Chitosan inhibits vascular intimal hyperplasia via LINC01615/MIR-185-5p/PIK3R2 signaling pathway

The abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) are the main pathological processes which are involved in the formation of new intima. In our previous study, we found that chitosan can inhibit the formation of new intima in the arteriovenous fistulas of uremic patients, and the expression of LINC01615 was significantly increased in patients after treatment with chitosan. Therefore, this study aims to further explore the effect of chitosan on the intimal hyperplasia and elucidate the potential molecular mechanism. In vitro, we found that in chitosan-treated VSMC, the levels of Il-1β, IL-6 and TNF-α decreased, and the intimal hyperplasia was inhibited along with significantly downregulated PIK3R2 and upregualted PI3K, AKT and p-AKT. Meanwhile, we observed the phenotypic transformation of hVSMCs after LINC01615 was upregulated. In addition, inflammatory factors showed the same changes in the process of up-regulating LINC01615. Moreover, only in the LINC01615 overexpression and miR-185-5p mimic experimental group, the inhibition of intimal hyperplasia was the most obvious. The interaction between LINC01615 and miR-185-5p, miR-185-5p and PIK3R2 was further confirmed by the dual luciferase assay. These results suggest that chitosan has a potential preventive effect on neointimal hyperplasia and related vascular remodeling.

LINC01615 maintains cell survival in adaptation to nutrient starvation through the pentose phosphate pathway and modulates chemosensitivity in colorectal cancer

Numerous mechanisms involved in promoting cancer cell survival under nutrient starvation have been described. Long noncoding RNAs (lncRNAs) have emerged as critical players in colorectal cancer (CRC) progression, but the role of lncRNAs in the progression of CRC under nutrient starvation has not been well clarified. Here, we identified a lncRNA, LINC01615, that was significantly upregulated in response to serum starvation. LINC01615 can contribute to the adaptation of CRC cells to serum-deprived conditions and enhance cell survival under similar conditions. LINC01615 activated the pentose phosphate pathway (PPP) under serum starvation, manifested as decreased ROS production and enhanced nucleotide and lipid synthesis. Glucose-6-phosphate dehydrogenase (G6PD) is a key rate-limiting enzyme of the PPP, and LINC01615 promoted G6PD expression by competitively binding with hnRNPA1 and facilitating G6PD pre-mRNA splicing. Moreover, we also found that serum starvation led to METTL3 degradation by inducing autophagy, which further increased the stability and level of LINC01615 in a m6A-dependent manner. LINC01615 knockdown combined with oxaliplatin achieved remarkable antitumor effects in PDO and PDX models. Collectively, our results demonstrated a novel adaptive survival mechanism permitting tumor cells to survive under limiting nutrient supplies and provided a potential therapeutic target for CRC.

SIPA1 Regulates LINC01615 to Promote Metastasis in Triple-Negative Breast Cancer

Simple Summary

Breast cancer is a malignant tumor that often endangers women. After undergoing surgery and supplementary chemotherapy, however, tumor recurrence has not been well researched. The primary cause is high metastatic rates. Hence, bioinformatic and functional analyses were performed to indicate the effect of LINC01615 on breast cancer. We revealed that LINC01615 is regulated by the transcription factor SIPA1 in promoting breast cancer cell malignancy.

Abstract

Long non-coding RNAs (lncRNAs) are reported to play an important regulatory effect in carcinogenesis and malignancy. We found by high-throughput sequencing that LINC01615 is upregulated in breast cancer patients and reduces patients’ overall survival. In vivo and in vitro experiments, we clarified that overexpression of LINC01615 can promote breast cancer cell metastasis ability. The expression of LINC01615 is regulated by the transcriptional activator SIPA1, thereby promoting carcinogenesis in breast cancer cells. Our research clarified that LINC01615 can act as an oncogenic factor in promoting the development of breast cancer.

Establishment and Validation of a Ferroptosis-Related Long Non-Coding RNA Signature for Predicting the Prognosis of Stomach Adenocarcinoma

Background: Ferroptosis is a form of regulated cell death that follows cell membrane damage and mostly depends on iron-mediated oxidative. Long non-coding RNAs (LncRNAs) are associated with the development of a variety of tumors. Till date, LncRNAs have been reported to intervene in ferroptosis. Therefore, we intended to provide a prognostic ferroptosis-related-lncRNA signature in stomach adenocarcinoma (STAD).

Methods: We downloaded ferroptosis-related genes from the FerrDb database and RNA sequencing data and clinicopathological characteristics from The Cancer Genome Atlas. Gene differential expression analysis was performed using the “limma” package. We used Cox regression analysis to determine the ferroptosis-related lncRNAs signature with the lowest AIC value. The Kaplan–Meier curve, ROC curve, and nomogram were used to evaluate the prognostic value of the risk score. Gene set enrichment analysis (GSEA) was used to explore the biologic functions of the three ferroptosis-related lncRNAs. LINC01615 expression in gastric cancer cell lines and tissues was measured by real-time PCR. A nuclear-cytoplasmic fractionation assay was used to analyze the subcellular localization for LINC01615. Furthermore, we used bioinformatics to predict potential target microRNAs (miRNAs) of LINC01615 and their target ferroptosis-related mRNAs.

Results: Three ferroptosis-related-lncRNA signatures (AP000695.2, AL365181.3, and LINC01615) were identified, and then Kaplan–Meier, Cox regression analyses, and ROC curve confirmed that the ferroptosis-related-lncRNA model could predict the prognosis of STAD. The GSEA indicated that the three ferroptosis-related lncRNAs might be related to the extracellular matrix and cellular activities. LINC01615 is highly expressed in gastric cancer cell lines and tissues. A nuclear-cytoplasmic fractionation assay confirmed that in gastric cancer cell lines, most LINC01615 was enriched in the cytoplasm. Bioinformatics further predicts four potential target miRNAs of LINC01615 and then figured out 26 target ferroptosis-related mRNAs.

Conclusion: We established a three-ferroptosis-related-lncRNA model (AP000695.2, AL365181.3, and LINC01615) that can predict the prognosis of STAD patients. We also expected to provide a promising target for LINC01615 for research in the future, which was highly expressed in gastric cancer and cell lines and acted as a ceRNA to get involved in ferroptosis.

Identification of LINC01615 as potential metastasis-related long noncoding RNA in hepatocellular carcinoma

Hepatocellular carcinoma is one of the most prevalent and fatal cancers. Studying the long noncoding RNA (lncRNA) alterations in hepatocellular carcinoma may lead to new therapeutic strategies. We checked whether there were correlations between The Cancer Genome Atlas expression profiles of the differentially expressed lncRNAs and their DNA methylation status or the copy number variations for hepatocellular carcinoma. We obtained 41 lncRNAs that were differentially expressed between tumor and normal samples, and their DNA methylation status was negatively correlated with the expression levels. We identified five lncRNAs that were recurrently amplified or deleted in tumor samples, but none of them were associated with the messenger RNA (mRNA) expression levels. To obtain the biological function of these lncRNAs, the coexpressed mRNAs in the hepatocellular carcinoma were figured out. A total of 10 lncRNAs were highly correlated with at least one gene. Six out of the ten lncRNAs were already known to be related with cancer previously. LINC01615 had 72 coexpressed genes, and we carried out the gene ontology (GO) term enrichment for these protein-coding genes. The results suggested that these lncRNAs were associated with extracellular matrix organization. To summarize, we identified 41 potentially cancer-related lncRNAs. In particular, we proposed that LINC01615 potentially affected the extracellular matrix and had further impacts on the metastasis of hepatocellular carcinoma.