Anti-inflammatory and immunomodulatory effects of bortezomib in various in vivo models.

Bortezomib (Velcade®) is a proteasome inhibitor that has been approved for the treatment of multiple myeloma and mantle cell lymphoma. It has been shown to inhibit the expression of cell adhesion molecules, co-stimulatory molecules, and NFκB activation, to deplete alloreactive T lymphocytes, and to decrease Th1 cytokine production. The anti-inflammatory effects of bortezomib were further investigated in this current set of studies. Systemic treatment with bortezomib was efficacious in the thioglycolate-induced MCP-1 production model, and the dinitrofluorobenzene-induced delayed-type hypersensitivity model. Psoriasis is an autoimmune disease that affects about 2% of the world population. Many treatments have been reported with varying degrees of efficacy. A topical bortezomib formulation was developed to minimize systemic exposure. Its tolerability was investigated in a topical imiquimod (IMQ)-induced psoriasis model. Daily application of IMQ on mouse skin induced inflamed scaly skin lesions resembling plaque-type psoriasis. Fatality was observed in the 1-mg/ml dose group. At 0.1 and 0.01 mg/ml, bortezomib potentiated IMQ-induced erythema, scaling, skin thickening, and caused necrotic lesions. Lower doses had no effect on the clinical observations. Histologically, bortezomib dose-dependently increased parakeratosis, hyperkeratosis, acanthosis, and inflammatory cell infiltration. This study demonstrated that topical bortezomib is not suitable for the treatment of psoriasis

A Patient-Derived Xenograft Model of Parameningeal Embryonal Rhabdomyosarcoma for Preclinical Studies.

Embryonal rhabdomyosarcoma (eRMS) is one of the most common soft tissue sarcomas in children and adolescents. Parameningeal eRMS is a variant that is often more difficult to treat than eRMS occurring at other sites. A 14-year-old female with persistent headaches and rapid weight loss was diagnosed with parameningeal eRMS. She progressed and died despite chemotherapy with vincristine, actinomycin-D, and cyclophosphamide plus 50.4 Gy radiation therapy to the primary tumor site. Tumor specimens were acquired by rapid autopsy and tumor tissue was transplanted into immunodeficient mice to create a patient-derived xenograft (PDX) animal model. As autopsy specimens had an ALK R1181C mutation, PDX tumor bearing animals were treated with the pan-kinase inhibitor lestaurtinib but demonstrated no decrease in tumor growth, suggesting that single agent kinase inhibitor therapy may be insufficient in similar cases. This unique parameningeal eRMS PDX model is publicly available for preclinical study. Sarcoma 2015; 2015:826124

A Patient-Derived Xenograft Model of Parameningeal Embryonal Rhabdomyosarcoma for Preclinical Studies

Embryonal rhabdomyosarcoma (eRMS) is one of the most common soft tissue sarcomas in children and adolescents. Parameningeal eRMS is a variant that is often more difficult to treat than eRMS occurring at other sites. A 14-year-old female with persistent headaches and rapid weight loss was diagnosed with parameningeal eRMS. She progressed and died despite chemotherapy with vincristine, actinomycin-D, and cyclophosphamide plus 50.4 Gy radiation therapy to the primary tumor site. Tumor specimens were acquired by rapid autopsy and tumor tissue was transplanted into immunodeficient mice to create a patient-derived xenograft (PDX) animal model. As autopsy specimens had an ALK R1181C mutation, PDX tumor bearing animals were treated with the pan-kinase inhibitor lestaurtinib but demonstrated no decrease in tumor growth, suggesting that single agent kinase inhibitor therapy may be insufficient in similar cases. This unique parameningeal eRMS PDX model is publicly available for preclinical study

EphB4/EphrinB2 therapeutics in Rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma affecting children and is often diagnosed with concurrent metastases. Unfortunately, few effective therapies have been discovered that improve the long-term survival rate for children with metastatic disease. Here we determined effectiveness of targeting the receptor tyrosine kinase, EphB4, in both alveolar and embryonal RMS either directly through the inhibitory antibody, VasG3, or indirectly by blocking both forward and reverse signaling of EphB4 binding to EphrinB2, cognate ligand of EphB4. Clinically, EphB4 expression in eRMS was correlated with longer survival. Experimentally, inhibition of EphB4 with VasG3 in both aRMS and eRMS orthotopic xenograft and allograft models failed to alter tumor progression. Inhibition of EphB4 forward signaling using soluble EphB4 protein fused with murine serum albumin failed to affect eRMS model tumor progression, but did moderately slow progression in murine aRMS. We conclude that inhibition of EphB4 signaling with these agents is not a viable monotherapy for rhabdomyosarcoma

Features of human xenograft model systems.

<p>Features of human xenograft model systems.</p

VasG3 treatment of PCB82 eRMS xenografts.

<p><i>A</i>. Kaplan-Meier curve demonstrating percent event-free survival based on day post-treatment. Isotype control (black line) versus VasG3 (red line). p = 0.351, n = 6 female mice per cohort. <i>B</i>. Western blot demonstrating loss of EphB4 protein levels following VasG3 treatment. <i>C</i>. Differences in EphB4 protein levels following VasG3 treatment were quantified with densitometry. **p = 0.006.</p

EphrinB2 blockade by sEphB4-HSA in human eRMS xenograft models.

<p><i>A</i>, <i>B</i>. Kaplan-Meier curves for Rh18 (A) or PCB82 (B) xenograft models. n = 10–12 female mice per cohort per experiment. Black line, human serum albumin (HSA) control. Red line, soluble EphB4-HSA treatment. <i>C</i>, <i>D</i>. Western blots (C) showing Src phosphorylation from PCB82 human eRMS xenograft, lysates treated <i>in vivo</i> with either HSA or sEphB4-HSA were quantified for differences using densitometry (D). n = 10–11 female mcie per PCB82 cohort. p = 0.2539.</p

EphB4 and EphrinB2 expression in model systems of human eRMS.

<p><i>A</i>. Patient survival improves with high EphB4 expression determined using the. p = 0.0033, n = 72. <i>B</i>. Human eRMS expression of EphB4 and EphrinB2, respectively, of PCB82 tissue sections from a human eRMS tissue microarray. Control skeletal muscle from the same TMA is depicted in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0183161#pone.0183161.g001" target="_blank">Fig 1B</a>. <i>C</i>. Human eRMS expression of EphB4 and EphrinB2 in Rh18 xenograft sections. Mag bar = 50 μm. <i>D</i>. Representative western blot demonstrating EphB4 and EphrinB2 protein expression in human eRMS xenograft models, PCB82 and Rh18.</p

Immunohistochemistry of embryonal rhabdomyosarcoma tissue microarrays.

<p>Immunohistochemistry of embryonal rhabdomyosarcoma tissue microarrays.</p