Combining miR-10b-Targeted Nanotherapy with Low-Dose Doxorubicin Elicits Durable Regressions of Metastatic Breast Cancer

Imaging of Endometriotic Lesions Using cRGD-MN Probe in a Mouse Model of Endometriosis

Approximately 10% of women suffer from endometriosis during their reproductive years. This disease is a chronic debilitating condition whose etiology for lesion implantation and survival heavily relies on adhesion and angiogenic factors. Currently, there are no clinically approved agents for its detection. In this study, we evaluated cRGD-peptide-conjugated nanoparticles (RGD-Cy5.5-MN) to detect lesions using magnetic resonance imaging (MRI) in a mouse model of endometriosis. We utilized a luciferase-expressing murine suture model of endometriosis. Imaging was performed before and after 24 h following the intravenous injection of RGD-Cy5.5-MN or control nanoparticles (Cy5.5-MN). Next, we performed biodistribution of RGD-Cy5.5-MN and correlative fluorescence microscopy of lesions stained for CD34. Tissue iron content was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Our results demonstrated that targeting endometriotic lesions with RGD-Cy5.5-MN resulted in a significantly higher delta T2* upon its accumulation compared to Cy5.5-MN. ICP-OES showed significantly higher iron content in the lesions of the animals in the experimental group compared to the lesions of the animals in the control group. Histology showed colocalization of Cy5.5 signal from RGD-Cy5.5-MN with CD34 in the lesions pointing to the targeted nature of the probe. This work offers initial proof-of-concept for targeting angiogenesis in endometriosis which can be useful for potential clinical diagnostic and therapeutic approaches for treating this disease.

Co-administration of temozolomide (TMZ) and the experimental therapeutic targeting miR-10b, profoundly affects the tumorigenic phenotype of human glioblastoma cells

Introduction: Recent studies have shown that miRNA-10b is highly expressed in high-grade glioblastoma multiforme (GBM), and its inhibition leads to deregulation of multiple pathways in tumorigenesis, resulting in repression of tumor growth and increased apoptosis. Thus, we hypothesized that suppressing miR-10b could enhance the cytotoxicity of conventional GBM chemotherapy with temozolomide (TMZ). Methods: Inhibition of miR-10b in glioblastoma cells was achieved using an experimental therapeutic consisting of anti-miR10b antagomirs conjugated to iron oxide nanoparticles (termed MN-anti-miR10b). The nanoparticles serve as delivery vehicles for the antagomirs as well as imaging reporters guiding the delivery in future animal studies. Results: Treatment of U251 and LN229 human glioblastoma cells with MN-anti-miR10b led to inhibition of miR-10b accompanied by repression of growth and increase in apoptosis. We next explored whether MN-anti-miR10b could enhance the cytotoxic effect of TMZ. During these studies, we unexpectedly found that TMZ monotherapy increased miR-10b expression and changed the expression of corresponding miR-10b targets. This discovery led to the design of a sequence-dependent combination treatment, in which miR-10b inhibition and induction of apoptosis by MN-anti-miR10b was followed by a sub-therapeutic dose of TMZ, which caused cell cycle arrest and ultimately cell death. This combination was highly successful in significant enhancement of apoptosis and decrease in cell migration and invasiveness. Discussion: Considering the unexpected effects of TMZ on miR-10b expression and possible implications on its clinical application, we reasoned that comprehensive in vitro studies were warranted before embarking on studies in animals. These intriguing findings serve as a solid foundation for future in vivo studies and offer promise for the successful treatment of GBM.

An Overview of the Role of MicroRNAs on Carcinogenesis: A Focus on Cell Cycle, Angiogenesis and Metastasis

In recent years, the importance of epigenetic markers in the carcinogenesis of different malignant neoplasms has been demonstrated, also demonstrating their utility for understanding metastatic spread and tumor progression in cancer patients. Among the different biomarkers, microRNAs represent a set of non-coding RNAs that regulate gene expression, having been involved in a wide variety of neoplasia acting in different oncogenic pathways. Both the overexpression and downregulation of microRNAs represent a complex interaction with various genes whose ultimate consequence is increased cell proliferation, tumor invasion and interaction with various driver markers. It should be noted that in current clinical practice, even though the combination of different microRNAs has been shown to be useful by different authors at diagnostic and prognostic levels, there are no diagnostic kits that can be used for the initial approach or to assess recurrences of oncological diseases. Previous works have cited microRNAs as having a critical role in several carcinogenic mechanisms, ranging from cell cycle alterations to angiogenesis and mechanisms of distant metastatic dissemination. Indeed, the overexpression or downregulation of specific microRNAs seem to be tightly involved in the modulation of various components related to these processes. For instance, cyclins and cyclin-dependent kinases, transcription factors, signaling molecules and angiogenic/antiangiogenic products, among others, have been recognized as specific targets of microRNAs in different types of cancer. Therefore, the purpose of this article is to describe the main implications of different microRNAs in cell cycle alterations, metastasis and angiogenesis, trying to summarize their involvement in carcinogenesis.

Harnessing Epigenetics for Breast Cancer Therapy: The Role of DNA Methylation, Histone Modifications, and MicroRNA

Breast cancer exhibits various epigenetic abnormalities that regulate gene expression and contribute to tumor characteristics. Epigenetic alterations play a significant role in cancer development and progression, and epigenetic-targeting drugs such as DNA methyltransferase inhibitors, histone-modifying enzymes, and mRNA regulators (such as miRNA mimics and antagomiRs) can reverse these alterations. Therefore, these epigenetic-targeting drugs are promising candidates for cancer treatment. However, there is currently no effective epi-drug monotherapy for breast cancer. Combining epigenetic drugs with conventional therapies has yielded positive outcomes and may be a promising strategy for breast cancer therapy. DNA methyltransferase inhibitors, such as azacitidine, and histone deacetylase inhibitors, such as vorinostat, have been used in combination with chemotherapy to treat breast cancer. miRNA regulators, such as miRNA mimics and antagomiRs, can alter the expression of specific genes involved in cancer development. miRNA mimics, such as miR-34, have been used to inhibit tumor growth, while antagomiRs, such as anti-miR-10b, have been used to inhibit metastasis. The development of epi-drugs that target specific epigenetic changes may lead to more effective monotherapy options in the future.

Remodeling the tumor immune microenvironment with oncolytic viruses expressing miRNAs

MiRNAs (miRNA, miR) play important functions in the tumor microenvironment (TME) by silencing gene expression through RNA interference. They are involved in regulating both tumor progression and tumor suppression. The pathways involved in miRNA processing and the miRNAs themselves are dysregulated in cancer. Consequently, they have become attractive therapeutic targets as underscored by the plethora of miRNA-based therapies currently in pre-clinical and clinical studies. It has been shown that miRNAs can be used to improve oncolytic viruses (OVs) and enable superior viral oncolysis, tumor suppression and immune modulation. In these cases, miRNAs are empirically selected to improve viral oncolysis, which translates into decreased tumor growth in multiple murine models. While this infectious process is critical to OV therapy, optimal immunomodulation is crucial for the establishment of a targeted and durable effect, resulting in cancer eradication. Through numerous mechanisms, OVs elicit a strong antitumor immune response that can also be further improved by miRNAs. They are known to regulate components of the immune TME and promote effector functions, antigen presentation, phenotypical polarization, and varying levels of immunosuppression. Reciprocally, OVs have the power to overcome the limitations encountered in canonical miRNA-based therapies. They deliver therapeutic payloads directly into the TME and facilitate their amplification through selective tumoral tropism and abundant viral replication. This way, off-target effects can be minimized. This review will explore the ways in which miRNAs can synergistically enhance OV immunotherapy to provide the basis for future therapeutics based on this versatile combination platform.

Tumor-derived miRNAs as tumor microenvironment regulators for synergistic therapeutic options

MicroRNAs (miRNAs) are a class of non-coding RNAs that perform post-transcriptional gene regulation. This review focuses on the role of tumor cell-derived miRNAs in the regulation of the tumor microenvironment (TME) via receptor cell recoding, including angiogenesis, expression of immunosuppressive molecules, formation of radiation resistance, and chemoresistance. Furthermore, we discuss the potential of these molecules as adjuvant therapies in combination with chemotherapy, radiotherapy, or immunotherapy, as well as their advantages as efficacy predictors for personalized therapy. MiRNA-based therapeutic agents for tumors are currently in clinical trials, and while challenges remain, additional research on tumor-derived miRNAs is warranted, which may provide significant clinical benefits to cancer patients.

miRNA Theranostic Nanoparticles Promote Pancreatic Beta Cell Proliferation in Type 1 Diabetes Model

Type 1 diabetes (T1D) is a chronic autoimmune disorder which affects the insulin-producing beta cells in the pancreas. A variety of strategies, namely, insulin replacement therapy, engineered vaccines, immunomodulators, etc., have been explored to correct this condition. Recent studies have attributed the development of T1D to the anomalous expression of microRNAs in the pancreatic islets. Here, we describe the protocol for the development of a theranostic approach to modify the expression of aberrant miRNAs. The MRI-based nanodrug consists of superparamagnetic iron oxide nanoparticles conjugated to microRNA-targeting oligonucleotides that can promote proliferation of pancreatic beta cells in a mouse model of T1D. This theranostic approach can successfully serve as a potential therapeutic approach for the targeted treatment of T1D with minimal side effects.

Case report: MicroRNA-10b as a therapeutic target in feline metastatic mammary carcinoma and its implications for human clinical trials

Ninety percent of deaths from cancer are caused by metastasis. miRNAs are critical players in biological processes such as proliferation, metastasis, apoptosis, and self-renewal. We and others have previously demonstrated that miRNA-10b promotes metastatic cell migration and invasion. Importantly, we also showed that miR-10b is a critical driver of metastatic cell viability and proliferation. To treat established metastases by inhibiting miR-10b, we utilized a therapeutic, termed MN-anti-miR10b, composed of anti-miR-10b antagomirs, conjugated to iron oxide nanoparticles, that serve as delivery vehicles to tumor cells in vivo and a magnetic resonance imaging (MRI) reporter. In our previous studies using murine models of metastatic breast cancer, we demonstrated the effectiveness of MN-anti-miR10b in preventing and eliminating existing metastases. With an outlook toward clinical translation of our therapeutic, here we report studies in large animals (companion cats) with spontaneous feline mammary carcinoma (FMC). We first investigated the expression and tissue localization of miR-10b in feline tumors and metastases and showed remarkable similarity to these features in humans. Next, in the first case study involving this therapeutic we intravenously dosed an FMC patient with MN-anti-miR10b and demonstrated its delivery to the metastatic lesions using MRI. We also showed the initial safety profile of the therapeutic and demonstrated significant change in miR-10b expression and its target HOXD10 after dosing. Our results provide support for using companion animals for further MN-anti-miR10b development as a therapy and serve as a guide for future clinical trials in human patients.

Clinical Applications of Short Non-Coding RNA-Based Therapies in the Era of Precision Medicine

Simple Summary

RNA-based drugs are an attractive approach for personalized treatment of cancer and other diseases. This review focuses on two related classes of short non-coding RNA: microRNAs (miRNAs) and small interfering RNAs (siRNAs). miRNAs are endogenous short RNAs that bind multiple messenger RNAs (mRNAs) and prevent the production of their gene-products, whereas siRNAs are exogenous RNAs that target a single and specific mRNA for degradation. This review describes the development, challenges, and clinical successes of short RNA-based drugs. We provide several examples of how these RNA drugs are designed, chemically modified and delivered for treatment of different cancer types, cardiovascular disease, and rare genetic disorders. We highlight the similarities, differences, and considerations to maximize the treatment efficacy of miRNA-based vs. siRNA-based drugs.

Abstract

Traditional targeted therapeutic agents have relied on small synthetic molecules or large proteins, such as monoclonal antibodies. These agents leave a lot of therapeutic targets undruggable because of the lack or inaccessibility of active sites and/or pockets in their three-dimensional structure that can be chemically engaged. RNA presents an attractive, transformative opportunity to reach any genetic target with therapeutic intent. RNA therapeutic design is amenable to modularity and tunability and is based on a computational blueprint presented by the genetic code. Here, we will focus on short non-coding RNAs (sncRNAs) as a promising therapeutic modality because of their potency and versatility. We review recent progress towards clinical application of small interfering RNAs (siRNAs) for single-target therapy and microRNA (miRNA) activity modulators for multi-target therapy. siRNAs derive their potency from the fact that the underlying RNA interference (RNAi) mechanism is catalytic and reliant on post-transcriptional mRNA degradation. Therapeutic siRNAs can be designed against virtually any mRNA sequence in the transcriptome and specifically target a disease-causing mRNA variant. Two main classes of microRNA activity modulators exist to increase (miRNA mimics) or decrease (anti-miRNA inhibitors) the function of a specific microRNA. Since a single microRNA regulates the expression of multiple target genes, a miRNA activity modulator can have a more profound effect on global gene expression and protein output than siRNAs do. Both types of sncRNA-based drugs have been investigated in clinical trials and some siRNAs have already been granted FDA approval for the treatment of genetic, cardiometabolic, and infectious diseases. Here, we detail clinical results using siRNA and miRNA therapeutics and present an outlook for the potential of these sncRNAs in medicine.

Diagnostic, grading and prognostic role of a restricted miRNAs signature in primary and metastatic brain tumours. Discussion on their therapeutic perspectives

At present, brain tumours remain one of the "hard-to-treat" malignancies with minimal improvement in patients' survival. Recently, miRNAs have been shown to correlate with oncogenesis and metastasis and have been investigated as potential biomarkers for diagnosis, prognosis and therapy prediction in different brain malignancies. The aim of the current study was to select an accurate and affordable brain tumour detection and grading approach. In the present study, we analysed the applicability of a restricted miRNA signature that could differentiate among patients with primary as well as metastatic brain tumours. Fresh tumour tissues were collected from Bulgarian patients (n = 38), including high-grade gliomas (n = 23), low-grade gliomas (n = 10) and brain metastases (n = 5) from lung cancer. Total RNAs enriched with microRNAs were isolated and differentially expressed miRNAs were analyzed by RT-qPCR using TaqMan Advanced miRNA assay. We selected a signature of miR-21, miR-10b, miR-7, miR-491 that showed good diagnostic potential in high-grade gliomas, low-grade gliomas and brain metastases compared with normal brain tissues. Our results showed that miR-10b could reliably differentiate brain metastases from high-grade gliomas, while miR-491 could distinguish low-grade from high-grade gliomas and brain metastases from low-grade gliomas. We observed that miR-21 and miR-7 correlated with disease recurrence, survival status and the Karnofsky Performance Status. The selected signature of miR-7, miR-21, miR-10b and miR-491 could be used as a highly accurate diagnostic, grading and prognostic biomarker in differentiating various types of brain tumours. Our data suggest that the 4-miRNAs signature could be further analysed for predicting treatment response and for future miRs-based targeted therapy. The ongoing studies on miRs-based targeted therapy related to our selected miRNA signature are also reviewed.

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.

Noncoding RNAs in tumor metastasis: molecular and clinical perspectives

Metastasis is the main culprit of cancer-associated mortality and involves a complex and multistage process termed the metastatic cascade, which requires tumor cells to detach from the primary site, intravasate, disseminate in the circulation, extravasate, adapt to the foreign microenvironment, and form organ-specific colonization. Each of these processes has been already studied extensively for molecular mechanisms focused mainly on protein-coding genes. Recently, increasing evidence is pointing towards RNAs without coding potential for proteins, referred to as non-coding RNAs, as regulators in shaping cellular activity. Since those first reports, the detection and characterization of non-coding RNA have explosively thrived and greatly enriched the understanding of the molecular regulatory networks in metastasis. Moreover, a comprehensive description of ncRNA dysregulation will provide new insights into novel tools for the early detection and treatment of metastatic cancer. In this review, we focus on discussion of the emerging role of ncRNAs in governing cancer metastasis and describe step by step how ncRNAs impinge on cancer metastasis. In particular, we highlight the diagnostic and therapeutic applications of ncRNAs in metastatic cancer.

microRNA-based diagnostic and therapeutic applications in cancer medicine

It has been almost two decades since the first link between microRNAs and cancer was established. In the ensuing years, this abundant class of short noncoding regulatory RNAs has been studied in virtually all cancer types. This tremendously large body of research has generated innovative technological advances for detection of microRNAs in tissue and bodily fluids, identified the diagnostic, prognostic, and/or predictive value of individual microRNAs or microRNA signatures as potential biomarkers for patient management, shed light on regulatory mechanisms of RNA-RNA interactions that modulate gene expression, uncovered cell-autonomous and cell-to-cell communication roles of specific microRNAs, and developed a battery of viral and nonviral delivery approaches for therapeutic intervention. Despite these intense and prolific research efforts in preclinical and clinical settings, there are a limited number of microRNA-based applications that have been incorporated into clinical practice. We review recent literature and ongoing clinical trials that highlight most promising approaches and standing challenges to translate these findings into viable microRNA-based clinical tools for cancer medicine. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Optimizing Adaptive Therapy Based on the Reachability to Tumor Resistant Subpopulation

Simple Summary

The intra-competition among tumor subpopulations is a promising target to modify and control the outgrowth of the resistant subpopulation. Adaptive therapy lives up to this principle well, but the gain of tumors with an aggressive resistant subpopulation is not superior to maximum tolerated dose therapy (MTD). How to integrate these two therapies to maximize the outcome? According to the model and system reachability, the ‘restore index’ is proposed to evaluate the timing of the transition from the treatment cycle of adaptive therapy to high-frequency administration, and to juggle the benefits of intra-competition and killing of the sensitive subpopulation. Based on the simulation and animal experiment, the effectiveness of this method in treating tumors with an aggressive resistant subpopulation has been confirmed.

Abstract

Adaptive therapy exploits the self-organization of tumor cells to delay the outgrowth of resistant subpopulations successfully. When the tumor has aggressive resistant subpopulations, the outcome of adaptive therapy was not superior to maximum tolerated dose therapy (MTD). To explore methods to improve the adaptive therapy’s performance of this case, the tumor system was constructed by osimertinib-sensitive and resistant cell lines and illustrated by the Lotka-Volterra model in this study. Restore index proposed to assess the system reachability can predict the duration of each treatment cycle. Then the threshold of the restore index was estimated to evaluate the timing of interrupting the treatment cycle and switching to high-frequency administration. The introduced reachability-based adaptive therapy and classic adaptive therapy were compared through simulation and animal experiments. The results suggested that reachability-based adaptive therapy showed advantages when the tumor has an aggressive resistant subpopulation. This study provides a feasible method for evaluating whether to continue the adaptive therapy treatment cycle or switch to high-frequency administration. This method improves the gain of adaptive therapy by taking into account the benefits of tumor intra-competition and the tumor control of killing sensitive subpopulation.

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.

Breast Cancer Drug Resistance: Overcoming the Challenge by Capitalizing on MicroRNA and Tumor Microenvironment Interplay

The clinical management of breast cancer reaches new frontiers every day. However, the number of drug resistant cases is still high, and, currently, this constitutes one of the major challenges that cancer research has to face. For instance, 50% of women affected with HER2 positive breast cancer presents or acquires resistance to trastuzumab. Moreover, for patients affected with triple negative breast cancer, standard chemotherapy is still the fist-line therapy, and often patients become resistant to treatments. Tumor microenvironment plays a crucial role in this context. Indeed, cancer-associated stromal cells deliver oncogenic cues to the tumor and vice versa to escape exogenous insults. It is well known that microRNAs are among the molecules exploited in this aberrant crosstalk. Indeed, microRNAs play a crucial function both in the induction of pro-tumoral traits in stromal cells and in the stroma-mediated fueling of tumor aggressiveness. Here, we summarize the most recent literature regarding the involvement of miRNAs in the crosstalk between tumor and stromal cells and their capability to modulate tumor microenvironment characteristics. All up-to-date findings suggest that microRNAs in the TME could serve both to reverse malignant phenotype of stromal cells, modulating response to therapy, and as predictive/prognostic biomarkers.

Radiolabeling and PET-MRI microdosing of the experimental cancer therapeutic, MN-anti-miR10b, demonstrates delivery to metastatic lesions in a murine model of metastatic breast cancer

BACKGROUND

In our earlier work, we identified microRNA-10b (miR10b) as a master regulator of the viability of metastatic tumor cells. This knowledge allowed us to design a miR10b-targeted therapeutic consisting of anti-miR10b and ultrasmall iron oxide magnetic nanoparticles (MN), termed MN-anti-miR10b. In mouse models of breast cancer, we demonstrated that MN-anti-miR10b caused durable regressions of established metastases with no evidence of systemic toxicity. As a first step towards translating MN-anti-miR10b for the treatment of metastatic breast cancer, we needed to determine if MN-anti-miR10b, which is so effective in mice, will also accumulate in human metastases.

RESULTS

In this study, we devised a method to efficiently radiolabel MN-anti-miR10b with Cu-64 (64Cu) and evaluated the pharmacokinetics and biodistribution of the radiolabeled product at two different doses: a therapeutic dose, referred to as macrodose, corresponding to 64Cu-MN-anti-miR10b co-injected with non-labeled MN-anti-miR10b, and a tracer level dose of 64Cu-MN-anti-miR10b, referred to as microdose. In addition, we evaluated the uptake of 64Cu-MN-anti-miR10b by metastatic lesions using both in vivo and ex vivo positron emission tomography-magnetic resonance imaging (PET-MRI). A comparable distribution of the therapeutic was observed after administration of a microdose or macrodose. Uptake of the therapeutic by metastatic lymph nodes, lungs, and bone was also demonstrated by PET-MRI with a significantly higher PET signal than in the same organs devoid of metastatic lesions.

CONCLUSION

Our results demonstrate that PET-MRI following a microdose injection of the agent will accurately reflect the innate biodistribution of the therapeutic. The tools developed in the present study lay the groundwork for the clinical testing of MN-anti-miR10b and other similar therapeutics in patients with cancer.

CRISPR/Cas13-Based Approaches for Ultrasensitive and Specific Detection of microRNAs

MicroRNAs (miRNAs) have a prominent role in virtually every aspect of cell biology. Due to the small size of mature miRNAs, the high degree of similarity between miRNA family members, and the low abundance of miRNAs in body fluids, miRNA expression profiling is technically challenging. Biosensors based on electrochemical detection for nucleic acids are a novel category of inexpensive and very sensitive diagnostic tools. On the other hand, after recognizing the target sequence, specific CRISPR-associated proteins, including orthologues of Cas12, Cas13, and Cas14, exhibit collateral nonspecific catalytic activities that can be employed for specific and ultrasensitive nucleic acid detection from clinically relevant samples. Recently, several platforms have been developed, connecting the benefits of enzyme-assisted signal amplification and enzyme-free amplification biosensing technologies with CRISPR-based approaches for miRNA detection. Together, they provide high sensitivity, precision, and fewer limitations in diagnosis through efficient sensors at a low cost and a simple miniaturized readout. This review provides an overview of several CRISPR-based biosensing platforms that have been developed and successfully applied for ultrasensitive and specific miRNA detection.

Cancer-associated miRNAs and their therapeutic potential

MicroRNA (miRNA; miR) is a functionally small non-coding RNA and can negatively regulate gene expression by directly binding to the target gene. Some miRNAs are closely involved in the development and progression of cancer and are abnormally expressed in many cancer types. Therefore, control of the expression of cancer-associated miRNAs is expected as a next-generation drug modality to treat advanced types of cancers with high unmet medical needs. Indeed, miRNA therapeutics, which are based on the functional inhibition of oncogenic miRNA (OncomiR) using antisense oligonucleotides (anti-miR) and the replacement via the introduction of a synthetic miRNA mimic for tumor suppressive miRNA (TS-miR), have been developed. In this review, we summarize cancer-associated miRNAs related to various cancer pathologies and their clinical application to miRNA therapeutics for cancer.

MicroRNAs Determining Carcinogenesis by Regulating Oncogenes and Tumor Suppressor Genes During Cell Cycle

AIM

To provide a review considering microRNAs regulating oncogenes and tumor suppressor genes during the different stages of cell cycle, controlling carcinogenesis.

METHODS

The role of microRNAs involved as oncogenes' and tumor suppressor genes' regulators in cancer was searched in the relevant available literature in MEDLINE, including terms such as "microRNA", "oncogenes", "tumor suppressor genes", "metastasis", "cancer" and others.

RESULTS

MicroRNAs determine the expression levels of multiple cell cycle regulators, such as cyclins, cyclin dependent kinases and other major cell cycle activators including retinoblastoma 1 (RB- 1) and p53, resulting in alteration and promotion/inhibition of the cell cycle.

CONCLUSION

MicroRNAs are proven to have a key role in cancer pathophysiology by altering the expression profile of different regulator proteins during cell division cycle and DNA replication. Thus, by acting as oncogenes and tumor suppressor genes, they can either promote or inhibit cancer development and formation, revealing their innovative role as biomarkers and therapeutic tools.

MiRNA10b-directed nanotherapy effectively targets brain metastases from breast cancer

RNA interference represents one of the most appealing therapeutic modalities for cancer because of its potency, versatility, and modularity. Because the mechanism is catalytic and affects the expression of disease-causing antigens at the post-transcriptional level, only small amounts of therapeutic need to be delivered to the target in order to exert a robust therapeutic effect. RNA interference is also advantageous over other treatment modalities, such as monoclonal antibodies or small molecules, because it has a much broader array of druggable targets. Finally, the complementarity of the genetic code gives us the opportunity to design RNAi therapeutics using computational, rational approaches. Previously, we developed and tested an RNAi-targeted therapeutic, termed MN-anti-miR10b, which was designed to inhibit the critical driver of metastasis and metastatic colonization, miRNA-10b. We showed in animal models of metastatic breast cancer that MN-anti-miR10b accumulated into tumors and metastases in the lymph nodes, lungs, and bone, following simple intravenous injection. We also found that treatment incorporating MN-anti-miR10b was effective at inhibiting the emergence of metastases and could regress already established metastases in the lymph nodes, lungs, and bone. In the present study, we extend the application of MN-anti-miR10b to a model of breast cancer metastatic to the brain. We demonstrate delivery to the metastatic lesions and obtain evidence of a therapeutic effect manifested as inhibition of metastatic progression. This investigation represents an additional step towards translating similar RNAi-targeted therapeutics for the systemic treatment of metastatic disease.

Beyond regulations at DNA levels: A review of epigenetic therapeutics targeting cancer stem cells

In the past few years, the paramount role of cancer stem cells (CSCs), in terms of cancer initiation, proliferation, metastasis, invasion and chemoresistance, has been revealed by accumulating studies. However, this level of cellular plasticity cannot be entirely explained by genetic mutations. Research on epigenetic modifications as a complementary explanation for the properties of CSCs has been increasing over the past several years. Notably, therapeutic strategies are currently being developed in an effort to reverse aberrant epigenetic alterations using specific chemical inhibitors. In this review, we summarize the current understanding of CSCs and their role in cancer progression, and provide an overview of epigenetic alterations seen in CSCs. Importantly, we focus on primary cancer therapies that target the epigenetic modification of CSCs by the use of specific chemical inhibitors, such as histone deacetylase (HDAC) inhibitors, DNA methyltransferase (DNMT) inhibitors and microRNA‐based (miRNA‐based) therapeutics.

Recent Progress on Relevant microRNAs in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a neurodevelopmental disorder whose pathogenesis is unclear and is affected by both genetic and environmental factors. The microRNAs (miRNAs) are a kind of single-stranded non-coding RNA with 20-22 nucleotides, which normally inhibit their target mRNAs at a post-transcriptional level. miRNAs are involved in almost all biological processes and are closely related to ASD and many other diseases. In this review, we summarize relevant miRNAs in ASD, and analyze dysregulated miRNAs in brain tissues and body fluids of ASD patients, which may contribute to the pathogenesis and diagnosis of ASD.

Switchable Fluorescence of Doxorubicin for Label-Free Imaging of Bioorthogonal Drug Release

Monitoring the release and activation of prodrug formulations provides essential information about the outcome of a therapy. While the prodrug delivery can be confirmed by using different imaging techniques, confirming the release of active payload by using imaging is a challenge. Here, we have discovered that the switchable fluorescence of doxorubicin can validate drug release upon its uncaging reaction with a highly specific chemical partner. We have observed that the conjugation of doxorubicin with a trans-cyclooctene (TCO) diminishes its fluorescence at 595 nm. This quenched fluorescence of the doxorubicin prodrug is recovered upon its bond-cleaving reaction with tetrazine. Clinically assessed iron oxide nanoparticles were used to formulate a doxorubicin nanodrug. The release of doxorubicin from the nanodrug was studied under various experimental conditions. A fivefold increase in doxorubicin fluorescence is observed after complete release. The studies were carried out in vitro in MDA-MB-231 breast cancer cells. An increase in Dox signal was observed upon tetrazine administration. This switchable fluorescence mechanism of Dox could be employed for fundamental studies, that is, the reactivity of various tetrazine and TCO linker types under different experimental conditions. In addition, the system could be instrumental for translational research where the release and activation of doxorubicin prodrug payloads can be monitored by using optical imaging systems.

miR-216a-targeting theranostic nanoparticles promote proliferation of insulin-secreting cells in type 1 diabetes animal model

Aberrant expression of miRNAs in pancreatic islets is closely related to the development of type 1 diabetes (T1D). The aim of this study was to identify key miRNAs dysregulated in pancreatic islets during T1D progression and to develop a theranostic approach to modify their expression using an MRI-based nanodrug consisting of iron oxide nanoparticles conjugated to miRNA-targeting oligonucleotides in a mouse model of T1D. Isolated pancreatic islets were derived from NOD mice of three distinct age groups (3, 8 and 18-week-old). Total RNA collected from cultured islets was purified and global miRNA profiling was performed with 3D-Gene global miRNA microarray mouse chips encompassing all mouse miRNAs available on the Sanger miRBase V16. Of the miRNAs that were found to be differentially expressed across three age groups, we identified one candidate (miR-216a) implicated in beta cell proliferation for subsequent validation by RT-PCR. Alterations in miR-216a expression within pancreatic beta cells were also examined using in situ hybridization on the frozen pancreatic sections. For in vitro studies, miR-216a mimics/inhibitors were conjugated to iron oxide nanoparticles and incubated with beta cell line, βTC-6. Cell proliferation marker Ki67 was evaluated. Expression of the phosphatase and tensin homolog (PTEN), which is one of the direct targets of miR-216a, was analyzed using western blot. For in vivo study, the miR-216a mimics/inhibitors conjugated to the nanoparticles were injected into 12-week-old female diabetic Balb/c mice via pancreatic duct. The delivery of the nanodrug was monitored by in vivo MRI. Blood glucose of the treated mice was monitored post injection. Ex vivo histological analysis of the pancreatic sections included staining for insulin, PTEN and Ki67. miRNA microarray demonstrated that the expression of miR-216a in the islets from NOD mice significantly changed during T1D progression. In vitro studies showed that treatment with a miR-216a inhibitor nanodrug suppressed proliferation of beta cells and increased the expression of PTEN, a miR-216a target. In contrast, introduction of a mimic nanodrug decreased PTEN expression and increased beta cell proliferation. Animals treated in vivo with a mimic nanodrug had higher insulin-producing functionality compared to controls. These observations were in line with downregulation of PTEN and increase in beta cell proliferation in that group. Our studies demonstrated that miR-216a could serve as a potential therapeutic target for the treatment of diabetes. miR-216a-targeting theranostic nanodrugs served as exploratory tools to define functionality of this miRNA in conjunction with in vivo MR imaging.

The network of non-coding RNAs and their molecular targets in breast cancer

Background

Non-coding RNAs are now recognized as fundamental components of the cellular processes. Non-coding RNAs are composed of different classes, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). Their detailed roles in breast cancer are still under scrutiny.

Main body

We systematically reviewed from recent literature the many functional and physical interactions of non-coding RNAs in breast cancer. We used a data driven approach to establish the network of direct, and indirect, interactions. Human curation was essential to de-convolute and critically assess the experimental approaches in the reviewed articles. To enrol the scientific papers in our article cohort, due to the short time span (shorter than 5 years) we considered the journal impact factor rather than the citation number.

The outcome of our work is the formal establishment of different sub-networks composed by non-coding RNAs and coding genes with validated relations in human breast cancer. This review describes in a concise and unbiased fashion the core of our current knowledge on the role of lncRNAs, miRNAs and other non-coding RNAs in breast cancer.

Conclusions

A number of coding/non-coding gene interactions have been investigated in breast cancer during recent years and their full extent is still being established. Here, we have unveiled some of the most important networks embracing those interactions, and described their involvement in cancer development and in its malignant progression.

MicroRNA-710 regulates multiple pathways of carcinogenesis in murine metastatic breast cancer

Prior research has shown that critical differences between non-metastatic and metastatic tumor cells are at the level of microRNA. Consequently, harnessing these molecules for the treatment of metastatic cancer could have significant clinical impact. In the present study, we set out to identify metastasis-specific microRNAs which drive metastatic colonization of distant organs. Using a murine model of metastatic breast cancer, we employed a directed approach in which we screened for microRNAs that are differentially expressed between the primary tumors and metastatic lesions but concordantly expressed in all of the metastatic lesions irrespective of the tissue that is colonized. Of the identified targets, we focused on miR-710, which was consistently and significantly downregulated in the metastatic lesions relative to the primary tumors. The level of downregulation was independent of the distant organ that is involved, suggesting that miR-710 plays a fundamental role in metastatic colonization. Computational target prediction suggested a pleiotropic role for miR-710 in apoptosis, migration and invasion, and stemness. Using a previously validated oligonucleotide delivery system, we introduced miR-710 mimics into 4T1 metastatic breast adenocarcinoma cells and assessed the resultant phenotypic effects. We demonstrated significant inhibition of cell viability, migration, and invasion. We also showed that the treatment profoundly enhanced cell senescence, reduced stemness, and influenced markers of epithelial to mesenchymal transition, as evidenced by enhanced E-cadherin and reduced vimentin expression. This knowledge represents a first step towards harnessing a similar approach to discover novel microRNA targets with therapeutic potential in metastasis.

Exploring specific prognostic biomarkers in triple-negative breast cancer

Lacking of both prognostic biomarkers and therapeutic targets, triple-negative breast cancer (TNBC) underscores pivotal needs to uncover novel biomarkers and viable therapies. MicroRNAs have broad biological functions in cancers and may serve as ideal biomarkers. In this study, by data mining of the Cancer Genome Atlas database, we screened out 4 differentially-expressed microRNAs (DEmiRNAs) between TNBC and normal samples: miR-135b-5p, miR-9-3p, miR-135b-3p and miR-455-5p. They were specially correlated with the prognosis of TNBC but not non-TNBC. The weighted correlation network analysis (WGCNA) for potential target genes of 3 good prognosis-related DEmiRNAs (miR-135b-5p, miR-9-3p, miR-135b-3p) identified 4 hub genes with highly positive correlation with TNBC subtype: FOXC1, BCL11A, FAM171A1 and RGMA. The targeting relationships between miR-9-3p and FOXC1/FAM171A1, miR-135b-3p and RGMA were validated by dual-luciferase reporter assays. Importantly, the regulatory functions of 4 DEmiRNAs and 3 verified target genes on cell proliferation and migration were explored in TNBC cell lines. In conclusion, we shed lights on these 4 DEmiRNAs (miR-135b-5p, miR-9-3p, miR-135b-3p, miR-455-5p) and 3 hub genes (FOXC1, FAM171A1, RGMA) as specific prognostic biomarkers and promising therapeutic targets for TNBC.

CBFβ/RUNX3-miR10b-TIAM1 molecular axis inhibits proliferation, migration, and invasion of gastric cancer cells

Gastric cancer (GC) is one of the most common malignant tumors of the digestive system. A deeper understanding of the mechanism of proliferation and metastasis is needed to improve patient survival. T cell lymphoma invasion and metastasis 1 (TIAM1) has been proven to play an essential role in the proliferation and metastasis of GC. The aim of this study was to explore the relevant upstream regulatory mechanism of TIAM1. Bioinformatic analysis, RT-qPCR, and dual luciferase reporter assays were used to predict and validate microRNAs that target the TIAM1 gene. Among eleven predicted microRNAs, eight (miR-10b-5p, miR-589-3p, miR-651-3p, miR-335-3p, miR-653-5p, miR-373-3p, miR-372-3p, and miR-205-3p) affected TIAM1 expression; and only miR-10b-5p regulated TIAM1 expression by directly binding to the 3'-UTR of TIAM1 mRNA. miR-10b-5p levels were determined in both normal and cancerous tissues retrieved from GC patients. We observed that by targeting TIAM1 expression, miR-10b-5p inhibited the proliferation, migration, and invasion of GC cells. To verify our observations, we evaluated the participation of runt-related transcription factor 3 (RUNX3), a known regulator of microRNA expression and tumor suppressor. Tumor-suppressor RUNX3 combined with core-binding factor subunit beta (CBFβ) upregulated miR-10b-5p and suppressed GC. In conclusion, we identified a CBFβ/RUNX3-miR10b-TIAM1 molecular axis that inhibits GC progression and metastasis and may provide suitable treatment targets for GC.

MicroRNAs and metastasis: small RNAs play big roles

MicroRNAs (miRNAs) are small non-coding RNAs regulating post-transcriptional gene expression. They play important roles in many biological processes under physiological or pathological conditions, including development, metabolism, tumorigenesis, metastasis, and immune response. Over the past 15 years, significant insights have been gained into the roles of miRNAs in cancer. Depending on the cancer type, miRNAs can act as oncogenes, tumor suppressors, or metastasis regulators. In this review, we focus on the role of miRNAs as components of molecular networks regulating metastasis. These miRNAs, termed metastamiRs, promote or inhibit metastasis through various mechanisms, including regulation of migration, invasion, colonization, cancer stem cell properties, epithelial-mesenchymal transition, and microenvironment. Some of these metastamiRs represent attractive therapeutic targets for cancer treatment.

RNAi-Mediated PD-L1 Inhibition for Pancreatic Cancer Immunotherapy

The recent past has seen impressive progress in the treatment of various malignancies using immunotherapy. One of the most promising approaches involves immune checkpoint inhibitors. However, the clinical results with these agents have demonstrated variability in the response. Pancreatic cancer, in particular, has proven resistant to initial immunotherapy approaches. Here, we describe an alternative strategy that relies on combining gemcitabine and a novel programmed death-ligand 1 (PD-L1) inhibitor, termed MN-siPDL1. MN-siPDL1 incorporates small interfering RNA against PD-L1 (siPDL1) conjugated to a magnetic nanocarrier (MN). We show that noninvasive magnetic resonance imaging (MRI) could be used to monitor therapeutic response. Combination therapy consisting of gemcitabine and MN-siPDL1 in a syngeneic murine pancreatic cancer model resulted in a significant reduction in tumor growth and an increase in survival. Following optimization, a 90% reduction in tumor volume was achieved 2 weeks after the beginning of treatment. Whereas 100% of the control animals had succumbed to their tumors by week 6 after the beginning of treatment, there was no mortality in the experimental group by week 5, and 67% of the experimental animals survived for 12 weeks. This method could provide therapeutic benefit against an intractable disease for which there are no effective treatments and which is characterized by a mere 1% 5-year survival.

Therapeutic microRNAs in human cancer

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

The fundamental role of miR-10b in metastatic cancer

Small, non-coding strands of RNA have been identified as a significant player in the pathology of cancer. One of the first miRNAs to be shown as having aberrant expression in cancer was miR-10b. Since the inaugural study on miR-10b, its role as a metastasis promoting factor has been extensively validated. To date, more than 100 studies have been completed on miR-10b and metastasis across 18 cancer types. This immense set of information holds possibilities for novel methods to improve the lives of many. This review outlines what is currently understood of miR-10b's clinical significance, its molecular regulation, and the possible diagnostic and therapeutic methods leveraging miR-10b as a fundamental target in metastatic cancer. Such methods would move us closer to developing a truly individualized therapeutic strategy against cancer and will likely provide unique information about cancer staging, disease outcome, metastatic potential, and ultimately survival.

OncomiR-10b hijacks the small molecule inhibitor linifanib in human cancers

The pervasive role of microRNAs (miRNAs) in cancer pathobiology drives the introduction of new drug development approaches such as miRNA inhibition. In order to advance miRNA-therapeutics, meticulous screening strategies addressing specific tumor targets are needed. Small molecule inhibitors represent an attractive goal for these strategies. In this study, we devised a strategy to screen for small molecule inhibitors that specifically inhibit, directly or indirectly, miR-10b (SMIRs) which is overexpressed in metastatic tumors. We found that the multi-tyrosine kinase inhibitor linifanib could significantly inhibit miR-10b and reverse its oncogenic function in breast cancer and liver cancer both in vitro and in vivo. In addition, we showed that the efficacy of linifanib to inhibit tyrosine kinases was reduced by high miR-10b levels. When the level of miR-10b is high, it can “hijack” the linifanib and reduce its kinase inhibitory effects in cancer resulting in reduced anti-tumor efficacy. In conclusion, our study describes an effective strategy to screen for small molecule inhibitors of miRNAs. We further propose that miR-10b expression levels, due to the newly described “hijacking” effect, may be used as a biomarker to select patients for linifanib treatment.

Potent and selective effect of the mir-10b inhibitor MN-anti-mir10b in human cancer cells of diverse primary disease origin

Since microRNAs (miRNAs, miRs) have been implicated in oncogenesis, many of them have been identified as therapeutic targets. Previously we have demonstrated that miRNA-10b acts as a master regulator of the viability of metastatic tumor cells and represents a target for therapeutic intervention. We designed and synthesized an inhibitor of miR-10b, termed MN-anti-miR10b. We showed that treatment with MN-anti-miR10b led to durable regression/elimination of established metastases in murine models of metastatic breast cancer. Since miRNA-10b has been associated with various metastatic and non-metastatic cancers, in the present study, we investigated the effect of MN-anti-miR10b in a panel of over 600 cell lines derived from a variety of human malignancies. We observed an effect on the viability of multiple cell lines within each cancer type and a mostly dichotomous response with cell lines either strongly responsive to MN-anti-miR10b or not at all even at maximum dose tested, suggesting a very high specificity of the effect. Genomic modeling of the drug response showed enrichment of genes associated with the proto-oncogene, c-Jun.

New Directions in the Study and Treatment of Metastatic Cancer

Traditional cancer therapy has relied on a strictly cytotoxic approach that views non-metastatic and metastatic tumor cells as identical in terms of molecular biology and sensitivity to therapeutic intervention. Mounting evidence suggests that, in fact, non-metastatic and metastatic tumor cells differ in key characteristics that could explain the capacity of the metastatic cells to not only escape the primary organ but also to survive while in the circulation and to colonize a distant organ. Here, we lay out a framework for a new multi-pronged therapeutic approach. This approach involves modifying the local microenvironment of the primary tumor to inhibit the formation and release of metastatic cells; normalizing the microenvironment of the metastatic organ to limit the capacity of metastatic tumor cells to invade and colonize the organ; remediating the immune response to tumor neoantigens; and targeting metastatic tumor cells on a systemic level by restoring critical and unique aspects of the cell’s phenotype, such as anchorage dependence. Given the limited progress against metastatic cancer using traditional therapeutic strategies, the outlined paradigm could provide a more rational alternative to patients with metastatic cancer.

Inherited Cardiomyopathies and the Role of Mutations in Non-coding Regions of the Genome

Cardiomyopathies (CMs) are a group of cardiac pathologies caused by an intrinsic defect within the myocardium. The relative contribution of genetic mutations in the pathogenesis of certain CMs, such as hypertrophic cardiomyopathy (HCM), arrythmogenic right/left ventricular cardiomyopathy (ARVC) and left ventricular non-compacted cardiomyopathy (LVNC) has been established in comparison to dilated cardiomyopathy (DCM) and restrictive cardiomyopathy (RCM). The aim of this article is to review mutations in the non-coding parts of the genome, namely, microRNA, promoter elements, enhancer/silencer elements, 3′/5′UTRs and introns, that are involved in the pathogenesis CMs. Additionally, we will explore the role of some long non-coding RNAs in the pathogenesis of CMs.

Effect of miR-146a-5p on proliferation and metastasis of triple-negative breast cancer via regulation of SOX5

MicroRNA (miR)-146a-5p functions as a tumor suppressor in various types of cancer. However, the role of miR-146a-5p in the development of triple-negative breast cancer (TNBC) is unclear. The present study aimed to investigate the role of miR-146a-5p in TNBC. The expression level of miR-146a-5p in TNBC tissues and cell lines was initially detected using reverse transcription-quantitative polymerase chain reaction. To predict the target gene of miR-146a-5p, TargetScan software was used and a dual luciferase assay was performed to verify the prediction. Furthermore, in order to explore the role of miR-146a-5p in TNBC, miR-146a-5p was overexpressed in TNBC cells using miR-146a-5p mimics. An MTT assay was performed to detect cell proliferation, and a Transwell assay was conducted to determine cell migration and invasion. Furthermore, western blotting was performed to measure associated protein expression. It was revealed that miR-146a-5p was downregulated in TNBC tissues and cell lines. SOX5 was indicated to be a target gene of miR-146a-5p and was upregulated in TNBC cells. Additionally, miR-146a-5p could inhibit TNBC cell proliferation, migration and invasion, repress the expression of mesenchymal markers (N-cadherin, vimentin and fibronectin) and increase epithelial marker (E-cadherin) expression. Furthermore, SOX5 overexpression eliminated the effects of miR-146a-5p mimics on TNBC cells. In conclusion, the data of the present study indicated that miR-146a-5p inhibits the proliferation and metastasis of TNBC cells by regulating SOX5.

Using Genome Sequence to Enable the Design of Medicines and Chemical Probes

Rapid progress in genome sequencing technology has put us firmly into a postgenomic era. A key challenge in biomedical research is harnessing genome sequence to fulfill the promise of personalized medicine. This Review describes how genome sequencing has enabled the identification of disease-causing biomolecules and how these data have been converted into chemical probes of function, preclinical lead modalities, and ultimately U.S. Food and Drug Administration (FDA)-approved drugs. In particular, we focus on the use of oligonucleotide-based modalities to target disease-causing RNAs; small molecules that target DNA, RNA, or protein; the rational repurposing of known therapeutic modalities; and the advantages of pharmacogenetics. Lastly, we discuss the remaining challenges and opportunities in the direct utilization of genome sequence to enable design of medicines.

Guidelines for Rational Cancer Therapeutics

Traditionally, cancer therapy has relied on surgery, radiation therapy, and chemotherapy. In recent years, these interventions have become increasingly replaced or complemented by more targeted approaches that are informed by a deeper understanding of the underlying biology. Still, the implementation of fully rational patient-specific drug design appears to be years away. Here, we present a vision of rational drug design for cancer that is defined by two major components: modularity and image guidance. We suggest that modularity can be achieved by combining a nanocarrier and an oligonucleotide component into the therapeutic. Image guidance can be incorporated into the nanocarrier component by labeling with a specific imaging reporter, such as a radionuclide or contrast agent for magnetic resonance imaging. While limited by the need for additional technological advancement in the areas of cancer biology, nanotechnology, and imaging, this vision for the future of cancer therapy can be used as a guide to future research endeavors.

Applications of Extracellular RNAs in Oncology

Extracellular RNAs consist of coding and non-coding transcripts released from all cell types, which are involved in multiple cellular processes, predominantly through regulation of gene expression. Recent advances have helped us better understand the functions of these molecules, particularly microRNAs (miRNAs). Numerous pre-clinical and human studies have demonstrated that miRNAs are dysregulated in cancer and contribute to tumorigenesis and metastasis. miRNA profiling has extensively been evaluated as a non-invasive method for cancer diagnosis, prognostication, and assessment of response to cancer therapies. Broader applications for miRNAs in these settings are currently under active development. Investigators have also moved miRNAs into the realm of cancer therapy. miRNA antagonists targeting miRNAs that silence tumor suppressor genes have shown promising pre-clinical activity. Alternatively, miRNA mimics that silence oncogenes are also under active investigation. These miRNA-based cancer therapies are in early development, but represent novel strategies for clinical management of human cancer.

MicroRNA-455-3p promotes invasion and migration in triple negative breast cancer by targeting tumor suppressor EI24

Lacking of treatment methods for the patients with triple negative breast cancer (TNBC) underscores the pivotal needs to further understand its biology as well as to find better biomarkers and develop novel therapeutic strategies. Increasing evidences support that aberrantly expressed microRNAs (miRNAs) are involved in tumorigenesis and may serve as biomarkers for diagnostic and prognostic purposes of various cancers. In current study, we found that miR-455-3p and miR-196a-5p were intensively overexpressed in TNBC compared with the hormone receptor (HR) positive breast cancer whereas miR-425-5p was down-regulated by miRNA microarray analysis. qRT-PCR analysis confirmed that the expression of miR-455-3p in TNBC cell lines MDA-MB-231 and MDA-MB-468 was higher than that in HR positive breast cancer cell line MCF-7(p<0.01). Functional experiments in vitro showed that miR-455-3p enhanced cell proliferative, invasive and migrational abilities in TNBC cell lines. miRNA targets prediction showed SMAD2, LTBR and etoposide induced 2.4 (EI24) were potential target genes of miR-455-3p, and then it was confirmed by qRT-PCR assay. Dual luciferase reporter assay showed the specific binding of miR-455-3p to 3′ UTR of EI24 in TNBC. Then we found miR-455-3p inhibited the EI24 expression at the levels of mRNA and protein. Through small interfering RNA (siRNA) targeting EI24 gene, there were strengthened capabilities of invasion and migration of TNBC cells, and increased expression of EI24 had the inverse effects. In conclusion, the data suggest that miRNA455-3p promotes invasion and migration by targeting tumor suppressor EI24 and might be a potential prognostic biomarker and therapeutic target in TNBC.

Single-trigger dual-responsive nanoparticles for controllable and sequential prodrug activation

Here we have developed a novel approach where two synergistically acting drugs were completely inactivated upon chemical immobilization on a nanoparticle template and activated in response to a chemical stimulus. The activation rate of each drug payload is controlled using a biologically inert bioorthogonal chemistry approach. By exploiting the subtle differences in the 'click-to-release' bioorthogonal reaction, we engineered a single delivery platform capable of releasing the payloads in a time-staggered manner in response to a single dose of a highly specific, yet reactive, small molecule. Incorporation of both di-axial, 'fast release', and di-equatorial, 'slow release', TCO linkers into our nanodrug assembly inhibited the activity of the drug molecules and enabled us to control the timing and activation of each payload. This single-trigger dual-responsive nanoparticle construct and its release kinetics were characterized using two molecular fluorescent probes and tested in vitro for efficient delivery of molecular payloads. In this manuscript we show that this approach was also successful in the treatment of triple negative BT-20 breast cancer cells. Our nanodrug loaded with the slow-releasing doxorubicin and fast-releasing PAC-1 prodrugs displayed a greater therapeutic response than the nanodrug which released both payloads simultaneously.

Therapy targeted to the metastatic niche is effective in a model of stage IV breast cancer

Treatment of stage IV metastatic breast cancer patients is limited to palliative options and represents an unmet clinical need. Here, we demonstrate that pharmacological inhibition of miRNA-10b - a master regulator of metastatic cell viability – leads to elimination of distant metastases in a mouse model of metastatic breast cancer. This was achieved using the miRNA-10b inhibitory nanodrug, MN-anti-miR10b, which consists of magnetic nanoparticles, conjugated to LNA-based miR-10b antagomirs. Intravenous injection of MN-anti-miR10b into mice bearing lung, bone, and brain metastases from breast cancer resulted in selective accumulation of the nanodrug in metastatic tumor cells. Weekly treatments of mice with MN-anti-miR-10b and low-dose doxorubicin resulted in complete regression of pre-existing distant metastases in 65% of the animals and a significant reduction in cancer mortality. These observations were supported by dramatic reduction in proliferation and increase in apoptosis in metastatic sites. On a molecular level, we observed a significant increase in the expression of HOXD10, which is a known target of miRNA-10b. These results represent first steps into the uncharted territory of therapy targeted to the metastatic niche.

MicroRNA therapeutics: towards a new era for the management of cancer and other diseases

In just over two decades since the discovery of the first microRNA (miRNA), the field of miRNA biology has expanded considerably. Insights into the roles of miRNAs in development and disease, particularly in cancer, have made miRNAs attractive tools and targets for novel therapeutic approaches. Functional studies have confirmed that miRNA dysregulation is causal in many cases of cancer, with miRNAs acting as tumour suppressors or oncogenes (oncomiRs), and miRNA mimics and molecules targeted at miRNAs (antimiRs) have shown promise in preclinical development. Several miRNA-targeted therapeutics have reached clinical development, including a mimic of the tumour suppressor miRNA miR-34, which reached phase I clinical trials for treating cancer, and antimiRs targeted at miR-122, which reached phase II trials for treating hepatitis. In this article, we describe recent advances in our understanding of miRNAs in cancer and in other diseases and provide an overview of current miRNA therapeutics in the clinic. We also discuss the challenge of identifying the most efficacious therapeutic candidates and provide a perspective on achieving safe and targeted delivery of miRNA therapeutics.

Ablation of miR-10b Suppresses Oncogene-Induced Mammary Tumorigenesis and Metastasis and Reactivates Tumor-Suppressive Pathways

The invasive and metastatic properties of many human tumors have been associated with upregulation of the miRNA miR-10b, but its functional contributions in this setting have not been fully unraveled. Here, we report the generation of miR-10b-deficient mice, in which miR-10b is shown to be largely dispensable for normal development but critical to tumorigenesis. Loss of miR-10b delays oncogene-induced mammary tumorigenesis and suppresses epithelial-mesenchymal transition, intravasation, and metastasis in a mouse model of metastatic breast cancer. Among the target genes of miR-10b, the tumor suppressor genes Tbx5 and Pten and the metastasis suppressor gene Hoxd10 are significantly upregulated by miR-10b deletion. Mechanistically, miR-10b promotes breast cancer cell proliferation, migration, and invasion through inhibition of the expression of the transcription factor TBX5, leading to repression of the tumor suppressor genes DYRK1A and PTEN In clinical specimens of breast cancer, the expression of TBX5, HOXD10, and DYRK1A correlates with relapse-free survival and overall survival outcomes in patients. Our results establish miR-10b as an oncomiR that drives metastasis, termed a metastamiR, and define the set of critical tumor suppressor mechanisms it overcomes to drive breast cancer progression. Cancer Res; 76(21); 6424-35. ©2016 AACR.

MicroRNA and Metastasis

Noncoding RNAs are important regulatory molecules of cellular processes. MicroRNAs (miRNAs) are small noncoding RNAs that bind to complementary sequences in the 3' untranslated region of target mRNAs, leading to degradation of the target mRNAs and/or inhibition of their translation. Some miRNAs are essential for normal animal development; however, many other miRNAs are dispensable for development but play a critical role in pathological conditions, including tumorigenesis and metastasis. miRNA genes often reside at fragile chromosome sites and are deregulated in cancer. Some miRNAs function as oncogenes or tumor suppressors, collectively termed "oncomirs." Specific metastasis-regulating miRNAs, collectively termed "metastamirs," govern molecular processes and pathways in malignant progression in either a tumor cell-autonomous or a cell-nonautonomous manner. Recently, exosome-transferred miRNAs have emerged as mediators of the tumor-stroma cross talk. In this chapter, we focus on the functions, mechanisms of action, and therapeutic potential of miRNAs, particularly oncomirs and metastamirs.