Selective nuclear localization of siRNA by metallic versus semiconducting single wall carbon nanotubes in keratinocytes.

Background: The potential use of carbon nanotubes (CNTs) in gene therapy as delivery systems for nucleic acids has been recently recognized. Here, we describe that metallic versus semiconducting single-wall CNTs can produce significant differences in transfection rate and cellular distribution of siRNA in murine PAM212 keratinocytes.

Results/methodology: The results of cell interaction studies, coupled with supportive computational simulations and ultrastructural studies revealed that the use of metallic single wall CNTs resulted in siRNA delivery into both the cytoplasm and nucleus of keratinocytes, whereas semiconducting CNTs resulted in delivery only to the cytoplasm.

Computational design and biological testing of highly cytotoxic colchicine ring A modifications.

Microtubules are the primary target for many anti-cancer drugs, the majority of which bind specifically to beta-tubulin. The existence of several beta-tubulin isotypes, coupled with their varied expression in normal and cancerous cells provides a platform upon which to construct selective chemotherapeutic agents. We have examined five prevalent human beta-tubulin isotypes and identified the colchicine-binding site as the most promising for drug design based on specificity.

Electrostatic contributions to colchicine binding within tubulin isotypes.

Tubulin, the structural subunit of microtubules, is the target of some highly successful anti-tumor drugs. Most of these drugs bind to the beta-tubulin resulting in the inhibition of microtubule dynamics and eventually cell death. The varied cellular distribution of several human isotypes of beta -tubulin provides a platform upon which to construct novel chemotherapeutic agents that are able to differentiate between these types of cells.