Dinucleotide repeats negatively modulate the promoter activity of Cyr61 and is unstable in hepatocellular carcinoma patients

Cyr61 is a secreted, cysteine-rich, heparin-binding protein that mediates diverse functions including extracellular matrix formation, differentiation, cell proliferation, adhesion, migration, survival, as well as angiogenesis and tumorigenesis. In this study, we found that Cyr61 gene expression is significantly downregulated in the tumors of hepatocellular carcinoma (HCC) patients. To elucidate its mechanism of gene regulation, we examined the promoter of Cyr61 which contains two long stretches of repeats, each comprising d(CA) dinucleotide repeats downstream of HNF3beta- and ATF-binding sites. We hypothesized that the d(CA) repeats may play an important role in regulating Cyr61 promoter activity and performed promoter reporter assays to examine this. We found that a greater number of d(CA) repeats resulted in significantly lower promoter activity of the Cyr61 gene in the KB3-1 and HepG2 cell lines, but not in the MCF-7 cell line. In addition, the d(CA) repeats, but not other random sequences, were found to be important for Cyr61 promoter activity. We further demonstrate that the ATF- and HNF3beta-binding sites upstream the d(CA) repeats positively and negatively modulate Cyr61 promoter activity, respectively. An examination of the d(CA) dinucleotide patterns in the Cyr61 promoter in HCC patients revealed that approximately 32% of these patients exhibited either loss of heterozygosity or somatic mosaicism in either the tumors, adjacent normal liver tissues or both.     

New science-based endpoints to accelerate oncology drug development

Although several new oncology drugs have reached the market, more than 80% of drugs for all indications entering clinical development do not get marketing approval, with many failing late in development often in Phase III trials, because of unexpected safety issues or difficulty determining efficacy, including confounded outcomes. These factors contribute to the high costs of oncology drug development and clearly show the need for faster, more cost-effective strategies for evaluating oncology drugs and better definition of patients who will benefit from treatment. Remarkable advances in the understanding of neoplastic progression at the cellular and molecular levels have spurred the discovery of molecularly targeted drugs. This progress along with advances in imaging and bioassay technologies are the basis for describing and evaluating new biomarker endpoints as well as for defining other biomarkers for identifying patient populations, potential toxicity, and providing evidence of drug effect and efficacy. Definitions and classifications of these biomarkers for use in oncology drug development are presented in this paper. Science-based and practical criteria for validating biomarkers have been developed including considerations of mechanistic plausibility, available methods and technology, and clinical feasibility. New promising tools for measuring biomarkers have also been developed and are based on genomics and proteomics, direct visualisation by microscopy (e.g., confocal microscopy and computer-assisted image analysis of cellular features), nanotechnologies, and direct and remote imaging (e.g., fluorescence endoscopy and anatomical, functional and molecular imaging techniques). The identification and evaluation of potential surrogate endpoints and other biomarkers require access to and analysis of large amounts of data, new technologies and extensive research resources. Further, there is a requirement for a convergence of research, regulatory and drug developer thinking - an effort that will not be accomplished by individual scientists or research institutions. Research collaborations are needed to foster development of these new endpoints and other biomarkers and, in the United States (US), include ongoing efforts among the Food and Drug Administration (FDA), National Cancer Institute (NCI), academia, and industry.     

Involvement of both intrinsic and extrinsic pathways in IFN-gamma-induced apoptosis that are enhanced with cisplatin

IFN-gamma has direct anti-proliferative effects on ovarian cancer cell lines and tumour cells isolated from ovarian cancer ascites. The aim of this study was to further elucidate the mechanisms involved. An IFN-gamma-mediated cell cycle blockade was detectable in synchronised cell populations. Apoptosis, which was caspase dependent, was also induced. When caspase activity was blocked, the anti-proliferative effect of IFN-gamma was only partially reduced indicating independent roles for both growth inhibition and apoptosis in its actions. We have demonstrated involvement of the intrinsic apoptotic pathway; IFN-gamma treatment resulted in mitochondrial membrane depolarisation, cytochrome c release into the cytosol and activation of caspase 9. Cytochrome c release was blocked by the presence of a general caspase inhibitor, suggesting a role for caspases upstream of the mitochondria. One candidate is caspase 8, which was also activated in cells treated with IFN-gamma. Levels of Bid, a pro-apoptotic molecule that can mediate mitochondrial membrane permeabilisation when cleaved by caspase 8, were also decreased and indicated a potential link between these two pathways in IFN-gamma-induced apoptosis. Furthermore, together with cisplatin, IFN-gamma exerted a more powerful anti-proliferative effect.     

Using single-agent therapy in adult patients with advanced soft tissue sarcoma can still be considered standard care

The group of soft tissue sarcomas in adult patients is a heterogeneous group with more than 40 different subtypes. While local treatment remains the mainstay for localized disease, systemic chemotherapy can importantly contribute in the treatment of advanced soft tissue sarcoma. For patients with metastatic disease, chemotherapy is a palliative treatment in the vast majority of the cases. In this setting, toxicity should not outweigh the potential benefits resulting from chemotherapy. In patients with locally advanced disease too extensive for local treatment, systemic chemotherapy can contribute to cure, provided that tumor shrinkage renders subsequent optimal local treatment possible. In these cases, chemotherapeutic regimens yielding the highest response rates achievable should be used. In the last decades, several randomized studies have aimed to determine whether combination regimens yield benefit over single-agent treatment in terms of response rate and overall survival. This review addresses the current available data on chemotherapy for adult patients with soft tissue sarcoma, excluding gastrointestinal stromal tumor, the Ewing-like sarcomas, and other small blue round cell tumors. In addition, it is increasingly recognized that future research in soft tissue sarcoma should focus on the identification of tumor factors that can serve as targets for treatment and that the diverse tumor subtypes should be analyzed separately for their sensitivity to systemic treatment. This review also focuses on these and other strategies that will hopefully lead to better out comes in this disease entity in the near future.     

Compression of controlled-release pellets produced by a hot-melt extrusion and spheronization process

The purpose of this study was to investigate the physicomechanical and dissolution properties of tablets containing controlled-release pellets prepared by a hot-melt extrusion and spheronization process. A powder blend of anhydrous theophylline, Eudragit Preparation 4135 F, and functional excipients was melt-extruded, pelletized, and then spheronized. The pellets were compressed into tablets using forces of 5, 10, 15, and 20 kN. Tablet diluents included microcrystalline cellulose, a mixture of spray-dried lactose and microcrystalline cellulose, modified food starch, and soy polysaccharides. The effective porosity of the compressed pellets was measured using mercury porosimetry and helium pycnometry, while the surface area was determined using Brunauer, Emmett, and Teller (BET) analysis. The disintegration time, hardness, and friability of compacts were determined. Drug release studies were performed according to USP 27 Apparatus 3 guidelines in 250 mL of medium (pH 1.0, 3.0, 5.0, 6.8, and 7.4) 37 degrees C and 20 dpm. Samples were analyzed by high pressure-liquid chromatography (HPLC). Effective porosity and surface area determinations of the melt-extruded pellets were not influenced by compression. The percent of theophylline released from rapidly disintegrating tablets was not affected by compression force or excipient selection, but tablets with prolonged disintegration times exhibited delayed drug release in acidic media. However, dissolution profiles of uncompressed pellets and all compacts were identical after transition from 0.1 N HCl to media increasing in pH from 3.0 to 7.4. Furthermore, pellet to filler excipient ratio and filler excipient selection did not influence the rate of drug release from compacts.     

Effectiveness of amoxicillin, azithromycin, cefprozil and clarithromycin in the treatment of acute otitis media in children: a population-based study

Population-based studies may give results different from randomized clinical trials assessing the efficacy of antibiotics.OBJECTIVE: To determine the effectiveness of amoxicillin, azithromycin, cefprozil and clarithromycin in the treatment of acute otitis media (AOM) in children. METHODS: Using Quebec Health Insurance databases (RAMQ), we selected a cohort of children aged < or = 6 years, with a first episode of AOM between 1999 and 2002. The index AOM was defined as a medical service claim with a diagnosis of AOM and an antibiotic dispensation in the following 72 hours. Failures were defined as a new antibiotic dispensation, a hospitalization or outpatient visit for complications related to AOM in the 30 days after the index AOM. Data were analyzed using logistic regression. RESULTS: Overall, 12,693 failures occurred among 60,513 first episodes of AOM. Azithromycin was the only antibiotic that was associated with a decreased risk of failure overall, when compared to amoxicillin (OR 0.88, 95% CI: 0.82, 0.94). However in the first 3 days of treatment (n = 680), azithromycin was more associated with treatment failure (OR 1.6, 95% CI: 1.3, 2.0). Compared to amoxicillin, post-therapy failures (n = 9387) were more likely to occur with cefprozil (OR 1.2, 95%CI: 1.2, 1.3) but were less with azithromycin (OR 0.8 95% CI: 0.8, 0.9). CONCLUSIONS: Azithromycin had the lowest risk of failure 30 days after the onset of treatment but an increased risk of failure during the first few days of treatment. Amoxicillin remains an effective first-line drug for treating first AOM episodes.