GSK3β serves as a novel therapeutic target in patients with type 2 diabetes mellitus complicated by colorectal cancer

Abstract

In clinical practice, tumor occurrence and progression appear to be more frequent and rapid in patients with type 2 diabetes mellitus (T2DM) compared to non-diabetic individuals. Epidemiological studies have confirmed that the incidence of colorectal cancer (CRC) is relatively higher in patients with T2DM. However, the key candidate regulatory factors that mediate and drive the concurrent development and progression of T2DM and CRC remain unclear. Analysis using the Significant Bias Evaluation Method on clinical data revealed that patients with T2DM have a higher propensity for developing lung cancer, colorectal cancer, and breast cancer. Further analysis of the key factors associated with T2DM and related tumors identified GSK3β as a potential key regulatory factor in CRC development in T2DM patients, through differential expression analysis using the limma package on real-world data. Western blot and qRT-PCR validation revealed that, compared to the non-insulin-resistant HT29 CRC cell line group, the mRNA and protein expression levels of GSK3β were significantly elevated in the insulin-resistant group. Similarly, the mRNA and protein expression levels of factors associated with the GSK3β-β-catenin-CyclinD1/cMyc pathway were also upregulated. Furthermore, when GSK3β was silenced or overexpressed, the proliferative effect of tumor cells was markedly reduced or increased, respectively. In summary, GSK3β is upregulated in T2DM patients with CRC and contributes to tumor progression. GSK3β holds promise as a novel therapeutic target for the treatment of patients with T2DM complicated by CRC, potentially providing a solution to address clinical challenges.

Keywords: GSK3β; Type 2 diabetes mellitus; bioinformation; colorectal cancer.

Figure 1

Clinical and molecular associations between T2DM and cancer. A. Clinical co-occurrence analysis shows that lung cancer, breast cancer, colon adenocarcinoma, rectal adenocarcinoma, and pancreatic cancer are significantly overrepresented in T2DM patients compared to random expectations (P < 0.001, Bonferroni-corrected). B. Network-based proximity analysis using PMM distance reveals that 15 cancer types, including pancreatic, thyroid, hepatocellular, breast, glioma, and lymphoma, are significantly closer to T2DM-related genes in the STRING PPI network (P < 0.05). C. Heatmap showing transcriptomic profiling from GSE115313, where hierarchical clustering of 260 differentially expressed genes distinguishes tumor tissues from adjacent normal tissues in T2DM-associated colorectal cancer patients. GSK3β, a predicted key mediator, is among the significantly dysregulated genes. Data are expressed as mean ± SD. *P < 0.05, **P < 0.01, ****P < 0.0001.

Figure 2

Insulin resistance promoted GSK3β expression and CRC cell proliferation via β-catenin-CyclinD1/cMyc signaling. A-C. qRT-PCR and Western blot showing elevated GSK3β mRNA and protein in IR cells. D. Immunofluorescent intensity of GSK3β was increased in IR cells. E. CCK-8 assay showing increased viability in IR cells compared to NC cells. F. No significant difference in apoptosis rate between IR and NC groups. G, H. β-catenin, CyclinD1, and cMyc mRNA and protein levels are significantly increased in IR vs. NC group. *P < 0.05, **P < 0.01, ****P < 0.0001.

Figure 3

GSK3β regulated β-catenin-CyclinD1/cMyc expression in insulin-resistant CRC cells. A, B. GSK3β silencing significantly reduced mRNA and protein levels of GSK3β, β-catenin, CyclinD1, and cMyc through western blotting and qRT-PCR. C, D. GSK3β overexpression (OE) significantly upregulated protein and mRNA levels of these targets. E, F. Immunofluorescence shows successful knockdown and overexpression of GSK3β. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.

Figure 4

EdU and colony formation assays revealed GSK3β-dependent proliferation in insulin-resistant CRC cells. (A-C) EdU assay shows that proliferation was significantly increased in insulin-resistant CRC cells (A), enhanced in GSK3β overexpression group (B), and decreased in GSK3β-silenced group (C). (D-F) Colony formation assay confirms that cell proliferation was significantly promoted by insulin resistance (D) and GSK3β overexpression (E), while reduced by GSK3β knockdown (F). **P < 0.01, ***P < 0.001, ****P < 0.0001.