Dataset Information

AKT hyper-phosphorylation associated with PI3K mutations in lymphatic endothelial cells from a patient with lymphatic malformation.

ABSTRACT: Lymphatic malformations (LM) are characterized by abnormal formation of lymphatic vessels and tissue overgrowth. The lymphatic vessels present in LM lesions may become blocked and enlarged as lymphatic fluid collects, forming a mass or cyst. Lesions are typically diagnosed during childhood and are often disfiguring and life threatening. Available treatments consist of sclerotherapy, surgical removal and therapies to diminish complications. We isolated lymphatic endothelial cells (LM-LEC) from a surgically removed microcystic LM lesion. LM-LEC and normal human dermal-LEC (HD-LEC) expressed endothelial (CD31, VE-Cadherin) as well as lymphatic endothelial (Podoplanin, PROX1, LYVE1)-specific markers. Targeted gene sequencing analysis in patient-derived LM-LEC revealed the presence of two mutations in class I phosphoinositide 3-kinases (PI3K) genes. One is an inherited, premature stop codon in the PI3K regulatory subunit PIK3R3. The second is a somatic missense mutation in the PI3K catalytic subunit PIK3CA; this mutation has been found in association with overgrowth syndromes and cancer growth. LM-LEC exhibited angiogenic properties: both cellular proliferation and sprouting in collagen were significantly increased compared with HD-LEC. AKT-Thr308 was constitutively hyper-phosphorylated in LM-LEC. Treatment of LM-LEC with PI3-Kinase inhibitors Wortmannin and LY294 decreased cellular proliferation and prevented the phosphorylation of AKT-Thr308 in both HD-LEC and LM-LEC. Treatment with the mTOR inhibitor rapamycin also diminished cellular proliferation, sprouting and AKT phosphorylation, but only in LM-LEC. Our results implicate disrupted PI3K-AKT signaling in LEC isolated from a human lymphatic malformation lesion.

SUBMITTER: Boscolo E

PROVIDER: S-EPMC4366356 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

AKT hyper-phosphorylation associated with PI3K mutations in lymphatic endothelial cells from a patient with lymphatic malformation.

Boscolo Elisa E Coma Silvia S Luks Valerie L VL Greene Arin K AK Klagsbrun Michael M Warman Matthew L ML Bischoff Joyce J

Angiogenesis 20141126 2

Lymphatic malformations (LM) are characterized by abnormal formation of lymphatic vessels and tissue overgrowth. The lymphatic vessels present in LM lesions may become blocked and enlarged as lymphatic fluid collects, forming a mass or cyst. Lesions are typically diagnosed during childhood and are often disfiguring and life threatening. Available treatments consist of sclerotherapy, surgical removal and therapies to diminish complications. We isolated lymphatic endothelial cells (LM-LEC) from a ...[more]

PMID: 25424831

Similar Datasets

Project description: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.

Dataset Information

AKT hyper-phosphorylation associated with PI3K mutations in lymphatic endothelial cells from a patient with lymphatic malformation.

Publications

AKT hyper-phosphorylation associated with PI3K mutations in lymphatic endothelial cells from a patient with lymphatic malformation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets