Abstract
Abstract
Malignant melanoma is an aggressive malignancy of the melanocytes. The incidence rates for melanoma are steadily increasing and melanoma has now become the most common form of cancer among young adults between the ages of 25 and 29 years old. Because melanomas are highly resistant to the majority of therapies, the survival rate for patients with metastatic disease is less than 15%. There is a clear need for novel more effective therapies.
Identification of the signaling pathways that are altered in melanoma provides opportunities for the development of novel targeted therapies. The Notch pathway is an evolutionary conserved signaling cascade that has an essential role in embryonic development but is inappropriately active in various types of cancers. Studies from our group and others have shown that hyper activation of Notch1 is an early event in melanocyte transformation and modulates both growth and metastasis in melanoma.
We have found a new interaction between Notch1 and neuregulin1 (NRG1) signaling that plays a role in melanoma. Neuregulin1 is the ligand for ERBB3, a member of the Epidermal Growth Factor family of receptors that are involved in the genesis and progression of a number of cancers. Notch1 binds to the NRG1 promoter thereby modulating NRG1 expression and consequently the activation of the ERBB3 pathway. Inhibition of either NRG1 or ERBB3 activity in melanoma cells lead to cell growth inhibition and tumor growth delay similar to Notch1 inhibition. Mechanistically, these effects are dependent on the accumulation of p27 following either NRG1 or Notch1 down regulation. In addition, we find that NRG1/ERBB3 signaling influences Notch1 activation likely through the modulation of the Notch ligands Jaggged-1 (JAG-1) and Delta like 3 (Dll3), thus providing a feed forward regulatory loop linking the two pathways.
Taken together, our findings underline a new, previously undescribed interaction between Notch1 and NRG1/ERBB3 in melanoma. Our goal is to investigate the mechanisms by which these two oncogenic signaling pathways intersect to promote a highly aggressive disease phenotype and to provide experimental evidence that the targeting of Notch and ERBB signaling is a tractable and effective approach to treat forms of melanoma that may be resistant to current available therapies.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-9. doi:10.1158/1538-7445.AM2011-LB-9
