Dissecting the Biology and Therapeutic Vulnerabilities of RB1-Mutant Osteosarcoma Using RB iPSCs
Abstract
The RB1 tumor suppressor has been widely recognized for its role in inhibiting tumor initiation, development, and progression. RB1 functions in negatively regulating cell cycle progression by interacting with E2F1/2/3 transcription factors. In addition to negatively regulating G1/S transition in the cell cycle, it remains incompletely defined if RB1 also contributes to other stages of the cell cycle such as G2/M. RB1 missense mutations and deletions are found in more than 30 percent of clinical osteosarcoma specimens, highlighting the crucial role of RB1 in preventing bone malignancy. Patients with hereditary retinoblastoma (RB), an inherited autosomal dominant cancer disorder caused by germline mutations/deletions in the RB1 tumor suppressor gene, have a greater than 400-fold increased incidence of osteosarcoma, suggesting a strong mechanistic link between RB1 loss and osteosarcomagenesis. Although mice offer many advantages when conducting cancer research, unlike humans Rb1 knockout mice do not develop OS, suggesting the urgent requirement for alternative disease models to understand how RB1 mutation leads to osteosarcomagenesis. Our experience in iPSC technology enables us to perfect a model system for RB-associated bone malignancies and explore therapeutic interventions. We have reprogrammed RB patients fibroblasts to iPSCs. We also applied CRISPR/Cas9 to correct RB1 mutation in RB iPSCs, named as cRB iPSCs, and use these cells as isogenic controls. Since OBs are derived from multi-potent mesenchymal stem cells (MSCs), we first differentiated WT, RB, and cRB iPSCs to their corresponding MSCs (CD105+/CD166+/CD24-) and then to OBs by our defined MSC and OB lineage differentiation methods. Performing in vivo xenografts, we found potential tumorigenic ability in RB OBs but not WT and cRB OBs.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2022
- Accession Number
- AD1214492
Entities
People
- Dandan Zhu
Organizations
- University of Texas Health Science Center at Houston