Inhibition of YAP/TAZ-driven TEAD activity prevents growth of NF2-null schwannoma and meningioma.

Schwannoma tumours typically arise on the eighth cranial nerve and are mostly caused by loss of the tumour suppressor Merlin (NF2). There are no approved chemotherapies for these tumours and the surgical removal of the tumour carries a high risk of damage to the eighth or other close cranial nerve tissue. New treatments for schwannoma and other NF2-null tumours such as meningioma are urgently required. Using a combination of human primary tumour cells and mouse models of schwannoma, we have examined the role of the Hippo signalling pathway in driving tumour cell growth. Using both genetic ablation of the Hippo effectors YAP and TAZ as well as novel TEAD palmitoylation inhibitors, we show that Hippo signalling may be successfully targeted in vitro and in vivo to both block and, remarkably, regress schwannoma tumour growth. In particular, successful use of TEAD palmitoylation inhibitors in a preclinical mouse model of schwannoma points to their potential future clinical use. We also identify the cancer stem cell marker aldehyde dehydrogenase 1A1 (ALDH1A1) as a Hippo signalling target, driven by the TAZ protein in human and mouse NF2-null schwannoma cells, as well as in NF2-null meningioma cells, and examine the potential future role of this new target in halting schwannoma and meningioma tumour growth.

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.

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

BACKGROUND: Transforming growth factor ß-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.

Improving radiotherapy in immunosuppressive microenvironments by targeting complement receptor C5aR1.

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.