Georgieva Teodora G, Darmoul Dalila, Chen Hwudaurw, Cui Haiyan, Rice Photini F S, Barton Jennifer K, Besselsen David G, Ignatenko Natalia A
Genetically Engineered Mouse Models Core, The University of Arizona Bio5 Institute, Tucson, AZ 85721-0240, USA.
Department of Cellular and Molecular Medicine, The University of Arizona Cancer Center, Tucson, AZ 85724-5024, USA.
Cancers (Basel). 2024 Nov 15;16(22):3842. doi: 10.3390/cancers16223842.
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 tumor suppressor gene. A first analysis of KLK6 expression in the intestinal tract of -mutant multiple intestinal neoplasia () mice revealed up to four-fold induction of mRNA levels in adenomas relative to its level in the adjacent mucosa.
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 -mutant intestinal and colon tumorigenesis, we engineered a mouse with floxed alleles of the gene () and crossed it with a mouse expressing the truncated APC protein under control of the intestinal tract-specific human transgene (;). We found that mice with disrupted gene expression (;) had a significantly smaller average size of the small intestinal and colon crypts ( < 0.001 and = 0.04, respectively) and developed a significantly fewer adenomas ( = 0.01). Moreover, a decrease in high-grade adenomas ( = 0.03) and adenomas with a diameter above 2 mm ( < 0.0001) was noted in ; mice. Further molecular analysis showed that gene inactivation in the small intestine and colon tissues of ; mice resulted in a significant suppression of transforming growth factor β2 (TGF-β2) protein ( ≤ 0.02) and mitogen-activated protein kinase (MAPK) phosphorylation ( ≤ 0.01).
These findings demonstrate the oncogenic role of KLK6 in the mutant -mediated intestinal tumorigenesis and suggest the utility of KLK6 for early diagnosis of colorectal tumors.
背景/目的：本研究的目的是评估一种分泌型丝氨酸蛋白酶——激肽释放酶相关肽酶6（KLK6）在由突变肿瘤抑制基因驱动的结直肠癌发生过程中的作用。对突变型多发性肠道肿瘤（Min）小鼠肠道中KLK6表达的初步分析显示，腺瘤中mRNA水平相对于相邻黏膜中的水平高达四倍诱导。
通过免疫组织化学和光学相干断层扫描/激光诱导荧光（OCT/LIF）成像证实腺瘤区域存在KLK6蛋白。为了评估KLK6表达对Min突变型肠道和结肠肿瘤发生的贡献，我们构建了一种带有该基因（Apc）floxed等位基因的小鼠，并将其与在肠道特异性人绒毛蛋白（Villin）转基因（Villin-cre）控制下表达截短APC蛋白的小鼠杂交。我们发现，KLK6基因表达被破坏的小鼠（Villin-cre/Apcflox/flox）小肠和结肠隐窝的平均大小显著更小（分别为P<0.001和P = 0.04），且发生的腺瘤显著更少（P = 0.01）。此外，在Villin-cre/Apcflox/flox小鼠中，高级别腺瘤减少（P = 0.03），直径大于2 mm的腺瘤减少（P<0.0001）。进一步的分子分析表明，Villin-cre/Apcflox/flox小鼠小肠和结肠组织中的KLK6基因失活导致转化生长因子β2（TGF-β2）蛋白显著抑制（P≤0.02）和丝裂原活化蛋白激酶（MAPK）磷酸化显著抑制（P≤0.01）。
这些发现证明了KLK6在突变型Apc介导的肠道肿瘤发生中的致癌作用，并提示KLK6在结直肠癌早期诊断中的应用价值。
