Elsevier

Neoplasia

Volume 18, Issue 8, August 2016, Pages 500-511
Neoplasia

Inhibition of Rho-Associated Kinase 1/2 Attenuates Tumor Growth in Murine Gastric Cancer1,2

https://doi.org/10.1016/j.neo.2016.07.002Get rights and content
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Abstract

Gastric cancer (GC) remains a malignant disease with high mortality. Patients are frequently diagnosed in advanced stages where survival prognosis is poor. Thus, there is high medical need to find novel drug targets and treatment strategies. Recently, the comprehensive molecular characterization of GC subtypes revealed mutations in the small GTPase RHOA as a hallmark of diffuse-type GC. RHOA activates RHO-associated protein kinases (ROCK1/2) which regulate cell contractility, migration and growth and thus may play a role in cancer. However, therapeutic benefit of RHO-pathway inhibition in GC has not been shown so far. The ROCK1/2 inhibitor 1-(5-isoquinoline sulfonyl)-homopiperazine (HA-1077, fasudil) is approved for cerebrovascular bleeding in patients. We therefore investigated whether fasudil (i.p., 10 mg/kg per day, 4 times per week, 4 weeks) inhibits tumor growth in a preclinical model of GC. Fasudil evoked cell death in human GC cells and reduced the tumor size in the stomach of CEA424-SV40 TAg transgenic mice. Small animal PET/CT confirmed preclinical efficacy. Mass spectrometry imaging identified a translatable biomarker for mouse GC and suggested rapid but incomplete in situ distribution of the drug to gastric tumor tissue. RHOA expression was increased in the neoplastic murine stomach compared with normal non-malignant gastric tissue, and fasudil reduced (auto) phosphorylation of ROCK2 at THR249 in vivo and in human GC cells in vitro. In sum, our data suggest that RHO-pathway inhibition may constitute a novel strategy for treatment of GC and that enhanced distribution of future ROCK inhibitors into tumor tissue may further improve efficacy.

Abbreviations

GC
gastric cancer
CEA
carcinoembryonic antigen
FASU
fasudil
FTICR
fourier transform ion cyclotron resonance
MALDI-MSI
matrix-assisted laser desorption/ionization mass spectrometry imaging
MAPK
mitogen-activated protein kinase
MLC
myosin light chain
PET/CT
positron emission/computer tomography
ROCK
Rho-associated kinase
SV40
simian virus 40
TAg
large T-Antigen
WB
Western blot
WT
wild-type

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1

Financial support: This study was supported by a grant to E.B. from the Deutsche Forschungsgemeinschaft (DFG BU2285) and to C.H. from the German Federal Ministry of Education and Research (17001X11 and 03FH018IN4) and from Baden-Württemberg Ministry of Science and Culture “ZAFH ABIMAS” (ZO IV and EFRE funding). This work was also funded by the BMBF (Project M2oBiTE “Molecular Bioanalytics and Theranostics” 13GW0091B to C.H. and 13GW0091E to B.W.) and the DFG (Project Small Animal PET/CT INST 91027/11). M.E. received funding from ZOBEL (Center of Geriatric Biology and Oncology) and Land Baden-Württemberg (Perspektivförderung).

2

Disclosure of Potential Conflicts of Interest: J.F. is an employee of Bruker Daltonik GmbH. No potential conflicts of interest exist for the other authors.

3

Equal author contribution.