Circulating microRNAs as potential new biomarkers for prostate cancer.

Since they were first described in the 1990s, circulating microRNAs (miRNAs) have provided an active and rapidly evolving area of current research that has the potential to transform cancer diagnostics and therapeutics. In particular, miRNAs could provide potential new biomarkers for prostate cancer, the most common cause of cancer in UK men. Current diagnostic tests for prostate cancer have low specificity and poor sensitivity. Further, although many prostate cancers are so slow growing as not to pose a major risk to health, there is currently no test to distinguish between these and cancers that will become aggressive and life threatening. Circulating miRNAs are highly stable and are both detectable and quantifiable in a range of accessible bio fluids, thus have the potential to be useful diagnostic, prognostic and predictive biomarkers. This review aims to summarise the current understanding of circulating miRNAs in prostate cancer patients and their potential role as biomarkers.

Endo180 modulation by bisphosphonates and diagnostic accuracy in metastatic breast cancer.

BACKGROUND: Endo180 (CD280; MRC2; uPARAP)-dependent collagen remodelling is dysregulated in primary tumours and bone metastasis. Here, we confirm the release and diagnostic accuracy of soluble Endo180 for diagnosing metastasis in breast cancer (BCa). METHODS: Endo180 was quantified in BCa cell conditioned medium and plasma from BCa patients stratified according to disease status and bisphosphonate treatment (n=88). All P-values are from two-sided tests. RESULTS: Endo180 is released by ectodomain shedding from the surface of MCF-7 and MDA-MB-231 BCa cell lines. Plasma Endo180 was significantly higher in recurrent/metastatic (1.71±0.87; n=59) vs early/localised (0.92±0.37; n=29) BCa (P<0.0001). True/false-positive rates for metastasis classification were: 85%/50% for the reference standard, CA 15-3 antigen (28 U ml(-1)); ≤97%/≥36% for Endo180; and ≤97%/≥32% for CA 15-3 antigen+Endo180. Bisphosphonate treatment was associated with reduced Endo180 levels in BCa patients with bone metastasis (P=0.011; n=42). True/false-positive rates in bisphosphonate-naive patients (n=57) were: 68%/45% for CA 15-3 antigen; ≤95%/≥20% for Endo180; and ≤92%/≥21% for CA 15-3 antigen+Endo180. CONCLUSION: Endo180 is a potential marker modulated by bisphosphonates in metastatic BCa.

Current management of prostate cancer: dilemmas and trials.

The past decade has witnessed significant advances in our understanding of the biology of prostate cancer. Androgen ablation/androgen receptor inhibition remains as the mainstay of treatment for advanced prostate cancer. Our understanding of the biology of prostate cancer has increased exponentially owing to advances in molecular biology. With this knowledge many intriguing issues have come to light, which clinicians and scientists alike strive to answer. These include why prostate cancer is so common, what drives the development of prostate cancer at a molecular level, why prostate cancer appears refractory to many families of cytotoxic chemotherapeutics, and why prostate cancer preferentially metastasizes to bone. Two clinical forms of prostate cancer have been identified: indolent organ confined disease, which elderly men often die of, and aggressive metastatic disease. A method of distinguishing between these two forms of the disease at an organ-confined stage remains elusive. Understanding the mechanisms of castrate resistance is a further issue of clinical importance. New trials of treatments, including molecular agents that target prostate cancer from a range of angles, have been instituted over the past 10-15 years. We can look at these trials not only as a chance to investigate the effectiveness of new treatments but also as an opportunity to further understand the complex biology of this disease.

Advances in the treatment of pancreatic neuroendocrine tumours.

Pancreatic neuroendocrine tumours (pNETs) are relatively rare and generally felt to follow an indolent course. But poorly differentiated tumours can behave aggressively with 5-year survival ranging from 31% to 48%. Recent data suggest that patients with pNETs may derive benefit from treatment targeting the molecular changes expressed in this tumour group. This article describes advances in the treatment of unresectable pNETs that have led to a doubling of progression free survival.

Circulating sphingosine-1-phosphate and erythrocyte sphingosine kinase-1 activity as novel biomarkers for early prostate cancer detection.

BACKGROUND: Current markers available for screening normal populations and for monitoring prostate cancer (PCa) treatment lack sensitivity and selectivity. Sphingosine-1-phosphate (S1P) is a circulating lipid second messenger involved in cell growth and migration, the immune response, angiogenesis, and malignant transformation. METHODS: Eighty-eight patients with localised, locally advanced, or metastatic PCa were recruited into this prospective single-centre study. Plasma S1P levels were measured and compared with age-matched controls with benign prostate hyperplasia (BPH) (n=110) or with young healthy males with the very small chance of having PCa foci (n=20). RESULTS: Levels of circulating S1P were significantly higher in healthy subjects (10.36 ± 0.69 pmol per mg protein, P<0.0001) and patients with BPH (9.39 ± 0.75, P=0.0013) than in patients with PCa (6.89 ± 0.58, ANOVA, P=0.0019). Circulating S1P levels were an early marker of PCa progression to hormonal unresponsiveness and correlated with prostate-specific antigen (PSA) levels and lymph node metastasis. During the course of the study, nine patients have died of PCa. Importantly, their circulating S1P levels were significantly lower (5.11 ± 0.75) than in the surviving patients (7.02 ± 0.22, n=79, P=0.0439). Our data suggest that the decrease in circulating S1P during PCa progression may stem from a highly significant downregulation of erythrocyte sphingosine kinase-1 (SphK1) activity (2.14 ± 0.17 pmol per mg protein per minute in PCa patients vs 4.7 ± 0.42 in healthy individuals, P<0.0001), which may be a potential mechanism of cancer-induced anaemia. CONCLUSION: This current study has provided a potential mechanism for cancer-related anaemia and the first evidence that plasma S1P and erythrocyte SphK1 activity are the potential markers for the diagnosis, monitoring, and predicating for PCa mortality.

Reducing prohibitin increases histone acetylation, and promotes androgen independence in prostate tumours by increasing androgen receptor activation by adrenal androgens.

Prostate cancers (PCs), initially responsive to anti-androgen therapies, often advance to a hormone-refractory 'castrate-resistant' PC (CRPC) stage. However, the androgen receptor (AR) pathway remains active and key for cell growth and gene expression within tumours, even in the apparent absence of hormone. Proposed mechanisms to explain progression, including AR amplification/mutation, are insufficient to completely explain CRPC and possible roles of AR cofactors such as prohibitin (PHB) are poorly understood. We investigated whether PHB loss could sensitise PC cells and tumours to adrenal gland-derived androgens, which persist even after androgen ablation, hence contribute to development of CRPC. Using a pair of PC cell lines, inducibly expressing ectopic cDNA or RNAi for PHB, responses to different androgens and hormone concentrations were studied both in vitro and in vivo. PHB was found at the promoters of several genes, both AR and non-AR-regulated, and knockdown increased histone acetylation at these promoters. Further, PHB knockdown increased the rate of AR ligand-induced chromatin binding, and binding rate and occupancy of AR upon the PSA promoter. This resulted in increased cell growth and AR activity in response to all androgens, including promoting a response to the weaker adrenal androgens previously absent at physiological concentrations. In vivo this had functional consequences such that PHB knockdown resulted in androstenedione being sufficient to promote tumour growth, under conditions mimicking those in patients undergoing androgen ablation therapy. We conclude that reduction in PHB levels is sufficient to lower the threshold of AR activity in vitro and in vivo; this may be via a general increase in histone acetylation that could potentially affect signalling by other transcription factors. PHB loss may provide a mechanism for progression to CRPC by sensitising PC cells to 'castrate' conditions-that is, low levels of testicular androgens in the continued presence of weak adrenal and dietary androgens.

The experiences of cancer patients.

OBJECTIVES: To assess the needs of cancer patients for information about their condition and to understand the psychological impact of their illness. BACKGROUND: The discussion of prognosis and treatment options in the palliative setting is an important and difficult part of oncology practice. To evaluate this, we examined the experiences of cancer patients of the physical and psychological impact of their disease on their life, and their opinions on the communication of end-of-life decisions and treatment options. METHODS: A patient questionnaire was designed that encompassed communication regarding treatment and prognosis, quality-of-life attitudes subsequent to cancer diagnosis, end-of-life care and cancer drug funding. One hundred and twenty-five patients with a diagnosis of cancer were asked to participate and 96 questionnaires were completed and available for analysis. The questionnaire consisted of 63 questions and was completed in both an inpatient and outpatient setting. RESULTS: This survey brought to light a number of controversial issues in cancer service provision, highlighting the emotional and psychological changes brought about by a cancer diagnosis. Major concerns of our patients include fear of death and pain, changes in interpersonal relationships and financial constraints. Only 66% of the patients wanted to be given a prognosis by their clinicians and just 70% of the patients recalled being given a detailed prognosis. 11% of the patients were not prepared to undergo palliative treatment. In all, 7% were not prepared to accept treatment for 1 year and 2% for 5 years of life in exchange for the potential side effects of cytotoxic chemotherapy. 12% of the patients would not want to be in possession of the information that they were in the terminal phase of the illness with a short time to live and 16% would not want this discussed with their next of kin. CONCLUSION: This study informs medical professionals about the importance of tailoring information to the needs of the individual patient, and we feel it provides insights into the successes and failures of our communication with cancer patients. It is important that difficult discussions are personalized to the individual patients' wishes. These can vary dramatically both in the area of disclosure of bad news in prognosis and in end-of-life decision making. This study provides compelling evidence for good advanced care planning at an early stage in the management of patients with terminal cancers.

Langerhans cell histiocytosis: old disease new treatment.

Langerhans cell histiocytosis (LCH) has been previously thought of as a rare illness, but is now increasingly diagnosed as a result of the more intensive investigations of patients with cystic pulmonary disease. In recent years, treatments developed from our new understanding of the molecular biology of malignant disease have been applied to patients with LCH, and responses seen. In this review, we describe the origins, presentation and modern treatment of LCH, showing that there is new hope for patients with this condition.

Inflammatory cytokines and aromatase inhibitor-associated musculoskeletal syndrome: a case-control study.

BACKGROUND: The aromatase inhibitor (AI)-associated musculoskeletal syndrome (AIMSS) occurs in approximately 50% of AI-treated patients. Inflammatory mediators are associated with oestrogen signalling and may change with oestrogen depletion. We hypothesised that AIMSS may be associated with changes in circulating inflammatory markers. METHODS: Patients with breast cancer were enrolled in a trial of adjuvant AI therapy. Changes in pain and function during therapy were assessed prospectively. We selected 30 cases with AIMSS and 22 controls without AIMSS, matched for demographics and prior therapy. Serum samples collected at baseline and during treatment were assayed for multiple inflammatory cytokines and lipid mediators using multiplex assays. RESULTS: Before AI therapy, mean serum concentrations of 6 of 36 assayed factors were statistically significantly lower in cases than controls (all P<0.003). No statistically significant changes during AI therapy relative to pre-treatment were observed between cases and controls for any of the inflammatory markers tested. CONCLUSION: AIMSS is probably not associated with a systemic inflammatory response. Pre-treatment cytokine levels may predict for development of AIMSS.

The cost of a QALY.

BACKGROUND: Current regulation of drug approvals has caused considerable controversy as entrusted to the National Institute of Clinical Excellence, and has led to a lack of availability of modern medicines on the basis of calculations made of 'value'. AIM: We have examined the assessment tool used by National Institute of Clinical Excellence (NICE) to establish the cost of drugs in order to assess whether it is a reasonable and objective evaluation methodology. DESIGN: A review of the methods of analysis. METHODS: An objective assessment of the value of the Quality Adjusted Life Year (QALY). RESULTS: We conclude that current methods used by NICE to assess drug costs are arbitrary, subjective and fail to reflect the true costs for patients, which are grossly overestimated. CONCLUSION: NICE needs to look again at the evaluation methods for calculating drug costs, and change their methodology from a subjective to an objective measure of true cost.

Dhrs3a regulates retinoic acid biosynthesis through a feedback inhibition mechanism.

Retinoic acid (RA) is an important developmental signaling molecule responsible for the patterning of multiple vertebrate tissues. RA is also a potent teratogen, causing multi-organ birth defects in humans. Endogenous RA levels must therefore be tightly controlled in the developing embryo. We used a microarray approach to identify genes that function as negative feedback regulators of retinoic acid signaling. We screened for genes expressed in early somite-stage embryos that respond oppositely to treatment with RA versus RA antagonists and validated them by RNA in situ hybridization. Focusing on genes known to be involved in RA metabolism, we determined that dhrs3a, which encodes a member of the short-chain dehydrogenase/reductase protein family, is both RA dependent and strongly RA inducible. Dhrs3a is known to catalyze the reduction of the RA precursor all-trans retinaldehyde to vitamin A; however, a developmental function has not been demonstrated. Using morpholino knockdown and mRNA over-expression, we demonstrate that Dhrs3a is required to limit RA levels in the embryo, primarily within the central nervous system. Dhrs3a is thus an RA-induced feedback inhibitor of RA biosynthesis. We conclude that retinaldehyde availability is an important level at which RA biosynthesis is regulated in vertebrate embryos.

Microarray coupled to quantitative RT-PCR analysis of androgen-regulated genes in human LNCaP prostate cancer cells.

The androgen receptor (AR) mediates the growth-stimulatory effects of androgens in prostate cancer cells. Identification of androgen-regulated genes in prostate cancer cells is therefore of considerable importance for defining the mechanisms of prostate-cancer development and progression. Although several studies have used microarrays to identify AR-regulated genes in prostate cancer cell lines and in prostate tumours, we present here the results of gene expression microarray profiling of the androgen-responsive LNCaP prostate-cancer cell line treated with R1881 for the identification of androgen-regulated genes. We show that the expression of 319 genes is stimulated by 24 h after R1881 addition, with a similar number (300) of genes being significantly repressed. Expression of the upregulated genes, as well as of 60 of the most robustly downregulated genes, was carried out using quantitative RT-PCR (Q-RT-PCR) over a time-course of R1881 treatment from 0 to 72 h. Q-RT-PCR was also carried out following treatment with other AR agonists (dihydrotestosterone, estradiol and medroxyprogesterone) and antagonists (cyproterone acetate, hydroxyflutamide and bicalutamide). This study provides a comprehensive analysis of androgen-regulated gene expression in the LNCaP prostate cancer cell line, and identifies a number of androgen-regulated genes, not described previously, as candidates for mediating androgen responses in prostate cancer cells.

Voodoo dolls and the cancer patient: patients do trust their doctors.

OBJECTIVES: To determine oncology patients' pattern and rationale of complementary and alternative medicine (CAM) use, and canvass their views on the relative merits of allopathic and alternative medicine. DESIGN: Observational study of opinions from a cohort of patients using self-completion questionnaires. SETTING: Oncology departments of two UK teaching hospitals. PARTICIPANTS: Voluntary participation of 200 oncology patients attending clinic. MAIN FINDINGS: Twenty-two percent of patients used CAM, with a preponderance towards younger, female patients. The commonest reasons for CAM use is to make the patient feel better and to help with their cancer. However, patients seldom believe there is more evidence for CAM or that CAM will cure them, indeed often noticing no benefits from the treatment. CAM users do not resort to complementary medicine due to dissatisfaction with their doctor but instead have considerable trust in their physicians. Only a minority believes their doctor knows about their CAM use. CONCLUSION: CAM use by oncology patients in the UK is less common than that reported elsewhere. Although patients try CAM in the hope that it will help with their treatment, they are realistic about its likely benefits. It uptake is not as an indication of lack of faith in doctors, yet physicians are frequently unaware of use. Therefore, the medical profession should not feel threatened by patients resorting to CAM but instead focus on understanding the reasons behind it.

Secreted Frizzled-related protein-1 is a negative regulator of androgen receptor activity in prostate cancer.

Secreted Frizzled-related protein-1 (sFRP1) associates with Wnt proteins and its loss can lead to activation of Wnt/beta-catenin signalling. It is frequently downregulated in cancer, including prostate cancer, but its function in prostate cancer is unclear because it can increase proliferation of prostate epithelial cells. We investigated the function of sFRP1 in androgen-dependent prostate cancer and found that sFRP1 inhibited androgen receptor (AR) transcriptional activity. In addition, sFRP1 inhibited the proliferation of androgen-dependent LNCaP cells but not of an androgen-independent subline LNCaP-r, suggesting a role in androgen-dependent growth. The inhibition of AR by sFRP1 was unaffected by co-expression of Wnt3a, stabilised beta-catenin or beta-catenin shRNA, suggesting it does not involve Wnt/beta-catenin signalling. Wnt5a also inhibited AR and expression of Wnt5a and sFRP1 together did not further inhibit AR, suggesting that Wnt5a and sFRP1 activate the same signal(s) to inhibit AR. However, sFRP1 inhibition of AR was unaffected by inhibitors of kinases involved in Wnt/Ca(2+) and Wnt/planar cell polarity non-canonical Wnt signalling. Interestingly, the cysteine-rich domain of sFRP1 interacted with Frizzled receptors expressed in prostate cancer cells, suggesting that sFRP1/Frizzled complexes activate a signal that leads to repression of AR. Taken together, these observations highlight the function of beta-catenin-independent Wnt signalling in the control of AR activity and provide one explanation for sFRP1 downregulation in prostate cancer.

Advances in tumour immunotherapy.

The clinical goal of tumour immunotherapy is to provide either active or passive immunity against malignancies by harnessing the immune system to target tumours. Although vaccination is an effective strategy to prevent infectious disease, it is less effective in the therapeutic setting for cancer treatment, which might be related to the low immunogenicity of tumour antigens and the reduced immunocompetence of cancer patients. Recent advances in technology have led to the development of passive immunotherapy approaches that utilize the unique specificity of antibodies and T cell receptors to target selected antigens on tumour cells. These approaches are likely to benefit patients and alter the way that clinicians treat malignant disease. In this article we review recent advances in the immunotherapy of cancer, focusing on new strategies to enhance the efficacy of passive immunotherapy with monoclonal antibodies and antigen-specific T cells.

Prohibitin, a protein downregulated by androgens, represses androgen receptor activity.

Prohibitin (PHB) is a cell cycle regulatory protein, known to repress E2F1-mediated gene activation via recruitment of transcriptional regulatory factors such as retinoblastoma and histone deacetylase 1 (HDAC1). We previously identified PHB as a target protein of androgen signaling in prostate cancer cells and showed that downregulation of PHB is required for androgen-induced cell cycle entry in these cells. We now present evidence that PHB, which has 54% homology at the protein level to the oestrogen receptor corepressor REA (repressor of oestrogen receptor activity), can repress androgen receptor (AR)-mediated transcription and androgen-dependent cell growth. Depletion of endogenous PHB resulted in an increase in expression of the androgen-regulated prostate-specific antigen gene. The repression appears to be specific to androgen and closely related receptors, as it is also evident for the glucocorticoid and progesterone, but not oestrogen, receptors. In spite of interaction of PHB with HDAC1, HDAC activity is not required for this repression. Although AR and PHB could be co-immunoprecipitated, no direct interaction was detectable, suggesting that PHB forms part of a repressive complex with the AR. Competition with the co-activator SRC1 further suggests that formation of a complex with AR, PHB and other cofactors is the mechanism by which repression is achieved. It appears then that repression of AR activity is one mechanism by which PHB inhibits androgen-dependent growth of prostate cells. Further, this study implies that the AR itself could, by mediating downregulation of a corepressor, be involved in the progression of prostate tumours to the hormone refractory stage.

Regulation of prostate cell growth and morphogenesis by Dickkopf-3.

Wnt signalling plays a critical role in the development of cancer. Recent studies indicate that Wnt signalling is negatively regulated by secreted Wnt antagonists such as secreted frizzled related proteins (sFRPs) and Dickkopfs (Dkks). We compared Dkk family expression levels in normal prostate and prostate cancer cells and found a reduction in Dkk-3 expression in cancer cells. Ectopic expression of Dkk-3 inhibited colony formation in LNCaP and PC3 prostate cancer cell lines and inducible expression of Dkk-3 reduced LNCaP cell proliferation. Moreover, small interfering RNA-mediated downregulation of Dkk-3 enhanced cell cycle progression in untransformed RWPE-1 prostate epithelial cells. Immunohistochemical analysis revealed that Dkk-3 is expressed in a subset of normal prostate gland acini and that Dkk-3 expression is reduced in prostate tumours, particularly those with a high Gleason grade, suggesting a role for Dkk-3 in postmitotic differentiation. Consistent with this, depletion of Dkk-3 disrupted acinar morphogenesis of RWPE-1 cells in a three-dimensional cell culture model. Our results are consistent with the loss of Dkk-3 expression resulting in impairment of glandular structure and uncontrolled prostate epithelial cell (PrEC) proliferation, both of which are crucial for prostate cancer progression.