Exogenous Let-7a-5p Induces A549 Lung Cancer Cell Death Through BCL2L1-Mediated PI3Kγ Signaling Pathway

Gong

et al. 2020

CMAR

Background: Paclitaxel (PTX) is one of the widely used chemotherapy drugs in breast cancer (BC) treatment. Unfortunately, the survival rate of metastatic BC patients remains poor due to PTX resistance. Therefore, uncovering the underlying mechanism behind the PTX resistance of BC cells is crucial for BC therapy. Methods: The enrichment of circular RNA ATP binding cassette subfamily B member 10 (circ-ABCB10), let-7a-5p and dual specificity phosphatase 7 (DUSP7) was measured by quantitative real time polymerase chain reaction (qRT-PCR) in PTX-resistant and PTXsensitive BC tissues and cells. Chemoresistance, apoptosis, invasion and autophagy of BC cells were measured by 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry, transwell invasion assay and Western blot assay, respectively. The binding sites between let-7a-5p and circ-ABCB10 or DUSP7 were predicted by Starbase bioinformatic software, and the combination was confirmed by dual-luciferase reporter assay. The protein expression of DUSP7 was examined by Western blot assay. Murine xenograft model was established to confirm the role of circ-ABCB10 in vivo. Results: Circ-ABCB10 depletion promoted the PTX sensitivity and apoptosis while suppressed the invasion and autophagy of PTX-resistant BC cells. Circ-ABCB10 could bind to let-7a-5p in BC cells, and circ-ABCB10 contributed to PTX resistance of BC cells via let-7a-5p. DUSP7 is a direct target of let-7a-5p in BC cells, and the accumulation of DUSP7 reversed the promoting effects of let-7a-5p overexpression on the PTX sensitivity and apoptosis and the inhibitory impact on the invasion and autophagy of PTX-resistant BC cells. Circ-ABCB10 interference suppressed the growth of BC tumors in vivo. Conclusion: Circ-ABCB10 mediated PTX resistance, apoptosis, invasion and autophagy of BC cells via let-7a-5p/DUSP7 axis.

mentioning

confidence: 99%

<p>Circ-ABCB10 Contributes to Paclitaxel Resistance in Breast Cancer Through Let-7a-5p/DUSP7 Axis</p>

Gong

et al. 2020

CMAR

Molecular Therapy - Oncolytics

“…As the most critical component of non-small-cell lung cancer, lung adenocarcinoma has been widely investigated in most recent years; however, there have been no effective treatment strategies. For most of the current studies concerning the etiology of lung adenocarcinoma, the A549 cell line provides an excellent model for the investigation of lung cancer and, therefore, is widely used 32, 33, 34. In this study, we demonstrated that the suppression of BCL-xL by let-7a-5p enhanced autophagy but repressed migration and invasion in A549 lung cancer cells, which was tightly associated with the activation of the PI3K-signaling pathway.…”

Section: Discussionmentioning

confidence: 65%

Crosstalk between let-7a-5p and BCL-xL in the Initiation of Toxic Autophagy in Lung Cancer

Duan

Tian

et al. 2019

Self Cite

Autophagy is essential for cellular metabolism and plays pivotal roles in carcinogenesis, while excessive autophagy induces toxicity and cell death. Our previous studies have suggested that let-7a-5p/BCL-xL might regulate autophagy in lung cancer, but the regulatory mechanism is unclear. The central goal of the study was to figure out the role of let-7a-5p/BCL-xL in the initiation of autophagy and its effect on the migration, invasion, and proliferation of A549 cells as well as its therapeutic potential in lung cancer. Based on the genome-wide expression profiles of lung cancer, BCL-xL and let-7a-5p were found to be dysregulated and negatively correlated in lung adenocarcinoma, which was associated with the survival of lung cancer. The crosstalk between BCL-xL and let-7a-5p was then investigated using dual-luciferase reporter assay, and it was found to suppress the migration and invasion of A549 cells. Further, we found that the crosstalk between BCL-xL and let-7a-5p could lead to toxic autophagy and cell death through activating the PI3K-signaling pathway, which was independent of apoptosis or pyroptosis. These findings indicate that let-7a-5p is a sensitive initiator for toxic autophagy in A549 lung cancer cells and is an appealing target for lung cancer therapy.

“…Consistently, ectopic expression of miR-24-3p suppressed the cell migration, invasion, and proliferation of MCF7, Hep3B, B16F10, SK-Hep1, and PC-3 cells by directly targeting p130Cas(42). Moreover, let-7a-5p inhibited BCL2L1 expression and suppressed lung cancer cell proliferation, migration, and invasion(43). LncRNA NEAT1 promotes colorectal cancer cell proliferation and migration via regulating glial cell-derived neurotrophic factor by sponging miR-196a-5p(44).…”

mentioning

confidence: 67%

Identification of mRNA-miRNA-lncRNA Competing Endogenous RNA Network in Adrenocortical Carcinoma Using Bioinformatics Analysis 

Ye¹,

Wang²,

Li³

et al. 2020

Preprint

Background: Adrenocortical carcinoma (ACC) is a rare malignant tumor originating from the adrenal cortex. However, there are no eﬀective therapies to treat patients with ACC. LncRNA participates in a variety of biological processes of cancers. We constructed ceRNA network and identify key competing endogenous RNAs (ceRNAs) in adrenocortical carcinoma (ACC) using bioinformatic processing tools. Methods: Firstly, the differentially expressed genes (DEGs) were identified by analyzing GSE12368 and GSE19750 datasets. SangerBox was used to generate volcano maps. DAVID database was used for functional enrichment analysis. STRING database was used to conduct Protein-protein interaction (PPI) network, and hub genes were identified by Cytoscape plug-in CytoHubba. UCSC database was used to construct hierarchical clustering of hub genes. Upstream miRNAs of mRNAs were predicted by miRTarBase and upstream lncRNAs of miRNA by miRNet. Expression analysis for lncRNAs were performed via GEPIA. Prognostic analysis for genes, miRNAs and lncRNAs were performed via cBioPortal, OncomiR and GEPIA, respectively. Results: In this study, 49 and 276 upregulated and downregulated significant DEGs were identified. KEGG pathway enrichment analysis showed that they were significantly enriched in cancer-associated pathways. According to node degree, the top 10 upregulated genes and downregulated genes were classfied as hub genes. However, only 9 hub genes were defined as key genes because alteration was significantly associated with worse prognosis and all the 9 key genes were upregulated hub genes. Then, 15 miRNAs were predicted to target the 7 out of 9 key genes. But only 4 miRNAs were defined as key miRNAs because alteration significantly influenced prognosis in cancer. 185 lncRNAs were predicted to potentially interaction with the 4 miRNAs. Only 3 lncRNAs(XIST, HOXA11-AS and TMPO-AS1) were up-regulated and only 1 lncRNA (HOXA11-AS ) indicated alteration was significantly associated with worse prognosis in adrenocortical carcinoma. HOXA11-AS were finally identified as key lncRNA. Finally, RRM2-miR-24-3p/let-7a-5p-HOXA11-AS, CDK1/MCM4-miR-24-3P-HOXA11-AS competing endogenous RNA (ceRNA) sub-networks were constructed in adrenocortical carcinoma. Conclution：This study has constructed RRM2-miR-24-3p/let-7a-5p-HOXA11-AS, CDK1/MCM4-miR-24-3p-HOXA11-AS competing endogenous RNA (ceRNA) sub-networks. Our results suggested that these sub-networks might be potential therapeutic targets or prognostic biomarkers in ACC.