The microRNA-183/96/182 cluster inhibits lung cancer progression and metastasis by inducing an interleukin-2-mediated antitumor CD8⁺ cytotoxic T-cell response

Abstract

One of the mechanisms by which cancer cells acquire hyperinvasive and migratory properties with progressive loss of epithelial markers is the epithelial-to-mesenchymal transition (EMT). We have previously reported that in different cancer types, including nonsmall cell lung cancer (NSCLC), the microRNA-183/96/182 cluster (m96cl) is highly repressed in cells that have undergone EMT. In the present study, we used a novel conditional m96cl mouse to establish that loss of m96cl accelerated the growth of Kras mutant autochthonous lung adenocarcinomas. In contrast, ectopic expression of the m96cl in NSCLC cells results in a robust suppression of migration and invasion in vitro, and tumor growth and metastasis in vivo. Detailed immune profiling of the tumors revealed a significant enrichment of activated CD8+ cytotoxic T lymphocytes (CD8+ CTLs) in m96cl-expressing tumors, and m96cl-mediated suppression of tumor growth and metastasis was CD8+ CTL-dependent. Using coculture assays with naïve immune cells, we show that m96cl expression drives paracrine stimulation of CD8+ CTL proliferation and function. Using tumor microenvironment-associated gene expression profiling, we identified that m96cl elevates the interleukin-2 (IL2) signaling pathway and results in increased IL2-mediated paracrine stimulation of CD8+ CTLs. Furthermore, we identified that the m96cl modulates the expression of IL2 in cancer cells by regulating the expression of transcriptional repressors Foxf2 and Zeb1, and thereby alters the levels of secreted IL2 in the tumor microenvironment. Last, we show that in vivo depletion of IL2 abrogates m96cl-mediated activation of CD8+ CTLs and results in loss of metastatic suppression. Therefore, we have identified a novel mechanistic role of the m96cl in the suppression of lung cancer growth and metastasis by inducing an IL2-mediated systemic CD8+ CTL immune response.

Harnessing epithelial-mesenchymal plasticity to boost cancer immunotherapy

“…Ectopic expression of m96cl resulted in inhibition of migration and invasion, tumor growth and metastasis. This was found to depend on the induction of interleukin 2-mediated anti-cancer CD8 + cytotoxic T cell response [ 208 ].…”

EMT-activated secretory and endocytic vesicular trafficking programs underlie a vulnerability to PI4K2A antagonism in lung cancer

“…Chromatin immunoprecipitation. As previously described (21), lysates from siRNA-transfected H1299 cells were subjected to cross-linking followed by sonication and immunoprecipitation with anti-RNA polymerase II or anti-rabbit IgG (Santa Cruz). Genomic DNA was eluted and purified using the MinElute Reaction Cleanup kit (Qiagen) and subjected to quantitative PCR.…”

“…EMT-activating transcription factors (EMT-TFs) (e.g., ZEB and SNAIL families and basic helix-loop-helix transcription factors such as TWIST) govern large transcriptomes in part by silencing microRNAs (miRs) that target mRNAs encoding functionally diverse proteins, including EMT-activating transcription factors themselves, creating a feedforward loop that drives EMT (17,18). In lung cancer and other tumor types, the pro-metastatic activity of ZEB1 resides largely in its capacity to silence miR-200, miR-182/183, miR-34a, and miR-148a (19)(20)(21)(22)(23).…”

Remodeling the tumor immune microenvironment with oncolytic viruses expressing miRNAs

“…Ectopic expression of m96cl was shown to inhibit in vivo tumor growth and metastasis through IL2-mediated stimulation of CD8+ CTLs, by targeting Foxf2 and Zeb1. Depletion of IL-2 resulted in the loss of m96cl/IL2-activated CD8+ CTLs and recovery of metastatic properties ( 16 ). Moreover, it was demonstrated in mouse models of adoptive cell therapy that the antitumor activity of CD8+ CTLs could be further stimulated through the transduction of miR-200c and subsequent repression of Zeb1 ( 17 ).…”