Cancer is characterized by uncontrolled cell growth, invasion, and metastasis and possess threat to humans worldwide. The scientific community is facing numerous challenges despite several efforts to cure cancer. Though a number of studies were done earlier, the molecular mechanism of cancer progression is not completely understood. Currently available treatments like surgery resection, adjuvant chemotherapy, and radiotherapy are not completely effective in curing all the cancers. Recent advances in the antisense technology provide a powerful tool to investigate various cancer pathways and target them. Small interfering RNAs (siRNAs) could be effective in downregulating the cancer-associated genes, but their in vivo delivery is the main obstacle. DNA enzymes (DNAzymes) have great potential in the treatment of cancer due to high selectivity and significant catalytic efficiency. In this review, we are focusing on antisense molecules such as siRNA and DNAzymes in cancer therapeutics development. This review also describes the challenges and approaches to overcome obstacles involved in using siRNA and DNAzymes in the treatment of cancers.

The photoisomerization properties of a series of cyclic azobenzene (cAb) analogs, including non-substituted, Br-, CN-, carboxyl-, and amino cAb, were compared. While the transform of these analogs show different degrees of thermal stability, no spectral changes in the absorption wavelengths were observed for amino cAb upon exposure to purple light. The 15 N NMR chemical shifts of cAb in both cis-and trans-forms were found to show a large difference from those of aromatic azobenzene; however, the trend of difference in chemical shift is in agreement with that obtained from quantum chemical calculations. More importantly, the structure of the photoisomerization product from cis-cAb was confirmed to be, indeed, the trans-cAb by X-ray diffraction experiments. The 15 NMR data of the cAb isomers and confirmation of trans-cAb through crystal structure will be of importance for future studies in the design and applications of cAb as a photoswitch.In recent years, spatiotemporal control has been recognized as a useful approach in modulating the structures and functions of biological systems due to the possibility of introducing two regulatory domains, time and location. [1][2][3] While cyclic azobenzene (cAb, 2) was first synthesized in 1910, [4] it only attracted interest very recently with the demonstration of a color change upon exposure to purple light. [5] Compared with the linear aromatic azobenzene (Ab) system 1 (Figure 1), which has found utilities in regulating the structures and functions of peptides, proteins and nucleic acids, [1,[6][7][8][9][10][11] cAb is unique in that the yellow-red isomerization is driven by visible light, and the thermodynamically stable form is the non-planar cis-, as opposed to the co-planar trans-form in Ab, potentially offering spatiotemporal regulation complementary to that of Ab.It was recently reported by us [12] that cAb and analogs can be synthesized from 2,2'-dinitrodibenzyl 3, and transformed into the corresponding D-threoninol conjugate phosphoramidite 4 (Scheme 1) for incorporation into oligonucleotides through solid phase synthesis. We further demonstrated that photoisomerization of cAb can indeed be used to regulate DNA hybridization. [13] While work is currently in progress in our lab to demonstrate the ability of cAb to regulate processes such as DNA transcription and aptamer binding, an understanding of the influence of functional groups of cAb on its photoisomerization properties is necessary in order to design a cAb system for its desired application. More importantly, while it has been assumed in the literature that cis-cAb is transformed into the red trans-cAb upon exposure to purple light, [5] no experimental evidence has been provided to confirm the structure of the photoisomerization product. We report herein the photoisomerization and thermostability of a series of cAb analogs, and the confirmation of the trans-cAb structure by Xray crystallography.The photoisomerization properties of a few cAb analogs, non-substituted, Br-, CN-, carboxyl-and amino-cAb, were inv...

This review summarises the literature on the synthesis and applications of fluorescently labelled carbohydrates. Due to the sensitivity of fluorescent detection, this approach provides a useful tool to study processes involving glycans. A few general categories of labelling are presented, in situ labelling of carbohydrates with fluorophores, fluorescently labelled glycolipids, fluorogenic glycans, pre-formed fluorescent glycans for intracellular applications, glycan-decorated fluorescent polymers, fluorescent glyconanoparticles, and other functional fluorescent glycans.

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4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) and corresponding 4,4-dimethyl and 4,4-diphenyl analogues were treated with cupric nitrate trihydrate under different conditions. Corresponding 3-nitro-, nitromethyl-, hydroxymethyl BODIPY, and BODIPY 3-carboxyaldehyde were obtained. The UV/vis and fluorescent properties of these BODIPY analogues were determined.