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

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.

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.

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.

Screening of potential miRNA therapeutics for the prevention of multi-drug resistance in cancer cells.

Chemotherapy, a major cancer treatment approach, suffers seriously from multidrug resistance (MDR), generally caused by innate DNA repair proteins that reverse the DNA modification by anti-cancer therapeutics or trans-membrane efflux proteins that pump anti-cancer therapeutics out of the cytosol. This project focused on finding microRNAs that can regulate MDR proteins by managing corresponding mRNA levels through post-transcriptional regulation based on nucleotide sequence matching. Screening was done with bioinformatics databases for unpublished/unexplored microRNAs with high nucleotide sequence correspondence to two representative MDR proteins, MGMT (a DNA repair protein) and ABCB1 (an efflux protein), revealing microRNA-4539 and microRNA-4261 respectively.

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.

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.

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.

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.

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.

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.

Magnetic resonance imaging of intra-pancreatic ductal nanoparticle delivery to islet cells.

Background: The absence of reliable drug delivery systems to pancreatic islet cells hampers efficient treatment of type 1 diabetes. Nanoparticle delivery systems equipped with imaging capabilities could enable selective delivery to pancreatic islet cells. Biodistribution of nanoparticles is defined by several factors including the mode of administration, which determines accumulation in various organs.

Predictive imaging of chemotherapeutic response in a transgenic mouse model of pancreatic cancer.

The underglycosylated mucin 1 tumor antigen (uMUC1) is a biomarker that forecasts the progression of adenocarcinomas. In this study, we evaluated the utility of a dual-modality molecular imaging approach based on targeting uMUC1 for monitoring chemotherapeutic response in a transgenic murine model of pancreatic cancer (KCM triple transgenic mice). An uMUC1-specific contrast agent (MN-EPPT) was synthesized for use with magnetic resonance imaging (MRI) and fluorescence optical imaging.

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

The therapeutic promise of microRNA (miRNA) in cancer has yet to be realized. In this study, we identified and therapeutically exploited a new role for miR-10b at the metastatic site, which links its overexpression to tumor cell viability and proliferation. In the protocol developed, we combined a miR-10b-inhibitory nanodrug with low-dose anthracycline to achieve complete durable regressions of metastatic disease in a murine model of metastatic breast cancer.

In Vivo Detection of miRNA Expression in Tumors Using an Activatable Nanosensor.

Purpose: The development of tools for the analysis of microRNA (miRNA) function in tumors can advance our diagnostic and prognostic capabilities. Here, we describe the development of technology for the profiling of miRNA expression in the tumors of live animals.

Procedures: The approach is based on miRNA nanosensors consisting of sensor oligonucleotides conjugated to magnetic nanoparticles for systemic delivery.

Detecting enzyme activities with exogenous MRI contrast agents.

This review focuses on exogenous magnetic resonance imaging (MRI) contrast agents that are responsive to enzyme activity. Enzymes can catalyze a change in water access, rotational tumbling time, the proximity of a (19)F-labeled ligand, the aggregation state, the proton chemical-exchange rate between the agent and water, or the chemical shift of (19)F, (31)P, (13)C or a labile (1)H of an agent, all of which can be used to detect enzyme activity. The variety of agents attests to the creativity in developing enzyme-responsive MRI contrast agents.

Design of nanodrugs for miRNA targeting in tumor cells.

The delivery of oligonucleotide antagonists to cytosolic RNA targets such as microRNA represents an avenue for the post-transcriptional control of cellular phenotype. In tumor cells, oncogenic miRNAs, termed oncomirs, are tightly linked to processes that ultimately determine cancer initiation, progression, and response to therapy. Therefore, the capacity to redirect tumor cell fate towards therapeutically beneficial phenotypes holds promise in a future clinical scenario.

Combination treatment with theranostic nanoparticles for glioblastoma sensitization to TMZ.

Purpose: Tumor resistance to chemotherapeutic drugs is one of the major obstacles in the treatment of glioblastoma multiforme (GBM). In this study, we attempted to modulate tumor response to chemotherapy by combination treatment that included experimental (small interference RNA (siRNA), chlorotoxin) and conventional (temozolomide, TMZ) therapeutics.

Procedures: siRNA therapy was used to silence O(6)-methylguanine methyltransferase (MGMT), a key factor in brain tumor resistance to TMZ.

GLP-1R-targeting magnetic nanoparticles for pancreatic islet imaging.

Noninvasive assessment of pancreatic β-cell mass would tremendously aid in managing type 1 diabetes (T1D). Toward this goal, we synthesized an exendin-4 conjugated magnetic iron oxide-based nanoparticle probe targeting glucagon-like peptide 1 receptor (GLP-1R), which is highly expressed on the surface of pancreatic β-cells. In vitro studies in βTC-6, the β-cell line, showed specific accumulation of the targeted probe (termed MN-Ex10-Cy5.

Detection of miRNA expression in intact cells using activatable sensor oligonucleotides.

We describe a technology for the profiling of miRNA expression in intact cells. The technology is based on sensor oligonucleotides that are cleavable, completely complementary to a target miRNA, and dual-labeled with a fluorescent dye and a quencher. Upon entering the cell, the sensor oligonucleotide binds its specific miRNA target through complementary base-pairing.

Detection of in vivo enzyme activity with CatalyCEST MRI.

Purpose: CatalyCEST MRI compares the detection of an enzyme-responsive chemical exchange saturation transfer (CEST) agent with the detection of an unresponsive "control" CEST agent that accounts for other conditions that influence CEST. The purpose of this study was to investigate the feasibility of in vivo catalyCEST MRI.

Methods: CEST agents that were responsive and unresponsive to the activity of urokinase plasminogen activator were shown to have negligible interaction with each other.

Targeted imaging of breast tumor progression and therapeutic response in a human uMUC-1 expressing transgenic mouse model.

The ability to monitor breast cancer initiation and progression on the molecular level would provide an effective tool for early diagnosis and therapy. In the present study, we focused on the underglycosylated MUC-1 tumor antigen (uMUC-1), which is directly linked to tumor progression from pre-malignancy to advanced malignancy in breast cancer and has been identified as the independent predictor of local recurrence and tumor response to chemotherapy. We investigated whether changes in uMUC-1 expression during tumor development and therapeutic intervention could be monitored non-invasively using molecular imaging approach with the uMUC-1-specific contrast agent (MN-EPPT) detectable by magnetic resonance and fluorescence optical imaging.

Fluorescent and lanthanide labeling for ligand screens, assays, and imaging.

The use of fluorescent (or luminescent) and metal contrast agents in high-throughput screens, in vitro assays, and molecular imaging procedures has rapidly expanded in recent years. Here we describe the development and utility of high-affinity ligands for cancer theranostics and other in vitro screening -studies. In this context, we also illustrate the syntheses and use of heteromultivalent ligands as targeted imaging agents.

An amine-derivatized, DOTA-loaded polymeric support for Fmoc Solid Phase Peptide Synthesis.

An amine-derivatized DOTA has been used to modify the surface of a polymeric support for conventional Solid Phase Peptide Synthesis (SPPS) following standard Fmoc chemistry methods. This methodology was used to synthesize a peptide-DOTA conjugate that was demonstrated to be a PARACEST MRI contrast agent. Therefore, this synthesis methodology can facilitate Fmoc SPPS of molecular imaging contrast agents.