ABSTRACT
OBJECTIVE: LINC00205, a bidirectional lncRNA, located at human chromosome 21q22.3, was recently characterized as an oncogenic molecule contributing to cell proliferation in several cancers, including hepatocellular carcinoma (HCC). In the present study, we aim to probe the new molecular mechanism for LINC00205 controlling the proliferation of HCC cells. PATIENTS AND METHODS: The expression status of LINC00205, miR-26a-5p, as well as CDK6 in HCC tissues/cell lines was determined by quantitative real-time PCR (qPCR). The cell proliferative activity was measured by using the Cell Counting Kit (CCK)-8 assay. Flow cytometry was performed to analyze cell cycle progression and apoptosis induction. The interaction among LINC00205, miR-26a-5p and CDK6, as well as transcription efficiency of LINC00205 promoter were examined by Dual-Luciferase reporter assay. Western blot was conducted to evaluate the protein levels of CDK6 in SNU-449 cells. The direct interplay between YY1 and LINC00205 promoter was detected by ChIP-qPCR. RESULTS: LINC00205 was strongly expressed in HCC tissues and cell lines. Elevated LINC00205 expression was positively associated with worse prognosis as well as pathological grade in HCC. Suppression of LINC00205 could impede the proliferation of HCC cells by triggering the G0/G1-phase cell cycle arrest and apoptosis in vitro. Mechanistically, we illustrated that LINC00205 could accelerate the proliferation of HCC cells by boosting CDK6 expression via sponging miR-26a-5p. Moreover, we unveiled that LINC00205 could be activated by transcription factor Yin Yang-1 (YY1) as its direct downstream target. CONCLUSIONS: LINC00205, a novel YY1-modulated lncRNA, can facilitate the proliferation of HCC cells through YY1/miR-26a-5p/CDK6 pathway, and may serve as a promising diagnostic biomarker and therapeutic target for HCC.
Subject(s)
Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , MicroRNAs/genetics , RNA, Long Noncoding/genetics , Apoptosis/genetics , Carcinoma, Hepatocellular/genetics , Cell Cycle Checkpoints/genetics , Cell Line, Tumor , Cell Proliferation/genetics , Cyclin-Dependent Kinase 6/genetics , Gene Expression Regulation, Neoplastic , Humans , Liver Neoplasms/genetics , Tumor Cells, Cultured , YY1 Transcription Factor/geneticsABSTRACT
Cinnamomin, a type II ribosome-inactivating protein (RIP) isolated from the seeds of Camphora tree (Cinnamomum camphora), could not inactivate its own (autologous) ribosome. Among five RIPs (Cinnamomin A-chain, ricin A-chain, trichosanthin, gelonin, and soporin-S6) tested, only saporin-S6 could cleave the N-glycosidic bond of RNA in C. camphora ribosome to release a specific RNA fragment (R-fragment) after treatment with aniline, which was shorter than that from rat liver ribosome. The amount of saporin-S6 to inactivate C. camphora ribosome was about 1000 times higher than that required for rat liver ribosome. Extra-ribosomal factors (S-100) in the post-ribosomal supernatant could not promote RNA N-glycosidase activity of cinnamomin and gelonin to C. camphora ribosome. These results indicated that there were some changes in the microenvironments of Sarcin/Ricin domain of C. camphora ribosome that abolished the recognition and catalysis of many RIPs. In addition, the length of C. camphora 5.8S ribosomal RNA was found to be longer than that of rat 5.8S ribosomal RNA.