for both, and 4 were negative for both. All urothelial carcinomas were PSA negative. Although PSA is useful for differentiating prostatic from urothelial carcinoma, CK-7 and CK-20 are helpful when both are positive, supporting the diagnosis of urothelial carcinoma. However, if only 1 marker is positive or both are negative, these markers have limited usefulness for distinguishing these carcinomas.

Adenocarcinoma↗

Anxiolytic-like effects of 4-phenyl-2-trichloromethyl-3H-1, 5-benzodiazepine hydrogen sulfate in mice.

The pharmacological effects of 4-phenyl-2-trichloromethyl-3H-1, 5-benzodiazepine hydrogen sulfate (PTMB), a novel synthetic benzodiazepine, were examined in mice. In the elevated plus-maze test of anxiety, 0.3-1 mg/kg diazepam ip (F(3,53) = 3.78; P<0.05) and 1-10 mg/kg PTMB ip increased (F(5,98) = 3.26; P<0.01), whereas 2 mg/kg picrotoxin ip decreased (F(3,59) = 8.32; P<0.001) the proportion of time spent in the open arms, consistent with an anxiolytic action of both benzodiazepines, and an anxiogenic role for picrotoxin. In the holeboard, 1.0 mg/kg diazepam ip increased (F(3,54) = 2.78; P<0.05) and 2 mg/kg picrotoxin ip decreased (F(3, 59) = 4.69; P<0.01) locomotor activity. Rotarod assessment revealed that 1 mg/kg diazepam ip and 3, 10 and 30 mg/kg PTMB ip produced significant motor incoordination compared to vehicle control (F(4, 70) = 7.6; P<0.001). These data suggest that the recently synthesized PTMB compound possesses anxiolytic activity and produces motor incoordination similar to those observed with diazepam.

Analysis of Variance↗

Rapid ("warm") autopsy study for procurement of metastatic prostate cancer.

In this report, we describe the distribution of metastases from 14 patients who had hormone-refractory adenocarcinoma of the prostate and agreed while alive to undergo directed autopsies after their deaths. These autopsies were undertaken specifically to document the distribution of metastases, characterize tumors phenotypically and immunohistochemically, harvest fresh and snap frozen tumor and normal control tissues suitable for molecular examination, and establish cell lines via passages through generations of severe combined immunodeficient and athymic mice. Achievement of these goals was obtained through the development of a multidisciplinary team approach. Team members included a medical oncologist, pathologists, urologists, and researchers. The autopsy and tissue procurement teams were available on a round-the-clock basis. The tissues harvested from these autopsies yielded high-quality tumor samples, as evidenced by excellent preservation seen by light microscopy, strong prostate-specific antigen immunostaining, and the successful development of xenografts. The development and expansion of this program represent a valuable resource for molecular and clinical researchers.

Aged↗

Common mutations in BRCA1 and BRCA2 do not contribute to early prostate cancer in Jewish men.

BACKGROUND: Families with a high incidence of hereditary breast cancer, and subsequently shown to have terminating mutations in BRCA1 or BRCA2, appear to have a higher incidence of prostate cancer among male relatives. We aimed to determine whether the common germline mutations of BRCA1 or BRCA2 in Ashkenazi Jewish men predisposed them to prostate cancer. METHODS: We examined genomic DNA from 83 (for BRCA1 185delAG) or 82 (for BRCA2 6174delT) Ashkenazi Jewish prostate cancer patients, most of whom were treated at a relatively young age, for the most common germline mutation in each gene seen in the Ashkenazi population. RESULTS: Our study should have been able to detect a 4-5-fold increase in the risk of prostate cancer due to mutation of BRCA1 or BRCA2. However, only one (1.15%; 95% confidence interval, 0-3.6%) of the patients was heterozygous for the BRCA1 mutant allele, and only two were heterozygous for the BRCA2 mutation (2.4%; 95% confidence interval, 0-6.2%). CONCLUSIONS: The incidence of each of the germline mutations in these prostate cancer patients closely matched their incidence (about 1%) in the general Ashkenazi Jewish population. This suggests that unlike cases of breast and ovarian cancers, mutations in BRCA1 or BRCA2 do not significantly predispose men to prostate cancer.

Adult↗

The detection of renal carcinoma cells in the peripheral blood with an enhanced reverse transcriptase-polymerase chain reaction assay for MN/CA9.

BACKGROUND: Using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay, the authors previously determined the expression of MN/CA9 mRNA in renal cell carcinoma (RCC) and its absence in benign renal tissue. In the current study, the utility of an enhanced RT-PCR assay in the detection of renal carcinoma cells in the peripheral blood was assessed. METHODS: An enhanced MN/CA9 RT-PCR assay was applied to peripheral blood samples from a total of 96 patients. Forty-two patients had renal tumors, including 5 with benign renal lesions, 28 with localized RCC, and 9 with metastatic RCC. Fifty-four control patients without renal tumors were similarly tested. Pathologic staging for patients with localized cancer was T1N0M0 for 5, T2N0M0 for 9, and T3N0M0 for 14 patients. RESULTS: Cells expressing MN/CA9 were detected in 1 of 54 controls (1.8%) and in 18 of 37 cancer patients (49%). Thirteen of twenty eight patients (46%) with localized RCC and 5 of 9 (56%) with metastatic disease tested positive with the assay. No patient with a benign renal tumor exhibited MN/CA9 expression. All blood test results for patients with clear cell RCC were noted to be positive. No correlation was noted between MN/CA9 results and age, gender, or tumor grade. The differences in MN/CA9 results according to T classification were not statistically significant. CONCLUSIONS: The enhanced RT-PCR assay for MN/CA9 is a highly specific technique for detecting circulating renal carcinoma cells in the peripheral blood, and it may prove useful in the diagnosis and monitoring of RCC.

Adult↗

Microvessel density in prostate cancer: lack of correlation with tumor grade, pathologic stage, and clinical outcome.

OBJECTIVES: Angiogenesis is believed to play an important role in tumor progression and metastasis. Previous studies have suggested that the microvessel density (MVD) of prostate tumors may be of prognostic value. This study investigated the reliability of assessing MVD in radical prostatectomy specimens and its value as an independent prognostic indicator in men with clinically localized prostate cancer. METHODS: One hundred radical prostatectomy specimens from 1993 to 1995 were randomly selected for this study. Thirteen cases were excluded because the patients had undergone neoadjuvant hormonal therapy or tissue blocks were unavailable. The median follow-up time was 36 months. Tumor blocks were immunostained using the endothelial-specific antibody CD31. MVD was counted in areas with the greatest microvessel immunostaining, which were designated "hot spots." MVD was analyzed for associations with clinical and pathologic factors. In a subset of 60 cases, the same observer repeated the counts three times. RESULTS: Intraobserver reliability for MVD counting was excellent (reliability coefficient 0.82), demonstrating that this method could be reproduced by a single observer. MVD was not associated with Gleason sum, tumor stage, surgical margin status, or seminal vesicle invasion. Of the 87 patients, 20 (23%) had a prostate-specific antigen (PSA) failure during a 36-month median follow-up time. As expected, Gleason sum and tumor stage were strong predictors of PSA failure, with risk ratios of 2.1 and 2.3, respectively. In contrast, MVD was not associated with PSA failure. CONCLUSIONS: MVD, as determined by CD31, can be reliably measured by a single observer, but it is not a useful prognostic indicator for men with clinically localized prostate cancer.

Aged↗

Perineural invasion on prostate needle biopsy: an independent predictor of final pathologic stage.

OBJECTIVES: To examine the significance of perineural invasion (PNI) in predicting pathologic findings in patients treated by radical prostatectomy, because a recent study concluded that PNI on needle biopsy has no independent predictive value. METHODS: Between 1993 and 1998, radical prostatectomy was performed in 319 consecutive patients. Prostate needle biopsies were reviewed in all cases. We compared PNI with other preoperative parameters, including digital rectal examination, PSA, and biopsy Gleason score, for the ability to predict tumor stage. Clinical records and pathologic findings were reviewed for all cases. Tumor stage was defined as either pT2 (organ confined) or pT3 (extraprostatic extension and/or seminal vesicle invasion). RESULTS: The median age was 61.4 years (range 40 to 75.6). Seventy-two percent of the 95 men with nonpalpable disease and 67% of the 224 men with palpable disease had organ-confined prostate cancer on final pathologic staging. Of 205 men with a Gleason score on biopsy of 6 or less, 159 (78%) had organ-confined disease compared with 59 (52%) of 114 with a Gleason score of 7 to 9 (P <0.001, chi-square test). PNI was identified in 77 (24%) of 319 patients, with 83% specificity and 40% sensitivity for Stage pT3 disease (odds ratio 3.49). Of men with pT3 disease on final pathologic staging, 18%, 27%, and 56% had preoperative PSA levels of 0 to 4, more than 4 to 10, and greater than 10 ng/mL, respectively (P <0.001, Mantel-Haenszel chi-square test). On multivariate analysis, PNI (P = 0.0031), PSA (P = 0.0004), and Gleason score (P = 0.0003) independently predicted stage (pT3 disease). CONCLUSIONS: PNI is an important preoperative predictor of pathologic stage and should be reported when adenocarcinoma is diagnosed on prostate needle biopsies.

Adult↗

Effects of lead on adenylate cyclase activity in rat cerebral cortex.

Lead decreased in a dose dependent manner the basal AC activity in membranes of rat cerebral cortex (IC50 = 2.5 +/- 0.1 microM). In membranes preincubated under basal conditions, AC activity was stimulated by approximately two and fourfold by 10 microM Gpp(NH)p or forskolin, respectively. Under basal conditions, lead (3 microM) inhibited enzyme activity up to 50%, but was not able to inhibit the Gpp(NH)p- or the forskolin-stimulated AC activity. However, in membranes preincubated with Gpp(NH)p (10 microM), lead (3 microM) had no significant effect on enzyme activity, but it partly blocked the stimulation of AC activity elicited by forskolin (10 microM). In membranes preincubated with 10 microM lead, the addition of 10 microM Gpp(NH)p or forskolin in the incubation medium did not stimulate AC activity. However, when added together in the incubation medium Gpp(NH)p + forskolin produced an increase in enzyme activity. In membranes preincubated with 10 microM lead + 10 microM Gpp(NH)p, Gpp(NH)p (10 microM) or forskolin (10 microM) added alone or in combination to the incubation medium did not stimulate AC activity. Moreover, under these latter conditions lead had no further effect on enzyme activity. These results indicate that lead may interact with G-proteins and with the catalytic subunit of cerebral cortical AC to produce inhibition of the enzyme activity.

Adenylyl Cyclases↗