The occurrence and associated risk factors of brain metastases in well differentiated grade 1 and 2 bronchial neuroendocrine tumours: A single centre retrospective analysis of 280 patients.

Typical and atypical bronchial carcinoid account for around 2% of all neuroendocrine neoplasms of pulmonary origin. Fewer than 5% of patients with these cancers are thought to develop brain metastases, and hence routine intracranial imaging is not currently included in staging investigations. In this study, retrospective case note analysis was performed on 280 patients diagnosed with either typical carcinoid (TC) or atypical carcinoid (AC) at a large, single-site cancer centre. None of the 219 patients with TC developed brain metastases during the course of their disease, whereas seven of the 61 AC (11.5%) were found to have intracranial spread, four of which were present at the point of diagnosis. A Cox proportional hazard model showed that a Ki-67 expression ≥18%, patient age ≥65 years and disease stage at diagnosis were all independently and significantly associated with the development of brain metastases in AC. This study has found new evidence that the incidence of brain metastases in AC is significantly higher than previously thought. Of all the variables reviewed, Ki-67 expression was most strongly associated with the development of intracranial disease in AC and could be readily translated into clinical practice. Predictive factors such as age, disease stage and Ki-67 expression could be used to identify patients at particularly increased risk of brain metastases, who would benefit from early intracranial imaging. This could allow for earlier detection and treatment of metastases, with the potential to improve clinical outcomes and patient quality of life.

Nutlin-3 inhibits androgen receptor-driven c-FLIP expression, resulting in apoptosis of prostate cancer cells.

Inhibition of androgen receptor (AR) signalling represents the conventional medical management of prostate cancer. Ultimately this treatment fails because tumors develop an incurable, castrate resistant phenotype, resulting in an unmet need for new treatments in prostate cancer. The AR remains a viable therapeutic target in castrate resistant disease, such that novel ways of downregulating AR activities are attractive as potential treatments. Here we describe a mechanism by which the AR can be downregulated by the MDM2 antagonist Nutlin-3, resulting in loss of pro-survival c-FLIP gene expression and apoptosis. We additionally show that loss of c-FLIP sensitises prostate cancer cells to Nutlin-3. Finally, we demonstrate that the unrelated MDM2 antagonist Mi-63 also impinges upon AR signalling, supporting the concept of future treatment of prostate cancer with MDM2 antagonists.

AZD3514: a small molecule that modulates androgen receptor signaling and function in vitro and in vivo.

Continued androgen receptor (AR) expression and signaling is a key driver in castration-resistant prostate cancer (CRPC) after classical androgen ablation therapies have failed, and therefore remains a target for the treatment of progressive disease. Here, we describe the biological characterization of AZD3514, an orally bioavailable drug that inhibits androgen-dependent and -independent AR signaling. AZD3514 modulates AR signaling through two distinct mechanisms, an inhibition of ligand-driven nuclear translocation of AR and a downregulation of receptor levels, both of which were observed in vitro and in vivo. AZD3514 inhibited testosterone-driven seminal vesicle development in juvenile male rats and the growth of androgen-dependent Dunning R3327H prostate tumors in adult rats. Furthermore, this class of compound showed antitumor activity in the HID28 mouse model of CRPC in vivo. AZD3514 is currently in phase I clinical evaluation.

Androgen receptor expression is a biological marker for androgen sensitivity in high grade serous epithelial ovarian cancer.

OBJECTIVES: In the present study we explore the effects of androgens and anti-androgens on primary cultures of EOC cells. We also investigate the effects of chemotherapy on AR expression. Epithelial ovarian cancer (EOC) arises from ovarian surface epithelial cells (OSE), which express the androgen receptor (AR). Androgen stimulation of OSE cells results in increased proliferation and protection from apoptosis. Nevertheless, in clinical trials anti-androgens have had a low objective response rate in relapsed ovarian cancer. METHODS: 1. Androgen receptor (AR) expression and response to androgenic stimulation were correlated in primary ovarian cancer cells derived from ascitic fluid from patients with advanced ovarian cancer, 2. AR expression in primary epithelial ovarian cancer was investigated before and after chemotherapy using paired histological samples which had been incorporated into a tissue microarray. RESULTS: Eleven primary ovarian cancer cultures were established from ascitic fluid. There was wide variation of expression of androgen receptor mRNA between cultures. Cell division increased after dihydro-testosterone (DHT) stimulation in 6 out of 11 primary cultures. The fraction of cells in S-phase increased from 4.4% in cells grown in serum-free medium to 8.3% in cells stimulated with 100 nM of DHT (P<0.001). The increase in S-phase fraction was abrogated after treatment with the anti-androgen, bicalutamide in 4 out of 5 responsive cultures. There was a strong correlation (r(2)=0.7) between nuclear AR expression by immunohistochemistry and S-phase fraction changes in primary cultures. Paired pre- and post-chemotherapy histological samples from 29 patients were incorporated into a tissue microarray (TMA). Nuclear and cytoplasmic AR expression by immunohistochemistry (IHC) decreased significantly after chemotherapy (P<0.01). CONCLUSION: AR expression correlates with increased S-phase fraction in response to androgenic stimulation. Immunohistochemical analysis of AR expression needs to be further tested in clinical trials to select AR positive EOC for anti-androgen therapy. Anti-androgen use early in the course of ovarian cancer is more likely to be effective as these data suggest that androgen receptor expression decreases with exposure to chemotherapy and this may explain the low response rates seen in clinical trials of patients heavily pre-treated with multiple courses of chemotherapy.

Targeting the DNA double strand break repair machinery in prostate cancer.

Regardless of the achievable remissions with first line hormone therapy in patients with prostate cancer (CaP), the disease escapes the hormone dependent stage to a more aggressive status where chemotherapy is the only effective treatment and no treatment is curative. This makes it very important to identify new targets that can improve the outcome of treatment. ATM and DNA-PK are the two kinases responsible for signalling and repairing double strand breaks (DSB). Thus, both kinases are pertinent targets in CaP treatment to enhance the activity of the numerous DNA DSB inducing agents used in CaP treatment such as ionizing radiation (IR). Colony formation assay was used to assess the sensitivity of hormone dependent, p53 wt (LNCaP) and hormone independent p53 mutant (PC3) CaP cell lines to the cytotoxic effect of IR and Doxorubicin in the presence or absence of Ku55933 and NU7441 which are small molecule inhibitors of ATM and DNA-PK, respectively. Flow cytometry based methods were used to assess the effect of the two inhibitors on cell cycle, apoptosis and H2AX foci formation. Neutral comet assay was used to assess the induction of DNA DSBs. Ku55933 or NU7441 alone increased the sensitivity of CaP cell lines to the DNA damaging agents, however combining both inhibitors together resulted in further enhancement of sensitivity. The cell cycle profile of both cell lines was altered with increased cell death, DNA DSBs and H2AX foci formation. This study justifies further evaluation of the ATM and DNA-PK inhibitors for clinical application in CaP patients. Additionally, the augmented effect resulting from combining both inhibitors may have a significant implication for the treatment of CaP patients who have a defect in one of the two DSB repair pathways.

Regulation of the androgen receptor by SET9-mediated methylation.

The androgen receptor (AR) is a member of the nuclear hormone receptor family of transcription factors that plays a critical role in regulating expression of genes involved in prostate development and transformation. Upon hormone binding, the AR associates with numerous co-regulator proteins that regulate the activation status of target genes via flux to the post-translational modification status of histones and the receptor. Here we show that the AR interacts with and is directly methylated by the histone methyltransferase enzyme SET9. Methylation of the AR on lysine 632 is necessary for enhancing transcriptional activity of the receptor by facilitating both inter-domain communication between the N- and C-termini and recruitment to androgen-target genes. We also show that SET9 is pro-proliferative and anti-apoptotic in prostate cancer cells and demonstrates up-regulated nuclear expression in prostate cancer tissue. In all, our date indicate a new mechanism of AR regulation that may be therapeutically exploitable for prostate cancer treatment.