The tumour hypoxia marker pimonidazole reflects a transcriptional programme associated with aggressive prostate cancer.

BACKGROUND: The hypoxia marker pimonidazole is a candidate biomarker of cancer aggressiveness. We investigated the transcriptional programme associated with pimonidazole staining in prostate cancer. METHODS: Index tumour biopsies were taken by image guidance from an investigation cohort of 52 patients, where 43 patients received pimonidazole before prostatectomy. Biopsy location within the index tumour was verified for 46 (88%) patients, who were included for gene expression profiling and immunohistochemistry. Two independent cohorts of 59 and 281 patients were used for validation. RESULTS: Expression of genes in proliferation, DNA repair and hypoxia response was a major part of the transcriptional programme associated with pimonidazole staining. A signature of 32 essential genes was constructed and showed positive correlation to Ki67 staining, confirming the increased proliferation in hypoxic tumours as suggested from the gene data. Positive correlations were also found to tumour stage and lymph node status, but not to blood prostate-specific antigen level, consistent with the findings for pimonidazole staining. The association with aggressiveness was confirmed in validation cohorts, where the signature correlated with Gleason score and had independent prognostic impact, respectively. CONCLUSIONS: Pimonidazole staining reflects an aggressive hypoxic phenotype of prostate cancer characterised by upregulation of proliferation, DNA repair and hypoxia response genes.

Androgen deprivation therapy: past, present and future.

Since Huggins and Hodges demonstrated the responsiveness of prostate cancer to androgen deprivation therapy (ADT), androgen-suppressing strategies have formed the cornerstone of management of advanced prostate cancer. Approaches to ADT have included orchidectomy, oestrogens, luteinizing hormone-releasing hormone (LHRH) agonists, anti-androgens and more recently the gonadotrophin-releasing hormone antagonists. The most extensively studied antagonist, degarelix, avoids the testosterone surge and clinical flare associated with LHRH agonists, offering more rapid PSA and testosterone suppression, improved testosterone control and improved PSA progression-free survival compared with agonists. The clinical profile of degarelix appears to make it a particularly suitable therapeutic option for certain subgroups of patients, including those with metastatic disease, high baseline PSA (>20 ng/mL) and highly symptomatic disease. As well as forming the mainstay of treatment for advanced prostate cancer, ADT is increasingly used in earlier disease stages. While data from clinical trials support the use of ADT neoadjuvant/adjuvant to radiotherapy for locally advanced or high-risk localized prostate cancer, it remains to be established whether specific ADT classes/agents provide particular benefits in this clinical setting.

Targeted prostate cancer screening in men with mutations in BRCA1 and BRCA2 detects aggressive prostate cancer: preliminary analysis of the results of the IMPACT study.

OBJECTIVE: To evaluate the role of targeted prostate cancer screening in men with BRCA1 or BRCA2 mutations, an international study, IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls), was established. This is the first multicentre screening study targeted at men with a known genetic predisposition to prostate cancer. A preliminary analysis of the data is reported. PATIENTS AND METHODS: Men aged 40-69 years from families with BRCA1 or BRCA2 mutations were offered annual prostate specific antigen (PSA) testing, and those with PSA > 3 ng/mL, were offered a prostate biopsy. Controls were men age-matched (± 5 years) who were negative for the familial mutation. RESULTS: In total, 300 men were recruited (205 mutation carriers; 89 BRCA1, 116 BRCA2 and 95 controls) over 33 months. At the baseline screen (year 1), 7.0% (21/300) underwent a prostate biopsy. Prostate cancer was diagnosed in ten individuals, a prevalence of 3.3%. The positive predictive value of PSA screening in this cohort was 47·6% (10/21). One prostate cancer was diagnosed at year 2. Of the 11 prostate cancers diagnosed, nine were in mutation carriers, two in controls, and eight were clinically significant. CONCLUSIONS: The present study shows that the positive predictive value of PSA screening in BRCA mutation carriers is high and that screening detects clinically significant prostate cancer. These results support the rationale for continued screening in such men.

Regulation of transcriptional activity of the murine CD40 ligand promoter in response to signals through TCR and the costimulatory molecules CD28 and CD2.

We have analyzed the murine CD40 ligand promoter with regard to stimulation of transcriptional activity in Jurkat T cells after signaling via the TCR and the costimulatory molecules CD28 and CD2. TCR engagement was necessary for the induction of transcriptional activity from the CD40 ligand promoter, and costimulation through either CD28 or CD2 further increased the activity. Analysis of promoter deletants showed that the DNA elements needed for transcriptional activity induced by costimulatory molecules were located within two regions containing previously identified transcription factor NFAT sites. Further studies of the proximal NFAT site showed that it was not dependent on AP-1 binding for transcriptional activity induced by costimulation through CD28. Instead, a region between the TATA box and the proximal NFAT site was shown to bind proteins of the early growth response family and to contribute to NFAT-mediated transcriptional activation.

Phenotypic convergence and divergence of surface immunoglobulin and CD40 signals.

Both anti-CD40 antibodies and anti-immunoglobulin (Ig) coupled to Sepharose induced proliferation of resting B cells and suppressed lipopolysaccharide (LPS)-induced B-cell differentiation to immunoglobulin secretion at comparable levels determined with the plaque-forming assay and Ig RNA steady state levels. Anti-CD40 antibodies also increased the proliferation of B cells stimulated by T helper cells in vitro while suppressing their differentiation to Ig secretion. Further, B cells preactivated by anti-Ig, anti-CD40 or a combination of the two mitogens could be restimulated by anti-CD40 but not by anti-Ig antibodies. Phenotypic divergence of Ig and CD40 signals regarding surface expression of activation markers was observed. Restimulation of anti-Ig- or anti-CD40-prestimulated cells with anti-Ig induced apoptosis whereas apoptosis could be inhibited when cells were recultivated with anti-CD40.

Regulation of B cell growth and differentiation via CD21 and CD40.

Stimulation in vitro of murine splenic B cells by lipopolysaccharide, anti-kappa Sepharose, anti-CD40 or allo-reactive T helper cells all up-regulated CD21 and CD23 surface expression. Neither anti-CD21 nor anti-CD23 antibodies induced B cell growth or differentiation when added in soluble form or coupled to Sepharose. However, anti-CD40-stimulated B cells showed increased proliferation in the presence of anti-CD21 antibodies coupled to Sepharose; co-stimulation via CD21 also induced differentiation to immunoglobulin secretion in a fraction of anti-CD40-stimulated B cells. Furthermore, anti-CD40 antibodies inhibited differentiation to immunoglobulin secretion induced by lipopolysaccharide and, hence, appears to be a dominant negative signal for B cell differentiation.

Multiple ligand interactions for bacterial immunoglobulin-binding proteins on human and murine cells of the hematopoetic lineage.

A group of bacterial Ig-binding surface proteins were studied: protein H and M1 are from Streptococcus pyogenes and interact with IgG, protein L is expressed by Peptostreptococcus magnus and shows affinity for Ig light chains, whereas protein LG is a chimeric construction combining the binding properties of protein L with the IgG-binding activity of protein G from group C and G streptococci. Proteins L and H coupled to Sepharose were mitogenic for human peripheral blood lymphocytes (PBL) and mouse splenic B cells, but not when added in soluble form. Differentiation to Ig secretion was induced by protein H-Sepharose in mouse splenic B cells but not in human PBLs. In FACS analysis FITC-labelled protein H stained virtually all CD19+ cells in human peripheral blood as well as a majority of the CD3+ population. Protein L bound the majority of the CD19+ population, but also a fraction of the CD19-/CD3 population. Protein M1 was not mitogenic but stained the entire CD19+ population and 70% of the CD3+ population. Identical staining patterns were observed with mouse splenocytes using B220 and T-cells receptor as lineage markers. The chimeric protein LG was a potent mitogen for mouse splenic B cells when added either coupled to Sepharose or in soluble form. In addition, protein LG induced differentiation to Ig secretion of the responding mouse splenic B cells. In FACS analysis, protein LG stained the entire CD19+ and the majority of the CD19-/CD3 lymphocyte population as well as all B220+ mouse splenocytes and a fraction of the splenic T cells. These data indicate that the bacterial proteins studied interact with surface structures of several leucocyte populations and can hence interfere with the immune system at multiple levels.