Learn more about the work being done by our faculty in their labs below.
Cancer stem cell biology, cellular signaling and therapy responses in human brain tumors, in particular, glioblastoma (GBM)
Integrated genomic analysis by TCGA revealed tat GBMs can be classified into four clinically relevant subtypes, proneural (PN), neural, mesenchymal (Mes) and classical GBMs with each characterized by distinct gene expression signatures and genetic alterations. We reported that PN and Mes glioma stem cells (GSCs) subtypes also have distinct dysregulated signaling pathways. Our current research focuses on novel mechanisms/cellular signaling of GSC biology, tumorigenesis, progression, invasion/metastasis, angiogenesis and therapy responses of GSCs and GBMs.
1. MicroRNAs (miRs) and non-coding RNAs in GSCs and GBMs – miRs and other small non-coding RNAs act as transcription repressors or inducers of gene expression or functional modulators in all multicellular organisms. Dysregulated miRs/noncoding RNAs plays critical roles in cancer initiation, progression and responses to therapy. We study the mechanisms by which deregulated expression of miRs influence GBM malignant phenotypes through interaction with signaling pathways, that in turn, influence proneural (PN)- and mesenchymal (Mes)-associated gene expression in GSCs and GBM phenotypes. We study the molecular consequences and explore clinical applications of modulating miRs and signaling pathways in GBMs. We are establishing profiles of non-coding RNAs in these GSCs and study mechanisms and biological influences of these non-coding RNAs in regulating GSC biology and GBM phenotypes. In addition, we explore novel therapeutic approaches of delivery of tumor suppressive miRs into GSC brain xenografts in animals.
2. Autophagy in GBMs. (Macro)autophagy is an evolutionally conserved dynamic process whereby cells catabolize damaged proteins and organelles in a lysosome-dependent manner. Autophagy principally serves as an adaptive role to protect cells and tissues, including those associated with cancer. Autophagy in response to multiple stresses including therapeutic treatments such as radiation and chemotherapies provides a mechanism for tumor cell to survive and acquire resistance to therapies. Tumors can use autophagy to support and sustain their proliferation, survival, metabolism, invasiveness, metastasis and resistance to therapy. We study mechanisms by which phosphorylation, acetylation and ubiquitination of autophagy proteins regulate GSC and GBM phenotypes and autophagic response, which, in turn contributes to tumor cell survival, growth and resistance to therapy. We investigate whether disruption of these post-translational processes on autophagy proteins inhibits autophagy and enhances the efficacy of combination therapies for GBMs. We examine whether cross-talks between miRs, autophagy and oncogenic signaling pathways regulate GSC stemness and phenotypes.
3. Heterogeneity, epigenetic regulation, DNA damage and metabolic pathways in GSCs and GBMs. Intratumoral heterogeneity is a characteristic of GBMs and most of cancers. Phenotypic and functional heterogeneity arise among GBM cells within the same tumor as a consequence of genetic change, environmental differences and reversible changes in cell properties. Subtype mosaicism within the same tumor and spontaneous conversion of human PN to Mes tumors have been observed in clinical GBMs. We explore an emerging epigenetic marker with distinct functions such as DNA methylation together with genetic mapping of these markers to assess their contributions to GBM heterogeneity. In addition, compared with PN GSCs, DNA damage and glycolytic pathways are aberrant active in Mes GSCs. We investigate the mechanisms by which these pathways regulate GSC and GBM phenotypes and responses to therapies.
4. Oncogenic receptor tyrosine kinase (RTKs) signaling, small Rho GTPase regulators in GBM and GSCs: Small Rho GTPases such as Rac1 and Cdc42 modulate cancer cell migration, invasion, growth and survival. Recently, we described mechanisms by which EGFR and its mutant EGFRvIII and PDGFR alpha promote glioma growth and invasion by distinct mechanisms involving phosphorylation of Dock180, a Rac-specific guanidine nucleotide exchange factor (GEF) and DCBLD2, an orphan membrane receptor. We are currently investigating involvement of other modulators/GEFs and other Rho GTPases in modulating GSC and GBM phenotypes and responses to therapy.
View Dr. Cheng's complete list of publications in PubMed.
Shi-Yuan Cheng, PhD at 312-503-5314
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Defining and targeting the oncogenome of Glioblastoma.
Our research program is aimed at understanding the genetic program that underlies the pathogenesis of Glioblastoma multiforme (GBM), the most prevalent and malignant form of brain cancer. Applying a combination of cell/molecular biology, oncogenomic and mouse engineering approaches, we are dedicated to systematically characterize novel gliomagenic oncogenes and tumor suppressors. We will functionally delineate and validate these pathways using cell culture and animal models and develop novel nanotechnological approaches to target these aberrations in established tumors.
View Dr. Stegh's full list of publications at PubMed
Alexander Stegh, MD, PhD, at 312-503-2879