modeling-osteosarcoma-using-li-fraumeni-syndrome-patient-derived

Modeling Osteosarcoma Using Li-Fraumeni Syndrome Patient-derived Induced Pluripotent Stem Cells

Li-Fraumeni syndrome (LFS) is an autosomal dominant hereditary cancer disorder. Patients with LFS are predisposed to a various type of tumors, including ...

The University of Texas Health Science Center at Houston

MAX dimerization protein 1 (MAD1) is a transcription suppressor that antagonizes MYC-mediated transcription activation, and the inhibition mechanism occurs mainly through the competition of target genes' promoter MYC binding sites by MAD1. The promoter binding proteins switch between MYC and MAD1 affects cell proliferation and differentiation. However, little is known about MAD1's regulation process in cancer cells. Here, we present evidence that AKT inhibits MAD1-mediated transcription repression by physical interaction with and phosphorylation of MAD1. Phosphorylation reduces the binding affinity between MAD1 and its target genes' promoter and thereby abolishes its transcription suppression function. Mutation of the phosphorylation site from serine to alanine rescues the DNA-binding ability in the presence of activated AKT. In addition, AKT inhibits MAD1-mediated target genes (hTERT and ODC) transcription repression and promotes cell cycle and cell growth. However, mutated S145A MAD1 abrogates the inhibition by AKT. Thus, our results suggest that phosphorylation of MAD1 by AKT inhibits MAD1-mediated transcription suppression and subsequently activates the transcription of MAD1 target genes.

The suppression of MAD1 by AKT-mediated phosphorylation activates MAD1 target genes transcription.

The Retinoblastoma 1 (RB1) tumor suppressor, a member of the Retinoblastoma gene family, functions as a pocket protein for the functional binding of E2F transcription factors. About 1/3 of retinoblastoma patients harbor a germline RB1 mutation or deletion, leading to the development of retinoblastoma. Here, we demonstrate generation of a heterozygous deletion of the RB1 gene in the H1 human embryonic stem cell line using CRISPR/Cas9 nickase genome editing. The RB1 heterozygous knockout H1 cell line shows a normal karyotype, maintains a pluripotent state, and is capable of differentiation to the three germline layers.

Generation of human embryonic stem cell line with heterozygous RB1 deletion by CRIPSR/Cas9 nickase.

The tumor suppressor gene TP53 is the most frequently mutated gene in human cancers. Many hot-spot mutations of TP53 confer novel functions not found in wild-type p53 and contribute to tumor development and progression. We report on the generation of a H1 human embryonic stem cell line carrying a homozygous TP53 R282W mutation using TALEN-mediated genome editing. The generated cell line demonstrates normal karyotype, maintains a pluripotent state, and is capable of generating a teratoma in vivo containing tissues from all three germ layers.

A homozygous p53 R282W mutant human embryonic stem cell line generated using TALEN-mediated precise gene editing.

Genetic mutations in TP53 contribute to multiple human cancers. Here we report the generation of a H1-p53(R248W/R248W) human embryonic stem cell line harboring a homozygous TP53 R248W mutation created by TALEN-mediated precise gene editing. The H1-p53(R248W/R248W) cell line maintains a normal karyotype, robust pluripotency gene expression, and the potential to differentiate to the three germ layers.

Article	Year
The suppression of MAD1 by AKT-mediated phosphorylation activates MAD1 target genes transcription. Molecular carcinogenesis\| PubMed ID: 19526459	2009
Generation of human embryonic stem cell line with heterozygous RB1 deletion by CRIPSR/Cas9 nickase. Stem cell research\| PubMed ID: 29414415	2018
A homozygous p53 R282W mutant human embryonic stem cell line generated using TALEN-mediated precise gene editing. Stem cell research\| PubMed ID: 29414603	2018
Establishment of a human embryonic stem cell line with homozygous TP53 R248W mutant by TALEN mediated gene editing. Stem cell research\| PubMed ID: 29730572	2018

Mo Liu

Biography

JoVE Journal Publications

Other Publications