The mTOR Signal Pathway Is Overactivated in Human Lymphatic Malformations

Phosphatidylinositol 3-Kinase/Protein Kinase B/Mammalian Target of the Rapamycin Pathway-Related Protein Expression in Lung Squamous Cell Carcinoma and Its Correlation with Lymph Node Metastasis

The targeted therapy of lung squamous cell carcinoma (LSCC), a pathological type of non-small-cell lung cancer, is relatively lacking by contrast with lung adenocarcinoma. The overexpression or inhibition of intracellular signaling pathways leads to disease. To evaluate genes for a targeted therapy in LSCC, we analyzed PI3K pathway components in LSCC tissues and found elevated PI3K levels in LSCC tissues compared with adjacent counterparts. A comparison of PI3K levels in tissues with and without metastasis revealed that the PI3K pathway activity was greatly increased in metastatic tissues. Our findings suggest that the metastasis of cancer cells in patients with LSCC is closely related to the overexpression of PI3K pathway components in cancer tissues. We performed in vitro cell culture experiments and found that inhibition of PI3K activity decreased proliferation and increased apoptosis in H520 cells, suggesting that PI3K pathway inhibition limits LSCC cell proliferation. We hypothesize that LSCC metastasis is related to the overexpression of PI3K pathway components and inhibiting this pathway may help reduce the risk of lymph node metastasis in LSCC patients.

A somatic mutation in PIK3CD unravels a novel candidate gene for lymphatic malformation

Background

Lymphatic malformations (LMs) are benign congenital malformations that stem from the abnormal development of the lymphatic vessels during early embryogenesis. Somatic PIK3CA gene mutations are conventional cause leading to LMs. Both macrocystic and microcystic LMs arise due to lymphatic endothelial cell-autonomous defects, depending on the time in development at which PIK3CA gene mutation occurs. Recent study finds a PIK3CA mutation in 79% of LMs. However, discovering new genetic events in this disease is crucial to identify the molecular mechanism of the pathogenesis and further develop new targeted therapies.

Results

Here, we initially performed whole-exome sequencing in six children with LMs to find a new causal gene. Somatic mutations in PIK3CA (c.1633G > A [p. E545K] and PIK3CD (c.1997T > C [p.L666P]) were discovered in two different individuals. In vitro functional studies were conducted to demonstrate the pathogenicity of the novel mutation c.1997T > C in PIK3CD. We found that L666P promoted the cell proliferation and migration of human umbilical vein endothelial cells (HUVECs) and induced hyperactivation of the mTOR pathway. These findings indicate that the PIK3CD mutation affects downstream signalling in endothelial cells, which may impair normal lymphangiogenesis.

Conclusions

This study reveals a novel candidate gene associated with the development of LMs, which is consistent with previous researches. These findings in our study may offer a novel gene target for developing therapies, which acts in tight interaction with the previously known PIK3CA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01782-9.

Recent Progress in Lymphangioma

Lymphangioma is a common type of congenital vascular disease in children with a broad spectrum of clinical manifestations. The current classification of lymphangioma by International Society for the Study of Vascular Anomalies is largely based on the clinical manifestations and complications and is not sufficient for selection of therapeutic strategies and prognosis prediction. The clinical management and outcome of lymphangioma largely depend on the clinical classification and the location of the disease, ranging from spontaneous regression with no treatment to severe sequelae even with comprehensive treatment. Recently, rapid progression has been made toward elucidating the molecular pathology of lymphangioma and the development of treatments. Several signaling pathways have been revealed to be involved in the progression and development of lymphangioma, and specific inhibitors targeting these pathways have been investigated for clinical applications and clinical trials. Some drugs already currently in clinical use for other diseases were found to be effective for lymphangioma, although the mechanisms underlying the anti-tumor effects remain unclear. Molecular classification based on molecular pathology and investigation of the molecular mechanisms of current clinical drugs is the next step toward developing more effective individualized treatment of children with lymphangioma with reduced side effects.