Bad to the bone: An RNA-sequencing study identifying a role for IKKα in osteosarcoma cell division and progression

Description

Introduction: Osteosarcoma (OS) is the most prevalent primary malignant bone tumour generally made up of osteoblasts and is diagnosed in one to three individuals per million people every year (1-3). Despite research efforts, there has been little improvement to osteosarcoma treatment and prognosis in the last 30 years (4). Given these marginal improvements, research at a molecular level is imperative to enable discovery of therapeutic drug targets for osteosarcoma (5).
Methods: Our present study utilises short-read RNA-sequencing techniques (Illumina) to a human OS cell line, U2OS with and without IKK deletion by CRISPR-Cas9 knockdown, and in the absence or presence of IL-1 (10 ng/mL) stimulation for 8 or 24 hours (n=3). Following RNA-sequencing analysis, we further validated gene expression of genes of interest by RT-qPCR and at protein level by utilising immunofluorescence techniques and SDS-PAGE and western blotting.
Results: Our findings highlight that IKK knockdown significantly decreases expression of cell division genes associated with OS progression, including AURKA, AURKB, TPX2, BIRC5, GTSE1, E2F2, FOXM1 and SPC24 (****p<0.0001). Interestingly, IKK knockdown increased osteoclast-associated receptor (OSCAR) gene expression (****p<0.0001), which is a central receptor in bone degradation processes. Osteoclast activity is associated with decreased OS-derived metastasis, and hence this implies a role for IKKα in promoting metastasis. Additionally, with IL-1β (10 ng/mL) stimulation for 8 hours, we identified that there are several IL-1β-dependent, IKKα-dependent genes associated with OS tumour progression including CXCL5 and GAS7 (6). These results were validated in the laboratory by RT-qPCR. This reveals an important role for IKKα in osteogenesis mediated by the CXCR2 axis and GAS7 (Figure 1).
Conclusion: Overall, IKKα appears to play a role in osteogenesis, a key feature in OS cell proliferation and a role in downregulating bone degradation. However, validating these results in OS patient samples would be required before considering IKKα as a viable therapeutic drug target in OS.

Period	3 Sept 2024
Event title	6th European NF-kappaB Workshop
Event type	Conference
Location	Marburg, GermanyShow on map