MicroRNA-125b promotes tumor growth and suppresses apoptosis by targeting DRAM2 in retinoblastoma

Advancements in the diagnosis, prognosis, and treatment of retinoblastoma

Retinoblastoma (RB) is a prevalent primitive intraocular malignancy in children, particularly in those younger than age 3 years. RB is caused by mutations in the RB1 gene. In developing countries, mortality rates for this type of cancer are still high, whereas industrialized countries have achieved a survival rate of >95%-98%. Untreated, the condition can be fatal, underscoring the importance of early diagnosis. The existing treatments primarily consist of surgery, radiotherapy, and chemotherapy. The detrimental effects of radiation and chemotherapeutic drugs have been documented as factors that contribute to increased mortality rates and negatively affect the quality of life for patients. MicroRNA (miRNA), a type of noncoding RNA, exerts a substantial influence on RB development and the emergence of treatment resistance by regulating diverse cellular processes. This review highlights recent developments in the involvement of miRNAs in RB. This encompasses the clinical significance of miRNAs in the diagnosis, prognosis, and treatment of RB. Additionally, this paper examines the regulatory mechanisms of miRNAs in RB and explores potential therapeutic interventions. This paper provides an overview of the current and emerging treatment options for RB, focusing on recent studies investigating the application of different types of nanoparticles for the diagnosis and treatment of this condition.

Integration of human stem cell-derived in vitro systems and mouse preclinical models identifies complex pathophysiologic mechanisms in retinal dystrophy

Rare DRAM2 coding variants cause retinal dystrophy with early macular involvement via unknown mechanisms. We found that DRAM2 is ubiquitously expressed in the human eye and expression changes were observed in eyes with more common maculopathy such as Age-related Macular Degeneration (AMD). To gain insights into pathogenicity of DRAM2-related retinopathy, we used a combination of in vitro and in vivo models. We found that DRAM2 loss in human pluripotent stem cell (hPSC)-derived retinal organoids caused the presence of additional mesenchymal cells. Interestingly, Dram2 loss in mice also caused increased proliferation of cells from the choroid in vitro and exacerbated choroidal neovascular lesions in vivo. Furthermore, we observed that DRAM2 loss in human retinal pigment epithelial (RPE) cells resulted in increased susceptibility to stress-induced cell death in vitro and that Dram2 loss in mice caused age-related photoreceptor degeneration. This highlights the complexity of DRAM2 function, as its loss in choroidal cells provided a proliferative advantage, whereas its loss in post-mitotic cells, such as photoreceptor and RPE cells, increased degeneration susceptibility. Different models such as human pluripotent stem cell-derived systems and mice can be leveraged to study and model human retinal dystrophies; however, cell type and species-specific expression must be taken into account when selecting relevant systems.

miRNAs as potential game-changers in retinoblastoma: Future clinical and medicinal uses

Retinoblastoma (RB) is a rare tumor in children, but it is the most common primitive intraocular malignancy in childhood age, especially those below three years old. The RB gene (RB1) undergoes mutations in individuals with RB. Although mortality rates remain high in developing countries, the survival rate for this type of cancer is greater than 95-98% in industrialized countries. However, it is lethal if left untreated, so early diagnosis is essential. As a non-coding RNA, miRNA significantly impacts RB development and treatment resistance because it can control various cellular functions. In this review, we illustrate the recent advances in the role of miRNAs in RB. That includes the clinical importance of miRNAs in RB diagnosis, prognosis, and treatment. Moreover, the regulatory mechanisms of miRNAs in RB and therapeutic interventions are discussed.

Non-coding RNAs and Exosomal Non-coding RNAs in Traumatic Brain Injury: the Small Player with Big Actions

Nowadays, there is an increasing concern regarding traumatic brain injury (TBI) worldwide since substantial morbidity is observed after it, and the long-term consequences that are not yet fully recognized. A number of cellular pathways related to the secondary injury in brain have been identified, including free radical production (owing to mitochondrial dysfunction), excitotoxicity (regulated by excitatory neurotransmitters), apoptosis, and neuroinflammatory responses (as a result of activation of the immune system and central nervous system). In this context, non-coding RNAs (ncRNAs) maintain a fundamental contribution to post-transcriptional regulation. It has been shown that mammalian brains express high levels of ncRNAs that are involved in several brain physiological processes. Furthermore, altered levels of ncRNA expression have been found in those with traumatic as well non-traumatic brain injuries. The current review highlights the primary molecular mechanisms participated in TBI that describes the latest and novel results about changes and role of ncRNAs in TBI in both clinical and experimental research.

Ginsenoside Rb2 suppresses cellular senescence of human dermal fibroblasts by inducing autophagy

Background

Ginsenoside Rb2, a major active component of Panax ginseng, has various physiological activities, including anticancer and anti-inflammatory effects. However, the mechanisms underlying the rejuvenation effect of Rb2 in human skin cells have not been elucidated.

Methods

We performed a senescence-associated β-galactosidase staining assay to confirm cellular senescence in human dermal fibroblasts (HDFs). The regulatory effects of Rb2 on autophagy were evaluated by analyzing the expression of autophagy marker proteins, such as microtubule-associated protein 1A/1B-light chain (LC) 3 and p62, using immunoblotting. Autophagosome and autolysosome formation was monitored using transmission electron microscopy. Autophagic flux was analyzed using tandem-labeled GFP-RFP-LC3, and lysosomal function was assessed with Lysotracker. We performed RNA sequencing to identify potential target genes related to HDF rejuvenation mediated by Rb2. To verify the functions of the target genes, we silenced them using shRNAs.

Results

Rb2 decreased β-galactosidase activity and altered the expression of cell cycle regulatory proteins in senescent HDFs. Rb2 markedly induced the conversion of LC3-Ⅰ to LC3-Ⅱ and LC3 puncta. Moreover, Rb2 increased lysosomal function and red puncta in tandem-labeled GFP-RFP-LC3, which indicate that Rb2 promoted autophagic flux. RNA sequencing data showed that the expression of DNA damage-regulated autophagy modulator 2 (DRAM2) was induced by Rb2. In autophagy signaling, Rb2 activated the AMPK-ULK1 pathway and inactivated mTOR. DRAM2 knockdown inhibited autophagy and Rb2-restored cellular senescence.

Conclusion

Rb2 reverses cellular senescence by activating autophagy via the AMPK-mTOR pathway and induction of DRAM2, suggesting that Rb2 might have potential value as an antiaging agent.

Role of non-coding RNAs and exosomal non-coding RNAs in retinoblastoma progression

Retinoblastoma (RB) is a rare aggressive intraocular malignancy of childhood that has the potential to affect vision, and can even be fatal in some children. While the tumor can be controlled efficiently at early stages, metastatic tumors lead to high mortality. Non-coding RNAs (ncRNAs) are implicated in a number of physiological cellular process, including differentiation, proliferation, migration, and invasion, The deregulation of ncRNAs is correlated with several diseases, particularly cancer. ncRNAs are categorized into two main groups based on their length, i.e. short and long ncRNAs. Moreover, ncRNA deregulation has been demonstrated to play a role in the pathogenesis and development of RB. Several ncRNAs, such as miR-491-3p, miR-613,and SUSD2 have been found to act as tumor suppressor genes in RB, but other ncRNAs, such as circ-E2F3, NEAT1, and TUG1 act as tumor promoter genes. Understanding the regulatory mechanisms of ncRNAs can provide new opportunities for RB therapy. In the present review, we discuss the functional roles of the most important ncRNAs in RB, their interaction with the genes responsible for RB initiation and progression, and possible future clinical applications as diagnostic and prognostic tools or as therapeutic targets.

The Clinical Spectrum and Disease Course of DRAM2 Retinopathy

Pathogenic variants in DNA-damage regulated autophagy modulator 2 gene (DRAM2) cause a rare autosomal recessive retinal dystrophy and its disease course is not well understood. We present two Slovenian patients harboring a novel DRAM2 variant and a detailed review of all 23 other patients described to date. Whole exome and whole genome sequencing were performed in the two patients, and both underwent ophthalmological examination with a 2-year follow-up. PubMed was searched for papers with clinical descriptions of DRAM2 retinopathy. Patient 1 was homozygous for a novel variant, p.Met1?, and presented with the acute onset of photopsia and retina-wide retinopathy at the age of 35 years. The patient was first thought to have an autoimmune retinopathy and was treated with mycophenolate mofetil, which provided some symptomatic relief. Patient 2 was compound heterozygous for p.Met1? and p.Leu246Pro and presented with late-onset maculopathy at the age of 59 years. On review, patients with DRAM2 retinopathy usually present in the third decade with central visual loss, outer retinal layer loss on optical coherence tomography and a hyperautofluorescent ring on fundus autofluorescence. Either cone–rod or rod–cone dystrophy phenotype is observed on electroretinography, reflecting the importance of DRAM2 in both photoreceptor types. Non-null variants can result in milder disease.

A Comprehensive Cancer-Associated MicroRNA Expression Profiling and Proteomic Analysis of Human Umbilical Cord Mesenchymal Stem Cell-Derived Exosomes

Background:

The mesenchymal stem cells (MSCs) have enormous therapeutic potential owing to their multi-lineage differentiation and self-renewal properties. MSCs express growth factors, cytokines, chemokines, and non-coding regulatory RNAs with immunosuppressive, anti-tumor, and migratory properties. MSCs also release several anti-cancer molecules via extracellular vesicles, that act as pro-apoptotic/tumor suppressor factors. This study aimed to identify the stem cell-derived secretome that could exhibit anti-cancer properties through molecular profiling of cargos in MSC-derived exosomes.

Methods:

Human umbilical cord mesenchymal stem cells (hUCMSCs) were isolated from umbilical cord tissues and culture expanded. Subsequently, exosomes were isolated from hUCMSC conditioned medium and characterized by DLS, electron microscopy. Western blot for exosome surface marker protein CD63 expression was performed. The miRNA profiling of hUCMSCs and hUCMSC-derived exosomes was performed, followed by functional enrichment analysis.

Results:

The tri-lineage differentiation potential, fibroblastic morphology, and strong expression of pluripotency genes indicated that isolated fibroblasts are MSCs. The isolated extracellular vesicles were 133.8 ± 42.49 nm in diameter, monodispersed, and strongly expressed the exosome surface marker protein CD63. The miRNA expression profile and gene ontology (GO) depicted the differential expression patterns of high and less-expressed miRNAs that are crucial to be involved in the regulation of apoptosis. The LCMS/MS data and GO analysis indicate that hUCMSC secretomes are involved in several oncogenic and inflammatory signaling cascades.

Conclusion:

Primary human MSCs released miRNAs and growth factors via exosomes that are increasingly implicated in intercellular communications, and hUCMSC-exosomal miRNAs have a critical influence in regulating cell death and apoptosis of cancer cells.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13770-022-00450-8.

MicroRNA hsa-miR-657 promotes retinoblastoma malignancy by inhibiting peroxisome proliferator-activated receptor alpha expression

Retinoblastoma is a familial inherited embryonic neuroretinal malignancy with a low survival rate and poor prognosis. Our study aimed to evaluate the potential interaction between microRNA miR-657 and the peroxisome proliferator-activated receptor alpha (PPARA) in retinoblastoma. Expression of miR-657 and PPARA was analyzed in retinoblastoma tissues and cells using RT-qPCR. Cell proliferation, apoptosis, and migration were measured in retinoblastoma cell lines, and xenografting experiments were performed using nude mice. Our study showed that miR-657 expression was markedly increased, whereas that of PPARA was markedly decreased in retinoblastoma. Additionally, PPARA knockdown enhanced the development of retinoblastoma. miR-657 enhanced the retinoblastoma tumorigenesis by directly inhibiting PPARA expression, suggesting that PPARA targeting by miR-657 facilitates retinoblastoma development by enhancing cell growth. This study provides novel insights into the miR-657- and PPARA-mediated mechanisms underlying retinoblastoma progression and suggests that the interaction between miR-657 and PPARA may serve as an effective target for therapeutic intervention.

Micro RNAs as potential biomarkers in tuberculosis: A systematic review

Tuberculosis (TB) remains a major infectious disease across the globe. With increasing TB infections and a rise in multi-drug resistance, rapid diagnostic modalities are required to achieve TB control. Radiological investigations and microbiological tests (microscopic examination, cartridge-based nucleic acid amplification tests, and cultures) are most commonly used to diagnose TB. Histopathological/cytopathological examinations are also required for an accurate diagnosis in many patients. The causative agent, Mycobacterium tuberculosis (Mtb), is known to circumvent the host's immune system. Circulating microRNAs (miRNAs) play a crucial role in biological pathways and can be used as a potential biomarker to detect tuberculosis. miRNAs are small non-coding RNAs and negatively regulate gene expression during post-transcriptional regulation. The differential expression of miRNAs in multiple clinical samples in tuberculosis patients may be helpful as potential disease biomarkers. This review summarizes the literature on miRNAs in various clinical samples as biomarkers for TB diagnosis.

The regulatory effects of clomiphene and tamoxifen on mTOR and LC3-II expressions in relation to autophagy in experimental polycystic ovary syndrome (PCOS)

BACKGROUND

Polycystic ovary syndrome (PCOS) is a metabolic disease that causes infertility due to anovulation in women in reproductive age. It is known that clomiphene citrate (CC) and tamoxifen citrate (TMX) induce ovulation in women with PCOS. In this study, we aimed to investigate the effects of CC and TMX on the autophagy pathway in PCOS.

METHODS AND RESULTS

Experimental PCOS model was induced by letrozole (1 mg/kg) in rats by gavage for 21 days. After the last letrozole administration, rats were treated TMX (1 mg/kg) or CC (1 mg/kg) for 5 days. At the end of the experimental procedures, rats in all groups were sacrificed and ovarian tissues were removed. It was observed that mRNA and protein expressions of LC3-II were significantly higher in TMX and CC groups than control and PCOS groups (p < 0.05), while mRNA and protein expressions of mTOR in TMX and CC groups were found significantly lower than control and PCOS groups (p < 0.05).

CONCLUSIONS

In conclusion, present study suggests that TMX and CC induce autophagy in ovaries with PCOS. Autophagy is a promising target for understanding pathophysiology of this disease and for developing more effective and safe new protocols for the treatment of PCOS-related anovulation.

Differential Circulating MicroRNA Expression in Age-Related Macular Degeneration

This study explored the expression of several miRNAs reported to be deregulated in age-related macular degeneration (AMD). Total RNA was isolated from sera from patients with dry AMD (n = 12), wet AMD (n = 14), and controls (n = 10). Forty-two previously investigated miRNAs were selected based on published data and their role in AMD pathogenesis, such as angiogenic and inflammatory effects, and were co-analysed using a miRCURY LNA miRNA SYBR^® Green PCR kit via quantitative real-time polymerase chain reaction (qRT-PCR) to validate their presence. Unsupervised hierarchical clustering indicated that AMD serum specimens have a different miRNA profile to healthy controls. We successfully validated the differentially regulated miRNAs in serum from AMD patients versus controls. Eight miRNAs (hsa-let-7a-5p, hsa-let-7d-5p, hsa-miR-23a-3p, hsa-miR-301a-3p, hsa-miR-361-5p, hsa-miR-27b-3p, hsa-miR-874-3p, hsa-miR-19b-1-5p) showed higher expression in the serum of dry AMD patients than wet AMD patients and compared with healthy controls. Increased quantities of certain miRNAs in the serum of AMD patients indicate that these miRNAs could potentially serve as diagnostic AMD biomarkers and might be used as future AMD treatment targets. The discovery of significant serum miRNA biomarkers in AMD patients would provide an easy screening tool for at-risk populations.

MiR-142-5p promotes retinoblastoma cell proliferation, migration and invasion by targeting PTEN

The study intends to probe the functions of miR-142-5p in retinoblastoma (RB) and the relationship between miR-142-5p and phosphatase and tensin homolog deleted on chromosome ten (PTEN). In our study, miR-142-5p and PTEN mRNA expression in RB tissue, serum of RB patients and RB cell lines were investigated by quantitative real-time polymerase chain reaction (qRT-PCR). The proliferation, migration, invasion and cell apoptosis were measured using MTT assay, BrdU assay, Transwell experiments and flow cytometry analysis, respectively. Binding sites between miR-142-5p and PTEN were predicted by the TargetScan database and were confirmed via qRT-PCR, western blot and dual-luciferase reporter gene assay. It was demonstrated that miR-142-5p expression was elevated in RB tissue, serum of RB patients and RB cell lines. MiR-142-5p overexpression remarkably promoted the proliferation, migration, invasion and inhibited the apoptosis of WERI-RB-1 cells while miR-142-5p knockdown induced opposite effects in Y79 cells. MiR-142-5p decreased PTEN expression in both mRNA and protein expression levels, and PTEN was identified as a target gene of miR-142-5p. Cotransfection of PTEN overexpression plasmids reversed the influences of miR-142-5p on RB cells. In conclusion, miR-142-5p enhances proliferation, migration and invasion of RB cell by targeting PTEN.

Interaction of microRNAs with sphingosine kinases, sphingosine-1 phosphate, and sphingosine-1 phosphate receptors in cancer

Sphingosine-1-phosphate (S1P), a pleiotropic lipid mediator, participates in various cellular processes during tumorigenesis, including cell proliferation, survival, drug resistance, metastasis, and angiogenesis. S1P is formed by two sphingosine kinases (SphKs), SphK1 and SphK2. The intracellularly produced S1P is delivered to the extracellular space by ATP-binding cassette (ABC) transporters and spinster homolog 2 (SPNS2), where it binds to five transmembrane G protein-coupled receptors to mediate its oncogenic functions (S1PR1-S1PR5). MicroRNAs (miRNAs) are small non-coding RNAs, 21-25 nucleotides in length, that play numerous crucial roles in cancer, such as tumor initiation, progression, apoptosis, metastasis, and angiogenesis via binding to the 3'-untranslated region (3'-UTR) of the target mRNA. There is growing evidence that various miRNAs modulate tumorigenesis by regulating the expression of SphKs, and S1P receptors. We have reviewed various roles of miRNAs, SphKs, S1P, and S1P receptors (S1PRs) in malignancies and how notable miRNAs like miR-101, miR-125b, miR-128, and miR-506, miR-1246, miR-21, miR-126, miR499a, miR20a-5p, miR-140-5p, miR-224, miR-137, miR-183-5p, miR-194, miR181b, miR136, and miR-675-3p, modulate S1P signaling. These tumorigenesis modulating miRNAs are involved in different cancers including breast, gastric, hepatocellular carcinoma, prostate, colorectal, cervical, ovarian, and lung cancer via cell proliferation, invasion, angiogenesis, apoptosis, metastasis, immune evasion, chemoresistance, and chemosensitivity. Therefore, understanding the interaction of SphKs, S1P, and S1P receptors with miRNAs in human malignancies will lead to better insights for miRNA-based cancer therapy.

Ubiquitin specific peptidase 33 promotes cell proliferation and reduces apoptosis through regulation of the SP1/PI3K/AKT pathway in retinoblastoma

Ubiquitin-specific protease 33 (USP33), a deubiquitinating enzyme (DUB), has been identified to serve as a tumor suppressor or an oncogene in different cancers. However, its role in retinoblastoma (RB) remains unknown. Here, we aimed to uncover USP33 expression profile and function in RB, and disclose the underlying mechanism. USP33 levels in RB tissues and cells were determined using RT-qPCR and western blotting assays. USP33 effects on cell growth, cycle, apoptosis and tumorigenesis were studied using MTT, Edu, cycle and western blotting and in vivo assays. The results showed that USP33 expression levels were elevated in RB tissues and cells as compared with normal retinal tissues and cells. Downregulation of USP33 in RB Y79 and WERI-RB1 cells leaded to significant increases in cell apoptosis, G1 phase arrest and tumorigenesis, and reductions in cell growth and G2 and S phase arrest, as well as inhibited the activation of the PI3K/AKT signaling. SP1 overexpression abolished the roles of USP33 downregulation in modulating the activation of PI3K/AKT signaling, cell growth, apoptosis, and cell cycle. This study uncovered that USP33 promoted the progression of RB through regulation of the SP1/PI3K/AKT pathway.

KCNQ1OT1 accelerates gastric cancer progression via miR-4319/DRAM2 axis

INTRODUCTION

This work was to explore the connection of KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) and microRNA-4319 (miR-4319), and to investigate the associated underlying mechanisms in gastric cancer (GC) progression.

METHODS

Quantitative real-time PCR was performed to measure KCNQ1OT1, miR-4319 and DNA-damage regulated autophagy modulator 2 (DRAM2) expression levels in GC cells. Moreover, expression level of KCNQ1OT1 and DRAM2 in GC tissues was analyzed at ENCORI website (http://starbase.sysu.edu.cn/index.php). Cell proliferation, colony formation assay and flow cytometry assays were performed to analyze effects of KCNQ1OT1, miR-4319 and DRAM2 on cell growth and death. Dual-luciferase activity reporter assay and RNA immunoprecipitation assay was conducted to verify the interactions of KCNQ1OT1 or DRAM2 and miR-4319.

RESULTS AND CONCLUSION

We found KCNQ1OT1 level was increased in tumor tissues and cells. Force the expression of KCNQ1OT1 promotes, while knockdown KCNQ1OT1 inhibits GC cell growth. Further studies indicated miR-4319 functioned as a bridge between KCNQ1OT1 and DRAM2. Finally, we showed KCNQ1OT1/miR-4319/DRAM2 axis regulates GC cell growth in vitro and in vivo. lncRNA KCNQ1OT1 promotes GC progression by sponging miR-4319 to upregulate DRAM2, indicating KCNQ1OT1 might be a promising target for GC treatment.

MicroRNA-9 inhibits proliferation and progression in retinoblastoma cells by targeting PTEN

BACKGROUND

Retinoblastoma (RB) is the most prevalent primary intraocular malignancy, which commonly occurs during infant and childhood.

OBJECTIVE

Our study aimed to investigate whether microRNA-9 (miR-9) could regulate RB cells and its mechanism.

METHODS

qRT-PCR analysis was used to detect the expression of miR-9. In addition, to detect the migration of RB cells, wound healing assay was conducted. Xenograft tumor models in nude mice were also established, in order to assess the effects of miR-9 on tumor growth. qRT-PCR, luciferase reporter assay and western blot analysis were used to detect the target of miR-9.

RESULTS

Initially, the expression level of miR-9 was significantly decreased in the RB tissues and blood samples from patients with RB. qRT-PCR, luciferase reporter assay and western blot analysis were used to confirm that PTEN was the target genes of miR-9 and it was negatively regulated by miR-9. When the expression of miR-9 was up-regulated, the cell viability, proliferation, migration and tumor formation were significantly suppressed. Furthermore, the expression level of PTEN was decreased after transfection of miR-9 mimic. Taken together, these results indicated that miR-9 might suppress the cell viability, proliferation, migration and tumor formation in RB by inhibiting PTEN.

CONCLUSION

The in vitro and in vivo experiments demonstrated that miR-9 acts as a tumor suppressor function in RB cells and might serve as novel therapeutic targets for the treatment of RB.

CircMKLN1 Suppresses the Progression of Human Retinoblastoma by Modulation of miR-425-5p/PDCD4 Axis

Purpose: Circular RNAs (circRNAs) are essential regulators in tumorigenesis and development. In this study, we focused on the functions of circRNA muskelin 1 (circMKLN1) in retinoblastoma (RB) progression.Materials and Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) assay was conducted to determine the levels of circMKLN1, microRNA-425-5p (miR-425-5p) and programmed cell death 4 (PDCD4). The characteristic of circMKLN1 was analyzed using RNase R assay. Cell Counting Kit-8 (CCK-8) assay and colony formation assay were employed to explore cell proliferation ability. The transwell assay was utilized for cell migration and invasion. A Western blot assay was performed for protein levels. The dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were conducted to demonstrate the relationships among circMKLN1, miR-425-5p and PDCD4. Murine xenograft model assay was adopted to investigate the role of circMKLN1 in vivo.Results: CircMKLN1 was downregulated in RB tissues and cells. High levels of circMKLN1 were related to a favorable outcome of RB patients. CircMKLN1 was resistant to RNase R digestion and circMKLN1 overexpression repressed RB cell proliferation, migration and invasion in vitro. MiR-425-5p was identified as the target of circMKLN1 and miR-425-5p elevation reversed the effects of circMKLN1 overexpression on RB cell malignant behaviors. Furthermore, as the target gene of miR-425-5p, PDCD4 silencing could ameliorate the suppressive roles of circMKLN1 in RB cell growth and metastasis. Additionally, circMKLN1 overexpression hampered tumor growth in vivo.Conclusions: CircMKLN1 overexpression decelerated the progression of RB through sponging miR-425-5p and elevating PDCD4.

A Novel Circular RNA circCSPP1 Promotes Liver Cancer Progression by Sponging miR-1182

INTRODUCTION

Aberrant circular RNA (circRNA) expression has been extensively discovered for its involvement in both the initiation and progression of various cancers. Through screening circRNA profile, we identified a novel circRNA has_circ_0001806, which is termed as circCSPP1 in liver cancer. In the present study, we aim to investigate the role of circCSPP1 in the progression of liver cancer.

METHODS

Fluorescence in situ hybridization (FISH) was used to detect the location of circCSPP1. Function studies including MTT, colony formation assay, transwell assay and flow cytometry were carried out to detect the malignant behaviour of circCSPP1 on liver cancer cells. Luciferase assay and RNA pull down were used to detect the interaction between miR-1182 and circCSPP1 as well as RAB15. Quantitative realtime (qPCR) and Western blot were performed to evaluate the RNA and protein expression, respectively.

RESULTS

CircCSPP1 knockdown inhibited the proliferation, migration and invasion while promoted apoptosis of liver cancer cells. Mechanically, we predicted and verified the target miR of circCSPP1 which is miR-1182. miR-1182 was capable of reversing the effect of circCSPP1 on liver cancer cells. Moreover, miR-1182 was found to also target RAB15 to participate in the regulation of cell phenotype.

DISCUSSION

Taken together, circCSPP1 promoted progression of liver cancer cells via sponging miR-1182 which may serve as a novel prognostic and therapeutic target for liver cancer.

An Analysis of Mechanisms for Cellular Uptake of miRNAs to Enhance Drug Delivery and Efficacy in Cancer Chemoresistance

Up until recently, it was believed that pharmaceutical drugs and their metabolites enter into the cell to gain access to their targets via simple diffusion across the hydrophobic lipid cellular membrane, at a rate which is based on their lipophilicity. An increasing amount of evidence indicates that the phospholipid bilayer-mediated drug diffusion is in fact negligible, and that drugs pass through cell membranes via proteinaceous membrane transporters or carriers which are normally used for the transportation of nutrients and intermediate metabolites. Drugs can be targeted to specific cells and tissues which express the relevant transporters, leading to the design of safe and efficacious treatments. Furthermore, transporter expression levels can be manipulated, systematically and in a high-throughput manner, allowing for considerable progress in determining which transporters are used by specific drugs. The ever-expanding field of miRNA therapeutics is not without its challenges, with the most notable one being the safe and effective delivery of the miRNA mimic/antagonist safely to the target cell cytoplasm for attaining the desired clinical outcome, particularly in miRNA-based cancer therapeutics, due to the poor efficiency of neo-vascular systems revolting around the tumour site, brought about by tumour-induced angiogenesis. This acquisition of resistance to several types of anticancer drugs can be as a result of an upregulation of efflux transporters expression, which eject drugs from cells, hence lowering drug efficacy, resulting in multidrug resistance. In this article, the latest available data on human microRNAs has been reviewed, together with the most recently described mechanisms for miRNA uptake in cells, for future therapeutic enhancements against cancer chemoresistance.

Roles of the microRNA‑338‑3p/NOVA1 axis in retinoblastoma

Retinoblastoma (RB) is an intraocular malignancy that mainly affects young children. Previous reports have demonstrated that mutations or the inactivation of the RB1 gene were the main cause of RB; however, disruption of the intracellular signaling pathways following deficiency of RB1 requires further investigation. Based on the Gene Expression Omnibus data and bioinformatics prediction, the present study aimed to investigate the microRNA (miR)-338-3p/neuro-oncological ventral antigen 1 (NOVA1) axis in RB. Subsequently, overexpression and knockdown of miR-338-3p and NOVA1, respectively, were performed to study the role of miR-338-3p/NOVA1 in the progression of the RB cells. The results demonstrated that overexpression of miR-338-3p significantly inhibited cell proliferation, migration and invasion, and promoted apoptosis of the RB cells. Moreover, knockdown of NOVA1 showed similar results. A dual-luciferase reporter assay and rescue experiments further confirmed the direct binding between miR-338-3p and NOVA1. Taken together, the results indicated that miR-338-3p acted as tumor suppressor by targeting the oncogene of NOVA1 in RB, which may serve as potential therapeutic targets in RB.

Circular RNA hsa_circ_0000034 promotes the progression of retinoblastoma via sponging microRNA-361-3p

Retinoblastoma is the commonest eye cancer occurring in the pediatric population. Circular RNAs (circRNAs) are essential regulators of tumorigenesis and development. The current experiment delves into the function and molecular basis of hsa_circ_0000034 in retinoblastoma progression. In the study, these series of experiments noted an upregulation of hsa_circ_0000034 in retinoblastoma cell lines and tissues. Retinoblastoma patients with raised hsa_circ_0000034 expressions were more likely to possess a more progressive International Integrated Reporting Council (IIRC) stage and optic nerve invasion. hsa_circ_0000034 knockdown caused a marked suppression in the proliferation and invasion of retinoblastoma cells in vitro. Mechanistically, hsa_circ_0000034 appeared to serve as a competitive endogenous RNA (ceRNA) in retinoblastoma through miR-361-3p sponging. In conclusion, our data proved that hsa_circ_0000034 promoted the oncogenicity of retinoblastoma via regulation of miR-361-3p expression, a finding that may contribute toward retinoblastoma therapeutics.

Dexmedetomidine inhibits inflammatory response and autophagy through the circLrp1b/miR-27a-3p/Dram2 pathway in a rat model of traumatic brain injury

Circular RNAs (circRNAs) have a regulatory function on inflammation and autophagy, of which rno-circRNA_010705 (circLrp1b) appears to be significantly up-regulated following traumatic brain injury (TBI). Dexmedetomidine (DEX) shows improvement effects in TBI by inhibiting NLRP3/caspase-1. However, whether circLrp1b plays critical roles in DEX-mediated TBI attenuation and the underlying mechanisms remain unclear. After TBI was established in rats by controlled cortical impact (CCI) to cause brain trauma, they received an intracerebroventricular injection of lentiviral vector, followed by intraperitoneal injection of DEX. Administration of DEX ameliorated autophagy in rats following TBI, accompanied by up-regulated circLrp1b and Dram2 and down-regulated miR-27a-3p. DEX promoted the effects of circLrp1b in attenuating TBI-induced neurologic impairment, autophagy, and inflammation, which was significantly reversed by inhibition of miR-27a-3p or Dram2 overexpression. Mechanistically, northern blot and luciferase reporter assays indicated that circLrp1b up-regulated Dram2 expression by functioning as a sponge for miR-27a-3p to promote autophagy involved in TBI, which was reversed by DEX treatment. Collectively, this study demonstrated that DEX inhibits inflammatory response and autophagy involved in TBI in vivo through inactivation of the circLrp1b/miR-27a-3p/Dram2 signaling pathway.

Silencing miR-125b-5p attenuates inflammatory response and apoptosis inhibition in mycobacterium tuberculosis-infected human macrophages by targeting DNA damage-regulated autophagy modulator 2 (DRAM2)

Tuberculosis is one of the most important infectious diseases worldwide and macrophage apoptosis is the major host defense mechanism against TB. We attempted to characterize the role of miRNA (miR)-125b-5p on mycobacterium tuberculosis (Mtb) infection and macrophages behaviors in vitro. According to fluorescence-activated cell separation (FACS), primary monocytes (CD14⁺) in TB patients were accumulated, and apoptotic monocytes were decreased. Peripheral blood mononuclear cells (PBMCs)-derived macrophages (MDMs) and monocytic cells THP-1-derived macrophage-like cells (TDMs) in vitro were used to be infected with H37Rv. After infection, colony-forming units assay revealed the increase of bacterial activity, FACS demonstrated the decrease of apoptosis rate of MDMs and TDMs, as well as promoted levels of IL-6, TNF-α, Bax, and Bim and suppressed levels of IL-10 and Bcl-2, examined by enzyme-linked immunosorbent assay (ELISA) and western blot assay. Expression of miR-125b-5p and DNA damage-regulated autophagy modulator 2 (DRAM2) was examined, and real-time PCR and western blot assay showed that miR-125b-5p was upregulated, whereas DRAM2 was downregulated in primary monocytes and H37Rv-infected macrophages (MDMs and TDMs). Moreover, blocking miR-125b-5p could attenuated H37Rv-induced bacterial activity and inflammatory response of MDMs and TDMs, accompanied with apoptosis inhibition. Whereas these effects of miR-125b-5p knockdown were abolished by downregulating DRAM2. In mechanism, DRAM2 was a downstream target of miR-125b-5p, as evidenced by dual-luciferase reporter assay. Collectively, silencing miR-125b-5p could protect human macrophages against Mtb infection through promoting apoptosis and inhibiting inflammatory response via targeting DRAM2, suggesting a novel target for Mtb eliminating. Abbreviations: TB: tuberculosis; PBMCs: peripheral blood mononuclear cells; Mtb: mycobacterium tuberculosis; AFB: acid fast bacilli; FITC: fluorescein isothiocyanate; MDMs: monocytes-derived macrophages; TDMs: THP-1-derived macrophage-like cells; ERFP: Mtb-enhanced red fluorescent protein; CFU: colony-forming units; ELISA: enzyme-linked immunosorbent assay; FACS: fluorescence-activated cell separation; PI: propidium iodide; DRAM2: DNA damage-regulated autophagy modulator 2; Real-time PCR: real-time polymerase chain reaction; in-miR-125b-5p: miR-125b-5p inhibitor; si-DRAM2: siRNA against DRAM2.

Inhibition of MicroRNA 6937 Delays Photoreceptor and Vision Loss in a Mouse Model of Retinitis Pigmentosa

Inherited retinal dystrophies (IRDs) are a group of rare retinal conditions, including retinitis pigmentosa (RP), caused by monogenic mutations in 1 out of more than 250 genes. Despite recent advancements in gene therapy, there is still a lack of an effective treatment for this group of retinal conditions. MicroRNAs (miRNAs) are a class of highly conserved small non-coding RNAs that inhibit gene expression. Control of miRNAs-mediated protein expression has been described as a widely used mechanism for post-transcriptional regulation in many physiological and pathological processes in different organs, including the retina. Our main purpose was to test the hypothesis that modulation of a group of miRNAs can protect photoreceptor cells from death in the rd10 mouse model of retinitis pigmentosa. For this, we incorporated modulators of three miRNAs in adeno-associated viruses (AAVs), which were administered through sub-retinal injections. The results obtained indicate that inhibition of the miR-6937-5p slows down the visual deterioration of rd10 mice, reflected by an increased electroretinogram (ERG) wave response under scotopic conditions and significant preservation of the outer nuclear layer thickness. This work contributes to broadening our knowledge on the molecular mechanisms underlying retinitis pigmentosa and supports the development of novel therapeutic approaches for RP based on miRNA modulation.

Downregulation of microRNA-224-3p Hampers Retinoblastoma Progression via Activation of the Hippo-YAP Signaling Pathway by Increasing LATS2

Purpose

The pivotal role of microRNAs (miRNAs or miRs) has been proved in the pathogenesis of retinoblastoma. miR-224-3p is demonstrated to be involved in several tumors. However, the underlying mechanism of miR-224-3p in retinoblastoma is yet to be investigated. Therefore, this study was designed to identify the regulation of miR-224-3p in human retinoblastoma.

Methods

The expression pattern of miR-224-3p and large tumor suppressor 2 (LATS2) in retinoblastoma was measured by reverse transcription quantitative polymerase chain reaction. Afterward, the interaction between miR-224-3p and LATS2 was identified using a dual luciferase reporter gene assay. Next, gain-of-function and loss-of-function approaches were employed to examine the effects of miR-224-3p and LATS2 as well as their interaction on cell apoptosis, proliferation and angiogenesis abilities, and tumorigenesis. Whether the Hippo-YAP signaling pathway was involved in tumorigenesis was analyzed by determining downstream genes.

Results

LATS2 was downregulated in retinoblastoma, and its overexpression promoted apoptosis and suppressed proliferation of retinoblastoma cells. miR-224-3p, highly expressed in retinoblastoma, inhibited the expression of its target gene LATS2, which inhibited activation of the Hippo-YAP signaling pathway. Suppression of miR-224-3p promoted apoptosis while suppressing the proliferation of retinoblastoma cells and angiogenesis. Tumor progression induced by upregulation of miR-224-3p was diminished by restoration of LATS2. It was observed that tumor growth and angiogenesis were reduced by depleted miR-224-3p in the animal experiments.

Conclusions

The present study suggests that miR-224-3p targets LATS2 and blocks the Hippo-YAP signaling pathway activation, thus preventing the progression of retinoblastoma, which could be a new therapeutic target for retinoblastoma.

CD24 blunts the sensitivity of retinoblastoma to vincristine by modulating autophagy

Retinoblastoma (RB) is the most common childhood malignant intraocular tumor. The clinical efficacy of vincristine (VCR) in the treatment of RB is severely limited by drug resistance. Here, we found that CD24, a GPI-anchored protein, was overexpressed in human RB tissues and RB cell lines, and was associated with the sensitivity of RB cells in response to VCR therapy. We demonstrated that CD24 plays a critical role in impairing RB sensitivity to VCR via regulating autophagy. Mechanistically, CD24 recruits PTEN to the lipid raft domain and regulates the PTEN/AKT/mTORC1 pathway to activate autophagy. Lipid raft localization was essential for CD24 recruitment function. Collectively, our findings revealed a novel role of CD24 in regulating RB sensitivity to VCR and showed that CD24 is a potential target for improving chemotherapeutic sensitivity and RB patient outcomes.

MiR-486-3p inhibits the proliferation, migration and invasion of retinoblastoma cells by targeting ECM1

It has been reported that miR-486-3p expression is decreased in retinoblastoma (RB) tumor tissues, however, its function in RB has been less reported. The present study aimed to explore the regulatory effects of miR-486-3p on RB cells. The expression of miR-486-3p in RB tissues and cells was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability, proliferation, apoptosis, migration and invasion ability were determined by cell counting kit-8 (CCK-8) kit, clone formation assay, flow cytometry, scratch assay and transwell, respectively. Targetscan 7.2 and dual-luciferase reporter were used to verify target genes for miR-486-3p. The expressions of apoptosis-related proteins and ECM1 were detected by Western blot. The miR-486-3p expression was decreased in RB tissues and cells. In RB cells, overexpression of miR-486-3p inhibited cell proliferation, migration and invasion, while promoted apoptosis. Moreover, overexpression of miR-486-3p decreased Bcl-2 expression, while increased the expressions of Bax and Cleaved Caspase-3 (C caspase-3). ECM1 was the target gene of miR-486-3p, and miR-486-3p inhibited the expression of ECM1. Furthermore, ECM1 partially reversed the inhibitory effect of miR-486-3p on the proliferation, migration and invasion of RB cells. MiR-486-3p inhibited the proliferation, migration and invasion of RB by down-regulating ECM1.

The Emerging Roles of miR-125b in Cancers

MicroRNAs (miRNAs) are endogenous, noncoding, single-stranded RNA molecules of 22 nucleotides in length. MiRNAs have both tumor-suppressive properties and oncogenic properties that can control critical processes in tumors. Mature miR-125b originates from miR-125b-1 and miR-125b-2 and leads to the degradation of target mRNAs or the inhibition of translation through binding to the 3′ untranslated regions (3′-UTR) of target mRNAs. Importantly, miR-125b is involved in regulating NF-κB, p53, PI3K/Akt/mTOR, ErbB2, Wnt, and another signaling pathways, thereby controlling cell proliferation, differentiation, metabolism, apoptosis, drug resistance and tumor immunity. This review aims to summarize the recent literature on the role of miR-125b in the regulation of tumorigenesis and to explore its potential clinical application in the diagnosis, prognosis and clinical treatment of tumors.

Up-regulation of DRAM2 promotes tolerance of bladder transitional cell carcinoma to gemcitabine

INTRODUCTION

Bladder transitional cell carcinoma (BTCC) is one of the most prevalent human malignant diseases. Gemcitabine is commonly applied in the treatment of BTCC while acquired gemcitabine resistance has caused a severe impediment to recovery. This study aimed to investigate the function of DRAM2 in regulating gemcitabine resistance of BTCC.

MATERIAL AND METHODS

GSE77883 was introduced to screen out the differentially expressed autophagy-related genes in T24 cells and gemcitabine-resistant T24-GEM cells. After establishing T24-GEM cells ourselves, aberrant expression of DRAM2 was detected by qRT-PCR and Western blot. After stably manipulating the expression of DRAM2 in T24 and T24-GEM cells, the changes of cell biological functions under gemcitabine treatment were compared, including cell viability, apoptosis and autophagy, using colony formation, flow cytometry and electron microscopy respectively.

RESULTS

DRAM2 was up-regulated in gemcitabine-resistant T24-GEM cells. Silencing of DRAM2 in T24-GEM cells inhibited the cell autophagy induced by treatment with gemcitabine and contributed to attenuated gemcitabine resistance. Also, overexpression of DRAM2 in T24 cells enhanced the autophagy, strengthened the chemoresistance and decreased the cell apoptosis rate under the treatment with gemcitabine.

CONCLUSIONS

Our data suggested that downregulation of DRAM2 rescued the sensitivity of T24-GEM cells to gemcitabine, providing an appropriate therapeutic target for BTCC treatment.

Non-Coding RNAs in Retinoblastoma

Retinoblastoma (Rb) is the most common ocular pediatric malignancy that arises from the retina and is caused by a mutation of the two alleles of the tumor suppressor gene, RB1. Although early detection provides the opportunity of controlling the primary tumor with effective therapies, metastatic activity is fatal. Non-coding RNAs (ncRNAs) have emerged as important modifiers of a plethora of biological mechanisms including those involved in cancer. They are classified into short and long ncRNAs according to their length. Deregulation of all these molecules has also been shown to play a critical role in Rb pathogenesis and progression. It is believed that ncRNAs can provide new insights into novel regulatory mechanisms associated with clinical pathological characteristics, facilitating the development of therapeutic alternatives for the treatment of Rb. In this review, we describe a variety of ncRNAs, which capable of regulating the most likely candidate genes involved in the tumorigenesis of Rb, could prove useful in analyzing different aspects of this cancer.

MicroRNA-98 targets HMGA2 to inhibit the development of retinoblastoma through mediating Wnt/β-catenin pathway

BACKGROUND

Recently, the incidence and mortality of retinoblastoma (RB) have gradually increased. Many studies support the pivotal role of microRNAs (miRNAs) in the pathogenesis of RB. Alternation of microRNA-98 (miR-98) expression has been detected in several cancers, excluding RB. This study was designed to assess the regulatory mechanisms of miR-98 in human RB.

METHODS

RT-qPCR and Western blot analysis were used to detect miR-98 and HMGA2 expression. The effects of miR-98 were explored using the CCK-8 and Transwell assays. Dual-luciferase reporter assay was performed to confirm the relationship between miR-98 and HMGA2.

RESULTS

In RB, downregulation of miR-98 was identified. Upregulation of miR-98 inhibited proliferation, invasion and migration of RB cells. Further, HMGA2 was confirmed as a direct target gene of miR-98. And knockdown of HMGA2 suppressed the progression of RB. Moreover, upregulation of HMGA2 reversed the suppressive effects in the development of RB. In addition, miR-98 also showed suppressive effect on EMT and Wnt/β-catenin pathway.

CONCLUSION

MiR-98 targets HMGA2 to act as a tumor suppressor in RB by mediating Wnt/β-catenin pathway.

MicroRNA-598 acts as an inhibitor in retinoblastoma through targeting E2F1 and regulating AKT pathway

Recently, microRNAs (miRNAs) receive more attention due to their role in the pathogenesis of malignancies. Retinoblastoma (RB) is the most serious and harmful malignant tumor in infants and young children with eye diseases, which often endangers the lives of children. This study was designed to determine how miR-598 is involved in RB progression. In this study, quantitative reverse transcription-polymerase chain reaction, Western blot, dual-luciferase reporter, Cell Counting Kit-8, and Transwell assays were adopted to detect miR-598 expression and function in RB. The decreased expression of miR-598 was identified in RB. Overexpression of miR-598 suppressed the viability and metastasis of RB cells. Further, E2F transcription factor 1 (E2F1) is verified as a direct target of miR-598. Furthermore, E2F1 recovered miR-598-mediated-inhibition of cell viability and metastasis in RB. In addition, miR-598 was found to promote cell apoptosis and inactivate the protein kinase B (AKT) pathway in RB. miR-598 suppressed RB cell viability and metastasis through inhibiting E2F1 and inactivating AKT pathway, which may provide a new perspective for RB treatment.

MicroRNA-129-5p suppresses proliferation, migration and invasion of retinoblastoma cells through PI3K/AKT signaling pathway by targeting PAX6

BACKGROUND

Retinoblastoma (RB) is the most common primary intraocular malignancy in children. Accumulating evidences have clarified that microRNAs (miRNAs) modulated signaling molecules by acting as oncogenes or tumor-suppressor genes in RB. Thus, in our study, we aimed to investigate the function of miR-129-5p in RB cells through PI3K/AKT signaling pathway by targeting PAX6. Two RB cell lines, Y79 and WERI-Rb-1, were selected in our study, followed by transfection of miR-129-5p inhibitor or si-PAX6 to explore the regulatory role of miR-129-5p in RB cell proliferation, invasion and migration.

MATERIAL AND METHODS

Dual-luciferase assay was used for the detection of targeting relationship between miR-129-5p and PAX6. Besides, western blot analysis was applied to detect expression of cell cycle-related factors (CDK2 and Cyclin E) and PI3K/AKT signaling pathway-related factors (p-AKT and AKT). Nude mice tumorigenesis experiment was used to evaluate the effect of miR-129a-5p on RB growth in vivo.

RESULTS

miR-129-5p was down-regulated in RB cell lines. miR-129-5p directly targeted the 3'-untranslated region of PAX6. Artificial down-regulation of miR-129-5p promoted cell proliferation, migration and invasion in RB cell lines Y79 and WERI-Rb-1, and promoted RB growth in vivo via PI3K/AKT signaling pathway, which could be reversed by transfection with silencing PAX6.

CONCLUSION

This study provides evidences that RB progression was suppressed by overexpressed miR-129-5p via direct targeting of PAX6 through PI3K/AKT signaling pathway, which may provide a molecular basis for better treatment for RB.

Non-Coding RNAs in Pediatric Solid Tumors

Pediatric solid tumors are a diverse group of extracranial solid tumors representing approximately 40% of childhood cancers. Pediatric solid tumors are believed to arise as a result of disruptions in the developmental process of precursor cells which lead them to accumulate cancerous phenotypes. In contrast to many adult tumors, pediatric tumors typically feature a low number of genetic mutations in protein-coding genes which could explain the emergence of these phenotypes. It is likely that oncogenesis occurs after a failure at many different levels of regulation. Non-coding RNAs (ncRNAs) comprise a group of functional RNA molecules that lack protein coding potential but are essential in the regulation and maintenance of many epigenetic and post-translational mechanisms. Indeed, research has accumulated a large body of evidence implicating many ncRNAs in the regulation of well-established oncogenic networks. In this review we cover a range of extracranial solid tumors which represent some of the rarer and enigmatic childhood cancers known. We focus on two major classes of ncRNAs, microRNAs and long non-coding RNAs, which are likely to play a key role in the development of these cancers and emphasize their functional contributions and molecular interactions during tumor formation.

Characterization of the cone-rod dystrophy retinal phenotype caused by novel homozygous DRAM2 mutations

Cone-rod dystrophies (CRD) are a group of Inherited Retinal Dystrophies (IRD) characterized by the primary involvement of cone photoreceptors, resulting in the degeneration of the central retina, or macula. Although there are more than 55 CRD genes, a considerable percentage of cases remain unsolved. In this context, the present study aimed to describe and characterize the phenoptype and the genetic cause of 3 CRD families from a cohort of IRD cases. Clinical evaluation in each patient was supported by a complete ophthalmological examination, including visual acuity measurement, fundus retinography, fundus autofluorescence imaging, optical coherence tomography and full-field electroretinography. Molecular diagnoses were performed by whole exome sequencing analyzing a group of 279 IRD genes, and cosegregation of the identified pathogenic variants was confirmed by Sanger sequencing. Three novel homozygous mutations in the autophagy gene DRAM2 were identified as the molecular cause of disease in the three families: c.518-1G>A, c.628_629insAG and c.693+2T>A. Clinical data revealed that the 3 patients presented a shared CRD phenotype with adult-onset macular involvement and later peripheral degeneration, although the age of onset, evolution and severity were variable. In order to characterize the transcription effects of these variants, mRNA expression studies were performed. The results showed alterations in the DRAM2 transcription, including alternative splicing forms and lower levels of mRNA, which correlated with the phenotypic variability observed between patients. For instance, frameshift mutations were related to a less severe phenotype, with circumscribed mid-peripheral involvement, and lower levels of mRNA, suggesting an activation of the nonsense-mediated decay (NMD) pathway; while a more severe and widespread retinal degeneration was associated to the inframe alternative splicing variant reported, possibly due to a malfunctioning or toxicity of the resulting protein. Following these findings, DRAM2 expression was assessed in several human tissues by semi-quantitative RT-PCR and two isoforms were detected ubiquitously, yet with a singular tissue-specific pattern in retina and brain. Altogether, although the unique retinal phenotype described did not correlate with the ubiquitous expression, the retinal-specific expression and the essential role of autophagy in the photoreceptor survival could be key arguments to explain this particular DRAM2 phenotype.

p53, stem cell biology and childhood blastomas

PURPOSE OF REVIEW

Childhood blastomas, unlike adult cancers, originate from developing organs in which molecular and cellular features exhibit differentiation arrest and embryonic characteristics. Conventional cancer therapies, which rely on the generalized cytotoxic effect on rapidly dividing cells, may damage delicate organs in young children, leading to multiple late effects. Deep understanding of the biology of embryonal cancers is crucial in reshaping the cancer treatment paradigm for children.

RECENT FINDINGS

p53 plays a major physiological role in embryonic development, by controlling cell proliferation, differentiation and responses to cellular stress. Tumor suppressor function of p53 is commonly lost in adult cancers through genetic alterations. However, both somatic and germline p53 mutations are rare in childhood blastomas, suggesting that in these cancers, p53 may be inactivated through other mechanisms than mutation. In this review, we summarize current knowledge about p53 pathway inactivation in childhood blastomas (specifically neuroblastoma, retinoblastoma and Wilms' tumor) through various upstream mechanisms. Laboratory evidence and clinical trials of targeted therapies specific to exploiting p53 upstream regulators are discussed.

SUMMARY

Despite the low rate of inherent TP53 mutations, p53 pathway inactivation is a common denominator in childhood blastomas. Exploiting p53 and its regulators is likely to translate into more effective targeted therapies with minimal late effects for children. (see Video Abstract, Supplemental Digital Content 1, http://links.lww.com/COON/A23).

Expression Profiling Analysis Reveals Key MicroRNA-mRNA Interactions in Early Retinal Degeneration in Retinitis Pigmentosa

Purpose

The aim of this study was to identify differentially expressed microRNAs (miRNAs) that might play an important role in the etiology of retinal degeneration in a genetic mouse model of retinitis pigmentosa (rd10 mice) at initial stages of the disease.

Methods

miRNAs–mRNA interaction networks were generated for analysis of biological pathways involved in retinal degeneration.

Results

Of more than 1900 miRNAs analyzed, we selected 19 miRNAs on the basis of (1) a significant differential expression in rd10 retinas compared with control samples and (2) an inverse expression relationship with predicted mRNA targets involved in biological pathways relevant to retinal biology and/or degeneration. Seven of the selected miRNAs have been associated with retinal dystrophies, whereas, to our knowledge, nine have not been previously linked to any disease.

Conclusions

This study contributes to our understanding of the etiology and progression of retinal degeneration.

DRAM2 acts as an oncogene in non-small cell lung cancer and suppresses the expression of p53

BACKGROUND

Damage-regulated autophagy modulator 2(DRAM2) is associated with autophagy processes. However, the role of DRAM2 in the progression of human neoplasms is still unknown. Here, we show that DRAM2 may act as an oncogenic regulator in non-small cell lung cancer (NSCLC).

METHODS

Tumor specimens from 259 NSCLC patients were collected and analyzed. Transwell migration, cell cycle analysis, MTT and colony formation assays were performed to determine the effect of DRAM2 overexpression and knockdown on NSCLC-cell migration and proliferation. Western blotting confirmed the expression of DRAM2, p53, and the other involved proteins.

RESULTS

DRAM2 was preferentially upregulated in NSCLC tissues and higher expression of DRAM2 in NSCLC correlated with tumor node metastases stage and lymph node metastasis. Additionally, DRAM2 overexpression promoted cell metastasis and proliferation in vitro, while knockdown of DRAM2 expression yielded opposite result. Furthermore, DRAM2 overexpression increased the expression of proteins RAC1, RHOA, RHOC, ROCK1, and decreased RHOB expression, all of which are cell migration factors. DRAM2 overexpression also increased proteins CDK4, CyclinD3, and decreased p27 expression, all of which are cell cycle-related factors. Consistently knocked down DRAM2 had the opposite effect. We also found that DRAM2 expression was negatively correlated to p53 expression. Knockdown of DRAM2 caused an increase of p53 and p21 expression, and overexpression of p53 caused a decrease of DRAM2 expression. Finally, absence of p53 did not influence the function of DRAM2 in NSCLC, but overexpression of p53 repressed its function.

CONCLUSIONS

DRAM2 plays an oncogenic role in NSCLC via regulating p53 expression. Therefore, DRAM2 may act as an oncogene in NSCLC and could serve as a prognostic factor and potential target for NSCLC treatment.

Therapeutic microRNAs in human cancer

MicroRNAs (miRNAs) are RNA molecules at about 22 nucleotide in length that are non-coding, which regulate gene expression in the post-transcriptional level by performing degradation or blocks translation of the target mRNA. It is known that they play roles in mechanisms such as metabolic regulation, embryogenesis, organogenesis, differentiation and growth control by providing post-transcriptional regulation of gene expression. With these properties, miRNAs play important roles in the regulation of biological processes such as proliferation, differentiation, apoptosis, drug resistance mechanisms in eukaryotic cells. In addition, there are miRNAs that can be used for cancer therapy. Tumor cells and tumor microenvironment have different miRNA expression profiles. Some miRNAs are known to play a role in the onset and progression of the tumor. miRNAs with oncogenic or tumor suppressive activity specific to different cancer types are still being investigated. This review summarizes the role of miRNAs in tumorigenesis, therapeutic strategies in human cancer and current studies.

MicroRNA-361-3p regulates retinoblastoma cell proliferation and stemness by targeting hedgehog signaling

Retinoblastoma (RB) is the most common type of intraocular malignancy in children. During RB oncogenesis, sonic hedgehog (SHH) is commonly differentially expressed. Additionally, microRNAs (miRs) are known to serve crucial roles as oncogenes or tumor suppressors. Specifically, miR-361-3p has been revealed to serve a vital role in cutaneous squamous cell carcinoma, cervical cancer, prostate cancer, colorectal cancer, gastric cancer, hepatocellular carcinoma, breast cancer and lung cancer. However, the role of miR-361-3p in RB and the potential molecular mechanisms involved remain unknown. Therefore, the current study aimed to determine the involvement of miR-361-3p in the development of RB by targeting SHH signaling. In the present study, miR-361-3p expression levels in RB tissue and serum samples obtained from 10 patients with RB, normal retinal tissue and serum samples obtained from 10 healthy controls, and two human RB cell lines (Y79 and Weri-Rb-1) were determined using reverse transcription-quantitative polymerase chain reaction. In addition, a cell counting kit-8 assay, a cell transfection assay, a MTT assay, western blotting, a tumor sphere formation assay and a luciferase assay were used to assess the expression, function and molecular mechanism of miR-361-3p in human RB. It was demonstrated that miR-361-3p was significantly downregulated in RB tissues, RB serum and RB cell lines compared with normal retinal tissues and normal serum. The ectopic expression of miR-361-3p decreased RB cell proliferation and stemness. Furthermore, GLI1 and GLI3 were verified as potential direct targets of miR-361-3p. miR-361-3p was also revealed to exhibit a negative correlation with GLI1/3 expression in RB samples. Taken together, the results indicate that miR-361-3p functions as a tumor suppressor in the carcinogenesis and progression of RB by targeting SHH signaling. Thus, miR-361-3p should be further assessed as a potential therapeutic target for RB treatment.

MicroRNA-106b promotes the proliferation, migration and invasion of retinoblastoma cells by inhibiting the expression of ZBTB4 protein

The present study investigated the function of microRNA (miR)-106b in the proliferation, migration and invasion of retinoblastoma (RB) cells, and aimed to elucidate the underlying mechanism. A total of 56 patients with RB were enrolled in the present study. The expression of miR-106b in RB tissues was measured by reverse transcription quantitative polymerase chain reaction. After transfection with miR-106b mimics or miR-106b inhibitor, a Cell-Counting kit-8 assay was used to determine the proliferation of WERI-Rb-1 cells and a Transwell assay was employed to measure the migration and invasion of the cells. Western blot analysis was performed to determine the expression of zinc finger and BTB domain containing 4 (ZBTB4) protein. By silencing or overexpression of ZBTB4 protein, the biological functions of ZBTB4 in WERI-Rb-1 cells were studied. A dual luciferase reporter assay was performed to test whether ZBTB4 was a target gene of miR-106b. The expression of miR-106b in RB tissues was elevated and closely associated with the severity of the disease. Overexpression of miR-106b increased but inhibition of miR-106b expression decreased the proliferation, migration and invasion abilities of WERI-Rb-1 cells. In addition, overexpression of miR-106b decreased but inhibition of miR-106b expression increased ZBTB4 protein expression in WERI-Rb-1 cells. Similarly, overexpression of ZBTB4 reduced but inhibition of ZBTB4 expression promoted the proliferation, migration and invasion of WERI-Rb-1 cells. Finally, miR-106b regulated the expression of ZBTB4 by binding to the 3'-untranslated region of the ZBTB4 gene. The present study demonstrated that increased expression of miR-106b in RB tissues is positively associated with the metastasis and differentiation of RB cells. As an oncogene, miR-106b promotes the proliferation, migration and invasion of WERI-Rb-1 cells by inhibiting the expression of ZBTB4 protein.

The down-regulation of microRNA-137 contributes to the up-regulation of retinoblastoma cell proliferation and invasion by regulating COX-2/PGE2 signaling

MicroRNA-137 (miR-137) plays an important role in the development and progression of many types of human cancers; however, the role of miR-137 in retinoblastoma (RB) remains unclear. In this study, we aimed to investigate the functional significance and molecular mechanisms of miR-137 in RB. We reported that miR-137 was frequently down-regulated in RB tissues and cell lines. The overexpression of miR-137 inhibited RB cell proliferation and invasion, while the suppression of miR-137 promoted RB cell proliferation and invasion. Bioinformatic analysis predicted that cyclooxygenase-2 (COX-2) was a potential target gene of miR-137, which was validated by a dual-luciferase reporter assay. Moreover, our results showed that miR-137 negatively regulated the expression of COX-2 and the production of prostaglandin E2 (PGE2) in RB cells. The knockdown of COX-2 suppressed the proliferation and invasion of RB cells as well as the production of PGE2. The overexpression of COX-2 significantly reversed the inhibitory effect of miR-137 overexpression on RB cell proliferation and invasion. Taken together, these results suggest that miR-137 suppresses the proliferation and invasion of RB cells by targeting COX-2/PGE2. Our study reveals a tumor suppressive role of miR-137 in the progression of RB and suggests miR-137 as a potentially effective therapeutic target for the treatment of RB.

Downregulation of microRNA‑198 suppresses cell proliferation and invasion in retinoblastoma by directly targeting PTEN

A number of studies have highlighted that aberrantly expressed microRNAs (miRNAs/miRs) serve crucial roles in the tumorigenesis and tumor development of retinoblastoma (RB). Hence, a full investigation of the biological roles and regulatory mechanisms of miRNAs in RB may provide novel therapeutic targets for patients with this malignancy. miR‑198 is frequently abnormally expressed in various types of human cancers. However, the expression level, biological roles and underlying mechanisms of miR‑198 in RB remain to be elucidated. In the present study, miR‑198 expression was upregulated in RB tissues and cell lines. Silencing of miR‑198 attenuated cell proliferation and invasion in RB. In addition, phosphatase and tensin homolog deleted on chromosome ten (PTEN) was predicted as a potential target of miR‑198 using bioinformatics analysis. Subsequent luciferase reporter assay indicated that the 3'‑untranslated region of PTEN can be directly targeted by miR‑198. Furthermore, miR‑198 inhibition increased the PTEN expression at the mRNA and protein levels in RB cells. In addition, PTEN mRNA expression was downregulated in RB tissues, and this downregulation was inversely associated with the expression level of miR‑198. PTEN knockdown rescued the inhibitory effects of miR‑198 underexpression on cell proliferation and invasion in RB. Notably, the downregulation of miR‑198 inactivated the phosphoinositide 3‑kinase (PI3K)/protein kinase B (AKT) signaling pathway in RB. These results demonstrated that miR‑198 may serve oncogenic roles in RB by directly targeting PTEN and regulating the PI3K/AKT signaling pathway. Hence, miR‑198 may be a promising therapeutic target for patients with RB.

MicroRNAs in retinoblastoma: Potential diagnostic and therapeutic biomarkers

Retinoblastoma (Rb) is known as one of important childhood malignancies which due to inactivation of the RB gene (tumor suppressor gene in various patients). The early detection of Rb could provide better treatment for Rb patients. Imaging techniques (e.g., MRI and CT) are known as one of effective diagnosis approaches for detection of patients with Rb. It has been shown that utilization of imaging techniques is associated with some limitations. Hence, identification of new diagnosis approaches might provide a better treatment for Rb patients. Identification of new biomarkers could contribute to better understanding of pathogenesis events involved in Rb and provide new insights into design better treatment approaches for these patients. Among the various biomarkers, microRNAs (miRNAs) have emerged as attractive tools for Rb detection. miRNAs are one classes of small non-coding RNAs which could anticipate in a variety of biological process via targeting sequence of cellular and molecular pathways. Deregulations of these molecules are associated with cancerous condition. Multiple lines of evidence indicated that deregulation of various miRNAs involved in various stages of Rb. Here, we summarized a variety of tissue-specific and circulating miRNAs involved in Rb pathogenesis which could be used as diagnostic, prognostic, and therapeutic biomarkers in Rb patients.

Exosomes derived from human umbilical cord mesenchymal stem cells protect against cisplatin-induced ovarian granulosa cell stress and apoptosis in vitro

Human umbilical cord mesenchymal stem cells (huMSCs) can treat primary ovarian insufficiency (POI) related to ovarian granulosa cell (OGC) apoptosis caused by cisplatin chemotherapy. Exosomes are a class of membranous vesicles with diameters of 30–200 nm that are constitutively released by eukaryotic cells. Exosomes mediate local cell-to-cell communication by transferring microRNAs and proteins. In the present study, we demonstrated the effects of exosomes derived from huMSCs (huMSC-EXOs) on a cisplatin-induced OGC model in vitro and discussed the preliminary mechanisms involved in these effects. We successfully extracted huMSC-EXOs from huMSC culture supernatant and observed the effective uptake of exosomes by cells with fluorescent staining. Using flow cytometry (with annexin-V/PI labelling), we found that huMSC-EXOs increased the number of living cells. Western blotting showed that the expression of Bcl-2 and caspase-3 were upregulated, whilst the expression of Bax, cleaved caspase-3 and cleaved PARP were downregulated to protect OGCs. These results suggest that huMSC-EXOs can be used to prevent and treat chemotherapy-induced OGC apoptosis in vitro. Therefore, this work provides insight and further evidence of stem cell function and indicates that huMSC-EXOs protect OGCs from cisplatin-induced injury in vitro.