Pharmacodynamic Analysis of Target Inhibition and Endothelial Cell Death in Tumors Treated with the Vascular Endothelial Growth Factor Receptor Antagonists SU5416 or SU6668

Inhibitory effect of Gypsophila oldhamiana gypsogenin on NCI-N87 gastric cancer cell line

Gastric cancer is one of the major cancers threatening people’s lives worldwide. Recent studies showed that Gypsophila oldhamiana gypsogenin (GOG) exhibits inhibition effects and cytotoxic activities against different cell lines. The aim of this study was to explore the inhibitory effect and dose response of GOG on gastric cancer cell line NCI-N87 and to provide the theoretical basis for clinical anti-tumor therapy. The experiments showed that GOG could inhibit the proliferation and promote the apoptosis of human gastric cancer cell line NCI-N87. GOG could dose dependently reduce the expression of vascular endothelial growth factor (VEGF) and matrix metalloprotein (MMP)-9 proteins, while increase the expression of caspase-3 and Bax proteins. Compared with model group, tumor volume (TV), relative tumor volume (RTV), and relative tumor increment rate (T/C) in the mid-dose and high-dose GOG groups were significantly reduced, and the inhibition rate (IR) in the two groups was significantly increased. The results indicated that the anti-tumor effect of GOG on gastric cancer cells may be related with the downregulation of caspase-3 and Bax and the upregulation of MMP-9 and VEGF.

Quantitation of spatial and temporal variability of biomarkers for Barrett's Esophagus

Chemoprevention and risk-stratification studies in Barrett's esophagus (BE) rely on biomarkers but the variability in their temporal and spatial expression is unknown. If such variability exists, it will impact sampling techniques and sample size calculations. Specimens from three levels of biopsies over two serial endoscopies in nondysplastic BE patients were analyzed for aneuploidy, proliferation markers (Ki67, Mcm2), and cell cycle markers (cyclin A and cyclin D1). A modification of the image cytometry technique, where cytokeratin staining automatically distinguished epithelial and stromal cells, measured aneuploidy on whole tissue sections. Other biomarkers were studied by immunohistochemistry. Coefficient of variability (SD/mean) was calculated; a value <10% indicated low variability. A total of 120 specimens (20 subjects each with three biopsy levels at two time points) from nondysplastic BE patients (71 ± 8.8 years, all Caucasian, 90% males, C5.1M7.5 ± 3.4 cm) were analyzed. The mean interval between endoscopies was 32.8 ± 8.4 months. Aneuploidy had a spatial variability of 6.8% at visit 1 (mean diploid index: 1.1 ± 0.09) and 7.9% at visit 2 (mean diploid index: 1.1 ± 0.06) and a temporal variability of 7.0-8.1% for the three levels. For other biomarkers, the spatial variability ranged from ∼5 to 30% at visit 1 and 11-92% at visit 2 and the temporal variability ranged from 0 to 77%. To conclude, of all the biomarkers, only aneuploidy had both spatial and temporal variability of <10%. Spatial and temporal variability were biomarker dependent and could be as high as 90% even without progression. These data will be useful to design chemoprevention and risk-stratification studies in BE.

Vegfrecine, an inhibitor of VEGF receptor tyrosine kinases isolated from the culture broth of Streptomyces sp

A new inhibitor of VEGF receptor tyrosine kinases, vegfrecine (1), was isolated from the culture broth of Streptomyces sp. MK931-CF8. The molecular structure of 1 was determined by NMR and MS analysis combined with synthesis. Compound 1 showed potent inhibitory activity against vascular endothelial growth factor receptor (VEGFR) tyrosine kinases in in vitro enzyme assays, but platelet-derived growth factor receptors (PDGFRs), fibroblast growth factor receptor (FGFR), and epidermal growth factor receptor (EGFR) responded only weakly. Compound 1 is a promising new selective VEGFR inhibitor for investigating new treatments of cancer and inflammatory diseases.

Publication and reporting conduct for pharmacodynamic analyses of tumor tissue in early-phase oncology trials

PURPOSE

In principle, nondiagnostic biopsies for pharmacodynamic (PD) studies are carried out to inform decision-making in drug development. Because such procedures have no therapeutic value, their ethical justification requires that results be published. We aimed to assess the frequency of nonpublication of PD data in early phase cancer trials and to identify factors that prevent full publication of data.

METHODS

We identified a sample of early-phase cancer trials containing invasive nondiagnostic tissue procurement for PD analysis from American Society of Clinical Oncology and American Association for Cancer Research meeting abstracts published between 1995 and 2005. These trials were followed to publication to determine frequency of nonpublication of PD data. Corresponding authors on early-phase cancer trials using invasive nondiagnostic research procedures were also surveyed to identify factors preventing full publication of PD data.

RESULTS

In a sample of 90 trials, 22.2% (20 trials) resulted in no trial publication. Of published trials expected to contain PD reports, 16 (17.8%) did not include any PD data, and 21 (23.3%) reported incomplete PD data. We surveyed 92 authors; nonpublication was regarded as a frequent occurrence, and the most commonly cited barrier to full publication of PD data was strategic considerations in publication (58.8% of responding authors).

CONCLUSIONS

Our results suggest ways that investigators, study planners, and reviewers can improve the burden/knowledge value balance in PD studies.