Collagen cross-linking treatment increases adhesion in mock corneal grafts.

PURPOSE: We tested the hypothesis that collagen cross-linking (CXL) could be used to promote adhesion in mock corneal grafts. METHODS: Donated human corneal tissue underwent epithelial debridement and was cut into sections measuring 4mm×3mm. Paired sections were sutured together with 10-0 vicryl, forming mock corneal grafts. Looped 6-0 sutures were placed at each end to facilitate tension measurement. Mock grafts underwent CXL before being cultured for 2days in Eagle's MEM culture medium. Control mock grafts did not undergo CXL treatment before culture. Tissue was obtained from 4 donors and a maximum of 2 controls and 2 treated grafts was obtained from each donor. Following the culture period, the 10-0 sutures were cut. The mock grafts were mounted on force transducers and were put under increasing tension until eventually the sections were pulled apart. RESULTS: The mean applied stress required to generate graft failure was calculated for all mock grafts±standard error of the mean. In the control group 0.236±0.09mPa of applied stress was required to cause graft failure, in comparison to 0.691±0.12mPa in the treated group. A paired t-test showed this result to be significant, (p=0.0087). CONCLUSION: The results of our study are consistent with our hypothesis that CXL treatment could be used to promote early adhesion between separate sections of corneal tissue.

CXCR2 Inhibition Profoundly Suppresses Metastases and Augments Immunotherapy in Pancreatic Ductal Adenocarcinoma.

CXCR2 has been suggested to have both tumor-promoting and tumor-suppressive properties. Here we show that CXCR2 signaling is upregulated in human pancreatic cancer, predominantly in neutrophil/myeloid-derived suppressor cells, but rarely in tumor cells. Genetic ablation or inhibition of CXCR2 abrogated metastasis, but only inhibition slowed tumorigenesis. Depletion of neutrophils/myeloid-derived suppressor cells also suppressed metastasis suggesting a key role for CXCR2 in establishing and maintaining the metastatic niche. Importantly, loss or inhibition of CXCR2 improved T cell entry, and combined inhibition of CXCR2 and PD1 in mice with established disease significantly extended survival. We show that CXCR2 signaling in the myeloid compartment can promote pancreatic tumorigenesis and is required for pancreatic cancer metastasis, making it an excellent therapeutic target.

Framework for ethical decision-making based on mission, vision and values of the institution.

The authors led the development of a framework for ethical decision-making for an Academic Health Sciences Centre. They understood the existing mission, vision, and values statement (MVVs) of the centre as a foundational assertion that embodies an ethical commitment of the institution. Reflecting the Patient and Family Centred Model of Care the institution is living, the MVVs is a suitable base on which to construct an ethics framework. The resultant framework consists of a set of questions for each of the MVVs. Users of the framework are expected to identify two or more possible decisions to address the issue at hand and then, by applying the provided sequence of questions to each, examine these options and determine the overall ethically preferable decision. The construction of such a framework requires the creative involvement of the institution's staff. Thus the development of the framework can represent a training process in ethical decision-making as well as advance the ethical atmosphere of the institution. This novel approach has the advantage of placing the MVVs on active duty, at the centre of ethical decision-making, and lifts it from its otherwise relative obscurity in most institutions.

Tumor stromal architecture can define the intrinsic tumor response to VEGF-targeted therapy.

PURPOSE: The aim of the study was to investigate the vascular and stromal architecture of preclinical tumor models and patient tumor specimens from malignancies with known clinical outcomes to VEGFi treatment, to gain insight into potential determinants of intrinsic sensitivity and resistance. EXPERIMENTAL DESIGN: The tumor stroma architecture of preclinical and clinical tumor samples were analyzed by staining for CD31 and α-smooth muscle actin (α-SMA). Tumor models representative of each phenotype were then tested for sensitivity to the VEGFR2-blocking antibody DC101. RESULTS: Human tumor types with high response rates to VEGF inhibitors (e.g., renal cell carcinoma) have vessels distributed amongst the tumor cells (a "tumor vessel" phenotype, TV). In contrast, those malignancies where single-agent responses are lower, such as non-small cell lung cancer (NSCLC), display a complex morphology involving the encapsulation of tumor cells within stroma that also supports the majority of vessels (a "stromal vessel" phenotype). Only 1 of 31 tumor xenograft models displayed the stromal vessel phenotype. Tumor vessel models were sensitive to VEGFR2-blocking antibody DC101, whereas the stromal vessel models were exclusively refractory. The tumor vessel phenotype was also associated with a better Response Evaluation Criteria in Solid Tumors (RECIST) response to bevacizumab + chemotherapy in metastatic colorectal cancer (CRC). CONCLUSION: The tumor stromal architecture can differentiate between human tumor types that respond to a VEGF signaling inhibitor as single-agent therapy. In addition to reconciling the clinical experience with these agents versus their broad activity in preclinical models, these findings may help to select solid tumor types with intrinsic sensitivity to a VEGFi or other vascular-directed therapies.

An antibody targeted to VEGFR-2 Ig domains 4-7 inhibits VEGFR-2 activation and VEGFR-2-dependent angiogenesis without affecting ligand binding.

Inhibition of VEGFR-2 signaling reduces angiogenesis and retards tumor growth. Current biotherapeutics that inhibit VEGFR-2 signaling by either sequestering VEGF ligand or inhibiting VEGF binding to VEGFR-2 may be compromised by high VEGF concentrations. Here we describe a biotherapeutic that targets VEGFR-2 signaling by binding to Ig domains 4-7 of VEGFR-2 and therefore has the potential to work independently of ligand concentration. 33C3, a fully human VEGFR-2 antibody, was generated using XenoMouse technology. To elucidate the mechanism of action of 33C3, we have used a number of competition and binding assays. We show that 33C3 binds VEGFR-2 Ig domains 4-7, has no impact on VEGF-A binding to VEGFR-2, and does not compete with an antibody that interacts at the ligand binding site. 33C3 has a high affinity for VEGFR-2 (K(D) < 1 nmol/L) and inhibits VEGF-A induced phosphorylation of VEGFR-2 with an IC(50) of 99 ± 3 ng/mL. In vitro, in a 2D angiogenesis assay, 33C3 potently inhibits both tube length and number of branch points, and endothelial tubule formation in a 3D assay. In vivo, 33C3 is a very effective inhibitor of angiogenesis in both a human endothelial angiogenesis assay and in a human skin chimera model. These data show targeting VEGFR-2 outside of the ligand binding domain results in potent inhibition of VEGFR-2 signaling and inhibition of angiogenesis in vitro and in vivo.