Background The standard neoadjuvant treatments in patients with esophageal squamous cell carcinoma (ESCC) still have either poor safety or efficacy. Better therapies are needed in China. Methods This was an open-label, single-arm, phase 2 trial. Patients with potentially resectable ESCC (cT1b-3, Nany, M0 or T4a, N0-1, or M0) received preoperative intravenous sintilimab plus triplet chemotherapy (liposomal paclitaxel, cisplatin, and S-1) every 3 weeks for two cycles. The primary endpoints were safety and surgical feasibility; the secondary endpoint was major pathological response (MPR) rate. Genomic biomarkers (genetic mutations, tumor mutational burden (TMB), circulating tumor DNA status and immune microenvironment) in baseline tumor samples were investigated. Results All 30 patients completed two cycles of neoadjuvant treatment and underwent surgical resection. Grade 3–4 treatment-related adverse events (TRAEs) occurred in 36.7% (11/30) of patients. The most frequent TRAEs were decreased white cell count (76.7%), anemia (76.7%), and decreased neutrophil count (73.3%). All TRAEs were hematological toxicities; none caused ≥30 days surgical delay. The MPR and pathological complete response (pCR) rates were 50.0% (15/30; 95% CI 33.2 to 66.9) and 20.0% (6/30; 95% CI 9.5 to 37.3), respectively. Patients with higher TMB and more clonal mutations were more likely to respond. ERBB2 alterations and ctDNA high-releaser status have a negative correlation with neoadjuvant ICI response. No significant difference was observed between therapeutic response and tumor immune microenvironment. Conclusions Neoadjuvant sintilimab plus platinum-based triplet chemotherapy appeared safe and feasible, did not delay surgery and induced a pCR rate of 20.0% in patients with potentially resectable ESCC. Trial registration number NCT03946969.

Resistance remains an obstacle to anti-programmed cell death protein 1 (PD-1) therapy in human cancer. One critical resistance mechanism is the lack of T cell chemotaxis in the tumor microenvironment (TME). CXCL10-CXCR3 signaling is required for T cell tumor infiltration and tumor immunotherapy. Oncolytic viruses (OVs), including oncolytic adenoviruses (AdVs), induce effective T cell immunity and tumor infiltration. Thus, arming OV with CXCL10 would be an attractive strategy to overcome resistance to anti-PD1 therapy. Here, we successfully constructed a novel recombinant oncolytic adenovirus encoding murine CXCL10, named Adv-CXCL10. Through intratumoural injection, the continuous expression of the functional chemokine CXCL10 in the TME is realized to recruit more CXCR3⁺ T cells into the TME to kill tumor cells, and the recombinant adenovirus shows great power to ‘fire up’ the TME and enhance the antitumour efficiency of PD-1 antibodies.

As a cytoplasmic sensor of double-stranded DNA (dsDNA), the cyclic GMP-AMP synthase–stimulator of IFN genes (STING) pathway plays an important role in antitumor immunity. In this study, we investigated the effect of Src homology-2 domain-containing protein tyrosine phosphatase-2 (SHP2) on tumor cell–intrinsic STING pathway activity and DNA repair in colon cancer. SHP2 interacted with and dephosphorylated PARP1 after DNA damage. PARP1 inhibition by SHP2 resulted in reduced DNA repair and accumulation of dsDNA in cells, thus promoting hyperactivation of the STING pathway. The SHP2 agonist lovastatin was able to enhance SHP2 activity and promote STING pathway activation. Moreover, lovastatin significantly enhanced the efficacy of chemotherapy in colon cancer models, in part via STING pathway-mediated antitumor immunity. These findings suggest that SHP2 exacerbates STING pathway activation by restricting PARP1-mediated DNA repair in tumor cells, providing a basis for the combined use of lovastatin and chemotherapy in the treatment of colon cancer. Significance: Dephosphorylation of PARP1 by SHP2 simultaneously suppresses DNA repair and enhances STING pathway-mediated antitumor immunity, highlighting SHP2 activation as a potential therapeutic approach in colon cancer.

Identification of effective therapies for colorectal cancer (CRC) remains an urgent medical need, especially for the microsatellite-stable (MSS) phenotype. In the current study, a combination of fruquintinib plus anti–PD-1 for MSS CRC therapy was investigated. First, a case of advanced MSS CRC was reported. After failure of multiline therapy, the patient finally achieved rapid response after receiving fruquintinib plus anti–PD-1 treatment. Then the effect of fruquintinib plus anti–PD-1 was verified using a murine syngeneic model of CT26 cells (MSS). The results showed that cotreatment significantly inhibited tumor growth and promote survival time for tumor-bearing mice compared with the single drug alone. In addition, fruquintinib/anti–PD-1 cotreatment decreased angiogenesis, enhanced normalization of the vascular structure, and alleviated tumor hypoxia. Moreover, the combination therapy reprogrammed the immune microenvironment by enhancing chemotactic factor release, increasing CD8⁺ T cell infiltration and activation, decreasing ration of regulatory T cells, and promoting M1/M2 ratio of macrophage. Finally, the enhanced antitumor effect of fruquintinib/anti–PD-1 cotreatment was significantly reversed in CD8 knockout mice compared with that in the wild-type mice. Our study indicated that combination of fruquintinib and anti–PD-1 could synergistically suppress CRC progression and altered the tumor microenvironment in favor of antitumor immune responses. Key Points An MSS CRC patient responded rapidly to fruquintinib plus anti–PD-1 therapy. Fruquintinib plus anti–PD-1 treatment significantly inhibited tumor growth in mice. Fruquintinib plus anti–PD-1 treatment led to an antitumor tumor microenvironment.