Editing Bcl-2

{{Short description|Protein found in humans}}
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{{Infobox_gene}}
'''Bcl-2''', encoded in humans by the '''''BCL2''''' [[gene]], is the founding member of the [[apoptosis regulator proteins, Bcl-2 family|Bcl-2 family]] of [[regulator protein]]s. BCL2 blocks programmed cell death ([[apoptosis]]) <ref>{{cite journal | vauthors = Hockenbery D, Nuñez G, Milliman C, Schreiber RD, Korsmeyer SJ | title = Bcl-2 is an inner mitochondrial membrane protein that blocks programmed cell death | journal = Nature | volume = 348 | issue = 6299 | pages = 334–336 | date = November 1990 | pmid = 2250705 | doi = 10.1038/348334a0 | bibcode = 1990Natur.348..334H }}</ref> while other BCL2 family members can either inhibit or induce it.<ref name="pmid6093263">{{cite journal | vauthors = Tsujimoto Y, Finger LR, Yunis J, Nowell PC, Croce CM | title = Cloning of the chromosome breakpoint of neoplastic B cells with the t(14;18) chromosome translocation | journal = Science | volume = 226 | issue = 4678 | pages = 1097–1099 | date = November 1984 | pmid = 6093263 | doi = 10.1126/science.6093263 | bibcode = 1984Sci...226.1097T }}</ref><ref name="pmid2875799">{{cite journal | vauthors = Cleary ML, Smith SD, Sklar J | title = Cloning and structural analysis of cDNAs for bcl-2 and a hybrid bcl-2/immunoglobulin transcript resulting from the t(14;18) translocation | journal = Cell | volume = 47 | issue = 1 | pages = 19–28 | date = October 1986 | pmid = 2875799 | doi = 10.1016/0092-8674(86)90362-4 | s2cid = 31493780 | doi-access = free }}</ref> It was the first apoptosis regulator identified in any organism.<ref>{{cite journal |vauthors=Kelly GL, Strasser A |title=Toward Targeting Antiapoptotic MCL-1 for Cancer Therapy |year=2020 |journal=Annual Review of Cancer Biology |volume=4 |pages=299–313  |doi=10.1146/annurev-cancerbio-030419-033510 |doi-access=free|hdl=11343/252362 |hdl-access=free }}</ref>

Bcl-2 derives its name from ''B-cell lymphoma 2'', as it is the second member of a range of proteins initially described in [[chromosomal translocation]]s involving [[chromosome]]s [[Chromosome 14|14]] and [[Chromosome 18|18]] in [[follicular lymphoma]]s. [[Orthologs]]<ref name="OrthoMaM">{{cite web | title = OrthoMaM phylogenetic marker: Bcl-2 coding sequence | url = http://www.orthomam.univ-montp2.fr/orthomam/data/cds/detailMarkers/ENSG00000171791_BCL2.xml | access-date = 20 December 2009 | archive-url = https://web.archive.org/web/20150924061939/http://www.orthomam.univ-montp2.fr/orthomam/data/cds/detailMarkers/ENSG00000171791_BCL2.xml | archive-date = 24 September 2015 | url-status = dead }}</ref> (such as ''Bcl2'' in mice) have been identified in numerous [[mammals]] for which complete [[genome]] data are available.

Like [[BCL3]], BCL5, [[BCL6]], BCL7A, [[BCL9]], and [[BCL10]], it has clinical significance in [[lymphoma]].

== Isoforms ==

The two [[isoforms]] of Bcl-2, Isoform 1, and Isoform 2, exhibit a similar fold. However, results in the ability of these isoforms to bind to the [[Bcl-2-associated death promoter|BAD]] and [[Bcl-2 homologous antagonist killer|BAK]] proteins, as well as in the structural topology and [[electrostatic potential]] of the binding groove, suggest differences in antiapoptotic activity for the two [[Protein isoform|isoforms]].<ref name="Human Bcl2 1G5M">{{PDB|1G5M}}; {{cite journal | vauthors = Petros AM, Medek A, Nettesheim DG, Kim DH, Yoon HS, Swift K, Matayoshi ED, Oltersdorf T, Fesik SW | title = Solution structure of the antiapoptotic protein bcl-2 | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 98 | issue = 6 | pages = 3012–3017 | date = March 2001 | pmid = 11248023 | pmc = 30598 | doi = 10.1073/pnas.041619798 | doi-access = free | bibcode = 2001PNAS...98.3012P }}</ref>

== Function ==

BCL-2 is localized to the outer membrane of [[Mitochondrion|mitochondria]], where it plays an important role in promoting cellular survival and inhibiting the actions of pro-apoptotic proteins. The pro-apoptotic proteins in the BCL-2 family, including [[Bcl-2-associated X protein|Bax]] and [[Bcl-2 homologous antagonist killer|Bak]], normally act on the mitochondrial membrane to promote permeabilization and release of [[cytochrome c]] and [[Reactive oxygen species|ROS]], that are important signals in the apoptosis cascade. These pro-apoptotic proteins are in turn activated by BH3-only proteins, and are inhibited by the function of BCL-2 and its relative [[Bcl-xL|BCL-Xl]].<ref>{{cite journal | vauthors = Hardwick JM, Soane L | title = Multiple functions of BCL-2 family proteins | journal = Cold Spring Harbor Perspectives in Biology | volume = 5 | issue = 2 | pages = a008722 | date = February 2013 | pmid = 23378584 | pmc = 3552500 | doi = 10.1101/cshperspect.a008722 }}</ref>

[[File:Bcl2 inhibition of Bax on mitochondrion.png|300px]]

There are additional non-canonical roles of BCL-2 that are being explored. BCL-2 is known to regulate mitochondrial dynamics, and is involved in the regulation of mitochondrial fusion and fission. Additionally, in pancreatic beta-cells, BCL-2 and BCL-Xl are known to be involved in controlling metabolic activity and insulin secretion, with inhibition of BCL-2/Xl showing increasing metabolic activity,<ref>{{cite journal | vauthors = Luciani DS, White SA, Widenmaier SB, Saran VV, Taghizadeh F, Hu X, Allard MF, Johnson JD | title = Bcl-2 and Bcl-xL suppress glucose signaling in pancreatic β-cells | journal = Diabetes | volume = 62 | issue = 1 | pages = 170–182 | date = January 2013 | pmid = 22933114 | pmc = 3526034 | doi = 10.2337/db11-1464 }}</ref> but also additional ROS production; this suggests it has a protective metabolic effect in conditions of high demand.<ref>{{cite journal | vauthors = Aharoni-Simon M, Shumiatcher R, Yeung A, Shih AZ, Dolinsky VW, Doucette CA, Luciani DS | title = Bcl-2 Regulates Reactive Oxygen Species Signaling and a Redox-Sensitive Mitochondrial Proton Leak in Mouse Pancreatic β-Cells | journal = Endocrinology | volume = 157 | issue = 6 | pages = 2270–2281 | date = June 2016 | pmid = 27070098 | doi = 10.1210/en.2015-1964 | doi-access = free }}</ref>

== Role in disease ==
{{See also|Apoptosis#Implication_in_disease|label 1 = Apoptosis implication in disease}}

Damage to the Bcl-2 gene has been identified as a cause of a number of [[cancer]]s, including [[melanoma]], [[breast cancer|breast]], [[prostate cancer|prostate]], [[chronic lymphocytic leukemia]], and [[lung cancer]], and a possible cause of [[schizophrenia]] and [[autoimmunity]]. It is also a cause of resistance to cancer treatments.<ref name = pmid30544835>{{cite journal | vauthors = García-Aranda M, Pérez-Ruiz E, Redondo M | title = Bcl-2 Inhibition to Overcome Resistance to Chemo- and Immunotherapy | journal = International Journal of Molecular Sciences | volume = 19 | issue = 12 | pages = 3950 | date = December 2018 | pmid = 30544835 | pmc = 6321604 | doi = 10.3390/ijms19123950 | doi-access = free }}</ref>

===Cancer===
Cancer can be seen as a disturbance in the [[homeostatic]] balance between cell growth and cell death. Over-expression of anti-apoptotic genes, and under-expression of pro-apoptotic genes, can result in the lack of cell death that is characteristic of cancer. An example can be seen in [[lymphoma]]s. The over-expression of the anti-apoptotic Bcl-2 protein in lymphocytes alone does not cause cancer. But simultaneous over-expression of Bcl-2 and the proto-oncogene [[myc]] may produce aggressive [[B-cell]] malignancies including lymphoma.<ref name="pmid17179226">{{cite journal | vauthors = Otake Y, Soundararajan S, Sengupta TK, Kio EA, Smith JC, Pineda-Roman M, Stuart RK, Spicer EK, Fernandes DJ | title = Overexpression of nucleolin in chronic lymphocytic leukemia cells induces stabilization of bcl2 mRNA | journal = Blood | volume = 109 | issue = 7 | pages = 3069–3075 | date = April 2007 | pmid = 17179226 | pmc = 1852223 | doi = 10.1182/blood-2006-08-043257 }}</ref> In [[follicular lymphoma]], a [[chromosomal translocation]] commonly occurs between the fourteenth and the eighteenth [[chromosome]]s – t(14;18) – which places the Bcl-2 gene from chromosome 18 next to the [[Immunoglobulin superfamily|immunoglobulin]] heavy chain locus on chromosome 14. This fusion gene is deregulated, leading to the transcription of excessively high levels of Bcl-2.<ref name="pmid3262202">{{cite journal | vauthors = Vaux DL, Cory S, Adams JM | title = Bcl-2 gene promotes haemopoietic cell survival and cooperates with c-myc to immortalize pre-B cells | journal = Nature | volume = 335 | issue = 6189 | pages = 440–442 | date = September 1988 | pmid = 3262202 | doi = 10.1038/335440a0 | s2cid = 23593952 | bibcode = 1988Natur.335..440V }}</ref> This decreases the propensity of these cells for apoptosis. Bcl-2 expression is frequent in [[small cell lung cancer]], accounting for 76% cases in one study.<ref>{{cite journal | vauthors = Kaiser U, Schilli M, Haag U, Neumann K, Kreipe H, Kogan E, Havemann K | title = Expression of bcl-2--protein in small cell lung cancer | journal = Lung Cancer | volume = 15 | issue = 1 | pages = 31–40 | date = August 1996 | pmid = 8865121 | doi = 10.1016/0169-5002(96)00568-5 }}</ref>

===Auto-immune diseases===
[[Apoptosis]] plays an active role in regulating the immune system. When it is functional, it can cause immune unresponsiveness to self-[[antigens]] via both central and peripheral tolerance. In the case of defective apoptosis, it may contribute to etiological aspects of autoimmune diseases.<ref name="pmid17162368">{{cite journal | vauthors = Li A, Ojogho O, Escher A | title = Saving death: apoptosis for intervention in transplantation and autoimmunity | journal = Clinical & Developmental Immunology | volume = 13 | issue = 2–4 | pages = 273–282 | year = 2006 | pmid = 17162368 | pmc = 2270759 | doi = 10.1080/17402520600834704 }}</ref> The autoimmune disease [[Diabetes mellitus type 1|type 1 diabetes]] can be caused by defective apoptosis, which leads to aberrant T cell [[Activation-induced cytidine deaminase|AICD]] and defective peripheral tolerance. Due to the fact that [[dendritic cell]]s are the immune system's most important [[antigen-presenting cell]]s, their activity must be tightly regulated by mechanisms such as apoptosis. Researchers have found that mice containing dendritic cells that are [[BCL2L11|Bim]] -/-, thus unable to induce effective apoptosis, have [[autoimmune disease]]s more so than those that have normal dendritic cells.<ref name="pmid17162368"/> Other studies have shown that dendritic cell lifespan may be partly controlled by a timer dependent on anti-apoptotic Bcl-2.<ref name="pmid17162368"/>

=== Other ===

Apoptosis plays an important role in regulating a variety of diseases. For example, schizophrenia is a psychiatric disorder in which an abnormal ratio of pro- and anti-apoptotic factors may contribute towards pathogenesis.<ref name="pmid16226876">{{cite journal | vauthors = Glantz LA, Gilmore JH, Lieberman JA, Jarskog LF | title = Apoptotic mechanisms and the synaptic pathology of schizophrenia | journal = Schizophrenia Research | volume = 81 | issue = 1 | pages = 47–63 | date = January 2006 | pmid = 16226876 | doi = 10.1016/j.schres.2005.08.014 | s2cid = 22388783 }}</ref> Some evidence suggests that this may result from abnormal expression of Bcl-2 and increased expression of [[Caspase 3|caspase-3]].<ref name="pmid16226876"/>

== Diagnostic use ==

Antibodies to Bcl-2 can be used with [[immunohistochemistry]] to identify cells containing the antigen. In healthy tissue, these antibodies react with B-cells in the [[mantle zone]], as well as some [[T-cell]]s. However, positive cells increase considerably in [[follicular lymphoma]], as well as many other forms of cancer. In some cases, the presence or absence of Bcl-2 staining in [[biopsy|biopsies]] may be significant for the patient's [[prognosis]] or likelihood of [[relapse]].<ref name=Leong>{{cite book | veditors = Chetty R, Cooper K, Gown AM |year=2016 | chapter =  Section 1 - Antibodies: Bcl-2 |title=Manual of Diagnostic Cytology |edition=2nd |publisher=Greenwich Medical Media, Ltd.|pages=23–24 | doi = 10.1017/9781139939508.013 |isbn=978-1-139-93950-8 }}</ref>

== Targeted therapies ==

Targeted and selective Bcl-2 inhibitors that have been in development or are currently in the clinic include:

===Oblimersen===
An antisense [[oligonucleotide]] drug, [[oblimersen]] (G3139), was developed by [[Genta (company)|Genta Incorporated]] to target Bcl-2. An [[antisense]] DNA or RNA strand is non-coding and complementary to the coding strand (which is the template for producing respectively RNA or protein). An [[antisense drugs|antisense drug]] is a short sequence of modified DNA that hybridises with and inactivates mRNA, preventing the [[protein]] from being formed.{{cn|date=November 2024}}

Human [[lymphoma]] [[cell (biology)|cell]] proliferation (with t(14;18) translocation) could be inhibited by [[antisense oligonucleotide]] targeted at the start [[codon]] region of Bcl-2 [[mRNA]]. ''[[In vitro]]'' studies led to the identification of Genasense, which is complementary to the first 6 codons of Bcl-2 mRNA.<ref name="pmid12445555">{{cite journal | vauthors = Dias N, Stein CA | title = Potential roles of antisense oligonucleotides in cancer therapy. The example of Bcl-2 antisense oligonucleotides | journal = European Journal of Pharmaceutics and Biopharmaceutics | volume = 54 | issue = 3 | pages = 263–269 | date = November 2002 | pmid = 12445555 | doi = 10.1016/S0939-6411(02)00060-7 }}</ref>

These showed successful results in Phase I/II trials for lymphoma. A large Phase III trial was launched in 2004.<ref name="pmid15010151">{{cite journal | vauthors = Mavromatis BH, Cheson BD | title = Novel therapies for chronic lymphocytic leukemia | journal = Blood Reviews | volume = 18 | issue = 2 | pages = 137–148 | date = June 2004 | pmid = 15010151 | doi = 10.1016/S0268-960X(03)00039-0 }}</ref> As of 2016, the drug had not been approved and its developer was out of business.<ref>{{Cite web|title = Genasense (oblimersen sodium) FDA Approval Status | work = Drugs.com|url = https://www.drugs.com/history/genasense.html |access-date = 2016-02-11}}</ref>

===ABT-737 and navitoclax (ABT-263)===

In the mid-2000s, [[Abbott Laboratories]] developed a novel inhibitor of Bcl-2, [[Bcl-xL]] and Bcl-w, known as [[ABT-737]]. This compound is part of a group of BH3 mimetic small molecule inhibitors (SMI) that target these Bcl-2 family proteins, but not A1 or [[MCL1|Mcl-1]]. ABT-737 is superior to previous BCL-2 inhibitors given its higher affinity for Bcl-2, Bcl-xL and Bcl-w. ''In vitro'' studies showed that primary cells from patients with B-cell malignancies are sensitive to ABT-737.<ref>{{cite journal | vauthors = Vogler M, Dinsdale D, Dyer MJ, Cohen GM | title = Bcl-2 inhibitors: small molecules with a big impact on cancer therapy | journal = Cell Death and Differentiation | volume = 16 | issue = 3 | pages = 360–367 | date = March 2009 | pmid = 18806758 | doi = 10.1038/cdd.2008.137 | hdl-access = free | s2cid = 24538054 | doi-access = free | hdl = 2381/4756 }}</ref>

In animal models, it improves survival, causes tumor regression and cures a high percentage of mice.<ref>{{cite journal | vauthors = Oltersdorf T, Elmore SW, Shoemaker AR, Armstrong RC, Augeri DJ, Belli BA, Bruncko M, Deckwerth TL, Dinges J, Hajduk PJ, Joseph MK, Kitada S, Korsmeyer SJ, Kunzer AR, Letai A, Li C, Mitten MJ, Nettesheim DG, Ng S, Nimmer PM, O'Connor JM, Oleksijew A, Petros AM, Reed JC, Shen W, Tahir SK, Thompson CB, Tomaselli KJ, Wang B, Wendt MD, Zhang H, Fesik SW, Rosenberg SH | title = An inhibitor of Bcl-2 family proteins induces regression of solid tumours | journal = Nature | volume = 435 | issue = 7042 | pages = 677–681 | date = June 2005 | pmid = 15902208 | doi = 10.1038/nature03579 | s2cid = 4335635 | bibcode = 2005Natur.435..677O }}</ref> In preclinical studies utilizing [[Patient derived tumor xenografts|patient xenografts]], ABT-737 showed efficacy for treating lymphoma and other blood cancers.<ref>{{cite journal | vauthors = Hann CL, Daniel VC, Sugar EA, Dobromilskaya I, Murphy SC, Cope L, Lin X, Hierman JS, Wilburn DL, Watkins DN, Rudin CM | title = Therapeutic efficacy of ABT-737, a selective inhibitor of BCL-2, in small cell lung cancer | journal = Cancer Research | volume = 68 | issue = 7 | pages = 2321–2328 | date = April 2008 | pmid = 18381439 | pmc = 3159963 | doi = 10.1158/0008-5472.can-07-5031 }}</ref> Because of its unfavorable pharmacologic properties ABT-737 is not appropriate for clinical trials, while its orally [[Bioavailability|bioavailable]] derivative [[navitoclax]] (ABT-263) has similar activity on [[small cell lung cancer]] (SCLC) cell lines and has entered clinical trials.<ref name="hauck2009">{{cite journal | vauthors = Hauck P, Chao BH, Litz J, Krystal GW | title = Alterations in the Noxa/Mcl-1 axis determine sensitivity of small cell lung cancer to the BH3 mimetic ABT-737 | journal = Molecular Cancer Therapeutics | volume = 8 | issue = 4 | pages = 883–892 | date = April 2009 | pmid = 19372561 | doi = 10.1158/1535-7163.MCT-08-1118 | s2cid = 19245418 | doi-access =  }}</ref> While clinical responses with navitoclax were promising, mechanistic dose-limiting [[thrombocytopenia]] was observed in patients under treatment due to Bcl-xL inhibition in [[platelet]]s.<ref>{{cite journal | vauthors = Gandhi L, Camidge DR, Ribeiro de Oliveira M, Bonomi P, Gandara D, Khaira D, Hann CL, McKeegan EM, Litvinovich E, Hemken PM, Dive C, Enschede SH, Nolan C, Chiu YL, Busman T, Xiong H, Krivoshik AP, Humerickhouse R, Shapiro GI, Rudin CM | title = Phase I study of Navitoclax (ABT-263), a novel Bcl-2 family inhibitor, in patients with small-cell lung cancer and other solid tumors | journal = Journal of Clinical Oncology | volume = 29 | issue = 7 | pages = 909–916 | date = March 2011 | pmid = 21282543 | pmc = 4668282 | doi = 10.1200/JCO.2010.31.6208 }}</ref><ref>{{cite journal | vauthors = Rudin CM, Hann CL, Garon EB, Ribeiro de Oliveira M, Bonomi PD, Camidge DR, Chu Q, Giaccone G, Khaira D, Ramalingam SS, Ranson MR, Dive C, McKeegan EM, Chyla BJ, Dowell BL, Chakravartty A, Nolan CE, Rudersdorf N, Busman TA, Mabry MH, Krivoshik AP, Humerickhouse RA, Shapiro GI, Gandhi L | title = Phase II study of single-agent navitoclax (ABT-263) and biomarker correlates in patients with relapsed small cell lung cancer | journal = Clinical Cancer Research | volume = 18 | issue = 11 | pages = 3163–3169 | date = June 2012 | pmid = 22496272 | pmc = 3715059 | doi = 10.1158/1078-0432.CCR-11-3090 }}</ref><ref>{{cite journal | vauthors = Kaefer A, Yang J, Noertersheuser P, Mensing S, Humerickhouse R, Awni W, Xiong H | title = Mechanism-based pharmacokinetic/pharmacodynamic meta-analysis of navitoclax (ABT-263) induced thrombocytopenia | journal = Cancer Chemotherapy and Pharmacology | volume = 74 | issue = 3 | pages = 593–602 | date = September 2014 | pmid = 25053389 | doi = 10.1007/s00280-014-2530-9 | s2cid = 10685695 }}</ref>

===Venetoclax (ABT-199)===
Due to dose-limiting thrombocytopenia of navitoclax as a result of Bcl-xL inhibition, [[Abbvie]] successfully developed the highly selective inhibitor [[venetoclax]] (ABT-199), which inhibits Bcl-2, but not Bcl-xL or Bcl-w.<ref>{{cite journal | vauthors = Pan R, Hogdal LJ, Benito JM, Bucci D, Han L, Borthakur G, Cortes J, DeAngelo DJ, Debose L, Mu H, Döhner H, Gaidzik VI, Galinsky I, Golfman LS, Haferlach T, Harutyunyan KG, Hu J, Leverson JD, Marcucci G, Müschen M, Newman R, Park E, Ruvolo PP, Ruvolo V, Ryan J, Schindela S, Zweidler-McKay P, Stone RM, Kantarjian H, Andreeff M, Konopleva M, Letai AG | title = Selective BCL-2 inhibition by ABT-199 causes on-target cell death in acute myeloid leukemia | journal = Cancer Discovery | volume = 4 | issue = 3 | pages = 362–375 | date = March 2014 | pmid = 24346116 | pmc = 3975047 | doi = 10.1158/2159-8290.CD-13-0609 }}</ref> Clinical trials studied the effects of venetoclax, a BH3-mimetic drug designed to block the function of the Bcl-2 protein, on patients with [[chronic lymphocytic leukemia]] (CLL).<ref>{{cite news |title=ABT-199 BH-3 Mimetic Enters Phase Ia Trial For Chronic Lymphocytic Leukemia |first=Grace |last=Liao |date=12 August 2011 |url=http://www.asianscientist.com/tech-pharma/abt-199-bh-3-mimetic-wehi-phase-ia-trial-chronic-lymphocytic-leukemia |publisher=Asian Scientist |access-date=11 February 2016 |url-status=dead |archive-url=https://web.archive.org/web/20120718151431/http://www.asianscientist.com/tech-pharma/abt-199-bh-3-mimetic-wehi-phase-ia-trial-chronic-lymphocytic-leukemia/ |archive-date=18 July 2012 |df=dmy }}</ref><ref name=":0">{{cite journal | vauthors = Roberts AW, Davids MS, Pagel JM, Kahl BS, Puvvada SD, Gerecitano JF, Kipps TJ, Anderson MA, Brown JR, Gressick L, Wong S, Dunbar M, Zhu M, Desai MB, Cerri E, Heitner Enschede S, Humerickhouse RA, Wierda WG, Seymour JF | title = Targeting BCL2 with Venetoclax in Relapsed Chronic Lymphocytic Leukemia | journal = The New England Journal of Medicine | volume = 374 | issue = 4 | pages = 311–322 | date = January 2016 | pmid = 26639348 | pmc = 7107002 | doi = 10.1056/NEJMoa1513257 | doi-access = free }}</ref> Good responses have been reported and thrombocytopenia was no longer observed.<ref name=":0" /><ref>{{cite web|url=http://www.stokesentinel.co.uk/Miracle-drug-cured-cancer-Amazing-recovery/story-21080535-detail/story.html|title='Miracle drug cured my cancer!': Amazing three-week recovery of Staffordshire sufferer|work=Stoke Sentinel|access-date=10 May 2014|archive-url=https://web.archive.org/web/20140512200023/http://www.stokesentinel.co.uk/Miracle-drug-cured-cancer-Amazing-recovery/story-21080535-detail/story.html|archive-date=12 May 2014|url-status=dead|df=dmy-all}}</ref> A phase 3 trial started in Dec 2015.<ref name=ASH2015-V>{{cite web|url=http://www.medpagetoday.com/MeetingCoverage/ASHHematology/55056|title=Hard-to-Treat CLL Yields to Investigational Drug| first = Michael | last = Smith |date=7 December 2015 }}</ref>
It was approved by the [[US FDA]] in April 2016 as a second-line treatment for CLL associated with 17-p deletion.<ref name=Bankhead2016>{{cite news |last1=Bankhead |first1=Charles |title=FDA Approves AbbVie's BCL-2 Targeting Drug for CLL |url=https://www.medpagetoday.com/hematologyoncology/leukemia/57298 |work=Medpage Today |date=11 April 2016 |language=en}}</ref> This was the first FDA approval of a BCL-2 inhibitor.<ref name=Bankhead2016/> In June 2018, the FDA broadened the approval for anyone with CLL or small lymphocytic lymphoma, with or without 17p deletion, still as a second-line treatment.<ref>{{cite web|title=FDA approves venetoclax for CLL or SLL, with or without 17p deletion, after one prior therapy|date=24 March 2020 |url=https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm495253.htm|archive-url=https://web.archive.org/web/20160414103245/http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm495253.htm|url-status=dead|archive-date=14 April 2016|publisher=U.S. Food and Drug Administration|language=en}}</ref>

===Sonrotoclax (BGB-11417)===
Venetoclax drug resistance has been noted with the G101V mutation in BCL-2 observed in relapsing patients.<ref>{{cite journal | vauthors = Blombery P, Anderson MA, Gong JN, Thijssen R, Birkinshaw RW, Thompson ER, Teh CE, Nguyen T, Xu Z, Flensburg C, Lew TE, Majewski IJ, Gray DH, Westerman DA, Tam CS, Seymour JF, Czabotar PE, Huang DC, Roberts AW | title = Acquisition of the Recurrent Gly101Val Mutation in BCL2 Confers Resistance to Venetoclax in Patients with Progressive Chronic Lymphocytic Leukemia | journal = Cancer Discovery | volume = 9 | issue = 3 | pages = 342–353 | date = March 2019 | pmid = 30514704 | doi = 10.1158/2159-8290.CD-18-1119 }}</ref> [[Sonrotoclax]] shows greater tumor growth inhibition in hematologic tumor models than venetoclax and inhibits venetoclax-resistant BCL-2 variants. Sonrotoclax is under clinical investigation as a monotherapy and in combination with other anticancer agents.<ref>{{cite journal | vauthors = Liu J, Li S, Wang Q, Feng Y, Xing H, Yang X, Guo Y, Guo Y, Sun H, Liu X, Yang S, Mei Z, Zhu Y, Cheng Z, Chen S, Xu M, Zhang W, Wan N, Wang J, Ma Y, Zhang S, Luan X, Xu A, Li L, Wang H, Yang X, Hong Y, Xue H, Yuan X, Hu N, Song X, Wang Z, Liu X, Wang L, Liu Y | title = Sonrotoclax overcomes BCL2 G101V mutation-induced venetoclax resistance in preclinical models of hematologic malignancy | journal = Blood | volume = 143 | issue = 18 | pages = 1825–1836 | date = May 2024 | pmid = 38211332 | pmc = 11076911 | doi = 10.1182/blood.2023019706 }}</ref>
**[[Lisaftoclax]]

== Interactions ==

[[Image:Signal transduction pathways.svg|thumb|right|550px|Overview of signal transduction pathways involved in [[apoptosis]]]]
Bcl-2 has been shown to [[Protein-protein interaction|interact]] with:
{{colbegin|colwidth=22em}}
* [[BAK1]],<ref name = pmid14980220>{{cite journal | vauthors = Lin B, Kolluri SK, Lin F, Liu W, Han YH, Cao X, Dawson MI, Reed JC, Zhang XK | title = Conversion of Bcl-2 from protector to killer by interaction with nuclear orphan receptor Nur77/TR3 | journal = Cell | volume = 116 | issue = 4 | pages = 527–540 | date = February 2004 | pmid = 14980220 | doi = 10.1016/s0092-8674(04)00162-x | s2cid = 17808479 | doi-access = free }}</ref><ref name = pmid11728179>{{cite journal | vauthors = Enyedy IJ, Ling Y, Nacro K, Tomita Y, Wu X, Cao Y, Guo R, Li B, Zhu X, Huang Y, Long YQ, Roller PP, Yang D, Wang S | title = Discovery of small-molecule inhibitors of Bcl-2 through structure-based computer screening | journal = Journal of Medicinal Chemistry | volume = 44 | issue = 25 | pages = 4313–4324 | date = December 2001 | pmid = 11728179 | doi = 10.1021/jm010016f }}</ref>
* [[BCAP31]],<ref name = pmid9334338>{{cite journal | vauthors = Ng FW, Nguyen M, Kwan T, Branton PE, Nicholson DW, Cromlish JA, Shore GC | title = p28 Bap31, a Bcl-2/Bcl-XL- and procaspase-8-associated protein in the endoplasmic reticulum | journal = The Journal of Cell Biology | volume = 139 | issue = 2 | pages = 327–338 | date = October 1997 | pmid = 9334338 | pmc = 2139787 | doi = 10.1083/jcb.139.2.327 }}</ref>
* [[BCL2-like 1 (gene)|BCL2-like 1]],<ref name = pmid14980220/><ref name = pmid12137781>{{cite journal | vauthors = Zhang H, Nimmer P, Rosenberg SH, Ng SC, Joseph M | title = Development of a high-throughput fluorescence polarization assay for Bcl-x(L) | journal = Analytical Biochemistry | volume = 307 | issue = 1 | pages = 70–75 | date = August 2002 | pmid = 12137781 | doi = 10.1016/s0003-2697(02)00028-3 }}</ref>
* [[BCL2L11]],<ref name = pmid15694340/><ref name = pmid9430630>{{cite journal | vauthors = O'Connor L, Strasser A, O'Reilly LA, Hausmann G, Adams JM, Cory S, Huang DC | title = Bim: a novel member of the Bcl-2 family that promotes apoptosis | journal = The EMBO Journal | volume = 17 | issue = 2 | pages = 384–395 | date = January 1998 | pmid = 9430630 | pmc = 1170389 | doi = 10.1093/emboj/17.2.384 }}</ref><ref name = pmid9731710>{{cite journal | vauthors = Hsu SY, Lin P, Hsueh AJ | title = BOD (Bcl-2-related ovarian death gene) is an ovarian BH3 domain-containing proapoptotic Bcl-2 protein capable of dimerization with diverse antiapoptotic Bcl-2 members | journal = Molecular Endocrinology | volume = 12 | issue = 9 | pages = 1432–1440 | date = September 1998 | pmid = 9731710 | doi = 10.1210/mend.12.9.0166 | doi-access = free }}</ref>
* [[BECN1]],<ref name = pmid9765397>{{cite journal | vauthors = Liang XH, Kleeman LK, Jiang HH, Gordon G, Goldman JE, Berry G, Herman B, Levine B | title = Protection against fatal Sindbis virus encephalitis by beclin, a novel Bcl-2-interacting protein | journal = Journal of Virology | volume = 72 | issue = 11 | pages = 8586–8596 | date = November 1998 | pmid = 9765397 | pmc = 110269 | doi = 10.1128/JVI.72.11.8586-8596.1998 }}</ref>
* [[BH3 interacting domain death agonist|BID]],<ref name = pmid15694340/><ref name = pmid15520201>{{cite journal | vauthors = Real PJ, Cao Y, Wang R, Nikolovska-Coleska Z, Sanz-Ortiz J, Wang S, Fernandez-Luna JL | title = Breast cancer cells can evade apoptosis-mediated selective killing by a novel small molecule inhibitor of Bcl-2 | journal = Cancer Research | volume = 64 | issue = 21 | pages = 7947–7953 | date = November 2004 | pmid = 15520201 | doi = 10.1158/0008-5472.CAN-04-0945 | s2cid = 11807428 | doi-access =  }}</ref>
* [[BMF (gene)|BMF]],<ref name = pmid11546872>{{cite journal | vauthors = Puthalakath H, Villunger A, O'Reilly LA, Beaumont JG, Coultas L, Cheney RE, Huang DC, Strasser A | title = Bmf: a proapoptotic BH3-only protein regulated by interaction with the myosin V actin motor complex, activated by anoikis | journal = Science | volume = 293 | issue = 5536 | pages = 1829–1832 | date = September 2001 | pmid = 11546872 | doi = 10.1126/science.1062257 | s2cid = 5638023 | bibcode = 2001Sci...293.1829P }}</ref>
* [[BNIP2]],<ref name = pmid12901880/><ref name = pmid7954800>{{cite journal | vauthors = Boyd JM, Malstrom S, Subramanian T, Venkatesh LK, Schaeper U, Elangovan B, D'Sa-Eipper C, Chinnadurai G | title = Adenovirus E1B 19 kDa and Bcl-2 proteins interact with a common set of cellular proteins | journal = Cell | volume = 79 | issue = 2 | pages = 341–351 | date = October 1994 | pmid = 7954800 | doi = 10.1016/0092-8674(94)90202-X | s2cid = 38609845 }}</ref>
* [[BNIP3]],<ref name = pmid7954800/><ref name = pmid10625696>{{cite journal | vauthors = Ray R, Chen G, Vande Velde C, Cizeau J, Park JH, Reed JC, Gietz RD, Greenberg AH | title = BNIP3 heterodimerizes with Bcl-2/Bcl-X(L) and induces cell death independent of a Bcl-2 homology 3 (BH3) domain at both mitochondrial and nonmitochondrial sites | journal = The Journal of Biological Chemistry | volume = 275 | issue = 2 | pages = 1439–1448 | date = January 2000 | pmid = 10625696 | doi = 10.1074/jbc.275.2.1439 | doi-access = free }}</ref>
* [[BNIPL]],<ref name = pmid12901880>{{cite journal | vauthors = Qin W, Hu J, Guo M, Xu J, Li J, Yao G, Zhou X, Jiang H, Zhang P, Shen L, Wan D, Gu J | title = BNIPL-2, a novel homologue of BNIP-2, interacts with Bcl-2 and Cdc42GAP in apoptosis | journal = Biochemical and Biophysical Research Communications | volume = 308 | issue = 2 | pages = 379–385 | date = August 2003 | pmid = 12901880 | doi = 10.1016/s0006-291x(03)01387-1 }}</ref><ref name = pmid9973195>{{cite journal | vauthors = Yasuda M, Han JW, Dionne CA, Boyd JM, Chinnadurai G | title = BNIP3alpha: a human homolog of mitochondrial proapoptotic protein BNIP3 | journal = Cancer Research | volume = 59 | issue = 3 | pages = 533–537 | date = February 1999 | pmid = 9973195 | url = http://cancerres.aacrjournals.org/cgi/pmidlookup?view=long&pmid=9973195 }}</ref>
* [[Bcl-2-associated death promoter|BAD]]<ref name = pmid15694340/><ref name = pmid7834748>{{cite journal | vauthors = Yang E, Zha J, Jockel J, Boise LH, Thompson CB, Korsmeyer SJ | title = Bad, a heterodimeric partner for Bcl-XL and Bcl-2, displaces Bax and promotes cell death | journal = Cell | volume = 80 | issue = 2 | pages = 285–291 | date = January 1995 | pmid = 7834748 | doi = 10.1016/0092-8674(95)90411-5 | s2cid = 10343291 | doi-access = free }}</ref>
* [[Bcl-2-associated X protein|BAX]],<ref name = pmid14980220/><ref name = pmid10620799/><ref name = pmid15231068>{{cite journal | vauthors = Hoetelmans RW | title = Nuclear partners of Bcl-2: Bax and PML | journal = DNA and Cell Biology | volume = 23 | issue = 6 | pages = 351–354 | date = June 2004 | pmid = 15231068 | doi = 10.1089/104454904323145236 }}</ref><ref name = pmid8358790>{{cite journal | vauthors = Oltvai ZN, Milliman CL, Korsmeyer SJ | title = Bcl-2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programmed cell death | journal = Cell | volume = 74 | issue = 4 | pages = 609–619 | date = August 1993 | pmid = 8358790 | doi = 10.1016/0092-8674(93)90509-O | s2cid = 31151334 }}</ref>
* [[Bcl-2-interacting killer|BIK]],<ref name = pmid15694340>{{cite journal | vauthors = Chen L, Willis SN, Wei A, Smith BJ, Fletcher JI, Hinds MG, Colman PM, Day CL, Adams JM, Huang DC | title = Differential targeting of prosurvival Bcl-2 proteins by their BH3-only ligands allows complementary apoptotic function | journal = Molecular Cell | volume = 17 | issue = 3 | pages = 393–403 | date = February 2005 | pmid = 15694340 | doi = 10.1016/j.molcel.2004.12.030 | doi-access = free }}</ref><ref name = pmid12853473>{{cite journal | vauthors = Gillissen B, Essmann F, Graupner V, Stärck L, Radetzki S, Dörken B, Schulze-Osthoff K, Daniel PT | title = Induction of cell death by the BH3-only Bcl-2 homolog Nbk/Bik is mediated by an entirely Bax-dependent mitochondrial pathway | journal = The EMBO Journal | volume = 22 | issue = 14 | pages = 3580–3590 | date = July 2003 | pmid = 12853473 | pmc = 165613 | doi = 10.1093/emboj/cdg343 }}</ref>
* [[C-Raf]],<ref name = pmid8929532>{{cite journal | vauthors = Wang HG, Rapp UR, Reed JC | title = Bcl-2 targets the protein kinase Raf-1 to mitochondria | journal = Cell | volume = 87 | issue = 4 | pages = 629–638 | date = November 1996 | pmid = 8929532 | doi = 10.1016/s0092-8674(00)81383-5 | s2cid = 16559750 | doi-access = free }}</ref>
* [[CAPN2]],<ref name = pmid12000759>{{cite journal | vauthors = Gil-Parrado S, Fernández-Montalván A, Assfalg-Machleidt I, Popp O, Bestvater F, Holloschi A, Knoch TA, Auerswald EA, Welsh K, Reed JC, Fritz H, Fuentes-Prior P, Spiess E, Salvesen GS, Machleidt W | title = Ionomycin-activated calpain triggers apoptosis. A probable role for Bcl-2 family members | journal = The Journal of Biological Chemistry | volume = 277 | issue = 30 | pages = 27217–27226 | date = July 2002 | pmid = 12000759 | doi = 10.1074/jbc.M202945200 | doi-access = free }}</ref>
* [[Caspase 8|CASP8]],<ref name = pmid11406564>{{cite journal | vauthors = Poulaki V, Mitsiades N, Romero ME, Tsokos M | title = Fas-mediated apoptosis in neuroblastoma requires mitochondrial activation and is inhibited by FLICE inhibitor protein and Bcl-2 | journal = Cancer Research | volume = 61 | issue = 12 | pages = 4864–4872 | date = June 2001 | pmid = 11406564 }}</ref><ref name = pmid11832478>{{cite journal | vauthors = Guo Y, Srinivasula SM, Druilhe A, Fernandes-Alnemri T, Alnemri ES | title = Caspase-2 induces apoptosis by releasing proapoptotic proteins from mitochondria | journal = The Journal of Biological Chemistry | volume = 277 | issue = 16 | pages = 13430–13437 | date = April 2002 | pmid = 11832478 | doi = 10.1074/jbc.M108029200 | doi-access = free }}</ref>
* [[Cdk1]],<ref name = pmid11774038>{{cite journal | vauthors = Pathan N, Aime-Sempe C, Kitada S, Basu A, Haldar S, Reed JC | title = Microtubule-targeting drugs induce bcl-2 phosphorylation and association with Pin1 | journal = Neoplasia | volume = 3 | issue = 6 | pages = 550–559 | year = 2001 | pmid = 11774038 | pmc = 1506558 | doi = 10.1038/sj.neo.7900213 }}</ref><ref name = pmid11326318>{{cite journal | vauthors = Pathan N, Aime-Sempe C, Kitada S, Haldar S, Reed JC | title = Microtubule-targeting drugs induce Bcl-2 phosphorylation and association with Pin1 | journal = Neoplasia | volume = 3 | issue = 1 | pages = 70–79 | year = 2001 | pmid = 11326318 | pmc = 1505024 | doi = 10.1038/sj.neo.7900131 }}</ref>
* [[HRK (gene)|HRK]],<ref name = pmid15694340/><ref name = pmid9130713>{{cite journal | vauthors = Inohara N, Ding L, Chen S, Núñez G | title = harakiri, a novel regulator of cell death, encodes a protein that activates apoptosis and interacts selectively with survival-promoting proteins Bcl-2 and Bcl-X(L) | journal = The EMBO Journal | volume = 16 | issue = 7 | pages = 1686–1694 | date = April 1997 | pmid = 9130713 | pmc = 1169772 | doi = 10.1093/emboj/16.7.1686 }}</ref>
* [[IRS1]],<ref name = pmid10679027>{{cite journal | vauthors = Ueno H, Kondo E, Yamamoto-Honda R, Tobe K, Nakamoto T, Sasaki K, Mitani K, Furusaka A, Tanaka T, Tsujimoto Y, Kadowaki T, Hirai H | title = Association of insulin receptor substrate proteins with Bcl-2 and their effects on its phosphorylation and antiapoptotic function | journal = Molecular Biology of the Cell | volume = 11 | issue = 2 | pages = 735–746 | date = February 2000 | pmid = 10679027 | pmc = 14806 | doi = 10.1091/mbc.11.2.735 }}</ref>
* [[Myc]],<ref name = pmid15210690>{{cite journal | vauthors = Jin Z, Gao F, Flagg T, Deng X | title = Tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone promotes functional cooperation of Bcl2 and c-Myc through phosphorylation in regulating cell survival and proliferation | journal = The Journal of Biological Chemistry | volume = 279 | issue = 38 | pages = 40209–40219 | date = September 2004 | pmid = 15210690 | doi = 10.1074/jbc.M404056200 | doi-access = free }}</ref>
* [[Nerve Growth factor IB|NR4A1]],<ref name = pmid14980220/>
* [[Noxa]],<ref name = pmid15694340/><ref name = pmid10807576>{{cite journal | vauthors = Oda E, Ohki R, Murasawa H, Nemoto J, Shibue T, Yamashita T, Tokino T, Taniguchi T, Tanaka N | title = Noxa, a BH3-only member of the Bcl-2 family and candidate mediator of p53-induced apoptosis | journal = Science | volume = 288 | issue = 5468 | pages = 1053–1058 | date = May 2000 | pmid = 10807576 | doi = 10.1126/science.288.5468.1053 | bibcode = 2000Sci...288.1053O }}</ref>
* [[PPP2CA]],<ref name = pmid9852076>{{cite journal | vauthors = Deng X, Ito T, Carr B, Mumby M, May WS | title = Reversible phosphorylation of Bcl2 following interleukin 3 or bryostatin 1 is mediated by direct interaction with protein phosphatase 2A | journal = The Journal of Biological Chemistry | volume = 273 | issue = 51 | pages = 34157–34163 | date = December 1998 | pmid = 9852076 | doi = 10.1074/jbc.273.51.34157 | doi-access = free }}</ref>
* [[PSEN1]],<ref name = pmid10521466>{{cite journal | vauthors = Alberici A, Moratto D, Benussi L, Gasparini L, Ghidoni R, Gatta LB, Finazzi D, Frisoni GB, Trabucchi M, Growdon JH, Nitsch RM, Binetti G | title = Presenilin 1 protein directly interacts with Bcl-2 | journal = The Journal of Biological Chemistry | volume = 274 | issue = 43 | pages = 30764–30769 | date = October 1999 | pmid = 10521466 | doi = 10.1074/jbc.274.43.30764 | doi-access = free }}</ref>
* [[RAD9A]],<ref name = pmid10620799>{{cite journal | vauthors = Komatsu K, Miyashita T, Hang H, Hopkins KM, Zheng W, Cuddeback S, Yamada M, Lieberman HB, Wang HG | title = Human homologue of S. pombe Rad9 interacts with BCL-2/BCL-xL and promotes apoptosis | journal = Nature Cell Biology | volume = 2 | issue = 1 | pages = 1–6 | date = January 2000 | pmid = 10620799 | doi = 10.1038/71316 | s2cid = 52847351 }}</ref>
* [[RRAS]],<ref name = pmid8232588>{{cite journal | vauthors = Fernandez-Sarabia MJ, Bischoff JR | title = Bcl-2 associates with the ras-related protein R-ras p23 | journal = Nature | volume = 366 | issue = 6452 | pages = 274–275 | date = November 1993 | pmid = 8232588 | doi = 10.1038/366274a0 | s2cid = 4312803 | bibcode = 1993Natur.366..274F }}</ref>
* [[Reticulon 4|RTN4]],<ref name = pmid11126360>{{cite journal | vauthors = Tagami S, Eguchi Y, Kinoshita M, Takeda M, Tsujimoto Y | title = A novel protein, RTN-XS, interacts with both Bcl-XL and Bcl-2 on endoplasmic reticulum and reduces their anti-apoptotic activity | journal = Oncogene | volume = 19 | issue = 50 | pages = 5736–5746 | date = November 2000 | pmid = 11126360 | doi = 10.1038/sj.onc.1203948 | doi-access = free }}</ref>
* [[SMN1]],<ref name = pmid9389483>{{cite journal | vauthors = Iwahashi H, Eguchi Y, Yasuhara N, Hanafusa T, Matsuzawa Y, Tsujimoto Y | title = Synergistic anti-apoptotic activity between Bcl-2 and SMN implicated in spinal muscular atrophy | journal = Nature | volume = 390 | issue = 6658 | pages = 413–417 | date = November 1997 | pmid = 9389483 | doi = 10.1038/37144 | s2cid = 1936633 | bibcode = 1997Natur.390..413I }}</ref>
* [[SOD1]],<ref name = pmid15233914>{{cite journal | vauthors = Pasinelli P, Belford ME, Lennon N, Bacskai BJ, Hyman BT, Trotti D, Brown RH | title = Amyotrophic lateral sclerosis-associated SOD1 mutant proteins bind and aggregate with Bcl-2 in spinal cord mitochondria | journal = Neuron | volume = 43 | issue = 1 | pages = 19–30 | date = July 2004 | pmid = 15233914 | doi = 10.1016/j.neuron.2004.06.021 | s2cid = 18141051 | doi-access = free }}</ref> and
* [[TP53BP2]].<ref name = pmid8668206>{{cite journal | vauthors = Naumovski L, Cleary ML | title = The p53-binding protein 53BP2 also interacts with Bc12 and impedes cell cycle progression at G2/M | journal = Molecular and Cellular Biology | volume = 16 | issue = 7 | pages = 3884–3892 | date = July 1996 | pmid = 8668206 | pmc = 231385 | doi = 10.1128/MCB.16.7.3884 }}</ref>
{{colend}}

== See also ==
{{Div col}}
* [[Apoptosome]]
* [[Bcl-2 homologous antagonist killer]] (BAK)
* [[Bcl-2-associated X protein]] (BAX)
* [[BH3 interacting domain death agonist]] (BID)
* [[Caspases]]
* [[Noxa]]
* [[Microphthalmia-associated transcription factor]]
* [[Protein mimetic]]
* [[p53 upregulated modulator of apoptosis]] (PUMA)
{{colend}}
* [[Senolytics]]

== References ==
{{Reflist|32em}}

== External links ==
* [https://web.archive.org/web/20090221095442/http://bcl2db.ibcp.fr/site/ The Bcl-2 Family Database]
* [http://www.celldeath.de/encyclo/misc/bcl2.htm The Bcl-2 Family at celldeath.de]
* {{MeshName|bcl-2+Genes}}
* {{MeshName|c-bcl-2+Proteins}}
* {{UCSC gene info|BCL2}}
* {{PDBe-KB2|P10415|Human Apoptosis regulator Bcl-2}}

{{Oncogenes}}
{{Fas apoptosis signaling pathway}}

[[Category:Integral membrane proteins]]
[[Category:Peripheral membrane proteins]]
[[Category:Oncogenes]]
[[Category:Apoptosis]]
[[Category:Programmed cell death]]