A molecular subtype of colorectal cancers initiates independently of epidermal growth factor receptor and has an accelerated growth rate mediated by IL10-dependent anergy

Increased protein expression of interleukin-10 and its signalling molecules in colon cancer progression: potential prognostic and therapeutic targets

BACKGROUND

Interleukin-10 (IL-10) regulates immune responses in solid tumours, but its role in colorectal cancer (CRC) is unclear due to inconsistent findings. Tumour location is a critical prognostic factor, with proximal tumours often linked to worse outcomes. However, the relationship between IL-10 expression and tumour site is poorly understood.

METHODS

Protein expression of IL-10, its α-receptor (IL10Rα), and intracellular signal transducer (STAT3) was measured by immunohistochemistry in archived paired non-cancerous and cancerous colonic specimens collected from the same patients (n = 120). The data were then stratified according to clinical stages (early-stage I/II vs. late-stage III/IV) and tumour sites (right-sided cancers; RSCs vs. left-sided cancers; LSCs). Functional effects of biologically active IL-10 protein (0.1, 1, and 40 ng/ml), anti-IL10Rα monoclonal antibody (0.1, 1, and 40 ng/ml), and a single concentration of a specific STAT3 inhibitor (2 µM) on cell cycle and apoptosis were assessed in HT29 and SW620 CRC cell lines, along with the expression of key regulatory molecules.

RESULTS

Overall, protein expression of IL-10, IL10Rα, and STAT3 was significantly higher in malignant tissues compared to non-malignant tissues. Early and late-stage RSCs exhibited markedly increased expression of these proteins relative to LSCs, with the highest levels observed in late-stage RSCs. Elevated protein levels of all molecules correlated with high-grade tumours, mucinous histology, lymph node metastasis, and advanced cancer stage. While IL-10 treatment showed minimal effects, IL-10Rα blockade or STAT3 inhibition led to cell cycle arrest and apoptosis in HT29 and SW620 cells, associated with increased p21, p27, and Caspase-3, and decreased CCND1, CCND3, PCNA, and survivin gene and protein expression.

CONCLUSIONS

IL-10 and its signalling molecules increased in CRC progression, particularly in RSCs, suggesting their potential oncogenic roles and prognostic significance. Furthermore, targeting IL-10 signalling pathways could offer a promising avenue for CRC treatment. However, further studies are required to explore the IL-10 system in relation to tumour consensus molecular subtypes to better elucidate its biological functions and prognostic values in CRC.

Mechanism and strategies of immunotherapy resistance in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world. Although there are standard treatment options for CRC, most patients respond poorly to these treatments. Immunotherapies have gradually emerged due to the increasing awareness and understanding of tumor immunity, exhibiting good therapeutic efficacy in various cancers. Immunotherapies include cytokines, immune checkpoint inhibitors (ICIs), and adoptive cell therapies. In particular, ICIs, which are antibodies against cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed cell death 1 (PD-1), or its ligand PD-L1, have been successfully applied clinically for solid tumors, relieving the inhibitory effect of the tumor microenvironment on T cells. However, only a minority of patients with cancer achieve a durable clinical response during immunotherapy. Several factors restrict the efficacy of immunotherapy, leading to the development of drug resistance. In this review, we aimed to discuss the current status of immunotherapy for CRC and elaborate on the mechanisms that mediate resistance to immunotherapy and other potential therapeutic strategies.

Epithelial-specific ERBB3 deletion results in a genetic background-dependent increase in intestinal and colon polyps that is mediated by EGFR

ERBB3 has gained attention as a potential therapeutic target to treat colorectal and other types of cancers. To confirm a previous study showing intestinal polyps are dependent upon ERBB3, we generated an intestinal epithelia-specific ERBB3 deletion in C57BL/6-ApcMin/+ mice. Contrary to the previous report showing a significant reduction in intestinal polyps with ablation of ERBB3 on a B6;129 mixed genetic background, we observed a significant increase in polyp number with ablation of ERBB3 on C57BL/6J compared to control littermates. We confirmed the genetic background dependency of ERBB3 by also analyzing polyp development on B6129 hybrid and B6;129 advanced intercross mixed genetic backgrounds, which showed that ERBB3 deficiency only reduced polyp number on the mixed background as previously reported. Increased polyp number with ablation of ERBB3 was also observed in C57BL/6J mice treated with azoxymethane showing the effect is model independent. Polyps forming in absence of ERBB3 were generally smaller than those forming in control mice, albeit the effect was greatest in genetic backgrounds with reduced polyp numbers. The mechanism for differential polyp number in the absence of ERBB3 was through altered proliferation. Backgrounds with increased polyp number with loss of ERBB3 showed an increase in cell proliferation even in non-tumor epithelia, while backgrounds showing reduced polyp number with loss of ERBB3 showed reduced cellular proliferation. Increase polyp number caused by loss of ERBB3 was mediated by increased epidermal growth factor receptor (EGFR) expression, which was confirmed by deletion of Egfr. Taken together, this study raises substantial implications on the use of ERBB3 inhibitors against colorectal cancer. The prediction is that some patients may have increased progression with ERBB3 inhibitor therapy, which is consistent with observations reported for ERBB3 inhibitor clinical trials.