15P - Verteporfin might potentiate the effects of anti-PD-1 therapy in melanoma-bearing mice model

Background

The feasibility of immune checkpoint inhibitors, such as anti-PD-1, remains low because of poor patient selection. We aimed to find predictive biomarkers of resistance to immune checkpoint inhibitors using publicly available transcriptomic and clinical data.

Methods

An online analysis platform (https://rocplot.com/immune) with 1,434 samples from distinct tumor types was set up. Genes overexpressed in non-responding patients were selected based on Mann-Whitney test, receiver operating characteristics (ROC) curve, and survival analysis using KM-plotter immune web platform. A clinically approved, druggable target was selected using a literature search. Cytotoxicity of the selected target was tested in vitro, then used in C57BL/6JRj mice to investigate combinational effects with anti-PD-1 immune checkpoint inhibitor.

Results

Yes-Associated Protein 1 (YAP1) was the best druggable target overexpressed in non-responding patients (ROC AUC=0.7, FC=1.8, P_ROC=7.5E-11) in the anti-PD-1 melanoma pre-treatment cohort (n=415). Patients with higher YAP1 expression showed worse progression-free survival (HR=2.51, P=1.2E-06, log-rank test) and overall survival (HR=2.15, P=1.2E-05). Verteporfin (VP), a YAP1 inhibitor, was chosen for combination therapy. We found that VP significantly decreased the viability of immunologically 'cold' melanoma cell lines B16-F10 and YUMM1.7 after 48 hours at concentrations of 0.1 μM (P=0.001) and 1 μM (P<0.001), respectively (one-way ANOVA). Compared to anti-PD-1 monotherapy (P=0.008, independent t-test) or IgG2a isotype control (P=0.021) groups, the combination of VP with anti-PD-1 demonstrated greater efficiency in YUMM1.7-inoculated mice. Neither VP nor anti-PD-1 exhibited significant tumor growth inhibition compared to the control (P>0.05, independent t-test). In the anti-PD-1 plus VP therapy group, CD3 (P=0.05), CD45 (P<0.05), CD68 (P=0.01), CD86 (P<0.05), and CD80 (P=0.01) had higher expression compared to control (one-way ANOVA).

Conclusions

A feasible immuno-oncology database was set up for the discovery of predictive biomarkers. A druggable target (YAP1) was chosen for in vitro and in vivo validation. YAP1 inhibitor Verteporfin exhibited higher efficacy in treating melanoma in mice.

Legal entity responsible for the study

The authors.

Funding

National Research, Development and Innovation Office (Hungary): PharmaLab (RRF-2.3.1-21-2022-00015), RRF-2.3.1-21-2022-00003, and 2022-1.1.1-KK-2022-00005. European Union's Horizon 2020 Programme: Grant agreement no. 739593. Hungarian Academy of Sciences: Momentum Research Grant (LP-2021-14). Ministry for Innovation and Technology (Hungary): New National Excellence Program (ÚNKP-23-4-I-SE-5) and KDP-2020 funding scheme (KDP-14-3/PALY-2021).

Disclosure

All authors have declared no conflicts of interest.