A Simplified System to Express Circularized Inhibitors of miRNA for Stable and Potent Suppression of miRNA Functions

Dual Roles of miR-10a-5p and miR-10b-5p as Tumor Suppressors and Oncogenes in Diverse Cancers

Cancer is a complex genetic disorder characterized by abnormalities in both coding and regulatory non-coding RNAs. microRNAs (miRNAs) are key regulatory non-coding RNAs that modulate cancer development, functioning as both tumor suppressors and oncogenes. miRNAs play critical roles in cancer progression, influencing key processes such as initiation, promotion, and metastasis. They exert their effects by targeting tumor suppressor genes, thereby facilitating cancer progression, while also inhibiting oncogenes to prevent further disease advancement. The miR-10 family, particularly miR-10a-5p and miR-10b-5p (miR-10a/b-5p), is notably involved in cancer progression. Intriguingly, their functions can differ across different cancers, sometimes promoting and at other times suppressing tumor growth depending on the cancer type and target genes. This review explores the dual roles of miR-10a/b-5p as tumor-suppressive miRNAs (TSmiRs) or oncogenic miRNAs (oncomiRs) in various cancers by examining their molecular and cellular mechanisms and their impact on the tumor microenvironment. Furthermore, we discuss the potential of miR-10a/b-5p as therapeutic targets, emphasizing miRNA-based strategies for cancer treatment. The insights discussed in this review aim to advance our understanding of miR-10a/b-5p's roles in tumor biology and their application in developing innovative cancer therapies.

GAPDH suppresses adenovirus-induced oxidative stress and enables a superfast production of recombinant adenovirus

Recombinant adenovirus (rAdV) is a commonly used vector system for gene transfer. Efficient initial packaging and subsequent production of rAdV remains time-consuming and labor-intensive, possibly attributable to rAdV infection-associated oxidative stress and reactive oxygen species (ROS) production. Here, we show that exogenous GAPDH expression mitigates adenovirus-induced ROS-associated apoptosis in HEK293 cells, and expedites adenovirus production. By stably overexpressing GAPDH in HEK293 (293G) and 293pTP (293GP) cells, respectively, we demonstrated that rAdV-induced ROS production and cell apoptosis were significantly suppressed in 293G and 293GP cells. Transfection of 293G cells with adenoviral plasmid pAd-G2Luc yielded much higher titers of Ad-G2Luc at day 7 than that in HEK293 cells. Similarly, Ad-G2Luc was amplified more efficiently in 293G than in HEK293 cells. We further showed that transfection of 293GP cells with pAd-G2Luc produced much higher titers of Ad-G2Luc at day 5 than that of 293pTP cells. 293GP cells amplified the Ad-G2Luc much more efficiently than 293pTP cells, indicating that exogenous GAPDH can further augment pTP-enhanced adenovirus production. These results demonstrate that exogenous GAPDH can effectively suppress adenovirus-induced ROS and thus accelerate adenovirus production. Therefore, the engineered 293GP cells represent a superfast rAdV production system for adenovirus-based gene transfer and gene therapy.

Advanced approaches of the use of circRNAs as a replacement for cancer therapy

Cancer is a broad name for a group of diseases in which abnormal cells grow out of control and are characterized by their complexity and recurrence. Although there has been progress in cancer therapy with the entry of precision medicine and immunotherapy, cancer incidence rates have increased globally. Non-coding RNAs in the form of circular RNAs (circRNAs) play crucial roles in the pathogenesis, clinical diagnosis, and therapy of different diseases, including cancer. According to recent studies, circRNAs appear to serve as accurate indicators and therapeutic targets for cancer treatment. However, circRNAs are promising candidates for cutting-edge cancer therapy because of their distinctive circular structure, stability, and wide range of capabilities; many challenges persist that decrease the applications of circRNA-based cancer therapeutics. Here, we explore the roles of circRNAs as a replacement for cancer therapy, highlight the main challenges facing circRNA-based cancer therapies, and discuss the key strategies to overcome these challenges to improve advanced innovative therapies based on circRNAs with long-term health effects.

Inhibiting miR-618 Promotes Keratinocytes Proliferation and Migration to Enhance Wound Healing in Mice

The delay in wound healing caused by chronic wounds or pathological scars is a pressing issue in clinical practice, imposing significant economic and psychological burdens on patients. In particular, with the aging of the population and the increasing incidence of diseases such as diabetes, impaired wound healing is one of the growing health problems. MicroRNA (miRNA) plays a crucial role in wound healing and regulates various biological processes. Our results show that miR-618 was significantly upregulated during the inflammatory phase of wound healing.Subsequently, miR-618 promotes the secretion of pro-inflammatory cytokines and regulates the proliferation and migration of keratinocytes. Mechanistically, miR-618 binds to the target gene-Atp11b and inhibits the PI3K-Akt signaling pathway, inhibiting the epithelial-mesenchymal transition (EMT) of keratinocytes. In addition, the PI3K-Akt signaling pathway induces the enrichment of nuclear miR-618, and miR-618 binds to the promoter of Lin7a to regulate gene transcription. Intradermal injection of miR-618 antagomir around full-thickness wounds in peridermal mice effectively accelerates wound closure compared to control. In conclusion, miR-618 antagomir can be a potential therapeutic agent for wound healing.

Circular Single-Stranded DNA: Discovery, Biological Effects, and Applications

The field of nucleic acid therapeutics has witnessed a significant surge in recent times, as evidenced by the increasing number of approved genetic drugs. However, current platform technologies containing plasmids, lipid nanoparticle-mRNAs, and adeno-associated virus vectors encounter various limitations and challenges. Thus, we are devoted to finding a novel nucleic acid vector and have directed our efforts toward investigating circular single-stranded DNA (CssDNA), an ancient form of nucleic acid. CssDNAs are ubiquitous, but generally ignored. Accumulating evidence suggests that CssDNAs possess exceptional properties as nucleic acid vectors, exhibiting great potential for clinical applications in genetic disorders, gene editing, and immune cell therapy. Here, we comprehensively review the discovery and biological effects of CssDNAs as well as their applications in the field of biomedical research for the first time. Undoubtedly, as an ancient form of DNA, CssDNA holds immense potential and promises novel insights for biomedical research.

Circular RNA and intervertebral disc degeneration: unravelling mechanisms and implications

Low back pain (LBP) is a major public health problem worldwide and a significant health and economic burden. Intervertebral disc degeneration (IDD) is the reason for LBP. However, we have not identified effective therapeutic strategies to address this challenge. With accumulating knowledge on the role of circular RNAs in the pathogenesis of IDD, we realised that circular RNAs (circRNAs) may have tremendous therapeutic potential and clinical application prospects in this field. This review presents an overview of the current understanding of characteristics, classification, biogenesis, and function of circRNAs and summarises the protective and detrimental circRNAs involved in the intervertebral disc that have been studied thus far. This review is aimed to help researchers better understand the regulatory role of circRNAs in the progression of IDD, reveal their clinical therapeutic potential, and provide a theoretical basis for the prevention and targeted treatment of IDD.

Niclosamide (NA) overcomes cisplatin resistance in human ovarian cancer

Ovarian cancer (OC) is one of the most lethal malignancies of the female reproductive system. OC patients are usually diagnosed at advanced stages due to the lack of early diagnosis. The standard treatment for OC includes a combination of debulking surgery and platinum-taxane chemotherapy, while several targeted therapies have recently been approved for maintenance treatment. The vast majority of OC patients relapse with chemoresistant tumors after an initial response. Thus, there is an unmet clinical need to develop new therapeutic agents to overcome the chemoresistance of OC. The anti-parasite agent niclosamide (NA) has been repurposed as an anti-cancer agent and exerts potent anti-cancer activities in human cancers including OC. Here, we investigated whether NA could be repurposed as a therapeutic agent to overcome cisplatin-resistant (CR) in human OC cells. To this end, we first established two CR lines SKOV3CR and OVCAR8CR that exhibit the essential biological characteristics of cisplatin resistance in human cancer. We showed that NA inhibited cell proliferation, suppressed cell migration, and induced cell apoptosis in both CR lines at a low micromole range. Mechanistically, NA inhibited multiple cancer-related pathways including AP1, ELK/SRF, HIF1, and TCF/LEF, in SKOV3CR and OVCAR8CR cells. NA was further shown to effectively inhibit xenograft tumor growth of SKOV3CR cells. Collectively, our findings strongly suggest that NA may be repurposed as an efficacious agent to combat cisplatin resistance in chemoresistant human OC, and further clinical trials are highly warranted.

Ageing at Molecular Level: Role of MicroRNAs

The progression of age triggers a vast number of diseases including cardiovascular, cancer, and neurodegenerative disorders. Regardless of our plentiful knowledge about age-related diseases, little is understood about molecular pathways that associate the ageing process with various diseases. Several cellular events like senescence, telomere dysfunction, alterations in protein processing, and regulation of gene expression are common between ageing and associated diseases. Accumulating information on the role of microRNAs (miRNAs) suggests targeting miRNAs can aid our understanding of the interplay between ageing and associated diseases. In the present chapter, we have attempted to explore the information available on the role of miRNAs in ageing of various tissues/organs and diseases and understand the molecular mechanism of ageing.

Modeling lung diseases using reversibly immortalized mouse pulmonary alveolar type 2 cells (imPAC2)

BACKGROUND

A healthy alveolar epithelium is critical to the gas exchange function of the lungs. As the major cell type of alveolar epithelium, alveolar type 2 (AT2) cells play a critical role in maintaining pulmonary homeostasis by serving as alveolar progenitors during lung injury, inflammation, and repair. Dysregulation of AT2 cells may lead to the development of acute and chronic lung diseases and cancer. The lack of clinically relevant AT2 cell models hampers our ability to understand pulmonary diseases. Here, we sought to establish reversibly immortalized mouse pulmonary alveolar type 2 cells (imPAC2) and investigate their potential in forming alveolar organoids to model pulmonary diseases.

METHODS

Primary mouse pulmonary alveolar cells (mPACs) were isolated and immortalized with a retroviral expression of SV40 Large T antigen (LTA). Cell proliferation and survival was assessed by crystal violet staining and WST-1 assays. Marker gene expression was assessed by qPCR, Western blotting, and/or immunostaining. Alveolar organoids were generated by using matrigel. Ad-TGF-β1 was used to transiently express TGF-β1. Stable silencing β-catenin or overexpression of mutant KRAS and TP53 was accomplished by using retroviral vectors. Subcutaneous cell implantations were carried out in athymic nude mice. The retrieved tissue masses were subjected to H & E histologic evaluation.

RESULTS

We immortalized primary mPACs with SV40 LTA to yield the imPACs that were non-tumorigenic and maintained long-term proliferative activity that was reversible by FLP-mediated removal of SV40 LTA. The EpCAM+ AT2-enriched subpopulation (i.e., imPAC2) was sorted out from the imPACs, and was shown to express AT2 markers and form alveolar organoids. Functionally, silencing β-catenin decreased the expression of AT2 markers in imPAC2 cells, while TGF-β1 induced fibrosis-like response by regulating the expression of epithelial-mesenchymal transition markers in the imPAC2 cells. Lastly, concurrent expression of oncogenic KRAS and mutant TP53 rendered the imPAC2 cells a tumor-like phenotype and activated lung cancer-associated pathways. Collectively, our results suggest that the imPAC2 cells may faithfully represent AT2 populations that can be further explored to model pulmonary diseases.

Elucidating miRNA Function in Cancer Biology via the Molecular Genetics' Toolbox

Micro-RNA (miRNAs) are short non-coding RNAs of about 18-20 nucleotides in length and are implicated in many cellular processes including proliferation, development, differentiation, apoptosis and cell signaling. Furthermore, it is well known that miRNA expression is frequently dysregulated in many cancers. Therefore, this review will highlight the various mechanisms by which microRNAs are dysregulated in cancer. Further highlights include the abundance of molecular genetics tools that are currently available to study miRNA function as well as their advantages and disadvantages with a special focus on various CRISPR/Cas systems This review provides general workflows and some practical considerations when studying miRNA function thus enabling researchers to make informed decisions in regards to the appropriate molecular genetics tool to be utilized for their experiments.

Reversibly immortalized keratinocytes (iKera) facilitate re-epithelization and skin wound healing: Potential applications in cell-based skin tissue engineering

Skin injury is repaired through a multi-phase wound healing process of tissue granulation and re-epithelialization. Any failure in the healing process may lead to chronic non-healing wounds or abnormal scar formation. Although significant progress has been made in developing novel scaffolds and/or cell-based therapeutic strategies to promote wound healing, effective management of large chronic skin wounds remains a clinical challenge. Keratinocytes are critical to re-epithelialization and wound healing. Here, we investigated whether exogenous keratinocytes, in combination with a citrate-based scaffold, enhanced skin wound healing. We first established reversibly immortalized mouse keratinocytes (iKera), and confirmed that the iKera cells expressed keratinocyte markers, and were responsive to UVB treatment, and were non-tumorigenic. In a proof-of-principle experiment, we demonstrated that iKera cells embedded in citrate-based scaffold PPCN provided more effective re-epithelialization and cutaneous wound healing than that of either PPCN or iKera cells alone, in a mouse skin wound model. Thus, these results demonstrate that iKera cells may serve as a valuable skin epithelial source when, combining with appropriate biocompatible scaffolds, to investigate cutaneous wound healing and skin regeneration.

Single-stranded circular DNA theranostics

The past decade has witnessed the blossom of nucleic acid therapeutics and diagnostics (theranostics). Unlike conventional small molecule medicines or protein biologics, nucleic acid theranostics have characteristic features such as the intrinsic ability as “information drugs” to code and execute genetic and theranostic information, ready programmability for nucleic acid engineering, intrinsic stimulatory or regulatory immunomodulation, versatile functionalities, and easy conformational recovery upon thermal or chemical denaturation. Single-stranded circular DNA (circDNA) are a class of single-stranded DNAs (ssDNA) featured with their covalently-closed topology. In addition to the basic advantages of nucleic acids-based materials, such as low cost, biocompatibility, and simplicity of chemical modification, the lack of terminals in circDNA prevents exonuclease degradation, resulting in enhanced biostability relative to the corresponding linear ssDNA. circDNA has been explored for versatile theranostic applications. For instance, circDNA has been extensively studied as templates for bioanalytical signal amplification and the synthesis of nano-/micro-/macro- biomaterials via rolling circle amplification (RCA) and rolling circle transcription (RCT) technologies. circDNA has also been commonly used as the scaffolds for the self-assembly of versatile DNA origami. Finally, circDNA has been implemented as theranostic aptamers, miRNA inhibitors, as well as clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins (CRISPR-Cas) gene editing donors. In this review article, we will discuss the chemistry, characteristic properties, and the theranostic applications of circDNA (excluding double-stranded circular DNA such as plasmids); we will also envision the challenges and opportunities in this research field.

Circ_0006768 upregulation attenuates oxygen-glucose deprivation/reoxygenation-induced human brain microvascular endothelial cell injuries by upregulating VEZF1 via miR-222-3p inhibition

Circular RNAs (circRNAs) have been widely implicated in multiple diseases, including ischemic stroke. This study aimed to explore the function and functional mechanism of circ_0006768 in oxygen-glucose deprivation/reoxygenation (OGD/R)-induced brain injury models of ischemic stroke. Human brain microvascular endothelial cells (HBMECs) were induced by OGD/R to mimic ischemic stroke models in vitro. The expression of circ_0006768, microRNA-222-3p (miR-222-3p) and vascular endothelial zinc finger 1 (VEZF1) was detected by quantitative real-time PCR (qPCR). Cell viability, angiogenesis ability and cell migration were assessed by cell counting kit-8 (CCK-8) assay, tube formation assay and wound healing assay, respectively. The releases of pro-inflammatory factors were determined by commercial enzyme-linked immunosorbent assay (ELISA) kits. The protein levels of vascular endothelial growth factor A (VEGFA), N-cadherin and VEZF1 were detected by western blot. The putative relationship between miR-222-3p and circ_0006768 or VEZF1 was validated by dual-luciferase reporter assay, RNA Immunoprecipitation (RIP) assay and pull-down assay. Circ_0006768 was poorly expressed in ischemic stroke plasma and OGD/R-induced HBMECs. OGD/R inhibited cell viability, angiogenesis and cell migration and promoted the releases of pro-inflammatory factors, while circ_0006768 overexpression or miR-222-3p inhibition partially abolished the effects of OGD/R. MiR-222-3p was targeted by circ_0006768, and VEZF1 was a target of miR-222-3p. Circ_0006768 enriched the expression of VEZF1 via mediating miR-222-3p inhibition. Rescue experiments presented that the effects of circ_0006768 overexpression were reversed by miR-222-3p restoration or VEZF1 knockdown. Circ_0006768 overexpression attenuates OGD/R-induced HBMEC injuries by upregulating VEZF1 via miR-222-3p inhibition.

Preclinical Imaging Evaluation of miRNAs' Delivery and Effects in Breast Cancer Mouse Models: A Systematic Review

BACKGROUND

We have conducted a systematic review focusing on the advancements in preclinical molecular imaging to study the delivery and therapeutic efficacy of miRNAs in mouse models of breast cancer.

METHODS

A systematic review of English articles published in peer-reviewed journals using PubMed, EMBASE, BIOSIS™ and Scopus was performed. Search terms included breast cancer, mouse, mice, microRNA(s) and miRNA(s).

RESULTS

From a total of 2073 records, our final data extraction was from 114 manuscripts. The most frequently used murine genetic background was Balb/C (46.7%). The most frequently used model was the IV metastatic model (46.8%), which was obtained via intravenous injection (68.9%) in the tail vein. Bioluminescence was the most used frequently used tool (64%), and was used as a surrogate for tumor growth for efficacy treatment or for the evaluation of tumorigenicity in miRNA-transfected cells (29.9%); for tracking, evaluation of engraftment and for response to therapy in metastatic models (50.6%).

CONCLUSIONS

This review provides a systematic and focused analysis of all the information available and related to the imaging protocols with which to test miRNA therapy in an in vivo mice model of breast cancer, and has the purpose of providing an important tool to suggest the best preclinical imaging protocol based on available evidence.

Argonaute (AGO) proteins play an essential role in mediating BMP9-induced osteogenic signaling in mesenchymal stem cells (MSCs)

As multipotent progenitor cells, mesenchymal stem cells (MSCs) can renew themselves and give rise to multiple lineages including osteoblastic, chondrogenic and adipogenic lineages. It's previously shown that BMP9 is the most potent BMP and induces osteogenic and adipogenic differentiation of MSCs. However, the molecular mechanism through which BMP9 regulates MSC differentiation remains poorly understood. Emerging evidence indicates that noncoding RNAs, especially microRNAs, may play important roles in regulating MSC differentiation and bone formation. As highly conserved RNA binding proteins, Argonaute (AGO) proteins are essential components of the multi-protein RNA-induced silencing complexes (RISCs), which are critical for small RNA biogenesis. Here, we investigate possible roles of AGO proteins in BMP9-induced lineage-specific differentiation of MSCs. We first found that BMP9 up-regulated the expression of Ago1, Ago2 and Ago3 in MSCs. By engineering multiplex siRNA vectors that express multiple siRNAs targeting individual Ago genes or all four Ago genes, we found that silencing individual Ago expression led to a decrease in BMP9-induced early osteogenic marker alkaline phosphatase (ALP) activity in MSCs. Furthermore, we demonstrated that simultaneously silencing all four Ago genes significantly diminished BMP9-induced osteogenic and adipogenic differentiation of MSCs and matrix mineralization, and ectopic bone formation. Collectively, our findings strongly indicate that AGO proteins and associated small RNA biogenesis pathway play an essential role in mediating BMP9-induced osteogenic differentiation of MSCs.

Modeling colorectal tumorigenesis using the organoids derived from conditionally immortalized mouse intestinal crypt cells (ciMICs)

Intestinal cancers are developed from intestinal epithelial stem cells (ISCs) in intestinal crypts through a multi-step process involved in genetic mutations of oncogenes and tumor suppressor genes. ISCs play a key role in maintaining the homeostasis of gut epithelium. In 2009, Sato et al established a three-dimensional culture system, which mimicked the niche microenvironment by employing the niche factors, and successfully grew crypt ISCs into organoids or Mini-guts in vitro. Since then, the intestinal organoid technology has been used to delineate cellular signaling in ISC biology. However, the cultured organoids consist of heterogeneous cell populations, and it was technically challenging to introduce genomic changes into three-dimensional organoids. Thus, there was a technical necessity to develop a two-dimensional ISC culture system for effective genomic manipulations. In this study, we established a conditionally immortalized mouse intestinal crypt (ciMIC) cell line by using a piggyBac transposon-based SV40 T antigen expression system. We showed that the ciMICs maintained long-term proliferative activity under two-dimensional niche factor-containing culture condition, retained the biological characteristics of intestinal epithelial stem cells, and could form intestinal organoids in three-dimensional culture. While in vivo cell implantation tests indicated that the ciMICs were non-tumorigenic, the ciMICs overexpressing oncogenic β-catenin and/or KRAS exhibited high proliferative activity and developed intestinal adenoma-like pathological features in vivo. Collectively, these findings strongly suggested that the engineered ciMICs should be used as a valuable tool cell line to dissect the genetic and/or epigenetic underpinnings of intestinal tumorigenesis.

MicroRNA as an Important Target for Anticancer Drug Development

Cancer has become the second greatest cause of death worldwide. Although there are several different classes of anticancer drugs that are available in clinic, some tough issues like side-effects and low efficacy still need to dissolve. Therefore, there remains an urgent need to discover and develop more effective anticancer drugs. MicroRNAs (miRNAs) are a class of small endogenous non-coding RNAs that regulate gene expression by inhibiting mRNA translation or reducing the stability of mRNA. An abnormal miRNA expression profile was found to exist widely in cancer cell, which induces limitless replicative potential and evading apoptosis. MiRNAs function as oncogenes (oncomiRs) or tumor suppressors during tumor development and progression. It was shown that regulation of specific miRNA alterations using miRNA mimics or antagomirs can normalize the gene regulatory network and signaling pathways, and reverse the phenotypes in cancer cells. The miRNA hence provides an attractive target for anticancer drug development. In this review, we will summarize the latest publications on the role of miRNA in anticancer therapeutics and briefly describe the relationship between abnormal miRNAs and tumorigenesis. The potential of miRNA-based therapeutics for anticancer treatment has been critically discussed. And the current strategies in designing miRNA targeting therapeutics are described in detail. Finally, the current challenges and future perspectives of miRNA-based therapy are conferred.

LncRNA HOXA-AS2 Promotes Tumor Progression by Suppressing miR-567 Expression in Oral Squamous Cell Carcinoma

Introduction

Growing evidence suggests that long non-coding RNAs (lncRNAs), such as lncRNA HOXA-AS2, are critical regulators involved in human cancer. However, the biological functions and detailed mechanisms underlying how lncRNA HOXA-AS2 affects oral squamous cell carcinoma (OSCC) remain unexplored.

Methods

The expression of lncRNA HOXA-AS2 and miR-567 was determined in OSCC cell lines and clinical tissues by quantitative real-time PCR (qRT-PCR). Target site prediction and luciferase report assays were used to explore their potential interaction and binding sites between lncRNA HOXA-AS2 and miR-567. Overexpression or silencing expression of lncRNA HOXA-AS2 was performed to confirm that miR-567 was suppressed by lncRNA HOXA-AS2. WST-1 assay, crystal staining assay, and cell cycle analysis were used to assess the cell viability and proliferation ability. The target gene of miR-567 was predicted by Targetscan and validated by luciferase report assay as well as qRT-PCR and Western Blot. Xenograft nude mice model was done to demonstrate that lncRNA HOXA-AS2 promoted cell proliferation via targeting miR-567/CDK8 in vivo.

Results

LncRNA HOXA-AS2 was up-regulated in OSCC cells and tissues with the expression of miR-567 decreased. The tissue lncRNA HOXA-AS2 expression was found to positively correlate with the TNM stage and lymph node metastasis of OSCC patients. In terms of the mechanism, we found that lncRNA HOXA-AS2 negatively regulates miR-567 expression via a direct interaction. Functionally, overexpression of lncRNA HOXA-AS2 significantly promoted OSCC cell proliferation, while knockdown of lncRNA HOXA-AS2 significantly inhibited it. We also observed that miR-567 directly targets the 3' UTR of CDK8. Moreover, silencing lncRNA HOXA-AS2 inhibited tumor growth with the expression of miR-567 increased and CDK8 decreased in vivo.

Conclusion

LncRNA HOXA-AS2 was up-regulated in OSCC, and its up-regulation correlated with poor clinical outcomes. The lncRNA also promoted OSCC cell proliferation by directly binding to miR-567, leading to an increase in CDK8 expression. The potential prognostic value of lncRNA HOXA-AS2 should be explored in future studies.

Antiparasitic mebendazole (MBZ) effectively overcomes cisplatin resistance in human ovarian cancer cells by inhibiting multiple cancer-associated signaling pathways

Ovarian cancer is the third most common cancer and the second most common cause of gynecologic cancer death in women. Its routine clinical management includes surgical resection and systemic therapy with chemotherapeutics. While the first-line systemic therapy requires the combined use of platinum-based agents and paclitaxel, many ovarian cancer patients have recurrence and eventually succumb to chemoresistance. Thus, it is imperative to develop new strategies to overcome recurrence and chemoresistance of ovarian cancer. Repurposing previously-approved drugs is a cost-effective strategy for cancer drug discovery. The antiparasitic drug mebendazole (MBZ) is one of the most promising drugs with repurposing potential. Here, we investigate whether MBZ can overcome cisplatin resistance and sensitize chemoresistant ovarian cancer cells to cisplatin. We first established and characterized two stable and robust cisplatin-resistant (CR) human ovarian cancer lines and demonstrated that MBZ markedly inhibited cell proliferation, suppressed cell wounding healing/migration, and induced apoptosis in both parental and CR cells at low micromole range. Mechanistically, MBZ was revealed to inhibit multiple cancer-related signal pathways including ELK/SRF, NFKB, MYC/MAX, and E2F/DP1 in cisplatin-resistant ovarian cancer cells. We further showed that MBZ synergized with cisplatin to suppress cell proliferation, induce cell apoptosis, and blunt tumor growth in xenograft tumor model of human cisplatin-resistant ovarian cancer cells. Collectively, our findings suggest that MBZ may be repurposed as a synergistic sensitizer of cisplatin in treating chemoresistant human ovarian cancer, which warrants further clinical studies.

A functional autophagy pathway is essential for BMP9-induced osteogenic differentiation of mesenchymal stem cells (MSCs)

Mesenchymal stem cells (MSCs) are capable of differentiating into bone, cartilage and adipose tissues. We identified BMP9 as the most potent osteoinductive BMP although detailed mechanism underlying BMP9-regulated osteogenesis of MSCs is indeterminate. Emerging evidence indicates that autophagy plays a critical role in regulating bone homeostasis. We investigated the possible role of autophagy in osteogenic differentiation induced by BMP9. We showed that BMP9 upregulated the expression of multiple autophagy-related genes in MSCs. Autophagy inhibitor chloroquine (CQ) inhibited the osteogenic activity induced by BMP9 in MSCs. While overexpression of ATG5 or ATG7 did not enhance osteogenic activity induced by BMP9, silencing Atg5 expression in MSCs effectively diminished BMP9 osteogenic signaling activity and blocked the expression of the osteogenic regulator Runx2 and the late marker osteopontin induced by BMP9. Stem cell implantation study revealed that silencing Atg5 in MSCs profoundly inhibited ectopic bone regeneration and bone matrix mineralization induced by BMP9. Collectively, our results strongly suggest a functional autophagy pathway may play an essential role in regulating osteogenic differentiation induced by BMP9 in MSCs. Thus, restoration of dysregulated autophagic activity in MSCs may be exploited to treat fracture healing, bone defects or osteoporosis.

Circular RNAs: Expression, localization, and therapeutic potentials

Circular RNAs (circRNAs) are RNAs with a unique circular structure that is generated from back-splicing processes. These circular molecules were discovered more than 40 years ago but failed to raise scientific interest until lately. Increasing studies have found that these circular RNAs might not just be byproducts of the splicing process but possess important regulatory functions through different cellular events. Most circular RNAs are currently being studied in the field of cancer, and many of them have been confirmed to be involved in the process of tumorigenesis. However, many circular RNAs are implicated in the developmental stages of diseases other than cancer. In this review, we focus on discussing the role of circular RNAs in non-cancer diseases, especially in cardiovascular diseases. Following the summary of the life cycle of circRNAs, we provide input on studying circRNA-protein interactions based on our experience, which modulate protein translocation. Furthermore, we outline the potential of circRNAs to be potent biomarkers, effective therapeutic targets, and potential treatments in cardiovascular diseases as well as other non-cancer fields.

The Role of Noncoding RNAs in Osteogenic Differentiation of Human Periodontal Ligament Stem Cells

Chronic inflammatory diseases, including periodontitis, are the most common causes of bone tissue destruction. Periodontitis often leads to loss of connective tissue homeostasis and reduced alveolar bone levels. Human periodontal ligament stem cells (PDLSCs), a population of multipotent stem cells derived from periodontal ligament tissues, are considered as candidate cells for the regeneration of alveolar bone and periodontal tissues. Periodontitis impairs the osteogenic differentiation of human PDLSCs. Noncoding RNAs (ncRNAs), including long noncoding RNA (lncRNA), microRNA (miRNA), and circular RNA (circRNA), have been proposed as vital regulators influencing several differentiation processes including bone regeneration. Still, the molecular mechanisms of ncRNAs regulating osteogenic differentiation of human PDLSCs remain poorly understood. Exploring the influence of ncRNAs in the process of osteogenic differentiation of human PDLSCs may provide novel therapeutic strategies for tissue regeneration as the regeneration of the lost periodontium is the ultimate goal of periodontal therapy.

Integrative identification of the pathogenic role of a novel G6PD missense mutation c.697G>C

Background

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a hereditary disease caused by pathogenic mutations of G6PD. While most of the pathogenic variants of G6PD have been annotated, hemolysis of unknown etiology but analogous to that in G6PD deficiency persists, implying the existence of undocumented pathogenic variants. In our previous study, we reported four novel G6PD variants in China, for which the pathogenicity remains to be verified.

Methods

The variants were verified by exogenous expression in HEK-293 cells, and their functions were predicted by PolyPhen-2 and SIFT. The CRISPR/Cas9 system was exploited to edit the G6PD c.697G>C variant in HEK-293 cells and K562 cells. The expression of G6PD was detected by quantitative PCR (qPCR) and western blotting. The cell growth capacity was detected by the CCK-8 assay and crystal violet staining. The G6PD enzyme activity was reflected by the G6P/6PG ratio test. The apoptosis of cells was detected by Annexin V-APC/7-AAD staining. The secondary and crystallographic structures were denoted according to the literature and PyMOL software. The G6PD protein was purified from lysis of transformed Escherichia coli (E. coli) cell with Ni-charged Resin Column. The enzymatic activity was detected at different temperatures.

Results

The G6PD activity of exogenous G6PD c.697G>C in HEK-293 cells was significantly lower than that of wild type (WT) G6PD, a finding that was consistent with the observation in clinical samples. The functional predictions conducted by different algorithms indicated the damage role of the G6PD c.697G>C variant in its enzymatic activity. We recapitulated the G6PD c.697G>C variant both in HEK-293 cells and K562 cells by adapting the CRISPR/Cas9 strategy. Using distinct cell lines expressing the G6PD c.697G>C variant endogenously, we confirmed the deteriorative role of the G6PD c.697G>C variant in its enzymatic activity. Regarding the secondary and crystallographic structure, we found a mutated amino acid approaching the structural NADP⁺ binding site. Finally, we demonstrated the c.697G>C variant compromised the thermal stability of G6PD protein.

Conclusions

Our data delineated the pathogenic role of G6PD c.697G>C variant for G6PD deficiency, implying the wide usage of CRISPR/Cas9 for genetic disease research.

BMP4 augments the survival of hepatocellular carcinoma (HCC) cells under hypoxia and hypoglycemia conditions by promoting the glycolysis pathway

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death worldwide although its pathogenic mechanism remains to be fully understood. Unlike normal cells, most cancer cells rely on aerobic glycolysis and are more adaptable to the microenvironment of hypoxia and hypoglycemia. Bone Morphogenetic Protein 4 (BMP4) plays important roles in regulating proliferation, differentiation, invasion and migration of HCC cells. We have recently shown that BMP4 plays an important role in regulating glucose metabolism although the effect of BMP4 on glucose metabolic reprogramming of HCC is poorly understood. In this study, we found that BMP4 was highly expressed in HCC tumor tissues, as well as HCC cell lines that were tolerant to hypoxia and hypoglycemia. Mechanistically, we demonstrated that BMP4 protected HCC cells from hypoxia and hypoglycemia by promoting glycolysis since BMP4 up-regulated glucose uptake, the lactic acid production, the ATP level, and the activities of rate limiting enzymes of glycolysis (including HK2, PFK and PK). Furthermore, we demonstrated that BMP4 up-regulated HK2, PFKFB3 and PKM2 through the canonical Smad signal pathway as SMAD5 directly bound to the promoter of PKM. Collectively, our findings shown that BMP4 may play an important role in regulating glycolysis of HCC cells under hypoxia and hypoglycemia condition, indicating that novel therapeutics may be developed to target BMP4-regulated glucose metabolic reprogramming in HCC.

FAMSi: A Synthetic Biology Approach to the Fast Assembly of Multiplex siRNAs for Silencing Gene Expression in Mammalian Cells

RNA interference (RNAi) is mediated by an ∼21-nt double-stranded small interfering RNA (siRNA) and shows great promise in delineating gene functions and in developing therapeutics for human diseases. However, effective gene silencing usually requires the delivery of multiple siRNAs for a given gene, which is often technically challenging and time-consuming. In this study, by exploiting the type IIS restriction endonuclease-based synthetic biology methodology, we developed the fast assembly of multiplex siRNAs (FAMSi) system. In our proof-of-concept experiments, we demonstrated that multiple fragments containing three, four, or five siRNA sites targeting common Smad4 and/or BMPR-specific Smad1, Smad5, and Smad8 required for BMP9 signaling could be assembled efficiently. The constructed multiplex siRNAs effectively knocked down the expression of Smad4 and/or Smad1, Smad5, and Smad8 in mesenchymal stem cells (MSCs), and they inhibited all aspects of BMP9-induced osteogenic differentiation in bone marrow MSCs (BMSCs), including decreased expression of osteogenic regulators/markers, reduced osteogenic marker alkaline phosphatase (ALP) activity, and diminished in vitro matrix mineralization and in vivo ectopic bone formation. Collectively, we demonstrate that the engineered FAMSi system provides a fast-track platform for assembling multiplexed siRNAs in a single vector, and thus it may be a valuable tool to study gene functions or to develop novel siRNA-based therapeutics.

Bone morphogenetic protein 4 (BMP4) promotes hepatic glycogen accumulation and reduces glucose level in hepatocytes through mTORC2 signaling pathway

Liver is an important organ for regulating glucose and lipid metabolism. Recent studies have shown that bone morphogenetic proteins (BMPs) may play important roles in regulating glucose and lipid metabolism. In our previous studies, we demonstrated that BMP4 significantly inhibits hepatic steatosis and lowers serum triglycerides, playing a protective role against the progression of non-alcoholic fatty liver disease (NAFLD). However, the direct impact of BMP4 on hepatic glucose metabolism is poorly understood. Here, we investigated the regulatory roles of BMP4 in hepatic glucose metabolism. Through a comprehensive analysis of the 14 types of BMPs, we found that BMP4 was one of the most potent BMPs in promoting hepatic glycogen accumulation, reducing the level of glucose in hepatocytes and effecting the expression of genes related to glucose metabolism. Mechanistically, we demonstrated that BMP4 reduced the hepatic glucose levels through the activation of mTORC2 signaling pathway in vitro and in vivo. Collectively, our findings strongly suggest that BMP4 may play an essential role in regulating hepatic glucose metabolism. This knowledge should aid us to understand the molecular pathogenesis of NAFLD, and may lead to the development of novel therapeutics by exploiting the inhibitory effects of BMPs on hepatic glucose and lipid metabolism.

Circular RNAs in cancer: limitations in functional studies and diagnostic potential

Circular RNAs (circRNAs) are a large class of noncoding RNAs, generated from a process called back-splicing, that possess critical regulatory functions in many cellular events. A large body of literature has reported various circRNA functions and their underlying mechanisms, including sponging miRNA, exerting transcriptional and translational regulation, interacting with proteins, and translating into peptides and proteins. CircRNA dysregulation has been implicated in many cancers, including lung, breast, liver, gastric, colorectal, and ovarian cancer. They are detectable in bodily fluids and relatively stable, making them potential cancer biomarker candidates. Furthermore, targeting circRNA expression levels is a potential therapeutic approach for treating cancers. In this review, we describe the functional mechanisms of circRNAs and discuss limitations of current mechanism studies. Following this, we outline the potential of circRNAs to be effective biomarkers in various cancers and present circRNA-based therapeutic approaches. Finally, we discuss challenges in using circRNAs as diagnostic and therapeutic tools and propose future research directions.

Blockade of IGF/IGF-1R signaling axis with soluble IGF-1R mutants suppresses the cell proliferation and tumor growth of human osteosarcoma

Primary bone tumor, also known as osteosarcoma (OS), is the most common primary malignancy of bone in children and young adults. Current treatment protocols yield a 5-year survival rate of near 70% although approximately 80% of patients have metastatic disease at the time of diagnosis. However, long-term survival rates have remained virtually unchanged for nearly four decades, largely due to our limited understanding of the disease process. One major signaling pathway that has been implicated in human OS tumorigenesis is the insulin-like growth factor (IGF)/insulin-like growth factor-1 receptor (IGF1R) signaling axis. IGF1R is a heterotetrameric α2β2 receptor, in which the α subunits comprise the ligand binding site, whereas the β subunits are transmembrane proteins containing intracellular tyrosine kinase domains. Although numerous strategies have been devised to target IGF/IGF1R axis, most of them have failed in clinical trials due to the lack of specificity and/or limited efficacy. Here, we investigated whether a more effective and specific blockade of IGF1R activity in human OS cells can be accomplished by employing dominant-negative IGF1R (dnIGF1R) mutants. We engineered the recombinant adenoviruses expressing two IGF1R mutants derived from the α (aa 1-524) and β (aa 741-936) subunits, and found that either dnIGF1Rα and/or dnIGF1Rβ effectively inhibited cell migration, colony formation, and cell cycle progression of human OS cells, which could be reversed by exogenous IGF1. Furthermore, dnIGF1Rα and/or dnIGF1Rβ inhibited OS xenograft tumor growth in vivo, with the greatest inhibition of tumor growth shown by dnIGF1Rα. Mechanistically, the dnIGF1R mutants down-regulated the expression of PI3K/AKT and RAS/RAF/MAPK, BCL2, Cyclin D1 and most EMT regulators, while up-regulating pro-apoptotic genes in human OS cells. Collectively, these findings strongly suggest that the dnIGF1R mutants, especially dnIGF1Rα, may be further developed as novel anticancer agents that target IGF signaling axis with high specificity and efficacy.

Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNAs that can post-transcriptionally regulate the genes involved in critical cellular processes. The aberrant expressions of oncogenic or tumor suppressor miRNAs have been associated with cancer progression and malignancies. This resulted in the dysregulation of signaling pathways involved in cell proliferation, apoptosis and survival, metastasis, cancer recurrence and chemoresistance. In this review, we will first (i) provide an overview of the miRNA biogenesis pathways, and in vitro and in vivo models for research, (ii) summarize the most recent findings on the roles of microRNAs (miRNAs) that could potentially be used for miRNA-based therapy in the treatment of breast cancer and (iii) discuss the various therapeutic applications.

A simplified system for the effective expression and delivery of functional mature microRNAs in mammalian cells

MicroRNAs (miRNAs) are ~22 nucleotide noncoding RNAs that are involved in virtually all aspects of cellular process as their deregulations are associated with many pathological conditions. Mature miRNAs (mMIRs) are generated through a series of tightly-regulated nuclear and cytoplasmic processing events of the transcribed primary, precursor and mMIRs. Effective manipulations of miRNA expression enable us to gain insights into miRNA functions and to explore potential therapeutic applications. Currently, overexpression of miRNAs is achieved by using chemically-synthesized miRNA mimics, or shRNA-like stem-loop vectors to express primary or precursor miRNAs, which are limited by low transfection efficacy or rate-limiting miRNA processing. To overcome rate-limiting miRNA processing, we developed a novel strategy to express mMIRs which are driven by converging U6/H1 dual promoters. As a proof-of-concept study, we constructed mMIR expression vectors for hsa-miR-223 and hsa-Let-7a-1, and demonstrated that the expressed mMIRs effectively silenced target gene expression, specifically suppressed miRNA reporter activity, and significantly affected cell proliferation, similar to respective primary and precursor miRNAs. Furthermore, these mMIR expression vectors can be easily converted into retroviral and adenoviral vectors. Collectively, our simplified mMIR expression system should be a valuable tool to study miRNA functions and/or to deliver miRNA-based therapeutics.

Therapeutic Potential of Circular RNAs in Osteosarcoma

Osteosarcoma is the most common malignant bone tumor in children and adolescents. Multiagent chemotherapy, together with surgical removal of all detectable lesions, has improved the long-term survival rate to 65-70% in patients with localized osteosarcoma and to 25-30% in patients with metastatic osteosarcoma since the 1970s. However, the conventional strategy has not improved in recent decades. With accumulating knowledge of the natural circular RNA (circRNA) pathogenesis of osteosarcoma, the diagnostic and therapeutic potential of some circRNAs has been explored. Meanwhile, artificial circular RNAs have been designed as onco-microRNA inhibitors to exert antitumor functions. Therefore, natural and artificial circular RNAs, like other RNA counterparts, are attractive new classes of therapeutic molecules for the treatment of osteosarcoma. This review summarizes the latest progress in the relationship between circRNAs and the malignant phenotype of osteosarcoma and sheds light on the therapeutic potential of the two types of circular RNA in the clinic.

Leptin Potentiates BMP9-Induced Osteogenic Differentiation of Mesenchymal Stem Cells Through the Activation of JAK/STAT Signaling

Mesenchymal stem cells (MSCs) are multipotent progenitors that have the ability to differentiate into multiple lineages, including bone, cartilage, and fat. We previously demonstrated that the least known bone morphogenetic protein (BMP)9 (also known as growth differentiation factor 2) is one of the potent osteogenic factors that can induce both osteogenic and adipogenic differentiation of MSCs. Nonetheless, the molecular mechanism underlying BMP9 action remains to be fully understood. Leptin is an adipocyte-derived hormone in direct proportion to the amount of body fat, and exerts pleiotropic functions, such as regulating energy metabolism, bone mass, and mineral density. In this study, we investigate the potential effect of leptin signaling on BMP9-induced osteogenic differentiation of MSCs. We found that exogenous leptin potentiated BMP9-induced osteogenic differentiation of MSCs both in vitro and in vivo, while inhibiting BMP9-induced adipogenic differentiation. BMP9 was shown to induce the expression of leptin and leptin receptor in MSCs, while exogenous leptin upregulated BMP9 expression in less differentiated MSCs. Mechanistically, we demonstrated that a blockade of JAK signaling effectively blunted leptin-potentiated osteogenic differentiation induced by BMP9. Taken together, our results strongly suggest that leptin may potentiate BMP9-induced osteogenesis by cross-regulating BMP9 signaling through the JAK/STAT signaling pathway in MSCs. Thus, it is conceivable that a combined use of BMP9 and leptin may be explored as a novel approach to enhancing efficacious bone regeneration and fracture healing.

Long non-coding RNA (lncRNA) H19 induces hepatic steatosis through activating MLXIPL and mTORC1 networks in hepatocytes

Liver plays an essential role in regulating lipid metabolism, and chronically disturbed hepatic metabolism may cause obesity and metabolic syndrome, which may lead to non-alcoholic fatty liver disease (NAFLD). Increasing evidence indicates long non-coding RNAs (lncRNAs) play an important role in energy metabolism. Here, we investigated the role of lncRNA H19 in hepatic lipid metabolism and its potential association with NAFLD. We found that H19 was up-regulated in oleic acid-induced steatosis and during the development of high-fat diet (HFD)-induced NAFLD. Exogenous overexpression of H19 in hepatocytes induced lipid accumulation and up-regulated the expression of numerous genes involved in lipid synthesis, storage and breakdown, while silencing endogenous H19 led to a decreased lipid accumulation in hepatocytes. Mechanistically, H19 was shown to promote hepatic steatosis by up-regulating lipogenic transcription factor MLXIPL. Silencing Mlxipl diminished H19-induced lipid accumulation in hepatocytes. Furthermore, H19-induced lipid accumulation was effectively inhibited by PI3K/mTOR inhibitor PF-04691502. Accordingly, H19 overexpression in hepatocytes up-regulated most components of the mTORC1 signalling axis, which were inhibited by silencing endogenous H19. In vivo hepatocyte implantation studies further confirm that H19 promoted hepatic steatosis by up-regulating both mTORC1 signalling axis and MLXIPL transcriptional network. Collectively, these findings strongly suggest that H19 may play an important role in regulating hepatic lipid metabolism and may serve as a potential therapeutic target for NAFLD.

Strong Inhibitory Effects of Antisense Probes on Gene Expression through Ultrafast RNA Photocrosslinking

We have reported the photochemical regulation of the intracellular antisense effect of antisense probes containing a photo-responsive artificial nucleic acid, 3-cyanovinylcarbazole nucleoside (^CNV K). Here we focus on the importance of the photocrosslinking rate on the inhibitory effect on gene expression using photocrosslinkable antisense probes (pcASOs). The inhibitory effect of pcASOs on GFP gene expression was dependent on the photocrosslinking rate of 3-cyanovinylcarbazole with d-threoninol (^CNV D), ^CNV K, or psoralen. The ultrafast RNA photocrosslinking induced the formation of a thermally irreversible covalent bond between pcASOs and the target RNA. These ASOs strongly inhibited gene expression only when the photocrosslinking rate was faster than the random walk of branch migration. In addition, pcASOs containing ^CNV D or ^CNV K targeted the RNAs with secondary structures. These results indicate the regulatory effect of photocrosslinker and photoirradiation energy using pcASOs on the gene expression level.