Cell nucleus, targeting

Biju, V, Muraleedharan, D., Nakayama, K, Shinohara, Y., Itoh, T., Baba, Y. and Ishikawa, M. (2007) Quantum dot-insect neuropeptide conjugates for fluorescence imaging, transfection, and nucleus targeting of living cells. Langmuir, 23, 10254-10261. 

Specific Energy—The actual energy per unit mass deposited per unit volume in a small target, such as the cell or cell nucleus, as the result of one or more energy-depositing events. This is a stochastic quantity as opposed to the average value over a large number of instance (i.e., the absorbed dose). 

Radiotherapy generally involves cell destruction, requiring some form of particle emission on decay and a half-life between 1 and 10 days. The choice of a particular therapeutic application determines the type of particle emission (a, ft, or Auger e ), and the energy and half-life of the radionuclide to be used. Considerations include time for delivery of the radiopharmaceutical to its in vivo target, location of the target (tumor surface, tumor cell cytoplasm, tumor cell nucleus) and size of the tumor. The reader is directed to a number of reviews on this subject.15-22... 

Depending on the type of hormone, hormone signals are transmitted to the target cells in different ways. Apolar (lipophilic) hormones penetrate the cell and act in the cell nucleus, while polar (hydrophilic) hormones act on the external cell membrane. 

The cell nucleus is another important source of druggable targets. Surprisingly, the nucleus is not as important to the survival of an individual cell as are many of the cytoplasmic organelles. A cell can live without its nucleus, it just cannot reproduce. (Mature adult human red blood cells, for example, do not have nuclei.) On the other hand, a cell cannot live without its mitochondria. Therefore, the cell nucleus is an important structure to target when designing drugs for diseases in which one wishes to stop cellular reproduction (e.g., cancer, viral or bacterial infections). 

This chapter discusses potential drug targets in each of the main components of cellular stmcture, starting with the cell membrane and working inwards to the cell nucleus. 

This principle has been extended to DNA-protein complexes or genes which can be entrapped and delivered to target cells, the major advantage of the systems being that they tend to be able to penetrate the cell walls, thereby enabling external materials such as genes to penetrate to the cell nucleus. 

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