MRK 003

MRK 003 is an orally active γ-secretase inhibitor. MRK 003 targets the Notch signaling pathway by blocking the proteolytic cleavage of Notch receptors. MRK 003 inhibits tumor cell proliferation, induces apoptosis, downregulates anti-apoptotic proteins, upregulates phosphorylated Akt, suppresses angiogenesis, and overcomes microenvironment-mediated proliferative protection. MRK 003 can be used in research related to lung cancer, multiple myeloma, non-Hodgkin's lymphoma, pancreatic ductal adenocarcinoma, glioblastoma, and breast cancer^{[1][2][3][4][5][6][7]}. In Vitro:MRK 003 (0.01-100 μmol/L) inhibits the growth of HCC2429, H460 and A549 non-small cell lung cancer (NSCLC) cell lines in vitro, with IC₅₀ values of 5-10 μmol/L for HCC2429 cells, and approximately 25 μmol/L for H460 and A549 cells^[1].
MRK 003 inhibits the canonical Notch signaling pathway in HCC2429 non-small cell lung cancer cells, reducing the transcriptional levels of HES1 and Hey1 by 4-fold and 2-fold, respectively, and increasing the transcriptional level of hASH1 by 4-fold^[1].
MRK 003 (pre-incubated for 24 h prior to serum stimulation at concentrations of 5-10 μmol/L) reduces serum-induced pERK activation in HCC2429 non-small cell lung cancer cells, with a significant reduction observed after 30 minutes of stimulation with 10% FCS^[1].
MRK 003 (10 μmol/L) reduces soft agar colony formation in HCC2429 non-small cell lung cancer cells, and this effect is significantly enhanced when combined with the EGFR tyrosine kinase inhibitor AG1478 (HY-13524)^[1].
MRK 003 (5-30 μM; 48 h) induces dose-dependent cytotoxicity in human multiple myeloma (MM1.S, MM1.R, RPMI 8226, DOX 40, LR5, U266, OPM-2, NCI-H929) and non-Hodgkin's lymphoma (Ramos, Dohh2, Karpas 422) cell lines, with IC₅₀ values of 15-30 μM and 15-25 μM, respectively, whereas the Granta 519 non-Hodgkin's lymphoma cell line exhibits drug resistance^[4].
MRK 003 (5-35 μM; 48 h) inhibits the proliferation of human multiple myeloma (MM1.S, MM1.R, RPMI 8226, DOX 40, LR5, U266, NCI-H929) and non-Hodgkin's lymphoma (Ramos, Dohh2, Karpas 422, Granta 519) cell lines, among which MM1.S, MM1.R, H929 and U266 cells exhibit higher sensitivity at lower concentrations^[4].
MRK 003 (5-30 μM; 48 h) reverses the pro-proliferative effect of patient-derived bone marrow mesenchymal stem cells (BMSCs), thereby inhibiting the proliferation of human MM1.S multiple myeloma cells after 48 h of incubation^[4].
MRK 003 (5-30 μM; 48 h) inhibits cytokine-induced proliferation of human MM1.S multiple myeloma (MM) cells and Dohh2 non-Hodgkin's lymphoma (NHL) cells following 48 h of incubation^[4].
MRK 003 (20 μM; 12, 24 h) regulates the Notch, PI3K/Akt, Ras/Mek/Erk, NF-κB pathways as well as anti-apoptotic pathways in a cell type-specific manner in human RPMI 8226 multiple myeloma (MM) cells and Dohh2 non-Hodgkin's lymphoma (NHL) cells, with incubation durations of 12 h and 24 h^[4].
MRK 003 (0.01-10 μmol/L; 1 week) irreversibly reduces the sphere-forming cell frequency of primary mouse ERBB2 transgenic breast cancer cells and established mouse tumor spheres, while reversibly decreasing the sphere-forming cell frequency of primary mouse mammary epithelial cells and established mouse mammospheres, with complete inhibition achieved at a concentration of 10 μmol/L^[5].
MRK 003 (0.1-10 μmol/L) promotes the differentiation of primary mouse mammary epithelial bipotent progenitor cells and primary mouse ERBB2-transgenic mammary tumor-like progenitor cells toward the myoepithelial lineage, without altering the frequency of overall colony-forming cells^[5].
MRK 003 (2-5 μmol/L; 48 h) reduces the proportion of CD44⁺CD24⁺ and ALDH⁺ tumor-initiating cell populations in sensitive pancreatic ductal adenocarcinoma (PDAC) cell lines (Capan-1, Pa03C), while increasing the proportion of these cell populations in drug-resistant cell lines (Pa16C, Pa29C)^[6].
MRK 003 (2-5 μmol/L; 48 h) downregulates the mRNA expression of Hes-1 in Capan-1, Pa03C, Pa14C, Pa16C and Pa29C pancreatic ductal adenocarcinoma (PDAC) cell lines^[6].
MRK 003 (2-5 μmol/L; 48 h pre-incubation) inhibits the anchorage-independent growth of sensitive pancreatic ductal adenocarcinoma (PDAC) cell lines (Capan-1, Pa03C, Pa14C); stable overexpression of N1ICD in Pa03C cells reverses this effect, while drug-resistant cell lines (Pa16C, Pa29C) show no response to any of the above concentrations^[6].
MRK 003 (1-10 μmol/L; 96 h) potently inhibits the proliferation of HSR-GBM1 and 040821 glioblastoma neurospheres in vitro, including vehicle-treated intracranial xenograft-derived neurospheres, with maximal growth inhibition observed at concentrations ≥4 μmol/L^[7].
MRK 003 (5-10 μmol/L) induces apoptosis in HCC2429 non-small cell lung cancer cells by downregulating the pro-survival proteins pBcl-2 and Bcl-xL, activating the caspase pathway (evidenced by cleaved PARP), and increasing cytochrome c levels, with no effect on the expression of Bax or pAkt^[1].
MRK 003 (under serum starvation for 48 h) significantly enhances apoptosis of HCC2429, H1793 and A549 non-small cell lung cancer (NSCLC) cells under serum starvation conditions, but exerts no effect on apoptosis of cells cultured in 10% FCS^[1].
The pro-apoptotic potency of MRK 003 (24 h, 48 h) decreases in transient Notch3-knockdown HCC2429 non-small cell lung cancer cells, which further confirms that the pro-apoptotic activity of MRK-003 depends on Notch3^[1].
MRK 003 (20 μM; 6-48 h) induces time-dependent apoptosis in human MM1.S, RPMI 8226 multiple myeloma (MM) cells and Dohh2 non-Hodgkin's lymphoma (NHL) cells, with the survival rates of these cells decreasing to 43%, 3.3% and 36% respectively after 48 h^[4].
MRK 003 (20 μM; 48 h) induces activation of caspase-3, -8, and -9, and mediates caspase-dependent apoptosis in human MM1.S multiple myeloma (MM) cells and Dohh2 non-Hodgkin's lymphoma (NHL) cells^[4].
MRK 003 (1 nM-10 μM) inhibits in vitro angiogenesis of co-cultured human endothelial cells, fibroblasts and myoblasts at a concentration of 10 μM, which is lower than its cytotoxic IC₅₀ against MM and NHL cells^[4]. In Vivo:MRK-003 (100 mg/kg; 3 days per week) inhibits Notch3 activation and induces statistically significant tumor volume reduction in HCC2429 and H460 human lung cancer xenograft models, with marked tumor necrosis observed in HCC2429 tumors^[1].
MRK 003 (5 μmol/L; 48 hours) significantly delays tumor xenograft growth of MRK-003-sensitive PDAC cell lines (Capan-1, Pa03C) in athymic nude mice, but exerts no effect on drug-resistant cell lines (Pa16C, Pa29C)^[6].
MRK 003 (300 mg/kg; p.o.; once weekly; for 5 consecutive weeks) slows tumor growth by 49% and 62% in HSR-GBM1 and 040821 human glioblastoma neurosphere intracranial xenograft models, respectively, and extends the median survival from 29 days to 35 days and from 28 days to 40 days, respectively. In addition, MRK-003 reduces Hes1, Hes5, Hey1 and neural stem/progenitor cell markers, decreases mitosis and clonogenic capacity, and promotes glial differentiation^[7].
Combination treatment with MRK 003 (100 mg/kg; p.o.; administered for 3 days followed by a 4-day drug holiday) and Trastuzumab (HY-P9907) completely prevents tumor recurrence (0% recurrence rate at 40 weeks) in Trastuzumab-sensitive ErbB-2-positive breast cancer xenograft models, by inducing apoptosis, inhibiting proliferation, and almost completely blocking the ERK1/2 and AKT1 signaling pathways^[3].
Combination treatment with MRK 003 (100 mg/kg; p.o.; administered for 3 days followed by a 4-day withdrawal) and Lapatinib (HY-50898) significantly reduces tumor growth of Lapatinib-sensitive ErbB-2-positive breast cancer xenografts by inducing apoptosis, inhibiting proliferation, and blocking the ERK1/2 and AKT1 signaling pathways^[3].
MRK-003 (150 mg/kg; p.o.; administered consecutively for 3 days followed by a 4-day drug holiday, repeated once) induces rapid and durable regression of breast tumors in mice by inhibiting tumor cell proliferation, inducing apoptosis, promoting differentiation, and eliminating tumor-initiating cells, resulting in 100% relapse-free survival for up to 1 year in treated mice^[5].
MRK 003 (75-450 mg/kg; p.o.; once weekly; 3 cycles) inhibits the Notch signaling pathway and reduces the proliferation of tumor cells in BH breast cancer xenografts. Its growth inhibitory effect is dose-dependent, and the sensitivity varies among different tumor cell lines; at a dose of 300 mg/kg administered weekly, the proportion of Ki67-positive cells decreases by approximately 75%^[2].