Unbiased selection of bone marrow derived cells as carriers for cancer gene therapy.
BACKGROUND
There is currently great interest in development of cell-based carriers for delivery of viral vectors to metastatic tumors. To date, several cell carriers have been tested based largely upon their predicted tumor-localizing properties. However, cell types may exist which can be mobilized from the circulation by a tumor which have not yet been identified. Here we use an unbiased screen of bone marrow (BM) cells to identify cells which localize to tumors and which might serve as effective candidate cell carriers without any prior prediction or selection.


METHODS
Unsorted BM cells from green fluorescent protein (GFP)-transgenic donor mice were adoptively transferred into C57Bl/6 mice bearing pre-established subcutaneous B16 melanoma tumors. Forty-eight hours and eight days later, tumors, organs and blood were analyzed for GFP-expressing cells by flow cytometry. The phenotype of GFP cells in organs was determined by co-staining with specific cell surface markers.


RESULTS
CD45(+) hematopoietic cells were readily detected in tumor, spleen, bone marrow, blood and lung at both time points. Within these CD45(+) cell populations, preferential accumulation in the tumor was observed of cells expressing Sca-1, c-kit, NK1.1, Thy1.2, CD14, Mac-3 and/or CD11c. Lymphodepletion increased homing to spleen and bone marrow, but not to tumors.


CONCLUSIONS
We have used an in vivo screen to identify populations of BM-derived donor cells which accumulate within tumors. These studies will direct rational selection of specific cell types which can be tested in standardized assays of cell carrier efficiency for the treatment of metastatic tumors.
Lang
Susanne I
SI
Molecular Medicine Program, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA.
Kottke
Timothy
T
Thompson
Jill
J
Vile
Richard G
RG
D019264:Adoptive Transfer / Q000379:methods*; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism; D002465:Cell Movement; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D049452:Green Fluorescent Proteins; D016130:Immunophenotyping; D008546:Melanoma, Experimental / Q000628:therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009362:Neoplasm Metastasis / Q000188:drug therapy*; D009369:Neoplasms / Q000473:pathology / Q000628:therapy; D014018:Tissue Distribution
D049452:Green Fluorescent Proteins