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The Dunning R3327H rat prostatic adenocarcinoma appears to be an appropriate animal model for studying prostatic cancer. This report contains a detailed characterization of this tumor at the morphologic, biochemical, and therapeutic levels. Electron micrographic, histologic, and histochemical studies clearly establish the adenocarcinoma nature of this tumor. The histology of the R3327H tumor is similar to well-differentiated human prostatic cancer. The biochemical and enzymatic profile of the tumor indicates its origin from the rat dorsolateral prostate. The cell kinetics and growth rates of this tumor following a variety of hormonal manipulations (castration, estrogens, androgens, and antiandrogens) have established that 70%-90% of the cells in this tumor require androgens for their growth. However, 10%-30% of the cells are capable of growth in the absence of androgens. Both cell types are present in the initial tumor inoculum and these different cell types possess similar growth rates. The predominance of the androgen-sensitive cells accounts for the relatively greater size of the tumor achieved in the intact male animal at a given growth time. After the tumor is well established in an intact animal, subsequent estrogen therapy or castration resulted in a marked diminution in tumro volume. This was followed by a subsequent relapse. In addition, estramustine phosphate was also shown to cause shrinkage in the tumor volume.

The R3327 MAT-Ly Lu is a prostate derived, anaplastic, hormone independent carcinoma. It spreads primarily to regional lymph nodes, followed by lung metastases. Combination therapy with surgery (tumor removal with or without regional lymphadenectomy) and chemotherapy (ICRF-159) was more effective treatment than either one alone. Primary tumor excision plus lymphadenectomy appeared to reduce the number of pulmonary metastases.

We examined the incidence of prostatic cancer in patients with an elevated radioimmunoassay for prostatic acid phosphatase and clinical benign prostatic hyperplasia on digital rectal examination. Of 295 patients screened with prostatic acid phosphatase tests 17 fulfilled the criteria of having an elevated prostatic acid phosphatase, clinically benign prostate and histological examination of the prostatectomy specimen. None of the 17 patients had histological evidence of prostatic cancer. The results confirm the predictions of mathematical models that prostatic acid phosphatase is of no practical value as a screening test for prostatic cancer in patients with clinical benign prostatic hyperplasia.

Radiolabeled putrescine is a potential imaging agent for carcinoma of the prostate. The intrinsically high uptake of putrescine into the rat prostate and prostatic carcinoma can be further stimulated by pretreatment of the animals with alpha-difluoromethylornithine (DFMO) uptake, a polyamine synthesis inhibitor. Pharmacological castration of the animals followed by androgen stimulation and DFMO pretreatment achieved a 30:1 prostate/muscle ratio of 14C-putrescine uptake in elderly rats.

In testing for any carcinogenic effect of certain hormones the choice of test strain or strains is extremely important. By selecting several inbred strains one obtains maximum genetic variability offering a greater chance of demonstrating carcinogenesis in regard to a number of organs or tissues. The five strains of mice chosen in this study (C3H/He, C3HfB/He, BALB/cHe, A/He, and C5BL/He) provided a test for effect of Enovid at sterilizing doses on occurrence of mammary tumors, ovarian tumors, hepatomas, cervical and vaginal tumors, adrenocortical adenomas, and hypophyseal tumors. Results indicated a slight inhibitor effect of Enovid on mammary tumors in C3H and adrenocortical adenomas in BALB/c and an even greater inhibiotry effect on hepatomas in C3HfB. No effect on ovarian tumors could be detected in the appropriate test provided by C3HfB. In BALB/c females epithelial lesions of the cervix and vagina were observed in both the treated females and the controls with a slight increase in the group treated with the highest dose. All were small lesions observed only in the histologic section. None had invaded beyond the wall of the vagina, and none had metastasized. None could be classified as a frank carcinoma. In the group treated with the highest dose of Enovid, the lesions showed slightly further progression than in the other groups. The most significant tumorigenic effect of the Enovid was the increase in hypophyseal tumors in the C5BL females at advanced age. Direct extrapolation from one strain to another, from one species to another, from mouse to humans, or from one human being to another would be risky because of genetic differences. Approaches to the problem in human beings are, however, suggested. Because of these observations in mice, it would be well, if possible, to collect hypophyses of women at postmortem who have previously been on birth control pills for some time and send these hypophyses to some central laboratory where they can be examined for any changes that might be attributed to the use of the antifertility drug.

In studies with the hormone independent R3327-At prostatic tumor, relatively high doses of estrogen were inhibitory to the growth of the R3327-At rat prostatic tumor were observed. It was further observed that although tumor growth was inhibited, an increase in the [3H]thymidine labelling of the DNA of the tumor cells of the estrogen treated group relative to the castrate control was apparent.

The pH of normal human expressed prostatic secretion in 136 samples from 93 men was 7.28 +/- 0.04. In 41 samples from 14 patients with documented chronic bacterial prostatitis the alkalinity of prostatic fluid was increased 10-fold (1 pH unit) and was 8.32 +/- 0.07. We believe these studies account for the failure of trimethoprim to eradicate human bacterial prostatitis effectively despite the experimental data documenting diffusion and concentration of trimethoprim in the acidic prostatic fluid of the normal dog. The factors governing drug diffusion into the prostate and the influence of pH on the concentration of trimethoprim in the expressed prostatic secretion are discussed.

In vivo and in vitro experimentation with high energy shock waves (HESW) is necessary to further our understanding of the biologic effects and potential application of this novel energy form. Factors are identified which are critical to the design and subsequent interpretation of HESW experimentation. First, the nature of the containment vessel and the presence or absence of acoustic interfaces are shown to significantly alter the outcome of cell suspension experiments. Second, the effects of HESW are shown to differ markedly for cells in suspension versus cells in tissue making comparisons between the two uncertain. Finally, the need for appropriate negative controls is demonstrated with in vivo experiments to control for the generalized toxicity which occurs when small animals are exposed to such an intense force distributed over a relatively large area. These findings affect the interpretation of previously reported work which investigated the cytotoxic potential of HESW.

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.

The effects of human recombinant interferon-alpha 2 (IFN-alpha 2) and alpha-difluoromethylornithine (DFMO) as single agents and in combination were studied for efficacy against the renal cell adenocarcinoma (JDF-1) in an in vitro clonogenic assay and in vivo as xenografts in nude mice. In vitro studies showed dose-dependent inhibition of JDF-1 colony formation by IFN-alpha 2. DFMO alone did not significantly inhibit colony formation even though ornithine decarboxylase activity was significantly inhibited. The combination of IFN-alpha 2 and DFMO synergistically inhibited JDF-1 colony formation. The synergism was more readily observed at low IFN-alpha 2 concentrations. In vivo studies showed a similar tumor growth inhibition pattern. JDF-1 tumors were implanted s.c. in nude mice, and drugs were administered continuously by Alza minipumps (IFN-alpha 2) and in drinking water (DFMO) for 28 days. IFN-alpha 2 alone significantly inhibited JDF-1 growth, while DFMO alone had no significant inhibitory effect. The combination of IFN-alpha 2 and DFMO inhibited tumor growth in an apparent additive manner at the doses used. This was reflected in the mean tumor weights obtained at the termination of the experiment: control, 1484 +/- 187 (S.E.) mg; DFMO only, 1106 +/- 129 mg; IFN-alpha 2 only, 941 +/- 186 mg; and DFMO plus IFN-alpha 2, 620 +/- 109 mg. Assessment of mouse natural killer cell activity at the time of sacrifice showed that DFMO inhibited natural killer cell activity, while IFN-alpha 2 had no effect. DFMO was observed to inhibit ornithine decarboxylase activity in JDF-1 tumors by 78%, IFN-alpha 2 by 18%, and the combination by 78%. In addition, the drugs individually and in combination had similar inhibitory effects on JDF-1 spermidine content. One of the unexpected findings was the alteration in the spermine:spermidine ratio in the tumors treated with the combination of DFMO and IFN-alpha 2. The ratio in this group decreased to 0.44, while ratios for control, IFN-alpha 2 only, and DFMO only were 0.99, 0.66, and 0.88, respectively. These results clearly show that combined therapy with DFMO and IFN-alpha 2 is more effective than is single-drug therapy. The mechanism by which these drugs coordinately inhibit tumor growth is unclear but appears to be associated with direct inhibition of tumor cell proliferation, possibly by modulation of polyamine metabolism.

Sucrose density gradient analysis of the R3327H tumor cytosol demonstrated the presence of both androgen and estrogen binding proteins. Competitive binding analysis with 17 beta-estradiol, 5 alpha-dihydrotestosterone, R1881, cyproterone acetate, and cortisol was consistent with the presence of 2 different binding sites for androgens and estrogens. Scatchard binding analysis was performed in the dorsal-lateral prostate as well as the R3327H tumor from normal Copenhagen rats. High affinity receptors for androgen and estrogen but not progesterone were found. However, in R3327H tumors relapsing following castration, the presence of high affinity receptors for progesterone were readily detectable.

Strain A females were milked and their milk was tested for mammary tumor virus (MTV) by the hyperplastic alveolar nodule test and for MTV antigen by microimmunodiffusion. An attempt was made to correlate these results with later occurrence of mammary tumors in the females. There was not full agreement between the results of the test for the presence of the MTV and those of the test for MTV antigen, and from these results it was impossible to predict accurately whether a specific female would later develop a tumor. It is concluded that, in this strain, factors other than the MTV can be the determinant in whether the individual female will develop a tumor.

Mammary tumorigenesis in C3H-A(vy)fB female mice is not due to milk-borne mammary tumor virus but to factors transmitted at conception. Prominent among these is the A(vy) gene which may increase the virulence or transmissibility of a variant of mammary tumor virus vertically transmitted by either parent, or may increase the tumorigenic response of the mammary tissue. These factors together with the influence of hormones of pregnancy resulted in the high incidence observed.