The efficacy and safety of sintilimab combined with chemotherapy as the first-line treatment for metastatic esophageal squamous cell carcinoma.

Immunotherapy is a new treatment option for patients with esophageal squamous cell carcinoma (ESCC). However, no study has investigated the efficacy and safety of sintilimab combined with nanoparticle albumin-bound paclitaxel (Nab-PTX) and platinum as first-line treatment for metastatic ESCC. In this retrospective study, eligible patients with metastatic ESCC were administered sintilimab plus Nab-PTX, cisplatin, or nedaplatin for up to 4 to 6 cycles. Subsequently, patients without progressive disease (PD) continued to receive sintilimab every 3 weeks as maintenance treatment until unacceptable toxicity, PD, withdrawal of consent, or for up to 2 years. The primary endpoint was the objective response rate (ORR) and the secondary endpoints were progression-free survival (PFS), overall survival (OS), disease control rate (DCR), and safety. A total of 22 patients diagnosed with metastatic ESCC were enrolled, 1 patient reached a complete response (CR), 15 patients achieved a partial response (PR), 4 patients had stable disease, and 2 had PD. The ORR was 72.7% (16/22) and the DCR was 90.9% (20/22). The time to response was 1.9 months (95% confidence interval [CI]:1.7-2.2 months). The median PFS was 8.9 months (95% CI, 7.1-10.7 months), and the median OS was 19.0 months. Exploratory biomarker analysis revealed that lactic dehydrogenase (LDH) was a potential marker for OS, and patients with high LDH levels had shorter mOS (13.0 months, 95% CI:7.5-18.5 months). Treatment-related adverse events (AEs) occurred in 21 patients (95.5%), most of which were grade 1 or 2. No treatment-related deaths occurred in this study. The results of this study suggested that sintilimab combined with Nab-PTX and platinum in patients with metastatic ESCC had a significantly high ORR and encouraging mPFS and mOS. LDH was a potential marker for OS, and the safety profile was manageable.

Tax is involved in up-regulation of HMGB1 expression levels by interaction with C/EBP.

The high mobility group box 1 (HMGB1) protein is a multifunctional cytokine-like molecule that plays an important role in the pathogenesis of tumors. In this study, real-time polymerase chain reactions and Western blot assays indicated that HMGB1 transcriptional activity and protein level are increased in Tax+-T cells (TaxP). To clarify the mechanisms, a series of HMGB1 deletion reporter plasmids (pHLuc1 to pHLuc6) were transfected into Tax--T cells (TaxN, Jurkat) and Tax+-T cells (TaxP). We found that promoter activity in Tax+-T cells to be higher than that in Tax--T cells, indicating a significant increase in pHLuc6. Bay11-7082 (NF-κB inhibitor) treatment did not block the enhancing effect. Chromatin immunoprecipitation assays revealed that Tax was retained on a HMGB1 promoter fragment encompassing -1163 to -975. Bioinformatics analysis showed six characteristic cis-elements for CdxA, AP-1, AML-1a, USF, v-Myb, and C/EBP in the fragment in question. Mutation of cis- elements for C/EBP reduced significant HMGB1 promoter activity induced by Tax. These findings indicate that Tax enhances the expression of HMGB1 gene at the transcriptional level, possibly by interacting with C/EBP.