Fig. 5: SOX12 and YBX1 cooperate to promote LDHA transcriptional activation.

A GO analysis results showed that SOX12 involved in transcription and DNA binding process assessed by IP-MS in SOX12 3×Flag-overexpressing BCPAP cells. B Protein-protein docking analysis indicating that the binding potential for SOX12 and YBX1. C Co-IP assay with SOX12 or YBX1 antibody (or IgG) in BCPAP and KTC-1 cells, followed by immunoblotting of SOX12 and YBX1. D SOX12 occupancy in the vicinity of the LDHA and YBX1 promoter was assessed by CUT & Tag in SOX12 3×Flag-overexpressing BCPAP cells, YBX1 occupancy in the vicinity of the LDHA promoter was detected using public data (CistromeDB-62977). E Luciferase reporter assays showed that SOX12 transactivated YBX1 promoter activity. F ChIP-qPCR was proformed revealing that SOX12 directly binding to the promoter of YBX1. G ChIP/re-ChIP assay indicated that YBX1 and SOX12 were bound together on the same LDHA promoter. H Western blot analysis of YBX1, LDHA and EMT-related markers, including N-cadherin, Vimentin, SAMD3, P-SMAD3 in SOX12 overexpression cells with or without YBX1 interfere. I, J Migration/Invasion assays were used to analyze the effects of YBX1 interfere in SOX12 overexpressing BCPAP and KTC-1 cells. K Schematic diagram: SOX12 binds the YBX1 promoter to promote YBX1 transcription and interacts with YBX1 to the LDHA promoter to enhance the transcriptional activation of LDHA by SOX12. LDHA subsequently enhances the level of DNA acetylation in thyroid cancer cells, thereby upregulating the TGFbeta signaling pathway and enhancing epithelial mesenchymal transformation of thyroid cancer and promoting metastasis. P values were determined using a two-tailed unpaired Student’s t test. (*p < 0.05, **p < 0.01, ***p < 0.001).