Abstract 3418: Additional mutation in PTPN11 gene promotes tumorigenesis of the NF1 gene mutated cells

• Published in: Cancer research (Chicago, Ill.) Vol. 77; no. 13_Supplement; p. 3418
• Main Authors: Arima, Yoshimi, Harigai, Ritsuko, Sato, Ryo, Takenouchi, Toshiki, Kosaki, Kenjiro, Saya, Hideyuki
• Format: Journal Article
• Language: English
• Published: 01.07.2017
• DOI: 10.1158/1538-7445.AM2017-3418
• ISSN: 0008-5472

The NF1 tumor suppressor gene encodes neurofibromin and is a functional Ras GTPase-activating protein (RasGAP) involved in negatively regulating the Ras signal by accelerating the conversion of activated Ras-GTP to inactive Ras-GDP. NF1 gene germline mutations cause Neurofibromatosis type 1 (NF1, von Recklinghausen disease). We hypothesized that additional genetic alterations promote the malignancy of NF1-associated tumors. To test our hypothesis, we inoculated a GFP-labeled human NF1-deficient cell line, sNF96.2-GFP, which has a frame-shift mutation (c.3683delC, p.Asn1229MetfsTer11) in the NF1 gene, into the renal sub-capsules of immunodeficient mice. A subclonal cell line, the A-1 cell, was established from the developed tumor. We found that A-1 cells show much higher tumorigenic activity and phosphorylation status of MEK and Akt than the parental sNF96.2-GFP cells. We analyzed the genomic DNA of both the sNF96.2 and the A-1 cells by using the next-generation sequencing and our medical exome panel of 4813 genes, which are known to be responsible for most human genetic disorders. We identified 18 heterozygous variants within coding regions of 17 genes that were present in the A-1 cells, but not in the original sNF96.2 cells. We found a single base substitution (c.1508G>T, p.Gly503Val) in the PTPN11 gene, which encodes the tyrosine phosphatese SHP-2, and is associated with the regulation of the Ras signaling pathway. It is critical to note that constitutional gain-of-function mutations in the PTPN11 gene cause Noonan Syndrome in humans due to activation of the Ras pathway. To determine the role of PTPN11 mutation in NF1-associated tumors, we established a cell line overexpressing PTPN11mut in sNF96.2-GFP cells. We inoculated parental cells and PTPN11mut cells into the subcutaneous of nude mice, and we found that PTPN11mut cells show much higher tumorigenic activity than the parental sNF96.2-GFP cells. Our data suggests that this additional gene mutation in PTPN11 promotes the malignant characteristics of NF1-associated tumors. Citation Format: Yoshimi Arima, Ritsuko Harigai, Ryo Sato, Toshiki Takenouchi, Kenjiro Kosaki, Hideyuki Saya. Additional mutation in PTPN11 gene promotes tumorigenesis of the NF1 gene mutated cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3418. doi:10.1158/1538-7445.AM2017-3418