tRF-3019A/STAU1/BECN1 axis promotes autophagy and malignant progression of colon cancer

Background

Tumor incidence, progression, and metastasis may be linked to the aberrant levels of novel non-coding RNA tRNA-derived fragments (tRFs). Uncertainty surrounds the role and possible mechanism of tRF-3019 A in causing colon cancer to proceed malignantly.

Methods

By using qRT-PCR, transcription levels of tRF-3019 A were found in colon cancer cell lines and clinical samples. Locked nucleic acid (LNA)-tRF-3019 A or small molecule mimic was utilized to control the levels of tRF-3019 A in cells, and the CCK8 test was employed to assess the cells' capacity for proliferation. The rate of cell migration and invasiveness were assessed using the Transwell Assay. GFP-LC3B formation was seen using fluorescence microscopy, and autophagy-related protein expression was found using western blot analysis. The interactions between STAU1 and BECN1 and between tRF-3019 A and STAU1 were confirmed by RNA pull-down assay and RNA immunoprecipitation analyses. The mRNA and protein expression of STAU1 and BECN1 were found using qRT-PCR and western blot (WB). A xenograft tumor model was constructed to observe the growth of mouse tumors. qRT-PCR was used to detect the transcription levels of tRF-3019 A, STAU1, and BECN1, while WB was used to detect the expression of STAU1, BECN1, autophagy-related proteins, and epithelial-mesenchymal transition (EMT) -related proteins in tumor tissues.

Results

In colon cancer tissues and cells, tRF-3019 A was overexpressed, and by triggering autophagy, it may encourage cell division, migration, and invasion. From a mechanistic perspective, tRF-3019 A competitively bound to the STAU1 protein with BECN1 mRNA, thereby enhancing the stable expression of the autophagy-related protein BECN1. In the model of xenograft tumor mice with knockdown of STAU1, blocking tRF-3019 A led to a substantial decrease in the pace of tumor development, a reduction in the expression of EMT-related proteins and autophagy, and an inhibition of autophagy.

Conclusion

tRF-3019A activated tumor cell autophagy and promoted the malignant progression of colon cancer by competitively binding to the STAU1 protein with BECN1 mRNA.