Human U251MG glioma cells expressing the membrane form of macrophage colony-stimulating factor (mM-CSF) are killed by human monocytes in vitro and are rejected within immunodeficient mice via paraptosis that is associated with increased expression of three different heat shock proteins.
Human U251MG glioma cells retrovirally transduced with the human gene for the membrane form of macrophage colony-stimulating factor (mM-CSF) were investigated. The clones, MG-2F11 and MG-2C4, that expressed the most mM-CSF, but not the viral vector or the parental U251MG cells, were killed by both murine and human monocyte/macrophages in cytotoxicity assays. MG-2F11 cells failed to form subcutaneous tumors in either nude or NIH-bg-nu-xidBR mice, while mice inoculated with the U251MG viral vector (MG-VV) cells developed tumors. Electron microscopy studies showed that 4 hours after subcutaneous injection, the mM-CSF-transduced cells began dying of a process that resembled paraptosis. The dying tumor cells were swollen and had extensive vacuolization of their mitochondria and endoplasm reticulum. This killing process was complete within 24 hours. Macrophage-like cells were immediately adjacent to the killed MG-2F11 cells. Immunohistological staining for the heat shock proteins HSP60, HSP70 and GRP94 (gp96) showed that 18 hours after inoculation into nude mice, the MG-2F11 injection site was two to four times more intensely stained than the MG-VV cells. This study shows that human gliomas transduced with mM-CSF have the potential to be used as a safe live tumor cell vaccine.
Department of Diagnostic and Molecular Medicine, Box 151 Veterans Affairs Medical Center, 5901 E 7th Street, Long Beach, California 90822, USA. martin.jadus@med.va.gov
Martin R
MR
Jadus
Yijun
Y
Chen
Mehrdokht Tarbiyat
MT
Boldaji
Christina
C
Delgado
Ramon
R
Sanchez
Thomas
T
Douglass
Usama
U
Al-Atar
William
W
Schulz
Cheri
C
Lloyd
H Terry
HT
Wepsic
D000818:Animals; D017209:Apoptosis; D018834:Chaperonin 60 / Q000378:metabolism*; D003602:Cytotoxicity, Immunologic; D004721:Endoplasmic Reticulum / Q000378:metabolism; D015870:Gene Expression / Q000502:physiology; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D016173:Macrophage Colony-Stimulating Factor / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008566:Membranes; D051379:Mice; D008817:Mice, Mutant Strains; D008819:Mice, Nude; D008928:Mitochondria / Q000378:metabolism; D009000:Monocytes / Q000502:physiology*; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured; D014617:Vacuoles / Q000378:metabolism
D018834:Chaperonin 60; D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; C018551:glucose-regulated proteins; D016173:Macrophage Colony-Stimulating Factor