Hannes Steiner

Interleukin‐6 regulation of prostate cancer cell growth

Interleukin‐6 (IL‐6) is involved in regulation of immune reaction and cell growth and differentiation. It causes multifunctional responses ranging from inhibition of proliferation to promotion of cell survival. IL‐6 effects may depend on experimental conditions such as passage numbers and serum composition. IL‐6 signals in target tissues through the receptor that is composed of the ligand‐binding and signal‐transducing subunits. IL‐6 is expressed in benign and malignant prostate tissue and the levels of the cytokine and its receptor increase during prostate carcinogenesis. IL‐6 is considered a positive growth factor for most prostate cells. The only exemption seems to be the LNCaP cell line, in which IL‐6 causes growth arrest and induces differentiation function. In contrast, IL‐6 acts as an autocrine growth factor in the subline LNCaP‐IL‐6+ established after chronic treatment with IL‐6. IL‐6 is a candidate for targeted therapy in prostate cancer because of its association with morbidity. Activation of signaling pathways of Janus kinase/signal transducers and activators of transcription factors, mitogen‐activated protein kinase (MAPK), and phosphatidylinositol 3‐kinase has been reported in various prostate cancer cell lines. IL‐6 and the related cytokine oncostatin M induce activation of the androgen receptor (AR) in the absence of androgen. IL‐6 is also involved in regulation of vascular endothelial growth factor expression as well as neuroendocrine differentiation in prostate. Anti‐IL‐6 antibodies showed an inhibitory effect on the PC‐3 xenograft. However, the development of this therapy in prostate cancer is in early stages.

Comparison Of Contrast Enhanced Color Doppler Targeted Biopsy With Conventional Systematic Biopsy: Impact On Prostate Cancer Detection

Purpose: We performed a prospective study to determine whether a limited biopsy approach with contrast enhanced color Doppler ultrasound targeted biopsy of the prostate would detect cancer as well as gray scale US guided systematic biopsy with a larger number of biopsy cores.Materials and Methods: We examined 230 male screening volunteers with a total prostate specific antigen of 1.25 ng./ml. or greater and free-to-total prostate specific antigen less than 18%. Two independent examiners evaluated each subject and a single investigator performed 5 or fewer contrast enhanced targeted biopsies into hypervascular regions in the peripheral zone during intravenous infusion of the US contrast agent Levovist (Schering, Berlin, Germany). Subsequently another examiner performed 10 systematic prostate biopsies. The cancer detection rates of the 2 techniques were compared.Results: Cancer was detected in 69 of the 230 patients (30%), including 56 (24.4%) by contrast enhanced targeted biopsy and in 52 (22.6%) by system...

Interleukin-6 stimulation of growth of prostate cancer in vitro and in vivo through activation of the androgen receptor

It is hypothesized that ligand-independent activation of the androgen receptor is one of the mechanisms implicated in tumour progression. However, supportive evidence is limited to the effect of HER-2/neu that stimulates prostate cancer progression through activation of the androgen receptor. In the present study, we have asked whether the proinflammatory cytokine interleukin-6 (IL-6), which is known to stimulate androgen receptor activity and expression of its downstream target genes, may also induce growth of androgen-sensitive cells. We have found that IL-6 differentially regulates proliferation of LAPC-4 and MDA PCa 2b cells. In MDA PCa 2b cells, growth stimulation by IL-6 was reversed by administration of either the non-steroidal anti-androgen bicalutamide or the inhibitor of the mitogen-activated protein kinase pathway PD98059. Neither cell line was found to express endogenous IL-6. Interestingly, the treatment of those prostate cancer cells did not increase phosphorylation of STAT3. The effect of IL-6 on stimulation of androgen receptor activity in MDA PCa 2b cells was lower than that of androgen, comparable with findings reported by other researchers. However, growth of MDA PCa 2b xenografts in castrated animals treated with IL-6 was similar to that in non-castrated animals. In addition, bicalutamide showed an inhibitory effect on IL-6-regulated growth in vivo. Taken together, data in the present study demonstrate that IL-6 may cause growth of androgen receptor-positive tumours in vitro and in vivo through activation of the androgen receptor.

Expression and function of androgen receptor coactivators in prostate cancer

Human androgen receptor (AR) associates with coactivator or corepressor proteins that modulate its activation in the presence of ligand. Early studies on AR coactivators in carcinoma of the prostate were hampered because of lack of respective antibodies. Investigations at mRNA level revealed that most benign and malignant prostate cells express common coactivators. AR coactivators SRC-1 and TIF-2 are up-regulated in tissue specimens obtained from patients who failed prostate cancer endocrine therapy. Increased expression of these coactivators is associated with enhanced activation of the AR by the adrenal androgen dehydroepiandrosterone. Similar association between AR coactivator expression and high prostate cancer grade and stage was reported for RAC-3 (SRC-3). The transcriptional integrator CBP was detected in clinical specimens representing organ-confined prostate cancer, lymph node metastases and tumour cell lines. Agonistic effect of the nonsteroidal antiandrogen hydroxyflutamide was strongly potentiated in prostate cells transfected with CBP cDNA. A functional homologue of CBP, p300, is implicated in ligand-independent AR activation by interleukin-6. The AR coactivator Tip60, which is up-regulated by androgen ablation, is recruited to the promoter of the prostate-specific antigen gene in the absence of androgen in androgen-independent prostate cancer sublines. It was proposed that the cofactor ARA70 is a specific enhancer of AR action. However, research from other laboratories has demonstrated interaction between ARA70 and other steroid receptors. Although in some cases dominant-negative coactivator mutants inhibited proliferation of prostate cancer cells in vitro, confirmation from in vivo tumour models is missing. In summary, several abnormalities in AR coactivator expression and function are associated with prostate cancer progression.

Photodynamic therapy with intravesical instillation of 5-aminolevulinic acid for patients with recurrent superficial bladder cancer: a single-center study

OBJECTIVES Photodynamic therapy (PDT) is an effective treatment option for patients with superficial bladder cancer uncontrolled by transurethral resection and/or intravesical bacille Calmette-Guérin (BCG) immunotherapy alone. We determined the efficacy and side effects of PDT in patients with recurrent superficial bladder cancer. METHODS Between April 1994 and July 2001, PDT was performed in 31 patients (23 men and 8 women). 5-Aminolevulinic acid (50 mL) in a 3% concentration was instilled intravesically. Patients were instructed to hold the solution as long as possible and were irradiated transurethrally with a mean light dose of 3.9 W using laser light emitting a wavelength of 633 nm for a mean time of 1260 seconds. RESULTS The mean patient age at the procedure was 70.2 years. At an average follow-up of 23.7 months (range 1 to 73), 16 patients were free of tumor recurrence; 15 patients had developed tumor recurrence after a mean of 8.3 months. Of 10 patients with prior BCG treatment, 4 were free of tumor recurrence. Treatment was well tolerated, with the only side effect being dysuria due to urinary tract infection in 4 patients and hematuria in 7 patients. No phototoxic skin reactions were observed. CONCLUSIONS PDT represents a safe, effective, and less-invasive treatment for patients with recurrent superficial bladder cancer. Because of the favorable side-effect profile, PDT can also be applied to patients with comorbidity precluding surgical treatment. Furthermore, PDT represents a second-line treatment for patients with tumor recurrence after BCG failure.

Accelerated in Vivo Growth of Prostate Tumors that Up-Regulate Interleukin-6 Is Associated with Reduced Retinoblastoma Protein Expression and Activation of the Mitogen-Activated Protein Kinase Pathway

Interleukin-6 (IL-6) is a multifunctional cytokine that activates the signaling pathways of Janus kinases-signal transducers and activators of transcription (STAT) and/or mitogen-activated protein kinases (MAPK) in various tumors. Thus, it modulates cell growth and apoptosis. IL-6 levels are elevated in tissues and sera from prostate cancer patients and IL-6 receptor expression has been detected in prostate cancer cell lines and clinical specimens. Continuous exposure of prostate cancer cells to IL-6 might alter their responsiveness to this cytokine. To gain more insight into the function of IL-6 in prostate carcinoma, we have inoculated LNCaP-IL-6+ cells, generated after prolonged treatment with IL-6, into nude mice (total n = 16, two independent experiments). Controls included animals bearing LNCaP-IL-6- cells, passaged at the same time as LNCaP-IL-6+ cells without supplementation of IL-6. LNCaP-IL-6+ tumor volumes were larger than those of their counterparts at all time points. There were no signs of cachexia in any of the experimental animals and all mice were free of metastases. To better understand the mechanisms responsible for accelerated growth of LNCaP-IL-6+ tumors, we have investigated the expression of cell-cycle regulatory molecules by Western blot analysis. The levels of cyclin-dependent kinase 2 were elevated in LNCaP-IL-6+ cells. There was a strong down-regulation of cyclins D1 and E in the LNCaP-IL-6+ subline. The cell-cycle inhibitor p27 was expressed at a low level in LNCaP-IL-6+ cells and could not be up-regulated by addition of IL-6. Most notably, LNCaP-IL-6+ cells exhibited a reduced expression of the hypophosphorylated form of the retinoblastoma protein (pRb). Accelerated tumor growth in our model system was also associated with alterations in IL-6-signaling pathways. The ability of IL-6 to induce tyrosine phosphorylation of STAT3 was abolished in the LNCaP-IL-6+ subline. In contrast, the levels of the MAPK extracellular signal-regulated kinases 1/2 increased in cells generated after long-term IL-6 treatment. The inhibitor of MAPK kinase PD 98059 retarded the proliferation of LNCaP-IL-6+ but not that of control cells. In summary, we show in the present study that chronic exposure of prostate cancer cells to IL-6 facilitates tumor growth in vivo by abolishment of the growth control by pRb and activation of the MAPK signaling pathway. These findings could be relevant to understand the role of IL-6 in prostate cancer progression.

The antiapoptotic effect of IL-6 autocrine loop in a cellular model of advanced prostate cancer is mediated by Mcl-1

Levels of the proinflammatory cytokine interleukin-6 (IL-6) are increased in therapy-resistant prostate cancer. IL-6 has been considered a positive growth factor in late-stage prostate cancer cells and a potential target for therapeutic interference. Effects of inhibition of IL-6 on cell survival were studied in LNCaP-IL6+ cells, a model system for advanced prostate cancer, which produce IL-6. We show that the autocrine IL-6 loop is responsible for resistance to apoptosis and increased cellular levels of myeloid cell leukemia-1 (Mcl-1) protein, an antiapoptotic member of the Bcl-2 family. Treatment of cells with a chimeric anti-IL-6 antibody (CNTO 328) led to the induction of apoptosis and downregulation of Mcl-1 protein levels. Specific knockdown of Mcl-1 gene expression by small interfering RNA also yielded an increase in apoptosis of LNCaP-IL-6+ cells. Vice versa, inactivation of IL-6 autocrine loop had no influence on apoptosis levels in the absence of Mcl-1, thus suggesting this molecule as a mediator of the survival action of IL-6. Mcl-1 protein regulation by the endogenous cytokine directly involved the extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase pathway. Our data support the concept of anti-IL-6 targeted therapy in therapy-resistant prostate cancer.

Frozen section analysis-guided organ-sparing approach in testicular tumors: Technique, feasibility, and long-term results

OBJECTIVES To evaluate retrospectively the indications, surgical technique, feasibility, and follow-up data of our frozen section analysis-guided organ-sparing approach to small testicular tumors. Removal of a solitary testis or bilateral orchiectomy for testicular neoplasm results in androgen deprivation and infertility. Moreover, removal of a testis for benign lesions is to be avoided. Organ-sparing surgery aims at preserving enough testicular parenchyma to maintain physiologic endocrine function and, if possible, fertility. METHODS Tumors of 25 mm or less in diameter were managed by an organ-sparing approach. Normal preoperative plasma levels of luteinizing hormone and testosterone were a prerequisite. After localization of the tumor by ultrasonography and accurate staging, organ-sparing surgery was performed under cold ischemia. Frozen section analyses of the tumor and tumor bed biopsies were obtained. In the case of malignant germ cell tumor with a normal contralateral testis, ablation of the tumor-bearing testis was performed. RESULTS A total of 32 organ-preserving procedures were performed in 30 patients without any complications. Local recurrence was observed in 1 patient who refused to undergo local radiotherapy for concomitant testicular intraepithelial neoplasia; repeat organ-sparing surgery was performed in this patient. After organ-sparing surgery, ablation of the remaining testis was performed in 1 patient because of positive margins on final histologic analysis and in another patient because of endocrine insufficiency. In all other patients, the serum testosterone levels remained within normal limits. No retroperitoneal, pulmonary, or other recurrences were encountered; all patients were free of disease at a mean follow-up of 46.3 months. CONCLUSIONS The organ-sparing frozen section analysis-guided approach to testicular masses represents a promising treatment alternative to orchiectomy in selected patients with bilateral malignant testicular tumors, tumors in a solitary testis, or unilateral or bilateral benign tumors. The technique is oncologically efficient, lifelong hormonal substitution can be prevented, and, in some patients, even fertility may be preserved, provided certain criteria concerning patient selection and surgical technique are observed.

The anti-interleukin-6 antibody siltuximab down-regulates genes implicated in tumorigenesis in prostate cancer patients from a phase I study†‡§

Interleukin‐6 (IL‐6) is associated with prostate cancer morbidity. In several experimental models, IL‐6 has been reported to have anti‐apoptotic and pro‐angiogenic effects. Siltuximab (CNTO 328) is a monoclonal anti‐IL‐6 antibody which has been successfully applied in several models representing prostate cancer. This study was designed to assess preliminary safety of siltuximab in patients with early prostate cancer.

Long-term experience with carboplatin monotherapy for clinical stage I seminoma: a retrospective single-center study

OBJECTIVES To evaluate the long-term oncologic efficacy and morbidity of carboplatin monotherapy, which was introduced at our department 11 years ago for the treatment of Stage I seminoma. Radiotherapy is the standard treatment of patients with clinical Stage I seminoma. Carboplatin has been advocated as a treatment alternative to avoid the late side effects of radiotherapy and the high recurrence rate of surveillance strategies. METHODS From February 1990 until August 2001, 108 patients received two adjuvant cycles of single-agent carboplatin (400 mg/m2 body surface on days 1 and 22) 2 weeks after high inguinal orchiectomy. To assess for myelosuppression, complete blood counts were performed at least once a week until the nadir occurred after the second treatment cycle. RESULTS During a mean follow-up period of 59.8 months (range 6 to 134), 2 patients (1.85%) developed a recurrence (retroperitoneal tumor) within the first year. Both patients received cisplatin-based salvage chemotherapy. At last follow-up, all patients were alive without any evidence of disease. Carboplatin treatment was well tolerated by all patients and was associated with only mild gastrointestinal side effects. Leukopenia was noted in 32 patients (29.6%); 21 (19.4%) of these patients had World Health Organization (WHO) grade 1, 8 (7.4%) had grade 2, 3 (2.8%) had grade 3, and none had grade 4. No patient developed neutropenic fever. Thrombocytopenia was observed in 48 patients (44.4%); of these patients, 38 (35.2%) had WHO grade 1, 5 (4.6%) had grade 2, 2 (1.9%) had grade 3, and 3 (2.8%) had grade 4. CONCLUSIONS From an oncologic standpoint, two cycles of carboplatin monotherapy was highly effective and very well tolerated by all patients.