Serum prostate specific antigen levels in mice bearing human prostate LNCaP tumors are determined by tumor volume and endocrine and growth factors.

The ability of prostate-specific antigen (PSA) to predict tumor volume and stage in patients with prostate cancer would be improved if factors regulating its production and clearance were better defined. A thorough understanding of the pharmacokinetics (regulation of production, metabolism, and excretion) of PSA has been precluded, however, by the absence of an in vivo animal model. The purposes of this study are to develop a murine model for evaluating PSA pharmacokinetics in vivo and to assess factors that influence PSA production in vitro. The human prostate cancer cell line, LNCaP, was chosen because it is androgen sensitive and PSA positive. Although LNCaP cells are usually nontumorigenic when inoculated s.c. in athymic mice, coinoculation of 1 x 10(6) LNCaP cells with 1 x 10(6) human bone fibroblasts reliably produces PSA-secreting carcinomas. This LNCaP model provides accurate correlation between tumor volume and serum PSA levels (r = 0.94) and demonstrates that tumor volume and androgens are codeterminants of circulating PSA levels. Following castration, serum PSA levels decrease rapidly up to 8-fold and increase up to 20-fold following androgen supplementation, without detectable castration-induced tumor cell death or concomitant changes in tumor volume. Serum PSA levels increase 0.24 ng/ml/mm3 of tumor, which is approximately 5-fold less than that estimated for humans. Most likely this reduced PSA index (PSA:tumor volume ratio) results from a 7-fold faster clearance of PSA in athymic mice than in humans; other than this shorter half-life, PSA elimination in the murine model appears similar to that in humans, with both following first-order kinetics characteristic of a two-compartment model. Interestingly, following prolonged growth (greater than 21 days) in castrate hosts, LNCaP tumors are capable of adapting to an androgen-deprived environment whereby LNCaP tumors regain the ability to secrete PSA in amounts similar to the precastrate state. In LNCaP cells, androgens increase PSA mRNA levels 4-fold in vivo and in vitro. PSA mRNA expression is also altered by various growth factors. Changes in PSA production induced by androgens and growth factors do not always parallel changes in LNCaP cell growth rate induced by these factors, suggesting that PSA production occurs independently of cell growth rate and may be influenced by various interrelated factors, including hormonal and stromal milieu. Observations from this murine model suggest that androgens and tumor volume are independent determinants of serum PSA levels and imply that decreases in circulating PSA following antiandrogen therapy may not always reflect a corresponding reduction in tumor volume.     

Inhibitory effects of evodiamine on the growth of human prostate cancer cell line LNCaP

Evodiamine, isolated from a Chinese herbal drug named Wu-Chu-Yu, possesses many biological functions. Recently, it has been reported that Wu-Chu-Yu exerts an antiproliferative effect on several cancers. Prostate carcinoma initially occurs as an androgen-dependent tumor and is the second leading cause of cancer death in American males. In the present study, the effect of evodiamine on the growth of androgen-dependent prostate cancer cell line LNCaP in vitro was examined. Based on [3-(4,5-dimethylthiazol-2-yle)2,5-diphenyltetrazolium bromide] (MTT) assay, evodiamine significantly inhibited the growth of LNCaP cells in a concentration-dependent manner. A significant and concentration-dependent inhibitory effect of evodiamine on LNCaP cell growth was observed at 24 hr and persisted for 96 hr. The examination of lactate dehydrogenase (LDH) assay showed that the cytotoxic effects of evodiamine on LNCaP cells were concentration dependent. Furthermore, we examined the influences of evodiamine on cell death and cell cycle. The flow cytometric analysis of evodiamine-treated cells indicated a block of G2/M phase and an elevated level of DNA fragmentation. The G2/M arrest reached a maximum at 24 hr after evodiamine treatment. The G2/M arrest was accompanied by an elevated p34(cdc2) kinase activity and an increase in the protein expression of cyclin B1 and phosphorylated form of p34(cdc2) (Thr 161). Examination of TUNEL showed that evodiamine-induced apoptosis was observed at 24 hr and extended for 72 hr. Evodiamine elevated caspase-3, and caspase-9 activities and the processing of caspase-3 and caspase-9. These results suggested that evodiamine inhibits the growth of prostate cancer cell line, LNCaP, through an accumulation of cell cycle at G2/M phase and an induction of apoptosis.     

Co-expression and impact of prostate specific membrane antigen and prostate specific antigen in prostatic pathologies

Background

The present study was undertaken to relate the co-expression of prostate-associated antigens, PSMA and PSA, with the degree of vascularization in normal and pathologic (hyperplasia and cancer) prostate tissues to elucidate their possible role in tumor progression.

Methods

The study was carried out in 6 normal, 44 benign prostatic hyperplastic and 39 cancerous human prostates. Immunohistochemical analysis were performed using the monoclonal antibody CD34 to determine the angiogenic activity, and the monoclonal antibodies 3E6 and ER-PR8 to assess PSMA and PSA expression, respectively.

Results

In our study we found that in normal prostate tissue, PSMA and PSA were equally expressed (3.7 ± 0.18 and 3.07 ± 0.11). A significant difference in their expression was see in hyperplastic and neoplastic prostates tissues (16.14 ± 0.17 and 30.72 ± 0.85, respectively) for PSMA and (34.39 ± 0.53 and 17.85 ± 1.21, respectively) for PSA. Study of prostate tumor profiles showed that the profile (PSA+, PSMA-) expression levels decreased between normal prostate, benign prostatic tissue and primary prostate cancer. In the other hand, the profile (PSA-, PSMA+) expression levels increased from normal to prostate tumor tissues. PSMA overexpression was associated with high intratumoral angiogenesis activity. By contrast, high PSA expression was associated with low angiogenesis activity.

Conclusion

These data suggest that these markers are regulated differentially and the difference in their expression showed a correlation with malignant transformation. With regard to the duality PSMA-PSA, this implies the significance of their investigation together in normal and pathologic prostate tissues.     

Evaluation of free-to-total prostate specific antigen ratio in the diagnosis of prostate cancer

It'sreportedthatfreetototalprostatespecificantigenration(f/tPSA)canprovidemorebenefitthanthesingleuseofprostatespecificantigen(PSA)inthediagnosisofprostatecancer(PCa).WemeasuredserumPSAandfPSAlevelsin62casesofbenignprostatichyperplasia(BPH)and40casesofPCausingradioimmunoassay,withpatients'agerange59y-89y.RESULTSPSA,fPSAandf/tPSAareshowninTable1.BoththesetwogroupsshowslinearcorrelationbetweenPSAandfPSA,correlationcoefficientofBPHis0.55(P<0.01),ofPCais0.44(P<0.01).Twoslopesha…     

Inhibition of tumorigenic potential and prostate-specific antigen expression in LNCaP human prostate cancer cell line by 13-cis-retinoic acid

Prostate-specific antigen (PSA) is a member of the kallikrein family and has been an important biological marker for prostate cancer. The mechanisms regulating PSA expression in prostatic cancer cells are unclear. The present study was designed to elucidate the role of 13-cis-retinoic acid (RA) in regulation of PSA and the tumorigenic potential of the human prostate cancer cell line LNCaP. The growth regulation of LNCaP cells was examined by DNA synthesis and doubling time. The tumorigenic potential of prostate cancer cells was analyzed by soft agar colony-forming assay, in vitro invasion assay, type IV collagenase assay and binding to extracellular matrix assay. The nuclear receptors for retinoic acid (RARα, -β, -γ and RXRα, -β,-γ) as well as PSA mRNA were determined by Northern blot using specific oligonucleotide probes. Our results suggest that 13-cis-RA significantly inhibits PSA secretion and expression both at the mRNA and protein levels compared with untreated cells. Electron microscopic studies suggest that after 13-cis-RA treatment, cells become more differentiated as they contain lumina, lined by plasma membrane and microvilli. Prostate cancer cell growth and tumorigenic potential after 13-cis-RA treatment was significantly decreased compared with controls. Nude mice tumorigenicity studies showed that 13-cis-RA-treated cells produced significantly smaller tumors compared with untreated cell tumors. There was also a significant increase in the expression of RXRa mRNA after 13-cis-RA treatment compared with untreated cells.     

Inhibition of prostate specific antigen expression by genistein in prostate cancer cells

Recent studies have provided convincing evidence for the role of soy-isoflavones, particularly genistein, in the inhibition of prostate cancer cell growth. Prostate specific antigen (PSA) is a biological marker used to detect and monitor the treatment of prostate cancer patients. Previous studies have documented that isoflavones can inhibit the secretion of PSA in the androgen-dependent prostate cancer cell line, LNCaP, however, the effects of genistein on androgen-independent PSA expression has not been explored. In this study, we have utilized a prostate cancer cell line, VeCaP, which expresses PSA in an androgen-independent manner, to determine the effects of genistein on cell proliferation and PSA expression. Here we show that genistein inhibits cell growth similarly in both the LNCaP and VeCaP cell lines, but has differential effects on PSA expression. We demonstrate using concentrations of genistein that have been detected in the serum of humans consuming a soy-rich diet, that genistein decreases PSA mRNA, protein expression and secretion. Conversely, only high concentrations of genistein inhibited PSA expression in VeCaP cells. Additionally, we have demonstrated that genistein inhibits cell proliferation independent of PSA signaling pathways, providing further evidence to support the role of genistein as a chemopreventive/therapeutic agent for prostate cancer irrespective of androgen responsiveness.     

前列腺癌患者治疗前后PSA水平

目的　探讨PSA在前列腺癌临床诊疗中的应用价值。方法　采用ELISA法测定 3 3例健康者、3 6例良性前列腺增生及 3 3例前列腺癌治疗前后T PSA和F PSA并动态观察 2 0例放疗后T PSA水平变化。结果　前列腺癌T PSA和F PSA、F/T均显著高于良性前列腺增生 (P <0 .0 1) ;前列腺癌治疗后T PSA和F PSA显著下降 (P <0 .0 1) ,而F/T无明显改变 (P >0 .0 5 ) ;前列腺癌放疗后病情稳定T PSA下降 ,病情进展则T PSA升高。结论　动态测定前列腺癌患者治疗前后PSA水平变化 ,可判断近期疗效 ,监测病情变化。     

Knockdown of STEAP1 inhibits cell growth and induces apoptosis in LNCaP prostate cancer cells counteracting the effect of androgens

Six transmembrane epithelial antigen of the prostate 1 (STEAP1) is overexpressed in numerous types of tumors, especially in prostate cancer. STEAP1 is located in the plasma membrane of epithelial cells and may play an important role in inter- and intracellular communication. Several studies suggest STEAP1 as a potential biomarker and an immunotherapeutic target for prostate cancer. However, the role of STEAP1 in cell proliferation and apoptosis remains unclear. Therefore, the role of STEAP1 in prostate cancer cells proliferation and apoptosis was determined by inducing STEAP1 gene knockdown in LNCaP cells. In addition, the effect of DHT on the proliferation of LNCaP cells knocked down for STEAP1 gene was evaluated. Our results demonstrated that silencing the STEAP1 gene reduces LNCaP cell viability and proliferation, while inducing apoptosis. In addition, we showed that the cellular and molecular effects of STEAP1 gene knockdown may be independent of DHT treatment, and blocking STEAP1 may reveal to be an appropriate strategy to activate apoptosis in cancer cells, as well as to prevent the proliferative and anti-apoptotic effects of DHT in prostate cancer.     

Prostate specific antigen complexed to alpha-1-antichymotrypsin in patients with intermediate prostate specific antigen levels

BACKGROUND: The authors attempted to evaluate prospectively the usefulness of serum prostate specific antigen (PSA) complexed to alpha-1-antichymotrypsin (PSA-ACT) in the early detection of prostate carcinoma and its ability to discriminate between prostate carcinoma and benign prostatic hyperplasia (BPH), especially among patients with intermediate PSA levels. METHODS: Between December 1999 and August 2000, systematic sextant biopsies were performed on 281 prospective patients with prostate carcinoma who had serum PSA levels between 4.1 ng/mL and 20.0 ng/mL. The serum samples were assayed by using kits that were designed specifically for measuring serum PSA, PSA-ACT, and free PSA levels. The clinical values of PSA, PSA-ACT, the free PSA to total PSA ratio (F/T ratio), the free PSA to PSA-ACT ratio, PSA density (PSAD), and PSA-ACT density (ACTD) were compared by using receiver operating characteristic (ROC) curve analysis. RESULTS: Biopsy yielded no evidence of malignancy in 198 patients, and prostate carcinoma was confirmed in 83 patients. ROC analysis demonstrated that the area under the curve (AUC) for PSA-ACT was greater than that for total PSA and was equivalent to that for the F/T ratio in both groups of patients (PSA ranges of 4.1-20.0 ng/mL and 4.1-10.0 ng/mL, respectively). The AUC for the ACTD was greater than the AUC for the PSAD and had the highest value of all parameters. CONCLUSIONS: The measurement of PSA-ACT represents an alternative to the use of total and free PSA. The ACTD value is the most useful for discriminating between BPH and prostate carcinoma.     

Induction of prostate specific antigen production by steroids and tamoxifen in breast cancer cell lines

Summary We demonstrate that the steroid hormone receptor-positive breast carcinoma cell lines T-47D and MCF-7 can be induced by androgens, progestins, mineralocorticosteroids, glucocorticosteroids, and antiestrogens, to produce prostate specific antigen (PSA). Estrogens failed to induce such stimulation in both cell lines and, in addition, were able to block the induction by androgens in the cell line T-47D. These data support and extend our previous report on PSA production by breast tumors and describe anin vitro system which can be used to study the phenomenon for possible application in prognosis and design of new therapy.     

游离型PSA时间分辨荧光免疫分析法的建立

目的：建立血清游离型前列腺特异性抗原（F-PSA）的时间分辨荧光免疫分析法（TRFIA）.方法：以抗PSA单克隆抗体101#包被96孔微孔板,用Eu3＋标记抗 F-PSA单克隆抗体201#,夹心法建立F-PSA的时间分辨荧光免疫分析法.标准曲线由TRFIA检测仪自带的Log-Log_B函数处理.结果：F -PSA批内和批间CV分别为1.12%和5.36%,效点均值ED20、ED50和ED80分别为2.866、12.01和38.13 ng/mL.可测范围为0.02～78 ng/mL.回收率为103.58%.试剂经冻干后-30 ℃保存6个月后免疫反应参数基本未改变.结论：建立的F-PSA TRFIA有良好的健全性,定量分析效果较好.     

应用前列腺特异抗原筛查诊断前列腺癌的临床意义

Objective To evaluate the clinical significance of prostate-specific antigen(PSA)screening in early detection of prostate cancer in Chinese men.Methods PSA screening was performed in 8562 asymptomatic men who had been enrolled for health checkup and all were ≥50 years old.Prostate biopsy was recommended for those with a serum PSA level≥4.0 ng/ml.The pathological and clinical features of the patients with prostate cancer detected by the PSA screening were compared with that of 82 clinically diagnosed prostate cancer patients during the same period.Results Of the 8562 asymptomatic men,719 had PSA levels ≥4.0 ng/ml and biopsy was performed in 295 of them.Fifty-eight prostate cancers were detected.The biopsy rate was 41.0% and positive detection rate was 19.7%.The overall age distribution in the screening group and the clinical groups was not significantly different(P = 0.176).However,41.4%(24/58)of the patients in screening group were ＞75 years old,and significantly more than that in the clinical group(25.6%,P = 0.0491).The proportion of the patients with PSA levels ≥20 ng/ml in the screening group was significantly less than that in the patients of the clinical group(44.8% vs.75.6%,P = 0.0002).Whether in the patients whose age was ＞ 75 years old(P ＜ 0.05)or ≤75 years old (P = 0.0002),the patients in the screening group had significantly lower Gleason scores ＜ 7(60.3% vs.34.1%,P =0.002),more T1 or T2 tumor(87.9% vs.26.8%,P ＜0.0001)and more chance to receive radical prostatectomy(50.0% vs.18.3%,P ＜ 0.0001)than the patients in the clinical group did.However,the distributions of PSA levels at diagnosis and biopsy Gleason scores were not significantly different between the above mentioned two groups(P ＞ 0.05).Conclusion Prostate-specific antigen (PSA)screening is useful for early detection of prostate cancer in Chinese men aged ≥ 50 years.The patients detected by PSA screening usually show a lower PSA level,Gleason scores and early clinical stage disease,and have more chance for radical prostatectomy than the clinically diagnosed patients.     

应用前列腺特异抗原筛查诊断前列腺癌的临床意义

目的 探讨应用前列腺特异抗原(PSA)筛查诊断前列腺癌的临床意义.方法 对年龄≥50岁的8562例男性体检者进行PSA筛查,对血清PSA≥4.0 ng/ml者建议进行经直肠前列腺系统活检,活检病理确诊为前列腺癌的患者人选筛查组,记录其临床病理特点,并与同时期临床诊治的82例前列腺癌患者(临床组)进行比较.结果 在8562例进行血清PSA筛查的男性中,有719例血清PSA水平≥4.0 ng/ml,其中295例接受经直肠前列腺系统活检,共检出前列腺癌58例,活检率和活检阳性率分别为41.0%和19.7%.虽然两组患者的年龄分布差异无统计学意义(P=0.176),但筛查组中有41.4%(24/58)的患者年龄＞75岁,明显高于临床组(25.6%,P=0.0491).筛查组中血清PSA水平≥20.0 ng/ml的患者所占的比例为44.8%,明显低于临床组(75.6%,P＜0.0001).筛查组中活检Gleason评分＜7分的患者所占的比例为60.3%,明显高于临床组(34.1%,P=0.0020).筛查组中临床分期为T1和T2期(局限期)患者所占的比例为87.9%,明显高于临床组(26.8%,P＜0.0001).筛查组中接受根治性前列腺切除术的患者所占的比例为50.0%,明显高于临床组(18.3%,P＜0.0001).在年龄≤75岁的患者中,筛查组患者诊断时的血清PSA水平、活检Gleason评分和临床分期均显著低于临床组(均P＜0.05);在年龄＞75岁的患者中,筛查组患者的临床分期也明显低于临床组(P=0.0002),但两组诊断时血清PSA水平和活检Gleason评分的差异并无统计学意义(均P＞0.05).结论 应用血清PSA在我国50岁以上男性中进行前列腺筛查是有效的.筛查出的前列腺癌患者在血清PSA水平、活检Gleason评分、临床分期以及根治性切除的机会等方面均较临床组有明显优势.     

The prognostic significance of prostate specific antigen in metastatic hormone-resistant prostate cancer.

Twenty-seven of 152 patients (18%) with progressing hormone resistant prostate cancer had normal serum levels of prostate specific antigen (PSA less than or equal to 10 micrograms l-1), when referred for secondary treatment. PSA was significantly correlated with the extent of skeletal metastases (R: 0.35) and the levels of hemoglobin (R: -0.19) and serum alkaline phosphatase (R: 0.30). In a multivariate Cox regression analysis the survival of the 152 patients was not correlated with the PSA level but with the patients performance status, the level of hemoglobin, and the time between primary hormone treatment and relapse. The lack of serum PSA to predict survival may be explained by a heterogenous composition of hormone resistant prostate cancer as regards differentiated and/or PSA producing vs undifferentiated and/or PSA non-producing cells.     

PSAT 在前列腺穿刺活检中的意义

目的:探讨前列腺移行带特异性抗原密度(PSAT)在前列腺穿刺活检中的意义。方法:对120例患者行前列腺穿刺活检,其中PSA≥4ng/ml者105例,PSA<4ng/ml且直肠指诊及经直肠B超有阳性发现者15例。对PSA、PSAD和PSAT与前列腺穿刺活检的关系进行分析。结果:120例患者中经前列腺穿刺诊断为前列腺癌(PCa)63例,活检阳性率52.5,其中15例PSA<4ng/ml者中,活检结果为前列腺横纹肌肉瘤1例,前列腺小细胞癌2例,腺癌4例,良性前列腺增生8例;42例>20ng/ml者中32例为PCa,活检阳性率76.2;63例PSA4-20ng/ml者中24例为PCa,活检阳性率38.1;29例PSA4-10ng/ml者中10例为PCa,活检阳性率34.5。血清PSA4-20ng/ml患者,PSAD≥0.13或PSAT≥0.15时,敏感性均为100,特异性为20.5或17.9,阳性预测值为43.6或42.9,可避免12.7(8/63)或11.1(7/63)阴性穿刺结果。血清PSA4-20ng/ml时,前列腺穿刺阳性组和阴性组PSA分别为11.18±4.49和10.05±4.29ng/ml(P=0.318);PSAD分别为0.45±0.33和0.26±0.15(P=0.003);PSAT分别为0.94±0.65和0.43±0.24(P=0.000)。血清PSA、PSAD和PSAT的ROC曲线下面积分别为0.576、0.676和0.77,PSAT的ROC曲线下面积与PSA比较,差异均有统计学意义(P<0.05)。结论:PSA4-20ng/ml时,PSAT对预测患者是否行前列腺穿刺活检有较大帮助。     

Effects of docosahexaenoic acid and eicosapentaenoic acid on androgen-mediated cell growth and gene expression in LNCaP prostate cancer cells

There is some epidemiological support for a protective influence of omega-3 fatty acids against prostate cancer. We wanted to explore whether omega-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) can affect androgen receptor function in prostate cancer cells. Our study showed that both DHA and EPA inhibit androgen-stimulated cell growth. Androgenic induction of prostate-specific antigen (PSA) protein was repressed by DHA and EPA in a dose-dependent manner. The mRNA levels of five androgen up-regulated genes, PSA, ornithine decarboxylase, NKX 3.1, immunophilin fkbp 51 and Drg-1, were decreased with DHA treatment in the presence of androgens. Transfection experiments using a DNA vector containing androgen-responsive elements demonstrated that both DHA and EPA could interfere with transactivation activities of the androgen receptor (AR). However, western blot analysis of AR protein showed that DHA and EPA treatments did not change AR expression levels. Interestingly, the proto-oncoprotein c-jun was increased by DHA treatment. A transient transfection found that forced expression of c-jun inhibited AR transactivation activity. Thus, this study found that the inhibitory effects of omega-3 polyunsaturated fatty acids on AR-mediated actions are due, at least in part, to an increase in c-jun protein.