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Chandrani Chattopadhyay, Scott E. Woodman, Bita Esmaeli, Elizabeth A. Grimm; Targeting IGF-1R In Uveal Melanoma Cells. Invest. Ophthalmol. Vis. Sci. 2012;53(14):3396.
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Uveal melanoma is the most frequent primary intraocular cancer in adults. Metastasis is unique being blood borne and preferentially in the liver. The mechanism responsible for this liver homing is mostly unknown. The growth factors synthesized in the liver have been hypothesized to play an important role. We are very interested in exploring such factors and their receptors that may contribute to liver metastasis in uveal melanoma. Insulin-like Growth factor 1 (IGF-1) is one of the major growth factors secreted by the liver as an endocrine hormone. Its receptor, IGF-1R, has been detected in uveal melanoma tumors and has also been reported to be prognostically relevant in this disease. We have studied the role of IGF-1R in Akt and Erk1/2 activation, cell migration and also attempted to target IGF-1R in these cells.
RT PCR and Western blotting were employed to detect IGF-1R mRNA and protein in a panel of 11 human uveal melanoma cell lines. We also tested IGF-1 secretion from these lines with ELISA. These lines included 5 with GNAQ mutation and 1 expressing GNA11. IMC-A12, a Human IgG1 monoclonal antibody to the IGF-1R, from IMCLONE, was used to target IGF-1R in these cell lines. We determined its effect on cell proliferation by MTT assays, its effect on c-Met dependent downstream signaling by Western blots for chosen molecular markers, its effect on cell migration in a modified in vitro Boyden chamber migration assay.
Detectable levels of IGF-1R mRNA were found in all 11 uveal melanoma cells lines tested and varying levels of IGF-1R protein was also observed in all lines. Phosphorylation of IGF-1R was induced on treatment of cells with IGF-1. In addition, Akt and Erk1/2 activation downstream to the observed IGF-1R activation was also detected. IMC-A12 antibody treatment against IGF-1R was able to block IGF-1R activation in uveal melanoma cells. Such inhibition also resulted in reduced Akt and Erk1/2 phosphorylation and reduced cell migration in response to 10% FBS.
Blocking IGF-1R with a monoclonal antibody IMC-A12 resulted in inhibition of IGF-1R activation and inhibition of downstream Akt and Erk1/2 phosphorylation in uveal melanoma cells. Cell migration in response to 10% FBS was also reduced post IMC-A12 treatment. Thus IGF-1R targeting in uveal melanoma cells may result in decreased cell survival/proliferation and metastasis. It can therefore develop into a suitable targeted therapy option for uveal melanoma patients.
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