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Pheochromocytoma cell lines from heterozygous neurofibromatosis knockout mice
J F Powers1, M J Evinger, P Tsokas
1Department of Pathology, Box 802, New England Medical Center and Tufts University School of Medicine, 750 Washington Street, Boston, MA 02111, USA. jpowersl@lifespan.org
Abstract:
Transplantable tumors and cell lines have been developed from pheochromocytomas arising in mice with a heterozygous knockout mutation of the neurofibromatosis gene, Nf1. Nf1 encodes a ras-GTPase-activating protein, neurofibromin, and mouse pheochromocytoma (MPC) cells in primary cultures typically show extensive spontaneous neuronal differentiation that may result from the loss of the remaining wild-type allele and defective regulation of ras signaling. However, all MPC cell lines express neurofibromin, suggesting that preservation of the wild-type allele may be required to permit the propagation of MPC cells in vitro. MPC lines differ from PC12 cells in that they express both endogenous phenylethanolamine N-methyltransferase (PNMT) and full-length PNMT reporter constructs. PNMT expression is increased by dexamethasone and by cell-cell contact in suspension cultures. Mouse pheochromocytomas are a new tool for studying genes and signaling pathways that regulate cell growth and differentiation in adrenal medullary neoplasms and are a unique model for studying the regulation of PNMT expression.
Insights
New mouse models of neurofibromatosis type 1 (NF1) pheochromocytomas offer insights into tumor growth and neuronal differentiation. These models help study ras signaling and phenylethanolamine N-methyltransferase (PNMT) regulation in adrenal neoplasms.
Area of Science:
- Oncology
- Neuroscience
- Genetics
Background:
- Neurofibromatosis type 1 (NF1) is a genetic disorder associated with increased cancer risk, including pheochromocytomas.
- NF1 gene encodes neurofibromin, a tumor suppressor protein regulating ras signaling.
- Mouse models are crucial for understanding complex signaling pathways in cancer development.
Purpose of the Study:
- To develop and characterize transplantable tumors and cell lines from NF1-associated pheochromocytomas in mice.
- To investigate the role of neurofibromin and ras signaling in pheochromocytoma development and differentiation.
- To explore the regulation of phenylethanolamine N-methyltransferase (PNMT) in adrenal medullary neoplasms.
Main Methods:
- Development of transplantable tumors and cell lines from heterozygous Nf1 knockout mice.
- Analysis of neurofibromin expression and ras signaling in mouse pheochromocytoma (MPC) cells.
- Assessment of spontaneous neuronal differentiation in MPC cell cultures.
- Investigation of PNMT expression regulation by dexamethasone and cell-cell contact.
Main Results:
- MPC cell lines were successfully established and exhibit characteristics of pheochromocytomas.
- MPC cells show spontaneous neuronal differentiation, potentially linked to defective ras signaling.
- All MPC lines express neurofibromin, suggesting its role in in vitro propagation.
- MPC lines express endogenous PNMT, unlike some other models, and PNMT expression is modulated by dexamethasone and cell contact.
Conclusions:
- Mouse pheochromocytomas provide a novel tool for studying NF1-related tumors and adrenal medullary neoplasia.
- These models facilitate research into genes and signaling pathways controlling tumor growth and differentiation.
- The models offer a unique system for investigating PNMT expression regulation in the adrenal medulla.