Faculty Bibliography

Lipoproteins are natural nanoparticles composed of phospholipids and apolipoproteins that transport lipids throughout the body. As key effectors of lipid homeostasis, the functions of lipoproteins have been demonstrated to be crucial during the development of cardiovascular diseases. Therefore various strategies have been used to study their biology and detect them in vivo. A recent approach has been the production of lipoprotein biomimetic particles loaded with diagnostically active nanocrystals in their core. These include, but are not limited to: quantum dots, iron oxide or gold nanocrystals. Inclusion of these nanocrystals enables the utilization of lipoproteins as probes for a variety of imaging modalities (computed tomography, magnetic resonance imaging, fluorescence) while preserving their biological activity. Furthermore as some lipoproteins naturally accumulate in atherosclerotic plaque or specific tumor tissues, nanocrystal core lipoprotein biomimetics have been developed as contrast agents for early diagnosis of these diseases.

What dictates the prevalence of certain types of breast cancer, which are classified by markers, particularly estrogen receptor (ER), expression profiles such as basal or luminal, and genetic alterations such as HER2 amplification, in particular populations is not well understood. It is increasingly evident that microenvironment disruption is highly intertwined with cancer progression. Here, the idea that microenvironment shapes the course of carcinogenesis, and hence breast cancer subtype, is discussed. Aggressive, basal-like, ER-negative breast tumors occur in younger women, African-American women, women who carry BRCA1 mutation, and women exposed to ionizing radiation. Recent experimental studies using ionizing radiation, a well-documented environmental exposure, suggest that certain processes in the microenvironment strongly favor the development of ER-negative tumors. Understanding the contribution of tissue microenvironment during carcinogenesis could lead to prevention strategies that are personalized to age, agent, and exposure to reduce the risk of aggressive breast cancer. Clin Cancer Res; 19(3); 541-8. (c)2012 AACR.

BACKGROUND: Targeted therapies in renal cell carcinoma can have different effects on primary and metastatic tumors. To pave the way for predictive biomarker development, we assessed differences in expression of targets of currently approved drugs in matched primary and metastatic specimens from 34 patients. METHODS: Four cores from each site were embedded in tissue microarray blocks. Expression of B-Raf, C-Raf, cKIT, FGF-R1, HIF-2alpha, mTOR, PDGF-Rbeta, VEGF-R1, VEGF-R2, VEGF-R3, VEGF, VEGF-B, VEGF-C, VEGF-D, MEK1, and ERK1/2 was studied using a quantitative immunofluorescence method. RESULTS: No significant differences were observed in global expression levels in primary and metastatic renal cell carcinoma tumors, with the exception of MEK, which had higher expression in metastatic than primary specimens. Similarly, more ki67 positive cells were seen in metastatic specimens. Correlations between marker expression in primary and metastatic specimens were variable, with the lowest correlation seen for FGF-R1 and VEGF-D. There were no significant differences in the degree of heterogeneity in primary versus metastatic tumors. CONCLUSIONS: Expression of most of the studied markers was similar in primary and metastatic renal cell carcinoma tumors, suggesting that predictive biomarker testing for these markers can be conducted on either the primary or metastatic tumors for most markers.

An increasing number of Gram-negative bacteria have been observed to secrete outer membrane vesicles (OMVs). Many mysteries remain with respect to OMV formation, the regulation of OMV content and mode of targeting and fusion. Bacterial OMVs appear to serve a variety of purposes in intra- and interspecies microbial extracellular activities. OMVs have been shown to mediate cell-to-cell exchange of DNA, protein and small signalling molecules. The impact of such material exchanges on microbial communities and pathogenic processes, including the delivery of toxins at high concentration through OMVs, is discussed. This rather recent aspect of microbial ecology is likely to remain an important area of research as an in-depth understanding of OMVs may allow new approaches for combating bacterial infections and provide new routes for selective drug delivery.

It is well known that TNFalpha play an important role in wear debris induced inflammatory osteolysis, which is a major cause of periprosthetic loosening. We previously reported that Progranulin (PGRN) antagonized TNFalpha action via binding to TNF receptors and protected against bone erosion in inflammatory arthritis (Tang W, et al, Science, 2011). The goal of this study is to determine whether PGRN plays a protective role in titanium particle induced inflammatory osteolysis. To do so, we took advantage of both in vitro RAW647.3 cells and two in vivo well-accepted mice models. Ti particle dramatically induced expression of endogenous PGRN in RAW647.3 cell and in the mice models. In addition, recombinant PGRN attenuated Ti particle induced inflammation and inflammatory osteolysis in RAW647.3 cell, calvaria explant and mice models, as the elevation of inflammatory biomarkers were significantly impaired, osteoclastogenesis was suppressed and bone erosion of calvaria was protected by PGRN. Furthermore, recombinant PGRN repressed activation of NF-B signaling pathway by Ti particle. Collectively, PGRN is a novel molecule that inhibits Ti particle induced inflammation, probably through interacting with TNF-alpha/NF-B signaling pathways. These findings not only provide novel insights into the role of PGRN in Ti particle induced inflammation reaction, but may also lead to the development of novel therapeutic intervention strategies for periprosthetic loosening

Mebendazole (MBZ) was identified as a promising therapeutic on the basis of its ability to induce apoptosis in melanoma cell lines through a B-cell lymphoma 2 (BCL2)-dependent mechanism. We now show that in a human xenograft melanoma model, oral MBZ is as effective as the current standard of care temozolomide in reducing tumor growth. Inhibition of melanoma growth in vivo is accompanied by phosphorylation of BCL2 and decreased levels of X-linked inhibitor of apoptosis (XIAP). Reduced expression of XIAP on treatment with MBZ is partially mediated by its proteasomal degradation. Furthermore, exposure of melanoma cells to MBZ promotes the interaction of SMAC/DIABLO with XIAP, thereby alleviating XIAP's inhibition on apoptosis. XIAP expression on exposure to MBZ is indicative of sensitivity to MBZ as MBZ-resistant cells do not show reduced levels of XIAP after treatment. Resistance to MBZ can be reversed partially by siRNA knockdown of cellular levels of XIAP. Our data indicate that MBZ is a promising antimelanoma agent on the basis of its effects on key antiapoptotic proteins.

Progranulin (PGRN) is a multifunctional growth factor which is composed of seven-and-a-half repeats of a cysteine-rich motif in the order P-G-F-B-A-C-D-E. We previously reported that PGRN directly bound to TNF-alpha receptors (TNFR), and inhibited TNF-alpha activity (Tang, W, et al, Science. 2011). Atsttrin, an engineered protein composed of three PGRN fragments (1/2F-1/2A-1/2C), exhibited selective TNFR binding, and potently prevented inflammation in multiple arthritis mouse models (Tang, W, et al, Science. 2011). It is well established that TNF family ligands bind to receptors in a heterohexameric 3:3 complex. We created a novel engineering protein, Atsttrin primer, which comprised the same fragments as Atsttrin but in a different sequence (1/2A-1/2C-1/2F). The purpose of this study is to determine (1) whether the three fragments of Atsttrin (i.e. 1/2A, 1/2C and 1/2F) act independently for interacting with TNFR; and if so, (2) whether Atsttrin primer is able to block the binding of TNF-alpha to TNFR, and has therapeutic effect in inflammatory arthritis, as does Atsttrin. Molecular mechanistic studies through Yeast-two hybrid screening and Solid-phase binding assay revealed that Atsttrin primer had stronger binding affinity to TNFR compared with Atsttrin, and effectively inhibited TNF-alpha from binding to TNFRs. To define the role of Atsttrin primer in inflammatory arthritis, we induced collagen-induced-arthritis (CIA) model in

Introduction: Portal/mesenteric vein resection (PVR) is technically challenging and adds potential morbidity to a pancreaticoduodenectomy (PD). We reviewed our experience with PD for pancreatic adenocarcinoma to evaluate both short and long term outcomes following PVR. Methods: From our institutional pancreatic adenocarcinoma database, we identified 223 patients who underwent pancreaticoduodenectomy (PD) with (Group I n= 20) or without (Group II n= 203) PVR during the period 1990-2011. The study end-points were overall morbidity, 30-day mortality, length of post-operative stay (LOS), overall survival (OS). Differences between groups were evaluated using t-test or chi-squared test. OS for each group was estimated with Kaplan-Meier method and compared using the log-rank statistics. Results: The two groups were similar in terms of gender, age, ethnicity, underlying comorbidities and performance status (see table 1). One patient in Group I and 8 in Group II were deemed borderline resectable (5.0% vs. 3.9%, p = 0.8) and underwent neo-adjuvant treatment. Duration of surgery was longer in Group I (532 vs. 456 min, p = 0.04), but there were no differences in operative blood losses (1047 vs. 991 ml, p = 0.8), length of stay (13.9 vs. 14.4 days, p = 0.8), overall morbidity (55% vs. 38%, p = 0.14). There were only 2 post-operative deaths, both in the Group II (p = 0.7). Pathology revealed similar TNM stage and rates of resections with negative margins (85% vs. 75%, p = 0.8). At median follow-up of 14 months there was no significant difference in OS (20.5 vs. 15.8 months, p = 0.6) Conclusions: In our experience, post-operative and long-term outcomes were not adversely affected by PVR. PVR should be offered to patients with pancreatic cancer involving portal or mesenteric veins. (Table Presented)

Myelinated axons are organized into specialized domains critical to their function in saltatory conduction, i.e., nodes, paranodes, juxtaparanodes, and internodes. Here, we describe the distribution and role of the 4.1B protein in this organization. 4.1B is expressed by neurons, and at lower levels by Schwann cells, which also robustly express 4.1G. Immunofluorescence and immuno-EM demonstrates 4.1B is expressed subjacent to the axon membrane in all domains except the nodes. Mice deficient in 4.1B have preserved paranodes, based on marker staining and EM in contrast to the juxtaparanodes, which are substantially affected in both the PNS and CNS. The juxtaparanodal defect is evident in developing and adult nerves and is neuron-autonomous based on myelinating cocultures in which wt Schwann cells were grown with 4.1B-deficient neurons. Despite the juxtaparanodal defect, nerve conduction velocity is unaffected. Preservation of paranodal markers in 4.1B deficient mice is associated with, but not dependent on an increase of 4.1R at the axonal paranodes. Loss of 4.1B in the axon is also associated with reduced levels of the internodal proteins, Necl-1 and Necl-2, and of alpha-2 spectrin. Mutant nerves are modestly hypermyelinated and have increased numbers of Schmidt-Lanterman incisures, increased expression of 4.1G, and express a residual, truncated isoform of 4.1B. These results demonstrate that 4.1B is a key cytoskeletal scaffold for axonal adhesion molecules expressed in the juxtaparanodal and internodal domains that unexpectedly regulates myelin sheath thickness. (c) 2012 Wiley Periodicals, Inc.

Alterations in the metabolic control of lipid and glucose homeostasis predispose an individual to develop cardiometabolic diseases, such as type 2-diabetes mellitus and atherosclerosis. Work over the last years has suggested that microRNAs (miRNAs) play an important role in regulating these physiological processes. The contribution of miRNAs in regulating metabolism is exemplified by miR-33, an intronic miRNA encoded in the Srebp genes. miR-33 controls cellular cholesterol export and fatty acid degradation, whereas its host genes stimulate cholesterol and fatty acid synthesis. Other miRNAs, such as miR-122, also play a critical role in regulating lipid homeostasis by controlling cholesterol synthesis and lipoprotein secretion in the liver. This review article summarizes the recent findings in the field, highlighting the contribution of miRNAs in regulating lipid and glucose metabolism. We will also discuss how the modulation of specific miRNAs may be a promising strategy to treat metabolic diseases.