Alami N, Page V, Yu Q, Jerome L, Paterson J, Shiry L, Leyland-Jones B. Recombinant human insulin-like growth factor-binding protein 3 inhibits tumor growth and targets the Akt pathway in lung and colon cancer models.
Growth Horm IGF Res 2008;
18:487-496. [PMID:
18502161 DOI:
10.1016/j.ghir.2008.04.002]
[Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Revised: 04/04/2008] [Accepted: 04/09/2008] [Indexed: 01/13/2023]
Abstract
OBJECTIVE
Insulin-like growth factor-binding protein 3 (IGFBP-3) can induce antiproliferative and proapoptotic effects in human cancer cells, by IGF-I independent mechanisms. The antitumor efficacy of recombinant human IGFBP-3 (rhIGFBP-3) and its interaction with chemotherapy in lung and colon cancers, in vitro and in vivo was evaluated. The effects of the different treatments on IGF-IR signaling pathways were also examined.
DESIGN
Antiproliferative in vitro assay using rhIGFBP-3, as single agent or in combination with carboplatin or irinotecan against the murine Lewis Lung (M-3LL) and LoVo cell lines, respectively was performed. In the M-3LL model in vivo model, mice were treated with rhIGFBP-3 (3 or 10 mg/kg), carboplatin (25 or 50 mg/kg) alone or in combined treatments. In the LoVo xenograft model, mice were treated with rhIGFBP-3 (3, 10 or 30 mg/kg), irinotecan (10 or 20 mg/kg), as monotherapies or in combinations.
RESULTS
rhIGFBP-3 elicited a dose-dependent tumor growth inhibition on the M-3LL model and produced a significant tumor growth inhibition at the highest dose tested. However, it failed to improve the antitumor response to carboplatin. In the LoVo colorectal xenograft model, rhIGFBP-3 caused significant single-agent inhibitory effect and enhanced the antitumor activity of irinotecan at their lowest doses tested. Western blot analysis suggests that the observed tumor growth inhibition by rhIGFBP-3 correlates with decreased Akt phosphorylation in both M-3LL and LoVo cell lines in vitro.
CONCLUSIONS
Our novel findings provide evidence for in vivo activity of rhIGFBP-3 against lung and colon tumor models and reveal new insight into its interaction with chemotherapeutic drugs. The antitumor effects of rhIGFBP-3 are associated with a downregulation of AKT signaling.
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