MiR-520f promotes cell aggressiveness by regulating fibroblast growth factor 16 in hepatocellular carcinoma

Reprogramming of glucose metabolism via PFKFB4 is critical in FGF16-driven invasion of breast cancer cells

Fibroblast growth factors (FGFs) are expressed in both developing and adult tissues and play important roles in embryogenesis, tissue homeostasis, angiogenesis, and neoplastic transformation. Here, we report the elevated expression of FGF16 in human breast tumor and investigate its potential involvement in breast cancer progression. The onset of epithelial-mesenchymal transition (EMT), a prerequisite for cancer metastasis, was observed in human mammary epithelial cell-line MCF10A by FGF16. Further study unveiled that FGF16 alters mRNA expression of a set of extracellular matrix genes to promote cellular invasion. Cancer cells undergoing EMT often show metabolic alteration to sustain their continuous proliferation and energy-intensive migration. Similarly, FGF16 induced a significant metabolic shift toward aerobic glycolysis. At the molecular level, FGF16 enhanced GLUT3 expression to facilitate glucose transport into cells, which through aerobic glycolysis generates lactate. The bi-functional protein, 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase 4 (PFKFB4) was found to be a mediator in FGF16-driven glycolysis and subsequent invasion. Furthermore, PFKFB4 was found to play a critical role in promoting lactate-induced cell invasion since silencing PFKFB4 decreased lactate level and rendered the cells less invasive. These findings support potential clinical intervention of any of the members of FGF16-GLUT3-PFKFB4 axis to control the invasion of breast cancer cells.

FGF16 regulated by miR-520b enhances the cell proliferation of lung cancer

FGF16 is implicated in the progression of some specific types of cancers, such as embryonic carcinoma, ovarian cancer, and liver cancer. Yet, the function of FGF16 in the development of lung cancer remains largely unexplored. In this study, we present the novel function of FGF16 and the regulation of miR-520b on FGF16 in lung cancer progression. In clinical lung cancer tissues, FGF16 is overexpressed and its high level is negatively associated with the low level of miR-520b. Furthermore, both the transcription and translation levels of FGF16 are restrained by miR-520b in lung cancer cells. For the regulatory mechanism investigation, miR-520b is able to directly bind to the 3′-untranslated region (3′UTR) of FGF16 mRNA, leading to its mRNA cleavage in the cells. Functionally, miR-520b reduces the growth of lung cancer and its inhibitor anti-miR520b is able to promote the growth through competing endogenous miR-520b. Moreover, FGF16 silence using RNA interference is capable of doing great damage to anti-miR-520b-accelerated growth of lung cancer. Thus, our finding indicates that FGF16 is a new target gene of miR-520b in lung cancer. For lung cancer, FGF16 may serve as a novel biomarker and miR-520b/FGF16 may be useful in clinical treatment.

MicroRNA-3690 promotes cell proliferation and cell cycle progression by altering DKK3 expression in human thyroid cancer

An increasing amount of evidence has demonstrated the importance of microRNAs (miRNAs/miRs) in the tumorigenesis of malignant types of cancer, and data retrieved from The Cancer Genome Atlas database revealed that miR-3690 was upregulated in thyroid cancer (TC). The present study focused on the biological function and mechanism of miR-3690 in TC, demonstrating that miR-3690 expression was significantly elevated in TC cells and clinical tissues. Functional studies indicated that miR-3690 acted as an oncogene in TC by promoting cell proliferation, colony formation and cell cycle progression in association with the increased expression of cyclin E and c-myc. Mechanistically, prediction software indicated that Dickkopf-related protein 3 (DKK3) was a target of miR-3690, which was confirmed by the results of luciferase reporter assays and western blotting. DKK3 silencing abrogated the functions of miR-3690-in on TC cell proliferation. Collectively, the findings of the present study demonstrated that miR-3690 promoted TC cell proliferation and indicated miR-3690 as a potential biomarker and therapeutic target for TC.

MicroRNA-7 inhibits hepatocellular carcinoma cell invasion and metastasis by regulating Atg5-mediated autophagy

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors of the digestive system, with a low 5-year survival rate (5-9%). The abnormal expression of miRNA in liver cancer cells may play an important role in the pathophysiology of liver cancer. The ability of tumor invasion and metastasis is an important indicator to evaluate the degree of malignancy of HCC. Autophagy may affect the ability of tumor cells to invade and metastasize. Autophagy-related genes and proteins (Atg) are the core and key to regulating autophagy. The purpose of this study was to investigate the effect of microRNA-7 (miR-7) on targeting autophagy-related protein Atg5 to inhibit the effect of autophagy on the invasion and metastasis ability of liver cancer cells.

METHODS

The content of miR-7 and Atg5 in normal liver tissue and HCC tissues was detected by quantitative real-time polymerase chain (qRT-PCR). SMMC-7721 hepatoma cells were cultured in vitro, a starvation environment was simulated to activate autophagy, and transfection of cells was carried out by using miR-7 mimic, inhibitor, and autophagic inhibitor 3-MA. The RFP-GFP-LC3 double-labeled adenovirus infected hepatoma cells, and autophagy was detected by fluorescence microscopy. Western blot was used to detect the expression of LC3, Atg5, and the epithelial-mesenchymal transition (EMT)-related proteins (N-cadherin, vimentin, and snail). Transwell and plate cloning were used to detect the proliferation, invasion, and metastasis of hepatocarcinoma cells.

RESULTS

Expression of miR-7 (16.72±4.71, P<0.05) in HCC tissues was low, but the expression of Atg5 (13.70±2.80, P<0.05)was high. MiR-7 and Atg5 were highly negatively correlated in hepatoma tissues (r=-0.97). With the overexpression of hepatoma cells, the expression of Atg5 (0.49±0.07, F=395.26) and LC3II (0.51±0.06, F=23.58) was increased (P<0.05), and the autophagy was enhanced. As a result, the proliferation of hepatocarcinoma cells was decreased (t=3.22, P<0.05), the expression of EMT-related protein [N-cadherin (0.37±0.04), vimentin (0.60±0.07), snail (0.54±0.07)] was decreased (P<0.05), and hepatoma cell invasion and metastasis were decreased (n=6, F=162.28, P<0.05).

CONCLUSIONS

MiR-7 can inhibit the invasion and metastasis of hepatoma cells by targeting Atg5 to regulate autophagy.

Functional analysis of miR-767-5p during the progression of hepatocellular carcinoma and the clinical relevance of its dysregulation

Aberrant microRNA (miRNA) expression is a central hallmark of hepatocellular carcinoma (HCC) and identification of the mechanisms underlying the miRNA actions should provide invaluable resource for revealing the molecular basis of different malignant behaviors in HCC. Previous high-throughput analysis has identified miR-767-5p as a unique miRNA signature of HCC, but the biological relevance and corresponding molecular basis of miR-767-5p in HCC is still in its infancy. The current study was, therefore, designed to elucidate whether changes in miR-767-5p expression levels affect HCC pathogenesis, and to further identify the putative targets. miR-767-5p expression was observed to be upregulated by ~ 3.7-fold in surgical HCC specimens as compared to that in adjacent normal hepatic tissues, and this up-regulation trend correlated well to disease progression and predicted a poor prognosis in HCC patients. Functionally, miR-767-5p-overexpressing cells had a significantly higher proliferative, migratory, and invasive potential, and exhibited an enhanced anchorage-dependent clonogenesis and a tumor formation potential in vivo. Mechanistically, PMP22, a core component of integral membrane glycoprotein of peripheral nervous system myelin, was further identified as a direct down-stream target of miR-767-5p in HCC cells. Conversely, stable ectopic expression of PMP22 abrogated the promoting effects of miR-767-5p on HCC aggressive phenotype. Collectively, the available data suggest that as a potent oncomiR, miR-767-5p actions along HCC progression are in part mediated by its function as a posttranscriptional repressor of PMP22 signaling.

Overexpressing lncRNA SNHG16 inhibited HCC proliferation and chemoresistance by functionally sponging hsa-miR-93

Background

Long noncoding RNAs (lncRNAs) have been identified as prognostic biomarkers and functional regulators in human cancers. The present study aimed to determine the expressions and functions of an lncRNA, Small Nucleolar RNA Host Gene 16 (SNHG16), in hepatocellular carcinoma (HCC).

Patients and methods

SNHG16 expressions were tested by quantitative real-time PCR (qRT-PCR) in HCC cell lines, as well as 43 pairs of HCC tissues and pair-matched healthy hepatic tissues. It was overexpressed in Hep3B and HuH7 cells. The effects of SNHG16 overexpression in HCC in vitro proliferation, 5-fluorouracil (5-FU) chemoresistance, and in vivo tumor growth were tested. A potential microRNA (miRNA) sponge target of SNHG16, hsa-miR-93, was tested by luciferase reporter assay and qRT-PCR. In addition, hsa-miR-93 was upregulated in SNHG16-overexpressed HCC cells to examine its effect on SNHG16-mediated cancer cell functional regulation in HCC.

Results

SNHG16 levels were markedly downregulated in both HCC cell lines and HCC tissues. Lentivirus-mediated SNHG16 overexpression inhibited HCC cell proliferation, 5-FU chemoresistance, and in vivo tumor growth. Hsa-miR-93 was confirmed to be directly sponging on SNHG16. Its upregulation in HCC cells reversed SNHG16 overexpression and induced tumor-suppressing effects in HCC cells.

Conclusion

Our data demonstrate that SNHG16 plays a critical role in HCC development via functionally sponging hsa-miR-93.

Prospects of Noncoding RNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a global health problem and one of the most common malignant tumors. Recent studies have shown that noncoding RNAs (ncRNAs) contribute to the pathogenesis of hepatocellular carcinoma (HCC). These RNAs may be involved in a variety of pathological processes such as cell proliferation, apoptosis, angiogenesis, invasion, and metastasis. In addition, abnormal expression of ncRNAs in HCC may provide potential prognostic or diagnostic biomarkers. This review provides an overview of the role and potential applications of ncRNAs, miRNAs, lncRNAs, circRNAs, and snoRNAs in liver cancer.

miR‑188 suppresses tumor progression by targeting SOX4 in pediatric osteosarcoma

microRNA‑188 (miR‑188) acts as a tumor suppressor in various types of human cancer, including glioma, oral squamous cell carcinoma and hepatocellular carcinoma. However, the function and mechanism of miR‑188 in pediatric osteosarcoma (OS) have yet to be investigated. In the present study reverse transcription‑quantitative polymerase chain reaction revealed that miR‑188 expression was significantly downregulated in pediatric OS tissues and cell lines. miR‑188 overexpression markedly suppressed OS cell proliferation, migration and invasion, and induced cellular apoptosis. An in vivo assay demonstrated that miR‑188 overexpression inhibited tumor growth. miR‑188 targeted SOX4 to regulate its expression. miR‑188 expression was inversely correlated with SOX4 in pediatric OS tissues. SOX4 restoration abrogated the inhibitory effects of miR‑188 on OS cells. The results of the present study indicated that miR‑188 suppressed pediatric OS progression by targeting SOX4.

miR-455 Functions as a Tumor Suppressor Through Targeting GATA6 in Colorectal Cancer

Emerging evidence indicates that microRNAs (miRNAs) are often aberrantly expressed in human cancers. Meanwhile, the importance of miRNAs in regulating multiple cellular biological processes has been appreciated. The aim of this study was to investigate the significance of miR-455 and identify its possible mechanism in regulating colorectal cancer (CRC) progression. We found that the expression of miR-455 was sharply reduced in CRC tissues and cell lines. Importantly, the low expression of miR-455 was associated with poor overall survival of CRC patients. Overexpression of miR-455 in CRC cell lines significantly inhibited cell proliferation and migration in vitro. Moreover, GATA-binding protein 6 (GATA6), whose expression can be inversely regulated by miR-455 in CRC cell lines, was validated as a direct target of miR-455. Overall, our results revealed that miR-455 functions as a tumor suppressor, and its downregulation may contribute to CRC progression. Our study may provide a novel therapeutic target for CRC in the future.