376P - Crosstalk Between CAFs and Cancer Cells is mediated by hMENA-regulated secretory autophagy and affects immunotherapy response in NSCLC

Background

The crosstalk between cancer-associated fibroblasts (CAFs) and cancer cells is a driver of non-small cell lung cancer (NSCLC) progression and resistance to Immune checkpoint therapy (ICT). We have reported on the role of the actin cytoskeleton regulatory protein hMENA and its isoform hMENAΔv6 in this process, mainly through cytokine secretion. Autophagy, a self-degradative mechanism, is recognized to facilitate unconventional protein secretion. Autophagy inhibitors are under investigation combined with ICT.

Methods

CAFs were isolated from NSCLC patient tissues undergoing curative surgery. siRNA, qRT-PCR, WB, IF, electron microscopy and ELISA were used to analyze hMENA/hMENAΔv6 role in autophagic protein secretion. Organotypic tissue slices (TS) were set, Hydroxychloroquine (HCQ) treated and analyzed by IHC. Computational analysis was employed to define a “secretory autophagy” gene signature, inferred from the NSCLC Cancer Genome Atlas (TCGA) and correlated with patient survival.

Results

We found that hMENA/hMENAΔv6 silencing in CAFs hinders autophagy and alters cytoskeletal tension inducing a mechanical stimulus which influences the autophagosome trafficking, leading to impaired unconventional protein secretion, with a reduction of immunomodulatory cytokines in CAF-conditioned medium (CM). CM from CAFs enhances NSCLC cell proliferation and shifts tumor cell metabolism towards aerobic glycolysis, as shown by increased lactate production and STAT3 activation. Conversely, hMENA/hMENAΔv6 as well as autophagy gene silencing in CAFs mitigates these effects. We set organotypic TS, treated with HCQ and then IHC evaluated for cell viability, hMENA expression in CAFs and immune cell infiltrate. A “secretory-autophagy gene signature” including ENAH (hMENA gene) was found enriched in hMENAΔv6^high TCGA patients and stratifies responder and non-responder ICT treated NSCLC patients in the OAK clinical trial dataset.

Conclusions

Our findings unveil a novel role for hMENA/hMENAΔv6 in mediating communication between cancer cells and CAFs through secretory autophagy. This highlights promising opportunities for developing novel combinatorial therapies to enhance responses to ICT in NSCLC

Legal entity responsible for the study

The authors

Funding

AIRC; Ministry of Health

Disclosure

All authors have declared no conflicts of interest.