Ribosome Incorporation Induces EMT-like Phenomenon with Cell Cycle Arrest in Human Breast Cancer Cell.

Although ribosomes are generally known to be a translational machinery, some ribosomal proteins also have accessory functions involving early development and differentiation. Previously, we reported that ribosome incorporation into human dermal fibroblasts generated embryoid body-like cell clusters, altered cellular fate, and differentiated into cells of all 3 germ layers. However, the molecular phenomena induced by ribosome incorporation in the cell remained unknown. Here, we demonstrate that ribosome incorporation into human breast cancer cell MCF7 leads to ribosome-induced cell clusters (RICs) formation accompanying with epithelial-mesenchymal transition (EMT)-like gene expression. Following ribosome incorporation, MCF7 cells cease proliferation, which is caused by inhibition of cell cycle transition from G0 to G1 phase. Further, MCF7 RICs show induced expression of EMT markers, TGF-β1 and Snail along with autophagy markers and tumor suppressor gene p53. These findings indicate that the incorporation of ribosome into cancer cells induces an EMT-like phenomenon and changes the cancer cell characteristics.