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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2009-5-18
pubmed:abstractText
The insulin-like growth factor receptor is overexpressed on many types of cancer cells and has been implicated in metastasis and resistance to apoptosis. We report here the development of a novel covalent conjugate that contains the antifolate drug methotrexate coupled to an engineered variant of insulin-like growth factor-1 (IGF-1), long-R3-IGF-1, which was designed to target methotrexate to tumor cells that overexpress the membrane IGF-1 receptor. The IGF-methotrexate conjugate was found to contain at least 4 methotrexate molecules per IGF-1 protein. The IGF-methotrexate conjugate bound to MCF7 breast cancer cells with greater than 3.3-fold higher affinity than unconjugated long-R3-IGF-1 in a competition binding assay against radiolabeled wild-type IGF-1. Compared with free methotrexate, the IGF-methotrexate conjugate required slightly higher concentrations to inhibit the in vitro growth of the human prostate cancer cell line LNCaP. In vivo, however, in a mouse xenograft model using LNCaP cells, the IGF-methotrexate conjugate was more effective than free methotrexate even at a 6.25-fold lower molar dosage. Similarly, MCF7 xenografts were inhibited more effectively by the IGF-methotrexate conjugate than free methotrexate, even at a 4-fold lower molar dosage. Our results suggest that the targeting of the IGF receptor on tumor cells and tumor-related tissues with IGF-chemotherapy conjugates may substantially increase the specific drug localization and therapeutic effect in the tumor.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1931-5244
pubmed:author
pubmed:issnType
Print
pubmed:volume
153
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
275-82
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Novel insulin-like growth factor-methotrexate covalent conjugate inhibits tumor growth in vivo at lower dosage than methotrexate alone.
pubmed:affiliation
IGF Oncology, LLC, Saint Paul, MN 55110, USA. hmctavish@IGFOncology.com
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't