A fragment of the HMGN2 protein homes to the nuclei of tumor cells and tumor endothelial cells in vivo.
We used a screening procedure to identify protein domains from phage-displayed cDNA libraries that bind both to bone marrow endothelial progenitor cells and tumor vasculature. Screening phage for binding of progenitor cell-enriched bone marrow cells in vitro, and for homing to HL-60 human leukemia cell xenograft tumors in vivo, yielded a cDNA fragment that encodes an N-terminal fragment of human high mobility group protein 2 (HMGN2, formerly HMG-17). Upon i.v. injection, phage displaying this HMGN2 fragment homed to HL-60 and MDA-MB-435 tumors. Testing of subfragments localized the full binding activity to a 31-aa peptide (F3) in the HMGN2 sequence. Fluorescein-labeled F3 peptide bound to and was internalized by HL-60 cells and human MDA-MB-435 breast cancer cells, appearing initially in the cytoplasm and then in the nuclei of these cells. Fluorescent F3 accumulated in HL-60 and MDA-MB-435 tumors after an i.v. injection, appearing in the nuclei of tumor endothelial cells and tumor cells. Thus, F3 can carry a payload (phage, fluorescein) to a tumor and into the cell nuclei in the tumor. This peptide may be suitable for targeting cytotoxic drugs and gene therapy vectors into tumors.
Porkka
Kimmo
K
Cancer Research Center, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
Laakkonen
Pirjo
P
Hoffman
Jason A
JA
Bernasconi
Michele
M
Ruoslahti
Erkki
E
D000818:Animals; D001854:Bone Marrow Cells / Q000502:physiology; D001943:Breast Neoplasms; D002467:Cell Nucleus / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism*; D005260:Female; D015723:Gene Library; D018922:HL-60 Cells; D024242:HMGN2 Protein / Q000737:chemistry / Q000378:metabolism*; D006412:Hematopoietic Stem Cells / Q000502:physiology; D006801:Humans; D051379:Mice; D010446:Peptide Fragments / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured
D024242:HMGN2 Protein; D010446:Peptide Fragments; D020033:Protein Isoforms; D012333:RNA, Messenger; D011994:Recombinant Proteins