lncRNA Biomarkers of Glioblastoma Multiforme.

Long noncoding RNAs (lncRNAs) are RNA molecules of 200 nucleotides or more in length that are not translated into proteins. Their expression is tissue-specific, with the vast majority involved in the regulation of cellular processes and functions. Many human diseases, including cancer, have been shown to be associated with deregulated lncRNAs, rendering them potential therapeutic targets and biomarkers for differential diagnosis. The expression of lncRNAs in the nervous system varies in different cell types, implicated in mechanisms of neurons and glia, with effects on the development and functioning of the brain. Reports have also shown a link between changes in lncRNA molecules and the etiopathogenesis of brain neoplasia, including glioblastoma multiforme (GBM). GBM is an aggressive variant of brain cancer with an unfavourable prognosis and a median survival of 14-16 months. It is considered a brain-specific disease with the highly invasive malignant cells spreading throughout the neural tissue, impeding the complete resection, and leading to post-surgery recurrences, which are the prime cause of mortality. The early diagnosis of GBM could improve the treatment and extend survival, with the lncRNA profiling of biological fluids promising the detection of neoplastic changes at their initial stages and more effective therapeutic interventions. This review presents a systematic overview of GBM-associated deregulation of lncRNAs with a focus on lncRNA fingerprints in patients' blood.

The oncogenic role of SAMMSON lncRNA in tumorigenesis: A comprehensive review with especial focus on melanoma.

LncRNA Survival Associated Mitochondrial Melanoma Specific Oncogenic Non-coding RNA (SAMMSON) is located on human chromosome 3p13, and its expression is upregulated in several tumours, including melanoma, breast cancer, glioblastoma and liver cancer and has an oncogenic role in malignancy disorders. It has been reported that SAMMSON impacts metabolic regulation, cell proliferation, apoptosis, EMT, drug resistance, invasion and migration. Also, SAMMSON is involved in regulating several pathways such as Wnt, MAPK, PI3K, Akt, ERK and p53. SAMMSON is considered a potential diagnostic and prognostic biomarker in several types of cancer and a suitable therapeutic target. In addition, the highly expressed SAMMSON is closely associated with clinicopathological features of various cancers. SAMMSON has a significant role in regulating epigenetic processes by regulating histone protein or the status of DNA methylation. Herein for the first time, we comprehensively summarized the currently available SAMMSON, molecular regulatory pathways, and clinical significance. We believe that clarifying all the molecular aspects of this lncRNA can be a good guide for cancer studies in the future.

The Long Non-Coding RNA SAMMSON Is a Regulator of Chemosensitivity and Metabolic Orientation in MCF-7 Doxorubicin-Resistant Breast Cancer Cells.

Despite improvements in therapeutic strategies for treating breast cancers, tumor relapse and chemoresistance remain major issues in patient outcomes. Indeed, cancer cells display a metabolic plasticity allowing a quick adaptation to the tumoral microenvironment and to cellular stresses induced by chemotherapy. Recently, long non-coding RNA molecules (lncRNAs) have emerged as important regulators of cellular metabolic orientation. In the present study, we addressed the role of the long non-coding RNA molecule (lncRNA) SAMMSON on the metabolic reprogramming and chemoresistance of MCF-7 breast cancer cells resistant to doxorubicin (MCF-7dox). Our results showed an overexpression of SAMMSON in MCF-7dox compared to doxorubicin-sensitive cells (MCF-7). Silencing of SAMMSON expression by siRNA in MCF-7dox cells resulted in a metabolic rewiring with improvement of oxidative metabolism, decreased mitochondrial ROS production, increased mitochondrial replication, transcription and translation and an attenuation of chemoresistance. These results highlight the role of SAMMSON in the metabolic adaptations leading to the development of chemoresistance in breast cancer cells. Thus, targeting SAMMSON expression levels represents a promising therapeutic route to circumvent doxorubicin resistance in breast cancers.

LncRNA SAMMSON Overexpression Suppresses Vascular Smooth Muscle Cell Proliferation via Inhibiting miR-130a Maturation to Participate in Intracranial Aneurysm.

BACKGROUND: MiR-130a is a recently identified critical player in vascular smooth muscle cell (VSMC) proliferation, which participates in intracranial aneurysm (IA). However, the involvement of miR-130a in IA and its upstream regulator are unknown. Our preliminary sequencing analysis revealed a close correlation between miR-130a and lncRNA SAMMSON across IA samples. Therefore, we further studied the crosstalk between SAMMSON and miR-130a in IA. METHODS: SAMMSON and miR-130a expression were measured using RT-qPCR. SAMMSON subcellular location was analyzed with nuclear fractionation assay. Their direct interaction was explored with RNA pull-down assay. The role of SAMMSON in miR-130a maturation was studied with overexpression analysis. VSMC cell proliferation was analyzed with BrdU assay. RESULTS: SAMMSON and premature miR-130a were deregulated in IA, while mature miR-130a was upregulated in IA. SAMMSON is localized in both the nucleus and cytoplasm, and direct interaction between SAMMSON and miR-130a was observed. SAMMSON overexpression suppressed miR-130a maturation in VSMCs and reduced the enhancing effects of miR-130a on VSMC cell proliferation. CONCLUSION: SAMMSON is overexpressed in IA and suppresses VSMC proliferation via inhibiting miR-130a maturation.

LncRNA SAMMSON Knockdown Inhibits the Malignancy of Glioblastoma Cells by Inactivation of the PI3K/Akt Pathway.

Dysregulated lncRNAs are proposed to be tightly associated with the progression of various tumors including glioblastoma (GBM). LncRNA Survival Associated Mitochondrial Melanoma-Specific Oncogenic Non-Coding RNA (SAMMSON) has been reported to be an oncogenic lncRNA in several tumors. Nevertheless, the specific role and molecular mechanism of SAMMSON in GBM progression remain unknown. Expression of SAMMSON in GBM tissues and cells was detected by qRT-PCR. CCK-8 and LDH release assays were applied to evaluate cellular viability. Invasion effect was assessed by Transwell invasion assay and western blot analysis of E-cadherin and N-cadherin expression. Apoptosis was detected using flow cytometry analysis and caspase-3 activity assay. The protein levels of phosphatidylinositol-3-kinase (PI3K), phosphorylated (p)-PI3K, protein kinase B (Akt) and p-Akt were estimated by western blot. We found that SAMMSON was highly expressed in GBM tissues and cells. SAMMSON knockdown suppressed cell viability and increased LDH release in GBM cells. Moreover, SAMMSON silencing impeded the invasive ability of GBM cells by regulating epithelial-to-mesenchymal transition (EMT). Furthermore, SAMMSON downregulation increased the apoptotic rate and caspase-3 activity in GBM cells. Additionally, it was demonstrated that the PI3K/Akt pathway was inhibited following SAMMSON silencing in GBM cells. Rescue assays revealed that activation of the PI3K/Akt pathway by 740Y-P abolished SAMMSON knockdown-induced viability reduction, invasion suppression and apoptosis in GBM cells. Taken together, lncRNA SAMMSON knockdown inhibited the malignancy of GBM cells by inactivation of the PI3K/Akt pathway.

Long non-coding RNA SAMMSON as a novel potential diagnostic and prognostic biomarker for oral squamous cell carcinoma.

BACKGROUND/PURPOSE: Oral squamous cell carcinoma (OSCC) is one of the most lethal malignancies which accounts for approximately 90% of all malignant oral tumours. SAMMSON is a lncRNA located on chromosome 3p13-3p14 and is known to act as an oncogene in several malignancies. However, its expression and clinical significance in oral squamous cell carcinoma (OSCC) remain mostly unclear. In this study, we investigated the expression and clinical relevance of lncRNA SAMMSON in human OSCC. MATERIALS AND METHODS: Human OSCC cell lines (Tca8113, SCC9, SCC25, CAL27, HN12, HSU3, FADU) and a human normal oral keratinocyte cell line (HNOK) were used to detect the difference of SAMMSON expression. A total of 90 OSCC patients confirmed by pathological and clinical diagnoses at the Hospital of Stomatology, Department of Periodontology, Shandong University were enrolled. The mRNA expression level was analyzed by reverse transcription PCR (QRT-PCR). Statistical analyses including Student's t-test, chi-square method, Kaplan-Meier method, Univariate and, Multivariate Cox regression analysis were performed to analyse all data. RESULTS: This study showed that the expression of SAMMSON was significantly increased in OSCC tissues and cell lines. High SAMMSON expression was significantly associated with TMN stage, tumour differentiation, lymph node metastasis distant metastasis and neighboring tissue infiltration. Patients with high expression of SAMMSON had poor overall survival and disease-free survival compared to those with low levels. Cox regression analysis showed that SAMMSON could act as an independent prognostic factor in OSCC. CONCLUSION: Serum SAMMSON expression was associated with tumour SAMMSON expression. ROC curve analysis indicated the high diagnostic sensitivity and specificity of serum SAMMSON expression in OSCC patients as compared to other traditional serum biomarker SCCA, TSGF, and CEA. These results indicated that SAMMSON might play an essential role in OSCC progression and could serve as a novel prognostic and diagnostic biomarker in OSCC.

LncRNA SAMMSON negatively regulates miR-9-3p in hepatocellular carcinoma cells and has prognostic values.

In the present study, we investigated the role of lncRNA SAMMSON in hepatocellular carcinoma (HCC). We found that SAMMSON was up-regulated in HCC tissues, and patients with high levels of SAMMSON in HCC tissues had significantly lower overall rate within 5 years after admission. miR-9-3p was down-regulated in HCC tissues and inversely correlated with SAMMSON. SAMMSON expression was not significantly affected by HBV and HCV infections in HCC patients. In HCC cells, SAMMSON overexpression resulted in down-regulated miR-9-3p expression, while miR-9-3p overexpression caused no significant changes in expression levels of SAMMSON. SAMMSON overexpression led to increased, while miR-9-3p overexpression resulted in decreased migration and invasion rates of HCC cells. Therefore, SAMMSON negatively regulated miR-9-3p in HCC cells to promote cancer cell migration and invasion.

SAMMSON drives the self-renewal of liver tumor initiating cells through EZH2-dependent Wnt/ß-catenin activation.

Liver cancer is one of the most serious cancers all over the world. Liver tumor initiating cells (TICs) account for tumor initiation and metastasis. However, the regulatory mechanism of liver TICs remains unclear. Here we found long noncoding RNA SAMMSON is highly expressed in liver cancer and liver TICs. SAMMSON silenced cells show impaired self-renewal capacity, while, its overexpression induces enhanced self-renewal. SAMMSON drives the activation of Wnt/ß-catenin signaling, and thus promotes liver TIC self-renewal. SAMMSON interacts with EZH2, a core component of PRC2 complex, and inhibits the expression of CTNNBIP1 through EZH2 dependent manner. SAMMSON binds to CTNNBIP1 promoter and recruits EZH2 to CTNNBIP1 promoter. What's more, targeting liver TICs through SAMMSON, EZH2 and Wnt/ß-catenin signaling impaired liver TIC self-renewal, decreased tumor propagation and severity. Taken together, SAMMSON drives liver TIC self-renewal through EZH2-dependent Wnt/ß-catenin activation.