MiR-122/cyclin G1 interaction modulates p53 activity and affects doxorubicin sensitivity of human hepatocarcinoma cells

Genetic Alchemy unveiled: MicroRNA-mediated gene therapy as the Artisan craft in the battlefront against hepatocellular carcinoma-a comprehensive chronicle of strategies and innovations

Investigating therapeutic miRNAs is a rewarding endeavour for pharmaceutical companies. Since its discovery in 1993, our understanding of miRNA biology has advanced significantly. Numerous studies have emphasised the disruption of miRNA expression in various diseases, making them appealing candidates for innovative therapeutic approaches. Hepatocellular carcinoma (HCC) is a significant malignancy that poses a severe threat to human health, accounting for approximately 70%-85% of all malignant tumours. Currently, the efficacy of several HCC therapies is limited. Alterations in various biomacromolecules during HCC progression and their underlying mechanisms provide a basis for the investigation of novel and effective therapeutic approaches. MicroRNAs, also known as miRNAs, have been identified in the last 20 years and significantly impact gene expression and protein translation. This atypical expression pattern is strongly associated with the onset and progression of various malignancies. Gene therapy, a novel form of biological therapy, is a prominent research area. Therefore, miRNAs have been used in the investigation of tumour gene therapy. This review examines the mechanisms of action of miRNAs, explores the correlation between miRNAs and HCC, and investigates the use of miRNAs in HCC gene therapy.

How MicroRNAs Command the Battle against Cancer

MicroRNAs (miRNAs) are small RNA molecules that regulate more than 30% of genes in humans. Recent studies have revealed that miRNAs play a crucial role in tumorigenesis. Large sets of miRNAs in human tumors are under-expressed compared to normal tissues. Furthermore, experiments have shown that interference with miRNA processing enhances tumorigenesis. Multiple studies have documented the causal role of miRNAs in cancer, and miRNA-based anticancer therapies are currently being developed. This review primarily focuses on two key points: (1) miRNAs and their role in human cancer and (2) the regulation of tumor suppressors by miRNAs. The review discusses (a) the regulation of the tumor suppressor p53 by miRNA, (b) the critical role of the miR-144/451 cluster in regulating the Itch-p63-Ago2 pathway, and (c) the regulation of PTEN by miRNAs. Future research and the perspectives of miRNA in cancer are also discussed. Understanding these pathways will open avenues for therapeutic interventions targeting miRNA regulation.

Engineering Versatile Nanomedicines for Ultrasonic Tumor Immunotherapy

Due to the specific advantages of ultrasound (US) in therapeutic disease treatments, the unique therapeutic US technology has emerged. In addition to featuring a low-invasive targeted cancer-cell killing effect, the therapeutic US technology has been demonstrated to modulate the tumor immune landscape, amplify the therapeutic effect of other antitumor therapies, and induce immunosensitization of tumors to immunotherapy, shedding new light on the cancer treatment. Tremendous advances in nanotechnology are also expected to bring unprecedented benefits to enhancing the antitumor efficiency and immunological effects of therapeutic US, as well as therapeutic US-derived bimodal and multimodal synergistic therapies. This comprehensive review summarizes the immunological effects induced by different therapeutic US technologies, including ultrasound-mediated micro-/nanobubble destruction (UTMD/UTND), sonodynamic therapy (SDT), and focused ultrasound (FUS), as well as the main underlying mechanisms involved. It is also discussed that the recent research progress of engineering intelligent nanoplatform in improving the antitumor efficiency of therapeutic US technologies. Finally, focusing on clinical translation, the key issues and challenges currently faced are summarized, and the prospects for promoting the clinical translation of these emerging nanomaterials and ultrasonic immunotherapy in the future are proposed.

The Impact of miR-122 on Cancer

MiRNAs are confirmed to be a kind of short and eminently conserved noncoding RNAs, which regulate gene expression at the post-transcriptional level via binding to the 3'- untranslated region (3'-UTR) of targeting multiple target messenger RNAs. Recently, growing evidence stresses the point that they play a crucial role in a variety of pathological processes, including human cancers. Dysregulated miRNAs act as oncogenes or tumor suppressor genes in many cancer types. Among them, we noticed that miR-122 has been widely reported to significantly influence carcinogenicity in a variety of tumors by regulating target genes and signaling pathways. Here, we focused on the expression of miR-122 in regulatory mechanisms and tumor biological processes. We also discussed the effects of miR-122 dysregulation in various types of human malignancies and the potential to develop new molecular miR-122-targeted therapies. The present review suggests that miR-122 may be a potentially useful cancer diagnosis and treatment biomarker. More clinical diagnoses need to be further launched in the future. A promising direction to improve the outcomes for cancer patients will likely combine miR-122 with other traditional tumor biomarkers.

Role of Non-Coding RNAs in Hepatocellular Carcinoma Progression: From Classic to Novel Clinicopathogenetic Implications

Hepatocellular carcinoma (HCC) is a predominant malignancy with increasing incidences and mortalities worldwide. In Western countries, the progressive affirmation of Non-alcoholic Fatty Liver Disease (NAFLD) as the main chronic liver disorder in which HCC occurrence is appreciable even in non-cirrhotic stages, constitutes a real health emergency. In light of this, a further comprehension of molecular pathways supporting HCC onset and progression represents a current research challenge to achieve more tailored prognostic models and appropriate therapeutic approaches. RNA non-coding transcripts (ncRNAs) are involved in the regulation of several cancer-related processes, including HCC. When dysregulated, these molecules, conventionally classified as "small ncRNAs" (sncRNAs) and "long ncRNAs" (lncRNAs) have been reported to markedly influence HCC-related progression mechanisms. In this review, we describe the main dysregulated ncRNAs and the relative molecular pathways involved in HCC progression, analyzing their implications in certain etiologically related contexts, and their applicability in clinical practice as novel diagnostic, prognostic, and therapeutic tools. Finally, given the growing evidence supporting the immune system response, the oxidative stress-regulated mechanisms, and the gut microbiota composition as relevant emerging elements mutually influencing liver-cancerogenesis processes, we investigate the relationship of ncRNAs with this triad, shedding light on novel pathogenetic frontiers of HCC progression.

The role and mechanism of action of microRNA-122 in cancer: Focusing on the liver

microRNA-122 (miR-122) is a highly conserved microRNA that is predominantly expressed in the liver and plays a critical role in the regulation of liver metabolism. Recent studies have shown that miR-122 is involved in the pathogenesis of various types of cancer, particularly liver cancer. In this sense, The current findings highlighted the potential role of miR-122 in regulating many vital processes in cancer pathophysiology, including apoptosis, signaling pathway, cell metabolism, immune system response, migration, and invasion. These results imply that miR-122, which has been extensively studied for its biological functions and potential therapeutic applications, acts as a tumor suppressor or oncogene in cancer development. We first provide an overview and summary of the physiological function and mode of action of miR-122 in liver cancer. We will examine the various signaling pathways and molecular mechanisms through which miR-122 exerts its effects on cancer cells, including the regulation of oncogenic and tumor suppressor genes, the modulation of cell proliferation and apoptosis, and the regulation of metastasis. Most importantly, we will also discuss the potential diagnostic and therapeutic applications of miR-122 in cancer, including the development of miRNA-based biomarkers for cancer diagnosis and prognosis, and the potential use of miR-122 as a therapeutic target for cancer treatment.

Doxorubicin and other anthracyclines in cancers: Activity, chemoresistance and its overcoming

Anthracyclines have been important and effective treatments against a number of cancers since their discovery. However, their use in therapy has been complicated by severe side effects and toxicity that occur during or after treatment, including cardiotoxicity. The mode of action of anthracyclines is complex, with several mechanisms proposed. It is possible that their high toxicity is due to the large set of processes involved in anthracycline action. The development of resistance is a major barrier to successful treatment when using anthracyclines. This resistance is based on a series of mechanisms that have been studied and addressed in recent years. This work provides an overview of the anthracyclines used in cancer therapy. It discusses their mechanisms of activity, toxicity, and chemoresistance, as well as the approaches used to improve their activity, decrease their toxicity, and overcome resistance.

miR‑122/SENP1 axis confers stemness and chemoresistance to liver cancer through Wnt/β‑catenin signaling

The property of inherent stemness of tumor cells coupled with the development of chemoresistance results in a poor prognosis for patients with liver cancer. Therefore, the present study focused on microRNA (miR)-122, a potential tumor suppressor, the expression of which has been previously shown to be significantly decreased and negatively associated with cancer cell stemness in liver cancer. The present study aimed to identify the molecular targets of miR-122 whilst uncovering the mechanism underlying chemoresistance and stemness of HepG2 cells in liver cancer. Bioinformatics online tools, such as ENCORI, coupled with dual-luciferase reporter assays in HepG2 cells, were used to identify and validate small ubiquitin-like modifier (SUMO) specific peptidase 1 (SENP1) as a potential target of miR-122 in liver cancer. The liver cancer stem cell population was determined using sphere formation assays and flow cytometry, whilst stem cell markers (Oct3/4, Nanog, B lymphoma Mo-MLV insertion region 1 homolog and Notch1) were detected by reverse transcription-quantitative PCR. Chemoresistance, cell proliferation and migratory ability of HepG2 cells were monitored using Cell Counting Kit-8, colony formation and Transwell assays, respectively. The overexpression of miR-122 by mimic transfection led to a significant decrease in the number spheres, downregulation of stem cell marker expression, the number of CD24+ cells, drug-resistance protein levels (P-glycoprotein and multidrug resistance protein), impaired chemoresistance, proliferation and migration of HepG2 cells. The transfection of SENP1 overexpression vector resulted in contrasting functions to miR-122 mimics, by partially reversing the effects induced by miR-122 mimic transfection in HepG2 cells. Wnt/β-catenin signaling has been proven to be involved in cancer stemness and malignant behavior. Western blotting analysis in HepG2 cells showed that the expression levels of both Wnt1 and β-catenin were significantly reduced after overexpressing miR-122, but increased after overexpressing SENP1. Co-transfection with the SENP1 overexpression vector reversed the suppression induced by the miR-122 mimics on Wnt1 and β-catenin expression. Co-immunoprecipitation, SUMOylation and half-life assays showed SENP1 interacted with β-catenin and decreased the SUMOylation of β-catenin, thereby enhancing its stability. Finally, tumor xenograft analyses revealed that HepG2 cells transfected with Agomir-122 exerted significantly lower tumor initiation frequency and growth rate, and a superior response to DOX in vivo, compared with those transfected with Agomir NC. Taken together, data from the present study miR-122/SENP1 axis can regulate β-catenin stability through de-SUMOylation, thereby promoting stemness and chemoresistance in liver cancer.

Widespread 8-oxoguanine modifications of miRNA seeds differentially regulate redox-dependent cancer development

Oxidative stress contributes to tumourigenesis by altering gene expression. One accompanying modification, 8-oxoguanine (o8G) can change RNA-RNA interactions via o8G•A base pairing, but its regulatory roles remain elusive. Here, on the basis of o8G-induced guanine-to-thymine (o8G > T) variations featured in sequencing, we discovered widespread position-specific o8Gs in tumour microRNAs, preferentially oxidized towards 5' end seed regions (positions 2-8) with clustered sequence patterns and clinically associated with patients in lower-grade gliomas and liver hepatocellular carcinoma. We validated that o8G at position 4 of miR-124 (4o8G-miR-124) and 4o8G-let-7 suppress lower-grade gliomas, whereas 3o8G-miR-122 and 4o8G-let-7 promote malignancy of liver hepatocellular carcinoma by redirecting the target transcriptome to oncogenic regulatory pathways. Stepwise oxidation from tumour-promoting 3o8G-miR-122 to tumour-suppressing 2,3o8G-miR-122 occurs and its specific modulation in mouse liver effectively attenuates diethylnitrosamine-induced hepatocarcinogenesis. These findings provide resources and insights into epitranscriptional o8G regulation of microRNA functions, reprogrammed by redox changes, implicating its control for cancer treatment.

Recent progress in the immunotherapy of hepatocellular carcinoma: Non-coding RNA-based immunotherapy may improve the outcome

Hepatocellular carcinoma (HCC) is the second most lethal cancer and a leading cause of cancer-related mortality worldwide. Immune checkpoint inhibitors (ICIs) significantly improved the prognosis of HCC; however, the therapeutic response remains unsatisfactory in a substantial proportion of patients or needs to be further improved in responders. Herein, other methods of immunotherapy, including vaccine-based immunotherapy, adoptive cell therapy, cytokine delivery, kynurenine pathway inhibition, and gene delivery, have been adopted in clinical trials. Although the results were not encouraging enough to expedite their marketing. A major proportion of human genome is transcribed into non-coding RNAs (ncRNAs). Preclinical studies have extensively investigated the roles of ncRNAs in different aspects of HCC biology. HCC cells reprogram the expression pattern of numerous ncRNAs to decrease the immunogenicity of HCC, exhaust the cytotoxic and anti-cancer function of CD8 + T cells, natural killer (NK) cells, dendritic cells (DCs), and M1 macrophages, and promote the immunosuppressive function of T Reg cells, M2 macrophages, and myeloid-derived suppressor cells (MDSCs). Mechanistically, cancer cells recruit ncRNAs to interact with immune cells, thereby regulating the expression of immune checkpoints, functional receptors of immune cells, cytotoxic enzymes, and inflammatory and anti-inflammatory cytokines. Interestingly, prediction models based on the tissue expression or even serum levels of ncRNAs could predict response to immunotherapy in HCC. Moreover, ncRNAs markedly potentiated the efficacy of ICIs in murine models of HCC. This review article first discusses recent advances in the immunotherapy of HCC, then dissects the involvement and potential application of ncRNAs in the immunotherapy of HCC.

The role of mesenchymal stem cells derived exosomes as a novel nanobiotechnology target in the diagnosis and treatment of cancer

Mesenchymal stem cells (MSCs), one of the most common types of stem cells, are involved in the modulation of the tumor microenvironment (TME). With the advancement of nanotechnology, exosomes, especially exosomes secreted by MSCs, have been found to play an important role in the initiation and development of tumors. In recent years, nanobiotechnology and bioengineering technology have been gradually developed to detect and identify exosomes for diagnosis and modify exosomes for tumor treatment. Several novel therapeutic strategies bioengineer exosomes to carry drugs, proteins, and RNAs, and further deliver their encapsulated cargoes to cancer cells through the properties of exosomes. The unique properties of exosomes in cancer treatment include targeting, low immunogenicity, flexibility in modification, and high biological barrier permeability. Nevertheless, the current comprehensive understanding of the roles of MSCs and their secreted exosomes in cancer development remain inadequate. It is necessary to better understand/update the mechanism of action of MSCs-secreted exosomes in cancer development, providing insights for better modification of exosomes through bioengineering technology and nanobiotechnology. Therefore, this review focuses on the role of MSCs-secreted exosomes and bioengineered exosomes in the development, progression, diagnosis, and treatment of cancer.

Double-edged sword role of miRNA-633 and miRNA-181 in human cancers

Understanding the function and mode of operation of microRNAs (miRNAs) in cancer is of growing interest. The short non-coding RNAs known as miRNAs, which target mRNA in multicellular organisms, are described as controlling essential cellular processes. The miR-181 family and miR-633 are well-known miRNAs that play a key role in the development and metastasis of tumor cells. They may facilitate either tumor-suppressive or oncogenic function in malignant cells, according to mounting evidence. Metastatic cells that are closely linked to cancer cell migration, invasion, and angiogenesis can be identified by abnormal levels of miR-181 and miR-633. Numerous studies have demonstrated their capacity to control drug resistance, cell growth, apoptosis, and the epithelial-mesenchymal transition (EMT) and metastasis process. Interestingly, the levels of miR-181 and miR-633 and their potential target genes in the basic cellular process can vary depending on the type of cancer cells and their gene expression profile. Such miRNAs' interactions with other non-coding RNAs such as long non-coding RNAs and circular RNAs can influence tumor behaviors. Herein, we concentrated on the multifaceted roles of miR-181 and miR-633 and potential targets in human tumorigenesis, ranging from cell growth and metastasis to drug resistance.

Tumor Microenvironment Remodeling in Gastrointestinal Cancer: Role of miRNAs as Biomarkers of Tumor Invasion

Gastrointestinal (GI) cancers are the most frequent neoplasm, responsible for half of all cancer-related deaths. Metastasis is the leading cause of death from GI cancer; thus, studying the processes that regulate cancer cell migration is of paramount importance for the development of new therapeutic strategies. In this review, we summarize the mechanisms adopted by cancer cells to promote cell migration and the subsequent metastasis formation by highlighting the key role that tumor microenvironment components play in deregulating cellular pathways involved in these processes. We, therefore, provide an overview of the role of different microRNAs in promoting tumor metastasis and their role as potential biomarkers for the prognosis, monitoring, and diagnosis of GI cancer patients. Finally, we relate the possible use of nutraceuticals as a new strategy for targeting numerous microRNAs and different pathways involved in GI tumor invasiveness.

An Insight into the Arising Role of MicroRNAs in Hepatocellular Carcinoma: Future Diagnostic and Therapeutic Approaches

Hepatocellular carcinoma (HCC) constitutes a frequent highly malignant form of primary liver cancer and is the third cause of death attributable to malignancy. Despite the improvement in the therapeutic strategies with the exploration of novel pharmacological agents, the survival rate for HCC is still low. Shedding light on the multiplex genetic and epigenetic background of HCC, such as on the emerging role of microRNAs, is considered quite promising for the diagnosis and the prediction of this malignancy, as well as for combatting drug resistance. MicroRNAs (miRNAs) constitute small noncoding RNA sequences, which play a key role in the regulation of several signaling and metabolic pathways, as well as of pivotal cellular functions such as autophagy, apoptosis, and cell proliferation. It is also demonstrated that miRNAs are significantly implicated in carcinogenesis, either acting as tumor suppressors or oncomiRs, while aberrations in their expression levels are closely associated with tumor growth and progression, as well as with local invasion and metastatic dissemination. The arising role of miRNAs in HCC is in the spotlight of the current scientific research, aiming at the development of novel therapeutic perspectives. In this review, we will shed light on the emerging role of miRNAs in HCC.

Exosomal miRNA in early-stage hepatocellular carcinoma

The incidence and mortality of hepatic carcinoma (HCC) remain high, and early diagnosis of HCC is seen as a key approach in improving clinical outcomes. However, the sensitivity and specificity of current early screening methods for HCC are not satisfactory. In recent years, research around exosomal miRNA has gradually increased, and these molecules have emerged as attractive candidates for early diagnosis and treatment of HCC. This review summarizes the feasibility of using miRNAs in peripheral blood exosomes as early diagnostic tools for HCC.

Long Non-Coding RNAs as Novel Targets for Phytochemicals to Cease Cancer Metastasis

Metastasis is a multi-step phenomenon during cancer development leading to the propagation of cancer cells to distant organ(s). According to estimations, metastasis results in over 90% of cancer-associated death around the globe. Long non-coding RNAs (LncRNAs) are a group of regulatory RNA molecules more than 200 base pairs in length. The main regulatory activity of these molecules is the modulation of gene expression. They have been reported to affect different stages of cancer development including proliferation, apoptosis, migration, invasion, and metastasis. An increasing number of medical data reports indicate the probable function of LncRNAs in the metastatic spread of different cancers. Phytochemical compounds, as the bioactive agents of plants, show several health benefits with a variety of biological activities. Several phytochemicals have been demonstrated to target LncRNAs to defeat cancer. This review article briefly describes the metastasis steps, summarizes data on some well-established LncRNAs with a role in metastasis, and identifies the phytochemicals with an ability to suppress cancer metastasis by targeting LncRNAs.

Expression analysis of circulating miR-22, miR-122, miR-217 and miR-367 as promising biomarkers of acute lymphoblastic leukemia

BACKGROUND

The role of serum-based biomarkers such as microRNAs in cancer diagnosis has been extensively established. This study aimed to determine the expression levels of bioinformatically selected miRNAs and whether they can be used as biomarkers or a new therapeutic target in patients with acute lymphoblastic leukemia (ALL).

MATERIALS AND METHODS

The expression levels of serum miR-22, miR-122, miR-217, and miR-367 in 21 ALL patients and 21 healthy controls were measured using quantitative real-time PCR. The receiver operating characteristic (ROC) curve and the associated area under the curve (AUC) was used to assess candidate miRNAs' diagnostic value as a biomarker.

RESULTS

The results showed that miR-217 was markedly decreased in patients with ALL compared to controls. Moreover, miR-22, miR-122, and miR-367 were found to be upregulated. Furthermore, ROC analysis showed that serum miR-217 and miR-367 could differentiate ALL patients from healthy individuals, while miR-22 has approximate discriminatory power that requires further investigation.

CONCLUSION

These results provide promising preliminary evidence that circulating miR-217 and miR-367 could be considered potent diagnostic biomarkers and therapeutic goals in this disease.

Non-Coding RNAs in Hepatocellular Carcinoma

Liver cancer ranks as the fourth leading cause of cancer-related deaths. Despite extensive research efforts aiming to evaluate the biological mechanisms underlying hepatocellular carcinoma (HCC) development, little has been translated towards new diagnostic and treatment options for HCC patients. Historically, the focus has been centered on coding RNAs and their respective proteins. However, significant advances in sequencing and RNA detection technologies have shifted the research focus towards non-coding RNAs (ncRNA), as well as their impact on HCC development and progression. A number of studies reported complex post-transcriptional interactions between various ncRNA and coding RNA molecules. These interactions offer insights into the role of ncRNAs in both the known pathways leading to oncogenesis, such as dysregulation of p53, and lesser-known mechanisms, such as small nucleolar RNA methylation. Studies investigating these mechanisms have identified prevalent ncRNA changes in microRNAs, snoRNAs, and long non-coding RNAs that can both pre- and post-translationally regulate key factors in HCC progression. In this review, we present relevant publications describing ncRNAs to summarize the impact of different ncRNA species on liver cancer development and progression and to evaluate recent attempts at clinical translation.

Molecular Targets and Signaling Pathways of microRNA-122 in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading global causes of cancer mortality. MicroRNAs (miRNAs) are small interfering RNAs that alleviate the levels of protein expression by suppressing translation, inducing mRNA cleavage, and promoting mRNA degradation. miR-122 is the most abundant miRNA in the liver and is responsible for several liver-specific functions, including metabolism, cellular growth and differentiation, and hepatitis virus replication. Recent studies have shown that aberrant regulation of miR-122 is a key factor contributing to the development of HCC. In this review, the signaling pathways and the molecular targets of miR-122 involved in the progression of HCC have been summarized, and the importance of miR-122 in therapy has been discussed.

Tumor-associated Exosomes Are Involved in Hepatocellular Carcinoma Tumorigenesis, Diagnosis, and Treatment

Hepatocellular carcinoma (HCC) has become a challenging disease worldwide. There are still limitations in the diagnosis and treatment of HCC, and its high metastatic capacity and high recurrence rate are the main reasons for its poor prognosis. The ability of extracellular vesicles (EVs) to transfer functionally-active substances and their widespread presence in almost all body fluids suggest their unprecedented potential in the study of various cancers. The unique physicochemical properties of EVs determine their potential as antitumor vaccines and drug carriers. In the last decade, the study of EVs in HCC has evolved from a single hot topic to a system with considerable scale. This paper summarizes the role of EVs, especially exosomes, in the occurrence, metastasis and tumor immunity of HCC, reviews their applications in tumor diagnosis, prognosis and treatment, describes the pros and cons of these studies, and looks forward towards the future research directions of EVs in HCC.

Hepatocellular Carcinoma: The Role of MicroRNAs

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. HCC is diagnosed in its advanced stage when limited treatment options are available. Substantial morphologic, genetic and epigenetic heterogeneity has been reported in HCC, which poses a challenge for the development of a targeted therapy. In this review, we discuss the role and involvement of several microRNAs (miRs) in the heterogeneity and metastasis of hepatocellular carcinoma with a special emphasis on their possible role as a diagnostic and prognostic tool in the risk prediction, early detection, and treatment of hepatocellular carcinoma.

The Roles of microRNAs in Cancer Multidrug Resistance

Simple Summary

The resistance of neoplastic cells to multiple drugs is a serious problem in cancer chemotherapy. The molecular causes of multidrug resistance in cancer are largely known, but less is known about the mechanisms by which cells deliver phenotypic changes that resist the attack of anticancer drugs. The findings of RNA interference based on microRNAs represented a breakthrough in biology and pointed to the possibility of sensitive and targeted regulation of gene expression at the post-transcriptional level. Such regulation is also involved in the development of multidrug resistance in cancer. The aim of the current paper is to summarize the available knowledge on the role of microRNAs in resistance to multiple cancer drugs.

Abstract

Cancer chemotherapy may induce a multidrug resistance (MDR) phenotype. The development of MDR is based on various molecular causes, of which the following are very common: induction of ABC transporter expression; induction/activation of drug-metabolizing enzymes; alteration of the expression/function of apoptosis-related proteins; changes in cell cycle checkpoints; elevated DNA repair mechanisms. Although these mechanisms of MDR are well described, information on their molecular interaction in overall multidrug resistance is still lacking. MicroRNA (miRNA) expression and subsequent RNA interference are candidates that could be important players in the interplay of MDR mechanisms. The regulation of post-transcriptional processes in the proteosynthetic pathway is considered to be a major function of miRNAs. Due to their complementarity, they are able to bind to target mRNAs, which prevents the mRNAs from interacting effectively with the ribosome, and subsequent degradation of the mRNAs can occur. The aim of this paper is to provide an overview of the possible role of miRNAs in the molecular mechanisms that lead to MDR. The possibility of considering miRNAs as either specific effectors or interesting targets for cancer therapy is also analyzed.

Progress of HOTAIR-microRNA in hepatocellular carcinoma

The Hox transcript antisense intergenic RNA (HOTAIR) has been identified as a tumor gene, and its expression in HCC is significantly increased. HOTAIR is associated with the proliferation, invasion, metastasis and poor prognosis of HCC. In addition, HOTAIR can also regulate the expression and function of microRNA by recruiting the polycomb repressive complex 2 (PRC2) and competitive adsorption, thus promoting the occurrence and development of HCC. In this review, we discussed the two mechanisms of HOTAIR regulating miRNA through direct binding miRNA and indirect regulation, and emphasized the role of HOTAIR in HCC through miRNA, explained the regulatory pathway of HOTAIR-miRNA-mRNA and introduced the role of this pathway in HCC proliferation, drug resistance, invasion and metastasis.

Spectrum of microRNAs and their target genes in cancer: intervention in diagnosis and therapy

Till date, several groups have studied the mechanism of microRNA (miRNA) biogenesis, processing, stability, silencing, and their dysregulation in cancer. The miRNA coding genes recurrently go through abnormal amplification, deletion, transcription, and epigenetic regulation in cancer. Some miRNAs function as tumor promoters while few others are tumor suppressors based on the transcriptional regulation of target genes. A review of miRNAs and their target genes in a wide range of cancers is attempted in this article, which may help in the development of new diagnostic tools and intervention therapies. The contribution of miRNAs for drug sensitivity or resistance in cancer therapy and opportunities of miRNAs in cancer prognosis or diagnosis and therapy is also presented in detail.

Mesenchymal stem cell-derived exosomes for gastrointestinal cancer

Gastrointestinal (GI) malignancies, a series of malignant conditions originating from the digestive system, include gastric cancer, hepatocellular carcinoma, pancreatic cancer, and colorectal cancer. GI cancers have been regarded as the leading cancer-related cause of death in recent years. Therefore, it is essential to develop effective treatment strategies for GI malignancies. Mesenchymal stem cells (MSCs), a type of distinct non-hematopoietic stem cells and an important component of the tumor microenvironment, play important roles in regulating GI cancer development and progression through multiple mechanisms, such as secreting cytokines and direct interactions. Currently, studies are focusing on the anti-cancer effect of MSCs on GI malignancies. However, the effects and functional mechanisms of MSC-derived exosomes on GI cancer are less studied. MSC-derived exosomes can regulate GI tumor growth, drug response, metastasis, and invasion through transplanting proteins and miRNA to tumor cells to activate the specific signal pathway. Besides, the MSC-derived exosomes are also seen as an important drug delivery system and have shown potential in anti-cancer treatment. This study aims to summarize the effect and biological functions of MSC-derived exosomes on the development of GI cancers and discuss their possible clinical applications for the treatment of GI malignancies.

An AAV gene therapy computes over multiple cellular inputs to enable precise targeting of multifocal hepatocellular carcinoma in mice

[Figure: see text].

The role of non-coding RNAs in chemotherapy for gastrointestinal cancers

Gastrointestinal (GI) cancers, including colorectal, gastric, hepatic, esophageal, and pancreatic tumors, are responsible for large numbers of deaths around the world. Chemotherapy is the most common approach used to treat advanced GI cancer. However, chemoresistance has emerged as a critical challenge that prevents successful tumor elimination, leading to metastasis and recurrence. Chemoresistance mechanisms are complex, and many factors and pathways are involved. Among these factors, non-coding RNAs (ncRNAs) are critical regulators of GI tumor development and subsequently can induce resistance to chemotherapy. This occurs because ncRNAs can target multiple signaling pathways, affect downstream genes, and modulate proliferation, apoptosis, tumor cell migration, and autophagy. ncRNAs can also induce cancer stem cell features and affect the epithelial-mesenchymal transition. Thus, ncRNAs could possibly act as new targets in chemotherapy combinations to treat GI cancer and to predict treatment response.

Dual-Network Collaborative Matrix Factorization for predicting small molecule-miRNA associations

MicroRNAs (miRNAs) play crucial roles in multiple biological processes and human diseases and can be considered as therapeutic targets of small molecules (SMs). Because biological experiments used to verify SM-miRNA associations are time-consuming and expensive, it is urgent to propose new computational models to predict new SM-miRNA associations. Here, we proposed a novel method called Dual-network Collaborative Matrix Factorization (DCMF) for predicting the potential SM-miRNA associations. Firstly, we utilized the Weighted K Nearest Known Neighbors (WKNKN) method to preprocess SM-miRNA association matrix. Then, we constructed matrix factorization model to obtain two feature matrices containing latent features of SM and miRNA, respectively. Finally, the predicted SM-miRNA association score matrix was obtained by calculating the inner product of two feature matrices. The main innovations of this method were that the use of WKNKN method can preprocess the missing values of association matrix and the introduction of dual network can integrate more diverse similarity information into DCMF. For evaluating the validity of DCMF, we implemented four different cross validations (CVs) based on two distinct datasets and two different case studies. Finally, based on dataset 1 (dataset 2), DCMF achieved Area Under receiver operating characteristic Curves (AUC) of 0.9868 (0.8770), 0.9833 (0.8836), 0.8377 (0.7591) and 0.9836 ± 0.0030 (0.8632 ± 0.0042) in global Leave-One-Out Cross Validation (LOOCV), miRNA-fixed local LOOCV, SM-fixed local LOOCV and 5-fold CV, respectively. For case studies, plenty of predicted associations have been confirmed by published experimental literature. Therefore, DCMF is an effective tool to predict potential SM-miRNA associations.

MiR-122 radiosensitize hepatocellular carcinoma cells by suppressing cyclin G1

PURPOSE

Emerging evidence has shown that radiotherapy is an effective treatment for hepatocellular carcinoma (HCC), Micro(mi)RNAs are involved in regulating radiosensitivity in many cancers. MiR-122 accounts for approximately 70% of all cloned miRNAs in the liver, but there are few reports about whether it is involved in regulating of radiosensitivity in HCC cells.

MATERIALS AND METHODS

HCC cells (HepG2 and Huh7) overexpressing miR-122 were constructed by transfecting them with lentiviral-miR-122. Then, their proliferation ability was analyzed by the MTT, and colony formation assays and a xenograft tumor model was used to detect their radiosensitivity. The expression of cyclin G1 mRNA and protein was detected by the quantitative real-time polymerase chain reaction and western blotting, respectively.

RESULTS

Overexpression of miR-122 inhibited the proliferation of, and radiosensitized HCC cells. Cyclin G1 mRNA and protein level were suppressed in HepG2 tumors overexpression miR-122.

CONCLUSION

MiR-122 may be useful as a potential radiosensitizer for HCC, and its mechanism is related to the regulation of cyclin G1.

The related miRNAs involved in doxorubicin resistance or sensitivity of various cancers: an update

Doxorubicin (DOX) is an effective chemotherapy agent against a wide variety of tumors. However, intrinsic or acquired resistance diminishes the sensitivity of cancer cells to DOX, which leads to a cancer relapse and treatment failure. Resolutions to this challenge includes identification of the molecular pathways underlying DOX sensitivity/resistance and the development of innovative techniques to boost DOX sensitivity. DOX is classified as a Topoisomerase II poison, which is cytotoxic to rapidly dividing tumor cells. Molecular mechanisms responsible for DOX resistance include effective DNA repair and resumption of cell proliferation, deregulated development of cancer stem cell and epithelial to mesenchymal transition, and modulation of programmed cell death. MicroRNAs (miRNAs) have been shown to potentiate the reversal of DOX resistance as they have gene-specific regulatory functions in DOX-responsive molecular pathways. Identifying the dysregulation patterns of miRNAs for specific tumors following treatment with DOX facilitates the development of novel combination therapies, such as nanoparticles harboring miRNA or miRNA inhibitors to eventually prevent DOX-induced chemoresistance. In this article, we summarize recent findings on the role of miRNAs underlying DOX sensitivity/resistance molecular pathways. Also, we provide latest strategies for utilizing deregulated miRNA patterns as biomarkers or miRNAs as tools to overcome chemoresistance and enhance patient's response to DOX treatment.

Circular RNA Pleiotrophin promotes carcinogenesis in glioma via regulation of microRNA-122/SRY-box transcription factor 6 axis

BACKGROUND

Circular RNAs (circRNAs) are recently identified as gene regulators in mammals and play important roles in carcinogenesis of cancer. For example, circRNA_PTN has been recognized as a biomarker of human cancer and is overexpressed in glioma. The molecular function of circRNA_PTN and its downstream targets in glioma, however, remains elusive.

METHODS

Quantitative polymerase chain reaction analysis was used to measure the expression of circular RNA pleiotrophin (circ_PTN) and miR-122. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, propidium iodide and Annexin-V/propidium iodide assay were performed to determine cell proliferation and apoptosis of glioma cells. Circular RNA Interactome and TargetScan were used to predict the potential microRNA targeting of circ_PTN and the potential targets of miR-122, respectively. Luciferase activity assay was used to validate these interactions. Downstream molecular mechanisms, including SRY-box transcription factor 6 (SOX6), extracellular regulated protein kinases (ERK), Cyclin D1, B-cell lymphoma-2 (BCL-2) and BCL2 associated X, apoptosis regulator (BAX), were determined by western blot.

RESULTS

Circ_PTN was overexpressed in glioma cells, and its knockdown induced cell proliferation inhibition, cell cycle arrest and apoptosis in glioma cells. The target microRNA of circ_PTN was predicted to be miR-122, the expression of which was negatively correlated with circ_PTN in glioma cells. Moreover, SOX6 was predicted as a potential target of miR-122, and miR-122 overexpression decreased SOX6 expression. MiR-122 inhibitor reversed the tumor-suppressing effects of circ_PTN knockdown, while overexpression of SOX6 impaired the miR-122 overexpression-induced cell growth inhibition and apoptosis. In addition, mitogen activated kinase-like protein (MAPK)/ERK pathway was involved in circ_PTN/miR-122/SOX6 axis.

CONCLUSIONS

Circ_PTN acted as a sponge of miR-122 and upregulated miR-122 target SOX6, thus promoting carcinogenesis of glioma cells.

Current Implications of microRNAs in Genome Stability and Stress Responses of Ovarian Cancer

Genomic alterations and aberrant DNA damage signaling are hallmarks of ovarian cancer (OC), the leading cause of mortality among gynecological cancers worldwide. Owing to the lack of specific symptoms and late-stage diagnosis, survival chances of patients are significantly reduced. Poly (ADP-ribose) polymerase (PARP) inhibitors and replication stress response inhibitors present attractive therapeutic strategies for OC. Recent research has focused on ovarian cancer-associated microRNAs (miRNAs) that play significant regulatory roles in various cellular processes. While miRNAs have been shown to participate in regulation of tumorigenesis and drug responses through modulating the DNA damage response (DDR), little is known about their potential influence on sensitivity to chemotherapy. The main objective of this review is to summarize recent findings on the utility of miRNAs as cancer biomarkers, in particular, ovarian cancer, and their regulation of DDR or modified replication stress response proteins. We further discuss the suppressive and promotional effects of various miRNAs on ovarian cancer and their participation in cell cycle disturbance, response to DNA damage, and therapeutic functions in multiple cancer types, with particular focus on ovarian cancer. Improved understanding of the mechanisms by which miRNAs regulate drug resistance should facilitate the development of effective combination therapies for ovarian cancer.

Anti-miR-518d-5p overcomes liver tumor cell death resistance through mitochondrial activity

Dysregulation of miRNAs is a hallmark of cancer, modulating oncogenes, tumor suppressors, and drug responsiveness. The multi-kinase inhibitor sorafenib is one of the first-line drugs for advanced hepatocellular carcinoma (HCC), although the outcome for treated patients is heterogeneous. The identification of predictive biomarkers and targets of sorafenib efficacy are sorely needed. Thus, selected top upregulated miRNAs from the C19MC cluster were analyzed in different hepatoma cell lines compared to immortalized liver human cells, THLE-2 as control. MiR-518d-5p showed the most consistent upregulation among them. Thus, miR-518d-5p was measured in liver tumor/non-tumor samples of two distinct cohorts of HCC patients (n = 16 and n = 20, respectively). Circulating miR-518d-5p was measured in an independent cohort of HCC patients receiving sorafenib treatment (n = 100), where miR-518d-5p was analyzed in relation to treatment duration and patient's overall survival. In vitro and in vivo studies were performed in human hepatoma BCLC3 and Huh7 cells to analyze the effect of miR-518d-5p inhibition/overexpression during the response to sorafenib. Compared with healthy individuals, miR-518d-5p levels were higher in hepatic and serum samples from HCC patients (n = 16) and in an additional cohort of tumor/non-tumor paired samples (n = 20). MiR-518d-5p, through the inhibition of c-Jun and its mitochondrial target PUMA, desensitized human hepatoma cells and mouse xenograft to sorafenib-induced apoptosis. Finally, serum miR-518d-5p was assessed in 100 patients with HCC of different etiologies and BCLC-stage treated with sorafenib. In BCLC-C patients, higher serum miR-518d-5p at diagnosis was associated with shorter sorafenib treatment duration and survival. Hence, hepatic miR-518d-5p modulates sorafenib resistance in HCC through inhibition of c-Jun/PUMA-induced apoptosis. Circulating miR-518d-5p emerges as a potential lack of response biomarker to sorafenib in BCLC-C HCC patients.

HCV Proteins Modulate the Host Cell miRNA Expression Contributing to Hepatitis C Pathogenesis and Hepatocellular Carcinoma Development

Simple Summary

According to the last estimate by the World Health Organization (WHO), more than 71 million individuals have chronic hepatitis C worldwide. The persistence of HCV infection leads to chronic hepatitis, which can evolve into liver cirrhosis and ultimately into hepatocellular carcinoma (HCC). Although the pathogenic mechanisms are not fully understood, it is well established that an interplay between host cell factors, including microRNAs (miRNA), and viral components exist in all the phases of the viral infection and replication. Those interactions establish a complex equilibrium between host cells and HCV and participate in multiple mechanisms characterizing hepatitis C pathogenesis. The present review aims to describe the role of HCV structural and non-structural proteins in the modulation of cellular miRNA during HCV infection and pathogenesis.

Abstract

Hepatitis C virus (HCV) genome encodes for one long polyprotein that is processed by cellular and viral proteases to generate 10 polypeptides. The viral structural proteins include the core protein, and the envelope glycoproteins E1 and E2, present at the surface of HCV particles. Non-structural (NS) proteins consist of NS1, NS2, NS3, NS4A, NS4B, NS5a, and NS5b and have a variable function in HCV RNA replication and particle assembly. Recent findings evidenced the capacity of HCV virus to modulate host cell factors to create a favorable environment for replication. Indeed, increasing evidence has indicated that the presence of HCV is significantly associated with aberrant miRNA expression in host cells, and HCV structural and non-structural proteins may be responsible for these alterations. In this review, we summarize the recent findings on the role of HCV structural and non-structural proteins in the modulation of host cell miRNAs, with a focus on the molecular mechanisms responsible for the cell re-programming involved in viral replication, immune system escape, as well as the oncogenic process. In this regard, structural and non-structural proteins have been shown to modulate the expression of several onco-miRNAs or tumor suppressor miRNAs.

Sustained and targeted delivery of siRNA/DP7-C nanoparticles from injectable thermosensitive hydrogel for hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC) is one of the most lethal cancers in humans. The inhibition of peptidyl‐prolyl cis/trans isomerase (Pin1) gene expression may have great potential in the treatment of HCC. N‐Acetylgalactosamine (GalNAc) was used to target the liver. Cholesterol‐modified antimicrobial peptide DP7 (DP7‐C) acts as a carrier, the GalNAc‐siRNA/DP7‐C complex increases the uptake of GalNAc‐siRNA and the escape of endosomes in hepatocytes. In addition, DP7‐C nanoparticles and hydrogel‐assisted GalNAc‐Pin1 siRNA delivery can effectively enhance the stability and prolong the silencing effects of Pin1 siRNA. In an orthotopic liver cancer model, the GalNAc‐Pin1 siRNA/DP7‐C/hydrogel complex can potentially regulate Pin1 expression in hepatocellular carcinoma cells and effectively inhibit tumor progression. Our study proves that Pin1 siRNA is an efficient method for the treatment of HCC and provides a sustainable and effective drug delivery system for the suppression of liver cancer.

The Epigenetic Modulation of Cancer and Immune Pathways in Hepatitis B Virus-Associated Hepatocellular Carcinoma: The Influence of HBx and miRNA Dysregulation

Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HBV-HCC) pathogenesis is fueled by persistent HBV infection that stealthily maintains a delicate balance between viral replication and evasion of the host immune system. HBV is remarkably adept at using a combination of both its own, as well as host machinery to ensure its own replication and survival. A key tool in its arsenal, is the HBx protein which can manipulate the epigenetic landscape to decrease its own viral load and enhance persistence, as well as manage host genome epigenetic responses to the presence of viral infection. The HBx protein can initiate epigenetic modifications to dysregulate miRNA expression which, in turn, can regulate downstream epigenetic changes in HBV-HCC pathogenesis. We attempt to link the HBx and miRNA induced epigenetic modulations that influence both the HBV and host genome expression in HBV-HCC pathogenesis. In particular, the review investigates the interplay between CHB infection, the silencing role of miRNA, epigenetic change, immune system expression and HBV-HCC pathogenesis. The review demonstrates exactly how HBx-dysregulated miRNA in HBV-HCC pathogenesis influence and are influenced by epigenetic changes to modulate both viral and host genome expression. In particular, the review identifies a specific subset of HBx induced epigenetic miRNA pathways in HBV-HCC pathogenesis demonstrating the complex interplay between HBV infection, epigenetic change, disease and immune response. The wide-ranging influence of epigenetic change and miRNA modulation offers considerable potential as a therapeutic option in HBV-HCC.

Therapeutic strategies for miRNA delivery to reduce hepatocellular carcinoma

Malignancies of hepatocellular carcinoma (HCC) are rapidly spreading and commonly fatal. Like most cancers, the gene expression patterns in HCC vary significantly from patient to patient. Moreover, the expression networks during HCC progression are largely controlled by microRNAs (miRNAs) regulating multiple oncogenes and tumor supressors. Therefore, miRNA-based therapeutic strategies altering these networks may significantly influence the cellular behavior enough for them to cure HCC. However, the most substantial challenges in developing such therapies are the stability of the oligos themselves and that of their delivery systems. Here we provide a comprehensive update describing various miRNA delivery systems, including virus-based delivery and non-viral delivery. The latter may be achieved using inorganic nanoparticles, polymer based nano-carriers, lipid-based vesicles, exosomes, and liposomes. Leaky vasculature in HCC-afflicted livers helps untargeted nanocarriers to accumulate in the tumor tissue but may result in side effects during higher dose of treatment. On the other hand, the strategies for actively targeting miRNA therepeutics to cancerous cells through nano-conjugates or vesicles by decorating their surface with antibodies against or ligands for HCC-specific antigens or receptors are more efficient in preventing damage to healthy tissue and cancer recurrence.

Preferentially released miR-122 from cyclodextrin-based star copolymer nanoparticle enhances hepatoma chemotherapy by apoptosis induction and cytotoxics efflux inhibition

Chemotherapy, as one of the most commonly used treatment modalities for cancer therapy, provides limited benefits to hepatoma patients, owing to its inefficient delivery as well as the intrinsic chemo-resistance of hepatoma. Bioinformatic analysis identified the therapeutic role of a liver-specific microRNA — miR-122 for enhancing chemo-therapeutic efficacy in hepatoma. Herein, a cyclodextrin-cored star copolymer nanoparticle system (sCDP/DOX/miR-122) is constructed to co-deliver miR-122 with doxorubicin (DOX) for hepatoma therapy. In this nanosystem, miR-122 is condensed by the outer cationic poly (2-(dimethylamino) ethyl methacrylate) chains of sCDP while DOX is accommodated in the inner hydrophobic cyclodextrin cavities, endowing a sequential release manner of miR-122 and DOX. The preferentially released miR-122 not only directly induces cell apoptosis by down regulation of Bcl-w and enhanced p53 activity, but also increases DOX accumulation through inhibiting cytotoxic efflux transporter expression, which realizes synergistic performance on cell inhibition. Moreover, sCDP/DOX/miR-122 displays remarkably increased anti-tumor efficacy in vivo compared to free DOX and sCDP/DOX alone, indicating its great promising in hepatoma therapy.

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Cyclodextrin-based polymeric nanoparticle was developed to co-deliver miR-122 and doxorubicin.

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The nanoparticle sequentially released miR-122 and doxorubicin into HepG2 cells.

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The preferentially released miR-122 induces cell apoptosis and inhibits doxorubicin efflux.

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Enhanced anti-tumor effects with reduced cardiotoxicity were achieved in vivo.

Notch Signaling Regulation in HCC: From Hepatitis Virus to Non-Coding RNAs

The Notch family includes evolutionary conserved genes that encode for single-pass transmembrane receptors involved in stem cell maintenance, development and cell fate determination of many cell lineages. Upon activation by different ligands, and depending on the cell type, Notch signaling plays pleomorphic roles in hepatocellular carcinoma (HCC) affecting neoplastic growth, invasion capability and stem like properties. A specific knowledge of the deregulated expression of each Notch receptor and ligand, coupled with resultant phenotypic changes, is still lacking in HCC. Therefore, while interfering with Notch signaling might represent a promising therapeutic approach, the complexity of Notch/ligands interactions and the variable consequences of their modulations raises concerns when performed in undefined molecular background. The gamma-secretase inhibitors (GSIs), representing the most utilized approach for Notch inhibition in clinical trials, are characterized by important adverse effects due to the non-specific nature of GSIs themselves and to the lack of molecular criteria guiding patient selection. In this review, we briefly summarize the mechanisms involved in Notch pathway activation in HCC supporting the development of alternatives to the γ-secretase pan-inhibitor for HCC therapy.

miR-21 inhibition reverses doxorubicin-resistance and inhibits PC3 human prostate cancer cells proliferation

Many approaches have been examined to reversing multidrug resistance (MDR), but sub-optimal target-based strategies have limited their efficacy. Herein, we investigate microRNA (miR-21) suppression on the doxorubicin (DOX)-sensitisation of the DOX-resistant (PC3/DOX) cell line in prostate cancer (PCa). Expression levels of miR-21, P-glycoprotein (P-gp), MDR-1 and PTEN evaluated in PC3/DOX cancer cells by qRT-PCR and western blot analyses. The cytotoxic effects of transfected of miR-21 were assessed by MTT assay for 72 hr. Rhodamine123 (Rh123) assay was employed to define the activity of P-gp. Apoptosis was detected by Flow cytometry. As expected, miR-21 was expressed highly in PC3/DOX cells (p < 0.05). It was shown that miRNA-21 suppression considerably hindered PC3/DOX cell viability. miR-21 suppression dramatically downregulated P-gp expression and activity in DOX-resistance cells and abolished MDR by an increment of intracellular accumulation of DOX in PC3/DOX cells (p < 0.05). PTEN is a key modulator of the PI3K/Akt/P-gp cascade, which miR-21 suppression led to the upregulation of PTEN and sequentially lower-expression of P-gp that reversed MDR. Also, miR-21 repression enhanced the apoptosis rate of PC3/DOX cells. The findings of this paper contribute to the current understanding of the functions of miR-21 in MDR-reversing in PCa.

Signaling pathways in hepatocellular carcinoma

Despite the recent introduction of new effective systemic agents, the survival of patients with hepatocellular carcinoma (HCC) at advanced stages remains dismal. This underscores the need for new therapies, which has spurred extensive research on the identification of the main drivers of pathway de-regulation as a source of novel therapeutic targets. Frequently altered pathways in HCC involve growth factor receptors (e.g., VEGFR, FGFR, TGFA, EGFR, IGFR) and/or its cytoplasmic intermediates (e.g., PI3K-AKT-mTOR, RAF/ERK/MAPK) as well as key pathways in cell differentiation (e.g., Wnt/β-catenin, JAK/STAT, Hippo, Hedgehog, Notch). Somatic mutations, chromosomal aberrations and epigenetic changes are common mechanisms for pathway deregulation in HCC. Aberrant pathway activation has also been explored as a biomarker to predict response to specific therapies, but currently, these strategies are not implemented when deciding systemic therapies in HCC patients. Beyond the well-established molecular cascades, there are numerous emerging signaling pathways also deregulated in HCC (e.g., tumor microenvironment, non-coding RNA, intestinal microbiota), which have opened new avenues for therapeutic exploration.

Design of an Interferon-Resistant Oncolytic HSV-1 Incorporating Redundant Safety Modalities for Improved Tolerability

Development of next-generation oncolytic viruses requires the design of vectors that are potently oncolytic, immunogenic in human tumors, and well tolerated in patients. Starting with a joint-region deleted herpes simplex virus 1 (HSV-1) to create large transgene capability, we retained a single copy of the ICP34.5 gene, introduced mutations in UL37 to inhibit retrograde axonal transport, and inserted cell-type-specific microRNA (miRNA) target cassettes in HSV-1 genes essential for replication or neurovirulence. Ten miRNA candidates highly expressed in normal tissues and with low or absent expression in malignancies were selected from a comprehensive profile of 800 miRNAs with an emphasis on protection of the nervous system. Among the genes essential for viral replication identified using a small interfering RNA (siRNA) screen, we selected ICP4, ICP27, and UL8 for miRNA attenuation where a single miRNA is sufficient to potently attenuate viral replication. Additionally, a neuron-specific miRNA target cassette was introduced to control ICP34.5 expression. This vector is resistant to type I interferon compared to ICP34.5-deleted oncolytic HSVs, and in cancer cell lines, the oncolytic activity of the modified vector is equivalent to its parental virus. In vivo, this vector potently inhibits tumor growth while being well tolerated, even at high intravenous doses, compared to parental wild-type HSV-1.

Dysregulated microRNAs in Hepatitis B Virus-Related Hepatocellular Carcinoma: Potential as Biomarkers and Therapeutic Targets

MicroRNAs (miRNAs) are non-coding small RNAs that can function as gene regulators and are involved in tumorigenesis. We review the commonly dysregulated miRNAs in liver tumor tissues and plasma/serum of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) patients. The frequently reported up-regulated miRNAs in liver tumor tissues include miR-18a, miR-21, miR-221, miR-222, and miR-224, whereas down-regulated miRNAs include miR-26a, miR-101, miR-122, miR-125b, miR-145, miR-199a, miR-199b, miR-200a, and miR-223. For a subset of these miRNAs (up-regulated miR-222 and miR-224, down-regulated miR-26a and miR-125b), the pattern of dysregulated circulating miRNAs in plasma/serum is mirrored in tumor tissue based on multiple independent studies. Dysregulated miRNAs target oncogenes or tumor suppressor genes involved in hepatocarcinogenesis. Normalization of dysregulated miRNAs by up- or down-regulation has been shown to inhibit HCC cell proliferation or sensitize liver cancer cells to chemotherapeutic treatment. miRNAs hold as yet unrealized potential as biomarkers for early detection of HCC and as precision therapeutic targets, but further studies in diverse populations and across all stages of HCC are needed.

The Multiple Roles of Hepatitis B Virus X Protein (HBx) Dysregulated MicroRNA in Hepatitis B Virus-Associated Hepatocellular Carcinoma (HBV-HCC) and Immune Pathways

Currently, the treatment of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) [HBV-HCC] relies on blunt tools that are unable to offer effective therapy for later stage pathogenesis. The potential of miRNA to treat HBV-HCC offer a more targeted approach to managing this lethal carcinoma; however, the complexity of miRNA as an ancillary regulator of the immune system remains poorly understood. This review examines the overlapping roles of HBx-dysregulated miRNA in HBV-HCC and immune pathways and seeks to demonstrate that specific miRNA response in immune cells is not independent of their expression in hepatocytes. This interplay between the two pathways may provide us with the possibility of using candidate miRNA to manipulate this interaction as a potential therapeutic option.

Non-Coding RNAs: Regulating Disease Progression and Therapy Resistance in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the primary liver cancer arising from hepatocytes, is a universal health problem and one of the most common malignant tumors. Surgery followed by chemotherapy as well as tyrosine kinase inhibitors (TKIs), such as sorafenib, are primary treatment procedures for HCC, but recurrence of disease because of therapy resistance results in high mortality. It is necessary to identify novel regulators of HCC for developing effective targeted therapies that can significantly interfere with progression of the disease process. Non-coding RNAs (ncRNAs) are an abundant group of versatile RNA transcripts that do not translate into proteins, rather serve as potentially functional RNAs. The role of ncRNAs in regulating diverse aspects of the carcinogenesis process are gradually being elucidated. Recent advances in RNA sequencing technology have identified a plethora of ncRNAs regulating all aspects of hepatocarcinogenesis process and serving as potential prognostic or diagnostic biomarkers. The present review provides a comprehensive description of the biological roles of ncRNAs in disease process and therapy resistance, and potential clinical application of these ncRNAs in HCC.

Atypical cyclins in cancer: New kids on the block?

Atypical cyclins have recently emerged as a new subfamily of cyclins characterized by common structural features and interactor pattern. Interestingly, atypical cyclins are phylogenetically close to canonical cyclins, which have well-established roles in cell cycle regulation and cancer. Therefore, although the function of atypical cyclins is still poorly characterized, it seems likely that they are involved in cancer pathogenesis as well. Here, we coupled gene expression and prognostic significance analysis to bibliographic search in order to provide new insights into the role of atypical cyclins in cancer. The information gathered suggests that atypical cyclins intervene in critical processes to sustain cancer growth and have potential to become novel prognostic markers and drug targets in cancer.

Physical and chemical template-blocking strategies in the exponential amplification reaction of circulating microRNAs

The detection of circulating miRNA through isothermal amplification wields many attractive advantages over traditional methods, such as reverse transcription RT-qPCR. However, it is challenging to control the background signal produced in the absence of target, which severely hampers applications of such methods for detecting low abundance targets in complex biological samples. In the present work, we employed both the cobalt oxyhydroxide (CoOOH) nanoflakes and the chemical modification of hexanediol to block non-specific template elongation in exponential amplification reaction (EXPAR). Adsorption by the CoOOH nanoflakes and the hexanediol modification at the 3' end effectively prevented no-target polymerization on the template itself and thus greatly improved the performance of EXPAR, detecting as low as 10 aM of several miRNA targets, including miR-16, miR-21, and miR-122, with the fluorescent DNA staining dye of SYBR Gold™. Little to no cross-reactivity was observed from the interfering strands present in 10-fold excess. Besides contributing to background reduction, the CoOOH nanoflakes strongly adsorbed nucleic acids and isolated them from a complex sample matrix, thus permitting successful detection of the target miRNA in the serum. We expect that simple but sensitive template-blocking EXPAR could be a valuable tool to help with the discovery and validation of miRNA markers in biospecimens. Graphical abstract.

MiR-30e-3p Influences Tumor Phenotype through MDM2/TP53 Axis and Predicts Sorafenib Resistance in Hepatocellular Carcinoma

The molecular background of hepatocellular carcinoma (HCC) is highly heterogeneous, and biomarkers predicting response to treatments are an unmet clinical need. We investigated miR-30e-3p contribution to HCC phenotype and response to sorafenib, as well as the mutual modulation of TP53/MDM2 pathway, in HCC tissues and preclinical models. MiR-30e-3p was downregulated in human and rat HCCs, and its downregulation associated with TP53 mutations. TP53 contributed to miR-30e-3p biogenesis, and MDM2 was identified among its target genes, establishing an miR-30e-3p/TP53/MDM2 feedforward loop and accounting for miR-30e-3p dual role based on TP53 status. EpCAM, PTEN, and p27 were demonstrated as miR-30e-3p additional targets mediating its contribution to stemness and malignant features. In a preliminary cohort of patients with HCC treated with sorafenib, increased miR-30e-3p circulating levels predicted the development of resistance. In conclusion, molecular background dictates miR-30e-3p dual behavior in HCC. Mdm2 targeting plays a predominant tumor suppressor function in wild-type TP53 contexts, whereas other targets such as PTEN, p27, and EpCAM gain relevance and mediate miR-30e-3p oncogenic role in nonfunctional TP53 backgrounds. Increased circulating levels of miR-30e-3p predict the development of sorafenib resistance in a preliminary series of patients with HCC and deserve future investigations. SIGNIFICANCE: The dual role of miR-30e-3p in HCC clarifies how the molecular context dictates the tumor suppressor or oncogenic function played by miRNAs.