Intermedin (adrenomedullin 2) promotes breast cancer metastasis via Src/c-Myc-mediated ribosome production and protein translation

Purpose Breast cancer is the most frequently diagnosed cancer and is the leading cause of cancer-associated mortality in women worldwide. Intermedin (IMD, also known as Adrenomedullin 2, ADM2) is an endogenous peptide that belongs to the calcitonin gene-related peptide family and has been reported to play important roles in several types of cancers, including breast cancer. In this study, we sought to investigate how IMD affects the behavior of breast cancer cells, the underlying mechanism of these effects, and whether blockade of IMD has a therapeutic effect against breast cancer. Methods Transcriptome sequencing (RNA-Seq), cell biological experiments, Western blotting, immunoprecipitation, and animal tumor models were used. Results IMD expression was significantly increased in breast cancer samples, and the IMD level was positively correlated with lymph node metastasis and Ki67 expression. Cell biological experiments showed that IMD promoted the anchorage-independent growth, migration, and invasive ability of breast cancer cells. Inhibiting IMD activity with an anti-IMD monoclonal antibody blocked these tumor-promoting effects. In addition, blockade of IMD reduced in situ tumor growth and significantly decreased lung metastasis of 4T1 breast cancer in vivo. IMD induced Src kinase phosphorylation, which triggered the transcription of c-Myc, a major oncoprotein controlling the expression of genes that encode ribosomal components. Our data suggest that IMD is involved in breast cancer cell invasion and metastasis, potentially through increasing ribosome biogenesis and protein translation via the Src/c-Myc signaling pathway. Conclusion These results suggest that IMD may be a novel target for the treatment of breast cancer.