Steroid receptors in renal cell carcinoma: relevance to hormonal therapy

Levels of urinary inter-alpha-trypsin inhibitor trimer as a function of age and sex-hormone status in males and females not forming stones

OBJECTIVES

To determine if levels of inter-alpha-trypsin inhibitor (I alpha TI)-trimer differ in normal individuals based on age, gender or hormonal status, as the regulation of calcium oxalate (CaOx) crystallization inhibitors, e.g. by sex steroids, could be a mechanism contributing to the differences in CaOx urolithiasis between the sexes.

SUBJECTS AND METHODS

Voided urine samples were collected from normal males and females. In Experiment 1 samples were grouped by gender and age, i.e. paediatric (PED) < or = 10 years, male (M) 21, female (F) 14; young adult (YGAD) 20-30 years, M 23, F 18; adults (AD), 35-50 year, M 25, F 13; adults aged > or = 60 years (> 60), M 24, F 16 (totals, M 93, F 61). In Experiment 2 samples were grouped by gender, age and hormonal status, i.e. PED, M 24, F 17; AD, M 24, F 22; > 60 and not on hormonal therapy, M 23, F 30; M > 60 and on androgen deprivation therapy (ANDEP) 18; and F > 60 on oestrogen supplementation, F+EST, 18 (total M 89, F 85). Levels of urinary I alpha TI-trimer were determined by immunoblotting and enhanced chemiluminescence, and relative densities of the bands determined.

RESULTS

In both experiments the relative levels of I alpha TI-trimer were 2-7 times higher in M-PED than in all other groups of males (P < or = 0.007). Among adult males, I alpha TI-trimer levels were similar in all groups, including ANDEP (P > or = 0.9). There were no differences in the relative levels of I alpha TI-trimer among any of the groups of females, regardless of age or hormonal status (P > or = 0.7).

CONCLUSIONS

In males a decrease in I alpha TI-trimer was associated with the onset of adulthood and entry into the 'stone-forming years'. Females did not show this decrease, and neither sex showed an increase in I alpha TI-trimer in the > 60 group, when the incidence of CaOx urolithiasis is supposedly declining. While changes in urinary I alpha TI-trimer levels in males may reflect maturational changes in the kidney, overall these data do not support the hypothesis that the age-related changes in the incidence of urolithiasis are paralleled by changes in the expression I alpha TI-trimer. Additionally, the sex steroids do not appear to acutely regulate the expression of I alpha TI-trimer in adults, making differences in I alpha TI-trimer levels unlikely to be the reason for the disparity in the incidence of CaOx urolithiasis between the sexes.

Expression of proteins that inhibit calcium oxalate crystallization in vitro in the urine of normal and stone-forming individuals

The factors precipitating clinically active calcium oxalate (CaOx) urolithiasis are not known. This study examined the relationships between urinary proteins that inhibit CaOx crystallization in vitro and the incidence of CaOx urolithiasis. The first hypothesis is that levels of urinary CaOx crystallization inhibitors differ between clinically active stone formers (SFs) and normal individuals. The second hypothesis is that lower levels of urinary CaOx crystallization inhibitors contribute to the two- to threefold greater incidence of CaOx urolithiasis in males compared with females. These hypotheses were derived from previous observations on the expression of urinary inter-alpha-trypsin inhibitor trimer (IalphaTI-trimer) in normal and stone-forming individuals. The proteins of void urine samples from normal volunteers (24 males, 19 females) and CaOx-SFs (26 males, 16 females) were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunoreactive IalphaTI-trimer, osteopontin, and prothrombin were detected by immunoblot plus enhanced chemiluminescence; the relative densities of the bands were then determined. With the exception of IalphaTI-trimer (P: </= 0.026, approximately twofold), there was no difference in the relative densities of CaOx crystallization inhibitors in the urine of normal and CaOx stone-forming individuals. Thus, there does not appear to be a generalized increase or decrease in levels of CaOx crystallization inhibitory proteins between normal and CaOx stone-forming individuals. The relative density of IalphaTI-trimer was approximately threefold greater in females than in males (P: </= 0.001). Differences in the relative densities of the other CaOx crystallization inhibitors were small and of questionable physiological importance. These data do not support the hypothesis that males have a greater incidence of CaOx urolithiasis because of a generalized decrease in urinary CaOx crystallization inhibitory protein levels.

Experience with hormone receptors in renal cancer

The hormone receptor concentrations in tumour tissues from 20 renal carcinoma patients were determined before postoperative medroxyprogesterone acetate (MPA) therapy was started. Except for glucocorticoid receptors, the concentrations were either not measurable or were extremely low. The question is whether MPA therapy, solely on the strength of its character as a general roborant, is still useful in the treatment of renal tumours, even when it fails to exercise primary influence because of the absence of suitable receptors. None of the 20 patients was treated with MPA.

Influence of sex hormones on pancreatic cancer

A possible new approach to treating pancreatic cancer has been suggested, since the presence of estrogen receptors, estrogen binding proteins, estramustin binding protein, and androgen receptors have been demonstrated in human pancreatic adenocarcinomas of ductular origin. Moreover, there is some evidence that there is a dysfunction of the hypothalamic-sex-organ axis, resulting in low values of gonadotropins as well as testosterone in serum. Confirmatory evidence that all these findings have therapeutic implications in humans is still lacking, but in experimental studies, inhibition as well as growth potentiation of pancreatic cancer can be demonstrated after hormonal manipulations.

Estrogen and progesterone binding sites in renal cell carcinoma

Twenty-five renal cell carcinomas were assayed for estrogen and progesterone receptor levels. Estrogen specific binding was present in only 4 patients (16%) and progesterone specific binding in 7 patients (28%). In all cases these receptors were present in very low titers, less than 10 fm/mg. We believe that earlier reports citing significant estrogen and progesterone binding activity may reflect high levels of nonspecific protein binding.

Androgen influence on exocrine pancreatic cancer

Since the discovery of the first gastrointestinal hormones it has been intriguing to think that these defined chemical messengers may also influence the growth of tumors. Today, treatment with sex-hormones is well documented--and used in clinical practice--in prostatic (1,2), breast (3), endometrial, and ovarian carcinoma (4). Hormonal therapy (progesterone) has also been tried with some success in renal carcinoma (5,6). Nevertheless, cancers of the gastrointestinal tract--colorectal, liver, stomach, and pancreatic, carcinoma, which constitute 25 percent of all malignancies in Scandinavia--are only treated by other means, mainly surgery, although there is substantial evidence today that these tumors can also be influenced by hormones.

Adjuvant medroxyprogesterone acetate and steroid hormone receptors in category M0 renal cell carcinoma. An interim report of a prospective randomized study

From July 1, 1979 to June 30, 1983, 136 consecutive patients with category M0 renal cell cancer who had undergone transperitoneal radical nephrectomy at 5 centers entered a prospective randomized trial to compare 500 mg. adjuvant medroxyprogesterone 3 times a week for 1 year to no treatment. Sex steroid hormone receptors also were studied in the renal tumor and in the surrounding healthy parenchyma with the dextran-coated charcoal technique. After a median followup period of 3 years (range 13 to 60 months) 30 of 121 evaluable patients (24.8 per cent) experienced relapse, usually in the lung or bones. Relapses occurred in 15 of 58 evaluable patients in the adjuvant treatment group (25.8 per cent) and 15 of 63 evaluable controls (23.8 per cent). The disease recurred more frequently (35.1 per cent) in the 57 patients with no receptors in the tumor than in the 45 with at least 1 receptor (17.8 per cent). These results were independent of adjuvant therapy. After a median 3-year followup, adjuvant medroxyprogesterone acetate was of no therapeutic benefit in patients who had undergone radical nephrectomy and the side effects of the therapy were evident in more than 50 per cent of the patients.

Increased dihydrotestosterone receptor levels in high-stage renal adenocarcinoma

Primary renal adenocarcinoma tissue, metastatic deposits, and normal kidney parenchyma from 16 patients were assayed for sex hormone receptors by dextran-coated charcoal adsorption and sucrose gradient centrifugation techniques. Dihydrotestosterone receptors (DHTR) were found in all renal carcinomatous tissue (20/20) and in 93% (13/14) autologous normal kidneys analyzed. Testosterone receptors were found in 84% (16/19) of tumors and 93% (14/15) or normal kidneys analyzed. Estrogen receptors in small amounts (ER) were detected in only 5% (1/19) of tumors and in 7% (1/15) of normal kidneys. Progesterone receptors (PR) in low quantities were detected in 30% (6/20) of renal tumors and in 40% (6/15) of normal kidneys. DHTR levels in high-stage tumors (T3, T4) were significantly elevated over levels in autologous normal kidney, whereas in low-stage tumors localized to the kidney (T1 and T2 tumors) DHTR levels were not significantly different from autologous normal kidney. The mean levels of DHTR in high-stage kidney tumors were significantly elevated over levels in low-stage tumors (P less than 0.001). DHTR estimation in renal neoplasms may help in biologic staging of renal adenocarcinoma and could define a group of patients in whom anti-androgen therapy may be worth a trial.