Activation of YAP, a Hippo pathway effector, is an important resistance mechanism to BRAF inhibitor (BRAFi) in melanoma. Emerging evidence also suggests that YAP is involved in suppression of the antitumor immune response. However, the potential direct impact of YAP activity on cytotoxic T-cell immune responses has not been explored yet. Here, we show that BRAFi-resistant melanoma cells evade CD8+ T-cell immune responses in a PD-L1–dependent manner by activating YAP, which synchronously supports melanoma cell survival upon BRAF inhibition. PD-L1 expression is elevated in BRAFi-resistant melanoma cells, in which YAP is robustly activated, and YAP knockdown decreases PD-L1 expression. In addition, constitutively active YAP (YAP-5SA) increases PD-L1 expression by binding to an upstream enhancer of the PD-L1 gene and potentiating its transcription. Both BRAFi-resistant and YAP-5SA–expressing melanoma cells suppress the cytotoxic function and cytokine production of Melan-A–specific CD8+ T cells, whereas anti–PD-1 antibody reverses the YAP-mediated T-cell suppression. Moreover, nuclear enrichment of YAP in clinical melanoma samples correlates with increased PD-L1 expression. Our findings show that YAP directly mediates evasion of cytotoxic T-cell immune responses in BRAFi-resistant melanoma cells by upregulating PD-L1, and targeting of YAP-mediated immune evasion may improve prognosis of melanoma patients. Cancer Immunol Res; 6(3); 255–66. ©2018 AACR.

VEGF-A drives T cell exhaustion via TOX-dependent transcriptional programming in microsatellite stable colorectal cancers.

During cancer immunoediting, loss of major histocompatibility complex class I (MHC-I) in neoplasm contributes to the evasion of tumours from host immune system. Recent studies have demonstrated that most natural killer (NK) cells that are found in advanced cancers are defective, releasing the malignant MHC-I-deficient tumours from NK-cell-dependent immune control. Here, we show that a natural killer T (NKT)-cell-ligand-loaded tumour-antigen expressing antigen-presenting cell (APC)-based vaccine effectively eradicates these advanced tumours. During this process, we find that the co-expression of Tim-3 and PD-1 marks functionally exhausted NK cells in advanced tumours and that MHC-I downregulation in tumours is closely associated with the induction of NK-cell exhaustion in both tumour-bearing mice and cancer patients. Furthermore, the recovery of NK-cell function by IL-21 is critical for the anti-tumour effects of the vaccine against advanced tumours. These results reveal the process involved in the induction of NK-cell dysfunction in advanced cancers and provide a guidance for the development of strategies for cancer immunotherapy.

The BJC is owned by Cancer Research UK, a charity dedicated to understanding the causes, prevention and treatment of cancer and to making sure that the best new treatments reach patients in the clinic as quickly as possible. The journal reflects these aims. It was founded more than fifty years ago and, from the start, its far-sighted mission was to encourage communication of the very best cancer research from laboratories and clinics in all countries. The breadth of its coverage, its editorial independence and it consistent high standards, have made BJC one of the world's premier general cancer journals. Its increasing popularity is reflected by a steadily rising impact factor.

BACKGROUND: In colorectal cancer (CRC), DNA methylation anomalies define distinct subgroups termed CpG island methylator phenotype 1 (CIMP1), CIMP2, and CIMP‐negative. The role of this classification in predicting recurrence and disease‐free survival (DFS) in resected stage III CRC was evaluated.METHODS: Sporadic cancers from 161 patients were analyzed. Bisulfite pyrosequencing was used to examine the methylation of 2 global DNA methylation markers (LINE‐1, Alu) and 9 loci (MINT1, MINT2, MINT31, P16, hMLH1, P14, SFRP1, SFRP2, and WNT5A). Mutations in BRAF and KRAS were assayed.RESULTS: Gene hypermethylation clustered in discrete groups of patients, indicating the presence of CIMP. K‐means clustering analysis identified 3 discrete subgroups: CIMP1 (n = 22, 13.7%), associated with proximal location and BRAF mutations; CIMP2 (n = 40, 24.8%), associated with KRAS mutations; and CIMP‐negative (n = 99, 61.5%), associated with distal location. In proximal CRC, CIMP1 was correlated with a higher recurrence rate (53% for CIMP1, 18% for CIMP2, and 26% for CIMP‐negative) and a worse DFS (P = .015). Also in proximal CRC, LINE‐1 methylation was lower in patients whose cancer recurred compared with those whose cancer did not recur (P = .049). In multivariate analysis, CIMP1 and low LINE1 methylation were independent prognostic factors for DFS in proximal CRC (P = .008 for classification by K‐means clustering analysis; P = .040 for LINE‐1 methylation status).CONCLUSIONS: DNA methylation is a useful biomarker of recurrence in resected stage III proximal but not distal CRC. However, as the number of CIMP1 cases was small in distal CRC, further study is required to validate our findings. Cancer 2011. © 2010 American Cancer Society.

Purpose: This study was designed to evaluate the efficacy and toxicity of erlotinib in patients with advanced non–small-cell lung cancer (NSCLC) who experienced disease progression after treatment with gefitinib.Patients and Methods: The study included stage IIIB/IV recurrent or metastatic NSCLC patients who received two or three prior chemotherapy regimens and showed progressive disease within 4 months of gefitinib therapy discontinuation. Patients received erlotinib 150 mg/d until disease progression or unacceptable toxicity. Epidermal growth factor receptor (EGFR) mutations and other genetic abnormalities were analyzed from available tumor samples.Results: Patient and disease characteristics (N = 21) included median age 56 years; number of prior chemotherapy regimens (three; n = 11); female sex (n = 11); adenocarcinoma (n = 15); and never-smoker status (n = 11). Among the 17 patients with tumor samples available, EGFR mutations were detected in five. The disease control rate (DCR) and response rate (RR) for all patients were 28.6% and 9.5%, respectively. The median duration of disease control was 125 days. The median time to progression and overall survival were 60 days and 158 days, respectively. Patients who had stable disease (SD) while receiving gefitinib showed significantly higher DCR (75% v 17.6% in non-SD patients; P = .050) and RR (50.0% v 0% in non-SD patients; P = .029). Among 17 patients with biomarker results available, those lacking EGFR mutations who had SD while receiving gefitinib showed significantly higher DCR and RR.Conclusion: Erlotinib seems to be a potential therapeutic option for the treatment of advanced NSCLC patients with wild-type EGFR who had SD while receiving gefitinib.