Details of the Drug Combination

General Information of Drug Combination (ID: DCOT3OH)

• Drug Combination Name: Thioguanine + Letrozole
• Indication: Adenocarcinoma; Status: Investigative [1]
• Component Drugs:
  Thioguanine (DM7NKEV): Small molecular drug
  Letrozole (DMH07Y3): Small molecular drug
• High-throughput Screening Result:
  Testing Cell Line: NCIH23
  Zero Interaction Potency (ZIP) Score: 1.49
  Bliss Independence Score: 3.56
  Loewe Additivity Score: 1.04
  LHighest Single Agent (HSA) Score: 3.75

Molecular Interaction Atlas of This Drug Combination

Indication(s) of Thioguanine

Disease Entry	ICD 11	Status	REF
Acute lymphocytic leukaemia	2B33.3	Approved	[2]
Acute myelogenous leukaemia	2A41	Approved	[3]
Acute myeloid leukaemia	2A60	Approved	[4]
Middle East Respiratory Syndrome (MERS)	1D64	Preclinical	[5]
Severe acute respiratory syndrome (SARS)	1D65	Preclinical	[5]

Thioguanine Interacts with 3 DTT Molecule(s)

DTT Name	DTT ID	UniProt ID	Mode of Action	REF
MERS-CoV papain-like proteinase (PL-PRO)	TTYJOLE	R1AB_CVEMC (854-2740)	Inhibitor	[5]
Inosine-5'-monophosphate dehydrogenase (IMPDH)	TTCAQMW	NOUNIPROTAC	Intercalator	[8]
SARS-CoV papain-like proteinase (PL-PRO)	TTRGHB2	R1AB_CVHSA (819-2740)	Inhibitor	[5]

Thioguanine Interacts with 3 DTP Molecule(s)

DTP Name	DTP ID	UniProt ID	Mode of Action	REF
Breast cancer resistance protein (ABCG2)	DTI7UX6	ABCG2_HUMAN	Substrate	[9]
Multidrug resistance-associated protein 4 (ABCC4)	DTCSGPB	MRP4_HUMAN	Substrate	[10]
Concentrative Na(+)-nucleoside cotransporter 3 (SLC28A3)	DT4YL5R	S28A3_HUMAN	Substrate	[11]

Thioguanine Interacts with 2 DME Molecule(s)

DME Name	DME ID	UniProt ID	Mode of Action	REF
Thiopurine methyltransferase (TPMT)	DEFQ8VO	TPMT_HUMAN	Metabolism	[12]
Hypoxanthine phosphoribosyltransferase (HPRT1)	DEVXTP5	HPRT_HUMAN	Metabolism	[13]

Thioguanine Interacts with 3 DOT Molecule(s)

DOT Name	DOT ID	UniProt ID	Mode of Action	REF
Occludin (OCLN)	OTSUTVWL	OCLN_HUMAN	Decreases Activity	[14]
ATP-binding cassette sub-family C member 5 (ABCC5)	OT34G4US	MRP5_HUMAN	Decreases Response To Substance	[15]
Baculoviral IAP repeat-containing protein 2 (BIRC2)	OTFXFREP	BIRC2_HUMAN	Decreases Response To Substance	[16]

Indication(s) of Letrozole

Disease Entry	ICD 11	Status	REF
Estrogen-receptor positive breast cancer	N.A.	Approved	[6]
Hormonally-responsive breast cancer	2C60-2C65	Approved	[7]

Letrozole Interacts with 1 DTT Molecule(s)

DTT Name	DTT ID	UniProt ID	Mode of Action	REF
Aromatase (CYP19A1)	TTSZLWK	CP19A_HUMAN	Inhibitor	[17]

Letrozole Interacts with 3 DME Molecule(s)

DME Name	DME ID	UniProt ID	Mode of Action	REF
Cytochrome P450 3A4 (CYP3A4)	DE4LYSA	CP3A4_HUMAN	Metabolism	[18]
Aromatase (CYP19A1)	DEQX145	CP19A_HUMAN	Metabolism	[19]
Cytochrome P450 2A6 (CYP2A6)	DEJVYAZ	CP2A6_HUMAN	Metabolism	[20]

Letrozole Interacts with 7 DOT Molecule(s)

DOT Name	DOT ID	UniProt ID	Mode of Action	REF
Adenylate kinase isoenzyme 1 (AK1)	OT614AR3	KAD1_HUMAN	Increases ADR	[21]
Follitropin subunit beta (FSHB)	OTGLS283	FSHB_HUMAN	Increases Expression	[22]
Lutropin subunit beta (LHB)	OT5GBOVJ	LSHB_HUMAN	Increases Expression	[22]
G1/S-specific cyclin-D2 (CCND2)	OTDULQF9	CCND2_HUMAN	Decreases Expression	[23]
Cyclin-dependent kinase inhibitor 1 (CDKN1A)	OTQWHCZE	CDN1A_HUMAN	Increases Expression	[24]
Small ribosomal subunit protein eS6 (RPS6)	OTT4D1LN	RS6_HUMAN	Decreases Phosphorylation	[23]
Fibroblast growth factor 22 (FGF22)	OTVIX6J0	FGF22_HUMAN	Increases Expression	[25]

Test Results of This Drug Combination in Other Disease Systems

Indication	DrugCom ID	Cell Line	Status	REF
Plasma cell myeloma	DC0ABS5	RPMI-8226	Investigative	[26]
Invasive ductal carcinoma	DCOCZU8	HS 578T	Investigative	[27]
Adenocarcinoma	DCT9XYE	SW-620	Investigative	[1]
Adenocarcinoma	DCCL7S4	HCT-15	Investigative	[1]
Adenocarcinoma	DC8R2SI	HCT116	Investigative	[1]
Prostate carcinoma	DC1VLTX	PC-3	Investigative	[1]

References

• [1] CheMBL Affinity Phenotypic Cellular Interaction Assay ID: CHEMBL1125976
• [2] Drugs@FDA. U.S. Food and Drug Administration. U.S. Department of Health & Human Services. 2015
• [3] Thioguanine FDA Label
• [4] URL: http://www.guidetopharmacology.org Nucleic Acids Res. 2015 Oct 12. pii: gkv1037. The IUPHAR/BPS Guide to PHARMACOLOGY in 2016: towards curated quantitative interactions between 1300 protein targets and 6000 ligands. (Ligand id: 6845).
• [5] Thiopurine analogs and mycophenolic acid synergistically inhibit the papain-like protease of Middle East respiratory syndrome coronavirus. Antiviral Res. 2015 Mar;115:9-16.
• [6] Letrozole FDA Label
• [7] URL: http://www.guidetopharmacology.org Nucleic Acids Res. 2015 Oct 12. pii: gkv1037. The IUPHAR/BPS Guide to PHARMACOLOGY in 2016: towards curated quantitative interactions between 1300 protein targets and 6000 ligands. (Ligand id: 5209).
• [8] Immune effector cells produce lethal DNA damage in cells treated with a thiopurine. Cancer Res. 2009 Mar 15;69(6):2393-9.
• [9] ABC transporters and their role in nucleoside and nucleotide drug resistance. Biochem Pharmacol. 2012 Apr 15;83(8):1073-83.
• [10] Multidrug resistance protein 4 (MRP4/ABCC4) mediates efflux of bimane-glutathione. Int J Biochem Cell Biol. 2004 Feb;36(2):247-57.
• [11] Involvement of the concentrative nucleoside transporter 3 and equilibrative nucleoside transporter 2 in the resistance of T-lymphoblastic cell lines to thiopurines. Biochem Biophys Res Commun. 2006 Apr 28;343(1):208-15.
• [12] Usefulness of thiopurine methyltransferase and thiopurine metabolite analysis in clinical practice in patients with inflammatory bowel diseases. Acta Gastroenterol Belg. 2010 Jul-Sep;73(3):331-5.
• [13] Qualitative and quantitative difference in mutation induction between carbon- and neon-ion beams in normal human cells. Biol Sci Space. 2003 Dec;17(4):302-6.
• [14] The thiopurine methyltransferase genetic polymorphism is associated with thioguanine-related veno-occlusive disease of the liver in children with acute lymphoblastic leukemia. Clin Pharmacol Ther. 2006 Oct;80(4):375-83. doi: 10.1016/j.clpt.2006.07.002.
• [15] The multidrug resistance protein 5 (ABCC5) confers resistance to 5-fluorouracil and transports its monophosphorylated metabolites. Mol Cancer Ther. 2005 May;4(5):855-63.
• [16] Expression and prognostic significance of IAP-family genes in human cancers and myeloid leukemias. Clin Cancer Res. 2000 May;6(5):1796-803.
• [17] Aromatase inhibitors--theoretical concept and present experiences in the treatment of endometriosis. Zentralbl Gynakol. 2003 Jul-Aug;125(7-8):247-51.
• [18] Inhibition of drug metabolizing cytochrome P450s by the aromatase inhibitor drug letrozole and its major oxidative metabolite 4,4'-methanol-bisbenzonitrile in vitro. Cancer Chemother Pharmacol. 2009 Oct;64(5):867-75.
• [19] Double-blind, randomised, multicentre endocrine trial comparing two letrozole doses, in postmenopausal breast cancer patients. Eur J Cancer. 1999 Feb;35(2):208-13.
• [20] Letrozole concentration is associated with CYP2A6 variation but not with arthralgia in patients with breast cancer. Breast Cancer Res Treat. 2018 Nov;172(2):371-379.
• [21] ADReCS-Target: target profiles for aiding drug safety research and application. Nucleic Acids Res. 2018 Jan 4;46(D1):D911-D917. doi: 10.1093/nar/gkx899.
• [22] Aromatase inhibition, testosterone, and seizures. Epilepsy Behav. 2004 Apr;5(2):260-3. doi: 10.1016/j.yebeh.2003.12.001.
• [23] Dual inhibition of mTOR and estrogen receptor signaling in vitro induces cell death in models of breast cancer. Clin Cancer Res. 2005 Jul 15;11(14):5319-28. doi: 10.1158/1078-0432.CCR-04-2402.
• [24] Synergistic activity of letrozole and sorafenib on breast cancer cells. Breast Cancer Res Treat. 2010 Nov;124(1):79-88. doi: 10.1007/s10549-009-0714-5. Epub 2010 Jan 7.
• [25] Clomiphene citrate versus letrozole: molecular analysis of the endometrium in women with polycystic ovary syndrome. Fertil Steril. 2011 Oct;96(4):1051-6. doi: 10.1016/j.fertnstert.2011.07.1092.
• [26] CheMBL Affinity Phenotypic Cellular Interaction Assay ID: CHEMBL1125966
• [27] CheMBL Affinity Phenotypic Cellular Interaction Assay ID: CHEMBL1126165