Development of small molecule drugs targeting immune checkpoints

Immune checkpoint inhibitors(ICIs)are used to relieve and refuel anti-tumor immunity by blocking the interaction,transcription,and translation of co-inhibitory immune checkpoints or degrading co-inhibitory immune checkpoints.Thousands of small molecule drugs or biological materials,especially antibody-based ICIs,are actively being studied and antibodies are currently widely used.Limitations,such as anti-tumor efficacy,poor membrane permeability,and unneglected tolerance issues of antibody-based ICIs,remain evident but are thought to be overcome by small molecule drugs.Recent structural studies have broadened the scope of candidate immune checkpoint molecules,as well as innovative chemical inhibitors.By way of comparison,small molecule drug-based ICIs represent superior oral bioavailability and favorable pharmacokinetic features.Several ongoing clinical trials are exploring the synergetic effect of ICIs and other therapeutic strategies based on multiple ICI functions,including immune regulation,anti-angiogenesis,and cell cycle regulation.In this review we summarized the current progression of small molecule ICIs and the mechanism underlying immune checkpoint proteins,which will lay the foundation for further exploration.

Understanding the function and dysfunction of the immune system in lung cancer: the role of immune checkpoints

Survival rates for metastatic lung cancer, including non-small cell lung cancer （NSCLC） and small cell lung cancer （SCLC）, are poor with S-year survivals of less than 5%. The immune system has an intricate and complex relationship with tumorigenesis; a groundswell of research on the immune system is leading to greater understanding of how cancer progresses and presenting new ways to halt disease progress. Due to the extraordinary power of the immune system-- with its capacity for memory, exquisite specificity and central and universal role in human biology--immunotherapy has the potential to achieve complete, long-lasting remissions and cures, with few side effects for any cancer patient, regardless of cancer type. As a result, a range of cancer therapies are under development that work by turning our own immune cells against tumors. However deeper understanding of the complexity of immunomodulation by tumors is key to the development of effective immunotherapies, especially in lung cancer.

Current state and future of co-inhibitory immune checkpoints for the treatment of glioblastoma

In the interaction between a tumor and the immune system,immune checkpoints play an important role,and in tumor immune escape,co-inhibitory immune checkpoints are important.Immune checkpoint inhibitors(ICIs)can enhance the immune system's killing effect on tumors.To date,impressive progress has been made in a variety of tumor treatments;PD1/PDL1 and CTLA4 inhibitors have been approved for clinical use in some tumors.However,glioblastoma(GBM)still lacks an effective treatment.Recently,a phase III clinical trial using nivolumab to treat recurrent GBM showed no significant improvement in overall survival compared to bevacizumab.Therefore,the use of immune checkpoints in the treatment of GBM still faces many challenges.First,to clarify the mechanism of action,how different immune checkpoints play roles in tumor escape needs to be determined;which biomarkers predict a benefit from ICIs treatment and the therapeutic implications for GBM based on experiences in other tumors also need to be determined.Second,to optimize combination therapies,how different types of immune checkpoints are selected for combined application and whether combinations with targeted agents or other immunotherapies exhibit increased efficacy need to be addressed.All of these concerns require extensive basic research and clinical trials.In this study,we reviewed existing knowledge with respect to the issues mentioned above and the progress made in treatments,summarized the state of ICIs in preclinical studies and clinical trials involving GBM,and speculated on the therapeutic prospects of ICIs in the treatment of GBM.

Cytokine release syndrome induced by anti-programmed death-1 treatment in a psoriasis patient:A dark side of immune checkpoint inhibitors

In recent years,cancer immunotherapy has introduced novel treatments,such as monoclonal antibodies,which have facilitated targeted therapies against tumor cells.Programmed death-1(PD-1)is an immune checkpoint expressed in T cells that regulates the immune system’s activity to prevent over-activation and tissue damage caused by inflammation.However,PD-1 is also expressed in tumor cells and functions as an immune evasion mechanism,making it a therapeutic target to enhance the immune response and eliminate tumor cells.Consequently,immune checkpoint inhibitors(ICIs)have emerged as an option for certain tumor types.Nevertheless,blocking immune checkpoints can lead to immune-related adverse events(irAEs),such as psoriasis and cytokine release syndrome(CRS),as exemp-lified in the clinical case presented by Zhou et al involving a patient with adva-nced gastric cancer who received sintilimab,a monoclonal antibody targeting PD-1.Subsequently,the patient experienced exacerbation of psoriasis and CRS.The objective of this editorial article is to elucidate potential immunologic mechanisms that may contribute to the development of CRS and psoriasis in patients receiving ICIs.It is crucial to acknowledge that while ICIs offer superior safety and efficacy compared to conventional therapies,they can also manifest irAEs affecting the skin,gastrointestinal tract,or respiratory system.In severe cases,these irAEs can lead to life-threatening complications such as circulatory shock or multiorgan failure.Consequently,it is recommended that patients receiving ICIs undergo regular monitoring to identify and manage these adverse events effectively.

Prognostic characterization of copper death-related immune checkpoint genes and analysis of immunologic and pharmacologic therapy in bladder cancer

Objective:Copper death-induced tumor cell death and immune checkpoint blockade therapy are highly selective.Combining their advantages and understanding their characteristics in bladder cancer is very important for the development of new targeted therapy.The identification of bladder cancer by screening the characteristic genes of copper death-related immune checkpoints provide a theoretical basis for the selection of adjuvant treatment options and the application of new targets.Methods:The expression samples of normal bladder tissue and bladder cancer were obtained from TCGA and GEO databases,and 13 cop-per death genes and 79 immune checkpoint genes were extracted from previous studies.The mRNA expression of prognostic genes was verified by qPCR.The copper death-related immune checkpoint genes were screened by correlation analysis to construct a prognostic model,and the differences in the efficacy of immunotherapy and chemotherapy between the high-risk group and the low-risk group were evaluated.Results:A prognostic model consisting of BTNL9,CD160,TNFRSF14 and TNFRSF18 was constructed.Its reliable predictive ability was proved in both databases,and qPCR showed that the expression levels of the four genes were significantly different between the normal group and the cancer cell group.The effect of immunotherapy in the lowrisk group was better than that in the high-risk group.Patients in the high-risk group had better chemotherapy efficacy.Conclusion:The copper death-related immune checkpoint gene model can accurately predict the prognosis of patients.Drug and immune analysis provide a basis for clinical treatment,and the discovery of potential targets provides a new solution for clinical decision-making.

Pembrolizumab autoimmune related diabetes:Moving forward,keep learning

Immune checkpoint inhibitors(and more specifically programmed cell death 1/programmed cell death ligand 1 inhibitors as Pembrolizumab)initiated a revolution in the field of melanoma and have now expanded to several tumor subtypes and in increasingly broader clinical contexts,including the adjuvant and neoadjuvant setting,with potentially curable patients and prolonged survival.The side effects related to these drugs include a wide spectrum of manifestations,with endocrinological adverse events being some of the most frequent.Pembrolizumab-induced type 1 diabetes mellitus is an infrequent but potentially serious and not clearly reversible side effect that possesses characteristic clinical features and has high morbidity and mortality,with a chronic impact on quality of life.The etiopathogenesis of this phenomenom needs to be further investigated and a collaborative effort through the involvement of oncologists and other medical specialists is necessary for the correct identification and management of patients at risk.

Myeloid immunosuppression and immune checkpoints in the tumor microenvironment

Tumor-promoting inflammation and the avoidance of immune destruction are hallmarks of cancer.While innate immune cells,such as neutrophils,monocytes,and macrophages,are critical mediators for sterile and nonsterile inflammation,persistent inflammation,such as that which occurs in cancer,is known to disturb normal myelopoiesis.This disturbance leads to the generation of immunosuppressive myeloid cells,such as myeloid-derived suppressor cells(MDSCs)and tumor-associated macrophages(TAMs).Due to their potent suppressive activities against effector lymphocytes and their abundance in the tumor microenvironment,immunosuppressive myeloid cells act as a major barrier to cancer immunotherapy.Indeed,various therapeutic approaches directed toward immunosuppressive myeloid cells are actively being tested in preclinical and clinical studies.These include antiinflammatory agents,therapeutic blockade of the mobilization and survival of myeloid cells,and immunostimulatory adjuvants.More recently,immune checkpoint molecules expressed on tumor-infiltrating myeloid cells have emerged as potential therapeutic targets to redirect these cells to eliminate tumor cells.In this review,we discuss the complex crosstalk between cancer-related inflammation and immunosuppressive myeloid cells and possible therapeutic strategies to harness antitumor immune responses.

Tumor immune checkpoints and their associated inhibitors

Immunological evasion is one of the defining characteristics of cancers,as the immune modification of an immune checkpoint(IC)confers immune evasion capabilities to tumor cells.Multiple ICs,such as programmed cell death protein-1(PD-1)and cytotoxic T-lymphocyte-associated antigen-4(CTLA-4),can bind to their respective receptors and reduce tumor immunity in a variety of ways,including blocking immune cell activation signals.IC blockade(ICB)therapies targeting these checkpoint molecules have demonstrated significant clinical benefits.This is because antibody-based IC inhibitors and a variety of specific small molecule inhibitors can inhibit key oncogenic signaling pathways and induce durable tumor remission in patients with a variety of cancers.Deciphering the roles and regulatory mechanisms of these IC molecules will provide crucial theoretical guidance for clinical treatment.In this review,we summarize the current knowledge on the functional and regulatory mechanisms of these IC molecules at multiple levels,including epigenetic regulation,transcriptional regulation,and post-translational modifications.In addition,we provide a summary of the medications targeting various nodes in the regulatory pathway,and highlight the potential of newly identified IC molecules,focusing on their potential implications for cancer diagnostics and immunotherapy.

Immune checkpoints in targetedi-mmunotherapy of pancreatic cancer:New hope for clinical development

Immunotherapy has been recently considered as a promising alternative for cancer treatment.Indeed,targeting of immune checkpoint(ICP)strategies have shown significant success in human malignancies.However,despite remarkable success of cancer immunotherapy in pancreatic cancer(PCa),many of the developed immunotherapy methods show poor therapeutic outcomes in PCa with no or few effective treatment options thus far.In this process,immunosuppression in the tumor microenvironment(TME)is found to be the main obstacle to the effectiveness of antitumor immune response induced by an immunotherapy method.In this paper,the latest findings on the ICPs,which mediate immunosuppression in the TME have been reviewed.In addition,different approaches for targeting ICPs in the TME of PCa have been discussed.This review has also synopsized the cutting-edge advances in the latest studies to clinical applications of ICP-targeted therapy in PCa.

Targeting immune checkpoints:how to use natural killer cells for fighting against solid tumors

Natural killer(NK)cells are unique innate immune cells that mediate antiviral and anti-tumor responses.Thus,they might hold great potential for cancer immunotherapy.NK cell adoptive immunotherapy in humans has shown modest efficacy.In particular,it has failed to demonstrate therapeutic efficiency in the treatment of solid tumors,possibly due in part to the immunosuppressive tumor microenvironment(TME),which reduces NK cell immunotherapy’s efficiencies.It is known that immune checkpoints play a prominent role in creating an immunosuppressive TME,leading to NK cell exhaustion and tumor immune escape.Therefore,NK cells must be reversed from their dysfunctional status and increased in their effector roles in order to improve the efficiency of cancer immunotherapy.Blockade of immune checkpoints can not only rescue NK cells from exhaustion but also augment their robust anti-tumor activity.In this review,we discussed immune checkpoint blockade strategies with a focus on chimeric antigen receptor(CAR)-NK cells to redirect NK cells to cancer cells in the treatment of solid tumors.

The combination of novel immune checkpoints HHLA2 and ICOSLG:A new system to predict survival and immune features in esophageal squamous cell carcinoma

Studies on immune checkpoint inhibitors targeting B7-CD28 family pathways in esophageal squamous cell carcinoma(ESCC)have shown promising results.However,a comprehensive understanding of B7-CD28 family members in ESCC is still limited.This study aimed to construct a novel B7-CD28 family-based prognosis system to predict survival in patients with ESCC.We collected 179 cases from our previously published microarray data and 86 cases with qPCR data.Specifically,119 microarray data(GSE53624)were used as a training set,whereas the remaining 60 microarray data(GSE53622),all 179 microarray data(GSE53625)and an independent cohort with 86 qPCR data were used for validation.The underlying mechanism and immune landscape of the system were also explored using bioinformatics and immunofluorescence.We examined 13 well-defined B7-CD28 family members and identified 2 genes(ICSOLG and HHLA2)with the greatest prognostic value.A system based on the combination HHLA2 and ICOSLG(B7-CD28 signature)was constructed to distinguish patients as high-or low-risk of an unfavorable outcome,which was further confirmed as an independent prognostic factor.As expected,the signature was well validated in the entire cohort and in the independent cohort,as well as in different clinical subgroups.The signature was found to be closely related to immune-specific biological processes and pathways.Additionally,high-risk group samples demonstrated high infiltration of Tregs and fibroblasts and distinctive immune checkpoint panels.Collectively,we built the first,practical B7-CD28 signature for ESCC that could independently identify high-risk patients.Such information may help inform immunotherapy-based treatment decisions for patients with ESCC.

Immune checkpoint inhibitor-associated gastritis:Patterns and management

Immune checkpoint inhibitors(ICIs)are widely used due to their effectiveness in treating various tumors.Immune-related adverse events(irAEs)are defined as adverse effects resulting from ICI treatment.Gastrointestinal irAEs are a common type of irAEs characterized by intestinal side effects,such as diarrhea and colitis,which may lead to the cessation of ICIs.Although irAE gastritis is rarely reported,it may lead to serious complications such as gastrorrhagia.Furthermore,irAE gastritis is often difficult to identify early due to its diverse symptoms.Although steroid hormones and immunosuppressants are commonly used to reverse irAEs,the best regimen and dosage for irAE gastritis remains uncertain.In addition,the risk of recurrence of irAE gastritis after the reuse of ICIs should be considered.In this editorial,strategies such as early identification,pathological diagnosis,mana-gement interventions,and immunotherapy rechallenge are discussed to enable clinicians to better manage irAE gastritis and improve the prognosis of these patients.

Molecular insights into clinical trials for immune checkpoint inhibitors in colorectal cancer:Unravelling challenges and future directions

Colorectal cancer(CRC)is a complex disease with diverse etiologies and clinical outcomes.Despite considerable progress in development of CRC therapeutics,challenges remain regarding the diagnosis and management of advanced stage metastatic CRC(mCRC).In particular,the five-year survival rate is very low since mCRC is currently rarely curable.Over the past decade,cancer treatment has significantly improved with the introduction of cancer immunotherapies,specifically immune checkpoint inhibitors.Therapies aimed at blocking immune checkpoints such as PD-1,PD-L1,and CTLA-4 target inhibitory pathways of the immune system,and thereby enhance anti-tumor immunity.These therapies thus have shown promising results in many clinical trials alone or in combination.The efficacy and safety of immunotherapy,either alone or in combination with CRC,have been investigated in several clinical trials.Clinical trials,including KEYNOTE-164 and CheckMate 142,have led to Food and Drug Administration approval of the PD-1 inhibitors pembrolizumab and nivolumab,respectively,for the treatment of patients with unresectable or metastatic microsatellite instability-high or deficient mismatch repair CRC.Unfortunately,these drugs benefit only a small percentage of patients,with the benefits of immunotherapy remaining elusive for the vast majority of CRC patients.To this end,primary and secondary resistance to immunotherapy remains a significant issue,and further research is necessary to optimize the use of immunotherapy in CRC and identify biomarkers to predict the response.This review provides a comprehensive overview of the clinical trials involving immune checkpoint inhibitors in CRC.The underlying rationale,challenges faced,and potential future steps to improve the prognosis and enhance the likelihood of successful trials in this field are discussed.

Hepatocellular carcinoma immune microenvironment and check point inhibitors-current status

Hepatocellular carcinoma(HCC)is the most common primary tumor of the liver and has a high mortality rate.The Barcelona Clinic Liver Cancer staging system in addition to tumor staging also links the modality of treatment available to a particular stage.The recent description of the tumor microenvironment(TME)in HCC has provided a new concept of immunogenicity within the HCC.Virusrelated HCC has been shown to be more immunogenic with higher expression of cytotoxic T lymphocytes and decreased elements for immunosuppression such as regulatory T cells.This immunogenic milieu provides a better response to immunotherapy especially immune checkpoint inhibitors(ICIs).In addition,the recent data on combining locoregional therapies and other strategies may convert the less immunogenic state of the TME towards higher immunogenicity.Therefore,data are emerging on the use of combinations of locoregional therapy and ICIs in unresectable or advanced HCC and has shown better survival outcomes in this difficult population.

Evaluating the influence of sarcopenia and myosteatosis on clinical outcomes in gastric cancer patients undergoing immune checkpoint inhibitor

BACKGROUND The development and progression of gastric cancer(GC)are closely linked to the nutritional status of patients.Although immunotherapy has been demonstrated to be clinically effective,the relationships of sarcopenia and myosteatosis with the use of immune checkpoint inhibitors(ICIs)in patients with gastric cancer remain to be characterized.METHODS We performed a retrospective study of patients who were undergoing immuno-therapy for GC.For the evaluation of sarcopenia,the optimal cut-off value for the skeletal muscle index was established using receiver operating characteristic analysis of data obtained from pre-treatment computed tomography images at the L3 vertebral level.Myosteatosis was defined using the mean skeletal muscle density(SMD),with a threshold value of<41 Hounsfield units(HU)for patients with a body mass index(BMI)<25 kg/m^(2)and<33 HU for those with a BMI≥25 kg/m^(2).The log-rank test was used to compare progression-free survival(PFS)and overall survival(OS),and a Cox proportional hazard model was used to identify prognostic factors.Nomograms were developed to predict the PFS and OS of patients on the basis of the results of multivariate analyses.RESULTS We studied 115 patients who were undergoing ICI therapy for GC,of whom 27.4%had sarcopenia and 29.8%had myosteatosis.Patients with sarcopenia or myosteatosis had significantly shorter PFS and OS than those without these conditions.Furthermore,both sarcopenia and myosteatosis were found to be independent predictors of PFS and OS in patients with GC administering an ICI.The prediction models created for PFS and OS were associated with C-indexes of 0.758 and 0.781,respectively.CONCLUSION The presence of sarcopenia or myosteatosis is a reliable predictor of the clinical outcomes of patients with GC who are undergoing treatment with an ICI.

Metastatic stomach lymphoepithelioma-like carcinoma and immune checkpoint inhibitor therapy:A case report

BACKGROUND Pulmonary lymphoepithelioma-like carcinoma(PLELC)is a rare type of nonsmall-cell lung cancer.Stomach lymphoepithelioma-like carcinoma(LELC)metastasis secondary to PLELC has not been reported recently.CASE SUMMARY A 64-year-old female was admitted to our hospital for a regular gastroscopy examination with a 6-year history of surgical resection for left PLELC.Positron emission tomography/computed tomography suggested high accumulation of 18F-fludeoxyglucose in the gastric cardia region.Upper gastrointestinal endoscopy confirmed a large mass at the stomach fundus.Immunohistochemistry(IHC)of the biopsy suggested metastatic stomach LELC.Proximal gastrectomy showed that this 6.5 cm×5.0 cm mass was located in the stomach fundus near the cardia.Histopathological examination showed a poorly differentiated carcinoma with prominent lymphoplasmacytic infiltration.IHC demonstrated that the tumor was positive for CK(AE1/AE3),p63,p40,p53,Ki-67(70%),and EGFR(3+)and negative for CK7,CK20,Her2,and CD10.In situ hybridization analysis showed positive staining Epstein-Barr virus-encoded RNA.Tumor programmed cell death ligand 1(PD-L1)expression score was 98%,and the combined positive score was 100,with no evidence of microsatellite instability.Thus,the patient was unequivocally diagnosed with metastatic stomach LELC secondary to pulmonary LELC.After discharge,this patient underwent PD-1 inhibitor treatment(toripalimab,240 mg)every 3 wk for ten cycles,and she has had no tumor recurrence.CONCLUSION For gastric LELC metastasis,PD-1 inhibitor therapy could become a new therapeutic approach,though there is still no evidence from large data sets to support this.

DNA damage response-related immune activation signature predicts the response to immune checkpoint inhibitors: from gastrointestinal cancer analysis to pan-cancer validation

Objective: DNA damage response(DDR) deficiency has emerged as a prominent determinant of tumor immunogenicity. This study aimed to construct a DDR-related immune activation(DRIA) signature and evaluate the predictive accuracy of the DRIA signature for response to immune checkpoint inhibitor(ICI) therapy in gastrointestinal(GI) cancer.Methods: A DRIA signature was established based on two previously reported DNA damage immune response assays. Clinical and gene expression data from two published GI cancer cohorts were used to assess and validate the association between the DRIA score and response to ICI therapy. The predictive accuracy of the DRIA score was validated based on one ICI-treated melanoma and three pan-cancer published cohorts.Results: The DRIA signature includes three genes(CXCL10, IDO1, and IFI44L). In the discovery cancer cohort, DRIA-high patients with gastric cancer achieved a higher response rate to ICI therapy than DRIA-low patients(81.8% vs. 8.8%;P < 0.001), and the predictive accuracy of the DRIA score [area under the receiver operating characteristic curve(AUC) = 0.845] was superior to the predictive accuracy of PD-L1 expression, tumor mutational burden, microsatellite instability, and Epstein–Barr virus status. The validation cohort demonstrated that the DRIA score identified responders with microsatellite-stable colorectal and pancreatic adenocarcinoma who received dual PD-1 and CTLA-4 blockade with radiation therapy. Furthermore, the predictive performance of the DRIA score was shown to be robust through an extended validation in melanoma, urothelial cancer, and pan-cancer.Conclusions: The DRIA signature has superior and robust predictive accuracy for the efficacy of ICI therapy in GI cancer and pancancer, indicating that the DRIA signature may serve as a powerful biomarker for guiding ICI therapy decisions.

Managing immune checkpoint inhibitor-associated gastritis: Insights and strategies

Immune checkpoint inhibitors(ICIs)are widely used due to their effectiveness in treating various tumors.Immune-related adverse events(irAEs)are defined as adverse effects resulting from ICI treatment.Gastrointestinal irAEs are a common type of irAEs characterized by intestinal side effects,such as diarrhea and colitis,which may lead to the discontinuation of ICIs.

Machine learning algorithms able to predict the prognosis of gastric cancer patients treated with immune checkpoint inhibitors

BACKGROUND Although immune checkpoint inhibitors(ICIs)have demonstrated significant survival benefits in some patients diagnosed with gastric cancer(GC),existing prognostic markers are not universally applicable to all patients with advanced GC.AIM To investigate biomarkers that predict prognosis in GC patients treated with ICIs and develop accurate predictive models.METHODS Data from 273 patients diagnosed with GC and distant metastasis,who un-derwent≥1 cycle(s)of ICIs therapy were included in this study.Patients were randomly divided into training and test sets at a ratio of 7:3.Training set data were used to develop the machine learning models,and the test set was used to validate their predictive ability.Shapley additive explanations were used to provide insights into the best model.RESULTS Among the 273 patients with GC treated with ICIs in this study,112 died within 1 year,and 129 progressed within the same timeframe.Five features related to overall survival and 4 related to progression-free survival were identified and used to construct eXtreme Gradient Boosting(XGBoost),logistic regression,and decision tree.After comprehensive evaluation,XGBoost demonstrated good accuracy in predicting overall survival and progression-free survival.CONCLUSION The XGBoost model aided in identifying patients with GC who were more likely to benefit from ICIs therapy.Patient nutritional status may,to some extent,reflect prognosis.

2’-Fucosyllactose alleviate immune checkpoint blockade-associated colitis by reshaping gut microbiota and activating AHR pathway

Immune checkpoint blockade(ICB)therapeutics are highly effective in cancer immunotherapy,but gastrointestinal toxicity limited the application.Intestinal microbiota plays a crucial role in ICB-associated colitis.2’-Fucosyllactose(2’FL)is most abundance prebiotic in human milk that can reshape gut microbiota and exert immune regulatory effect.The study aimed to determine the effects of 2’FL on ICB-associated colitis and to uncover the mediating mechanism.ICB-associated colitis was induced by the ipilimumab and dextran sulfate sodium.Oral administration of 2’FL(0.6 g/(kg∙day))ameliorated ICB-induced colitis by enhancing regulatory T cells(Treg)and the M2/M1 ratio of macrophages in colon.2’FL treatment also increased the expression of tight junction proteins(zonula occludens-1(ZO-1)and mucin 2(MUC2))and antioxidant stress indicators(superoxide dismutase(SOD)and catalase(CAT)).In addition,administration of 2’FL increased the abundance of Bifidobacterium and Lactobacillus,and elevated the levels of microbial metabolites,such as indole-3-lactic acid(ILA),which activated the aryl hydrocarbon receptor ligands(AHR)pathway.The protective effect of 2’FL was abolished upon depletion of gut microbiota,and ILA treatment partially simulated the protective effect of 2’FL.Notably,2’FL did not exhibit inhibition of antitumor immunity.These findings suggest that 2’FL could serve as a potential protective strategy for ICB-associated colitis by modulating the intestinal microbiota and bacterial metabolites.