Vascular endothelial growth factor content in metastasizing and nonmetastasizing Dunning prostatic adenocarcinoma

BACKGROUND

Tumor angiogenesis is important in progressive tumor growth and metastasis. In the normal rat prostate and in androgen-sensitive prostate tumors androgen ablation causes an involution of the vasculature and a decrease in the vascular endothelial growth factor (VEGF) levels before regression of the prostate gland. To examine whether angiogenesis and metastasis are regulated by VEGF in androgen-insensitive and metastasizing prostate tumors, five Dunning rat prostate cancer sublines were tested; the androgen-sensitive, nonmetastasizing R3327 PAP, and the androgen-insensitive, low metastasizing AT-1, and the three androgen-insensitive, metastasizing AT-2, AT-3, and MatLyLu Dunning prostatic adenocarcinomas.

METHODS

VEGF levels were quantified in the rat dorsolateral prostate and in the five Dunning sublines using competitive RT-PCR, Western blot, and Elisa. Vascular density was determined by factor VIII staining.

RESULTS

VEGF mRNA was increased in all tumors compared with normal prostates. The two metastatic sublines AT-3 and MatLyLu and the nonmetastatic subline AT-1 showed the highest VEGF mRNA expression. VEGF protein levels in the prostate gland showed increased expression in the metastatic sublines, AT-2, AT-3, and MatLyLu, compared with the nonmetastatic AT-1 subline and the ventral prostate. VEGF proteins in serum were highest in the metastatic AT-3 subline. The vessel density was highest in the two highly metastatic sublines AT-3 and MatLyLu.

CONCLUSIONS

Our results suggest that VEGF levels are associated with microvessel density and the previously established metastatic pattern of these rat prostate tumor systems.

Cancer risk in families with hereditary prostate carcinoma

BACKGROUND

Little is known regarding the clinical features of hereditary prostate carcinoma (HPC) and whether other malignancies are associated with this disease. The aim of this study was to investigate whether tumors other than prostate carcinoma aggregate in families with HPC or whether this disease can be considered site specific.

METHODS

From 62 Swedish families with HPC, a cohort was constructed of 1364 first-degree relatives of the men with prostate carcinoma in these families. Through linkage to the Swedish Cancer Register, all reported cancer between 1958 and 1996 was identified. The expected number of cases was calculated by using the population rates in Sweden.

RESULTS

A standardized incidence ratio (SIR) of 1. 16 (95% confidence interval [95% CI], 0.97-1.38) for the overall cancer risk was observed among the 1364 first-degree relatives. However, significant increased risks were noticed for gastric carcinoma (SIR, 2.78; 95% CI, 1.59-4.52), for breast carcinoma in women (SIR, 1.58; 95% CI, 1.01-2.35), and for kidney carcinoma (SIR, 2.51; 95% CI, 1.15-4.77).The excess risk for breast carcinoma was even more pronounced among women before the age of 65 years in families with earlier onset prostate carcinoma (SIR, 3.64; 95% CI, 1. 66-6.91). Seven families with at least two or more relatives with breast, gastric, or kidney carcinoma were identified, and, in one family, four relatives with early onset gastric carcinoma were observed.

CONCLUSIONS

In most of the families with HPC, the disease appears to be "site specific," with no excess of other malignancies. However, in a subset of families, a significant aggregation of prostate carcinoma together with breast carcinoma and/or gastric carcinoma was observed that may have been caused by a common germline mutation in a cancer susceptibility gene.

Application of the 5'-nuclease PCR assay in evaluation and development of methods for quantitative detection of Campylobacter jejuni

Campylobacter jejuni is recognized as a leading human food-borne pathogen. Traditional diagnostic testing for C. jejuni is not reliable due to special growth requirements and the possibility that this bacterium can enter a viable but nonculturable state. Nucleic acid-based tests have emerged as a useful alternative to traditional enrichment testing. In this article, we present a 5'-nuclease PCR assay for quantitative detection of C. jejuni and describe its evaluation. A probe including positions 381121 to 381206 of the published C. jejuni strain NCTC 11168 genome sequence was identified. When this probe was applied, the assay was positive for all of the isolates of C. jejuni tested (32 isolates, including the type strain) and negative for all other Campylobacter spp. (11 species tested) and several other bacteria (41 species tested). The total assay could be completed in 3 h with a detection limit of approximately 1 CFU. Quantification was linear over at least 6 log units. Quantitative detection methods are important for both research purposes and further development of C. jejuni detection methods. In this study, we used the assay to investigate to what extent the PCR signals generated by heat-killed bacteria interfere with the detection of viable C. jejuni after exposure at elevated temperatures for up to 5 days. An approach to the reduction of the PCR signal generated by dead bacteria was also investigated by employing externally added DNases to selectively inactivate free DNA and exposed DNA in heat-killed bacteria. The results indicated relatively good discrimination between exposed DNA from dead C. jejuni and protected DNA in living bacteria.

Tumor associated macrophages in human prostate cancer: relation to clinicopathological variables and survival

Tumor associated macrophages (TAM) influence diverse processes such as angiogenesis, tumor cell proliferation, and metastasis during tumor progression. In a variety of tumor types, the amount of TAM has been associated with prognosis, but their role in prostate cancer has not been elucidated. The purpose of this study was to investigate the role of TAM in a series of 85 cases of prostatic carcinoma, diagnosed at transurethral resection of the prostate between 1975-1983, using immunohistochemistry and morphometrical techniques. Macrophage density was assessed as the maximum number of TAM per field in the three most macrophage dense areas (TAMmax) and as the average volume density of TAM in an estimate of the whole resected tumor. Furthermore, the individual cell profile area of TAM was assessed with an image analyzer. Macrophage variables were thereafter related to histological grade, tumor stage, metastasis as well as to vascular density, tumor cell proliferation and survival. Patients with a volume density of TAM in the fourth quartile had a shorter median cancer specific survival time than patients in the first to third quartile (3.3 vs. 5.9 years, p=0.005). Furthermore, an increased macrophage cell profile area was related to poor clinical outcome (4.6 vs. 5.9 years, p=0.039) whereas TAMmax gave no prognostic information. In a multivariate analysis, metastasis and the volume density of macrophages gave independent prognostic information (p=0.0008, p=0.010). However, when excluding metastasis from the analysis, only Gleason score was an independent predictor of cancer specific survival (p= 0.005). The volume density of TAM, the macrophage cell profile area and TAMmax increased with increasing Gleason score (p=0.001, p=0.0001, p=0.0001 respectively). A correlation was found between the volume density of TAM and tumor cell proliferation (rs=0.44, p=0.001) and an increased macrophage cell profile area was associated to microvessel density (rs=0.42, p=0.0001). Together these results suggest that both the functional state (as reflected by cell size), number and location of the macrophages are of importance for their influence on prostate tumors, but macrophage quantification is not a strong independent prognostic factor.

Toxaphene levels in salmon (Salmo salar) from the Baltic Sea

Three toxaphene congeners have been determined in salmon from the Swedish coastal environment using both supercritical fluid (SFE) and the traditional liquid/liquid extractions. The levels obtained using a modifier-free SFE technique, followed by group separation on a silica gel column, were by far much lower than concentrations obtained by SFE with a modifier or liquid/liquid extraction. The mean concentrations on fresh weight basis using a liquid/liquid extraction technique were 5.87, 8.70 and 1.59 microg/kg for CHBs 26, 50 and 62, respectively. There was a plausible relationship between the various fishing sites and the toxaphene levels.

Evaluation of prognostic factors in prostate cancer with partial least squares analysis

OBJECTIVE

This study was carried out to explore the capability of partial least squares (PLS) analysis, a multivariate projection method, in the evaluation of investigative prognostic biomarkers.

MATERIAL AND METHODS

Using PLS analysis, survival and life expectancy were prognosticated in 53 patients with prostate cancer treated with transurethral resection. The age of the patient, stage and grade of the tumours, and immunoreactivity in the tumours for p53, Bcl-2, and TGF-beta1 and its receptors type I and type II (TGFbeta-RI and TGFalpha-RII), and markers for proliferation, vascular density, and macrophage density were included as prognostic factors in the analysis.

RESULTS

The prognostic impact of the factors, in decreasing order, was tumour grade, proliferation, stage, vascular density, TGFbeta-RI, metastasis, TGF-beta1, and TGFbeta-RII. Macrophage staining, p53, Bcl-2, and patient age did not contribute to the model. The model explained 62% of the total variance in survival, and the standard deviation of error of prediction was 29 months.

CONCLUSIONS

PLS analysis may become a useful tool for evaluation of putative prognostic factors.

Thoracic paravertebral block for breast surgery

Cosmetic and reconstructive breast augmentation is a frequently performed surgical procedure. Despite advances in medical treatment, surgical intervention is often associated with postoperative pain, nausea, and vomiting. Paravertebral nerve block (PVB) has the potential to offer long-lasting pain relief and fewer postoperative side effects when used for breast surgery. We compared thoracic PVB with general anesthesia for cosmetic breast surgery in a single-blinded, prospective, randomized study of 60 women scheduled for unilateral or bilateral breast augmentation or reconstruction. Patients were assigned (n = 30 per group) to receive a standardized general anesthetic (GA) or thoracic PVB (levels T1-7). Procedural data were collected, as well as verbal and visual analog pain and nausea scores. Verbal postoperative pain scores were significantly lower in the PVB group at 30 min (P = 0.0005), 1 h (P = 0.0001), and 24 h (P = 0.04) when compared with GA. Nausea was less severe in the PVB group at 24 h (P = 0.04), but not at 30 min or 1 h. We conclude that PVB is an alternative technique for cosmetic breast surgery that may offer superior pain relief and decreased nausea to GA alone.

IMPLICATIONS

Paravertebral nerve block has the potential to offer long-lasting pain relief and few postoperative side effects when used for breast surgery. We demonstrated that paravertebral nerve block, when compared with general anesthesia, is an alternative technique for breast surgery that may offer pain relief superior to general anesthesia alone.

Effects of finasteride and bicalutamide on prostatic blood flow in the rat

OBJECTIVE

To determine whether finasteride and bicalutamide, both currently used in the clinical management of patients with prostate diseases because they have anti-androgenic properties, have any effects on prostatic blood flow in a rat prostate model, as androgens are known to be involved in the regulation of prostatic blood flow and angiogenesis.

MATERIALS AND METHODS

Both finasteride and bicalutamide were supplied as oral suspensions in water and given daily to rats for 7 days by tube feeding. Blood flows to the ventral and dorsal prostates, and to the kidneys, were measured using the radioactive microsphere technique. In the bicalutamide experiments, some rats were treated with the Leydig cell toxin ethane dimethane sulphonate (EDS), to obtain a castration-like effect, and one group of these rats received testosterone.

RESULTS

Finasteride induced a clear decrease in blood flow to the ventral and dorsal prostates after 7 days of treatment, with no significant changes in blood pressure or kidney blood flow. Bicalutamide inhibited the testosterone-induced increment of prostatic blood flow observed in EDS-treated animals.

CONCLUSIONS

Finasteride, a blocker of 5alpha-reductase, decreases prostate blood flow after 7 days of administration. The response was slower than that after castration, but was of similar magnitude. Blood flow was also decreased after treatment with the androgen-receptor inhibitor bicalutamide. These observations suggest that prostatic blood flow is increased by dihydrotestosterone, and that the androgen receptor is responsible for mediating this effect.

Transforming growth factor-beta1 and prostate cancer

Transforming growth factor-beta1 (TGF-beta1) is an important regulator of the normal and malignant prostate. In the non-malignant prostate, TGF-beta1 stimulates cell differentiation, inhibits epithelial cell proliferation and induces epithelial cell death. TGF-beta1 is secreted into semen and here it is an important immunosuppressive factor. Prostate cancer cells express high levels of TGF-beta1 and it seems to enhance prostate cancer growth and metastasis by stimulating angiogenesis and by inhibiting immune responses directed against tumour cells. Prostate cancer cells frequently lose their TGF-beta receptors and acquire resistance to the anti-proliferative and pro-apoptotic effects of TGF-beta1. Accordingly, high expression of TGF-beta1 and loss of TGF-beta receptor expression have been associated with a particularly bad prognosis in human prostate cancer patients. TGF-beta1 also seems to be a mediator of castration-induced apoptosis in androgen dependent normal and malignant prostate epithelial cells. The ability of some prostate tumours to avoid castration-induced apoptosis is however not simply due to loss of TGF-beta receptor type I or II expression in the tumour cells, but may also be related to an inability of these cells to up-regulate TGF-beta receptor levels in response to castration or possibly due to defects downstream of the receptors. Short-term therapy-induced changes in the TGF-beta system in prostate tumours can probably be used to predict the long-term response to androgen ablation treatment. Further investigations into the TGF-beta system in the prostate are, however, needed to elucidate how alterations in this system affect the behaviour of prostate tumours, and if this system can be manipulated for therapeutical purposes.

Rye bran and soy protein delay growth and increase apoptosis of human LNCaP prostate adenocarcinoma in nude mice

BACKGROUND

In this study, we investigated whether dietary intervention could inhibit tumor growth of an androgen-sensitive human prostatic cancer.

METHODS

LNCaP cells were transplanted subcutaneously in nude-mice. The animals were then put on different diets and tumor take, tumor growth and prostate specific antigen (PSA) secretion were studied during 9 weeks.

RESULTS

Palpable tumors developed in 75% of the tumor-cell injected sites in animals fed a control diet (corn starch, sucrose, etc.) whereas, for animals given rye bran (RB), ethyl acetate extraction from rye bran supplemented cellulose based diets (CCEE), palpable tumors were seen in only 30% and for soy protein based diets (SCC) 50% of the transplantation sites, respectively. The tumors that grew to palpable size in the rye (RB) and soy (SCC) groups were smaller and secreted less PSA than those in the control group. In the rye and soy groups tumor cell apoptosis was increased, but cell proliferation was unaffected. Addition of fat to the rye diet reduced its effect on prostate cancer growth.

CONCLUSIONS

Factors in rye bran and soy protein may inhibit prostate cancer growth. The effect is more apparent for rye than for soy. Further studies are needed to identify the effective substances and to explore the mechanism of action.

A putative stimulatory role of progesterone acting via progesterone receptors in the steroidogenic cells of the human corpus luteum

To further explore the proposed auto-regulatory role of progesterone action in the human corpus luteum (CL), the expression and functional roles of progesterone receptor (PR) isoforms A and B during the luteal phase (LP) of the menstrual cycle were investigated. A total of 27 otherwise healthy patients previously scheduled for surgery were recruited after informed consent. An LH rise was detected, and CL were grouped according to age (Days 2-5 post-LH-rise, early LP; Days 6-10, mid LP; Days 11-14, late LP). Using a semiquantitative reverse transcription-polymerase chain reaction assay, the PR-B mRNA levels, which were 100- to 1000-fold lower than PR-A/B mRNA, were 46% lower (P < 0.05, n = 24) in mid LP, compared to early and late LP. CL tissue levels of progesterone and PR-A/B protein levels were inversely correlated to increasing CL age; i.e., significantly reduced levels were observed in the late LP (r(2) = 0.34, P < 0.01, n = 23). Expression of PR-A/B mRNA as well as PR-A/B protein were detected by in situ hybridization and immunohistochemistry, respectively. Both methods revealed a clear and distinct localization to cells in the steroidogenic layer of the CL. Freshly obtained mid-luteal CL cells were cultured in vitro, and media were analyzed for progesterone concentrations after treatment by incremental doses of hCG and the stable PR antagonist mifepristone, alone or in combination. Mifepristone did not per se alter progesterone synthesis, but when it was added in conjunction with hCG, a dose-related inhibitory response was seen, with a maximal 47% reduction in progesterone output at a 10 microM addition (P < 0.05, n = 3). Collectively, these data implicate a stimulatory role of progesterone receptor-mediated action in the steroidogenic cells of the human CL, which may serve as an important pathway for maintaining functional homeostasis during early pregnancy.

Radioimmunotherapy of DU-145 tumours in nude mice--a pilot study with E4, a novel monoclonal antibody against prostate cancer

The anti-tumour effect of the 131I-labelled antiprostate monoclonal antibody (MAb) E4 was studied in an experimental model with 41 nude mice, subcutaneously xenografted with a human prostate cancer cell line (DU-145). The mice were divided into four study groups, i.e. one receiving single and another repeated injections of the radiolabelled MAb. A third group was injected with non-labelled MAb, and the fourth served as an untreated control group. The tumour volumes increased similarly in all groups during the 27-day observation period. The tumour tissue was morphologically disintegrated in the group that received repeated radioimmunotherapy (RIT). The tumours from this group contained large fluid-filled cystic parts and demonstrated pronounced cellular and subcellular polymorphism in the remaining viable tumour tissue. The untreated control tumours and single therapy tumours remained solid. The proportion of the total tumour volume that consisted of viable tumour cells, as determined by morphometric techniques, was significantly lower in the 131I-E4-treated groups. The use of 131I-labelled E4 MAb has thus demonstrated a promising therapeutic potential.

Cigarette smoke and hypoxia induce acute changes in the testicular and cerebral microcirculation

The acute effects of cigarette smoking and hypoxia on the cerebral and testicular microcirculation were studied in anestethised adult rats. Smoking for 2 min did not influence arterial pO2, pCO2 or pH but it induced an increase in cerebral blood flow by 34% and inhibited vasomotion in the testis for about 1 h. One hour after smoke exposure apnea induced a slight increase in arterial pCO2, a significant decrease in pO2, and an increase in cerebral blood flow (CBF) by 54%. In animals not previously exposed to cigarette smoke apnea increased CBF by 121%, demonstrating that a short-term exposure to tobacco smoke influences the cerebrovascular reactivity for more than one hour. In the testis, apnea resulted in a decreased blood flow by 39% and a complete depression of vasomotion. Breathing 10% O2/90% N2 resulted in moderate hypoxia, a total disappearance of the vasomotion in the testis, a 24% decrease in testicular blood flow, but a 23% increase in CBF.

Erythrocyte-aggregating relapsing fever spirochete Borrelia crocidurae induces formation of microemboli

The African relapsing fever spirochete Borrelia crocidurae forms aggregates with erythrocytes, resulting in a delayed immune response. Mice were infected with B. crocidurae and monitored during 50 days after infection. Spirochetes were observed extravascularly at day 2 after infection. Two days later, inflammatory responses, cell death, and tissue damage were evident. The pathologic responses in lungs and kidneys were similar, whereas the symptoms in the brains were delayed, with a less pronounced inflammatory response. Microemboli were found in the blood vessels, possibly a result of the erythrocyte aggregation. The B. crocidurae invasion emerged more rapidly than has been described for Lyme disease-causing Borrelia species. In addition to erythrocyte rosetting, the presence of extravascular B. crocidurae indicates a novel route for these bacteria to propagate and cause damage in the mammalian host. The histopathologic findings in this study may explain the clinical manifestations of human relapsing fever.

Temporal variations in testicular microcirculation

Temporal variations in microcirculatory blood flow in the testis and blood pressure were examined in intact, pentobarbital-anesthetized rats with a two-channel laser Doppler flowmeter. The laser Doppler probes that measure local blood flow in a tissue volume of about 2 mm3 were placed either over the mid portion of the left and right testes or on the right testes 1 cm apart. Testicular microcirculation was characterized by a prominent vasomotion with a frequency of 5.3+/-1.4 cycles per minute and with an amplitude of 73+/-32% (mean +/- SD) of the mean. In addition to this large and rapid variation in local blood flow, there were also major variations from minute to minute in the average blood flow, vasomotion frequency, and vasomotion amplitude at 40 and 53 minutes. Such variations in local blood flow, vasomotion frequency, and vasomotion amplitude were correlated with each other at two different sites on the same testis (r(s) = 0.39, r(s) = 0.82, r(s) = 0.64, respectively, P < 0.001), and they were all correlated with systemic blood pressure (r(s) 0.41, r(s) = 0.61, r(s) = 0.32, respectively, P < 0.001). Minute-to-minute variations in local blood flow, vasomotion frequency, and vasomotion amplitude were also correlated between the right and left testes (r(s) = 0.58, r(s) = 0.75, r(s) = 0.57, respectively, P < 0.001). There are substantial temporal variations in testicular microcirculation. These variations are to some extent related to temporal changes in systemic blood pressure, but changes in the ultralocal environment are probably more important. The functional significance of, and the factors responsible for, local variations in testicular microcirculation remain to be elucidated.

After radiotherapy testosterone stimulation is unable to increase growth in the dunning R3327-PAP prostate tumour

A study was carried out to investigate whether testosterone treatment is able to influence tumour growth in a rat prostatic adenocarcinoma previously treated with castration and high-dose fractionated irradiation. Copenhagen x Fisher rats bearing the androgen-sensitive, well-differentiated Dunning R3327-PAP tumour were castrated and thereafter treated with external beam radiation with photons from a 4-MV linear accelerator. One month after irradiation, substitution with subcutaneous testosterone was started. Tumour volumes and rat weights were monitored up to 256 days after castration, and at the end of the study a microscopic analysis of the tumours was performed. Irradiation delayed tumour growth as compared with untreated tumours. Castration delayed tumour growth, but a hormone-refractory relapse to doubled tumour volume was seen within 45 days. If testosterone was added after castration, the tumours grew rapidly. However, testosterone failed to increase tumour growth when given to rats treated with orchiectomy and irradiation. Histological examination showed that the irradiated tumours still contained tumour epithelial cells, but these cells apparently do not respond to testosterone stimulation. The well-differentiated and androgen-sensitive rat prostatic adenocarcinoma did not grow after irradiation despite stimulation with testosterone. This indicates that the malignant cells lose their androgen sensitivity after high-dose irradiation.

A catheter tactile sensor for measuring hardness of soft tissue: measurement in a silicone model and in an in vitro human prostate model

Tissue hardness is related to tissue composition, and this is often changed by disease. It is therefore of interest to measure the hardness in an objective and non-invasive way. A tactile sensor based on a vibrating piezoelectric ceramic element in a feedback loop is described. When the sensor touches an object it produces a frequency shift related to the hardness of the object. The aim of this study was to develop an in vitro hardness measurement method using a catheter type version of the sensor. The method was evaluated in an established silicone tissue model and on human prostate tissue in vitro. A linear relationship was found with a high degree of explanation (R2 = 0.98) between a cone penetration hardness standard (DIN ISO 2137) applied to the silicone model and the corresponding frequency shift. The results from measurements on a human prostate tissue sample, fixed with formalin, showed that the relative hardness measured with the tactile sensor correlated (R = -0.96, p < 0.001, N = 60) with the proposed hardness related to the histological composition of the prostate tissue. The results indicated that hardness of prostate tissue, and maybe hardness of human tissue in general, can be expressed according to the cone penetration standard and that the hardness can be measured with this tactile sensory system. These findings hold the promise of further development of a non-invasive tool for hardness measurement in a clinical situation.

In Swedish families with hereditary prostate cancer, linkage to the HPC1 locus on chromosome 1q24-25 is restricted to families with early-onset prostate cancer

Prostate cancer clusters in some families, and an estimated 5%-10% of all cases are estimated to result from inheritance of prostate cancer-susceptibility genes. We previously reported evidence of linkage to the 1q24-25 region (HPC1) in 91 North American and Swedish families each with multiple cases of prostate cancer (Smith et al. 1996). In the present report we analyze 40 (12 original and 28 newly identified) Swedish families with hereditary prostate cancer (HPC) that, on the basis of 40 markers spanning a 25-cM interval within 1q24-25, have evidence of linkage. In the complete set of families, a maximum two-point LOD score of 1.10 was observed at D1S413 (at a recombination fraction [theta] of.1), with a maximum NPL (nonparametric linkage) Z score of 1.64 at D1S202 (P=.05). The evidence of linkage to this region originated almost exclusively from the subset of 12 early-onset (age <65 years) families, which yielded a maximum LOD score of 2.38 at D1S413 (straight theta=0) and an NPL Z score of 1.95 at D1S422 (P=.03). Estimates from heterogeneity tests suggest that, within Sweden, as many as 50% of early-onset families had evidence of linkage to the HPC1 region. These results are consistent with the hypothesis of linkage to HPC1 in a subset of families with prostate cancer, particularly those with an early age at diagnosis.

Apoptosis and p53 gene expression in male reproductive tissues of cadmium exposed rats

Reverse transcription (RT) PCR technique was used to investigate the mechanism of apoptosis induced by Cd and the change of its related genes in testes and prostate of rats. Adult male rats were given a single (s.c.) injection of CdCl2 0, 2.5, 5.0, 10 mumol/kg. 48 h and 72 h after administration of Cd, animals were sacrificed. The results indicated that Cd can induce apoptosis in testes via p53-independent pathway. No apoptosis occurred in prostate in any of the Cd-exposed groups. There was a clearly negative relationship in testes between p53 gene expression and Cd exposure and this dose-response relationship was observed both at 48 h and 72 h. There was a very small increase of this gene expression in the dorsolateral lobe of the prostate in Cd exposed groups. The other apoptosis related gene, bcl-x, was not detectable in either control or Cd-exposed group in testes and dorsal prostate. Although the MT-I gene was expressed in testes or dorsal prostate both in control and exposed groups, no overexpression of MT-I gene was found after administration of Cd. The expression of MT-I in the ventral prostate was not detected in the control group, but a weak expression was found after Cd exposure. Since p53 is a tumor suppressor gene which can inhibit tumorigenesis, the consequence of a Cd-induced decrease of p53 in testes may have a relation to the known risk of Cd tumorigenesis in this tissue.

Alterations of transforming growth factor beta1 (TGF-beta1) and TGFbeta receptor expressions with progression in Dunning rat prostatic adenocarcinoma sublines

Transforming growth factor-beta1 (TGF-beta1) inhibits epithelial cell proliferation in the normal prostate. Prostate tumours express high levels of TGF-beta1, and seem to acquire resistance to its anti-proliferative effects with tumour progression. In this study, TGFbeta variations with tumour progression were examined in the Dunning prostatic adenocarcinoma model. Expression of TGF-beta1 and TGFbeta receptor type I and type II (TGFbeta-RI and TGFbeta-RII) in rat dorsolateral prostate (DLP) and Dunning tumour sublines (PAP, AT-1, AT-2, AT-3 and MatLyLu) was examined in vitro and in vivo, using competitive reverse transcription-polymerase chain reaction (RT-PCR), Northern and Western blot, and immunohistochemistry. All tumours expressed elevated levels of TGF-beta1 and TGFbeta-RI mRNA, when compared with the DLP (P < or = 0.05). All tumours except MatLyLu also expressed elevated levels of TGFbeta-RII mRNA (P < or = 0.05). Interestingly, TGFbeta-RII protein levels were very low in the highly metastatic AT-3 and MatLyLu tumours in vivo, when compared with levels in the PAP, AT-1, and AT-2 tumours. This difference was not detected for the AT-1, AT-2, and AT-3 cells in vitro. Immunostaining of TGF-beta1, TGFbeta-RI, and TGFbeta-RII was localised principally in normal and tumour epithelial cells, and occasionally in smooth muscle cells. In conclusion, high expression of TGF-beta1 and TGFbeta-RI and low expression of TGFbeta-RII may contribute to tumour progression and metastasis in the Dunning prostatic adenocarcinoma model.

Transient ischemia induces apoptosis in the ventral prostate of the rat

The mechanisms involved in the castration-induced involution of the ventral prostate (VP) are not fully understood. It was recently reported that castration decreases blood flow in the VP in rats and that this occurs before the apoptotic involution of the organ. However, it is unknown whether a decrease in blood flow may trigger apoptosis in the VP, and this was therefore examined in this study. The right iliac artery was clamped for 1 h in adult male rats. After 24 h of reperfusion, the VPs were frozen or fixed. In situ end-labeling (ISEL) was used to identify apoptotic cells, and testosterone repressed prostatic message-2 (TRPM-2) was measured. Proliferating cell nuclear antigen (PCNA) immunohistochemistry was used to identify proliferating cells. Clamping the right iliac artery reduced blood flow in the right VP to 0.17 of that in the contralateral lobe. This relative ischemia resulted in a threefold increase in the volume density of apoptotic epithelial cells on the treated side, but left cell proliferation unaffected. Testosterone substitution did not change this pattern. This study suggests that a transient period of relative ischemia may induce apoptosis in the rat ventral prostate. This may be of importance for the understanding of castration-induced prostatic involution.

Expression of gonadotropin-releasing hormone receptor mRNA in the rat ventral prostate and dunning R3327 PAP adenocarcinoma before and after castration

BACKGROUND

Continuous administration of gonadotropin-releasing hormone (GnRH) agonists in prostate cancer patients results in involution of the tumors due to suppression of androgen production. In addition to the effect of GnRH at the hypothalamic-pituitary level, experiments in vitro on breast, ovary, and prostatic cells have shown an inhibition of cell proliferation, indicating the presence of local GnRH receptors (GnRH-R). The aim of the present study was to investigate the expression of GnRH-R mRNA in the normal rat ventral prostate (VP) and Dunning R3327 PAP adenocarcinoma and to evaluate the effects of castration on receptor mRNA expression.

METHODS

RNA was prepared from ovaries, pituitaries, VP, and Dunning tumors from both intact and castrated animals. GnRH-R mRNA levels were quantified by a competitive reverse transcription-polymerase chain reaction (RT-PCR) method.

RESULTS

GnRH-R mRNA was detected in normal VP and Dunning tumors. Normal VP showed lower amounts of GnRH-R mRNA compared to Dunning tumors. An elevation of mRNA expression was observed 7 days after castration in Dunning tumors.

CONCLUSIONS

GnRH-R mRNA was found in both VP and Dunning tumors, indicating the presence of a local GnRH system. Normal VP showed lower amounts of GnRH-R mRNA when compared to malignant tissues. GnRH-R mRNA levels were elevated in Dunning tumors following castration.

Testosterone induces vascular endothelial growth factor synthesis in the ventral prostate in castrated rats

PURPOSE

Recent studies suggest that the vasculature is important for the control of prostate growth. Castration induces an involution of the prostate gland and its vasculature. Replacement of testosterone stimulates endothelial cell proliferation and normalizes vascular volumes and blood flow several days before organ regrowth. Antiangiogenesis treatment inhibits the growth of prostate tumors. Understanding the regulation of the prostate vasculature may therefore provide important knowledge of the mechanisms responsible for the growth of non-malignant and malignant prostate tissue. Castration induced regression and testosterone stimulated regrowth of the prostatic vasculature have here been used to study the involvement of the angiogenic factor vascular endothelial growth factor (VEGF) and its receptors flt-1 and flk-1/KDR in the regulation of the prostatic vasculature.

MATERIALS AND METHODS

VEGF, flt-1, and flk-1/KDR levels were quantified in the rat ventral prostate following castration and testosterone replacement. Methods used were competitive RT-PCR, Western blot and immunohistochemistry.

RESULTS

VEGF mRNA and protein levels were significantly decreased by castration and testosterone treatment induced VEGF synthesis in the rat ventral prostate epithelium. Flt-1 and flk-1/KDR receptor levels were unaffected by castration and testosterone treatment.

CONCLUSIONS

Castration down regulates VEGF and testosterone induces VEGF synthesis in epithelial cells in the rat ventral prostate.

Pituitary adenylate cyclase-activating polypeptide (PACAP): effects on blood flow in the testis and caput epididymidis of the rat

Pituitary adenylate cyclase-activating polypeptide (PACAP) is synthesized in developing germ cells in the testis and may act as a paracrine modulator of spermatogenesis and/or participate in tubule-interstitial interactions. Despite the abundance of PACAP in the organ, its role in testicular function has not yet been studied in vivo. Using laser Doppler flowmetry, the effects of PACAP on blood flow in the testis and caput epididymidis were studied on anesthetized adult rats. When given intratesticularly as 5- and 50-ng doses, PACAP increased blood flow by 55+/-21% (mean +/- SEM, P < 0.05) and by 68+/-11% at 5 mm from the injection site, respectively. Whereas 5 ng PACAP did not influence blood flow 15 mm from the site of injection, flow was reduced (-7+/-3; P < 0.05) at this site following treatment with 50 ng. Injection of 50 ng PACAP into the caput epididymidis increased epididymal blood flow by 18+/-4% (P < 0.05) at 1 mm from the injection site. None of the treatments above significantly affected the mean arterial blood pressure. Using immunohistochemistry, PACAP was observed in elongated spermatids and in the acrosomes of round spermatids in some, but not all, seminiferous tubules. Also, distinct PACAP immunoreactivity was seen in epithelial cells, particularly in clear cells, of the caput epididymidis. In conclusion, PACAP can induce vasodilatation in both testicular and epididymal microvessels and may be involved in regulating blood flow in these organs. Whereas the vasodilatory effect of PACAP is strong in the testis, the epididymal response appears to be more moderate.