Kristen Picha

Resistin is elevated following traumatic joint injury and causes matrix degradation and release of inflammatory cytokines from articular cartilage in vitro

OBJECTIVE Resistin is a secreted factor that is elevated in rheumatoid arthritis (RA) and believed to drive joint inflammation in vivo. This study was undertaken to determine if resistin is present in the joint following joint injury and to elucidate the role of resistin in cartilage degradation. METHODS The level of resistin was measured in paired synovial fluid (SF) and serum samples from patients following joint injury (anterior cruciate ligament, ACL or meniscus tear). Localization of resistin was visualized by immunohistochemistry of synovial tissue and cartilage from healthy and OA donors. Mouse and human cartilage cultures were used to assess the effect of resistin on cartilage metabolism. RESULTS In trauma patients, resistin levels declined with increasing time post injury. The resistin levels were highest in samples collected up to 1 week following traumatic injury (SF: 2980 pg/ml, serum: 7901 pg/ml) and lowest in samples collected 6-26 years post injury (SF: 686 pg/ml, serum: 5682 pg/ml). Resistin was shown to be expressed in macrophage-like cells in both healthy and OA synovial tissue. Treatment of mouse cartilage cultures with recombinant resistin led to a dose dependent loss of proteoglycan and induction of inflammatory cytokine and PGE(2) production. Recombinant resistin inhibited proteoglycan synthesis in human cartilage explants. CONCLUSION Resistin is elevated both systemically and locally in the weeks immediately following joint injury and has a direct effect on cartilage matrix turnover and cytokine production. Resistin may play a role in the early stages of trauma-induced OA and may represent a new therapeutic target to slow joint destruction in OA.

CNTO 859, a humanized anti-tissue factor monoclonal antibody, is a potent inhibitor of breast cancer metastasis and tumor growth in xenograft models

Thromboembolic complications are frequently associated with advanced cancer. Interestingly, one of the major initiators of blood coagulation, tissue factor (TF), is reported to be overexpressed in several tumor types and can be found on both tumor cells and tumor vasculature. Although the exact mechanisms have yet to be elucidated, TF expressed on tumor cells can trigger intracellular signaling events through various pathways that can lead to tumor angiogenesis, proliferation, and metastasis. There exists preclinical evidence that disruption of TF dependent signaling can effectively inhibit tumor cell migration, metastasis, and angiogenesis. Here, we report for the first time that an antibody to tissue factor can also prevent tumor growth in vivo. Prophylactic administration of CNTO 859, a humanized anti‐human TF antibody, was shown to inhibit experimental lung metastasis of MDA‐MB‐231 human breast carcinoma cells by over 99% compared to a control antibody. Furthermore, therapeutic doses of CNTO 859 were shown to reduce tumor incidence and growth of orthotopically implanted MDA‐MB‐231 cells.

Sensitivity to change of cartilage morphometry using coronal FLASH, sagittal DESS, and coronal MPR DESS protocols - comparative data from the osteoarthritis initiative (OAI)

OBJECTIVE The Osteoarthritis Initiative (OAI) is targeted at identifying sensitive biomarkers and risk factors of symptomatic knee osteoarthritis (OA) onset and progression. Quantitative cartilage imaging in the OAI relies on validated fast low angle shot (FLASH) sequences that suffer from relatively long acquisition times, and on a near-isotropic double echo steady-state (DESS) sequence. We therefore directly compared the sensitivity to cartilage thickness changes and the correlation of these protocols longitudinally. METHODS Baseline (BL) and 12 month follow-up data of 80 knees were acquired using 1.5 mm coronal FLASH and 0.7 mm sagittal DESS (sagDESS) sequences. In these and in 1.5 mm coronal multi-planar reconstructions (MPR) of the DESS the medial femorotibial cartilage was segmented with blinding to acquisition order. In the weight-bearing femoral condyle, a 60% (distance between the trochlear notch and the posterior femur) and a 75% region of interest (ROI) were studied. RESULTS The standardized response mean (SRM = mean change/standard deviation of change) in central medial femorotibial (cMFTC) cartilage thickness was -0.34 for coronal FLASH, -0.37 for coronal MPR DESS, -0.36 for sagDESS with the 60% ROI, and -0.38 for the 75% ROI. Using every second 0.7 mm sagittal slice (DESS) yielded similar SRMs in cMFTC for the 60% and 75% ROI from odd (-0.35/-0.36) and even slice numbers (-0.36/-0.39), respectively. BL cartilage thickness displayed high correlations (r > or = 0.94) between the three protocols; the correlations of longitudinal changes were > or = 0.79 (Pearson) and > or = 0.45 (Spearman). CONCLUSIONS Cartilage morphometry with FLASH and DESS displays similar longitudinal sensitivity to change. Analysis of every second slice of the 0.7 mm DESS provides adequate sensitivity to change.

Rates of change and sensitivity to change in cartilage morphology in healthy knees and in knees with mild, moderate, and end-stage radiographic osteoarthritis: results from 831 participants from the Osteoarthritis Initiative.

To study the longitudinal rate of (and sensitivity to) change of knee cartilage thickness across defined stages of radiographic osteoarthritis (OA), specifically healthy knees and knees with end‐stage radiographic OA.

GLP-1 receptor activation inhibits VLDL production and reverses hepatic steatosis by decreasing hepatic lipogenesis in high-fat-fed APOE*3-Leiden mice.

Objective In addition to improve glucose intolerance, recent studies suggest that glucagon-like peptide-1 (GLP-1) receptor agonism also decreases triglyceride (TG) levels. The aim of this study was to evaluate the effect of GLP-1 receptor agonism on very-low-density lipoprotein (VLDL)-TG production and liver TG metabolism. Experimental Approach The GLP-1 peptide analogues CNTO3649 and exendin-4 were continuously administered subcutaneously to high fat diet-fed APOE*3-Leiden transgenic mice. After 4 weeks, hepatic VLDL production, lipid content, and expression profiles of selected genes involved in lipid metabolism were determined. Results CNTO3649 and exendin-4 reduced fasting plasma glucose (up to −30% and −28% respectively) and insulin (−43% and −65% respectively). In addition, these agents reduced VLDL-TG production (−36% and −54% respectively) and VLDL-apoB production (−36% and −43% respectively), indicating reduced production of VLDL particles rather than reduced lipidation of apoB. Moreover, they markedly decreased hepatic content of TG (−39% and −55% respectively), cholesterol (−30% and −55% respectively), and phospholipids (−23% and −36% respectively), accompanied by down-regulation of expression of genes involved in hepatic lipogenesis (Srebp-1c, Fasn, Dgat1) and apoB synthesis (Apob). Conclusion GLP-1 receptor agonism reduces VLDL production and hepatic steatosis in addition to an improvement of glycemic control. These data suggest that GLP-receptor agonists could reduce hepatic steatosis and ameliorate dyslipidemia in patients with type 2 diabetes mellitus.

Abstract LB-312: Bispecific Centyrin simultaneously targeting EGFR and c-Met demonstrates improved activity compared to the mixture of single agents.

Many tumors compensate with a resistance mechanism once a signaling pathway is inhibited, as evidenced in patients treated with small molecule inhibitors of EGFR which frequently show increased expression of c-Met or HGF. Since both EGFR and c-Met signal through the same survival and anti-apoptotic pathways, inhibition of the pair of receptors could improve overall efficacy. This was demonstrated clinically, where the combination of onartuzumab and erlotinib showed promising Phase II trials in lung cancer patients. Centyrins are small proteins (~10 kDa) of an emerging class of proteins termed alternative scaffolds. They are engineered to bind to target molecules with high specificity and affinity, but are structurally simpler molecules than antibodies in that that they are single chain, unglycosylated proteins that lack disulfide bonds. In addition, monomeric Centyrins can be linked together such that one molecule can bind to and inhibit multiple targets. Anti-EGFR and anti-c-Met Centyrins were selected for their ability to inhibit ligand-induced phosphorylation. Molecules with a wide range of affinities were identified and bispecific molecules were generated. Phosphorylation of EGFR, c-Met, and ERK were monitored in cells treated with individual monomeric Centyrins, a mixture of monomeric Centyrins, or linked bispecific Centyrins. One bispecific EGFR/c-Met Centyrin provided a 134-fold increase in potency in inhibition of phosphorylation of c-Met compared to the mixture of the two Centyrins. The increase in potency observed in cell signaling translated to enhanced anti-proliferative activity with a potency >100-fold compared to that of the mixture of monospecific Centyrins. The bispecific EGFR/c-Met Centyrins were produced as fusion proteins linked to an albumin binding domain in order to reduce kidney filtration and evaluated in SCID-beige mice implanted with tumor cells engineered to express human HGF. Interestingly, all of the Centyrins tested significantly reduced the size of the tumors compared to the control and the degree of tumor growth inhibition correlated with the affinity to both EGFR and c-Met. In a second tumor model, complete tumor regressions were observed in all mice treated with the bispecific EGFR/c-Met Centyrin. The Centyrin platform could offer benefits over currently available treatment options. Our data demonstrate that in addition to inhibiting two targets simultaneously, a single bispecific molecule allows for significant avidity at the cellular level. This could translate into a lower dosing regimen that allows for improved efficacy through avidity and decreased toxicity. We anticipate that avidity will allow for improved specificity for tumor compared to normal tissue. In addition, the small size of Centyrins may provide an advantage for tumor targeting and accumulation. Citation Format: Donna Klein, Steve Jacobs, Moores Sheri, Mark Anderson, Ricardo Attar, Alexander Barnakov, Kerry Brosnan, Barbara Bushey, Kristen Chevalier, Diana Chin, Carla Cornejo, Mike Diem, Linus Hyun, Elise Kuhar, Francis McCabe, Kristen Picha, Tracy Spinka-Doms, Edward Swift, Karyn O9Neil. Bispecific Centyrin simultaneously targeting EGFR and c-Met demonstrates improved activity compared to the mixture of single agents. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-312. doi:10.1158/1538-7445.AM2013-LB-312