BCG therapy downregulates HLA-I on malignant cells to subvert antitumor immune responses in bladder cancer
Mathieu Rouanne, … , Laurence Zitvogel, Aurélien Marabelle
Mathieu Rouanne, … , Laurence Zitvogel, Aurélien Marabelle
Published May 3, 2022
Citation Information: J Clin Invest. 2022;132(12):e145666. https://doi.org/10.1172/JCI145666.
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Research Article Immunology Oncology

BCG therapy downregulates HLA-I on malignant cells to subvert antitumor immune responses in bladder cancer

Abstract

Patients with high-risk, nonmuscle-invasive bladder cancer (NMIBC) frequently relapse after standard intravesical bacillus Calmette-Guérin (BCG) therapy and may have a dismal outcome. The mechanisms of resistance to such immunotherapy remain poorly understood. Here, using cancer cell lines, freshly resected human bladder tumors, and samples from cohorts of patients with bladder cancer before and after BCG therapy, we demonstrate 2 distinct patterns of immune subversion upon BCG relapse. In the first pattern, intracellular BCG infection of cancer cells induced a posttranscriptional downregulation of HLA-I membrane expression via inhibition of autophagy flux. Patients with HLA-I–deficient cancer cells following BCG therapy had a myeloid immunosuppressive tumor microenvironment (TME) with epithelial-mesenchymal transition (EMT) characteristics and dismal outcomes. Conversely, patients with HLA-I–proficient cancer cells after BCG therapy presented with CD8+ T cell tumor infiltrates, upregulation of inflammatory cytokines, and immune checkpoint–inhibitory molecules. The latter patients had a very favorable outcome. We surmise that HLA-I expression in bladder cancers at relapse following BCG does not result from immunoediting but rather from an immune subversion process directly induced by BCG on cancer cells, which predicts a dismal prognosis. HLA-I scoring of cancer cells by IHC staining can be easily implemented by pathologists in routine practice to stratify future treatment strategies for patients with urothelial cancer.

Authors

Mathieu Rouanne, Julien Adam, Camélia Radulescu, Diane Letourneur, Delphine Bredel, Séverine Mouraud, Anne-Gaëlle Goubet, Marion Leduc, Noah Chen, Tuan Zea Tan, Nicolas Signolle, Amélie Bigorgne, Michael Dussiot, Lambros Tselikas, Sandrine Susini, François-Xavier Danlos, Anna K. Schneider, Roman Chabanon, Sophie Vacher, Ivan Bièche, Thierry Lebret, Yves Allory, Jean-Charles Soria, Nicholas Arpaia, Guido Kroemer, Oliver Kepp, Jean Paul Thiery, Laurence Zitvogel, Aurélien Marabelle

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Figure 2

BCG induces EMT characteristics in the subset of HLA-I– cancer cells.

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BCG induces EMT characteristics in the subset of HLA-I– cancer cells. (A...
(A)Flow cytometric dot plot showing HLA-I+ and HLA-I– cancer cells among live cells following ex vivo BCG stimulation of fresh human tumors for 72 hours. (B) MFI of EpCAM (n = 12; 1-way ANOVA with Tukey’s post test) and relative proportions of proliferative Ki67+ and apoptotic annexin-V+ cells (n = 12; paired, 2-tailed t test) among live cancer cells by flow cytometry. (C) Flow cytometric dot plots for HLA-I and EpCAM expression in live cancer cells. Dot plots illustrate the control condition at the top and the BCG condition at the bottom. Cancer cells were ordered according to their baseline expression of EpCAM (MFI), ranging from the left (epithelial type, RT4) to the right (mesenchymal type, UM-UC3). (D) Cancer cells (RT4, 5637, and UM-UC3) were coincubated with BCG for 24 hours and sorted on the basis of their HLA-I membrane expression. Total RNA extraction of HLA-I+ and HLA-I– cancer cells was performed. (E) The EMT score based on NanoString IO360 transcriptomic data was obtained for HLA-I+ and HLA-I– cancer cells. HLA-I– 5637 cancer cells showed the strongest shift toward a mesenchymal score. (F) Unsupervised hierarchical clustering analysis of cancer cells according to EMT status, depicted per cell line (columns), HLA-I status (columns), and genes expressed (rows). (G) Epithelial (CDH1 [E-cadherin] and EPCAM) and mesenchymal (CDH11) absolute mRNA expression after BCG (red, EMThi UM-UC3 and 5637 HLA-I–; green, EMTlo RT4 and 5637 HLA-I+). Unpaired, 2-tailed t test. All data are presented as the mean ± SEM. *P < 0.05, **P < 0.005, ***P < 0.001.