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.     

Androgen receptor binding characteristics in the cytosol of the rat dorsolateral prostate gland and the dunning R-3327 prostatic adenocarcinoma

The incidence of prostatic cancer is highly correlated with advanced age, and it has been suggested that changes in androgen binding may be important in age-associated alterations in growth regulatory mechanisms of prostatic epithelial cells. In this study the effects of age on androgen binding characteristics in the dorsolateral prostate glands of young and aged Copenhagen rats were determined and the binding properties in the Dunning R3327/130 subline of rat prostatic adenocarcinoma were characterized. Tritium-labeled and nonlabeled methyltrienolone analogs (R1881) were used to study the binding properties of 5α-dihydrotestosterone receptor in the cytosol of tumors and prostate glands. Binding of R1881 was low but specific for the androgen receptor as shown by competition studies in which nonlabeled R1881, 5α-dihydrostestosterone, and testosterone competed successfully with ³H-R1881 for binding sites, but 17β-estradiol and low levels of progesterone did not. In Copenhagen dorsolateral prostate, Scatchard analysis suggested a single class of binding sites. In young animals (three to five months) the average binding capacity was 10.36 fmol/mg cytosol protein with a dissociation constant (K_d) of 2.28 nmol/L. The dorsolateral prostate of aged rats (11–16 months) showed no significant difference in specific binding characteristics as compared to the younger age group. Specific binding of ³H-R1881 in R3327/130 tumor was saturable with a single class of high-affinity binding sites having an average binding capacity of 64.77 fmol/mg cytosol protein and a K_d of 2.76 nmol/L. These data show that the tumor had approximately 6.5 times the number of binding sites as did the normal Copenhagen rat dorsolateral prostate gland. However, no age-related changes were detected through 11–16 months of age in the androgen binding characteristics of normal rat dorsolateral prostate gland that could be correlated with the higher concentration of androgen binding sites in the R3327/130 tumor subline.     

Murine monoclonal antibodies reactive with a variety of androgen independent Dunning rat prostate adenocarcinoma sublines also reactive with human prostate adenocarcinoma

Murine hybridoma-derived monoclonal antibody (MCA) to Dunning rat prostate adenocarcinoma R-3327HIS (androgen independent type) has been produced by fusing P3x63 Ag8-653 myeloma cells with splenocytes of BALB/c mice which were immunized with R-3327HIS tumor cell membranes. One monoclonal antibody designated MCA-R1 (IgG2a subtype) produced an intense immunostaining of various androgen independent Dunning rat prostate tumor sublines (HIS, HIM, HIF, AT-1, AT-2, AT-3, MAT-Lu and MAY-Ly-Lu), but did not stain other tumors of rat origin or normal rat tissues. Marginal immunostaining was detected in the androgen responsive R-3327H and R-3327G tumor subline. Although MCA-R1 antibody did not react with the regressed prostate tumor of R-3327H or R-3327G, it strongly reacted with the relapsed prostate tumor from either R-3327H or R-3327G tumor derived from rats were treated with diethyl stilbestrol (DES) or castration. MCA-R1 antibody also produced a strong cross-reaction with human prostate adenocarcinoma. Like the Dunning rat tumor, human adenocarcinoma exhibited distinct immunostaining patterns with respect to intracellular localization among well differentiated, moderately differentiated and poorly differentiated tumor. Benign prostatic hyperplasia or other normal tissues did not stain. Immunofluorescence, immunoprecipitation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and radioautographic analysis revealed that the Dunning rat prostate tumor antigen recognized (m.wt. 50 and 120 Kd) by MCA-R1 antibody are localized on both cell surface and in the cytoplasm. This MCA may represent a potential reagent for the study of tumor biology and immunotherapy of prostate tumor.     

Expression of ras proto-oncogenes in the Dunning R3327 rat prostatic adenocarcinoma system

Steady-state levels of c-Ha-ras mRNA were measured in eight sublines of the Dunning R3327 rat prostatic adenocarcinoma. As a control, normal dorsal prostate tissue was studied. Increased expression of c-Ha-ras is associated with tumor progression in one lineage of the Dunning R3327 system (H to AT1 to MAT-Lu and MAT-Ly-Lu). Here ras mRNA increases as the tumor advances from androgen dependence and a high degree of differentiation to an anaplastic aneuploid phenotype with high metastatic potential. However, in the other Dunning lineage (H to HI to HI-F to AT3), expression of c-Ha-ras is variable and does not correlate with tumor progression. Immunocytochemistry showed that levels of the c-Ha-ras p21 protein paralleled steady-state mRNA levels in variants. Transfection assays, using NIH/3T3 cells, suggested that the ras loci were not activated in the R3327 tumors. Levels of c-Ki-ras mRNA were also measured in the Dunning tumors; these did not correlate with tumor progression in either lineage. Expression of N-ras mRNA was not detected in the Dunning tumors.     

Role of prolactin in modulating the effects of tamoxifen on growth of the Dunning R3327 rat prostate adenocarcinoma

Tamoxifen (TAM) has previously been shown to inhibit growth of the Dunning R3327 rat prostate adenocarcinoma and to elevate serum prolactin levels. The purpose of this study was to determine the role of prolactin in modulating the effects of tamoxifen on growth of the R3327 prostatic adenocarcinoma. Intact and castrated Copenhagen-Fischer male rats bearing the Dunning R3327 rat prostatic tumor were divided into groups and injected sc five times per week for 16 weeks as follows: vehicle; TAM (0.5 mg/kg); haloperidol (HALO; 0.5 mg/kg); bromocriptine (CB-154; 5 mg/kg); TAM plus HALO; or TAM plus CB-154. In both intact and castrated rats, agents that either raised (HALO) or lowered (CB-154) serum prolactin had little effect on prostatic tumor growth when administered singly. In intact rats, average tumor diameter in vehicle-treated controls increased 421% 16 weeks after the start of the experiment, and treatment with TAM or TAM plus HALO reduced this tumor growth by approximately one-half. Interestingly, CB-154 administered in combination with TAM completely blocked TAM inhibition of tumor growth in intact rats. In contrast to these results in intact rats, average tumor diameter increased 129% in TAM- and 118% in TAM plus HALO-treated castrated rats and was significantly greater than the characteristic retardation of tumor growth (49% increase) that occurred in the vehicle-treated castrate controls. In addition, combined treatment of TAM plus CB-154 in castrate rats resulted in an even greater increase (188%) in average tumor diameter. The inhibitory effect of TAM on R3327 prostatic tumor growth in intact rats appears to be an indirect effect resulting from its ability to reduce serum testosterone levels. In contrast, the stimulatory effect of TAM in castrate rats appears to result directly from an estrogen-like action, which can directly enhance prostatic tumor growth in the presence of low levels of circulating androgens; this stimulatory effect of TAM is more pronounced when prolactin levels are suppressed by CB-154. Clearly, castration alone is more effective than TAM therapy alone or in combination with castration in the retardation of the growth of the androgen-dependent R3327 prostatic tumor in rats.     

Leukocytic subset distributions of spleen cells obtained from rats bearing variants of the Dunning prostatic adenocarcinoma

Employing monoclonal antibodies, the relative frequencies of mononuclear cell types found in spleen cell populations were compared between rats bearing variants of the Dunning prostate adenocarcinoma and a series of non-tumor bearing control animals. The identification and quantitation of such subsets greatly expands our knowledge of immune status and function. The results indicate that the spleen cell populations from animals bearing either the Dunning R3327-H, G or MAT-LyLu sublines have significant decreases in their helper T cell/suppressor T cell ratios when comparisons are made to cells obtained from non-tumor bearing animals. In addition decreases in total T cell content and increases in splenic monocytes were noted. It appears that most of these deviations are the result of general Dunning tumor presence, rather than due to any particular subline characteristic. These changes may be analogous to similar alterations reported in the peripheral blood of humans bearing Stage D prostatic cancer, suggesting that the Dunning tumor may provide an appropriate model for evaluating interactions between the immune response, the tumor and therapy.     

Copenhagen rat prostatic tumor ornithine decarboxylase activity (ODC) and the effect of the ODC inhibitor alpha-difluoromethylornithine

The R3327MAT-Lu tumor is a rapidly growing anaplastic derivative of the Dunning R3327 prostatic adenocarcinoma. We have found the ornithine decarboxylase (ODC) activity of this tumor to be as sensitive to inhibition by alpha-difluoromethylornithine (DFMO) as normal rat prostate. The same was true for all the other R3327 tumor derivatives we studied. The in vivo inhibition of ODC by DFMO allowed increased uptake of exogenously administered putrescine by the R3327 AT tumor. Further, DFMO was inhibitory to the growth of the R3327MAT-Lu both in vitro and in vivo.     

Stability of sublines in the R3327-H rat prostatic tumor

Over several years of in vivo maintenance passage the R3327-H rat prostatic tumor has given rise to nine unique sublines in our laboratory. Some have emerged under selective treatment pressure while others apparently represent spontaneous or random modulation. Each new subline embodied an altered histology, growth rate, metastatic pattern or treatment sensitivity in comparison to its parent subline. However, each has been subsequently passaged enough times to provide evidence of considerable phenotypic stability, a notable point in view of the R3327 tumor's well known potential for modulation.     

Characterization of muscarinic cholinergic receptors in membrane preparations from rat prostatic adenocarcinoma

The binding characteristics of 3H-quinuclidinyl benzilate (QNB) to muscarinic sites in isolated plasma membrane fractions from R-3327 Dunning tumors (H and AT-1 sublines); ventral, dorsolateral prostate; and urinary bladder of the rat were studied. QNB binding to all preparations, except from AT-1 tumors, was specific, saturable, and of high affinity. The AT-1 tumors completely lacked specific QNB binding. The muscarinic receptor density in H tumors was twofold and twentyfold higher than that in the ventral prostate and dorsolateral prostate respectively. The receptor density in the urinary bladder was approximately twofold higher than that in H tumors. The Kd values in H tumors and ventral prostate were very similar and significantly higher than that in dorsolateral prostate or the urinary bladder. QNB binding in H tumors was strongly inhibited by classical muscarinic receptor antagonists atropine and scopolamine, but poorly by the agonists carbacholine and pilocarpine. In contrast to scopolamine or atropine, inhibition by pirenzepine and AF-DX116 was relatively low. These data indicate that the muscarinic receptor in Dunning H tumors is of M3 type.     

Decrement of blood flow precedes the involution of the ventral prostate in the rat after castration

Blood flow to the rat ventral prostate (VP), dorsolateral prostate (DP), and Dunning R3327 prostatic tumors was measured at different times up to 7 days after castration, using the microsphere method. In the VP organ weight was decreased from day 3 onwards. Blood flow was, however, already significantly decreased from day 1. The reduced blood flow in VP in 1–3 and 7-day castrated animals could be reversed by testosterone treatment. Organ weight was slightly decreased but blood flow was unaffected by castration in DP. Castration left Dunning tumor volume and blood flow unaffected. Using immunohistochemistry, androgen receptors were observed in epithelial and stromal cells in VP, DP and Dunning tumors, but not in blood vessels. Castration is known to induce apoptosis in the VP, but not in the DP or in Dunning tumors. This suggests that a reduction in blood flow might be an important component for the castration-induced involution and apoptosis in prostatic tissue. The reason why castration reduces blood flow only in the VP, and not in the DP or Dunning tumor is unknown.     

Establishment and characterization of seven Dunning rat prostatic cancer cell lines and their use in developing methods for predicting metastatic abilities of prostatic cancers

In vitro cell lines were established from seven biologically distinct in vivo Dunning R3327 rat prostatic tumor sublines. Some of these in vitro cell lines (i.e., G, AT-1, AT-2) retain a low metastatic ability when inoculated back into syngeneic Copenhagen male rats, while others (i.e., AT-3, MAT-LyLu, MAT-Lu) retain a very high metastatic ability. A series of genetic (i.e., DNA content per cell, modal chromosomal number), as well as phenotypic parameters (i.e., morphology, 5 alpha-reductase, androgen receptor, estrogen receptor) were used to validate that the in vitro cell lines retained the major characteristics of the parental in vivo tumor sublines used for their respective establishment. A series of additional characteristics (i.e., morphology, growth rate, saturation density in surface culture, anchorage-dependent and -independent clonogenic potential) were compared between the high vs. the low metastatic in vitro cell lines to determine if a discriminatory parameter could be identified which reproducibly predicted the metastatic abilities of the particular prostatic cancer cell line. While the combination of the in vitro cell lines and their parental in vivo tumor subline will be a valuable tool for developing methods for predicting metastatic ability of prostate cancers, no single parameter yet measured is entirely successful in making this important distinction.     

Acid phosphatase-producing androgen-independent subline of rat prostatic adenocarcinoma (Dunning R3327 tumor) in cell culture

Establishment of a cell line derived from the androgen-independent subline of rat prostatic adenocarcinoma (Dunning R3327 tumor) is reported. Cells of this line produced acid phosphatase. When the cultured cells were transplanted to Copenhagen rats, solid tumors were formed. Histologically, the tumor consisted of spindle-shaped, large and bizarre polygonal cells; this feature was almost identical to that of the original tumor. Chromosomes were in the triploid range with seven frequently appearing marker chromosomes.     

Growth hormone receptor expression in the Dunning R 3327 prostatic carcinoma of the rat.

The Dunning R3327 rat carcinoma is an important model for human prostate adenocarcinoma. In the present study this tumor was further characterized by immunohistochemical demonstration of receptors for growth hormone (GH-R). Weak GH-R immunoreactivity was present in the secretory epithelial cells of the tumor acini. Large epithelial cells which were localized at the periphery of the acini and large cells in the stroma, which are probably derived from the epithelium ("Large neoplastic epithelial cells"), displayed a strong staining with one of the monoclonal antibodies (Mab 263) to GH-R. The presence of GH-R receptors in proliferating prostatic tumor cells supports the concept that GH reacts directly on prostate target tissue to facilitate tumor cell growth.     

Differences in expression of oligosaccharide determinants by phenotypically distinct sublines of the Dunning 3327 rat prostate cancer

Oligosaccharides expressed by the 3327-H and 3327-MAT LyLu sublines of the Dunning rat prostate cancer model have been compared in formalin-fixed and routinely paraffin-embedded tumour tissues. Binding by lectins of defined specificity has been employed to identify expression of seven oligosaccharide structures by primary and metastatic prostatic carcinoma cells. Neuraminidase digestion was employed to reveal determinants masked by sialic acid. The presence of core Man alpha 1----3(Man alpha 1----6)Man beta 1----4GlcNAc beta 1----4 determinants recognised by Con-A (Canavalia ensiformis) confirmed expression of complex-type glycoconjugates by plasma membrane and cytoplasmic components of the 3327-H tumour but only by cytoplasmic determinants within 3327 MAT LyLu variant tumour-cells. The only other oligosaccharide freely expressed by either tumour-subline was (GlcNAc beta 1----4GlcNAc beta 1----4-)n, recognised by WGA (Triticum vulgaris). Prior to neuraminidase digestion, PNA (Arachis hypogaea) (which identifies Type I oligosaccharides: Gal beta 1----3GalNAc-) bound to pseudoluminal membranes of the 3327-H tumour. However, ECG (Erythrina cristagalli) (which identifies type II oligosaccharides: Gal beta 1----4GlcNAc-) did not bind to this tumour. Unmasked Type I (Gal beta 1----3GalNAc-) and Type II (Gal beta 1----4GlcNAc-) oligosaccharides were not identified in the MAT-LyLu variant. After neuraminidase digestion, PNA-binding was identified along pseudoluminal plasma membranes within 3327-H tumours but only within the cytoplasm of 3327-MAT LyLu primary and metastatic tumour cells. Following neuraminidase digestion, ECG-binding was observed along pseudoluminal plasma membranes of 3327-H tumours and heterogeneously within the cytoplasm of primary, but not metastatic 3327-MAT LyLu tumours. Terminal alpha/beta GalNAc- residues recognised by SBA (Glycine max) were not freely expressed by either subline. These structures were readily detected along luminal membranes of 3327-H cells and weakly detected within the cytoplasm of primary but not metastatic MAT 3327-LyLu tumour cells following neuraminidase digestion. Fucosylated Type II structures Fuc alpha 1----2Gal(GalNAc)-), recognised by UEA-1 (Ulex europaeus-1) and GalNAc alpha 1----3GalNAc- structures recognised by DBF (Dolichos biflorus) were not identified as a component of either tumour subline. The different patterns of oligosaccharide expression, identified by lectin-binding, clearly differentiated between the two tumour sublines and distinguished them from normal prostatic epithelium. The Dunning 3327 rat prostatic cancer sublines offer a useful model with which to examine the relationship between cell-surface oligosaccharide structures and phenotypic variants within a defined tumour-cell population.(ABSTRACT TRUNCATED AT 400 WORDS)     

Response of rat and human prostatic cancers to the novel 5 alpha-reductase inhibitor, SK&F 105657.

The response of two androgen-responsive rat prostatic cancers (i.e., Dunning R-3327 H and G sublines) and one androgen-responsive human prostatic cancer (i.e., PC-82) to the 5 alpha-reductase inhibitor, SK&F 105657, was tested in vivo. SK&F 105657 was administered orally twice a day at a dose of 25 or 50 mg/kg/dose. The rat R-3327 G tumor and the human PC-82 tumor have a low to undetectable level of tissue 5 alpha-reductase activity and both responded to SK&F 105657 treatment with a reproducible inhibition of tumor growth. Associated with this antitumor effect was a major decrease (i.e., greater than 70%) in tissue dihydrotestosterone (DHT) content in both tumors. By contrast, the rat R-3327 H prostatic cancer has a much higher level of tissue 5 alpha-reductase activity, and neither tumor DHT content nor growth of the tumor was inhibited by treatment with SK&F 105657. Drug treatment of rats bearing R-3227 H tumors resulted in a similar reduction in the DHT content, wet weight, and DNA content of the ventral prostate as that produced in R-3327 G tumor-bearing rats which experienced an antitumor response. These results suggest that SK&F 105657 can produce antitumor effects if a substantial reduction in tissue DHT is achieved. Such reduction in tissue DHT, secondary to inhibition of the tissue 5 alpha-reductase enzyme, appears to be more difficult to achieve in tumors than in the normal prostate. In order to achieve such a DHT reduction in tumor tissue, prostatic cancers with low 5 alpha-reductase activity could be treated with SK&F 105657 on a dose regimen that lowers serum DHT to surgical castration levels, while concomitantly inhibiting the already low tumor tissue 5 alpha-reductase activity.     

Receptors for luteinizing hormone-releasing hormone, somatostatin, prolactin, and epidermal growth factor in rat and human prostate cancers and in benign prostate hyperplasia

Using sensitive multipoint micromethods, we estimated membrane receptors for [D-Trp6]-luteinizing hormone-releasing hormone ([ D-Trp6]-LH-RH), somatostatin (SS-14), human prolactin (hPRL), and epidermal growth factor (EGF) in experimental Dunning rat prostate cancers and in samples of normal human prostate, benign prostatic hyperplasia (BPH), and human prostate cancer (PC) obtained from biopsy, after prostatectomy, or at autopsy. In the Dunning R-3327 rat prostate adenocarcinoma specimens, the receptors were characterized in untreated animals and following in vivo treatment with microcapsules of the agonist [D-Trp6]-LH-RH and the somatostatin analog RC-160. Two populations of binding sites were found for [D-Trp6]-LH-RH, one with high affinity and low capacity and another with low affinity and high capacity. Treatment with [D-Trp6]-LH-RH and RC-160 alone or with the combination of these analogs increased the binding capacity (Bmax) of the low-affinity binding sites for [D-Trp6]-LH-RH and decreased Bmax for hPRL and EGF. Therapy with [D-Trp6]-LH-RH also reduced Bmax of SS-14 binding and dissociation binding constant of high-affinity binding sites for [D-Trp6]-LH-RH, whereas administration of RC-160 or the combination treatment with both analogs increased Bmax of SS-14 binding. These findings are compatible with the view that analogs of LH-RH and SS-14 might exert some direct inhibitory effects on the Dunning prostate cancer. Among 13 human BPH samples examined, only one had receptors for [D-Trp6]-LH-RH, and seven specimens exhibited binding for prolactin. [D-Trp6]-LH-RH receptors were found in all seven samples of human PC but not in any of the eight specimens of normal human prostate. All samples of normal human prostate, BPH, and human PC exhibited binding sites for EGF but not for SS-14. Our findings on the membrane receptors in the human and rat prostate cancers raise the intriguing possibility that LH-RH, acting as a growth factor, along with EGF and prolactin, might be involved in complex interactions that contribute to the promotion of prostate cancer in man.     

Time lapse videomicroscopic identification of Dunning R-3327 adenocarcinoma and normal rat prostate cells

A method for accurate prediction of prognosis in human prostatic cancer does not exist. The limitations of pathologic grading systems may result from the failure of standard pathological examination of fixed dead tissue to accurately assess the biological behavior of live tumor cells. Many of the sublines of the Dunning R-3327 rat adenocarcinoma are histologically similar yet differ widely in their metastatic potential. The nonmetastatic G, occasionally metastatic AT-1 and AT-2, and highly metastatic AT-3 and MAT-Lu Dunning sublines, and normal dorsal prostate were grown in culture and filmed by time-lapse videomicroscopy. Cell membrane ruffling, undulation and pseudopodal extension, vectoral translation, irregularity of pathway, and overall subjective motility (gestalt) were visually graded. Intra-assay, intra-observer, and inter-observer reproducibility were 75, 80 and 75% respectively. The combination of ruffling, pseudopodal extension and vectoral translation was most successful in identifying the six sublines. To validate this technique prospectively, five tumor sublines and two normal prostates were graded by 10 observers unfamiliar with the technique. Fifty-nine percent of unknowns were correctly identified when motility profiles were compared to previously developed standards by least sum of squares analysis. We devised a new technique for characterizing the motility of living prostate cells which was more accurate in identifying normal rat prostate and the Dunning sublines than standard pathological examination. Prostatic cancer cell motility may reflect biological behavior and metastatic potential and thus contribute to the assessment of an individual patient's prognosis.     

Autoradiographic localization of estrogen and androgen target cells in human and rat prostate carcinoma

The distribution of estrogen target cells within the Dunning R3327-H rat prostate tumor following intravenous injection of tritiated estradiol into rat hosts was compared to the distribution obtained following incubation of a 2 mm. sample of the tumor with tritiated estradiol in organ culture. No difference was observed, indicating that the in vitro method was an effective approach for autoradiographic analysis of tumor biopsy samples. Subsequently, tumor samples were excised from solid tumors of R3327-H and R3327-MAT LyLu tumors growing in Copenhagen rats. These tumor models were chosen as representatives of hormone sensitive (R3327-H) and hormone insensitive (R3327-MAT LyLu) tumors. Normal rat dorsal prostate and human tumor biopsy samples were also studied. Autoradiographic studies were performed in vitro utilizing tritiated estradiol and tritiated dihydrotestosterone to compare the distribution of estrogen and androgen target cells. The present research demonstrated that 1) similar patterns of nuclear uptake of steroids are obtained with in vivo and in vitro autoradiographic techniques, 2) estradiol receptors occur primarily in extra-acinar epitheloid cells in both rat and human prostate carcinomas, 3) these epithelioid cells are not characteristic of the normal rat dorsal prostate, 4) androgen receptors occur in both acinar and stromal epithelioid cells in rat and primarily in acinar epithelial cells in human tumors and 5) in vitro autoradiographic methods can provide insight into differences in sensitivity to steroids which may be of diagnostic importance in the treatment of cancer.     

alpha-Difluoromethylornithine enhancement of 14C-putrescine uptake by an androgen-dependent prostatic tumor

Putrescine is a potential scanning agent for metastases of prostatic carcinoma. We examined the in vivo uptake of [14C]-putrescine by the Dunning R3327H Copenhagen rat prostatic tumor and by other tissues, and conclude that: The uptake of [14C]-putrescine by the tumor was higher than that of the normal dorsolateral prostate, but similar to that of the ventral prostate. Tumor accumulation of [14C]-putrescine was enhanced 38% in intact and 45% in castrated animals by pretreatment with alpha-difluoromethylornithine (DFMO), a polyamine synthesis inhibitor. Further enhancement of tumor uptake (94% in intact and 201% in castrated animals) was achieved by combining DFMO pretreatment with androgen stimulation. Oral administration of methyl-glyoxal bis (guanylhydrazone) (MGBG) increased intestinal uptake of [14C]-putrescine, while oral administration of unlabeled spermine and putrescine decreased it. Dexamethasone decreased the uptake of [14C]-putrescine by the spleen and intestine, but also reduced the prostatic uptake to a considerable extent. These observations are useful for the design of a putrescine-based scan for metastases of prostatic carcinoma.     

Expression of endogenous receptors for neoglycoproteins in Dunning R3327 rat prostatic carcinoma

An important animal model for human prostatic adenocarcinoma is the Dunning R3327 rat carcinoma. In the present study this tumor was further characterized by analyzing the expression of endogenous sugar-binding proteins using glycohistochemistry and immunocytochemistry as well as affinity chromatography and gel electrophoresis. Our glycohistochemical and glycobiochemical results provide evidence for the presence of specific receptors for various carbohydrate moieties. Remarkably, basal cells of the Dunning tumor contain an endogenous lectin with specificity for beta-galactosides that is not found in basal cells of the normal rat prostate. This finding was corroborated using polyclonal antibodies against an immunologically related beta-galactoside-specific lectin from bovine heart. Basal cells of prostatic carcinoma may therefore behave different from normal basal cells. This difference could have a significant impact on the development of prostatic cancer.