Discovery of 4-phenyl-1H-indazole derivatives as novel small-molecule inhibitors targeting the PD-1/PD-L1 interaction.

The inhibition of the programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway with small molecules is a promising approach for cancer immunotherapy. Herein, novel small molecules compounds bearing various scaffolds including thiophene, thiazole, tetrahydroquinoline, benzimidazole and indazole were designed, synthesized and evaluated for their inhibitory activity against the PD-1/PD-L1 interaction. Among them, compound Z13 exhibited the most potent activity with IC50 of 189.6 nM in the homogeneous time-resolved fluorescence (HTRF) binding assay. Surface plasmon resonance (SPR) assay demonstrated that Z13 bound to PD-L1 with high affinity (KD values of 231 nM and 311 nM for hPD-L1 and mPD-L1, respectively). In the HepG2/Jurkat T co-culture cell model, Z13 decreased the viability rate of HepG2 cells in a concentration-dependent manner. In addition, Z13 showed significant in vivo antitumor efficacy (TGI = 52.6 % at 40 mg/kg) without obvious toxicity in the B16-F10 melanoma model. Furthermore, flow cytometry analysis demonstrated that Z13 inhibited tumor growth in vivo by activating the tumor immune microenvironment. These findings indicate that Z13 is a promising PD-1/PD-L1 inhibitor deserving further investigation.

Use of patient-derived tumor organoid platform to predict the benefit of postoperative adjuvant chemotherapy for poor responders to neoadjuvant chemoradiotherapy in locally advanced rectal cancer.

Postoperative adjuvant chemotherapy (AC) for poor responders to neoadjuvant chemoradiotherapy (nCRT) remains debatable among patients with locally advanced rectal cancer (LARC), necessitating biomarkers to accurately predict the benefits of AC. This study aimed to develop a patient-derived tumor organoid (PDTO) platform to predict the benefit of AC in LARC patients showing poor nCRT response. PDTOs were established using irradiated rectal cancer specimens with poor nCRT responses, and their sensitivity to chemotherapy regimens was tested. The half-maximal inhibitory concentration (IC50) value for the PDTO drug test was defined based on the clinical outcomes, and the accuracy of the PDTO prognostic predictions was calculated. Predictive models were developed and validated using the PDTO drug test results. Between October 2018 and December 2021, 86 PDTOs were successfully constructed from 138 specimens (success rate 62.3%). The optimal IC50 cut-off value for the organoid drug test was 39.31 µmol/L, with a sensitivity of 84.75%, a specificity of 85.19%, and an accuracy of 84.88%. Multivariate Cox regression analysis revealed that the PDTO drug test was an independent predictor of prognosis. A nomogram based on the PDTO drug test was developed, showing good prognostic ability in predicting the 2-year and 3-year disease-free survivals (AUC of 0.826 [95% CI, 0.721-0.931] and 0.902 [95% CI, 0.823-0.982], respectively) and overall survivals (AUC of 0.859 [95% CI, 0.745-0.973] and 0.885 [95% CI, 0.792-0.978], respectively). The PDTO drug test can predict the benefit of postoperative AC in poor responders with LARC to nCRT.