Anticancer Activity, Mechanism, and Delivery of Allyl Isothiocyanate.

Allyl isothiocyanate (AITC) is a phytochemical that is abundantly present in cruciferous vegetables of the Brassicaceae family, such as cabbage, broccoli, mustard, wasabi, and cauliflower. The pungent taste of these vegetables is mainly due to the content of AITC present in these vegetables. AITC is stored stably in the plant as its precursor sinigrin (a type of glucosinolate), which is physically separated from myrosin cells containing myrosinase. Upon tissue disruption, myrosinase gets released and hydrolyzes the sinigrin to produce AITC and by-products. AITC is an organosulfur compound, both an irritant and toxic, but it carries pharmacological properties, including anticancer, antibacterial, antifungal, and anti-inflammatory activities. Despite the promising anticancer effectiveness of AITC, its clinical application still possesses challenges due to several factors, i.e., low aqueous solubility, instability, and low bioavailability. In this review, the anticancer activity of AITC against several cancer models is summarized from the literature. Although the mechanism of action is still not fully understood, several pathways have been identified; these are discussed in this review. Not much attention has been given to the delivery of AITC, which hinders its clinical application. However, the few studies that have demonstrated the use of nanotechnology to facilitate the delivery of AITC are addressed.

Mesobiliverdin IXα ameliorates osteoporosis via promoting osteogenic differentiation of mesenchymal stem cells.

Heme oxygenase-1 (HO-1) expression promotes osteogenesis, but the mechanisms remain unclear and therapeutic strategies using it to target bone disorders such as osteoporosis have not progressed. Mesobiliverdin IXα is a naturally occurring bilin analog of HO-1 catalytic product biliverdin IXα. Inclusion of mesobiliverdin IXα in the feed diet of ovariectomized osteoporotic mice was observed to increase femur bone volume, trabecular thickness and osteogenesis serum markers osteoprotegrin and osteocalcin and to decrease bone resorption serum markers cross-linked N-teleopeptide and tartrate-resistant acid phosphatase 5b. Moreover, in vitro exposure of human bone marrow mesenchymal stem cells to mesobiliverdin IXα enhanced osteogenic differentiation efficiency by two-fold over non-exposed controls. Our results imply that mesobiliverdin IXα promotes osteogenesis in ways that reflect the potential therapeutic effects of induced HO-1 expression in alleviating osteoporosis.

Eradication of Myrosinase-Tethered Cancer Cells by Allyl Isothiocyanate Derived from Enzymatic Hydrolysis of Sinigrin.

Sinigrin is present in significant amounts in cruciferous vegetables. Epidemiological studies suggest that the consumption of such vegetables decreases the risk of cancer, and the effect is attributed mainly to allyl isothiocyanate (AITC), a hydrolysis product of sinigrin catalyzed by myrosinase. Anticancer activity of AITC has been previously investigated for several cancer models, but less attention was paid to delivering AITC on the target site. In this study, the gene sequences of core streptavidin (coreSA) and myrosinase (MYR) were cloned in a pET-30a(+) plasmid and transformed into BL21(DE3) E. coli competent cells. The MYR-coreSA chimeric protein was expressed and purified using immobilized metal affinity chromatography and further characterized by gel electrophoresis, Western blot, and enzyme activity assay. The purified MYR-coreSA chimeric protein was tethered on the outer membrane of biotinylated adenocarcinoma A549 cells and then treated with various concentrations of sinigrin. Our results showed that 20 µM of sinigrin inhibited the growth of A549 cells tethered with myrosinase by ~60% in 48 h. Furthermore, the levels of treated cells undertaken apoptosis were determined by Caspase-3/7 activation and Annexin-V. In summary, sinigrin harnessed like a prodrug catalyzed by myrosinase to the production of AITC, which induced cell apoptosis and arrested the growth of lung cancer cells.

Less phagocytosis of viral vectors by tethering with CD47 ectodomain.

Many viral vectors, which are effective when administrated in situ, lack efficacy when delivered intravenously. The key reason for this is the rapid clearance of the viruses from the blood circulation via the immune system before they reach target sites. Therefore, avoiding their clearance by the immune system is essential. In this study, lentiviral vectors were tethered with the ectodomain of self-marker protein CD47 to suppress phagocytosis via interacting with SIRPα on the outer membrane of macrophage cells. CD47 ectodomain and core-streptavidin fusion gene (CD47ED-coreSA) was constructed into pET-30a(+) plasmid and transformed into Lemo21 (DE3) competent E. coli cells. The expressed CD47ED-coreSA chimeric protein was purified by cobalt-nitrilotriacetate affinity column and characterized by SDS-PAGE and western blot. The purified chimeric protein was anchored on biotinylated lentivirus via biotin-streptavidin binding. The CD47ED-capped lentiviruses encoding GFP were used to infect J774A.1 macrophage cells to assess the impact on phagocytosis. Our results showed that the overexpressed CD47ED-coreSA chimeric protein was purified and bound on the surface of biotinylated lentivirus which was confirmed via immunoblotting assay. The process to produce biotinylated lentivirus did not affect native viral infectivity. It was shown that the level of GFP expression in J774A.1 macrophages transduced with CD47ED-lentiviruses was threefold lower in comparison to control lentiviruses, indicating an antiphagocytic effect triggered by the interaction of CD47ED and SIRPα. Through the test of blocking antibodies against CD47ED and/or SIRPα, it was confirmed that the phagocytosis inhibition was mediated through the CD47ED-SIRPα axis signaling. In conclusion, surface immobilization of CD47ED on lentiviral vectors inhibits their phagocytosis by macrophages. The chimeric protein of CD47 ectodomain and core-streptavidin is effective in mediating the surface binding and endowing the lentiviral nanoparticles with the antiphagocytic property.

Polymeric Nanovectors Incorporated with Ganciclovir and HSV-tk Encoding Plasmid for Gene-Directed Enzyme Prodrug Therapy.

In the area of gene-directed enzyme prodrug therapy (GDEPT), using herpes simplex virus thymidine kinase (HSV-tk) paired with prodrug ganciclovir (GCV) for cancer treatment has been extensively studied. It is a process involved with two steps whereby the gene (HSV-tk) is first delivered to malignant cells. Afterward, non-toxic GCV is administered to that site and activated to cytotoxic ganciclovir triphosphate by HSV-tk enzyme expressed exogenously. In this study, we presented a one-step approach that both gene and prodrug were delivered at the same time by incorporating them with polymeric micellar nanovectors. GCV was employed as an initiator in the ring-opening polymerization of ε-caprolactone (ε-CL) to synthesize hydrophobic GCV-poly(caprolactone) (GCV-PCL), which was furthered grafted with hydrophilic chitosan to obtain amphiphilic polymer (GCV-PCL-chitosan) for the fabrication of self-assembled micellar nanoparticles. The synthesized amphiphilic polymer was characterized using Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Micellar prodrug nanoparticles were analyzed by dynamic light scattering, zeta potential, critical micelle concentration, and transmission electron microscopy. Polymeric prodrug micelles with optimal features incorporated with HSV-tk encoding plasmids were cultivated with HT29 colorectal cancer cells and anticancer effectiveness was determined. Our results showed that prodrug GCV and HSV-tk cDNA encoded plasmid incorporated in GCV-PCL-chitosan polymeric nanocarriers could be delivered in a one-step manner to HT-29 cells and triggered high cytotoxicity.

Mesenchymal stem cells anchored with thymidine phosphorylase for doxifluridine-mediated cancer therapy.

Many tumors express thymidine phosphorylase (TYMP) with various levels, however due to tumor heterogeneity, the amount of TYMP is usually not enough to convert prodrug doxifluridine (5'-DFUR) to toxic drug 5-fluorouracil (5-FU). Since human mesenchymal stem cells (hMSCs) have unique features of tumor-tropism and low immunogenicity, the purpose of this study is to use mesenchymal stem cells as carriers to deliver TYMP to cancer cells and then trigger their death by administrating doxifluridine. First, the TYMP gene sequence and core streptavidin (core SA) were constructed into pET-30a(+) plasmid. After bacterial transformation and colony screening, TYMP-SA fusion protein was expressed by IPTG induction and purified by immobilized metal affinity chromatography and characterized by SDS-PAGE and western blot with a clear band at 75 kDa. The characterized TYMP-SA was further anchored on the cell membrane of biotinylated hMSCs via biotin-streptavidin binding. hMSCs anchored with TYMP-SA were then co-cultured with adenocarcinoma A549 cells (with different ratios) and treated with 100 µM prodrug doxifluridine over the course of four days. Our results showed that a 2 : 1 ratio led to the eradication of A549 cells at the end of the experiment with less than 5% confluency, in comparison with the 1 : 1 and 1 : 2 ratios which still had about 13% and 20% confluency respectively. In conclusion, harnessing hMSCs as cell carriers for the delivery of TYMP enzyme to cancer cells could lead to significant cell death post-treatment of the prodrug doxifluridine.

Blockade of macrophage adhesion to CD200-treated polystyrene culture surface.

CD200 is an anti-inflammatory transmembrane glycoprotein in the immunoglobulin superfamily. The interaction of CD200 and its receptor CD200R has shown to inhibit inflammatory response of myeloid cells to foreign materials. The purpose of this study is to create a CD200 immobilized biomaterial surface through polydopamine coating to suppress macrophage cell adhesion and reduce inflammatory cytokine secretion accordingly by macrophages. In this study, tissue-culture treated polystyrene (TCPS) surface was modified with biotin through polydopamine coating. Purified CD200-streptavidin fusion protein was then immobilized onto the biotinylated TCPS surface through the high affinity between biotin and streptavidin. Mouse J774A.1 macrophages were seeded on CD200-immobilized TCPS surface to evaluate the effect of CD200 on preventing macrophage attachment. The effects of CD200-immobilized TCPS surface on pro-inflammatory cytokine secretion from J774A.1 macrophages were measured by enzyme-linked immunosorbent assay. As a result, CD200-immobilized TCPS surface suppressed macrophage attachment for up to 9 hr. The level of IL-6 and TNF-α secreted from J774A.1 macrophages interacted with CD200-coated TCPS surface was reduced by 36.3% and 32.4%, respectively.

Efficient Expression of Soluble Recombinant Protein Fused with Core-Streptavidin in Bacterial Strain with T7 Expression System.

The limited amount of fusion protein transported into cytosol milieu has made it challenging to obtain a sufficient amount for further applications. To avoid the laborious and expensive task, T7 promoter-driving pET-30a(+) coding for chimeric gene of thymidine phosphorylase and core streptavidin as a model system was constructed and transformed into a variety of E. coli strains with T7 expression system. Our results demonstrated that the pET-30a(+)-TP-coreSA/Lemo21(DE3) system is able to provide efficient expression of soluble TP-coreSA fusion protein for purification. Moreover, the eluted TP-coreSA fusion protein tethered on biotinylated A549 carcinoma cells could effectively eliminate these malignant cells after administrating prodrug 5'-DFUR.

Diminution of Phagocytosed Micro/Nanoparticles by Tethering with Immunoregulatory CD200 Protein.

CD200 is known as an anti-inflammatory transmembrane glycoprotein in the immunoglobulin superfamily. CD200 interacts with its receptor CD200R which is highly expressed on myeloid cells such as macrophages and neutrophils. CD200-CD200R interaction has known to reduce macrophage activation and chronic inflammation. To harness the immunomodulatory property of CD200 for surface modification, CD200-streptavidin fusion protein was expressed from bacteria transformed with pET20b plasmid encoded with CD200 extracellular domain and core streptavidin. The purified CD200-SA protein was bound to biotin-coated fluorescent polystyrene particles of various sizes ranging from 0.15 to 2 µm. THP-1 macrophages were cultivated with CD200-modified micro/nanoparticles in comparison with controls. Our results showed that both nano- and micro-sized particles decorated with CD200 decreased phagocytosis activities of THP-1 macrophages. Such diminution of phagocytosis was examined to be associated with downregulation of Toll-like receptor 4 (TLR4) expression on the surface of macrophages. Moreover, THP-1 macrophages treated with CD200-coated particles decreased the secretion of tumor necrosis factor-α (TNF-α).

Enhanced proliferation and differentiation of mesenchymal stem cells by astaxanthin-encapsulated polymeric micelles.

Astaxanthin is a highly potent antioxidant which can be extracted from Haematococcus pluvialis when cultivated and induced at high stress conditions. Due to astaxanthin's hydrophobicity, methoxypolyethylene glycol-polycaprolactone (mPEG-PCL) copolymer was synthesized to form polymeric micelles for the encapsulation of astaxanthin. Astaxanthin-loaded polymeric micelles were then used to examine the effects on the proliferation and differentiation of human mesenchymal stem cells (MSCs). Dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FT-IR) confirmed astaxanthin was encapsulated into mPEG-PCL micelles. Astaxanthin loading and encapsulation efficiency, determined by UV/Vis spectroscopy, were 3.27% and 96.67%, respectively. After 48 h, a total of 87.31% of astaxanthin was released from the polymeric micelles. The drug release profile was better fit by the Michaelis-Menten type model than the power law model. The MSC culture results showed that culture medium supplemented with 0.5 µg/mL astaxanthin-encapsulated polymeric micelles led to a 26.3% increase in MSC proliferation over an 8-day culture period. MSC differentiation results showed that 20 ng/mL astaxanthin-encapsulated polymeric micelles enhanced adipogenesis, chondrogenesis, and osteogenesis of MSCs by 52%, 106%, and 182%, respectively.

Extraction of cobalt(ii) by methyltrioctylammonium chloride in nickel(ii)-containing chloride solution from spent lithium ion batteries.

Spent lithium batteries contain valuable metals such as cobalt, copper, nickel, lithium, etc. After pretreatment and recovery of copper, only cobalt, nickel and lithium were left in the acid solution. Since the chemical properties of cobalt and nickel are similar, separation of cobalt from a solution containing nickel is technically challenging. In this study, Co(ii) was separated from Ni(ii) by chelating Co(ii) with chlorine ions, Co(ii) was then extracted from the aforementioned chelating complexes by methyltrioctylammonium chloride (MTOAC). The effects of concentrations of chlorine ions in the aqueous phase ([Cl-]aq), MTOAC concentrations in organic phase ([MTOAC]org), ratios of organic phase to aqueous phase (O/A), and the initial aqueous pH on cobalt separation were studied. The results showed that [Cl-]aq had a significant impact on cobalt extraction efficiency with cobalt extraction efficiency increasing rapidly with the increase in [Cl-]aq. The effect of initial pH on cobalt extraction efficiency was not significant when it varied from 1 to 6. Under the condition of [Cl-]aq = 5.5 M, [MTOAC]org = 1.3 M, O/A = 1.5, and pH = 1.0, cobalt extraction efficiency reached the maximum of 98.23%, and nickel loss rate was only 0.86%. The stripping rate of cobalt from Co(ii)-MTOAC complexes using diluted hydrochloric acid was 99.95%. By XRD and XRF analysis, the recovered cobalt was in the form of cobalt chloride with the purity of cobalt produced reaching 97.7%. The mode of cobalt extraction was verified to be limited by chemical reaction and the kinetic equation for cobalt extraction was determined to be: R (Co) = 4.7 × 10-3[MTOAC](org) 1.85[Co](aq) 1.25.

Migration of mesenchymal stem cells tethered with carbon nanotubes under a chemotactic gradient.

Carbon nanotubes (CNTs) have been extensively studied for photothermal ablation of malignant cells due to their ability to absorb near-infrared (NIR) laser light and convert it to thermal energy for the lysis of tumor cells. Functionalizing CNTs with tumor-targeting moieties can facilitate the delivery to tumor sites. Instead of using targeting moieties, mesenchymal stem cells (MSCs) have been considered as vehicles to deliver therapeutic agents to cancer cells. In this study, the effects of attaching CNTs to MSCs on cell migration in response to a chemotactic gradient were investigated. Multiwalled carbon nanotubes (MWCNTs) were functionalized with streptavidin-fluorescein isothiocyanate (SA-FITC). The surface of human MSCs was biotinylated by culturing MSCs with biotin-lipid containing medium. CNTs were then attached on the outer cell membrane of biotinylated MSCs through SA-biotin binding. Fluorescence microscopy confirmed CNTs were located on the surface of MSCs. Various amounts of CNTs anchored on the membrane of MSCs were used to examine the effects of CNTs on MSC proliferation and migration. Our transwell migration assay showed that 4.26 ng CNT per cell is the threshold value that would not affect the migration speed of CNT-tagged MSCs toward the established gradient of chemoattractant SDF-1α.

Enhanced Anticancer Activity of 5'-DFUR-PCL-MPEG Polymeric Prodrug Micelles Encapsulating Chemotherapeutic Drugs.

The compound 5'-deoxy-5-fluorouridine (5'-DFUR) is a prodrug of the anti-tumor drug 5-fluorouracil (5-FU). Thymidine phosphorylase (TP) is an enzyme that can convert 5'-DFUR to its active form 5-FU and the expression of TP is upregulated in various cancer cells. In this study, 5'-DFUR associated with amphiphilic copolymer poly(ε-caprolactone)-methoxy poly(ethylene glycol) (5'-DFUR-PCL-MPEG) was synthesized, characterized, and self-assembled into functional polymeric micelles. To demonstrate that the prodrug 5'-DFUR could convert into cytotoxic 5-fluorouracil (5-FU) by endogenous TP, HT-29 colorectal cancer cells were treated with 5'-DFUR-PCL-MPEG polymeric micelles for various time periods. Chemotherapeutic drugs doxorubicin (DOX) and 7-ethyl-10-hydroxycamptothecin (SN-38) were also encapsulated separately into 5'-DFUR-PCL-MPEG polymeric micelles to create a dual drug-loaded system. HT-29 cells were treated with DOX or SN-38 encapsulated 5'-DFUR-PCL-MPEG polymeric micelles to examine the efficacy of dual drug-loaded micelles. As a result, HT-29 cells treated with 5'-DFUR-PCL-MPEG polymeric micelles showed up to 40% cell death rate after a 72-h treatment. In contrast, HT-29 cells challenged with DOX or SN-38 encapsulated 5'-DFUR-incorporated polymeric micelles showed 36% and 31% in cell viability after a 72-h treatment, respectively.

Poly(N-isopropylacrylamide) modified polydopamine as a temperature-responsive surface for cultivation and harvest of mesenchymal stem cells.

A thermo-responsive surface was fabricated by depositing poly(N-isopropylacrylamide) (PNIPAAm) onto polydopamine coated cell culture substrata through free radical polymerization for the purpose of culturing and harvesting human mesenchymal stem cells (hMSCs). Human MSCs were cultured onto the PNIPAAm-g-polydopamine coated surface and harvested by changing from physiological to ambient temperature. The produced PNIPAAm-g-polydopamine surface was characterized by atomic force microscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance, water contact angle measurement, differential scanning calorimetry, and cell culture studies. Our results revealed that hMSCs could be detached from the PNIPAAm-g-polydopamine surface within 60 min after switching the temperature from 37 °C to room temperature. The detached hMSCs were able to proliferate on the PNIPAAm-g-polydopamine coated surface for further growth and harvest.

Antitumor therapy using nanomaterial-mediated thermolysis.

Nanomaterial-based systems present several novel therapeutic opportunities for cancer therapy based solely upon their unique physical and chemical properties. Despite advances in current cancer treatment, collateral damage to neighboring healthy tissues still cannot be avoided. By exploiting the strong optical and/or electromagnetic properties offered by nanomaterials, they are being employed as thermal nanoscalpels for the ablation of cancer cells. Through surface functionalization, these nanomaterials can be specifically targeted to tumorous tissue allowing for an increase in therapeutic potential and reduction in side effects. Moreover, these features provide nanomaterials with a tunable surface which can be used to modify optical, magnetic, thermal and mechanical properties. This review highlights carbon nanomaterials, nanogolds, magnetic nanoparticles and emerging hybrids applied for the thermolysis of cancer cells.

Engineering antiphagocytic biomimetic drug carriers.

Drug-delivery carriers have the potential to not only treat but also diagnose many diseases; however, they still lack the complexity of natural-particulate systems. Cell-based therapies using tumor-targeting T cells and tumor-homing mesenchymal stem cells have given researchers a means to exploit the characteristics exhibited by innate-biological entities. Similarly, immune evasion by pathogens has inspired the development of natural polymers to cloak drug carriers. The 'marker-of-self' CD47 protein, which is found ubiquitously on mammalian cell surfaces, has been used for evading phagocyte clearance of drug carriers. This review will focus on the recent progress of drug carriers co-opting the tricks that cells in nature use to hide safely under the radar of the body's innate immune system.

Gene transfection of Toxoplasma gondii using PEI/DNA polyplexes.

The purpose of this study was to explore the potential of using cationic polyethylenimine (PEI) to deliver green fluorescent protein (GFP) to protozoan parasite Toxoplasma gondii. PEI/DNA polyplexes were formed using branched PEI and pEGFP-N1 plasmid with various N/P ratios that ranged from 5 to 50. With the increment of N/P ratio, the average size of formed PEI/DNA polyplexes determined by dynamic light scattering analysis decreased from 306 to 203 nm, while the surface charge of polyplexes obtained by zeta potential measurements increased from 20.2 to 36.7 mV. Gene transfection efficiency modulated by N/P ratio was determined, indicating PEI/DNA polyplexes were capable of transfecting parasites. The maximal GFP expression was observed 8 h post-transfection using N/P ratio of 30. To demonstrate the infectivity and potential use of GFP-expressing T. gondii, transfected parasites were inoculated to the monolayer of human foreskin fibroblast (HFF) cells. GFP-expressing tachyzoites were observed in intracellular milieu of the infected HFF cells one day after the infection. After 12-day culture, the bradyzoites expressing GFP within cysts were clearly visualized extracellularly. Our results revealed that PEI can be harnessed as an effective and inexpensive reagent to construct GFP-expressing T. gondii which has potential uses such as the study of interconversion stages and antimicrobial drug screening.

Photothermolysis of glioblastoma stem-like cells targeted by carbon nanotubes conjugated with CD133 monoclonal antibody.

CD133(+) cells in glioblastoma (GBM) display cancer stem cell-like properties and have been considered as the culprit of tumor recurrence, justifying exploration of potential therapeutic modalities targeting CD133(+) cancer stem-like cells (CSCs). For photothermolysis studies, GBM-CD133(+) and GBM-CD133(-) cells mixed with various ratios were challenged with single-walled carbon nanotubes (SWNTs) conjugated with CD133 monoclonal antibody (anti-CD133) and then irradiated with near-infrared laser light. Results show that GBM-CD133(+) cells were selectively targeted and eradicated, whereas GBM-CD133(-) cells remained viable. In addition, in vitro tumorigenic and self-renewal capability of GBM-CD133(+) treated with localized hyperthermia was significantly blocked. Furthermore, GBM-CD133(+) cells pretreated with anti-CD133-SWNTs and irradiated by near-infrared laser 2 days after xenotransplantation in nude mice did not exhibit sustainability of CSC features for tumor growth. Taken altogether, our studies demonstrated that anti-CD133-SWNTs have the potential to be utilized as a thermal-coupling agent to effectively target and destroy GBM CSCs in vitro and in vivo. FROM THE CLINICAL EDITOR: Glioblastoma remains one of the most notorious cancer from the standpoint of recurrence and overall resistance to therapy. CD133+ stem cells occur among GBM cells, and may be responsible for the huge recurrence risk. This paper discusses a targeted elimination method of these cells, which may enable more efficient therapy in an effort to minimize or prevent recurrence.

Anti-Neuroblastoma Activity of Gold Nanorods Bound with GD2 Monoclonal Antibody under Near-Infrared Laser Irradiation.

High-risk neuroblastoma is one of the most common deaths in pediatric oncology. Current treatment of this disease involves a coordinated sequence of chemotherapy, surgery, and radiation. Further advances in therapy will require the targeting of tumor cells in a more selective and efficient way so that survival can be improved without substantially increasing toxicity. To achieve tumor-selective delivery, disialoganglioside (GD2) expressed by almost all neuroblastoma tumors represents a potential molecular target that can be exploited for tumor-selective delivery. In this study, GD2 monoclonal antibody (anti-GD2) was conjugated to gold nanorods (GNRs) which are one of anisotropic nanomaterials that can absorb near-infrared (NIR) laser light and convert it to energy for photothermolysis of tumor cells. Thiolated chitosan, due to its biocompatibility, was used to replace cetyltrimethylammonium bromide (CTAB) originally used in the synthesis of gold nanorods. In order to specifically target GD2 overexpressed on the surface of neuroblastoma stNB-V1 cells, anti-GD2 was conjugated to chitosan modified GNRs (CGNRs). To examine the fate of CGNRs conjugated with anti-GD2 after incubation with neuroblastoma cells, rhadoamine B was labeled on CGNRs functionalized with anti-GD2. Our results illustrated that anti-GD2-conjugated CGNRs were extensively endocytosed by GD2+ stNB-V1 neuroblastoma cells via antibody-mediated endocytosis. In addition, we showed that anti-GD2 bound CGNRs were not internalized by GD2- SH-SY5Y neuroblastoma cells. After anti-GD2-linked CGNRs were incubated with neuroblatoma cells for six hours, the treated cells were further irradiated with 808 nm NIR laser. Post-NIR laser exposure, when examined by calcein-AM dye, stNB-V1 cells all underwent necrosis, while non-GD2 expressing SH-SY5Y cells all remained viable. Based on the in vitro study, CGNRs bound with anti-GD2 has the potential to be utilized as a therapeutic thermal coupling agent that generates heat sufficient to selectively kill neuroblastoma cells under NIR laser light exposure.

Anticancer effectiveness of polymeric drug nanocarriers on colorectal cancer cells.

Doxifluridine, a prodrug of 5-fluorouracil (5-FU), was used as the initiator directly in ring-opening polymerization of ε-caprolactone to form hydrophobic doxifluridine-poly(ε-caprolactone) (doxifluridine-PCL) that was further grafted with hydrophilic chitosan to synthsize amphiphilic doxifluridine-PCL-chitosan copolymer. This amphiphilic copolymer was self-assembled into micellar nanoparticles. After HT-29 colon cancer cells were treated with the polymeric drug nanocarrier, prodrug doxifluridine was converted into 5-fluorouracil by endogenous thymidine phosphorylase (TP) and thereby resulting in cell death. Chemotherapy drug 7-ethyl-10-hydroxy-camptothecin (SN-38), an active water insoluble metabolite of irinoetcan hydrochloride, was further encapsulated in the hydrophobic core of the polymeric drug nanocarriers and treated with HT-29 cells. The anticancer effectiveness of the polymeric drug nanocarriers was extensively enhanced by synergistic anticancer activity of slowly released cytotoxic drugs (i.e., 5-FU and SN-38). HT-29 cells transfected with TP-encoding plasmids were selected by antibiotic G418 to obtain HT-29/TP cells. These cells overexpressed with TP enzyme were challenged with doxifluridine-PCL-chitosan polymeric prodrug micelles. The viability of HT-29/TP cells were dropped significantly after 72-h treatment.