126P - Effect of sequential antitumoral treatment with immune checkpoint blockade and tyrosine kinase inhibitors in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide and its incidence is steadily rising. Recently, immune-checkpoint inhibitors have revolutionized the management of HCC and combination of atezolizumab and bevacizumab has been shown to improve overall survival. We performed a molecular and cellular characterization of the tumour microenvironment that plays a crucial role in the development of HCC.

Methods

We performed a sequential treatment with anti-PD-L1 atezolizumab in combination with anti-VEGF bevacizumab for 6 days followed by tyrosine kinase inhibitor (TKI) lenvatinib for additional 6 days on HCC cell lines (HuH7 and SNU449) and then we measured the resulted effect by MTT assay for cell proliferation. After treatments we investigated tumour microenvironment (vimentin, cadherin) and immune markers (PD-L1, CTLA4 and cytokines) on HuH7 and SNU449 cells co-coltured with PBMCs (peripheral blood mononuclear cells) through RT-PCR.

Results

Combination of atezolizumab and bevacizumab followed by lenvatinib shows a reduction of cell growth, we observed a decrease in cell proliferation of 53.2 and 58.1 % for HuH7 and SNU449 respectively. This result is enhanced in cell co-coltures with PBMCs, in which cell viability is significantly reduced reaching value of 37.5 and 38.2 % for HuH7 and SNU449. We observed a decrease of PD-L1 and CTLA4 and a parallel increase of IFNγ, GRZb, IL-6 and IL1β, all cytokines able to create favourable microenvironment for inflammatory and immune response. The effect is accompanied by a functional change in favour of EMT blockade with increased cadherin and reduced vimentin expression (8.26- and 0.5-fold increase values, for cadherin and vimentin respectively, compared to untreated control) after sequential treatments.

Conclusions

Our work could provide good perspectives on predictability and sensitivity to new drug combination strategies in patients with HCC resistant to immune blockade. We aim to confirm the effect of the treatment also in ex vivo human spheroids and patients derived lymphocytes co-coltures, to verify the possible synergism of PD-L1 and VEGF inhibition on cytokine secretion profile.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.