Notch signalling pathway in development of cholangiocarcinoma

Table 2 Anti-Notch therapeutic targets examined in vivo and/or in vitro for the treatment of cholangiocarcinoma

Molecules/Targets and Functions	Experiments	Results and findings
GSI IX (Gamma Secretase Inhibitor)	In resected specimens of EH-CCA	In all of CC cell lines, treatment of GSI IX considerably reduces the subpopulation of CD24+ +CD44++ cells (Cancer Stem Cells, CScs)[60]
RO4929097 (Gamma Secretase Inhibitor)	Pancreatic adenocarcinoma patients	25% treated patients attained the stable disease, while the 6-month survival rate was found to be 27.8%. Additionally, decrease in the expression of HeyL was observed following the drug administration[82]
DAPT (Gamma Secretase Inhibitor)	Cell lines (SZ1, MzChA1, EgI1 and TFK1)	Cause the decrease of the expression of the cleaved form of the Notch receptor and Hes1, with the subsequent overexpression of the cyclin kinase inhibitors (p21, p27 and p53)[30]
FLI-06 (Gamma Secretase Inhibitor)	IH-CCA cells	Found to be completely diminished the MFAP5- dependent Notch activation in CCA[84]
Brontictuzumab, OMP-52M51 (Anti-Notch1 antibody)	Phase 1 Clinical Trial	The treatment study was done on 07 CCA patients. It showed single-agent efficacy. While patients had a partial response, specifically in the NICD high population[87]
Tarextumab, OMP-59R5 (Anti-Notch2/3 antibody)	Phase 2 Clinical Trial	Phase1b/2 study conducted on SCLC (Small Cell Lung Cancer) and pancreatic cancer. Phase1b results showed a greater tumor reduction at high dose of TRXT[87]
Demcizumab, OMP- 21M18 [Anti-Delta-like ligand 4 (Dll4)]	Phase1/2 clinical trial	In NSCLC (Non-Squamous Non-small Cell Lung Cancer) patients treated with Demcizumab, 3% of patients had a valuable response, 48% had a partial response and 38% showed a stable disease. In pancreatic cancer patients, 50% of valuable patients who received Demcizumab showed a partial response[88,89]
RNA interfering antisense oligonucleotide (AS-ODN, a specific Notch2 Inhibitor)	B-CLL cells	AS-ODNs results in down-regulation of Notch 2 activity in pathogenicity of B-CLL[91]
miR-34a (Anti-tumorgenic effect)	Human CCA cells (CCLP1, TFK1, SG231 and HUCCT1)	miR-34a expression is silenced epigenetically by EZH2 that tends to result in progression of CCA cell growth via Notch cascade activation, so it’s activation via inhibition of EZH2 inhibitor results in the significant decrease of tumor burden[94]
Niclosamide (An antheliminthic drug)	Colon cancer cell lines (HCT116, LoVo and SW620 cells)	Niclosamide results in inhibition of the progression of colon cancer by up-regulating the miR-200 family members and by down-regulating the Notch signaling pathway[95]
Hydrocarbon-stapled α-helical peptide (SAHM1)	T-cell acute lymphoblastic leukaemia	It prevents the formation of Notch trans-activation complex and subsequently suppresses the development of in vivo and in vitro T- Cell acute leukemia[96]
Inhibitor of mastermind Recruitment-1 (IMR-1)	Notch-dependent cell lines and patient-derived tumor xenografts	It disrupts the recruitment of Mastermind-like to the Notch transcriptional activation complex and, thus attenuates the Notch target gene transcription[97]
MO-I-1100 (SMI, Small Molecule inhibitor of β-hydroxylase)	FOCUS, HCC cell line, BNLT3, Huh7, Hep3B and HepG2	It reduces the ASPH enzymatic activity and inhibits the proliferation, invasion and growth of HCC cell lines and animal models. The mechanism of effect is based on the antitumor effect with the reduced activation of Notch Signalling cascade, both in vivo and in vitro[98]
MO-I-1151 (Second Generation Small Molecule Inhibitor, SMI of β-hydroxylase)	Human CCA cell lines (ETK1, RBE, SSP25 and BDE-Neu CL24 cells)	It exhibits the inhibition on CCA cell migration and proliferation and also significantly suppresses tumor growth and progression of CCA. The treatment also results in suppression of overexpression of Notch1 and Hey1 in the tumors[99]
Corilagin (A natural plant derivative, Polyphenol Tannic Acid)	Human CCA cell lines (MZ-Cha-1 and QBC9939)	It inhibits the CCA cell proliferation and invasion and increases the CCA cell apoptosis. It inhibits the AKT phosphorylation and counteracts the AKT phosphorylation that is induced by NICD1 and consequently inhibits the Notch1 and Hes1 mRNA expression[100]
Curcumin (A phytochemical derived from turmeric, Curcuma longa)	Human IH-CCA cell lines (SG-231 and CCLP-1)	It reduces the viability and colony-forming ability of CCA cells. Even at low concentration, it effectively reduces the growth of the cells and stimulates the apoptosis with subsequent suppression of Notch1 and Hes1 mRNA expression[101]
Cinobufagin (Chansu, Toad Venom)	Human prostate carcinoma cell lines (DU145, LNCaP and PC3 cells), Normal breast epithelial cell lines, Human CCA cell lines RBE (IH-CCA) and QBC939 (EX-CCA)	Cinobufagin causes and cell apoptosis and anti-proliferative effects in cancer cells[103]. Cinobufagin-derived inactivation of Notch signalling pathway results in the stimulation of apoptosis in CCA cells[104]
Xanthohumol (A Prenylated Chalcone)	SG-231and CCLP-1 derived mouse xenografts	Xanthohumol causes the cell cycle arrest via an increase in pro-apoptotic markers and induces the apoptosis. It also results in reduction of AKT and Notch1 expression level in a time dependent fashion[105]

CCA: Cholangiocarcinoma; IH-CCA: Intrahepatic cholangiocarcinoma; NICD: Notch intracellular domain; IMR-1: Inhibitor of Mastermind Recruitment-1; SMI: Small-molecule inhibitor; GSI: Gamma-secretase inhibitors.