Expression is higher among primary tumors and metastases than effusions, and effusions show complete cytoplasmic localization of Snail1 [133]. Snail1 represses E-cadherin and upregulates MMPs, and E-cadherin expression correlates with disease-free survival while MMP-2 is considered

a PR-171 nmr marker of poor prognosis [129]. Gastric carcinoma E-cadherin expression is drastically reduced in gastric carcinoma, JNK inhibitor mouse and Snail1 expression levels once again share an inverse relationship with E-cadherin expression levels [129]. Snail1 expression levels are more comparable to breast than ovarian carcinomas, and Snail1 expression is still higher in diffuse rather than intestinal varieties of gastric carcinomas [129,134]. Elevated Snail1 expression increases cells’ capacities for

migration and invasion. Overexpression correlates with tumor size, depth of invasion, and lymph node metastasis. Shortened survival rates are also directly related to Snail1 overexpression, and Snail1 is considered a predictor of poor prognosis [135]. Oral squamous carcinoma Oral squamous carcinoma Selleckchem OSI 906 is another case of E-cadherin/Snail1 expression inversion, and the higher the Snail1 expression, the more invasive the cancer. E-cadherin positive cells maintain their cuboidal shape while E-cadherin negative cells turn spindle-shaped. This is a typical sign of EMT, and it shows Snail1’s repression of E-cadherin [136]. Pancreatic carcinoma Pancreatic carcinoma tissues show significantly reduced E-cadherin levels and relatively high Snail1 expression [129]. In one study, 78% (n = 36) of ductal adenocarcinoma tissues expressed Snail1, and Snail1 expression is higher in undifferentiated cell lines than in differentiated ones [137]. Colorectal carcinoma Colorectal cancer (CRC) begins in gland cells that line the colon and rectum, and it is one of the most commonly newly diagnosed cancers and a leading cause of cancer-related deaths [138]. Snail1 expression is again inversely correlated to click here E-cadherin expression in CRC, and the expression

level of Snail1 is quite high in CRC (78%, n = 59) [130,139]. Interestingly, the mean age of the Snail1-positive group was nine years older than the Snail1-negative group in one study, with a standard deviation of 12.7 years (58.9 years vs. 49.8 years, n = 59) [139]. In another study, Snail1 expression was detected by Western blot in all tested CRC lines, and its expression increased both migratory and invasive properties. Additionally, Snail1 expression led to a stem-cell like phenotype and spindle shape, as usually accompanies the loss of E-cadherin [140]. Snail1 expression also increased with the stage of the tumors, with 15/23 stage III expressing Snail1 and 6/6 of stage IV. The significantly higher rate of metastasis associated with Snail1 expression suggests that Snail1’s presence indicates a high risk of distant metastases [139,140].

S2). This early induction is not surprising, as this enzyme performs a preliminary step in common pathways that include isoprenoid and ergosterol synthesis. In carotenogenesis, it is the second essential enzyme of the mevalonate pathway, after 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR), which catalyzes the phosphorylation of mevalonic acid to produce phosphomevalonate. MK activity is regulated by intermediates in the pathway, such as geranyl pyrophosphate, FPP and GGPP, via feedback inhibition [47]. For phosphomevalonate

kinase we observed the highest abundance at lag phase, while diphosphomevalonate decarboxylase reached its highest levels during the exponential and stationary phases. Because these two proteins perform sequential ARS-1620 order steps in the transformation of mevalonate our results indicate that this pathway is tightly regulated to ensure metabolite EX 527 concentration availability. Another significant carotenoid-synthesis protein is phytoene/squalene synthase, which showed higher abundance at the end of the exponential growth during the induction of carotenoid synthesis (Table 1 and additional file 4, Fig. S2). This result agrees with our previously reported mRNA expression analysis, in which the maximal levels of carotenoid-specific genes were observed after three days of culture, at the end

of the exponential growth phase [22, 23]. In constrast, in H.

pluvialis, the mRNA transcript levels of carotenoid-related genes reach their maximal levels 24-48 h after stress induction, and the synthesis and accumulation of astaxanthin occur 6-12 days after stress [48]. Another enzyme that performs an initial step in carotenogenesis, isopentenyl-diphosphate isomerase (IDI), shows maximum expression at 24 h after stress induction in H. pluvialis, and is then down-regulated as stress persist; a similar behavior has also been observed for phytoene desaturase [43, 49] (see additional file 3, Table S2). Thus, carotenoid-related enzymes in both H. pluvialis and X. dendrorhous may have low turnover rates; Non-specific serine/threonine protein kinase this low rate ensures their long-term activities in astaxanthin biosynthesis. Conclusions In this work, which is the first proteomic characterization of X. dendrorhous, we describe a protocol for the enrichment of protein extracts for membrane-bound proteins and the efficient extraction of proteins in the presence of excess hydrophobic materials such as lipids or carotenoids. We have also generated a preliminary proteome map, which will be valuable for further studies of the organism under different growth conditions. We Angiogenesis inhibitor identified two principal types of protein regulation associated with astaxanthin biosynthesis.

This is necessary

because the amount of oleic acid affects MNC formation. Steric repulsion among the hydrocarbon tails of oleic acid on individual MNPs impacts assembly capability of individual MNPs. To modify the amount of oleic acid on the MNPs, the MNPs were dissolved in n-hexane IACS-10759 in vivo and ethanol was added to the solution to remove part of the oleic acid coating. Finally, three samples of PMNPs were successfully obtained from the precipitates [25, 26], each coated with different oleic acid amounts: 19 (low PMNPs, LMNPs), 33 (medium PMNPs, MMNPs), and 46 (high PMNPs, HMNPs) wt.% (Figure 2b). To investigate the effect of primary ligand on MNCs, the Selleckchem MK 8931 interactions of oleic acid molecules on the surface of MNPs were analyzed through derivative weight curves of the three samples of PMNPs (Figure 2c). These PMNPs showed three derivative peaks positioned between 25°C and 550°C [28–30]. The first peak positioned at approximately 250°C (Figure 2c, i) was due to the removal of free oleic acid molecules surrounding the MNPs (Figure 2d,

i), consistent with the derivative peak of pure oleic acid (Additional file 1: Figure S2). The second peak positioned at approximately 350°C (Figure 2c, ii), which was close to the boiling temperature of oleic acid, indicated bilayered oleic acid molecules with hydrophobic interactions between hydrocarbon tails (Figure 2d, ii). The third peak at approximately 450°C (Figure 2c, iii) corresponded to oleic acid molecules covalently bound to MNPs (Figure 2d, iii). The characteristic peaks of the oleic acid-MNP conjugates from asymmetric and symmetric COO− stretches of oleic

acid (1,630 find more and 1,532 cm−1) were confirmed by FT-IR spectroscopy (Additional file 1: Figure S3 and Table S1) and were categorized as a chelating bidentate complex: peak separation as Interleukin-3 receptor 98 cm−1 = 1,630 to 1,532 cm−1 (Additional file 1: Table S2) [30, 31]. The derivative weight curve of an iron-oleate precursor used for MNP synthesis also agreed with the derivative peaks of PMNPs (Additional file 1: Figure S4). From these results, it was determined that LMNPs contained mostly surface-bound oleic acid molecules showing a sharp peak approximately 450°C (Figure 2c, red line). Increased oleic acid in MMNPs formed a surface bilayer, which showed as an additional derivative peak at approximately 350°C (Figure 2c, blue line). The appearance of a sharp peak at approximately 250°C in HMNPs represented excess free oleic acid molecules (Figure 2c, black line). Therefore, we expected that (1) LMNPs were more likely to agglomerate and form large dense MNCs, (2) MMNPs would undergo less self-assembly and form smaller MNCs compared with LMNPs, and (3) excess free oleic acid in HMNPs would disrupt the assembly of individual MNPs to form MNCs. Following primary-ligand modulation, PMNPs were then emulsified with the nanoemulsion method, using polysorbate 80 as a secondary ligand to fabricate MNCs.

In addition, evidence suggests that influenza A virus infection reduces

or promotes the expression of the host miR-141 in a time dependent manner. We found that TGF-β2 mRNA was suppressed in miR-141 overexpressed cells. Our observation is in line with another study showing that the 3′UTR of TGF-β2 mRNA Ion Channel Ligand Library purchase contained a target site for miR-141/200a Tipifarnib solubility dmso and the expression of TGF-β2 was significantly decreased in miR-141/200a transfected cells [22]. Furthermore, miR-141 may not only work as translational repressors of target mRNAs, because it was observed that they also caused a decrease in TGF-β2 mRNA levels. These findings are similar to recent data demonstrating that some miRNAs can alter the mRNA levels of target genes [31]. This ability is probably independent of the ability of these miRNAs to regulate the translation of target mRNAs [14]. We also noted that antagomiR-141 moderately increased the accumulation of TGF-β2 protein during influenza virus infection. LXH254 cost This might be because, by the use of anti-miR miR-141 inhibitor, which

decreases the cellular pool of miR-141, the translation control of the TGF-β2 mRNA was subsequently released and caused the TGF-β2 protein to express and accumulate during virus infection. However, it was also observed that when there was an increase in TGF-β2 mRNA level, the corresponding TGF-β2 protein expression level would be increased, except in the case of non-miR-141-inhibitor treated H5N1 infected cells. In this case, there was a decrease in

TGF-β2 mRNA level, while the TGF-β2 protein was increased. This might be explained by the fact that TGF-β2 mRNA degradation induced by miR-141 might VEGFR inhibitor be much faster than that of the corresponding protein degradation. Recently, we had also reported that H1N1 was the only subtype that could induce a sustained increase in TGF-β2 at protein level [21]. That observation coincides with our results in this study, showing that H1N1 infection induced a little amount of miR-141 expression, while H5N1 infection induced a higher amount of miR-141 expression at the early phase of infection. As a consequence of the higher amount of miR-141 in H5N1 infection, TGF-β2 expression might be more greatly reduced than that in H1N1 infection. Since TGF-β2 can act as both an immunosuppressive agent and a potent proinflammatory molecule through its ability to attract and regulate inflammatory molecules, it plays a vital role in T-cell inhibition. Furthermore, it has been reported that TGF-β2 inhibits Th1 cytokine-mediated induction of CCL-2/MCP-1, CCL-3/MIP-1α, CCL-4/MIP-1β, CCL-5/RANTES, CCL-9/MIP-1γ, CXCL-2/MIP-2, and CXCL-10/IP-10 [32].

p.R254Q mutation in the aquaporin-2 water channel SCH772984 causing dominant nephrogenic diabetes insipidus is due to a lack of arginine vasopressin-induced phosphorylation. Hum Mutat. 2009;30:E891–903.PubMedCrossRef 29. de Mattia F, Savelkoul PJ, Kamsteeg EJ, Konings IB, van der Sluijs P, Mallmann R, et al. Lack of arginine vasopressin-induced phosphorylation of aquaporin-2 mutant AQP2-R254L explains dominant nephrogenic diabetes insipidus. J Am Soc Nephrol. 2005;16:2872–80.PubMedCrossRef 30. Asai T, Kuwahara M, Kurihara H, Sakai T, Terada Y, Marumo F, et al.

Pathogenesis of nephrogenic diabetes insipidus by aquaporin-2 C-terminus mutations. Kidney Int. 2003;64:2–10.PubMedCrossRef 31. Kamsteeg EJ, Bichet DG, Konings IB, Nivet H, Lonergan M, Arthus MF, et al. Reversed polarized delivery of an aquaporin-2 mutant

causes dominant nephrogenic diabetes insipidus. J Cell Biol. 2003;163:1099–109.PubMedCrossRef 32. Sohara E, Rai T, Yang SS, Uchida K, Nitta K, Horita S, et al. Pathogenesis and treatment ABT 263 of autosomal-dominant nephrogenic diabetes insipidus caused by an aquaporin 2 mutation. Proc Natl Acad Sci USA. 2006;103:14217–22.PubMedCrossRef”
“Introduction Vascular endothelial cells (VECs) are known to play important roles in the exchange of oxygen and nutrients with carbon dioxide and metabolites in the microenvironment of organs or tissues. However, apart from this general role, VECs also have organ- or tissue-specific functions [1]. Angiotensin-converting enzyme has higher activity in lung VECs than in VECs in other organs [2], suggesting that VECs differ among tissues and organs. The characteristics of VECs have been extensively Dimethyl sulfoxide studied in vitro [3]. However, the in vivo roles of VECs in tissues and organs remain poorly understood. In fact, once cells are isolated from organs or tissues and grown in culture media, their appearance, structure, and selleck screening library protein expression can change dramatically, leading to phenotypic changes of VECs [4, 5]. VECs have also been demonstrated to play pivotal

roles in numerous diseases, such as cancer [6] and diabetes [7]. In the kidney, processes related to injuries or transplant rejection take place on the surface of VECs. Sufficient knowledge about the characteristics of VECs is thus essential to more clearly understand the pathogenesis of kidney diseases. A recent study comparing a comprehensive mass spectrometry (MS)-based proteome with an antibody-based proteome of single type cultured cells demonstrated that most cell-specific or unique proteins are localized at the plasma membrane or in association with the membrane [8]. These results suggested that the specific functions of cells depend largely on their plasma membrane protein profile. MS-based proteomics studies have provided unprecedented information on the protein expression of organs or tissues, as well as the protein components of subcellular multimolecular complexes [9, 10].

All authors read and approved Poziotinib clinical trial the final manuscript.”
“Background Methylsulfonylmethane (MSM) is a naturally occurring nutrient composed of sulfur, oxygen and methyl groups [1]. In the presence of ozone and high-energy ultraviolet light, MSM (along with dimethyl sulfoxide [DMSO]) is formed from dimethyl sulfide, taken up into atmosphere, returned to the earth in rainfall, and taken into the root systems of plants. As such, MSM can be found in small quantities in a variety of foods [2], such as milk, fruits and vegetables (e.g., tomatoes, corn), coffee, and tea. While multiple health-related benefits are attributed to sulfur in general [3], and to MSM specifically—ranging from improved physical

function [4] to a potential reduction in certain cancer risk [5], the proposed mechanisms of action for MSM appear related to both anti-inflammatory [6]

and anti-oxidative activity [7]. MSM may inhibit the translocation of the p65 subunit of nuclear factor (NF)-kß to the nucleus [6], thus minimizing downstream events associated with local and systemic inflammation. Indeed, supplementation with MSM may AZD3965 solubility dmso minimize the expression of pro-inflammatory cytokines [8]. MSM has been reported to increase antioxidant defense (glutathione) [9], as well as decrease the actual production of reactive oxygen species (ROS) [7]. As with pro-inflammatory biomarkers, supplementation with MSM has resulted in a lowering of multiple oxidative stress biomarkers [10, 11]. Collectively, these findings suggest that MSM might favorably influence exercise recovery, as both inflammation and oxidative stress may be involved in the etiology of exercise-induced muscle damage and associated symptoms [12]. Considering this and the excellent safety profile of MSM, we used a pilot (proof of concept) study design to determine the influence

of MSM on markers of exercise recovery and performance in healthy men. At the time of study conception, we were unaware of any published trials focused on the use of MRIP MSM as a potential exercise recovery agent. We hypothesized that MSM would favorably influence our outcome 3-deazaneplanocin A manufacturer measures (e.g., reduce muscle soreness, reduce muscle fatigue, increase antioxidant capacity), providing justification for further study of this ingredient using a larger scale, placebo controlled study design. Methods Subjects and screening Eight healthy men (27.1 ± 6.9 yrs old) who were considered to be moderately exercise-trained (exercising <150 minutes per week) were recruited to participate in an open label (unblinded) pilot study. Eligibility was determined by completion of a health history form (Physical Activity Readiness Questionnaire [PAR-Q]) and physical examination. All subjects had experience performing resistance exercise, to ensure that the exercise protocol they were exposed to in the present design did not present a novel challenge.

5 (up-regulated genes) and 115 had expression

levels plus one standard deviation of ≤ 0.4 (down-regulated genes). For these genes, 118 upstream intergenic regions were extracted for analysis, after accounting for multiple genes within an operon. The parameters for the Gibbs centroid sampler used on these sequences were the following: up to two motif models were allowed, where each model was specified to be palindromic and 16-24 bases long, a maximum of three sites per intergenic was allowed, a position-specific background model [60] was employed, and centroid sampling was performed with 1000 burn-in iterations, 5000 sampling iterations and 10 random seeds. The results from four independent runs were compared, and the subset of 47 intergenic regions extracted that contained GDC-0449 cost a predicted regulatory motif in at least one of those runs. These 47 intergenic sequences were analyzed with the Gibbs centroid sampler, using the same parameters as above, except that only one motif model was specified. Additional binding TGF-beta inhibitor clinical trial sites were detected using dscan (http://​ccmbweb.​ccv.​brown.​edu/​cgi-bin/​dscan.​pl)

to search the set of promoters for all the genes that exhibited ≥ 2-fold change in expression (Additional file 1). This set included a total of 424 intergenic regions. Acknowledgements We thank Xiaoyun Qiu for advice on the DNA microarray work, Valley Stewart and Joel Klappenbach for advice and discussion. We thank Benjamin K. Amos, Jed Costanza, Qingzhong Wu and Sara H. Thomas for technical assistance in the phenotypic characterization of the EtrA7-1 strain. We also acknowledge members of the Shewanella Federation for helpful discussions. This study was supported by Department of Energy grants

DE-FG02-02ER63342 from the Genomics Program, Office of Biological and Environmental Research very (CB-839 cell line awarded to JMT), DE-FG02-04ER63718.25 from the Environmental Remediation Science Division, Biological and Environmental Research (awarded to FEL) and DE-FG02-04ER63942 from the Genomes to Life Program, Office of Biological and Environmental Research (awarded to LAM). Contributions by MFR and LAM were performed at Pacific Northwest National Laboratory, which is operated by Battelle for the United States Department of Energy under Contract DE-AC05-76RL01830. Electronic supplementary material Additional file 1: Supplemental Table SI1. Genes differentially expressed in anaerobic cultures of MR-1 and Etra7-1 at different concentrations of KNO3. Complete list of genes differentially expressed including relative expression, standard deviation, “”TIGR role”" and predicted EtrA binding sites. (PDF 224 KB) Additional file 2: Figure SI1. Distribution of differentially expressed genes (> 2-fold change) grouped in 19 functional categories in anaerobic cultures of EtrA7-1 compared to the wild type grown on lactate and nitrate. The total of genes down-regulated is 323 and the up-regulated is 289.

Then the cells were incubated with FITC-conjugated CK19 antibody or FITC-mouse IgG1 isotype antibody (both from BD PharMingen) as negative control overnight. After washed twice with permeabilization buffer, samples were BMS202 purchase analyzed by FACSCalibur (Becton Dickinson). Statistical analysis K Related Samples Test was used for the analysis of CK19 expression in peripheral blood of patients before and after clinical treatment. Mann-Whitney U test was used to Rabusertib solubility dmso compare

CK19 expression levels in peripheral blood between patients at stage III and stage IV. The statistical significance was defined as values of p < 0.05. Results CK19 expression in A431 cells Immunofluorescence staining was used to detect the CK19 expression in A431 cells. The result showed that A431 cells were CK19-immunoreactive cells and CK19 was mainly

located in the cytoplasm of A431 cells (Figure 1). Figure 1 Detection of CK19 expression in A431 cells by immunofluoresence staining. A431 cells https://www.selleckchem.com/products/bay-11-7082-bay-11-7821.html were incubated with FITC-conjugated CK-19 antibody (A) or FITC-mouse IgG1 (isotype control) (B) and analyzed the expression of CK19. The scale bar = 20 μm. The specificity and sensitivity of flow cytometry Intracellular flow cytometric analysis indicated that all the A431 cells expressed high level of CK19 (Figure 2A). However, healthy adult peripheral blood white blood cells had no CK19 expression (Figure 2B) (n = 25). A431 cells were mixed with healthy adult white blood cells at different ratios of 1:1, 1:10, 1:102, 1:103, and 1:104 to determine the sensitivity of flow cytometry. It showed that the percentages of CK19+ cells detected by flow cytometry were consistent with the ratios of A431/white blood cells. Flow cytometry could distinguish the very low percentage of CK19 expressing cells, even 1 A431 cell in 104 white blood cells. It suggested that flow cytometry

had specificity and sensitivity to examine CK19 expression and possessed the potential to detect the few circulating breast cancer cells in the whole blood samples (Figure 3). Figure 2 CK19 PTK6 expressions in A431 cells (A) and human white blood cells (B). The cells were fixed, permeabilized with 0.01% Triton X-100, stained with FITC-conjugated mouse anti-human CK19 antibody or FITC-conjugated mouse IgG1 and analyzed by flow cytometry. Figure 3 Expression of CK19 in A431 cells diluted with human white blood cells at different ratios. A431 cells were mixed with healthy adult white blood cells at different ratios of 1:1 (A), 1:10 (B), 1:102 (C), 1:103 (D), and 1:104 (E). The cell mixture was stained with FITC-anti-CK19 antibody and detected the expression of CK19. Patient characteristics The characteristics of 48 patients enrolled in the study are listed in Table 1. The age range of patients was from 28 to 82 years old and the median age was 46 years old.

From this gene set 39 genes were W83-specific as they were absent in each of the test strains. In this way the prtT protease gene and a fimbrillin gene (fimA) were found to be aberrant in all test strains, but not W83-specific as they were present in one or more test strains. The results for fimA support the findings that the gene is widely distributed, but variable at the probe locus among P. gingivalis strains. Many of the genes found in this selleck screening library analysis are located within the highly variable regions described in earlier publications using whole-genome analysis. The existence of those regions were supported by data comparing the genome sequences

of P. gingivalis strains W83 and ATCC33277 [28]. Also in this study we found these regions

back in the analysis as described above Genes Akt inhibitor review only aberrant in FDC381 FDC381 is the only strain included in this study that does not produce CPS. It is also the least virulent strain in mouse studies. Here, an GW2580 cost analysis was performed to find genes that are specifically aberrant in FDC381 and not in all the other test strains (Table 7). Alongside many genes encoding hypothetical proteins several genes of special interest were found. The genes PG1711 encoding an alpha-1,2-mannosidase family protein, and PG1972 encoding the hemagglutinin hagB, all thought to be involved in virulence either by a role in evasion of the immune system or by a role in adhesion to host cells [29, 59]. Table 7 Genes only aberrant in strain FDC381 GeneID Annotated function PG0183 lipoprotein, Miconazole putative PG0204 hypothetical protein PG0300 TPR domain protein PG0492 hypothetical protein PG1119 flavodoxin, putative PG1199 hypothetical protein PG1200 hypothetical protein PG1373 hypothetical protein PG1466 hypothetical protein PG1467 methlytransferase, UbiE-COQ5 family PG1473 conjugative transposon protein TraQ PG1685 hypothetical protein PG1711 alpha-1,2-mannosidase family protein PG1777 conserved

hypothetical protein PG1786 hypothetical protein PG1814 DNA primase PG1969 hypothetical protein PG1970 hypothetical protein PG1972 hemagglutinin protein HagB PG1977 hypothetical protein PG1978 hypothetical protein Although these data do not directly show any CPS biosynthesis specific genes aberrant only in the non-encapsulated FDC381 it does give hints towards other virulence associated traits that are missing in FDC381. High versus lower virulence strains When comparing the core gene set of only the highly virulent strains W83, HG1025, ATCC49417 and HG1690 with the genes aberrant in each of the less virulent strains HG184, HG1691, 34-4 and FDC381 an interesting result was seen. There is only a single gene, hmuS, that is present in all highly virulent strains but aberrant in each of the less virulent strains. HmuS is part of the hmuYRSTUV haemin uptake system [60].

The fluorescence intensity of the Rabusertib supplier ECCNSs and etoposide is in agreement with the results from CLSM images. Figure 10 SGC- 7901 cells were treated with 30 μg /mL etoposide in two forms of ECCNSs (f, g, and h) and void etoposide (b, c, and d). As the plots show, the number of events (y-axis) with high fluorescence intensity (x-axis) increases

by 4-h incubation with ECCNSs but without any evident change for void etoposide. Negative control (a and e) includes nontreated cells to set their auto-fluorescence as ‘0’ value. Controlled selleck chemicals llc delivery of drug using carrier materials is based on two strategies: active and passive targeting. The former is technical sophisticated and suffering from many difficulties. Otherwise, the latter is easier to implement practically [46]. Many formulations have been used in the representative passive-targeting strategies based on the EPR effect [47]. Tumor vessels are often dilated and fenestrated due to rapid formation of vessels that can serve the fast-growing tumor while normal tissues contain capillaries with tight junctions

that are less permeable to nanosized particle [11, 48]. The EPR effect is that macromolecules can accumulate in the tumor at concentrations five to ten times higher than in normal tissue within 1 to GW3965 price 2 days [49]. Besides, biomaterials with diameters more than 100 nm tend to migrate toward the cancer vessel walls [50]. Therefore, the EPR effect enables ECCNSs aminophylline (secondary nanoparticles) to permeate the tumor vasculature through the leaky endothelial tissue and then accumulate in solid tumors. On one hand, the uptake of ECCNSs by tumor cells can lead to the direct release of etoposide into intracellular environment to kill tumor cells.

On the other hand, the pH-sensitive drug release behavior for ECCNSs may lead to the low release of etoposide from ECCNSs in pH neutral blood, and the rapid release of the drug in relatively acidic extracellular fluids in the tumor. In this way, the targeted delivery of etoposide to tumor tissues may be possible by ECCNSs. Referring to some previous reports [51, 52], the possible mechanism for the targeted delivery of the ECCNSs is illustrated in Figure 11. Most of the biodegradable ECCNSs decompose into the secondary nanoparticles in the vicinity of the tumor endothelium, with the release of epotoside. The small therapeutic nanoparticles and drugs readily pass through the endothelia into tumor tissues for efficient permeability [53]. The degradation of the materials in the endosomes or lysosomes of tumor cells may determine the almost exclusive internalization along clathrin-coated pits pathway. The multistage decomposition of ECCNSs in blood vessels or tumor tissue is likely to play a key role in determining their targeting and biological activity [54]. Figure 11 A representative illustration of ECCNSs targeting.