Analysis of Induced Pluripotent Stem Cells from a BRCA1 Mutant Family

Abstract

SummaryUnderstanding BRCA1 mutant cancers is hampered by difficulties in obtaining primary cells from patients. We therefore generated and characterized 24 induced pluripotent stem cell (iPSC) lines from fibroblasts of eight individuals from a BRCA1 5382insC mutant family. All BRCA1 5382insC heterozygous fibroblasts, iPSCs, and teratomas maintained equivalent expression of both wild-type and mutant BRCA1 transcripts. Although no difference in differentiation capacity was observed between BRCA1 wild-type and mutant iPSCs, there was elevated protein kinase C-theta (PKC-theta) in BRCA1 mutant iPSCs. Cancer cell lines with BRCA1 mutations and hormone-receptor-negative breast cancers also displayed elevated PKC-theta. Genome sequencing of the 24 iPSC lines showed a similar frequency of reprogramming-associated de novo mutations in BRCA1 mutant and wild-type iPSCs. These data indicate that iPSC lines can be derived from BRCA1 mutant fibroblasts to study the effects of the mutation on gene expression and genome stability.

Distinct Brca1 Mutations Differentially Reduce Hematopoietic Stem Cell Function

“…These C-terminal mutations frequently lead to cancer phenotypes distinct from those caused by mutations elsewhere in the gene (Rebbeck et al, 2015). We have found that the common Ashkenazi Jewish BRCA1 5382insC founder mutation results in expression of a mutant transcript in the same amounts as BRCA1 wild-type message in fibroblasts, induced pluripotent stem cells and teratomas (Soyombo et al, 2013). The 5382insC mutation leads to a C-terminal frame-shift mutation.…”

“…We and others have found that frameshift or stop-gain mutations in the last few exons of the BRCA1 gene encode non-functional mutant proteins (Scully et al, 1999) expressed from messages that do not experience RNA decay (Perrin-Vidoz et al, 2002; Soyombo et al, 2013). These C-terminal mutations frequently lead to cancer phenotypes distinct from those caused by mutations elsewhere in the gene (Rebbeck et al, 2015).…”

“…Expression of the BRCA1 5382insC mutant mRNA from humans heterozygous for the BRCA1 5382insC mutation is equivalent to the expression of the wild type mRNA from the other allele in primary human fibroblasts, induced pluripotent stem cells and teratomas. However, the expression of BRCA1 5382insC in these cells does not promote excessive cell death, differentiation, survival or growth (Soyombo et al, 2013). Further, heterologous expression of this mutant BRCA1 in cell lines does not lead to altered growth or survival ( data not shown ).…”

Patient-derived induced pluripotent stem cells in cancer research and precision oncology

“…Incompletely reprogrammed ‘iPSC-like’ cells—cells that have not attained independence from exogenous expression of reprogramming TFs—have been generated from patients with pancreatic adenocarcinoma 33 . iPSCs have also been generated from patients with familial cancer predisposition syndromes resulting from germline mutations: Li–Fraumeni syndrome ( TP53 mutation) 34 , Fanconi anemia ( FANCA and FANCC mutations) 35 , familial platelet disorder (FPD) with a predisposition to acute myeloid leukemia (AML) (FPD/AML; RUNX1 mutation) 36 and breast cancer predisposition ( BRCA1 mutation) 37 . Li–Fraumeni syndrome iPSCs showed defective osteoblastic differentiation and tumorigenic potential, and they captured gene signatures of primary osteosarcomas, a tumor type that commonly develops in these patients 34 .…”

hiPSC‐derived iMSCs: NextGen MSCs as an advanced therapeutically active cell resource for regenerative medicine

“…Facioscapulohumeral muscular dystrophy (FSHD) [184] Limb-girdle muscular dystrophy (LGMD) [185] Myotonic dystrophy type 1 (MyD1) [186] Marfan syndrome (MFS) [187] Fibrodysplsia ossificans progressiva (FOP) [188] Lung disorder Cystic fibrosis (CF) [189] Pulmonary alveolar proteinosis (PAP) [190] Emphysema (EP) [191] Dermatological Disorder Recessive dystrophic epidermolysis bullosa (RDEB) [192,193] Scleroderma (SC) [191] Focal dermal hypoplasia (FDH) [194] Hermansky-Pudlak syndrome (HPS) [195] Chediak-Higashi syndrome (CHS) [195] Cancer Breast cancer (BC) [196] Opthalmological disorder Retinitis pigmentosa (RP) [53,197,198] Gyrate atrophy (GA) [199] Best disease (BD) [200] Cataract (Cat) [201] Ectrodactyly-ectodermal dysplasia-cleft syndrome (EEC) [202] Nephrology End stage renal disease (ESRD) [203] Aneuploidy Turner syndrome (TS) [204] Warkany syndrome (WKS) [204] Patau syndrome (PS) [204] Emanuel syndrome (ES) [204] Klinefelter's syndrome (KS) [205] Down's syndrome [125] 1580 States, the human iPSC products are regulated by Centre for Biologics Evaluation and Research at the United States Food and Drug Administration (USFDA) [214]. Before proceeding with the clinical trials, the iPSC-derived products are subjected to preclinical testing that requires extensive examination of safety, feasibility and efficacy [215].…”