Functional angiotensin II type 2 receptors inhibit growth factor signaling in LNCaP and PC3 prostate cancer cell lines

BACKGROUND: There is clear evidence of a tissue-based renin-angiotensin system in the prostate and studies to date suggest that AT(1)-receptor blocking drugs inhibit the growth of some prostate cancer cell lines and delay the development of prostate cancer. The present studies examine the action of Ang II in two prostate cancer cell lines and report the presence of functional AT(2)-receptors that regulate the actions of growth factors. METHODS: Immunohistochemistry was used to identify the presence of Ang II and QPCR techniques to examine AT(1)- and AT(2)-receptor mRNA expression in androgen-dependent (LNCaP) and independent (PC3) cell lines. The effects of AT(1)- and AT(2)-receptor activation upon EGF-induced DNA synthesis and ERK2 phosphorylation in these cells were also examined. RESULTS: Functional AT(2)-receptors together with Ang II were identified in both cell lines and stimulation of these receptors inhibited EGF-induced DNA synthesis and ERK2 phosphorylation. AT(1)-receptors, although present in both cell lines, were only functional in LNCaP cells where activation stimulated DNA synthesis. CONCLUSIONS: Functional AT(2)-receptors are present and have the capacity to inhibit EGF-induced prostate cancer cell growth in LNCaP and fast growing androgen-independent PC3 cell lines, whereas functional AT(1)-receptors are found only in LNCaP cells where their activation stimulates DNA synthesis.     

A phase II study of high-dose calcitriol combined with mitoxantrone and prednisone for androgen-independent prostate cancer

OBJECTIVE

To evaluate the preliminary efficacy, safety, and impact on quality of life (QoL) of high‐dose calcitriol (DN‐101) combined with mitoxantrone and glucocorticoids in androgen‐independent prostate cancer (AIPC).

PATIENTS AND METHODS

Nineteen patients with metastatic AIPC and no previous chemotherapy received DN‐101 180 µg orally on day 1 and mitoxantrone 12 mg/m² intravenously on day 2 every 21 days with continuous daily prednisone 10 mg orally for a maximum of 12 cycles. A confirmed decline in prostate‐specific antigen (PSA) levels by half was the primary endpoint. QoL was evaluated using the European Organization for Research and Treatment of Cancer QLQ‐C30 questionnaire, and pain and analgesic use were evaluated.

RESULTS

Five of 19 patients (26%; 95% confidence interval, CI, 9–51) achieved a ≥50% decline in PSA level. The median (95% CI) time to PSA progression was 16 (6–26) weeks. The overall median (95% CI) survival was 16 (6–26) months; 47 (21–73)% of patients achieved an analgesic response. Toxicity was similar to that expected with mitoxantrone and prednisone alone. The QoL analysis suggested a decrease in physical functioning and increase in fatigue, insomnia, and diarrhoea.

CONCLUSIONS

DN‐101 given every 3 weeks does not add significant activity to mitoxantrone and prednisone in AIPC, as measured by the PSA decline. The high rate of analgesic response is encouraging. The addition of DN‐101 does not appear to increase the toxicity of mitoxantrone.     

A comparison of white-light cystoscopy and narrow-band imaging cystoscopy to detect bladder tumour recurrences

OBJECTIVE

To determine whether narrow‐band imaging (NBI) cystoscopy enhances the detection of non‐muscle‐invasive bladder tumours over standard white‐light imaging (WLI) cystoscopy, as surveillance WLI is the standard method used to diagnose patients with recurrent bladder tumours, but they can be missed by WLI cystoscopy, possibly accounting for early recurrences.

PATIENTS AND METHODS

We evaluated 427 patients for recurrent bladder tumours by WLI cystoscopy, followed by NBI cystoscopy as a further procedure, using the same video‐cystoscope. Recurrent tumours visualized by WLI or NBI cystoscopy were mapped, imaged, biopsied and subsequently treated by transurethral resection (TUR) or fulguration. Biopsies or TUR specimens obtained by WLI and NBI were examined separately for presence of tumour.

RESULTS

In all, 103 patients (24%) had tumour recurrences; 90 (87%) were detected by both WLI and NBI and another 13 (100%) only by NBI cystoscopy. NBI detected extra papillary tumours or more extensive carcinoma in situ in 58 (56%) patients found to have recurrences. The mean number of recurrent tumours visualized on WLI cystoscopy was 2.3, vs to 3.4 seen on NBI cystoscopy (P = 0.01).

CONCLUSION

NBI cystoscopy improved the detection of recurrent non‐muscle‐invasive bladder tumours over standard WLI cystoscopy.     

Impact of triple negative phenotype on breast cancer prognosis

Triple negative (TN) [estrogen receptor (ER), progesterone receptor (PgR)] (ER-/PgR-/Her2/neu-) breast cancer (BC) is an aggressive disease without tumor-specific treatment options. Our objective is to evaluate the relative contribution of combined Her2/neu (Her2) and hormone receptor (HR) status to BC progression. A prospective primary BC cohort of 1550 patients at our institution, stage I-IV, from 1998 to 2003 were categorized by HR and Her2 status into ER+/PgR+/Her2- (HR+/Her2-) (n = 1134), ER+/PgR+/Her2+ [triple positive (TP)] (n = 138), ER-/PgR-/Her2- (TN) (n = 183), and ER-/PgR-/Her2+ (HR-/Her2+) (n = 95). Clinical variables were chart abstracted and vital and disease status updated annually. Log-rank tests and Cox regression analyses were used to assess associations with survival. Patient age ranged from 21 to 88 years and average length of follow-up was 4.24 years. Overall survival at 5 years was 94% (HR+/Her2-), 91% (TP), and 81% (TN and HR-/Her2+) (log rank test = 22.22, p < 0.001). Disease-specific survival at 5 years was 98% (HR+/Her2-), 93% (TP), 88% (TN), and 86% (HR-/Her2+) (log rank test = 25.85, p < 0.001) and 5-year relapse-free survival was 95% (HR+/Her2-), 89% (TP), 84% (TN), and 76% (HR-/Her2+) (log rank test = 20.29, p < 0.001). In a model adjusted for age, race, TNM stage, and treatment using HR+/Her2- patients as the reference group, recurrence risk was 1.98 for TP (95% CI = 1.02 to 3.84), 2.32 for TN (95% CI = 1.32 to 4.08), and 4.25 for HR-/Her2+ patients (95% CI = 2.33, 7.75). A hierarchy of BC phenotypes defined by HR and Her2 status exists with progressively worse disease outcomes by category.     

Retrospective clinical evaluation of gauze-based negative pressure wound therapy

Negative pressure wound therapy (NPWT) is an established modality in the treatment of challenging wounds. However, most existing clinical evidence is derived from the use of open-cell polyurethane foam at -125 mmHg. Alternative negative pressure systems are becoming available, which use gauze at a pressure of -80 mmHg. This study describes clinical results from a retrospective non comparative analysis of 30 patients treated with Chariker-Jeter gauze-based negative pressure systems (V1STA, Versatile-1 and EZ-Care; Smith & Nephew, Inc.) in a long-term care setting. The mean age of the patients was 72 years. The wounds consisted of chronic (n = 11), surgical dehiscence (n = 11) and surgical incision (n = 8). Wound volume and area were recorded at commencement and at the cessation of therapy. Discontinuation of therapy was instigated upon closure through secondary intention or when size and exudate were sufficiently reduced that the wounds could be managed by conventional wound dressing (median 41 days). An overall median reduction in wound volume of 88.0% (P < 0.001) and a 68.0% reduction in area (P < 0.001) compared with baseline were observed over the course of NPWT. The overall rate of volume reduction (15.1% per week) compares favourably with published data from foam-based systems.     

A systematic review of the effectiveness of negative pressure wound therapy in the management of diabetes foot ulcers

Foot ulcers are a common complication in patients with diabetes. Negative pressure wound therapy (NPWT) is a wound care therapy that is being increasingly used in the management of foot ulcers. This article presents a systematic review examining the effectiveness of this therapy. The review question is how effective is NPWT in achieving wound healing in diabetes foot ulcers? The primary outcome for this study was the number of patients achieving complete wound healing (secondary outcomes, other markers of wound healing, adverse events and patient satisfaction). A systematic literature review and tabulative synthesis of randomised controlled trials (RCTs). The review identified four RCTs of weak to moderate quality. Only one study examining NPWT in postamputation wound healing reported data on the primary outcome. These data show a 20% improvement in wound healing [odds ratios = 2·0%, confidence interval (CI) ?1·0 to 4·0] and number needed to treat = 6 (CI 4–64). No serious treatment‐related complications were reported by any of the studies. One study suggested a reduction in the risk of secondary amputation (absolute risk reduction = 7·9%, CI 0·5–15·43). Studies also reported an increase in granulation and wound‐healing rates in patients treated with NPWT therapy. No data on patient satisfaction or experience were reported. While all the studies included in the review indicated that the NPWT therapy is more effective than conventional dressings, the quality of the studies were weak and the nature of the inquiries in terms of outcome and patient selection divergent. There is a strong need for larger trials to assess NPWT therapy in diabetes care with different groups of patients and in relation to different clinical objectives and parameters.     

Proteomic analysis to identify biomarker proteins in pancreatic ductal adenocarcinoma

Background: Pancreatic ductal adenocarcinoma (PDAC) is the fifth most common cause of death from cancer in Korea. PDAC is difficult to diagnose at an early stage and even more difficult to cure. Thus, there is an urgent need to identify molecular targets for early diagnosis and effective treatment. The objectives of this study were to identify differentially expressed biomarker proteins of PDAC using proteomic analysis, to validate the identified biomarker proteins associated with carcinogenesis using western blot analysis and to evaluate clinical factors influencing expression of candidate biomarker proteins. Methods: In the present study, we carried out proteomic analysis in 10 pairs of PDAC specimens with matching adjacent normal tissues to clarify the different patterns of protein expression. The proteins were separated by high‐resolution 2‐D polyacrylamide gel electrophoresis (2D PAGE) and the differentially expressed proteins were identified by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). Differential expression of candidate biomarker proteins associated with carcinogenesis was further validated using western blot analysis. Standard statistical analysis was carried out in an attempt to establish a correlation between clinical variables and expression of candidate biomarker proteins. Results: Analysis of PDAC and the adjacent normal tissues showed reproducibly similar proteomic patterns for each group. Approximately 700 spots each were seen by silver‐stained gels from both PDAC and normal tissues. Differentially expressed protein spots were gel digested and identified by MALDI‐TOF MS. Twenty‐five proteins were identified, of which five proteins (galectin‐1, enolase‐2, α‐1‐antitrypsin, N‐myc interactor, peroxiredoxin‐4) were previously reported as being differentially expressed either at the mRNA level or protein level in human cancer. The five proteins were selected for candidate biomarker proteins related to carcinogenesis. These proteins were further validated by western blot analysis. Among the candidate biomarker proteins, galectin‐1 expression was highly correlated to histology (P = 0.019), T stage (P = 0.047), N stage (P = 0.033) and American Joint Committee on Cancer stage (P = 0.011). Conclusion: Differentially expressed 25 proteins in PDAC were identified using proteomic analysis and five proteins related to carcinogenesis were validated by western blot analysis. galectin‐1 expression was highly correlated to tumour histology and stage.     

Clusterin knockdown using the antisense oligonucleotide OGX-011 re-sensitizes docetaxel-refractory prostate cancer PC-3 cells to chemotherapy

OBJECTIVES

To characterize changes in secretory clusterin (sCLU) expression in prostate cancer cells after treatment with docetaxel and to determine whether sCLU knockdown can re‐introduce chemosensitivity in a docetaxel‐resistant, androgen‐independent human prostate cancer model.

PATIENTS AND METHODS

A tissue microarray was constructed for 84 radical prostatectomy (RP) specimens from a multicentre Phase II trial of neoadjuvant combined androgen ablation and docetaxel (CUOG‐P01a) and assessed for changes in the expression of the cytoprotective chaperone sCLU. The human prostate cancer cell line PC‐3 was repeatedly exposed to docetaxel chemotherapy in vitro, and a docetaxel‐resistant cell subline (PC‐3dR) was developed and analysed.

RESULTS

sCLU levels were significantly higher in RP specimens treated with neoadjuvant combined androgen ablation and docetaxel than in untreated specimens. Similarly, sCLU expression increased 2.5‐fold in the newly developed docetaxel‐refractory PC‐3dR cell line compared with parental PC‐3 cells. There was a dose‐dependent and sequence‐specific decrease in sCLU levels in PC‐3dR cells using OGX‐011, an antisense oligonucleotide against human sCLU. OGX‐011 and small‐interference RNA both chemosensitized PC‐3dR cells to docetaxel and mitoxantrone in vitro and apoptotic rates in PC‐3dR cells were significantly increased when OGX‐011 was combined with docetaxel. In vivo, growth of PC‐3dR xenografts in nude mice was synergistically inhibited by OGX‐011 combined with paclitaxel or mitoxantrone (by 76% and 44% compared with their mismatch controls, respectively).

CONCLUSION

The present findings indicate that targeted knockdown of sCLU enhances the effects of cytotoxic chemotherapy in docetaxel‐refractory cells, and provide preclinical proof of principle for clinical trials testing OGX‐011 in second‐line chemotherapy regimens for patients with docetaxel‐refractory prostate cancer.     

Effect of muscle-derived stem cells on the restoration of corpora cavernosa smooth muscle and erectile function in the aged rat

OBJECTIVE

To determine whether skeletal muscle‐derived stem cells (MDSCs) convert into smooth muscle cells (SMCs) both in vitro and in vivo, and in so doing ameliorate the erectile dysfunction (ED) of aged rats, and whether endogenous stem cells are present in the rat corpora cavernosa.

MATERIALS AND METHODS

MDSCs were obtained from mouse muscle, and shown by immunocytochemistry for α‐smooth muscle actin (αSMA) to originate in vitro in myofibroblasts and SMCs, discriminating SMCs by calponin 1 expression. In vivo these MDSCs, labelled with 4′,6‐diamidino‐2‐phenylindole, were implanted into the corpora cavernosa of young adult (5‐month old) and aged (20‐month old) rats for 2 and 4 weeks. Histological changes were assessed by immunohistochemistry and quantitative Western blot. Functional changes were determined by electrical field stimulation (EFS) of the cavernosal nerve.

RESULTS

The exogenous cells replicated and converted into SMCs, as shown in corporal tissue sections by confocal immunofluorescence microscopy for proliferating cell nuclear antigen (PCNA), αSMA, and smoothelin, and also by Western blot for αSMA and PCNA. MDSC differentiation was confirmed by the activation of the αSMA promoter‐linked β‐galactosidase in transfected cells, both in vitro and after implantation in the corpora. Putative endogenous stem cells were shown in corporal tissue sections and Western blots by detecting CD34 and a possible Sca1 variant. EFS showed that implanted MDSCs raised in aged rats the maximal intracavernosal pressure/mean arterial pressure levels above (2 weeks) or up to (4 weeks) those of young adult rats.

CONCLUSIONS

MDSCs implanted into the corpora cavernosa of aged rats converted into SMCs and corrected ED, and endogenous cells expressing stem cell markers were also found in untreated tissue. This suggests that exogenous stem cell implantation and/or endogenous stem cell modulation might be viable therapeutic approaches for ageing‐related ED.