Abstract 2163: Gender and estrogens as key factors in the response to immunotherapy in non small cell lung cancer
Authors: La Vecchia Sofia , Anobile Dario Pasquale , Tabbò Fabrizio , Salaroglio Iris C. , Kopecka Joanna , Primo Luca , Righi Luisella , Scagliotti Giorgio Vittorio , Novello Silvia , Corbet Cyril , Riganti Chiara 
Published: June 2022

Abstract
Gender is an important stratification and prognostic factor in oncology in the response to treatments, particularly to the immunotherapy. The anti-PD-1/PD-L1 immune-checkpoint inhibitors (Pembrolizumab, Nivolumab, Atezolizumab) have improved the prognosis of non-small cell lung cancer (NSCLC) patients in 20-35% cases, but with a lower efficacy in females. The different steroid hormones - estrogens, progesterone or androgens - present in both gender have often contrasting effects on the activity of the host immune system, partly explaining the differences observed. It is not known if metabolic features of cancer cells of male and female patients may impact on the immune system response and immunotherapy efficacy. We set up an analytical pipeline based on patient-derived samples, cell lines and humanized male and female mice bearing gender-matched NSCLC xenografts. NanoString analysis in a cohort of 42 NSCLC patients of both genders treated with Pembrolizumab, identified the estrogen receptor α (ERα)/ESR1 gene as one of the most significantly associated with the response to Pembrolizumab, particularly in female patients. A panel of 30 human NSCLC cell lines of female and male origin, that reproduced the ERα/gender association observed in clinical samples, the amount of ERα and 17-β-estradiol was directly related to the expression of PD-L1, suggesting a potential direct linkage. ERα transcriptionally up-regulated CD274/PD-L1 gene, with higher effects in females. EGFR downstream effectors Akt and ERK1/2, increased the active form phospho(Ser118)ERα, upregulating PD-L1.
Inhibiting the estrogen synthesis or switching off EGFR activity down-regulated PD-L1 levels. Consistently, the aromatase inhibitor letrozole increased the efficacy of Pembrolizumab in humanized NSCLC xenografts, by reducing tumor growth and tumor-associated PD-L1, increasing the infiltrating CD8+T-lymphocytes, NK cells and Vγ9Vδ2 anti-tumor T-lymphocytes. The benefit was maximal in 17-β-estradiol/ERα high female xenografts, intermediate in 17-β-estradiol/ERα medium female and male xenografts, minimal in 17-β-estradiol/ERα low male xenografts.
Additionally, an untargeted lipidome analysis revealed that letrozole decreased the saturated fatty acids (SFAs)/mono- or poly-unsaturated fatty acids (MUFAs-PUFAs) ratio, and the cholesterol/cholesterol esters ratio. These changes increased plasma-membrane fluidity, an event that in turns reduced the affinity between PD-L1 and PD-1. As further proof of concept, ω6- or ω3-PUFA treated cells, displayed an increased membrane fluidity and a change in lipid metabolism that affect the response to anti-PD-1/PD-L1 as letrozole did.
We propose a prototypical in vitro 3D spheroids culture gender-tailored platform that allows to investigate the metabolic circuitries causing such differences and to repurpose metabolic modifiers as novel immune-adjuvant agents in oncology.
Citation Format: Sofia La Vecchia, Dario Pasquale Anobile, Fabrizio Tabbò, Iris C. Salaroglio, Joanna Kopecka, Luca Primo, Luisella Righi, Giorgio Vittorio Scagliotti, Silvia Novello, Cyril Corbet, Chiara Riganti. Gender and estrogens as key factors in the response to immunotherapy in non small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2163.