Design And Characterisation Of Novel Sorafenib-Loaded Carbon Nanotubes With Distinct Tumour-Suppressive Activity In Hepatocellular Carcinoma

PURPOSE

Over the past 30 years, no consistent survival benefits have been recorded for anticancer agents of advanced hepatocellular carcinoma (HCC), except for the multikinase inhibitor sorafenib (Nexavar®), which clinically achieves only ~3 months overall survival benefit. This modest benefit is attributed to limited aqueous solubility, slow dissolution rate and, consequently, limited absorption from the gastrointestinal tract. Thus, novel formulation modalities are in demand to improve the bioavailability of the drug to attack HCC in a more efficient manner. In the current study, we aimed to design a novel sorafenib-loaded carbon nanotubes (CNTs) formula that is able to improve the therapeutic efficacy of carried cargo against HCC and subsequently investigate the antitumour activity of this formula.

MATERIALS AND METHODS

Sorafenib was loaded on functionalized CNTs through physical adsorption, and an alginate-based method was subsequently applied to microcapsulate the drug-loaded CNTs (CNTs-SFN). The therapeutic efficacy of the new formula was estimated and compared to that of conventional sorafenib, both in vitro (against HepG2 cells) and in vivo (in a DENA-induced HCC rat model).

RESULTS

The in vitro MTT anti-proliferative assay revealed that the drug-loaded CNTs formula was at least two-fold more cytotoxic towards HepG2 cells than was sorafenib itself. Moreover, the in vivo animal experiments proved that our innovative formula was superior to conventional sorafenib at all assessed end points. Circulating AFP-L3% was significantly decreased in the CNTs-SFN-MCs-treated group (14.0%) in comparison to that of the DENA (40.3%) and sorafenib (38.8%) groups. This superiority was further confirmed by Western blot analysis and immunofluorescence assessment of some HCC-relevant biomarkers.

CONCLUSION

Our results firmly suggest the distinctive cancer-suppressive nature of CNTs-SFN-MCs, both against HepG2 cells in vitro and in a DENA-induced HCC rat model in vivo, with a preferential superiority over conventional sorafenib.

Progesterone side-chain degradation by some species of Aspergillus flavus group

Seventy isolates belonging to 6 species and one variety of A. flavus group were shown to degrade the progesterone side-chain to yield delta 4-androstene-3,17-dione and testosterone. The isolates of five species (A. flavo-furcatis, A. flavus, A. oryzae, A. parasiticus and A. tamarii) possessed enzyme systems catalyzing the opening of ring D and formed testololactone as final steroid metabolite in addition to their ability to produce the above mentioned two products. 11 beta-Hydroxy-delta 4-androstene-3,17-dione was formed by only A. flavus and A. tamarii while 11 beta-hydroxytestosterone was produced by A. flavo-furcatis, A. parasiticus and A. subolivaceus. The chromatographic resolution of the mixture products obtained (when the selective isolate of each species reacted with 1 g of progesterone) revealed that 60-75% of progesterone was converted into delta 4-androstene-3,17-dione (8-30%), testosterone (7-33%), testololactone (14-37%) and other products (3-40%). The most bioconversion activity was exhibited by A. oryzae, followed by A. parasiticus. The highest values of delta 4-androstene-3,17-dione (30% of added progesterone) and testosterone (33%) were formed by A. flavus var. columnaris while those of testololactone (37%) were produced by A. oryzae. A systematic variation could be observed between the different tested species of A. flavus group with respect to the transformation reactions of progesterone. Comparative biotransformation results showed that essential differences exist between the tested species in this group; this biochemical differentiation may supplement the morphological and other physiological criteria used in the identification of the different species in the A. flavus group.

Progesterone transformation as a diagnostic feature in the classification of the Aspergillus niger group

Fifty-five isolates of nine species and two species varieties (5 isolates each) of the Aspergillus niger group were tested for progesterone transformation. Generally, all isolates of the different species transformed progesterone to 21-hydroxyprogesterone. In addition, the isolates of seven species have the capacity to hydroxylate progesterone to 11 alpha-hydroxyprogesterone. A systematic variation could be observed between the tested species of the Aspergillus niger group with respect to the transformation reactions of progesterone. Comparative biotransformation results showed that essential differences exist between the species of this group, where the different isolates of individual species always produce one or more identical products. This biochemical differentiation may supplement the morphological criteria used in the classification of this group of fungi.