Preclinical characterization of tunlametinib, a novel, potent, and selective MEK inhibitor

Background: Aberrant activation of RAS-RAF-MEK-ERK signaling pathway has been implicated in more than one-third of all malignancies. MEK inhibitors are promising therapeutic approaches to target this signaling pathway. Though four MEK inhibitors have been approved by FDA, these compounds possess eit...

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Main Authors: Yahong Liu, Ying Cheng, Gongchao Huang, Xiangying Xia, Xingkai Wang, Hongqi Tian
Format: Article
Language:English
Published: Frontiers Media S.A. 2023-09-01
Series:Frontiers in Pharmacology
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fphar.2023.1271268/full
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author Yahong Liu
Ying Cheng
Gongchao Huang
Xiangying Xia
Xingkai Wang
Hongqi Tian
author_facet Yahong Liu
Ying Cheng
Gongchao Huang
Xiangying Xia
Xingkai Wang
Hongqi Tian
author_sort Yahong Liu
collection DOAJ
description Background: Aberrant activation of RAS-RAF-MEK-ERK signaling pathway has been implicated in more than one-third of all malignancies. MEK inhibitors are promising therapeutic approaches to target this signaling pathway. Though four MEK inhibitors have been approved by FDA, these compounds possess either limited efficacy or unfavorable PK profiles with toxicity issues, hindering their broadly application in clinic. Our efforts were focused on the design and development of a novel MEK inhibitor, which subsequently led to the discovery of tunlametinib.Methods: This study verified the superiority of tunlametinib over the current MEK inhibitors in preclinical studies. The protein kinase selectivity activity of tunlametinib was evaluated against 77 kinases. Anti-proliferation activity was analyzed using the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) or (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assay. ERK and phospho-ERK levels were evaluated by Western blot analysis. Flow cytometry analysis was employed to investigate cell cycle and arrest. Cell-derived xenograft (CDX) and Patient-derived xenograft (PDX) models were used to evaluate the tumor growth inhibition. The efficacy of tunlametinib as monotherapy treatment was evaluated in KRAS/BRAF mutant or wild type xenograft model. Furthermore, the combination studies of tunlametinib with BRAF/KRASG12C/SHP2 inhibitors or chemotherapeutic agent were conducted by using the cell proliferation assay in vitro and xenograft models in vivo.Results:In vitro, tunlametinib demonstrated high selectivity with approximately 19-fold greater potency against MEK kinase than MEK162, and nearly 10–100-fold greater potency against RAS/RAF mutant cell lines than AZD6244. In vivo, tunlametinib resulted in dramatic tumor suppression and profound inhibition of ERK phosphorylation in tumor tissue. Mechanistic study revealed that tunlametinib induced cell cycle arrest at G0/G1 phase and apoptosis of cells in a dose-proportional manner. In addition, tunlametinib demonstrated a favorable pharmacokinetic profile with dose-proportionality and good oral bioavailability, with minimal drug exposure accumulation. Furthermore, tunlametinib combined with BRAF/KRASG12C/SHP2 inhibitors or docetaxel showed synergistically enhanced response and marked tumor inhibition.Conclusion: Tunlametinib exhibited a promising approach for treating RAS/RAF mutant cancers alone or as combination therapies, supporting the evaluation in clinical trials. Currently, the first-in-human phase 1 study and pivotal clinical trial of tunlametinib as monotherapy have been completed and pivotal trials as combination therapy are ongoing.
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spelling doaj.art-b974c78211d44fed8927e24c4cefca762023-09-22T13:25:56ZengFrontiers Media S.A.Frontiers in Pharmacology1663-98122023-09-011410.3389/fphar.2023.12712681271268Preclinical characterization of tunlametinib, a novel, potent, and selective MEK inhibitorYahong LiuYing ChengGongchao HuangXiangying XiaXingkai WangHongqi TianBackground: Aberrant activation of RAS-RAF-MEK-ERK signaling pathway has been implicated in more than one-third of all malignancies. MEK inhibitors are promising therapeutic approaches to target this signaling pathway. Though four MEK inhibitors have been approved by FDA, these compounds possess either limited efficacy or unfavorable PK profiles with toxicity issues, hindering their broadly application in clinic. Our efforts were focused on the design and development of a novel MEK inhibitor, which subsequently led to the discovery of tunlametinib.Methods: This study verified the superiority of tunlametinib over the current MEK inhibitors in preclinical studies. The protein kinase selectivity activity of tunlametinib was evaluated against 77 kinases. Anti-proliferation activity was analyzed using the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) or (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assay. ERK and phospho-ERK levels were evaluated by Western blot analysis. Flow cytometry analysis was employed to investigate cell cycle and arrest. Cell-derived xenograft (CDX) and Patient-derived xenograft (PDX) models were used to evaluate the tumor growth inhibition. The efficacy of tunlametinib as monotherapy treatment was evaluated in KRAS/BRAF mutant or wild type xenograft model. Furthermore, the combination studies of tunlametinib with BRAF/KRASG12C/SHP2 inhibitors or chemotherapeutic agent were conducted by using the cell proliferation assay in vitro and xenograft models in vivo.Results:In vitro, tunlametinib demonstrated high selectivity with approximately 19-fold greater potency against MEK kinase than MEK162, and nearly 10–100-fold greater potency against RAS/RAF mutant cell lines than AZD6244. In vivo, tunlametinib resulted in dramatic tumor suppression and profound inhibition of ERK phosphorylation in tumor tissue. Mechanistic study revealed that tunlametinib induced cell cycle arrest at G0/G1 phase and apoptosis of cells in a dose-proportional manner. In addition, tunlametinib demonstrated a favorable pharmacokinetic profile with dose-proportionality and good oral bioavailability, with minimal drug exposure accumulation. Furthermore, tunlametinib combined with BRAF/KRASG12C/SHP2 inhibitors or docetaxel showed synergistically enhanced response and marked tumor inhibition.Conclusion: Tunlametinib exhibited a promising approach for treating RAS/RAF mutant cancers alone or as combination therapies, supporting the evaluation in clinical trials. Currently, the first-in-human phase 1 study and pivotal clinical trial of tunlametinib as monotherapy have been completed and pivotal trials as combination therapy are ongoing.https://www.frontiersin.org/articles/10.3389/fphar.2023.1271268/fullmek inhibitorRAF/RAS mutant cancertunlametinibdrug combinationhigh potency
spellingShingle Yahong Liu
Ying Cheng
Gongchao Huang
Xiangying Xia
Xingkai Wang
Hongqi Tian
Preclinical characterization of tunlametinib, a novel, potent, and selective MEK inhibitor
Frontiers in Pharmacology
mek inhibitor
RAF/RAS mutant cancer
tunlametinib
drug combination
high potency
title Preclinical characterization of tunlametinib, a novel, potent, and selective MEK inhibitor
title_full Preclinical characterization of tunlametinib, a novel, potent, and selective MEK inhibitor
title_fullStr Preclinical characterization of tunlametinib, a novel, potent, and selective MEK inhibitor
title_full_unstemmed Preclinical characterization of tunlametinib, a novel, potent, and selective MEK inhibitor
title_short Preclinical characterization of tunlametinib, a novel, potent, and selective MEK inhibitor
title_sort preclinical characterization of tunlametinib a novel potent and selective mek inhibitor
topic mek inhibitor
RAF/RAS mutant cancer
tunlametinib
drug combination
high potency
url https://www.frontiersin.org/articles/10.3389/fphar.2023.1271268/full
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