the drug and other substances can enter cell through specific receptors localized in the surface of cell on plasma membrane by a way which may be complicated dependent the nature of substance, and type of receptor and the mechanism by which the activation of receptor produce a second molecule inside the cell called second messenger. second messenger can then activate a cascade of reaction in the cytoplasm or go to the nucleus to activate a gene or suppress one responsible for cell response.

Please see following article to get your answers

https://www.nature.com/articles/srep41507

also, it is not necessary for a substance to enter the cell to produce an effect, it can link to a specific receptor on cell surface and start a process leads to cell activation. in addition lipophylic substances can directly across the bilayer lipidic of the plasma membrane to act later in the cytoplasm or in the nucleus

A drug may enter through different vias, such as difussion (liposoluble), carriers (e.g. aminoacids), and endocytosis/transcytocis. The latter may be by adsorption mediated endocytosis/transcytosis (specially drugs positive charged); or receptor mediated endocytosis/transcytosis, where the drug-receptor complex is endocyted. Endocytosis may be by clathrins or caveolae. The term transcytosis is used when the drug come across the cell (e.g. endothelial cells), otherwise is endocytosis.

In the case of nucleus entering, liposoluble drugs usually use intracellular receptor which get into the nucleus (e.g. corticoids), or other auxiliar proteins, which can be cytoskeleton's, or specilized proteins. Virus use proteins, mostly receptors, but also can use proteins for anchorage.

It is noteworthy, that medications, not necessary need to enter the cell to exert effect, nor the nucleus.

Transport of foreign molecule possible through Receptor mediated, passive diffusion, clathrin mediated n or by phagocytosis

thanks for your answers and recommended article.

as I've understood ,drug can trigger a mechanism in its turn , even if it doesn't enter cell or nucleus.

On the other hand ,I think it would be important to enter cell when it comes to anti cancer drugs ,because it will damage the healthy tissue and cells less .

Hi,

Please refer to the attached schemes which explains liposome-cell interaction. More particular answer to your question regarding bioactive delivery to cell nucleus would be considering the role of endoplasmic reticulum.

Source of attached images:

Mozafari, M.R. & Mortazavi, S.M. (2005) Nanoliposomes: From Fundamentals to Recent Developments. Trafford Publishing Ltd, Oxford, UK. ISBN 1-4120-5545-8