β2 Microglobulin mediated cell signaling promotes human prostate, breast, lung and renal cancer growth in mice

4822β2-Microglobulin (β2M), a soluble factor secreted by cancer and host inflammatory cells, is associated with the presentation of heavy chain major histocompatibility complex (MHC) class I. In this communication, we characterized an unexpected role of β2M as a growth factor and signaling molecule in solid tumors. We showed β2M increased cell motility, migration and invasion in human tumor cells and promoted their epithelial to mesenchymal transition. β2M-mediated cell signaling promoted the growth, survival and osteomimicry of human prostate, breast, lung and renal cancer cells. We overexpressed β2M in human prostate (C4-2B), breast (MCF-7), renal (SN12C) and lung (H358) cancer cell lines using an expression plasmid cDNA encoding β2M (control cells were stably tranfected with neo expression construct) and correlated the levels of β2M expression with the anchorage-dependent and -independent …