PLENARY LECTURE Ⅰ
Chemical Biology of Nucleic Acids: DNA Origami and Artificial Genetic Switches
Prof. Hiroshi Sugiyama
Kyoto University, Japan
The DNA origami method developed for the preparation of fully addressable two-dimensional (2-D) structures has been utilized for the selective positioning of functional molecules and nanoparticles. We designed a DNA frame using the DNA origami method to investigate enzymatic action and DNA structural change. The substrate dsDNAs were incorporated into the cavity of the DNA frame to allow observation of the behaviors and/or reactions of transcription factors, DNA methyltransferase, DNA recombinase, CRISPR-Cas9, MOC1, and DNA repair enzymes. The proteins that bound to the target dsDNA in aqueous solution on a mica surface were visualized using a high-speed atomic force microscope (hs-AFM). We recently developed DNA nanocages using the DNA origami method and investigated the effect of confined space on the properties of G-quadruplex and i-motif, finding that the mechanical and thermodynamic stabilities of the G-quadruplex inside the nanocage were significantly increased. We also developed a strategy for lipid bilayer-assisted self-assembly of various DNA origami tiles into 2-D lattices. Our results clearly demonstrated that the DNA origami method could provide a unique platform for the analysis of biomolecules at the single-molecule level.
Our group has also undertaken original research on the molecular recognition of DNA by antitumor antibiotics, and analyzed atom-specific chemical reactions on DNA. By integrating this information, we synthesized various functionalized sequence-specific DNA-binding pyrrole–imidazole polyamides (PIPs), which act as artificial genetic switches that can switch gene expression on and off on demand. We recently developed an alkylating PIP that could switch off the cancer-related KRAS gene and RUNX 1–3 regulatory genes.[8,9] To switch on gene expression we needed to consider epigenetic factors. We also developed a SAHA–PIP complex that comprised a sequence-specific PIP and HDAC-inhibiting SAHA. Evaluation of the effect of SAHA–PIPs on genome-wide gene expression in human dermal fibroblasts demonstrated that each SAHA–PIP could differentially activate therapeutically important genes. Conjugation of the DNA-binding domain "I" with HAT-activating CTB markedly activated the same cluster of genes as SAHA–PIP "I," substantiating the role of PIP in sequence-specific gene regulation. Recently we introduced a bromodomain inhibitor to PIP to activate gene expression in a sequence-specific manner. To extend the recognition sequence, we introduced a host–guest system to facilitate cooperative binding to the target sequence. We can also control the forward/reverse orientation preference of PIP using a cyclic PIP with a chiral amino group.
In this talk, I will discuss recent progress in molecular analysis using the DNA origami method and regulation of gene expression using specifically designed PIPs.
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DNA nanotechnology; DNA origami; hs-AFM; PIP; genetic switch; epigenetic
PLENARY LECTURE II
A Regulatory Science Approach to Assess the Safety of Medical Devices Incorporating Nanotechnology
Dr. Peter L. Goering
Silver Spring, Maryland, USA
Nanotechnology is significantly impacting the design, development, and manufacture of next-generation medical devices, contributing to advances in disease diagnosis and treatment. Materials engineered at the nanoscale offer size-attributable characteristics, such as large surface area, enhanced optical and electrical properties, anti-microbial activity, and enhanced tissue integration, making them attractive candidates for use in the medical device industry. Nanomaterials have been incorporated into a variety of medical devices, including implantable devices (e.g., orthopedic and dental implants, stents), skin-contacting devices (e.g., wound dressings), and in vitro diagnostic devices. In parallel with the remarkable advances in the use of nanomaterials in medicine, research programs in industry, government agencies, and universities around the world are evaluating the safety of nanomaterials. A robust regulatory science research program to develop the safety profiles of medical devices incorporating nanotechnology includes physical-chemical characterization, in vitro/in vivo models for biological evaluations, and risk assessment. The research goals are to develop and advance the methods, tools, and approaches that will improve safety evaluations of medical devices that incorporate nanotechnology. Projects include safety assessment of discrete nanoparticles and immobilized surface nanostructures used in medical devices with the aim to improve physical-chemical characterization, optimize biological test methods (e.g., genotoxicity), and develop toxicological risk assessment approaches for nanomaterials.
PLENARY LECTURE Ⅲ
Cancer immunotherapy & IL-7: the past, present & future
Prof. Young Chul Sung
Department of Life Science, POSTECH, Pohang, Korea
Genexine, Korea Bio-park, building B-410,
Seongnam-si, Gyeonggi-do, Korea
Cancer immunotherapy began with application of cytokines ( IFN-α & IL-2 ) for treating cancers by boosting host immune system nonspecifically in 1980s. followed by commercialization of mAbs in 1997 (Rituxan for follicular lymphoma).
It is recently highlighted by introduction of immune checkpoint (IC) inhibitors such as anti-PD1, anti-PDL1, and anti-CTLA4.
However to our disappointment, most lymphopenic cancer patients with cold tumors such as pancreatic & colorectal tumors do not have any response to anti-PD1 treatment.
Even in cancer patients with hot tumors, a portion of patients showed durable response to anti-PD1, ranging from 35 to 45%.
So, there is a growing consensus that there are large rooms for IC inhibitor treatments to be improved and the number of T cells in blood & tumor can be a biomarker for predicting the response to anti-PD1 drug.
Here, I will present Hyleukin-7, long-acting IL-7 as a potential lymphopenia drug, which appears to have a strong capability for increasing CD4 & CD8 T cells, but not Tregs, in a dose-dependent manner. In addition, co-treatment of hyleukin-7 significantly enhanced anti-tumor effect of IC inhibitors, indicating a great synergy.
Immunotherapy, Hyleukin-7, Lymphopenia IC inhibitors, synergy