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Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma (KS), the most common AIDS-related malignancy. KSHV vIL-6 promotes KS development, but the exact mechanisms remain unclear. Here, we reported that KSHV vIL-6 enhanced the expression of DNA methyltransferase 1 (DNMT1) in endothelial cells,increased the global genomic DNA methylation, and promoted cell proliferation and migration. And this effect could be blocked by the DNA methyltransferase inhibitor, 5-azadeoxycytidine. We also showed that vIL-6 induced up-regulation of DNMT1 was dependent on STAT3 activation. Therefore, the present study suggests that vIL-6 plays a role in KS tumorigenesis partly by activating DNMT1 and inducing aberrant DNA methylation, and it might be a potential target for KS therapy.

miRNAs play important roles in lung adenocarcioma (LADC) progression. We previously found that miR-1290 expression was upregulated in LADC tissue and serum samples from patients with LADC, and correlated with prognosis. However, the biological role of miR-1290 in LADC and mechanism of such role are poorly understood. Here, we found that miR-1290 overexpression promoted LADC cell proliferation, cell cycle progression and invasion, while suppressing cell apoptosis in vitro. Furthermore, miR-1290 promoted tumor growth, invasion and metastasis in vivo. miR-1290 downregulated suppressor of cytokine signaling 4 (SOCS4) at both the mRNA and protein levels by targeting SOCS4. Reduced SOCS4 level reversed the inhibitory effect of miR-1290 downregulation on cell proliferation and invasion. miR-1290 activated the JAK/STAT3 and PI3K/AKT signaling pathways by targeting SOCS4. An inverse correlation was observed between miR-1290 and SOCS4 expression in LADC tissues. Clinicopathological characteristics analysis showed that SOCS4 expression was negatively associated with higher clinical stage and lymph node metastasis. These observations suggest that miR-1290 promotes LADC cell proliferation and invasion by targeting SOCS4.

Background: In recent years, tRFs(transfer RNA-Derived Fragments) and transfer RNADerived Stress-induced RNAs (or tRNA halves) have been shown to have vital roles in cancer biology. We aimed to reveal the expression profile of tRNA-derived fragments in breast cancer tissues in the study, and to explore their potential as biomarkers of breast cancer. Methods: We characterized the tRNA-derived fragments expression profile from 6 paired clinical breast cancer tissues and adjacent normal samples. Then we selected 6 significantly expressed tRNAderived fragments and screened the genes for validation by using Quantitative Real-time PCR. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes biological pathway were finally analyzed. Results: We found 30 differentially expressed tRNA-derived fragments across our dataset, out of which 17 were up-regulated, and 13 were down-regulated. Compared with 16 clinical breast cancer tissues and adjacent normal tissues by qPCR, the results demonstrated that tRF-32-Q99P9P9NH57SJ (FC = -2.6476, p = 0.0189), tRF-17-79MP9PP (FC = -4.8984, p = 0.0276) and tRF-32- XSXMSL73VL4YK (FC = 6.5781, p = 0.0226) were significantly expressed in breast cancer tissues (p < 0.001). tRF-32-XSXMSL73VL4YK was significantly up-regulated, and tRF-32- Q99P9P9NH57SJ and tRF-17-79MP9PP were significantly down-regulated in which the expression patterns were similar to the sequencing results. The top ten significant results of GO and KEGG pathways enrichment analysis were presented. Conclusion: Our studies have demonstrated that there were significantly expressed tRNA-derived fragments in breast cancer tissues. They are hopefully to become biomarkers and would be valuable researches in this area.

tRNA derivatives have been identified as a new kind of potential biomarker for cancer. Previous studies have identified that there were 30 differentially expressed tRNAs derivatives in breast cancer tissue with the high-throughput sequencing technique. This study aimed to investigate the possible biological function and mechanism of tRNA derivatives in breast cancer cells. One such tRF, a 5’-tRF fragment of tRF-17-79MP9PP (tRF-17) was screened in this study, which is processed from the mature tRNA-Val-AAC and tRNA-Val-CAC. tRF-17 with significantly low expression in breast cancer tissues and serum. The level of tRF-17 differentiated breast cancer from healthy controls with sensitivity of 70.4% and specificity of 68.4%. Overexpression of tRF-17 suppressed cells malignant activity. THBS1 (Thrombospondin-1) as a downstream target of tRF-17, and reduction of THBS1 expression also partially recovered the effects of tRF-17 inhibition on breast cancer cell viability, invasion and migration. Besides, THBS1, TGF-β1, Smad3, p-Smad3 and epithelial-to-mesenchymal transition related genes N-cadherin, MMP3, MMP9 were markedly down-regulated in tRF-17 overexpressing cells. Moreover, tRF-17 attenuated the THBS1-mediated TGF-β1/Smad3 signaling pathway in breast cancer cells. In general, the tRF-17/THBS1/TGF-β1/smad3 axis elucidates the molecular mechanism of breast cancer cells invasion and migration and could lead to a potential therapeutic target for breast cancer.

Triple-negative breast cancer (TNBC) is a highly metastatic breast cancer subtype, and the primary systemic treatment strategy involves conventional chemotherapy. DC-STAMP domain containing 1-antisense 1 (DCST1-AS1) is a long non-coding RNA that promotes TNBC migration and invasion. Studying the role of DCST1-AS1 in promoting epithelial-mesenchymal transition (EMT) and chemoresistance will provide a new strategy for TNBC therapy. In the present study, we found that DCST1-AS1 regulates the expression or secretion of EMT-related proteins E-cadherin, snail family zinc finger 1 (SNAI1), vimentin, matrix metallopeptidase 2 (MMP2), and matrix metallopeptidase 9 (MMP9). Interference with DCST1-AS1 impaired TGF-β-induced TNBC cell invasion and migration. DCST1-AS1 directly binds to ANXA1 in BT-549 cells and affects the expression of ANXA1. DCST1-AS1 enhances TGF-β/Smad signaling in BT-549 cells through ANXA1 to promote EMT. The combination of DCST1-AS1 and ANXA1 also contributes to enhancement of the resistance of BT-549 cells to doxorubicin and paclitaxel. In conclusion, DCST1-AS1 promotes TGF-β-induced EMT and enhances chemoresistance in TNBC cells through ANXA1, and therefore represents a potentially promising target for metastatic breast cancer therapy.

MiR-145 could inhibit invasion and migration of lung adenocarcinoma cell lines by directly targeting N-cadherin.

Long non-coding RNAs (lncRNA) have been identified as key regulators of tumorigenesis and development. We aim to explore the biological functions and molecular mechanisms of lncRNA MIR200CHG in breast cancer. We found that MIR200CHG is highly expressed in breast cancer tissues and is related to the tumor size and histopathological grade. In vitro and in vivo experiments confirmed that MIR200CHG can promote breast cancer proliferation, invasion, and drug resistance. MIR200CHG directly binds to the transcription factor Y-box binding protein-1 (YB-1), and inhibits its ubiquitination and degradation. MIR200CHG regulates YB-1 phosphorylation at serine 102, thereby affecting the expression of genes related to tumor cell proliferation, apoptosis, invasion, and drug resistance. Additionally, MIR200CHG partially affects the expression of miR-200c/141-3p encoded by its intron region. Therefore, MIR200CHG can promote the proliferation, invasion, and drug resistance of breast cancer by interacting with and stabilizing YB-1, and has the potential to become a target for breast cancer treatment.