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At least 235 records · Page 13Linked to original sources
PubMed2006

Galectin-3 regulates mitochondrial stability and antiapoptotic function in response to anticancer drug in prostate cancer.

Prostate cancer is one of the malignant tumors which exhibit resistance to anticancer drugs, at least in part due to enhanced antiapoptotic mechanisms. Therefore, the understanding of such mechanisms should improve the design of chemotherapy against prostate cancer. Galectin-3 (Gal-3), a multifunctional oncogenic protein involved in the regulation of tumor proliferation, angiogenesis, and apoptosis has shown antiapoptotic effects in certain cell types. Here, we show that the expression of exogenous Gal-3 in human prostate cancer LNCaP cells, which do not express Gal-3 constitutively, inhibits anticancer drug-induced apoptosis by stabilizing the mitochondria. Thus, Gal-3-negative cells showed 66.31% apoptosis after treatment with 50 micromol/L cis-diammine-dichloroplatinum for 48 hours, whereas two clones of Gal-3-expressing cells show only 2.92% and 1.42% apoptotic cells. Similarly, Gal-3-negative cells showed 43.8% apoptosis after treatment with 300 micromol/L etoposide for 48 hours, whereas only 15.38% and 14.51% of Gal-3-expressing LNCaP cells were apoptotic. The expression of Gal-3 stimulated the phosphorylation of Ser(112) of Bcl-2-associated death (Bad) protein and down-regulated Bad expression after treatment with cis-diammine-dichloroplatinum. Gal-3 also inhibited mitochondrial depolarization and damage after translocation from the nuclei to the cytoplasm, resulting in inhibition of cytochrome c release and caspase-3 activation. These findings indicate that Gal-3 inhibits anticancer drug-induced apoptosis through regulation of Bad protein and suppression of the mitochondrial apoptosis pathway. Therefore, targeting Gal-3 could improve the efficacy of anticancer drug chemotherapy in prostate cancer.

Apoptosis↗
PubMed2005

Pomegranate fruit juice for chemoprevention and chemotherapy of prostate cancer.

Prostate cancer is the most common invasive malignancy and the second leading cause of cancer-related deaths among U.S. males, with a similar trend in many Western countries. One approach to control this malignancy is its prevention through the use of agents present in diet consumed by humans. Pomegranate from the tree Punica granatum possesses strong antioxidant and antiinflammatory properties. We recently showed that pomegranate fruit extract (PFE) possesses remarkable antitumor-promoting effects in mouse skin. In this study, employing human prostate cancer cells, we evaluated the antiproliferative and proapoptotic properties of PFE. PFE (10-100 microg/ml; 48 h) treatment of highly aggressive human prostate cancer PC3 cells resulted in a dose-dependent inhibition of cell growth/cell viability and induction of apoptosis. Immunoblot analysis revealed that PFE treatment of PC3 cells resulted in (i) induction of Bax and Bak (proapoptotic); (ii) down-regulation of Bcl-X(L) and Bcl-2 (antiapoptotic); (iii) induction of WAF1/p21 and KIP1/p27; (iv) a decrease in cyclins D1, D2, and E; and (v) a decrease in cyclin-dependent kinase (cdk) 2, cdk4, and cdk6 expression. These data establish the involvement of the cyclin kinase inhibitor-cyclin-cdk network during the antiproliferative effects of PFE. Oral administration of PFE (0.1% and 0.2%, wt/vol) to athymic nude mice implanted with androgen-sensitive CWR22Rnu1 cells resulted in a significant inhibition in tumor growth concomitant with a significant decrease in serum prostate-specific antigen levels. We suggest that pomegranate juice may have cancer-chemopreventive as well as cancer-chemotherapeutic effects against prostate cancer in humans.

Animals↗
PubMed2002

Background to and management of treatment-related bone loss in prostate cancer.

Prostate cancer is a common disease among older men. Androgen suppression by either orchiectomy or administration of luteinising hormone-releasing hormone (LHRH) analogues is the mainstay of treatment. Since the use of prostate-specific antigen (PSA) serum testing has become widespread, however, the timing of endocrine therapy has expanded considerably to include patients with limited involvement of extraprostatic sites and patients presenting an isolated elevation of PSA after radical treatments. These patients are expected to be treated for a long time, since they have a rather low risk of disease progression and there is no recommended time limit for LHRH analogue therapy. The long-term adverse effects of androgen deprivation therapy, therefore, deserve more attention than they have received in the past. Osteoporosis represents a special concern for men with prostate cancer receiving androgen deprivation therapy. The rate of bone loss in these men seems to markedly exceed that associated with menopause in women, and fractures occur more frequently than in the healthy elderly male population. Serial bone mineral density (BMD) evaluation could allow the detection of patients with prostate cancer who are at greater risk of osteoporosis and adverse skeletal events after androgen deprivation therapy, such as patients already osteopenic or osteoporotic at baseline and men with rapid bone loss during treatment. BMD evaluated during treatment could also be a potential surrogate parameter of antiosteoporotic therapeutic efficacy. Treatment of bone loss induced by androgen deprivation comprises general prevention measures, antiosteoporotic drugs and the use of alternative endocrine therapies. Optimising lifestyle and diet is important, although it cannot completely prevent bone loss. Patients with nonsevere bone disease may benefit from calcium and vitamin D supplements. Men who are osteoporotic before androgen deprivation or men becoming osteoporotic during treatment and/or experiencing adverse skeletal events may also require bisphosphonates. The effectiveness of these drugs in preventing fractures has been shown in a single randomised study involving patients with osteoporosis, but it has not yet been established in a prostatic cancer population without bone metastases given androgen deprivation therapy. Different forms of endocrine therapy such as low-dose estrogens, antiandrogens and intermittent androgen ablation are under investigation. They could offer the advantage of avoiding (or limiting) treatment-related bone loss. In our opinion, however, the data available so far are not robust enough to recommend these alternative endocrine therapies instead of standard androgen deprivation in routine clinical practice.

Androgen Antagonists↗
PubMed2003

Adjuvant hormone therapy after radiation or surgery for localized or locally advanced prostate cancer.

Prostate cancer is being diagnosed at an earlier age and earlier disease stage than previously and increasing numbers of relatively young men are receiving potentially curative radical prostatectomy or radiotherapy for early prostate cancer. Although many of these men have an excellent outcome, a significant proportion subsequently experience disease recurrence or cancer-related death. Men with unfavorable tumor characteristics at the time of radical prostatectomy or radiotherapy are particularly at high risk of experiencing disease recurrence. One strategy to improve outcome for these men is adjuvant hormone therapy (hormone therapy administered immediately after therapy of primary curative intent). Surgical castration (bilateral orchiectomy), medical castration using the luteinizing hormone-releasing hormone (LHRH) agonist goserelin, and antiandrogen monotherapy have been investigated as adjuvant hormone therapy to radical prostatectomy and radiotherapy, and each therapy has demonstrated clinical benefits because of a significant improvement in disease-free survival. Furthermore, data are available to indicate that adjuvant hormone therapy achieved by goserelin or bilateral orchiectomy improves overall survival, particularly in men at high risk of progression. Because the effects of LHRH agonists are reversible, they provide a more acceptable method of adjuvant therapy compared to bilateral orchiectomy, particularly in the adjuvant setting, and are preferred by patients. However, the adverse effects on quality of life, in particular on sexual interest and function and bone mineral density, may limit the use of LHRH agonists in some patients. However, these parameters are maintained with nonsteroidal antiandrogens. The first data from the Early Prostate Cancer program indicate that adjuvant bicalutamide 150 mg is associated with a significant improvement in progression-free survival after radical prostatectomy or radiotherapy. Gynecomastia and breast pain are the most common side effects associated with bicalutamide therapy. Medical or surgical castration in combination with an antiandrogen (combined androgen blockade) is another option for use as an adjuvant hormone therapy. However, no study has reported on the use of combined androgen blockade in this setting. Adjuvant hormone therapy provides clinicians with another treatment option for patients with early prostate cancer and unfavorable tumor characteristics.

Aged↗
PubMed1994

Frequent detection of codon 877 mutation in the androgen receptor gene in advanced prostate cancers.

Prostatic tissue specimens derived from transurethral resections of patients with metastatic prostate cancer were analyzed for genetic alterations in the hormone-binding domain of the androgen receptor (AR) gene. Direct sequencing of the polymerase chain reaction-derived DNAs of 6 of 24 specimens revealed a codon 877 mutation (ACT-->GCT, Thr-->Ala) in the hormone-binding domain of the AR gene. This same AR mutation has been reported previously in a metastatic prostate cancer cell line, LNCaP, where this mutation confers upon the AR an altered ligand-binding specificity which is stimulated by estrogens, progestagens, and antiandrogens. It is possible that analogous to an activated/altered growth factor receptor oncogene, codon 877 mutant AR with altered ligand binding may provide a selective growth advantage in the genesis of a subset of advanced prostate cancer. Although estrogens are used infrequently, antiandrogens are used increasingly in hormonal therapy for patients with advanced prostate cancer. The stimulatory effect of these therapeutic agents on the codon 877 mutant AR further suggests that this frequently observed AR mutation may contribute to the treatment refractory disease.

Codon↗
PubMed2006

Amino-terminus domain of the androgen receptor as a molecular target to prevent the hormonal progression of prostate cancer.

Prostate cancer has a propensity to metastasize to the bone. Currently the only effective systemic treatment for these patients is androgen ablation therapy. However, the tumor will invariably progress to an androgen-independent stage and the patient will succumb to his disease within approximately 2 years. The earliest indication of hormonal progression is the rising titer of serum prostate specific antigen. Current evidence implicates the androgen receptor (AR) as a key factor in maintaining the growth of prostate cancer cells in an androgen-depleted state. Under normal conditions, binding of ligand activates the receptor, allowing it to effectively bind to its respective DNA element. However, AR is also transformed in the absence of androgen (ligand-independent activation) in prostate cells via multiple protein kinase pathways and the interleukin-6 (IL-6) pathway that converge upon the N-terminal domain of the AR. This domain is the main region for phosphorylation and is also critical for normal coregulator recruitment. Here we discuss evidence supporting the role of the AR, IL-6 and other protein kinase pathways in the hormonal progression of prostate cancer to androgen independence and the mechanisms involved in activation of the AR by these pathways. Receptor-targeted therapy, especially potential drugs targeting the N-terminal domain, may effectively prevent or delay the hormonal progression of AR-dependent prostate cancer.

Androgen Antagonists↗
PubMed2000

The in vitro evaluation of 25-hydroxyvitamin D3 and 19-nor-1alpha,25-dihydroxyvitamin D2 as therapeutic agents for prostate cancer.

Prostate cancer cells contain specific receptors [vitamin D receptors (VDRs)] for 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3), which is known to inhibit the proliferation and invasiveness of these cells. These findings support the use of 1alpha,25(OH)2D3 for prostate cancer therapy. However, because 1alpha,25(OH)2D3 can cause hypercalcemia, analogues of 1alpha,25(OH)2D3 that are less calcemic but that exhibit potent antiproliferative activity would be attractive as therapeutic agents. We investigated the effects of two different types of less calcemic vitamin D compounds, 25-hydroxyvitamin D3 [25(OH)D3] and 19-nor-1alpha,25-dihydroxyvitamin D2 [19-nor-1,25(OH)2D2], and compared their activity to 1alpha,25(OH)2D3 on (a) the proliferation of primary cultures and cell lines of human prostate cancer cells; and (b) the transactivation of the VDRs in the androgen-insensitive PC-3 cancer cell line stably transfected with VDR (PC-3/ VDR). 19-nor-1alpha,25(OH)2D2, an analogue of 1alpha,25(OH)2D3 that was originally developed for the treatment of parathyroid disease, has been shown to be less calcemic than 1alpha,25(OH)2D3 in clinical trials. Additionally, we recently showed that human prostate cells in primary culture possess 25(OH)D3-1alpha-hydroxylase, an enzyme that hydroxylates the inactive prohormone, 25(OH)D3, to the active hormone, 1alpha,25(OH)2D3, intracellularly. We reasoned that the hormone that is formed intracellularly would inhibit prostate cell proliferation in an autocrine fashion. We found that 1alpha,25(OH)2D3 and 19-nor-1alpha,25(OH)2D2 caused similar dose-dependent inhibition in the cell lines and primary cultures in the [3H]thymidine incorporation assay and that both compounds were significantly more active in the primary cultures than in LNCaP cells. Likewise, 25(OH)D3 had inhibitory effects comparable to those of 1alpha,25(OH)2D3 in the primary cultures. In the chloramphenicol acetyltransferase (CAT) reporter gene transactivation assay in PC-3/ VDR cells, 1alpha,25(OH)2D3 and 19-nor-1alpha,25(OH)2D2 caused similar increases in CAT activity between 10(-11)and 10(-9) M. Incubation of PC-3/VDR cells with 5 x 10(-8) M 25(OH)D3 induced a 29-fold increase in CAT activity, similar to that induced by 10(-8) M 1alpha,25(OH)2D3. In conclusion, our data indicate that 25(OH)D3 and 19-nor-1alpha,25(OH)2D2 represent two different solutions to the problem of hypercalcemia associated with vitamin D-based therapies: 25(OH)D3 requires the presence of 1alpha-hydroxylase, whereas 19-nor-1alpha,25(OH)2D2 does not. Both drugs are approved for human use and may be good candidates for human clinical trials in prostate cancer.

Calcifediol↗
PubMed1999

Pain management in patients with advanced prostate cancer.

Prostate cancer is the most commonly diagnosed cancer among American men. The majority of patients with advanced disease have metastatic bone lesions, which are frequently very painful. These lesions tend to respond well to treatment with both nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids, although careful dose titration and individualized treatment plans may be needed to achieve maximal analgesia. Opioid side effects are often transient or well controlled with additional medication. Patients with intolerable side effects may experience fewer adverse reactions with a different opioid. Palliative radiation provides pain relief in up to 80% of prostate cancer patients with single or at most a few sites of localized bone pain. Bisphosphonates, powerful inhibitors of osteoclast-mediated bone resorption, are promising new agents for the treatment of painful bone lesions in prostate cancer patients. Radioisotopes, which deliver high-dose radiation to bone lesions without significantly affecting normal bone, are highly effective in providing some degree of pain relief in up to 80% of patients with diffuse, painful bone metastases. Also, chemotherapy shows promise in alleviating pain and possibly extending survival in patients with advanced prostate cancer.

Analgesics, Opioid↗
PubMed2006

Chemoprevention of prostate cancer.

Prostate cancer is an attractive target for chemoprevention because of its ubiquity, treatment-related morbidity, long latency between premalignant lesions and clinically evident cancer, and defined molecular pathogenesis. The Prostate Cancer Prevention Trial has provided the first firm evidence that this cancer can be prevented by a relatively nontoxic oral agent. Additional agents, many of which are antioxidants with antiandrogenic effects, are being tested (or soon will be) in large clinical trials. The current body of evidence is insufficient to make a routine recommendation of any dietary or nutritional supplement for the prevention of prostate cancer.

5-alpha Reductase Inhibitors↗
PubMed1990

Growth factors and oncogenes in prostate cancer.

Prostatic cancer is an increasing medical problem. Investigations of the biology of the prostate and the development of prostate cancer have shown that the prostate gland contains high levels of polypeptide growth factors, especially members of the fibroblast growth factor (FGF) and transforming growth factor (TGF)-beta family. Activated oncogenes and elevated proto-oncogene activities including ras and myc have been detected in human prostate cancer tissues, but there is no consensus as to the predominant genetic alterations involved in the progression of this disease. In vivo animal models have shown that relevant growth factors and oncogenes can induce both premalignant and malignant changes in prostate tissue. Additional experimental and clinical studies are needed to present a clearer molecular profile of this important malignancy.

Cell Differentiation↗
PubMed2005

Cellular retinoic acid-binding protein 2 is down-regulated in prostate cancer.

Prostate cancer is among the most frequent tumours in industrialized nations and many questions remain open concerning the molecular events underlying its development and progression. In the present study we have combined cDNA array hybridization to laser-assisted microdissection (LAM) in order to investigate differences in gene expression between epithelial and stromal cells of prostate cancer and normal peripheral prostate tissue. Results have been verified for selected candidate genes by quantitative real-time RT-PCR. Using this approach and immunohistochemistry we could demonstrate a down-regulation of cellular retinoic acid binding protein 2 (CRABP2) mRNA and protein in carcinoma cells compared to normal glandular cells. CRABP2 is a main regulator of anti-carcinogenic activities of retinoic acid and may become a novel diagnostic marker and experimental therapeutic tool for prostate cancer. In addition, results of cDNA array hybridization suggest an up-regulation of 34 further genes and a down-regulation of 6 genes in cancer tissues compared to normal peripheral prostate tissues. Several of these genes have already been reported to be associated with carcinogenesis in organs such as the prostate.

Aged↗
PubMed2004

Aberrant CpG island hypermethylation of multiple genes in prostate cancer and prostatic intraepithelial neoplasia.

To date, several reports have been published about CpG island methylation of various genes in prostate cancer. However, most of these studies have focused on cancer tissue only or a single gene and data about concurrent methylation of multiple genes in prostate cancer or prostatic intraepithelial neoplasia (PIN) are limited. The aim of the present study was to determine the methylation profile of 11 tumour-related genes in prostate cancer and PIN. Seventy-one samples, including 37 prostate cancers, 14 PINs, and 20 normal prostates, were examined for the methylation status of 11 tumour-related genes using methylation-specific PCR. The mean number of genes methylated was significantly higher in prostate cancer and PIN than in non-neoplastic prostate (4.4, 3, and 0.2, respectively; p < 0.001). In prostate cancer, APC, GSTP1, MGMT, and RASSF1A were frequently methylated at a frequency of 56.8%, 86.5%, 75.7%, and 83.8%, respectively. These genes were methylated in more than 30% of PINs. Prostate cancers with high serum prostate-specific antigen (PSA) (more than 8 ng/ml) or a high Gleason score (GS) (3 + 4 or more) showed higher numbers of methylated genes than those with low serum PSA (8 or less) or low GS (3 + 3 or less) (5.4 versus 2.5 and 5.4 versus 3.1, respectively; p < 0.05). The methylation frequency of APC, RASSF1A, and RUNX3 was higher in prostate cancers with high serum PSA or with high GS than in those with low PSA or with low GS, respectively, the differences reaching statistical significance (p < 0.05). A strong association between MGMT methylation and loss of MGMT expression was demonstrated by immunohistochemistry. CpG island methylation is a frequent event, occurs early, and accumulates during multi-step prostatic carcinogenesis. High levels of CpG island hypermethylation might serve as a potential biological marker for aggressive prostate cancer.

Adenocarcinoma↗
PubMed2001

Molecular profiling in prostate cancer.

Prostate cancer is the most diagnosed cancer and the second leading cause of cancer death among men in the United States. Ability to detect this cancer early and availability of better prognostic markers are critical in order to decrease morbidity and mortality of prostate cancer. With the recent development in gene expression analysis methodology, expression profiles of thousands of genes can be generated in tissue samples and cell lines. Comparison of the global gene expression patterns between normal prostate and tumors at different stages may allow us to understand better the molecular mechanism of prostate tumorigenesis and progression. Different cancer cell lines and tissues appear to have different gene expression patterns that provide a new tool to classify tumors. Molecular classification of prostate cancer holds great promise for early detection and prognosis of this disease in the future. In this review, we summarize some of the recent mRNA and protein expression profiling studies performed in prostate cancer. Further, we discuss the potential benefits and limitations of current profiling technology.

Gene Expression Profiling↗
PubMed1991

Phase II study of the pure non-steroidal antiandrogen nilutamide in prostatic cancer. Italian Prostatic Cancer Project (PONCAP).

The activity of the pure non-steroidal antiandrogen nilutamide as a single agent was evaluated in 44 patients with metastatic carcinoma of the prostate. Objective (partial) response rates (95% confidence limits) were 38.5 (18.7)% in 26 previously untreated patients and 5.5 (11%) in 18 patients progressing on primary androgen suppressive procedures. The most frequent side-effects were decreased adaptation to darkness (29.5%), slight nausea (31.8%) and alcohol intolerance (18.2%). In addition, treatment was discontinued in 3 patients because of gastrointestinal symptoms. A non-significant increase in testosterone levels was shown in the untreated group during the first month of treatment, after which the levels remained stable. About half of the sexually active men claimed the maintenance of libido and sexual potency during treatment. Although our study confirms a significant incidence of visual disturbances, the activity data coupled with the ability of maintaining sexual interest suggest that single therapy with non-steroidal antiandrogens may deserve comparison to conventional endocrine treatment in controlled trials.

Aged↗
PubMed2004

Environmental, genetic, and molecular features of prostate cancer.

Prostate cancer is the sixth most common cancer in the world and the third leading cause of cancer in men. The increase in the understanding of prostate carcinogenesis over the past 15 years has helped to define crucial steps in the natural history of the disease, namely initiation and progression to androgen independence. This heterogeneous disease encompasses a range of environmental and familial factors, which provides strong support for the use of chemopreventive strategies. Most patients with advanced prostate cancer are treated with androgen-deprivation therapy, which leads to a striking regression of androgen-responsive cancer cells. A transition from an androgen-responsive to an androgen-unresponsive stage is seen during the clinical course in almost all patients with prostate cancer. This transition also signals a substantial worsening of prognosis. Here, we review the most important findings in prostate carcinogenesis and the molecular anomalies associated with the androgen-refractory stage.

Environmental Exposure↗
PubMed2002

Androgen receptor CAG repeats and prostate cancer.

Prostate cancer is the most common nonskin malignancy and the second leading cause of cancer deaths among men in the United States. Prostate cancer ([Mendelian Inheritance in Man 176807]) has a complex etiology; presently, age, ethnicity, and family history are the most consistently reported risk factors associated with disease. Other potential risk and protective factors have also been suggested. Androgen, acting through the androgen receptor (AR) is helpful in preserving the normal function and structure of the prostate. The AR ([Mendelian Inheritance in Man 313700]) is a structurally conserved member of the nuclear receptor superfamily of ligand-activated transcription factors. Androgens, such as testosterone, are strong tumor promoters, and work with the AR to augment the effect of any carcinogens present and stimulate cell division. The CAG repeats encode long glutamine homopolymeric amino acid chains in the amino-terminal domain of the AR gene. The authors focus on CAG repeat length because recent research suggests that men with shorter AR CAG lengths (e.g., < or =22 repeats) are at a greater risk of developing prostate cancer than are those with longer variants. Among populations studied to date, African Americans appear to have the highest frequency of short CAG repeats. Several potential interactions have also been explored, including molecular interactions, androgen deprivation therapy, and prostate-specific antigen expression. CAG repeat length can be determined with high sensitivity and specificity. Presently, there is no recommended population screening for AR CAG repeat length.

Aged↗