Background: Pleomorphic adenoma (PA) is the most common benign salivary gland tumour, with PLAG1 proposed to play a critical role in its development. The true involvement of PLAG1 in tumorigenesis is not fully understood, particularly regarding its potential dual role in both promoting and inhibiting tumour progression.
Aims and Objectives: The aims of this project were to investigate the role of PLAG1 in PA by exploring its impact on downstream gene expression, identifying novel PLAG1-interacting proteins, and assessing the effect of PLAG1 on cell behaviour.
Approach: HEK293 cells were transfected with PLAG1 or a mock vector, after which transcriptomic analysis was conducted using RNA sequencing to identify altered gene expression profiles. Gene set enrichment analysis provided insights into the affected pathways. PLAG1-proximal proteins were identified through biotin-based proximity labelling, followed by IPA analysis to elucidate the interaction networks and pathways. Functional assays, including proliferation, colony formation, migration, invasion, and apoptosis assays, were performed to examine the biological impact of PLAG1 on cell behaviour.
Results: Transcriptomic analysis revealed significant changes in pathways related to extracellular matrix remodelling, growth factor binding, and signalling pathways such as Hedgehog and Wnt. IPA analysis indicated that PLAG1 interacts with key upstream regulators such as MYB and JUN, influencing tumorigenic pathways. Functional assays demonstrated increased cell proliferation and colony formation following de novo PLAG1 expression but no effect on migration or invasion was determined. The apoptosis assay yielded inconclusive results, potentially due to the short post-transfection time used for this assay.
Conclusion: The of findings of this study suggest that PLAG1 plays a multifaceted role in PA, influencing various tumorigenic processes. While it supports cell proliferation and colony formation, its effect on migration and apoptosis remains unclear. This study provides a foundation for further exploration of PLAG1's dual role and its implications in tumour progression and transformation.
