S100A9+CD14+ monocytes contribute to anti-PD-1 immunotherapy resistance in advanced hepatocellular carcinoma by attenuating T cell-mediated antitumor function.

BACKGROUND: The paucity of reliable biomarkers for predicting immunotherapy efficacy in patients with advanced hepatocellular carcinoma (HCC) has emerged as a burgeoning concern with the expanding use of immunotherapy. This study endeavors to delve into the potential peripheral biomarkers capable of prognosticating efficacy in HCC patients who are poised to receive anti-PD-1 monotherapy within the phase III clinical trial, KEYNOTE394. Additionally, we sought to elucidate the underlying molecular mechanisms for resistance to immune checkpoint blockade (ICB) and propose innovative combination immunotherapy strategies for future clinical application. METHODS: Patient blood samples were collected for single-cell RNA sequencing to evaluate the immune cell signature before receiving ICB therapy. Subsequently, in vitro assays and in vivo murine model experiments were conducted to validate the mechanism that S100A9+CD14+ monocytes play a role in ICB resistance. RESULTS: Our study demonstrates a notable enrichment of S100A9+CD14+ monocytes in the peripheral blood of patients exhibiting suboptimal responses to anti-PD-1 therapy. Moreover, we identified the Mono_S100A9 signature as a predictive biomarker, indicative of reduced efficacy in immunotherapy and decreased survival benefits across various tumor types. Mechanistically, S100A9 activates PD-L1 transcription by directly binding to the CD274 (PD-L1) gene promoter, thereby suppressing T-cell proliferation and cytotoxicity via the PD-1/PD-L1 axis, consequently diminishing the therapeutic effectiveness of subsequent anti-PD-1 treatments. Furthermore, our in vivo studies revealed that inhibiting S100A9 can synergistically enhance the efficacy of anti-PD-1 drugs in the eradication of hepatocellular carcinoma. CONCLUSIONS: Our study underscores the significance of S100A9+CD14+ monocytes in predicting inadequate response to ICB treatment and provides insights into the monocyte cell-intrinsic mechanisms of resistance to ICB therapy. We also propose a combined therapeutic approach to enhance ICB efficacy by targeting S100A9.

Clinical Study of Glutamine Combined with Early Enteral Nutrition Support on Nutritional Status of Gastric Cancer Patients Undergoing Neoadjuvant Chemotherapy.

Objective: To explore the clinical study of glutamine combined with early enteral nutrition support on the nutritional status of gastric cancer patients undergoing neoadjuvant chemotherapy. Methods: Divided into control and observation groups, a control group received routine enteral nutrition, while the observation group received an additional 0.5 g/kg/d of glutamine. The researchers measured nutritional indicators, immunoglobulins, T lymphocyte subsets, and stress indexes such as fasting blood sugar and C-reactive protein throughout the study. Results: Before nutritional support, there was no significant difference in the HGB, TP, and ALB levels. During nutritional support, however, the observation group began registering significantly higher levels of HGB, TP, and ALB, suggesting that glutamine intervention can improve the nutritional status of patients. Throughout the study, the CD4+ level showed a consistent increase in the observation group. The levels of IgA and IgG in the observation group also grew significantly higher. Both groups had higher blood glucose levels before nutritional support. However, on day 8 and day 15, the levels decreased. The observation group had significantly lower fasting blood glucose (FBG) levels than the control group. By day 15, the FBG levels in the observation group were close to normal. The CRP level showed a consistent decrease in the observation group compared to the control group on day 8 and day 15. Glutamine intervention appears to improve the stress capacity of gastric cancer patients undergoing neoadjuvant chemotherapy. Overall, the findings suggest that glutamine intervention in enteral nutrition can significantly improve immune function, nutritional status, and stress capacity in gastric cancer patients undergoing neoadjuvant chemotherapy and appears to be more effective than conventional enteral nutrition. Conclusion: The combination of glutamine and early enteral nutrition support can significantly improve gastric cancer patients undergoing neoadjuvant chemotherapy's nutritional status and immune function levels. It is a safe and reliable enteral nutrition support method worthy of clinical promotion.