Abstract 1294: Platinum-based chemotherapy immunomodulatory effects and immunotherapy association in upper tract urothelial carcinomas
Authors: Fauvre Alexandra , Vie Nadia , Robin Mathilde , Taffoni Clara , Laguette Nadine , Faget Julien , Gros Laurent , Garcin Aurélie , Gongora Celine , Houede Nadine 
Published: June 2022

Abstract
Upper Tract Urothelial Carcinomas (UTUC) are extremely aggressive tumors of ureter or renal pelvis. UTUC present less tumor mutational burden and low tumor immune infiltrate compared to bladder cancer. Despite this they are treated with the same protocol than bladder cancer with more than 50% of relapses justifying the need of new therapeutic options. To improve patient care, we suggest stimulating the immune system by platinum-based chemotherapies (Cisplatin-Gemcitabine (CisGem) or Carboplatin-Gemcitabine (CarboGem)) in order to potentiate the effect of an anti-PD-L1, the Durvalumab. We launched a phase II clinical trial called “iNDUCT” which studies these combinations in UTUC patients. In parallel, we conduct an in vitro project that aims to determine if chemotherapies could transform cold tumor into a hot tumor, and if so by which mechanisms? Using UTUC cell lines (UM-UC-14,UCC03,UCC17,UCC14,UCC47) we have evaluated the cytotoxicity effects of the chemotherapies combinations in 2D and 3D cell cultures. We have assessed their potential (i) to induce DNA damage using image cytometry, (ii) to induce PD-L1 expression using flow cytometry, (iii) to induce immune cell death using ELISA kits, (iv) to activate the cGAS/STING pathway using qPCR and Western-Blot, and finally (v) to attract immune cells by using heterotypic spheroids model (tumoral cells+PBMCs).Our results demonstrate that CisGem and CarboGem present synergistic effects in UTUC spheroid cultures. These treatments also induce DNA damage pathway demonstrated by an increase of γH2AX, P-ATM, P-CHK1 and P-CHK2 positive cells. We found an increase of PD-L1 membrane expression after treatment in UTUC cell lines. RNA Seq analyses indicates that the major pathways upregulated by these combinations are inflammatory pathways (TNF-α signaling via NFkB, interferon alpha response, inflammatory response, interferon gamma response). We could observe an immune cell death induction demonstrated by an increase of ATP and HMGB1 release and calreticulin translocation. We showed cGAS/STING pathway activation as evidenced by an increase of P-IRF3 and interferon stimulated genes (ISGs) expression. We demonstrated an inhibition of the ISGs induction after treatment by our chemotherapies when cells are treated with an ATM inhibitor or in UMUC-14 deleted for STING. And we finally showed that CisGem and CarboGem can increase immune infiltration in the heterotypic tumor spheroids.
These results indicate that the combination of platinum salts + gemcitabine induces inflammatory pathways via a non-canonical STING pathway dependent on ATM activation in UTUC model. Furthermore, these combination induce an upregulation of PD-L1 expression and allow immune cells attraction at the tumor. All these data support that a combination CisGem or CarboGem with an anti-PD-L1 will be efficient for UTUC patients.
Citation Format: Alexandra Fauvre, Nadia Vie, Mathilde Robin, Clara Taffoni, Nadine Laguette, Julien Faget, Laurent Gros, Aurélie Garcin, Celine Gongora, Nadine Houede. Platinum-based chemotherapy immunomodulatory effects and immunotherapy association in upper tract urothelial carcinomas [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 1294.