title: Therapeutic targeting of melanoma cells using neural stem cells expressing carboxylesterase, a CPT-11 activating enzyme.
abstract: Neural stem cells (NSCs) have been investigated in preclinical models as delivery vehicles for therapeutic genes for treatment of tumors in the central nervous system and other organs. Melanoma at early stages is effectively treated with surgery and radiotherapy, however metastatic disease is almost universally fatal, thus novel therapeutic approaches are needed. We studied the use of HB1.F3.CD therapeutic NSCs, a well-characterized clonal cell line derived from human fetal telencephalon, for their potential of secreting prodrug-activating enzyme. HB1.F3.CD cells were transduced by adenovirus encoding rabbit carboxylesterase (rCE), which converts CPT-11 into SN-38, a potent topoisomerase 1 inhibitor. In vitro cell migration assays revealed robust migration of NSCs to conditioned media from melanoma cells. Cytokine profiles showed that IL-6, IL-8, MCP-1 and TIMP-2, known chemoattractants for stem cells, were highly expressed by melanoma cells. Exposure of melanoma cells to conditioned media from the HB1.F3.CD.rCE cells in the presence of CPT-11 increased the tumor cell-killing effect by approximately 100-fold when compared to CPT-11 alone. Our data demonstrate the rational for NSC-based enzyme/prodrug therapeutic approach to target metastatic melanoma. Future experiments will evaluate the therapeutic efficacy of NSC-mediated melanoma therapy in animal models, which will provide the basis for targeted therapy in patients with advanced melanoma.
authors: Division of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA 91010-3000, USA. mgutova@coh.org
authors: Margarita
authors: M
authors: Gutova
authors: Joseph
authors: J
authors: Najbauer
authors: Mike Y
authors: MY
authors: Chen
authors: Philip M
authors: PM
authors: Potter
authors: Seung U
authors: SU
authors: Kim
authors: Karen S
authors: KS
authors: Aboody
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000378:metabolism / Q000627:therapeutic use; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000627:therapeutic use; D043182:Carboxylesterase / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D016207:Cytokines / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000627:therapeutic use; D006801:Humans; D000077146:Irinotecan; D008545:Melanoma / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D009474:Neurons / Q000166:cytology / Q000201:enzymology* / Q000502:physiology*; D011817:Rabbits; D013234:Stem Cells / Q000166:cytology / Q000201:enzymology* / Q000502:physiology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D016207:Cytokines; D004791:Enzyme Inhibitors; D000077146:Irinotecan; D043182:Carboxylesterase; D002166:Camptothecin