A mouse model of human ZNF198-fibroblast growth factor receptor-1 (FGFR1) stem cell leukemia lymphoma has been developed to investigate mechanisms of oncogenesis and progression. Using array-based comparative genomic hybridization, we followed disease progression after serial transplantation of ZNF198-FGFR1-transformed stem cells that give rise to a distinct myeloproliferative disorder and T-lymphoblastic leukemia. A consistent, frequently homozygous, chr14:53880459-55011545 deletion, containing the T-cell receptor ␣ and ␦ genes, was identified in the bone marrow, spleen, and lymph nodes in all cases. The absence of cell-surface T-cell receptor ␣ in tumor cells precludes CD3 recruitment, resulting in loss of a functional T-cell receptor complex, supporting the idea that prevention of maturation of CD4 ؉ / CD8 ؉ double-positive immature T cells is important in ZNF198-FGFR1 disease development. Up-regulation of the B-cell line 2, interleukin 7 receptor ␣ and interleuking 2 receptor ␣ prosurvival genes in these undifferentiated tumor precursor cells suggests one mechanism that allows them to escape apoptosis in the thymus. Thus, we have defined an important event in the process of ZNF198- IntroductionHuman stem cell leukemia-lymphoma syndrome (SCLL), also known as 8p11 myeloproliferative syndrome, is a rare atypical myeloproliferative disorder. SCLL constitutes a clinical phenotype with features of both lymphoma and eosinophilic myeloproliferative disorders and is characterized by a reciprocal chromosome translocation, resulting in a chimeric protein that activates the kinase domain of the fibroblast growth factor receptor-1 (FGFR1). 1 To date, at least 8 gene partners have been shown to fuse to FGFR1, including ZNF198 on 13q12, 2,3 CEP110 on 9q33, 4 and FOP on 6q27 5 (see Tefferi and Gilliland 1 for review). The most commonly observed translocation is the t(8;13) (p11;q12), in which the zinc finger domain of ZNF198 is fused to the intracellular kinase domain of FGFR1. 2,3,6 Hepatosplenomegaly is characteristic of these myeloproliferative disorder patients, and almost all show T-lymphoblastic lymphoma, except for one case with B-cell acute lymphoblastic lymphoma. 7 The clinical course of SCLL is aggressive, with rapid transformation to acute myeloid leukemia and lymphoblastic lymphoma of common T-cell origin. [7][8][9][10][11] Treatment with conventional chemotherapy is often not effective, 12,13 and allogeneic bone marrow (BM) transplantation seems to be the only potentially curative therapeutic option. 7 In SCLL, both myeloid and lymphoid lineage cells exhibited the 8p11 translocation, suggesting a stem cell origin. The FGFR1 fusion protein in SCLL results in the constitutive and ligandindependent activitation of the FGFR1 signal transduction pathway, and is believed to be essential for disease pathogenesis, as evidenced in the clinical cases and murine models. 14,15 How the ZNF198-FGFR1 fusion kinase results in disease progression, however, remains unclear, as does its relationship with the development of concu...

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Background:The WASF3 protein is involved in cell movement and invasion, and to investigate its role in prostate cancer progression we studied the phenotypic effects of knockdown in primary tumors and cell lines.Methods:ShRNA was used to knockdown WASF3 function in prostate cell lines. Cell motility (scratch wound assay), anchorage independent growth and in vivo tumorigenicity and metastasis were then compared between knockdown and wild-type cells.Results:Increased levels of expression were seen in high-grade human prostate cancer and in the PC3 and DU145 cell lines. Inactivation of WASF3 using shRNAs reduced cell motility and invasion in these cells and reduced anchorage independent growth in vitro. The loss of motility was accompanied by an associated increase in stress fiber formation and focal adhesions. When injected subcutaneously into severe combined immunodeficiency (SCID) mice, tumor formation was significantly reduced for PC3 and DU145 cells with WASF3 knockdown and in vivo metastasis assays using tail vain injection showed a significant reduction for PC3 and DU145 cells. The loss of the invasion phenotype was accompanied by down-regulation of matrix metalloproteinase 9.Conclusions:Overall, these observations demonstrate a critical role for WASF3 in the progression of prostate cancer and identify a potential target to control tumorigenicity and metastasis.

BackgroundTransgelin is an actin-binding protein that promotes motility in normal cells. Although the role of transgelin in cancer is controversial, a number of studies have shown that elevated levels correlate with aggressive tumor behavior, advanced stage, and poor prognosis. Here we sought to determine the role of transgelin more directly by determining whether experimental manipulation of transgelin levels in colorectal cancer (CRC) cells led to changes in metastatic potential in vivo.MethodsIsogenic CRC cell lines that differ in transgelin expression were characterized using in vitro assays of growth and invasiveness and a mouse tail vein assay of experimental metastasis. Downstream effects of transgelin overexpression were investigated by gene expression profiling and quantitative PCR.ResultsStable overexpression of transgelin in RKO cells, which have low endogenous levels, led to increased invasiveness, growth at low density, and growth in soft agar. Overexpression also led to an increase in the number and size of lung metastases in the mouse tail vein injection model. Similarly, attenuation of transgelin expression in HCT116 cells, which have high endogenous levels, decreased metastases in the same model. Investigation of mRNA expression patterns showed that transgelin overexpression altered the levels of approximately 250 other transcripts, with over-representation of genes that affect function of actin or other cytoskeletal proteins. Changes included increases in HOOK1, SDCCAG8, ENAH/Mena, and TNS1 and decreases in EMB, BCL11B, and PTPRD.ConclusionsIncreases or decreases in transgelin levels have reciprocal effects on tumor cell behavior, with higher expression promoting metastasis. Chronic overexpression influences steady-state levels of mRNAs for metastasis-related genes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2105-8) contains supplementary material, which is available to authorized users.

Key Points CNTRL-FGFR1 induces AML and T-cell lymphoma in murine and human progenitor cells. Simultaneously targeting FGFR1, FLT3, KIT, and MYC synergistically induces cell growth inhibition in CNTRL-FGFR1–transformed cells.

Purpose: Histone deacetylase (HDAC) inhibitors have been shown to reverse epigenetic repression of certain genes, including retinoic acid receptor B2 (RARb2). In this study, we examined whether RARb2 expression is repressed in human renal cell carcinoma (RCC) and whether the HDAC inhibitor MS-275 may revert its epigenetic repression. Experimental Design: Six human tumor RCC cell lines were analyzed for RARb2 gene expression and for methylation and acetylation status at the promoter level. Modulation of RARb2 expression and correlation with antitumor activity by combination of MS-275 with 13-cis-retinoic acid (CRA) was assessed in a RARb2-negative RCC cell line. Results: RARb2 expression was either strongly present, weakly expressed, or absent in the RCC cell lines analyzed. Methylation-specific PCR indicated that the RARb2 promoter was partially methylated in three of the cell lines. CRA treatment did not inhibit clonogenic growth in the RARb2-negative cell line RCC1.18, whereas MS-275 induced a dose-dependent inhibitory effect. A greater inhibitory effect was observed with combination treatment (MS-275 + CRA).Treatment with MS-275 was associated with histone acetylation at the promoter level and synergistic gene reexpression of RARb2 in combination with CRA. RARb2 reexpression was associated with synergistic induction of the retinoid-responsive gene HOXA5. In vivo, single-agent CRA treatment showed no significant effect, whereas MS-275 and the combination induced a regression of RCC1.18 tumor xenografts. Discontinuation of treatment produced tumor recurrence in MS-275-treated mice, whereas animals treated with the combination remained tumor free. Conclusion: The HDAC inhibitor MS-275 seems to revert retinoid resistance due to epigenetic silencing of RARb2 in a human RCC model and has greater antitumor activity in combination with CRA compared with single agents. Thus, the combination of HDAC inhibitors and retinoids may represent a novel therapeutic approach in patients with RCC.

Stem cell leukemia/lymphoma syndrome (SCLL) is driven by constitutive activation of chimeric FGFR1 kinases generated by chromosome translocations. We have shown that FGFR inhibitors significantly suppress leukemia and lymphoma development in vivo, and cell viability in vitro. Since resistance to targeted therapies is a major reason for relapse, we developed FGFR1-overexpressing mouse and human cell lines that are resistant to the specific FGFR inhibitors AZD4547 and BGJ398, as well as non-specific inhibitors, such as ponatinib, TKI258 and E3810. Two mutually exclusive mechanisms for resistance were demonstrated; an activating V561M mutation in the FGFR1 kinase domain and mutational inactivation of PTEN resulting in increased PI3K/AKT activity. Ectopic expression of PTEN in the PTEN-mutant cells resensitizes them to FGFR inhibitors. Treatment of resistant cells with BGJ398, in combination with the BEZ235 PI3K inhibitor, shows an additive effect on growth in vitro and prolongs survival in xenograft models in vivo. These studies provide the first direct evidence for both the involvement of the FGFR1 V561M mutation and PTEN inactivation in the development of resistance in leukemias overexpressing chimeric FGFR1. These studies also provide a potential strategy to treat leukemias and lymphomas driven by FGFR1 activation that become resistant to FGFR1 inhibitors.

Abstract. Lung cancer is still the leading cause of cancerrelated deaths worldwide. Identifying new oncogenic drivers and developing efficient inhibitors through molecular targeting approaches are crucial for improving therapies. The aim of this study was to investigate whether targeting fibroblast growth factor receptor 1 (FGFR1) with ponatinib inhibits the cell growth in both established and primary lung cancer cells overexpressing FGFR1. Eighty-eight non-small cell lung cancer (NSCLC) and paired normal tissue specimens were analyzed by real-time RT-PCR for FGFR1 gene expression. We identified four cell lines and two newly established primary lung cancer cultures that showed high FGFR1 expression levels, and evaluated the effect of the novel FGFR1 inhibitor ponatinib on cell growth. Approximately 50% (30 out of 59) NSCLC specimens expressed FGFR1 >2-fold compared with their adjacent normal counterparts using quantitative RT-PCR. Ponatinib treatment of established NSCLC cell lines expressing higher levels of FGFR1 resulted in marked cell growth inhibition and suppression of clonogenicity. This growth inhibition was associated with inactivation of FGFR1 and its downstream targets. FGFR1 knockdown by shRNA achieved similar results when compared to treatment with ponatinib. Furthermore, ponatinib was able to significantly inhibit the growth of primary lung cancer cultures in vitro. Our data indicate that pharmacological inhibition of FGFR1 kinase activity with ponatinib may be effective for the treatment of lung cancer patients whose tumors overexpress FGFR1.