Involvement of tumor immune microenvironment metabolic reprogramming in colorectal cancer progression, immune escape, and response to immunotherapy

Recent advances in biomimetic nanodelivery systems for cancer Immunotherapy

Tumor immunotherapy is a developing and promising therapeutic method. However, the mechanism of tumor immune microenvironment and individual differences of patients make the clinical application of immunotherapy still very limited. The resulting targeting of the tumor environment and immune system is a suitable strategy for tumor therapy. Biomimetic nanodelivery systems (BNDS) coated with nanoparticles has brought new hope for tumor immunotherapy. Due to its high targeting, maximum drug delivery efficiency and immune escape, BNDS has become one of the options for tumor immunotherapy in the future. BNDS combines the advantages of natural cell membranes and nanoparticles and has good targeting properties. This review summarizes the relationship between tumor and immune microenvironment, classification of immunotherapy, engineering modification of cell membrane, and a comprehensive overview of different types of membrane BNDS in immunotherapy. Furthermore, the prospects and challenges of biomimetic nanoparticles coated with membranes in tumor immunotherapy are further discussed.

Overcoming the novel glycan-lectin checkpoints in tumor microenvironments for the success of the cross-presentation-based immunotherapy

In pursuit of meeting the ever-rising demand for cancer therapies, cross-presentation-based glyconanovaccines (GNVs) targeting C-type lectin receptors (CLRs) on DCs have shown significant potential as cutting-edge cancer immunotherapy. GNVs are an attractive approach to induce anti-cancer cytotoxic T lymphocyte responses. Despite immune checkpoints (ICs) being well established and an obstacle to the success of GNVs, glycan-lectin circuits are emerging as unique checkpoints due to their immunomodulatory functions. Given the role of aberrant tumor glycosylation in promoting immune evasion, mitigating these effects is crucial for the efficacy of GNVs. Lectins, such as siglecs and galectins, are detrimental to the tumor immune landscape as they promote an immunosuppressive TME. From this perspective, this review aims to explore glycan-lectin ICs and their influence on the efficacy of GNVs. We aim to discuss various ICs in the TME followed by drawbacks of immune checkpoint inhibitors (ICIs). We will also emphasize the altered glycosylation profile of tumors, addressing their immunosuppressive nature along with ways in which CLRs, siglecs, and galectins contribute to immune evasion and cancer progression. Considering the resistance towards ICIs, current and prospective approaches for targeting glycan-lectin circuits and future prospects of these endeavors in harnessing the full potential of GNVs will also be highlighted.

KRAS mutations in colorectal cancer: impacts on tumor microenvironment and therapeutic implications

INTRODUCTION

Despite decreasing trends in incidence, colorectal cancer (CRC) is still a major contributor to malignancy-related morbidities and mortalities. Groundbreaking advances in immunotherapies and targeted therapies benefit a subset of CRC patients, with sub-optimal outcomes. Hence, there is an unmet need to design and manufacture novel therapies, especially for advanced/metastatic disease. KRAS, the most highly mutated proto-oncogene across human malignancies, particularly in pancreatic adenocarcinoma, non-small cell lung cancer, and CRC, is an on-off switch and governs several fundamental cell signaling cascades. KRAS mutations not only propel the progression and metastasis of CRC but also critically modulate responses to targeted therapies.

AREAS COVERED

We discuss the impacts of KRAS mutations on the CRC's tumor microenvironment and describe novel strategies for targeting KRAS and its associated signaling cascades and mechanisms of drug resistance.

EXPERT OPINION

Drug development against KRAS mutations has been challenging, mainly due to structural properties (offering no appropriate binding site for small molecules), critical functions of the wild-type KRAS in non-cancerous cells, and the complex network of its downstream effector pathways (allowing malignant cells to develop resistance). Pre-clinical and early clinical data offer promises for combining KRAS inhibitors with immunotherapies and targeted therapies.

DBI as a Novel Immunotherapeutic Candidate in Colorectal Cancer: Dissecting Genetic Risk and the Immune Landscape via GWAS, eQTL, and pQTL

Background: Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide. Identifying drug targets associated with CRC is crucial for developing targeted therapies. Methods: MR (IVW, Wald ratio, weighted median, and MR-Egger) and SMR analyses were used to screen candidate genes associated with CRC risk. Further validation was performed using The Cancer Genome Atlas (TCGA) to assess gene expression patterns and prognostic significance. Additionally, immune infiltration analysis was conducted to characterize the tumor immune microenvironment. Drug prediction was performed to explore potential therapeutic interventions. Results: Eight genes were identified associated with CRC. IGFBP3, CD72, SERPINH1, CHRDL2, LRP11, and SPARCL1 were linked to an increased risk of CRC, whereas DBI and HYAL1 were associated with a decreased risk of CRC. Notably, DBI exhibited a potentially favorable immune profile, negatively correlated with Tregs and MDSCs while positively associated with activated CD8+ and CD4+ T cells. Conclusions: Eight genes were identified as associated with CRC, among which DBI exhibited a potential protective role, correlating with improved patient survival, enhanced immune activation, and increased responsiveness to immunotherapy. The remaining proteins demonstrated diverse and complex functions within the tumor immune microenvironment, providing novel insights for the development of precision diagnostics and immunotherapeutic strategies.

The Novel Dual GIP and GLP-1 Receptor Agonist Tirzepatide Attenuates Colon Cancer Development by Regulating Glucose Metabolism

Colorectal cancer (CRC) is a leading cause of cancer mortality while diabetes is a recognized risk factor for CRC. Here we report that tirzepatide (TZP), a novel polypeptide/glucagon-like peptide 1 receptor (GIPR/GLP-1R) agonist for the treatment of diabetes, has a role in attenuating CRC growth. TZP significantly inhibited colon cancer cell proliferation promoted apoptosis in vitro and induced durable tumor regression in vivo under hyperglycemic and nonhyperglycemic conditions across multiple murine cancer models. As glucose metabolism is known to critically regulate colon cancer progression, spatial metabolomics results revealed that glucose metabolites are robustly reduced in the colon cancer regions of the TZP-treated mice. TZP inhibited glucose uptake and destabilized hypoxia-inducible factor-1 alpha (HIF-1α) with reduced expression and activity of the rate-limiting enzymes 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) and phosphofructokinase 1 (PFK-1). These effects contributed to the downregulation of glycolysis and the tricarboxylic acid (TCA) cycle. TZP also delayed tumor development in a patient-derived xenograft (PDX) mouse model accompanied by HIF-1α mediated PFKFB3-PFK-1 inhibition. Therefore, the study provides strong evidence that glycolysis-blocking TZP, besides its application in treating type 2 diabetes, has the potential for preclinical studies as a therapy for colorectal cancer used either as monotherapy or in combination with other anticancer therapies.

RBM15-mediated metabolic reprogramming boosts immune response in colorectal cancer

Introduction

Immune checkpoint blockade (ICB) therapy has shown promise in treating advanced colorectal cancer, particularly in patients with microsatellite instability-high (MSI-H) tumors. However, only a subset of these patients responds favorably, highlighting the need for strategies to improve immunotherapy efficacy.

Methods

To identify potential regulators of immunotherapy response, we conducted a comprehensive analysis of colorectal cancer datasets from The Cancer Genome Atlas (TCGA). We performed multi-omics analyses and functional assays in both human and murine colorectal cancer cell lines. Additionally, we evaluated tumor growth and immune cell infiltration using syngeneic mouse models.

Results

Our analysis revealed that RNA binding motif protein 15 (RBM15) is highly expressed in colorectal cancer and correlates with poor patient prognosis. Functional studies demonstrated that RBM15 loss led to increased expression of fumarate hydratase (FH). This led to decreased levels of fumarate, a metabolite known to suppress anti-tumor immune responses. In vivo, RBM15 depletion significantly delayed tumor progression and enhanced CD8⁺ T cell infiltration and activation in the tumor microenvironment.

Discussion

These findings identify RBM15 as a negative regulator of anti-tumor immunity in colorectal cancer. Targeting RBM15 may represent a novel strategy to boost immune responsiveness and improve outcomes for patients undergoing immunotherapy.

Comprehensive insights into carbonic anhydrase inhibition: A triad of In vitro, In silico, and In vivo perspectives

Carbonic anhydrases (CAs) are zinc-dependent metalloenzymes essential for sustaining physiological balance by facilitating the reversible conversion of carbon dioxide to its hydrated form. Their biological significance, coupled with their involvement in a wide array of pathological conditions, makes them attractive targets for therapeutic intervention. This review presents a comprehensive analysis of carbonic anhydrase inhibition through an integrated triad of in vitro, In silico, and In vivo perspectives. In vitro studies provide critical insights into the mechanisms of enzyme inhibition, enabling the identification and optimization of potent inhibitors while elucidating their structure-activity relationships. In silico methodologies, including docking, molecular dynamics (MD) simulation, virtual screening, ADMET, and QSAR analyses, have emerged as invaluable tools in rational drug design, streamlining the discovery and development of isoform-specific inhibitors. Complementing these efforts, In vivo investigations validate the pharmacokinetics, pharmacodynamics, and therapeutic efficacy of CA inhibitors (CAIs) in disease models, bridging the gap between laboratory findings and clinical applications. The therapeutic relevance of CAIs extends across multiple domains, including glaucoma, epilepsy, cancer, metabolic disorders, and infectious diseases. Emerging applications, such as their potential use in combating antimicrobial resistance and modulating immune responses, further underscore their versatility. However, challenges such as achieving isoform selectivity, minimizing off-target effects, and translating preclinical findings into clinical success persist. Advances in fragment-based drug design, artificial intelligence-driven discovery, and innovative experimental techniques are poised to address these limitations, paving the way for the next generation of CAIs.

Comprehensive pan-cancer single-cell analysis reveals glycolysis-related signatures as predictive biomarkers for immunotherapy response and their role in bladder cancer

Glycolysis is a vital metabolic biological process in tumor progression and immune modulation. This study comprehensively investigated the roles of glycolysis in pan-cancer, especially in bladder cancer. Exploration of 34 single-cell RNA sequencing (scRNA-seq) cohorts, eight ICI-treated bulk RNA-seq cohorts, and TCGA bulk pan-cancer RNA-seq cohorts uncovered a Glycolysis.Sig which strongly correlated with immunotherapy response and demonstrated excellent predictive performance in prognosis and immune response. Hub-Glycolysis.Sig exhibited varying interactions with the immune microenvironment based on cancer type. In bladder cancer, higher glycolysis risk scores correlated with poorer prognosis, with distinct immune infiltration characteristics between subtypes. scRNA-seq revealed high glycolysis levels in bladder epithelial cells. COPB2 was highly expressed in bladder cancer, promoting cell proliferation, migration, and glycolytic activity in vitro and in vivo. Our large-scale data analysis confirmed the negative correlation between glycolysis and immunotherapy outcomes, identifying Glycolysis.Sig as a novel predictive biomarker. Hub-Glycolysis.Sig provides clinical insights for bladder cancer therapy strategies, while COPB2 and other potential therapeutic targets facilitate personalized cancer treatment.

Tumor Microenvironment Lactate: Is It a Cancer Progression Marker, Immunosuppressant, and Therapeutic Target?

The "Warburg effect" is a term coined a century ago for the preferential use of glycolysis over aerobic respiration in tumor cells for energy production, even under aerobic conditions. Although this is a less efficient mechanism of generating energy from glucose, aerobic glycolysis, in addition to the canonical anaerobic glycolysis, is an effective means of lactate production. The abundant waste product, lactate, yielded by the dual glycolysis in a tumor, has been discovered to be a major biomolecule that drives cancer progression. Lactate is a metabolic energy source that, via cell membrane lactate transporters, shuttles in and out of cancer cells as well as cancer cell-associated stromal cells and immune cells within the tumor microenvironment (TME). Additionally, lactate serves as a pH tuner, signaling ligand and transducer, epigenetic and gene transcription regulator, TME modifier, immune suppressor, chemoresistance modulator, and prognostic marker. With such broad functionalities, the production-consumption-reproduction of TME lactate fuels tumor growth and dissemination. Here, we elaborate on the lactate sources that contribute to the pool of lactate in the TME, the functions of TME lactate, the influence of the TME lactate on immune cell function and local tissue immunity, and anticancer therapeutic approaches adopting lactate manipulations and their efficacies. By scrutinizing these properties of the TME lactate and others that have been well addressed in the field, it is expected that a better weighing of the influence of the TME lactate on cancer development, progression, prognosis, and therapeutic efficacy can be achieved.

Prospects of engineered bacteria-assisted CAR T Cell therapy in gastrointestinal cancers

The high incidence and mortality rates associated with gastrointestinal cancers represent a significant global health challenge. In recent years, CAR T cell therapy has emerged as a promising immunotherapeutic approach, demonstrating favorable clinical outcomes. However, the application of traditional CAR T cell therapy in gastrointestinal cancers faces numerous challenges, including the suppressive tumor microenvironment and limitations in anti-tumor efficacy. The application of engineered bacteria offers a novel strategy to enhance CAR T cell therapy by modulating the tumor microenvironment and boosting immune responses, potentially leading to improved therapeutic outcomes. This review synthesizes the current research advancements related to engineered bacteria-assisted CAR T cell therapy in gastrointestinal cancers, exploring its underlying mechanisms, clinical applications, and future developmental directions.

Exploring the Role of Cellular Interactions in the Colorectal Cancer Microenvironment

Colorectal cancer (CRC) stands as one of the tumors with globally high incidence and mortality rates. In recent years, researchers have extensively explored the role of the tumor immune microenvironment (TME) in CRC, highlighting the crucial influence of immune cell populations in driving tumor progression and shaping therapeutic outcomes. The TME encompasses an array of cellular and noncellular constituents, spanning tumor cells, immune cells, myeloid cells, and tumor-associated fibroblasts, among others. However, the cellular composition within the TME is highly dynamic, evolving throughout different stages of tumor progression. These shifts in cell subpopulation proportions lead to a gradual transition in the immune response, shifting from an early antitumor growth to a late-stage environment that supports tumor survival. Therefore, it is crucial to further investigate and understand the complex interactions among the various cell populations within the TME. In this review, we explore the key cellular components of varying origins, subpopulations with shared origins, and noncellular elements within the CRC TME, examining their interconnections and critical considerations for developing personalized and precise immunotherapy strategies.

Bufalin inhibits immune escape in metastatic colorectal cancer by regulating M2 macrophage polarization

The prognosis for patients with metastatic colorectal cancer (mCRC) remains poor primarily owing to immune escape caused by immunosuppressive tumor microenvironment (TME). M2 tumor-associated macrophages (TAMs) have been considered as a pivotal role in sustaining the immunosuppressive character in TME. Our previous studies have found that highly mCRC cells could promote M2 TAMs polarization, leading to the exhaustion of T cell antitumor immunity. Studies have reported that Bufalin (BU) could reverse the immunosuppressive TME via regulating TAMs polarization, but the mechanisms underlying remain elusive. In this study, we demonstrated that KLF4 secreted by highly mCRC cells not only promoted the polarization to M2 TAMs but also up-regulated the PD-L1 expression in TAMs, leading to suppressing cytotoxic T lymphocyte (CTL) function to facilitate tumor immune escape. Mechanistically, BU targeted the SRC-3 protein to reduce KLF4 release in highly mCRC cells to regulate the polarization of M2 TAMs and down-regulate PD-L1 expression in TAMs, resulting in reprogramming of the TME and enhancing the anti-tumor immunity. These results have also been validated in both subcutaneous tumor models and orthotopic tumor models. Overall, this research further elucidates the anti-tumor mechanism of BU for inhibiting immune escape in mCRC and facilitate exploitation of a new potential macrophage-based mCRC immunotherapeutic modality.

Effect of compound kushen injection on immune function in patients with colorectal cancer: a systematic review and meta-analysis

Background

Colorectal cancer (CRC) is one of the most common malignant tumors worldwide. Chemotherapy and radiotherapy remain cornerstone treatments; however, they often lead to significant immune suppression and an increased risk of infection. Enhancing immune function in CRC patients is critical for improving clinical outcomes and prognosis.

Objective

To evaluate the effects of Compound Kushen Injection (CKI) on immune function and its role in mitigating chemotherapy-induced adverse effects in patients with CRC.

Methods

We retrieved randomized controlled trials (RCTs) evaluating the effects of CKI on immune function in patients with CRC from eight Chinese and English databases, up until 31 December 2024. The Cochrane Handbook was used to assess the quality of the included studies. For the meta-analysis, we utilized Review Manager 5.4.1 software. Sensitivity analysis and publication bias assessment were conducted using Stata 17.0 software.

Result

A total of 2,663 patients (1,550 males and 1,113 females) from 30 RCTs were included. Compared to conventional chemotherapy (CC), the combination of CKI with CC significantly enhanced immune function, increasing CD3+ levels (MD = 6.15, 95% CI: 4.78 to 7.53, p < 0.00001), CD4+ levels (MD = 8.05, 95% CI: 6.99 to 9.11, p < 0.00001), CD4+/CD8+ levels (MD = 0.36, 95% CI: 0.28 to 0.44, p < 0.00001), NK cell levels (MD = 3.60, 95% CI: 2.85 to 4.34, p < 0.00001), while reducing CD8+ levels (MD = -4.19, 95% CI: -5.11 to -3.27, p < 0.00001). CKI also improved the objective response rate (ORR, RR = 1.50, 95% CI: 1.38 to 1.62, p < 0.00001) and disease control rate (DCR, RR = 1.15, 95% CI: 1.10 to 1.19, p < 0.00001), decreased CEA levels (MD = -1.79, 95% CI: -2.81 to -0.76, p = 0.0007) and CA199 levels (MD = -0.73, 95% CI: -1.35 to -0.12, p = 0.02), and reduced chemotherapy-induced adverse reactions, including nausea, vomiting, hepatic dysfunction, myelosuppression, neurotoxicity, leukopenia, thrombocytopenia, and mouth ulcers.

Conclusion

Current evidence suggests that the combination of CKI with CC may have beneficial effects on immune function, ORR, DCR, and chemotherapy-induced adverse reactions in CRC patients. However, given the variability in study quality and the absence of disease stage stratification, these findings should be interpreted with caution. Furthermore, the lack of long-term follow-up data limits the understanding of CKI's impact on survival and quality of life. High-quality, large-scale RCTs with extended follow-up are needed to further assess the long-term efficacy, safety, and clinical applicability of CKI in CRC management.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=632516, identifier CRD42025632516.

Potential of Glycyrrhiza in the prevention of colitis-associated colon cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Glycyrrhiza, a legume native to the Mediterranean region, has a long history of ethnomedicinal use in China. Due to its antiviral, antibacterial, anti-inflammatory, antioxidant, antitumor, anti-ulcer, and hepatoprotective properties, Glycyrrhiza is widely utilized in the treatment of gastrointestinal disorders.

THE AIM OF THE REVIEW

The specific mechanisms of the main active constituents of glycyrrhiza in the treatment of inflammatory bowel disease, precancerous lesions and colorectal cancer at all stages of the colitis-associated colon cancer "Inflammation-Dysplasia-Cancer" sequence, as well as its pharmacokinetics, toxicology, formulation improvements, and application studies, are reviewed to provide new insights and perspectives on glycyrrhiza as a dietary supplement to treat and prevent colitis-associated colon cancer.

MATERIALS AND METHODS

Information on Glycyrrhiza was retrieved from electronic databases, including PubMed and Web of Science.

RESULTS

Glycyrrhiza is a well-established medicinal plant with significant potential for applications in both the food and pharmaceutical industries. Over 400 active constituents have been identified in Glycyrrhiza, including terpenoids, flavonoids, isoflavones, coumarins, and polyphenols. Numerous studies have demonstrated that Glycyrrhiza and its active compounds can inhibit the "Inflammation-Dysplasia-Cancer" progression of colitis-associated colon cancer by mitigating inflammatory bowel disease, reducing the number of intestinal precancerous lesions, and counteracting colorectal cancer. Furthermore, derivatives and nanocarriers are crucial for the effective treatment of colitis-associated colon cancer using Glycyrrhiza and its active constituents.

CONCLUSION

In conclusion, Glycyrrhiza is a plant with both medicinal and nutritional value, making it a potential food ingredient and dietary supplement for the treatment of colitis-associated colon cancer.

Untangling the Role of MYC in Sarcomas and Its Potential as a Promising Therapeutic Target

MYC plays a pivotal role in the biology of various sarcoma subtypes, acting as a key regulator of tumor growth, proliferation, and metabolic reprogramming. This oncogene is frequently dysregulated across different sarcomas, where its expression is closely intertwined with the molecular features unique to each subtype. MYC interacts with critical pathways such as cell cycle regulation, apoptosis, and angiogenesis, amplifying tumor aggressiveness and resistance to standard therapies. Furthermore, MYC influences the tumor microenvironment by modulating cell-extracellular matrix interactions and immune evasion mechanisms, further complicating therapeutic management. Despite its well-established centrality in sarcoma pathogenesis, targeting MYC directly remains challenging due to its "undruggable" protein structure. However, emerging therapeutic strategies, including indirect MYC inhibition via epigenetic modulators, transcriptional machinery disruptors, and metabolic pathway inhibitors, offer new hope for sarcoma treatment. This review underscores the importance of understanding the intricate roles of MYC across sarcoma subtypes to guide the development of effective targeted therapies. Given MYC's central role in tumorigenesis and progression, innovative approaches aiming at MYC inhibition could transform the therapeutic landscape for sarcoma patients, providing a much-needed avenue to overcome therapeutic resistance and improve clinical outcomes.

Targeting the AURKB-MAD2L2 Axis Disrupts the DNA Damage Response and Glycolysis to Inhibit Colorectal Cancer Progression

BACKGROUND

Dysregulated metabolic pathways, including glycolysis and a compromised DNA damage response (DDR), are linked to the progression of colorectal cancer (CRC). The mitotic arrest deficient-like 2 (MAD2L2) and aurora kinase B (AURKB) genes play roles in cell cycle regulation and the DDR, making them potential targets for CRC therapy.

METHODS

Differential expression analysis was performed using The Cancer Genome Atlas-Colon Adenocarcinoma (TCGA-COAD) and GSE47074 datasets. A predictive model was established, and gene expression levels were further analyzed. The Gene Expression Profiling Interaction Analysis database and co-immunoprecipitation experiments assessed the correlation between AURKB and MAD2L2. Knockdown experiments in CRC cell lines further investigated the role of AURKB, followed by analyses of cell behavior, oxidative stress, glycolysis, DDR, and interaction with MAD2L2.

RESULTS

The risk model identified six prognostic genes (BUB1 mitotic checkpoint serine/threonine kinase B (BUB1B), AURKB, aurora kinase A (AURKA), exonuclease 1 (EXO1), topoisomerase II alpha (TOP2A), cyclin A2 (CCNA2)) associated with CRC, which were significantly expressed in tumor samples from the TCGA-COAD and GSE47074 datasets. In vitro assays confirmed that AURKB knockdown inhibited CRC cell behavior, induced G1 cell cycle arrest, and increased oxidative stress and apoptosis. AURKB knockdown also impaired glycolysis, reducing lactate production, glucose uptake, and ATP levels. Overexpression of MAD2L2 partially reversed these effects, restored glycolytic activity, and mitigated the cell cycle arrest and DDR caused by AURKB knockdown.

CONCLUSION

AURKB regulates CRC progression by modulating glycolysis and DDR pathways. Targeting the AURKB-MAD2L2 axis offers a promising therapeutic strategy for disrupting fundamental metabolic and DNA repair mechanisms in CRC.

Exploring the Link Between Noncoding RNAs and Glycolysis in Colorectal Cancer

Glycolysis is implicated in the onset and progression of colorectal cancer (CRC) through its influence on the proliferation, invasiveness, chemoresistance and immune system evasion of neoplasm cells. Increasing evidence has shown that the abnormal expression of noncoding RNAs (ncRNAs), especially microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), in CRC is closely related to glycolysis. In this review, we present a synthesis of the latest research insights into the modulatory roles and distinct pathways of ncRNAs in the glycolytic process in CRC. This knowledge may pave the way for identifying novel therapeutic targets, as well as novel prognostic and diagnostic biomarkers for CRC.

Role of amino acid metabolism in tumor immune microenvironment of colorectal cancer

This review investigates the role of amino acid metabolism in the tumor microenvironment of colorectal cancer (CRC) and explores potential targeted therapeutic strategies. The paper synthesized current research on amino acid metabolism in the colorectal cancer tumor microenvironment, focusing on amino acids such as tryptophan, methionine, glutamine, and arginine. It examined their impact on tumor growth, immune evasion, and patient prognosis, as well as the metabolic reprogramming of tumor cells and complex tumor microenvironment interactions. Aberrant amino acid metabolism was a hallmark of colorectal cancer, influencing tumor proliferation, survival, and invasiveness. Key findings included: Tryptophan metabolism via the kynurenine and serotonin pathways significantly affected immune response and tumor progression in CRC. Methionine influenced T cell function and DNA methylation, playing a critical role in tumor development. Glutamine was extensively used by tumor cells for energy metabolism and supported immune cell function. Arginine metabolism impacted CD8+ T cell functionality and tumor growth. The review also discussed the dual roles of immune cells in the tumor microenvironment and the potential of targeting amino acid metabolic pathways for CRC treatment. In conclusion, amino acid metabolism significantly impacts the colorectal cancer tumor microenvironment and immunity. Understanding these metabolic pathways provides valuable insights into CRC pathogenesis and identifies potential therapeutic targets. Future research should focus on developing treatments that disrupt these metabolic processes to improve patient outcomes in CRC.

A novel nanomedicine integrating ferroptosis and photothermal therapy, well-suitable for PD-L1-mediated immune checkpoint blockade

Immunotherapy based on immune checkpoint blockade has emerged as a promising treatment strategy; however, the therapeutic efficacy is limited by the immunosuppressive microenvironment. Here, we developed a novel immune-activated nanoparticle (Fc-SS-Fe/Cu) to address the issue of insufficient immune infiltration. Specifically, the structure of Fc-SS-Fe/Cu collapsed in response to the tumor microenvironment, the ferrocene and disulfide bonds and the released Fe/Cu ions can effectively generate ·OH and deplete GSH to increase oxidative stress, thereby inducing ferroptosis. Withal, the positive feedback mechanisms of "laser-triggered mild-temperature photothermal therapy (PTT), PTT accelerated ferroptosis and LPO accumulation, LPO mediated HSPs down-regulated to promote PTT," effectively triggers immunogenic cell death (ICD) in tumor cells, significantly enhancing their immunogenicity. Moreover, the O2-generating ability induced by Fc-SS-Fe/Cu could reverse the hypoxic tumor microenvironment, and importantly, the expression of PD-L1 on tumor cell surfaces could be effectively downregulated by inhibiting the HIF-1α pathways, thereby augmenting the effect of anti-PD-L1 (αPD-L1) therapy. Therefore, this study provides valuable strategies into enhancing PD-L1-mediated ICB therapy.

The Major Role of T Regulatory Cells in the Efficiency of Vaccination in General and Immunocompromised Populations: A Review

Since their conception with the smallpox vaccine, vaccines used worldwide have mitigated multiple pandemics, including the recent COVID-19 outbreak. Insightful studies have uncovered the complexities of different functional networks of CD4 T cells (T helper 1 (Th1); Th2, Th17) and CD8 T cells (T cytotoxic; Tc), as well as B cell (BIgM, BIgG, BIgA and BIgE) subsets, during the response to vaccination. Both T and B cell subsets form central, peripheral, and tissue-resident subsets during vaccination. It has also become apparent that each vaccination forms a network of T regulatory subsets, namely CD4+ CD25+ Foxp3+ T regulatory (Treg) cells and interleukin-10 (IL-10)-producing CD4+ Foxp3- T regulatory 1 (Tr1), as well as many others, which shape the quality/quantity of vaccine-specific IgM, IgG, and IgA antibody production. These components are especially critical for immunocompromised patients, such as older individuals and allograft recipients, as their vaccination may be ineffective or less effective. This review focuses on considering how the pre- and post-vaccination Treg/Tr1 levels influence the vaccination efficacy. Experimental and clinical work has revealed that Treg/Tr1 involvement evokes different immune mechanisms in diminishing vaccine-induced cellular/humoral responses. Alternative steps may be considered to improve the vaccination response, such as increasing the dose, changing the delivery route, and/or repeated booster doses of vaccines. Vaccination may be combined with anti-CD25 (IL-2Rα chain) or anti-programmed cell death protein 1 (PD-1) monoclonal antibodies (mAb) to decrease the Tregs and boost the T/B cell immune response. All of these data and strategies for immunizations are presented and discussed, aiming to improve the efficacy of vaccination in humans and especially in immunocompromised and older individuals, as well as organ transplant patients.