HSA-ZW800-PEG for Enhanced Optophysical Stability and Tumor Targeting

Small molecule fluorophores often face challenges such as short blood half-life, limited physicochemical and optical stability, and poor pharmacokinetics. To overcome these limitations, we conjugated the zwitterionic near-infrared fluorophore ZW800-PEG to human serum albumin (HSA), creating HSA-ZW800-PEG. This conjugation notably improves chemical, physical, and optical stability under physiological conditions, addressing issues commonly encountered with small molecules in biological applications. Additionally, the high molecular weight and extinction coefficient of HSA-ZW800-PEG enhances biodistribution and tumor targeting through the enhanced permeability and retention effect. The unique distribution and elimination dynamics, along with the significantly extended blood half-life of HSA-ZW800-PEG, contribute to improved tumor targetability in both subcutaneous and orthotopic xenograft tumor-bearing animal models. This modification not only influences the pharmacokinetic profile, affecting retention time and clearance patterns, but also enhances bioavailability for targeting tissues. Our study guides further development and optimization of targeted imaging agents and drug-delivery systems.

Relationship Between Body Mass Index and Dental Development in a Contemporary Pediatric Population in the United States

Purpose: To determine if there is a positive correlation between increased body mass index (BMI) and dental development in children.<br/>Methods: The records of 500 six- to 13-year-old children were reviewed, and 250 were included in the study. BMI was calculated for each patient. Panoramic radiographs were evaluated, and dental age was estimated using Cameriere's formula. Delta values (dental age, chronological age) were analyzed using the Kruskal-Wallis test. All tests of hypotheses were two-sided at an alpha level of 0.05.<br/>Results: A statistically significant difference in delta was observed among different BMI categories (P <0.001). Larger deltas were observed for obese patients compared to normal weight patients (P = 0.027) and underweight patients (P = 0.012). Prepubertal patients were observed to have larger deltas than pubertal patients (P < 0.001). Differences between sexes were not significant (P = 0.930).<br/>Conclusion: Obese children were more advanced dentally than normal or under-weight children. Older children were more dentally advanced than their chronological age when compared to younger children. As children grew older, the difference between dental age and chronological age decreased.

Abstract C77: In vivo anticancer activity of an aurora kinase inhibitor, VX-680, in gastric cancer

Background: Aurora kinases (AK) constitute one family of seine/threonine kinases, whose activity is essential for mitotic progression. Expression of aurora kinase is greatest in G2-M phase, and their function includes spindle formation, centrosome maturation, chromosomal segregation, and cytokinesis. Over-expression of AK is related to aneuploidy and carcinogenesis. Herein, we investigated the in vitro and in vivo anticancer acvitivity of a novel AK inhibitor, VX-680 in gastric cancer.

Methods: AK protein expression and kinase activity were screened in gastric cancer cell lines using immunoblot and in vitro kinase assay, respectively. The anti-proliferative activity of VX-680 was measured using MTT assay. The changes of cell cycle by the treatment of VX-680 were analyzed by flow cytometry. YCC-16 cell line selected for tumor xenograft models. In vivo activity validation using mouse xenograft models and extract protein or tissue slide from each tumors.

Results: AK protein expression and its kinase activity were variable among cell lines. VX-680 showed anti-proliferative effect in vitro on a wide range of gastric cancer cell lines, and calculating the IC50 value, it was distributed from 0.04uM to 19.87uM. It was correlated with kinase activity, not with protein expression of AK. VX-680 induced the reduction of phosphor-histone H3 and the cell cycle defects that accumulated &gt;4N DNA. In vivo experiment, confirmed that AKI had an effect on tumor inhibition. Solid tumor formed with YCC-16 cell lines and VX-680 was injected twice a day for 5 days with a dose of 50mg/kg. Estimating the tumor volume for 21 days after VX-680 injection, the difference in tumor volume between the control and the treated mice were statistically significant. Kinase activity and phospho-histone H3 in VX-680 treated tumor was reduced in drug treatment samples compared to the control samples.

Conclusion: We demonstrated that VX-680 has anti-cancer activity in gastric cancer. Kinase activity of AK might be a predictor for sensitivity of VX-680.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C77.

Turning the [Ru(bpy)2dppz]2+ light-switch on and off with temperature

We report temperature-dependent excited-state lifetime measurements on [Ru(bpy)(2)dppz](2+) in both protic and aprotic solvents. These experiments yield a unifying picture of the excited-state photophysics that accounts for observations in both types of solvent. Our measurements support the notion of bpy-like and phz-like states associated with the dppz ligand and show that the ligand orbital associated with the bright state is similar in size to the corresponding orbital in the (3)MLCT state of [Ru(bpy)(3)](2+). In contrast to the current thinking, the experiments presented here indicate that the light-switch effect is not driven by a state reversal. Rather, they suggest that the dark state is always lowest in energy, even in aprotic solvents, and that the light-switch behavior is the result of a competition between energetic factors that favor the dark state and entropic factors that favor the bright (bpy) state.

Mutation analysis of Korean patients with citrullinemia

Citrullinemia is an autosomal recessive disease due to the mutations in the argininosuccinate synthetase (ASS) gene. Mutation analysis was performed on three Korean patients with citrullinemia. All of the three patients had the splicing mutation previously reported as IVS6-2A>G mutation. Two had Gly324Ser mutation and the other patient had a 67-bp insertion mutation in exon 15. The IVS6-2A>G mutation was reported to be found frequently in Japanese patients with citrullinemia, but Caucasian patients showed the extreme mutational heterogeneity. Although a limited number of Korean patients were studied, the IVS6-2A>G mutation appears to be one of the most frequent mutant alleles in Korean patients with citrullinemia. The Gly324Ser mutation identified in two patients also suggests the possible high frequency of this mutation in Korean patients as well.