Growth-regulated oncogene-α from oral submucous fibrosis fibroblasts promotes malignant transformation of oral precancerous cells

Background: Oral squamous cell carcinoma (OSCC) is a common human malignancy and is usually preceded by the oral precancerous lesions. Oral submucous fibrosis (OSF) is one of the oral precancerous lesions with high incidence of malignant transformation. In addition to cancer cells, cancer-associated fibroblasts in the tumor microenvironment are correlated with cancer progression, but the role of fibroblasts from OSF in tumorigenesis and progression is still unknown. Growth-regulated oncogene-α (GRO-α), a member of CXC chemokine family, is related to tumorigenesis in several cancers. In this study, we would like to explore the role of GRO-α from OSF-associated fibroblasts in oral cancer progression. Methods: We isolated primary culture fibroblasts of normal, precancerous, and tumor tissues from patients with OSCC accompanied with OSF. A cytokine array was used to screen cytokine secretions in the conditioned media of the fibroblasts. A wound healing migration assay, WST-1 cell proliferation assay, rhodamine-phalloidin staining, and soft agar colony formation assay were used to investigate the effects of GRO-α on a dysplastic oral keratinocyte cell line (DOK) cell migration, growth, and anchorage-independent growth. Results: GRO-α was identified to be increased in conditioned media of OSF-associated fibroblasts. GRO-α promotes DOK cells proliferation, migration, and anchorage-independent growth through enhancing the EGFR/ERK signaling pathway, F-actin rearrangement, and stemness properties, respectively. Moreover, GRO-α neutralizing antibodies downregulated the conditioned medium-induced cell proliferation and migration of DOK. Conclusion: GRO-α from OSF-associated fibroblasts paracrinally promotes oral malignant transformation and significantly contributes to OSCC development.