Triple helix-forming oligodeoxyribonucleotides targeted to the human tumor necrosis factor (TNF) gene inhibit TNF production and block the TNF-dependent growth of human glioblastoma tumor cells

• Published in: Cancer research (Chicago, Ill.) Ill.), 1996-11, Vol.56 (22), p.5156-5164
• Main Authors: AGGARWAL, B. B, SCHWARZ, L, HOGAN, M. E, RONDO, R. F
• Format: Article
• Language: English
• Subjects: Animals; Antineoplastic agents; Base Sequence; Biological and medical sciences; Biological Assay; Cell Division - drug effects; Drug Design; General aspects; Glioblastoma - metabolism; Glioblastoma - pathology; Humans; Male; Medical sciences; Mice; Molecular Sequence Data; Oligodeoxyribonucleotides - chemistry; Oligodeoxyribonucleotides - metabolism; Oligodeoxyribonucleotides - pharmacology; Pharmacology. Drug treatments; Polymerase Chain Reaction; RNA, Messenger - metabolism; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha - biosynthesis; Tumor Necrosis Factor-alpha - genetics; Tumor Necrosis Factor-alpha - metabolism
• ISSN: 0008-5472; 1538-7445

Synthetic oligodeoxyribonucleotides (ODNs) designed to selectively inhibit the transcription or translation of specific genes are being used to modulate the activity of the targeted gene. Because multiple copies of mRNA can be transcribed from one actively expressed gene, ODNs that target double-stranded DNA and form triple helices upon binding with the gene itself have an advantage over ODNs that target the gene product (mRNA) in an antisense fashion. For the present studies, we designed four different triple helix-forming phosphodiester ODNs (TFOs) targeted to the tumor necrosis factor (TNF) gene and examined their effect on production of TNF and on cellular growth of tumors in which TNF acts as an autocrine growth factor. The ODNs J-109-50 and J-108-57 were designed to interact with polypurine oligonucleotides corresponding to the binding sites for nuclear factors kB (-237 to -208) and Sp1 (-58 to -33), respectively; J111-51 was designed to interact with a polypurine oligonucleotide in the third intron (+1429 to +1456) of the TNF gene. To enhance the cellular penetration and prevent degradation by cellular nucleases, the TFOs were modified at their 3' ends by either a cholesterol side chain or a propanolamine blocking group. Treatment of the human promonocytic cell line THP-1 with TNF-TFOs at a nontoxic concentration (2 microM) reduced the production of TNF. All of the TNF-TFOs tested were effective, and control-irrelevant TFOs were ineffective in inhibiting TNF production. The activity of the most efficacious TNF-TFOs also correlated with a decrease in TNF mRNA as observed by using reverse transcriptase PCR assays. In several tumors in which TNF acts as an autocrine growth factor, we examined the antiproliferative activity of J111-51. We found that in the human glioblastoma tumor cell line U-251, TNF-induced growth was blocked by J111-51 in a dose-dependent manner. Thus, overall results demonstrate that oligonucleotides directed to the specific regions of TNF can be designed, which may have a potential in cancer therapy.