Antibiotic-disrupted ribosome biogenesis facilitates tumor chemokine superinduction.

Upon exposure to internal or external stressors, ribosomes stand sentinel via modulation of ribosome assembly and protein translation. Ribosome-dependent cellular dysfunctions have been associated with pathophysiological processes during inflammation and tumorigenesis. In the present study, ribosome biogenesis was assessed to determine its effects on tumor chemokines, potentially contributing to cancer cell malignant features. In particular, ribosome biogenesis inhibition by antibiotic actinomycin D (ActD) enhanced the expression of chemokines in intestinal cancer cells under endoplasmic reticulum stress that governs multiple pro-tumoral reprogramming. Mechanistically, ribosome biogenesis inhibition superinduced proinflammatory chemokines via transcriptional and post-transcriptional regulation. Moreover, ribosomal stress-responsive p53 and its target macrophage inhibitory cytokine 1 (MIC-1) mediated chemokine superinduction by activating TGF-β-activated kinase 1 (TAK-1) and nuclear factor-kappa B (NF-κB) in intestinal cancer cells. Cancer cell-based regulation of chemokine induction via MIC-1 signaling was verified using clinical transcriptome datasets. Clinical tumor tissue-derived MIC-1 was a positive regulator of chemokines and genes involved in the ribosome biogenesis pathway, supporting the in vitro assessments. Moreover, MIC-1-correlated chemokine expressions predicted poor prognoses in patients with colorectal cancer. Ribosome-based chemokine regulation via MIC-1 signaling would provide novel insights into translational interventions against malignant inflammatory insults.