Estrogen treatment postpones the castration-induced dedifferentiation of Dunning R3327-PAP prostatic adenocarcinoma

The implications of hormone treatment for cancer risk, screening and treatment in transgender individuals

There is evidence that gender-affirming hormone treatment (GAHT) for transgender individuals modulates their risk for specific malignancies including breast and prostate cancer, and meningiomas. However, there is insufficient data to make precise risk estimates accounting for age and inherited cancer risk. As such, screening recommendations remain broad. Even less evidence exists for best practice in the management of active or historical cancers in the transgender population. Guidance is therefore mainly extrapolated from cisgender populations but with considerations of the significant benefits of GAHT in the face of any hormonal risk. Clinical experience, the multidisciplinary team and shared decision making with the patient are vital in providing person-centred care, while further research is acquired.

Prostate cancer in transgender women: considerations for screening, diagnosis and management

Transgender individuals represent 0.55% of the US population, equivalent to 1.4 million transgender adults. In transgender women, feminisation can include a number of medical and surgical interventions. The main goal is to deprive the phenotypically masculine body of androgens and simultaneously provide oestrogen therapy for feminisation. In gender-confirming surgery (GCS) for transgender females, the prostate is usually not removed. Due to limitations of existing cohort studies, the true incidence of prostate cancer in transgender females is unknown but is thought to be less than the incidence among cis-gender males. It is unclear how prostate cancer develops in androgen-deprived conditions in these patients. Six out of eleven case reports in the literature presented with metastatic disease. It is thought that androgen receptor-mediated mechanisms or tumour-promoting effects of oestrogen may be responsible. Due to the low incidence of prostate cancer identified in transgender women, there is little evidence to drive specific screening recommendations in this patient subpopulation. The treatment of early and locally advanced prostate cancer in these patients warrants an individualised thoughtful approach with input from patients' reconstructive surgeons. Both surgical and radiation treatment for prostate cancer in these patients can profoundly impact the patient's quality of life. In this review, we discuss the evidence surrounding screening and treatment of prostate cancer in transgender women and consider the current gaps in our knowledge in providing evidence-based guidance at the molecular, genomic and epidemiological level, for clinical decision-making in the management of these patients.

Androgen deprivation therapy: progress in understanding mechanisms of resistance and optimizing androgen depletion

Androgen deprivation therapy remains a critical component of treatment for men with advanced prostate cancer, and data support its use in metastatic disease and in conjunction with surgery or radiation in specific settings. Alternatives to standard androgen deprivation therapy, such as intermittent androgen suppression and estrogen therapy, hold the potential to improve toxicity profiles while maintaining clinical benefit. Current androgen deprivation strategies seem to incompletely suppress androgen levels and androgen-receptor-mediated effects at the tissue level. Advances in the understanding of mechanisms that contribute to castration-resistant prostate cancer are leading to rationally designed therapies targeting androgen metabolism and the androgen receptor. The results of large trials investigating the optimization of primary androgen deprivation therapy, including evaluation of intermittent androgen suppression and phase III studies of novel androgen synthesis inhibitors, such as abiraterone acetate, are eagerly awaited.

Molecular profile of androgen-independent prostate cancer xenograft LuCaP 23.1

After castration or therapeutic hormone deprivation, most cancer of the prostate (CaP) cells develop androgen-independent (AI) growth. In this work, we studied the effect of androgen depletion (castration) on the growth of experimental model LuCaP 23.1 xenograft. A total of 101 nude mice were implanted and analysed for their growth profile before experimental period 1 (11 weeks) and after castration experimental period 2 (15 weeks). For specific periods, tumors were harvested and assessed for molecular marker expression specific for CaP. Taking into account tumor dynamic growth, prior to castration we found 37 fast growing (FG) tumors (948.9+/-76.9 mm3) and 63 slow growing (SG) tumors (229.6+/-18.4 mm3). Real-time quantitative RT-PCR showed that in comparison to SGs, FGs contained elevated expression of epidermal growth factor receptor type 1 (HER1), urokinase plasminogen activator (uPA), thymidine phosphorylase (TP) and thymidilate synthase (TS) mRNAs expression and low levels of 5alpha-reductase 2 (5alpha-R2) mRNA. After castration all FG tumors progressed rapidly (by 5 weeks) to AI growth (FG-P). In SG castrated tumors, 66% of tumors showed retarded progression (by 12 weeks) to AI (SG-P), whereas 34% responded to castration (SG-R). Molecular analysis demonstrated distinct molecular profiles integrating different pathways associated with AI progression. The progressive tumors FG-P, and some tumors of SG-P subgroup, presented significantly high levels of HER1, epidermal growth factor receptor type 2 (HER2), TS, uPA, TP, tumor necrosis factor superfamily member 6 (FAS) and peptidylglycine alpha-amidating mono-oxygenase (PAM) mRNA all of which correlated with androgen receptor (AR) mRNA. The second subgroup of SG-P tumors showed a high expression of the anti-apoptotic gene Bcl-2. A third subgroup of SG-P tumors showed significant expression of hypoxia-related genes such as adrenomedullin (AM) after castration. LuCaP 23.1 xenograft represent a useful dynamic model to study pre-clinically new therapeutic molecules and evaluate non-randomized therapeutics protocols combining different target inhibition specific to each AI pathways.

Medical versus surgical androgen suppression therapy for prostate cancer: a 10-year longitudinal cost study

PURPOSE

We provide a relative cost comparison of medical versus surgical androgen suppressive therapy for prostate cancer.

MATERIALS AND METHODS

Comparison is based on a cohort of 96 patients who began androgen suppressive therapy for prostate cancer between 1988 and 1990. Patients were followed until death or the end point of study in June 2000 at which time 15% were alive. Current Medicare orchiectomy reimbursements were compared to 1999 wholesale drug costs.

RESULTS

For an individual patient the cost of luteinizing hormone releasing hormone (LH-RH) agonist treatment surpassed the cost of surgery at less than 4.2 to 5.3 months, and for combined androgen blockade (LH-RH agonists and nonsteroidal antiandrogens) at less than 2.7 to 3.4 months. For 5 (5.2%) patients on combined androgen blockade and 6 (6.3%) on LH-RH agonists alone, medical therapy would have had a cost advantage over bilateral orchiectomy. For the androgen suppression cohort the cost of LH-RH agonist treatment was 10.7 to 13.5 times and combined androgen blockade was 17.3 to 20.9 times the cost of bilateral orchiectomy. Urology resource use comparisons are provided. These findings significantly underestimate the cost advantage of surgery. A seventh of the patients were alive at study end point, and prostate specific antigen induced stage shifting and changes in practice patterns resulted in earlier and more frequent androgen suppressive treatment.

CONCLUSIONS

Except for patients with short anticipated survivals current medical androgen suppressive treatment options are more costly than bilateral orchiectomy. There is a need for a cost comparable medical option to orchiectomy.

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.

Fractionated radiotherapy of rat prostatic adenocarcinoma (Dunning R3327-PAP) in nonanesthetized animals

BACKGROUND

The dose-response effect of fractionated external beam radiotherapy on nonanesthetized rats bearing the androgen-sensitive prostatic adenocarcinoma Dunning R3327-PAP was studied.

METHODS

The radiation was given with a photon beam from a 4-MeV linear accelerator in doses from 4 to 11 Gray per fraction during 5 consecutive days. When the tumors with low and intermediate radiation doses relapsed into regrowth, the rats were castrated. Tumor volumes and rat weights were followed, and at the end of the study a morphometric analysis of the tumors was done.

RESULTS

Fractionated irradiation induced a dose-dependent delay in tumor growth in hormonally intact rats. Castration stopped the tumor regrowth, showing that some of the tumor cells were still hormone-sensitive. The study was facilitated by the nonanesthesia procedure.

CONCLUSIONS

The Dunning R3327-PAP hormone-sensitive rat tumor is sensitive to radiotherapy in a dose-dependent way. Regrowing, irradiated tumors contain hormone-sensitive cells. This work provided basic knowledge for further experimental studies of the effects of radiation on prostatic adenocarcinoma.

Inhibitory effects of soy and rye diets on the development of Dunning R3327 prostate adenocarcinoma in rats

METHODS

Dunning R3327 PAP prostate tumors were transplanted in 125 rats, the rats were divided into five groups, and tumor development was examined for 24 weeks during treatment with diets containing 33% of soy flour (SD), rye bran (RB), heat-treated rye bran (HRB), or rye endosperm (RE).

RESULTS

In the SD, RB, and HRB groups, significantly fewer palpable tumors and lower tumor volume were detected 14 and 16 weeks after transplantation when compared with the control, fiber-free dietary (FF) group. The body weight was lower 16 weeks after tumor transplantation in the RB and HRB groups when compared with the control group (P < 0.05). Rats in the RB and the HRB groups had a significant lower energy intake than the FF group during the first metabolic observation period, 3-6 weeks after tumor transplantation (P < 0.05), whereas the energy intake was the same in all groups during the second metabolic observation period, 13-16 weeks after tumor transplantation. However, when the tumor volume was adjusted for the body weight of the animals, there were still significant lower tumor volumes in the SD, RB, and HRB groups compared with the FF group (P < 0.05). A significant increase in daily urinary excretion of the isoflavonoids, daidzein, O-desmethylangolensin, equol, and Genistein, was observed in the rats fed SD, and of the ligands enterolactone and enterodiol in the rats fed RB and HRB during both metabolic periods. There were no differences in testosterone levels between the groups.

CONCLUSIONS

The present study shows that SD inhibits implanted prostate cancer growth. Although RB and HRB had a protective effect, further studies are needed to exclude the possibility that a low energy intake played a role in this respect. The results suggest that phytoestrogens (isoflavonoids and ligands), may be responsible for the delayed prostate tumor growth.

Estrogen induces apoptosis in a rat prostatic adenocarcinoma: association with an increased expression of TGF-beta 1 and its type-I and type-II receptors

Rats transplanted with the androgen-sensitive Dunning R3327 PAP prostatic adenocarcinoma were castrated and treated with either estrogen or vehicle alone for short periods (4 hr, 12 hr, 24 hr) and for 6 weeks. In these tumors the expression of TGF-beta 1, TGF-beta type-I and type-II receptors (TGF-beta RI, TGF-beta RII) was examined by immunohistochemistry. Apoptotic cells were identified by in situ nick and labelling (TUNEL). Tumor growth was retarded by castration and even more by additive estrogen treatment. The epithelium of the untreated tumors stained weakly for TGF-beta 1 and TGF-beta RI, but TGF-beta RII was not detected. Castration induced moderate TGF-beta 1 immunoreactivity in a major part of the glandular epithelium after 24 hr. After 12 hr already, castration plus estrogen resulted in an intense staining for TGF-beta 1 in the basal epithelial cells, some of which also showed an apoptotic appearance. The percentage of cells having stained positive for TGF-beta 1 was significantly higher in the estrogen-treated groups than in the castrated group after 12 hr, and its elevated TGF-beta 1 level remained at 6 weeks. Notably, the increased immunoexpression of TGF-beta 1 occurred before the onset of induction of apoptosis. In parallel with the upregulation of TGF-beta 1 after castration, the expression of its receptors. TGF-beta RI and RII, was induced and was further enhanced by the additive estrogen treatment. The number of intensely stained TGF-beta 1 tumor cells showed a strong correlation with the number of apoptotic tumor cells identified by TUNEL in the whole material. Furthermore, TGF-beta 1 immunoreactivity co-localized with the presence of apoptotic cells in the estrogen-treated tumors at 6 weeks after castration.