{{Distinguish|Cytotoxicity}} {{cs1 config|name-list-style=vanc|display-authors=6}} '''Cytostasis''' (cyto – cell; stasis – stoppage) refers to the inhibition of cell growth and proliferation. A '''cytostatic''' agent is a cellular component or drug that prevents cells from dividing, thereby suppressing proliferation; in some contexts, prolonged cytostasis may lead to cell death.<ref name="Jureczko_2024">{{cite journal | vauthors = Jureczko M, Przystaś W | title = Toxicity toward freshwater and marine water organisms of the cytostatic drugs bleomycin and vincristine and their binary mixture | journal = The Science of the Total Environment | volume = 933 | article-number = 173175 | date = July 2024 | pmid = 38750736 | doi = 10.1016/j.scitotenv.2024.173175 | bibcode = 2024ScTEn.93373175J }}</ref><ref name="Gouveia_2019">{{cite journal | vauthors = Gouveia TI, Alves A, Santos MS | title = New insights on cytostatic drug risk assessment in aquatic environments based on measured concentrations in surface waters | journal = Environment International | volume = 133 | issue = Pt B | article-number = 105236 | date = December 2019 | pmid = 31675568 | doi = 10.1016/j.envint.2019.105236 | hdl-access = free | bibcode = 2019EnInt.13305236G | hdl = 10216/127536 }}</ref>

Cytostasis is essential for the development and maintenance of structured multicellular organisms. Without regulation of cell growth and division, organized tissues and organs would not be possible.{{Citation needed|reason=Why?|date=April 2025}} Cytostatic drugs are widely used in the chemotherapy of cancer, as well as in the treatment of certain skin diseases and infections, although they may also affect normal, healthy cells and tissues.<ref name="Gouveia_2019" /><ref>{{cite journal | vauthors = Brezovšek P, Eleršek T, Filipič M | title = Toxicities of four anti-neoplastic drugs and their binary mixtures tested on the green alga Pseudokirchneriella subcapitata and the cyanobacterium Synechococcus leopoliensis | journal = Water Research | volume = 52 | pages = 168–177 | date = April 2014 | pmid = 24472702 | doi = 10.1016/j.watres.2014.01.007 | bibcode = 2014WatRe..52..168B }}</ref> Certain active hygienic products also contain cytostatic substances.

In practice, cytostatic and cytotoxic mechanisms often occur together, as many agents display both growth-inhibitory and cell-killing effects depending on concentration, exposure time, and cell type. Unlike cytotoxicity, which causes cell death, cytostasis suppresses proliferation without necessarily killing cells.

==Activators== Nitric oxide – activated macrophages produce large amounts of nitric oxide (NO), which induces both cytostasis and cytotoxicity to tumor cells both ''in vitro'' and ''in vivo''. Nitric oxide-induced cytostasis targets ribonucleotide reductase by rapid and reversible inhibition. However, other studies show there could be other targets that are responsible for producing long-lasting cytostasis in cells.<ref name="Pervin_2001">{{cite journal | vauthors = Pervin S, Singh R, Chaudhuri G | title = Nitric oxide-induced cytostasis and cell cycle arrest of a human breast cancer cell line (MDA-MB-231): potential role of cyclin D1 | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 98 | issue = 6 | pages = 3583–3588 | date = March 2001 | pmid = 11248121 | pmc = 30696 | doi = 10.1073/pnas.041603998 | doi-access = free | bibcode = 2001PNAS...98.3583P }}</ref>

Lipopolysaccharide (LPS) and lipid A-associated protein – studies have demonstrated that LPS and LAP are potent macrophage activators that have been shown to stimulate tumoricidal (cytostatic) activity ''in vitro''. LAP and LPS were shown to stimulate C3H/HeJ macrophages to kill target tumor cells. It was concluded that LAP can deliver at least one of the triggering signals necessary for inducing macrophage activity that leads to cytostasis.<ref name="Chapes_1988">{{cite journal | vauthors = Chapes SK, Killion JW, Morrison DC | title = Tumor cell killing and cytostasis by C3H/HeJ macrophages activated in vitro by lipid A-associated protein and interferon gamma | journal = Journal of Leukocyte Biology | volume = 43 | issue = 3 | pages = 232–237 | date = March 1988 | pmid = 3125294 | doi = 10.1002/jlb.43.3.232 | s2cid = 2481166 }}</ref>

Polyunsaturated fatty acid – N-3 and n-6 polyunsaturated fatty acids were found to have a distinct effect on cell growth in certain human urothelial cells. Cystostatic concentrations of n-3 and n-6 PUFA did not induce apoptosis, but did cause permanent cellular growth arrest by effecting the cell cycle. Study shows that metabolites of the lipoxygenase pathway are involved with the antiproliferation induce by PUFA. However, PUFA cytostatic activity is not tumor-specific.<ref name="Diggle_2000">{{cite journal | vauthors = Diggle CP, Pitt E, Roberts P, Trejdosiewicz LK, Southgate J | title = N;-3 and n;-6 polyunsaturated fatty acids induce cytostasis in human urothelial cells independent of p53 gene function | journal = Journal of Lipid Research | volume = 41 | issue = 9 | pages = 1509–1515 | date = September 2000 | pmid = 10974058 | doi = 10.1016/S0022-2275(20)33463-5 | doi-access = free }}</ref>

==Medical uses==

Cytostatic agents have been beneficial in fighting tumors with their ability to induce cell growth arrest. After administration, they are expelled from the body through urine and feces, which ultimately reach wastewater systems, posing a risk to the aquatic ecosystem.<ref name = "Gouveia_2019" /><ref>{{cite book | vauthors = Alygizakis NA, Slobodnik J, Thomaidis NS | chapter = Sources and occurrence of pharmaceutical residues in offshore seawater | pages = 329–350 | date = 2021 | doi = 10.1016/b978-0-08-102971-8.00011-1 | title = Pharmaceuticals in Marine and Coastal Environments | publisher = Elsevier | isbn = 978-0-08-102971-8 }}</ref><ref name = "Jureczko_2024" /><ref>{{cite journal | vauthors = Borchers A, Pieler T | title = Programming pluripotent precursor cells derived from Xenopus embryos to generate specific tissues and organs | journal = Genes | volume = 1 | issue = 3 | pages = 413–426 | date = November 2010 | pmid = 24710095 | doi = 10.3390/w13162222 | pmc = 3966229 | hdl-access = free | doi-access = free | hdl = 11147/11590 }}</ref><ref>{{cite journal | vauthors = Santos MS, Franquet-Griell H, Lacorte S, Madeira LM, Alves A | title = Anticancer drugs in Portuguese surface waters - Estimation of concentrations and identification of potentially priority drugs | journal = Chemosphere | volume = 184 | pages = 1250–1260 | date = October 2017 | pmid = 28672724 | doi = 10.1016/j.chemosphere.2017.06.102 | bibcode = 2017Chmsp.184.1250S }}</ref><ref>{{Cite journal | vauthors = Tauxe-Wuersch A, De Alencastro LF, Grandjean D, Tarradellas J | title = Trace determination of tamoxifen and 5-fluorouracil in hospital and urban wastewaters | journal = International Journal of Environmental Analytical Chemistry | volume = 86 | issue = 7 | pages = 473–485 | date = 2006-06-15 | doi = 10.1080/03067310500291502 | url = http://www.tandfonline.com/doi/abs/10.1080/03067310500291502 | language = en | bibcode = 2006IJEAC..86..473T | issn = 0306-7319 | url-access = subscription }}</ref> Although the risks have not been widely studied and more research is needed in this area.<ref>{{cite journal | vauthors = Franquet-Griell H, Gómez-Canela C, Ventura F, Lacorte S | title = Anticancer drugs: Consumption trends in Spain, prediction of environmental concentrations and potential risks | journal = Environmental Pollution | volume = 229 | pages = 505–515 | date = October 2017 | pmid = 28628866 | doi = 10.1016/j.envpol.2017.06.011 | bibcode = 2017EPoll.229..505F }}</ref><ref>{{Cite journal | vauthors = Martín J, Camacho-Muñoz D, Santos JL, Aparicio I, Alonso E | title = Occurrence and Ecotoxicological Risk Assessment of 14 Cytostatic Drugs in Wastewater | journal = Water, Air, & Soil Pollution | volume = 225 | issue = 3 | article-number = 1896 | date = 2014-02-16 | doi = 10.1007/s11270-014-1896-y | language = en | bibcode = 2014WASP..225.1896M | issn = 1573-2932 }}</ref><ref name = "Gouveia_2019" />

Breast cancer – One study indicates nitric oxide (NO) is able to have a cytostatic effect on the human breast cancer cell line MDA-MB-231. Not only does nitric oxide stop cell growth, the study shows that it can also induce apoptosis after the cancer cells have been exposed to NO over 48 hours.<ref name="Pervin_2001" />

Malignant epithelium – Long-chain polyunsaturated fatty acids inhibit cell division, cause cell cycle arrest, and can induce cell death in malignant epithelial cells from various tissue organs ''in vitro.''<ref name="Diggle_2000" />

== See also == * Chemotherapy

== References == {{Reflist}}

Category:Cellular processes