TY  - JOUR
AU  - Tehranian, Cedric
AU  - Fankhauser, Laura
AU  - Harter, Patrick
AU  - Ratcliffe, Colin D H
AU  - Zeiner, Pia S
AU  - Messmer, Julia M
AU  - Hoffmann, Dirk C
AU  - Frey, Katharina
AU  - Westphal, Dana
AU  - Ronellenfitsch, Michael W
AU  - Sahai, Erik
AU  - Wick, Wolfgang
AU  - Karreman, Matthia A
AU  - Winkler, Frank
TI  - The PI3K/Akt/mTOR pathway as a preventive target in melanoma brain metastasis.
JO  - Neuro-Oncology
VL  - 24
IS  - 2
SN  - 1523-5866
CY  - Oxford
PB  - Oxford Univ. Press
M1  - DKFZ-2021-01515
SP  - 213–225
PY  - 2022
N1  - #EA:B320#LA:B329# / Volume 24, Issue 2, February 2022, Pages 213–225
AB  - Brain metastases (BM) are a frequent complication of malignant melanoma (MM), with limited treatment options and poor survival. Prevention of BM could be more effective and better tolerated than treating established BM in various conditions.To investigate the temporo-spatial dynamics of PI3K/Akt/mTOR (PAM) pathway activation during BM formation and the preventive potential of its inhibition, in vivo molecular imaging with an Akt biosensor was performed, and long-term intravital multiphoton microscopy through a chronic cranial window in mice.In vivo molecular imaging revealed invariable PAM pathway activation during the earliest steps of brain colonization. In order to perform a long-term intravascular arrest and to extravasate, circulating MM cells needed to activate their PAM pathway during this process. However, the PAM pathway was quite heterogeneously activated in established human brain metastases, and its inhibition with the brain-penetrant PAM inhibitor GNE-317 resulted in only modest therapeutic effects in mice. In contrast, giving GNE-317 in preventive schedules that included very low doses effectively reduced growth rate and number of BM in two MM mouse models over time, and led to an overall survival benefit. Longitudinal intravital multiphoton microscopy found that the first, rate-limiting steps of BM formation - permanent intravascular arrest, extravasation, and initial perivascular growth - are most vulnerable to dual PI3K/mTOR inhibition.These findings establish a key role of PAM pathway activation for critical steps of early metastatic brain colonization and reveal its pharmacological inhibition as a potent avenue to prevent the formation of clinically relevant BM.
KW  - PI3K/Akt/mTOR pathway (Other)
KW  - brain metastasis (Other)
KW  - dual PI3K/mTOR inhibition (Other)
KW  - extravasation (Other)
KW  - tertiary prevention (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:34216217
DO  - DOI:10.1093/neuonc/noab159
UR  - https://inrepo02.dkfz.de/record/169708
ER  -