1p13.2 deletion displays clinical features overlapping Noonan syndrome, likely related to NRAS gene haploinsufficiency
GENETICS AND MOLECULAR BIOLOGY
Authors: Linhares, Natalia Duarte; Menezes Freire, Maira Cristina; do Carmo Lisboa Cardenas, Raony Guimaraes Correa; Pena, Heloisa Barbosa; Lachlan, Katherine; Dallapiccola, Bruno; Bacino, Carlos; Delobel, Bruno; James, Paul; Thuresson, Ann-Charlotte; Anneren, Goran; Pena, Sergio D. J.
Abstract
Deletion-induced hemizygosity may unmask deleterious autosomal recessive variants and be a cause of the phenotypic variability observed in microdeletion syndromes. We performed complete exome sequencing (WES) analysis to examine this possibility in a patient with 1p13.2 microdeletion. Since the patient displayed clinical features suggestive of Noonan Syndrome (NS), we also used WES to rule out the presence of pathogenic variants in any of the genes associated with the different types of NS. We concluded that the clinical findings could be attributed solely to the 1p13.2 haploinsufficiency. Retrospective analysis of other nine reported patients with 1p13.2 microdeletions showed that six of them also presented some characteristics of NS. In all these cases, the deleted segment included the NRAS gene. Gain-of-function mutations of NRAS gene are causally related to NS type 6. Thus, it is conceivable that NRAS haploinsufficiency and gain-of-function mutations may have similar clinical consequences. The same phenomenon has been described for two other genes belonging to the Ras/MAPK pathway: MAP2K2 and SHOC2. In conclusion, we here report genotype-phenotype correlations in patients with chromosome 1p13.2 microdeletions and we propose that NRAS may be a critical gene for the NS characteristics in the patients.
A new abietane diterpenoid from Ajuga ovalifolia var. calantha induces human lung epithelial A549 cell apoptosis by inhibiting SHP2
FITOTERAPIA
Authors: Liu, De-ming; Cao, Zhi-Xing; Yan, Hong-ling; Li, Wen; Yang, Fan; Zhao, Wen-Ji; Diao, Qing-chun; Tan, Yu-zhu
Abstract
The Src-homology 2 domain-containing phosphatase 2 (SHP2), encoded by PTPN11, has been reported oncogenic tyrosine phosphatase associated with various tumors and played critical roles in many cell signaling events. Targeting SHP2 by small molecules may be a promising way for cancer therapy. Herein, a new abietane diterpenoid, named 3-acetoxylteuvincenone G (3-AG), was isolated from the whole plants of Ajuga ovalifolia var. calantha. The structure of the new compound was elucidated by means of extensive spectroscopic analyses. Using recombinant enzyme activity assay and cellular thermal shift assay, we found that 3-AG was a selective inhibitor of SHP2. Molecular docking suggested 3-AG displayed an orientation favorable to nucleophilic attack in the catalytic domain of SHP2. 3-AG suppressed A549 cell proliferation (IC50 = 10.79 +/- 0.14 mu M), invasion and induced cell apoptosis through SHP2/ERK1/2 and SHP2/AKT pathways. In summary, 3-AG, a potent, selective, and efficacious SHP2 inhibitor, may be a promising small molecule to treat human lung epithelial cancer.