Colon-specific immune microenvironment regulates cancer progression versus rejection

RBM15 increase tumor-infiltrating CD4+ T cell in ESCC via modulating of PLOD3

BACKGROUND

Collagen, a primary protein component of the extracellular matrix (ECM), undergoes a notable series of alterations concomitant with the growth of the tumor. Procollagen-lysine,2-oxoglutarate 5-dioxygenase 3 (PLOD3) is involved in the synthesis of collagen and has been associated with a variety of cancers. However, it is unclear how PLOD3 functions in esophageal squamous cell carcinoma (ESCC).

METHODS

Differentially expressed genes between ESCC and adjacent normal tissues were identified using proteomic and transcriptomic analyses. These genes were then subjected to survival analysis to identify prognostic markers. Immune cell infiltration in the two subgroups was evaluated. Spearman's correlation analysis was performed to examine the correlation between PLOD3 and RBM15 expression in TCGA-ESCC database. shRNA-mediated approach was used to knockdown RBM15 in ESCC cells. The effects of RBM15 knockdown on PLOD3 expression were assessed by real-time PCR and Western blot. Moreover, COX algorithm was employed to construct a prognostic signature.

RESULTS

PLOD3 was found to be highly expressed in ESCC patients and correlated with a favorable prognosis. Immune cell infiltration estimation indicated tumor-infiltrating CD4+ T cell was increased in PLOD3-high group. Correlation analysis revealed that PLOD3 was associated with RBM15 and was closely related to CD4+ T cell infiltration. Moreover, loss-of-function approaches showed that depletion of RBM15 attenuated PLOD3 expression in ESCC cells. Following univariate and multivariate Cox regression analyses, PLOD3 and RBM15 were identified as a two-gene prognostic signature for ESCC.

CONCLUSION

RBM15 enhances tumor-infiltrating CD4+ T Cell abundance in ESCC by regulating PLOD3. Two new independent prognostic factors, PLOD3 and RBM15, may be useful in predicting the prognosis of ESCC.

Colorectal cancer: Recent advances in management and treatment

Colorectal cancer (CRC) is the third most common cancer worldwide, and the second most common cause of cancer-related death. In 2020, the estimated number of deaths due to CRC was approximately 930000, accounting for 10% of all cancer deaths worldwide. Accordingly, there is a vast amount of ongoing research aiming to find new and improved treatment modalities for CRC that can potentially increase survival and decrease overall morbidity and mortality. Current management strategies for CRC include surgical procedures for resectable cases, and radiotherapy, chemotherapy, and immunotherapy, in addition to their combination, for non-resectable tumors. Despite these options, CRC remains incurable in 50% of cases. Nonetheless, significant improvements in research techniques have allowed for treatment approaches for CRC to be frequently updated, leading to the availability of new drugs and therapeutic strategies. This review summarizes the most recent therapeutic approaches for CRC, with special emphasis on new strategies that are currently being studied and have great potential to improve the prognosis and lifespan of patients with CRC.

NXPH4 can be used as a biomarker for pan-cancer and promotes colon cancer progression

NXPH4 promotes cancer proliferation and invasion. However, its specific role and mechanism in cancer remain unclear. Transcriptome and clinical data for pan-cancer were derived from the TCGA database. K-M survival curve and univariate Cox were used for prognostic analysis. CIBERSORT and TIMER algorithms were employed to calculate immune cell infiltration. Gene set enrichment analysis (GSEA) was employed for investigating the function of NXPH4. Western blot verified differential expression of NXPH4 in colon cancer. Functional assays (CCK-8, plate clonogenicity assay, wound healing assay, and Transwell assay) confirmed the impact of NXPH4 on proliferation, invasion, and migration of colon cancer cells. Dysregulation of NXPH4 in pan-cancer suggests its potential as a diagnostic and prognostic marker for certain cancers, including colon and liver cancer. High expression of NXPH4 in pan-cancer might be associated with the increase in copy number and hypomethylation. NXPH4 expression in pan-cancer is substantially linked to immune cell infiltration in the immune microenvironment. NXPH4 expression is associated with the susceptibility to immunotherapy and chemotherapy. Western blot further confirmed the higher expression of NXPH4 in colon cancer. Knockdown of NXPH4 significantly suppresses proliferation, invasion, and migration of colon cancer cell lines HT-29 and HCT116, as validated by functional assays.

The C-type lectin DCIR contributes to the immune response and pathogenesis of colorectal cancer

Development and progression of malignancies are accompanied and influenced by alterations in the surrounding immune microenvironment. Understanding the cellular and molecular interactions between immune cells and cancer cells has not only provided important fundamental insights into the disease, but has also led to the development of new immunotherapies. The C-type lectin Dendritic Cell ImmunoReceptor (DCIR) is primarily expressed by myeloid cells and is an important regulator of immune homeostasis, as demonstrated in various autoimmune, infectious and inflammatory contexts. Yet, the impact of DCIR on cancer development remains largely unknown. Analysis of available transcriptomic data of colorectal cancer (CRC) patients revealed that high DCIR gene expression is associated with improved patients' survival, immunologically "hot" tumors and high immunologic constant of rejection, thus arguing for a protective and immunoregulatory role of DCIR in CRC. In line with these correlative data, we found that deficiency of DCIR1, the murine homologue of human DCIR, leads to the development of significantly larger tumors in an orthotopic murine model of CRC. This phenotype is accompanied by an altered phenotype of tumor-associated macrophages (TAMs) and a reduction in the percentage of activated effector CD4+ and CD8+ T cells in CRC tumors of DCIR1-deficient mice. Overall, our results show that DCIR promotes antitumor immunity in CRC, making it an attractive target for the future development of immunotherapies to fight the second deadliest cancer in the world.

Gemcitabine-loaded synthetic high-density lipoprotein preferentially eradicates hepatic monocyte-derived macrophages in mouse liver with colorectal cancer metastases

Liver metastasis of colorectal cancer (CRC) is the critical cause of CRC-related death due to its unique immunosuppressive microenvironment. In this study we generated a gemcitabine-loaded synthetic high-density lipoprotein (G-sHDL) to reverse immunosuppression in livers with CRC metastases. After intravenous injection, sHDL targeted hepatic monocyte-derived alternatively activated macrophages (Mono-M2) in the livers of mice bearing both subcutaneous tumors and liver metastases. The G-sHDL preferentially eradicated Mono-M2 in the livers with CRC metastases, which consequently prevented Mono-M2-mediated killing of tumor antigen-specific CD8+ T cells in the livers and thus improved the densities of tumor antigen-specific CD8+ T cells in the blood, tumor-draining lymph nodes and subcutaneous tumors of the treated mice. While reversing the immunosuppressive microenvironment, G-sHDL also induced immunogenic cell death of cancer cells, promoted maturation of dendritic cells, and increased tumor infiltration and activity of CD8+ T cells. Collectively, G-sHDL inhibited the growth of both subcutaneous tumors and liver metastases, and prolonged the survival of animals, which could be further improved when used in conjunction with anti-PD-L1 antibody. This platform can be a generalizable platform to modulate immune microenvironment of diseased livers.

Targeting the pericyte antigen DLK1 with an alpha type-1 polarized dendritic cell vaccine results in tumor vascular modulation and protection against colon cancer progression

Despite the availability of various treatment options, colorectal cancer (CRC) remains a significant contributor to cancer-related mortality. Current standard-of-care interventions, including surgery, chemotherapy, and targeted agents like immune checkpoint blockade and anti-angiogenic therapies, have improved short-term patient outcomes depending on disease stage, but survival rates with metastasis remain low. A promising strategy to enhance the clinical experience with CRC involves the use of dendritic cell (DC) vaccines that incite immunity against tumor-derived blood vessels, which are necessary for CRC growth and progression. In this report, we target tumor-derived pericytes expressing DLK1 with a clinically-relevant alpha type-1 polarized DC vaccine (αDC1) in a syngeneic mouse model of colorectal cancer. Our pre-clinical data demonstrate the αDC1 vaccine's ability to induce anti-tumor effects by facilitating cytotoxic T lymphocyte activity and ablating the tumor vasculature. This work, overall, provides a foundation to further interrogate immune-mediated mechanisms of protection in order to help devise efficacious αDC1-based strategies for patients with CRC.

TCR-independent CD137 (4-1BB) signaling promotes CD8+-exhausted T cell proliferation and terminal differentiation

CD137 (4-1BB)-activating receptor represents a promising cancer immunotherapeutic target. Yet, the cellular program driven by CD137 and its role in cancer immune surveillance remain unresolved. Using T cell-specific deletion and agonist antibodies, we found that CD137 modulates tumor infiltration of CD8+-exhausted T (Tex) cells expressing PD1, Lag-3, and Tim-3 inhibitory receptors. T cell-intrinsic, TCR-independent CD137 signaling stimulated the proliferation and the terminal differentiation of Tex precursor cells through a mechanism involving the RelA and cRel canonical NF-κB subunits and Tox-dependent chromatin remodeling. While Tex cell accumulation induced by prophylactic CD137 agonists favored tumor growth, anti-PD1 efficacy was improved with subsequent CD137 stimulation in pre-clinical mouse models. Better understanding of T cell exhaustion has crucial implications for the treatment of cancer and infectious diseases. Our results identify CD137 as a critical regulator of Tex cell expansion and differentiation that holds potential for broad therapeutic applications.

Circulating interleukins and risk of colorectal cancer: a Mendelian randomization study

BACKGROUND

Recent studies have suggested a potential causal association between Interleukins (ILs) and Colorectal Cancer (CRC), and thus, it is important to examine the causal relationship between them using a Mendelian randomization (MR) approach.

METHODS

The instrumental variables were extracted for IL-1ra, IL-6, IL-6ra, IL-8, IL-16, IL-18, IL-27 from genome-wide association studies of European ancestry. Summary statistics of CRC were also retrieved. An inverse variance-weighted MR approach was implemented as the primary method to compute overall effects from multiple instruments. Additional MR approaches and sensitivity and heterogeneity pleiotropy analyses were also conducted respectively.

RESULTS

Our analysis suggested a causal effect between an increase of IL-8 and a reduced risk of CRC (odds ratio 0.65; 95% confidence interval, 0.43-0.98; p = 0.041) and did not provide evidence for causal effects of IL-1ra, IL-6, IL-6ra, IL-16, IL-18, IL-27. Sensitivity analyses suggested the robustness of MR results and that they were unlikely to be affected by unbalanced pleiotropy or significant heterogeneity.

CONCLUSIONS

This study investigated the role of ILs in the development of CRC and we found a causal effect between an increase of IL-8 and a reduced risk of CRC but not found evidence for causal effects of IL-1ra, IL-6, IL-6ra, IL-16, IL-18, IL-27. Sensitivity analyses suggested the robustness of MR results and that they were unlikely to be affected by unbalanced pleiotropy or significant heterogeneity.

Distant antimetastatic effect of enterotropic colon cancer-derived α4β7+CD8+ T cells

Despite the high prognostic value of immune infiltrates in colorectal cancer (CRC), metastatic disease remains resistant to immunotherapy by immune checkpoint blockade (ICB). Here, we show, in metastatic CRC preclinical models, that orthotopically implanted primary colon tumors exert a colon-specific antimetastatic effect on distant hepatic lesions. Enterotropic α4β7 integrin-expressing neoantigen-specific CD8 T cells were key components of the antimetastatic effect. Accordingly, the presence of concomitant colon tumors improved control of liver lesions by anti-PD-L1 proof-of-concept immunotherapy and generated protective immune memory, whereas partial depletion of α4β7⁺ cells abrogated control of metastases. Last, in patients with metastatic CRC, response to ICB was associated with expression of α4β7 integrin in metastases and with circulating α4β7⁺ CD8 T cells. Our findings identify a systemic cancer immunosurveillance role for gut-primed tumor-specific α4β7⁺ CD8 T cells.

Notch3 signaling promotes colorectal tumor growth by enhancing immunosuppressive cells infiltration in the microenvironment

BACKGROUND

Macrophage infiltration in the tumor microenvironment participates in the regulation of tumor progression. Previous studies have found that Notch signaling pathway is involved in regulating the progression of colorectal cancer (CRC), however, the specific mechanism is still unclear.

METHODS

The correlation between Notch signaling pathway and macrophage infiltration was investigated in TCGA database and verified in clinical samples of patients with CRC using immunohistochemistry. Gene Set Enrichment Analysis was used to find out genes related to Notch3 expression. Colony formation assay, and flow cytometry were utilized to test tumor growth and immune cell infiltration in vitro and in vivo.

RESULTS

Using bioinformatics analysis and clinical sample validation, we found that Notch3 was highly expressed in colon tumor tissues compared to adjacent normal tissues, and it participated in regulating the recruitment of macrophages to the tumor microenvironment. Furthermore, we found that the Notch3 expression was positively correlated with the expression of macrophage recruitment-related cytokines in colon tumor tissues. Finally, we demonstrated that depletion of Notch3 had no significant effect on the growth of colon tumor cells in vitro, while, attenuated the growth of colon cancer tumors in vivo. Simultaneous, immunosuppressive cells, macrophages and myeloid-derived suppressor cell (MDSC) infiltration were dramatically reduced in the tumor microenvironment.

CONCLUSION

Our study illustrated that Notch3 could facilitate the progression of CRC by increasing the infiltration of macrophages and MDSCs to promote the immunosuppressive tumor microenvironment. Targeting Notch3 specifically is a potentially effective treatment for CRC.

Impact of mouse model tumor implantation site on acquired resistance to anti-PD-1 immune checkpoint therapy

Introduction

The use of tumor subcutaneous (SC) implantations rather than orthotopic sites is likely to induce a significant bias, in particular, in the field of immunotherapy.

Methods

In this study, we developed and characterized MC38 models, implanted subcutaneously and orthotopically, which were either sensitive or rendered resistant to anti-PD1 therapy. We characterized the tumor immune infiltrate by flow cytometry at baseline and after treatment.

Results and Discussion

Our results demonstrate several differences between SC and orthotopic models at basal state, which tend to become similar after therapy. These results emphasize the need to take into account tumor implantation sites when performing preclinical studies with immunotherapeutic agents.

Tumour microenvironment in pheochromocytoma and paraganglioma

Pheochromocytomas and Paragangliomas (Pheo/PGL) are rare catecholamine-producing tumours derived from adrenal medulla or from the extra-adrenal paraganglia respectively. Around 10-15% of Pheo/PGL develop metastatic forms and have a poor prognosis with a 37% of mortality rate at 5 years. These tumours have a strong genetic determinism, and the presence of succinate dehydrogenase B (SDHB) mutations are highly associated with metastatic forms. To date, no effective treatment is present for metastatic forms. In addition to cancer cells, the tumour microenvironment (TME) is also composed of non-neoplastic cells and non-cellular components, which are essential for tumour initiation and progression in multiple cancers, including Pheo/PGL. This review, for the first time, provides an overview of the roles of TME cells such as cancer-associated fibroblasts (CAFs) and tumour-associated macrophages (TAMs) on Pheo/PGL growth and progression. Moreover, the functions of the non-cellular components of the TME, among which the most representatives are growth factors, extracellular vesicles and extracellular matrix (ECM) are explored. The importance of succinate as an oncometabolite is emerging and since Pheo/PGL SDH mutated accumulate high levels of succinate, the role of succinate and of its receptor (SUCNR1) in the modulation of the carcinogenesis process is also analysed. Further understanding of the mechanism behind the complicated effects of TME on Pheo/PGL growth and spread could suggest novel therapeutic targets for further clinical treatments.

Predictive biomarkers of colon cancer immunotherapy: Present and future

Immunotherapy has revolutionized colon cancer treatment. Immune checkpoint inhibitors (ICIs) have shown clinical benefits for colon cancer patients, especially those with high microsatellite instability (MSI-H). In 2020, the US Food and Drug Administration (FDA)-approved ICI pembrolizumab as the first-line treatment for metastatic MSI-H colon cancer patients. Additionally, neoadjuvant immunotherapy has presented efficacy in treating early-stage colon cancer patients. Although MSI has been thought of as an effective predictive biomarker for colon cancer immunotherapy, only a small proportion of colon cancer patients were MSI-H, and certain colon cancer patients with MSI-H presented intrinsic or acquired resistance to immunotherapy. Thus, further search for predictive biomarkers to stratify patients is meaningful in colon cancer immunotherapy. Except for MSI, other biomarkers, such as PD-L1 expression level, tumor mutation burden (TMB), tumor-infiltrating lymphocytes (TILs), certain gut microbiota, ctDNA, and circulating immune cells were also proposed to be correlated with patient survival and ICI efficacy in some colon cancer clinical studies. Moreover, developing new diagnostic techniques helps identify accurate predictive biomarkers for colon cancer immunotherapy. In this review, we outline the reported predictive biomarkers in colon cancer immunotherapy and further discuss the prospects of technological changes for biomarker development in colon cancer immunotherapy.

Comprehensive Analysis of Necroptosis-Related Long Noncoding RNA Immune Infiltration and Prediction of Prognosis in Patients With Colon Cancer

Colon cancer (CC) is one of the most frequent malignancies in the world, with a high rate of morbidity and death. In CC, necroptosis and long noncoding RNA (lncRNAs) are crucial, but the mechanism is not completely clear. The goal of this study was to create a new signature that might predict patient survival and tumor immunity in patients with CC. Expression profiles of necroptosis-related lncRNAs in 473 patients with CC were retrieved from the TCGA database. A consensus clustering analysis based on differentially expressed (DE) genes and a prognostic model based on least absolute shrinkage and selection operator (LASSO) regression analysis were conducted. Clinicopathological correlation analysis, expression difference analysis, PCA, TMB, GO analysis, KEGG enrichment analysis, survival analysis, immune correlation analysis, prediction of clinical therapeutic compounds, and qRT–PCR were also conducted. Fifty-six necroptosis-related lncRNAs were found to be linked to the prognosis, and consensus clustering analysis was performed. There were substantial variations in survival, immune checkpoint expression, clinicopathological correlations, and tumor immunity among the different subgroups. Six lncRNAs were discovered, and patients were split into high-risk and low-risk groups based on a risk score generated using these six lncRNAs. The survival time of low-risk patients was considerably longer than that of high-risk patients, indicating that these lncRNAs are directly associated with survival. The risk score was associated with the tumor stage, infiltration depth, lymph node metastasis, and distant metastasis. After univariate and multivariate Cox regression analysis, the risk score and tumor stage remained significant. Cancer- and metabolism-related pathways were enriched by KEGG analyses. Immune infiltration was shown to differ significantly between high- and low-risk patients in a tumor immunoassay. Eight compounds were screened out, and qRT–PCR confirmed the differential expression of the six lncRNAs. Overall, in CC, necroptosis-related lncRNAs have an important function, and the prognosis of patients with CC can be predicted by these six necroptosis-related lncRNAs. They may be useful in the future for customized cancer therapy.

FUT7 Promotes the Epithelial-Mesenchymal Transition and Immune Infiltration in Bladder Urothelial Carcinoma

Background

Bladder urothelial carcinoma (BLCA) is one of the most frequently appearing, lethal and aggressive malignancies of the genitourinary system with growing morbidity and mortality, which affects human health seriously. Protein glycosylation, catalyzed by specific glycosyltransferase, has been found to be abnormal in several diseases, especially cancer. Fucosyltransferase VII (FUT7), one of the fucosyltransferases, was observed abnormally expressed in various cancers, however, the role of FUT7 in BLCA, and the association between its expression and clinical outcomes or immune infiltration remains unclear.

Methodology

FUT7 expression in BLCA was analyzed in Oncomine database, which was further confirmed with immunohistochemistry and ELISA. The prognostic value of FUT7 for BLCA was evaluated with PrognoScan database, and its genetic alteration was examined in cBioPortal database. The proliferation, migration, invasion and epithelial–mesenchymal transition (EMT) changes of bladder cancer cells after FUT7 siRNA or cDNA transfection were determined by CCK8, colony formation, transwell and Western blot, respectively. The correlation between FUT7 expression and immune infiltration levels was analyzed in TIMER and TISIDB databases, and the methylation level of FUT7 was detected in UALCAN database.

Results

The results showed that the expression of FUT7 was increased in BLCA, and patients with high FUT7 level were predicted to have lower overall survival and disease-specific survival rates, which were not influenced by FUT7 genetic alterations. Downregulation FUT7 inhibited the proliferation, migration, invasion and EMT of bladder cancer cells, whereas upregulation of FUT7 showed the opposite effects. We found that FUT7 was positively correlated with immune cell infiltration levels (CD8+ T cells, CD4+T cells, macrophage, neutrophil and dendritic cells), and also the expression of gene markers of immune cells. The negative correlation between FUT7 expression and FUT7 methylation level was observed, among which FUT7 expression was positively correlated with the abundance of 28 kinds of tumor-infiltrating lymphocytes (TILs), while FUT7 methylation level was negatively correlated with TILs.

Conclusion

Altogether, these findings suggested that FUT7 possessed the potential to serve as a detection biomarker or immunotherapeutic target for BLCA.

Emerging Trends for Radio-Immunotherapy in Rectal Cancer

Rectal cancer is a heterogeneous disease at the genetic and molecular levels, both aspects having major repercussions on the tumor immune contexture. Whilst microsatellite status and tumor mutational load have been associated with response to immunotherapy, presence of tumor-infiltrating lymphocytes is one of the most powerful prognostic and predictive biomarkers. Yet, the majority of rectal cancers are characterized by microsatellite stability, low tumor mutational burden and poor T cell infiltration. Consequently, these tumors do not respond to immunotherapy and treatment largely relies on radiotherapy alone or in combination with chemotherapy followed by radical surgery. Importantly, pre-clinical and clinical studies suggest that radiotherapy can induce a complete reprograming of the tumor microenvironment, potentially sensitizing it for immune checkpoint inhibition. Nonetheless, growing evidence suggest that this synergistic effect strongly depends on radiotherapy dosing, fractionation and timing. Despite ongoing work, information about the radiotherapy regimen required to yield optimal clinical outcome when combined to checkpoint blockade remains largely unavailable. In this review, we describe the molecular and immune heterogeneity of rectal cancer and outline its prognostic value. In addition, we discuss the effect of radiotherapy on the tumor microenvironment, focusing on the mechanisms and benefits of its combination with immune checkpoint inhibitors.