Synergistic antitumor activity of troxacitabine and camptothecin in selected human cancer cell lines

Mitochondria and nucleus delivery of active form of 10-hydroxycamptothecin with dual shell to precisely treat colorectal cancer

AIM

The objective of this study was to deliver a ring-closed form of 10-hydroxycamptothecin (HCPT) to the mitochondria and nucleus to treat colorectal cancer.

MATERIALS & METHODS

HCPT-loaded nanoparticle HCPT@PLGA-PEG_2k-triphenylphosphonium/PLGA-hyd-PEG_4k-folic acid (PT/PHF) and HCPT@PT/PLGA-SS-PEG_4k-folic acid (PSF) were prepared by using emulsion-solvent evaporation method.

RESULTS

In vitro experimental results indicated HCPT@PT/PHF and HCPT@PT/PSF maintained a large amount of HCPT in active form, and delivered more HCPT to the nucleus and mitochondria of the tumor cell, which resulted in the enhancement of cytotoxicity of HCPT. In vivo experimental results indicated that HCPT@PT/PHF and HCPT@PT/PSF delivered more ring-closed form of HCPT to tumor tissue, which led to strong antitumor activity.

CONCLUSION

HCPT@PT/PHF and HCPT@PT/PSF could enhance therapeutic efficacy of HCPT to colorectal cancer.

Fabrication and optimization of camptothecin loaded Eudragit S 100 nanoparticles by Taguchi L4 orthogonal array design

Introduction:

The objective of this investigation was to design and optimize the experimental conditions for the fabrication of camptothecin (CPT) loaded Eudragit S 100. Nanoparticles, and to understand the effect of various process parameters on the average particles size, particle size uniformity and surface area of the prepared polymeric nanoparticles using Taguchi design.

Materials and Methods:

CPT loaded Eudragit S 100 nanoparticles were prepared by nanoprecipitation method and characterized by particles size analyzer. Taguchi orthogonal array design was implemented to study the influence of seven independent variables on three dependent variables. Eight experimental trials involving seven independent variables at higher and lower levels were generated by design expert.

Results:

Factorial design result has shown that (a) except, β-cyclodextrin concentration all other parameters do not significantly influenced the average particle size (R1); (b) except, sonication duration and aqueous phase volume, all other process parameters significantly influence the particle size uniformity; (c) all the process parameters does not significantly influence the surface area.

Conclusion:

The R1, particle size uniformity and surface area of the prepared drug-loaded polymeric nanoparticles were found to be 120 nm, 0.237 and 55.7 m² /g and the results were good correlated with the data generated by the Taguchi design method.

Hydroxycamptothecin-loaded nanoparticles enhance target drug delivery and anticancer effect

Background

Hydroxycamptothecin (HCPT) has been shown to have activity against a broad spectrum of cancers. In order to enhance its tissue-specific delivery and anticancer activity, we prepared HCPT-loaded nanoparticles made from poly(ethylene glycol)-poly(γ-benzyl-L-glutamate) (PEG-PBLG), and then studied their release characteristics, pharmacokinetic characteristics, and anticancer effects. PEG-PBLG nanoparticles incorporating HCPT were prepared by a dialysis method. Scanning electron microscopy (SEM) was used to observe the shape and diameter of the nanoparticles. The HCPT release characteristics in vitro were evaluated by ultraviolet spectrophotometry. A high-performance liquid chromatography (HPLC) detection method for determining HCPT in rabbit plasma was established. The pharmacokinetic parameters of HCPT/PEG-PBLG nanoparticles were compared with those of HCPT.

Results

The HCPT-loaded nanoparticles had a core-shell spherical structure, with a core diameter of 200 nm and a shell thickness of 30 nm. Drug-loading capacity and drug encapsulation were 7.5 and 56.8%, respectively. The HCPT release profile was biphasic, with an initial abrupt release, followed by sustained release. The terminal elimination half-lives (t 1/2 β) of HCPT and HCPT-loaded nanoparticles were 4.5 and 10.1 h, respectively. Peak concentrations (Cmax) of HCPT and HCPT-loaded nanoparticles were 2627.8 and 1513.5 μg/L, respectively. The apparent volumes of distribution of the HCPT and HCPT-loaded nanoparticles were 7.3 and 20.0 L, respectively. Compared with a blank control group, Lovo cell xenografts or Tca8113 cell xenografts in HCPT or HCPT-loaded nanoparticle treated groups grew more slowly and the tumor doubling times were increased. The tumor inhibition effect in the HCPT-loaded nanosphere-treated group was significantly higher than that of the HCPT-treated group (p < 0.01). Tumor inhibition in the control group by PEG-PBLG nanoparticles was not observed (p > 0.05).

Conclusion

Compared to the HCPT- and control-treated groups, the HCPT-loaded nanoparticle-treated group showed a more sustained release, a longer circulation time, increased delivery to tissue, and an enhanced anticancer effect. HCPT-loaded nanoparticles appear to change the pharmacokinetic behavior of HCPT in vivo.

Troxacitabine in leukemia

Troxacitabine (Troxatyl; BCH-4556; (-)-2'-deoxy-3'-oxacytadine) is the first synthetic l-nucleoside enantiomer to demonstrate broad spectrum cytotoxic activity. It was obtained by exchanging the sulphur endocyclic atom with oxygen in the structure of lamivudine, following the discovery that this agent had cytotoxic, as well as anti-viral activity. The unique "unnatural" stereochemistry of troxacitabine has produced impressive cytotoxic potency against a wide range of malignancies in the laboratory which led to its selection for clinical development. The initial trials with troxacitabine have established its efficacy in both solid and haematological malignancies, including those resistant to ara-C (cytarabine). This review will consider troxacitabine in terms of its pharmacology, mode of action, pharmacokinetics, toxicities, and clinical efficacy.

Evaluation of thel-stereoisomeric nucleoside analog troxacitabine for the treatment of acute myeloid leukemia

Troxacitabine (BCH-4556; [-]-2'-deoxy-3'-oxacytidine) is a synthetic dioxolane that represents the first nucleoside analog with an L-isomer configuration to have shown important cytotoxic activity. Troxacitabine was obtained by exchanging the sulfur endocyclic atom with oxygen in the structure of lamivudine (3TC). Its unnatural stereochemistry renders it insensitive to some mechanisms of resistance of tumor cells to D-nucleosides, such as deamination by deoxycytidine deaminase and decreased active uptake by nucleoside transporters. These characteristics make troxacitabine a suitable alternative for patients with acute myelogenous leukemia as a potential way for overcoming resistance to ara-C therapy, which is the mainstay of acute myelogenous leukemia therapy at present. Clinically significant activity has been reported in Phase I studies in patients with advanced hematologic malignancies and has prompted troxacitabine to enter a series of Phase II trials in patients with refractory and relapsed acute myelogenous leukemia.