caa a22 4500 555285286 20200410031629.0 cr unu---uuuuu 190206s2018 xx s 000 0 eng 1932-6203 10.1371/journal.pone.0200343 doi (BORIS)oai:boris.unibe.ch:124288 610 ddc 29985963 pmid PIK3CA mutations are specifically localized to lymphatic endothelial cells of lymphatic malformations [Elektronische Daten] [Hannah Blesinger, Silke Kaulfuß, Thiha Aung, Sonja Schwoch, Lukas Prantl, Jochen Karl Rössler, Jörg Wilting, Jürgen Becker] publishedVersion openAccess eu-repo Lymphatic malformations (LM) are characterized by the overgrowth of lymphatic vessels during pre- and postnatal development. Macrocystic, microcystic and combined forms of LM are known. The cysts are lined by lymphatic endothelial cells (LECs). Resection and sclerotherapy are the most common treatment methods. Recent studies performed on LM specimens in the United States of America have identified activating mutations in the phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) gene in LM. However, whole tissue but not isolated cell types were studied. Here, we studied LM tissues resected at the University Hospitals Freiburg and Regensburg, Germany. We isolated LECs and fibroblasts separately, and sequenced the commonly affected exons 8, 10, and 21 of the PIK3CA gene. We confirm typical monoallelic mutations in 4 out of 6 LM-derived LEC lines, and describe two new mutations i.) in exon 10 (c.1636C>A; p.Gln546Lys), and ii.) a 3bp in-frame deletion of GAA (Glu109del). LM-derived fibroblasts did not possess such mutations, showing cell-type specificity of the gene defect. High activity of the PIK3CA-AKT- mTOR pathway was demonstrated by hyperphosphorylation of AKT-Ser473 in all LM-derived LECs (including the ones with newly identified mutations), as compared to normal LECs. Additionally, hyperphosphorylation of ERK was seen in all LM-derived LECs, except for the one with Glu109del. In vitro, the small molecule kinase inhibitors Buparlisib/BKM-120, Wortmannin, and Ly294002, (all inhibitors of PIK3CA), CAL-101 (inhibitor of PIK3CD), MK-2206 (AKT inhibitor), Sorafenib (multiple kinases inhibitor), and rapamycin (mTOR inhibitor) significantly blocked proliferation of LM-derived LECs in a concentration-dependent manner, but also blocked proliferation of normal LECs. However, MK-2206 appeared to be more specific for mutated LECs, except in case of Glu109 deletion. In sum, children that are, or will be, treated with kinase inhibitors must be monitored closely. Blesinger Hannah joint author Kaulfuß Silke joint author Aung Thiha joint author Schwoch Sonja joint author Prantl Lukas joint author Rössler Jochen Karl joint author Wilting Jörg joint author Becker Jürgen joint author PLoS ONE 13(7), e0200343 1932-6203 https://boris.unibe.ch/124288/1/journal.pone.0200343.pdf text/html WWW-Backlink auf das Repository 1 info:eu-repo/semantics/article boris PeerReviewed boris peerstatus BORIS 856 40 https://boris.unibe.ch/124288/1/journal.pone.0200343.pdf text/html WWW-Backlink auf das Repository BORIS 700 1- Blesinger Hannah joint author BORIS 700 1- Kaulfuß Silke joint author BORIS 700 1- Aung Thiha joint author BORIS 700 1- Schwoch Sonja joint author BORIS 700 1- Prantl Lukas joint author BORIS 700 1- Rössler Jochen Karl joint author BORIS 700 1- Wilting Jörg joint author BORIS 700 1- Becker Jürgen joint author BORIS 773 0- PLoS ONE 13(7), e0200343 1932-6203 BK010053 XK010053 XK010000 BORIS BORIS BORIS info:eu-repo/semantics/article openAccess