Reactive Oxygen Species (ROS)-Assisted Nano-Therapeutics Surface-Decorated with Epidermal Growth Factor Fragments for Enhanced Wound Healing

In this study, stimuli-responsive liberation of an epidermal growth factor fragment (EGFfr) is accomplished using nanofibrous meshes to improve wound healing effects. Electrospun nanofibers are fragmented by mechanical milling, followed by aminolysis to fabricate powdered nanofibrils (NFs). EGFfrs are covalently immobilized on NFs via thioketal linkers (EGFfr@TK@NF) for reactive oxygen species (ROS)-dependent liberation. EGFfr@TK@NF exhibits ROS-responsive liberation of EGFfr from the matrix at hydrogen peroxide (H2 O2 ) concentrations of 0-250 mm. Released EGFfr is confirmed to enhance the migration of HaCaT cell monolayers, and keratinocytic gene expression levels are significantly enhanced when H2 O2 is added to obtain the released fraction of NFs. An in vivo study on the dorsal wounds of mice reveals that EGFfr-immobilized NFs improve the expression levels of keratin1, 5, and 14 for 2 weeks when H2 O2 is added to the wound sites, suggesting that the wounded skin is re-epithelized with the original epidermis. Thus, EGFfrs-immobilized NFs are anticipated to be potential nanotherapeutics for wound treatment in combination with the conventional disinfection process with H2 O2 .

Improving mental health following multiple disasters in Australia: a randomized controlled trial of the Skills for Life Adjustment and Resilience (SOLAR) programme

Background: The mental health impacts of climate change-related disasters are significant. However, access to mental health services is often limited by the availability of trained clinicians. Although building local community capability for the mental health response is often prioritised in policy settings, the lack of evidence-based programs is problematic. The aim of this study was to test the efficacy of the Skills for Life Adjustment and Resilience programme (SOLAR) delivered by trained local community members following compound disasters (drought, wildfires, pandemic-related lockdowns) in Australia.Method: Thirty-six community members were trained to deliver the SOLAR programme, a skills-based, trauma informed, psychosocial programme. Sixty-six people with anxiety, depression and/or posttraumatic stress symptoms, and impairment were randomised into the SOLAR programme or a Self-Help condition. They were assessed pre, post and two months following the interventions. The SOLAR programme was delivered across five 1-hourly sessions (either face to face or virtually). Those in the Self-Help condition received weekly emails with self-help information including links to online educational videos.Results: Multigroup analyses indicated that participants in the SOLAR condition experienced significantly lower levels of anxiety and depression, and PTSD symptom severity between pre - and post-intervention (T1 to T2), relative to the Self-Help condition, while controlling for scores at intake. These differences were not statistically different at follow-up. The SOLAR programme was associated with large effect size improvements in posttraumatic stress symptoms over time.Conclusion: The SOLAR programme was effective in improving anxiety, depression and posttraumatic stress symptoms over time. However, by follow-up the size of the effect was similar to an active self-help condition. Given the ongoing stressors in the community associated with compounding disasters it may be that booster sessions would have been useful to sustain programme impact.Trial registration: Australian New Zealand Clinical Trials Registry identifier: ACTRN12621000283875..

Abstract 6156: MALT1 protease inhibition overcomes BTK inhibitor resistance and shows synergistic activity with venetoclax in models of B cell lymphoma and leukemia

Introduction: Specific B cell malignancies, including CLL and the aggressive non-GCB subtype of DLBCL, are driven by constitutive activation of the B cell receptor (BCR) pathway and the transcription factor NF-κB. Pharmacological inhibition of MALT1 protease, a key mediator of the BCR/NF-κB signal transduction pathway, may therefore provide an attractive treatment option for patients with these cancers. Further, as combination therapy is often required for the treatment of aggressive B cell malignancies, the identification of therapies that synergistically combine with MALT1 inhibitors could afford additional and promising treatment options.

Experimental Procedures: A highly potent and orally bioavailable MALT1 protease inhibitor (ABBV-MALT1) was used to test the hypothesis that MALT1 inhibition will abrogate the proliferation of preclinical models of B cell malignancies in vitro and in vivo. Tumors treated with ABBV-MALT1 were subjected to transcriptomic and functional proteomic assays to elucidate molecular mechanisms of action and rational combination partners.

Results: Mechanistic studies reveal that ABBV-MALT1 effectively inhibits signal transduction of the BCR pathway and reduces NF-κB gene activation in non-GCB DLBCL cell lines resulting in cell cycle arrest and diminished viability. In vivo, oral administration of this compound demonstrates robust tumor growth inhibition in several models of B cell tumors, including non-GCB DLBCL models that are resistant to Bruton’s tyrosine kinase (BTK) inhibitors. NF-κB target genes include the pro-survival family members BCL-XL and BCL2-A1, which aid in regulation of the intrinsic apoptosis pathway. As ABBV-MALT1-induced inhibition of the NF-κB pathway resulted in downregulation of these genes, we hypothesized that the associated tumor models would become increasingly dependent on the pro-survival family member BCL-2. To test this hypothesis, combination studies of ABBV-MALT1 and the selective BCL-2 inhibitor venetoclax were performed in both cell line and patient-derived xenograft models of DLBCL. Herein we show that concomitant administration of ABBV-MALT1 and venetoclax results in dramatic antitumor activity in all models tested in vivo. This efficacy also translates to primary patient CLL cells in vitro where the combination confers greater levels of apoptosis compared to either agent alone.

Conclusion: ABBV-MALT1 demonstrates robust single agent anti-tumor activity in malignant B cell models that are resistant to BTK inhibitors. Moreover, combination of ABBV-MALT1 with the BCL-2 inhibitor venetoclax shows synergistic cell killing of B cell tumors in vitro and dramatic tumor regression in vivo. Together, these data indicate that MALT1 inhibition may overcome BTK inhibitor resistance and combine with venetoclax to effectively treat patients with B cell malignancies.

Citation Format: Joshua P. Plotnik, Raghuveer S. Mali, Velitchka Bontcheva, Colleen Dowell, Jun Chen, Adam E. Richardson, Ryan A. McClure, Paul Jung, Lan Pham, Andrew J. Souers, Jonathan A. Meulbroek, William N. Pappano. MALT1 protease inhibition overcomes BTK inhibitor resistance and shows synergistic activity with venetoclax in models of B cell lymphoma and leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6156.

Mortality prediction and long-term outcomes for civilian cerebral gunshot wounds: A decision-tree algorithm based on a single trauma center

Gunshot wounds (GSW) are one of the most lethal forms of head trauma. The lack of clear guidelines for civilian GSW complicates surgical management. We aimed to develop a decision-tree algorithm for mortality prediction and report long-term outcomes on survivors based on 15-year data from our level 1 trauma center. We retrospectively reviewed 96 consecutive patients who presented with cerebral GSWs between 2003 and 2018. Clinical information from our trauma database, EMR, and relevant imaging scans was reviewed. A decision-tree model was constructed based on variables showing significant differences between survivors and non-survivors. After excluding patients who died at arrival, 54 patients with radiologically confirmed intracranial injury were included. Compared to survivors (51.9%), non-survivors (48.1%) were significantly more likely to have perforating (entry and exit wound), as opposed to penetrating (entry wound only), injuries. Bi-hemispheric and posterior fossa involvement, cerebral herniation, and intraventricular hemorrhage were more commonly present in non-survivors. Based on the decision-tree, Glasgow Coma Scale (GCS) > 8 and penetrating, uni-hemispheric injury predicted survival. Among patients with GCS ≤ 8 and normal pupillary response, lack of 1) posterior fossa involvement, 2) cerebral herniation, 3) bi-hemispheric injury, and 4) intraventricular hemorrhage, were associated with survival. Favorable long-term outcomes (mean follow-up 34.4 months) were possible for survivors who required neurosurgery and stable patients who were conservatively managed. We applied clinical and radiological characteristics that predicted survival to construct a decision-tree to facilitate surgical decision-making for GSW. Further validation of the algorithm in a large patient setting is recommended.

Venous thromboembolism in IBD: Increased risk for women in CD?

Although coagulation disturbances have been described in inflammatory bowel disease (IBD), it remains unclear how common venous thromboembolism (VTE) is in IBD, and what factors influence VTE frequency. We evaluated VTE in Crohn's disease (CD) and ulcerative colitis (UC) at LSUHSC-S, a southern US medical center with an approximately equal White: African-American (AA) (1.12:1) patient base. This retrospective study evaluated VTE as a co-morbidity in IBD as a function of age, gender and race based on ICD-10 coding (2011-2015.) Results. Of 276 IBD diagnostic records, 213 were for CD (77.17%) and 63 for UC (22.8%). 52% of the CD patients were white, 42% were AA, and 6% were other. 42% of CD patients were male, with 58% were female. 6.1% (13 patients) of the 213 CD patients had a VTE. Of these 13 CD patients, 9 had active disease and 4 were in remission. 9 of 13 were female and 4 were male, with 5 white patients and 4 A A patients. 63 patients were diagnosed with UC, 3.38-fold fewer cases than CD. 25 UC patients were white, 25 were AA and 13 were in other ethnic groups. Of 63 UC cases, 2 UC patients had a VTE, both with active disease. At our institution, VTE appears to be 3x more frequently associated with CD than UC and was more common in white female patients. The recognition of VTE risk in CD, particularly in women, may be an important observation which may guide therapy and limit potentially life-threatening consequences.

Trends in General Anesthesia Utilization by Board-Certified Pediatric Dentists

PURPOSE

The purpose of this study was to explore the trends and utilization of general anesthesia services among board-certified pediatric dentists practicing in the United States.

METHODS

A 26 item survey was sent to 4,216 board-certified pediatric dentists by REDCap or mail. Results were tabulated, and trends were analyzed.

RESULTS

A response rate of 31.8 percent was obtained. All American Academy of Pediatric Dentistry districts were represented proportionally. Most respondents (87 percent) reported using general anesthesia (GA) in their practices. Those who used GA, 50.4 percent reported using a hospital setting, and 60.5 percent used a physician anesthesiologist. Endotracheal intubation was the most common (88.5 percent) method of anesthesia delivery. Most diplomates (62.6 percent) favored dental anesthesiology as a recognized specialty by the American Dental Association.

CONCLUSIONS

The majority of American Board of Pediatric Dentistry diplomates used general anesthesia in their practice. The preferred modality of delivery is oral/nasal intubation, with most services provided by physician anesthesiologists in a hospital/ambulatory setting. Physician anesthesiologists are inclined to provide care in a hospital-based setting. Dentist anesthesiologists provided care in the dental office. Most respondents support dental anesthesiology as a recognized specialty of the American Dental Association.

Brain injury results in lower levels of melatonin receptors subtypes MT1 and MT2

BACKGROUND

Traumatic brain injury (TBI) is a devastating and costly acquired condition that affects individuals of all ages, races, and geographies via a number of mechanisms. The effects of TBI on melatonin receptors remain unknown.

PURPOSE

The purpose of this study is to explore whether endogenous changes in two melatonin receptor subtypes (MT1 and MT2) occur after experimental TBI.

SAMPLE

A total of 25 adult male Sprague Dawley rats were used with 6 or 7 rats per group.

METHODS

Rats were randomly assigned to receive either TBI modeled using controlled cortical impact or sham surgery and to be sacrificed at either 6- or 24-h post-operatively. Brains were harvested, dissected, and flash frozen until whole cell lysates were prepared, and the supernatant fluid aliquoted and used for western blotting. Primary antibodies were used to probe for melatonin receptors (MT1 and MT2), and beta actin, used for a loading control. ImageJ and Image Lab software were used to quantify the data which was analyzed using t-tests to compare means.

RESULTS

Melatonin receptor levels were reduced in a brain region- and time point- dependent manner. Both MT1 and MT2 were reduced in the frontal cortex at 24h and in the hippocampus at both 6h and 24h.

DISCUSSION

MT1 and MT2 are less abundant after injury, which may alter response to MEL therapy. Studies characterizing MT1 and MT2 after TBI are needed, including exploration of the time course and regional patterns, replication in diverse samples, and use of additional variables, especially sleep-related outcomes.

CONCLUSION

TBI in rats resulted in lower levels of MT1 and MT2; replication of these findings is necessary as is evaluation of the consequences of lower receptor levels.

B-Cell Lymphoma Patient-Derived Xenograft Models Enable Drug Discovery and Are a Platform for Personalized Therapy

Purpose: Patients with B-cell lymphomas often relapse after frontline therapy, and novel therapies are urgently needed to provide long-term remission. We established B-cell lymphoma patient-derived xenograft (PDX) models to assess their ability to mimic tumor biology and to identify B-cell lymphoma patient treatment options.Experimental Design: We established the PDX models from 16 patients with diffuse large B-cell lymphoma, mantle cell lymphoma, follicular lymphoma, marginal zone lymphoma, or Burkitt lymphoma by inoculating the patient tumor cells into a human bone chip implanted into mice. We subjected the PDX models to histopathologic and phenotypical examination, sequencing, and drug efficacy analysis. Primary and acquired resistance to ibrutinib, an oral covalent inhibitor of Bruton tyrosine kinase, were investigated to elucidate the mechanisms underlying ibrutinib resistance and to identify drug treatments to overcome resistance.Results: The PDXs maintained the same biological, histopathologic, and immunophenotypical features, retained similar genetic mutations, and produced comparable drug responses with the original patient tumors. In the acquired ibrutinib-resistant PDXs, PLC-γ2, p65, and Src were downregulated; however, a PI3K signaling pathway member was upregulated. Inactivation of the PI3K pathway with the inhibitor idelalisib in combination with ibrutinib significantly inhibited the growth of the ibrutinib-resistant tumors. Furthermore, we used a PDX model derived from a clinically ibrutinib-relapsed patient to evaluate various therapeutic choices, ultimately eliminating the tumor cells in the patient's peripheral blood.Conclusions: Our results demonstrate that the B-cell lymphoma PDX model is an effective system to predict and personalize therapies and address therapeutic resistance in B-cell lymphoma patients. Clin Cancer Res; 23(15); 4212-23. ©2017 AACR.

Animal models in genomic research: Techniques, applications, and roles for nurses

Animal research has been conducted by scientists for over two millennia resulting in a better understanding of human anatomy, physiology, and pathology, as well as testing of novel therapies. In the molecular genomic era, pre-clinical models represent a key tool for understanding the genomic underpinnings of health and disease and are relevant to precision medicine initiatives. Nurses contribute to improved health by collecting and translating evidence from clinically relevant pre-clinical models. Using animal models, nurses can ask questions that would not be feasible or ethical to address in humans, and establish the safety and efficacy of interventions before translating them to clinical trials. Two advantages of using pre-clinical models are reduced variability between test subjects and the opportunity for precisely controlled experimental exposures. Standardized care controls the effects of diet and environment, while the availability of inbred strains significantly reduces the confounding effects of genetic differences. Outside the laboratory, nurses can contribute to the approval and oversight of animal studies, as well as translation to clinical trials and, ultimately, patient care. This review is intended as a primer on the use of animal models to advance nursing science; specifically, the paper discusses the utility of preclinical models for studying the pathophysiologic and genomic contributors to health and disease, testing interventions, and evaluating effects of environmental exposures. Considerations specifically geared to nurse researchers are also introduced, including discussion of how to choose an appropriate model and controls, potential confounders, as well as legal and ethical concerns. Finally, roles for nurse clinicians in pre-clinical research are also highlighted.

Abstract B18: B-cell lymphoma patient-derived xenograft models: The road to personalized therapy

Lymphoma is the most common hematological malignancy, and B-cell lymphoma accounts for 85% of all lymphomas. The current overall cure rate for B-cell lymphoma is estimated at ~30%, even with the development and application of novel therapies, and the majority of patients relapse after treatment due to the development of drug resistance. The evaluation of novel drug targets using established B-cell lymphoma cell lines is limited by the inexact correlation between responsiveness observed in the cell line versus the patient sample. However, patient-derived xenograft (PDX) mouse models have been shown to recapitulate the diversity of growth, metastasis, and histopathology of the original tumor, overcoming the limitations of cell lines. Furthermore, recent studies have indicated that PDXs can recapitulate treatment responses of the parental tumor and can successfully choose a therapeutic target and regimen for the patient. We previously established a SCID-hu in vivo human primary mantle cell lymphoma (MCL) PDX model, the first human primary MCL animal model for biological and therapeutic research, and investigated the disease biology and potential novel human MCL therapies using this model. In this MCL PDX model, the engraftment and growth of patient MCL cells were dependent on the human bone marrow microenvironment supplied by an implanted human fetal bone chip. Our clinical information and reports show that numerous B-cell lymphoma subtypes involve bone marrow; therefore, we expanded our PDX model to include various B-cell lymphomas to study the clonal evolution of tumors and to evaluate novel therapies for the treatments of these diseases. PDX models (n=20) were established for multiple different types of B-cell lymphoma, including MCL (n=12), Burkitt's lymphoma (n=1), marginal zone lymphoma (n=2), follicular lymphoma (n=2), chronic lymphocytic leukemia (n=1) and diffuse large B-cell lymphoma (n=2). The engraftment rate was high at 95%, the tumor xenografts rapidly grew at 3-4 weeks/generation, and 68% of the tumor xenografts were passaged for multiple generations, even up to 14 generations. Further demonstrating the utility of this model to recapitulate the characteristics of the original patient tumor, the tumor xenograft cells migrated to the lymph nodes, spleen, bone marrow, and gastrointestinal tract of the host mice, mimicking the disease progression observed in humans, and H&E staining showed similar histological features between the original patient tumor and the tumor xenograft cells such as splenomegaly. To identify novel targeted treatments for these various lymphomas, we assessed the in vitro cell viability of MCL, DLBCL, and Burkitt's lymphoma cells from the patients and isolated from the PDXs of different generations. The responses to these agents were very similar between the PDXs and the original patient tumor, and the treatment responses were the same between different generations, showing that the PDX models recapitulate the drug response of the original tumor. Finally, in 34% of relapsed/refractory MCL patients who were treated with ibrutinib, transient lymphocytosis was observed, and this phenomenon was also observed in our MCL PDX mouse models treated with ibrutinib. Furthermore, the combination of ibrutinib and rituximab quenched lymphocytosis in the animal model, which provided the basis of using this combination in a clinical trial in which the MCL patients had an overall response rate of 88%. In conclusion, these data demonstrate the ability of PDX mouse models to successfully recapitulate and the characteristics of the original patient tumor as well as mimic the progression of the disease in vivo. In addition, the drug responses of the original patient tumor to various agents were similar to the responses of the tumor xenograft, demonstrating that these PDX models can be used as a way to personalize the treatment of numerous types of B-cell lymphomas.

Citation Format: Leo Zhang, Lan Pham, Hui Zhang, Jingmeng Xie, Wenjing Tao, Taylor Bell, Zhihong Chen, Bingliang Fang, Michael Wang, Krystle Nomie. B-cell lymphoma patient-derived xenograft models: The road to personalized therapy. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B18.

Minimally Invasive Lumbar Pedicle Screw Fixation Using Cortical Bone Trajectory - A Prospective Cohort Study on Postoperative Pain Outcomes

Objective: Our study aims to evaluate the clinical outcomes of cortical screws in regards to postoperative pain.

Background: Pedicle screw fixation is the current mainstay technique for posterior spinal fusion. Over the past decade, a new technique called cortical screw fixation has been developed, which allows for medialized screw placement through stronger cortical bone. There have been several studies that showed either biomechanical equivalence or superiority of cortical screws. However, there is currently only a single study in the literature looking at clinical outcomes of cortical screw fixation in patients who have had no prior spine surgery.

Methods: We prospectively looked at the senior author’s patients who underwent cortical versus pedicle lumbar screw fixation surgeries between 2013 and 2015 for lumbar degenerative disease. Eighteen patients underwent cortical screw fixation, and 15 patients underwent traditional pedicle screw fixation. We looked at immediate postoperative pain, changes in short-term pain (six to 12 weeks post-surgery), and changes in long-term pain (six to eight months). All pain outcomes were measured using a visual analog scale ranging from 1 to 10. Mann-Whitney or Kruskal-Wallis tests were used to measure continuous data, and the Fisher Exact test was used to measure categorical data as appropriate.

Results: Our results showed that the cortical screw cohort showed a trend towards having less peak postoperative pain (p = 0.09). The average postoperative pain was similar between the two cohorts (p = 0.93). There was also no difference in pain six to 12 weeks after surgery (p = 0.8). However, at six to eight months, the cortical screw cohort had worse pain compared to the pedicle screw cohort (p = 0.02).

Conclusions: The cortical screw patients showed a trend towards less peak pain in the short-term (one to three days post-surgery) and more pain in the long-term (six to eight months post-surgery) compared to pedicle screw patients. Both cohorts had a statistically significant reduction in pain levels compared to preoperative pain. More studies are needed to further evaluate postoperative pain, long-term functional outcomes, and fusion rates in patients who undergo cortical screw fixation.

Abstract 4391: Overcoming primary ibrutinib resistance in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare and incurable subtype of B-cell lymphoma. In a phase II study of ibrutinib in MCL patients, most of the patients responded and had long durable remissions; however, 22.7% of patients were considered to be non-responsive to ibrutinib, and an additional 22/110 patients displayed initial positive responses to ibrutinib but also experienced disease progression within 12 months of treatment, with both responses classified as primary ibrutinib resistant. Therefore, understanding the mechanisms mediating primary ibrutinib resistance may identify new prognostic and predictive markers and potential therapeutic targets.

Bruton's tyrosine kinase (BTK) plays an important role in B-cell development, activation, and differentiation. Upon B-cell receptor (BCR) activation, BTK is phosphorylated and activated by SYK. Phosphoinositide 3-kinase (PI3K) is recruited to the BCR, and the induction of these signaling activities leads to the downstream activation of multiple effector proteins, including nuclear factor-kB (NF-kB), AKT, RAS, mTOR and mitogen-activated protein kinase (MAPK). BTK and PI3K have been shown to function independently to mediate BCR signaling, suggesting that PI3K signaling activities may underlie ibrutinib resistance independently of BTK. PI3K has also been associated with primary ibrutinib resistance. To further elucidate the mechanisms underlying ibrutinib resistance, we conferred primary ibrutinib resistance using both MCL cell lines and MCL-bearing patient-derived xenograft (PDX) mouse models and used whole exome sequencing (WES) and reverse phase protein analysis (RPPA) to identify any genetic and expression changes associated with primary ibrutinib resistance. WES did not reveal any mutations in BTK or within the proximal BCR pathway, consistent with WES data on primary ibrutinib resistant MCL cases. RPPA analysis showed a significant increase in the PI3K/AKT/mTOR/MCL-1 compensatory pathway component levels in ibrutinib-resistant cell lines when compared with their parental cells as well as ibrutinib-resistant PDXs. To determine whether inhibiting these pathways would overcome primary ibrutinib resistance, we tested various therapeutic combinations targeting these pathways. Ibrutinib plus the PI3K inhibitor idelalisib, the AKT inhibitor ACP-319, the mTOR inhibitors AZD8055 or BEZ235 as well as the proteasome inhibitor carfilzomib inhibited tumor growth in vitro and in vivo in the PDX mouse models, demonstrating that targeting these alternative pathways may overcome ibrutinib resistance. This work strongly suggests that targeting the PI3K/AKT/mTOR/MCL-1 compensatory pathway successfully inhibits the viability of ibrutinib-resistant MCL tumor cells both in vitro and in vivo and identified potential therapies that can be used to treat ibrutinib-resistant patients in clinical practice.

Citation Format: Leo Zhang, Lan Pham, Hui Zhang, Jingmeng Xie, Wenjing Tao, Taylor Bell, Zhihong Chen, Krystle Nomie, Bingliang Fang, Michael Wang. Overcoming primary ibrutinib resistance in mantle cell lymphoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4391.

Dysregulated CXCR4 expression promotes lymphoma cell survival and independently predicts disease progression in germinal center B-cell-like diffuse large B-cell lymphoma

Abnormal expression of the chemokine receptor CXCR4 plays an essential role in tumor cell dissemination and disease progression. However, the significance of CXCR4 overexpression in de novo diffuse large B cell lymphoma (DLBCL) is unknown. In 743 patients with de novo diffuse large B cell lymphoma (DLBCL) who received standard Rituximab-CHOP immunochemotherapy, we assessed the expression of CXCR4 and dissected its prognostic significance in various DLBCL subsets. Our results showed that CXCR4⁺ patients was associated with male, bulky tumor, high Ki-67 index, activated B-cell-like (ABC) subtype, and Myc, Bcl-2 or p53 overexpression. Moreover, CXCR4⁺ was an independent factor predicting poorer progression-free survival in germinal-center B-cell-like (GCB)-DLBCL, but not in ABC-DLBCL; and in patients with an IPI of ≤2, but not in those with an IPI>2. The lack of prognostic significance of CXCR4 in ABC-DLBCL was likely due to the activation of p53 tumor suppressor attenuating CXCR4 signaling. Furthermore, concurrent CXCR4⁺ and BCL2 translocation showed dismal outcomes resembling but independent of MYC/BCL2 double-hit DLBCL. Gene expression profiling suggested that alterations in the tumor microenvironment and immune responses, increased tumor proliferation and survival, and the dissemination of CXCR4⁺ tumor cells to distant organs or tissues were underlying molecular mechanisms responsible for the CXCR4⁺ associated poor prognosis.

Bone morphogenetic proteins signal via SMAD and mitogen-activated protein (MAP) kinase pathways at distinct times during osteoclastogenesis

To investigate the role of bone morphogenetic protein (BMP) signaling in osteoclastogenesis in vivo, we eliminated BMPRII in osteoclasts by creating a BMPRII(fl/fl);lysM-Cre mouse strain. Conditional knock-out (cKO) mice are osteopetrotic when compared with WT controls due to a decrease in osteoclast activity. Bone marrow macrophages (BMMs) isolated from cKO mice are severely inhibited in their capacity to differentiate into mature osteoclasts in the presence of M-CSF and receptor activator of NF-κB (RANK) ligand. We also show that BMP noncanonical (MAPK) and canonical (SMAD) pathways are utilized at different stages of osteoclast differentiation. BMP2 induces p38 phosphorylation in pre-fusion osteoclasts and increases SMAD phosphorylation around osteoclast precursor fusion. Phosphorylation of MAPKs was decreased in differentiated BMMs from cKO animals. Treating BMMs with the SMAD inhibitor dorsomorphin confirms the requirement for the canonical pathway around the time of fusion. These results demonstrate the requirement for BMP signaling in osteoclasts for proper bone homeostasis and also explore the complex signaling mechanisms employed by BMP signaling during osteoclast differentiation.

Glycosylation of Twisted Gastrulation is Required for BMP Binding and Activity during Craniofacial Development

Twisted gastrulation (TWSG1) is a conserved, secreted glycoprotein that modulates signaling of bone morphogenetic proteins (BMPs) in the extracellular space. Deletion of exon 4 of mouse Twsg1 (mTwsg1) is associated with significant craniofacial defects. However, little is understood about the biochemical properties of the corresponding region of the protein. We have uncovered a significant role for exon 4 sequences as encoding the only two glycosylation sites of the mTWSG1 protein. Deletion of the entire exon 4 or mutation of both glycosylation sites within exon 4 abolishes glycosylation of mTWSG1. Importantly, we find that constructs with mutated glycosylation sites have significantly reduced BMP binding activity. We further show that glycosylation and activity of TWSG1 recombinant proteins vary markedly by cellular source. Non-glycosylated mTWSG1 made in E. coli has both reduced affinity for BMPs, as shown by surface plasmon resonance analysis, and reduced BMP inhibitory activity in a mandibular explant culture system compared to glycosylated proteins made in insect cells or murine myeloma cells. This study highlights an essential role for glycosylation in Twisted gastrulation action.

Bone morphogenetic protein 2 signaling in osteoclasts is negatively regulated by the BMP antagonist, twisted gastrulation

Bone morphogenetic proteins (BMPs) have been shown to regulate both osteoblasts and osteoclasts. We previously reported that BMP2 could directly enhance RANKL-mediated osteoclast differentiation by increasing the size and number of osteoclasts. Similarly, genetic deletion of the BMP antagonist Twisted gastrulation (TWSG1) in mice, resulted in an enhancement of osteoclast formation, activity and osteopenia. This was accompanied by increased levels of phosphorylated Smad (pSmad) 1/5/8 in Twsg1(-/-) osteoclasts in vitro. The purpose of this study was to develop an adenoviral vector overexpressing Twsg1 as a means of inhibiting osteoclast activity. We demonstrate that overexpressing TWSG1 in primary osteoclasts decreased the size and number of multinuclear TRAP-positive osteoclasts, expression of osteoclast genes, and resorption ability. Overexpression of TWSG1 did not affect osteoclast proliferation or apoptosis. However, overexpression of TWSG1 decreased the levels of pSmad 1/5/8 in osteoclasts. Addition of exogenous BMP2 to osteoclasts overexpressing TWSG1 rescued the size and levels of pSmad 1/5/8 compared to cultures infected with a control virus. Finally, TWSG1 overexpression in osteoclasts isolated from the Twsg1(-/-) mice rescued size of the osteoclasts while further addition of exogenous BMP2 reversed the effect of TWSG1 overexpression and increased the size of the osteoclasts similar to control virus infected cells. Taken together, we demonstrate that overexpressing TWSG1 in osteoclasts via an adenoviral vector results in inhibition of osteoclastogenesis and may provide a potential therapy for inhibiting osteoclast activity in a localized manner.

Abstract 306: Development of EC-DG as a molecular theranostic personalized medicine

Purpose: D-glucosamine has been reported to inhibit proliferation of cancer cells in culture and in vivo. We have then synthesized Tc-99m- ethylenedicysteine-glucosamine (EC-DG). We found Tc-99m-EC-DG was involved in cell proliferation in lung, breast and head and neck cultures and could assess breast cancer treatment outcome in vivo by planar scintigraphy. Tc-99m-EC-DG is a safe imaging agent in lung cancer patients. This study was amied to (1) assess a novel response to unlabeled rhenium-EC-DG (Re-EC-DG) involving the translation regulation of hypoxia inducible factor (HIF)-1alpha expression in lymphoma cells, and, (2) evaluate feasibility of using EC-DG for theranostic approaches in cancers.

Methods: For theranostic assessment studies, we synthesized cold Re-EC-DG. Re-EC-DG was synthesized via a two-step synthesis. The first step was to synthesize Re-EC by reacting rheniumoxo trichloride with EC. The second step was to react Re-EC with D-glucosamine tetraacetate, followed by de-acetylation. Twelve types of DLBCL cells were incubated with Re-EC-DG at various concentrations (0-10 mM) and TUNEL assays were used to determine cell apoptosis. To ascertain the mechanism of the anticancer properties for Re-EC-DG, DLBCL-LY10 cells were treated with Re-EC-DG (0-5 mM) for 48 hrs. Immunoblotting were then performed on nuclear extracts with 50 µg. For radiotheranostic assessment studies, 13762 breast tumor-bearing rats were imaged with In-111-EC-DG and tumor/muscle ratios were determined at 0.5-24 hrs. Radiation absorbed dose was estimated for the use of Y-90-EC-DG.

Results: There was a dose response relationship of Re-EC-DG inhibition in DLBCL cells. Extensive apoptosis was observed at 24 hrs in lymphoma cell cultures. Re-EC-DG showed significant tumorcidal activity compared to normal B-lymphocyte activity at doses >0.17 µmol. Re-EC-DG caused a decreased expression of HIF-1alpha under normoxic conditions in DLBCL-LY10 cells. Tumor-to-muscle ratios for In-111-EC-DG were 5.43±0.45 to 7.80±0.05 whereas In-111-EC had 3.24±0.32 to 4.64±0.16 at 0.5-24 hrs. Radiation exposure of In-111-EC-DG to whole body, blood-forming organs, gonads, and effective dose equivalent for a single dose at 5 mCi was below the limits of 3 rad annually and 5 rad total. The absorbed dose in all other organs was below the limits of 5 rad annually and 15 rad total.

Conclusion: EC-DG is a useful molecular theranostic compound. In-111-EC-DG has favorable dosimetry, providing a potential use of Y-90-EC-DG to treat cancers. Re-EC-DG inhibits HIF-1alpha expression and is an attractive anti-proliferation compound.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 306. doi:10.1158/1538-7445.AM2011-306

HDAC3 and HDAC7 have opposite effects on osteoclast differentiation

Histone deacetylases (HDACs) are negative regulators of transcription. Endochondral bone formation including chondrocyte and osteoblast maturation is regulated by HDACs. Very little is known about the role HDACs play in osteoclast differentiation. It has been previously reported that HDAC inhibitors, trichostatin A and sodium butyrate, suppress osteoclast differentiation through multiple mechanisms. In this study, we report that suppression of HDAC3 expression similar to HDAC inhibitors inhibits osteoclast differentiation, whereas osteoclasts suppressed for HDAC7 expression had accelerated differentiation when compared with control cells. Mitf, a transcription factor, is necessary for osteoclast differentiation. We demonstrate that Mitf and HDAC7 interact in RAW 264 cells and osteoclasts. The transcriptional activity of Mitf is repressed by HDAC7. Lastly, we show that either the amino or the carboxyl terminus of HDAC7 is sufficient for transcriptional repression and that the repression of HDAC7 is insensitive to trichostatin A, indicating that HDAC7 represses Mitf at least in part by deacetylation-independent mechanism.

Involvement of toll-like receptor 4 in alveolar bone loss and glucose homeostasis in experimental periodontitis

BACKGROUND AND OBJECTIVE

There is general agreement that certain fatty acids and lipopolysaccharides (LPS) promote inflammation through toll-like receptor 4 (TLR4), and that inflammation promotes insulin resistance. We therefore hypothesized that mice with periodontitis and a TLR4 loss-of-function (LOF) mutation fed a high-fat (HF) diet would develop improved glucose homeostasis compared with wild-type (WT) animals with periodontitis fed a HF diet.

MATERIAL AND METHODS

Wild-type and TLR4 mutant mice fed a HF diet were divided into four groups (n = 6/group): WT; WT with periodontitis (WT/P); mutant (Mut); and mutant with periodontitis (Mut/P). Periodontitis was induced by placing LPS soaked ligatures around maxillary second molars. Fasting insulin and glucose levels were measured weekly for 10 wk. Glucose tolerance was evaluated at baseline (week 1) and at 9 wk. Insulin signaling (phosphorylation of Akt) and tumor necrosis factor-α (TNF-α) mRNA levels in liver were determined when the mice were killed at week 10.

RESULTS

Mut/P mice developed less alveolar bone loss compared with WT/P mice (p < 0.05). Fasting glucose levels were improved after 8 wk of feeding a HF diet (weeks 9 and 10) in Mut/P mice compared with Mut, WT and WT/P mice (p < 0.05). Glucose tolerance was impaired in all groups compared with baseline (p < 0.05), except for the Mut/P group. Insulin signaling was improved (p < 0.05), and expression of TNF-α was decreased (p < 0.05) in the liver of Mut/P mice compared with the liver of WT/P mice.

CONCLUSION

The TLR4 LOF mutation partially protects against alveolar bone loss and improves glucose homeostasis in mice with periodontitis fed a HF diet.

Bone morphogenic protein 2 directly enhances differentiation of murine osteoclast precursors

Previous studies found that bone morphogenic proteins (BMPs) support osteoclast formation, but it is not clear whether this is a direct effect on osteoclasts or mediated indirectly through osteoblasts. We have shown that a mouse deficient for the BMP antagonist Twisted gastrulation suggested a direct positive role for BMPs on osteoclastogenesis. In this report, we further determine the significance of BMP signaling on osteoclast formation in vitro. We find that BMP2 synergizes with suboptimal levels of receptor activator of NF-kappaB ligand (RANKL) to enhance in vitro differentiation of osteoclast-like cells. The enhancement by BMP2 is not a result of changes in the rate of proliferation or survival of the bone marrow-derived cultures, but is accompanied by an increase in expression of genes involved in osteoclast differentiation and fusion. Treatment with BMP2 did not significantly alter expression of RANKL or OPG in our osteoclast cultures, suggesting that the enhancement of osteoclastogenesis is not mediated indirectly through osteoblasts or stromal cells. Consistent with this, we detected phosphorylated SMAD1,5,8 (p-SMAD) in the nuclei of mononuclear and multinucleated cells in osteoclast cultures. Levels of p-SMAD, BMP2, and BMP receptors increased during differentiation. RNAi suppression of Type II BMP receptor inhibited RANKL-stimulated formation of multinuclear TRAP-positive cells. The BMP antagonist noggin inhibited RANKL-mediated osteoclast differentiation when added prior to day 3, while addition of noggin on day 3 or later failed to inhibit their differentiation. Taken together, these data indicate that osteoclasts express BMP2 and BMP receptors, and that autocrine BMP signaling directly promotes the differentiation of osteoclasts-like cells.

Intracisternal administration of glibenclamide or 5-hydroxydecanoate does not reverse the neuroprotective effect of ketogenic diet against ischemic brain injury-induced neurodegeneration

PRIMARY OBJECTIVE

To investigate the role of ATP-sensitive potassium (K(ATP)) channels in the neuroprotective effects of a ketogenic diet against cardiac arrest-induced cerebral ischemic brain injury-induced neurodegeneration.

RESEARCH DESIGN

Male Sprague Dawley rats were randomly divided into three groups and were fed with a ketogenic diet for 25 days before being subjected to a cardiac arrest-induced cerebral ischemia for 8 minutes 30 seconds. Four hours before cardiac arrest-induced cerebral ischemia, one group was intracisternally injected with glibenclamide, a plasma membrane K(ATP) channel blocker. The second group was injected with 5-hydroxydecanoate, a mitochondrial K(ATP) channel blocker. The third group was without the pre-treatment with K(ATP) channel antagonist. Nine days after the cardiac arrest, rats were sacrificed. Fluoro-jade (FJ) staining was used to evaluate cerebral ischemic neurodegeneration in the rat brain sections.

MAIN OUTCOMES AND RESULTS

The number of FJ-positive degenerating neurons in the CA1 area of the hippocampus, the cerebellum and the thalamic reticular nucleus of the ketogenic diet-fed rats with or without glibenclamide or 5-hydroxydecanoate pre-treatment before cardiac arrest-induced cerebral ischemia is zero.

CONCLUSIONS

The results suggest that K(ATP) channels do not play a significant role in the neuroprotective effects of the ketogenic diet against cardiac arrest-induced cerebral ischemic injury-induced neurodegeneration.

Discovery and structure-activity relationship of 3-methoxy-N-(3-(1-methyl-1H-pyrazol-5-yl)-4-(2-morpholinoethoxy)phenyl)benzamide (APD791): a highly selective 5-hydroxytryptamine2A receptor inverse agonist for the treatment of arterial thrombosis

Serotonin, which is stored in platelets and is released during thrombosis, activates platelets via the 5-HT(2A) receptor. 5-HT(2A) receptor inverse agonists thus represent a potential new class of antithrombotic agents. Our medicinal program began with known compounds that displayed binding affinity for the recombinant 5-HT(2A) receptor, but which had poor activity when tested in human plasma platelet inhibition assays. We herein describe a series of phenyl pyrazole inverse agonists optimized for selectivity, aqueous solubility, antiplatelet activity, low hERG activity, and good pharmacokinetic properties, resulting in the discovery of 10k (APD791). 10k inhibited serotonin-amplified human platelet aggregation with an IC(50) = 8.7 nM and had negligible binding affinity for the closely related 5-HT(2B) and 5-HT(2C) receptors. 10k was orally bioavailable in rats, dogs, and monkeys and had an acceptable safety profile. As a result, 10k was selected further evaluation and advanced into clinical development as a potential treatment for arterial thrombosis.

Tenofovir treatment of primary osteoblasts alters gene expression profiles: implications for bone mineral density loss

There is strong clinical evidence that implicates tenofovir in the loss of bone mineral density during treatment of human immunodeficiency virus infection. In this study, we sought to test the hypothesis that tenofovir treatment of osteoblasts causes changes in the gene expression profile that would impact osteoblast function during bone formation. Primary osteoblasts were isolated and then treated with the tenofovir prodrug, tenofovir disoproxil fumarate (TDF). Total RNA from TDF-treated and untreated osteoblasts were extracted and used for microarray analysis to assess TDF-associated changes in the gene expression profile. Strikingly, the changes in gene expression profiles involved in cell signaling, cell cycle and amino acid metabolism, which would likely impact osteoblast function in bone formation. Our findings demonstrate for the first time that tenofovir treatment of primary osteoblasts results in gene expression changes that implicate loss of osteoblast function in tenofovir-associated bone mineral density loss.

Tenofovir-associated bone density loss

Clinical observations have revealed a strong correlation between loss of bone density in HIV-infected individuals, particularly in conjunction with the antiretroviral drug tenofovir, a nucleotide analog that inhibits HIV reverse transcriptase. The most compelling correlations have been observed in clinical studies involving young children and adolescents. These observations strongly suggest that bone density is being affected during active bone growth and development, implicating a role for tenofovir in bone loss. Here we discuss the literature and potential mechanisms for how tenofovir-associated bone loss may arise, which likely involves perturbation of cellular DNA synthesis and gene expression. Elucidation of the mechanism(s) involved in tenofovir-mediated bone loss will help in developing adjuvant therapies to reduce tenofovir-associated bone density loss.

Downregulation of Gnas, Got2 and Snord32a following tenofovir exposure of primary osteoclasts

Clinical observations have implicated the antiretroviral drug tenofovir with bone density loss during the management of HIV infection. The goal of this study was to investigate the in vitro effects of tenofovir exposure of primary osteoclasts in order to gain insights into the potential mechanisms for the drug-induced bone density loss. We hypothesized that tenofovir may alter the expression of key genes involved in osteoclast function. To test this, primary osteoclasts were exposed to physiologically relevant concentrations of the prodrug tenofovir disoproxil fumarate (TDF), then intensive microarray analysis was done to compare tenofovir-treated versus untreated cells. Specific downregulation of Gnas, Got2 and Snord32a were observed in the TDF-treated cells. The functions of these genes help to explain the basis for tenofovir-associated bone density loss. Our studies represent the first analysis of the effects of tenofovir on osteoclast gene expression and help to explain the basis of tenofovir-associated bone density loss in HIV-infected individuals.

Spinal cord injury causes rapid osteoclastic resorption and growth plate abnormalities in growing rats (SCI-induced bone loss in growing rats)

Spinal cord injury causes severe bone loss. We report osteoclast resorption with severe trabecular and cortical bone loss, decreased bone mineral apposition, and growth plate abnormalities in a rodent model of contusion spinal cord injury. These findings will help elucidate the mechanisms of osteoporosis following neurological trauma.

INTRODUCTION

Limited understanding of the mechanism(s) that underlie spinal cord injury (SCI)-induced bone loss has led to few treatment options. As SCI-induced osteoporosis carries significant morbidity and can worsen already profound disability, there is an urgency to advance knowledge regarding this pathophysiology.

METHODS

A clinically relevant contusion model of experimental spinal cord injury was used to generate severe lower thoracic SCI by weight-drop (10 g x 50 mm) in adolescent male Sprague-Dawley rats. Body weight and gender-matched naïve (no surgery) rats served as controls. Bone microarchitecture was determined by micro-computed tomographic imaging. Mature osteoclasts were identified by TRAP staining and bone apposition rate was determined by dynamic histomorphometry.

RESULTS

At 10 days post-injury we detected a marked 48% decrease in trabecular bone and a 35% decrease in cortical bone at the distal femoral metaphysis by micro-CT. A 330% increase in the number of mature osteoclasts was detected at the growth plate in the injured animals that corresponded with cellular disorganization at the chondro-osseous junction. Appositional growth studies demonstrated decreased new bone formation with a mineralization defect indicative of osteoblast dysfunction.

CONCLUSIONS

Contusion SCI results in a rapid bone loss that is the result of increased bone resorption and decreased bone formation.

Alcohol and malt liquor availability and promotion and homicide in inner cities

We investigated the role of the alcohol environment in explaining disparities in homicide rates among minorities in 10 cities in the United States using 2003 data from the Malt Liquor and Homicide study. We hypothesized that (a) higher concentrations of African Americans would be associated with higher homicide rates, as well as higher alcohol and malt liquor availability and promotion, and (b) the relationship between neighborhood racial/ethnic concentration and homicide would be attenuated by the greater alcohol and malt liquor availability and promotion in African American neighborhoods. Hypotheses were tested using separate Poisson, linear, and logistic regression models that corrected for spatial autocorrelation. Census block groups served as the unit of analysis (n = 450). We found that higher concentrations of African Americans were associated with higher homicide rates as well as greater alcohol availability, especially malt liquor availability. The promotion of malt liquor on storefronts was also significantly greater in African American than in other neighborhoods. However, none of the measures representing alcohol or malt liquor availability and promotion variables changed the effect of neighborhood racial/ethnic concentration on homicide. Limitations and implications of our findings are discussed.

NHA-oc/NHA2: a mitochondrial cation-proton antiporter selectively expressed in osteoclasts

Bone resorption is regulated by a complex system of hormones and cytokines that cause osteoblasts/stromal cells and lymphocytes to produce factors including RANKL, that ultimately result in the differentiation and activation of osteoclasts, the bone resorbing cells. We used a microarray approach to identify genes upregulated in RANKL-stimulated osteoclast precursor cells. Osteoclast expression was confirmed by multiple tissue Northern and in situ hybridization analysis. Gene function studies were carried out by siRNA analysis. We identified a novel gene, which we termed nha-oc/NHA2, which is strongly upregulated during RANKL-induced osteoclast differentiation in vitro and in vivo. nha-oc/NHA2 encodes a novel cation-proton antiporter (CPA) and is the mouse orthologue of a human gene identified in a database search: HsNHA2. nha-oc/NHA2 is selectively expressed in osteoclasts. NHA-oc/NHA2 protein localizes to the mitochondria, where it mediates Na(+)-dependent changes in mitochondrial pH and Na(+) acetate induced mitochondrial passive swelling. RNA silencing of nha-oc/nha2 reduces osteoclast differentiation and resorption, suggesting a role for NHA-oc/NHA2 in these processes. nha-oc/NHA2 therefore is a novel member of the CPA family and is the first mitochondrial NHA characterized to date. nha-oc/NHA2 is also unique in that it is the first eukaryotic and tissue-specific CPA2 characterized to date. NHA-oc/NHA2 displays the expected activities of a bona fide CPA and plays a key role(s) in normal osteoclast differentiation and function.

Prostanoids induce egr1 gene expression in cementoblastic OCCM cells

BACKGROUND AND OBJECTIVE

Prostanoids that activate protein kinase C signaling are potent anabolic stimulators of cementoblastic OCCM cells. Using cDNA subtractive hybridization, we identified early growth response gene-1 (egr1) as a prostanoid-induced gene. Egr1, a zinc-finger transcription factor expressed during tooth development, regulates cell growth and differentiation. We hypothesize that Egr1 may mediate part of the prostanoid-induced anabolic effect in cementoblasts. Our objective was to characterize prostanoid-induced egr1 gene expression in OCCM cells.

MATERIAL AND METHODS

Total RNA and proteins were assayed by northern blot and western immunoblot assays.

RESULTS

Prostaglandin E2-, prostaglandin F2alpha- and fluprostenol-induced egr1 mRNA levels peaked at 0.5 h and returned to baseline by 4 h. Prostaglandin F2alpha and fluprostenol more potently induced egr1 compared with prostaglandin E2. The phorbol ester, phorbol 12-myristate 13-acetate, which activates protein kinase C signaling, induced egr1 mRNA levels 66-fold over the control, whereas forskolin (a cAMP-protein kinase A activator) and ionomycin (a calcium activator) had no effect. Protein kinase C inhibition significantly inhibited prostaglandin E2-, prostaglandin F2alpha- and fluprostenol-induced egr1 mRNA levels. Finally, prostanoids maximally induced Egr1 protein at 1 h.

CONCLUSION

egr1 is a primary response gene induced by prostaglandin E2, prostaglandin F2alpha and fluprostenol in OCCM cells through protein kinase C signaling, suggesting that Egr1 may be a key mediator of anabolic responses in cementoblasts. Cementum is vital for periodontal organ maintenance and regeneration. Periodontal ligament fibers (Sharpey's fibers) insert into bone and cementum, thereby supporting the tooth in the alveolus (1). If the periodontal organ is lost, its regeneration requires cementoblast differentiation in order to form new cementum for periodontal ligament fiber insertion. Early attempts to regenerate cementum have proven difficult and rarely generate sufficient tissue (2). A better understanding of the molecular and cellular regulators that promote cementoblast differentiation is critical for developing targeted periodontal regeneration.

Expression analysis of nha-oc/NHA2: a novel gene selectively expressed in osteoclasts

Bone resorption by osteoclasts is required for normal bone remodeling and reshaping of growing bones. Excessive resorption is an important pathologic feature of many diseases, including osteoporosis, arthritis, and periodontitis [Abu-Amer, Y. (2005). Advances in osteoclast differentiation and function. Curr. Drug Targets. Immune. Endocr. Metabol. Disord. 5, 347-355]. On the other hand, deficient resorption leads to osteopetrosis which is characterized by increased bone mass and may lead to bone deformities or in severe cases to death [Blair, H.C., Athanasou, N.A. 2004. Recent advances in osteoclast biology and pathological bone ddresorption. Histol. Histopathol. 19, 189-199; Del Fattore, A., Peruzzi, B., Rucci, N., Recchia, I., Cappariello, A., Longo, M., Fortunati, D., Ballanti, P., Iacobini, M., Luciani, M., Devito, R., Pinto, R., Caniglia, M., Lanino, E., Messina, C., Cesaro, S., Letizia, C., Bianchini, G., Fryssira, H., Grabowski, P., Shaw, N., Bishop, N., Hughes, D., Kapur, R.P., Datta, H.K., Taranta, A., Fornari, R., Migliaccio, S., and Teti, A. 2006. Clinical, genetic, and cellular analysis of 49 osteopetrotic patients: implications for diagnosis and treatment. J. Med. Genet. 43, 315--325]. Recently, we identified a gene, nha-oc/NHA2, which is strongly up regulated during RANKL-induced osteoclast differentiation in vitro and in vivo. nha-oc/NHA2 encodes a novel cation/proton exchanger that is strongly expressed in osteoclasts. The purpose of this work was to further validate the restricted expression of nha-oc/NHA2 in osteoclasts by in situ hybridization. Our results showed that nha-oc is expressed predominantly in bone. In the head, expression was found in the supraoccipitale bone, calvarium, mandible, and maxilla. Furthermore, nha-oc positive cells co-express the osteoclast markers TRAP and cathepsin k, confirming nha-oc/NHA2 osteoclast localization. However, only a subset of cathepsin k-expressing cells is positive for nha-oc/NHA2, suggesting that nha-oc is expressed by terminally differentiated osteoclasts.

Roles for negative cell regulator 14-3-3sigma in control of MDM2 activities

The 14-3-3sigma, upregulated by p53 in response to DNA damage, can have a positive-feedback impact driving p53 activities and is a human cancer epithelial marker downregulated in various tumors. However, the precise roles of 14-3-3sigma during tumorigenesis are not well characterized. Here, we show that 14-3-3sigma is a critical regulator of murine double minute oncogene (MDM2). 14-3-3sigma interacts with MDM2 at the RING domain. The C-terminal region of 14-3-3sigma binds to MDM2 very efficiently. Importantly, 14-3-3sigma overexpression leads to destabilization of MDM2 through enhancing MDM2 self-ubiquitination and accelerating turnover rate. Conversely, loss of 14-3-3sigma results in a significant increase in MDM2 protein. Moreover, live-cell images indicated that 14-3-3sigma can affect the location of MDM2 from the nucleus to the cytoplasm, and that MDM2-mediated cytoplasmic localization of p53 can be reversed by the presence of 14-3-3sigma. Significantly, we further showed that 14-3-3sigma causes MDM2 downregulation, thereby stabilizing p53 and inhibiting tumor growth in animal tumors. Also, 14-3-3sigma blocks MDM2-mediated retinoblastoma degradation and p53 NEDDylation. Our results provide evidence that 14-3-3sigma is a pivotal MDM2 regulator involved in blocking a variety of activities of MDM2.

Tricritical phenomena at the gamma-->alpha transition in Ce0.9-xLaxTh0.1 alloys

The gamma-->alpha isostructural transition in the Ce0.9-xLaxTh0.1 system is measured as a function of La alloying using specific heat, magnetic susceptibility, resistivity, thermal expansivity or striction measurements. A line of discontinuous transitions, as indicated by the change in volume, decreases exponentially from 118 K to close to 0 K with increasing La doping, and the transition changes from being first-order to continuous at a critical concentration, x(c) approximately 0.14. At the tricritical point, the coefficient of the linear T term in the specific heat gamma and the magnetic susceptibility increase rapidly near x(c) and approach large values at x=0.35 signifying that a heavy Fermi-liquid state evolves at large doping. The Wilson ratio reaches a value above 2 for a narrow range of concentrations near x(c), where the specific heat and susceptibility vary most rapidly with the doping concentration.

Seroprevalence and risk factors of syphilis infection in pregnant women delivering at Harare Maternity Hospital, Zimbabwe

OBJECTIVE

To evaluate risk factors and outcomes of syphilis during pregnancy.

DESIGN

Hospital based, cross sectional study.

SETTING

Harare Maternity Hospital, Harare, Zimbabwe.

SUBJECTS

A random sample of 2 969 pregnant women.

MAIN OUTCOME MEASURES

Syphilis seroprevalence.

RESULTS

Of the 2 969 women who provided blood samples, 4.8% were RPR positive. Approximately 2.2% of study subjects were RPR positive and TPHA negative. Notably, 2.5% of the population was RPR and TPHA positive at the time of giving birth. Older women had a higher risk of having positive syphilis status (p = 0.057). Increases in parity and gravidity were significantly associated with increased risk of syphilis infection. Prior stillbirths were associated with an increased risk of syphilis infection (odds ratio [OR], 3.4; 95% CI, 1.61 to 7.37; p = 0.001). Syphilis positive mothers were significantly more likely to give birth to syphilis positive newborns (p < 0.0001).

CONCLUSIONS

Our results suggest that there should be more effective antenatal screening and treatment of syphilis in Harare. Syphilis affects many sub-Saharan countries where effective educational outreach, screening, and treatment should take place to prevent the transmission of this venereal disease, especially among reproductive age and pregnant women.

The proteasome inhibitor PS-341 inhibits growth and induces apoptosis in Bcr/Abl-positive cell lines sensitive and resistant to imatinib mesylate

BACKGROUND AND OBJECTIVES

Imatinib mesylate (IM) is the choice treatment for Bcr/Abl-positive malignancies. Emergence of resistance to IM warrants the exploration of novel well-tolerated anticancer agents. We intended to evaluate the effect of PS-341 on proliferation, survival, and cellular events in Bcr/Abl-positive cells sensitive and resistant to IM, and to investigate the effect of PS-341 and IM in conjunction.

DESIGN AND METHODS

Bcr/Abl-positive cell lines sensitive (p210Bcr/Abl KBM5, p210Bcr/Abl KBM7, and p190Bcr/Abl Z-119) or resistant (KBM5-R) to IM were treated with PS-341 alone or in combination with IM. The effect on cell growth was determined using the MTT assay. Cell-cycle analysis was performed by propidium iodide staining. Apoptosis was evaluated by measurement of sub-G1 DNA content, annexin V binding, and caspase 3 activity assays. Levels of apoptotic proteins, P-IkBalpha, Bcr/Abl, and phosphorylated Bcr/Abl were determined by western blotting. NF-kappaB activity was evaluated by electromobility gel shift assays.

RESULTS

PS-341 exerted growth inhibition effects in IM-sensitive and -resistant cells. This phenomenon correlated with accumulation of cells in the G2/M phase of cell cycle; transient downregulation of NFkappaB DNA binding activity; downregulation of Bcl-xL; activation of caspase 3, induction of apoptosis; inhibition of expression and phosphorylation of Bcr/Abl. Sequential combination of PS-341 followed by IM demonstrated a synergistic pro-apoptotic effect in IM-sensitive cells; concomitant exposure was antagonistic.

INTERPRETATION AND CONCLUSIONS

PS-341 suppresses growth and induces apoptosis in Bcr/Abl-positive cells sensitive and resistant to IM. The use of PS-341 should be explored in patients with chronic myelogenous leukemia resistant to IM. Trials of combinations of PS-341 and IM require cautious design.