Abstract 422P
Background
CLDN1 overexpression is associated with the stiffening of the tumour-stroma interface, which potentially inhibits infiltration of immune cells, in turn hindering the efficacy of ICI. Given recent evidence supporting ICI efficacy in NPC, we investigated whether CLDN1 is overexpressed in NPC and its association with the tumour immune microenvironment (TIME).
Methods
We performed RNA sequencing (RNAseq) for 156 NPC patients, with corresponding multiplex immunofluorescence (mIF) analyses on 16 patients. TIME profiling was performed using deconvolution methods (CIBERSORT, quanTIseq) on RNAseq to estimate proportions of immune subsets, and geneset enrichment analyses performed for immune-related pathways. For mIF, sequential stain-image-strip cycles was done with COMET (Lunaphore Technologies, CH) for 40 markers (including CK, PD-L1, CD8, CLDN1). We stratified tumours by their median CLDN1 expression and compared the immune profile of CLDN1high versus CLDN1low tumours.
Results
We observed CLDN1 overexpression in NPC versus normal tissues (P<0.001). Consistent with our hypothesis, we observed reduced abundance of most immune subsets in CLDN1high tumours post-deconvolution, notably CD8+ T cells (P<0.001), B cells (P=0.007) and macrophages (P=0.03). Immune genesets were similarly downregulated in CLDN1high vs CLDN1low tumours. From mIF, the ratio of immune to tumour cells was found to be lower in CLDN1highvs CLDN1low tumours, including that of CD8+ T cells (P=0.02), CD20+ B cells (P=0.01) and CD68+ macrophages (P=0.05), thereby corroborating our preceding observation of reduced immune infiltration in the TIME in CLDN1highNPC. Notably, PD-L1 expression by tumor proportion score (TPS) and composite proportion score (CPS) was higher in CLDN1high vs CLDN1low (P=0.01 and 0.03).
Conclusions
Here, we report the overexpression of CLDN1 in NPC that is associated with an immune-low TIME and high PD-L1 expression. Given the role of the tumour TIME in ICI response, our findings provide a rationale for future trials investigating combination of CLDN1 targeting with ICI to reverse this immune exclusion effect, potentially leading to improved outcomes.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
National Medical Research Council Singapore Clinician Scientist Award (NMRC/CSA-INV/0027/2018, CSAINV20nov-0021), Duke-NUS Oncology Academic Program, Goh Foundation Proton Research Program, NCCS Cancer Fund, Kua Hong Pak Head and Neck Cancer Research Program.
Disclosure
M.L.K. Chua: Financial Interests, Personal, Invited Speaker: Varian, AstraZeneca, Janssen, BeiGene, MSD, Bayer; Financial Interests, Personal, Member of Board of Directors: Digital Life Line; Financial Interests, Personal, Stocks/Shares: Digital Life Line; Financial Interests, Institutional, Advisory Board: Digital Life Line; Financial Interests, Institutional, Other, Research agreement: Decipher Biosciences; Financial Interests, Institutional, Research Grant, Grant for an IIT: BeiGene; Non-Financial Interests, Personal, Leadership Role: Head and Neck Cancer International Group; Non-Financial Interests, Personal, Principal Investigator, PI of an IIT partly sponsored by BeiGene: BeiGene; Non-Financial Interests, Personal, Member of Board of Directors, Board of Trustees and Chair of Scientific Committee: Alice's Arc; Non-Financial Interests, Personal, Leadership Role, Chair of ASCO Asia Pacific Regional Council: ASCO; Non-Financial Interests, Personal, Leadership Role, Chair of the ASCO Breakthrough Meeting 2024: ASCO. D.W. Lim: Financial Interests, Institutional, Advisory Board: MSD, Roche, Beigene, Daiichi Sankyo, Janssen; Financial Interests, Institutional, Trial Chair, Grant funding for investigator-sponsored study: Bristol Myers Squibb, Taiho Pharmaceuticals. All other authors have declared no conflicts of interest.