Membrane-anchored b-glucuronidase

1
Membrane-anchored b-glucuronidase
Steve Roffler
Institute of Biomedical Sciences Academia
Sinica Taipei, Taiwan
2
Memzyme activation of imaging or therapeutic
agents
Potential advantage Signal amplification due to
enzymatic hydrolysis of glucuronide probes or
drugs
3
Potential advantages of a ßG reporter
ßG in lysosomes inaccessible to glucuronides
Low serum ßG little systemic activation Low
toxicity Fast renal clearance rapid
imaging Endogenous - low immunogenicity Many
possible glucuronide probes and drugs
4
In vitro imaging of gene expression
red enzyme expression
green activated probe accumulation
Fluorescent probe can be activated and
accumulate at cells that express enzyme
5
Imaging of adenovirus memzyme expression
Kodak IS2000MM
Sites of Ad transgene expression could be imaged
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In vitro activation of HAMG
HAMG Glucuronide prodrug
pHAM Active drug
COOH
O
Cl
HO
Cl
O
N
HO
HO
N
Cl
OH
Cl
HAMG can be activated at EJ/mßG cells
7
HAMG prodrug toxicity to mice
HAMG is well tolerated by mice
8
Prodrug therapy of EJ tumors
(150 mg/kg HAMG on days 15 and 19)
2000
EJ PBS
EJ HAMG
EJ/mßG PBS
EJ/mßG HAMG
1000
Tumor volume (mm3)
0
0
10
20
30
40
50
Days
HAMG displayed selective activity against EJ/mßG
tumors
9
Summary
Surface enzyme allow both imaging and
therapy Immunogenicity is low but selectivity is
high May possess advantages for cancer gene
therapy
10
Surface expression
Dr. Tian-Lu Cheng Kaohsiung Medical University
T cell activation
Tang-Bi Liu
Shih-en Chang
Wen-Jun Chung
Chin-Chuan Chen
Pei-Yu Wu
Dr. Hsin-Ell Wang National Yang Ming University
Yi-Hsuan Chiang
Chien-I Su
Dr. Yu-Ling Leu Chia-Nan College of Pharmacy
and Science
Surface scFv
Dr. Kuang-Wen Liao
Shey-Cherng Tzo
Dr. Ji-Wang Chern National Taiwan University
Bing-Mae Chen
http//www.ibms.sinica.edu.tw/sroff/sr_refs.html