TAK1 expression is associated with increased PD-L1 and decreased cancer-specific survival in microsatellite-stable colorectal cancer

Background: Transforming growth factor β-activated protein kinase-1 (TAK1) plays an important role in MAPK and NFκB pathways and has been associated with colorectal cancer. The aim of this study was to determine how cytoplasmic and juxtanuclear punctate staining of TAK1 relates to immune checkpoint expression and cancer specific survival in colorectal cancer. Methods: Protein expression was assessed by immunohistochemistry on tissue microarrays from primary curative colorectal cancer resected specimens. Expression levels of cytoplasmic TAK1 by QuPath digital quantification and punctate TAK1 staining was scored using a manual point scoring technique and correlated with clinicopathological features, immune checkpoint expression and cancer-specific survival. Bulk RNA sequencing was performed in specimens to determine mutational profiles and differentially expressed genes. Results: A cohort of 875 patients who had undergone colorectal cancer resection were assessed for TAK1 expression. Higher levels of cytoplasmic TAK1 expression correlated with elevated PD1 and PD-L1 expression (p < 0.010). High punctate TAK1 expression was more commonly identified in poorly differentiated colorectal cancers (p = 0.036), had dysregulated mutational and transcriptional profiles with decreased insulin-like growth factor 2(IGF2) expression (p < 0.010), and independently predicted poor cancer-specific survival (HR 2.690, 95% CI 1.419–5.100, p = 0.002). The association of punctate TAK1 expression and recurrence remained after subgroup analysis for microsatellite-stable colorectal cancer (p = 0.028). Discussion: Punctate TAK1 expression is associated with worse cancer specific survival. TAK1 signalling may be an important pathway to investigate underlying mechanisms for recurrence in microsatellite-stable colorectal cancer

Radiation-induced changes in gene expression in rectal cancer specimens

PURPOSE: The standard-of-care for locally advanced rectal cancer is radiotherapy-based neoadjuvant therapy followed by surgical resection. This article reviews the evidence of molecular changes at the transcriptome level induced through radiotherapy in rectal cancer.METHODS: The PubMed search "(radiation OR radiotherapy) cancer (transcriptome OR "gene expression") rectal" was used. The studies taken forward utilised gene-expression data on both pre-treatment and post-treatment rectal adenocarcinoma biospecimens from patients treated with RT-based neoadjuvant strategies.RESULTS: Twelve publications met the review criteria. There was variation in approaches in terms of design, patient population, cohort size, timing of the post-radiotherapy sampling and method of measuring gene expression. Most of the post-treatment biospecimen retrievals were at resection. The literature indicates a broad upregulation of immune activity through radiotherapy using gene-expression data.CONCLUSION: Future studies would benefit from standardised prospective approaches to sampling to enable the inclusion of timepoints relevant to the tumour and immune response.</p

Association of Wnt Signalling With Metachronous Colonic Polyp Risk

Background: Following colorectal polypectomy, 20-50% of patients develop metachronous polyps, and a proportion have increased colorectal cancer (CRC) risk. However, there are currently no molecular biomarkers for predicting metachronous polyp risk. Constitutive activation of the Wnt signalling cascade is a hallmark of polyp development and carcinogenesis, therefore biomarkers from this pathway were investigated for association with detection of metachronous polyps. Methods: A retrospective study was performed on a tissue microarray (TMA) of left sided colonic polyps from 279 patients undergoing screening polypectomy (May’09-Dec’16) followed by surveillance colonoscopy (up to 6 years). Mutational analysis was performed using the GPOL cancer plus panel, protein expression by Immunohistochemistry and RNA-sequencing by TempO-Seq (BioClavis). Log rank statistics determined associations with time to detection of metachronous polyp. Index polyp number, histology and size were compared to metachronous lesion outcome using χ2/ANOVA and multivariate polynomial regression identified independent predictors of advanced future lesions. Results: APC (91%), KRAS (30%) and SOX9 (23%) were the most frequently mutated genes and APC and SOX9 are both implicated in Wnt signalling. Mutations in APC and co-mutations in SOX9 with ARID1 were associated with a shorter time to detection of metachronous polyps. Neither variant classification nor location of mutations were associated with metachronous polyp detection. Luminal epithelial cells with high expression of E-Cadherin or SOX9 were significantly associated with earlier detection of metachronous polyps or CRC (HR 2.3, 95%CI 1.6-3.3: p&lt;0.001 and: HR 2.0, 95%CI 1.3-3.0; p=0.001 respectively). By χ2/ANOVA analysis, E-Cadherin and SOX9 expression was associated with detection of metachronous polyp (p&gt;0.001, p=0.037 respectively). On multivariate regression, number of polyps (HR 1.2, 95%CI 1.1-1.3; p&lt;0.001), and E-Cadherin expression (HR 2.1, 95%CI 1.5-3; p&lt;0.001), independently predicted metachronous lesions. Gene set enrichment analysis (GSEA) was used to explore differential biology between high and low E-Cadherin or SOX9 expression. For E-Cadherin, all seven immune-annotated MSigDB hallmarks had negative enrichment, however Wnt--catenin signaling was positively enriched (NES=1.50, p-adj&lt;0.1). The top signature enriched for SOX9 was ‘NFB signaling via TNF (NES=1.70, p-adj&lt;0.001). The LGR5 stemness signature was enriched in both high E-Cadherin (NES=1.97 p-adj&lt;0.0001) and high SOX9 (NES=1.48, p-adj&lt;0.0001) groups. Conclusions: Wnt signalling-associated protein expression within index polyp tissue is valuable for predicting metachronous polyp risk. In addition, expression of E-Cadherin and SOX9 in colonic polyps are linked to immune and stemness signatures, suggesting immune and stemness biology may be an underlying driver of metachronous polyp development

Innate immune receptor C5aR1 regulates cancer cell fate and can be targeted to improve radiotherapy in tumours with immunosuppressive microenvironments

An immunosuppressive microenvironment causes poor tumor T cell infiltration and is associated with reduced patient overall survival in colorectal cancer. How to improve treatment responses in these tumors is still a challenge. Using an integrated screening approach to identify cancer-specific vulnerabilities, we identified complement receptor C5aR1 as a druggable target, which when inhibited improved radiotherapy, even in tumors displaying immunosuppressive features and poor CD8+ T cell infiltration. While C5aR1 is well-known for its role in the immune compartment, we found that C5aR1 is also robustly expressed on malignant epithelial cells, highlighting potential tumor cell-specific functions. C5aR1 targeting resulted in increased NF-κB-dependent apoptosis specifically in tumors and not normal tissues, indicating that, in malignant cells, C5aR1 primarily regulated cell fate. Collectively, these data revealed that increased complement gene expression is part of the stress response mounted by irradiated tumors and that targeting C5aR1 could improve radiotherapy, even in tumors displaying immunosuppressive features