PURPOSE Obesity promotes pancreatic and breast cancer progression via mechanisms that are poorly understood. Although obesity is associated with increased systemic levels of placental growth factor (PlGF), the role of PlGF in obesity-induced tumor progression is not known. PlGF and its receptor vascular endothelial growth factor receptor-1 (VEGFR-1) have been shown to modulate tumor angiogenesis and promote tumor-associated macrophage (TAM) recruitment and activity. Here, we hypothesized that increased activity of PlGF/VEGFR-1 signaling mediates obesity-induced tumor progression by augmenting tumor angiogenesis and TAM recruitment/activity. EXPERIMENTAL DESIGN We established diet-induced obese mouse models of wild type C57BL/6, VEGFR-1 tyrosine kinase (TK)-null or PlGF null mice, and evaluated the role of PlGF/VEGFR-1 signaling in pancreatic and breast cancer mouse models and in human samples. RESULTS We found that obesity increased TAM infiltration, tumor growth and metastasis in pancreatic cancers, without affecting vessel density. Ablation of VEGFR-1 signaling prevented obesity-induced tumor progression and shifted the tumor immune environment towards an anti-tumor phenotype. Similar findings were observed in a breast cancer model. Obesity was associated with increased systemic PlGF, but not VEGF-A or VEGF-B, in pancreatic and breast cancer patients and in various mouse models of these cancers. Ablation of PlGF phenocopied the effects of VEGFR-1-TK deletion on tumors in obese mice. PlGF/VEGFR-1-TK deletion prevented weight gain in mice fed a high-fat diet, but exacerbated hyperinsulinemia. Addition of metformin not only normalized insulin levels but also enhanced anti-tumor immunity. CONCLUSIONS Targeting PlGF/VEGFR-1 signaling reprograms the tumor immune microenvironment and inhibits obesity-induced acceleration of tumor progression.

Background Advanced cholangiocarcinoma carries a poor prognosis, and no standard treatment exists beyond the first-line gemcitabine/platinum-based chemotherapy. We performed a single arm phase II and biomarker study of cabozantinib, a multikinase inhibitor with potent activity against VEGFR2 and MET, in patients with advanced refractory cholangiocarcinoma. Methods Previously treated patients with unresectable or metastatic cholangiocarcinoma received cabozantinib 60 mg orally daily continuously. The primary endpoint was progression free survival (PFS). Tumor MET expression and plasma biomarkers were evaluated. Results The study enrolled 19 patients with cholangiocarcinoma (female 68%; median age 67yo; intra- vs extrahepatic, 84% vs 16%). The median PFS was 1.8 months (95%CI; 1.6, 5.4), and the median overall survival was 5.2 months (95%CI; 2.7, 10.5). Grade 3/4 adverse events occurred in 89% of patients, and included neutropenia (5%), hyperbilirubinemia (5%), epistaxis (5%), bowel perforation (5%), enterocutaneous fistula (5%), and hypertension (11%). One patient with 3+ MET expression in the tumor stayed on treatment for 278 days, but MET expression did not correlate with outcomes in the overall study population. Plasma VEGF, PlGF and SDF1α increased and soluble VEGFR2 and Ang2 decreased after treatment (all p<0.01). Plasma TIMP-1 inversely correlated with PFS, and soluble MET (sMET) and IL-6 inversely correlated with OS. Conclusions In unselected patients with cholangiocarcinoma, cabozantinib demonstrated limited activity and significant toxicity. In the first clinical trial to assess the role of MET inhibition in cholangiocarcinoma, one patient with a MET-high tumor had prolonged benefit from treatment. Baseline plasma sMET was associated with OS. Any further development of this drug in cholangiocarcinoma should include dose reduction and a biomarker-driven approach.

Only about half of non-membrane-bound proteins encoded by either bacterial or archaeal genomes are soluble when expressed in Escherichia coli (Yee et al., Proc Natl Acad Sci USA 2002;99:1825-1830; Christendat et al., Prog Biophys Mol Biol 200;73:339-345). This property limits genome-scale functional and structural proteomics studies, which depend on having a recombinant, soluble version of each protein. An emerging strategy to increase the probability of deriving a soluble derivative of a protein is to study different sequence homologues of the same protein, including representatives from thermophilic organisms, based on the assumption that the stability of these proteins will facilitate structural analysis. To estimate the relative merits of this strategy, we compared the recombinant expression, solubility, and suitability for structural analysis by NMR and/or X-ray crystallography for 68 pairs of homologous proteins from E. coli and Thermotoga maritima. A sample suitable for structural studies was obtained for 62 of the 68 pairs of homologs under standardized growth and purification procedures. Fourteen (eight E. coli and six T. maritima proteins) samples generated NMR spectra of a quality suitable for structure determination and 30 (14 E. coli and 16 T. maritima proteins) samples formed crystals. Only three (one E. coli and two T. maritima proteins) samples both crystallized and had excellent NMR properties. The conclusions from this work are: (1) The inclusion of even a single ortholog of a target protein increases the number of samples for structural studies almost twofold; (2) there was no clear advantage to the use of thermophilic proteins to generate samples for structural studies; and (3) for the small proteins analyzed here, the use of both NMR and crystallography approaches almost doubled the number of samples for structural studies.

Introduction We describe the use of telepathology in countries with restricted resources using two diagnosis assistance systems (Isabel and Memem7) in addition to the diagnoses made by experts in pathology via the iPath-Network. Methods A total of 156 cases, largely from Afghanistan, were analysed; 18 cases had to be excluded because of poor image quality. Results Of the remaining 138 cases (100%), a responsible physician provided a tentative diagnosis for 61.6% of them. With a diagnosis from a consultant pathologist, it was then possible to make a definite diagnosis in 84.8% of cases on the basis of images taken from hematoxylin and eosin staining sections alone. The use of the diagnosis assistance systems resulted in an ordered list of differential diagnoses in 82.6% (IsabelHealth) and in 74.6% (Memem7) of cases, respectively. Adding morphological terminology reduced the list of possible diagnoses to 52.2% (72 cases, Memem7), but improved their quality. Discussion In summary, diagnosis assistance systems are promising approaches to provide physicians in countries with restricted resources with lists of probable differential diagnoses, thus increasing the plausibility of the diagnosis of the consultant pathologist.