Telomere maintenance and telomerase reactivation is essential for the transformation of most human cancer cells. Telomere shortening to the threshold length, mutations of the telomere-associated proteins, and/or telomerase RNA lead to telomeric dysfunction and therefore genomic instability. Telomerase up-regulation in 85% of human cancer cells has become a hallmark of cancers, hence a promising target for anticancer therapy. In this review, we discuss the mechanism of cancer due to telomere dysfunction and the resulting biological effects, the control of telomerase activity, and the new developments in cancer therapies targeting telomere and telomerase.

Fluorinated polymers or chemicals with long length of fluorinated tail are often used to enhance the hydrophobicity and oleophobicity of surfaces. In this work, superhydrophobic and highly solvent-repellent surfaces were fabricated by using a series of block copolymers with 3,3,3-trifluoropropyl substituted siloxane segments via an electrospinning process. The contact angles of deionized water on the electrospun films are higher than 150°and the water roll-off angles are less than 10°, denoting a superhydrophobic property for the electrospun films. The electrospun films can also exhibit contact angles higher than 150°for glycerol, formamide, and diethylene glycol. Moreover, it is surprising to find that very high contact angles with small roll-off angles on the electrospun films could be obtained by using the oil liquids colored by 0.4 wt % oil-soluble dyes. By investigating the properties of the thin/electrospun films of block copolymers, it is found that the microphase-separation behavior of block copolymers could be an important reason for the formation of nanoscale surface roughness. The electrospun films can exhibit superhydrophobicity and high solvent resistance, owing to the formation of multiscale surface roughness as well as the surface segregation of low surface energy groups.

G-Quadruplexes are four-stranded DNA structures that play important regulatory roles in the maintenance of telomere length by inhibiting telomerase activity. Telomeres are specialized functional DNA-protein structures consisting of a variable number of tandem G-rich repeats together with a group of specific proteins. Telomere losses during cell replication are compensated by telomerase, which adds telomeric repeats onto the chromosome ends in the presence of its substrate--the 3'-overhang. Recently, quadruplexes have been considered as a potential therapeutic target for human cancer because they can inhibit telomerase activity, and some quadruplex-interacting drugs can induce senescence and apoptosis of cancer cells. In addition, due to the potassium preference to the other cations, especially sodium ions, quadruplexes have been suggested for developing potassium detection probes with higher sensitivity and selectivity. This review will illustrate these two aspects to provide further understanding of G-quadruplex structures.

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