Cell Signaling Technology

Product Pathways - Growth Factors/Cytokines

Human Insulin-like Growth Factor I (hIGF-I) #8917

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Source

Recombinant human IGF-I (hIGF-I) Gly49-Ala118 (Accession #P01343) was produced in E. coli at Cell Signaling Technology.

Molecular Characterization

Recombinant hIGF-I has a Met on the amino terminus and has a calculated MW of 7,785. DTT-reduced and non-reduced protein migrate as 6 kDa polypeptides. The expected amino-terminal MGPET of recombinant hIGF-I was verified by amino acid sequencing.

Purity

>98% as determined by SDS-PAGE of 6 μg reduced (+) and non-reduced (-) recombinant hIGF-I. All lots are greater than 98% pure.

Bioactivity

The bioactivity of recombinant hIGF-I was determined in a cell proliferation assay using primary human dermal fibroblasts. The ED50 of each lot is between 2-8 ng/ml.

Coomassie Gel

Coomassie Gel

The purity of recombinant hIGF-I was determined by SDS-PAGE of 6 µg reduced (+) and non-reduced (-) recombinant hIGF-I and staining overnight with Coomassie Blue.

Bioactivity

Bioactivity

The proliferation of primary human dermal fibroblasts treated with increasing concentrations of hIGF-I was assessed. After 72-hour treatment with hIGF-I cells were incubated with a tetrazolium salt and the OD450 - OD650 was determined.

Western Blotting

Western Blotting

Western blot analysis of extracts from human dermal fibroblasts untreated or treated with hIGF-I for 10 minutes, using Phospho-Akt (Ser473) (D9E) XP® Rabbit mAb #4060 (upper) and Akt1 (C73H10) Rabbit mAb #2938 (lower).


Western Blotting

Western Blotting

Western blot analysis of extracts from MCF-7 cells, untreated or treated with hIGF-I for 10 minutes, using Phospho-Akt (Ser473) (D9E) XP® Rabbit mAb #4060 (upper) and Akt1 (C73H10) Rabbit mAb #2938 (lower).

Endotoxin

Less than 0.01 ng endotoxin/1 μg hIGF-I.

Formulation

With carrier: Lyophilized from a 0.22 μm filtered solution of 20 mM citrate, pH 3.0 containing 100 mM NaCl and 20 μg BSA per 1 μg hIGF-I. Carrier free: Lyophilized from a 0.22 μm filtered solution of 20 mM citrate, pH 3.0 containing 100 mM NaCl.

Background

Most circulating endocrine acting IGF-I is produced by hepatocytes, and paracrine or autocrine acting IGF-I is produced by defined cell types within specific tissues (1,2). Many neoplastic cells produce IGF-I, which regulates a number of cellular processes including energy metabolism, proliferation, and cell survival (3,4). IGF-I activity is regulated by one or more of the six extracellular IGF-binding proteins (IGFBPs). IGFBPs bind to IGF-I and most inhibit IGF-I binding to IGF-I receptor (IGFIR) (1,2). Some IGFBPs may increase cell responses to IGF-I. Binding of IGF-I to IGFIR activates the Akt, JNK, and Erk pathways (2). IGF-I and IGFIR are frequently expressed by cancer cells and may contribute to the proliferation and viability of a number of cancer types (1,2).

  1. Pollak, M. (2008) Nat Rev Cancer 8, 915-28.
  2. Chitnis, M.M. et al. (2008) Clin Cancer Res 14, 6364-70.
  3. Karey, K.P. and Sirbasku, D.A. (1988) Cancer Res 48, 4083-92.
  4. Small, T.W. and Pickering, J.G. (2009) J Biol Chem 284, 24684-95.

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For Research Use Only. Not For Use In Diagnostic Procedures.

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