Overexpression of FER1L4 promotes the apoptosis and suppresses epithelial-mesenchymal transition and stemness markers via activating PI3K/AKT signaling pathway in osteosarcoma cells

Interaction of ncRNAs and the PI3K/AKT/mTOR pathway: Implications for osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents, and is characterized by high heterogeneity, high malignancy, easy metastasis, and poor prognosis. Recurrence, metastasis, and multidrug resistance are the main problems that limit the therapeutic effect and prognosis of OS. PI3K/AKT/mTOR signaling pathway is often abnormally activated in OS tissues and cells, which promotes the rapid development, metastasis, and drug sensitivity of OS. Emerging evidence has revealed new insights into tumorigenesis through the interaction between the PI3K/AKT/mTOR pathway and non-coding RNAs (ncRNAs). Therefore, we reviewed the interactions between the PI3K/AKT/mTOR pathway and ncRNAs and their implication in OS. These interactions have the potential to serve as cancer biomarkers and therapeutic targets in clinical applications.

Functional role of MicroRNA/PI3K/AKT axis in osteosarcoma

Osteosarcoma (OS) is a primary malignant bone tumor that occurs in children and adolescents, and the PI3K/AKT pathway is overactivated in most OS patients. MicroRNAs (miRNAs) are highly conserved endogenous non-protein-coding RNAs that can regulate gene expression by repressing mRNA translation or degrading mRNA. MiRNAs are enriched in the PI3K/AKT pathway, and aberrant PI3K/AKT pathway activation is involved in the development of osteosarcoma. There is increasing evidence that miRNAs can regulate the biological functions of cells by regulating the PI3K/AKT pathway. MiRNA/PI3K/AKT axis can regulate the expression of osteosarcoma-related genes and then regulate cancer progression. MiRNA expression associated with PI3K/AKT pathway is also clearly associated with many clinical features. In addition, PI3K/AKT pathway-associated miRNAs are potential biomarkers for osteosarcoma diagnosis, treatment and prognostic assessment. This article reviews recent research advances on the role and clinical application of PI3K/AKT pathway and miRNA/PI3K/AKT axis in the development of osteosarcoma.

Regulation of the Epithelial to Mesenchymal Transition in Osteosarcoma

The epithelial to mesenchymal transition (EMT) is a cellular process that has been linked to the promotion of aggressive cellular features in many cancer types. It is characterized by the loss of the epithelial cell phenotype and a shift to a more mesenchymal phenotype and is accompanied by an associated change in cell markers. EMT is highly complex and regulated via multiple signaling pathways. While the importance of EMT is classically described for carcinomas-cancers of epithelial origin-it has also been clearly demonstrated in non-epithelial cancers, including osteosarcoma (OS), a primary bone cancer predominantly affecting children and young adults. Recent studies examining EMT in OS have highlighted regulatory roles for multiple proteins, non-coding nucleic acids, and components of the tumor micro-environment. This review serves to summarize these experimental findings, identify key families of regulatory molecules, and identify potential therapeutic targets specific to the EMT process in OS.

Biological impact and therapeutic perspective of targeting PI3K/Akt signaling in hepatocellular carcinoma: Promises and Challenges

Cancer progression results from activation of various signaling networks. Among these, PI3K/Akt signaling contributes to proliferation, invasion, and inhibition of apoptosis. Hepatocellular carcinoma (HCC) is a primary liver cancer with high incidence rate, especially in regions with high prevalence of viral hepatitis infection. Autoimmune disorders, diabetes mellitus, obesity, alcohol consumption, and inflammation can also lead to initiation and development of HCC. The treatment of HCC depends on the identification of oncogenic factors that lead tumor cells to develop resistance to therapy. The present review article focuses on the role of PI3K/Akt signaling in HCC progression. Activation of PI3K/Akt signaling promotes glucose uptake, favors glycolysis and increases tumor cell proliferation. It inhibits both apoptosis and autophagy while promoting HCC cell survival. PI3K/Akt stimulates epithelial-to-mesenchymal transition (EMT) and increases matrix-metalloproteinase (MMP) expression during HCC metastasis. In addition to increasing colony formation capacity and facilitating the spread of tumor cells, PI3K/Akt signaling stimulates angiogenesis. Therefore, silencing PI3K/Akt signaling prevents aggressive HCC cell behavior. Activation of PI3K/Akt signaling can confer drug resistance, particularly to sorafenib, and decreases the radio-sensitivity of HCC cells. Anti-cancer agents, like phytochemicals and small molecules can suppress PI3K/Akt signaling by limiting HCC progression. Being upregulated in tumor tissues and clinical samples, PI3K/Akt can also be used as a biomarker to predict patients' response to therapy.

The Role of Tumor Microenvironment in Regulating the Plasticity of Osteosarcoma Cells

Osteosarcoma (OS) is a malignancy that is becoming increasingly common in adolescents. OS stem cells (OSCs) form a dynamic subset of OS cells that are responsible for malignant progression and chemoradiotherapy resistance. The unique properties of OSCs, including self-renewal, multilineage differentiation and metastatic potential, 149 depend closely on their tumor microenvironment. In recent years, the likelihood of its dynamic plasticity has been extensively studied. Importantly, the tumor microenvironment appears to act as the main regulatory component of OS cell plasticity. For these reasons aforementioned, novel strategies for OS treatment focusing on modulating OS cell plasticity and the possibility of modulating the composition of the tumor microenvironment are currently being explored. In this paper, we review recent studies describing the phenomenon of OSCs and factors known to influence phenotypic plasticity. The microenvironment, which can regulate OSC plasticity, has great potential for clinical exploitation and provides different perspectives for drug and treatment design for OS.

Hydroxygenkwanin suppresses proliferation, invasion and migration of osteosarcoma cells via the miR‑320a/SOX9 axis

Hydroxygenkwanin (HGK) has an anticancer effect in a variety of tumors, but its role in osteosarcoma has not been explored. The purpose of the present study was to investigate the therapeutic effect of HGK on osteosarcoma and its specific molecular mechanism. Osteosarcoma cells (MG-63 and U2OS) treated with various concentrations of HGK were assigned to the treatment group. MTT, clone formation, wound healing and Transwell assays were performed to assess the viability, proliferation, migration, and invasion of MG-63 and U2OS cells. RT-qPCR was conducted to quantify the expression levels of of microRNA (miR)-320a and SRY-box transcription factor 9 (SOX9) in MG-63 and U2OS cells. The binding sites of miR-320a and SOX9 were predicted by starBase database, and verified using the dual-luciferase reporter assay. The expression levels of SOX9 and EMT-related proteins (N-cadherin, E-cadherin and vimentin) were detected by western blot analysis. HGK inhibited cell proliferation, migration, invasion, but promoted the expression of miR-320a in MG-63 and U2OS cells. Downregulation of miR-320a reversed the effects of HGK on proliferation, migration and invasion of MG-63 and U2OS cells, while upregulation of miR-320a had the opposite effect. HGK inhibited the expression of SOX9 by promoting the expression of miR-320a. Upregulation of SOX9 could partially reverse miR-320a-induced migration and invasion of MG-63 and U2OS cells. In addition, upregulation of miR-320a promoted E-cadherin expression and inhibited the expression of N-cadherin and vimentin, and the effect of miR-320a was also reversed by SOX9. In conclusion, HGK inhibited proliferation, migration and invasion of MG-63 and U2OS cells through the miR-320a/SOX9 axis.

Cisplatin and Exogenous Hydrogen Sulfide Inhibit the Progression of Osteosarcoma via EGFR/P13K/Akt Signaling Pathway

We attempted to analyze the effects of cisplatin and exogenous hydrogen on the invasion and proliferation of human osteosarcoma cells through EGFR/P13K/Akt signaling pathway. The effects of exogenous hydrogen sulfide and cisplatin on the invasion, apoptosis and proliferation of MG-63 cells were detected by transwell chamber invasion experiment, flow cytometry and CCK-8 method. After 24 and 48 hours of drug action, the inhibition rate of cell proliferation was significantly higher than in the combined treatment. The number of cells decreased significantly, compared with the control group. Western blotting and qRT-PCR showed that the expression of Akt mRNA in MG-63 cells treated with cisplatin+hydrogen sulfide at different concentrations for 48 hours decreased. The expression of Akt, P13K and EGFR were decreased Flow cytometry analysis showed that after the drug treatment of MG-63 cells, the S phase of cisplatin and cisplatin+exogenous hydrogen concentrations with different prolonged concentrations was significantly shortened phase and the G0/G1 was significantly, and the apoptosis rate of each group was significantly increased. Cisplatin and exogenous hydrogen sulfide can synergistically inhibit the proliferation and invasion of human osteosarcoma MG-63 cells, and regulate the apoptosis mechanism of MG-63 cells through EGFR/P13K/Akt signaling pathway.

FER1L4：A long non-coding RNA with multiple roles in the occurrence and development of tumors

BACKGROUND

FER-1 family member 4 (FER1L4), a 6.7 kb lncRNA located at 20q11.22, plays an important biological function in a variety of tumor diseases. The purpose of this review is to clarify the pathophysiological mechanism and potential biological function of FER1L4 in different tumors.

METHODS

By searching the relevant literature of PubMed, the specific pathophysiological mechanism of FER1L4 in different tumors was summarized.

RESULTS

LncRNA FER1L4 is one of the key factors in tumorigenesis and is abnormally down-regulated in many tumors, including osteosarcoma, lung cancer, laryngeal squamous cell carcinoma, laryngeal cancer, colorectal cancer, ovarian cancer, prostate cancer, esophageal cancer, gastric cancer, endometrial cancer, osteoarthritis, rheumatoid arthritis and so on. However, FER1L4 is downregulated in breast cancer, glioma, oral squamous cell carcinoma, renal clear cell carcinoma and periodontitis, and plays a protective role in orthodontic teeth. In addition, as a tumor suppressor gene or oncogene, FER1L4 affects tumor proliferation, invasion, migration and apoptosis. Conclusion：LncRNA FER1L4 has a good application prospect in the treatment and diagnosis of many kinds of tumors.

The Roles of Noncoding RNAs in the Development of Osteosarcoma Stem Cells and Potential Therapeutic Targets

Osteosarcoma (OS) is the common bone tumor in children and adolescents. Because of chemotherapy resistance, the OS patients have a poor prognosis. The one reason of chemotherapeutic resistance is the development of cancer stem cells (CSCs). CSCs represent a small portion of tumor cells with the capacity of self-renewal and multipotency, which are associated with tumor initiation, metastasis, recurrence and drug resistance. Recently, noncoding RNAs (ncRNAs) have been reported to critically regulate CSCs. Therefore, in this review article, we described the role of ncRNAs, especially miRNAs, lncRNAs and circRNAs, in regulating CSCs development and potential mechanisms. Specifically, we discussed the role of multiple miRNAs in targeting CSCs, including miR-26a, miR-29b, miR-34a, miR-133a, miR-143, miR-335, miR-382, miR-499a, miR-1247, and let-7days. Moreover, we highlighted the functions of lncRNAs in regulating CSCs in OS, such as B4GALT1-AS1, DANCR, DLX6-AS1, FER1L4, HIF2PUT, LINK-A, MALAT1, SOX2-OT, and THOR. Due to the critical roles of ncRNAs in regulation of OS CSCs, targeting ncRNAs might be a novel strategy for eliminating CSCs for OS therapy.

Prognostic biomarkers for predicting papillary thyroid carcinoma patients at high risk using nine genes of apoptotic pathway

Aberrant expressions of apoptotic genes have been associated with papillary thyroid carcinoma (PTC) in the past, however, their prognostic role and utility as biomarkers remains poorly understood. In this study, we analysed 505 PTC patients by employing Cox-PH regression techniques, prognostic index models and machine learning methods to elucidate the relationship between overall survival (OS) of PTC patients and 165 apoptosis related genes. It was observed that nine genes (ANXA1, TGFBR3, CLU, PSEN1, TNFRSF12A, GPX4, TIMP3, LEF1, BNIP3L) showed significant association with OS of PTC patients. Five out of nine genes were found to be positively correlated with OS of the patients, while the remaining four genes were negatively correlated. These genes were used for developing risk prediction models, which can be utilized to classify patients with a higher risk of death from the patients which have a good prognosis. Our voting-based model achieved highest performance (HR = 41.59, p = 3.36x10^-4, C = 0.84, logrank-p = 3.8x10^-8). The performance of voting-based model improved significantly when we used the age of patients with prognostic biomarker genes and achieved HR = 57.04 with p = 10⁻⁴ (C = 0.88, logrank-p = 1.44x10^-9). We also developed classification models that can classify high risk patients (survival ≤ 6 years) and low risk patients (survival > 6 years). Our best model achieved AUROC of 0.92. Further, the expression pattern of the prognostic genes was verified at mRNA level, which showed their differential expression between normal and PTC samples. Also, the immunostaining results from HPA validated these findings. Since these genes can also be used as potential therapeutic targets in PTC, we also identified potential drug molecules which could modulate their expression profile. The study briefly revealed the key prognostic biomarker genes in the apoptotic pathway whose altered expression is associated with PTC progression and aggressiveness. In addition to this, risk assessment models proposed here can help in efficient management of PTC patients.

Universal and cross-cancer prognostic biomarkers for predicting survival risk of cancer patients from expression profile of apoptotic pathway genes

Numerous cancer-specific prognostic models have been developed in the past, wherein one model is applicable for only one type of cancer. In this study, an attempt has been made to identify universal or multi-cancer prognostic biomarkers and develop models for predicting survival risk across different types of cancer patients. In order to accomplish this, we gauged the prognostic role of mRNA expression of 165 apoptosis-related genes across 33 cancers in the context of patient survival. Firstly, we identified specific prognostic biomarker genes for 30 cancers. The cancer-specific prognostic models achieved a minimum Hazard Ratio, HR_SKCM = 1.99 and maximum HR_THCA = 41.59. Secondly, a comprehensive analysis was performed to identify universal biomarkers across many cancers. Our best prognostic model consisted of 11 genes (TOP2A, ISG20, CD44, LEF1, CASP2, PSEN1, PTK2, SATB1, SLC20A1, EREG, and CD2) and stratified risk groups across 27 cancers (HR_OV = 1.53-HR_UVM = 11.74). The model was validated on eight independent cancer cohorts and exhibited a comparable performance. Further, we clustered cancer-types on the basis of shared survival related apoptosis genes. This approach proved helpful in development of cross-cancer prognostic models. To show its efficacy, a prognostic model consisting of 15 genes was thereby developed for LGG-KIRC pair (HR_KIRC = 3.27, HR_LGG = 4.23). Additionally, we predicted potential therapeutic candidates for LGG-KIRC high risk patients.

Proteomic Identification and Quantification of Snake Venom Biomarkers in Venom and Plasma Extracellular Vesicles

The global exploration of snakebites requires the use of quantitative omics approaches to characterize snake venom as it enters into the systemic circulation. These omics approaches give insights into the venom proteome, but a further exploration is warranted to analyze the venom-reactome for the identification of snake venom biomarkers. The recent discovery of extracellular vesicles (EVs), and their critical cellular functions, has presented them as intriguing sources for biomarker discovery and disease diagnosis. Herein, we purified EV’s from the snake venom (svEVs) of Crotalus atrox and C. oreganus helleri, and from plasma of BALB/c mice injected with venom from each snake using EVtrap in conjunction with quantitative mass spectrometry for the proteomic identification and quantification of svEVs and plasma biomarkers. Snake venom EVs from C. atrox and C. o. helleri were highly enriched in 5′ nucleosidase, L-amino acid oxidase, and metalloproteinases. In mouse plasma EVs, a bioinformatic analysis for revealed upregulated responses involved with cytochrome P450, lipid metabolism, acute phase inflammation immune, and heat shock responses, while downregulated proteins were associated with mitochondrial electron transport, NADH, TCA, cortical cytoskeleton, reticulum stress, and oxidative reduction. Altogether, this analysis will provide direct evidence for svEVs composition and observation of the physiological changes of an envenomated organism.

Long noncoding RNA KCNMB2-AS1 promotes the development of esophageal cancer by modulating the miR-3194-3p/PYGL axis

Esophageal cancer (ESCA), as a common cancer worldwide, is a main cause of cancer-related mortality. Comprehensive studies on molecular mechanism of ESCA have been carried out. Though numerous long noncoding RNAs (lncRNAs) was reported to participate in the occurrence and development of ESCA, the potential role of lncRNA potassium calcium-activated channel subfamily M regulatory beta subunit 2 (KCNMB2) antisense RNA 1 (KCNMB2-AS1) in ESCA remains to be discovered. This study intends to investigate the detailed function and molecular mechanism of KCNMB2-AS1 in ESCA. Gene expression was evaluated by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Cell proliferation was examined by Cell Counting Kit-8 (CCK-8) assay and colony formation assay. Cell invasion and migration were measured by wound healing assay and Transwell assay. Luciferase reporter assay was adopted to validate the interaction between KCNMB2-AS1 and miR-3194-3p. Western blotting was performed to assess protein levels. We discovered that KCNMB2-AS1 was significantly upregulated in ESCA. KCNMB2-AS1 downregulation suppressed the growth, invasion, migration and stemness of ESCA cells. KCNMB2-AS1 bound with miR-3194-3p, and glycogen phosphorylase L (PYGL) was a direct target of miR-3194-3p. KCNMB2-AS1 upregulated PYGL expression by directly binding with miR-3194-3p. Additionally, PYGL overexpression abolished the inhibitory influence of KCNMB2-AS1 depletion on ESCA cell behaviors. Collectively, lncRNA KCNMB2-AS1 promotes ESCA development through targeting the miR-3194-3p/ PYGL axis, which might provide theoretical basis to explore novel biomarkers for ESCA treatment.

lncRNA FER1L4 is dysregulated in osteoarthritis and regulates IL-6 expression in human chondrocyte cells

Osteoarthritis (OA) is the most prevalent joint disease and is one of the major causes of disability in the world. There has been an increase in the incidence of OA, which is associated with an aging population, sedentary lifestyle, and reduced physical activity. Due to the complex OA pathogenesis, there are limited diagnostic tools. OA is a degenerative joint disorder with a recognized inflammatory component, usually described as abnormal expression of inflammatory factors. For instance, interleukin 6 (IL‐6) has been shown to be upregulated in serum and synovial fluid among patients with OA. Most of the inflammatory factors have been associated with the expression of long noncoding RNAs (lncRNAs). However, the role of the novel lncRNA Fer-1-like protein 4 (FER1L4) in OA is yet to be determined. Here, we interrogated the expression profile of FER1L4 in patients with OA to define its potential application as a diagnostic marker. We collected synovial fluid and blood samples from both OA cases and normal controls. Using qRT-PCR, we evaluated the expression of FER1L4 in plasma and synovial fluid. On the other hand, the expression of IL-6 in plasma and synovial fluid was assessed using ELISA. Besides, the effect of age, gender or disease stage in the expression of the FER1L4 in plasma was also estimated. Moreover, the receiver operating characteristic (ROC) curves were used to determine the impact of FER1L4 in OA cases compared with the normal controls. In addition, we analyzed the correlation between FER1L4 and IL-6 through Pearson correlation analysis. Also, IL-6 expression in overexpressed FER1L4 samples was detected in chondrocytes through western blot analysis, while FER1L4 expression following endogenous IL-6 exposure was detected by qRT-PCR. Our data showed that whereas lncRNA FER1L4 is downregulated in OA patients, IL‐6 is upregulated. The plasma FER1L4 levels among the OA cases were suppressed with disease progression and old age, and the down-regulation could efficiently discriminate OA patients from normal subjects. In addition, upregulation of FER1L4 inhibited IL‐6 expression in human chondrocyte cells, and treatment with different concentrations of exogenous IL‐6 did not affect the expression of FER1L4. Taken together, our data demonstrates that FER1L4 could efficiently identify OA cases from normal subjects, and can also modulate the expression of IL‐6 in human chondrocytes.

Correlation between expression levels of lncRNA FER1L4 and RB1 in patients with colorectal cancer

Colorectal cancer (CRC) is a major life-threatening malignancy. Studies demonstrated the lncRNA fer-1 like family member 4 (FER1L4) was downregulated in different cancers and its expression was positively correlated with the retinoblastoma 1 (RB1) mRNA in a competing endogenous RNAs network. We investigated expression levels of FER1L4 and RB1 in patients with colorectal cancer. 50 paired colorectal tumors and non-tumor marginal tissues, 30 paired adenomatous colorectal polyps (ACPs) and matched adjacent normal tissues were obtained from the patients. Total RNA was extracted from the samples and cDNAs were synthesized. Their expression was quantified by qRT-PCR. Correlation between FER1L4 and RB1 expression levels was analyzed by Pearson correlation test. Finally, ROC curve analysis was used to evaluate their biomarker potency. We observed significant downregulation of FER1L4, but upregulation of RB1 in the colorectal tumors compared with non-tumor and the polyp tissues. However, RB1 expression was positively correlated with FER1L4 expression both in the tumor and polyp samples. ROC curve analysis showed both FER1L4 and RB1 expression levels could discriminate tumor from non-tumor and tumor from polyp samples. None of the clinicopathological characteristics of patients were associated with FER1L4 or RB1 expression levels. Despite the downregulation of FER1L4 and upregulation of RB1 in tumors compared with non-tumor tissues, the expression of RB1 was positively correlated with the expression of FER1L4 in the colorectal tumor as well as in the polyp tissues. FER1L4 expression level might be considered as a potential biomarker for colorectal cancer development.

The critical roles of lncRNAs in the development of osteosarcoma

Osteosarcoma is rare malignancy of childhood and adolescence, with high morbidity and mortality despite accomplishment of diverse therapeutic modalities. Identification of the underlying mechanism of osteosarcoma evolution would help in better management of this rare malignancy. Lots of investigations have described abnormal regulation of long non-coding RNAs (lncRNAs) in clinical specimens of osteosarcoma and the established cell lines. This malignancy has been associated with over-expression of TUG1, LOXL1-AS1, MIR100HG, NEAT1, HULC, ANRIL and a number of other lncRNAs, while under-expression of lots of lncRNAs including LncRNA-p21, FER1L4, GAS5, LncRNA NR_136400 and LINC-PINT. Expression amounts of LUCAT1, LINC00922, SNHG12, FOXC2-AS1 and OIP5-AS1 lncRNAs have been associated with response to a number of chemotherapeutic agents. Taken together, lncRNAs are possible targets for proposing novel advanced therapeutic modalities for osteosarcoma.

Gamabufotalin suppressed osteosarcoma stem cells through the TGF-β/periostin/PI3K/AKT pathway

AIMS

To investigate the effect of gamabufotalin (GBT) on metastasis and modulation of stemness features in osteosarcoma, and the molecular mechanisms underlying such effects.

METHODS

Human osteosarcoma U2OS/MG-63 cell lines were used in this study. Cell proliferation, migration, and invasion were determined by MTT assay, wound healing assay, and cell invasion assay, respectively. The inhibitive effect of GBT on stemness was assessed by flow cytometry and mammosphere formation. The protein levels of related proteins were detected by western blotting analysis. The effect of GBT on tumorigenicity and metastasis was determined by immunofluorescence staining and immunohistochemistry in vivo experiments.

RESULTS

We found that GBT suppressed the viability of U2OS/MG-63 cells in a time- and dose-dependent manner. Notably, GBT had no effect on the viability of human fetal osteoblastic (hFOB) 1.19 cells. Moreover, GBT increased the width of wounds, reduced the number of invasive osteosarcoma cells and reversed the epithelial-mesenchymal transition phenotype. Notably, we found that, compared with hFOB1.19 cells, the levels of transforming growth factor-β (TGF-β), periostin, phosphorylated-AKT (p-AKT), and phosphorylated-PI3K (p-PI3K) were higher in spheroids group than in parent cells. In addition, GBT reduced the ratio of CD133+ cells, the size of spheroids and Nanog, as well as the protein levels of SRY-box transcription factor 2 (SOX2), and octamer-binding protein 3/4 (OCT3/4). Our in vivo experiments showed that GBT consistently reduced lung metastasis lesions, the expression levels of matrix metalloproteinase 2 (MMP2), TGF-β, periostin, p-AKT, and p-PI3K (immunohistochemistry staining), as well as that of CD133 in tumor tissues (immunofluorescence analysis). From a mechanistic point of view, exogenous TGF-β/periostin/PI3K/AKT overexpression neutralized the reduction of GBT-decreased invasion/migration and the suppression of stemness properties.

CONCLUSION

Collectively, our data demonstrated that GBT inhibited the viability and tumorigenesis capability of osteosarcoma cells by blocking the TGF-β/periostin/PI3K/AKT signaling pathway. Therefore, GBT may represent a promising therapeutic agent for the management of osteosarcoma.

Functions of Vertebrate Ferlins

Ferlins are multiple-C2-domain proteins involved in Ca²⁺-triggered membrane dynamics within the secretory, endocytic and lysosomal pathways. In bony vertebrates there are six ferlin genes encoding, in humans, dysferlin, otoferlin, myoferlin, Fer1L5 and 6 and the long noncoding RNA Fer1L4. Mutations in DYSF (dysferlin) can cause a range of muscle diseases with various clinical manifestations collectively known as dysferlinopathies, including limb-girdle muscular dystrophy type 2B (LGMD2B) and Miyoshi myopathy. A mutation in MYOF (myoferlin) was linked to a muscular dystrophy accompanied by cardiomyopathy. Mutations in OTOF (otoferlin) can be the cause of nonsyndromic deafness DFNB9. Dysregulated expression of any human ferlin may be associated with development of cancer. This review provides a detailed description of functions of the vertebrate ferlins with a focus on muscle ferlins and discusses the mechanisms leading to disease development.

The lncRNA Fer1L4 is an adverse prognostic parameter in clear-cell renal-cell carcinoma

Purpose

Long non-coding RNAs (lncRNA) are involved in oncogenesis and tumor progression in various tumor entities. At present, little is known about the role in tumor biology of the lncRNA Fer-1 like family member 4 (Fer1L4) in clear-cell renal-cell carcinoma (ccRCC). The aim of this study is to evaluate the expression of Fer1L4 in patients with ccRCC, its association with clinicopathological parameters, and value as prognostic biomarker.

Material and methods

The expression of Fer1L4 was analyzed in the TCGA ccRCC cohort (n = 603; ccRCC n = 522, normal n = 81) and subsequently validated by quantitative real-time PCR in an independent cohort (n = 103, ccRCC n = 69, normal n = 34). Expression profiles were statistically correlated with clinicopathological and survival data.

Results

Fer1L4 lncRNA is overexpressed in ccRCC compared to adjacent normal tissues. Increased expression significantly correlates with tumor aggressiveness: high expression levels of Fer1L4 RNA were found in higher grade, higher stage, and metastatic tumors. Furthermore, Fer1L4 overexpression is an independent prognostic factor for overall, cancer-specific, and progression-free survival of patients with ccRCC.

Conclusion

Fer1L4 expression significantly correlates with aspects of tumor aggressiveness. Based on this impact on tumor progression and its influence as an independent prognostic factor, Fer1L4 appears to exert properties as an oncogene in ccRCC. As a prognostic tissue biomarker, further functional investigations are warranted to investigate Fer1L4 as a potential therapeutic target.

Acylglycerol kinase promotes tumour growth and metastasis via activating the PI3K/AKT/GSK3β signalling pathway in renal cell carcinoma

BACKGROUND

Clinically, the median survival in patients with metastatic renal cell carcinoma (RCC) was only 6-12 months and a 5-year survival rate of less than 20%. Therefore, an in-depth study of the molecular mechanisms involved in RCC is of great significance for improving the survival of patients with advanced RCC. Acylglycerol kinase (AGK) is a newly discovered lipid kinase that has been reported to be a potent oncogene that may be involved in the regulation of malignant progression in a variety of tumours. However, the expression and biological characteristics of the AGK gene in RCC remain unclear.

METHODS

AGK expression was quantified by quantitative real-time PCR, Western blotting and immunohistochemistry in RCC cell lines and paired patient tissues. Kaplan-Meier method and Cox proportional hazards models were used to evaluate the prognostic value of AGK in human RCC tissue samples. Chi-squared test was performed to analyse the correlation between AGK expression and the clinicopathological features. Stable overexpression and knockdown of AGK in RCC cells was constructed with lentivirus. The oncogenic effects of AGK in human RCC progression were investigated using assays of colony formation, anchorage-independent growth, EdU assay, cell cycle analysis, wound-healing, trans-well analysis and xenograft tumour model. GSEA and KEGG analysis were conducted to detect the potential pathway of AGK involved in RCC. These results were further confirmed using the luciferase reporter assays, immunofluorescence and in vivo experiments.

RESULTS

AGK expression is significantly elevated in RCC and closely related to the malignant development and poor prognosis in RCC patients. By in vitro and in vivo experiments, AGK was shown to enhance the proliferation of RCC cells by promoting the transition from the G1 phase to the S phase in the cell cycle and to enhance the migration and invasion by promoting epithelial-mesenchymal transition. By activating the PI3K/AKT/GSK3β signalling pathway in RCC, AGK can increase nuclear accumulation of β-catenin, which further upregulated TCF/LEF transcription factor activity.

CONCLUSIONS

AGK promotes the progression of RCC via activating the PI3K/AKT/GSK3β signalling pathway and might be a potential target for the further research of RCC.

Ferlin Overview: From Membrane to Cancer Biology

In mammal myocytes, endothelial cells and inner ear cells, ferlins are proteins involved in membrane processes such as fusion, recycling, endo- and exocytosis. They harbour several C2 domains allowing their interaction with phospholipids. The expression of several Ferlin genes was described as altered in several tumoural tissues. Intriguingly, beyond a simple alteration, myoferlin, otoferlin and Fer1L4 expressions were negatively correlated with patient survival in some cancer types. Therefore, it can be assumed that membrane biology is of extreme importance for cell survival and signalling, making Ferlin proteins core machinery indispensable for cancer cell adaptation to hostile environments. The evidences suggest that myoferlin, when overexpressed, enhances cancer cell proliferation, migration and metabolism by affecting various aspects of membrane biology. Targeting myoferlin using pharmacological compounds, gene transfer technology, or interfering RNA is now considered as an emerging therapeutic strategy.