Near-infrared II fluorescence imaging of PD-L1 and VEGF for assessing and early prediction of “T+A” therapeutic responsiveness in hepatocellular carcinoma

The combination of atezolizumab (T, anti-PD-L1) and bevacizumab (A, anti-VEGF) (“T+A”) are recommended as first line treatment in patients with unresectable hepatocellular carcinoma (HCC). However, there is a lack of reliable methods to accurately screen beneficiary populations and predict therapeutic outcomes for “T+A” treatment. In this study, we developed two antibody-labelled quantum dot (QD)-based nanoprobes with non-overlapping near-infrared II (NIR-II) fluorescence for simultaneous in vivo imaging of VEGF and PD-L1 levels within tumors. These nanoprobes utilized NIR-II QDs (emission: ∼950 nm and 1550 nm) as cores, while coating with 4-Arm-PEG-NH 2 as a linker to accomplish highly efficient conjugation of anti-VEGF or anti-PD-L1 antibodies via amide condensation. By using tumor-bearing mouse model, we confirmed positive correlation between the in vivo fluorescence signal and the corresponding protein expression level of tumors as determined by immunohistochemistry. Importantly, our results demonstrated that high fluorescence signal of VEGF and PD-L1 levels within tumors indicated more immunosuppressive microenvironment and was associated with faster tumor progression. At meanwhile, fluorescent imaging for VEGF and PD-L1 levels before treatment could predict the endpoint of therapeutic response to “T+A” regimen. Indeed, high fluorescence signal suggested a better therapeutic response versus that with low fluorescence. Overall, our findings established an in vivo dual-targets fluorescent molecular imaging technique as a promising clinical decision-making tool that can predict response to “T+A” regimen in a minimally invasive manner prior to treatment initiation, therapy enabling personalized therapy selection for patients with advanced HCC.