Ultrastructural study of the cardiotoxicity and light-microscopic findings of the skin after treatment of golden hamsters with seven different anthracyclines

DNA-binding studies of valrubicin as a chemotherapy drug using spectroscopy and electrochemical techniques

In this study, the molecular interactions between valrubicin, an anticancer drug, and fish sperm DNA have been studied in phosphate buffer solution (pH 7.4) using UV–Vis spectrophotometry and cyclic voltammetry techniques. Valrubicin intercalated into double stranded DNA under a weak displacement reaction with methylene blue (MB) molecule in a competitive reaction. The binding constant (k_b) of valrubicin-DNA was determined as 1.75×10³ L/mol by spectrophotometric titration. The value of non-electrostatic binding constant (kt0) was almost constant at different ionic strengths while the ratio of kt0/k_b increased from 4.51% to 23.77%. These results indicate that valrubicin binds to ds-DNA via electrostatic and intercalation modes. Thermodynamic parameters including ΔH⁰, ΔS⁰ and ΔG⁰ for valrubicin-DNA interaction were determined as −25.21×10³ kJ/mol, 1.55×10² kJ/mol K and −22.03 kJ/mol, respectively. Cyclic voltammetry study shows a pair of redox peaks for valrubicin at 0.45 V and 0.36 V (vs. Ag/AgCl). The peak currents decreased and peak positions shifted to positive direction in the presence of DNA, showing intercalation mechanism due to the variation in formal potential.

Fabrication of an electrochemical sensor for determination of doxorubicin in human plasma and its interaction with DNA

In this work, an electrochemical sensor was fabricated for determination of an anthracycline, doxorubicin (DOX) as a chemotherapy drug in plasma based on multi-walled carbon nanotubes modified platinum electrode (Pt/MWCNTs). DOX was effectively accumulated on the surface of modified electrode and generated a pair of redox peaks at around 0.522 and 0.647 V (vs. Ag/AgCl) in Britton Robinson (B-R) buffer (pH 4.0, 0.1 M). The electrochemical parameters including pH, type of buffer, accumulation time, amount of modifier and scan rate were optimized. Under the optimized conditions, there was a linear correlation between cathodic peak current and concentration of DOX in the range of 0.05-4.0 µg/mL with the detection limit of 0.002 µg/mL. The number of electron transfers (n) and electron transfer-coefficient (α) were estimated as 2.0 and 0.25, respectively. The constructed sensor displayed excellent precision, sensitivity, repeatability and selectivity in the determination of doxorubicin in plasma. Moreover, cyclic voltammetry studies of DOX in the presence of DNA showed an intercalation mechanism with binding constant (K_b) of 1.12×10⁵ L/mol.

Valrubicin in a topical formulation treats psoriasis in a xenograft transplantation model

Valrubicin is a cytostatic drug currently approved by the American Federal Drug Administration as a trademarked Valstar sterile solution for the treatment of bladder cancer. Valrubicin has shown an excellent therapeutic potential with minimal toxicity. This study investigated the effect in vivo of treating psoriasis with a daily topical application of valrubicin cream in a psoriasis xenograft transplantation model. Psoriasis is characterized by an accelerated keratinocyte proliferation, resulting in increased epidermal thickness. We thus studied the cytostatic potential of valrubicin on epidermal keratinocytes. In vivo, valrubicin treatment resulted in a normalization of epidermal morphology and a reduction in epidermal thickness after 12 days. In addition, the dermal vessel pattern was reduced and the stratum granulosum was regained. Staining for a regenerative proliferation marker showed a decrease in keratinocyte proliferation, and scattered epidermal cells showed apoptosis. In vitro, valrubicin was shown to localize solely to the cell cytoplasm in cultured keratinocytes and to reduce keratinocyte proliferation as well as increase apoptosis by activation of caspases 3, 7, and 9. Our results indicated that valrubicin successfully treats psoriasis in a xenograft transplantation model, suggesting that topical valrubicin may become an upcoming treatment for psoriasis.