Progression of breast cancers often depends on hormones among which human growth hormone is prominently involved in breast cancer progression. Earlier studies have reported constitutive activation of nuclear factor-κB, a key regulator of growth hormone receptor-mediated signaling pathway in breast carcinoma, but the precise molecular mechanisms are still elusive. In this study, we investigated the effect of human growth hormone on nuclear factor-κB activation and epithelial-mesenchymal transition in breast carcinoma. Our results explored that autocrine production of human growth hormone enhances cellular proliferation by the activation of nuclear factor-κB (65 kDa) and downregulation of E-cadherin expression. Furthermore, enhanced nuclear factor-κB expression significantly increases cell proliferation and diminishes apoptosis in MCF-7 cell line. Increased expression of nuclear factor-κB significantly enhances mammary carcinoma cell migration and invasion stimulated by autocrine human growth hormone, which results in epithelial-mesenchymal transition of MCF-7 cells. In conclusion, our study revealed the influence of human growth hormone on nuclear factor-κB activity and epithelial-mesenchymal transition in mammary carcinoma. Our findings will help to understand molecular role of "growth hormone-nuclear factor-κB axis" in mammary carcinogenesis which may facilitate the discovery of suitable pathway inhibitors for disease treatment.
Keywords: Breast cancer; apoptosis; autocrine growth hormone; epithelial–mesenchymal transition; nuclear factor-κB.