miR-491-5p inhibits osteosarcoma cell proliferation by targeting PKM2

Expression and significant roles of the long non-coding RNA CASC19/miR-491-5p/HMGA2 axis in the development of gastric cancer

BACKGROUND

Gastric cancer (GC) is a common malignant tumor, long non-coding RNA and microRNA (miRNA) are important regulators that affect tumor proliferation, metastasis and chemotherapy resistance, and thus participate in tumor progression. CASC19 is a new bio-marker which can promote tumor invasion and metastasis. However, the mechanism by which CASC19 affects the progression of GC through miRNA is not clear.

AIM

To explore the role of the CASC19/miR-491-5p/HMGA2 regulatory axis in GC.

METHODS

To explore the expression and prognosis of CASC19 in GC through clinical samples, and investigate the effects of inhibiting CASC19 on the proliferation, migration, invasion and other functions of GC cells through cell counting Kit-8 (CCK-8), ethynyldeoxyuridine, Wound healing assay, Transwell, Western blot and flow cytometry experiments. The effect of miR-491-5p and HMGA2 in GC were also proved. The regulatory relationship between CASC19 and miR-491-5p, miR-491-5p and HMGA2 were validated through Dual-luciferase reporter gene assay and reverse transcription PCR. Then CCK-8, Transwell, Wound healing assay, flow cytometry and animal experiments verify the role of CASC19/miR-491-5p/HMGA2 regulatory axis.

RESULTS

The expression level of CASC19 is related to the T stage, N stage, and tumor size of patients. Knockdown of the expression of CASC19 can inhibit the ability of proliferation, migration, invasion and EMT conversion of GC cells, and knocking down the expression of CASC19 can promote the apoptosis of GC cells. Increasing the expression of miR-491-5p can inhibit the proliferation of GC cells, miR-491-5p mimics can inhibit EMT conversion, and promote the apoptosis of GC cells, while decreasing the expression of miR-491-5p can promote the proliferation and EMT conversion and inhibit the apoptosis of GC cells. The expression of HMGA2 in GC tissues is higher than that in adjacent tissues. At the same time, the expression level of HMGA2 is related to the N and T stages of the patients. Reducing the level of HMGA2 can promote cell apoptosis and inhibit the proliferation of GC cells. Cell experiments and animal experiments have proved that CASC19 can regulates the expression of HMGA2 through miR-491-5p, thereby affecting the biological functions of GC.

CONCLUSION

CASC19 regulates the expression of HMGA2 through miR-491-5p to affect the development of GC. This axis may serve as a potential biomarker and therapeutic target of GC.

Reprogramming of glucose metabolism: Metabolic alterations in the progression of osteosarcoma

Metabolic reprogramming is an adaptive response of tumour cells under hypoxia and low nutrition conditions. There is increasing evidence that glucose metabolism reprogramming can regulate the growth and metastasis of osteosarcoma (OS). Reprogramming in the progress of OS can bring opportunities for early diagnosis and treatment of OS. Previous research mainly focused on the glycolytic pathway of glucose metabolism, often neglecting the tricarboxylic acid cycle and pentose phosphate pathway. However, the tricarboxylic acid cycle and pentose phosphate pathway of glucose metabolism are also involved in the progression of OS and are closely related to this disease. The research on glucose metabolism in OS has not yet been summarized. In this review, we discuss the abnormal expression of key molecules related to glucose metabolism in OS and summarize the glucose metabolism related signaling pathways involved in the occurrence and development of OS. In addition, we discuss some of the targeted drugs that regulate glucose metabolism pathways, which can lead to effective strategies for targeted treatment of OS.

Long noncoding RNA XLOC_006786 inhibits the proliferation, invasion and metastasis of osteosarcoma cells through NOTCH3 signaling pathway by targeting miR-491-5p

Recent research has indicated that Long noncoding RNAs (LncRNAs) are crucial in many disorders, especially tumors. However, the exact role of LncRNA XLOC_006786 (LncRNA-SPIDR-2:1) in malignancies, especially in human osteosarcoma, is unclear. The results of RT‒qPCR, western blotting, CCK-8 assays, and Transwell assays showed that LncRNA XLOC_006786 inhibited osteosarcoma cell proliferation, invasion, and migration, indicating that it may be a tumor suppressor gene in osteosarcoma. We found that LncRNA XLOC_006786 negatively regulated NOTCH3, which is an oncogenic gene in osteosarcoma, as we previously reported. Bioinformatics analysis showed that miR-491-5p may be a direct target of LncRNA XLOC_006786, while NOTCH3 is a key target of miR-491-5p. Then, we verified that LncRNA XLOC_006786 could prevent lung metastatic osteosarcoma in vivo. Taken together, our research showed that LncRNA XLOC_006786 suppresses osteosarcoma proliferation, invasion, and metastasis through the NOTCH3 signaling pathway by targeting miR-491-5p.

CircMAT2B facilitates the progression of head and neck squamous cell carcinoma via sponging miR-491-5p to trigger ASCT2-mediated glutaminolysis

Circular RNAs (circRNAs) are well-known to exert significant roles in regulating the pathological processes, including human carcinogenesis. Currently, less is known about their exact roles in head and neck squamous cell carcinoma (HNSCC). Herein, we aimed to investigate and validate the role of a novel circRNA, circMAT2B, as well as its potential molecular mechanism in HNSCC progression. A cohort of 41 paired of HNSCC tumor tissues and adjacent normal tissues from HNSCC patients were collected. Further, we characterized circMAT2B expression patterns in HNSCC tissues and cell lines, as well as exploring its association with the prognosis of HNSCC patients. Biological functions on cell proliferation, apoptosis, migration, and invasion were assessed using Cell Counting Kit-8, EdU incorporation, TUNEL, wound healing, and transwell assays. Glutaminolysis was evaluated by measuring glutamine, glutamate, and α-ketoglutarate (α-KG) levels. The regulatory network of circMAT2B/miR-491-5p/ASCT2 axis was verified by RNA immunoprecipitation and luciferase reporter assays. Western blot was conducted to detect the level of ASCT2 and GLS1. Remarkably overexpressed circMAT2B was observed in HNSCC tissues and cell lines, of which high abundance was positively correlated with patients' poor prognosis. Silencing of circMAT2B inhibited cell proliferation, migration, and invasion, as well as glutaminolysis. miR-491-5p, interacted with ASCT2, was identified to be a downstream target of circMAT2B, thereby involving in circMAT2B-mediated biological effects. In summary, we draw a conclusion that circMAT2B could modulate the processes of cell proliferation, migration, invasion, and glutaminolysis of HNSCC cells partly via the miR-491-5p/ASCT2 axis by a molecular mechanism of competing endogenous RNA (ceRNA), implying an underlying circRNA-targeted therapy for HNSCC treatment.

LncRNA KCNQ1OT1 enhances the radioresistance of lung squamous cell carcinoma by targeting the miR-491-5p/TPX2-RNF2 axis

BACKGROUND

Lung cancer, especially lung squamous cell carcinoma (LUSC), is one of the most common malignant tumors worldwide. Currently, radiosensitization research is a vital direction for the improvement of LUSC therapy. Long non-coding RNAs (lncRNAs) can be novel biomarkers due to their multiple functions in cancers. However, the function and mechanism of lncRNA KCNQ1OT1 in the radioresistance of LUSC remain to be elucidated.

METHODS

The clonogenic assay was employed to determine the radioresistance of SK-MES-1R and NCI-H226R cells. Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot were conducted for the detection of gene expression. Cell proliferation was determined by the methyl thiazolyl tetrazolium (MTT) assay, colony formation assay, and 5-ethynyl-2'-deoxyuridine (EdU) staining, and cell apoptosis was assessed by flow cytometry. The relationships between genes were also evaluated by applying the luciferase reporter and radioimmunoprecipitation (RIP) assays.

RESULTS

Radioresistant LUSC cells (SK-MES-1R and NCI-H226R) had strong resistance to X-ray irradiation, and lncRNA KCNQ1OT1 was highly expressed in SK-MES-1R and NCI-H226R cells. Moreover, knockdown of lncRNA KCNQ1OT1 prominently suppressed proliferation, attenuated radioresistance, and accelerated the apoptosis of SK-MES-1R and NCI-H226R cells. More importantly, we verified that miR-491-5p was a regulatory target of lncRNA KCNQ1OT1, and Xenopus kinesin-like protein 2 (TPX2) and RING finger protein 2 (RNF2) were the target genes of miR-491-5p. The rescue experiment results also demonstrated that miR-491-5p was involved in the inhibition of cell proliferation and the downregulation of TPX2 and RNF2 expression mediated by lncRNA KCNQ1OT1 knockdown in SK-MES-1R and NCI-H226R cells.

CONCLUSIONS

LncRNA KCNQ1OT1 was associated with the radioresistance of radioresistant LUSC cells, and the lncRNA KCNQ1OT1/miR-491-5p/TPX2-RNF2 axis might be used as a therapeutic target to enhance the radiosensitivity of radioresistant LUSC cells.

The roles of glycolysis in osteosarcoma

Metabolic reprogramming is of great significance in the progression of various cancers and is critical for cancer progression, diagnosis, and treatment. Cellular metabolic pathways mainly include glycolysis, fat metabolism, glutamine decomposition, and oxidative phosphorylation. In cancer cells, reprogramming metabolic pathways is used to meet the massive energy requirement for tumorigenesis and development. Metabolisms are also altered in malignant osteosarcoma (OS) cells. Among reprogrammed metabolisms, alterations in aerobic glycolysis are key to the massive biosynthesis and energy demands of OS cells to sustain their growth and metastasis. Numerous studies have demonstrated that compared to normal cells, glycolysis in OS cells under aerobic conditions is substantially enhanced to promote malignant behaviors such as proliferation, invasion, metastasis, and drug resistance of OS. Glycolysis in OS is closely related to various oncogenes and tumor suppressor genes, and numerous signaling pathways have been reported to be involved in the regulation of glycolysis. In recent years, a vast number of inhibitors and natural products have been discovered to inhibit OS progression by targeting glycolysis-related proteins. These potential inhibitors and natural products may be ideal candidates for the treatment of osteosarcoma following hundreds of preclinical and clinical trials. In this article, we explore key pathways, glycolysis enzymes, non-coding RNAs, inhibitors, and natural products regulating aerobic glycolysis in OS cells to gain a deeper understanding of the relationship between glycolysis and the progression of OS and discover novel therapeutic approaches targeting glycolytic metabolism in OS.

Functional Screen for microRNAs Suppressing Anchorage-Independent Growth in Human Cervical Cancer Cells

The progression of anchorage-dependent epithelial cells to anchorage-independent growth represents a critical hallmark of malignant transformation. Using an in vitro model of human papillomavirus (HPV)-induced transformation, we previously showed that acquisition of anchorage-independent growth is associated with marked (epi)genetic changes, including altered expression of microRNAs. However, the laborious nature of the conventional growth method in soft agar to measure this phenotype hampers a high-throughput analysis. We developed alternative functional screening methods using 96- and 384-well ultra-low attachment plates to systematically investigate microRNAs regulating anchorage-independent growth. SiHa cervical cancer cells were transfected with a microRNA mimic library (n = 2019) and evaluated for cell viability. We identified 84 microRNAs that consistently suppressed growth in three independent experiments. Further validation in three cell lines and comparison of growth in adherent and ultra-low attachment plates yielded 40 microRNAs that specifically reduced anchorage-independent growth. In conclusion, ultra-low attachment plates are a promising alternative for soft-agar assays to study anchorage-independent growth and are suitable for high-throughput functional screening. Anchorage independence suppressing microRNAs identified through our screen were successfully validated in three cell lines. These microRNAs may provide specific biomarkers for detecting and treating HPV-induced precancerous lesions progressing to invasive cancer, the most critical stage during cervical cancer development.

Tumor Suppressive Role of miR-342-5p and miR-491-5p in Human Osteosarcoma Cells

Osteosarcomas are the most common type of malignant bone tumor. These tumors are characterized by the synthesis of an osteoid matrix. Current treatments are based on surgery and combination chemotherapy. However, for metastatic or recurrent tumors, chemotherapy is generally ineffective, and osteosarcomas are sometimes unresectable. Thus, the use of microRNAs (miRNAs) may represent an attractive alternative for the development of new therapies. Using high-throughput functional screening based on impedancemetry, we previously selected five miRNAs with potential chemosensitizing or antiproliferative effects on chondrosarcoma cells. We validated the tumor-suppressive activity of miR-491-5p and miR-342-5p in three chondrosarcoma cell lines. Here, we carried out individual functional validation of these five miRNAs in three osteosarcoma cell lines used as controls to evaluate their specificity of action on another type of bone sarcoma. The cytotoxic effects of miR-491-5p and miR-342-5p were also confirmed in osteosarcoma cells. Both miRNAs induced apoptosis. They increased Bcl-2 homologous antagonist killer (Bak) protein expression and directly targeted Bcl-2 lymphoma-extra large (Bcl-xL). MiR-342-5p also decreased B-cell lymphoma-2 (Bcl-2) protein expression, and miR-491-5p decreased that of Epidermal Growth Factor Receptor (EGFR). MiR-342-5p and miR-491-5p show tumor-suppressive activity in osteosarcomas. This study also confirms the potential of Bcl-xL as a therapeutic target in osteosarcomas.

Reduced Circulating Levels of miR-491-5p and miR-485-3p Are Associated with the Occurrence of Vertebral Fractures in Postmenopausal Women with Osteoporosis

Objective. Postmenopausal women experiences osteoporotic structural damage and bone fragility resulting from reduced bone formation and increased bone resorption. Osteoporosis frequently affects the vertebral column and causes compression fractures. This study aims to characterize roles of miRNAs in osteoporosis and subsequent incidence risk of vertebral fractures for postmenopausal women. Methods. Differentially expressed miRNAs between osteoporotic patients with vertebral fractures and osteoporotic patients without fracture were identified. This retrospective study included 78 osteoporotic patients with vertebral fractures and 82 osteoporotic patients without vertebral fractures. The plasma levels of bone metabolic markers, 25-hydroxyvitamin D (25-(OH)VitD), propeptide of type I procollagen (PINP), and β-Carboxyl terminal peptide (β-CTx), were detected using the patented electro-chemiluminescence (ECLIA) method. The expression levels of miR-491-5p and miR-485-3p were determined by qRT-PCR. Pearson correlation analysis was carried out to assess the relationship between miR-491-5p, miR-485-3p, and bone metabolic markers. Receiver operating characteristic (ROC) curves and the area under the ROC curve (AUC) were used to evaluate the performance of miR-491-5p and miR-485-3p in diagnosing the occurrence of vertebral fractures in osteoporotic patients.Results: The plasma levels of PINP and β-CTx were elevated but the plasma level of 25-(OH)VitD was declined in osteoporotic patients with vertebral fractures when comparable to those without (< 0.05). The plasma expression levels of miR-491-5p and miR-485-3p were declined osteoporotic patients with vertebral fractures when comparable to those without (< 0.001). Pearson correlation analysis revealed that the relative expression level of miR-491-5p was negatively correlated with the level of 25-(OH)VitD (r = -0.518, < 0.001) but positively correlated with the levels of PINP (r = 0.547, < 0.001) and β-CTx (r = 0.380, < 0.001). We also observed a negative correlation between the relative expression level of miR-485-3p and 25-(OH)VitD (r = -0.388, < 0.001), a positive correlation between miR-485-3p and PINP (r = 0.422,< 0.001). ROC curves for prediction of vertebral fracture following osteoporosis in postmenopausal women by miR-491-5p expression yielded 0.866 AUC and by miR-485-3p expression produced 0.848 AUC. Conclusion. The data suggest that downregulated expressions of miR-491-5p and miR-485-3p may be involved in the occurrence of vertebral fractures in postmenopausal women with osteoporosis.

The lncRNA-AK046375 Upregulates Metallothionein-2 by Sequestering miR-491-5p to Relieve the Brain Oxidative Stress Burden after Traumatic Brain Injury

We previously discovered that traumatic brain injury (TBI) induces significant perturbations in long noncoding RNA (lncRNA) levels in the mouse cerebral cortex, and lncRNA-AK046375 is one of the most significantly changed lncRNAs after TBI. lncRNA-AK046375 overexpression and knockdown models were successfully constructed both in vitro and in vivo. In cultured primary cortical neurons and astrocytes, lncRNA-AK046375 sequestered miR-491-5p, thereby enhancing the expression of metallothionein-2 (MT2), which ameliorated oxidative-induced cell injury. In addition, upregulated lncRNA-AK046375 promoted the recovery of motor, learning, and memory functions after TBI in C57BL/6 mice, and the underlying mechanism may be related to ameliorated apoptosis, inhibited oxidative stress, reduced brain edema, and relieved loss of tight junction proteins at the blood-brain barrier in the mouse brain. Therefore, we conclude that lncRNA-AK046375 enhances MT2 expression by sequestering miR-491-5p, ultimately strengthening antioxidant activity, which ameliorates neurological deficits post-TBI.

Downregulation of miR-491-5p promotes neovascularization after traumatic brain injury

MicroRNA-491-5p (miR-491-5p) plays an important role in regulating cell proliferation and migration; however, the effect of miR-491-5p on neovascularization after traumatic brain injury remains poorly understood. In this study, a controlled cortical injury model in C57BL/6 mice and an oxygen-glucose deprivation model in microvascular endothelial cells derived from mouse brain were established to simulate traumatic brain injury in vivo and in vitro, respectively. In the in vivo model, quantitative real-time-polymerase chain reaction results showed that the expression of miR-491-5p increased or decreased following the intracerebroventricular injection of an miR-491-5p agomir or antagomir, respectively, and the expression of miR-491-5p decreased slightly after traumatic brain injury. To detect the neuroprotective effects of miR-491-p, neurological severity scores, Morris water maze test, laser speckle techniques, and immunofluorescence staining were assessed, and the results revealed that miR-491-5p downregulation alleviated neurological dysfunction, promoted the recovery of regional cerebral blood flow, increased the number of lectin-stained microvessels, and increased the survival of neurons after traumatic brain injury. During the in vitro experiments, the potential mechanism of miR-491-5p on neovascularization was explored through quantitative real-time-polymerase chain reaction, which showed that miR-491-5p expression increased or decreased in brain microvascular endothelial cells after transfection with an miR-491-5p mimic or inhibitor, respectively. Dual-luciferase reporter and western blot assays verified that metallothionein-2 was a target gene for miR-491-5p. Cell counting kit 8 (CCK-8) assay, flow cytometry, and 2?,7?-dichlorofluorescein diacetate (DCFH-DA) assay results confirmed that the downregulation of miR-491-5p increased brain microvascular endothelial cell viability, reduced cell apoptosis, and alleviated oxidative stress under oxygen-glucose deprivation conditions. Cell scratch assay, Transwell assay, tube formation assay, and western blot assay results demonstrated that miR-491-5p downregulation promoted the migration, proliferation, and tube formation of brain microvascular endothelial cells through a metallothionein-2-dependent hypoxia-inducible factor-1α/vascular endothelial growth factor pathway. These findings confirmed that miR-491-5p downregulation promotes neovascularization, restores cerebral blood flow, and improves the recovery of neurological function after traumatic brain injury. The mechanism may be mediated through a metallothionein-2-dependent hypoxia-inducible factor-1α/vascular endothelial growth factor signaling pathway and the alleviation of oxidative stress. All procedures were approved by Ethics Committee of the First Affiliated Hospital of Chongqing Medical University, China (approval No. 2020-304) on June 22, 2020.

Differential Expression of Non-Coding RNA Signatures in Thyroid Cancer between Two Ethnic Groups

Filipino Americans show higher thyroid cancer recurrence rates compared to European Americans. Although they are likely to die of this malignancy, the molecular mechanism has not yet been determined. Recent studies demonstrated that small non-coding RNAs could be utilized to assess thyroid cancer prognosis in tumor models. The goal of this study is to determine whether microRNA (miRNA) signatures are differentially expressed in thyroid cancer in two different ethnic groups. We also determined whether these miRNA signatures are related to cancer staging. This is a retrospective study of archival samples from patients with thyroid cancer (both sexes) in the pathology division from the last ten years at Loma Linda University School of Medicine, California. Deidentified patient demographics were extracted from the patient chart. Discarded formalin-fixed paraffin-embedded tissues were collected post-surgeries. We determined the differential expressions of microRNA in archival samples from Filipino Americans compared to European Americans using the state-of-the-art technique, HiSeq4000. By ingenuity pathway analysis, we determined miRNA targets and the pathways that those targets are involved in. We validated their expressions by real-time quantitative PCR and correlated them with the clinicopathological status in a larger cohort of miRNA samples from both ethnicities. We identified the differentially upregulated/downregulated miRNA clusters in Filipino Americans compared to European Americans. Some of these miRNA clusters are known to target genes that are linked to cancer invasion and metastasis. In univariate analysis, ethnicity and tumor staging were significant factors predicting miR-4633-5p upregulation. When including these factors in a multivariate logistic regression model, ethnicity and tumor staging remained significant independent predictors of miRNA upregulation, whereas the interaction of ethnicity and tumor staging was not significant. In contrast, ethnicity remained an independent predictor of significantly downregulated miR-491-5p and let-7 family. We provide evidence that Filipino Americans showed differentially expressed tumor-tissue-derived microRNA clusters. The functional implications of these miRNAs are under investigation.

Deciphering the Oncogenic Role of VPS28 Modulated by miR-491-5p in Breast Cancer Cells Using In Silico and Functional Analysis

Vacuolar protein sorting–associated protein 28 (VPS28), one of the four cytosolic proteins comprising the endosomal sorting complex required for the transport I (ESCRT-I) component, has been reported to be linked to various cancers. However, less evidence is available regarding the involvement of VPS28 in breast cancer. To this end, this study focused on exploring the function of VPS28 in breast cancer cells using the in silico analysis. VPS28 expression pattern data in breast cancer tissues were collected using the Cancer Genome Atlas (TCGA) and Clinical Proteomic Tumor Analysis Consortium (CPTAC) databases and analyzed to assess the association of VPS28 with breast cancer prognosis. The elevated VPS28 expression was found in breast cancer tissues and was associated with a poor prognosis (p < 0.001). A higher VPS28 expression indicated a short survival duration (HR = 2.43; 95% CI: 1.44–4.1; p < 0.001). The CCLE database showed that VPS28 was expressed in breast cancer cell lines. The upstream targets of VPS28 were identified using the mirDIP, starBase, and TargetScan online tools. The correlation and binding relationship between miR-491-5p and VPS28 was analyzed. VPS28 or miR-491-5p gain and loss of function experiments were performed to verify their potential effect on the biological functions of breast cancer cells. Knockdown of VPS28 was shown to suppress the biological functions and enhance the apoptosis of breast cancer cell lines. Micro RNA-491-5p, identified as a posttranscriptional regulator of VPS28, was downregulated in breast cancer tissues. In contrast to the miR-491-5p inhibitor, the miR-491-5p mimic could suppress the migration, wound healing ability, and proliferation, while accelerating apoptosis. However, co-transfection of VPS28 and miR-491-5p counteracted the effect of the miR-491-5p mimic on breast cancer cell functions. Thus, our in silico analysis demonstrates that miR-491-5p can suppress breast cancer progression by attenuating the expression of VPS28.

Oxygen sensing, mitochondrial biology and experimental therapeutics for pulmonary hypertension and cancer

The homeostatic oxygen sensing system (HOSS) optimizes systemic oxygen delivery. Specialized tissues utilize a conserved mitochondrial sensor, often involving NDUFS2 in complex I of the mitochondrial electron transport chain, as a site of pO₂-responsive production of reactive oxygen species (ROS). These ROS are converted to a diffusible signaling molecule, hydrogen peroxide (H₂O₂), by superoxide dismutase (SOD2). H₂O₂ exits the mitochondria and regulates ion channels and enzymes, altering plasma membrane potential, intracellular Ca²⁺ and Ca²⁺-sensitization and controlling acute, adaptive, responses to hypoxia that involve changes in ventilation, vascular tone and neurotransmitter release. Subversion of this O₂-sensing pathway creates a pseudohypoxic state that promotes disease progression in pulmonary arterial hypertension (PAH) and cancer. Pseudohypoxia is a state in which biochemical changes, normally associated with hypoxia, occur despite normal pO₂. Epigenetic silencing of SOD2 by DNA methylation alters H₂O₂ production, activating hypoxia-inducible factor 1α, thereby disrupting mitochondrial metabolism and dynamics, accelerating cell proliferation and inhibiting apoptosis. Other epigenetic mechanisms, including dysregulation of microRNAs (miR), increase pyruvate dehydrogenase kinase and pyruvate kinase muscle isoform 2 expression in both diseases, favoring uncoupled aerobic glycolysis. This Warburg metabolic shift also accelerates cell proliferation and impairs apoptosis. Disordered mitochondrial dynamics, usually increased mitotic fission and impaired fusion, promotes disease progression in PAH and cancer. Epigenetic upregulation of dynamin-related protein 1 (Drp1) and its binding partners, MiD49 and MiD51, contributes to the pathogenesis of PAH and cancer. Finally, dysregulation of intramitochondrial Ca²⁺, resulting from impaired mitochondrial calcium uniporter complex (MCUC) function, links abnormal mitochondrial metabolism and dynamics. MiR-mediated decreases in MCUC function reduce intramitochondrial Ca²⁺, promoting Warburg metabolism, whilst increasing cytosolic Ca²⁺, promoting fission. Epigenetically disordered mitochondrial O₂-sensing, metabolism, dynamics, and Ca²⁺ homeostasis offer new therapeutic targets for PAH and cancer. Promoting glucose oxidation, restoring the fission/fusion balance, and restoring mitochondrial calcium regulation are promising experimental therapeutic strategies.

Circ_0006988 promotes the proliferation, metastasis and angiogenesis of non-small cell lung cancer cells by modulating miR-491-5p/MAP3K3 axis

Circular RNAs (circRNAs) are related to the progression of non-small cell lung cancer (NSCLC). However, the roles and mechanism of circ_0006988 are largely unknown. The levels of circ_0006988, Low-Density Lipoprotein Receptor Class A Domain Containing 3 (LDLRAD3), microRNA-491-5p (miR-491-5p), Mitogen-Activated Protein Kinase Kinase Kinase 3 (MAP3K3) were measured using quantitative real-time polymerase-chain reaction (qRT-PCR) and western blot assay. The characteristic of circ_0006988 was analyzed by RNase R assay and Actinomycin D assay. Functional analyses were processed by Cell Counting Kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay, colony formation assay, flow cytometry analysis, transwell assay, wound-healing assay and tube formation assay. The interactions between circ_0006988 and miR-491-5p as well as miR-491-5p and MAP3K3 were analyzed by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Murine xenograft model assay was processed to verify the function of circ_0006988 in vivo. Immunohistochemistry (IHC) assay was conducted to examine the level of Ki67. Circ_0006988 abundance was increased in NSCLC tissues and cells. Circ_0006988 silencing restrained NSCLC cell proliferation, migration, invasion and angiogenesis, and induced apoptosis. Circ_0006988 sponged miR-491-5p, which directly targeted MAP3K3. MiR-491-5p overexpression repressed NSCLC cell malignant behaviors. MiR-491-5p downregulation or MAP3K3 overexpression reversed the effect of circ_0006988 silencing on NSCLC cell progression. In addition, circ_0006988 knockdown reduced xenograft tumor growth. ssCirc_0006988 contributed to the development of NSCLC by miR-491-5p/MAP3K3 axis.

Tumor Suppressive Role of miR-342-5p in Human Chondrosarcoma Cells and 3D Organoids

Chondrosarcomas are malignant bone tumors. Their abundant cartilage-like extracellular matrix and their hypoxic microenvironment contribute to their resistance to chemotherapy and radiotherapy, and no effective therapy is currently available. MicroRNAs (miRNAs) may be an interesting alternative in the development of therapeutic options. Here, for the first time in chondrosarcoma cells, we carried out high-throughput functional screening using impedancemetry, and identified five miRNAs with potential antiproliferative or chemosensitive effects on SW1353 chondrosarcoma cells. The cytotoxic effects of miR-342-5p and miR-491-5p were confirmed on three chondrosarcoma cell lines, using functional validation under normoxia and hypoxia. Both miRNAs induced apoptosis and miR-342-5p also induced autophagy. Western blots and luciferase reporter assays identified for the first time Bcl-2 as a direct target of miR-342-5p, and also Bcl-xL as a direct target of both miR-342-5p and miR-491-5p in chondrosarcoma cells. MiR-491-5p also inhibited EGFR expression. Finally, only miR-342-5p induced cell death on a relevant 3D chondrosarcoma organoid model under hypoxia that mimics the in vivo microenvironment. Altogether, our results revealed the tumor suppressive activity of miR-342-5p, and to a lesser extent of miR-491-5p, on chondrosarcoma lines. Through this study, we also confirmed the potential of Bcl-2 family members as therapeutic targets in chondrosarcomas.

Long non-coding RNA VPS9D1-AS1 facilitates cell proliferation, migration and stemness in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a common cancer leading to high morbidity and mortality in worldwide. Previous studies revealed that SEC61 translocon alpha 1 subunit1 (SEC61A) can act as an oncogene in colon adenocarcinoma. However, the functions and molecular mechanism associated with HCC progression remain to be explored. This study aimed at exploring the role of SEC61A1 in HCC progression.

METHODS

EdU assay and colony formation assay were applied to assess cell proliferation. The migratory ability of transfected HCC cells was evaluated by transwell migration assay. Sphere formation assay was used to detect the stemneess of HCC cells. Bioinformatics analysis tools and mechanism experiments were used to predict and analyze the potential molecular mechanism associated with the upregulation of SEC61A1 in HCC cells.

RESULTS

Up-regulated SEC61A1 facilitated cell proliferation, migration and stemness in HCC cells. MiR-491-5p negatively regulated SEC61A1 and inhibited HCC cell proliferation and migration by targeting SEC61A1. VPS9D1 antisense RNA 1 (VPS9D1-AS1) could up-regulate SEC61A1 through sponging miR-491-5p. Early growth response 1 (EGR1) was identified as the upstream transcriptional activator for both SEC61A1 and VPS9D1-AS1.

CONCLUSIONS

Our study unveiled a novel molecular pathway facilitating HCC cell proliferation, migration and stemness, which may shed new insight into HCC treatment.

The Role of PKM2 in Metabolic Reprogramming: Insights into the Regulatory Roles of Non-Coding RNAs

Pyruvate kinase is a key regulator in glycolysis through the conversion of phosphoenolpyruvate (PEP) into pyruvate. Pyruvate kinase exists in various isoforms that can exhibit diverse biological functions and outcomes. The pyruvate kinase isoenzyme type M2 (PKM2) controls cell progression and survival through the regulation of key signaling pathways. In cancer cells, the dimer form of PKM2 predominates and plays an integral role in cancer metabolism. This predominance of the inactive dimeric form promotes the accumulation of phosphometabolites, allowing cancer cells to engage in high levels of synthetic processing to enhance their proliferative capacity. PKM2 has been recognized for its role in regulating gene expression and transcription factors critical for health and disease. This role enables PKM2 to exert profound regulatory effects that promote cancer cell metabolism, proliferation, and migration. In addition to its role in cancer, PKM2 regulates aspects essential to cellular homeostasis in non-cancer tissues and, in some cases, promotes tissue-specific pathways in health and diseases. In pursuit of understanding the diverse tissue-specific roles of PKM2, investigations targeting tissues such as the kidney, liver, adipose, and pancreas have been conducted. Findings from these studies enhance our understanding of PKM2 functions in various diseases beyond cancer. Therefore, there is substantial interest in PKM2 modulation as a potential therapeutic target for the treatment of multiple conditions. Indeed, a vast plethora of research has focused on identifying therapeutic strategies for targeting PKM2. Recently, targeting PKM2 through its regulatory microRNAs, long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) has gathered increasing interest. Thus, the goal of this review is to highlight recent advancements in PKM2 research, with a focus on PKM2 regulatory microRNAs and lncRNAs and their subsequent physiological significance.

LncRNA TTN-AS1 Promotes Progression of Non-Small Cell Lung Cancer via Regulating miR-491-5p/ZNF503 Axis

Background

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer with high mortality worldwide. Long non-coding RNA (lncRNA) TTN antisense RNA1 (TTN-AS1) has been demonstrated to play a crucial role in a variety of cancers. This study was designed to investigate the function and molecular mechanism of lncRNA TTN-AS1 in NSCLC.

Methods

The expression levels of TTN-AS1, miR-491-5p and zinc finger protein 503 (ZNF503) were examined by quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot assay, respectively. Cell viability was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Cell migration and invasion were assessed by transwell assay. Epithelial-to-mesenchymal transition (EMT)-related proteins were measured using Western blot assay. The relationship between TTN-AS1, miR-491-5p and ZNF503 was predicted by starBase2.0 and confirmed by dual-luciferase reporter assay. Xenograft tumor experiment was conducted to analyze the tumor growth in vivo.

Results

The levels of TTN-AS1 and ZNF503 were up-regulated, while miR-491-5p expression was reduced in NSCLC tissues and cells. Knockdown of TTN-AS1 or ZNF503 suppressed cell proliferation, migration, invasion and EMT in NSCLC cells. Overexpression of ZNF503 reversed the effect of TTN-AS1 silencing on NSCLC progression. TTN-AS1 could modulate the expression of ZNF503 via sponging miR-491-5p. Furthermore, TTN-AS1 induced tumor growth in vivo.

Conclusion

Inhibition of TTN-AS1 hindered cell proliferation, migration, invasion and EMT in NSCLC cells by modulating miR-491-5p/ZNF503 axis, providing a promising biomarker for NSCLC treatment.

miR‑95 promotes osteosarcoma growth by targeting SCNN1A

Osteosarcoma (OS) is a common malignant bone tumor, presenting particularly in children and young adults, and accounts for approximately 19% of all malignant bone cancers. Despite advances in OS treatment, long-term prognosis remains poor. miRNAs are non-coding single-stranded RNAs ~22 nucleotides in length. Increasing evidence suggests that numerous miRNAs may play critical roles in tumorigenesis and tumor progression; however, the role of miR-95 in OS has not been examined. In the present study, we investigated the role of miR-95 in OS using in vitro and in vivo models and publicly available expression data. Our findings indicate that abnormal miR-95 expression occurs in OS, according to the Gene Expression Omnibus (GEO) database. The miR-95 inhibitor reduced cell proliferation and promoted apoptosis in OS cell lines as detected by EdU staining, TUNEL staining and flow cytometry. Furthermore, a dual luciferase reporter assay revealed that miR-95 regulates the cell cycle of OS cells and apoptosis by targeting sodium channel epithelial 1α subunit (SCNN1A). Additionally, miR-95 antagomir suppressed the growth of U2OS xenograft tumors in a mouse model. In summary, our results suggest that miR-95 induces OS growth in vitro and in vivo by targeting SCNN1A. Our results help clarify the mechanism underlying the miR-95-mediated effects on OS tumor growth, thus potentially establishing it as a diagnostic target.

Pyruvate kinase M2: A simple molecule with complex functions

Pyruvate kinase M2 is a critical enzyme that regulates cell metabolism and growth under different physiological conditions. In its metabolic role, pyruvate kinase M2 catalyzes the last glycolytic step which converts phosphoenolpyruvate to pyruvate with the generation of ATP. Beyond this metabolic role in glycolysis, PKM2 regulates gene expression in the nucleus, phosphorylates several essential proteins that regulate major cell signaling pathways, and contribute to the redox homeostasis of cancer cells. The expression of PKM2 has been demonstrated to be significantly elevated in several types of cancer, and the overall inflammatory response. The unusual pattern of PKM2 expression inspired scientists to investigate the unrevealed functions of PKM2 and the therapeutic potential of targeting PKM2 in cancer and other disorders. Therefore, the purpose of this review is to discuss the mechanistic and therapeutic potential of targeting PKM2 with the focus on cancer metabolism, redox homeostasis, inflammation, and metabolic disorders. This review highlights and provides insight into the metabolic and non-metabolic functions of PKM2 and its relevant association with health and disease.