Smart multilayered assembly for biocompatible siRNA delivery featuring dissolvable silica, endosome-disrupting polycation, and detachable PEG

Multifunctional delivery systems of small interfering RNA (siRNA) are needed to overcome the intrinsic biological barriers toward efficient gene silencing in the cell cytoplasm. In this report, a smart multilayered assembly (SMA) was fabricated by a layer-by-layer method with polyionic materials. The SMA was designed to feature a siRNA-loaded core, a transiently core-stabilizing silica interlayer, an endosome-disrupting polycation interlayer, and a biocompatible poly(ethylene glycol) (PEG) shell with reductive environment-responsive detachability. The SMA was confirmed to be approximately 160 nm in size with narrow distribution and spherical morphology by DLS and TEM analyses. The PEG detachability of the SMA based on disulfide cleavage was also confirmed by the increase in both ζ-potential and size due to the exposure of the polycation interlayer and the compromised colloidal stability. The silica interlayer rendered the SMA highly tolerant to dissociation induced by anionic lipids, while after 24 h dialysis siRNA release from the SMA was clearly observed, presumably due to gradual dissolution of the silica interlayer based on the equilibrium shift to silicate ions. The entrapment ratio of siRNA delivered by the SMA within the endosome was significantly lower than that by nondisulfide control (NDC) without PEG detachability, suggesting the improved endosomal escape of SMA with the exposed, endosome-disrupting interlayer after PEG detachment. SMAs induced significantly higher gene silencing efficiency in various cultured cells, compared to NDC, without associated cytotoxicity. The systemic administration of SMAs for subcutaneous tumor-bearing mice achieved significant endogenous gene silencing in tumor tissue without hematological toxicity.

Accelerated polymer-polymer click conjugation by freeze-thaw treatment

Herein, we report a unique technique to accelerate polymer-SNA conjugation based on copper-free click chemistry: gradual freeze-thawing of the reaction solution substantially increases the conjugation rate possibly because of the reactant concentration at the microenvironment scale. This technique was applied to the conjugation between a small interfering RNA (siRNA) and PEG in an aqueous buffer at/below room temperature.

Optimal patient selection for CPT-11 chemotherapy in colorectal cancer: Quantitative prediction of tumor response and overall survival using expression data of novel marker genes

e14529

Background: Unlike the toxicity, none of the critical prediction markers of CPT-11 efficacy has been validated to date. With a hypothesis that expression analysis of a set of the key drug sensitivity genes could allow us to predict the therapeutic response, we identified potent marker genes for CPT-11 in in vitro, conducted this prospective study attempting to develop a prediction formula of efficacy using the expression data (2006 ASCO, 2006 ESMO), and demonstrated the latest prediction formula of the best tumor response (BTR), time to treatment failure (TTP), and the overall survival after CPT-11 chemotherapy (OS). Methods: Seven genes identified as possible marker genes for CPT-11 (SN-38)- AMD1, CTSC, EIF1AX, FLJ13089 , DDX54, PTPN2, and TBX3-, and 5 other possible marker genes (ABCG2, CYP3A4, MGMT, POR, and TOP2A) that had already been known as drug sensitivity determinants and selected by our in vitro screening process, were studied. CPT-11 was intravenously administered on Days 1, 8, and 15, every 4 weeks in chemo-naive patients with stage IV colorectal cancer after palliative operation. Tumor samples were collected at surgery and tumor response was evaluated by RECIST. Results: All of the 44 enrolled patients were assessable for BTR (% of initial tumor size), TTP (day), and OS (day) in the clinical study, and we successfully developed the best linear model for each, which converted the quantified expression data of the 7 selected genes into objective BTR, TTP, and OS. We used 20, 16, and 15 tumor specimens and constructed potent prediction formulae for BTR (r=0.9420), TTP (r=0.7103), and OS (r=0.8406), respectively. Utility-confirmation analyses using another 16, 10, 13 clinical samples appeared to show that the formulae could predict BTR (r=0.6491, p=0.007) and OS (r=0.7947, p=0.011). We also fixed the best linear models using 5 other known marker genes, but they had less advantage in prediction. Conclusions: Despite limited data, our developed formulae using the 7 novel genes would provide advantages in prediction of individual response to CPT-11. Based on the positive results of this study, we have initiated a large scale validation study of the formula.

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Limited VH gene usage in B-cell clones established with nurse-like cells from patients with rheumatoid arthritis

OBJECTIVES

Nurse-like stromal cells (NLC) in synovia and bone marrow of patients with rheumatoid arthritis (RA) can support pseudoemperipolesis, protect from apoptosis and enhance immunoglobulin production of peripheral blood B cells isolated from healthy individuals, suggesting the profound contribution of hyperactivation of B cells in RA. In the course of establishing RA-NLC from RA patients, we observed the growth of B cells in the presence of RA-NLC.

METHODS

We cloned B cells from the synovium or bone marrow of RA patients using the limiting dilution technique. For established clones, nucleotide sequences of immunoglobulin and surface antigens were investigated. To investigate the dependence of these clones on NLC, differences in the proliferation and the amount of immunoglobulin produced in the presence or absence of NLC were compared. Immunocytochemical staining of various cells was performed using the antibody these clones produced.

RESULTS

Nine B-cell clones established from RA patients showed RA-NLC-dependent growth. These B-cell clones expressed CD19, CD20, CD38, CD39 and CD40, suggesting that the cloned cells were mature and activated. All clones secreted immunoglobulins in culture media, which were specific for intracellular components of various cell lines, including RA-NLC. Interestingly, we found limited usage of immunoglobulin heavy-chain variable regions (VH) among B-cell clones from RA patients. These repertoires were reported to be detected preferentially in fetal livers.

CONCLUSION

The present study provides a novel insight into the involvement of RA-NLC in the immunopathogenesis of RA via an autoreactive B cell development and/or activation mechanism.

Myocardial performance index for assessment of left ventricular outcome in successfully recanalised anterior myocardial infarction

OBJECTIVE

To investigate whether the myocardial performance index (MPI) can predict left ventricular functional outcome in patients with early recanalisation after anterior acute myocardial infarction (MI) and to determine when the index should be measured.

DESIGN

MPI was measured serially by two dimensional Doppler echocardiography after successful percutaneous coronary intervention (PCI). Left ventricular function was evaluated by echocardiography and left ventriculography. To assess coronary microvascular damage, the coronary flow velocity pattern was measured immediately after PCI with a Doppler guidewire.

SETTING

Hiroshima City Asa Hospital.

PATIENTS

32 consecutive patients with their first anterior acute MI who had complete occlusion of left anterior descending coronary artery.

INTERVENTIONS

Successful PCI within six hours of symptom onset.

MAIN OUTCOME MEASURES

Left ventricular anterior wall motion score index (A-WMSI), left ventricular end diastolic pressure (LVEDP), left ventricular ejection fraction (LVEF), and left ventricular end diastolic volume (LVEDV).

RESULTS

There was a significant negative correlation between MPI on day 2 and the coronary diastolic deceleration time (r = -0.66, p < 0.002), as well as a significant positive correlation with the coronary diastolic deceleration rate (r = 0.74, p < 0.0001). MPI on day 2 was significantly correlated with the short and long term changes of A-WMSI and with the short term changes of LVEDP. Furthermore, MPI on day 2 was significantly correlated with the short and long term changes of LVEF (r = -0.52, p < 0.003, and r = -0.64, p < 0.0008, respectively) and of LVEDV (r = 0.51, p < 0.003, and r = 0.41, p < 0.05, respectively).

CONCLUSIONS

Doppler derived MPI on day 2, representative of the early coronary microvascular state, can predict the left ventricular functional outcome after early successful recanalisation of a patient's first anterior acute MI.

A homogeneous caspase-3 activity assay using HTRF technology

Caspases are cysteine proteases presenting a conserved active site that cleaves protein substrates at a highly specific position. They are involved in different aspects of the active cell death pathway. Most of them act through proteolytic degradations of cellular components. This paper describes the assay development, assay validation, and screening for inhibitors of this enzyme, which could be potential drug candidates. The assay uses homogeneous time-resolved fluorescence based on energy transfer from europium cryptate as donor to cross-linked allophycocyanin as acceptor (XL665). A double-tagged substrate, biotinyl-epsilon-aminocaproyl-L-aspartyl-L-glutamyl-L-valyl-Laspartyl-L-alanyl-L-propyl-N(epsilon)-(2,4-dinitrophenyl)-L-lysine-amide (biotin-X-DEVDAPK(dnp)-NH(2)), is conjugated with streptavidin cryptate and anti-dnp-XL665 monoclonal antibody. The close proximity between donor and acceptor induces a specific time-resolved fluorescence signal. In the presence of enzyme activity, the substrate cleavage induces an unlinking of the two fluorescent probes and, subsequently, the disappearance of the specific signal as a result of loss of proximity. Experiments to optimize the reagent concentration, incubation times, precision, reproducibility, and robustness are discussed in comparison with a fluorometric method.

Correlation of beta-catenin and cyclin D1 expression in colon cancers

OBJECTIVE

Beta-catenin activates transcription by TCF/LEF and has been regarded as an oncogene in a wide range of malignant tumors. Among various molecules regulated by beta-catenin/Tcf, cyclin D1 is the most likely candidate for stimulation of the oncogenic pathway. The association between beta-catenin and cyclin D1 was investigated using clinical samples from colorectal cancers.

METHODS

The expression of beta-catenin and cyclin D1 was investigated by immunohistochemical analyses of samples from 70 patients with colorectal cancers. In 28 of the fresh tumor samples, beta-catenin protein was separated into soluble and insoluble fractions and quantitatively correlated with cyclin D1 protein by Western blot analysis.

RESULTS

Compared with noncancerous epithelium, beta-catenin and cyclin D1 were overexpressed (+) in 35 (50%) and 30 cases (43%), respectively. Cyclin D1 (+) was observed in 74% (26/35) of beta-catenin (+) cases, but only in 11% (4/35) of the beta-catenin (-) cases. Thus, there was a strong association between the expression of beta-catenin and that of cyclin D1 (p < 0.001). In the Western blot analysis, the amount of cyclin D1 correlated well with beta-catenin expression in the soluble fraction (p = 0.0016), but not with beta-catenin in the insoluble fraction or with E-cadherin expression. Beta-catenin (-)/cyclin D1 (-) cases displayed less tumor invasion than the remaining cases. However, there were no significant differences in lymph node metastasis or other clinicopathological findings.

CONCLUSION

Our results indicate that beta-catenin overexpression in the cytoplasm may promote malignant transformation by triggering cyclin D1 expression in colorectal cancers.

Cycloprodigiosin hydrochloride, a H+/Cl- symporter, induces apoptosis in human colon cancer cell lines in vitro

Recently, we reported that cycloprodigiosin hydrochloride (cPrG.HCl), a novel H+/Cl- symporter, induces acidification of the cytosol and leads to apoptosis on rat and human liver cancer cells. In the present study, the effects of cPrG.HCl, a H+/Cl- symporter, were examined in colon cancer cell lines in vitro. In the MTT assay, cPrG.HCl inhibited the growth of two colon cancer cell lines (WiDr and SW480) in a dose- and time-dependent manner. The cPrG.HCl treatment of both types of cells induced apoptosis as confirmed by the appearance of a sub-G1 population and intranucleosomal DNA fragmentation. In addition, cPrG.HCl lowered pHi (below pH 6.8) respectively. Therefore, these results suggest that cPrG.HCl may be useful for the treatment of colon cancer cells.

Overexpression of CDC25B overrides radiation-induced G2-M arrest and results in increased apoptosis in esophageal cancer cells

CDC25B phosphatase plays a key role in controlling G2-M progression by dephosphorylating two inhibitory residues of CDC2 and also has been suggested to have an oncogenic property. In this study, we investigated the effect of CDC25B overexpression on radiation-induced G2-M arrest and radiation sensitivity in esophageal cancer cells. TE8-CDC25B, in which CDC25B was overexpressed under an inducible system, was more radiosensitive than the vector control (TE8-neo) in a clonogenic survival assay. Without radiation, CDC25B overexpression had little effect on cell cycle fractions or growth rate. After 10-Gy radiation, TE8-CDC25B showed decreased G2-M arrest and increased apoptosis, whereas TE8-neo displayed prolonged G2-M arrest and less apoptosis. During this period, there were no differences in the protein amounts of CDC2 and cyclin B1 between the two cell lines. However, more CDC25B expression, which was reduced immediately by radiation, was sustained in TE8-CDC25B than in TE8-neo. Moreover, induction of tyrosine phosphorylation of CDC2 and reduction of CDC2 kinase activity after irradiation was less significant in TE8-CDC25B than in TE8-neo. These results indicate that cancer cells that overexpress CDC25B override G2-M arrest by retaining CDC2 kinase activity and undergo apoptosis after radiation. This may point to an effective approach toward improving radiotherapy outcomes of various cancers.

Localization of IQGAP1 is inversely correlated with intercellular adhesion mediated by e-cadherin in gastric cancers

Down-regulation of E-cadherin function is characteristic of cancer cells and might involve the small G-protein Rho family, including Rac1 and Cdc42. IQGAP1 has been reported to be one of the target proteins of Rac1 and Cdc42. To elucidate the role of IQGAP1 in cancer-cell adhesion, its expression was investigated in 47 cases of human gastric cancer by immunohistochemistry and Western blot upon protein fractionation, especially in comparison with E-cadherin and catenin expression. In the non-cancerous columnar epithelium of the stomach, IQGAP1, as well as E-cadherin/catenin, was expressed at the cell-cell boundary. IQGAP1 was frequently observed diffusely in the cytoplasm in intestinal-type tumors (20/22 cases) but was expressed at the cell membrane in diffuse-type tumors (19/25 cases), thus showing significant association with tumor differentiation (p < 0.01). Interestingly, membranous expression of IQGAP1 was inversely correlated with that of E-cadherin (p < 0.05) or alpha-catenin (p < 0.001). These observations were consistent with the Western blot results following protein fractionation. IQGAP1 was dominantly expressed in the soluble fraction in differentiated tumors; however, in undifferentiated tumors, it was mostly in the insoluble fraction. In contrast, both E-cadherin and alpha-catenin were detected only in the insoluble fraction. Thus, subcellular localization of IQGAP1 from the cytoplasm to the cell membrane was correlated with E-cadherin dysfunction and tumor dedifferentiation in gastric carcinogenesis.

Morphological analyses of the human tongue musculature for three-dimensional modeling

Skilled movements of the tongue in speech articulation reflect complex formation of the tongue musculature, although its description in the anatomical literature is rather limited for developing a realistic computational model of the tongue. This study presents detailed descriptions of the muscular structure of the human tongue based on macroscopic and microscopic observations and provides three-dimensional schemata of the tongue musculature. Histologic examination revealed that the tongue consists of five strata, stacked along the courses of the fibers of the genioglossus muscle in proximal-distal directions. This stratum structure exists in the entire tongue tissue, indicating that the lingual musculature can be divided into the inner and outer regions. The former consisted of the "stem" and "core," and the latter of the "cover" and "fringe." In gross dissection, the tongue was cut into wedge-like blocks along the course of the genioglossus muscle to examine muscle fiber arrangement. Using this approach, it was determined that serial repetitions of "structural units" composed the inner musculature of the tongue. Each unit consisted of a pair of thin muscle fiber laminae; one was composed of the genioglossus and vertical muscles, and the other of the transverse muscle. In the apex, the laminae lacked the fibers of the genioglossus. These findings have been incorporated in three-dimensional schemata of the tongue musculature.