Discovery of antiandrogen activity of nonsteroidal scaffolds of marketed drugs

Finding good drug leads de novo from large chemical libraries, real or virtual, is not an easy task. High-throughput screening is often plagued by low hit rates and many leads that are toxic or exhibit poor bioavailability. Exploiting the secondary activity of marketed drugs, on the other hand, may help in generating drug leads that can be optimized for the observed side-effect target, while maintaining acceptable bioavailability and toxicity profiles. Here, we describe an efficient computational methodology to discover leads to a protein target from safe marketed drugs. We applied an in silico "drug repurposing" procedure for identification of nonsteroidal antagonists against the human androgen receptor (AR), using multiple predicted models of an antagonist-bound receptor. The library of marketed oral drugs was then docked into the best-performing models, and the 11 selected compounds with the highest docking score were tested in vitro for AR binding and antagonism of dihydrotestosterone-induced AR transactivation. The phenothiazine derivatives acetophenazine, fluphenazine, and periciazine, used clinically as antipsychotic drugs, were identified as weak AR antagonists. This in vitro biological activity correlated well with endocrine side effects observed in individuals taking these medications. Further computational optimization of phenothiazines, combined with in vitro screening, led to the identification of a nonsteroidal antiandrogen with improved AR antagonism and marked reduction in affinity for dopaminergic and serotonergic receptors that are the primary target of phenothiazine antipsychotics.

Prognostic significance of positive lymph nodes in carcinoma of the cervix following radical hysterectomy

5538

Background: Lymph node (LN) metastases portend a poor outcome in women with carcinoma of the uterine cervix, but little data quantitatively evaluate nodal metastasis in relation to prognosis. We queried a large population database to analyze the number of positive LN in relation to survival following radical hysterectomy and lymphadenectomy. Methods: Data were collected from the Surveillance, Epidemiology, and End Results (SEER) Program on women who had primary surgery for the years 1988–2003 (n = 4,559). Analyses using the chi-square test and Cox proportional hazards regression were performed. Exploratory analysis revealed equivalent statistical outcomes in each group for 0 (n = 3,715), 1–2 (n = 552), 3–9 (n = 261), and ≥10 (n = 31) positive LNs, respectively. Results: The median number of LNs removed per patient has significantly declined in recent years (median = 21 for 1988–1998, median = 18 1998–2003, p=.003). The 5-year rates of cause specific (CSS) and overall survival (OS) were 94% and 91%, 76% and 69%, 62% and 58%, and 41% and 35% for 0, 1–2, 3–9 and ≥10 positive LNs, respectively. Favorable stage and grade predicted for survival on multivariate analysis. Adenocarcinoma histology predicted significantly inferior CSS (p=.007) and OS (p=.01) compared to squamous histology in women with positive LNs, but predicted improved OS (p=.004) in women with LN negative disease. An increasing number of LNs removed significantly benefited OS (p=.001). The strongest predictors for both CSS and OS were ≥10 positive LN (HR 1.8 CI 1.2–2.7, p<.0001) a positive LN ratio >25% (HR 1.8 CI 1.5–2.2, p<.0001) and paraaortic LN metastasis (HR 2.1 CI 1.6–2.8, p<.0001). Conclusions: The extent of lympadenectomy has declined since 1988 within the SEER. LN positive disease in carcinoma of the cervix portends a prognosis that is inversely proportional to the number of involved nodes. Adenocarcinoma histology predicted for a more aggressive or benign phenotype depending on LN status. A positive LN ratio >25% demonstrated diminished survival suggesting that the quantitative LN burden is predictive of prognosis. Nodal involvement of the paraaortic region remains a strong indicator of mortality.

No significant financial relationships to disclose.

Population-based study of the incidence, mortality and prognostic factors of small cell carcinoma of the cervix: Analysis of the Surveillance, Epidemiology and End Results database

5546

Background: Small cell carcinoma (SmC) is a rare histology of the cervix uteri that is generally associated with a poor prognosis. This is a population-based study of SmC using the Surveillance, Epidemiology and End Results (SEER). Methods: From 1977 to 2003, 290 women with SmC of the cervix uteri were identified. In addition, 27,527 patients with squamous cell carcinoma (SC) and 5231 with adenocarcinoma (AC) of the cervix were identified for comparison. The annual incidence of each histology was determined and examined for trend. The patient and disease characteristics at diagnosis were examined for each histology, and prognostic factors were evaluated for SmC. Mortality rates of SmC and other histologies were compared via log-rank tests. Results: Mean annual incidence of SmC was 0.03 per 100,000 women compared to 3.5 and 0.62 for SC and AC. A significant change in incidence was identified for SC and AC (p<0.05), but not for SmC (p=0.595). Patients with SmC were more likely to be treated with radiotherapy and to present with more advanced stage, lymph node involvement and distant metastasis than SC and AC (p<0.05). Survival rates for SmC at 2 and 5 years were 46.8% and 35.7%, which were worse compared to SC (HR 0.45; 95% CI: 0.36–0.57) and AC (HR 0.31; 95% CI: 0.25–0.39). The difference in survival is predominantly in patients with early stage, localized disease, and those treated with surgery ( Table ). Multivariate analysis of SmC, race, FIGO stage, age and hysterectomy alone significantly impacted prognosis (p<0.05), while year of diagnosis, lymph node involvement, tumor size, marital status and other treatment modality did not. Conclusions: SmC is an uncommon histologic variant of cervix cancer associated with a worse prognosis compared to SC and AC with a predilection for metastasis at diagnosis. FIGO stage, age and race are prognostic factors for survival.

[Table: see text]

No significant financial relationships to disclose.

Plasma EBV DNA and cell-free GAPDH DNA as prognostic factors of locally advanced nasopharyngeal carcinoma

6053

Background: Plasma cell-free nucleic acids have been investigated to be potential prognostic and predictive markers of treatment response, residual disease, and survival of cancer patients. However, these nucleic acids will be confounded by normal cell death, which might be caused by cancer-related inflammation, infection, or chemotherapy. Nasopharyngeal carcinoma is endemic in Taiwan, highly related to EBV infection. Plasma EBV DNA level has been suggested to be predictive of disease status and outcomes. We try to find out whether plasma EBV and cell-free glyceraldehydes-3-phosphate dehydrogenase DNA before definite treatment of locally advanced NPC predict tumor outcomes better. Methods: 144 stage IV (AJCC version 6) NPC patients received induction chemotherapy followed by concurrent chemoradiotherapy in National Taiwan University Hospital from 1998 to 1999. Pre-treatment blood samples were colleted for real-time quantitative polymerase chain reactions of EBV and GAPDH DNA. The results will be analyzed by SPSS version 13 to see if correlated with tumor extent, locoregional/distant failure, and overall survival. Results: Our patients were mainly composed of T4(97%) and N2(56%) patients. 23 % were in N3 stage. Plasma EBV and cell-free GAPDH DNA levels were not correlated with T stage. Plasma EBV DNA level was significantly correlated with N3 status(Mann-Whitney test p=0.021). After Cox regression model, only age (p=0.024) was a significant predictor of recurrence-free survival; N3 status(p=0.007) and positive plasma EBV DNA (p=0.002) predicted shorter metastasis-free survival. N3 status (p=0.031) and positive plasma EBV DNA (p=0.002) were significantly related to poor survival by log-rank test; whereas T4 lesions (p=0.524) and plasma cell-free GAPDH DNA level (p=0.182) were not. After multivariate Cox regression, positive plasma EBV DNA (hazard ratio 4.936 p=0.006) was the only significant predictor of poor survival. Conclusions: To use circulating DNA as prognostic marker, a specific one, such as EBV DNA, might be better than a non-specific one, like GAPDH DNA. This is important in the development of tumor markers for other solid tumors.

No significant financial relationships to disclose.

Imaging and therapy for Epstein-Barr virus-associated gastric cancer

4644

Background: Epstein-Barr virus (EBV) has been identified in a wide variety of malignancies, including gastric carcinomas. The virus encodes kinases that phosphorylate nucleoside analogs such as 2’-deoxy-2’-fluoro-5-iodo-1-beta-D- arabinofuranosyluracil (FIAU). We hypothesized that it might be possible to use the viral enzyme to specifically concentrate [125I]FIAU or [131I] FIAU in tumor cells harboring virus and thus deliver imaging and therapeutic radiation. Bortezomib is a potent stimulator of viral kinase expression in EBV tumor cell lines. Methods: We imaged lytic induction in vivo and evaluated the effect of [131I] FIAU on human cancer xenografts in SCID mice. These include a tumor line engineered to constitutively express the EBV thymide kinase (EBVTK), and a control engineered with a sham vector (SHAM), as well one EBV-associated human gastric tumor (KT tumor). Mice were treated with buffer, bortezomib (2μg/g), or radiolabeled FIAU or radiolabeled FIAU and bortezomib in combination. For imaging, mice, [125I]-FIAU and SPECT/CT were used. For therapy, 131I-FIAU was used and tumor dimensions were monitored with calipers. Results: SPECT/CT imaging with [125I]-FIAU of tumor-bearing SCID mice showed selective concentration of radiotracer in tumor tissue in EBVTK (3/3) and in EBV-associated KT tumors (3/3) when animals were pretreated with bortezomib. Treatment with buffer had no effect on 3 EBVTK tumors and 3 SHAM tumors all of which increased in volume. Treatment with 1.6 mCi of [131I]-FIAU alone led to tumor response in 3/3 mice with EBVTK tumors and 0/3 mice with SHAM tumors. Treatment with [131I]-FIAU alone had no effect on EBV KT tumor xenografts (0/3) and all tumors increased in volume. Treatment with bortezomib induced modest responses in all KT tumors. However, treatment with bortezomib and [131I]-FIAU led to marked tumor regression (>80%) in EBV-associated KT tumors (3/3). Conclusions: Treatment with bortezomib leads to selective concentration of radiolabeled FIAU in the EBV-associated tumor xenografts. In combination with [131I]-FIAU it leads to tumor regression.

No significant financial relationships to disclose.

Identification of sensitivity markers for BMS-536924, an inhibitor for insulin-like growth factor-1 receptor

3506

Background: Insulin-like growth factor-1 receptor (IGF-1R) signaling is an important regulator of mitogenesis, transformation to the oncogenic phenotype and anti-apoptotic effects in malignant cells. Over-expression of IGF-1R, seen in many tumors, may confer a growth advantage or drug resistance. A potent small-molecule inhibitor (BMS-536924) of IGF-1R tyrosine kinase showed anti-tumor activity in sarcoma, prostate, colon and pancreatic tumor models. One of the integral goals in the development of BMS-536924 as a cancer therapeutic is to identify molecular biomarkers predictive of response to the drug that ultimately will aid in selecting the patients who are most likely to benefit. Methods: The sensitivity (IC50) to BMS-536924 was determined for a panel of 29 pediatric sarcoma and neuroblastoma cell lines. Both microarray and LC/MS based protein profiling were utilized to analyze the baseline gene or protein expression level. Drug treatment studies were performed using two rhabdomyosarcoma cell lines, Rh41 (sensitive to BMS-536924) and Rh36 (resistant to the drug) to identify markers that are modulated by BMS-536924. Results: (1). Sixteen out of the 29 cell lines were highly sensitive to BMS-536924; candidate markers that correlated with the sensitivity to BMS-536924 were identified by gene expression and protein profiling. (2). Histological correlation was also discovered, with specific subtypes of sarcoma having a low IC50 to BMS-536924. (3). Pathway analysis noted that some major candidate markers are common key steps in the EGF-R pathway and the IGF1-R pathway. This observation of cross-talk between the two pathways led to the hypothesis of synergy with combined inhibition of both pathways. Combination studies of BMS-536924 and EGFR inhibitors were performed and synergism was observed. (4). Markers modulated by BMS-536924 in a sensitive cell line were identified. Conclusions: This work has identified candidate markers correlating to BMS-536924 sensitivity in vitro. The possible mechanism of synergistic activity of IGF1-R and EGFR inhibitors will be presented.

No significant financial relationships to disclose.

Effects of site-specific polyethylene glycol modification of recombinant human granulocyte colony-stimulating factor on its biologic activities

BACKGROUND

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is a long-chain cytokine that is administered to stimulate the production of white blood cells (WBCs) to reduce the risk of serious infection in immunocompromized patients. However, to achieve sustained stimulation of WBC production, rhG-CSF must be administered frequently, thus limiting its clinical use.

METHODS

We conjugated rhG-CSF with linear monomethoxy-polyethylene glycol (PEG) maleimide at amino acid residue Cys(17) to test our hypothesis that this could extend the in vivo half-life of rhG-CSF in blood.

RESULTS

The mono-PEG rhG-CSF became more stable to pH, temperature, and enzyme degradation in vitro, and had granulopoietic activity that was superior to the unmodified form in vivo. The granulopoietic activity of PEG-G-CSF was 2.82-fold greater than that of unmodified G-CSF.

CONCLUSIONS

These results indicate that the thiol-specific PEGylation remarkably prolonged the half-life of rhG-CSF and represents a novel strategy to address the more clinically acceptable therapeutic application of hemopoietic growth factor.

Determination of four major saponins in the seeds of Aesculus chinensis Bunge using accelerated solvent extraction followed by high-performance liquid chromatography and electrospray-time of flight mass spectrometry

A new method based on accelerated solvent extraction (ASE) followed by a reliable high-performance liquid chromatography-diode array detector (HPLC-DAD) and positive ion electrospray-time of flight mass spectrometry (ESI-TOF/MS) analysis has been developed for the characterization and quantification of four major saponins in extracts of the seeds of Aesculus chinensis Bunge (semen aesculi). The saponins escin Ia, escin Ib, isoescin Ia and isoescin Ib were extracted from seeds of A. chinesis Bunge via ASE, and the operational parameters of ASE were optimized, such as extraction solvent, extraction temperature, static extraction time and extraction cycles. The optimized procedure employed 70% MeOH as extraction solvent, 120 degrees C of extraction temperature, 7 min of static extraction time, 60% flush volume and the extraction recoveries of the four compounds were nearly to 100% for two cycles. The HPLC conditions are as follows: SinoChrom ODS BP C18 (4.6 mm x 200 mm, 5 microm) column, acetonitrile and 0.10% phosphoric acid solution as mobile phase, flow rate is 1.0 mL min(-1), detection length of UV is 203 nm, injection volume is 10 microL. The results indicated that the developed HPLC method is simple, sensitive and reliable for the determination of four major saponins in seeds of A. chinesis Bunge with a good linearity (r2 > 0.9994), precision (relative standard deviation (R.S.D.) < 1.5%) and the recovery ranges of 95.2-97.3%. The limits of detection (LOD) of the four compounds were in the range of 0.40-0.75 microg mL(-1). This assay can be readily utilized as a quality control method for semen aesculi and other related medicinal plants.

Roles for negative cell regulator 14-3-3sigma in control of MDM2 activities

The 14-3-3sigma, upregulated by p53 in response to DNA damage, can have a positive-feedback impact driving p53 activities and is a human cancer epithelial marker downregulated in various tumors. However, the precise roles of 14-3-3sigma during tumorigenesis are not well characterized. Here, we show that 14-3-3sigma is a critical regulator of murine double minute oncogene (MDM2). 14-3-3sigma interacts with MDM2 at the RING domain. The C-terminal region of 14-3-3sigma binds to MDM2 very efficiently. Importantly, 14-3-3sigma overexpression leads to destabilization of MDM2 through enhancing MDM2 self-ubiquitination and accelerating turnover rate. Conversely, loss of 14-3-3sigma results in a significant increase in MDM2 protein. Moreover, live-cell images indicated that 14-3-3sigma can affect the location of MDM2 from the nucleus to the cytoplasm, and that MDM2-mediated cytoplasmic localization of p53 can be reversed by the presence of 14-3-3sigma. Significantly, we further showed that 14-3-3sigma causes MDM2 downregulation, thereby stabilizing p53 and inhibiting tumor growth in animal tumors. Also, 14-3-3sigma blocks MDM2-mediated retinoblastoma degradation and p53 NEDDylation. Our results provide evidence that 14-3-3sigma is a pivotal MDM2 regulator involved in blocking a variety of activities of MDM2.

Surface motility of Xylella fastidiosa visualized by oblique illumination

Stereomicroscopic observations using oblique illuminations revealed the presence of two types of movement trails by Xylella fastidiosa strains (A- and G-genotypes) isolated from almond-leaf scorch samples on the surface of PW and PD3 culture media. The A-genotype strains showed curved motility trails, and the G-genotype strains showed straight motility trails. Haloes were found around some G-genotype colonies due to the excretion of unknown factors and (or) compounds, which might be related to bacterial surface motility.

The behaviour of Fusobacterium nucleatum chemostat-grown in glucose- and amino acid-based chemically defined media

Fusobacterium nucleatum is a Gram-negative anaerobe, found in a number of different areas of human and animal bodies as part of the resident microbiota. However, it also appears to be involved in polymicrobial infections in such sites. It occurs in the oral cavity where it is a prominent member of various bacterial consortia associated with periodontal diseases. Like most fusobacteria, it derives energy via the fermentation of amino acids which it can obtain through the dissimilation of small peptides. However, the role of simple carbohydrates, such as glucose, in its growth and metabolism are not well understood. Accordingly, the aim of the present study was to study the behaviour ofF. nucleatum grown anaerobically in continuous culture in two different chemically-defined media (CDM); one containing only amino acids as the energy source, the other containing glucose as the predominant energy provider. At various dilution rates the culture were assayed for dry weight, intracellular polyglucose (IP) content, residual amino acids and glucose and acidic metabolic end-products. In the carbohydrate-free CDM the acidic end-products were a constant acetate : butyrate : formate of 1.5 : 1 : 0.4. The values of Y(max)amino acids, maximum yield of bacteria per mol of amino acids consumed, for two strains were estimated to be 15.2 and 18.6 g dry wt/mol, respectively. Them(amino acids), maintenance energy requirement for growth on amino acids, for the two strains was 0.81 and 0.94 mmol/g dry wt/h, respectively. Growth of one strain in the glucose-based CDM gave an estimated Y(max)glucose of 67.2 and an m(glucose) of 0.38; the acidic end-products were a fairly constant acetate : butyrate : formate : lactate of 0.7 : 1 : 0.3 : 2.5. Only at low growth rates, and then only in small amount, was IP produced in this medium. Overall, it was concluded that the occurrence of F. nucleatum in widely-differing oral niches may be explained, at least in part, by its metabolic versatility.

An evaluation of computer-aided disproportionality analysis for post-marketing signal detection

To understand the value of computer-aided disproportionality analysis (DA) in relation to current pharmacovigilance signal detection methods, four products were retrospectively evaluated by applying an empirical Bayes method to Merck's post-marketing safety database. Findings were compared with the prior detection of labeled post-marketing adverse events. Disproportionality ratios (empirical Bayes geometric mean lower 95% bounds for the posterior distribution (EBGM05)) were generated for product-event pairs. Overall (1993-2004 data, EBGM05> or =2, individual terms) results of signal detection using DA compared to standard methods were sensitivity, 31.1%; specificity, 95.3%; and positive predictive value, 19.9%. Using groupings of synonymous labeled terms, sensitivity improved (40.9%). More of the adverse events detected by both methods were detected earlier using DA and grouped (versus individual) terms. With 1939-2004 data, diagnostic properties were similar to those from 1993 to 2004. DA methods using Merck's safety database demonstrate sufficient sensitivity and specificity to be considered for use as an adjunct to conventional signal detection methods.

Polymorphisms of ACE2 gene are associated with essential hypertension and antihypertensive effects of Captopril in women

ACE2 appears to counterbalance the vasopressor effect of angiotensin I converting enzyme (ACE) in the reninangiotensin system. We hypothesized that ACE2 polymorphisms could confer a high risk of hypertension and have an impact on the antihypertensive response to ACE inhibitors. The hypothesis was tested in two casecontrol studies and a clinical trial of 3,408 untreated hypertensive patients randomized to Atenolol, Hydrochlorothiazide, Captopril, or Nifedipine treatments for 4 weeks. ACE2 rs2106809 T allele was found to confer a 1.6-fold risk for hypertension in women (95% confidence interval (CI), 1.132.06), whereas when combined with the effect of the ACE DD genotype, the risk was 2.34-fold (95% CI, 1.754.85) in two independent samples. The adjusted diastolic blood pressure response to Captopril was 3.3 mm Hg lower in ACE2 T allele carriers than in CC genotype carriers (P=0.019) in women. We conclude that the ACE2 T allele confers a high risk for hypertension and reduced antihypertensive response to ACE inhibitors.