Editing Folate (section)

====Anti-folate chemotherapy====
Folate is important for cells and tissues that divide rapidly.<ref name="Oldref_2">{{cite journal | vauthors = Kamen B | title = Folate and antifolate pharmacology | journal = Seminars in Oncology | volume = 24 | issue = 5 Suppl 18 | pages = S18-30-S18-39 | date = October 1997 | pmid = 9420019 }}</ref> Cancer cells divide rapidly, and drugs that interfere with folate metabolism are used to treat cancer. The antifolate drug [[methotrexate]] is often used to treat cancer because it inhibits the production of the active tetrahydrofolate (THF) from the inactive dihydrofolate (DHF).<ref name="Gonen_2012">{{cite journal | vauthors = Gonen N, Assaraf YG | title = Antifolates in cancer therapy: structure, activity and mechanisms of drug resistance | journal = Drug Resistance Updates: Reviews and Commentaries in Antimicrobial and Anticancer Chemotherapy | volume = 15 | issue = 4 | pages = 183–210 | date = August 2012 | pmid = 22921318 | doi = 10.1016/j.drup.2012.07.002 }}</ref> However, methotrexate can be toxic,<ref>{{cite journal | vauthors = Rubio IT, Cao Y, Hutchins LF, Westbrook KC, Klimberg VS | title = Effect of glutamine on methotrexate efficacy and toxicity | journal = Annals of Surgery | volume = 227 | issue = 5 | pages = 772–8; discussion 778–80 | date = May 1998 | pmid = 9605669 | pmc = 1191365 | doi = 10.1097/00000658-199805000-00018 }}</ref><ref>{{cite journal | vauthors = Wolff JE, Hauch H, Kühl J, Egeler RM, Jürgens H | title = Dexamethasone increases hepatotoxicity of MTX in children with brain tumors | journal = Anticancer Research | volume = 18 | issue = 4B | pages = 2895–9 | year = 1998 | pmid = 9713483 }}</ref><ref>{{cite journal | vauthors = Kepka L, De Lassence A, Ribrag V, Gachot B, Blot F, Theodore C, Bonnay M, Korenbaum C, Nitenberg G | title = Successful rescue in a patient with high dose methotrexate-induced nephrotoxicity and acute renal failure | journal = Leukemia & Lymphoma | volume = 29 | issue = 1–2 | pages = 205–9 | date = March 1998 | pmid = 9638991 | doi = 10.3109/10428199809058397 }}</ref> producing side effects such as inflammation in the digestive tract that make eating normally more difficult. Bone marrow depression (inducing leukopenia and thrombocytopenia) and acute kidney and liver failure have been reported.

[[Folinic acid]], under the drug name [[leucovorin]], a form of folate (formyl-THF), can help "rescue" or reverse the toxic effects of methotrexate.<ref>{{cite journal | vauthors = Branda RF, Nigels E, Lafayette AR, Hacker M | title = Nutritional folate status influences the efficacy and toxicity of chemotherapy in rats | journal = Blood | volume = 92 | issue = 7 | pages = 2471–6 | date = October 1998 | pmid = 9746787 | doi = 10.1182/blood.V92.7.2471 | doi-access = free }}</ref> Folic acid supplements have little established role in cancer chemotherapy.<ref>{{cite journal | vauthors = Shiroky JB | title = The use of folates concomitantly with low-dose pulse methotrexate | journal = Rheumatic Disease Clinics of North America | volume = 23 | issue = 4 | pages = 969–80 | date = November 1997 | pmid = 9361164 | doi = 10.1016/S0889-857X(05)70369-0 }}</ref><ref>{{cite journal | vauthors = Keshava C, Keshava N, Whong WZ, Nath J, Ong TM | title = Inhibition of methotrexate-induced chromosomal damage by folinic acid in V79 cells | journal = Mutation Research | volume = 397 | issue = 2 | pages = 221–8 | date = February 1998 | pmid = 9541646 | doi = 10.1016/S0027-5107(97)00216-9 | bibcode = 1998MRFMM.397..221K }}</ref> The supplement of folinic acid in people undergoing methotrexate treatment is to give less rapidly dividing cells enough folate to maintain normal cell functions. The amount of folate given is quickly depleted by rapidly dividing (cancer) cells, so this does not negate the effects of methotrexate.