Synergistic effect of 5-fluorouracil and the small molecule Wnt/β-catenin inhibitor iCRT3 on Caco-2 colorectal cancer cells in vitro

Although 5-fluorouracil (5-FU) is a cornerstone of colorectal cancer (CRC) treatment, its efficacy is often limited by resistance. Wnt/β-catenin signalling plays a crucial role in CRC carcinogenesis and resistance, as Wnt expression is upregulated in 5-FU-resistant cells, protecting them from cell c...

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Main Authors: Maren Smarslik, Jameel M. Inal
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Heliyon
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Online Access:http://www.sciencedirect.com/science/article/pii/S2405844025010874
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author Maren Smarslik
Jameel M. Inal
author_facet Maren Smarslik
Jameel M. Inal
author_sort Maren Smarslik
collection DOAJ
description Although 5-fluorouracil (5-FU) is a cornerstone of colorectal cancer (CRC) treatment, its efficacy is often limited by resistance. Wnt/β-catenin signalling plays a crucial role in CRC carcinogenesis and resistance, as Wnt expression is upregulated in 5-FU-resistant cells, protecting them from cell cycle arrest and apoptosis, thereby contributing to drug resistance. The small molecule inhibitor β-catenin responsive transcription inhibitor 3 (iCRT3) disrupts Wnt/β-catenin signalling and may enhance CRC sensitivity to 5-FU, overcoming resistance. In this study, the cytotoxic effects of 5-FU and iCRT3 were investigated using the Caco-2 colon adenocarcinoma cell line, marking the first investigation of their combined effects. To this end, the half-maximal inhibitory concentration (IC50) values were determined using the MTT assay. Subsequently, the drugs were combined in different ways, and drug combination index (DCI) calculations were performed to evaluate their interaction. iCRT3 was found to be 2.45-fold more potent than 5-FU (p = 0.1982). Drug combination significantly increased the IC50 compared to 5-FU, with a 40.95-fold increase (p = 0.0022) when 5-FU was fixed (2.56 μM) and a 43.5-fold increase (p = 0.0023) when iCRT3 was fixed (2.41 μM). Two-way ANOVA showed significant impacts from both drug concentration (50.93 %) and treatment condition (25.31 %) on cell viability (p < 0.0001). DCI analysis confirmed strong synergism with fixed 5-FU (DCI = 0.154) and synergism with fixed iCRT3 (DCI = 0.618), indicating that combining 5-FU and iCRT3 could be a promising strategy for CRC treatment, warranting further investigation.
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spelling doaj-art-ca8d97150ca0487a9a16f34b94db33872025-08-20T02:02:24ZengElsevierHeliyon2405-84402025-05-011110e4270610.1016/j.heliyon.2025.e42706Synergistic effect of 5-fluorouracil and the small molecule Wnt/β-catenin inhibitor iCRT3 on Caco-2 colorectal cancer cells in vitroMaren Smarslik0Jameel M. Inal1School of Human Sciences, Cell Communication in Disease Pathology, London Metropolitan University, UK; Corresponding authors. School of Human Sciences, Cell Communication in Disease Pathology, London Metropolitan University, 166-220 Holloway Road, London, N7 8DB, UK.School of Human Sciences, Cell Communication in Disease Pathology, London Metropolitan University, UK; School of Life and Medical Sciences, Biosciences Research Group University of Hertfordshire, UK; Corresponding authors. School of Human Sciences, Cell Communication in Disease Pathology, London Metropolitan University, 166-220 Holloway Road, London, N7 8DB, UK.Although 5-fluorouracil (5-FU) is a cornerstone of colorectal cancer (CRC) treatment, its efficacy is often limited by resistance. Wnt/β-catenin signalling plays a crucial role in CRC carcinogenesis and resistance, as Wnt expression is upregulated in 5-FU-resistant cells, protecting them from cell cycle arrest and apoptosis, thereby contributing to drug resistance. The small molecule inhibitor β-catenin responsive transcription inhibitor 3 (iCRT3) disrupts Wnt/β-catenin signalling and may enhance CRC sensitivity to 5-FU, overcoming resistance. In this study, the cytotoxic effects of 5-FU and iCRT3 were investigated using the Caco-2 colon adenocarcinoma cell line, marking the first investigation of their combined effects. To this end, the half-maximal inhibitory concentration (IC50) values were determined using the MTT assay. Subsequently, the drugs were combined in different ways, and drug combination index (DCI) calculations were performed to evaluate their interaction. iCRT3 was found to be 2.45-fold more potent than 5-FU (p = 0.1982). Drug combination significantly increased the IC50 compared to 5-FU, with a 40.95-fold increase (p = 0.0022) when 5-FU was fixed (2.56 μM) and a 43.5-fold increase (p = 0.0023) when iCRT3 was fixed (2.41 μM). Two-way ANOVA showed significant impacts from both drug concentration (50.93 %) and treatment condition (25.31 %) on cell viability (p < 0.0001). DCI analysis confirmed strong synergism with fixed 5-FU (DCI = 0.154) and synergism with fixed iCRT3 (DCI = 0.618), indicating that combining 5-FU and iCRT3 could be a promising strategy for CRC treatment, warranting further investigation.http://www.sciencedirect.com/science/article/pii/S24058440250108745-FluorouracilColorectal cancerIC50iCRT3Wnt/beta-cateninMTT
spellingShingle Maren Smarslik
Jameel M. Inal
Synergistic effect of 5-fluorouracil and the small molecule Wnt/β-catenin inhibitor iCRT3 on Caco-2 colorectal cancer cells in vitro
Heliyon
5-Fluorouracil
Colorectal cancer
IC50
iCRT3
Wnt/beta-catenin
MTT
title Synergistic effect of 5-fluorouracil and the small molecule Wnt/β-catenin inhibitor iCRT3 on Caco-2 colorectal cancer cells in vitro
title_full Synergistic effect of 5-fluorouracil and the small molecule Wnt/β-catenin inhibitor iCRT3 on Caco-2 colorectal cancer cells in vitro
title_fullStr Synergistic effect of 5-fluorouracil and the small molecule Wnt/β-catenin inhibitor iCRT3 on Caco-2 colorectal cancer cells in vitro
title_full_unstemmed Synergistic effect of 5-fluorouracil and the small molecule Wnt/β-catenin inhibitor iCRT3 on Caco-2 colorectal cancer cells in vitro
title_short Synergistic effect of 5-fluorouracil and the small molecule Wnt/β-catenin inhibitor iCRT3 on Caco-2 colorectal cancer cells in vitro
title_sort synergistic effect of 5 fluorouracil and the small molecule wnt β catenin inhibitor icrt3 on caco 2 colorectal cancer cells in vitro
topic 5-Fluorouracil
Colorectal cancer
IC50
iCRT3
Wnt/beta-catenin
MTT
url http://www.sciencedirect.com/science/article/pii/S2405844025010874
work_keys_str_mv AT marensmarslik synergisticeffectof5fluorouracilandthesmallmoleculewntbcatenininhibitoricrt3oncaco2colorectalcancercellsinvitro
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