Chang Su

Gefitinib loaded folate decorated bovine serum albumin conjugated carboxymethyl-beta- cyclodextrin nanoparticles enhance drug delivery and attenuate autophagy in folate receptor-positive cancer cells

BackgroundActive targeting endocytosis mediated by the specific interaction between folic acid and its receptor has been a hotspot in biological therapy of many human cancers. Various studies have demonstrated that folate and its conjugates could facilitate the chemotherapeutic drug delivery into folate receptor (FR)-positive tumor cells in vitro and in vivo. In order to utilize FA-FR binding specificity to achieve targeted delivery of drugs into tumor cells, we prepared Gefitinib loaded folate decorated bovine serum albumin conjugated carboxymethyl-?-cyclodextrin nanoparticles for enhancing drug delivery in cancer cells. On this context, the aim of our study was to develop a novel nano-delivery system for promoting tumor-targeting drug delivery in folate receptor-positive Hela cells.ResultsWe prepared folic acid (FA)-decorated bovine serum albumin (BSA) conjugated carboxymethyl-?-cyclodextrin (CM-?-CD) nanoparticles (FA-BSA-CM-?-CD NPs) capable of entrapping a hydrophobic Gefitinib. It was observed that nanoparticles are monodisperse and spherical nanospheres with an average diameter of 90.2 nm and negative surface charge of -18.6 mV. FA-BSA-CM-ß-CD NPs could greatly facilitate Gefitinib uptake and enhance the toxicity to folate receptor-positive Hela cells. Under the reaction between FA and FR, Gefitinib loaded FA-BSA-CM-ß-CD NPs induced apoptosis of Hela cells through elevating the expression of caspase-3 and inhibited autophagy through decreasing the expressing of LC3. It also confirmed that clathrin-mediated endocytosis and macropinocytosis exerted great influence on the internalization of both NPs.ConclusionsThese results demonstrated that FA may be an effective targeting molecule and FA-BSA-CM-ß-CD NPs provided a new strategy for the treatment of human cancer cells which over-expressed folate receptors.

Hyaluronic acid-coated chitosan nanoparticles induce ROS-mediated tumor cell apoptosis and enhance antitumor efficiency by targeted drug delivery via CD44

BackgroundA targeted drug nanoparticle (NP) delivery system has shown potential as a possible cancer treatment. Given its merits, such as its selective distribution at tumor sites and its controllable drug release, drug-loaded NPs can be effectively delivered to selected organs and targeted cells, thus enhancing its antitumor efficiency and reducing its toxicity.MethodsWe reported that hyaluronic acid (HA)-coated chitosan NPs promoted the drug delivery of 5-fluorouracil (5-Fu) into tumor cells that highly expressed CD44.ResultsOur new findings suggested that HA-coated chitosan NPs enhanced drug accumulation by effectively transporting NPs into CD44-overexpressed tumor cells, and they also resulted in mitochondrial damage induced by the production of reactive oxygen species (ROS). Compared to free drug and uncoated NPs, HA-coated chitosan NPs exhibited stronger inhibition rates and induced obvious apoptosis in CD44-overexpressed A549 cells.ConclusionsBiocompatible and biodegradable HA-coated chitosan NPs were developed to encapsulate a chemotherapeutic drug (5-Fu) to enhance drug accumulation in tumor cells and to improve the agent’s antitumor efficiency by offering targeted drug delivery via CD44.

Intracellular targeted co-delivery of shMDR1 and gefitinib with chitosan nanoparticles for overcoming multidrug resistance

Nowadays, multidrug resistance and side effects of drugs limit the effectiveness of chemotherapies in clinics. P-glycoprotein (P-gp) (MDR1), as a member of the ATP-binding cassette family, acts on transporting drugs into cell plasma across the membrane of cancer cells and leads to the occurrence of multidrug resistance, thus resulting in the failure of chemotherapy in cancer. The main aims of this research were to design a nanodelivery system for accomplishing the effective co-delivery of gene and antitumor drug and overcoming multidrug resistance effect. In this study, shMDR1 and gefitinib-encapsulating chitosan nanoparticles with sustained release, small particle size, and high encapsulation efficiency were prepared. The serum stability, protection from nuclease, and transfection efficiency of gene in vitro were investigated. The effects of co-delivery of shMDR1 and gefitinib in nanoparticles on reversing multidrug resistance were also evaluated by investigating the cytotoxicity, cellular uptake mechanism, and cell apoptosis on established gefitinib-resistant cells. The results demonstrated that chitosan nanoparticles entrapping gefitinib and shMDR1 had the potential to overcome the multidrug resistance and improve cancer treatment efficacy, especially toward resistant cells.

Preparation of biocompatible heat-labile enterotoxin subunit B-bovine serum albumin nanoparticles for improving tumor-targeted drug delivery via heat-labile enterotoxin subunit B mediation.

Heat-labile enterotoxin subunit B (LTB) is a non-catalytic protein from a pentameric subunit of Escherichia coli. Based on its function of binding specifically to ganglioside GM1 on the surface of cells, a novel nanoparticle (NP) composed of a mixture of bovine serum albumin (BSA) and LTB was designed for targeted delivery of 5-fluorouracil to tumor cells. BSA-LTB NPs were characterized by determination of their particle size, polydispersity, morphology, drug encapsulation efficiency, and drug release behavior in vitro. The internalization of fluorescein isothiocyanate-labeled BSA-LTB NPs into cells was observed using fluorescent imaging. Results showed that BSA-LTB NPs presented a narrow size distribution with an average hydrodynamic diameter of approximately 254±19 nm and a mean zeta potential of approximately −19.95±0.94 mV. In addition, approximately 80.1% of drug was encapsulated in NPs and released in the biphasic pattern. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that BSA-LTB NPs exhibited higher cytotoxic activity than non-targeted NPs (BSA NPs) in SMMC-7721 cells. Fluorescent imaging results proved that, compared with BSA NPs, BSA-LTB NPs could greatly enhance cellular uptake. Hence, the results indicate that BSA-LTB NPs could be a potential nanocarrier to improve targeted delivery of 5-fluorouracil to tumor cells via mediation of LTB.

The role of c-Src in the invasion and metastasis of hepatocellular carcinoma cells induced by association of cell surface GRP78 with activated α2M

BackgroundEmerging data have suggested that cell surface GRP78 is a multifunctional receptor and has been linked to proliferative and antiapoptotic signaling cascades. Activated α2−macroglobin (α2M*) is a natural circulating ligand of cell surface GRP78. Association of cell surface GRP78 with α2M* is involved in the regulation of cell proliferation, survival and apoptosis in human cancers.MethodsThe invasion and metastasis of HCC cells were examined using transwell and wound healing assay; Cell surface expression of GRP78 was detected by in cell western assay. Translocation of GRP78 from cytosol to cell surface was observed by transfection of GRP78-EGFP plus TRIRC-WGA staining. The levels of Src, phosphor-Src, FAK, phospho-FAK, EGFR, phospho-EGFR, phospho-Cortactin, phospho-Paxillin were determined by western blot. Cell surface expression of GRP78 in HCC tissue samples was observed by immunofluorescence. The distribution of Paxillin and Cortactin in HCC cells was also observed by immunofluorescence. The interaction between GRP78 and Src were detected by far-western blot, co-immunoprecipitation and GST pulldown. GRP78 mRNA was detected by RT-PCR.ResultsIn the current study, we showed that association of cell surface GRP78 with α2M* stimulated the invasion and metastasis of HCC. Cell surface GRP78 could interact directly with c-Src, promoted the phosphorylation of c-Src at Y416. Inhibition of the tyrosine kinase activity of c-Src with PP2 reverted the stimulatory effect caused by association of cell surface GRP78 with α2M*. Moreover, association of cell surface GRP78 with α2M* facilitates the interaction between EGFR and c-Src and consequently phosphorylated EGFR at Y1101 and Y845, promoting the invasion and metastasis of HCCs. However, inhibition of the tyrosine kinase of c-Src do not affect the interaction between EGFR and Src.Conclusionc-Src plays a critical role in the invasion and metastasis of HCC induced by association of cell surface GRP78 with α2M*. Cell surface GRP78 directly binds and phosphorylates c-Src. As a consequence, c-Src phosphorylated EGFR, promoting the invasion and metastasis of HCCs.

Triphenyl Phosphine-Functionalized Chitosan Nanoparticles Enhanced Antitumor Efficiency Through Targeted Delivery of Doxorubicin to Mitochondria

Mitochondria as an important organ in eukaryotic cells produced energy through oxidative phosphorylation and also played an important role in regulating the apoptotic signal transduction process. Importantly, mitochondria like nuclei also contained the functional DNA and were very sensitive to anticancer drugs which could effectively inhibit the synthesis of nucleic acid, especially the production of DNA. In this work, we designed novel triphenyl phosphine (TPP)-conjugated chitosan (CS) nanoparticles (NPs) for efficient drug delivery to cell mitochondria. The results showed that compared with free doxorubicin (Dox), Dox-loaded TPP-NPs were specifically distributed in mitochondria of tumor cells and interfered with the function of mitochondria, thus resulted in the higher cytotoxicity and induced the significant cell apoptosis effect. Taken together, triphenyl phosphine-conjugated chitosan nanoparticles may become a promising mitochondria-targeting nanocarrier candidate for enhancing antitumor effects.

Nanoparticle Delivery of Artesunate Enhances the Anti-tumor Efficiency by Activating Mitochondria-Mediated Cell Apoptosis

Artemisinin and its derivatives were considered to exert a broad spectrum of anti-cancer activities, and they induced significant anti-cancer effects in tumor cells. Artemisinin and its derivatives could be absorbed quickly, and they were widely distributed, selectively killing tumor cells. Since low concentrations of artesunate primarily depended on oncosis to induce cell death in tumor cells, its anti-tumor effects were undesirable and limited. To obtain better anti-tumor effects, in this study, we took advantage of a new nanotechnology to design novel artesunate-loaded bovine serum albumin nanoparticles to achieve the mitochondrial accumulation of artesunate and induce mitochondrial-mediated apoptosis. The results showed that when compared with free artesunate’s reliance on oncotic death, artesunate-loaded bovine serum albumin nanoparticles showed higher cytotoxicity and their significant apoptotic effects were induced through the distribution of artesunate in the mitochondria. This finding indicated that artesunate-loaded bovine serum albumin nanoparticles damaged the mitochondrial integrity and activated mitochondrial-mediated cell apoptosis by upregulating apoptosis-related proteins and facilitating the rapid release of cytochrome C.

Chitosan nanoparticle-mediated co-delivery of shAtg-5 and gefitinib synergistically promoted the efficacy of chemotherapeutics through the modulation of autophagy

BackgroundAutophagy reportedly plays vital and complex roles in many diseases. During times of starvation or energy deficiency, autophagy will occur at higher levels to provide cells with the nutrients or energy necessary to survive in stressful conditions. Some anti-cancer drugs induce protective autophagy and reduce cell apoptosis. Autophagy can adversely affect apoptosis, and blocking autophagy will increase the sensitivity of cells to apoptosis signals.MethodsWe designed chitosan nanoparticles (NPs) to promote the co-delivery of gefitinib (an anti-cancer drug) and shRNA-expressing plasmid DNA that targets the Atg-5 gene (shAtg-5) as an autophagy inhibitor to improve anti-cancer effects and autophagy mediation.ResultsThe results showed that when compared to treatment with a single drug, chitosan NPs were able to facilitate the intracellular distribution of NPs, and they improved the transfection efficiency of gene in vitro. The co-delivery of gefitinib and shAtg-5 increased cytotoxicity, induced significant apoptosis through the prohibition of autophagy, and markedly inhibited tumor growth in vivo.ConclusionsThe co-delivery of gefitinib/shAtg-5 in chitosan NPs produced superior anti-cancer efficacy via the internalization effect of NPs, while blocking autophagy with shAtg-5 enhanced the synergistic antitumor efficacy of gefitinib.

Nanoparticles inhibit cancer cell invasion and enhance antitumor efficiency by targeted drug delivery via cell surface-related GRP78

Nanoparticles (NPs) which target specific agents could effectively recognize the target cells and increase the stability of chemical agents by encapsulation. As such, NPs have been widely used in cancer treatment research. Recently, over 90% of treatment failure cases in patients with metastatic cancer were attributed to resistance to chemotherapy. Surface-exposed glucose-regulated protein of 78 kDa (GRP78) is expressed highly on many tumor cell surfaces in many human cancers and is related to the regulation of invasion and metastasis. Herein, we report that NPs conjugated with antibody against GRP78 (mAb GRP78-NPs) inhibit the adhesion, invasion, and metastasis of hepatocellular carcinoma (HCC) and promote drug delivery of 5-fluorouracil into GRP78 high-expressed human hepatocellular carcinoma cells. Our new findings suggest that mAb GRP78-NPs could enhance drug accumulation by effectively transporting NPs into cell surface GRP78-overexpressed human hepatocellular carcinoma cells and then inhibit cell proliferation and viability and induce cell apoptosis by regulating caspase-3. In brief, mAb GRP78-NPs effectively inhibit cancer cell invasion and enhance antitumor efficiency by targeted drug delivery.

GRP78 confers the resistance to 5-FU by activating the c-Src/LSF/TS Axis in hepatocellular carcinoma

5-FU is a common first-line chemotherapeutic drug for the treatment of hepatocellular carcinoma. However the development of acquired resistance to 5-FU confines its clinical usages. Although this phenomenon has been the subject of intense investigation, the exact mechanism of acquired resistance to 5-FU remains elusive. Here, we report that over-expression of GRP78 contributes to acquired resistance to 5-FU in HCC by up-regulating the c-Src/LSF/TS axis. Moreover, we found that the resistance to 5-FU conferred by GRP78 is mediated by its ATPase domain. The ATPase domain differentially increased the expression of LSF, TS and promoted the phosphorylation of ERK and Akt. We further identified that GRP78 interacts physically with c-Src through its ATPase domain and promotes the phosphorylation of c-Src, which in turn increases the expression of LSF in the nucleus. Together, GRP78 confers the resistance to 5-FU by up-regulating the c-Src/LSF/TS axis via its ATPase domain.