Novel and Potent Small Molecules against Melanoma Harboring BRAF Class I/II/III Mutants for Overcoming Drug Resistance

Abstract

Melanoma accounts for the majority of skin cancer deaths. About 50% of all melanomas are associated with BRAF mutations. BRAF mutations are classified into three classes with regard to dependency on RAF dimerization and RAS signaling. The most frequently occurring class I BRAF V600 mutations are sensitive to vemurafenib whereas class II and class III mutants, non-V600 BRAF mutants are resistant to vemurafenib. Herein we report six pyrimido[4,5-d]pyrimidin-2-one derivatives possessing highly potent anti-proliferative activities on melanoma cells harboring BRAF class I/II/III mutants. Novel and most potent derivative, SIJ1777, possesses not only two-digit nanomolar potency but also 2 to 14-fold enhanced anti-proliferative activities compared with reference compound, GNF-7 against melanoma cells (SK-MEL-2, SK-MEL-28, A375, WM3670, WM3629). Moreover, SIJ1777 substantially inhibits the activation of MEK, ERK, and AKT and remarkably induces apoptosis and significantly blocks migration, invasion, and anchorage-independent growth of melanoma cells harboring BRAF class I/II/II mutations while both vemurafenib and PLX8394 have little to no effects on melanoma cells expressing BRAF class II/III mutations. Taken together, our six GNF-7 derivatives exhibit highly potent activities against melanoma cells harboring class I/II/III BRAF mutations compared with vemurafenib as well as PLX8394.

Novel Small Molecules Capable of Blocking mtRAS-Signaling Pathway

“…N -(4-Methyl-3-(1-methyl-7-((1-methyl-1 H -pyrazol-3-yl)amino)-2-oxo-1,4-dihydropyrimido[4,5- d ]pyrimidin-3(2 H )-yl)phenyl)-3-(trifluoromethyl)benzamid (11). The synthesis of 11 is described in our previous report ( 29 ).…”

“…Moreover, GNF-7 and its derivatives displayed effect on antileukemic efficacies in blood circulating model (Ba/F3-NRAS-G12D) and xenograft model (OCI-AML3) as well as AKT/ mTOR and GCK signaling, apoptosis, cell cycle arrest, anchorage independent growth in Ba/F3-NRAS-G12D and OCI-AML3 (27). GNF-7 and its derivatives are also reported as pan-class (class I/II/III) BRAF inhibitor in our previous studies, indicating that inhibiting BRAF may be helpful for inhibiting mtRAS signaling pathway (28,29). Overall, our previous findings strongly suggest that the use of multitargeted kinase inhibitor such as GNF-7 can provide an effective approach to discover novel inhibitors targeting mtRAS via blocking its downstream signaling pathway.…”

“…(11). The synthesis of 11 is described in our previous report (29). 27) (100 mg, 0.211 mmol) in 2butanol (2 ml) was added 1-(2-methoxyethyl)-1H-pyrazol-4amine (33 mg, 0.232 mmol), K 2 CO 3 (690 mg, 1.055 mmol), Xphos (20 mg, 0.042 mmol) and Pd 2 (dba) 3 (40 mg, 0.042 mmol) at room temperature.…”

Special Issue “Precision Oncology in Melanoma Progression”

“…The final aim of this review was to highlight the potential synergy between well-studied SM classes and immune-check point inhibitors for the treatment of metastatic melanoma, in order to overcome intrinsic or acquired mechanism of resistance. The experimental work by Kim and colleagues well fits in the context of the development of new small molecules for the treatment of melanoma [ 10 ]. In this paper, a novel GNF-7 (a type-II multi-targeted kinase inhibitor) derivative, SIJ1777, has been shown to have antiproliferative effects toward both class I (i.e., BRAF V600 mutant), sensitive to vemurafenib and class II and class III (non-V600 BRAF mutant), resistant to vemurafenib and PLX8394, melanoma cell lines.…”

“…In this paper, a novel GNF-7 (a type-II multi-targeted kinase inhibitor) derivative, SIJ1777, has been shown to have antiproliferative effects toward both class I (i.e., BRAF V600 mutant), sensitive to vemurafenib and class II and class III (non-V600 BRAF mutant), resistant to vemurafenib and PLX8394, melanoma cell lines. In particular, SIJ1777 inhibited the activation of MEK, ERK and AKT, induced apoptosis and significantly blocked migration, invasion and anchorage-independent growth of melanoma cells harboring BRAF class I/II/II mutations, while both vemurafenib and PLX8394 have little to no effects on melanoma cells expressing BRAF class II/III mutations [ 10 ].…”