Engineered Microglia to Locate CD133+ Tumor-Initiating Cells

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1 Engineered Microglia to Locate CD133+ Tumor-Initiating Cells Purdue University igem Team Jessamine Osborne, Janie Stine, Sung Ma, Joe Bretzmann, Noah Isch, Brad Fawaz, Lukas Ly

2 Glioblastoma Multiforme Glioblastoma multiforme (GBM) Grade 4 tumor (WHO) 60% of primary brain tumors Current tumor removal methods insufficient Mean survival time with treatment: 1 year (Holland 2000)

3 The Cause? Cancer Stem-Cell Theory Reverted somatic cells or stem cells Tumor-initiating Needle in Haystack In GBM: CD133+ stemlike cells Cause of recurrence? x-glioblastoma_-mr_sagittal_with_contrast jpg

4 Our Goal: Novel Cancer Therapy Seek and destroy CD133+ glioblastoma Preliminary project: Seek and label Seek: Mobility of microglia Detect: CD133 transmembrane glycoprotein (found on stem cells) Label: tat-gfp

5 Microglia The Concept Microglia migrate towards CD133+ Microglia express glioblastoma chimeric tat-gfp Downstream diffuses Fc receptor product Glioblastoma Binding of CD133 out starts of microglia c-jun activates mrna is translated labeled by uptake signaling cascadetranscription of tatinto tat-gfp protein of tat-gfp GFP mrna Tat- GFP CD133+ Glioblastoma

6 1 Microglia migrate towards CD133+ GBM cells Chimeric Fc Receptor binds CD133, setting off a signal cascade with downstream product C-jun 2 3 Production of C-jun activates transcription of tat-gfp tat-gfp diffuses out of the microglia, entering the CD133+ GBM cell and labeling it! 4

7 Microglia Microglia Macrophages of CNS Dormant/Ramified State vs. Active State 250 um Microglia

8 1 Microglia migrate towards CD133+ GBM cells Chimeric Fc Receptor binds CD133, setting off a signal cascade with downstream product C-jun 2 3 Production of C-jun activates transcription of tat-gfp tat-gfp diffuses out of the microglia, entering the CD133+ GBM cell and labeling it! 4

9 Fc Receptors Fc Receptors Found on macrophages Accept Fc portion of antibody C-jun Downstream product of Fc γ receptor Chimeric Receptor CD133-binding Fc Receptor Invitrogen Tools; Oxyburst

10 1 Microglia migrate towards CD133+ GBM cells Chimeric Fc Receptor binds CD133, setting off a signal cascade with downstream product C-jun 2 3 Production of C-jun activates transcription of tat-gfp tat-gfp diffuses out of the microglia, entering the CD133+ GBM cell and labeling it! 4

11 CD133+ glioblastoma CD133+ Stem-Like Cells In some glioblastoma multiforme Resistant to hypoxia, irradiation, chemotherapies (Qiang, et al. 2009) 1 mm CD133+ Glioblastoma

12 1 Microglia migrate towards CD133+ GBM cells Chimeric Fc Receptor binds CD133, setting off a signal cascade with downstream product C-jun 2 3 Production of C-jun activates transcription of tat-gfp tat-gfp diffuses out of the microglia, entering the CD133+ GBM cell and labeling it! 4

13 Protein tag: tat Cell-penetrating peptide (CPP) Short peptide sequence discovered in HIV-1 GFP: green fluorescent protein Tat-GFP tat- GFP

14 1 Microglia migrate towards CD133+ GBM cells Chimeric Fc Receptor binds CD133, setting off a signal cascade with downstream product C-jun 2 3 Production of C-jun activates transcription of tat-gfp tat-gfp diffuses out of the microglia, entering the CD133+ GBM cell and labeling it! 4

15 Plasmid Design Mammalian vector CD133 Detection Response to CD133 Tat-GFP Characterization Part Number: K Wider applications

16 Why Model? Answer key questions How long until GFP is detectable? Will a stronger promoter be necessary? Modeling Predict system behavior How specific is the system? What happens when conditions are altered?

17 Assumptions and Variables Assumptions 2-D physical system State modeling Mass-action kinetics tat-gfp degradation negligible in extracellular matrix Mu, Mg Ma Variables M = Microglia G = CD133+ glioblastoma cells TG = tat-gfp G TGm, TGe, TGg

18 The Model dm u k M ( K M ) k M, dt grow m u u m u dm g k M, ( K M ) k M k M dt dg k G dt grow m g growg, g m u a g

19 The Model dm g k M grow, m g ( K M g ) k M k M G m u a g dt dm a k M ( K M ) k M G k M, dt grow m a a a g d a

20 The Model dtg dt m k k TG k TG k TG Tm diff, m m Dm m up, m e dtg e 0, M a 0 k k TG, Tm k TG ktm, M, k TG a 0, dt diff m m up g e up m e

21 The Model dtg e k TG k TG k TG diff, m m up, g e up, m e dt dtg dt g k TG k TG k TG up, g e Dg g diff, g g

22 tat-gfp (mlc/cell) Microglia/Glioblastoma (cells/um2) Simulations Critical Model Parameters: Diffusion of tat-gfp out of microglia Uptake of tat-gfp by glioblastoma Rate of synthesis of tat-gfp Parameters limit design 8 x Microglial/Glioblastoma population growth Unactivated microglia Microglia near glioblastoma Activated microglia Total microglia Glioblastoma Time (hours) tat-gfp Concentration tat-gfp in Microglia Extracellular tat-gfp tat-gfp in Glioblastoma Time (hours)

23 Select, Acquire, and Establish Cell Lines BV-2 cell line Immortalized mouse microglia Established by Dr. Bistoni (Perugia, Italy) Donated by Dr. Selkoe (Harvard Medical School) GAMB1 cell line Primary human CD133+ tumorinitiating cells Donated by Dr. Tofilon (Moffitt Cancer Center) 250 um 1 mm

24 Cell Culture Conditions Cell Name Reagent Conditions BV-2 RPMI o C 5% CO2 Gentamicin 10% Heat inactivated FBS GAMB1 D-MEM/F12 37 o C 5% CO2 B-27 supplement bfgf EGF Streptomycin

25 2D Co-Culture Microglia survive and function in stem cell media Microglia interact with GAMB1 glioblastoma 250 um

26 3D Culture Test platform to better model in vivo conditions Distinctly different morphologies in 3D environment Neurospheres 1 mm 1 mm

27 Measuring Growth Rates kgrow ~0.099/hr Doubling time ~7 hours 250 um 250 um 0 hours 19 hours

28 Flow Cytometry Original culture enriched for 98% expression of CD133 Maintain stem cell markers in culture CD133 Expression Sox 2 Expression

29 Harvest tat-gfp Protein Transform tat-gfp gene into E. coli expression bacteria Harvest with His affinity column Use tat-gfp to characterize kinetics

30 Determine kinetic parameters using bacterial tat-gfp Bifurcation analysis of model Creation & characterization of plasmids Test chimeric receptor Modify design to seek and destroy CD133+ cells Future Work

31 Main Idea: Conclusions Seek & label tumor-inducing stem cells in glioblastoma multiforme How: Microglial mobility Chimeric Fc receptor Tat-GFP Accomplishments Wider applications Modular system MMS/Advertorial/photo-5-sandvik-coromant.jpg

32 Acknowledgments Cell Lines and Plasmid Philip Tofilon, PhD (Moffitt Cancer Center) Dennis Selkoe, PhD (Harvard Medical School) Shan Gao, PhD (Columbia University) Project Advice Brian Seed, PhD (Harvard Medical School) Lou Stancato, PhD (Eli Lilly) Timmy Ding, PhD (Genscript) John Martyn, PhD (Avexa Ltd) Eric Gowan, PhD (University of Adelaide) Ray Fatig Jill Hutchcroft, PhD Charles Buck, PhD Frederick Gimble, PhD Simran Banga, PhD Funding VP of Research Oncological Science Center NIH Cancer Prevention Interdisciplinary Education Program Agricultural and Biological Engineering Nuclear Engineering Student Government Special thanks to: Indiana Biocrossroads Bindley Bioscience Center

33 Acknowledgments Special thanks to our advisors Dr. Jenna Rickus, Dr. Kari Clase, and Craig Barcus. Their support and advice has been invaluable.

34 Questions???