A cell-penetrating ARF peptide inhibitor of FoxM1 in mouse hepatocellular carcinoma treatment
Galina A. Gusarova, … , Vladimir Petrovic, Robert H. Costa
Galina A. Gusarova, … , Vladimir Petrovic, Robert H. Costa
Published January 2, 2007
Citation Information: J Clin Invest. 2007;117(1):99-111. https://doi.org/10.1172/JCI27527.
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Research Article

A cell-penetrating ARF peptide inhibitor of FoxM1 in mouse hepatocellular carcinoma treatment

Abstract

The forkhead box m1 (Foxm1) transcription factor is essential for initiation of carcinogen-induced liver tumors; however, whether FoxM1 constitutes a therapeutic target for liver cancer treatment remains unknown. In this study, we used diethylnitrosamine/phenobarbital treatment to induce hepatocellular carcinomas (HCCs) in either WT mice or Arf–/–Rosa26-FoxM1b Tg mice, in which forkhead box M1b (FoxM1b) is overexpressed and alternative reading frame (ARF) inhibition of FoxM1 transcriptional activity is eliminated. To pharmacologically reduce FoxM1 activity in HCCs, we subjected these HCC-bearing mice to daily injections of a cell-penetrating ARF26–44 peptide inhibitor of FoxM1 function. After 4 weeks of this treatment, HCC regions displayed reduced tumor cell proliferation and angiogenesis and a significant increase in apoptosis within the HCC region but not in the adjacent normal liver tissue. ARF peptide treatment also induced apoptosis of several distinct human hepatoma cell lines, which correlated with reduced protein levels of the mitotic regulatory genes encoding polo-like kinase 1, aurora B kinase, and survivin, all of which are transcriptional targets of FoxM1 that are highly expressed in cancer cells and function to prevent apoptosis. These studies indicate that ARF peptide treatment is an effective therapeutic approach to limit proliferation and induce apoptosis of liver cancer cells in vivo.

Authors

Galina A. Gusarova, I-Ching Wang, Michael L. Major, Vladimir V. Kalinichenko, Timothy Ackerson, Vladimir Petrovic, Robert H. Costa

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Figure 5

H&E-stained liver tumors from mice treated with WT ARF26–44 peptide.

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H&E-stained liver tumors from mice treated with WT ARF26–44 peptide....
Hepatic tumors were induced in Foxm1fl/fl mice with DEN/PB treatment, and then they were treated with daily i.p. injections of 5 mg/kg body weight of WT ARF26–44 peptide or mutant ARF37–44 peptide for 4 or 8 weeks (see Figure 2A legend). Arrows indicate red-staining cells undergoing apoptosis, and arrowheads show liver tumor margins. (A–F) H&E-stained liver tumor sections from WT ARF26–44 peptide–treated mice revealed that many of the hepatic adenomas and HCC tumor cells stained red and were rounded up, which is indicative of apoptosis. E and F are higher-magnification images of C and D. No red-staining apoptotic cells were found in either the surrounding, normal liver tissue or in liver tumors from dsRNA CKO Mx-Cre Foxm1–/– mice (see Figure 1, E–G). (G–L) No red-staining tumor cells were found in H&E-stained liver tumor sections from mice treated with either PBS or mutant ARF37–44 peptide. Magnification, ×200 (A–D and G–L); ×400 (E and F).