Introduction:
Herein, a hyaluronic acid (HA)-coated redox-sensitive chitosan-based nanoparticle, HA(HECS-ss-OA)/GA, was successfully developed for tumor-specific intracellular rapid delivery of gambogic acid (GA).
Materials and methods:
The redox-sensitive polymer, HECS-ss-OA, was prepared through a well-controlled synthesis procedure with a satisfactory reproducibility and stable resulted surface properties of the assembled cationic micelles. GA was solubilized into the inner core of HECS-ss-OA micelles, while HA was employed to coat outside HECS-ss-OA/GA for CD44-mediated active targeting along with protection from cation-associated in vivo defects. The desirable redox-sensitivity of HA(HECS-ss-OA)/GA was demonstrated by morphology and particle size changes alongside in vitro drug release of nanoparticles in different simulated reducing environments.
Results:
The results of flow cytometry and confocal microscopy confirmed the HA-receptor mediated cellular uptake and burst drug release in highly reducing cytosol of HA(HECS-ss-OA)/GA. Consequently, HA(HECS-ss-OA)/GA showed the highest apoptosis induction and cytotoxicity over the non-sensitive (HA(HECS-cc-OA)/GA) and HA un-coated (HECS-ss-OA/GA) controls against A549 NSCLC model both in vitro and in vivo. Furthermore, a diminished systemic cytotoxicity was observed in HA(HECS-ss-OA)/GA treated mice compared with those treated by HA un-coated cationic ones and GA solution.
In a previous study, we found that the global genome organizer Special AT-rich binding protein 1 (SATB1) is highly expressed in mesenchymal-derived human osteosarcoma U2OS cells and that the knock-down of SATB1 results in the inhibition of cell proliferation. The present study was aimed at investigating the effect of silencing SATB1 on cell migration, invasion, apoptosis and resistance to the chemotherapeutic drug arsenic trioxide. Cell migration and invasion were detected by wound-healing assays and trans-well invasion assays, respectively. Cell apoptosis was analyzed by an in situ Cell Death Detection POD Kit, based on terminal deoxynucleotydyl transferase mediated dUTP nick-end labeling (TUNEL) staining and mRNAs were analyzed by real time qRT-PCR. We found that cell migration and invasion were inhibited and that the proportion of apoptotic cells and sensitivities to the chemotherapeutic drug arsenic trioxide were enhanced by knockdown of SATB1 in U2OS cells. Furthermore, mRNA of ABCC1 and ABCG2 were decreased strikingly after SATB1 silencing. It was concluded that the elevated expression of SATB1 in U2OS cells contributes to maintenance of the malignant phenotype and resistance to chemotherapeutic drugs ATO, suggesting that silencing SATB1 in the cells might improve the effects of arsenic trioxides in the treatment of osteosarcoma in which SATB1 is over-expressed and that ABCC1 and ABCG2 were involved in SATB1 mediated resistance of U2OS cells to ATO.
Prostaglandin E1 (PGE1) is a member of the prostaglandins and has a variety of cardiovascular protective effects. Increasing attention has been paid to the anti-inflammation activity of PGE1, but little direct evidence has been found. We investigated the effects of PGE1 on cell adhesion and inflammation and the mechanisms responsible for this activity in tumor necrosis factor (TNF)-treated human umbilical vein endothelial cells. Results demonstrated that pretreatment with PGE1 decreased the adhesion between vascular endothelial cells and monocytes, reduced the expression of vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and E-selectin in vascular endothelial cells. In addition, PGE1 suppressed TNF-induced NF-kappaB activation and production of reactive oxygen species. We concluded that PGE1 suppressed the vascular inflammatory process, which might be closely related to the inhibition of reactive oxygen species and NF-kappaB activation in human umbilical vein endothelial cells.
Currently, the most prominent barrier to the success of orally delivered paclitaxel (PTX) is the extremely limited bioavailability of delivered therapeutic. In light of this issue, an amphiphilic sulfhydrylated N-deoxycholic acid-N,O-hydroxyethyl chitosan (TGA-DHC) was synthesized to improve the oral bioavailability of PTX. First, TGA-DHC demonstrated substantial loading of PTX into the inner hydrophobic core. A desirable enhancement in the bioavailability of PTX by TGA-DHC was verified by pharmacokinetic studies on rats against Taxol and non-sulfhydrylated DHC micelles. Moreover, cellular uptake studies revealed significant accumulation of TGA-DHC micelles encapsulating PTX or rhodamine-123 into Caco-2 cells via clathrin/caveolae-mediated endocytosis and inhibition of P-gp efflux of substrates. The results of the Caco-2 transport study further confirmed the mechanistic basis of TGA-DHC efficacy; which was attributed to permeabilized tight junctions, clathrin-mediated transcytosis across the endothelium, and inhibition of P-gp. Finally, in vitro mucoadhesion investigations on freshly excised rat intestine intuitively confirmed increased intestinal retention of drug-loaded TGA-DHC through thiol-mediated mucoadhesion. TGA-DHC has demonstrated the capability to overcome what is perhaps the most prominent barrier to oral PTX efficacy, low bioavailability, and serves as a prominent platform for oral delivery of P-gp substrates.
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