Dynamic Signature of tRNA-Derived Small RNAs in Cancer Pathogenesis as a Promising Valuable Approach

Quantitative and qualitative detection of tRNAs, tRNA halves and tRFs in human cancer samples: Molecular grounds for biomarker development and clinical perspectives

Transfer RNAs (tRNAs) are small non-coding RNAs playing a central role during protein synthesis. Besides translation, growing evidence suggests that in many contexts, precursor or mature tRNAs can also be processed into smaller fragments playing many non-canonical regulatory roles in different biological pathways with oncogenic relevance. Depending on the source, these molecules can be classified as tRNA halves (also known as tiRNAs) or tRNA-derived fragments (tRFs), and furtherly divided into 5'-tRNA and 3'-tRNA halves, or tRF-1, tRF-2, tRF-3, tRF-5, and i-tRF, respectively. Unlike DNA and mRNA, high-throughput sequencing of tRNAs is challenging, because of technical limitations of currently developed sequencing methods. In recent years, different sequencing approaches have been proposed allowing the quantification and identification of an increasing number of tRNA fragments with critical functions in distinct physiological and pathophysiological processes. In the present review, we discussed pros and cons of recent advances in different sequencing methods, also introducing the expanding repertoire of bioinformatics tool and resources specifically focused on tRNA research and discussing current issues in the study of these small RNA molecules. Furthermore, we discussed the potential value of tRNA fragments as diagnostic and prognostic biomarkers for different types of cancers.

The role of IgG4 in systemic lupus erythematosus: Implications for pathogenesis and therapy

Immunoglobulin (Ig) G4 has a distinctive nature, and its involvement in autoimmune disorders is a subject of ongoing debate and uncertainty. A growing body of evidence indicates that IgG4 may play a pathogenic role in the development of systemic lupus erythematosus (SLE). The IgG4 autoantibodies have the capability to bind autoantigens in a competitive manner with other Ig classes, thereby forming immune complexes (ICs) that are noninflammatory in nature. This is due to the low affinity of IgG4 for both the Fc receptors and the C1 complement molecule, which results in a diminished inflammatory response in individuals with SLE. The present study aims to elucidate the significance of IgG4 in SLE. The present discourse pertains to the nascent and suggested modalities through which IgG4 might participate in the pathogenesis of SLE and the potential ramifications for therapeutic interventions in SLE.

The crosstalk between autophagy and myeloid-derived suppressor cell responses in cancer

The development of cancers is aided by the accumulation of myeloid-derived suppressor cells (MDSCs) within tumors, which are highly effective at suppressing anti-tumor immune responses. Direct cell-to-cell interaction and the production of immunosuppressive mediators have both been proposed as pathways for MDSC-mediated suppression of anti-tumor immune responses. The majority of current cancer treatments focus on altering the development and activity of MDSCs so that they have more of an immunogenic character. Autophagy is a catabolic system that contributes to the breakdown of damaged intracellular material and the recycling of metabolites. However, depending on the stage of tumor growth, autophagy can play both a prophylactic and a therapeutic function in carcinogenesis. However, several indirect lines of research have indicated that autophagy is a significant regulator of MDSC activity. The purpose of this work was to outline the interactions between MDSC and autophagy in cancer.

The crosstalk between intestinal bacterial microbiota and immune cells in colorectal cancer progression

Different types of cells that are involved in tumor immunity play a significant part in antitumor therapy. The intestinal microbiota consist of the trillions of diverse microorganisms that inhabit the gastrointestinal tract. Recently, much emphasis has been paid to the link between these symbionts and colorectal cancer (CRC). This association might be anything from oncogenesis and cancer development to resistance or susceptibility to chemotherapeutic medicines. Cancer patients have a significantly different microbial composition in their guts compared to healthy persons. The microbiome may play a role in the development and development of cancer through the modulation of tumor immunosurveillance, as shown by these studies; however, the specific processes underlying this role are still poorly understood. This review focuses on the relationship between the intestinal bacterial microbiota and immune cells to determine how the commensal microbiome influences the initiation and development of CRC.

Relationship Between Low Expressions of tRNA-Derived Fragments with Metastatic Behavior of Colorectal Cancer

PURPOSE

Colorectal cancer (CRC) is one of the most commonly diagnosed malignant tumors and highly heterogeneous diseases. More recently, RNA expression profiles have been used as prognostic cancer markers. In this regard, the expression of small non-coding RNAs like tRNA-derived fragments (tRFs) in tumor tissue has potential diagnostic values in metastatic cancer.

METHOD

Sixty postoperative CRC tissue samples, consisting of 30 cancers and 30 adjacent normal tissues, were collected from cancer patients. We evaluated MINTbase database to select tRNA-derived fragments. The expression levels of miR-1280, miR1308, tRNA-Val^AAC/CAC, and tRNA-Asp^GTC were measured by TaqMan quantitative reverse transcription PCR technology. Also, we have evaluated the correlation between the levels of tRFs gene expression and clinicopathological of CRC disease.

RESULT

The three tRFs derived from tRF/miR-1280, tRNA-Val^AAC/CAC, and tRNA-Asp^GTC downregulated in tumor tissues (all, p < 0.0001). These tRFs have lower expression in stage IV in comparison with stage III. The tRFs derived from tRNA-Val^AAC (p = 0.005) and tRNA-Asp^GTC (p = 0.034) showed the decreased expression in CRC patients with distant metastasis.

CONCLUSION

The present study demonstrated that low expression of tRF/miR-1280, tRNA-Val^AAC/CAC, and tRNA-Asp^GTC was significantly associated with metastatic stage and more aggressive tumor behavior of CRC disease. Our finding promising the potential of using tRFs as biomarkers for cancer diagnosis.