Recent in vitro results suggest that the heterogeneous nuclear ribonucleoparticle (hnRNP) A1 protein modulates alternative splicing by favoring distal 5' splice site (5'SS) selection and exon skipping. We used a mouse erythroleukemia (MEL) cell line (CB3C7) deficient in the expression of hnRNP A1 to test whether variations in hnRNP A1 and AlB protein levels affected alternative splicing in vivo. In contrast to A1-expressing MEL cell lines, CB3C7 cells preferentially selected the proximal 13S and 12S 5'SS on the adenovirus E1A pre-mRNA. Transiently expressing the A1 or A1B cDNA in CB3C7 cells shifted 5'SS selection toward the more distal 9S donor site. A1 protein synthesis was required for this effect since the expression of a mutated A1 cDNA did not affect 5'SS selection. These results demonstrate that in vivo variations in hnRNP A1 protein levels can influence 5'SS selection.

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. On the basis of its histopathology and molecular-genomic changes, ovarian cancer has been divided into subtypes, each with distinct biology and outcome. The aim of this study was to develop a panel of patient-derived EOC xenografts that recapitulate the molecular and biologic heterogeneity of human ovarian cancer. Thirty-four EOC xenografts were successfully established, either subcutaneously or intraperitoneally, in nude mice. The xenografts were histologically similar to the corresponding patient tumor and comprised all the major ovarian cancer subtypes. After orthotopic transplantation in the bursa of the mouse ovary, they disseminate into the organs of the peritoneal cavity and produce ascites, typical of ovarian cancer. Gene expression analysis and mutation status indicated a high degree of similarity with the original patient and discriminate different subsets of xenografts. They were very responsive, responsive, and resistant to cisplatin, resembling the clinical situation in ovarian cancer. This panel of patient-derived EOC xenografts that recapitulate the recently type I and type II classification serves to study the biology of ovarian cancer, identify tumor-specific molecular markers, and develop novel treatment modalities. Cancer Res; 74(23); 6980–90. ©2014 AACR.

Activation of either Fli-1 or Spi-1 members of the ets family of transcription factors as a result of retroviral insertion and mutational inactivation of the p53 tumor suppressor gene play essential roles in the multistage erythroleukemias induced in mice by various strains of Friend virus. We have previously identified another common site for provirus integration, designated Fli-2 (Friend leukemia integration 2), in some erythroleukemia clones induced either by Friend murine leukemia virus (F-MuLV) or by the polycythemia-inducing strain of Friend virus complex (FV-P). Here we show that genomic sequences adjacent to Fli-2 correspond to the coding region of the erythroid-specific DNA binding protein NF-E2 p45. In one erythroleukemia cell line the expression of NF-E2 p45 is undetectable due to proviral integration in one allele and loss of the other allele. The complete loss of NF-E2 p45 in this cell line is associated with a drastic reduction in expression of the alpha- and beta-globin genes that were partially restored by reintroduction of the NF-E2 p45 gene. Taken together, these results provide direct evidence that NF-E2 gene is essential for globin transcription and suggest that perturbation in expression of this transcription factor may contribute to erythroleukemia progression.

The selective delivery of bioactive agents to tumors reduces toxicity and enhances the efficacy of anticancer therapies. In this study, we show that the antibody F8, which recognizes perivascular and stromal EDA-fibronectin (EDA-Fn), when conjugated to interleukin-2 (F8-IL2) can effectively inhibit the growth of EDA-Fn–expressing melanomas in combination with paclitaxel. We obtained curative effects with paclitaxel administered before the immunocytokine. Coadministration of paclitaxel increased the uptake of F8 in xenografted melanomas, enhancing tumor perfusion and permeability. Paclitaxel also boosted the recruitment of F8-IL2–induced natural killer (NK) cells to the tumor, suggesting a host response as part of the observed therapeutic benefit. In support of this likelihood, NK cell depletion impaired the antitumor effect of paclitaxel plus F8-IL2. Importantly, this combination reduced both the tumor burden and the number of pulmonary metastatic nodules. The combination did not cause cumulative toxicity. Together, our findings offer a preclinical proof that by acting on the tumor stroma paclitaxel potentiates the antitumor activity elicited by a targeted delivery of IL2, thereby supporting the use of immunochemotherapy in the treatment of metastatic melanoma. Cancer Res; 72(7); 1814–24. ©2012 AACR.

The clinical management of pancreatic ductal adenocarcinoma (PDAC) is hampered by the lack of reliable biomarkers. This study investigated the value of soluble stroma‐related molecules as PDAC biomarkers. In the first exploratory phase, 12 out of 38 molecules were associated with PDAC in a cohort of 25 PDAC patients and 16 healthy subjects. A second confirmatory phase on an independent cohort of 131 PDAC patients, 30 chronic pancreatitis patients, and 131 healthy subjects confirmed the PDAC association for MMP7, CCN2, IGFBP2, TSP2, sICAM1, TIMP1, and PLG. Multivariable logistic regression model identified biomarker panels discriminating respectively PDAC versus healthy subjects (MMP7 + CA19.9, AUC = 0.99, 99% CI = 0.98–1.00) (CCN2 + CA19.9, AUC = 0.96, 99% CI = 0.92–0.99) and PDAC versus chronic pancreatitis (CCN2 + PLG+FN+Col4 + CA19.9, AUC = 0.94, 99% CI = 0.88–0.99). Five molecules were associated with PanIN development in two GEM models of PDAC (PdxCre/LSL‐Kras^G12D and PdxCre/LSL‐Kras^G12D/+/LSL‐Trp53^R172H/+), suggesting their potential for detecting early disease. These markers were also elevated in patient‐derived orthotopic PDAC xenografts and associated with response to chemotherapy. The identified stroma‐related soluble biomarkers represent potential tools for PDAC diagnosis and for monitoring treatment response of PDAC patients. Synopsis Seven stroma‐related circulating biomarkers that discriminate between healthy subjects and pancreatic ductal adenocarcinoma (PDAC) in two different cohorts of patients have been identified and suggested as a potential diagnosis tool to monitor treatment efficacy in patients. Panels of biomarkers that improve the performance of CA19.9 in distinguishing i) PDAC from healthy subjects and ii) PDAC from chronic pancreatitis have been developed. Multivariable models confirmed their predictive accuracy at early stages of disease. The association of these biomarkers with the development of pre‐invasive disease in GEM models confirmed their potential to detect early stage lesions. The correlation of biomarker levels with tumor burden and drug response in patient‐derived PDAC xenograft models indicate their value to monitor treatment response and efficacy.