Xanthones from mangosteen extracts as natural chemopreventive agents: potential anticancer drugs

Despite decades of research, the treatment and management of malignant tumors still remain a formidable challenge for public health. New strategies for cancer treatment are being developed, and one of the most promising treatment strategies involves the application of chemopreventive agents. The search for novel and effective cancer chemopreventive agents has led to the identification of various naturally occurring compounds. Xanthones, from the pericarp, whole fruit, heartwood, and leaf of mangosteen (Garcinia mangostana Linn., GML), are known to possess a wide spectrum of pharmacologic properties, including antioxidant, anti- tumor, anti-allergic, anti-inflammatory, anti-bacterial, anti-fungal, and anti-viral activities. The potential chemopreventive and chemotherapeutic activities of xanthones have been demonstrated in different stages of carcinogenesis (initiation, promotion, and progression) and are known to control cell division and growth, apoptosis, inflammation, and metastasis. Multiple lines of evidence from numerous in vitro and in vivo studies have confirmed that xanthones inhibit proliferation of a wide range of human tumor cell types by modulating various targets and signaling transduction pathways. Here we provide a concise and comprehensive review of preclinical data and assess the observed anticancer effects of xanthones, supporting its remarkable potential as an anticancer agent.

Periodontal tissue engineering with stem cells from the periodontal ligament of human retained deciduous teeth

BACKGROUND AND OBJECTIVE

Periodontal ligament stem cells from human permanent teeth (PePDLSCs) have been investigated extensively in periodontal tissue engineering and regeneration. However, little knowledge is available on the periodontal ligament stem cells from human retained deciduous teeth (DePDLSCs). This study evaluated the potential of DePDLSCs in periodontal tissue regeneration.

MATERIAL AND METHODS

DePDLSCs were isolated and purified by limited dilution. The characteristics of DePDLSCs were evaluated and compared with PePDLSCs both in vitro and in vivo.

RESULTS

DePDLSCs presented a higher proliferation rate and colony-forming capacity than PePDLSCs in vitro. During the osteogenic induction, alkaline phosphatase (ALP) activity, mineralized matrix formation and expression of mineralization-related genes, including runt-related transcription factor 2 (RUNX2), ALP, collagen type I (COLI) and osteocalcin (OCN) were significantly enhanced in DePDLSCs compared with PePDLSCs. Furthermore, DePDLSC cell sheets showed a stronger synthesis of collagen type I in the extracellular matrix than did PePDLSC cell sheets. After in vivo transplantation, DePDLSC cell sheets recombined with human dentin blocks were able to generate new cementum/periodontal ligament-like tissues.

CONCLUSION

Our findings suggest that DePDLSCs can be used as a promising candidate for periodontal tissue engineering.

Defects in room-temperature ferromagnetic Cu-doped ZnO films probed by x-ray absorption spectroscopy

We report a comprehensive study of the defects in room-temperature ferromagnetic (RTFM) Cu-doped ZnO thin films using x-ray absorption spectroscopy. The films are doped with 2 at.% Cu, and are prepared by reactive magnetron sputtering (RMS) and pulsed laser deposition (PLD), respectively. The results reveal unambiguously that atomic point defects exist in these RTFM thin films. The valence states of the Cu ions in both films are 2(+). In the film prepared by PLD, the oxygen vacancies (V(O)) form around both Zn ions and Cu ions in the hexagonal wurtzite structure. Upon annealing of the film in O(2), the V(O) population reduces and so does the RTFM. In the film prepared by RMS, the V(O)s around Cu ions are not detected, and the V(O) population around Zn ions is also smaller than in the PLD-prepared film. However, zinc vacancies (V(Zn)) are evidenced. Given the low doping level of spin-carrying Cu ions, these results provide strong support for defect-mediated ferromagnetism in Cu-doped ZnO thin films.

Genome-wide analysis of immunophilin FKBP genes and expression patterns in Zea mays

The receptors for the immunosuppression drugs FK506 and rapamycin are called FKBPs (FK506-binding proteins). FKBPs comprise a large family; they are found in many species, including bacteria, fungi, animals, and plants. As a class of peptidyl-prolyl cis-trans isomerase enzymes, the FKBP genes have been the focus of recent studies on plant stress tolerance and immunology. We identified and analyzed gene families encoding these proteins in maize using computational and molecular biology approaches. Thirty genes were found to encode putative FKBPs according to their FK506-binding domain. The FKBP genes can be classified into single domain and multiple domain members based on the number of the domains. By analysis of the physical locations, the 30 FKBP genes were found to be widely distributed on 10 chromosomes. After analysis of the FKBP phylogenetic tree in the maize genome, we found that the 30 genes revealed two major clades. Gene duplication played a major role in the evolution of FKBP genes, which suggests that the FKBP genes in maize have a pattern significantly different from that of these genes in rice. Based on semi-quantitative RT-PCR, we found that the 30 FKBPs were expressed differently in various tissues in maize, which suggests that FKBP genes play different roles in each tissue. Several FKBPs were expressed at higher levels in roots, indicating that these genes in maize may have similar or overlapping functions.

Genome-wide identification, classification, and analysis of two-component signal system genes in maize

Cytokinins play many vital roles in plant development and physiology. In plants, cytokinin signals are sensed and transduced by the two-component signal system. This signaling cascade is typically composed of three proteins: a sensory histidine kinase, a histidine phosphotransfer protein, and a response regulator. Through a comprehensive genome-wide analysis of the maize (Zea mays) genome, 48 genes were identified, including 11 ZmHKs, 9 ZmHPs, and 28 ZmRRs (21 A-type ZmRRs and 7 B-type ZmRRs). Using maize genome sequence databases, we analyzed conserved protein motifs and established phylogenetic relationships based on gene structure, homology, and chromosomal location. The duplication of these two-component system genes in the maize genome corresponded to the clusters of these genes in the phylogenetic trees. Sequence analysis of the duplicate genes demonstrated that one gene may be in gene duplication, and that there was significant variation in the evolutionary history of the different gene families. We assessed the expression levels of all ZmRRs in the leaves and roots by reverse transcription PCR; they were all found to be active. Our results provide a foundation for functional and evolutionary studies on maize two-component signal system proteins.

Pharmacokinetics of the nonnucleoside reverse transcriptase inhibitor efavirenz among HIV-infected Ugandans

BACKGROUND

Pharmacokinetic variability of the nonnucleoside reverse transcriptase inhibitor efavirenz has been documented, and high variation in trough concentrations or clearance has been found to be a risk for virological failure. Africans population exhibits greater variability in efavirenz concentrations than other ethnic groups, and so a better understanding of the pharmacokinetics of the drug is needed in this population. This study characterized efavirenz pharmacokinetics in HIV-infected Ugandans.

METHODS

Efavirenz plasma concentrations were obtained for 66 HIV-infected Ugandans initiating efavirenz- based regimens, with blood samples collected at eight time-points over 24 h on day 1 of treatment, and at a further eight time-points on day 14. Noncompartmental analysis was used to describe the pharmacokinetics of efavirenz.

RESULTS

The mean steady-state minimum plasma concentration (C(min) ) of efavirenz was 2.9 µg/mL, the mean area under the curve (AUC) was 278.5 h µg/mL, and mean efavirenz clearance was 7.4 L/h. Although overall mean clearance did not change over the 2 weeks, 41.9% of participants showed an average 95.8% increase in clearance. On day 14, the maximum concentration (C(max) ) of efavirenz was >4 µg/mL in 96.6% of participants, while C(min) was <1 µg/mL in only 4.5%. Overall, 69% of participants experienced adverse central nervous system (CNS) symptoms attributable to efavirenz during the 2-week period, and 95% of these participants were found to have efavirenz plasma concentrations >4 µg/mL, although only half maintained a high concentration until at least 8 h after dosing.

CONCLUSION

The findings of this study show that HIV-infected patients on efavirenz may exhibit autoinduction to various extents, and this needs to be taken into consideration in the clinical management of individual patients. Efavirenz CNS toxicity during the initial phase of treatment may be related to C(max) , regardless of the sampling time.

The pesticide deltamethrin increases free radical production and promotes nuclear translocation of the stress response transcription factor Nrf2 in rat brain

The transcription factor NF-E2-related factor 2 (Nrf2) plays a critical role in the mammalian response to chemical and oxidative stress through induction of phase II detoxification enzymes and oxidative stress response proteins. We reported that Nrf2 expression was activated by deltamethrin (DM), a prototype of the widely used Parathyroid pesticides, in PC12 cells. However, no study has examined Nrf2 nuclear translocation and free radical production, two hallmarks of oxidative stress, in the mammalian brain in vivo. To this end, we examined translocation of Nrf2 and production of free radicals in rat brain exposed to DM. Indeed, DM initiated nuclear translocation of Nrf2 in a dose-dependent manner. Furthermore, Nrf2 translocation was accompanied by the expression of heme oxygenase-1 gene, an Nrf2-regulated gene linked to free radical production. Deltamethrin exposure promoted free radical formation in rat brain and reactive oxygen species generation in PC12 cells. Translocation of Nrf2 may be a response to DM-dependent induction of free radicals and DM may act as a mammalian neurotoxin by initiating oxidative stress.

Phase I trial of anti-PSMA designer T cells in advanced prostate cancer

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Background: We created chimeric immunoglobulin-T cell receptors (IgTCR) specific for prostate specific membrane antigen (PSMA). When expressed in patient T cells, these “designer T cells” (dTc) specifically kill prostate cancer cells in vitro and in vivo in animal models, with 5/9 (55%) of xenografted mice experiencing complete remissions (Ma et al. Prostate 2004:61:12–25). A phase I clinical trial was approved by the FDA.

Methods: Patient T cells are retrovirally transduced and expanded ex vivo to span dose levels of 10^9 to 10^11 T cells. Patients undergo prior non-myeloablative (NMA) conditioning to create “hematologic space” into which designer T cells are infused for stable engraftment and prolonged in vivo efficacy. Patients are co-administered continuous infusion IL2. Outcomes include Phase Ia goals of safety and Phase Ib goals of establishing an optimal biologic dose in terms of designer T cell engraftment.

Results: Five patients have been treated, three at 10^9 and two at 10^10 cell dose levels. Excellent T cell modifications of 30%-60% were obtained. After NMA conditioning, T cells were infused. Stable engraftments of 1%-20% post-recovery at one month after T cell infusion, thus affirming one of the study end-points. Patients experienced neutropenic fever after conditioning, but no designer T cell-related toxicities. Two patients had partial responses with PSA reductions of 50 and 70% in the two months following treatment with projected benefits of 4 months gain of time to return to starting PSA levels. Results will be updated at the conference.

Conclusions: A new approach to adoptive immune therapy in metastatic prostate cancer has been devised with encouraging early results. Patients are being actively recruited. This clinical trial received partial funding from the US Army/DOD. Preclinical work was supported by the Prostate Cancer Foundation.

No significant financial relationships to disclose.

Dipeptidyl peptidase IV inhibitor sitagliptin reduces local inflammation in adipose tissue and in pancreatic islets of obese mice

Adipose tissue inflammation and reduced pancreatic β-cell function are key issues in the development of cardiovascular disease and progressive metabolic dysfunction in type 2 diabetes mellitus. The aim of this study was to determine the effect of the DPP IV inhibitor sitagliptin on adipose tissue and pancreatic islet inflammation in a diet-induced obesity model. C57Bl/6J mice were placed on a high-fat (60% kcal fat) diet for 12 wk, with or without sitagliptin (4 g/kg) as a food admix. Sitagliptin significantly reduced fasting blood glucose by 21% as well as insulin by ∼25%. Sitagliptin treatment reduced body weight without changes in overall body mass index or in the epididymal and retroperitoneal fat mass. However, sitagliptin treatment led to triple the number of small adipocytes despite reducing the number of the very large adipocytes. Sitagliptin significantly reduced inflammation in the adipose tissue and pancreatic islet. Macrophage infiltration in adipose tissue evaluated by immunostaining for Mac2 was reduced by sitagliptin (P < 0.01), as was the percentage of CD11b+/F4/80+ cells in the stromal vascular fraction (P < 0.02). Sitagliptin also reduced adipocyte mRNA expression of inflammatory genes, including IL-6, TNFα, IL-12(p35), and IL-12(p40), 2.5- to fivefold as well as 12-lipoxygenase protein expression. Pancreatic islets were isolated from animals after treatments. Sitagliptin significantly reduced mRNA expression of the following inflammatory cytokines: MCP-1 (3.3-fold), IL-6 (2-fold), IL-12(p40) (2.2-fold), IL-12(p35) (5-fold, P < 0.01), and IP-10 (2-fold). Collectively, the results indicate that sitagliptin has anti-inflammatory effects in adipose tissue and in pancreatic islets that accompany the insulinotropic effect.

High-energy x-ray backlighter spectrum measurements using calibrated image plates

The x-ray spectrum between 18 and 88 keV generated by a petawatt laser driven x-ray backlighter target was measured using a 12-channel differential filter pair spectrometer. The spectrometer consists of a series of filter pairs on a Ta mask coupled with an x-ray sensitive image plate. A calibration of Fuji™ MS and SR image plates was conducted using a tungsten anode x-ray source and the resulting calibration applied to the design of the Ross pair spectrometer. Additionally, the fade rate and resolution of the image plate system were measured for quantitative radiographic applications. The conversion efficiency of laser energy into silver Kα x rays from a petawatt laser target was measured using the differential filter pair spectrometer and compared to measurements using a single photon counting charge coupled device.

A new uterine compression suture for postpartum haemorrhage with atony

Postpartum haemorrhage (PPH) is a major cause of worldwide maternal mortality and is still associated with significant morbidity. After the B-Lynch suture was reported in 1997, several different uterine compression sutures were found to be successful in controlling PPH. In this paper, we describe another simple variation of the uterine compression suture technique, which was performed without an incision in the uterine wall, without entering the uterine cavity and without suturing the anterior and posterior walls of the uterus together, so minimising the trauma to the uterus. This new uterine compression suture is an effective and safe surgical treatment for PPH caused by atony. It has the potential to apply to intractable PPH after vaginal delivery.