Outcome of non-small cell lung cancer patients, disaggregated according to gender, PD-L1 and ERα levels. Best response (PD: progressive disease; PR: partial response; SD: stable disease) after 6 months from the beginning of pembrolizumab treatment as first-line monotherapy, PFS and OS (Kapan-Meier and log-rank test) were analyzed in 35 NSCLC patients (15 females; 20 males). a-c. Female (F) and male (M) patients were stratified in CD274/PD-L1low and CD274/PD-L1high, according to the median value of the CD274/PD-L1mRNA, measured by RT-PCR in the tumor samples (technical triplicates). d-f. F and M patients were stratified in ESR1/ERαlow and ESR1/ERαhigh, according to the median value of the ESR1/ERα mRNA, measured by RT-PCR in the tumor samples (technical triplicates).
ARTICLE ABSTRACT
The response to immune checkpoint inhibitors (ICI) often differs between genders in non–small cell lung cancer (NSCLC), but metanalyses results are controversial, and no clear mechanisms are defined. We aim at clarifying the molecular circuitries explaining the differential gender-related response to anti–PD-1/anti–PD-L1 agents in NSCLC.
We prospectively analyzed a cohort of patients with NSCLC treated with ICI as a first-line approach, and we identified the molecular mechanisms determining the differential efficacy of ICI in 29 NSCLC cell lines of both genders, recapitulating patients’ phenotype. We validated new immunotherapy strategies in mice bearing NSCLC patient-derived xenografts and human reconstituted immune system (“immune-PDXs”).
In patients, we found that estrogen receptor α (ERα) was a predictive factor of response to pembrolizumab, stronger than gender and PD-L1 levels, and was directly correlated with PD-L1 expression, particularly in female patients. ERα transcriptionally upregulated CD274/PD-L1 gene, more in females than in males. This axis was activated by 17-β-estradiol, autocrinely produced by intratumor aromatase, and by the EGFR-downstream effectors Akt and ERK1/2 that activated ERα. The efficacy of pembrolizumab in immune-PDXs was significantly improved by the aromatase inhibitor letrozole, which reduced PD-L1 and increased the percentage of antitumor CD8+T-lymphocytes, NK cells, and Vγ9Vδ2 T-lymphocytes, producing durable control and even tumor regression after continuous administration, with maximal benefit in 17-β-estradiol/ERα highfemale immune-xenografts.
Our work unveils that 17-β-estradiol/ERα status predicts the response to pembrolizumab in patients with NSCLC. Second, we propose aromatase inhibitors as new gender-tailored immune-adjuvants in NSCLC.
