Colorectal cancer (CRC) is the most common malignant tumor type and has become resistant to 5-fluorouracil (5-FU) in recent decades, which is one of the most popular therapies. Recently, microRNA (miRNA or miR) has been investigated as a potential therapeutic strategy for CRC. However, there has been little investigation of the underlying mechanism of the association between expression of miRNA and chemosensitivity. The present study aimed to investigate the effect of miR-1260b inhibitor on CRC cells, and their chemosensitivity to 5-FU, by treating them with the miR-1260b inhibitor. miR-1260b inhibitor was demonstrated to significantly promote the proliferation and invasion of the CRC cell line, HCT116, and to increase the apoptotic rate. Furthermore, it was validated that programmed cell death 4 (PDCD4) was a direct target of miR-1260b inhibitor in CRC with bioinformatics tools and a luciferase assay. Western blot analysis revealed that miR-1260b inhibitor could significantly decrease PDCD4 expression, and downregulate the expression of phosphorylated-Akt (p-Akt) and phosphorylated-extracellular-signal-regulated kinase (p-ERK). In conclusion, it was confirmed that the anti-tumor effect of the miR-1260b inhibitor was conducted by blocking the phosphorylated 3-kinase/Akt pathway as dysregulated protein expression induced by miR-1260b inhibitor was rescued by insulin-like growth factor. Notably, miR-1260b inhibitor could significantly enhanced the chemoresponse of HCT116 cells to 5-FU via reduced proliferation, increased apoptosis, and downregulation of PDCD4, p-Akt and p-ERK protein expression. In summary, the present study may provide a novel direction for future clinical therapy to enhance the chemosensitivity of tumor cells.

In recent years, immunotherapy has been widely used to treat patients with malignant tumors. While immune checkpoint inhibitors (ICIs) significantly improve the prognosis of cancer patients, the incidence of immune-related adverse events (irAEs) is increasing. Not only can irAEs accumulate in multiple organ systems throughout the body, but rare adverse reactions may also occur continuously. In severe cases, irAEs can be life-threatening or even lead to death. Therefore, the early identification, diagnosis and treatment of irAEs are very important. Early identification of patients with high-risk irAEs as well as the reduction or avoidance of severe irAEs have important clinical significance. This article will review the research progress of early predictive biomarkers and risk factors for the occurrence of irAEs and propose potential future directions for follow-up research and clinical applications.

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e16084 Background: The introduction of immune checkpoint inhibitors (ICIs) after chemotherapy and targeted therapy has altered the treatment pattern of esophageal squamous cell carcinoma (ESCC). However, using ICIs alone results in a poor response rate. Fortunately, fundamental research indicates that chemotherapy might trigger immunogenic death of tumor cells by releasing tumor antigens, hence eliminating immune system repression of tumor cells. On this basis, a number of clinical studies, including KEYNOTE-590, CheckmMate-648, ORIENT-15, and ESCORT-1st, on the first-line treatment of ESCC with ICIs coupled with chemotherapy, including fluorouracil or taxol and platinum (PF or TP), were conducted and yielded favorable results. However, the advantage of safety and effectiveness of ICIs combination with PF and TP in Chinese ESCC remains unknown. Furthermore, since the southeast part of Shanxi province has a high prevalence of esophageal cancer, the geographical features of ESCC patients will be examined. Methods: Camrelizumab was maintained after 6 cycles of camrelizumab in combination with PF or TP chemotherapy. From May 2020 to February 2022, our study has included 40 locally progressed and advanced ESCC patients. Camrelizumab was administered in combination with PF to 11 patients and TP to 29 patients. Every 6 weeks, efficacy was examined using RECIST 1.1, and 33 patients were evaluated. This research was registered with the Chinese Clinical Trials Registry (ChiCTR2000037942). Results: The median treatment time was 5.8m. 82.5% (33/40) patients were availably evaluated. The objective response rate (ORR) was 72.7% (24/33) and the disease control rate (DCR) was 97.0% (32/33). There is no statistically significant difference in ORR ( p=0.1779) and DCR ( p=0.1005) between PF and TP (55.6% vs 79.2%, 88.9% vs 100%) regimens. At this moment, mPFS has not been achieved. The most common adverse events (AEs) were anemia (22.5%, 9/40), lymphocytopenia (15%, 6/40), neutropenia(15%, 6/40), reactive cutaneous capillary endothelial proliferation (RCCEP) (12.5%, 5/40) and fatigue (7.5%, 3/40). Thrombocytopenia (2.5%, 1/40), neutropenia (2.5%, 1/40) and leukopenia (2.5%, 1/40) were the most common grade 3 or 4 toxicities The most frequently reported immune-related AEs were RCCEP (12.5%, 5/40) and hypothyroidism (7.5%, 3/40). There were no new significant adverse events. Conclusions: Camrelizumab in combination with chemotherapy is a promising regimen with good tolerability in the first-line treatment of ESCC. Compared with FP, TP had more therapeutic advantages, But the result is a stage summary, and further observation is needed. Clinical trial information: ChiCTR2000037942. [Table: see text]