Details of the Drug Combination

General Information of Drug Combination (ID: DCRF0IM)

• Drug Combination Name: Letrozole + BIBW 2992
• Indication: Breast Neoplasms; Status: Phase 2 [1]
• Component Drugs:
  Letrozole (DMH07Y3): Small molecular drug
  BIBW 2992 (DMTKD7Q): Small molecular drug

Molecular Interaction Atlas of This Drug Combination

Indication(s) of Letrozole

Disease Entry	ICD 11	Status	REF
Estrogen-receptor positive breast cancer	N.A.	Approved	[2]
Hormonally-responsive breast cancer	2C60-2C65	Approved	[3]

Letrozole Interacts with 1 DTT Molecule(s)

DTT Name	DTT ID	UniProt ID	Mode of Action	REF
Aromatase (CYP19A1)	TTSZLWK	CP19A_HUMAN	Inhibitor	[5]

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	[6]
Aromatase (CYP19A1)	DEQX145	CP19A_HUMAN	Metabolism	[7]
Cytochrome P450 2A6 (CYP2A6)	DEJVYAZ	CP2A6_HUMAN	Metabolism	[8]

Letrozole Interacts with 18 DOT Molecule(s)

DOT Name	DOT ID	UniProt ID	Mode of Action	REF
Aromatase (CYP19A1)	OTZ6XF74	CP19A_HUMAN	Decreases Activity	[9]
Cytochrome P450 3A4 (CYP3A4)	OTQGYY83	CP3A4_HUMAN	Increases Oxidation	[10]
Cytochrome P450 2A6 (CYP2A6)	OT52TWG3	CP2A6_HUMAN	Increases Oxidation	[10]
Adenylate kinase isoenzyme 1 (AK1)	OT614AR3	KAD1_HUMAN	Increases ADR	[11]
Dickkopf-related protein 1 (DKK1)	OTRDLUSP	DKK1_HUMAN	Increases Expression	[12]
Follitropin subunit beta (FSHB)	OTGLS283	FSHB_HUMAN	Increases Expression	[13]
Lutropin subunit beta (LHB)	OT5GBOVJ	LSHB_HUMAN	Increases Expression	[13]
Progesterone receptor (PGR)	OT0FZ3QE	PRGR_HUMAN	Decreases Expression	[14]
Leukemia inhibitory factor (LIF)	OTO46S5S	LIF_HUMAN	Increases Expression	[12]
Gap junction alpha-1 protein (GJA1)	OTT94MKL	CXA1_HUMAN	Decreases Expression	[15]
G1/S-specific cyclin-D1 (CCND1)	OT8HPTKJ	CCND1_HUMAN	Decreases Expression	[16]
G1/S-specific cyclin-D2 (CCND2)	OTDULQF9	CCND2_HUMAN	Decreases Expression	[16]
Cyclin-dependent kinase inhibitor 1 (CDKN1A)	OTQWHCZE	CDN1A_HUMAN	Increases Expression	[17]
Leukemia inhibitory factor receptor (LIFR)	OT36W9O5	LIFR_HUMAN	Increases Expression	[12]
Proliferation marker protein Ki-67 (MKI67)	OTA8N1QI	KI67_HUMAN	Decreases Expression	[14]
Small ribosomal subunit protein eS6 (RPS6)	OTT4D1LN	RS6_HUMAN	Decreases Phosphorylation	[16]
Lanosterol 14-alpha demethylase (CYP51A1)	OTAYHG9C	CP51A_HUMAN	Decreases Activity	[18]
Fibroblast growth factor 22 (FGF22)	OTVIX6J0	FGF22_HUMAN	Increases Expression	[12]

Indication(s) of BIBW 2992

Disease Entry	ICD 11	Status	REF
Non-small-cell lung cancer	2C25.Y	Approved	[4]

BIBW 2992 Interacts with 2 DTT Molecule(s)

DTT Name	DTT ID	UniProt ID	Mode of Action	REF
Erbb2 tyrosine kinase receptor (HER2)	TT6EO5L	ERBB2_HUMAN	Inhibitor	[19]
Epidermal growth factor receptor (EGFR)	TTGKNB4	EGFR_HUMAN	Inhibitor	[19]

BIBW 2992 Interacts with 2 DTP Molecule(s)

DTP Name	DTP ID	UniProt ID	Mode of Action	REF
P-glycoprotein 1 (ABCB1)	DTUGYRD	MDR1_HUMAN	Substrate	[20]
Breast cancer resistance protein (ABCG2)	DTI7UX6	ABCG2_HUMAN	Substrate	[20]

BIBW 2992 Interacts with 6 DOT Molecule(s)

DOT Name	DOT ID	UniProt ID	Mode of Action	REF
Epidermal growth factor receptor (EGFR)	OTAPLO1S	EGFR_HUMAN	Decreases Activity	[21]
Inhibitor of nuclear factor kappa-B kinase subunit beta (IKBKB)	OT9RDS3H	IKKB_HUMAN	Decreases Expression	[22]
Ras GTPase-activating-like protein IQGAP1 (IQGAP1)	OTZRWTGA	IQGA1_HUMAN	Decreases Phosphorylation	[23]
Protein SET (SET)	OTGYYQJO	SET_HUMAN	Affects Localization	[24]
POU domain, class 5, transcription factor 1 (POU5F1)	OTDHHN7O	PO5F1_HUMAN	Decreases Expression	[25]
Calmodulin-1 (CALM2)	OTNYA92F	CALM1_HUMAN	Affects Response To Substance	[26]

References

• [1] ClinicalTrials.gov (NCT02115048) Clinical Study for the Treatment of Breast Cancer: the Patient Will Receive Afatinib Plus Letrozole or Letrozole Alone
• [2] Letrozole FDA Label
• [3] 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).
• [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: 5667).
• [5] Aromatase inhibitors--theoretical concept and present experiences in the treatment of endometriosis. Zentralbl Gynakol. 2003 Jul-Aug;125(7-8):247-51.
• [6] 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.
• [7] Double-blind, randomised, multicentre endocrine trial comparing two letrozole doses, in postmenopausal breast cancer patients. Eur J Cancer. 1999 Feb;35(2):208-13.
• [8] 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.
• [9] Aromatase inhibition: translation into a successful therapeutic approach. Clin Cancer Res. 2005 Apr 15;11(8):2809-21. doi: 10.1158/1078-0432.CCR-04-2187.
• [10] Deactivation of anti-cancer drug letrozole to a carbinol metabolite by polymorphic cytochrome P450 2A6 in human liver microsomes. Xenobiotica. 2009 Nov;39(11):795-802. doi: 10.3109/00498250903171395.
• [11] 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.
• [12] 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.
• [13] Aromatase inhibition, testosterone, and seizures. Epilepsy Behav. 2004 Apr;5(2):260-3. doi: 10.1016/j.yebeh.2003.12.001.
• [14] Aromatase inhibitors: cellular and molecular effects. J Steroid Biochem Mol Biol. 2005 May;95(1-5):83-9. doi: 10.1016/j.jsbmb.2005.04.010.
• [15] Inhibition of estrogen receptor reduces connexin 43 expression in breast cancers. Toxicol Appl Pharmacol. 2018 Jan 1;338:182-190. doi: 10.1016/j.taap.2017.11.020. Epub 2017 Nov 24.
• [16] 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.
• [17] 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.
• [18] Comparison of lanosterol-14 alpha-demethylase (CYP51) of human and Candida albicans for inhibition by different antifungal azoles. Toxicology. 2006 Nov 10;228(1):24-32. doi: 10.1016/j.tox.2006.08.007. Epub 2006 Aug 12.
• [19] Boehringer Ingelheim. Product Development Pipeline. June 2 2009.
• [20] Breast cancer resistance protein (BCRP/ABCG2) and P-glycoprotein (P-gp/ABCB1) transport afatinib and restrict its oral availability and brain accumulation. Pharmacol Res. 2017 Jun;120:43-50.
• [21] Cysteine mapping in conformationally distinct kinase nucleotide binding sites: application to the design of selective covalent inhibitors. J Med Chem. 2011 Mar 10;54(5):1347-55. doi: 10.1021/jm101396q. Epub 2011 Feb 15.
• [22] Irreversible EGFR inhibitor EKB-569 targets low-LET -radiation-triggered rel orchestration and potentiates cell death in squamous cell carcinoma. PLoS One. 2011;6(12):e29705. doi: 10.1371/journal.pone.0029705. Epub 2011 Dec 29.
• [23] Tyrosine phosphorylation of the scaffold protein IQGAP1 in the MET pathway alters function. J Biol Chem. 2020 Dec 25;295(52):18105-18121. doi: 10.1074/jbc.RA120.015891. Epub 2020 Oct 21.
• [24] Oncoprotein SET dynamically regulates cellular stress response through nucleocytoplasmic transport in breast cancer. Cell Biol Toxicol. 2023 Aug;39(4):1795-1814. doi: 10.1007/s10565-022-09784-4. Epub 2022 Dec 19.
• [25] YM155 as an inhibitor of cancer stemness simultaneously inhibits autophosphorylation of epidermal growth factor receptor and G9a-mediated stemness in lung cancer cells. PLoS One. 2017 Aug 7;12(8):e0182149. doi: 10.1371/journal.pone.0182149. eCollection 2017.
• [26] Knockdown of CALM2 increases the sensitivity to afatinib in HER2-amplified gastric cancer cells by regulating the Akt/FoxO3a/Puma axis. Toxicol In Vitro. 2023 Mar;87:105531. doi: 10.1016/j.tiv.2022.105531. Epub 2022 Nov 29.