Intestinal macrophages and response to microbial encroachment

Macrophages in the gastrointestinal mucosa represent the largest pool of tissue macrophages in the body. In order to maintain mucosal homeostasis, resident intestinal macrophages uniquely do not express the lipopolysaccharide (LPS) co-receptor CD14 or the IgA (CD89) and IgG (CD16, 32, and 64) receptors, yet prominently display Toll-like receptors (TLRs) 3-9. Remarkably, intestinal macrophages also do not produce proinflammatory cytokines in response to TLR ligands, likely because of extracellular matrix (stromal) transforming growth factor-β (TGF-β) dysregulation of nuclear factor (NF)-κB signal proteins and, via Smad signaling, expression of IκBα, thereby inhibiting NF-κB-mediated activities. Thus, in noninflamed mucosa, resident macrophages are inflammation anergic but retain avid scavenger and host defense function, an ideal profile for macrophages in close proximity to gut microbiota. In the event of impaired epithelial integrity during intestinal infection or inflammation, however, blood monocytes also accumulate in the lamina propria and actively pursue invading microorganisms through uptake and degradation of the organism and release of inflammatory mediators. Consequently, resident intestinal macrophages are inflammation adverse, but when the need arises, they receive assistance from newly recruited circulating monocytes.

Mental health research with Latino farmworkers: a systematic evaluation of the short CES-D

Mental health research among Latino farmworkers is hampered by the absence of measurement evaluation that ensures farmworkers understand and can consistently and appropriately respond to questions about mental health. Cross-sectional data were obtained from 409 farmworkers via interviewer-administered survey questionnaires. Mental health was operationalized with the short-form Center for Epidemiologic Studies, Depression (CES-D) scale. The structured interviewer-administered survey questionnaires included measures to capture personal and work-related factors that could affect farmworkers' ability to understand and respond to mental health questions probed by the CES-D. Good variability in item response was observed across the 10 short-form CES-D items. There was no evidence of differential response across sub-groups of farmworkers for six of the 10 items. Responses to four of the 10 items differed by educational attainment, country of origin, and language preference. Overall, the internal consistency of the 10 items exceeded standard conventions, and observed differences in depressive symptoms were as expected. Researchers in farmworker mental health must remain attentive to the strength and validity of available measures for migrants, different ethnic groups and different socioeconomic backgrounds. Nevertheless, the overall pattern suggests that the CES-D is a viable tool for advancing farmworker mental health research.

Thermoelectric effect in single-molecule-magnet junctions

We study the spin-dependent thermoelectric transport through a single-molecule-magnet junction in the sequential tunneling regime. It is found that the intrinsic magnetic anisotropy of the single-molecule magnet can lead to gate-voltage-dependent oscillations of charge thermopower and a large violation of the Wiedeman-Franz law. More interestingly, the spin-Seebeck coefficient is shown to be greater than the charge-Seebeck coefficient, and a pure spin thermopower or/and a pure spin current can be obtained by tuning only the gate voltage. It needs neither an external magnetic field or irradiation of circularly polarized light on the molecule nor ferromagnetic leads to realize these interesting effects, indicating the powerful prospect of single-molecule-magnet applications in spintronic devices.

Operative outcomes using bevacizumab, docetaxel, and cisplatin as induction therapy in patients with operable lung cancer

7559

Background: Induction chemotherapy in patients with operable non-small cell lung cancer (NSCLC) is better tolerated than adjuvant chemotherapy. Bevacizumab improves survival in patients with advanced NSCLC; however its impact as an induction agent in patients undergoing lung resection is unknown. Here, we evaluated surgical outcomes in patients undergoing resection for NSCLC after induction therapy with bevacizumab (Bev), docetaxel (D) and cisplatin (C). Methods: Patients with stage IB-IIIA NSCLC, who could undergo resection with curative intent, were eligible for this phase II trial. None had squamous histology, large central tumors, or recent hemoptysis. All patients received up to 4 cycles of D 75 mg/m2 and C 75 mg/m2 and also received 3 cycles of Bev 15 mg/kg, followed by surgery. Two age and stage matched controls who received induction chemotherapy were selected per study patient. Fisher's exact tests compared pathologic stage, gender, and smoking history. Conditional logistic regression explored the association between clinical variables and outcomes in study versus control patients. Results: 30 patients received Bev-DC. Gender, smoking history, operative time, blood loss, and overall 30-day morbidity was similar between study and control patients. The 30 patients who received Bev-DC preoperatively had 12 complications vs 23 in the 60 controls. In the Bev-DC group there were 7 grade 3/4 complications (abscess (1), empyema (1), bronchopleural fistula (2), sigmoid volvulus (1), anastomotic dehiscence (1), GI bleed (1)) as compared to 2 in the control group (p=0.004). There were no deaths in the Bev-DC group and 2 among the controls. After controlling for age, gender and stage, patients in the study group had a trend towards increase incidence of overall complications (OR=3.89 (95%CI: 0.61–24.77) p=0.151). Conclusions: Although rates of 30-day morbidity were comparable, patients receiving Bev-DC induction had a higher incidence of grade 3/4 complications. There was no 30-day mortality among the patients receiving Bev-DC. Based on this interim analysis, patients receiving Bev-DC in the preoperative setting merit close monitoring.

[Table: see text]

Impact on disease-free survival of adjuvant erlotinib or gefitinib in patients with resected lung adenocarcinomas that harbor epidermal growth factor receptor (EGFR) mutations

7523

Background: Patients with stage IV adenocarcinoma whose tumors harbor EGFR mutations have high rates of response (∼ 75%) and prolonged progression free survival after EGFR tyrosine kinase inhibitor (TKI) treatment. Adjuvant cisplatin-based chemotherapy improves disease free survival (DFS) and overall survival (OS) in patients with resected stages IB-IIIA NSCLC. To see if adjuvant treatment with EGFR TKI (gefitinib or erlotinib) improves DFS in patients with EGFR mutation NSCLC, we conducted a retrospective review of patients with resected lung adenocarcinoma harboring EGFR mutations, some of whom received EGFR TKIs postoperatively. Methods: With Institutional Review Board approval, clinical information was obtained on all patients with stage I-III lung adenocarcinoma harboring EGFR exon 19 or 21 mutations that underwent resection at MSKCC between May 2002 and August 2008. Age, gender, type of surgery, histology, EGFR mutation status (exon 19 deletions and exon 21 L858R), stage, perioperative therapy and survival were recorded. Kaplan-Meier analysis and Cox regression analysis were performed. Results: We studied 150 patients (112 women, 38 men) with completely resected stage I-III lung adenocarcinoma whose resection specimens contained EGFR activating mutations in exon 19 or 21. Median age was 69. Forty two patients (28%) received cytotoxic chemotherapy. Forty eight (32%) received either erlotinib (n=26) or gefitinib (n=22) postoperatively. The median time on TKI was 16 months. The median DFS was 43 months in the group that received a TKI vs. 31 months for those that did not. After controlling for stage, individuals who received adjuvant gefitinib or erlotinib had a better DFS (HR=0.38, 95%CI: 0.16–0.90) than the non-TKI group (p=0.03). The median overall survival has not been reached. Conclusions: These data indicate that the adjuvant use of either gefitinib or erlotinib improves DFS in patients with completely resected stage I -III lung adenocarcinomas with mutations in EGFR exons 19 and 21. These data justify a randomized trial in similar patients.

[Table: see text]

Phase II study of bevacizumab (B) plus cisplatin (C) plus intensity-modulated radiation therapy (IMRT) for locoregionally advanced head and neck squamous cell cancer (HNSCC): Preliminary results

6013

Background: For patients with locoregionally advanced HNSCC, concurrent high-dose cisplatin + radiation therapy is a historical standard of care. HNSCC tumors expressing high levels of VEGF have been associated with worse prognosis, and bevacizumab may sensitize tumors to cisplatin and radiation. Methods: Percutaneous gastrostomy (PEG) tube was placed pre-treatment for all patients. Planned treatment consisted of definitive IMRT (total, 70 Gy) with concurrent C (50 mg/m2 days 1, 2, 22, 23, 43, 44) and B (15 mg/kg days 1, 15, and 43). The initial version of the protocol called for an additional 6 months of maintenance B, but this was discontinued in an amendment after a G4 pulmonary hemorrhage event in subject 1 during maintenance treatment. 1o endpoint was 2-year PFS. Results: 42 previously untreated patients (34 M, 8 F), median age 55 (27–75), with stage III/IV, M0 HNSCC (oropharynx 39, larynx 3) enrolled. HPV status by ISH: 16 pos, 14 neg, 12 unknown). All patients have completed treatment. CTCAE v3.0 toxicities (% patients) have included: functional mucositis G3 (76 %); nausea G3 (24%); vomiting G3 (17%); neutropenia G3 (31%), G4 (10%); hemoglobin G3 (17%); hyponatremia G3 (14%). Median weight loss during treatment was 8.9 kg (2.1–26 kg). There were two deaths within 90 days of last treatment: 1 aspiration pneumonia, 1 sudden death. Median follow up is approximately 9 months (range, <3 to 24 months). Locoregional control rate is 100%. Three patients have developed distant metastasis. Estimated one-year PFS is 83% (± 10%) and estimated 1 year OS is 88% (± 6%). At a median of 8 months after completion of radiation therapy, PSS-HN scores were 100 for eating, speech, and diet in respectively 88%, 76%, and 53% of surveyed patients (n = 17). Conclusions: The addition of B to C + IMRT did not appear to increase toxicity to unacceptable levels, and preliminary efficacy results are encouraging.

[Table: see text]

Phase I study of everolimus (E; RAD001) + low-dose weekly cisplatin (C) for patients with advanced solid tumors: Preliminary results

e14527

Background: Preclinical studies demonstrate synergistic anti-tumor activity with the combination of E + C. Methods: Patients received E per oral for days 1–21 of a 28 day cycle. E was dose escalated though 4 planned dose levels (DLs): 2.5 mg/day, 5 mg/day, 7.5 mg/day, and 10 mg/day. Cisplatin dose was fixed at 20 mg/m2 intravenously on days 1, 8, 15. A standard 3 + 3 dose escalation scheme was used. Blood samples for pharmacokinetics were collected on Day 1 and Day 8 of Cycle 1. Response was assessed by RECIST after 2 cycles. Results: 24 patients enrolled: 13 M, 11F; median age 62 (32–77); median number of prior cytotoxic chemotherapy regimens 1 (0–3; 75% with prior RT). At DL1, 3 patients were inevaluable (1 withdrawal of consent prior to treatment, 1 disease progression during cycle 1, 1 recurrent diverticulitis during cycle 1) and were replaced. DL 1 was expanded after a patient with melanoma metastatic to liver had sudden death of unclear cause, and the protocol was amended to exclude patients with hepatic dysfunction. At DL2, one patient experienced grade 3 small bowel obstruction of uncertain etiology, and the dose level was expanded to 6 evaluable patients without additional DLT. No DLTs occurred at DL3. No DLTs have occurred to date among 6 patients enrolled at DL 4. Adverse events per cycle (total n = 63 cycles; 20 patients evaluable for toxicity) include: lymphopenia G3 (19%), AST G3 (3.2%), alkaline phosphatase G3 (3.2%), ALT G3 (1.6%), hyponatremia (1.6%). Median cycles per patient, 2 (range <1 to 10+). Minor response seen in pulmonary carcinoid (n = 1); prolonged SD ≥ 6 cycles seen in pulmonary carcinoid (n=2), basal cell carcinoma (n=1), and esthesioneuroblastoma (n=1). Conclusions: Pending safety analysis at the final planned dose level, the phase II recommended dose is E 10 mg/day (days 1 - 21) + C 20 mg/m2 (days 1, 8, and 15) on a 28-day cycle.

[Table: see text]

Modulation of 11beta-hydroxysteroid dehydrogenase expression by bombesin: a possible mechanism for glucocorticoid resistance in androgen independent prostate cancer

Treatment with glucocorticoids is one of a limited number of options for androgen independent prostate cancer. Neuroendocrine differentiation has been shown to contribute to androgen-independent prostate cancer progression. To study the potential link between neuroendocrine differentiation and the glucocorticoid action, we investigated the effects of the product of neuroendocrine differentiation--bombesin on glucocorticoid metabolizing enzymes--11beta-hydroxysteroid dehydrogenases in PC-3 cells. Our Western analysis, RT-PCR, and activity assays demonstrate that while 18-hour exposure to bombesin reduces 11beta-hydroxy-steroid dehydrogenases-1 profiles (activities 25% less, protein level 29% lower, mRNA levels 45% lower), contrarily it increases 11beta-hydroxysteroid dehydrogenases-2 profiles (activities 34%, protein levels 100%, mRNA levels 120%). Blockade bombesin action with bombesin receptor antagonists and the enzyme degrading bombesin prevented these changes, suggesting the observed modulations were bombesin receptor-specific. In addition, bombesin increased the amounts of interleukin-8 and mRNA of vascular endothelial growth factor receptor 2, which were lowered in the presence of cortisol, suggesting that neuropeptide blockade may extend the benefits of glucocorticoids in treating androgen-independent prostate cancer.

The DIURNAL project: DIURNAL and circadian expression profiling, model-based pattern matching, and promoter analysis

The DIURNAL project ( http://diurnal.cgrb.oregonstate.edu/ ) provides a graphical interface for mining and viewing diurnal and circadian microarray data for Arabidopsis thaliana, poplar, and rice. The database is searchable and provides access to several user-friendly Web-based data-mining tools with easy-to-understand output. The associated tools include HAYSTACK ( http://haystack.cgrb.oregonstate.edu/ ) and ELEMENT ( http://element.cgrb.oregonstate.edu/ ). HAYSTACK is a model-based pattern-matching algorithm for identifying genes that are coexpressed and potentially coregulated. HAYSTACK can be used to analyze virtually any large-scale microarray data set and provides an alternative method for clustering microarray data from any experimental system by grouping together genes whose expression patterns match the same or similar user-defined patterns. ELEMENT is a Web-based program for identifying potential cis-regulatory elements in the promoters of coregulated genes in Arabidopsis, poplar, and rice. Together, DIURNAL, HAYSTACK, and ELEMENT can be used to facilitate cross-species comparisons among the plant species supported and to accelerate functional genomics efforts in the laboratory.

Circulating tumor cells (CTC): Assessment of treatment efficacy in metastatic breast cancer (MBC)

10535

Background: Preliminary data in MBC suggest that ≥5 CTC/7.5 mL blood is associated with worse progression free survival (PFS) and overall survival (OS), and that the persistence of ≥5 CTC/7.5 mL blood after the initiation of therapy predicts for treatment failure (NEJM 2004. 351:781.). We are conducting a prospective clinical research study to validate the prognostic and predictive significance of this serum biomarker in MBC. Methods: Serial CTC levels are obtained in patients starting a new systemic treatment regimen for progressive, radiographically measurable MBC. 10 mL samples of peripheral blood are collected before the start of treatment and then at 3–4 week intervals. All subjects are followed prospectively for PFS and OS, and they are offered the opportunity to continue CTC testing upon disease progression. CTC enumeration is performed on a 7.5 mL blood volume using the CellSearch technology (Veridex, LLC; Warren, NJ). Epithelial cells are immunomagnetically separated and fluorescently labeled, and nucleated (DAPI+) cells with the EpCAM+, cytokeratin 8/18/19+, and CD45- phenotype are counted as CTC. Clinical outcomes are based on radiographic studies and physical examination in accordance with RECIST criteria. Results: 46 of 100 subjects have been accrued, and 33 have completed at least one radiographic staging evaluation with a median follow up of 7 mos (range 2–18 mos). Treatment for the 33 evaluable patients includes chemotherapy (27%), endocrine therapy (46%), and combination therapy with a biologic agent (27%). At baseline, 85% (28/33) had at least 1 CTC/7.5 mL (range 1–78), and 27% (9/33) had ≥5 CTC/7.5 mL. Median PFS was 2.57 months and 6.77 months for subjects with ≥5 vs <5 CTC/7.5 mL at baseline, respectively (p=0.02). Conclusions: The current data validate the observation that baseline CTC levels correlate with PFS in patients with MBC and measurable disease. Patient accrual and data analysis are ongoing to confirm that persistent CTC levels ≥5/7.5 mL correlate with a lack of treatment efficacy and therefore are a reliable surrogate marker of disease responsiveness and PFS.

[Table: see text]

A phase I trial of RX-0201 (AKT anti-sense) in patients with an advanced cancer

3564

Background: Akt-1, a proto-oncogene, plays a vital role in cancer progression by stimulating proliferation and inhibiting apoptosis of cancer cells. RX-0201, a 20-mer oligonucleotide with sequence complementary to Akt-1 mRNA, is designed to inhibit the expression of Akt-1 within cancer cells in cancer patients (pts). Non-clinical studies conducted on RX-0201 demonstrated that RX-0201 bears significant in vitro and in vivo anti-cancer activities with favorable safety. Purposes: The aims of the current phase I trial were to determine the maximum tolerated dose (MTD) and to establish pharmacokinetic (PK) and safety profiles of RX-0201 in pts with an advanced cancer. Methods: RX-0201 was administered to pts with an advanced cancer by up to 2 cycles of continuous infusion; each cycle of infusion lasted for 14 days which was followed by a 7-day rest. Rapid dose escalation had been used until at least a grade (G) 2 toxicity was observed, and then a traditional dose escalation followed. Entry criteria included Karnofsky Performance Status score =70, advanced cancer, tumor accessible for paired biopsy, and signed informed consent. 17 pts were enrolled and treated at a dose level ranging from 6 to 315 mg/m2/d on D1–14, repeated q 21 d. Results: G 3 fatigue was observed in two pts at the 315 mg/m2/d dose; three pts dosed at 250 mg/m2/d were not noted with any G 3 toxicity, which make this dose (250 mg/m2/d) the recommended phase II trial dose. No other significant, compound-related, adverse events were observed in those 17 pts participated. Pts PK profiles of RX-0201 and AKT-1 immunohistochemistry results on pts’ tumor biopsy samples will also be presented. Conclusion: MTD of RX-0201 is 315 mg/m2/d in pts with an advanced cancer when the compound is administered in the current continuous infusion regimen.

No significant financial relationships to disclose.

Neutral endopeptidase inhibits prostate cancer tumorigenesis by reducing FGF-2-mediated angiogenesis

Neutral endopeptidase (NEP) is a cell surface peptidase that catalytically inactivates a variety of physiologically active peptides including basic fibroblast growth factor (FGF-2). We investigated the effect of using lentivirus to overexpress NEP in NEP-deficient DU145 prostate cancer cells. Third-generation lentiviral vectors encoding wild-type NEP (L-NEP), catalytically inactive mutant NEP (L-NEPmu), and green fluorescent protein (L-GFP) were stably introduced into DU145 cells. FGF-2 levels in cell culture supernatants decreased by 80% in L-NEP-infected DU145 cells compared to cells infected with L-NEPmu or L-GFP (P<0.05) while levels of other angiogenic factors were not altered. In vitro tubulogenesis of human vascular endothelial cells induced by conditioned media from DU145 cells infected with L-NEP was significantly reduced compared with that from DU145 cells infected with L-GFP (P<0.05). Tumor xenografts from L-NEP-infected DU145 cells were significantly smaller compared to control cell xenografts and vascularity within these tumors was decreased (P<0.05). Our data suggest that stable expression of NEP in DU145 cells inhibits prostate cancer tumorigenicity by inhibiting angiogenesis, with a probable mechanism being proteolytic inactivation of FGF-2.

The role of double-balloon enteroscopy in diagnosis and management of incomplete small-bowel obstruction

BACKGROUND AND STUDY AIMS

Double-balloon enteroscopy (DBE) is a newly developed endoscopic technique for investigating various small-bowel diseases. The aim of this study was to evaluate the diagnostic yield and therapeutic impact of DBE in patients with incomplete small-bowel obstruction (SBO).

PATIENTS AND METHODS

This study is a prospective analysis of 45 consecutive patients specifically referred to our hospital between December 2004 and January 2006 for investigation of incomplete SBO that had been confirmed by both clinical symptoms and imaging tests. Patients with a high suspicion of postoperative adhesion were excluded and DBE was performed in stable patients. The final management was guided by the results of DBE and radiographic studies. Demographic, clinical, procedural, and outcome data were collected for analysis.

RESULTS

A total of 30 DBEs were performed in 29 patients (11 women, 18 men; mean age 52.0 +/- 13.5 years). DBE identified causes of incomplete SBO in 27 patients (93.1%) and allowed histopathologic evaluation in 17 patients (58.6%). The more common abnormalities detected were small-bowel tumors (48.3%) and strictures caused by Crohn's disease (24.1%). In detecting small-bowel abnormalities, DBE showed a sensitivity of 96.4%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 50%. DBE influenced the therapeutic strategy in 41.4% of patients by adding more information regarding appropriate treatment. Follow-up data were obtained for 26 patients (89.7%), for a mean 9.4 months (range 4-18 months). Of the 26 patients with follow-up, 21 (72.4%) had no further SBO.

CONCLUSIONS

Double-balloon enteroscopy is a feasible diagnostic tool for detecting the causes of incomplete SBO in patients without a history of abdominal surgery and also influences therapy in patients without a definite cause detected by conventional radiography.

Advantages and challenges of using census and multiplier methods to estimate the number of female sex workers in a Chinese city

Using census and multiplier methods to estimate the size of the population of female sex workers (FSWs) in a small city in western China, this study compared the advantages and challenges of the two methods. It was estimated that there were about 1,500 FSWs within the urban area using the census method, which was significantly lower than that estimated by the multiplier method (2,500). Each method has advantages and limitations, and could be applied to different situations. The census method is less time and resource consuming in smaller regions and has a tendency to underestimate, and therefore, the result can be viewed as a low limit. It is useful in a local setting, for example, when estimations are needed for planning HIV/AIDS prevention programmes in a single city. Using existing information or resources, multiplier method could be used to produce estimates for a large geographic area or at a national level.

Lentiviral vector neutral endopeptidase gene transfer suppresses prostate cancer tumor growth

Neprilysin (neutral endopeptidase, NEP) is a cell surface peptidase whose expression is lost in approximately 50% of prostate cancers (PC). NEP normally functions to inactivate peptides such as bombesin and endothelin-1, and potentiates the effects of the PTEN tumor suppressor via a direct protein-protein interaction. NEP loss contributes to PC progression. We investigated the therapeutic efficacy of using a lentiviral vector system to restore NEP expression in PC cells. Third-generation lentiviral vectors encoding wild-type NEP (L-NEP) or green fluorescent protein (L-GFP) were introduced into NEP-deficient 22RV1 PC cells. Cells infected with L-NEP or L-GFP at a multiplicity of infection of 10 demonstrated NEP enzyme activity of 1171.2+/-4.9 and 17.2+/-5.3 pmol/microg/min (P<0.0001), respectively. Cell viability, proliferation and invasion were each significantly inhibited in 22RV1 cells expressing NEP compared with control cells infected with L-GFP (P<0.01). Analysis of known downstream effects of NEP showed NEP-expressing cells exhibiting decreased Akt and focal adhesion kinase phosphorylation and increased PTEN protein expression. Finally, injection of L-NEP into established 22RV1 xenograft tumors significantly inhibited tumor growth (P<0.01). These experiments demonstrate that lentiviral NEP gene transfer is a novel targeted strategy for the treatment of NEP-deficient PC.

Activation of p300 histone acetyltransferase activity and acetylation of the androgen receptor by bombesin in prostate cancer cells

Androgen receptor signaling in prostate cancer cells is augmented by the androgen receptor (AR) coactivator p300, which transactivates and acetylates the AR in the presence of dihydrotestosterone (DHT). As prostate cancer (PC) cells progress to androgen independence, AR signaling remains intact, indicating that other factors stimulate AR activities in the absence of androgen. We previously reported that neuropeptide growth factors could transactivate the AR in the presence of very low concentrations of DHT. Here, we examine the involvement of p300 in neuropeptide activation of AR signaling. Transfection of increasing concentrations of p300 in the presence of bombesin into PC-3 cells resulted in a linear increase in AR transactivation, suggesting that p300 acts as a coactivator in neuropeptide-mediated AR transactivation. P300 is endowed with histone acetyltransferase (HAT) activity. Therefore, we examine the effect of bombesin on p300 HAT activity. At 4 h after the addition of bombesin, p300 HAT activity increased 2.0-fold (P<0.01). Incubation with neutral endopeptidase, which degrades bombesin, or bombesin receptor antagonists blocked bombesin-induced p300 HAT activity. To explore the potential signaling pathways involved in bombesin-induced p300 HAT activity, we examined Src and PKCdelta pathways that mediate bombesin signaling. Inhibitors of Src kinase activity or Src kinase siRNA blocked bombesin-induced p300 HAT activity, whereas PKCdelta inhibitors or PKCdelta siRNA significantly increased bombesin-induced p300 HAT activity suggesting that Src kinase and PKCdelta kinase are involved in the regulation of p300 HAT activity. As AR is acetylated in the presence of 100 nM DHT, we next examined whether bombesin-induced p300 HAT activity would result in enhanced AR acetylation. Bombesin-induced AR acetylation at the same motif KLKK observed in DHT-induced acetylation. Elimination of p300 using p300 siRNA reduced AR acetylation, demonstrating that AR acetylation was mediated by p300. AR acetylation results in AR transactivation and the expression of the AR-regulated gene prostate-specific antigen (PSA). Therefore, we examined bombesin-induced AR transactivation and PSA expression in the presence and absence of p300 siRNA and found inhibition of p300 expression reduced bombesin-induced AR transactivation and PSA expression. Together these results demonstrate that bombesin, via Src and PKCdelta signaling pathways, activates p300 HAT activity which leads to enhanced acetylation of AR resulting in increased expression of AR-regulated genes.

Neuropeptide-stimulated cell migration in prostate cancer cells is mediated by RhoA kinase signaling and inhibited by neutral endopeptidase

The neuropeptides bombesin and endothelin-1 stimulate prostate cancer (PC) cell migration and invasion (J Clin Invest, 2000; 106: 1399-1407). The intracellular signaling pathways that direct this cell movement are not well delineated. The monomeric GTPase RhoA is required for migration in several cell types including neutrophils, monocytes and fibroblasts. We demonstrate that bombesin-stimulated PC cell migration occurs via the heterotrimeric G-protein-coupled receptors (G-protein) G alpha 13 subunit leading to activation of RhoA, and Rho-associated coiled-coil forming protein kinase (ROCK). Using siRNA to suppress expression of the three known G-protein alpha-subunit-associated RhoA guanine nucleotide exchange factors (GEFs), we also show that two of these RhoA GEFs, PDZ-RhoGEF and leukemia-associated RhoGEF (LARG), link bombesin receptors to RhoA in a non-redundant manner in PC cells. We next show that focal adhesion kinase, which activates PDZ-RhoGEF and LARG, is required for bombesin-stimulated RhoA activation. Neutral endopeptidase (NEP) is expressed on normal prostate epithelium whereas loss of NEP expression contributes to PC progression. We also demonstrate that NEP inhibits neuropeptide activation of RhoA. Together, these results establish a contiguous signaling pathway from the bombesin receptor to ROCK in PC cells, and they implicate NEP as a major regulator of neuropeptide-stimulated RhoA in these cells. This work also identifies members of this signaling pathway as potential targets for rational pharmacologic manipulation of neuropeptide-stimulated migration of PC cells.

Effects of testosterone replacement in human immunodeficiency virus-infected women with weight loss

The objective of this study was to determine whether physiological testosterone replacement increases fat-free mass (FFM) and muscle strength and contributes to weight maintenance in HIV-infected women with relative androgen deficiency and weight loss. Fifty-two HIV-infected, medically stable women, 18-50 yr of age, with more than 5% weight loss over 6 months and testosterone levels below 33 ng/dl were randomized into this double-blind, placebo-controlled trial of 24-wk duration. Subjects in the testosterone group applied testosterone patches twice weekly to achieve a nominal delivery of 300 mug testosterone over 24 h. Data were evaluable for 44 women. Serum average total and peak testosterone levels increased significantly in the testosterone group, but did not change in the placebo group. However, there were no significant changes in FFM (testosterone, 0.7 +/- 0.4 kg; placebo, 0.3 +/- 0.4 kg), fat mass (testosterone, 0.3 +/- 0.7 kg; placebo, 0.6 +/- 0.7 kg), or body weight (testosterone, 1.0 +/- 0.9 kg; placebo, 0.9 +/- 0.8 kg) between the two treatment groups. There were no significant changes in leg press strength, leg power, or muscle fatigability in either group. Changes in quality of life, sexual function, cognitive function, and Karnofsky performance scores did not differ significantly between the two groups. High-density lipoprotein cholesterol levels decreased significantly in the testosterone group. The patches were well tolerated. We conclude that physiological testosterone replacement was safe and effective in raising testosterone levels into the mid to high normal range, but did not significantly increase FFM, body weight, or muscle performance in HIV-infected women with low testosterone levels and mild weight loss. Additional studies are needed to fully explore the role of androgens in the regulation of body composition in women.

Prenatal ethanol exposure alters the postnatal development of the spontaneous electrical activity of dopamine neurons in the ventral tegmental area

Prenatal ethanol exposure causes a persistent reduction in the spontaneous electrical activity of dopamine (DA) neurons in the ventral tegmental area (VTA) in adult animals. Because DA neuron activity matures into adult pattern during postnatal development, it is possible that reduced activity in VTA DA neurons after prenatal ethanol exposure is caused by impaired postnatal development. This possibility was investigated in the present study using the in vivo extracellular single-unit recording and brain stimulation techniques. The results show an age-dependent decrease in the number of spontaneously active VTA DA neurons from 2 to 4 weeks of age in both the control and prenatal ethanol-exposed animals. In ethanol-exposed animals, the age-dependent decrease was more prominent after 3 weeks of age, resulting in lower numbers of spontaneously active VTA DA neurons in 4-week-old and adult animals. In both the control and ethanol-exposed animals, there were age-dependent increases in the firing rates and burst firing activity of VTA DA neurons after 2 weeks of age. Ethanol exposure led to slightly lower firing rates in 4-week-old and adult animals and did not impact the burst firing pattern in any age groups. There were no changes in axon conduction velocity and antidromic spike characteristics of VTA DA neurons. These results indicate that reduced activity of VTA DA neurons during adulthood after prenatal ethanol exposure does not begin prenatally. Instead, it is a result of impaired postnatal development manifested only when animals reach 4 weeks of age. These results suggest that early intervention may be an effective treatment strategy for attention deficit/hyperactivity disorder, a behavioral dysfunction related to the abnormalities of DA systems and often observed in children with fetal alcohol spectrum disorder.

Testosterone dose-response relationships in healthy young men

Testosterone increases muscle mass and strength and regulates other physiological processes, but we do not know whether testosterone effects are dose dependent and whether dose requirements for maintaining various androgen-dependent processes are similar. To determine the effects of graded doses of testosterone on body composition, muscle size, strength, power, sexual and cognitive functions, prostate-specific antigen (PSA), plasma lipids, hemoglobin, and insulin-like growth factor I (IGF-I) levels, 61 eugonadal men, 18-35 yr, were randomized to one of five groups to receive monthly injections of a long-acting gonadotropin-releasing hormone (GnRH) agonist, to suppress endogenous testosterone secretion, and weekly injections of 25, 50, 125, 300, or 600 mg of testosterone enanthate for 20 wk. Energy and protein intakes were standardized. The administration of the GnRH agonist plus graded doses of testosterone resulted in mean nadir testosterone concentrations of 253, 306, 542, 1,345, and 2,370 ng/dl at the 25-, 50-, 125-, 300-, and 600-mg doses, respectively. Fat-free mass increased dose dependently in men receiving 125, 300, or 600 mg of testosterone weekly (change +3.4, 5.2, and 7.9 kg, respectively). The changes in fat-free mass were highly dependent on testosterone dose (P = 0.0001) and correlated with log testosterone concentrations (r = 0.73, P = 0.0001). Changes in leg press strength, leg power, thigh and quadriceps muscle volumes, hemoglobin, and IGF-I were positively correlated with testosterone concentrations, whereas changes in fat mass and plasma high-density lipoprotein (HDL) cholesterol were negatively correlated. Sexual function, visual-spatial cognition and mood, and PSA levels did not change significantly at any dose. We conclude that changes in circulating testosterone concentrations, induced by GnRH agonist and testosterone administration, are associated with testosterone dose- and concentration-dependent changes in fat-free mass, muscle size, strength and power, fat mass, hemoglobin, HDL cholesterol, and IGF-I levels, in conformity with a single linear dose-response relationship. However, different androgen-dependent processes have different testosterone dose-response relationships.

Suppression of matrix metalloproteinase-2 gene expression and invasion in human glioma cells by MMAC/PTEN

Human gliomas are highly invasive, and remain to be a major obstacle for any effective therapeutic remedy. Among many other factors, gliomas express elevated levels of matrix metalloproteinases (MMPs), which have been implicated to play an important role in tumor invasion as well as neovascularization. The tumor suppressor gene mutated in multiple advanced cancers/phosphatase and tensin homologue (MMAC/PTEN) has been shown to inhibit cell migration, spreading, and focal adhesion. In this study, we determined whether MMAC/PTEN inhibits tumor invasion by modulating MMP-2 activity. Our results showed that reintroduction of the MMAC/PTEN gene into human glioma U251 and U87 cells modified their phenotype and growth characteristics. The ability of MMAC/PTEN to induce anoikis in U251 cells was accompanied by a significant inhibition of in vitro invasion (70%). Expression of MMAC/PTEN in U251 and U87 cells inhibited MMP-2 enzymatic activity as determined by zymography. Furthermore, MMAC/PTEN expression strongly decreased MMP-2 mRNA levels, which correlated well with the inhibition of invasion capacity in these cells. Concomitant with MMP-2 expression and activity, MMP-2 promoter activity was also reduced in MMAC/PTEN expressing cells. Our observations suggest that MMAC/PTEN inhibits tumor cell invasion in part by regulating MMP-2 gene transcription and thereby its enzymatic activity. Further characterization of this regulation will facilitate the development of MMAC/PTEN based gene therapy for gliomas.

6-Substituted-4-(3-bromophenylamino)quinazolines as putative irreversible inhibitors of the epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor (HER-2) tyrosine kinases with enhanced antitumor activity

A series of new 6-substituted-4-(3-bromophenylamino)quinazoline derivatives that may function as irreversible inhibitors of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor (HER-2) tyrosine kinases have been prepared. These inhibitors have, at the C-6 position, butynamide, crotonamide, and methacrylamide Michael acceptors bearing water-solublilizing substituents. These compounds were prepared by acylation of 6-amino-4-(3-bromophenylamino)quinazoline with unsaturated acid chlorides or mixed anhydrides. We show that attaching a basic functional group onto the Michael acceptor results in greater reactivity, due to intramolecular catalysis of the Michael addition and/or an inductive effect of the protonated basic group. This, along with improved water solubility, results in compounds with enhanced biological properties. We present molecular modeling and experimental evidence that these inhibitors interact covalently with the target enzymes. One compound, 16a, was shown to have excellent oral activity in a human epidermoid carcinoma (A431) xenograft model in nude mice.

Distribution and mobility of aluminium in an Al-accumulating plant, Fagopyrum esculentum Moench

Buckwheat (Fagopyrum esculentum Moench. cv. Jianxi) accumulates high concentrations of Al in the leaves without showing any toxicity. To understand the accumulation mechanism of Al in buckwheat, the distribution and mobility of Al in buckwheat were investigated. Relatively long-term treatment (28 d) with Al led to a decrease in Al concentration from old to young leaves, while a short-term (1 d) exposure to Al resulted in a uniform distribution of Al in the leaves. When the fourth leaf was wrapped inside a transparent plastic bag to suppress transpiration, the Al concentration of this leaf was only one-quarter of that in the corresponding leaf without wrapping. Within a leaf, the Al concentration at the margins was much higher than that in the centre. These results indicate that Al distribution in the leaves is controlled by both rate and duration of transpiration. The mobility of Al between old and new leaves was studied by first growing plants in a solution with Al, followed by culture in a solution without Al. The Al content in the two new leaves appeared after removal of external Al was very low, whereas that in the old leaves did not decrease but continued to increase. The increased Al content was found to be translocated from Al remaining in the roots. It is concluded that Al is not mobile once it is accumulated in the leaf.

A comparison of whole wheat, refined wheat and wheat bran as inhibitors of heterocyclic amines in the Salmonella mutagenicity assay and in the rat colonic aberrant crypt focus assay

Refined wheat, unrefined whole wheat, and wheat bran were studied for their ability to protect against heterocyclic amines (HCAs) in vitro and in vivo. Wheat bran, which binds HCAs in vitro, as well as refined wheat and unrefined whole wheat, inhibited the mutagenic activities of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) when they were co-incubated and the supernatant (minus grain) was added to the Salmonella assay. The water-soluble fraction alone from refined and unrefined wheat, but not bran, also inhibited against these mutagens in vitro. In vivo, AIN-93G diets containing refined wheat or unrefined wheat were examined for their ability to inhibit IQ-induced colonic aberrant crypt foci (ACF) in the Fischer 344 rat. A slight increase in the number of AC/ACF (aberrant crypts/ACF) was seen after 16 weeks in rats treated post-initiation with refined wheat (P < 0.05), and fewer foci with two or three aberrant crypts (ACF-2) were found in rats given unrefined whole wheat post-initiation compared with animals treated with the same diet during the initiation phase (P < 0.05). There was no significant difference in the profile of IQ urinary metabolites or excretion of promutagens 0-48 h after carcinogen dosing, and grains had no effect on hepatic cytochrome P4501A1 (CYP1A1), CYP1A2, aryl sulfotransferase or N-acetyltransferase activities; however, a slightly higher UDP-glucuronosyl transferase activity was observed in rats fed unrefined wheat compared with refined wheat diets (P < 0.05). Thus, despite their antimutagenic activities in vitro, only marginal effects were seen with refined and unrefined wheat in vivo with respect to hepatic enzyme activities, carcinogen metabolism and IQ-induced ACF in the rat colon.

Pharmacokinetics of a transdermal testosterone system in men with end stage renal disease receiving maintenance hemodialysis and healthy hypogonadal men

Androgen deficiency is common in men with end stage renal disease (ESRD) on maintenance hemodialysis. Pharmacokinetics of transdermal testosterone in men receiving maintenance hemodialysis have not been studied. Our objective was to compare the pharmacokinetics of a transdermal testosterone system in healthy hypogonadal men and in men with ESRD on maintenance hemodialysis. We recruited 10 healthy hypogonadal men and 8 medically stable men on maintenance hemodialysis, 18--70 yr old, who had serum testosterone less than 300 ng/dL. After baseline sampling during a 24-h control period, two testosterone patches were applied daily for 28 days, to achieve a nominal delivery of 10-mg testosterone daily. In addition to single, pooled samples on days 7, 14, and 21, blood was drawn at 0, 2, 4, 6, 8, and 24 h on day 28 in healthy hypogonadal men and on an interdialytic day (day 21 or 28) as well as a dialysis day (day 21 or 28) in men on hemodialysis. On the dialysis day (day 21 or 28), serum free and total testosterone levels were measured hourly for 4 h before hemodialysis and for 4 h during hemodialysis. The dialysate was sampled for testosterone measurement. Baseline mean + SD total (92 +/- 82 vs. 222 +/- 50 ng/dL) and free (11 +/- 9 vs. 27 +/- 6 pg/mL) testosterone concentrations were lower in healthy hypogonadal men than in men with ESRD. After application of two testosterone patches, serum total and free testosterone concentrations rose into the midnormal range in both groups of men. Time-average, steady state (total testosterone, 506 +/- 88 vs. 516 +/- 86 ng/dL; free testosterone, 55 +/- 9 vs. 67 +/- 11 pg/mL), minimum, and maximum total and free testosterone concentrations were not significantly different between the two groups of men during treatment. Increments in total and free testosterone concentrations above baseline, baseline-subtracted areas under the total and free testosterone curves, and half-life of testosterone elimination (t(1/2), 2.1 +/- 0.1 vs. 2.1 +/- 0.2 h, P = not significant) were not significantly different between the two groups. In men receiving hemodialysis, time-average, steady state, and maximal total and free testosterone concentrations and baseline-subtracted areas under the total and free testosterone curves were higher on dialysis day than on an interdialytic day. On the day of hemodialysis, time-average total and free testosterone concentrations were not significantly different during the 4 h before or during hemodialysis. The amount of testosterone removed in the dialysate (8.4 +/- 1.6 microg during 4 h of hemodialysis) was small compared with the daily testosterone production rates in healthy young men. Serum dihydrotestosterone and estradiol concentrations increased into the normal male range and were not significantly different between the two groups. Percent suppression of LH was greater in men with ESRD than in healthy hypogonadal men. A regimen of two Testoderm TTS testosterone patches (Alza Corp., Mountain View, CA) daily can maintain serum concentrations of total and free testosterone and its metabolites dihydrotestosterone and estradiol in the midnormal range in healthy hypogonadal men and men on hemodialysis. The amount of testosterone cleared by hemodialysis is small, and hemodialysis does not significantly affect serum total and free testosterone concentrations in men treated with the testosterone patch.

Tumor-suppressive effects of neutral endopeptidase in androgen-independent prostate cancer cells

Expression of neutral endopeptidase (NEP) 24.11 is diminished in metastatic, androgen-independent prostate cancers (PCs; C. N. Papandreou et al., NAT: MED:, 4: 50--57, 1998). To determine the effects on androgen-independent PC cells of overexpressing cell-surface NEP, an inducible tetracycline-regulatory gene expression system was used to stably introduce and express the NEP gene in androgen-independent TSU-Pr1 cells generating WT-5 cells, which expressed high levels of enzymatically active NEP protein when cultured in the absence of tetracycline. TN12 cells, which contain the identical vectors without the NEP gene and do not express NEP, were used as control. Expression of NEP in WT-5 cells after removal of tetracycline from the media resulted in a >80% inhibition in cell proliferation over a 1-week period (P < 0.005) compared with control cells. Tumor formation occurred in the prostate glands of orthotopically injected athymic mice killed at 30 days in 4 of 5 mice that were given injections of 2 x 10(6) WT-5 cells and were fed doxycycline (NEP suppressed), and in all mice that were given injections of TN12 cells and were fed with or without doxycycline. In contrast, only 1 of 5 mouse prostates developed a tumor in mice that were given injections of WT-5 cells and that did not receive doxycycline. Analysis of the mechanisms of NEP-induced growth suppression revealed that NEP expression in WT-5 cells induced a 4-fold increase in the number of PC cells undergoing apoptosis, and increased the expression of p21 tumor suppressor gene protein and the level of unphosphorylated retinoblastoma protein as determined by Western blot. Flow cytometric analysis show that induced NEP expression in WT-5 cells resulted in a G(1) cell cycle arrest. These data show that NEP can inhibit PC cell growth and tumorigenicity and suggest that NEP has potential as therapy for androgen-independent PC.

Neutral endopeptidase inhibits neuropeptide-mediated transactivation of the insulin-like growth factor receptor-Akt cell survival pathway

G-protein coupled receptor (GPCR) agonists such as neuropeptides activate the insulin-like growth factor-1 receptor (IGF-IR) or the serine-threonine protein kinase Akt, suggesting that neuropeptides-GPCR signaling can cross-communicate with IGF-IR-Akt signaling pathways. Neutral endopeptidase 24.11 (NEP) is a cell-surface peptidase that cleaves and inactivates the neuropeptides endothelin-1 (ET-1) and bombesin, which are implicated in progression to androgen-independent prostate cancer (PC). We investigated the mechanisms of NEP regulation of neuropeptide-mediated cell survival in PC cells, including whether neuropeptide substrates of NEP induce phosphorylations of IGF-IR and Akt in PC cells. Western analyses revealed ET-1 and bombesin treatment induced phosphorylation of IGF-IRbeta and Akt independent of IGF-I in TSU-Pr1, DU145, and PC-3 PC cells, which lack NEP expression, but not in NEP-expressing LNCaP cells. Recombinant NEP and induced NEP expression in TSU-Pr1 cells using a tetracycline-repressive expression system inhibited ET-1-mediated phosphorylation of IGF-IRbeta and Akt, and blocked the protective effects of ET-1 against apoptosis induced by serum starvation. Incubation of TSU-Pr1 cells with specific kinase inhibitors together with ET-1 or bombesin showed that IGF-IR activation is required for neuropeptide-induced Akt phosphorylation, and that neuropeptide-induced Akt activation is predominantly mediated by Src and phosphatidylinositol 3-kinase but not by mitogen-activated protein kinase or protein kinase C. These data show that the neuropeptides ET-1 and bombesin stimulate ligand-independent activation of the IGF-IR, which results in Akt activation, and that this cross-communication between GPCR and IGF-IR signaling is inhibited by NEP.

Effect of growth hormone on intestinal Na+/glucose cotransporter activity

BACKGROUND

Growth hormone (GH) has been used alone or as part of a defined regimen in the treatment of patients with short bowel syndrome; however its mode of action remains unclear. Growth hormone has been shown to increase amino acid, water, and electrolyte absorption from the small intestine. The acute effect of growth hormone on intestinal sugar transport has not been described previously.

METHODS

Mucosal preparations of rat jejunum were mounted in the Ussing chamber. Growth hormone (2 x 10(-6) M or 8 x 10(-6) M) or vehicle was added to the serosal chamber 1, 3, or 5 hours later. Twenty or 40 minutes after growth hormone addition, 30 mmol/L 3-O-methylglucose was added to both chambers, and the change in short-circuit current (deltaIsc) was recorded. In separate experiments, tissues were pretreated with phloridzin, an inhibitor of Na+/glucose cotransport, before the addition of 3-O-methylglucose. In the final set of experiments, kinetic studies were performed.

RESULTS

GH did not induce any alterations in baseline electrical parameters. Only tissues left in the chambers for 5 hours, but not 1 or 3 hours, before GH treatment displayed a greater 3-O-methylglucose-induced deltaIsc than controls (p < .05). The increase in Isc induced by 3-O-methylglucose was 100% phloridzin-inhibitable. Kinetic analysis showed that growth hormone administration is associated with an increase in Na+/glucose cotransporter maximal velocity (Vmax) but no significant change in carrier affinity for substrate (Km).

CONCLUSIONS

Growth hormone increases intestinal sugar transport, but only in tissue that has not been exposed to endogenous GH for over 3 hours.