Epidemiology of male osteoporosis and prostate cancer

Exosomes derived from PC-3 cells suppress osteoclast differentiation by downregulating miR-148a and blocking the PI3K/AKT/mTOR pathway

Prostate cancer is a leading malignancy in men that can also disrupt the bone tissue balance. Among all urological cancers, prostate cancer is associated with the highest rate of bone metastases, which can greatly reduce a patient's quality of life. In recent years, cell-derived exosomes, which can contain a wide range of biologically active molecules, have been reported as a novel method of communication among individual cells. However, the specific role that exosomes serve in this disease has not been fully elucidated. The prostate cancer cell line PC-3 were applied in the present study, where its exosomes were isolated to explore their potential effects on osteoclast differentiation. Exosomes are extracellular vesicles secreted by cells. The size of exosomes is 30-150 nm. They have double membrane structure and saucer-like morphology. They contain rich contents (including nucleic acid, protein and lipid) and participate in molecular transmission between cells. The combined results of tartrate-resistant acid phosphatase staining (to identify osteoclasts obtained from human peripheral blood mononuclear cells), reverse transcription-quantitative PCR and western blotting showed that PC-3-derived exosomes attenuated osteoclast differentiation by downregulating marker genes associated with osteoclastic maturation, including V-maf musculoaponeurotic fibrosarcoma oncogene homolog B, matrix metalloproteinase 9 and integrin β3. microRNA (miR)-148a expression was also found to be downregulated in osteoclasts by PC-3-derived exosomes. In addition, the mTOR and AKT signaling pathways were blocked after exposure to these PC-3 cell-derived exosomes. Therefore, results from the present study suggest that miR-148a mimics may be a new therapeutic approach for the prevention of prostate cancer bone metastases.

Decrease of bone mineral density in Japanese patients with non-metastatic prostate cancer treated with androgen deprivation therapy

The aim of this study was to conduct a cross-sectional survey of investigations related to the bone mineral density (BMD) of both non-metastatic prostate cancer (NMPC) patients who have not yet received androgen deprivation therapy (ADT) and patients receiving prolonged ADT in Japan. Japanese male patients with NMPC who received continuous ADT or who were planning to receive ADT were enrolled in this study. Lumbar spine and femoral neck BMD was measured using dual-energy X-ray absorptiometry (DEXA). To assess patient characteristics, we searched medical records and questionnaires to determine whether they had any factors that could possibly affect BMD. A total of 230 patients with a mean age of 76.6 ± 6.4 years were evaluated. Of these, 151 (65.7%) were receiving ADT, and 79 (34.4%) had not yet received ADT. The mean duration of ADT was 37.4 ± 30.7 months. DEXA showed that as the duration of ADT increased, lumbar spine and femoral neck BMD decreased gradually (p = 0.0005 and p = 0.0014, respectively). Stepwise regression analyses revealed that the duration of ADT was a significant variable of both lumbar spine and femoral neck BMD. Moreover, as the duration of ADT increased, the prevalence of osteoporosis increased statistically (p = 0.0002). This study showed that ADT negatively affected lumbar spine and femoral neck BMD. It also showed a progressive increase in the prevalence of osteoporosis in Japanese NMPC patients with ADT.

Androgen Deprivation in Veterans with Prostate Cancer: Implications for Skeletal Health

Background:

Common risk factors for osteoporosis in older men include smoking, heavy use of alcohol, propensity to falls, and use of bone-toxic medications such as prednisone. There is also increasing appreciation of the skeletal risk faced by men receiving androgen deprivation therapy (ADT) for prostate cancer. Measures to prevent bone loss in such patients are available.

Objective:

To test the following hypotheses in a population of veterans receiving ADT for prostate cancer: (1) fracture risk factors in addition to androgen deprivation would be found in most patients, (2) bone mass measurements would be assessed in a minority of patients, and (3) a minority of the subjects would receive bisphosphonate therapy or have contraindications for such treatment.

Methods:

We conducted a retrospective chart review of male veterans receiving ADT from 1993 through 2001, at the Veterans Affairs Medical Center, Madison, WI.

Results:

One hundred and seventy-four subjects met study criteria, with a mean age of 76 years and median duration of 21 months of ADT. Eighty-one percent had risk factors in addition to ADT. Only 13% underwent bone density measurement by dual energy X-ray absorptiometry (DXA) and, of those measured, more than half had osteoporosis. Only 19% of the men received both calcium and vitamin D supplements. Antiresorptive therapy was provided to 11% of men, although more than two-thirds had no contraindications to therapy. A total of 24 men sustained a fracture after starting ADT. For men who did undergo bone density measurement, 77% received antiresorptive therapy. Of those who exhibited osteoporosis by DXA scan, 85% received antiresorptive therapy.

Conclusions:

Male veterans receiving ADT for prostate cancer received inadequate evaluation and treatment for osteoporosis. Based on our data, a simple and practical strategy to prompt further evaluation and improved care may be to undertake bone density measurements in men prior to or soon after commencing ADT.

Stimulation of cannabinoid receptors by using Rubus coreanus extracts to control osteoporosis in aged male rats

A substantial proportion of men with prostatic disease have an increased risk of bone loss. In the present study, we investigated the effects of Rubus coreanus Miquel (RCM) extracts on osteoporosis that occurs with N-methyl-N-nitrosourea (MNU)-induced prostatic hyperplasia. The rats used in this study were categorized into groups of healthy controls, rats treated with MNU, and rats treated with MNU and RCM. The rats were sacrificed after 10 weeks of RCM treatment, after which ultrasonography, serum biochemical tests, histopathological examinations, immunohistochemical analysis, and semi-quantitative reverse-transcription polymerase chain reaction analysis were performed. There were no marked differences in body weight gain and the size and weight of the prostate gland between the MNU group and the MNU and RCM group. However, treatment with RCM inhibited osteoclastic osteolysis and reduced dysplastic progress in the prostate gland, as observed by histopathological evaluation and by analyzing changes in the levels of bone regulatory factors. In addition, the group treated with MNU and RCM had higher expression levels of cannabinoid receptors-1, -2, and osteoprotegerin. These results indicate that the anti-osteoporotic effect of RCM in prostatic hyperplasia is attributable to the cannabinoid receptor-related upregulation of osteoblastogenesis and inhibition of prostatic hyperplasia. The results of the present study suggest that treatment with RCM may benefit osteoporotic patients with prostatic disease by simultaneously altering the activation of osteoblasts and osteoclasts.

Male osteoporosis

Osteoporosis develops in males approximately 10 years later than in females. Low vitamin D is a common problem. Decline in testosterone represents a major cause for osteoporosis in men. Bisphosphonates are the treatment of choice for osteoporosis in older males.

The impact of diet and micronutrient supplements on the expression of neuroendocrine markers in murine Lady transgenic prostate

BACKGROUND

Neuroendocrine (NE) differentiation (NED) in prostate cancer (PCa) is associated with morbidity and death; however, the underlying cause(s) promoting NED in PCa have yet to be determined. In this study, we examined the effect of both diet and micronutrient supplementation on the expression of NE markers using the Lady (12T-10) transgenic model of PCa. Lady (12T-10) transgenic animals develop advanced adenocarcinoma with NE characteristics that exhibits metastases in approximately 80% of cases. In this model a high fat diet has been shown to increase the severity of disease, while the use of micronutrients can inhibit this progression.

METHODS

In this study we used immunohistochemical analysis to determine expression of the NE markers: chromogranin A (CgA), neuron-specific enolase (NSE), bombesin, parathyroid hormone-related peptide (PTHrP), neurotensin and serotonin in prostates of PCa-bearing Lady (12T-10) mice.

RESULTS

High fat diet was correlated with significantly elevated expression of CgA and serotonin in prostate tissue of Lady (12T-10) mice. Addition of micronutrients to the control and high fat diet reproducibly elevated PTHrP and bombesin expression and suppressed NSE expression, while prostate tissue from the control diet supplemented with micronutrients exhibited significantly lower numbers of calcitonin- and neurotensin-positive cells.

CONCLUSIONS

These results highlight the importance of dietary control in management of disease and identify differential changes in NE marker expression, which may be diagnostically viable in monitoring the impact of therapies on disease status.

Prevalence of Osteoporosis During Long-Term Androgen Deprivation Therapy in Patients with Prostate Cancer

OBJECTIVES

To know the prevalence of osteoporosis in patients with prostate cancer according to the duration of androgen deprivation therapy (ADT).

METHODS

Dual energy x-ray absorptiometry was used to assess the bone mineral density (BMD) at the lumbar spine, femoral neck, Ward's triangle, trochanter, and total hip in 390 patients free of bone metastases. Osteoporosis was diagnosed if a T-score of less than 2.5 was detected at any measurement site. A subset of 124 patients were hormone naive at BMD testing, and 112 had undergone ADT for 2 years, 61 for 4 years, 37 for 6 years, 35 for 8 years, and 21 for 10 years or longer.

RESULTS

The osteoporosis rate was 35.4% in hormone-naive patients, 42.9% after 2 years of ADT, 49.2% after 4 years, 59.5% after 6 years, 65.7% after 8 years, and 80.6% after 10 or more years. Conversely, the rate of normal BMD decreased from 19.4% in hormone-naive patients to 17.8% after 2 years of ADT, 16.4% after 4 years, 10.8% after 6 years, 5.7% after 8 years, and 0% after 10 or more years of ADT.

CONCLUSIONS

The prevalence of osteoporosis seemed high in hormone-naive patients with prostate cancer, and it increased to more than 80% after 10 years of ADT. Because of the increased risk of bone fractures in those patients, clinicians should be aware of the impact of ADT on BMD to prevent bone mass loss.

Goserelin acetate in combination with radiotherapy for prostate cancer

Improvements in longer-term survival rates have been demonstrated for locally advanced prostate cancer patients treated with adjuvant androgen deprivation therapy (ADT), and in subsets of men with clinically localized disease treated with ADT combined with external-beam radiotherapy (RT). In these studies, ADT was administered in the form of surgery (orchiectomy) or with a class of drugs called luteinizing hormone-releasing hormone agonists. Goserelin acetate is a member of this class, and 10 of 11 major Phase III trials demonstrating better outcomes with ADT and RT used goserelin acetate. The reduction in deaths from prostate cancer noted in the mid-1990s may largely be due to the early use of these agents in men with intermediate-to-high-risk disease.

Bone and prostate cancer cell interactions in metastatic prostate cancer

The interplay in prostate cancer bone metastases between the 'seed' (the prostate cancer cells) and the 'soil' (the bone microenvironment) has been increasingly recognized as integral to the remarkable tropism for bone shown by prostate cancer. Increasing research into this area is elucidating the mechanisms involved in this complex 'cross-talk'. Recent developments, including the use of bisphosphonates in metastatic disease, highlight the important role of bone cells in the development and progression of metastatic prostate cancer. We review the current reports emphasising these possible mechanisms and indicating possible factors for future treatment directions.

MR imaging and osteoporosis: fractal lacunarity analysis of trabecular bone

We develop a method of magnetic resonance (MR) image analysis able to provide parameter(s) sensitive to bone microarchitecture changes in aging, and to osteoporosis onset and progression. The method has been built taking into account fractal properties of many anatomic and physiologic structures. Fractal lacunarity analysis has been used to determine relevant parameter(s) to differentiate among three types of trabecular bone structure (healthy young, healthy perimenopausal, and osteoporotic patients) from lumbar vertebra MR images. In particular, we propose to approximate the lacunarity function by a hyperbola model function that depends on three coefficients, alpha, beta, and gamma, and to compute these coefficients as the solution of a least squares problem. This triplet of coefficients provides a model function that better represents the variation of mass density of pixels in the image considered. Clinical application of this preliminary version of our method suggests that one of the three coefficients, beta, may represent a standard for the evaluation of trabecular bone architecture and a potentially useful parametric index for the early diagnosis of osteoporosis.