Functional cooperation of miR-125a, miR-125b, and miR-205 in entinostat-induced downregulation of erbB2/erbB3 and apoptosis in breast cancer cells

We reported that the class I HDAC inhibitor entinostat induced apoptosis in erbB2-overexpressing breast cancer cells via downregulation of erbB2 and erbB3. Here, we study the molecular mechanism by which entinostat dual-targets erbB2/erbB3. Treatment with entinostat had no effect on erbB2/erbB3 mRNA, suggesting a transcription-independent mechanism. Entinostat decreased endogenous but not exogenous erbB2/erbB3, indicating it did not alter their protein stability. We hypothesized that entinostat might inhibit erbB2/erbB3 protein translation via specific miRNAs. Indeed, entinostat significantly upregulated miR-125a, miR-125b, and miR-205, that have been reported to target erbB2 and/or erbB3. Specific inhibitors were then used to determine whether these miRNAs had a causal role in entinostat-induced downregulation of erbB2/erbB3 and apoptosis. Transfection with a single inhibitor dramatically abrogated entinostat induction of miR-125a, miR-125b, or miR-205; however, none of the inhibitors blocked entinostat action on erbB2/erbB3. In contrast, co-transfection with two inhibitors not only reduced their corresponding miRNAs, but also significantly abrogated entinostat-mediated reduction of erbB2/erbB3. Moreover, simultaneous inhibition of two, but not one miRNA significantly attenuated entinostat-induced apoptosis. Interestingly, although the other HDAC inhibitors, such as SAHA and panobinostat, exhibited activity as potent as entinostat to induce growth inhibition and apoptosis in erbB2-overexpressing breast cancer cells, they had no significant effects on the three miRNAs. Instead, both SAHA- and panobinostat-decreased erbB2/erbB3 expression correlated with the reduction of their mRNA levels. Collectively, we demonstrate that entinostat specifically induces expression of miR-125a, miR-125b, and miR-205, which act in concert to downregulate erbB2/erbB3 in breast cancer cells. Our data suggest that epigenetic regulation via miRNA-dependent or -independent mechanisms may represent a novel approach to treat breast cancer patients with erbB2-overexpressing tumors.

Efficiency of endovenous versus arterial administration of mesenchymal stem cells for ischemia-reperfusion-induced renal dysfunction in rats

BACKGROUND

Ischemia followed by reperfusion leads to acute renal failure in both native kidneys and a renal allograft. Our previous study found that transplantation of mesenchymal stem cells (MSCs) ameliorated ischemia-reperfusion (I/R)-induced kidney dysfunction by increasing the activities of antioxidant enzymes. The purpose of this study was to evaluate whether intra-arterial versus intravenous administration was more effective.

METHODS

Renal ischemia was induced by clamping the right renal vessels for 60 minutes after removal of the left kidney. MSCs (1 × 10(6)) were administered through either the tail vein (TV) or the renal arter (RA), followed by reperfusion. We evaluated kidney function as well as tissue activities of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). Histopathologic and immunohistochemical examinations were performed. To tracking MSCs in vivo, they were transfected with firefly luciferase and monomeric red fluorescent protein reporter genes (fluc-mrfp). MSC retention and survival were assessed using bioluminescence imaging. We observed the effects of MSCs (1 × 10(6), 2 × 10(6), and 5 × 10(6)) on IR injury.

RESULTS

MSC infusion via either the tail vein or the renal artery significantly improved kidney function at days 1, 3, and 5 as indicated by lower urea and creatinine levels compared with vehicle controls (P < .05). I/R induced a reduction in renal tissue SOD activity but GSH-PX was significantly improved by MSCs (P < .05) on day 1. Treatment with MSCs also significantly reduced renal tissue MDA levels that had been otherwise increased by renal I/R injury (P < .05). The above parameters were similar between the TV and the RA groups. Histological examination revealed kidneys from MSC-treated rats to show fairly normal morphology. The percentages of proliferating cell nuclear antigen (PCNA)-positive cells were higher in the MSC groups: 16.83 ± 4.62%, 19.17 ± 6.21%, and 2.17 ± 1.16% for the TV, RA, and control groups, respectively. There was no significant dose-related difference among MSC groups. Bioluminescence imaging demonstrated most MSCs to be lost within 7 days after either intravenous or intra-arterial infusion.

CONCLUSIONS

MSCs ameliorated I/R-induced acute renal failure in rats with similar efficiency whether infused either through the TV or the RA. There was no dose-dependent responses.

Injectable and biodegradable thermosensitive hydrogels loaded with PHBHHx nanoparticles for the sustained and controlled release of insulin

Biodegradable PHBHHx (poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)) nanoparticles containing insulin phospholipid complex were loaded in chitosan-based thermosensitive hydrogels for long-term sustained and controlled delivery of insulin. The injectable hydrogels, prepared by adding β-glycerophosphate disodium salt (GP) solution to chitosan (CS) solution under stirring, showed a rapid solution-to-gel transition at 37 °C, a porous structure and a comparative degradation and swelling rate in vitro. In the in vitro release studies, only 19.11% of total insulin was released from the nanoparticle-loaded hydrogel (NP-CS/GP) within 31 days. However, 96.41% of total insulin was released from the free insulin-loaded hydrogel (INS-CS/GP) within 16 days. Most importantly, the hypoglycemic effect of NP-CS/GP following subcutaneous injection in diabetic rats lasted for >5 days, much longer than the effect caused by INS-CS/GP or other long-acting insulin formulations. The pharmacological availability of NP-CS/GP relative to INS-CS/GP was 379.85%, indicating that the bioavailability of insulin was significantly enhanced by NP-CS/GP gels. Therefore, biodegradable and thermosensitive NP-CS/GP gels have great potential for use in novel ultralong-acting insulin injections. In addition, the NP-loaded hydrogel system also paves the way for long-term delivery of other proteins and peptides.

Significance of CD4 T-cell adenosine triphosphate levels monitoring in elderly renal transplant recipients

OBJECTIVES

To find the significance of CD4 T-cell adenosine triphosphate (ATP) levels in elderly renal recipients in correlation with drug doses, levels, and clinical parameters.

METHODS

Drug doses and levels, CD4 T-cell ATP level (162 sequential samples), and other clinical data were collected and assessed among 31 elderly renal recipients who underwent transplantations from November 2007 to March 2011.

RESULTS

Among subjects with stable clinical status, the main ATP levels pretransplantation were not significantly different from those posttransplantation: 302.4 ± 97.5 ng/mL versus 288.8 ± 102.6 ng/mL (P > .05). There was no relationship between ATP levels and tacrolimus concentrations or doses. In 12 patients experiencing infection, the ATP levels were significantly lower then those of subjects showing a stable clinical status: 127.3 ± 92.8 versus 288.8 ± 102.6 ng/mL (P < .01). Six patients with biopsy-proven acute rejection episodes did not show significantly higher ATP levels compared with those who were clinically stable: 26.2 ± 224.8 versus 288.8 ± 102.6 (P > .05).

CONCLUSIONS

CD4 T-cell ATP levels were valuable to monitor immunosuppression among elderly renal transplant recipients.

Image texture features as indicators of beef tenderness

Image processing techniques were developed to predict cooked-beef tenderness from fresh-beef image characteristics. Cattle from different finishing treatments were processed in a commercial plant. Two short loin steaks were sampled from each carcass; one used for sensory evaluation and the other for imaging. The samples varied significantly in both US quality grades and sensory tenderness scores. Color, marbling and texture features were extracted from the beef images. Statistical and neural network analyses were performed to relate the image features to sensory tenderness scores. Image texture features were found to be useful indicators of beef tenderness. Partial least squares and neural network models were able to predict beef tenderness from color, marbling and image texture features to R(2)-values up to 0.70.

Dapsone 5% gel: a new option in topical therapy for acne

Dapsone 5% gel for the topical treatment for acne vulgaris was recently introduced in Canada. It represents the first new anti-acne agent to gain North American regulatory approval in the past decade. Dapsone's utility is attributable to its anti-inflammatory and antimicrobial properties that improve both inflammatory and non-inflammatory acne, with more prominent effects occurring in inflammatory lesions. Short- and long-term safety and efficacy have been demonstrated. Especially for patients exhibiting sensitivities or intolerance to conventional anti-acne agents, topical dapsone is a novel addition to the treatment armamentarium.

Non-fouling biomaterials based on blends of polyethylene oxide copolymers and polyurethane: simultaneous measurement of platelet adhesion and fibrinogen adsorption from flowing whole blood

Measurements of platelet adhesion and fibrinogen adsorption from flowing whole blood to a series of polyethylene oxide (PEO)-based materials were carried out. A unique experimental design was used in which both quantities were measured in the same experiment. The materials consisted of a polyurethane (PU) as a matrix into which various triblock copolymers of general structure PEO-PU-PEO were blended; the PU block was the same in all materials but the PEO blocks ranged in molecular weight from 550 to 5000. Platelets were isolated from fresh human blood and labeled with (51)Cr; purified fibrinogen was labeled with (125)I. A whole blood preparation containing these labeled species was used for the adhesion/adsorption studies. The surfaces were exposed to the flowing blood in a cone and plate device at a wall shear rate of 300 s(-1). It was found that both platelet adhesion and fibrinogen adsorption decreased with increasing copolymer content in the blends and with decreasing PEO block size for a given copolymer content. The block size effect was due probably to higher PEO surface coverage for the lower molecular weight blocks. Fibrinogen adsorption and platelet adhesion were linearly and strongly correlated. The best performing materials showed very low fibrinogen adsorption of the order of 25 ng/cm(2), and correspondingly low platelet densities around 10,000 per cm(2), i.e. fractional platelet coverage in the vicinity of 0.2%.

WE-G-217BCD-07: Implementation and Evaluation of Helical On-Board CBCT and Exact Image Reconstruction

PURPOSE

Longitudinal coverage of CBCT, which is 17 cm for head scan and 15.5 cm for body scan, is not enough to cover the entire PTV for over 90% of head/neck and gastrointestinal/genitourinary/gynecologic patients if lymph nodes are involved. Helical CBCT, which was accomplished using external beam LINAC in its research mode, is one promising way to extend the CBCT longitudinal coverage. Aim of this study is to compare Katsevich's exact algorithm with traditional FDK algorithm for helical CBCT image reconstruction.

METHODS

CBCT projection raw data were acquired on a TrueBeam LINAC machine (Varian Medical Systems) in the research mode in helical trajectories that encompass a 360 degree rotation, 25 cm pitch, 100 kVp, 80 mA, and 25 ms, with a Catphan 600. Reconstruction was done with Katsevich's exact and FDK approximate algorithms. Scatter correction, beam-hardening correction, and non-uniform gantry angle correction, are performed on projection data to reduce artifacts and noise. Image qualities (CT number accuracy, uniformity, SNR) were evaluated and compared between the reconstruction algorithms.

RESULTS

Images reconstructed by Katsevich's algorithm show better qualities, compared to ones by FDK algorithm and HU numbers have higher uniformity and accuracy. The HU-density calibration curve closely conforms to the manufacturer recommended values. The level of noise computed as the standard deviation in the phantom uniform region is 28.07 for the Katsevich algorithm, compared to 44.64 for the FDK algorithm.

CONCLUSIONS

Katsevich's exact reconstruction algorithm provided better image qualities than FDK for helical CBCT scans. This result will very useful for our ongoing investigation of helical CBCT, which would lead to improvement of CBCT longitudinal coverage of PTV and would be essential for future image-guided adaptive radiation therapy applications. Varian Research Agreement with Washington University in St. Louis.