Publications by authors named "Ka To Shum"

Structured functional RNA entities, including aptamers and siRNAs, have amazing versatility in structure and function. These molecules can serve as powerful, attractive building blocks for the bottom-up assembly of complex nanostructures. Here, we describe novel cell-type specific and internalizing B-cell activating factor receptor (BAFF-R) aptamer-siRNA delivery systems for B-cell lymphoma therapy, in which both the aptamer and the Dicer substrate siRNA (DsiRNA) portions are conjugated through a "sticky bridge.

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Gene therapy carries the promise of cures for many diseases based on manipulating the expression of a person's genes toward the therapeutic goal. The relevance of noncoding oligonucleotides to human disease is attracting widespread attention. Noncoding oligonucleotides are not only involved in gene regulation, but can also be modified into therapeutic tools.

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Lymphomas are cancers that arise from white blood cells and usually present as solid tumors. Treatment of lymphoma often involves chemotherapy, and can also include radiotherapy and/or bone marrow transplantation. There is an un-questioned need for more effective therapies and diagnostic tool for lymphoma.

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Spinal muscular atrophy (SMA) is a severe autosomal recessive disease caused by a genetic defect in the survival motor neuron 1 (SMN1) gene, which encodes SMN, a protein widely expressed in all eukaryotic cells. Depletion of the SMN protein causes muscle weakness and progressive loss of movement in SMA patients. The field of gene therapy has made major advances over the past decade, and gene delivery to the central nervous system (CNS) by in vivo or ex vivo techniques is a rapidly emerging field in neuroscience.

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Viruses replicate inside the cells of an organism and continuously evolve to contend with an ever-changing environment. Many life-threatening diseases, such as AIDS, SARS, hepatitis and some cancers, are caused by viruses. Because viruses have small genome sizes and high mutability, there is currently a lack of and an urgent need for effective treatment for many viral pathogens.

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RNA interference (RNAi) is an evolutionarily conserved, endogenous process for post-transcriptional regulation of gene expression. Although RNAi therapeutics have recently progressed through the pipeline toward clinical trials, the application of these as ideal, clinical therapeutics requires the development of safe and effective delivery systems. Inspired by the immense progress with nanotechnology in drug delivery, efforts have been dedicated to the development of nanoparticle-based RNAi delivery systems.

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Inorganic polyphosphate (polyP) plays a number of critical roles in bacterial persistence, stress, and virulence. PolyP intracellular metabolism is regulated by the polyphosphate kinase (PPK) protein families, and inhibition of PPK activity is a potential approach to disrupting polyP-dependent processes in pathogenic organisms. Here, we biochemically characterized Mycobacterium tuberculosis (MTB) PPK2 and developed DNA-based aptamers that inhibit the enzyme's catalytic activities.

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Sclerostin is an extracellular negative regulator of bone formation that is a recognized therapeutic target for osteoporosis therapy. In the present study, we performed DNA aptamer selection against sclerostin, then characterized aptamer-sclerostin binding and the ability to inhibit sclerostin function in cell culture. We show that a selected DNA aptamer was highly selective for binding to sclerostin with affinities in the nanomolar range as determined by solid-phase assays and by isothermal titration calorimetry.

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The helicase from severe acute respiratory syndrome coronavirus (SARS-CoV) possesses NTPase, duplex RNA/DNA-unwinding and RNA-capping activities that are essential for viral replication and proliferation. Here, we have isolated DNA aptamers against the SARS-CoV helicase from a combinatorial DNA library. These aptamers show two distinct classes of secondary structure, G-quadruplex and non-G-quadruplex, as shown by circular dichroism and gel electrophoresis.

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