Hormonal Management of Stage D Carcinoma of the Prostate

Cancer stem cell in prostate cancer progression, metastasis and therapy resistance

Prostate cancer (PCa) is the most diagnosed malignancy in the men worldwide. Cancer stem cells (CSCs) are the sub-population of cells present in the tumor which possess unique properties of self-renewal and multilineage differentiation thus thought to be major cause of therapy resistance, disease relapse, and mortality in several malignancies including PCa. CSCs have also been shown positive for the common stem cells markers such as ALDH EZH2, OCT4, SOX2, c-MYC, Nanog etc. Therefore, isolation and characterization of CSCs specific markers which may discriminate CSCs and normal stem cells are critical to selectively eliminate CSCs. Rapid advances in the field offers a theoretical explanation for many of the enduring uncertainties encompassing the etiology and an optimism for the identification of new stem-cell targets, development of reliable and efficient therapies in the future. The emerging reports have also provided unprecedented insights into CSCs plasticity, quiescence, renewal, and therapeutic response. In this review, we discuss the identification of PCa stem cells, their unique properties, stemness-driving pathways, new diagnostics, and therapeutic interventions.

Androgen Deprivation Therapy for Prostate Cancer

In the contemporary scene, less than 5% of men with newly diagnosed prostate cancer (PC) have metastases at first presentation, compared to 20-25%, more than 20 years ago. Nonetheless, the use of androgen deprivation therapy (ADT) has increased over the years, suggesting that patients in Europe and United States may receive ADT in cases of lower disease burden, and not always according to evidence based indications. Nonetheless, PC remains the second most common cause of cancer death after lung cancer in American men. Thus, there is a need for more effective, specific and well tolerated agents which can provide a longer and good quality of life while avoiding the side effects related to disease and treatment morbidity.After mentioning the current knowledge on the endocrinology of androgens and androgen receptor, relevant to PC development, as well as the possible events occurring during PC initiation, we will compare different hormonal compounds available for the treatment of PC, both from a pharmacological standpoint, and in terms of contemporary clinical indications.

Mechanism of dihydroartemisinin-induced apoptosis in prostate cancer PC3 cells: An iTRAQ-based proteomic analysis

AIMS

Prostate cancer (PCa) is one of the most common cancers in men in the world. Advanced PCa, especially castration-resistant PCa (CRPC), is difficult to cure. There is an urgent need to develop novel agents for CPRC. Dihydroartemisinin (DHA) is a semisynthetic derivative of artemisinin and is a well-known antimalarial drug. DHA has been documented to be a potential anticancer agent for PCa. However, the mechanisms underlying the anticancer activity of DHA are still unknown.

MAIN METHODS

Proteomics analysis based on iTRAQ technology was performed to determine the protein profile changes in human prostate cancer PC3 cells treated by DHA, and apoptosis was detected by flow cytometry and transmission electron microscopy.

KEY FINDINGS

DHA induced obvious apoptosis in PC3 cells. Using iTRAQ technology, we found 86 differentially expressed proteins linked to the cytotoxicity of DHA in PC3 cells. Gene ontology analysis showed the differentially expressed proteins were mainly associated with the protein synthesis and translation. Protein interaction network analysis and KEGG pathway analysis revealed altered aminoacyl-tRNA biosynthesis and metabolic pathways. Moreover, one candidate protein, heat shock protein HSP70 (HSPA1A), was identified by western blot analysis.

SIGNIFICANCE

Our results indicate that multiple mechanisms involved in the anticancer activity of DHA in PC3 cells. Decreased HSP70 expression may have an important role in DHA-induced apoptosis in PC3 cells. Our data also provide novel insights into the anticancer mechanisms of DHA.

Impact of androgen deprivation therapy on sexual function

Many patients with prostate cancer for whom androgen deprivation therapy (ADT) is indicated are young and desire to remain sexually active. In such patients, the side effects of androgen therapy on sexual function can be a source of serious reduction in overall quality of life. Providing the appropriate treatment options in this patient population is therefore essential. Nevertheless, treating such patients is challenging and an understanding of the underlying mechanisms of sexual physiology and pathophysiology is crucial to optimal patient care. In this paper, we reviewed what was known regarding the effects of ADT on sexual function in animal models and we also provided a detailed review on the effects of ADT on sexual health in humans and its treatment.

Castration-induced changes in morphology, androgen levels, and proliferative activity of human prostate cancer tissue grown in athymic nude mice

The transplantable human prostate tumor lines PC-82 and PC-EW regress after androgen depletion. The castration-induced decline in tumor volume was faster in the PC-EW tumor (half-life 6 days) than in the PC-82 tumor (half-life 18 days), despite similar castrate androgen levels of less than 3 pmol/g tissue. Androgen ablation of the PC-82 tumor induced a wave of apoptosis, whereas in the PC-EW tumor, necrotic cell death was predominantly observed. The proliferative activity (BrdU index) of PC-82 and PC-EW tumor tissue declined from 3% to less than 1% after castration. After androgen depletion, some proliferative activity remained, the major part of which was localized in the (murine) stromal compartment of the tumors. In contrast to the PC-EW tumors, regrowth of androgen-ablated PC-82 tumors was rapidly induced by androgen resubstitution. The differences in response of these tumor models to androgen depletion and repletion appear to be related to the putative involvement of different cell death pathways. The role of the stroma in these processes is unclear.

The cost and availability of therapeutic options in advanced prostatic carcinoma in Turkey

Advanced prostatic carcinoma may be treated by a variety of methods of endocrine manipulation which affect the production of androgens. This can either be done by bilateral orchiectomy or by a number of drugs. Orchiectomy has two advantages: low cost and being a once-only procedure. This report outlines the costs of various methods of hormonal treatment and compares them with each other in Turkey.

Genitourinary cancer in the elderly

The subject of genitourinary cancer in the elderly becomes increasingly more important as our population of patients older than 50 years expands. Carcinoma of the kidney, bladder, and prostate all have an increasing incidence over the age of 50 and have a predilection for afflicting men more commonly than women. Etiologic factors, especially with bladder and kidney carcinomas, are well documented and in some cases preventable. Screening the urine for hematuria and careful digital rectal examinations may uncover a higher percentage of these malignancies in earlier, more curable stages. Recent advances in the treatment of all of these malignancies have improved survival and quality of life for these patients.

Flutamide: an antiandrogen for advanced prostate cancer

Flutamide is a nonsteroidal pure antiandrogen that acts by inhibiting the uptake and/or binding of dihydrotestosterone to the target cell receptor, thus interfering with androgen action. Flutamide is well absorbed orally and extensively metabolized; its active metabolite, 2-hydroxyflutamide, is formed rapidly and excreted almost entirely by the kidneys. Clinical studies in prostate cancer patients have demonstrated efficacy with flutamide monotherapy in patients who had received no prior treatment, in untreated patients with combined androgen blockade concomitantly with a luteinizing hormone-releasing hormone (LHRH)-agonist, and in relapsed patients. A randomized, placebo-controlled trial demonstrated a 26 percent increase in median survival for patients treated with leuprolide plus flutamide compared with leuprolide plus placebo. When given as monotherapy and in combination with an LHRH-agonist, flutamide is well tolerated. The usual adverse effects are gynecomastia and mild diarrhea when given as a single agent. In combination with an LHRH-agonist, hot flashes, loss of libido, impotence, mild nausea and vomiting, gynecomastia, and diarrhea are commonly reported. However, only diarrhea occurred more frequently in patients treated with leuprolide plus flutamide than in those treated with leuprolide plus placebo. Flutamide is indicated in combination with an LHRH-agonist (e.g., leuprolide) as initial therapy in metastatic (stage D2) prostate cancer. The usual dose is 250 mg po tid given at eight-hour intervals and started concurrently with the LHRH-agonist. Formulary addition is recommended.

Oestrogen dosage in prostatic cancer: the threshold effect?

We present the results of a prospective randomised trial of Estradurin, a long-acting oestrogen preparation (polyoestradiol phosphate), 160 mg per month, compared with bilateral orchiectomy in patients with advanced prostatic carcinoma (T3M1; T4MO/M1). The dose was lower than that usually recommended to induce a consistent fall in serial plasma testosterone levels to within the castrate range. Most patients treated with oestrogen showed an initial clinical and biochemical response equal to that obtained for patients undergoing orchiectomy. The inevitable relapse in hormone sensitivity sometimes occurred very soon after the start of oestrogen treatment. Many patients had poorly suppressed plasma testosterone expressed as a mean of monthly serial measurements, but then responded to secondary orchiectomy. These data only suggest that, in the treatment of hormone-sensitive prostatic carcinoma, it may be necessary to reduce plasma testosterone to midway between castrate and normal ranges. The data support the theory that response to androgen withdrawal is qualitative rather than quantative. The effective dose of oestrogen may therefore be reduced and the risk of thrombo-embolic complications minimised.

Hormonal therapy for advanced prostatic carcinoma

Since the work of Huggins and Hodges, hormonal therapy, i.e., orchiectomy or estrogens, has been the gold standard of treatment for patients with advanced adenocarcinoma of the prostate. Recently, many new drugs have been introduced in the hope of achieving a beneficial response as compared with hormonal therapy, while avoiding some of the adverse effects. Various newer agents are reviewed. It appears that while these agents may be attractive secondary to specific effects, they do not appear to offer any survival advantage over diethylstilbestrol or orchiectomy. Finally, the theory of total androgen blockade is reviewed. Institution of total blockade does not appear to offer a survival advantage over standard androgen blockade.