Ian Vela

Prostate cancer biomarkers: Are we hitting the mark?

Purpose Localised prostate cancer diagnosis and management is increasingly complex due to its heterogeneous progression and prognostic subgroups. Pitfalls in current screening and diagnosis have prompted the search for accurate and invasive molecular and genetic biomarkers for prostate cancer. Such tools may be able to distinguish clinically significant cancers from less aggressive variants to assist with prostate cancer risk stratification and guide decisions and healthcare algorithms. We aimed to provide a comprehensive review of the current prostate cancer biomarkers available and in development. Methods MEDLINE and EMBASE databases searches were conducted to identify articles pertaining to the use of novel biomarkers for prostate cancer. Results A growing number of novel biomarkers are currently under investigation. Such markers include urinary biomarkers, serology-based markers or pathological tissue assessments of molecular and genetic markers. While limited clinical data is present for analysis, early results appear promising. Specifically, a combination of serum and urinary biomarkers (Serum PSA + Urinary PCA3 + Urinary TMPRSS2-ERG fusion) appears to provide superior sensitivity and specificity profiles compared to traditional diagnostic approaches (AUC 0.88). Conclusion The accurate diagnosis and risk stratification of prostate cancer is critical to ensure appropriate intervention. The development of non-invasive biomarkers can add to the information provided by current screening practices and allows for individualised risk stratification of patients. The use of these biomarkers appears to increase the sensitivity and specificity of diagnosis of prostate cancer. Further studies are necessary to define the appropriate use and time points of each biomarker and their effect on the management algorithm of prostate cancer.

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.

Exercise improves quality of life in androgen deprivation therapy-treated prostate cancer: systematic review of randomised controlled trials

Men receiving androgen deprivation therapy (ADT) for prostate cancer (PCa) are likely to develop metabolic conditions such as diabetes, cardiovascular disease, abdominal obesity and osteoporosis. Other treatment-related side effects adversely influence quality of life (QoL) including vasomotor distress, depression, anxiety, mood swings, poor sleep quality and compromised sexual function. The objective of this study was to systematically review the nature and effects of dietary and exercise interventions on QoL, androgen deprivation symptoms and metabolic risk factors in men with PCa undergoing ADT. An electronic search of CINAHL, CENTRAL, Medline, PsychINFO and reference lists was performed to identify peer-reviewed articles published between January 2004 and December 2014 in English. Eligible study designs included randomised controlled trials (RCTs) with pre- and post-intervention data. Data extraction and assessment of methodological quality with the Cochrane approach was conducted by two independent reviewers. Seven exercise studies were identified. Exercise significantly improved QoL, but showed no effect on metabolic risk factors (weight, waist circumference, lean or fat mass, blood pressure and lipid profile). Two dietary studies were identified, both of which tested soy supplements. Soy supplementation did not improve any outcomes. No dietary counselling studies were identified. No studies evaluated androgen-deficiency symptoms (libido, erectile function, sleep quality, mood swings, depression, anxiety and bone mineral density). Evidence from RCTs indicates that exercise enhances health- and disease-specific QoL in men with PCa undergoing ADT. Further studies are required to evaluate the effect of exercise and dietary interventions on QoL, androgen deprivation symptoms and metabolic risk factors in this cohort.

Short term ex-vivo expansion of circulating head and neck tumour cells

Minimally invasive techniques are required for the identification of head and neck cancer (HNC) patients who are at an increased risk of metastasis, or are not responding to therapy. An approach utilised in other solid cancers is the identification and enumeration of circulating tumour cells (CTCs) in the peripheral blood of patients. Low numbers of CTCs has been a limiting factor in the HNC field to date. Here we present a methodology to expand HNC patient derived CTCs ex-vivo. As a proof of principle study, 25 advanced stage HNC patient bloods were enriched for circulating tumour cells through negative selection and cultured in 2D and 3D culture environments under hypoxic conditions (2% O2, 5% CO2). CTCs were detected in 14/25 (56%) of patients (ranging from 1–15 CTCs/5 mL blood). Short term CTC cultures were successfully generated in 7/25 advanced stage HNC patients (5/7 of these cultures were from HPV+ patients). Blood samples from which CTC culture was successful had higher CTC counts (p = 0.0002), and were predominantly from HPV+ patients (p = 0.007). This is, to our knowledge, the first pilot study to culture HNC CTCs ex-vivo. Further studies are warranted to determine the use of short term expansion in HNC and the role of HPV in promoting culture success.

Metabolic Syndrome and Prostate Cancer: a Review of Complex Interplay Amongst Various Endocrine Factors in the Pathophysiology and Progression of Prostate Cancer

The human prostate gland is an endocrine organ where dysregulation of various hormonal factors may play a pivotal role in the pathogenesis of prostate cancer. There is emerging epidemiological data to support the role of components of metabolic syndrome, namely, obesity, hypercholesterolaemia, diabetes and hyperinsulinaemia on the development and/or the progression of prostate cancer. Although the exact mechanisms behind the relationship between metabolic syndrome and prostate cancer remain largely unknown, various in vitro and animal experiments of metabolic syndrome models have been shown to promote survival, mitogenesis, metastasis and treatment resistance pathways, through various adaptive responses such as intracellular steroidogenesis and lipogenesis. Also, in a large proportion of men with metabolic syndrome, alteration in levels of hormones such as testosterone, leptin and adiponectin has been shown to contribute towards the aggression of prostate cancer. Whilst the exact bio-pathophysiological mechanisms between metabolic syndrome and prostate cancer are yet to be fully elucidated, medications that target specific components of metabolic syndrome have further provided evidence for the inter-relationship between metabolic syndrome, its components and prostate cancer. Emerging in vitro and molecular data is likely to bring us closer to utilizing this knowledge to target particular cancer survival pathways and improving outcomes for men with prostate cancer.

Prostate cancer organoids: a potential new tool for testing drug sensitivity

Recent technical advances have enabled for the first time, reliable in vitro culture of prostate cancer samples as prostate cancer organoids. This breakthrough provides the significant possibility of high throughput drug screening covering the spectrum of prostate cancer phenotypes seen clinically. These advances will enable precision medicine to become a reality, allowing patient samples to be screened for effective therapeutics ex vivo, with tailoring of treatments specific to that individual. This will hopefully lead to enhanced clinical outcomes, avoid morbidity due to ineffective therapies and improve the quality of life in men with advanced prostate cancer.

Using prostate specific membrane antigen (PSMA) expression in clear cell renal cell carcinoma for imaging advanced disease

Prostate specific membrane antigen (PSMA) is a 750 amino acid, type II transmembrane glycoprotein that has been shown to be over-expressed in both prostate cancer cells and the vasculature of solid tumours.1 Also known as folate dehydrolase, glutamate carboxypeptidase II or N-acetyl-L-aspartyl-L-glutamate peptidase I,2 PSMA has numerous metabolic roles and high levels of expression have been associated with tumour aggressiveness and malignant potential of prostate cancer cells...

Molecular Profiles of Prostate Cancer: To Treat or Not to Treat.

A major dilemma in the selection of treatment for men with prostate cancer is the difficulty in accurately characterizing the risk posed by the cancer. This uncertainty has led physicians to recommend aggressive therapy for most men diagnosed with prostate cancer and has led to concerns about the benefits of screening and the adverse consequences of excessive treatment. Genomic analyses of prostate cancer reveal distinct patterns of alterations in the genomic landscape of the disease that show promise for improved prediction of prognosis and better medical decision making. Several molecular profiles are now commercially available and are being used to inform medical decisions. This article describes the clinical tests available for distinguishing aggressive from nonaggressive prostate cancer, reviews the new genomic tests, and discusses their advantages and limitations and the evidence for their utility in various clinical settings.

PITX2 and non-canonical Wnt pathway interaction in metastatic prostate cancer

AbstractThe non-canonical Wnt pathway, a regulator of cellular motility and morphology, is increasingly implicated in cancer metastasis. In a quantitative PCR array analysis of 84 Wnt pathway associated genes, both non-canonical and canonical pathways were activated in primary and metastatic tumors relative to normal prostate. Expression of the Wnt target gene PITX2 in a prostate cancer (PCa) bone metastasis was strikingly elevated over normal prostate (over 2,000-fold) and primary prostate cancer (over 200-fold). The elevation of PITX2 protein was also evident on tissue microarrays, with strong PITX2 immunostaining in PCa skeletal and, to a lesser degree, soft tissue metastases. PITX2 is associated with cell migration during normal tissue morphogenesis. In our studies, overexpression of individual PITX2A/B/C isoforms stimulated PC-3 PCa cell motility, with the PITX2A isoform imparting a specific motility advantage in the presence of non-canonical Wnt5a stimulation. Furthermore, PITX2 specific shRNA inhibited PC-3 cell migration toward bone cell derived chemoattractant. These experimental results support a pivotal role of PITX2A and non-canonical Wnt signaling in enhancement of PCa cell motility, suggest PITX2 involvement in homing of PCa to the skeleton, and are consistent with a role for PITX2 in PCa metastasis to soft and bone tissues. Our findings, which significantly expand previous evidence that PITX2 is associated with risk of PCa biochemical recurrence, indicate that variation in PITX2 expression accompanies and may promote prostate tumor progression and metastasis.

Imaging tumour thrombus of clear cell renal cell carcinoma: FDG PET or PSMA PET? Direct in vivo comparison of two technologies

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal malignancy in adults.1 The disease is usually radiologically imaged with computed tomography (CT) or magnetic resonance imaging (MRI) for diagnosis, staging, treatment planning and follow up. Recently, functional studies targeting glucose or folate metabolism with fludeoxyglucose (FDG) or prostate specific membrane antigen (PSMA) binding ligands respectively have been reported to be used to stage the disease.2 Positron emission tomography (PET) using PSMA ligand detected larger number of lesions in comparison to conventional imaging modalities such as CT in a small prospective clinical trial.3 In this project, we directly compared the findings from FDG and PSMA PET in a patient with metastatic ccRCC. We assessed ex-vivo tumour characteristics to explain these findings.