Ultrasound triggered cell death in vitro with doxorubicin loaded poly lactic-acid contrast agents

Traditional chemotherapy generally results in systemic toxicity, which also limits drug levels at the area of need. Two ultrasound contrast agents (UCA), with diameters between 1-2 microm in diameter and shell thicknesses of 100-200 nm, composed of poly lactic-acid (PLA), one loaded by surface adsorption and the other loaded by drug incorporation in the shell, were compared in vitro for potential use in cancer therapy. These poly lactic-acid (PLA) UCA platforms contain a gas core that in an ultrasound (US) field can cause the UCA to oscillate or rupture. Following a systemic injection of drug loaded UCA with external application of US focused at the area of interest, this platform could potentially increase drug toxicity at the area of need, while protecting healthy tissue through microencapsulation of the drug. In vitro toxicity in MDA-MB-231 breast cancer cells of the surface-adsorbed and shell-incorporated doxorubicin (Dox) loaded UCA were examined at 5 MHz insonation using a pulse repetition frequency of 100 Hz at varying pressure amplitudes. Both platforms resulted in equivalent cell death compared to free Dox and US when insonated at peak positive pressure amplitudes of 1.26 MPa and above. While no significant changes in cell death were seen for surface adsorbed Dox-UCA with or without insonation, cell death using the platform with Dox incorporated within the shell increased from 16.12% to 25.78% (p=0.0272), approaching double the potency of the platform when insonated at peak positive pressure amplitudes of 1.26 MPa and above. This mechanism is believed to be the result of UCA rupture at higher insonation pressure amplitudes, resulting in more exposed drug and shell surface area as well as increased cellular uptake of Dox containing polymer shell fragments. This study has shown that a polymer UCA with drug housed within the shell may be used for US-triggered cell death. US activation can be used to make a carrier significantly more potent once in the area of need.

Enhanced 2.0 microm emission and gain coefficient of transparent glass ceramic containing BaF2: Ho3+,Tm3+ nanocrystals

Transparent glass ceramic containing BaF(2):Ho(3+),Tm(3+) nanocrystals has been prepared by melt quenching and subsequent thermal treatment. The precipitation of BaF(2) nanocrystals was confirmed by X-ray diffraction and high-resolution transmission electron microscopy. Intense 2.0 microm fluorescence originating from Ho(3+): (5)I(7) --> (5)I(8) transition was achieved upon excitation with 808 nm laser diode. A large ratio of forward Tm(3+) --> Ho(3+) energy transfer constant to that of backward process indicated high efficient energy transfer from Tm(3+)((3)F(4)) to Ho(3+)((5)I(7)), benefited from the reduced ionic distances of Tm(3+)-Tm(3+) and Tm(3+)-Ho(3+) pairs and low phonon energy environment with the incorporation of rare-earth ions into the precipitated BaF(2) nanocrystals. The results indicate that glass ceramic is a promising candidate material for 2.0 microm laser.

Mitochondrial dysfunction resulting from loss of cytochrome c impairs radiation-induced bystander effect

Cytochrome c is a pivotal protein that resides in mitochondria as component of mitochondria respiration and apoptosis initiator. Using murine cells lacking cytochrome c, we showed here that cytochrome c-deficient cells had attenuated reactive oxygen species/nitric oxide and micronuclei induction to radiation-induced bystander signals, indicating cytochrome c is essential for the bystander effect.

Therapy-induced expression of NF-kappaB portends poor prognosis in patients with localized esophageal cancer undergoing preoperative chemoradiation

Activated nuclear factor-kappa B (NF-kappaB) in the pretreatment cancer tissue of patients with localized esophageal adenocarcinoma (LEA) undergoing preoperative chemoradiation is associated with poor prognosis. It is known that constitutively activated NF-kappaB prior to any therapy portends poor prognosis, and it is also known that activated NF-kappaB in the treated specimen is associated with poor prognosis. However, the prognosis of patients who have treatment-induced activation of NF-kappaB (meaning their cancers activate NF-kappaB during or after therapy) is not been reported. We hypothesized that the treatment-induced activation of NF-kappaB would impart poor prognosis similar to that imparted by constitutively activated NF-kappaB cancer. Patients with LEA who had undergone preoperative chemoradiation plus surgery and had pre- and post-therapy cancer tissue available were selected. Pre- and post-therapy cancer tissues were stained by immunohistochemistry for nuclear staining of NF-kappaB. The overall survival (OS) and disease-free survival were assessed and compared for patients who had intrinsic constitutively activated NF-kappaB cancer with those who had induced activation of NF-kappaB only post-therapy. A total of 41 patients with LEA were investigated. Twenty-five patients had NF-kappaB positive cancer at baseline, and 16 had NF-kappaB negative cancer at baseline but became positive post-therapy. There was no difference in the location, histology grade, clinical stage, or the curative resection (RO) resection rate in the two populations. OS (P = 0.71), disease-free survival (P = 0.86), and median survivals (Converters: 24 months [95% confidence intervals: 7.78 to 40.22]vs. Nonconverters: 34.13 months [95% confidence intervals: 3.54 to 64.27]) were not different between the two groups. Our data suggest that activation of NF-kappaB in response to stress/injury of therapy leads to poor OS. These results need to be confirmed in a larger number of patients. It may be that only pre-therapy evaluation of NF-kappaB is insufficient to assess prognosis of patients with LEA. Additional implications include that when effective anti-NF-kappaB therapies become available, they may have to be considered in patients whose cancers do not have constitutively activated NF-kappaB or cancer may have to be monitored during therapy with biomarker assessments.

Comparative study between slow freezing and vitrification of mouse embryos using different cryoprotectants

The objective of this study was to evaluate the effects of different cryoprotectants and different cryopreservation protocols on the development of mouse eight-cell embryos. Mouse eight-cell embryos were cryopreserved by using propylene glycerol (PROH), ethylene glycerol (EG), dimethyl sulfoxide (DMSO) or glycerol (G) as cryoprotectant with slow-freezing or Vit-Master vitrification protocol. After thawing, the survival rate, blastocyst formation rate and blastocyst hatching rate of the embryos were compared. When the mouse eight-cell embryos were cryopreserved by the slow-freezing, the survival rate, the blastocyst formation rate and the blastocyst hatching rate of the embryos with PROH were significantly higher than those of DMSO and G (p < 0.05, respectively), but not significantly different among those of DMSO, G and EG (p > 0.05, respectively), and not significantly different between those of PROH and EG (p > 0.05, respectively). When the mouse eight-cell embryos were cryopreserved by Vit-Master vitrification, the survival rate, the blastocyst formation rate and the blastocyst hatching rate of the embryos with EG were significantly higher than those of PROH, DMSO and G (p < 0.05, respectively). Yet, there were no significant differences among those of PROH, DMSO and G (p > 0.05, respectively). In conclusion, PROH was the optimal cryoprotectant for the cryopreservation of mouse eight-cell embryos by slow-freezing protocol. EG was the optimal cryoprotectant for the cryopresevation of mouse eight-cell embryos by Vit-Master vitrification protocol, which may be commonly used in clinical and laboratory practice.

Construction of a fusion protein between N-terminal 153 peptide of thrombopoietin and erythropoietin

Thrombopoietin (TPO) functions as a regulator of megakaryocytes in their differentiation and maturation, and is a candidate pharmaceutical for the curing of thrombocytopenia. Erythropoietin (EPO) is a hematopoietic cytokine that regulates the level of red blood cell. It is widely used in renal anemia and tumor associated anemia, and is proved to be safe and effective. In order to study the possibility of using TPO-EPO fusion protein for the curing of anemia and thrombocytopenia induced by high dose chemotherapy, a fusion gene is constructed by linking TPO N-terminal 153 peptideand EPO mature peptide-coding region. The fusion gene is expressed in mammalian cells, revealing that the expression product can support the growth of TPO responsive Ba/F3-mpl cells and EPO dependent Bet-2 cells in the absence of any other stimulating cytokine. It also stimulates the formation of erythroid colonies and megakaryocytic colonies in semi-solid bone marrow cultures. These results indicate that the fusion protein has both thein vitro activities of TPO and EPO. The preliminaryin vivo experiment reveals that the TPO-EPO fusion protein containing cell supernatant raises the platelet level by 37 % in mice, while its function on erythroid hematopoiesis remains to be determined. These results indicate that the construction of TPO-EPO fusion protein and the further study of its use in high dose chemotherapy are possible.

Influence of learning effect on blue-on-yellow perimetry

PURPOSE

Some studies have found that a significant blue-on-yellow perimetry (B/YP) learning effect exists in patients with ocular hypertension (OHT) or open-angle glaucoma who were experienced in standard automated perimetry. However, very little is known about the B/YP learning effect in normal subjects and patients without previous white-on-white perimetry (W/WP) experience. Meanwhile, it is unclear whether the B/YP learning effect is influenced by age and refraction.

METHODS

Twenty healthy subjects, 26 OHT and 14 primary open angle glaucoma (POAG) patients, underwent three full-threshold B/YP tests at intervals of 7 to 21 days. Of the 60 subjects, 38 had no previous W/WP experiences, 22 had previous W/WP experiences for at least two times. The parameters investigated to detect a learning effect were the perimetric indices and the test duration (TD).

RESULTS

Learning effects were demonstrated for mean deviation (MD), pattern standard deviation (PSD), short-term fluctuation (SF), and TD. Significant differences were found between the MD, PSD, SF, and TD of the first test and those of the second and third tests (p<0.05). However, no difference was found between those parameters of the second and third tests. No statistically significant differences were noted in terms of MD1st-2nd, MD1st-3rd, PSD1st-2nd, PSD1st-3rd, TD1st-2nd, and TD1st-3rd between the group with W/WP experience and the group without previous W/WP experience (p>0.05). No statistically significant differences were noted in terms of those parameters among the normal subjects and the patients with OHT or POAG (p>0.05). No significant difference was found in the B/YP learning effect among various age groups (p>0.05) and among various refraction groups (p>0.05).

CONCLUSIONS

A significant learning effect was observed between the first and the second or third tests and the perimetric indices appeared improved at full-threshold B/YP. The previous W/WP experience and the subject age and refraction did not influence the B/YP learning effect. This above all should be taken into account when considering the clinical use of this test to avoid erroneous diagnostic conclusions.

Direct and distant antitumor effects of a telomerase-selective oncolytic adenoviral agent, OBP-301, in a mouse prostate cancer model

We previously constructed OBP-301 (Telomelysin, a telomerase-specific replication-competent adenovirus with human telomerase reverse transcriptase (hTERT) promoter), which showed a strong anticancer effect by inducing cell lysis of human non-small cell lung cancer and colorectal cancer cells. To investigate the utility of OBP-301 for prostate cancer treatment, we herein evaluate the cell killing and antitumor effects. First, in vitro hTERT-specific adenovirus transduction in human prostate cancer cells (LNCaP, PC3, DU145) was confirmed using OBP-401 (Telomelysin-green fluorescent protein (GFP)). There was no detectable GFP transduction in the human prostate normal cells (PrEC, PrSC). Consistently, the cell-killing effect of OBP-301 was observed only in the cancer cells. Second, using an in vivo subcutaneous LNCaP tumor model in nude mice, we demonstrated that three intratumoral OBP-301 injections (10(7) PFU per tumor x 3 days) were sufficient to eradicate the detectable LNCaP prostate tumor. We also demonstrated that the ispilateral treatment with OBP-301 significantly suppressed contralateral LNCaP tumor growth in both sides of the tumor model. Histological and immunohistochemical analyses revealed diffuse oncolytic degeneration and adenoviral E1A protein expression in both sides of the tumors. Therefore, in situ OBP-301 administration could be a promising therapeutic strategy against prostate cancer and its metastatic lesions.

Protective effect of endothelial nitric oxide synthase against induction of chemically-induced diabetes in mice

Since activation of endothelial nitric oxide synthase has been shown to exert protective effects against the metabolic syndrome, while endothelial nitric oxide synthase knockout mice develop hyperinsulinemia and glucose intolerance, we hypothesised that endothelial nitric oxide might play a protective role against induction of diabetes. The role of endothelial nitric oxide in the development of chemically-induced diabetes has been determined using mice in which the bioavailability of endothelial nitric oxide was either increased, through upregulation of endothelial nitric oxide synthase, or absent, through deletion of endothelial nitric oxide synthase gene. Diabetes was induced intraperitoneally with either a single dose of alloxan, streptozotocin, or multiple low doses of streptozotocin and blood glucose monitored twice a week. The role of cyclic guanosine monophosphate was investigated in wildtype mice by treatment with the phosphodiesterase inhibitor, tadalafil, during diabetes induction. Results showed that the incidence of diabetes was markedly decreased in mice overexpressing endothelial nitric oxide synthase, compared to wildtype or endothelial nitric oxide synthase knockout mice, regardless of the method of diabetes induction. Under normal physiological conditions, or during diabetes induction with alloxan or multiple low doses of streptozotocin, blood glucose was significantly lower in mice overexpressing endothelial nitric oxide synthase compared to wildtype or knockout mice. Treatment with tadalafil had no effect on the incidence or severity of diabetes in wildtype mice. We conclude that upregulation of endothelial nitric oxide synthase exerts a protective action against diabetes induction through a direct effect of nitric oxide, independently of cyclic guanosine monophosphate.

Clinical significance of Epstein-Barr Virus DNA load detected pre- and post-radiotherapy in nasopharyngeal carcinoma patients

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Background: Plasma Epstein-Barr virus DNA (EBV DNA) load has been shown to be clinically useful in the detection, monitoring, and prognostication of nasopharyngeal carcinoma (NPC). However, the clinical significance of EBV DNA load detected at different time points has not been addressed to our knowledge. In this study, we investigated whether pre- and post-treatment plasma EBV DNA load have different prognostic implications in NPC patients who were treated with radiotherapy. Methods: Plasma samples from 69 patients with primary NPC were collected before and after radiation treatment, and subjected to a real-time quantitative polymerase-chain- reaction assay of EBV DNA load. The pre-treatment primary tumor volume (GTVnx) calculated through CT images and/or MRI were documented. All patients were scheduled to follow up. Results: The pre-treatment plasma EBV DNA concentration was significantly associated with primary tumor volume (Spearman correlation coefficient=0.614; P=0.000). With a cutoff value of 20,000 copies/ml and 0 copies/ml respectively for pre-treatment and post-treatment plasma EBV DNA copy number, patients with lower EBV DNA concentrations had statistically preferable progression-free survival,metastasis-free survival and overall survival compared with those with higher EBV DNA concentrations. Cox regression analysis demonstrated that both pre-treatment EBV DNA load (P=0.050;RR=3.95) and post-treatment EBV DNA load (P=0.001;RR=11.74) were risk factors for metastasis-free survival. When further integrating pre-treatment with post-treatment concentration of EBV DNA, it was demonstrated that whether EBV DNA concentration could be dropped to 0 after treatment dominate the prognostic effect for metastasis-free survival (P=0.000). Conclusions: Pre- and post-treatment plasma EBV DNA have different clinical significance. Pre-treatment plasma EBV DNA is a reliable molecular marker reflecting primary tumor volume. While the clearance of circulating plasma EBV DNA after treatment is a good predictive marker of freedom from distant metastasis.

No significant financial relationships to disclose.