Long noncoding RNA LINC00284 facilitates cell proliferation in papillary thyroid cancer via impairing miR-3127-5p targeted E2F7 suppression

The crosstalk between non-coding RNAs and cell-cycle events: A new frontier in cancer therapy

The cell cycle comprises sequential events during which a cell duplicates its genome and divides it into two daughter cells. This process is tightly regulated to ensure that the daughter cell receives identical copied chromosomal DNA and that any errors in the DNA during replication are correctly repaired. Cyclins and their enzyme partners, cyclin-dependent kinases (CDKs), are critical regulators of G- to M-phase transitions during the cell cycle. Mitogenic signals induce the formation of the cyclin/CDK complexes, resulting in phosphorylation and activation of the CDKs. Once activated, cyclin/CDK complexes phosphorylate specific substrates that drive the cell cycle forward. The sequential activation and inactivation of cyclin-CDK complexes are tightly controlled by activating and inactivating phosphorylation events induced by cell-cycle proteins. The non-coding RNAs (ncRNAs), which do not code for proteins, regulate cell-cycle proteins at the transcriptional and translational levels, thereby controlling their expression at different cell-cycle phases. Deregulation of ncRNAs can cause abnormal expression patterns of cell-cycle-regulating proteins, resulting in abnormalities in cell-cycle regulation and cancer development. This review explores how ncRNA dysregulation can disrupt cell division balance and discusses potential therapeutic approaches targeting these ncRNAs to control cell-cycle events in cancer treatment.

ALDH1A3 promotes invasion and metastasis in triple-negative breast cancer by regulating the plasminogen activation pathway

Aldehyde dehydrogenase 1A3 (ALDH1A3) is a cancer stem cell marker that promotes metastasis. Triple-negative breast cancer (TNBC) progression has been linked to ALDH1A3-induced gene expression changes. To investigate the mechanism of ALDH1A3-mediated breast cancer metastasis, we assessed the effect of ALDH1A3 on the expression of proteases and the regulators of proteases that degrade the extracellular matrix, a process that is essential for invasion and metastasis. This revealed that ALDH1A3 regulates the plasminogen activation pathway; it increased the levels and activity of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA). This resulted in a corresponding increase in the activity of serine protease plasmin, the enzymatic product of tPA and uPA. The ALDH1A3 product all-trans-retinoic acid similarly increased tPA and plasmin activity. The increased invasion of TNBC cells by ALDH1A3 was plasminogen-dependent. In patient tumours, ALDH1A3 and tPA are co-expressed and their combined expression correlated with the TNBC subtype, high tumour grade and recurrent metastatic disease. Knockdown of tPA in TNBC cells inhibited plasmin generation and lymph node metastasis. These results identify the ALDH1A3-tPA-plasmin axis as a key contributor to breast cancer progression.

A Novel Paclitaxel Derivative for Triple-Negative Breast Cancer Chemotherapy

Paclitaxel-triethylenetetramine hexaacetic acid conjugate (PTX-TTHA), a novel semi-synthetic taxane, is designed to improve the water solubility and cosolvent toxicity of paclitaxel in several aminopolycarboxylic acid groups. In this study, the in vitro and in vivo antitumor effects and mechanisms of PTX-TTHA against triple-negative breast cancer (TNBC) and its intravenous toxicity were evaluated. Results showed the water solubility of PTX-TTHA was greater than 5 mg/mL, which was about 7140-fold higher than that of paclitaxel (<0.7 µg/mL). PTX-TTHA (10-10⁵ nmol/L) could significantly inhibit breast cancer proliferation and induce apoptosis by stabilizing microtubules and arresting the cell cycle in the G2/M phase in vitro, with its therapeutic effect and mechanism similar to paclitaxel. However, when the MDA-MB-231 cell-derived xenograft (CDX) tumor model received PTX-TTHA (13.73 mg/kg) treatment once every 3 days for 21 days, the tumor inhibition rate was up to 77.32%. Furthermore, PTX-TTHA could inhibit tumor proliferation by downregulating Ki-67, and induce apoptosis by increasing pro-apoptotic proteins (Bax, cleaved caspase-3) and TdT-mediated dUTP nick end labeling (TUNEL) positive apoptotic cells, and reducing anti-apoptotic protein (Bcl-2). Moreover, PTX-TTHA demonstrated no sign of acute toxicity on vital organs, hematological, and biochemical parameters at the limit dose (138.6 mg/kg, i.v.). Our study indicated that PTX-TTHA showed better water solubility than paclitaxel, as well as comparable in vitro and in vivo antitumor activity in TNBC models. In addition, the antitumor mechanism of PTX-TTHA was related to microtubule regulation and apoptosis signaling pathway activation.

Overexpression of ST7-AS1 Enhances Apoptosis and Inhibits Proliferation of Papillary Thyroid Carcinoma Cells Via microRNA-181b-5p-Dependent Inhibition Tripartite Motif Containing 3

Long non-coding RNAs (lncRNAs) are of great significance in the pathogenesis and progression of papillary thyroid carcinoma (PTC). LncRNA tumorigenicity 7 antisense RNA 1 (ST7-AS1) is a newly identified lncRNA serving as an oncogene or tumor suppressor in different tumors; however, the role of ST7-AS1 in PTC remains completely unknown. In this study, ST7-AS1 was mainly distributed in the cytoplasm of PTC cells and presented reduced expression in THCA tumors and PTC cell lines. Functional experiments revealed that overexpressed ST7-AS1 inhibited the viability and proliferation of PTC cells, whereas accelerated the apoptosis of PTC cells. The expression of miR-181b-5p was upregulated and it bound with ST7-AS1 in PTC cells. Moreover, TRIM3 exhibited downregulated expression level in PTC cells and ST7-AS1 elevated TRIM3 expression via harboring miR-181b-5p. Rescue experiments illuminated that knockdown of TRIM3 reversed ST7-AS1 overexpression-induced promotion on PTC cell proliferation and suppression on PTC cell apoptosis. Overall, overexpression of ST7-AS1 enhances apoptosis and represses proliferation of PTC cells via targeting the miR-181b-5p/TRIM3 axis, which may help broaden the horizon and establish the foundation to develop therapeutic strategies for PTC in the future.

Adding pieces to the puzzle of differentiated-to-anaplastic thyroid cancer evolution: the oncogene E2F7

Anaplastic Thyroid Cancer (ATC) is the most aggressive and de-differentiated subtype of thyroid cancer. Many studies hypothesized that ATC derives from Differentiated Thyroid Carcinoma (DTC) through a de-differentiation process triggered by specific molecular events still largely unknown. E2F7 is an atypical member of the E2F family. Known as cell cycle inhibitor and keeper of genomic stability, in specific contexts its function is oncogenic, guiding cancer progression. We performed a meta-analysis on 279 gene expression profiles, from 8 Gene Expression Omnibus patient samples datasets, to explore the causal relationship between DTC and ATC. We defined 3 specific gene signatures describing the evolution from normal thyroid tissue to DTC and ATC and validated them in a cohort of human surgically resected ATCs collected in our Institution. We identified E2F7 as a key player in the DTC-ATC transition and showed in vitro that its down-regulation reduced ATC cells' aggressiveness features. RNA-seq and ChIP-seq profiling allowed the identification of the E2F7 specific gene program, which is mainly related to cell cycle progression and DNA repair ability. Overall, this study identified a signature describing DTC de-differentiation toward ATC subtype and unveiled an E2F7-dependent transcriptional program supporting this process.

The Expanding Role of Cancer Stem Cell Marker ALDH1A3 in Cancer and Beyond

Aldehyde dehydrogenase 1A3 (ALDH1A3) is one of 19 ALDH enzymes expressed in humans, and it is critical in the production of hormone receptor ligand retinoic acid (RA). We review the role of ALDH1A3 in normal physiology, its identification as a cancer stem cell marker, and its modes of action in cancer and other diseases. ALDH1A3 is often over-expressed in cancer and promotes tumor growth, metastasis, and chemoresistance by altering gene expression, cell signaling pathways, and glycometabolism. The increased levels of ALDH1A3 in cancer occur due to genetic amplification, epigenetic modifications, post-transcriptional regulation, and post-translational modification. Finally, we review the potential of targeting ALDH1A3, with both general ALDH inhibitors and small molecules specifically designed to inhibit ALDH1A3 activity.

Role of Long Intergenic Noncoding RNAs in Cancers with an Overview of MicroRNA Binding

Long intergenic noncoding RNAs are transcripts originating from the regions without annotated coding genes. They are located mainly in the nucleus and regulate gene expression. Long intergenic noncoding RNAs can be also found in the cytoplasm acting as molecular sponges of certain microRNAs. This is crucial in various biological and signaling pathways. Expression levels of many long intergenic noncoding RNAs are disease related. In this article, we focus on the long intergenic noncoding RNAs and their relation to different types of cancer. Studies showed that abnormal expression of long intergenic noncoding RNA deregulates signaling pathways due to the disrupted free microRNA pool. Hampered signaling pathways leads to abnormal cell proliferation and restricts cell death, thus resulting in oncogenesis. This review highlights promising therapeutic targets and enables the identification of potential biomarkers specific for a certain type of cancer. Moreover, we provide an outline of long intergenic noncoding RNAs/microRNA axes, which might be applied in further detailed experiments broadening our knowledge about the cellular role of those RNA species.

ALDH1A3–Linc00284 Axis Mediates the Invasion of Colorectal Cancer by Targeting TGFβ Signaling via Sponging miR-361-5p

ALDH1A3 and Linc00284 involve in colorectal cancer (CRC) development; however, the regulatory mechanism is still unclear. In this study, we collected clinicopathological characteristics and tissue samples from 73 CRC patients to analyze the expression of ALDH1A3, Linc00284, TGFβ signaling and miR-361-5p using qPCR, Western blotting, and ELISA. Multiple CRC cell lines were evaluated in this study, and the highest level of ALDH1A3 was observed in SW480 cells. To investigate the regulatory mechanism, RIP and luciferase assays were used to validate the interaction between Linc00284, miR-361-5p, and TGFβ. Proliferation, viability, migration, and invasion assays were performed to profile the effects of the ALDH1A3–Linc00284 axis in CRC cell functions, which was upregulated in CRC tissues. Knockdown ALDH1A3 or Linc00284 significantly reduced TGFβ expression and suppressed the EMT process, while overexpression had opposite effects. miR-361-5p targeted TGFβ directly, which negatively correlated with ALDH1A3–Linc00284 expression and CRC progression. Mechanistically, upregulation of ALDH1A3–Linc00284 promotes colorectal cancer invasion and migration by regulating miR-361-5p/TGFβ signaling pathway. Dysregulation of the ALDH1A3–Linc00284-miR-361-5p-TGFβ axis causes CRC invasion, which might provide a new insight into the treatment of CRC.

Development of an Inflammation-Related lncRNA-miRNA-mRNA Network Based on Competing Endogenous RNA in Breast Cancer at Single-Cell Resolution

The role and mechanism of inflammation in breast cancer is unclear. This study aims to probe the relationship between inflammation and long non-coding RNAs (lncRNAs) and to stablish an inflammation-related competing endogenous RNA (ceRNA) network in breast cancer. Inflammation-related lncRNAs and target genes were screened based on the data from four single-cell RNA sequencing (scRNA-seq) studies and miRNAs were bioinformatically predicted according to ceRNA hypothesis. A series of in silico analyses were performed to construct an inflammation-related ceRNA network in breast cancer. Consequently, a total of seven inflammation-related lncRNAs were selected, after which LRRC75A-AS1 was identified as the most potential lncRNA in view of its expression and prognostic predictive value in breast cancer. Finally, an inflammation-related ceRNA network in breast cancer at the single cell level was established based on lncRNA LRRC75A-AS1, miR-3127-5p, miR-2114-3p, RPL36 and RPL27A mRNAs. Collectively, the lncRNA LRRC75A-AS1 and the LRRC75A-AS1-based on ceRNA network may exert crucial roles in modulating inflammation response during the initiation and progression of breast cancer.

MicroRNA-22-3p targeted regulating transcription factor 7-like 2 (TCF7L2) constrains the Wnt/β-catenin pathway and malignant behavior in osteosarcoma

Various studies have manifested that microRNAs (miRNAs) are involved in the modulation of the occurrence and development of osteosarcoma (OS). However, whether miR-22-3p is associated with OS growth remains unclear. In the study, the potential molecular mechanisms of miR-22-3p in OS was explored. It was affirmed that miR-22-3p was associated with distant metastasis and tumor size in OS patients, and reduced in OS tissues and cells while transcription factor 7-like 2 (TCF7L2) was elevated. Elevated miR-22-3p repressed OS cell progression, and the Wnt/β-catenin pathway, while elevated TCF7L2 was opposite. MiR-22-3p targeted TCF7L2 in OS. In functional rescue experiments, knockdown of miR-22-3p on OS progression and promotion of Wnt/β-catenin were reversed by simultaneous knockdown of TCF7L2. Transplantation experiments in nude mice showed that elevated miR-22-3p repressed OS tumor growth and decreased TCF7L2, Wnt and β-catenin. Shortly, this study suggest that miR-22-3p refrains the Wnt/β-catenin pathway by targeting TCF7L2 and thereby preventing OS deterioration. MiR-22-3p/TCF7L2 axis is supposed to be a candidate molecular target for future OS treatment.

Genomic Instability-Related LncRNA Signature Predicts the Prognosis and Highlights LINC01614 Is a Tumor Microenvironment-Related Oncogenic lncRNA of Papillary Thyroid Carcinoma

Background

Genomic instability (GI) is among the top ten characteristics of malignancy. Long non-coding RNAs (lncRNAs) are promising cancer biomarkers that are reportedly involved in GI. So far, the clinical value of GI-related lncRNAs (GIlncs) in papillary thyroid cancer (PTC) has not been clarified.

Methods

Integrative analysis of lncRNA expression and somatic mutation profiles was performed to identify GIlncs. Analysis of differentially expressed lncRNAs in the group with high- and low- cumulative number of somatic mutations revealed significant GIlncs in PTC. Univariate and multivariate Cox proportional hazard regression analyses were performed to identify hub-GIlncs.

Results

A computational model based on four lncRNAs (FOXD2-AS1, LINC01614, AC073257.2, and AC005082.1) was identified as a quantitative index using an in-silicon discovery cohort. GILS score was significantly associated with poor prognosis, as validated in the TCGA dataset and further tested in our local RNA-Seq cohort. Moreover, a combination of clinical characteristics and the composite GILS-clinical prognostic nomogram demonstrates satisfactory discrimination and calibration. Furthermore, the GILS score and FOXD2-AS1, LINC01614, AC073257.2, and AC005082.1 were also associated with driver mutations and multiple clinical-pathological variables, respectively. Moreover, RNA-Seq confirmed the expression patterns of FOXD2-AS1, LINC01614, AC073257.2, and AC005082.1 in PTC and normal thyroid tissues. Biological experiments demonstrated that downregulated or overexpressed LINC01614 affect PTC cell proliferation, migration, and invasion in vitro. Activation of the stromal and immune cell infiltration was also observed in the high LINC01614 group in the PTC microenvironment.

Conclusion

In summary, we identified a signature for clinical outcome prediction in PTC comprising four lncRNAs associated with GI. A better understanding of the GI providing an alternative evaluation of the progression risk of PTC. Our study also demonstrated LINC01614 as a novel oncogenic lncRNA and verified its phenotype in PTC.