Checkpoint Genes at the Cancer Side of the Immunological Synapse in Bladder Cancer.

Immune checkpoint inhibitors have revolutionized cancer therapy, but not all cancers respond to the currently available drugs, and even within cancers considered responsive to such modality, response rates range between 15 and 40%, depending on the cancer type, the line of treatment, and yet unknown clinical/molecular factors. Coordinated expression of checkpoint proteins was shown to occur on T cells, probably allowing fine-tuning of the signal transmitted to the cell. We performed a bioinformatic analysis of the expression of putative checkpoint mRNAs at the cancer side of the immunological synapse from the bladder cancer tumorgenome atlas (TCGA) database. Fifteen mRNAs, corresponding to both coinhibitory and costimulatory checkpoints, were shown to be expressed above a designated threshold. Of these, seven mRNAs were found to be coexpressed: CD277, PD-1L, CD48, CD86, galectin-9, TNFRSF14 (HVEM), and CD40. The expression of 2 of these mRNAs-BTN3A1 (CD277) and TNFRSF14 (HVEM)-was positively correlated with overall survival in the TCGA database. All these seven mRNA share putative binding sites of a few transcription factors (TFs). Of these, the expression of the TF BACH-2 was positively correlated with the expression of checkpoint mRNAs from the network. This suggests a joint transcriptional regulation on the expression of checkpoint mRNAs at the bladder tumor side of the immunological synapse.

TNFSF4 (OX40L) expression and survival in locally advanced and metastatic melanoma.

Immunotherapy with checkpoint inhibitors revolutionized melanoma treatment in both the adjuvant and metastatic setting, yet not all metastatic patients respond, and metastatic disease still often recurs among immunotherapy-treated patients with locally advanced disease. TNFSF4 is a co-stimulatory checkpoint protein expressed by several types of immune and non-immune cells, and was shown in the past to enhance the anti-neoplastic activity of T cells. Here, we assessed its expression in melanoma and its association with outcome in locally advanced and metastatic disease. We used publicly available data from The Cancer Genome Atlas (TCGA) and the Cancer Cell Line Encyclopedia (CCLE), and RNA sequencing data from anti-PD1-treated patients at Sheba medical center. TNFSF4 mRNA is expressed in melanoma cell lines and melanoma samples, including those with low lymphocytic infiltrates, and is not associated with the ulceration status of the primary tumor. Low expression of TNFSF4 mRNA is associated with worse prognosis in all melanoma patients and in the cohorts of stage III and stage IIIc-IV patients. Low expression of TNFSF4 mRNAs is also associated with worse prognosis in the subgroup of patients with low lymphocytic infiltrates, suggesting that tumoral TNFSF4 is associated with outcome. TNFSF4 expression was not correlated with the expression of other known checkpoint mRNAs. Last, metastatic patients with TNFSF4 mRNA expression within the lowest quartile have significantly worse outcome on anti-PD1 treatment, and a significantly lower response rate to these agents. Our current work points to TNFSF4 expression in melanoma as a potential determinant of prognosis, and warrants further translational and clinical research.