Figure 9.

The schematic of the THOC‐mediated stemness enhancement and radioresistance in TNBC. The export of mRNA from the nucleus to the cytoplasm is a key step in protein synthesis, which is essential for all living eukaryotic cells. The THOC is a key component in the formation of cotranscription that messenger ribonucleoparticles can be transported into the cytoplasm for translation. THOC2 and THOC5, as the backbone protein and specific adaptor for the THOC, respectively, play a vital role in maintaining the protein expression of pluripotent transcription factors and the switching of embryonic stem cell differentiation and proliferation. In this study, we found that radioresistant TNBC can employ this mechanism via upregulating the protein expression of THOC2 and THOC5 to promote the THOC‐mediated spliced mRNA efflux, increase the translation and protein synthesis of NANOG and SOX2, and enhance the stem‐like properties of TNBC cells. The upregulation of NANOG and SOX2 gene expression also provides a prerequisite for this mechanism. The enhanced stemness thus confers TNBC cells a survival advantage upon RT‐induced oxidative stress injury and apoptosis. (This figure was created with Biorender.com)