Expression and Diagnostic Value of tRNA-Derived Fragments Secreted by Extracellular Vesicles in Hypopharyngeal Carcinoma

Abstract

To detect the expression level of tRNA-derived fragments secreted by extracellular vesicles in hypopharyngeal cancer and explore the influence of tRNA-derived fragments on the occurrence of hypopharyngeal cancer and lung metastasis. Methods: After high-speed centrifugation, tRNA, which was extracted from the extracellular vesicles of patients with hypopharyngeal cancer and healthy subjects, was sequenced using microarrays. The expression of three differentially expressed tRNAs in hypopharyngeal cancer, healthy subjects, human normal laryngeal epithelial cells and hypopharyngeal cancer line was detected by qRT-PCR. The correlation between the upregulated tRNA, as identified by qRT-PCR, and the clinicopathological features of the non-lung metastatic patients was further analyzed. Finally, the expressions of upregulated tRNA were compared between the non-lung metastatic and lung metastatic patients. The risk factors of hypopharyngeal cancer with lung metastatic were identified by the Cox regression analysis. Results: By high-speed centrifugation, extracellular vesicles were extracted successfully. It was found that a variety of tRNAs in the extracellular vesicles from patients with hypopharyngeal cancer by sequencing. qRT-PCR validation indicated that tRF-1:30-Lys-CTT-1-M2 was significantly overexpressed in hypopharyngeal cancer patients and tumor cells, especially in lung metastatic patients. It was indicated that tRF-1:30-Lys-CTT-1-M2 overexpression was closely related to such pathological features as tumor staging, differentiation grade, smoking history and drinking history. According to the Cox regression analysis, stage III-IV, smoking history, drinking history and tRF-1:30-Lys-CTT-1-M2 overexpression were independent risk factors for metastasis of hypopharyngeal cancer. Conclusion: tRF-1:30-Lys-CTT-1-M2 was overexpressed in patients with hypopharyngeal cancer and was identified as an independent risk factor for lung metastasis. It can be used as a novel biomarker for the diagnosis and lung metastasis monitoring of hypopharyngeal cancer.

The Clinical Significance of Transfer RNAs Present in Extracellular Vesicles

“…No differences were found, however, across cancer type or HPV status. A large study by Xi et al [ 50 ] in 2021 further investigated the level of expression of extracellular-vesicle-associated tRFs from the blood plasma samples of 30 HNSCC (termed hypopharyngeal in the paper) patients with no metastasis, 30 patients with lung metastasis, and 30 healthy controls. Differential expression analysis and qPCR validation revealed a particular tRF (tRF-1:30-Lys-CTT-1-M2) to be significantly expressed in the EVs of patients with cancer, and this was additionally associated with tumour stage and grade, as well as lung metastatic risk.…”

Emerging roles of tRNA-derived fragments in cancer

“…The expression profile of tRFs in primary nasopharyngeal carcinoma was identified and two upregulated tRFs (tRF-1:28-Val-CAC-2 and tRF-1:24-Ser-CGA-1-M3) and one downregulated tRF (tRF-55:76-Arg-ACG-1-M2) were validated [ 171 ]. Another tRF, tRF-1:30-Lys-CTT-1-M2 was upregulated in hypopharyngeal cancer and identified as an independent risk factor for lung metastasis [ 100 ]. In the HNSCC, a multi-marker signature of 3 circulating sncRNAs including miRNAs, tRFs and YRNA-derived small RNAs was identified with significantly deregulated expression in patients’ sera compared with healthy controls, which could contribute to early diagnosis of HNSCC [ 196 ].…”

“…In addition, tRF-1:30-Lys-CTT-1-M2 was identified as overexpressed in plasma EVs of hypopharyngeal cancer patients and further validated in newly diagnosed cancer patients. Furthermore, a significant upregulation of tRF-1:30-Lys-CTT-1-M2 was presented in the lung metastatic hypopharyngeal cancer patients compared with the non- metastatic patients, which was considered as an independent risk factor for the metastasis of hypopharyngeal cancer [ 100 ].…”

“…On the other hand, the aberrant expression and function of specific tRFs have also been reported in various cancers, including breast cancer (BC), gastric cancer (GC), and colorectal cancer (CRC), among others (Table 1). Growing evidence demonstrate that the dysregulation of tRFs is closely related with clinicopathologic features and survival of cancer patients [98][99][100]. Functional studies indicate that tRFs are involved in various biological activities during cancer development and progression, such as tumor cell proliferation, metastasis, apoptosis and chemoresistance [101][102][103].…”

tRNA derived small RNAs—Small players with big roles

“…The expression level of a 5′ tRF from tRNA Arg (tRF-20-S998LO9D), was positively correlated with poor prognosis in a variety of cancers such as breast invasive carcinoma, head and neck squamous cell carcinoma, kidney renal clear cell carcinoma, lung squamous cell carcinoma, pheochromocytoma and paraganglioma, and uterine corpus endometrial carcinoma ( Gu et al, 2020 ; Ma and Liu, 2022 ). Specific tRFs have been suggested as predictive biomarkers and intervention targets for several types of cancers ( Sun et al, 2018 ; Xi et al, 2021 ).…”