Novel Mouse Models of Bladder Cancer Identify a Prognostic Signature Associated with Risk of Disease Progression.

To study the progression of bladder cancer from non-muscle-invasive to muscle-invasive disease, we have developed a novel toolkit that uses complementary approaches to achieve gene recombination in specific cell populations in the bladder urothelium in vivo, thereby allowing us to generate a new series of genetically engineered mouse models (GEMM) of bladder cancer. One method is based on the delivery of adenoviruses that express Cre recombinase in selected cell types in the urothelium, and a second uses transgenic drivers in which activation of inducible Cre alleles can be limited to the bladder urothelium by intravesicular delivery of tamoxifen. Using both approaches, targeted deletion of the Pten and p53 tumor suppressor genes specifically in basal urothelial cells gave rise to muscle-invasive bladder tumors. Furthermore, preinvasive lesions arising in basal cells displayed upregulation of molecular pathways related to bladder tumorigenesis, including proinflammatory pathways. Cross-species analyses comparing a mouse gene signature of early bladder cancer with a human signature of bladder cancer progression identified a conserved 28-gene signature of early bladder cancer that is associated with poor prognosis for human bladder cancer and that outperforms comparable gene signatures. These findings demonstrate the relevance of these GEMMs for studying the biology of human bladder cancer and introduce a prognostic gene signature that may help to stratify patients at risk for progression to potentially lethal muscle-invasive disease. SIGNIFICANCE: Analyses of bladder cancer progression in a new series of genetically engineered mouse models has identified a gene signature of poor prognosis in human bladder cancer.

Tumor Evolution and Drug Response in Patient-Derived Organoid Models of Bladder Cancer.

Bladder cancer is the fifth most prevalent cancer in the U.S., yet is understudied, and few laboratory models exist that reflect the biology of the human disease. Here, we describe a biobank of patient-derived organoid lines that recapitulates the histopathological and molecular diversity of human bladder cancer. Organoid lines can be established efficiently from patient biopsies acquired before and after disease recurrence and are interconvertible with orthotopic xenografts. Notably, organoid lines often retain parental tumor heterogeneity and exhibit a spectrum of genomic changes that are consistent with tumor evolution in culture. Analyses of drug response using bladder tumor organoids show partial correlations with mutational profiles, as well as changes associated with treatment resistance, and specific responses can be validated using xenografts in vivo. Our studies indicate that patient-derived bladder tumor organoids represent a faithful model system for studying tumor evolution and treatment response in the context of precision cancer medicine.

ARF Confers a Context-Dependent Response to Chemotherapy in Muscle-Invasive Bladder Cancer.

Muscle-invasive bladder cancer (MIBC) generally responds poorly to treatment and tends to exhibit significant mortality. Here we show that expression of the tumor suppressor p14ARF (ARF) is upregulated in aggressive subtypes of MIBC. Accumulation of ARF in the nucleolus is associated with poor outcome and attenuated response to chemotherapy. In both genetically engineered mouse models and murine xenograft models of human MIBC, we demonstrate that tumors expressing ARF failed to respond to treatment with the platinum-based chemotherapy agent cisplatin. Resistance was mediated in part by the integrin-binding protein ITGB3BP (CENPR) and reflected ARF-dependent impairment of protein translation, which was exaggerated by drug treatment. Overall, our results highlight a context-dependent role for ARF in modulating the drug response of bladder cancer. Cancer Res; 77(4); 1035-46. ©2017 AACR.

Elevated PIM2 gene expression is associated with poor survival of patients with acute myeloid leukemia.

The PIM2 gene encodes the serine/threonine kinase involved in cell survival and apoptosis. The aim of the study was to evaluate the expression of the PIM2 gene in acute myeloid leukemia (AML) and to examine its role in apoptosis of the blastic cells. We analyzed the PIM2 expression in 148 patients: 91 with AML, 57 with acute lymphoblastic leukemia and 24 healthy controls by Real-Time PCR and Western blot. Inhibition of the PIM2 gene in human leukemic HL60 cell line was performed with RNAi and apoptosis rate was analyzed. Our results indicate that overexpression of PIM2 in AML is associated with low complete remission rate, high-risk cytogenetics, shorter leukemia-free survival, and event-free survival. Cytometric analysis of HL60/PAC-GFP and HL60/PAC-GFP-shPIM2 cells revealed an increase in the number of apoptotic cells after inhibition of PIM2 gene. In summary, the elevated expression of PIM2 in blastic cells is associated with poor prognosis of AML patients and their resistance to induction therapy.

Modelling bladder cancer in mice: opportunities and challenges.

The prognosis and treatment of bladder cancer have improved little in the past 20 years. Bladder cancer remains a debilitating and often fatal disease, and is among the most costly cancers to treat. The generation of informative mouse models has the potential to improve our understanding of bladder cancer progression, as well as to affect its diagnosis and treatment. However, relatively few mouse models of bladder cancer have been described, and in particular, few that develop invasive cancer phenotypes. This Review focuses on opportunities for improving the landscape of mouse models of bladder cancer.

Galactosylceramide affects tumorigenic and metastatic properties of breast cancer cells as an anti-apoptotic molecule.

It was recently proposed that UDP-galactose:ceramide galactosyltransferase (UGT8), enzyme responsible for synthesis of galactosylceramide (GalCer), is a significant index of tumor aggressiveness and a potential marker for the prognostic evaluation of lung metastases in breast cancer. To further reveal the role of UGT8 and GalCer in breast cancer progression, tumorigenicity and metastatic potential of control MDA-MB-231 cells (MDA/LUC) and MDA-MB-231 cells (MDA/LUC-shUGT8) with highly decreased expression of UGT8 and GalCer after stable expression of shRNA directed against UGT8 mRNA was studied in vivo in athymic nu/nu mice. Control MDA/LUC cells formed tumors and metastatic colonies much more efficiently in comparison to MDA/LUC-shUGT8 cells with suppressed synthesis of GalCer after their, respectively, orthotopic and intracardiac transplantation. These findings indicate that UGT8 and GalCer have a profound effect on tumorigenic and metastatic properties of breast cancer cells. In accordance with this finding, immunohistochemical staining of tumor specimens revealed that high expression of UGT8 accompanied by accumulation of GalCer in MDA-MB-231 cells is associated with a much higher proliferative index and a lower number of apoptotic cells in comparison to the MDA/LUC-shUGT8 cells. In addition, it was found that expression of UGT8 in MDA-MB-231 cells increased their resistance to apoptosis induced by doxorubicin in vitro. Therefore, these data suggest that accumulation of GalCer in tumor cells inhibits apoptosis, which would facilitates metastatic cells to survive in the hostile microenvironment of tumor in target organ.