Signaling pathways and inhibitors of cells from patients with kaposiform lymphangiomatosis

Abstract

Background Kaposiform lymphangiomatosis (KLA) is a rare lymphatic anomaly with significant morbidity and mortality. KLA is characterized by diffuse multifocal lesions comprised of focal areas of “kaposiform” spindled cells accompanying malformed lymphatic channels. The goal of this study was to identify activated signaling pathways in cells isolated from three KLA patients for the purpose of testing new therapies. Procedure Cells were obtained from the lungs of one patient isolated at autopsy and the spleen of two patients removed in surgery due to disease complications. A protein kinase array was performed on the KLA cell lysates and normal lymphatic endothelial cells. Results Higher activation of key signaling pathways in the KLA cells, including PRAS40, AKT1/2/3, and ERK‐1/2, was identified by protein kinase array and confirmed by Western blot analysis. This indicated a role for highly activated PI3K–AKT and MAPK–ERK‐1/2 signaling pathways in KLA cells. Cell proliferation studies assessed PI3K inhibitors (LY294002; BYL719), AKT inhibitor ARQ092, mTOR inhibitor rapamycin, and MAPK inhibitor U0126. These studies demonstrated that PI3K–AKT–mTOR and MAPK signaling are important mediators of KLA cell proliferation. BYL719 and rapamycin were more effective at inhibiting KLA cell proliferation than U0126. Conclusions Our studies using cells from KLA patient lesions demonstrate that these cells are highly proliferative and the PI3K–AKT–mTOR and MAPK pathways are promising therapeutic targets. Development and clinical trials of PI3K, AKT, and MAPK inhibitors for cancer treatment and the data in this study lend support for early clinical trials assessing the efficacy of these inhibitors in KLA patients.

Low dose AKT inhibitor miransertib cures PI3K-related vascular malformations in preclinical models of human disease

“…In this regard, we demonstrate that miransertib similarly impairs cell viability of PIK3CA-and TEK-mutant ECs derived from patients. This is in line with previous studies reporting the effect of miransertib in PIK3CA-mutant endothelial cells (Boscolo et al, 2019). Our results might indicate that this therapy is also effective for TEK-mutant vascular malformations; however, the lack of TEK-mutant mouse lines precludes the assessement in vivo.…”

Characterization of kaposiform lymphangiomatosis tissue‐derived cells

“…We used immunocytochemical staining and cell morphology to identify the cell types isolated from clinical specimens. KLA cells showed spindle‐shaped morphology (Figure 1) and stained positive for D2‐40 (Figure 2), as previously reported 7,8 . The tube formation assay showed that the ability of KLA cells to form capillary‐like structures (Figure 3B,C) was markedly less than that of HDLEC ( p < .01, Figure 3D).…”

“…Experimental models, such as patient‐derived cells, are invaluable tools in preclinical studies. However, KLA patient‐derived cells have only been isolated from a few patients since this disease was first identified as KLA 7,8 …”

Sirolimus in the treatment of kaposiform lymphangiomatosis

“…Most recently, several studies detected the NRAS p. Q61R mutations in most patients with KLA [ 16 , 17 ]. There is evidence suggesting that NRAS mutations are associated with cell proliferation through the MAPK and PI3K/AKT signaling pathways [ 18 ]. Similar to other vascular anomalies caused by mutations, NRAS somatic mutations may contribute to the occurrence of KLA.…”

“…Recent studies have proven that sirolimus has promising potential in the treatment of complicated vascular anomalies [ 1 , 7 – 9 ]. An in vitro experiment suggested that the PI3K/AKT and MAPK pathways are candidate therapeutic targets for KLA and that sirolimus could effectively inhibit KLA-derived cell proliferation [ 18 ]. Some experts recommend sirolimus combined with steroids and/or vincristine to treat KLA, but the relevant data are scarce.…”