Single-cell analysis defines highly specific leukemia-induced neutrophils and links MMP8 expression to recruitment of tumor associated neutrophils during FGFR1 driven leukemogenesis.

Background: Leukemias driven by activated, chimeric FGFR1 kinases typically progress to AML which have poor prognosis. Mouse models of this syndrome allow detailed analysis of cellular and molecular changes occurring during leukemogenesis. We have used these models to determine the effects of leukemia development on the immune cell composition in the leukemia microenvironment during leukemia development and progression.

Identification of small molecules that suppress cell invasion and metastasis promoted by WASF3 activation.

The WASF3 gene promotes cancer cell invasion and metastasis, and genetic inactivation leads to suppression of metastasis. To identify small molecules that might interfere with WASF3 function, we performed an in silico docking study to the regulatory pocket of WASF3 using the National Cancer Institute (NCI) diversity set VI small molecule library. Compounds that showed the maximum likelihood of interaction with WASF3 were screened for their effect on cell movement in breast and prostate cancer cells, a well-established predictor of invasion and metastasis.

A truncated derivative of FGFR1 kinase cooperates with FLT3 and KIT to transform hematopoietic stem cells in syndromic and de novo AML.

Background: Myeloid and lymphoid malignancies associated with chimeric FGFR1 kinases are the hallmark of stem cell leukemia and lymphoma syndrome (SCLL). In all cases, FGFR1 kinase is constitutively phosphoactivated as a result of chromosome translocations, which lead to acquisition of dimerization motifs in the chimeric proteins. Recently, we demonstrated that these chimeric kinases could be cleaved by granzyme B to generate a truncated derivative, tnFGFR1, which localized exclusively into the nucleus and was not phosphorylated.

RHOA-regulated IGFBP2 promotes invasion and drives progression of BCR-ABL1 chronic myeloid leukemia.

The Philadelphia 9;22 chromosome translocation has two common isoforms that are preferentially associated with distinct subtypes of leukemia. The p210 variant is the hallmark of chronic myeloid leukemia (CML) whereas p190 is frequently associated with B-cell acute lymphoblastic leukemia. The only sequence difference between the two isoforms is the guanidine exchange factor domain.

Targeting the WASF3 complex to suppress metastasis.

Wiskott-Aldrich syndrome protein family members (WASF) regulate the dynamics of the actin cytoskeleton, which plays an instrumental role in cancer metastasis and invasion. WASF1/2/3 forms a hetero-pentameric complex with CYFIP1/2, NCKAP1/1 L, Abi1/2/3 and BRK1 called the WASF Regulatory Complex (WRC), which cooperatively regulates actin nucleation by WASF1/2/3. Activation of the WRC enables actin networking and provides the mechanical force required for the formation of lamellipodia and invadopodia.

IRAK1-regulated IFN-γ signaling induces MDSC to facilitate immune evasion in FGFR1-driven hematological malignancies.

Background: Stem Cell leukemia/lymphoma syndrome (SCLL) presents as a myeloproliferative disease which can progress to acute myeloid leukemia and is associated with the coincident development of B-cell and T-cell lymphomas. SCLL is driven by the constitutive activation of fibroblast growth factor receptor-1 (FGFR1) as a result of chromosome translocations with poor outcome. Mouse models have been developed which faithfully recapitulate the human disease and have been used to characterize the molecular genetic events that are associated with development and progression of the disease.

Mechanisms of resistance to FGFR1 inhibitors in FGFR1-driven leukemias and lymphomas: implications for optimized treatment.

Myeloid and lymphoid neoplasms with eosinophilia and FGFR1 rearrangements (MLN-eo FGFR1) disease is derived from a pluripotent hematopoietic stem cell and has a complex presentation with a myeloproliferative disorder with or without eosinophilia and frequently presents with mixed lineage T- or B-lymphomas. The myeloproliferative disease frequently progresses to AML and lymphoid neoplasms can develop into acute lymphomas. No matter the cell type involved, or clinical presentation, chromosome translocations involving the kinase and various partner genes, which leads to constitutive activation of downstream oncogenic signaling cascades.

Variant profiles of genes mapping to chromosome 16q loss in Wilms tumors reveals link to cilia-related genes and pathways.

Background: Wilms tumor is the most common pediatric renal tumor and the fourth most common malignancy in children. Chromosome 16q deletion(del) or loss of heterozygosity (LOH) has been correlated with recurrence and overall poor prognosis, such that patients with 16qLOH and 1p allelic loss are treated with more aggressive chemotherapeutic regimens.

Methods: In the present study, we have compared the variant profiles of Wilms tumors with and without 16q del/LOH using both data available from the TARGET database (42 samples) and tumors procured from our legacy collection (8 samples).

Downregulation of PUMA underlies resistance to FGFR1 inhibitors in the stem cell leukemia/lymphoma syndrome.

Resistance to molecular therapies frequently occur due to genetic changes affecting the targeted pathway. In myeloid and lymphoid leukemias/lymphomas resulting from constitutive activation of FGFR1 kinases, resistance has been shown to be due either to mutations in FGFR1 or deletions of PTEN. RNA-Seq analysis of the resistant clones demonstrates expression changes in cell death pathways centering on the p53 upregulated modulator of apoptosis (Puma) protein.

DNA methyltransferase 1-mediated CpG methylation of the miR-150-5p promoter contributes to fibroblast growth factor receptor 1-driven leukemogenesis.

MicroRNA-150-5p (miR-150-5p) plays a complex role in normal early hematopoietic development and is also implicated in the development of various different leukemias. We have reported previously that, in myeloid and lymphoid malignancies associated with dysregulated fibroblast growth factor receptor 1 (FGFR1) activities, miR-150-5p is down-regulated compared with healthy cells. Here, using murine cells, we found that this down-regulation is accompanied by CpG methylation of the miR-150-5p promoter region.

Wasf3 Deficiency Reveals Involvement in Metastasis in a Mouse Model of Breast Cancer.

The WASF3 gene has been implicated in cancer cell movement, invasion, and metastasis by regulating genetic pathways important in these processes. Invasion and metastasis assays, however, are largely centered on xenograft models in immune-compromised mice. To facilitate analysis of the role of WASF3 in the spontaneous development of cancer cell metastasis, we generated a Wasf3 null strain by deleting exons 4 and 5, which encode essential motifs for Wasf3 function.

Critical individual roles of the BCR and FGFR1 kinase domains in BCR-FGFR1-driven stem cell leukemia/lymphoma syndrome.

Constitutive activation of FGFR1, as a result of diverse chromosome translocations, is the hallmark of stem cell leukemia/lymphoma syndrome. The BCR-FGFR1 variant is unique in that the BCR component contributes a serine-threonine kinase (STK) to the N-terminal end of the chimeric FGFR1 kinase. We have deleted the STK domain and mutated the critical Y177 residue and demonstrate that the transforming activity of these mutated genes is reduced compared to the BCR-FGFR1 parental kinase.

Inactivation of Lgi1 in murine neuronal precursor cells leads to dysregulation of axon guidance pathways.

LGI1 mutations predispose to a rare epilepsy syndrome and when inactivated in mice leads to early onset seizures and premature death. Histopathology of the mature brain soon after birth shows cortical dysplasia in Lgi1 null mice with hypercellularity in the outer cortical layers. Here we show extensive gene expression changes in neuronal precursor cells from Lgi1 null mice compared with wild type mice.

Correction: The pleiotropic effects of TNFα in breast cancer subtypes is regulated by TNFAIP3/A20.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Primary tumor-induced immunity eradicates disseminated tumor cells in syngeneic mouse model.

Although clinically apparent metastasis is associated with late stages of cancer development, micro-metastatic dissemination may be an early event. However, the fate of these early disseminated tumor cells (DTC) remains elusive. We show that despite their capacity to disseminate into secondary organs, 4T1 tumor models develop overt metastasis while EMT6-tumor bearing mice clear DTCs shed from primary tumors as well as those introduced by intravenous (IV) injection.

The co-chaperone UNC45A is essential for the expression of mitotic kinase NEK7 and tumorigenesis.

Cumulative evidence suggests that the heat shock protein 90 (Hsp90) co-chaperone UNC-45 myosin chaperone A (UNC45A) contributes to tumorigenesis and that its expression in cancer cells correlates with proliferation and metastasis of solid tumors. However, the molecular mechanism by which UNC45A regulates cancer cell proliferation remains largely unknown. Here, using siRNA-mediated gene silencing and various human cells, we report that UNC45A is essential for breast cancer cell growth, but is dispensable for normal cell proliferation.

Selective inactivation of LGI1 in neuronal precursor cells leads to cortical dysplasia in mice.

Constitutional mutations in Leucine-rich glioma inactivated 1 (LGI1) predispose to an autosomal dominant epilepsy syndrome in humans and germline inactivation of LGI1 in mice leads to early onset seizures. LGI1 is highly expressed in the regions involved in neuronal stem cell generation and migration and detailed analysis of the brains in these mice reveals a subtle cortical dysplasia characterized by hypercellularity in the outer cortical layers. To investigate the cellular origin for this cortical dysplasia, we created mice that allow cell-specific, conditional inactivation of LGI1.

Distinct signaling programs associated with progression of FGFR1 driven leukemia in a mouse model of stem cell leukemia lymphoma syndrome.

Constitutive activation of FGFR1 as a result of chromosome translocations is responsible for the development of a hematopoietic stem cell disorder that progresses to AML. We have developed a syngeneic mouse model of BCR-FGFR1 driven AML and used RNASeq to define gene expression signatures associated with disease progression. The development of the leukemic stem cells (LSC) is associated with a profound downregulation of specific transcription factors that normally maintain stem cell quiescence as well as cell adhesion and motility gene sets related to confinement to the stem cell niche.

Loss of the BCR-FGFR1 GEF Domain Suppresses RHOA Activation and Enhances B-Lymphomagenesis in Mice.

Transformation of hematopoietic stem cells by the BCR-FGFR1 fusion kinase found in a variant of stem cell leukemia/lymphoma (SCLL) syndrome leads to development of B-lymphomas in syngeneic mice and humans. In this study, we show that the relatively rapid onset of this leukemia is potentially related to oncogenic domains within the BCR component. BCR recruited a guanidine nucleotide exchange factor (GEF) domain to the fusion kinase to facilitate activation of small GTPases such as the Ras homology gene family, member A (RHOA).

The pleiotropic effects of TNFα in breast cancer subtypes is regulated by TNFAIP3/A20.

TNFα is a pleiotropic cytokine which fuels tumor cell growth, invasion, and metastasis in some malignancies, while in others it induces cytotoxic cell death. However, the molecular mechanism by which TNFα exerts its diverse effects on breast cancer subtypes remains elusive. Using in vitro assays and mouse xenografts, we show here that TNFα contributes to the aggressive properties of triple negative breast cancer (TNBC) cell lines via upregulation of TNFAIP3(A20).

miR-339 Promotes Development of Stem Cell Leukemia/Lymphoma Syndrome via Downregulation of the and Proapoptotic Genes.

The development of myeloid and lymphoid neoplasms related to overexpression of FGFR1 kinases as a result of chromosome translocations depends on the promotion of a stem cell phenotype, suppression of terminal differentiation, and resistance to apoptosis. These phenotypes are related to the stem cell leukemia/lymphoma syndrome (SCLL), which arises through the effects of the activated FGFR1 kinase on gene transcription, which includes miRNA dysregulation. In a screen for miRNAs that are directly regulated by FGFR1, and which stimulate cell proliferation and survival, we identified miR-339-5p, which is highly upregulated in cells carrying various different chimeric kinases.

FGFR1 fusion kinase regulation of MYC expression drives development of stem cell leukemia/lymphoma syndrome.

Oncogenic transformation of hematopoietic stem cells by chimeric fusion kinases causing constitutive activation of FGFR1 leads to a stem cell leukemia/lymphoma (SCLL) syndrome, accompanied by widespread dysregulation of gene activity. We now show that FGFR1 activation is associated with upregulation of MYC and pharmacological suppression of FGFR1 activation leads to downregulation of MYC and suppression of MYC target genes. Luciferase reporter assays demonstrate that FGFR1 can directly regulate MYC expression and this effect is enhanced in the presence of chimeric FGFR1 kinases.

Celecoxib Ameliorates Seizure Susceptibility in Autosomal Dominant Lateral Temporal Epilepsy.

Autosomal dominant lateral temporal epilepsy (ADLTE) is an inherited syndrome caused by mutations in the leucine-rich glioma inactivated 1 (LGI1) gene. It is known that glutamatergic transmission is altered in LGI1 mutant mice, and seizures can be reduced by restoring LGI1 function. Yet, the mechanism underlying ADLTE is unclear.

The miR-17/92 cluster is involved in the molecular etiology of the SCLL syndrome driven by the BCR-FGFR1 chimeric kinase.

MicroRNAs (miRNAs) have pathogenic roles in the development of a variety of leukemias. Here we identify miRNAs that have important roles in the development of B lymphomas resulting from the expression of the chimeric BCR-FGFR1 kinase. The miR-17/92 cluster was particularly implicated and forced expression resulted in increased cell proliferation, while inhibiting its function using miRNA sponges reduced cell growth and induced apoptosis.