Detection of nanocarrier potentiation on drug induced phospholipidosis in cultured cells and primary hepatocyte spheroids by high content imaging and analysis.

Considerable effort has been made to develop nanocarriers for controlled drug delivery over the last decade, while it remains unclear how the strength of adverse drug effect will be altered when a drug is loaded on the nanocarrier. Drug-induced phospholipidosis (DIP) is characterized with excessive accumulation of phospholipids in cells and is common for cationic amphiphilic drugs (CAD). Previously, we have reported that PEGylated graphene oxide (PEG-GO) loaded with several CAD can potentiate DIP. In current study, we extended our study on newly identified phospholipidosis (PLD) inducers that had been identified from the Library of Pharmacologically Active Compounds (LOPAC), to investigate if PEO-GO loaded with these CAD can alter DIP. Twenty-two CAD were respectively loaded on PEG-GO and incubated with RAW264.7, a macrophage cell line. The results showed that when a CAD was loaded on PEG-GO, its strength of PLD induction can be enhanced, unchanged or attenuated. PEG-GO loaded with Ifenprodil exhibited the highest PEG-GO potentiation effect compared to Ifenprodil treatment alone in RAW264.7 cells, and this effect was confirmed in human hepatocellular carcinoma HepG2, another cell line model for PLD induction. Primary hepatocyte culture and spheroids mimicking in vivo conditions were used to further validate nanocarrier potentiation on DIP by Ifenprodil. Stronger phospholipid accumulation was found in PEG-GO/Ifenprodil treated hepatocytes or spheroids than Ifenprodil treatment alone. Therefore, evidences were provided by us that nanocarriers may increase the adverse drug effects and guidance by regulatory agencies need to be drafted for the safe use of nanotechnology in drug delivery.

Mitochondria-targeted platinum(ii) complexes: dual inhibitory activities on tumor cell proliferation and migration/invasion via intracellular trafficking of ß-catenin.

Mitochondria-targeted therapy is an alternative strategy for cancer therapy and may overcome the problems of metastasis and drug resistance that usually occur in conventional treatment. In this work, we demonstrate the mitochondria-targeted delivery of a cationic cyclometalated platinum(ii) complex, PIP-platin, in cancer cells. PIP-platin showed selective delivery and accumulation in the mitochondria and exhibited toxicity against a variety of tumor cell lines. The mitochondria were disrupted by PIP-platin, along with the generation of reactive oxygen species, depolarization of mitochondrial membrane potential, release of cytochrome c and necrosis. Interestingly, PIP-platin can promote cell adhesion within several hours and the cells became hard to dislodge from the culture plate. A wound healing assay, transwell migration/invasion assay and 3D spheroid migration assay all demonstrated that PIP-platin can inhibit cell migration/invasion. To illustrate the associated mechanisms, we investigated the intracellular trafficking of ß-catenin, a central protein in the regulation of cell adhesion, and gene transcription for cell proliferation. Upon treatment with PIP-platin, this protein can translocate onto the plasma membrane for increased cell adhesion. In addition, PIP-platin was demonstrated to efficiently inhibit Wnt signaling by blocking the translocation of ß-catenin into the nuclei, thereby preventing cell proliferation. We demonstrate that, accordingly, PIP-platin has remarkable potential for intracellular delivery in mitochondria and has inhibitory effects on cancer cell proliferation and migration/invasion through ß-catenin, and may therefore be exploited as a dual-functional antitumor drug candidate in cancer treatment.

Autophagy associated cytotoxicity and cellular uptake mechanisms of bismuth nanoparticles in human kidney cells.

Bismuth compounds have been used for treatment of bacterial infection, and recently bismuth nanoparticles (BiNP) were synthesized for imaging and diagnostic purpose, while safety concern of bismuth cannot be ignored. Here, we prepared ultrasmall BiNP and showed an enhanced tumor imaging, but BiNP revealed a differentiated cytotoxicity in human embryonic kidney 293 cells (HEK293) compared to other cell types. For the first time, we found that BiNP can induce autophagy, shown as the increase of monodansylcadaverine fluorescence staining and the amount of LC3II that can be inhibited by 3-MA. BiNP were capable of entering cells in a dose and time dependent manner by fluorescence and element detection methods BiNP were found to be localized in the cytoplasm observed by transmission electron microscopy and intracellular bismuth element confirmed by energy dispersive X-ray analysis. Using endocytic inhibitors, BiNP were found to require ATP and endosomal trafficking pathways for their cellular uptake. Internalized BiNP did not co-localize with EEA1, but co-localized with Lysotracker/LAMP1/LAMP2 at late time points, indicating BiNP may be retained in the non-early endosomal vacuoles and late endosomes. With our novel finding of bismuth induced autophagy and endocytic mechanisms, potential approaches may be applied to reduce the toxicity by bismuth.

From the Cover: Potentiation of Drug-Induced Phospholipidosis In Vitro through PEGlyated Graphene Oxide as the Nanocarrier.

Cationic amphiphilic drugs (CADs) are small molecules that can induce phospholipidosis (PLD), causing the intracellular accumulation of phospholipid in the lamellar bodies. Nanotechnology based drug delivery systems have been used widely, while it is unknown if drug-induced PLD (DIP) can be potentiated through drug retention by indigestible nanocarriers. Due to the high drug loading capacity of graphene, we investigated if PEGylated graphene oxide (PEG-GO) loaded with CAD could potentiate DIP. Tamoxifen induced the accumulation of NBD-PE, a fluorescence labeled phospholipid in human hepatoma HepG2 cells, while PEG-GO loaded with tamoxifen (PEG-GO/tamoxifen) further potentiated PLD. PEG-GO/tamoxifen induced more gene expression of PLD marker than tamoxifen alone. PEG-GO enhanced DIP was also observed for other CAD, indicating that nanocarrier potentiated DIP could be universal. More lamellar bodies were observed in PEG-GO/tamoxifen treated cells than tamoxifen alone by transmission electron microscopy. When compared with tamoxifen alone, PEG-GO/tamoxifen showed a delayed but potent PLD. In addition, the retarded PLD recovery by PEG-GO/tamoxifen indicated that the reversibility of DIP was interfered. Confocal microscopy revealed the increased number of lysosomes, greater expression of lysosomal associated membrane protein 2 (LAMP2) (a PLD marker), and an increase in the co-localization between lysosome/LAMP2 and NBD-PE by PEG-GO/tamoxifen rather than tamoxifen alone. Finally, we found that PEG-GO or/and tamoxifen-induced PLD seemed to have no correlation with autophagy. This research suggests pharmaceutical companies and regulatory agencies that if nanoparticles are used as the vectors for drug delivery, the adverse drug effects may be further potentiated probably through the long-term accumulation of nanocarriers.

Comparative studies on the immunoregulatory effects of three polysaccharides using high content imaging system.

In this study, polysaccharides were isolated from Astragalus membranaceus, Ganoderma lucidum and Radix ophiopogonis and named APSII, GLPII and OGPII for comparison of their immunoactivities. MTT assay indicated that these polysaccharides increased the metabolic activity of Raw264.7 macrophages and induced cell differentiation to dendritic like cells. High content screening and mathematical modeling were used to quantify the cell irregularity, a hallmark of cell differentiation by polysaccharides. The results showed that GLPII increased cell irregularity, but APSII and OGPII had slightly less effects. Imaging analysis also revealed that polysaccharides inhibited cell proliferation while inducing the cell differentiation. In addition, APSII and GLPII but not OGPII induced NO production and enhanced cell phagocytic ability. Interestingly, inducible nitric oxide synthase inhibitor blocked polysaccharide-enhanced phagocytosis, indicating NO production is crucial for macrophages to acquire phagocytic ability, which was further confirmed by correlation studies. APSII and GLPII significantly promoted the maturation of macrophages by the increase in the expression of MHCII, CD40, CD80 and CD86, while OGPII had less effects. In summary, we have suggested a practical and economical method to quantify macrophage differentiation (irregularity) induced by polysaccharides for quality assurance and have found the role of NO production on macrophage phagocytic ability.