Reversing chemorefraction in colorectal cancer cells by controlling mucin secretion
- Vall d'Hebron Institut de Recerca, Spain
- Institut Mar d'Investigacions Mèdiques, Spain
- The Barcelona Institute of Science and Technology, Spain
Abstract
15% of colorectal cancers (CRC) cells exhibit a mucin hypersecretory phenotype, which is suggested to provide resistance to immune surveillance and chemotherapy. We now formally show that colorectal cancer cells build a barrier to chemotherapeutics by increasing mucins' secretion. We show that low levels of KChIP3, a negative regulator of mucin secretion (Cantero-Recasens et al., 2018), is a risk factor for CRC patients' relapse in subset of untreated tumours. Our results also reveal that cells depleted of KChIP3 are four times more resistant (measured as cell viability and DNA damage) to chemotherapeutics 5-Fluorouracil plus Irinotecan (5-FU+iri.) compared to control cells, whereas KChIP3 overexpressing cells are 10 times more sensitive to killing by chemotherapeutics. Similar increase in tumour cell death is observed upon chemical inhibition of mucin secretion by the sodium/calcium exchanger (NCX) blockers (Mitrovic et al., 2013). Finally, sensitivity of CRC patient-derived organoids to 5-FU+iri increases 40-fold upon mucin secretion inhibition. Reducing mucin secretion thus provides a means to control chemoresistance of mucinous colorectal cancer cells and other mucinous tumours.
Data availability
All data generated or analysed are included in the manuscript
Article and author information
Author details
Gerard Cantero-Recasens
Funding
Ministerio de Economía, Industria y Competitividad, Gobierno de España (BFU2013-44188-P)
- Vivek Malhotra
Instituto de Salud Carlos III (PI19-00013)
- Lluis Espinosa
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Kelly G Ten Hagen, National Institutes of Health, United States
Publication history
- Received: September 17, 2021
- Preprint posted: September 19, 2021 (view preprint)
- Accepted: February 4, 2022
- Accepted Manuscript published: February 8, 2022 (version 1)
- Version of Record published: February 15, 2022 (version 2)
Copyright
© 2022, Cantero-Recasens et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Reversing chemorefraction in colorectal cancer cells by controlling mucin secretion
eLife 11:e73926.
https://doi.org/10.7554/eLife.73926
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Genetic variation at the MTIF3 (Mitochondrial Translational Initiation Factor 3) locus has been robustly associated with obesity in humans, but the functional basis behind this association is not known. Here, we applied luciferase reporter assay to map potential functional variants in the haplotype block tagged by rs1885988 and used CRISPR-Cas9 to edit the potential functional variants to confirm the regulatory effects on MTIF3 expression. We further conducted functional studies on MTIF3-deficient differentiated human white adipocyte cell line (hWAs-iCas9), generated through inducible expression of CRISPR-Cas9 combined with delivery of synthetic MTIF3-targeting guide RNA. We demonstrate that rs67785913-centered DNA fragment (in LD with rs1885988, r2 > 0.8) enhances transcription in a luciferase reporter assay, and CRISPR-Cas9-edited rs67785913 CTCT cells show significantly higher MTIF3 expression than rs67785913 CT cells. Perturbed MTIF3 expression led to reduced mitochondrial respiration and endogenous fatty acid oxidation, as well as altered expression of mitochondrial DNA-encoded genes and proteins, and disturbed mitochondrial OXPHOS complex assembly. Furthermore, after glucose restriction, the MTIF3 knockout cells retained more triglycerides than control cells. This study demonstrates an adipocyte function-specific role of MTIF3, which originates in the maintenance of mitochondrial function, providing potential explanations for why MTIF3 genetic variation at rs67785913 is associated with body corpulence and response to weight loss interventions.
