Project Grant F31CA301899

CHARACTERIZING AND TARGETING MEMBRANE PROPERTIES TIED TO CHEMOTHERAPEUTIC RESISTANCE IN GLIOMAS - PROJECT SUMMARY GLIOBLASTOMA, ASTROCYTOMA, AND OLIGODENDROGLIOMA COMPRISE A CLASS OF AGGRESSIVE AND DEADLY BRAIN TUMORS CALLED DIFFUSE GLIOMAS. THE 5-YEAR SURVIVAL RATE OF GLIOBLASTOMA PATIENTS IS AS LOW AS 8% AS GLIOMAS REMAIN DIFFICULT TO TREAT DUE TO TUMOR CELLS THAT DEVELOP RESISTANCE TO THE STANDARD CHEMOTHERAPY TEMOZOLOMIDE (TMZ). THUS, IT IS IMPERATIVE TO CHARACTERIZE AND TARGET TMZ-RESISTANT CELLS TO TREAT GLIOMAS MORE EFFECTIVELY FOR IMPROVED PATIENT OUTCOME AND SURVIVAL. CURRENTLY, KNOWN TMZ RESISTANCE MECHANISMS INCLUDE ABERRANT DNA REPAIR ENZYMES AND INCREASED DRUG EFFLUX. HOWEVER, OUR RECENT DATA SHOW THAT MEMBRANE COMPONENTS MAY ALSO PLAY A KEY ROLE. OUR LAB HAS DEVELOPED A NOVEL MEMBRANE-SENSITIVE CELL SORTING TECHNIQUE ENABLING US TO SUCCESSFULLY SORT TMZ-RESISTANT CELLS FROM VARIOUS TYPES OF GLIOMA. WITH THIS UNIQUE ADVANTAGE, MY FIRST AIM IS TO CHARACTERIZE THE MOLECULAR PROFILE OF TMZ-RESISTANT GLIOMA CELLS USING SINGLE-CELL RNA SEQUENCING AND MICROARRAYS. I ANTICIPATE MY TRANSCRIPTOMIC ANALYSES WILL YIELD DIFFERENTIAL EXPRESSION OF MEMBRANE-RELATED GENES IN THE TMZ-RESISTANT CELL POPULATION THAT MAY SERVE AS NOVEL BIOMARKERS OF RESISTANCE AND TARGETS FOR TREATMENT. SINCE RESISTANT GLIOMA CELLS CAN BE SORTED BASED ON MEMBRANE DIFFERENCES, GLYCOSYLATION MAY PLAY A MAJOR ROLE IN MEDIATING TMZ RESISTANCE AS IT CONSTITUTES A SIGNIFICANT MEMBRANE MODIFICATION. GLYCOSYLATION IS THE POST-TRANSLATIONAL ADDITION OF GLYCANS (SUGARS) TO MEMBRANE PROTEINS AND LIPIDS; IT REGULATES THE FUNCTION OF VARIOUS MEMBRANE PROTEINS, INCLUDING DRUG TRANSPORTERS, GROWTH FACTORS, AND CELL ADHESION PROTEINS. WE FOUND THAT TMZ-RESISTANT CELLS DIFFER IN THEIR GLYCOSYLATION PROFILE AND THAT BLOCKING THE N-GLYCAN BRANCHING PATHWAY DECREASED TMZ RESISTANCE. GIVEN THIS DYNAMIC RELATIONSHIP BETWEEN GLYCOSYLATION AND RESISTANCE, MY SECOND AIM IS TO INVESTIGATE THE FUNCTIONAL CONSEQUENCES OF PHARMACOLOGICALLY ALTERING GLIOMA CELL GLYCOSYLATION. I WILL ASSESS THE EFFECTS ON TMZ RESISTANCE, CELL VIABILITY, PROLIFERATION, ADHESION, AND DRUG TRANSPORTER FUNCTION, AS THIS WILL PROVIDE INSIGHT INTO THE INTERPLAY BETWEEN GLYCOSYLATION, MEMBRANE PROPERTIES, AND TMZ RESISTANCE MECHANISMS. TO ASSESS THE CLINICAL APPLICATION OF THESE GLYCOSYLATION MODIFICATIONS AS A SUPPLEMENT TO TMZ, IN MY THIRD AIM I WILL TEST THESE TREATMENT STRATEGIES IN A PATIENT-DERIVED XENOGRAFT GLIOMA MOUSE MODEL TO MONITOR THE EFFECTS ON ANIMAL SURVIVAL AND ANALYZE THE BRAIN TISSUE FOR HISTOLOGY AND TUMOR SIZE ASSESSMENT. MY PROJECT'S OVERALL GOAL IS TO DISTINGUISH UNIQUE MEMBRANE CHARACTERISTICS OF TMZ-RESISTANT GLIOMA CELLS AND DETERMINE THE POTENTIAL CLINICAL BENEFITS OF MANIPULATING MEMBRANE PROPERTIES IN ORDER TO IMPROVE THE EFFICACY OF CURRENT STANDARD GLIOMA TREATMENTS. TO SUPPORT MY UNDERTAKING OF THIS PROJECT AND CAREER DEVELOPMENT, I WILL ENROLL IN SCIENTIFIC COURSES AND SKILLS TRAINING, TAKE ON TEACHING ROLES, PRESENT MY RESEARCH, AND DEVELOP FIRST-AUTHORED MANUSCRIPTS. UC IRVINE IS A COLLABORATIVE ENVIRONMENT AND WILL FOSTER MY CONNECTION TO FACULTY MENTORS WITH EXTENSIVE EXPERTISE THAT WILL SUPPORT MY GROWTH TOWARD A PRINCIPAL INVESTIGATOR CAREER.