Probenecid ameliorates testosterone-induced benign prostatic hyperplasia: Implications of PGE-2 on ADAM-17/EGFR/ERK1/2 signaling cascade.

Benign prostatic hyperplasia (BPH) is one of the most prevalent clinical disorders in the elderly. Probenecid (Prob) is a well-known FDA-approved therapy for gout owing to its uricosuric effect. The present study evaluated the use of Prob for BPH as a COX-2 inhibitor. Prob (100 and 200 mg/kg) was intraperitoneally injected into male Wistar rats daily for 3 weeks. In the second week, testosterone (3 mg/kg) was subcutaneously injected to induce BPH. Compared with BPH-induced rats, Prob treatment reduced prostate weight and index and improved histopathological architecture. The protease activity of ADAM-17/TACE and its ligands (TGF-α and TNF-α) were regulated by prob, which in turn abolished EGFR phosphorylation, and several inflammatory mediators (COX-2, PGE2, NF-κB (p65), and IL-6) were suppressed. By reducing the nuclear import of extracellular regulated kinase protein 1/2 (ERK1/2), Prob helped re-establish the usual equilibrium between antiapoptotic proteins like Bcl-2 and cyclin D1 and proapoptotic proteins like Bax. All of these data point to Prob as a promising treatment for BPH because of its ability to inhibit COX-2-syntheiszed PGE2 and control the ADAM-17/TGF-α-induced EGFR/ERK1/2 signaling cascade. These findings might help to repurpose Prob for the treatment of BPH.

Cyclooxygenase-2 activates EGFR-ERK1/2 pathway via PGE2-mediated ADAM-17 signaling in testosterone-induced benign prostatic hyperplasia.

OBJECTIVE AND DESIGN: Prostatic inflammation is the driving force in benign prostatic hyperplasia (BPH). This work investigated the potential modulatory effect of COX-2 inhibition on ADAM-17/EGFR/ERK1/2 axis. MATERIALS OR SUBJECTS: Adult male Wistar rats were used. TREATMENT: Celecoxib (10 and 20 mg/kg; i.p.) was injected i.p. daily for three weeks. Testosterone (TST) (3 mg/kg; s.c.) was used to induce BPH. METHODS: Prostatic inflammation and hyperplasia were assessed by organ weight and histopathology. Inflammatory mediators were measured using ELISA technique. Protein analysis was performed using western blotting and immunohistochemistry. Gene expression analysis was performed using qRT-PCR. Statistical analyses included one-way ANOVA and Tukey's multiple comparison test. RESULTS: Testosterone-treated rats had a marked increase in COX-2, prostate weight, and index. Moreover, TST-induced COX-2 was inferred from cytoskeletal changes and was attributable to the overexpression of PGE2, NF-κB (p65), and IL-6. COX-2-derived PGE2 increased the activity of ADAM-17, TGF-α, and TNF-α. Consequently, EGFR-ERK1/2 pathway was over-activated, disrupting anti-apoptotic Bcl-2, cyclin D1, and pro-apoptotic Bax. Celecoxib reversed these effects. CONCLUSION: COX-2 stimulates the ERK1/2 pathway via PGE2-ADAM-17-catalyzed shedding of TGF-α in testosterone-induced BPH. The results indicate a functional correlation between inflammation and hyperplasia in BPH.

Attenuation of Allergen-, IL-13-, and TGF-α-induced Lung Fibrosis after the Treatment of rIL-15 in Mice.

Endogenous IL-15 deficiency promotes lung fibrosis; therefore, we examined the effect of induced IL-15 in restricting the progression of lung fibrosis. Our objective in this work was to establish a novel therapeutic molecule for pulmonary fibrosis. Western blot, qPCR, and ELISA were performed on the lung tissues of IL-15-deficient mice, and recombinant IL-15 (rIL-15)-treated CC10-IL-13 and CC10-TGF-α mice, and allergen-challenged CC10-IL-15 mice were examined to establish the antifibrotic effect of IL-15 in lung fibrosis. We show that endogenous IL-15 deficiency induces baseline profibrotic cytokine and collagen accumulation in the lung, and pharmacological delivery of rIL-15 downregulates Aspergillus antigen-induced lung collagen, the profibrotic cytokines IL-13 and TGF-ß1, and α-SMA+ and FSP1+ cells in mice. To confirm that overexpression of IL-15 diminishes pulmonary fibrosis, we generated CC10-rtTA-tetO7-IL-15 transgenic mice and challenged them with Aspergillus antigen. Aspergillus antigen-challenged, doxycycline (DOX)-treated CC10-IL-15 transgenic mice exhibited decreased collagen accumulation, profibrotic cytokine (IL-13 and TGF-ß1) expression, and α-SMA+ and FSP1+ cells compared with IL-15-overexpressing mice not treated with DOX. Additionally, to establish that the antifibrotic effect of IL-15 is not limited to allergen-induced fibrosis, we showed that rIL-15 or IL-15 agonist treatment restricted pulmonary fibrosis even in CC10-IL-13 and CC10-TGF-α mice. Mechanistically, we show that T-helper cell type 17 suppressor IL-15-responsive RORγ+ T regulatory cells are induced in DOX-treated, allergen-challenged IL-15-overexpressing mice, which may be a novel pathway for restricting progression of pulmonary fibrosis. Taken together, our data establishes antifibrotic activity of IL-15 that might be a novel therapeutic molecule to combat the development of pulmonary fibrosis.

Early growth response-1 suppresses epidermal growth factor receptor-mediated airway hyperresponsiveness and lung remodeling in mice.

Transforming growth factor (TGF)-alpha and its receptor, the epidermal growth factor receptor, are induced after lung injury and are associated with remodeling in chronic pulmonary diseases, such as pulmonary fibrosis and asthma. Expression of TGF-alpha in the lungs of adult mice causes fibrosis, pleural thickening, and pulmonary hypertension, in addition to increased expression of a transcription factor, early growth response-1 (Egr-1). Egr-1 was increased in airway smooth muscle (ASM) and the vascular adventitia in the lungs of mice conditionally expressing TGF-alpha in airway epithelium (Clara cell secretory protein-rtTA(+/-)/[tetO](7)-TGF-alpha(+/-)). The goal of this study was to determine the role of Egr-1 in TGF-alpha-induced lung disease. To accomplish this, TGF-alpha-transgenic mice were crossed to Egr-1 knockout (Egr-1(ko/ko)) mice. The lack of Egr-1 markedly increased the severity of TGF-alpha-induced pulmonary disease, dramatically enhancing airway muscularization, increasing pulmonary fibrosis, and causing greater airway hyperresponsiveness to methacholine. Smooth muscle hyperplasia, not hypertrophy, caused the ASM thickening in the absence of Egr-1. No detectable increases in pulmonary inflammation were found. In addition to the airway remodeling disease, vascular remodeling and pulmonary hypertension were also more severe in Egr-1(ko/ko) mice. Thus, Egr-1 acts to suppress epidermal growth factor receptor-mediated airway and vascular muscularization, fibrosis, and airway hyperresponsiveness in the absence of inflammation. This provides a unique model to study the processes causing pulmonary fibrosis and ASM thickening without the complicating effects of inflammation.

Intracerebral infusion of an EGFR-targeted toxin in recurrent malignant brain tumors.

The purpose of this study is to determine the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and intracerebral distribution of a recombinant toxin (TP-38) targeting the epidermal growth factor receptor in patients with recurrent malignant brain tumors using the intracerebral infusion technique of convection-enhanced delivery (CED). Twenty patients were enrolled and stratified for dose escalation by the presence of residual tumor from 25 to 100 ng/ml in a 40-ml infusion volume. In the last eight patients, coinfusion of (123)I-albumin was performed to monitor distribution within the brain. The MTD was not reached in this study. Dose escalation was stopped at 100 ng/ml due to inconsistent drug delivery as evidenced by imaging the coinfused (123)I-albumin. Two DLTs were seen, and both were neurologic. Median survival after TP-38 was 28 weeks (95% confidence interval, 26.5-102.8). Of 15 patients treated with residual disease, two (13.3%) demonstrated radiographic responses, including one patient with glioblastoma multiforme who had a nearly complete response and remains alive >260 weeks after therapy. Coinfusion of (123)I-albumin demonstrated that high concentrations of the infusate could be delivered >4 cm from the catheter tip. However, only 3 of 16 (19%) catheters produced intraparenchymal infusate distribution, while the majority leaked infusate into the cerebrospinal fluid spaces. Intracerebral CED of TP-38 was well tolerated and produced some durable radiographic responses at doses

Perspectives on growth factors and orofacial development.

Despite the fact that orofacial clefts represent one of the most common birth defects, the molecular mechanisms by which the embryonic primordia of the midface grow and differentiate are not completely understood. A multiplicity of genes must be expressed and their protein products must interact in a highly orchestrated fashion to affect normal orofacial development. Several families of growth factors have emerged as key contributors to the choreography of cellular and tissue interactions contributing to morphogenesis of the orofacial region. This overview focuses on those growth factors that are generally accepted as playing a pivotal role in normal as well as abnormal development of first branchial arch-derived structures. Particular emphasis is given transforming growth factor-beta (TGF beta) and TGF alpha family members, as these have been the most extensively investigated with regard to their role in development of orofacial structures. Consideration is also given to evidence implicating developmental contributions from members of the bone morphogenetic protein and fibroblast growth factor families.

Phase I clinical study of the recombinant oncotoxin TP40 in superficial bladder cancer.

Transforming growth factor alpha-Pseudomonas exotoxin-40 (TP40) is a hybrid fusion protein that selectively binds to cancer cells that express the epidermal growth factor receptor. TP40 is then internalized and kills these cells by virtue of its Pseudomonas exotoxin-derived domains. We studied the safety and short-term antitumor activity of intravesical TP40 in 43 patients with refractory superficial bladder cancer. These patients had resected Ta/T1 disease (n = 19), visible Ta or T1 lesions (n = 11), or carcinoma in situ (n = 13). Patients were treated with increasing dose levels of TP40 at 0.15, 0.3, 0.6, 1.2, 2.4, 4.8, or 9.6 mg/week for 6 weeks and evaluated by comparing pretreatment and posttreatment cystoscopic examinations, cytology, and histopathology. All TP40 doses were well tolerated. No evidence of antitumor activity was seen in any of the patients with Ta or T1 lesions. However, 8 of 9 patients with evaluable carcinoma in situ were judged by histopathology of multiple biopsy specimens to exhibit clinical improvement following TP40 therapy. In most of these responsive patients, cystoscopic examination supported the histopathological findings, although cytology of urine and bladder washings persistently demonstrated malignant cells. Therefore, TP40 appears to be a well-tolerated biological agent that may prove to have utility in treating carcinoma in situ of the bladder.

Perinatal factors increase breast cancer risk.

Emerging evidence suggests that breast cancer may originate during early life. In particular, offspring of mothers who during pregnancy exhibited behaviors that are associated with increased incidence of breast cancer, may be at risk. These behaviors include intake of high fat diet or alcohol, or stressful life style. We have found that neonatal exposure to handling that leads to improved ability to cope with stress, reduces 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumors in rats. Further, our results indicate that maternal exposure to high fat diet increases the incidence of DMBA-induced mammary tumors in female offspring. High fat diet also increases serum 17 beta-estradiol (E2) levels in pregnant animals. These results support the hypothesis that in utero concentrations of estrogens play a critical role in the vulnerability to develop breast cancer. The mechanism of estrogen action might be related to its effect on the induction of epithelial hyperplasia and altered breast differentiation. These events then increase the rate of genetic/epigenetic changes that increase the possibility of neoplastic transformation. Increased pregnancy estrogens may also lead to behavioral alterations in the offspring. This could explain the proposed association between certain behavioral patterns and increased tumorigenity. Our results in transgenic mice overexpressing transforming growth factor alpha (TGF alpha) are in accordance with this interpretation. The male TGF alpha mice exhibit elevated serum E2 levels, impaired ability to cope with stress, increased voluntary alcohol intake and high incidence of spontaneous hepatocellular tumors. These findings indicate that animal models offer a unique opportunity to investigate the role of timing of risk behaviors on breast cancer. They are also useful in the attempts to understand the mechanism of early estrogen action on mammary tumorigenesis.