New distribution of Reticulitermes speratus speratus (Blattodea: Rhinotermitidae) in Korea.

Reticulitermes speratus (Kolbe) is economically important pest in East Asia including Korea, Japan, and China where they infest wooden structures in urban areas. Previously, it has been reported that R. speratus consists of 5 subspecies, R. speratus kyushuensis Morimoto, R. speratus speratus Kolbe, R. speratus leptolabralis Morimoto, R. speratus okinawanus Morimoto, R. speratus yaeyamanus Morimoto, while only R. speratus kyushuensis was recorded in Korea in the past. However, it remains elusive if different subspecies of R. speratus other than R. speratus kyushuensis are present in Korea. In this study, we report the first record of R. speratus speratus from Korea, which was verified using soldier morphology and molecular characteristics obtained from a mitochondrial gene. R. speratus speratus Kolbe, 1885 (Blattodea: Rhinotermitidae) are found in several provinces, mainly southern regions in Korea, whereas R. speratus kyushuensis are distributed throughout the country. Our morphological comparison showed that R. speratus speratus can be distinguishable from R. speratus kyushuensis by the ratio of the posterior postmentum width to length. In the molecular comparison, R. speratus speratus revealed genetic differences of 3.06% (range 2.60-4.10%) from R. speratus kyushuensis using cytochrome oxidase subunit II gene sequences.

A comparison of tunnel geometry between the Formosan subterranean termite and the Asian subterranean termite (Blattodea: Rhinotermitidae).

BACKGROUND: Stake surveys and in-ground monitoring stations have been widely used to study field populations of many subterranean termite species, but thus far they have never been intercepted by the invasive Asian subterranean termite, Coptotermes gestroi (Wasmann), in southeastern Florida. To investigate the reasons for the inability of C. gestroi to intercept these in-ground monitoring devices, we compared its tunnel geometry with that of the Formosan subterranean termite, Coptotermes formosanus Shiraki. Two-year-old incipient colonies of both species confined in simulated structural infestations were connected to planar arenas containing four wooden discs. RESULTS: Coptotermes formosanus colonies constructed more abundant and more complex tunnel networks and intercepted more wooden discs than C. gestroi. C. formosanus propagated shorter primary tunnels and longer secondary tunnels with more branching frequency than C. gestroi, and probably adopted an area searching strategy to search for food in an area before moving on to other areas. In comparison, C. gestroi used a distance searching strategy by constructing linear and long primary tunnels to search for food at distance. CONCLUSIONS: Because tunnels of C. gestroi were less abundant and they tend to travel straight for some distance, they may have bypassed survey stakes or in-ground monitoring stations that are sparsely distributed in soil. The tunnel geometry of C. gestroi may explain why none of these in-ground monitoring devices has been intercepted by this species in southeastern Florida. © 2023 Society of Chemical Industry.

Exuviae Recycling Can Enhance Queen Oviposition and Colony Growth in Subterranean Termites (Blattodea: Rhinotermitidae: Coptotermes).

Wood-feeding termites have a nitrogen-poor diet and have therefore evolved nitrogen conservation strategies. However, termite workers molt periodically, and throughout the lifetime of a colony, millions of exuviae, a nitrogen-rich resource, are produced by the colony. In Coptotermes Wasmann, workers foraging at remote feeding sites must return to the central part of the nest to molt, where the queen, king, eggs, and larvae are located. It was hypothesized that this molting-site fidelity is an efficient way to recycle nitrogen for reproduction and colony growth, as nestmates involved in exuviae consumption can directly transfer such resources to individuals engaged in reproduction (the queen) or growth (larvae). This study investigates whether incipient colonies of C. gestroi (Wasmann) can gain additional biomass when they are fed supplementary exuviae. Incipient colonies were reared in nitrogen-poor or nitrogen-rich conditions, and 0, 1, 5, or 10 exuviae were added to 3-month-old colonies. After 6.5 months, colonies reared in nitrogen-poor environments gained significantly more biomass when exuviae were added than colonies with no added exuviae. However, the addition of exuviae had no effect on colony growth for colonies reared in nitrogen-rich environments. In a second experiment, queens from colonies in which exuviae were effectively removed laid fewer eggs than queens from colonies in which exuviae were not removed. Therefore, consumption of exuviae from molting individuals by nestmates is an important part of the nitrogen recycling strategy in Coptotermes colonies, as it facilitates queen oviposition and colony growth, especially when such colonies have limited access to nitrogen-rich soils.

Sinapic Acid Attenuates the Neuroinflammatory Response by Targeting AKT and MAPK in LPS-Activated Microglial Models.

Sinapic acid (SA) is a phenolic acid that is widely distributed in fruits and vegetables, which has various bioactivities, such as antidiabetic, anticancer and anti-inflammatory functions. Over-activated microglial is involved in the development progress of neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease. The objective of this study was to investigate the effect of SA in microglia neuroinflammation models. Our results demonstrated that SA inhibited secretion of the nitric oxide (NO) and interleukin (IL)-6, reduced the expression of inducible nitric oxide synthase (iNOS) and enhanced the release of IL-10 in a dose-dependent manner. Besides, our further investigation revealed that SA attenuated the phosphorylation of AKT and MAPK cascades in LPS-induced microglia. Consistently, oral administration of SA in mouse regulated the production of inflammation-related cytokines and also suppressed the phosphorylation of MAPK cascades and AKT in the mouse cerebral cortex. These results suggested that SA may be a possible therapy candidate for anti-inflammatory activity by targeting the AKT/MAPK signaling pathway.

Inferring Termite Colony Size Using Wood Consumption in Subterranean Termites (Blattodea: Rhinotermitidae) in Laboratory-Rearing Conditions.

Termite colony size can influence its foraging activity, reproductive maturity, and, for pest species, potential for structural damage. Estimating colony size of subterranean termite species in field conditions has been challenging owing to their extensive foraging territory and their cryptic nesting habit and has primarily relied on mark-recapture methods. With laboratory-reared colonies in individual containers, determining colony size can be achieved by processing all termites from the nest material, which can be labor intensive and partially destructive. However, with the recent rise in the need of large laboratory colonies for use in colony-wide experimental protocols, there was an imperative to develop a procedure to estimate initial colony sizes without imposing a major stress on colonies before an experiment. In this study, the average daily wood consumption of whole colonies was used to infer the colony size of two Coptotermes, Wasmann (Blattodea: Rhinotermitidae) species and their hybrids in laboratory-rearing conditions. Correlations between the daily wood consumption and several demographic variables within colonies were established. Linear models varied across all species mating types with R2 values greater than 0.8 for all demographic variables. For colonies from all mating combinations, Pearson's correlation coefficient values were greater than 0.94 between their daily wood consumption and both the number of workers and total number of termites, and greater than 0.91 between daily wood consumption and colony mass. Therefore, in colonies with fixed laboratory conditions, their average daily wood consumption determination, which is nondestructive on colonies, can be used to infer colony size of subterranean termites.

A Reproductives Excluder for Subterranean Termites in Laboratory Experiments.

As a social insect, termites have different castes and division of labor in a colony. Investigating the social behavior of subterranean termites is a challenge due to the cryptic nature and large colony size. Planar arenas are commonly used to study these termites under laboratory conditions, and have provided several advantages. However, there is no means to designate areas such as a royal chamber or central nest from foraging sites because reproductives can move freely across arenas. In this study, we examined the minimum passing size of different castes of Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), in order to develop a reproductive excluder and correlated minimum passing size with head widths and heights. We found that workers and soldiers of C. formosanus were able to pass through a gap greater than or equal to 0.7 mm. Our results showed that there are significant differences in the head width and height based on castes and head height was more critical than head width to determine passing size. We further confirmed feasibilities of the reproductive excluders using incipient colonies of C. formosanus. Confining reproductives using the excluder in laboratory experiments will provide more chances to study the royal chamber and central nest independently of foraging sites.

Neuroprotective effect of anodal transcranial direct current stimulation on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in mice through modulating mitochondrial dynamics.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the accumulation of protein inclusions and the loss of dopaminergic neurons. Abnormal mitochondrial homeostasis is thought to be important for the pathogenesis of PD. Transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique, constitutes a promising approach for promoting recovery of various neurological conditions. However, little is known about its mechanism of action. The present study elucidated the neuroprotective effects of tDCS on the mitochondrial quality control pathway in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model. We used the MPTP-induced neurotoxicity in vivo model. Mice were stimulated for 5 consecutive days with MPTP treatment. After observation of behavioral alteration using the rotarod test, mice were sacrificed for the measurement of the PD- and mitochondrial quality control-related protein levels in the substantia nigra. tDCS improved the behavioral alterations and changes in tyrosine hydroxylase levels in MPTP-treated mice. Furthermore, tDCS attenuated mitochondrial damage, as indicated by diminished mitochondrial swelling and mitochondrial glutamate dehydrogenase activity in the MPTP-induced PD mouse model. MPTP significantly increased mitophagy and decreased mitochondrial biogenesis-related proteins. These changes were attenuated by tDCS. Furthermore, MPTP significantly increased fission-related protein dynamin-related protein 1 with no effect on fusion-related protein mitofusin-2, and tDCS attenuated these changes. Our findings demonstrated the neuroprotective effect of anodal tDCS on the MPTP-induced neurotoxic mouse model through suppressing excessive mitophagy and balancing mitochondrial dynamics. The neuroprotective effect of anodal tDCS with modulation of mitochondrial dynamics provides a new therapeutic strategy for the treatment of PD.

Fused Colonies of the Formosan Subterranean Termite (Blattodea: Rhinotermitidae) for Laboratory Experiments.

Laboratory studies of Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae) often employ the use of field-collected foraging populations of individuals as defined colonies. The biological relevance of this practice is often called into question, because these colonies lack a full composition of reproductive castes and brood, which may have physiological and behavioral consequences. Rearing intact laboratory colonies can be done; however, it is time-consuming and labor-intensive. The artificial fusion of field-collected foraging populations with a young, laboratory-reared incipient colony may provide whole, intact colonies for laboratory research. The current study measures survivorship of fused colonies using laboratory-reared complete incipient colonies ranging in age from 0 to 5 mo, fused with 100 workers and 10 soldiers from field-collected populations of different colonial origin. Results indicate that 60% of colony fusion was successful when the incipient colony introduced is 5 mo of age. This method of colony fusion will provide researchers with intact colonies using minimal resources.

Staphylococcus aureus-mimetic control of antibody orientation on nanoparticles.

We designed a bacterio-mimetic nanoparticle that can noncovalently control the orientation of attached antibodies. Liposomes with Fc-binding peptide (FcBP), formulated using FcBP-conjugated PEGylated lipid, were used as model nanoparticles. Compared with control nanoparticles surface-modified with antibody covalently attached via maleimide functional groups (Mal-NPs), FcBP-capped nanoparticles (FcBP-NPs) exhibited greater binding affinity to the target protein. Human epidermal growth factor receptor 2 (HER2)-specific antibody-modified FcBP-NPs (HER2/FcBP-NPs) showed 5.3-fold higher binding affinity to HER2 than isotype IgG antibody-modified NPs, and 2.6-fold higher affinity compared with anti-HER2 antibody-conjugated Mal-NPs. Cellular uptake of HER2/FcBP-NPs in HER2-positive cells was significantly higher than that of other formulations. The biodistribution of HER2/FcBP-NPs was higher than that of antibody-conjugated NPs in HER2-positive tumor tissues, but not in HER2-negative tumors. Our findings suggest the potential of bacteriomimetic nanoparticles for controlling the orientation of antibody attachment. These nanoparticles may have diverse applications in nanomedicine, including drug delivery, molecular imaging, and diagnosis.

Lower expression of tumor microRNA-26a is associated with higher recurrence in patients with hepatocellular carcinoma undergoing surgical treatment.

BACKGROUND AND OBJECTIVES: Hepatocellular carcinoma (HCC) in patients with hepatitis B virus (HBV) exhibit lower tumor microRNA-26a (miR-26a) expression which is associated with worse outcomes. It is unknown if similar miR-26a loss occurs in HCC developed in other liver diseases. We examined tumor miR-26a expression and its impact on recurrence and mortality in a North American HCC cohort. METHODS: MiR-26a levels from tumor and surrounding nontumor liver tissue in 186 subjects were collected. We defined lower tumor expression of miR-26a as <1-fold that of the adjacent nontumor liver tissue. RESULTS: Viral hepatitis (42%; 40% hepatitis C and 2% HBV), alcohol (19%), and nonalcoholic fatty liver disease (NAFLD) (18%) were the most common causes of liver disease. The prevalence of lower tumor miR-26a expression was 68%, and it was evident in HCCs arising in all etiologies (viral hepatitis 60%, alcohol 61%, and NAFLD 76%). Subjects with lower tumor miR-26a expression had significantly higher tumor recurrence (hazard ratio [HR], 2.45; 95% confidence interval [CI], 1.18 to 5.1; P = 0.016) and higher mortality of borderline significance (HR, 1.51; 95% CI, 0.94 to 2.41; P = 0.086). CONCLUSION: Reduced miR-26a expression is a common phenomenon in HCC arising in North American patients with different underlying liver diseases and may increase recurrence and mortality after surgery.

Wild ginseng cambial meristematic cells ameliorate hepatic steatosis and mitochondrial dysfunction in high-fat diet-fed mice.

OBJECTIVES: The aim of this study was to determine the protective mechanisms of wild ginseng cambial meristematic cells (CMCs) on non-alcoholic fatty liver disease in high-fat diet (HFD)-fed mice. METHODS: Male C57BL/6 mice received either normal-fat diet or HFD for 10 weeks along with wild ginseng CMCs (75, 150 and 300 mg/kg) or vehicle (0.5% carboxyl methyl cellulose) by oral administration once a day. Triglyceride and total cholesterol contents were measured in liver and serum samples. Parameters for hepatic lipid metabolism and mitochondria biogenesis were assessed. KEY FINDINGS: Treatment with wild ginseng CMCs markedly attenuated body weight, serum and hepatic lipid contents, and serum aminotransferase activity. While wild ginseng CMCs attenuated the increases in sterol regulatory element-binding transcription factor 1 (SREBP-1) and carbohydrate-responsive element-binding protein (ChREBP) expression, it enhanced the increases in carnitine palmitoyltransferase 1A (CPT1A) and peroxisome proliferator-activated receptor alpha (PPAR-α) expression. HFD decreased glutamate dehydrogenase activity and glutathione content, and increased lipid peroxidation, which were all attenuated by wild ginseng CMCs. Furthermore, wild ginseng CMCs enhanced mitochondrial biogenesis-related factors, including peroxisome proliferator-activated receptor-γ co activator 1α (PGC1α), nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM). CONCLUSIONS: Wild ginseng CMCs protect against HFD-induced liver injury, which prevents lipid accumulation and mitochondrial oxidative stress, and enhances mitochondrial biogenesis.

Pharmacokinetics and in vivo fate of intra-articularly transplanted human bone marrow-derived clonal mesenchymal stem cells.

In this study, we report the pharmacokinetics and in vivo fate of intra-articularly transplanted human mesenchymal stem cells (MSCs) in comparison with those of intravenously administered cells. Bone marrow-derived human clonal mesenchymal stem cells (hcMSCs) were transplanted to nude mice through intravenous or intra-articular routes. The numbers of hcMSCs in blood and tissue samples were measured by the quantitative real-time-polymerase chain reaction (qPCR) with human Alu (hAlu) as a detection marker. Following intra-articular transplantation, the blood levels of hcMSCs peaked 8 h postdose and gradually diminished, showing a 95-fold higher mean residence time than hcMSCs delivered through the intravenous route. Unlike intravenously administered hcMSCs, intra-articularly injected hcMSCs were mainly retained at injection joint sites where their levels 8 h postdose were 116-fold higher than those in muscle tissues. Regardless of injection routes, biodistribution patterns did not significantly differ between normal and osteoarthritis-induced mice. Quantitative analysis using hAlu-specific qPCR revealed that hcMSC levels in joint tissues were significantly higher than those in muscle tissues 120 days postdose. These dramatic differences in kinetic behavior and fate of intra-articularly transplanted hcMSCs compared with intravenously administered hcMSCs may provide insights useful for the development of human MSCs for arthritis therapeutics.

Liposomal co-delivery of omacetaxine mepesuccinate and doxorubicin for synergistic potentiation of antitumor activity.

PURPOSE: Anticancer chemotherapy usually involves the administration of several anticancer drugs that differ in their action mechanisms. Here, we aimed to test whether the combination of omacetaxine mepesuccinate (OMT) and doxorubicin (DOX) could show synergism, and whether the liposomal co-delivery of these two drugs could enhance their antitumor effects in cervical carcinoma model. METHOD: OMT-loaded liposomes (OL) were prepared by loading the drug in the lipid bilayers. OL were then electrostatically complexed with DOX, yielding double-loaded liposomes (DOL). DOX-loaded liposomes (DL) were formulated by electrostatic interaction with negatively charged empty liposomes (EL). The combination index (CI) values were calculated to evaluate the synergism of two drugs. In vitro antitumor effects against HeLa cells were measured using CCK-8, calcein staining, and crystal violet staining. In vivo antitumor effects of various liposomes were tested using HeLa cell-bearing mice. RESULTS: Combination of DOX and OMT had ratio-dependent synergistic activities, with very strong synergism observed at a molar ratio of 4:1 (DOX:OMT). The sizes of EL, DL, OL, and DOL did not significantly differ, but the zeta potentials of DL and DOL were slightly higher than those of OL and EL. In vitro, DOL showed higher antitumor activity than OL, DL or EL in cervical carcinoma HeLa cells. In vivo, unlike other liposomes, DOL reduced the tumor growths by 98.6% and 97.3% relative to the untreated control on day 15 and 25 after the cessation of treatment, respectively. CONCLUSIONS: These results suggest that liposomal co-delivery of DOX and OMT could synergistically potentiate antitumor effects.

64Cu-Labeled tetraiodothyroacetic acid-conjugated liposomes for PET imaging of tumor angiogenesis.

INTRODUCTION: We synthesized and evaluated (64)Cu-labeled tetraiodothyroacetic acid (tetrac)-conjugated liposomes for PET imaging of tumor angiogenesis, because tetrac inhibits angiogenesis via integrin αVß3. METHODS: Tetrac-PEG-DSPE and DOTA-PEG-DSPE were synthesized and formulated with other lipids into liposomes. The resulting tetrac/DOTA-liposomes were labeled with (64)Cu at 40 °C for 1 h and purified using a PD-10 column. (64)Cu-DOTA-liposomes were also prepared for comparison. Human aortic endothelial cell (HAEC) binding studies were performed by incubating the liposomes with the cells at 37 °C. MicroPET imaging followed by tissue distribution study was carried out using U87MG tumor-bearing mice injected with tetrac/(64)Cu-DOTA-liposomes or (64)Cu-DOTA-liposomes. RESULTS: HAEC binding studies exhibited that tetrac/(64)Cu-DOTA-liposomes were avidly taken up by the cells from 1.02 %ID at 1 h to 11.89 %ID at 24 h, while (64)Cu-DOTA-liposomes had low uptake from 0.47 %ID at 1 h to 1.57 %ID at 24 h. MicroPET imaging of mice injected with tetrac/(64)Cu-DOTA-liposomes showed high radioactivity accumulation in the liver and spleen. ROI analysis of the tumor images revealed 1.93 ± 0.12 %ID/g at 1 h and 2.70 ± 0.36 %ID/g at 22 h. In contrast, tumor ROI analysis of (64)Cu-DOTA-liposomes revealed 0.54 ± 0.08 %ID/g at 1 h and 0.52 ± 0.09 %ID/g at 22 h. Tissue distribution studies confirmed that the tumor uptakes of tetrac/(64)Cu-DOTA-liposomes and (64)Cu-DOTA-liposomes were 1.75 ± 0.03 %ID/g and 0.36 ± 0.01 %ID/g at 22 h, respectively. CONCLUSION: These results demonstrate that tetrac/(64)Cu-DOTA-liposomes have significantly enhanced tumor uptake compared to (64)Cu-DOTA-liposomes due to tetrac conjugation. Further studies are warranted to reduce the liver and spleen uptake of tetrac/(64)Cu-DOTA-liposomes.

Enhanced survival of transplanted human adipose-derived stem cells by co-delivery with liposomal apoptosome inhibitor in fibrin gel matrix.

To improve the survival of transplanted human adipose-derived stem cells (ADSCs), a liposome preparation containing the apoptosome inhibitor, NS3694, was formulated and co-delivered with ADSCs in fibrin gel scaffolds. Liposomes provided enhanced effect on ADSC proliferation in vitro as compared to free drug. Exposure of ADSCs to liposomal NS3694 for 7 days did not affect the surface marker expression profile. NS3694 encapsulated in negatively charged liposomes composed of phosphatidylcholine, phosphatidylglycerol, and cholesterol was evaluated in vivo following subcutaneous transplantation in mice. Survival of ADSCs co-delivered with liposomal NS3694 was significantly higher than that of untreated ADSCs or ADSCs treated with free NS3694 or empty liposomes. An immunohistochemical analysis revealed a higher number of human nucleus-positive cells after treatment with liposomal NS3694 than following treatment with free NS3694. Similarly, liposomal NS3694 significantly enhanced survival of transplanted ADSCs in rabbits compared to other treatments. Taken together, our results indicate the potential of liposomal NS3694 co-delivered with ADSCs using fibrin gel systems as an in vivo-survival enhancer.

Enhanced intrapulmonary delivery of anticancer siRNA for lung cancer therapy using cationic ethylphosphocholine-based nanolipoplexes.

Here, we report a cationic nanolipoplex as a pulmonary cellular delivery system for small-interfering RNA (siRNA). Six nanoliposomes differing in cationic lipids were formulated and screened in vitro and in vivo for cellular delivery functions in lung cells/tissues. Although the six nanoliposomes showed similar siRNA delivery efficiency in vitro, they exhibited significant differences in pulmonary cellular delivery functions in vivo. Among the various nanoliposomes, cationic dioleoyl-sn-glycero-3-ethylphosphocholine and cholesterol (ECL)-based nanoliposomes showed the highest pulmonary cellular delivery in vivo and the lowest cytotoxicity in vitro. The delivery efficiency of fluorescent siRNA in ECL nanoliposomes was 26.2-fold higher than that of naked siRNA in vivo. Treatment with Mcl1 (myeloid cell leukemia sequence 1)-specific siRNA (siMcl1) using ECL nanolipoplexes reduced target expression in B16F10 cell lines, whereas control, luciferase-specific siGL2 in ECL nanolipoplexes did not. In metastatic lung cancer mouse models induced by B16F10 or Lewis lung carcinoma (LLC) cells, intratracheal administration of siMcl1 in ECL nanolipoplexes significantly silenced Mcl1 mRNA and protein levels in lung tissue. Reduced formation of melanoma tumor nodules was observed in the lung. These results demonstrate the utility of ECL nanoliposomes for pulmonary delivery of therapeutic siRNA for the treatment of lung cancers and potentially for other respiratory diseases.

Safety and tumor tissue accumulation of pegylated graphene oxide nanosheets for co-delivery of anticancer drug and photosensitizer.

Here, we report the safety, tumor accumulation and potential of polyethylene glycol-grafted graphene oxide (pGO) as a multimodal nanocarrier of photosensitizers and synergistic anticancer agents. First, both graphene oxide (GO) and pGO were synthesized, and their in vitro and in vivo toxicities were tested. When 80 mg/kg was injected intravenously into mice, there was 100% fatality in the GO-treated group, but 100% survival among mice treated with pGO nanosheets. Treatment of cells with a photosensitizer chlorin e6 (Ce6) in pGO nanophysisorplexes significantly enhanced cellular delivery compared to that seen with Ce6 alone. The combination and dose reduction indexes revealed that combining doxorubicin (Dox) with Ce6 with at a molar ratio of 1:2 provided the highest synergism. The Ce6- and Dox-loaded pGO nanophysisorplexes (Ce6/Dox/pGO) were 148.0 ± 18.0 nm in size. Molecular imaging of mice showed that Ce6/Dox/pGO could accumulate in tumor tissues over 3 days. Moreover, in SCC tumor-bearing mice, the photodynamic anticancer effects of Ce6/Dox/pGO were higher than those of Ce6/pGO or Dox/pGO. Moreover, tumor sections from illuminated mice treated with Ce6/Dox/pGO showed substantial disruption of tumor nuclei, whereas the other groups did not. Our results suggest that pGO nanosheets have superior in vivo safety relative to GO, and that it is possible to enhance the tumor tissue distribution and photodynamic anticancer effects of systemically administered Ce6 by forming multimodal nanophysisorplexes with pGO and synergistic anticancer chemotherapeutics such as Dox.

Tetraiodothyroacetic acid-tagged liposomes for enhanced delivery of anticancer drug to tumor tissue via integrin receptor.

Nanoparticles have demonstrated potential for promoting drug delivery to tumor sites and enhancing uptake. Here, we report tetraiodothyroacetic acid (tetrac) as a promising new targeting moiety for delivery of anticancer drugs to tumor tissues. Tetrac, an antagonist that blocks the binding of thyroid hormone to integrin αvß3, was covalently linked to the activated end of pegylated lipid and used to formulate tetrac-tagged pegylated liposomes (TPL). After incubating with TPL for 9h, cellular accumulation efficiency into A375 human melanoma cells, which express integrin αvß3 at high density, was high (98.5%± 0.5% of cells), whereas that in KB cells, which express integrin at a very low density, was much lower (35.1%± 4.5%). Molecular imaging revealed that TPL preferentially distributed to tumor tissues after systemic administration in mice, where as non-targeting pegylated liposomes were distributed to tumors at background levels. Treatment with the alkyl lysophospholipid anticancer drug edelfosine, encapsulated in TPL, significantly reduced the survival of A375 tumor cells compared to cells treated with edelfosine in pegylated liposomes or with lysophosphatidylcholine encapsulated in TPL. Moreover, intravenous administration of edelfosine in TPL significantly reduced the growth of tumors and prolonged the survival of A375-xenografted mice, providing 100% protection for up to 50 days and some protection until 66 days (0% survival endpoint). In contrast, no untreated mice or mice treated with edelfosine-loaded pegylated liposomes survived up to 50 or 48 days, respectively, after tumor inoculation. These results suggest the potential of tetrac as a new ligand moiety for enhancing the delivery of anticancer drug-loaded nanoparticles to tumors and enhancing the therapeutic efficacy of encapsulated anticancer drugs.

Cationic solid lipid nanoparticles for co-delivery of paclitaxel and siRNA.

In this study, we formulated cationic solid lipid nanoparticles (cSLN) for co-delivery of paclitaxel (PTX) and siRNA. 1,2-Dioleoyl-sn-glycero-3-ethylphosphocholine-based cSLN were prepared by emulsification solidification methods. PTX-loaded cSLN (PcSLN) were characterized by zeta potential and gel retardation of complexes with small interfering RNA (siRNA). The sizes of PcSLN did not significantly differ from those of empty cSLN without PTX (EcSLN). The use of cSLN increased the cellular uptake of fluorescent dsRNA in human epithelial carcinoma KB cells, with PcSLN complexed to fluorescence-labeled dsRNA promoting the greatest uptake. For co-delivery of therapeutic siRNA, human MCL1-specific siRNA (siMCL1) was complexed with PcSLN; luciferase-specific siRNA (siGL2) complexed to EcSLN or PcSLN was used as a control. MCL1 mRNA levels were significantly reduced in KB cells treated with siMCL1 complexed to PcSLN, but not in groups treated with siMCL alone or siGL2 complexed to PcSLN. siMCL1 complexed to PcSLN exerted the greatest in vitro anticancer effects in KB cells, followed by siMCL1 complexed to EcSLN, siGL2 complexed to PcSLN, PTX alone, and siMCL1 alone. In KB cell-xenografted mice, intratumoral injection of PcSLN complexed to siMCL1 significantly reduced the growth of tumors. Taken together, our results demonstrate the potential of cSLN for the development of co-delivery systems of various lipophilic anticancer drugs and therapeutic siRNAs.

Cationic drug-derived nanoparticles for multifunctional delivery of anticancer siRNA.

Combined treatment of anticancer drugs and small interfering RNAs (siRNAs) have emerged as a new modality of anticancer therapy. Here, we describe a co-delivery system of anticancer drugs and siRNA in which anticancer drug-derived lipids form cationic nanoparticles for siRNA complexation. The anticancer drug mitoxantrone (MTO) was conjugated to palmitoleic acid, generating two types of palmitoleyl MTO (Pal-MTO) lipids: monopalmitoleyl MTO (mono-Pal-MTO) and dipalmitoleyl MTO (di-Pal-MTO). Among various lipid compositions of MTO, nanoparticles containing mono-Pal-MTO and di-Pal-MTO at a molar ratio of 1:1 (md11-Pal-MTO nanoparticles) showed the most efficient cellular delivery of siRNA, higher than that of Lipofectamine 2000. Delivery of red fluorescence protein-specific siRNA into B16F10-RFP cells using md11-Pal-MTO nanoparticles reduced the expression of RFP at both mRNA and protein levels, demonstrating silencing of the siRNA target gene. Moreover, delivery of Mcl-1-specific anticancer siRNA (siMcl-1) using md11-Pal-MTO enhanced antitumor activity in vitro, reducing tumor cell viability by 81% compared to a reduction of 68% following Lipofectamine 2000-mediated transfection of siMcl-1. Intratumoral administration of siMcl-1 using md11-Pal-MTO nanoparticles significantly inhibited tumor growth, reducing tumor size by 83% compared to untreated controls. Our results suggest the potential of md11-Pal-MTO multifunctional nanoparticles for co-delivery of anticancer siRNAs for effective combination therapy.