Tyrosine phosphorylation of CARM1 promotes its enzymatic activity and alters its target specificity.

An important epigenetic component of tyrosine kinase signaling is the phosphorylation of histones, and epigenetic readers, writers, and erasers. Phosphorylation of protein arginine methyltransferases (PRMTs), have been shown to enhance and impair their enzymatic activity. In this study, we show that the hyperactivation of Janus kinase 2 (JAK2) by the V617F mutation phosphorylates tyrosine residues (Y149 and Y334) in coactivator-associated arginine methyltransferase 1 (CARM1), an important target in hematologic malignancies, increasing its methyltransferase activity and altering its target specificity. While non-phosphorylatable CARM1 methylates some established substrates (e.g. BAF155 and PABP1), only phospho-CARM1 methylates the RUNX1 transcription factor, on R223 and R319. Furthermore, cells expressing non-phosphorylatable CARM1 have impaired cell-cycle progression and increased apoptosis, compared to cells expressing phosphorylatable, wild-type CARM1, with reduced expression of genes associated with G2/M cell cycle progression and anti-apoptosis. The presence of the JAK2-V617F mutant kinase renders acute myeloid leukemia (AML) cells less sensitive to CARM1 inhibition, and we show that the dual targeting of JAK2 and CARM1 is more effective than monotherapy in AML cells expressing phospho-CARM1. Thus, the phosphorylation of CARM1 by hyperactivated JAK2 regulates its methyltransferase activity, helps select its substrates, and is required for the maximal proliferation of malignant myeloid cells.

Identification of DOT1L inhibitors by structure-based virtual screening adapted from a nucleoside-focused library.

Disruptor of Telomeric Silencing 1-Like (DOT1L), the sole histone H3 lysine 79 (H3K79) methyltransferase, is required for leukemogenic transformation in a subset of leukemias bearing chromosomal translocations of the Mixed Lineage Leukemia (MLL) gene, as well as other cancers. Thus, DOT1L is an attractive therapeutic target and discovery of small molecule inhibitors remain of high interest. Herein, we are presenting screening results for a unique focused library of 1200 nucleoside analogs originally produced under the aegis of the NIH Pilot Scale Library Program. The complete nucleoside set was screened virtually against DOT1L, resulting in 210 putative hits. In vitro screening of the virtual hits resulted in validation of 11 compounds as DOT1L inhibitors clustered into two distinct chemical classes, adenosine-based inhibitors and a new chemotype that lacks adenosine. Based on the developed DOT1L ligand binding model, a structure-based design strategy was applied and a second-generation of non-nucleoside DOT1L inhibitors was developed. Newly synthesized compound 25 was the most potent DOT1L inhibitor in the new series with an IC50 of 1.0 µM, showing 40-fold improvement in comparison with hit 9 and exhibiting reasonable on target effects in a DOT1L dependent murine cell line. These compounds represent novel chemical probes with a unique non-nucleoside scaffold that bind and compete with the SAM binding site of DOT1L, thus providing foundation for further medicinal chemistry efforts to develop more potent compounds.

Nanoparticle systems for cancer vaccine.

As effective tools for public health, vaccines prevent disease by priming the body's adaptive and innate immune responses against an infection. Due to advances in understanding cancers and their relationship with the immune system, there is a growing interest in priming host immune defenses for a targeted and complete antitumor response. Nanoparticle systems have shown to be promising tools for effective antigen delivery as vaccines and/or for potentiating immune response as adjuvants. Here, we highlight relevant physiological processes involved in vaccine delivery, review recent advances in the use of nanoparticle systems for vaccines and discuss pertinent challenges to viably translate nanoparticle-based vaccines and adjuvants for public use.

Polymer-Based Drug Delivery Systems for Cancer.

The standard treatment for metastatic cancer is generally a combination of chemotherapy, surgery, and radiotherapy. Since there are few specific chemotherapeutics approved by the US Food and Drug Administration, systemic chemotherapy is widely employed in the hopes of destroying rapidly dividing cancer cells before doing irreversible damage to the human body. Because of the nature of traditional chemotherapeutics, systemic treatment is associated with various side effects, such as nausea, dysphoria, vomiting, and pain, and long-term, irreversible damage to major organs, such as the kidney and heart. As life expectancy increases, so has the need for reliable cancer therapy that spares or prevents damage to functional healthy organs. One method is to precisely deliver drugs into specific tumor cells and tissues. Polymers have been characterized as favorable systems to deliver drugs with tunable pharmacokinetics, circulation times, biocompatibility, and biodegradability. Here, various types of polymers, modified as drug delivery systems for targeting cancer, and targeting behaviors of polymer-based carriers will be discussed.

Role of microRNA-410 in molecular oncology: A double edged sword.

MicroRNAs (miRNAs) are short non-coding single-stranded RNAs, which play significant roles in the regulation of a myriad of biological processes. Overwhelmingly increasing high-impact research has also deepened our understanding about the central role of miRNAs in cancer development, metastatic spread, and development of resistance against various drugs. Recent studies have identified miRNAs that regulate RNA expression/processing and posttranscriptional expression of important oncogenes and tumor suppressors. Rapidly emerging experimentally verified data have started to shed light on the significance of miRNAs as biomarkers for diagnostic, prognostic, and monitoring purposes. Next-generation sequencing and DNA microarray technologies have helped us tremendously in the identification of miRNA and mRNA signatures in different cancers and their subtypes on a genome-wide scale. It is being increasing realized that miRNAs have diametrically opposite roles in different cancers. miR-410 is context-dependently involved in positive and negative regulation of cancers. miR-410 negatively regulates BAK1, CETN3, and BRD7 to promote cancer. However, miR-410 effectively targetes c-MET, AGTR1, and SNAIL to suppress cancer. In this review, we will comprehensively summarize most recent evidence available related to the "split personality" of miR-410 in different cancers.

Mitochondrion: A Promising Target for Nanoparticle-Based Vaccine Delivery Systems.

Vaccination is one of the most popular technologies in disease prevention and eradication. It is promising to improve immunization efficiency by using vectors and/or adjuvant delivery systems. Nanoparticle (NP)-based delivery systems have attracted increasing interest due to enhancement of antigen uptake via prevention of vaccine degradation in the biological environment and the intrinsic immune-stimulatory properties of the materials. Mitochondria play paramount roles in cell life and death and are promising targets for vaccine delivery systems to effectively induce immune responses. In this review, we focus on NPs-based delivery systems with surfaces that can be manipulated by using mitochondria targeting moieties for intervention in health and disease.