Kallikrein-Related Peptidase 6 Contributes to Murine Intestinal Tumorigenesis Driven by a Mutant Adenomatous polyposis coli Gene

Teodora G Georgieva; Dalila Darmoul; Hwudaurw Chen; Haiyan Cui; Photini F S Rice; Jennifer K Barton; David G Besselsen; Natalia A Ignatenko

doi:10.3390/cancers16223842

Kallikrein-Related Peptidase 6 Contributes to Murine Intestinal Tumorigenesis Driven by a Mutant Adenomatous polyposis coli Gene

Cancers (Basel). 2024 Nov 15;16(22):3842. doi: 10.3390/cancers16223842.

Authors

Teodora G Georgieva^{1

2}, Dalila Darmoul³, Hwudaurw Chen², Haiyan Cui², Photini F S Rice⁴, Jennifer K Barton⁴, David G Besselsen⁵, Natalia A Ignatenko^{2

6}

Affiliations

¹ Genetically Engineered Mouse Models Core, The University of Arizona Bio5 Institute, Tucson, AZ 85721-0240, USA.
² Department of Cellular and Molecular Medicine, The University of Arizona Cancer Center, Tucson, AZ 85724-5024, USA.
³ Institut de Biologie Paris-Seine, Sorbonne Université, UMR CNRS 8256, INSERM ERL U1164, Biological Adaptation and Ageing, 75005 Paris, France.
⁴ Department of Biomedical Engineering, The University of Arizona, Tucson, AZ 85721-0240, USA.
⁵ University Animal Care, The University of Arizona, Tucson, AZ 85721-0101, USA.
⁶ Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, AZ 85724-5024, USA.

Abstract

Background/objectives: The objective of this study was to assess the role of a secreted serine protease, kallikrein-related peptidase 6 (KLK6), during colorectal tumorigenesis driven by a mutant Adenomatous polyposis coli (APC) tumor suppressor gene. A first analysis of KLK6 expression in the intestinal tract of Apc-mutant multiple intestinal neoplasia (Apc^Min/+) mice revealed up to four-fold induction of Klk6 mRNA levels in adenomas relative to its level in the adjacent mucosa.

Methods and results: The presence of KLK6 protein in the adenomatous areas was confirmed by immunohistochemistry and optical coherence tomography/laser-induced fluorescence (OCT/LIF) imaging. To assess the contribution of the KLK6 expression on the Apc-mutant intestinal and colon tumorigenesis, we engineered a mouse with floxed alleles of the Klk6 gene (Klk6^lox/lox) and crossed it with a mouse expressing the truncated APC protein under control of the intestinal tract-specific human CDX2P9.5-NLS Cre transgene (CPC;Apc^fl/fl;Klk6^+/+). We found that CPC;Apc^fl/fl mice with disrupted Klk6 gene expression (CPC;Apc^fl/fl;Klk6^fl/fl) had a significantly smaller average size of the small intestinal and colon crypts (p < 0.001 and p = 0.04, respectively) and developed a significantly fewer adenomas (p = 0.01). Moreover, a decrease in high-grade adenomas (p = 0.03) and adenomas with a diameter above 2 mm (p < 0.0001) was noted in CPC;Apc^fl/fl;Klk6^fl/fl mice. Further molecular analysis showed that Klk6 gene inactivation in the small intestine and colon tissues of CPC;Apc^fl/fl;Klk6^fl/fl mice resulted in a significant suppression of transforming growth factor β2 (TGF-β2) protein (p ≤ 0.02) and mitogen-activated protein kinase (MAPK) phosphorylation (p ≤ 0.01).

Conclusions: These findings demonstrate the oncogenic role of KLK6 in the mutant Apc-mediated intestinal tumorigenesis and suggest the utility of KLK6 for early diagnosis of colorectal tumors.

Keywords: APC mutation; ERK1/2 mitogen-activated protein kinase; KLK6 conditional knockout mouse; kallikrein-related peptidase 6; transforming growth factor β2 isoform; β-catenin.

Grants and funding

R01CA157595, R01CA109385/GF/NIH HHS/United States