Downregulation of miR-499a-5p Predicts a Poor Prognosis of Patients With Non-Small Cell Lung Cancer and Restrains the Tumorigenesis by Targeting Fibroblast Growth Factor 9

Ferroptosis contributes to the progression of female-specific neoplasms, from breast cancer to gynecological malignancies in a manner regulated by non-coding RNAs: Mechanistic implications

Ferroptosis, a recently identified type of non-apoptotic cell death, triggers the elimination of cells in the presence of lipid peroxidation and in an iron-dependent manner. Indeed, ferroptosis-stimulating factors have the ability of suppressing antioxidant capacity, leading to the accumulation of reactive oxygen species (ROS) and the subsequent oxidative death of the cells. Ferroptosis is involved in the pathophysiological basis of different maladies, such as multiple cancers, among which female-oriented malignancies have attracted much attention in recent years. In this context, it has also been unveiled that non-coding RNA transcripts, including microRNAs, long non-coding RNAs, and circular RNAs have regulatory interconnections with the ferroptotic flux, which controls the pathogenic development of diseases. Furthermore, the potential of employing these RNA transcripts as therapeutic targets during the onset of female-specific neoplasms to modulate ferroptosis has become a research hotspot; however, the molecular mechanisms and functional alterations of ferroptosis still require further investigation. The current review comprehensively highlights ferroptosis and its association with non-coding RNAs with a focus on how this crosstalk affects the pathogenesis of female-oriented malignancies, from breast cancer to ovarian, cervical, and endometrial neoplasms, suggesting novel therapeutic targets to decelerate and even block the expansion and development of these tumors.

MicroRNA Landscape in Endometrial Carcinomas in an Asian population: Unraveling Subtype-Specific Signatures

MicroRNAs (MiRNAs) are small, non-coding RNA molecules that function in RNA silencing and post-transcriptional regulation of gene expression. We analyzed the differential expression of miRNAs in 119 endometrial carcinomas, measuring their expression in histological subtypes, molecular subtypes, and tumors with CTNNB1 mutations. Tumors were subdivided into histological and molecular subtypes as defined by The Cancer Genome Atlas. The expression levels of 352 miRNAs were quantified using the PanoramiR panel. Mir-449a, mir-449b-5p, and mir-449c-5p were the top three miRNAs showing increased expression in both endometrioid and de-differentiated carcinomas but were not significantly increased in serous and clear cell carcinomas. The miRNAs with the most increased expression in serous and clear cell carcinomas were miR-9-3p and miR-375, respectively. We also identified 62 differentially expressed miRNAs among different molecular subtypes. Using sequential forward selection, we built subtype classification models for some molecular subtypes of endometrial carcinoma, comprising 5 miRNAs for MMR-deficient tumors, 10 miRNAs for p53-mutated tumors, and 3 miRNAs for CTNNB1-mutated tumors, with areas under curves of 0.75, 0.85, and 0.78, respectively. Our findings confirm the differential expression of miRNAs between various endometrial carcinoma subtypes and may have implications for the development of diagnostic and prognostic tools.

TMEM189 as a target gene of MiR-499a-5p regulates breast cancer progression through the ferroptosis pathway

MicroRNA (miR)-499a-5p has been reported to regulate the progression of various tumours. However, the role of miR-499a-5p in breast cancer is unclear. The purpose of this study was to investigate the role and mechanism of miR-499a-5p in breast cancer. The growth effect of miR-499a-5p on breast cancer cells was investigated by the CCK-8 assay, wound healing assay and Transwell invasion assay. The luciferase activity assay was used to verify the downstream targets of miR-499a-5p. The levels of GSH, MDA, and ROS were detected by kits. Quantitative real-time PCR and Western blot were used to determine the expression levels of TMEM189, COX-2, GPX4, and other related genes in cells. miR-499a-5p was down-regulated in MDA-MB-231 cells and was shown to reduced the viability, migration and invasion of MDA-MB-231 cells. Further studies revealed that TMEM189 is a target of miR-499a-5p. miR-499a-5p inhibited breast cancer cell growth by downregulating TMEM189. Furthermore, the down-regulation of TMEM189 promotes ferroptosis in breast cancer cells. The low expression of TMEM189 inhibited the development of breast cancer through the ferroptosis pathway. We have demonstrated for the first time that miR-499a-5p inhibits breast cancer progression by targeting the TMEM189-mediated ferroptosis pathway.

High-Throughput Analysis Reveals miRNA Upregulating α-2,6-Sialic Acid through Direct miRNA-mRNA Interactions

Chemical biology has revealed the importance of sialic acids as a major signal in physiology and disease. The terminal modification α-2,6-sialic acid is controlled by the enzymes ST6GAL1 and ST6GAL2. Dysregulation of this glycan impacts immunological recognition and cancer development. microRNAs (miRNA, miR), noncoding RNAs that downregulate protein expression, are important regulators of glycosylation. Using our recently developed high-throughput fluorescence assay (miRFluR), we comprehensively mapped the miRNA regulatory landscape of α-2,6-sialyltransferases ST6GAL1 and ST6GAL2. We found, contrary to expectations, the majority of miRNAs upregulate ST6GAL1 and α-2,6-sialylation in a variety of cancer cells. In contrast, miRNAs that regulate ST6GAL2 were predominantly downregulatory. Mutational analysis identified direct binding sites in the 3'-untranslated region (UTR) responsible for upregulation, confirming it is a direct effect. The miRNA binding proteins AGO2 and FXR1 were required for upregulation. Our results upend common assumptions surrounding miRNA, arguing that upregulation by these noncoding RNA is common. Indeed, for some proteins, upregulation may be the dominant function of miRNA. Our work also suggests that upregulatory miRNAs enhance overexpression of ST6GAL1 and α-2,6-sialylation, providing another potential pathway to explain the dysregulation observed in cancer and other disease states.

TTN-AS1 delivered by gastric cancer cell-derived exosome induces gastric cancer progression through in vivo and in vitro studies

Extracellular communication within the tumor microenvironment exerts critical functions in tumor progression. Moreover, exosomes are capable of packaging into long non-coding RNAs (lncRNAs) to regulate extracellular communication. We tried to discuss the role of exosomal lncRNA TTN-AS1 and its molecular mechanism on gastric cancer (GC) progression. Bioinformatics analysis depicted increased TTN-AS1 in GC which shared correlation with poor prognosis. Clinical tissue and cellular experiments also confirmed the elevation of TTN-AS1 in GC tissues and cells. GC cell (AGS)-derived Exo could be uptake by NCI-N87 cells to induce malignant features of GC cells. Functionally, TTN-AS1 could upregulate ZEB1 expression by binding to miR-499a-5p. In addition, in vitro experiments demonstrated that ZEB1 targeted and activated CDX2 transcription and promoted CDX2 expression; silencing CDX2 inhibited malignant phenotypes of AGS and NCI-N87 cells. Furthermore, Exo-TTN-AS1 promoted GC cell growth and migration by promoting CDX2 expression. Exosomal TTN-AS1 from GC cells could also promote metastasis of GC in vivo. In conclusion, our findings provided evidence describing that exosomes derived from GC cells transferred TTN-AS1 to GC cells, which aggravate GC through the miR-499a-5p/ZEB1/CDX2 axis. 1. Exo derived from GC cells promotes the growth and metastasis of GC cells by carrying TTN-AS1. 2. TTN-AS1 acts as a ceRNA to adsorb miR-499a-5p to regulate the expression of ZEB1. 3. ZEB1 targets and activates CDX2 transcription. 4. GC cell-derived Exo-TTN-AS1 enhances the growth and metastasis of GC cell xenografts in vivo.

LncRNA GIHCG promoted the proliferation and migration of renal cell carcinoma through regulating miR-499a-5p/XIAP axis

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LncRNA GIHCG facilitated the proliferation and migration while suppressed apoptosis of RCC cells.

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LncRNA GIHCG directly sponged miR-499a-5p and down-regulated its expression.

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MiR-499a-5p negatively regulated XIAP expression.

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LncRNA GIHCG knockdown inhibited the growth and metastasis of RCC in nude mice.

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LncRNA GIHCG contributed to the development of RCC through miR-499a-5p/XIAP axis.

Background

Our previous study demonstrated that lncRNA GIHCG is upregulated in renal cell carcinoma (RCC) and that knockdown of lncRNA GIHCG suppresses the proliferation and migration of RCC cells. However, the mechanism of lncRNA GIHCG in RCC needs further exploration.

Methods

The proliferation, cell cycle, migration, and apoptosis of RCC cells were tested using CCK-8, flow cytometry, wound healing and Annexin-V/-FITC/PI flow cytometry assays, respectively. Dual-luciferase reporter and RNA pull-down or RNA immunoprecipitation assays (RIPs) were performed to analyze the interactions among lncRNA GIHCG, miR-499a-5p and XIAP. A tumour xenograft study was conducted to verify the function of lncRNA GIHCG in RCC development in vivo.

Results

Knockdown of lncRNA GIHCG inhibited cell proliferation and migration and induced G0/G1 arrest while promoting apoptosis. Overexpression of lncRNA GIHCG led to the opposite results. LncRNA GIHCG sponged miR-499a-5p and downregulated its expression in RCC cells. MiR-499a-5p overexpression suppressed RCC cell growth. MiR-499a-5p targeted XIAP and inhibited its expression. LncRNA GIHCG knockdown reduced the growth of tumour xenografts in vivo and the expression of XIAP while increasing miR-499a-5p levels.

Conclusion

LncRNA GIHCG accelerated the development of RCC by targeting miR-499a-5p and increasing XIAP levels.

Long non-coding RNA LINC01018 inhibits the progression of acute myeloid leukemia by targeting miR-499a-5p to regulate PDCD4

Acute myeloid leukemia (AML) is a highly heterogeneous disease with a very high mortality rate. In recent years, an increasing number of studies have proven that long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) may serve as useful biomarkers in various cancer types. However, the mechanism of LINC01018 and miR-499a-5p in AML requires further investigation. The mRNA expression of LINC01018, miR-499a-5p and PDCD4 in AML tissues and cells was detected using reverse transcription-quantitative polymerase chain reaction. Cell proliferation was measured using Cell Counting kit-8 and EdU assays. Cell apoptosis was monitored via a TUNEL staining assay. Protein expression of PDCD4, Bax and Bcl-2 was measured using western blot analysis. The interaction between PDCD4 and LINC01018 or miR-499a-5p was verified by RNA pull-down, RIP and dual-luciferase reporter assays. LINC01018 and PDCD4 were downregulated in AML, while miR-499a-5p was upregulated. LINC01018-overexpression suppressed AML cell proliferation and induced AML cell apoptosis, while miR-499a-5p transfection reversed these effects. LINC01018 acted as a sponge of miR-499a-5p, and PDCD4 was demonstrated to be targeted by miR-499a-5p. Knockdown of miR-499a-5p suppressed AML cell proliferation and promoted AML cell apoptosis, but silencing PDCD4 abolished this effect. LINC01018 inhibited AML cell growth by modulating PDCD4 through suppression of miR-499a-5p, providing a feasible theoretical basis for the treatment of AML.