Abstract
Colorectal carcinomas (CRC) harbor well-defined genetic abnormalities, including aberrant activation of β-catenin (β-cat) and KRAS, but independent targeting of these molecules seems to have limited therapeutic effect. In this study, we report therapeutic effects of combined targeting of different oncogenes in CRC. Inducible short hairpin RNA (shRNA)-mediated silencing of β-cat, ITF2, or KRAS decreased proliferation by 88%, 72%, and 45%, respectively, with no significant apoptosis in any case. In contrast, combined blockade of β-cat and ITF2 inhibited proliferation by 99% with massive apoptosis. Similar effects occurred after combined shRNA against β-cat and KRAS. In vivo, single oncogene blockade inhibited the growth of established tumors by up to 30%, whereas dual β-cat and ITF2 targeting caused 93% inhibition. Similar tumor growth suppression was achieved by double β-cat/KRAS shRNA in vivo. Our findings illustrate an effective therapeutic principle in CRC based on a combination targeting strategy that includes the ITF2 oncogene, which represents a novel therapeutic target.
©2010 AACR.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Apoptosis / genetics
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / antagonists & inhibitors*
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism
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Colorectal Neoplasms / genetics
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Colorectal Neoplasms / metabolism
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Colorectal Neoplasms / pathology
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Colorectal Neoplasms / therapy*
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Down-Regulation
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Doxycycline / pharmacology
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Female
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Gene Expression Regulation, Neoplastic
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HCT116 Cells
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Humans
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Mice
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Mice, Nude
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Proto-Oncogene Proteins / antagonists & inhibitors*
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins p21(ras)
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RNA, Small Interfering / genetics
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Signal Transduction
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Transcription Factor 4
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Transcription Factors / antagonists & inhibitors*
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Transfection
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Xenograft Model Antitumor Assays
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beta Catenin / antagonists & inhibitors*
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beta Catenin / genetics
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beta Catenin / metabolism
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ras Proteins / antagonists & inhibitors*
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ras Proteins / genetics
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ras Proteins / metabolism
Substances
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
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CTNNB1 protein, mouse
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KRAS protein, human
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Proto-Oncogene Proteins
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RNA, Small Interfering
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TCF4 protein, human
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Transcription Factor 4
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Transcription Factors
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beta Catenin
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Proto-Oncogene Proteins p21(ras)
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ras Proteins
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Doxycycline