HER-2-targeted antisense oligonucleotide results in sensitization of head and neck cancer cells to chemotherapeutic agents.
Existing HER-2 targeted therapies for human head and neck cancers, usually administered in combination with chemotherapeutic drugs or irradiation, include monoclonal antibodies to HER-2, receptor tyrosine kinase inhibitors and HER-2 specific immunotoxins. Instead of targeting the existing protein, interference with HER-2 mRNA translation by antisense oligonucleotides may be a more efficient method to downregulate levels of HER-2 protein for combination therapy. To test this hypothesis we have used a phosphorothioate pentadecamer, complementary to the HER-2 mRNA initiation codon region (AS HER-2 ODN), to increase sensitivity to four chemotherapeutic agents in human head and neck cancer cell lines, all of which express low levels of the HER-2 protein. To improve delivery into tumor cells, the AS HER-2 ODN was complexed with our previously established folate-liposome delivery system. Cell survival assays and Western blot analysis data demonstrated that folate-liposome mediated AS HER-2 oligonucleotide treatment inhibited cell growth and HER-2 expression, and induced apoptosis in SCC-25CP cells. Moreover, there was a synergistic effect on the percent of apoptotic cells. Additionally, the combination of folate-liposome-AS HER-2 ODN and CDDP had a synergistic effect on the induction of apoptosis. Using confocal microscopy, FITC labeled ODN (FITC-ODN) in complex with folate-liganded, rhodamine (Rh) labeled, cationic liposomes was observed to enter SCC-25CP head and neck tumor cells within 3 to 6 h. Intracellularly, the FITC-ODN separated from the Rh-folate-liposomes, and FITC-ODN accumulated in the nucleus while Rh-liposomes remained in punctate cytoplasmic structures. Thus, folate-liposome-mediated delivery of AS HER-2 ODN has potential as a new means of increasing the responsiveness of head and neck cancer to conventional chemotherapy.
Rait
Antonina S
AS
Lombardi Cancer Center, Georgetown University Medical Center, Washington, DC 20007, USA.
Pirollo
Kathleen F
KF
Ulick
David
D
Cullen
Kevin
K
Chang
Esther H
EH
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005822:Genetic Vectors; D006258:Head and Neck Neoplasms / Q000188:drug therapy*; D006801:Humans; D008081:Liposomes; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D012333:RNA, Messenger / Q000187:drug effects; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis / Q000187:drug effects* / Q000235:genetics; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D008081:Liposomes; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D018719:Erb-b2 Receptor Tyrosine Kinases