Suyun Huang - US grants

[unreadable] DESCRIPTION (provided by applicant): Malignant gliomas are the most common brain tumors and are associated with extremely high rates of morbidity and mortality. The long-term goal of our research is to reveal the molecular mechanisms underlying glioma development and progression, of which very little is currently known. Recent studies using oligonucleotide microarray analysis have shown that alteration to the Forkhead box M1 (FoxM1) transcription factor is one of the most frequent molecular alterations in malignant gliomas. Our preliminary results indicate a direct correlation between FoxM1 expression level and the grade of gliomas. Enforced FoxM1 expression in immortalized normal human astrocytes (NHAs) was sufficient to transform the cells into glioma cells. Enforced FoxM1 expression in anaplastic astrocytoma cells promoted their progression into glioblastomas in nude mouse models, and suppressed FoxM1 expression inhibited the anchorage-independent growth of glioblastoma cells. Moreover, gliomas arisen from FoxM1-transfected cells were highly proliferative, invasive, and angiogenic. FoxM1-transfected glioma cells had increased expression of activated Akt, VEGF and MMP-2, whereas FoxM1-siRNA-transfected glioma cells had decreased expression of activated Akt. Here, we propose to determine the causal effects and mechanisms of aberrant FoxM1 expression on glioma development and progression. We hypothesize that aberrant expression of FoxM1 contributes to glioma development and progression by promoting uncontrolled cell proliferation, invasion, and angiogenesis. Our Specific Aims are 1) To determine the effect of altered FoxM1 expression on glioma biology. We will determine the critical contribution of FoxM1 to glioma cell proliferation, invasion, and angiogenesis in vitro and in vivo by using the FoxM1-siRNA inhibition system, FoxM1-overexpressing cell lines, and in vivo mouse models. 2) To determine the cooperation between FoxM1 overexpression and Rb loss in glioma development and progression. We will investigate whether FoxM1 transgene expression accelerates glioma formation and promotes glioma progression in a genetic mouse glioma model with an inactivated pRb pathway. 3) To determine whether FoxM1 overexpression contributes to glioma development and progression via activation of Akt pathway. 4) To identify the molecular mechanisms by which FoxM1 regulates glioma invasion and angiogenesis. The mechanisms of FoxM1 regulating invasion and angiogenesis will be investigated with a particular focusing on how it regulates the expression of the MMP-2, and VEGF genes. The findings from our proposed studies will contribute to a better understanding of the molecular mechanisms of glioma development and progression and will identify potential targets for novel therapeutic strategies against malignant glioma. [unreadable] [unreadable] [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Malignant glioma, the most common primary brain tumor subtype, is aggressive and neurologically destructive. The mean survival duration of patients with glioblastoma multiforme (GBM), the most common form of glioma, is approximately 1 year and there is no effective therapy to date. Little is known about the molecular mechanisms underlying GBM oncogenesis. The malignant phenotype of human GBM may be driven by GBM-derived stem-like cells (GSCs). One of the key issues for our understanding of cancer stem cells is to define the molecular circuitry that drives the development and self-renewal of the cancer stem cells. Based on our recent experimental results, we propose to evaluate the novel hypothesis that FoxM1, which is abnormally expressed in human GBM-derived stem-like cells (GSCs), causes a high self-renewal rate in the "stem-like" cells present in the tumor, possibly through a PDGF-A-mediated mechanism, and, thus contribute to tumorigenicity. Here, we propose to evaluate the oncogenic function of FoxM1 in cooperation with p53 tumor suppressor gene in oncogenesis of neural stem cells;and the essential role of FoxM1 in maintaining the characteristics of glioma stem-like cells. If the Specific Aims of this grant application are completed, not only will we understand a new mechanism of GBM molecular oncogenesis through abnormal maintenance of GBM-derived cancer "stem" cell self-renewal via FoxM1 expression, but also will we learn whether FoxM1 can serve as potential therapeutic targets. This information will have potentially high translational impact. In the long term, our study may lead to the validation of molecular targets that can be used in designing effective strategies to control this deadly disease in clinics. PUBLIC HEALTH RELEVANCE: The mean survival duration of patients with glioblastoma multiforme (GBM), the most common form of glioma, is approximately 1 year and there is no effective therapy to date. If the Specific Aims of this grant application are completed, not only will we understand a new mechanism of GBM tumorigenesis through abnormal maintenance of GBM-derived cancer "stem" cell self-renewal via FoxM1, but we will also learn whether FoxM1 or its target PDGF-A can function as potential therapeutic targets. This information will have potential translational impact. In the long term, our study may lead to the identification of molecular targets that can be used in designing effective strategies to control this deadly disease.

DESCRIPTION (provided by applicant): Malignant glioma, the most common primary brain tumor subtype, is aggressive and neurologically destructive. The mean survival duration of patients with glioblastoma multiforme (GBM), the most common form of glioma, is approximately 1 year and there is no effective therapy to date. The lack of progress can be attributed, at least in part, to the highly cellular proliferation and invasive. Thus, even after aggressive multimodal therapy, the invading GBM cells can escape the therapy and cause a tumor relapse. However, little is known about the cellular and molecular mechanisms underlying uncontrolled cellular proliferation and invasion of GBM. Based on our recent experimental results, we propose to evaluate the novel hypothesis that FoxM1, which is abnormally expressed in human GBM, causes the cellular proliferation and invasion of GBM cells, possibly through a b-catenin-mediated mechanism, and, thus contribute to tumorigenicity. To test this hypothesis, we propose to evaluate the function of FoxM1 in the cooperation with b-catenin in the expression of b-catenin target genes;the function of FoxM1-b-catenin interaction in cell proliferation and invasion of glioma cells;and the essential role of FoxM1-b-catenin interaction in maintaining the tumorigenicity of GBM cells. Moreover, we propose to determine the role of Wnt signaling pathway in the FoxM1 overexpression in GBM. If the Specific Aims of this grant application are completed, not only will we understand new mechanisms for the dysregulated b-catenin activation in general and in glioma, and for gliomagenesis through dysregulated b-catenin and FoxM1 expression/function, but also will we learn whether FoxM1 can serve as a potential therapeutic target. This information will have potentially high translational impact. In the long term, our study may lead to the validation of molecular targets that can be used in designing effective strategies to control this deadly disease in clinics. PUBLIC HEALTH RELEVANCE: The mean survival duration of patients with glioblastoma multiforme (GBM), the most common form of glioma, is approximately 1 year and there is no effective therapy to date. If the Specific Aims of this grant application are completed, not only will we understand a new mechanism of GBM tumorigenesis through abnormal cell growth and invasion of GBM cells controlled by the interaction of FoxM1 and b-catenin, but we will also learn whether FoxM1 or its target b-catenin can function as potential therapeutic targets. This information will have potential translational impact. In the long term, our study may lead to the identification of molecular targets that can be used in designing effective strategies to control this deadly disease.

DESCRIPTION (provided by applicant): Gliomas are aggressive, highly invasive, and easily become resistant to chemotherapy and radiotherapy. The mean survival duration of patients with glioblastoma multiforme (GBM), the most common form of glioma, is approximately 1 year and there is no effective therapy to date. It is the highly invasive and proliferative nature of GB rendering the tumor relapse and incurable. The molecular changes leading to this malignant behavior are poorly understood. The goal of this proposal is to gain definitive knowledge on the causative pathways and their mechanistic integration underlying GBM growth and invasion, which is critical for developing effective therapeutic modalities for GBM patients. Previous studies have shown that increased expression of FoxM1 is one of the most frequent alterations in GBM. Our recent study has shown that the level of FoxM1 protein expression in human glioblastoma tissues is inversely correlated with patient survival. Moreover, FoxM1 appears to be essential to glioma growth. However, the underlying mechanisms for FoxM1 overexpression are unknown. Therefore, we propose to investigate the molecular mechanisms underlying the dysregulated FoxM1 expression in GBM (Aim 1). We will determine whether the aberrant Wnt/b-catenin pathway activation causes FoxM1 overexpression in GBM cells. Previous studies have indicated that constitutive activation of b-catenin is not due to inactivation of the tumor suppressor APC or mutations in b-catenin. To investigate the causes for the activation of b-catenin/TCF-mediated transcription in GBM, we will determine the role and mechanisms of nuclear FoxM1 in enhancing b-catenin/TCF4/LEF-1 transcriptional activity (Aim 2). Furthermore, Stat3 pathway is a nodal hub of gliomagenesis, while the mechanisms underlying its elevated expression and activation are unknown. Our preliminary data indicated that FoxM1 overexpression causes the dysregulated Stat3 expression and activation in GBM cells, possibly through a b-catenin-mediated mechanism. Therefore, we propose to determine the regulation of Stat3 by nuclear FoxM1 and its function in FoxM1-promoted tumor development (Aim 3). If the specific aims of this grant application are completed, not only we will understand new mechanisms for the signaling integration of those major pathways, but also we will learn the biological and clinical impacts of the signaling integration on glioma development and progression. In the long term, our study may lead to the validation of molecular targets that can be used in designing effective strategies to control this deadly disease in clinics. Therefore, the findings from our proposed studies will contribute to a better understanding of the molecular mechanisms of glioma development and progression and help identify potential targets for novel therapeutic strategies against malignant glioma.

? DESCRIPTION (provided by applicant): Gliomas are aggressive, highly invasive, and resistant to chemotherapy and radiotherapy. The mean survival duration of patients with glioblastoma (GBM), the most malignant form of glioma, is approximately one year and there is no effective therapy to date. The highly invasive and proliferative nature of GBM renders the tumor relapse and incurable. The molecular changes leading to this malignant behavior are poorly understood. The goal of this proposal is to gain definitive knowledge on the causative pathways and their mechanistic integration underlying GBM growth and invasion, which are critical for developing effective therapeutic modalities for GBM patients. Specifically, the studie outlined in this proposal will directly determine the role of epigenetics in IDH1 wild-type GBM pathogenesis by dissecting the functions of tumor cell-intrinsic KDM4C, a histone demethylase. Previous studies have shown that Wnt/?-catenin signaling is critical for cancer cell proliferation invasion and cancer formation, whereas little is known about the epigenetic regulation of this pathway. First, we propose to investigate the role and mechanisms of KDM4C in enhancing Wnt/?-catenin transcriptional function (Aim 1). The studies in this Aim will uncover a novel mechanism for the persistent activation of ?-catenin-mediated transcription in GBMs. Second, we propose to evaluate the function of KDM4C expression on cell proliferation, invasion and tumorigenicity of GBM cells (Aim 2). We will also examine the therapeutic effect of inhibition of KDM4C in an animal model. Third, as the field of histone demethylase is still young, relatively little is known about the mechanisms that regulate histone demethylase. KDM4C is commonly overexpressed in most human tumors, including GBM, while the molecular mechanisms for its overexpression remain unknown. Therefore, we propose to investigate the molecular mechanisms underlying the dysregulated KDM4C expression in GBM (Aim 3). If the studies of those specific aims are completed, not only will we understand new mechanisms for the signaling integration of those major pathways, but also we will learn the biological and clinical impacts of the epigenetics regulation on glioma development and progression. In the long term, our study may lead to the validation of molecular targets that can be used in designing effective strategies to control this deadly disease in clinics. Therefore, the findings from our proposed studies will contribute to a better understanding of the molecular mechanisms of glioma development and progression and help identify potential targets for novel therapeutic strategies against malignant glioma.

Project Summary While the impact of protein ubiquitination has been extensively studied in regulating functional protein- protein interaction, protein subcellular localization and protein stability, the interplay between the ubiquitination and epigenetic machinery in orchestrating EGFR signaling in gliomagenesis has not been drawn our attention until recently. This project targets the new aspects of the ubiquitin-pathway in regulating histone H2A that in turn modulates EGFR signaling pathway in gliomagenesis. Monoubiquitination of histone H2A is one of the most abundant histone posttranslational modifications in mammalian cells. H2A ubiquitination represents an important mechanism for many regulatory transcriptional programs. Accumulating evidence supports a role of H2A ubiquitination in glioblastoma. However, how H2A ubiquitination is regulated in glioblastoma is unknown. Studies outlined in this proposal will exam the functions and mechanisms of an EGFR induced lncRNA, Lnc-EPAT, in H2A ubiquitination and tumorigenesis of glioblastoma. We will use a variety of molecular and cell-based assays, and animal models, to determine 1) whether the aberrant EGFR activation causes Lnc-EPAT overexpression in glioblastoma and the mechanisms underlying EGFR signaling-induced Lnc-EPAT expression; 2) the role and mechanisms for Lnc-EPAT in sustaining H2A ubiquitination and epigenetic regulation of EGFR pathway; 3) the functional significance and mechanisms of EGFR- Lnc-EPAT-H2Aub in glioblastoma tumorigenesis. Finally, we will determine the clinical significance of our findings using human tumor specimens. We predict that completion of these studies will contribute to a better understanding of the molecular mechanisms for H2A ubiquitination and glioblastoma tumorigenesis. Furthermore, accomplishing our goals is highly relevant to the development of novel therapeutic agents that inhibit Lnc-EPAT for better combating glioblastoma. Thus, our studies may revolutionize our understanding and treating glioblastoma.

Project Summary While the impact of protein ubiquitination has been extensively studied in regulating functional protein- protein interaction, protein subcellular localization and protein stability, the interplay between the ubiquitination and epigenetic machinery in orchestrating EGFR signaling in gliomagenesis has not been drawn our attention until recently. This project targets the new aspects of the ubiquitin-pathway in regulating histone H2A that in turn modulates EGFR signaling pathway in gliomagenesis. Monoubiquitination of histone H2A is one of the most abundant histone posttranslational modifications in mammalian cells. H2A ubiquitination represents an important mechanism for many regulatory transcriptional programs. Accumulating evidence supports a role of H2A ubiquitination in glioblastoma. However, how H2A ubiquitination is regulated in glioblastoma is unknown. Studies outlined in this proposal will exam the functions and mechanisms of an EGFR induced lncRNA, Lnc-EPAT, in H2A ubiquitination and tumorigenesis of glioblastoma. We will use a variety of molecular and cell-based assays, and animal models, to determine 1) whether the aberrant EGFR activation causes Lnc-EPAT overexpression in glioblastoma and the mechanisms underlying EGFR signaling-induced Lnc-EPAT expression; 2) the role and mechanisms for Lnc-EPAT in sustaining H2A ubiquitination and epigenetic regulation of EGFR pathway; 3) the functional significance and mechanisms of EGFR- Lnc-EPAT-H2Aub in glioblastoma tumorigenesis. Finally, we will determine the clinical significance of our findings using human tumor specimens. We predict that completion of these studies will contribute to a better understanding of the molecular mechanisms for H2A ubiquitination and glioblastoma tumorigenesis. Furthermore, accomplishing our goals is highly relevant to the development of novel therapeutic agents that inhibit Lnc-EPAT for better combating glioblastoma. Thus, our studies may revolutionize our understanding and treating glioblastoma.