The N-terminal polypeptide derived from vMIP-II exerts its anti-tumor activity in human breast cancer by regulating lncRNA SPRY4-IT1

Metformin and long non-coding RNAs in breast cancer

Breast cancer (BC) is the second most common cancer and cause of death in women. In recent years many studies investigated the association of long non-coding RNAs (lncRNAs), as novel genetic factors, on BC risk, survival, clinical and pathological features. Recent studies also investigated the roles of metformin treatment as the firstline treatment for type 2 diabetes (T2D) played in lncRNAs expression/regulation or BC incidence, outcome, mortality and survival, separately. This comprehensive study aimed to review lncRNAs associated with BC features and identify metformin-regulated lncRNAs and their mechanisms of action on BC or other types of cancers. Finally, metformin affects BC by regulating five BC-associated lncRNAs including GAS5, HOTAIR, MALAT1, and H19, by several molecular mechanisms have been described in this review. In addition, metformin action on other types of cancers by regulating ten lncRNAs including AC006160.1, Loc100506691, lncRNA-AF085935, SNHG7, HULC, UCA1, H19, MALAT1, AFAP1-AS1, AC026904.1 is described.

A Review on the Role of SPRY4-IT1 in the Carcinogenesis

Sprouty RTK signaling antagonist 4-intronic transcript 1 (SPRY4-IT1) is a long non-coding RNA (lncRNA) encoded by a gene located on 5q31.3. This lncRNA has a possible role in the regulation of cell growth, proliferation, and apoptosis. Moreover, since SPRY4-IT1 controls levels of lipin 2, it is also involved in the biosynthesis of lipids. During the process of biogenesis, SPRY4-IT1 is produced as a primary transcript which is then cleaved to generate a mature transcript which is localized in the cytoplasm. SPRY4-IT1 has oncogenic roles in diverse tissues. A possible route of participation of SPRY4-IT1 in the carcinogenesis is through sequestering miRNAs such as miR-101-3p, miR-6882-3p and miR-22-3p. The sponging effect of SPRY4-IT1 on miR-101 has been verified in colorectal cancer, osteosarcoma, cervical cancer, bladder cancer, gastric cancer and cholangiocarcinoma. SPRY4-IT1 has functional interactions with HIF-1α, NF-κB/p65, AMPK, ZEB1, MAPK and PI3K/Akt signaling. We explain the role of SPRY4-IT1 in the carcinogenesis according to evidence obtained from cell lines, xenograft models and clinical studies.

Long Non-Coding RNAs as Potential Diagnostic and Prognostic Biomarkers in Breast Cancer: Progress and Prospects

Breast cancer is the most common malignancy among women worldwide, excluding non-melanoma skin cancer. It is now well understood that breast cancer is a heterogeneous entity that exhibits distinctive histological and biological features, treatment responses and prognostic patterns. Therefore, the identification of novel ideal diagnostic and prognostic biomarkers is of utmost importance. Long non-coding RNAs (lncRNAs) are commonly defined as transcripts longer than 200 nucleotides that lack coding potential. Extensive research has shown that lncRNAs are involved in multiple human cancers, including breast cancer. LncRNAs with dysregulated expression can act as oncogenes or tumor-suppressor genes to regulate malignant transformation processes, such as proliferation, invasion, migration and drug resistance. Intriguingly, the expression profiles of lncRNAs tend to be highly cell-type-specific, tissue-specific, disease-specific or developmental stage-specific, which makes them suitable biomarkers for breast cancer diagnosis and prognosis.

Spindle and kinetochore-associated protein 2 facilitates the proliferation and invasion of hepatocellular carcinoma via the regulation of Wnt/β-catenin signaling

Recent studies have shown that spindle and kinetochore-associated protein 2 (SKA2) is dysregulated in multiple tumors and acts as a key regulator of tumor progression. However, whether SKA2 plays a role in hepatocellular carcinoma (HCC) has not been fully elucidated. The purpose of this study was to explore the expression, function and underlying molecular mechanism of SKA2 in HCC. We found that SKA2 was highly expressed in HCC tissues and cell lines. Knockdown of SKA2 caused marked reductions in the proliferative, colony-forming and invasive capacities of HCC cells, while SKA2 overexpression had opposite effects. Further experiments revealed that overexpression of SKA2 enhanced expression levels of phosphorylated glycogen synthase kinase-3β (GSK-3β) and active β-catenin in HCC cells. Moreover, SKA3 overexpression enhanced transcriptional activity mediated by Wnt/β-catenin signaling. Knockdown of SKA3 downregulated the activation of Wnt/β-catenin signaling, and the effect was significantly reversed by the inhibition of GSK-3β. Notably, inhibition of Wnt/β-catenin signaling markedly abrogated SKA2-mediated promotion effect on HCC proliferation and invasion. In addition, knockdown of SKA2 impeded tumor formation and growth in HCC cells in a nude mouse in vivo model. Overall, these findings indicate that SKA2 accelerates the progression of HCC through the upregulation of Wnt/β-catenin signaling. Our study highlights a potential role of SKA2 in HCC progression and suggests it as a possible target for HCC treatment.

Inferring LncRNA-disease associations based on graph autoencoder matrix completion

Accumulating studies have indicated that long non-coding RNAs (lncRNAs) play crucial roles in large amount of biological processes. Predicting lncRNA-disease associations can help biologist to understand the molecular mechanism of human disease and benefit for disease diagnosis, treatment and prevention. In this paper, we introduce a computational framework based on graph autoencoder matrix completion (GAMCLDA) to identify lncRNA-disease associations. In our method, the graph convolutional network is utilized to encode local graph structure and features of nodes for learning latent factor vectors of lncRNA and disease. Further, the inner product of lncRNA factor vector and disease factor vector is used as decoder to reconstruct the lncRNA-disease association matrix. In addition, the cost-sensitive neural network is utilized to deal with the imbalance between positive and negative samples. The experimental results show GAMLDA outperforms other state-of-the-art methods in prediction performance which is evaluated by AUC value, AUPR value, PPV and F1-score. Moreover, the case study shows our method is the effectively tool for potential lncRNA-disease prediction.

LncRNA SPRY4-IT1 regulates breast cancer cell stemness through competitively binding miR-6882-3p with TCF7L2

SPRY4-intronic transcript 1 has been found in several kinds of cancers, but the role of SPRY4-IT1 in breast cancer stem cells has not been studied. We investigated whether SPRY4-IT1 is involved in the promotion of breast cancer stem cells (BCSCs). We used qRT-PCR to detect the expression of SPRY4-IT1 in MCF-7 cells and MCF-7 cancer stem cells (MCF-7 CSCs). The effects of SPRY4-IT1 on the proliferation and renewal ability of breast cancer cells were investigated by in vitro and in vivo assays (ie in situ hybridization, colony formation assay, sphere formation assay, flow cytometry assay, western blotting, xenograft model and immunohistochemistry). The mechanism of SPPRY4-IT1 as a ceRNA was studied by a dual-luciferase reporter assay and bioinformatic analysis. In our study, SPRY4-IT1 was up-regulated in MCF-7 CSCs compared with MCF-7 cells, and high SPRY4-IT1 expression was related to reduced breast cancer patient survival. Furthermore, SPRY4-IT1 overexpression promoted breast cancer cell proliferation and stemness in vitro and in vivo. In addition, SPRY4-IT1 knockdown suppressed BCSC renewal ability and stemness maintenance in vivo and in vitro. The dual-luciferase reporter assays indicated that SPRY4-IT1 as a sponge for miR-6882-3p repressed transcription factor 7-like 2 (TCF7L2) expression. Taken together, these findings demonstrated that SPRY4-IT1 promotes proliferation and stemness of breast cancer cells as well as renewal ability and stemness maintenance of BCSCs by increasing the expression of TCF7L2 through targeting miR-6882-3p.

Upregulation of microRNA-520a-3p inhibits the proliferation, migration and invasion via spindle and kinetochore associated 2 in gastric cancer

MicroRNAs (miR) serve important roles in the development and progression of tumors by targeting different genes. miR-520a-3p reported in lung and breast cancers as a tumor suppressor gene. However, the expression and functional significance of miR-520a-3p is not completely understood in gastric cancer (GC). In the present study, it was demonstrated that the expression levels of miR-520a-3p were significantly downregulated in GC tissues and cells using RT-qPCR. In addition, downregulated expression of miR-520a-3p was associated with the clinical stage of the tumor and invasion in patients with GC. Furthermore, overexpression of miR-520a-3p significantly inhibited cell proliferation, invasion and migration in SGC-7901 and MGC-803 GC cell lines using proliferation, wound healing and cell invasion assays. Spindle and kinetochore associated 2 (SKA2) was upregulated in GC cells using western blot analysis and a target gene of miR-520a-3p; miR-520a-3p mimics significantly reduced SKA2 expression. In addition, upregulation of SKA2 protein expression SKA2 reversed the miR-520a-3p-mediated inhibition of SGC-7901 cell proliferation, migration and invasion. In conclusion, miR-520a-3p functioned as a tumor suppressor gene by targeting SKA2 in GC cell lines, and may serve as a novel prognostic and potential therapeutic marker.