The addition of a pregnenolone pendant group enhances the anticancer properties of titanocene dichloride in a mcf-7 xenograft model

BACKGROUND/AIM

Titanocene dichloride held great promise as a chemotherapeutic compound in pre-clinical studies. However, subsequent clinical trials revealed hepatoxicity and nephrotoxicity, which limited its use in clinical applications. Therefore, we used steroid pendant groups to improve the targeting of titanocene in MCF-7 breast cancer cells, and demonstrated a 10-fold lower effective dose compared to titanocene in in vitro assays. The aim of the present study was to test the efficacy of a titanocene functionalized with pregnenolone (Ti-Preg) in an in vivo breast cancer model.

MATERIALS AND METHODS

Xenografts from the MCF7 breast cancer cell line were implanted into athymic nu/nu mice to evaluate the potential of Ti-Preg as an anti-breast cancer agent.

RESULTS

Ti-Preg demonstrated significant inhibition of MCF-7 tumor growth when compared to vehicle and to titanocene controls.

CONCLUSION

Our findings demonstrate the potential of steroid pendent groups for targeting chemotherapeutics to steroid hormone-dependent cancer.

Circulating levels of glucocorticoid hormones in WHHL and NZW rabbits: circadian cycle and response to repeated social encounter

Social environment influences the progression of atherosclerosis in an important experimental model of disease, the Watanabe Heritable Hyperlipidemic rabbit (WHHL). Although the hypothalamic-pituitary-adrenocortical (HPA) system is likely to play an important role in the behavioral modulation of disease, relatively little is known about the glucocorticoid responses in these animals, or in other strains of rabbits. The purpose of the present study was to: (1) evaluate the rabbit glucocorticoid circadian rhythm, (2) compare plasma cortisol and corticosterone responses to social stress, and (3) examine strain differences (i.e., WHHL vs. New Zealand White (NZW)) in rabbit glucocorticoid responses to assess whether WHHLs have an aberrant HPA system. It was found that male rabbits secrete both corticosterone and cortisol in a circadian rhythm that peaks in the afternoon and reaches a nadir at 0600 h, i.e., approximately 12 h out-of-phase with the human glucocorticoid rhythm. Both glucocorticoids responded similarly to social stress induced by repeated daily 4 h pairings with another male rabbit; after 10 days of pairings, glucorticoid values were significantly correlated with the amount of defensive agonistic behavior exhibited. Finally, there were no significant strain differences in glucocorticoid circadian rhythms, baselines, or responses to social stress. These data suggest that glucocorticoid responses (i.e., circadian rhythms, responses to social stress) in the WHHL are similar to glucocorticoid responses in standard laboratory white rabbits.

The pulsatile portal vein in cases of congestive heart failure: correlation of duplex Doppler findings with right atrial pressures

To better understand portal vein pulsatility in congestive heart failure, the authors compared portal vein spectral patterns to right atrial pressures measured with a Swan-Ganz catheter in 17 adult patients suspected of having congestive heart failure. Portal vein pulsatility was also evaluated in 17 healthy adults. A pulsatility score (scale, 1-5) based on a ratio of minimum to peak portal vein velocity was assigned. A score of 1 indicated continuous, monophasic flow, while a score of 5 indicated that flow reversal was observed with each cardiac cycle. All 17 healthy volunteers had portal vein pulsatility scores of 2 or less. Among the 17 patients suspected of having congestive heart failure, seven had normal right atrial pressure (less than 10 mm Hg) and pulsatility scores of 2 or less. Among the 10 patients with a right atrial pressure of 10 mm Hg or greater, six had pulsatility scores of 3 or greater (sensitivity, 60%; specificity, 100%). Greater than 50% of the variation in portal vein score is explained by changes in right atrial pressure. Review of echocardiograms in 13 of 17 patients showed no significant correlation between the degree of tricuspid regurgitation and portal vein score. Portal vein pulsatility is a sign of elevated systemic venous pressure.