GSH-responsive polymeric micelles-based augmented photoimmunotherapy synergized with PD-1 blockade for eliciting robust antitumor immunity against colon tumor.

Phototherapy is a promising antitumor modality, which consists of photothermal therapy (PTT) and photodynamic therapy (PDT). However, the efficacy of phototherapy is dramatically hampered by local hypoxia in tumors, overexpression of indoleamine 2,3-dioxygenase (IDO) and programmed cell death ligand-1 (PD-L1) on tumor cells. To address these issues, self-assembled multifunctional polymeric micelles (RIMNA) were developed to co-deliver photosensitizer indocyanine green (ICG), oxygenator MnO2, IDO inhibitor NLG919, and toll-like receptor 4 agonist monophosphoryl lipid A (MPLA). It is worth noting that RIMNA polymeric micelles had good stability, uniform morphology, superior biocompatibility, and intensified PTT/PDT effect. What's more, RIMNA-mediated IDO inhibition combined with programmed death receptor-1 (PD-1)/PD-L1 blockade considerably improved immunosuppression and promoted immune activation. RIMNA-based photoimmunotherapy synergized with PD-1 antibody could remarkably inhibit primary tumor proliferation, as well as stimulate the immunity to greatly suppress lung metastasis and distant tumor growth. This study offers an efficient method to reinforce the efficacy of phototherapy and alleviate immunosuppression, thereby bringing clinical benefits to cancer treatment.

Pharmacologic LDH inhibition redirects intratumoral glucose uptake and improves antitumor immunity in solid tumor models.

Tumor reliance on glycolysis is a hallmark of cancer. Immunotherapy is more effective in controlling glycolysis-low tumors lacking lactate dehydrogenase (LDH) due to reduced tumor lactate efflux and enhanced glucose availability within the tumor microenvironment (TME). LDH inhibitors (LDHi) reduce glucose uptake and tumor growth in preclinical models, but their impact on tumor-infiltrating T cells is not fully elucidated. Tumor cells have higher basal LDH expression and glycolysis levels compared with infiltrating T cells, creating a therapeutic opportunity for tumor-specific targeting of glycolysis. We demonstrate that LDHi treatment (a) decreases tumor cell glucose uptake, expression of the glucose transporter GLUT1, and tumor cell proliferation while (b) increasing glucose uptake, GLUT1 expression, and proliferation of tumor-infiltrating T cells. Accordingly, increasing glucose availability in the microenvironment via LDH inhibition leads to improved tumor-killing T cell function and impaired Treg immunosuppressive activity in vitro. Moreover, combining LDH inhibition with immune checkpoint blockade therapy effectively controls murine melanoma and colon cancer progression by promoting effector T cell infiltration and activation while destabilizing Tregs. Our results establish LDH inhibition as an effective strategy for rebalancing glucose availability for T cells within the TME, which can enhance T cell function and antitumor immunity.

Identification and experimental verification of a biomarker by combining the unfolded protein response with the immune cells in colon cancer.

BACKGROUND: The unfolded protein response (UPR) is associated with immune cells that regulate the biological behavior of tumors. This article aims to combine UPR-associated genes with immune cells to find a prognostic marker and to verify its connection to the UPR. METHODS: Univariate cox analysis was used to screen prognostically relevant UPRs and further screened for key UPRs among them by machine learning. ssGSEA was used to calculate immune cell abundance. Univariate cox analysis was used to screen for prognostically relevant immune cells. Multivariate cox analysis was used to calculate UPR_score and Tumor Immune Microenvironment score (TIME_score). WGCNA was used to screen UPR-Immune-related (UI-related) genes. Consensus clustering analysis was used to classify patients into molecular subtype. Based on the UI-related genes, we classified colon adenocarcinoma (COAD) samples by cluster analysis. Single-cell analysis was used to analyze the role of UI-related genes. We detected the function of TIMP1 by cell counting and transwell. Immunoblotting was used to detect whether TIMP1 was regulated by key UPR genes. RESULTS: Combined UPR-related genes and immune cells can determine the prognosis of COAD patients. Cluster analysis showed that UI-related genes were associated with clinical features of COAD. Single-cell analysis revealed that UI-related genes may act through stromal cells. We defined three key UI-related genes by machine learning algorithms. Finally, we found that TIMP1, regulated by key genes of UPR, promoted colon cancer proliferation and metastasis. CONCLUSIONS: We found that TIMP1 was a prognostic marker and experimentally confirmed that TIMP1 was regulated by key genes of UPR.

PET imaging of colon cancer CD73 expression using cysteine site-specific 89Zr-labeled anti-CD73 antibody.

CD73 is a cell-surface ectoenzyme that hydrolyzes the conversion of extracellular adenosine monophosphate to adenosine, which in turn can promote resistance to immune checkpoint blockade therapy. Immune response may therefore be improved by targeting tumor CD73, and this possibility underlines the need to non-invasively assess tumor CD73 level. In this study, we developed a cysteine site-specific 89Zr-labeled anti-CD73 (89Zr-CD73) IgG immuno-PET technique that can image tumor CD73 expression in living bodies. Anti-CD73 IgG was reduced with tris(2-carboxyethyl)phosphine, underwent sulfohydryl moiety-specific conjugation with deferoxamine-maleimide, and was radiolabeled with 89Zr. CT26 mouse colon cancer cells, CT26/CD73 cells engineered to constitutively overexpress CD73, and 4T1.2 mouse breast cancer cells underwent cell binding assays and western blotting. Balb/c nude mice bearing tumors underwent 89Zr-CD73 IgG PET imaging and biodistribution studies. 89Zr-CD73 IgG showed 20-fold higher binding to overexpressing CT26/CD73 cells compared to low-expressing CT26 cells, and moderate expressing 4T1.2 cells showed uptake that was 38.9 ± 1.51% of CT26/CD73 cells. Uptake was dramatically suppressed by excess unlabeled antibody. CD73 content proportionately increased in CT26 and CT26/CD73 cell mixtures was associated with linear increases in 89Zr-CD73 IgG uptake. 89Zr-CD73 IgG PET/CT displayed clear accumulation in CT26/CD73 tumors with greater uptake compared to CT26 tumors (3.13 ± 1.70%ID/g vs. 1.27 ± 0.31%ID/g at 8 days; P = 0.04). Specificity was further supported by low CT26/CD73 tumor-to-blood ratio of 89Zr-isotype-IgG compared to 89Zr-CD73 IgG (0.48 ± 0.08 vs. 2.68 ± 0.52 at 4 days and 0.53 ± 0.07 vs. 4.81 ± 1.02 at 8 days; both P < 0.001). Immunoblotting and immunohistochemistry confirmed strong CD73 expression in CT26/CD73 tumors and low expression in CT26 tumors. 4T1.2 tumor mice also showed clear 89Zr-CD73 IgG accumulation at 8 days (3.75 ± 0.70%ID/g) with high tumor-to-blood ratio compared to 89Zr-isotype-IgG (4.91 ± 1.74 vs. 1.20 ± 0.28; P < 0.005). 89Zr-CD73 IgG specifically targeted CD73 on high expressing cancer cells in vitro and tumors in vivo. Thus, 89Zr-CD73 IgG immuno-PET may be useful for the non-invasive monitoring of CD73 expression in tumors of living subjects.

DEPDC1B: A novel tumor suppressor gene associated with immune infiltration in colon adenocarcinoma.

BACKGROUND: Recent research indicates a positive correlation between DEP structural domain-containing 1B (DEPDC1B) and the cell cycle in various tumors. However, the role of DEPDC1B in the infiltration of the tumor immune microenvironment (TIME) remains unexplored. METHODS: We analyzed the differential expression and prognostic significance of DEPDC1B in colon adenocarcinoma (COAD) using the R package "limma" and the Gene Expression Profiling Interactive Analysis (GEPIA) website. Gene set enrichment analysis (GSEA) was employed to investigate the functions and interactions of DEPDC1B expression in COAD. Cell Counting Kit-8 (CCK-8) assays and colony formation assays were utilized to assess the proliferative function of DEPDC1B. Correlations between DEPDC1B expression and tumor-infiltrating immune cells, immune checkpoints, tumor mutational burden (TMB), and microsatellite instability (MSI) status were examined using Spearman correlation analysis and CIBERSORT. RESULTS: DEPDC1B was highly expressed in COAD. Elevated DEPDC1B expression was associated with lower epithelial-to-mesenchymal transition (EMT) and TNM stages, leading to a favorable prognosis. DEPDC1B mRNA was prominently expressed in COAD cell lines. CCK-8 and colony formation assays demonstrated that DEPDC1B inhibited the proliferation of COAD cells. Analysis using the CIBERSORT database and Spearman correlation revealed that DEPDC1B correlated with four types of tumor-infiltrating immune cells. Furthermore, high DEPDC1B expression was linked to the expression of PD-L1, CTLA4, SIGLEC15, PD-L2, TMB, and MSI-H. High DEPDC1B expression also indicated responsiveness to anti-PD-L1 immunotherapy. CONCLUSIONS: DEPDC1B inhibits the proliferation of COAD cells and positively regulates the cell cycle, showing a positive correlation with CCNB1 and PBK expression. DEPDC1B expression in COAD is associated with tumor-infiltrating immune cells, immune checkpoints, TMB, and MSI-H in the tumor immune microenvironment. This suggests that DEPDC1B may serve as a novel prognostic marker and a potential target for immunotherapy in COAD.

Prognosis poor, immune infiltration of colon adenocarcinoma associated with low expression levels of calcium-activated chloride channel.

The calcium-activated chloride channel (CLCA4) in colon adenocarcinoma (COAD) and immunological infiltration have not been extensively studied. This work thoroughly employed several datasets to assess the expression, prognosis, and association between immune infiltration and clinicopathological characteristics of CLCA4 in cancer, as well as look into potential signalling pathways. The human protein atlas (HPA), TIMER, UALCAN, TISIDB, GSCA, SangerBox, GeneMANIA, and LinkedOmics were among the datasets that were used. The findings demonstrated that, in comparison to normal tissues, COAD tissues had lower levels of CLCA4 expression. The prognosis was worse for those whose levels of CLCA4 expression were lower. For validation, immunohistochemistry (HPA) was used. Positive correlations between CLCA4 mRNA expression and its copy number variation (CNV) were observed, and CLCA4 CNV was linked to immunological infiltration. Subsequent investigation demonstrated the association between immune cell markers, immune checkpoint genes, and immunological infiltration with CLCA4. The overall survival and disease-free survival of M0 patients were considerably better than those of M1 patients, and the groups with tumour stages M0 and M1 had notably different levels of CLCA4 expression. Its substantial enrichment in ion channel activity, transmembrane transporter activity, digestion, and other biological processes was revealed by gene ontology analysis. Oxidative phosphorylation, pancreatic secretion, Parkinson's and Alzheimer's diseases, renin secretion, and other signalling pathways were the primary associations found for CLCA4. It is evident that the immunological microenvironment and functions like ion transport, metabolism, and intestinal digestion are all impacted by CLCA4 expression.

Reinvigoration of cytotoxic T lymphocytes in microsatellite instability-high colon adenocarcinoma through lysosomal degradation of PD-L1.

Compensation and intracellular storage of PD-L1 may compromise the efficacy of antibody drugs targeting the conformational blockade of PD1/PD-L1 on the cell surface. Alternative therapies aiming to reduce the overall cellular abundance of PD-L1 thus might overcome resistance to conventional immune checkpoint blockade. Here we show by bioinformatics analysis that colon adenocarcinoma (COAD) with high microsatellite instability (MSI-H) presents the most promising potential for this therapeutic intervention, and that overall PD-L1 abundance could be controlled via HSC70-mediated lysosomal degradation. Proteomic and metabolomic analyses of mice COAD with MSI-H in situ unveil a prominent acidic tumor microenvironment. To harness these properties, an artificial protein, IgP ß, is engineered using pH-responsive peptidic foldamers. This features customized peptide patterns and designed molecular function to facilitate interaction between neoplastic PD-L1 and HSC70. IgP ß effectively reduces neoplastic PD-L1 levels via HSC70-mediated lysosomal degradation, thereby persistently revitalizing the action of tumor-infiltrating CD8 + T cells. Notably, the anti-tumor effect of lysosomal-degradation-based therapy surpasses that of antibody-based immune checkpoint blockade for MSI-H COAD in multiple mouse models. The presented strategy expands the use of peptidic foldamers in discovering artificial protein drugs for targeted cancer immunotherapy.

Neutrophil-like Monocytes Increase in Patients with Colon Cancer and Induce Dysfunctional TIGIT+ NK Cells.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous family of immune cells including granulocytic (CD14neg/CD15+/HLA-DRneg) and monocytic subtypes (CD14+/CD15neg/HLA-DRneg). In the present study, we found a population of monocytes expressing the granulocyte marker CD15 that significantly increased in both peripheral blood (PB) and tumoral tissues of patients with colorectal cancer (CRC). Further phenotypical analysis confirmed the granulocytic-like features of this monocyte subpopulation that is associated with an increase in granulocyte-monocyte precursors (GMPs) in the PB of these patients (pts). Mechanistically, this granulocyte-like monocyte population suppressed NK cell activity by inducing TIGIT and engaging NKp30. Accordingly, an increased frequency of TIGIT+ NK cells with impaired functions was found in both the PB and tumoral tissue of CRC pts. Collectively, we provided new mechanistic explanations for tumor immune escape occurring in CRC by showing the increase in this new kind of MDSC, in both PB and CRC tissue, which is able to significantly impair the effector functions of NK cells, thereby representing a potential therapeutic target for cancer immunotherapy.

Local therapy with combination TLR agonists stimulates systemic anti-tumor immunity and sensitizes tumors to immune checkpoint blockade.

Toll-like receptor (TLR) agonists are being developed as anti-cancer therapeutics due to their potent immunostimulatory properties. However, clinical trials testing TLR agonists as monotherapy have often failed to demonstrate significant improvement over standard of care. We hypothesized that the anti-cancer efficacy of TLR agonist immunotherapy could be improved by combinatorial approaches. To prevent increased toxicity, often seen with systemic combination therapies, we developed a hydrogel to deliver TLR agonist combinations at low doses, locally, during cancer debulking surgery. Using tumor models of WEHI 164 and bilateral M3-9-M sarcoma and CT26 colon carcinoma, we assessed the efficacy of pairwise combinations of poly(I:C), R848, and CpG in controlling local and distant tumor growth. We show that combination of the TLR3 agonist poly(I:C) and TLR7/8 agonist R848 drives anti-tumor immunity against local and distant tumors. In addition, combination of local poly(I:C) and R848 sensitized tumors to systemic immune checkpoint blockade, improving tumor control. Mechanistically, we demonstrate that local therapy with poly(I:C) and R848 recruits inflammatory monocytes to the tumor draining lymph nodes early in the anti-tumor response. Finally, we provide proof of concept for intraoperative delivery of poly(I:C) and R848 together via a surgically applicable biodegradable hydrogel.

Unveiling an anoikis-related risk model and the role of RAD9A in colon cancer.

OBJECTIVE: Colorectal cancer (CRC), specifically colon adenocarcinoma, is the third most prevalent and the second most lethal form of cancer. Anoikis is found to be specialized form of programmed cell death (PCD), which plays a pivotal role in tumor progression. This study aimed to investigate the role of the anoikis related genes (ARGs) in colon cancer. METHODS: Consensus unsupervised clustering, differential expression analysis, tumor mutational burden analysis, and analysis of immune cell infiltration were utilized in the study. For the analysis of RNA sequences and clinical data of COAD patients, data from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) were obtained. A prognostic scoring system for overall survival (OS) prediction was developed using Cox regression and LASSO regression analysis. Furthermore, loss-of-function assay was utilized to explore the role of RAD9A played in the progression of colon cancer. RESULTS: The prognostic value of a risk score composed of NTRK2, EPHA2, RAD9A, CDC25C, and SNAI1 genes was significant. Furthermore, these findings suggested potential mechanisms that may influence prognosis, supporting the development of individualized treatment plans and management of patient outcomes. Further experiments confirmed that RAD9A could promote proliferation and metastasis of colon cancer cells. These effects may be achieved by affecting the phosphorylation of AKT. CONCLUSION: Differences in survival time and the tumor immune microenvironment (TIME) were observed between two gene clusters associated with ARGs. In addition, a prognostic risk model was established and confirmed as an independent risk factor. Furthermore, our data indicated that RAD9A promoted tumorigenicityby activating AKT in colon cancer.

Association of CD8+TILs co-expressing granzyme A and interferon-γ with colon cancer cells in the tumor microenvironment.

CD8+T cells secreting granzyme A (GZMA) can induce pyroptosis in tumor cells by effectively cleaving gasdermin B (GSDMB), which is stimulated by interferon-γ (IFN-γ). However, the interaction between GZMA-expressing CD8+T cells and GSDMB-expressing tumor cells in colon cancer remains poorly understood. Our research employed multi-color immunohistochemistry (mIHC) staining and integrated clinical data to explore the spatial distribution and clinical relevance of GZMA- and IFN-γ-expressing CD8+ tumor-infiltrating lymphocytes (TILs), as well as GSDMB-expressing CK+ cells, within the tumor microenvironment (TME) of human colon cancer samples. Additionally, we utilizing single-cell RNA sequencing (scRNA-seq) data to examine the functional dynamics and interactions among these cell populations. scRNA-seq analysis of colorectal cancer (CRC) tissues revealed that CD8+TILs co-expressed GZMA and IFN-γ, but not other cell types. Our mIHC staining results indicated that a significant reduction in the infiltration of GZMA+IFN-γ+CD8+TILs in colon cancer patients (P < 0.01). Functional analysis results indicated that GZMA+IFN-γ+CD8+TILs demonstrated enhanced activation and effector functions compared to other CD8+TIL subsets. Furthermore, GSDMB-expressing CK+ cells exhibited augmented immunogenicity. Correlation analysis highlighted a positive association between GSDMB+CK+ cells and GZMA+IFN-γ+CD8+TILs (r = 0.221, P = 0.033). Analysis of cell-cell interactions further showed that these interactions were mediated by IFN-γ and transforming growth factor-ß (TGF-ß), the co-stimulatory molecule ICOS, and immune checkpoint molecules TIGIT and TIM-3. These findings suggested that GZMA+IFN-γ+CD8+TILs modulating GSDMB-expressing tumor cells, significantly impacted the immune microenvironment and patients' prognosis in colon cancer. By elucidating these mechanisms, our present study aims to provide novel insights for the advancement of immunotherapeutic strategies in colon cancer.

MS-20 enhances the gut microbiota-associated antitumor effects of anti-PD1 antibody.

Cancer immunotherapy has been regarded as a promising strategy for cancer therapy by blocking immune checkpoints and evoking immunity to fight cancer, but its efficacy seems to be heterogeneous among patients. Manipulating the gut microbiota is a potential strategy for enhancing the efficacy of immunotherapy. Here, we report that MS-20, also known as "Symbiota®", a postbiotic that comprises abundant microbial metabolites generated from a soybean-based medium fermented with multiple strains of probiotics and yeast, inhibited colon and lung cancer growth in combination with an anti-programmed cell death 1 (PD1) antibody in xenograft mouse models. Mechanistically, MS-20 remodeled the immunological tumor microenvironment by increasing effector CD8+ T cells and downregulating PD1 expression, which were mediated by the gut microbiota. Fecal microbiota transplantation (FMT) from mice receiving MS-20 treatment to recipient mice increased CD8+ T-cell infiltration into the tumor microenvironment and significantly improved antitumor activity when combined with anti-PD1 therapy. Notably, the abundance of Ruminococcus bromii, which increased following MS-20 treatment, was positively associated with a reduced tumor burden and CD8+ T-cell infiltration in vivo. Furthermore, an ex vivo study revealed that MS-20 could alter the composition of the microbiota in cancer patients, resulting in distinct metabolic pathways associated with favorable responses to immunotherapy. Overall, MS-20 could act as a promising adjuvant agent for enhancing the efficacy of immune checkpoint-mediated antitumor therapy.

A combined radio-immunotherapy regimen eradicates late-stage tumors in mice.

Background: The majority of experimental approaches for cancer immunotherapy are tested against relatively small tumors in tumor-bearing mice, because in most cases advanced cancers are resistant to the treatments. In this study, we asked if even late-stage mouse tumors can be eradicated by a rationally designed combined radio-immunotherapy (CRI) regimen. Methods: CRI consisted of local radiotherapy, intratumoral IL-12, slow-release systemic IL-2 and anti- CTLA-4 antibody. Therapeutic effects of CRI against several weakly immunogenic and immunogenic mouse tumors including B78 melanoma, MC38 and CT26 colon carcinomas and 9464D neuroblastoma were evaluated. Immune cell depletion and flow cytometric analysis were performed to determine the mechanisms of the antitumor effects. Results: Tumors with volumes of 2,000 mm3 or larger were eradicated by CRI. Flow analyses of the tumors revealed reduction of T regulatory (Treg) cells and increase of CD8/Treg ratios following CRI. Rapid shrinkage of the treated tumors did not require T cells, whereas T cells were involved in the systemic effect against the distant tumors. Cured mice developed immunological memory. Conclusions: These findings underscore that rationally designed combination immunotherapy regimens can be effective even against large, late-stage tumors.

The intestinal flora and nutritional status and immune function characteristics of obese colon cancer patients.

BACKGROUND: The research aims to explore the characteristics of intestinal flora, nutritional status and immune function in patients with different types of obese colon cancer. METHODS: A retrospective analysis is conducted on 64 cases of obese colon cancer diagnosed from June 2018 to January 2020. According to the histological staging of the cancer, they are classified into adenocarcinoma, adenosquamous carcinoma and undifferentiated carcinoma, with corresponding cases of 24, 22 and 18, respectively. The intestinal flora (Bifidobacterium, Lactobacillus, Enterococcus faecalis, Escherichia coli, and yeast), nutritional status (Hb, Alb, PA, TFN, and PNI), immune function (IgG, IgM, IgA, CD4+, CD8+, and CD4+/CD8+) are analyzed in the different groups of patients. Survival curves are evaluated by Kaplan-Meier method and log-rank test for tumour death, local recurrence, and distant metastasis. RESULTS: There were no statistically significant differences in intestinal flora (Bifidobacterium, Lactobacillus, Enterococcus faecalis, Escherichia coli, and yeast), nutritional status (Hb, Alb, PA, TFN, and PNI) and immune function (IgG, IgM, IgA, CD4+, CD8+, and CD4+/CD8+) between different groups. There was a significant correlation between intestinal flora, nutritional status and immune function for all three. The survival curves of tumour death, local recurrence and distant metastasis in different groups of obese colon cancer patients were statistically significant. The tumor mortality rate, local recurrence, and distant metastasis rate in adenocarcinoma were 78.65%, 54.25% and 48.26% respectively. CONCLUSION: There are differences in intestinal flora, nutritional status and immune function among different types of obese colon cancer patients, but adenocarcinoma has the least benefit in intestinal flora, poor nutritional status, and weakest immune function.

Prediction and verification of targets for α-hederin/oxaliplatin dual-loaded rHDL modified liposomes: Reversing effector T-cells dysfunction and improving anti-COAD efficiency in vitro and in vivo.

This study tried to develop the α-Hederin/Oxaliplatin (OXA) dual-loaded rHDL (α-Hederin-OXA-rHDL) modified liposomes to improve the therapeutic index on colon adenocarcinoma (COAD). The α-Hederin-OXA-rHDL were prepared and evaluated for characterizations, accumulate to tumor tissues, and antitumor activity. A thorough investigation into oxaliplatin resistant and KRAS-mutant related hub keg genes were identified and performed to assess the prognosis role of the genetic signature in COAD. The potential immune signatures and molecular docking for verifing the predicted targets of α-Hederin-OXA-rHDL in tumor-bearing mice. Results suggested that α-Hederin-OXA-rHDL could enhance the sensitivity of oxaliplatin in HCT116/L-OHP cells via the regulation of KEAP1/NRF2 -mediated signaling and HO1 or GPX4 proteins. Furthermore, α-Hederin-OXA-rHDL regulated the predicted targets of PRDM1 interaction with miR-140-5p, efficient activing CD8 T cell to improve therapeutic response in vivo. Collectively, this work provides drug delivery with rHDL dual-loaded α-Hederin and oxaliplatin synergistically targets cancer cells and effectory T cells combating COAD.

γδ T cells in human colon adenocarcinomas comprise mainly Vδ1, Vδ2, and Vδ3 cells with distinct phenotype and function.

Γδ T cell infiltration into tumours usually correlates with improved patient outcome, but both tumour-promoting and tumoricidal effects of γδ T cells have been documented. Human γδ T cells can be divided into functionally distinct subsets based on T cell receptor (TCR) Vδ usage. Still, the contribution of these different subsets to tumour immunity remains elusive. Here, we provide a detailed γδ T cell profiling in colon tumours, using mass and flow cytometry, mRNA quantification, and TCR sequencing. δ chain usage in both the macroscopically unaffected colon mucosa and tumours varied considerably between patients, with substantial fractions of Vδ1, Vδ2, and non-Vδ1 Vδ2 cells. Sequencing of the Vδ complementarity-determining region 3 showed that almost all non-Vδ1 Vδ2 cells used Vδ3 and that tumour-infiltrating γδ clonotypes were unique for every patient. Non-Vδ1Vδ2 cells from colon tumours expressed several activation markers but few NK cell receptors and exhaustion markers. In addition, mRNA analyses showed that non-Vδ1 Vδ2 cells expressed several genes for proteins with tumour-promoting functions, such as neutrophil-recruiting chemokines, Galectin 3, and transforming growth factor-beta induced. In summary, our results show a large variation in γδ T cell subsets between individual tumours, and that Vδ3 cells make up a substantial proportion of γδ T cells in colon tumours. We suggest that individual γδ T cell composition in colon tumours may contribute to the balance between favourable and adverse immune responses, and thereby also patient outcome.

Intratumoral injection of mRNA encoding survivin in combination with STAT3 inhibitor stattic enhances antitumor effects.

Intratumoral delivery of mRNA encoding immunostimulatory molecules can initiate a robust, global antitumor response with little side effects by enhancing local antigen presentation in the tumor and the tumor draining lymph node. Neoantigen-based mRNA nanovaccine can inhibit melanoma growth in mice by intratumoral injection. Myeloid-derived suppressor cells (MDSCs) suppress antitumor immune responses by secreting immunosuppressive agents, such as reactive oxygen species (ROS). Suppression of STAT3 activity by stattic may reduce MDSC-mediated immunosuppression in the TME and promote the antitumor immune responses. In this study, in vitro transcribed mRNA encoding tumor antigen survivin was prepared and injected intratumorally in BALB/c mice bearing subcutaneous colon cancer tumors. In vivo studies demonstrated that intratumoral survivin mRNA therapy could induce antitumor T cell response and inhibit tumor growth of colon cancer. Depletion of CD8+ T cells could significantly inhibit survivin mRNA-induced antitumor effects. RT-qPCR and ELISA analysis indicated that survivin mRNA treatment led to increased expression of receptor activator nuclear factor-κB ligand (RANKL). In vitro experiment showed that MDSCs could be induced from mouse bone marrow cells by RANKL and RANKL-induced MDSCs could produce high level of ROS. STAT3 inhibitor stattic suppressed activation of STAT3 and NF-κB signals, thereby inhibiting expansion of RANKL-induced MDSCs. Combination therapy of survivin mRNA and stattic could significantly enhance antitumor T cell response, improve long-term survival and reduce immunosuppressive tumor microenvironment compared to each monotherapy. In addition, combined therapy resulted in a significantly reduced level of tumor cell proliferation and an obviously increased level of tumor cell apoptosis in CT26 colon cancer-bearing mice, which could be conducive to inhibit the tumor growth and lead to immune responses to released tumor-associated antigens. These studies explored intratumoral mRNA therapy and mRNA-based combined therapy to treat colon cancer and provide a new idea for cancer therapy.

Establishing a model composed of immune-related gene-modules to predict tumor immunotherapy response.

At present, tumor immunotherapy has been widely applied to treat various cancers. However, the accuracy of predicting treatment efficacy has not yet achieved a significant breakthrough. This study aimed to construct a prediction model based on the modified WGCNA algorithm to precisely judge the anti-tumor immune response. First, we used a murine colon cancer model to screen corresponding DEGs according to different groups. GSEA was used to analyze the potential mechanisms of the immune-related DEGs (irDEGs) in each group. Subsequently, the intersection of the irDEGs in every group was acquired, and 7 gene-modules were mapped. Finally, 4 gene-modules including cogenes, antiPD-1 immu-genes, chemo immu-genes and comb immu-genes, were selected for subsequent study. Furthermore, a clinical dataset of gastric cancer patients receiving immunotherapy was enrolled, and the irDEGs were identified. A total of 34 vital irDEGs were obtained from the intersections of the vital irDEGs and the four gene-modules. Next, the vital irDEGs were analyzed by the modified WGCNA algorithm, and the correlation coefficients between the 4 gene-modules and the response status to immunotherapy were calculated. Thus, a prediction model based on correlation coefficients was built, and the corresponding model scores were acquired. The AUC calculated according to the model score was 0.727, which was non-inferior to that of the ESTIMATE score and the TIDE score. Meanwhile, the AUC calculated according to the classification of the model scores was 0.705, which was non-inferior to that of the ESTIMATE classification and the TIDE classification. The prediction accuracy of the model was validated in clinical datasets of other cancers.

Machine learning evaluation of immune infiltrate through digital tumour score allows prediction of survival outcome in a pooled analysis of three international stage III colon cancer cohorts.

BACKGROUND: T-cell immune infiltrates are robust prognostic variables in localised colon cancer. Evaluation of prognosis using artificial intelligence is an emerging field. We evaluated whether machine learning analysis improved prediction of patient outcome in comparison with analysis of T cell infiltrate only or in association with clinical variables. METHODS: We used data from two phase III clinical trials (Prodige-13 and PETACC08) and one retrospective Italian cohort (HARMONY). Cohorts were split into training (N = 692), internal validation (N = 297) and external validation (N = 672) sets. Tumour slides were stained with CD3mAb. CD3 Machine Learning (CD3ML) score was computed using graphical parameters within the tumour tiles obtained from CD3 slides. CD3 infiltrates in tumour core and invasive margin were automatically detected. Associations of CD3 infiltrates and CD3ML with 5-year Disease-Free Survival (DFS) were examined using univariate and multivariable survival models by Cox regression. FINDINGS: CD3 density both in the invasive margin and the tumour core were significantly associated with DFS in the different sets. Similarly, CD3ML score was significantly associated with DFS in all sets. CD3 assessment did not provide added value on top of CD3ML assessment (Likelihood Ratio Test (LRT), p = 0.13). In contrast, CD3ML improved prediction of DFS when combined with a clinical risk stage (LRT, p = 0.001). Stratified by clinical risk score (High or Low), patients with low CD3ML score had better DFS. INTERPRETATION: In all tested sets, machine learning analysis of tumour cells improved prediction of prognosis compared to clinical parameters. Adding tumour-infiltrating lymphocytes assessment did not improve prognostic determination. FUNDING: This research received no external funding.

MC1R regulates T regulatory cell differentiation through metabolic reprogramming to promote colon cancer.

BACKGROUND: Until 2021, colon cancer was a leading cancer globally. Early detection improves outcomes; however, advanced cases still having poor prognosis. Therefore, an understanding of associated molecular mechanisms is crucial for developing new preventive and therapeutic strategies for colon cancer. METHODS: The TCGA database was analyzed to assess melanocortin 1receptor (MC1R) expression in colon cancer and its link with patient prognosis. Further, models and diverse experimental techniques were employed to investigate the impact of MC1R on colon cancer progression and its underlying mechanism was elucidated. RESULTS: In a follow-up study of clinical patients, the important role of MC1R was identified in the development of colon cancer. First, MC1R was expressed more highly in colon tumor tissues than in adjacent tissues. In addition, MC1R was associated with colon cancer prognosis, and higher expression of MC1R tended to predict a worse prognosis. This conclusion was verified in MC1R-/- mice, which showed a greater resistance to tumor growth than wild-type mice, as expected. Further investigation revealed a significant change in the portion of Tregs in MC1R-/- mice, while the portion of CD4 + and CD8 + T cells remained unchanged. The in vitro experiments revealed a weaker ability of the MC1R-/- T cells to differentiate into Tregs. Previous studies report that the functional integrity of Tregs is interwoven with cellular metabolism. Therefore, MC1R was deduced to regulate the differentiation of Tregs by reprogramming the metabolism. As expected, MC1R-/- T cells exhibited weaker mitochondrial function and a lower aerobic oxidation capacity. Concurrently, the MC1R-/- T cells had stronger limiting effects on colon cancer cells. According to these results, the MC1R inhibitor was hypothesized as a potential therapeutic agent to suppress colon cancer. The results showed that upon MC1R suppression, the tumors in the mice developed more slowly, and the mice survived longer, potentially providing a novel strategy to treat clinical colon cancer. CONCLUSION: By regulating Tregs differentiation, MC1R overexpression in colon cancer correlates with poor prognosis, while MC1R inhibition shows potential as a therapeutic approach to slow tumor growth and enhance survival.