0022-534 7/78/1193-0623$02. 00/0 Vol. 119, May Printed in U.SA.
THE JOURNAL OF UROLOGY
Copyright © 1978 by The Williams & Wilkins Co.
ALTERED ANDROGEN METABOLISM IN METASTATIC PROSTATE CANCER B. KLIMAN,* G. R. PROUT, JR., R. A. MACLAUGHLIN, J. J. DALY
AND
P. P. GRIFFIN
From the Endocrine Unit, Department of Medicine, Urological Service and the Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts
ABSTRACT
Admixture of androgen-sensitive elements from normal ot hyperplastic prostatic tissue interferes with biochemical studies of prostate cancer in its primary site. Heterogeneity of cancer tissues, varying in stromal and epithelial elements, also complicates interpretation of data relating to androgen metabolism. Accordingly, we have compared metastatic deposits composed of epithelial cancer cells to the primary biopsies of 4 patients in respect to uptake of 3H-testosterone and its conversion to 5-a-dihydrotestosterone during in vitro incubation. 3H-testosterone uptake was similar for both tissue sites but 3H-dihydrotestosterone formation was reduced by 76 per cent in the metastases compared to primary tissues. This group was not large enough to show statistical significance, whereas a total of 11 such primary studies compared to 6 metastatic specimens was significant. When either primary or secondary tissue results were compared to 12 cases of benign prostatic hyperplasia similarly studied the differences were highly significant. These results demonstrate a major impairment in the formation of dihydrotestosterone by metastatic prostatic cancer and a similar but less evident alteration in the primary site. This abnormality in testosterone metabolism is of major importance in the attempt to obtain effective hormonal control of human prostatic cancer. The therapy of prostatic cancer is based on the hypothesis that this neoplasm is androgen dependent. Although favorable responses have been achieved with castration and estrogens, 1 and by antiandrogens2 ultimate relapse and progression are observed. 3 Basic investigations of androgen action in prostatk tissues indicate the involvement of testosterone uptakej Cohversion to dihydrotestosterone and transport of dihydrotestosterone to a nuclear site of action. 4• 5 Previously, we have confirmed testosterone uptake and conversion to dihydrotestosterone in vitro by human normal prostate and benign prostatic hyperplasia but noted more variable and less active mechanisms in tissue obtained by biopsy or prostate glands containing cancer. 6 The interpretation of such studies is complicated by varying degrees of epithelial cell differentiation, admixture with elements of non-neoplastic prostatic tissue and the finding that even stroma itself is capable of testosterone uptake and conversion to dihydrotestosterone. 6 To study more homogeneous specimens of prostatic cancer we have obtained metastatic deposits in regional lymph nodes for similar metabolic evaluations. With such specimens and sitnilarly studied biopsies of the primary lesions we have now demonstrated a major alteration in androgen metabolism, which provides a possible explanation for the resistance of prostatic cancer to hormonal control therapy.
treatment. 7 The fresh tissues were taken promptly to the laboratory and divided to provide tissue for biochemical investigation and mirror-sections for pathological study. The methodology for incubation of tissue with 3 H-testosterone, isolation of 3H-testosterone and 3H-dihydrotestosterone, and calculation or cell uptake of 3H-testosterone and its conversion to 3Hdihydtotestosterone has been described previously. 6 Additional data on the standardization of time of incubation and tracer concentration are included herein. All incubations were performed with the same conditions found to be optimal for the highly active tissues of benign prostatic hyperplasia. The radioactive 3H and 14C-labeled testosterone and dihydrotestosterone used in these studies were obtained from New England Nuclear Corporation and used within 3 months from the date of shipment. RESULTS
Timing of tissue incubation. Aliquots of benign prostatic hyperplasia were obtained from a single specimen removed by operation without use of cauterization. Twenty-five mg. portions were incubated with 0.39 pM. 3H-testosterone. The cellular contents of 3H-testosterone and 3H-dihydrotestosterone were measured at varying intervals from 1 minute to 2 hours. The results are shown in figure 1 and demonstrate optimal testosterone uptake and dihydrotestosterone producMETHODS tion at 1 hour of incubation. This time was used for all The study included men with prostatic cancer who were subsequent studies. about to receive conventional therapy. lnformed consent was Testosterone substrate concentration. A single large speciobtained to remove prostatic tissue by needle biopsy. Meta- men of benign prostatic hyperplasia was divided into 25 mg. static deposits were encountered during the standard staging aliquots and incubated for 1 hour in the presence of varying procedure in which pelvic nodes are examined before detmitive amounts of 3H-testosterone between 0.24 to 2.84 pM./100 mg. wet weight (table 1). These additions were associated with a Accepted for publication June 10, 1977. Read at annual meeting of American Urological Association, relatively linear production of3H-dihydrotestosterone and did not saturate the 5-a-reductase system (fig. 2). Since saturation Chicago, Illinois, April 24-28, 1977. Supported by grants from the United States Public Health Service conditions were not observed a tracer concentration of 1.56 CA 15944 and CA 152844 and from the Skerryvore Foundation to pM./100 mg. was chosen to provide reproducible results in George R. Prout, Jr., Chief, Urological Service, Massachusetts subsequent studies. General Hospital, Boston, Massachusetts. Confirmation of 5-a-reductase activity. To confirm that *Requests for reprints: Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114. the 3 H-dihydrotestosterone isolated was the product of the 5623
624
KLIMAN AND ASSOCIATES
B. P.H. 0.39 pM / 25 mg 30
25
THE JOURNAL OF UROLOGY
Copyright © 1978 by The Williams & Wilkins Co.
ALTERED ANDROGEN METABOLISM IN METASTATIC PROSTATE CANCER B. KLIMAN,* G. R. PROUT, JR., R. A. MACLAUGHLIN, J. J. DALY
AND
P. P. GRIFFIN
From the Endocrine Unit, Department of Medicine, Urological Service and the Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts
ABSTRACT
Admixture of androgen-sensitive elements from normal ot hyperplastic prostatic tissue interferes with biochemical studies of prostate cancer in its primary site. Heterogeneity of cancer tissues, varying in stromal and epithelial elements, also complicates interpretation of data relating to androgen metabolism. Accordingly, we have compared metastatic deposits composed of epithelial cancer cells to the primary biopsies of 4 patients in respect to uptake of 3H-testosterone and its conversion to 5-a-dihydrotestosterone during in vitro incubation. 3H-testosterone uptake was similar for both tissue sites but 3H-dihydrotestosterone formation was reduced by 76 per cent in the metastases compared to primary tissues. This group was not large enough to show statistical significance, whereas a total of 11 such primary studies compared to 6 metastatic specimens was significant. When either primary or secondary tissue results were compared to 12 cases of benign prostatic hyperplasia similarly studied the differences were highly significant. These results demonstrate a major impairment in the formation of dihydrotestosterone by metastatic prostatic cancer and a similar but less evident alteration in the primary site. This abnormality in testosterone metabolism is of major importance in the attempt to obtain effective hormonal control of human prostatic cancer. The therapy of prostatic cancer is based on the hypothesis that this neoplasm is androgen dependent. Although favorable responses have been achieved with castration and estrogens, 1 and by antiandrogens2 ultimate relapse and progression are observed. 3 Basic investigations of androgen action in prostatk tissues indicate the involvement of testosterone uptakej Cohversion to dihydrotestosterone and transport of dihydrotestosterone to a nuclear site of action. 4• 5 Previously, we have confirmed testosterone uptake and conversion to dihydrotestosterone in vitro by human normal prostate and benign prostatic hyperplasia but noted more variable and less active mechanisms in tissue obtained by biopsy or prostate glands containing cancer. 6 The interpretation of such studies is complicated by varying degrees of epithelial cell differentiation, admixture with elements of non-neoplastic prostatic tissue and the finding that even stroma itself is capable of testosterone uptake and conversion to dihydrotestosterone. 6 To study more homogeneous specimens of prostatic cancer we have obtained metastatic deposits in regional lymph nodes for similar metabolic evaluations. With such specimens and sitnilarly studied biopsies of the primary lesions we have now demonstrated a major alteration in androgen metabolism, which provides a possible explanation for the resistance of prostatic cancer to hormonal control therapy.
treatment. 7 The fresh tissues were taken promptly to the laboratory and divided to provide tissue for biochemical investigation and mirror-sections for pathological study. The methodology for incubation of tissue with 3 H-testosterone, isolation of 3H-testosterone and 3H-dihydrotestosterone, and calculation or cell uptake of 3H-testosterone and its conversion to 3Hdihydtotestosterone has been described previously. 6 Additional data on the standardization of time of incubation and tracer concentration are included herein. All incubations were performed with the same conditions found to be optimal for the highly active tissues of benign prostatic hyperplasia. The radioactive 3H and 14C-labeled testosterone and dihydrotestosterone used in these studies were obtained from New England Nuclear Corporation and used within 3 months from the date of shipment. RESULTS
Timing of tissue incubation. Aliquots of benign prostatic hyperplasia were obtained from a single specimen removed by operation without use of cauterization. Twenty-five mg. portions were incubated with 0.39 pM. 3H-testosterone. The cellular contents of 3H-testosterone and 3H-dihydrotestosterone were measured at varying intervals from 1 minute to 2 hours. The results are shown in figure 1 and demonstrate optimal testosterone uptake and dihydrotestosterone producMETHODS tion at 1 hour of incubation. This time was used for all The study included men with prostatic cancer who were subsequent studies. about to receive conventional therapy. lnformed consent was Testosterone substrate concentration. A single large speciobtained to remove prostatic tissue by needle biopsy. Meta- men of benign prostatic hyperplasia was divided into 25 mg. static deposits were encountered during the standard staging aliquots and incubated for 1 hour in the presence of varying procedure in which pelvic nodes are examined before detmitive amounts of 3H-testosterone between 0.24 to 2.84 pM./100 mg. wet weight (table 1). These additions were associated with a Accepted for publication June 10, 1977. Read at annual meeting of American Urological Association, relatively linear production of3H-dihydrotestosterone and did not saturate the 5-a-reductase system (fig. 2). Since saturation Chicago, Illinois, April 24-28, 1977. Supported by grants from the United States Public Health Service conditions were not observed a tracer concentration of 1.56 CA 15944 and CA 152844 and from the Skerryvore Foundation to pM./100 mg. was chosen to provide reproducible results in George R. Prout, Jr., Chief, Urological Service, Massachusetts subsequent studies. General Hospital, Boston, Massachusetts. Confirmation of 5-a-reductase activity. To confirm that *Requests for reprints: Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114. the 3 H-dihydrotestosterone isolated was the product of the 5623
624
KLIMAN AND ASSOCIATES
B. P.H. 0.39 pM / 25 mg 30
25
