Macrophage-derived CCL5 facilitates immune escape of colorectal cancer cells via the p65/STAT3-CSN5-PD-L1 pathway

The role of innate immune cells in the colorectal cancer tumor microenvironment and advances in anti-tumor therapy research

Innate immune cells in the colorectal cancer microenvironment mainly include macrophages, neutrophils, natural killer cells, dendritic cells and bone marrow-derived suppressor cells. They play a pivotal role in tumor initiation and progression through the secretion of diverse cytokines, chemokines, and other factors that govern these processes. Colorectal cancer is a common malignancy of the gastrointestinal tract, and understanding the role of innate immune cells in the microenvironment of CRC may help to improve therapeutic approaches to CRC and increase the good prognosis. In this review, we comprehensively explore the pivotal role of innate immune cells in the initiation and progression of colorectal cancer (CRC), alongside an extensive evaluation of the current landscape of innate immune cell-based immunotherapies, thereby offering valuable insights for future research strategies and clinical trials.

New horizons in the mechanisms and therapeutic strategies for PD-L1 protein degradation in cancer

Programmed death-ligand 1 (PD-L1) has become a crucial focus in cancer immunotherapy considering it is found in many different cells. Cancer cells enhance the suppressive impact of programmed death receptor 1 (PD-1) through elevating PD-L1 expression, which allows them to escape immune detection. Although there have been significant improvements, the effectiveness of anti-PD-1/PD-L1 treatment is still limited to a specific group of patients. An important advancement in cancer immunotherapy involves improving the PD-L1 protein degradation. This review thoroughly examined the processes by which PD-L1 breaks down, including the intracellular pathways of ubiquitination-proteasome and autophagy-lysosome. In addition, the analysis revealed changes that affect PD-L1 stability, such as phosphorylation and glycosylation. The significant consequences of these procedures on cancer immunotherapy and their potential role in innovative therapeutic approaches are emphasised. Our future efforts will focus on understanding new ways in which PD-L1 degradation is controlled and developing innovative treatments, such as proteolysis-targeting chimeras designed specifically to degrade PD-L1. It is crucial to have a thorough comprehension of these pathways in order to improve cancer immunotherapy strategies and hopefully improve therapeutic effectiveness.

SOX17: escape route from immune destruction in early CRC

In a recent report in Nature, Goto et al. reveal a novel immune-evasion mechanism adopted by early colorectal cancer (CRC) cells that is based on the transcription factor sex determining region Y (SRY)-box transcription factor 17 (SOX17). Leveraging colorectal adenoma and cancer models to perform comprehensive transcriptomic/chromatin analyses, this work shows that SOX17 generates immune-silent leucine-rich repeat-containing G protein-coupled receptor 5- (LGR5-) tumor cells, which suppress interferon gamma (IFNγ) signaling and promote immune escape.

Microbial metabolites affect tumor progression, immunity and therapy prediction by reshaping the tumor microenvironment (Review)

Several studies have indicated that the gut microbiome and tumor microbiota may affect tumors. Emerging metabolomics research illustrates the need to examine the variations in microbial metabolite composition between patients with cancer and healthy individuals. Microbial metabolites can impact the progression of tumors and the immune response by influencing a number of mechanisms, including modulation of the immune system, cancer or immune‑related signaling pathways, epigenetic modification of proteins and DNA damage. Microbial metabolites can also alleviate side effects and drug resistance during chemotherapy and immunotherapy, while effectively activating the immune system to exert tumor immunotherapy. Nevertheless, the impact of microbial metabolites on tumor immunity can be both beneficial and harmful, potentially influenced by the concentration of the metabolites or the specific cancer type. The present review summarizes the roles of various microbial metabolites in different solid tumors, alongside their influence on tumor immunity and treatment. Additionally, clinical trials evaluating the therapeutic effects of microbial metabolites or related microbes on patients with cancer have been listed. In summary, studying microbial metabolites, which play a crucial role in the interaction between the microbiota and tumors, could lead to the identification of new supplementary treatments for cancer. This has the potential to improve the effectiveness of cancer treatment and enhance patient prognosis.

Regulation of post-translational modification of PD-L1 and associated opportunities for novel small-molecule therapeutics

PD-L1 is overexpressed on the surface of tumor cells and binds to PD-1, resulting in tumor immune escape. Therapeutic strategies to target the PD-1/PD-L1 pathway involve blocking the binding. Immune checkpoint inhibitors have limited efficacy against tumors because PD-L1 is also present in the cytoplasm. PD-L1 of post-translational modifications (PTMs) have uncovered numerous mechanisms contributing to carcinogenesis and have identified potential therapeutic targets. Therefore, small molecule inhibitors can block crucial carcinogenic signaling pathways, making them a potential therapeutic option. To better develop small molecule inhibitors, we have summarized the PTMs of PD-L1. This review discusses the regulatory mechanisms of small molecule inhibitors in carcinogenesis and explore their potential applications, proposing a novel approach for tumor immunotherapy based on PD-L1 PTM.

EZH2 Inhibition Enhances PD-L1 Protein Stability Through USP22-Mediated Deubiquitination in Colorectal Cancer

The regulation of PD-L1 is the key question, which largely determines the outcome of the immune checkpoint inhibitors (ICIs) based therapy. However, besides the transcription level, the protein stability of PD-L1 is closely correlated with its function and has drawn increasing attention. In this study, EZH2 inhibition enhances PD-L1 expression and protein stability, and the deubiquitinase ubiquitin-specific peptidase 22 (USP22) is identified as a key mediator in this process. EZH2 inhibition transcriptionally upregulates USP22 expression, and upregulated USP22 further stabilizes PD-L1. Importantly, a combination of EZH2 inhibitors with anti-PD-1 immune checkpoint blockade therapy improves the tumor microenvironment, enhances sensitivity to immunotherapy, and exerts synergistic anticancer effects. In addition, knocking down USP22 can potentially enhance the therapeutic efficacy of EZH2 inhibitors on colon cancer. These findings unveil the novel role of EZH2 inhibitors in tumor immune evasion by upregulating PD-L1, and this drawback can be compensated by combining ICI immunotherapy. Therefore, these findings provide valuable insights into the EZH2-USP22-PD-L1 regulatory axis, shedding light on the optimization of combining both immune checkpoint blockade and EZH2 inhibitor-based epigenetic therapies to achieve more efficacies and accuracy in cancer treatment.

Arenobufagin modulation of PCSK9-mediated cholesterol metabolism induces tumor-associated macrophages polarisation to inhibit hepatocellular carcinoma progression

BACKGROUND

The tumor microenvironment (TME) of hepatocellular carcinoma is heterogeneous enough to be prone to drug resistance and multidrug resistance during treatment, and reprogramming of cholesterol metabolism in TME mediates tumor-associated macrophages (TAMs) polarization, which has an impact on the regulation of malignant tumor progression. Arenobufagin (ARBU) was extracted and isolated from toad venom (purity ≥98 %), which is the main active ingredient of the traditional Chinese medicine Chan'su with good anti-tumor effects.

PURPOSE

To investigate the regulatory effect of ARBU on lipid metabolism in tumor microenvironment, interfere with macrophage polarization, and determine its mechanism of action on liver cancer progression.

METHODS

In this study, the inhibitory effect of ARBU on the proliferation of Hepa1-6 in C57 mice and the safety of administration were evaluated by establishing a transplanted tumor model of Hepa1-6 hepatocellular carcinoma mice and using 5-FU as a positive control drug. In addition, we constructed a co-culture system of Hepa1-6 cells and primary mouse macrophages to study the effects of ARBU on the polarization phenotypic transformation of macrophages and the proliferation and migration of hepatoma cells. The influence of ARBU on the metabolism of lipids in the hepatocellular carcinoma mouse model was investigated by combining it with lipidomics technology. The influence of ARBU on the PCSK9/LDL-R signaling pathway and macrophage polarization, which regulate cholesterol metabolism, was tested by using qRT-PCR, gene editing, IF, and WB.

CONCLUSION

ARBU significantly inhibited the proliferation of Hepa1-6 in vivo and in vitro, regulated cholesterol metabolism, and promoted the M1-type polarization of macrophages in the tumor microenvironment. ARBU inhibits cholesterol synthesis in the TME through the PCSK9/LDL-R signaling pathway, thereby blocking macrophage M2 polarization, promoting apoptosis of the tumor cells, and inhibiting their proliferation and migration.

PD-1/PD-L1 axis is involved in the interaction between microglial polarization and glioma

The tumor microenvironment plays a vital role in glioblastoma growth and invasion. PD-1 and PD-L1 modulate the immunity in the brain tumor microenvironment. However, the underlying mechanisms remain unclear. In the present study, in vivo and in vitro experiments were conducted to reveal the effects of PD-1/PD-L1 on the crosstalk between microglia and glioma. Results showed that glioma cells secreted PD-L1 to the peritumoral areas, particularly microglia containing highly expressed PD-1. In the early stages of glioma, microglia mainly polarized into the pro-inflammatory subtype (M1). Subsequently, the secreted PD-L1 accumulated and bound to PD-1 on microglia, facilitating their polarization toward the microglial anti-inflammatory (M2) subtype primarily via the STAT3 signaling pathway. The role of PD-1/PD-L1 in M2 polarization of microglia was partially due to PD-1/PD-L1 depletion or application of BMS-1166, a novel inhibitor of PD-1/PD-L1. Consistently, co-culturing with microglia promoted glioma cell growth and invasion, and blocking PD-1/PD-L1 significantly suppressed these processes. Our findings reveal that the PD-1/PD-L1 axis engages in the microglial M2 polarization in the glioma microenvironment and promotes tumor growth and invasion.

Synergistic Immunoregulation: harnessing CircRNAs and PiRNAs to Amplify PD-1/PD-L1 Inhibition Therapy

The utilization of PD-1/PD-L1 inhibitors marks a significant advancement in cancer therapy. However, the efficacy of monotherapy is still disappointing in a substantial subset of patients, necessitating the exploration of combinational strategies. Emerging from the promising results of the KEYNOTE-942 trial, RNA-based therapies, particularly circRNAs and piRNAs, have distinguished themselves as innovative sensitizers to immune checkpoint inhibitors (ICIs). These non-coding RNAs, notable for their stability and specificity, were once underrecognized but are now known for their crucial roles in regulating PD-L1 expression and bolstering anti-cancer immunity. Our manuscript offers a comprehensive analysis of selected circRNAs and piRNAs, elucidating their immunomodulatory effects and mechanisms, thus underscoring their potential as ICIs enhancers. In conjunction with the recent Nobel Prize-awarded advancements in mRNA vaccine technology, our review highlights the transformative implications of these findings for cancer treatment. We also discuss the prospects of circRNAs and piRNAs in future therapeutic applications and research. This study pioneers the synergistic application of circRNAs and piRNAs as novel sensitizers to augment PD-1/PD-L1 inhibition therapy, demonstrating their unique roles in regulating PD-L1 expression and modulating immune responses. Our findings offer a groundbreaking approach for enhancing the efficacy of cancer immunotherapy, opening new avenues for treatment strategies. This abstract aims to encapsulate the essence of our research and the burgeoning role of these non-coding RNAs in enhancing PD-1/PD-L1 inhibition therapy, encouraging further investigation into this promising field.

The crosstalk between macrophages and cancer cells potentiates pancreatic cancer cachexia

With limited treatment options, cachexia remains a major challenge for patients with cancer. Characterizing the interplay between tumor cells and the immune microenvironment may help identify potential therapeutic targets for cancer cachexia. Herein, we investigate the critical role of macrophages in potentiating pancreatic cancer induced muscle wasting via promoting TWEAK (TNF-like weak inducer of apoptosis) secretion from the tumor. Specifically, depletion of macrophages reverses muscle degradation induced by tumor cells. Macrophages induce non-autonomous secretion of TWEAK through CCL5/TRAF6/NF-κB pathway. TWEAK promotes muscle atrophy by activating MuRF1 initiated muscle remodeling. Notably, tumor cells recruit and reprogram macrophages via the CCL2/CCR2 axis and disrupting the interplay between macrophages and tumor cells attenuates muscle wasting. Collectively, this study identifies a feedforward loop between pancreatic cancer cells and macrophages, underlying the non-autonomous activation of TWEAK secretion from tumor cells thereby providing promising therapeutic targets for pancreatic cancer cachexia.

COP9 signalosome component CSN-5 stabilizes PUF proteins FBF-1 and FBF-2 in Caenorhabditis elegans germline stem and progenitor cells

RNA-binding proteins FBF-1 and FBF-2 (FBFs) are required for germline stem cell maintenance and the sperm/oocyte switch in Caenorhabditis elegans, although the mechanisms controlling FBF protein levels remain unknown. We identified an interaction between both FBFs and CSN-5), a component of the constitutive photomorphogenesis 9 (COP9) signalosome best known for its role in regulating protein degradation. Here, we find that the Mpr1/Pad1 N-terminal metalloprotease domain of CSN-5 interacts with the Pumilio and FBF RNA-binding domain of FBFs and the interaction is conserved for human homologs CSN5 and PUM1. The interaction between FBF-2 and CSN-5 can be detected in vivo by proximity ligation. csn-5 mutation results in the destabilization of FBF proteins, which may explain previously observed decrease in the numbers of germline stem and progenitor cells, and disruption of oogenesis. The loss of csn-5 does not decrease the levels of a related PUF protein PUF-3, and csn-5(lf) phenotype is not enhanced by fbf-1/2 knockdown, suggesting that the effect is specific to FBFs. The effect of csn-5 on oogenesis is largely independent of the COP9 signalosome and is cell autonomous. Surprisingly, the regulation of FBF protein levels involves a combination of COP9-dependent and COP9-independent mechanisms differentially affecting FBF-1 and FBF-2. This work supports a previously unappreciated role for CSN-5 in the stabilization of germline stem cell regulatory proteins FBF-1 and FBF-2.

E4BP4 in macrophages induces an anti-inflammatory phenotype that ameliorates the severity of colitis

Macrophages are versatile cells of the innate immune system that work by altering their pro- or anti-inflammatory features. Their dysregulation leads to inflammatory disorders such as inflammatory bowel disease. We show that macrophage-specific upregulation of the clock output gene and transcription factor E4BP4 reduces the severity of colitis in mice. RNA-sequencing and single-cell analyses of macrophages revealed that increased expression of E4BP4 leads to an overall increase in expression of anti-inflammatory genes including Il4ra with a concomitant reduction in pro-inflammatory gene expression. In contrast, knockout of E4BP4 in macrophages leads to increased proinflammatory gene expression and decreased expression of anti-inflammatory genes. ChIP-seq and ATAC-seq analyses further identified Il4ra as a target of E4BP4, which drives anti-inflammatory polarization in macrophages. Together, these results reveal a critical role for E4BP4 in regulating macrophage inflammatory phenotypes and resolving inflammatory bowel diseases.

Obesity and early-onset colorectal cancer risk: emerging clinical evidence and biological mechanisms

Early-onset colorectal cancer (EOCRC) is defined as diagnosed at younger than 50 years of age and indicates a health burden globally. Patients with EOCRC have distinct risk factors, clinical characteristics, and molecular pathogenesis compared with older patients with CRC. Further investigations have identified different roles of obesity between EOCRC and late-onset colorectal cancer (LOCRC). Most studies have focused on the clinical characteristics of obesity in EOCRC, therefore, the mechanism involved in the association between obesity and EOCRC remains inconclusive. This review further states that obesity affects the carcinogenesis of EOCRC as well as its development and progression, which may lead to obesity-related metabolic syndrome, intestinal dysbacteriosis, and intestinal inflammation.

The endonuclease FEN1 mediates activation of STAT3 and facilitates proliferation and metastasis in breast cancer

BACKGROUND

The metastasis accounts for most deaths from breast cancer (BRCA). Understanding the molecular mechanisms of BRCA metastasis is urgently demanded. Flap Endonuclease 1 (FEN1), a pivotal factor in DNA metabolic pathways, contributes to tumor growth and drug resistance, however, little is known about the role of FEN1 in BRCA metastasis.

METHODS AND RESULTS

In this study, FEN1 expression and its clinical correlation in BRCA were investigated using bioinformatics, showing being upregulated in BRCA samples and significant relationships with tumor stage, node metastasis, and prognosis. Immunohistochemistry (IHC) staining of local BRCA cohort indicated that the ratio of high FEN1 expression in metastatic BRCA tissues rose over that in non-metastatic tissues. The assays of loss-of-function and gain-of-function showed that FEN1 enhanced BRCA cell proliferation, migration, invasion, xenograft growth as well as lung metastasis. It was further found that FEN1 promoted the aggressive behaviors of BRCA cells via Signal Transducer and Activator of Transcription 3 (STAT3) activation. Specifically, the STAT3 inhibitor Stattic thwarted the FEN1-induced enhancement of migration and invasion, while the activator IL-6 rescued the decreased migration and invasion caused by FEN1 knockdown. Additionally, overexpression of FEN1 rescued the inhibitory effect of nuclear factor-κB (NF-κB) inhibitor BAY117082 on phosphorylated STAT3. Simultaneously, the knockdown of FEN1 attenuated the phosphorylation of STAT3 promoted by the NF-κB activator tumor necrosis factor α (TNF-α).

CONCLUSIONS

These results indicate a novel mechanism that NF-κB-driven FEN1 contributes to promoting BRCA growth and metastasis by STAT3 activation.

A2AR-mediated CXCL5 upregulation on macrophages promotes NSCLC progression via NETosis

Tumor-associated macrophages (TAMs) are abundant in tumors and interact with tumor cells, leading to the formation of an immunosuppressive microenvironment and tumor progression. Although many studies have explored the mechanisms underlying TAM polarization and its immunosuppressive functions, understanding of its progression remains limited. TAMs promote tumor progression by secreting cytokines, which subsequently recruit immunosuppressive cells to suppress the antitumor immunity. In this study, we established an in vitro model of macrophage and non-small cell lung cancer (NSCLC) cell co-culture to explore the mechanisms of cell-cell crosstalk. We observed that in NSCLC, the C-X-C motif chemokine ligand 5 (CXCL5) was upregulated in macrophages because of the stimulation of A2AR by adenosine. Adenosine was catalyzed by CD39 and CD73 in macrophages and tumor cells, respectively. Nuclear factor kappa B (NFκB) mediated the A2AR stimulation of CXCL5 upregulation in macrophages. Additionally, CXCL5 stimulated NETosis in neutrophils. Neutrophil extracellular traps (NETs)-treated CD8+ T cells exhibited upregulation of exhaustion-related and cytosolic DNA sensing pathways and downregulation of effector-related genes. However, A2AR inhibition significantly downregulated CXCL5 expression and reduced neutrophil infiltration, consequently alleviating CD8+ T cell dysfunction. Our findings suggest a complex interaction between tumor and immune cells and its potential as therapeutic target.

The role of CXCL2-mediated crosstalk between tumor cells and macrophages in Fusobacterium nucleatum-promoted oral squamous cell carcinoma progression

Dysbiosis of the oral microbiota is related to chronic inflammation and carcinogenesis. Fusobacterium nucleatum (Fn), a significant component of the oral microbiota, can perturb the immune system and form an inflammatory microenvironment for promoting the occurrence and progression of oral squamous cell carcinoma (OSCC). However, the underlying mechanisms remain elusive. Here, we investigated the impacts of Fn on OSCC cells and the crosstalk between OSCC cells and macrophages. 16 s rDNA sequencing and fluorescence in situ hybridization verified that Fn was notably enriched in clinical OSCC tissues compared to paracancerous tissues. The conditioned medium co-culture model validated that Fn and macrophages exhibited tumor-promoting properties by facilitating OSCC cell proliferation, migration, and invasion. Besides, Fn and OSCC cells can recruit macrophages and facilitate their M2 polarization. This crosstalk between OSCC cells and macrophages was further enhanced by Fn, thereby amplifying this positive feedback loop between them. The production of CXCL2 in response to Fn stimulation was a significant mediator. Suppression of CXCL2 in OSCC cells weakened Fn's promoting effects on OSCC cell proliferation, migration, macrophage recruitment, and M2 polarization. Conversely, knocking down CXCL2 in macrophages reversed the Fn-induced feedback effect of macrophages on the highly invasive phenotype of OSCC cells. Mechanistically, Fn activated the NF-κB pathway in both OSCC cells and macrophages, leading to the upregulation of CXCL2 expression. In addition, the SCC7 subcutaneous tumor-bearing model in C3H mice also substantiated Fn's ability to enhance tumor progression by facilitating cell proliferation, activating NF-κB signaling, up-regulating CXCL2 expression, and inducing M2 macrophage infiltration. However, these effects were reversed by the CXCL2-CXCR2 inhibitor SB225002. In summary, this study suggests that Fn contributes to OSCC progression by promoting tumor cell proliferation, macrophage recruitment, and M2 polarization. Simultaneously, the enhanced CXCL2-mediated crosstalk between OSCC cells and macrophages plays a vital role in the pro-cancer effect of Fn.

Association between Metabolic Reprogramming and Immune Regulation in Digestive Tract Tumors

BACKGROUND

The cancers of the digestive tract, including colorectal cancer (CRC), gastric cancer, and esophageal cancer, are part of the most common cancers as well as one of the most important leading causes of cancer death worldwide.

SUMMARY

Despite the emergence of immune checkpoint inhibitors (e.g., anti-CTLA-4 and anti-PD-1/PD-L1) in the past decade, offering renewed optimism in cancer treatment, only a fraction of patients derive benefit from these therapies. This limited efficacy may stem from tumor heterogeneity and the impact of metabolic reprogramming on both tumor cells and immune cells within the tumor microenvironment (TME). The metabolic reprogramming of glucose, lipids, amino acids, and other nutrients represents a pivotal hallmark of cancer, serving to generate energy, reducing equivalent and biological macromolecule, thereby fostering tumor proliferation and invasion. Significantly, the metabolic reprogramming of tumor cells can orchestrate changes within the TME, rendering patients unresponsive to immunotherapy.

KEY MESSAGES

In this review, we predominantly encapsulate recent strides on metabolic reprogramming among digestive tract cancer, especially CRC, in the TME with a focus on how these alterations influence anti-tumor immunity. Additionally, we deliberate on potential strategies to address these abnormities in metabolic pathways and the viability of combined therapy within the realm of anti-cancer immunotherapy.

Chemotherapy-Enabled Colorectal Cancer Immunotherapy of Self-Delivery Nano-PROTACs by Inhibiting Tumor Glycolysis and Avoiding Adaptive Immune Resistance

The chemo-regulation abilities of chemotherapeutic medications are appealing to address the low immunogenicity, immunosuppressive lactate microenvironment, and adaptive immune resistance of colorectal cancer. In this work, the proteolysis targeting chimera (PROTAC) of BRD4 (dBET57) is found to downregulate colorectal cancer glycolysis through the transcription inhibition of c-Myc, which also inhibits the expression of programmed death ligand 1 (PD-L1) to reverse immune evasion and avoid adaptive immune resistance. Based on this, self-delivery nano-PROTACs (designated as DdLD NPs) are further fabricated by the self-assembly of doxorubicin (DOX) and dBET57 with the assistance of DSPE-PEG2000. DdLD NPs can improve the stability, intracellular delivery, and tumor targeting accumulation of DOX and dBET57. Meanwhile, the chemotherapeutic effect of DdLD NPs can efficiently destroy colorectal cancer cells to trigger a robust immunogenic cell death (ICD). More importantly, the chemo-regulation effects of DdLD NPs can inhibit colorectal cancer glycolysis to reduce the lactate production, and downregulate the PD-L1 expression through BRD4 degradation. Taking advantages of the chemotherapy and chemo-regulation ability, DdLD NPs systemically activated the antitumor immunity to suppress the primary and metastatic colorectal cancer progression without inducing any systemic side effects. Such self-delivery nano-PROTACs may provide a new insight for chemotherapy-enabled tumor immunotherapy.

Recent advances and mechanisms of action of PD-L1 degraders as potential therapeutic agents

PD-L1 is an important immune checkpoint protein that can bind to T cells' PD-1 receptor, thereby promoting immune escape from tumors. In recent years, many researchers have developed strategies to degrade PD-L1 to improve the effect of immunotherapy. The study of degrading PD-L1 provides new opportunities for immunotherapy. Here, we mainly summarize and review the current active molecules and mechanisms that mediate the degradation of immature and mature PD-L1 during the post-translational modification stages, involving PD-L1 phosphorylation, glycosylation, palmitoylation, ubiquitination, and the autophagy-lysosomal process. This review expects that by degrading PD-L1 protein, we will not only gain a better understanding of oncogenic mechanisms involving tumor PD-L1 protein but also provide a new way to improve immunotherapy.

LncRNA MEG3 Reduces the Ratio of M2/M1 Macrophages Through the HuR/CCL5 Axis in Hepatocellular Carcinoma

Objective

Tumor-associated macrophages play a crucial role in the development of hepatocellular carcinoma (HCC). Our study aimed to investigate the relationship between long coding RNA (lncRNA) maternally expressed gene 3 (MEG3), RNA-binding protein human antigen R (HuR), and messenger RNA C-C motif chemokine 5 (CCL5) in the modulation of M1 and M2 macrophage polarization in HCC.

Methods

To induce M1 or M2 polarization, LPS/IFNγ- or IL4/IL13 were used to treat bone marrow derived macrophages (BMDMs). The localization of MEG3 in M1 and M2 macrophages was assessed using fluorescence in situ hybridization assay. Expression levels of MEG3, HuR, CCL5, M1, and M2 markers were measured by RT-qPCR or immunofluorescence staining. Flow cytometry was performed to determine the proportion of F4/80+CD206+ and F4/80+CD68+ cells. RNA pulldown assay was performed to detect the binding of lncRNA MEG3 and HuR. The impacts of HuR on CCL5 stability and activity of CCL5 promoter were evaluated using actinomycin D treatment and luciferase reporter assay. Cell migration, invasiveness, and angiogenesis were assessed using transwell migration and invasion assays and a tube formation assay. A mixture of Huh-7 cells and macrophages were injected into nude mice to explore the effect of MEG3 on tumorigenesis.

Results

MEG3 promoted M1-like polarization while dampening M2-like polarization of BMDMs. MEG3 bound to HuR in M1 and M2 macrophages. HuR downregulated CCL5 by inhibiting CCL5 transcription in macrophages. In addition, overexpression of MEG3 suppressed cell metastasis, invasion, and angiogenesis by obstructing macrophage M2 polarization. MEG3 inhibited tumorigenesis in HCC via promotion of M1-like polarization and inhibition of M2-like polarization. Rescue experiments showed that depletion of CCL5 in M2 macrophages reversed MEG3-induced suppressive effect on cell migration, invasion, and tube formation.

Conclusion

MEG3 suppresses HCC progression by promoting M1-like while inhibiting M2-like macrophage polarization via binding to HuR and thus upregulating CCL5.

Effects of dietary intervention on human diseases: molecular mechanisms and therapeutic potential

Diet, serving as a vital source of nutrients, exerts a profound influence on human health and disease progression. Recently, dietary interventions have emerged as promising adjunctive treatment strategies not only for cancer but also for neurodegenerative diseases, autoimmune diseases, cardiovascular diseases, and metabolic disorders. These interventions have demonstrated substantial potential in modulating metabolism, disease trajectory, and therapeutic responses. Metabolic reprogramming is a hallmark of malignant progression, and a deeper understanding of this phenomenon in tumors and its effects on immune regulation is a significant challenge that impedes cancer eradication. Dietary intake, as a key environmental factor, can influence tumor metabolism. Emerging evidence indicates that dietary interventions might affect the nutrient availability in tumors, thereby increasing the efficacy of cancer treatments. However, the intricate interplay between dietary interventions and the pathogenesis of cancer and other diseases is complex. Despite encouraging results, the mechanisms underlying diet-based therapeutic strategies remain largely unexplored, often resulting in underutilization in disease management. In this review, we aim to illuminate the potential effects of various dietary interventions, including calorie restriction, fasting-mimicking diet, ketogenic diet, protein restriction diet, high-salt diet, high-fat diet, and high-fiber diet, on cancer and the aforementioned diseases. We explore the multifaceted impacts of these dietary interventions, encompassing their immunomodulatory effects, other biological impacts, and underlying molecular mechanisms. This review offers valuable insights into the potential application of these dietary interventions as adjunctive therapies in disease management.

TMEM160 promotes tumor immune evasion and radiotherapy resistance via PD-L1 binding in colorectal cancer

BACKGROUND

The effectiveness of anti-programmed cell death protein 1(PD-1)/programmed cell death 1 ligand 1(PD-L1) therapy in treating certain types of cancer is associated with the level of PD-L1. However, this relationship has not been observed in colorectal cancer (CRC), and the underlying regulatory mechanism of PD-L1 in CRC remains unclear.

METHODS

Binding of TMEM160 to PD-L1 was determined by co-immunoprecipitation (Co-IP) and GST pull-down assay.The ubiquitination levels of PD-L1 were verified using the ubiquitination assay. Phenotypic experiments were conducted to assess the role of TMEM160 in CRC cells. Animal models were employed to investigate how TMEM160 contributes to tumor growth.The expression and clinical significance of TMEM160 and PD-L1 in CRC tissues were evaluated by immunohistochemistry(IHC).

RESULTS

In our study, we made a discovery that TMEM160 interacts with PD-L1 and plays a role in stabilizing its expression within a CRC model. Furthermore, we demonstrated that TMEM160 hinders the ubiquitination-dependent degradation of PD-L1 by competing with SPOP for binding to PD-L1 in CRC cells. Regarding functionality, the absence of TMEM160 significantly inhibited the proliferation, invasion, metastasis, clonogenicity, and radioresistance of CRC cells, while simultaneously enhancing the cytotoxic effect of CD8 + T cells on tumor cells. Conversely, the upregulation of TMEM160 substantially increased these capabilities. In severely immunodeficient mice, tumor growth derived from lentiviral vector shTMEM160 cells was lower compared with that derived from shNC control cells. Furthermore, the downregulation of TMEM160 significantly restricted tumor growth in immune-competent BALB/c mice. In clinical samples from patients with CRC, we observed a strong positive correlation between TMEM160 expression and PD-L1 expression, as well as a negative correlation with CD8A expression. Importantly, patients with high TMEM160 expression exhibited a worse prognosis compared with those with low or no TMEM160 expression.

CONCLUSIONS

Our study reveals that TMEM160 inhibits the ubiquitination-dependent degradation of PD-L1 that is mediated by SPOP, thereby stabilizing PD-L1 expression to foster the malignant progress, radioresistance, and immune evasion of CRC cells. These findings suggest that TMEM160 holds potential as a target for the treatment of patients with CRC.

The effects of metabolism on the immune microenvironment in colorectal cancer

Colorectal cancer (CRC) is a malignancy that is widely prevalent worldwide. Due to its unsatisfactory treatment outcome and extremely poor prognosis, many studies on the molecular mechanisms and pathological mechanisms of CRC have been published in recent years. The tumor microenvironment (TME) is an extremely important feature of tumorigenesis and one of the hallmarks of tumor development. Metabolic reprogramming is currently a hot topic in tumor research, and studies on this topic have provided important insights into CRC development. In particular, metabolic reprogramming in cancer causes changes in the composition of energy and nutrients in the TME. Furthermore, it can alter the complex crosstalk between immune cells and associated immune factors, such as associated macrophages and T cells, which play important immune roles in the TME, in turn affecting the immune escape of tumors by altering immune surveillance. In this review, we summarize several metabolism-related processes affecting the immune microenvironment of CRC tumors. Our results showed that the immune microenvironment is regulated by metabolic reprogramming and influences the development of CRC.

Targeting the NF-κB pathway as a potential regulator of immune checkpoints in cancer immunotherapy

Advances in cancer immunotherapy over the last decade have led to the development of several agents that affect immune checkpoints. Inhibitory receptors expressed on T cells that negatively regulate the immune response include cytotoxic T‑lymphocyte antigen 4 (CTLA4) and programmed cell death protein 1 (PD1), which have been studied more than similar receptors. Inhibition of these proteins and other immune checkpoints can stimulate the immune system to attack cancer cells, and prevent the tumor from escaping the immune response. However, the administration of anti-PD1 and anti-CTLA4 antibodies has been associated with adverse inflammatory responses similar to autoimmune diseases. The current review discussed the role of the NF-κB pathway as a tumor promoter, and how it can govern inflammatory responses and affect various immune checkpoints. More precise knowledge about the communication between immune checkpoints and NF-κB pathways could increase the effectiveness of immunotherapy and reduce the adverse effects of checkpoint inhibitor therapy.

Targeting M2-like tumor-associated macrophages is a potential therapeutic approach to overcome antitumor drug resistance

Tumor drug resistance emerges from the interaction of two critical factors: tumor cellular heterogeneity and the immunosuppressive nature of the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) constitute essential components of the TME. M2-like TAMs are essential in facilitating tumor metastasis as well as augmenting the drug resistance of tumors. This review encapsulates the mechanisms that M2-like TAMs use to promote tumor drug resistance. We also describe the emerging therapeutic strategies that are currently targeting M2-like TAMs in combination with other antitumor drugs, with some still undergoing clinical trial evaluation. Furthermore, we summarize and analyze various existing approaches for developing novel drugs that target M2-like TAMs to overcome tumor resistance, highlighting how targeting M2-like TAMs can effectively stop tumor growth, metastasis, and overcome tumor drug resistance.

Role of the ubiquitin-proteasome system on macrophages in the tumor microenvironment

Tumor-associated macrophages (TAMs) are key components of the tumor microenvironment, and their different polarization states play multiple roles in tumors by secreting cytokines, chemokines, and so on, which are closely related to tumor development. In addition, the enrichment of TAMs is often associated with poor prognosis of tumors. Thus, targeting TAMs is a potential tumor treatment strategy, in which therapeutic approaches such as reducing TAMs numbers, remodeling TAMs phenotypes, and altering their functions are being extensively investigated. Meanwhile, the ubiquitin-proteasome system (UPS), an important mechanism of protein hydrolysis in eukaryotic cells, participates in cellular processes by regulating the activity and stability of key proteins. Interestingly, UPS plays a dual role in the process of tumor development, and its role in TAMs deserve to be investigated in depth. This review builds on this foundation to further explore the multiple roles of UPS on TAMs and identifies a promising approach to treat tumors by targeting TAMs with UPS.

Astragalus polysaccharide ameliorates CD8+ T cell dysfunction through STAT3/Gal-3/LAG3 pathway in inflammation-induced colorectal cancer

Chronic inflammation can promote cancer development as observed in inflammation-induced colorectal cancer (CRC). However, the poor treatment outcomes emphasize the need for effective treatment. Astragalus polysaccharide (APS), a vital component of the natural drug Astragalus, has anti-tumor effects by inhibiting cancer cell proliferation and enhancing immune function. In this study, we found that APS effectively suppressed CRC development through activating CD8+ T cells and reversing its inhibitory state in the tumor microenvironment (TME) of AOM/DSS inflammation-induced CRC mice. Network pharmacology and clinical databases suggested that the STAT3/ Galectin-3(Gal-3)/LAG3 pathway might be APS's potential target for treating CRC and associated with CD8+ T cell dysfunction. In vivo experiments showed that APS significantly reduced phosphorylated STAT3 and Gal-3 levels in tumor cells, as well as LAG3 in CD8+ T cells. Co-culture experiments with MC38 and CD8+ T cells demonstrated that APS decreased the expression of co-inhibitory receptor LAG3 in CD8+ T cells by targeting STAT3/Gal-3 in MC38 cells. Mechanism investigations revealed that APS specifically improved CD8+ T cell function through modulation of the STAT3/Gal-3/LAG3 pathway to inhibit CRC development, providing insights for future clinical development of natural anti-tumor drugs and immunotherapies as a novel strategy combined with immune checkpoint inhibitors (ICIs).

Single-cell RNA sequencing reveals that the immunosuppression landscape induced by chronic stress promotes colorectal cancer metastasis

The high prevalence of depressive disorders in individuals with cancer and their contribution to tumour progression is a topic that is gradually gaining attention. Recent evidence has shown that there are prominent connections between immune gene variants and mood disorders. The homeostasis of the tumour immune microenvironment (TIME) and the infiltration and activation of immune cells play a very important role in the antitumour effect. In this study, we established a compound mouse model with chronic unpredictable mild stress (CUMS) and orthotopic colorectal cancer to simulate colorectal cancer (CRC) patients with depression. Using 10✕Genomics single-cell transcriptome sequencing technology, we profiled nearly 30,000 cells from tumour samples of 8 mice from the control and CUMS groups, revealed that immune cells in tumours under a chronic stress state trend toward a more immunosuppressive and exhaustive status, and described the crosstalk between the overall inflammatory environment and immunosuppressive landscape to provide mechanistic information or efficacious strategies for immune-oncology treatments in CRC with depressive disorders.

Y-Box Binding Protein 1: Unraveling the Multifaceted Role in Cancer Development and Therapeutic Potential

Y-box binding protein 1 (YBX1), a member of the Cold Shock Domain protein family, is overexpressed in various human cancers and is recognized as an oncogenic gene associated with poor prognosis. YBX1's functional diversity arises from its capacity to interact with a broad range of DNA and RNA molecules, implicating its involvement in diverse cellular processes. Independent investigations have unveiled specific facets of YBX1's contribution to cancer development. This comprehensive review elucidates YBX1's multifaceted role in cancer across cancer hallmarks, both in cancer cell itself and the tumor microenvironment. Based on this, we proposed YBX1 as a potential target for cancer treatment. Notably, ongoing clinical trials addressing YBX1 as a target in breast cancer and lung cancer have showcased its promise for cancer therapy. The ramp up in in vitro research on targeting YBX1 compounds also underscores its growing appeal. Moreover, the emerging role of YBX1 as a neural input is also proposed where the high level of YBX1 was strongly associated with nerve cancer and neurodegenerative diseases. This review also summarized the up-to-date advanced research on the involvement of YBX1 in pancreatic cancer.

Exosomes secreted by ST3GAL5high cancer cells promote peritoneal dissemination by establishing a premetastatic microenvironment

Peritoneal dissemination of cancer affects patient survival. The behavior of peritoneal mesothelial cells (PMCs) and immune cells influences the establishment of a microenvironment that promotes cancer cell metastasis in the peritoneum. Here, we investigated the roles of lactosylceramide alpha-2,3-sialyltransferase (ST3G5; also known as ST3GAL5 and GM3 synthase) in the exosome-mediated premetastatic niche in peritoneal milky spots (MSs). Exosomes secreted from ST3G5high cancer cells (ST3G5high -cExos) were found to contain high levels of hypoxia-inducible factor 1-alpha (HIF1α) and accumulated in MSs via uptake in macrophages (MΦs) owing to increased expression of sialic acid-binding Ig-like lectin 1 (CD169; also known as SIGLEC1). ST3G5high -cExos induced pro-inflammatory cytokines and glucose metabolic changes in MΦs, and the interaction of these MΦs with PMCs promoted mesothelial-mesenchymal transition (MMT) in PMCs, thereby generating αSMA+ myofibroblasts. ST3G5high -cExos also increased the expression of immune checkpoint molecules and T-cell exhaustion in MSs, which accelerated metastasis to the omentum. These events were prevented following ST3G5 depletion in cancer cells. Mechanistically, ST3G5high -cExos upregulated chemokines, including CC-chemokine ligand 5 (CCL5), in recipient MΦs and dendritic cells (DCs), which induced MMT and immunosuppression via activation of signal transducer and activator of transcription 3 (STAT3). Maraviroc, a C-C chemokine receptor type 5 (CCR5) antagonist, prevented ST3G5high -cExo-mediated MMT, T-cell suppression, and metastasis in MSs. Our results suggest ST3G5 as a suitable therapeutic target for preventing cExo-mediated peritoneal dissemination.

Curcumin inhibits colon cancer malignant progression and promotes T cell killing by regulating miR-206 expression

Colon cancer is a great threat to human health. Curcumin, as a traditional Chinese medicine extract with anti-tumor and anti-inflammatory effects, can affect the development of diverse human diseases including cancer. The aim of this research was to probe the mechanism by which curcumin regulates colon cancer progression. Colon cancer cells were processed with graded concentrations of curcumin. The proliferation and apoptosis of the treated cells were determined by MTT, colony formation assay and flow cytometry. Expression of signaling pathway-related proteins and programmed death-ligand 1 (PD-L1) was measured by western blotting. The effect of curcumin on tumor cell growth was verified through T cell-mediated killing and ELISA assays. The relationship between target gene expression and the survival rate of colon cancer patients was analyzed by a survival curve. Curcumin treatment restrained proliferation and accelerated apoptosis of colon cancer cells. It elevated miR-206 expression, which in turn affected colon cancer cell function. miR-206 enhanced colon cancer cell apoptosis and inhibited PD-L1 expression; thus, curcumin enhanced the killing effect of T cells on tumor cells by suppressing PD-L1 through inhibiting the JAK/STAT3 pathway. Patients with high expression of miR-206 had better survival rates than those with low expression. Curcumin can regulate miR-206 expression and inhibit the malignant behavior of colon cancer cells and enhance T cell killing through the JAK/STAT3 pathway.

The functional roles of chemokines and chemokine receptors in colorectal cancer progression

Colorectal cancer is a common malignancy with significant rates of morbidity and mortality. A number of factors, including the tumor microenvironment, chemokines, the inflammatory response, have an impact on the development of colorectal cancer. A critical component of the tumor microenvironment is chemokines. Various cell subsets are attracted to the tumor microenvironment through interactions with chemokine receptors. These cells have varying effects on the development of the tumor and the effectiveness of treatment. Additionally, chemokines can participate in inflammatory processes and have effects that are either pro- or anti-tumor. Chemokines can be exploited as targets for medication resistance and treatment in colorectal cancer. In this review, we discuss the expression of chemokines and chemokine receptors, and their relationship with immune cells in the tumor microenvironment. At the same time, we also collect and discuss the significance of chemokines and chemokine receptors in colorectal cancer progression, and their potential as molecular targets for CRC treatment.

HSF1 is involved in immunotherapeutic response through regulating APOJ/STAT3-mediated PD-L1 expression in hepatocellular carcinoma

Hepatocellular cancer (HCC) is a serious illness with high prevalence and mortality throughout the whole world. For advanced HCC, immunotherapy is somewhat impactful and encouraging. Nevertheless, a substantial proportion of patients with advanced HCC are still unable to achieve a durable response, owing to heterogeneity from clonal variability and differential expression of the PD-1/PD-L1 axis. Recently, heat shock factor 1 (HSF1) is recognized as an important component of tumor immunotherapeutic response as well as related to PD-L1 expression in cancer. However, the mechanism of HSF1 regulating PD-L1 in cancer, especially in HCC, is still not fully clear. In this study, we observed the significantly positive correlation between HSF1 expression and PD-L1 expression in HCC samples; meanwhile combination expressions of HSF1 and PD-L1 served as the signature for predicting prognosis of patients with HCC. Mechanistically, HSF1 upregulated PD-L1 expression by inducing APOJ expression and activating STAT3 signaling pathway in HCC. In addition, we explored further the potential values of targeting the HSF1-APOJ-STAT3 axis against CD8+ T cells-mediated cancer cells cytotoxicity. These findings unveiled the important involvement of HSF1 in regulating PD-L1 expression in HCC as well as provided a novel invention component for improving the clinical response rate and efficacy of PD-1/PD-L1 blockade.

PABPN1 functions as a predictive biomarker in colorectal carcinoma

PURPOSE

PABPN1 acts as a modulator of poly(A) tail length and alternative polyadenylation. This research was aimed to explore the role of PABPN1 in colorectal cancer (CRC).

METHODS

Public databases were performed to analyze expression, location, roles of prognosis and tumor immunity and interaction with RNAs and proteins of PABPN1. To investigate PABPN1 expression in tissues, 78 CRC specimens were collected to conduct IHC, and 30 pairs of frozen CRC and corresponding adjacent normal tissues were used to conduct qRT-PCR and WB. In addition, in vitro experiments were then carried out to identify the role of PABPN1 in CRC.

RESULTS

Compared with normal tissues, PABPN1 expression was significant higher in CRC. Its high level predicted poor outcome of CRC. Th1 and Treg had significant negative relationships not only with PABPN1 expression, but also with six molecules interacting with PABPN1, including IFT172, KIAA0895L, RECQL4, WDR6, PABPC1 and NCBP1. In addition, PABPN1 had negative relationships with quite a few immune markers, such as CSF1R, IL-10, CCL2 and so on. In cellular experiments, silencing PABPN1 inhibited proliferation and promoted apoptosis in HCT-116 CRC cells.

CONCLUSION

In summary, PABPN1 might become a novel biomarker and correlate with tumor immunity in CRC.

Common clinicopathological and immunological features of sarcomatoid carcinoma across organs: A histomorphology-based cross-organ study

Sarcomatoid carcinoma (SC), which can occur in any organ, is a rare disease. To elucidate common characteristics of SC beyond organs, we evaluated clinicopathological and immunological features of SC defined by the single histological criterion beyond organs compared to randomly matched conventional carcinoma (non-SC) adjusted for the disease stage. Immunological features were assessed by multiplex immunohistochemistry, comparing immune cell density in tumor tissues and tumor programmed death-ligand 1 (PD-L1) expression. A total of 101 patients with SC or non-SC (31 lung, 19 esophagus, 22 pancreas, 15 liver, 4 bile duct, 6 kidney, 2 uterus and 2 ovary) were identified among 7197 patients who underwent surgery at our institute (1997-2020). SC was significantly associated with worse survival (HR: 1.571; 95% CI: 1.084-2.277; P = .017). The frequency of postoperative progression within 6 months was significantly higher for SC patients (54% vs 28%; P = .002). The immune profiling revealed the densities of CD8+ T cells (130 vs 72 cells/mm2 ; P = .004) and tumor-associated macrophages (566 vs 413 cells/mm2 ; P < .0001) and the tumor PD-L1 expression score (40% vs 5%; P < .0001) were significantly higher in SCs than in non-SCs. Among 73 SC patients with postoperative progression, multivariate Cox regression analysis showed that immunotherapy tended to be associated with favorable survival (HR: 0.256; 95% CI: 0.062-1.057; P = .060). Collectively, SCs shared clinicopathological and immunological features across organs. Our study can initiate to standardize the pathological definition of SC and provide a rationale for the investigation and development for this rare disease in a cross-organ manner.

Gut microbiome: decision-makers in the microenvironment of colorectal cancer

Colorectal cancer (CRC) is a common malignancy of the gastrointestinal tract, accounting for the second most common cause of gastrointestinal tumors. As one of the intestinal barriers, gut bacteria form biofilm, participate in intestinal work, and form the living environment of intestinal cells. Metagenomic next-generation sequencing (mNGS) of the gut bacteria in a large number of CRC patients has been established, enabling specific microbial signatures to be associated with colorectal adenomato-carcinoma. Gut bacteria are involved in both benign precursor lesions (polyps), in situ growth and metastasis of CRC. Therefore, the term tumorigenic bacteria was proposed in 2018, such as Escherichia coli, Fusobacterium nucleatum, enterotoxigenic Bacteroides fragilis, etc. Meanwhile, bacteria toxins (such as cytolethal distending toxin (CDT), Colibactin (Clb), B. fragilis toxin) affect the tumor microenvironment and promote cancer occurrence and tumor immune escape. It is important to note that there are differences in the bacteria of different types of CRC. In this paper, the role of tumorigenic bacteria in the polyp-cancer transformation and the effects of their secreted toxins on the tumor microenvironment will be discussed, thereby further exploring new ideas for the prevention and treatment of CRC.

Chemokine- and chemokine receptor-based signature predicts immunotherapy response in female colorectal adenocarcinoma patients

The clinical significance and comprehensive characteristics of chemokines and chemokine receptors in female patients with advanced colorectal adenocarcinoma have not ever been reported. Our study explored the expression profiles of chemokines and chemokine receptors and constructed a chemokine- and chemokine receptor-based signature in female patients with advanced colorectal adenocarcinoma. Four independent cohorts containing 1335 patients were enrolled in our study. Univariate Cox regression and least absolute shrinkage and selection operator (LASSO) analyses were performed to construct the signature. CIBERSORT was used to evaluate the landscape of immune cell infiltration. Thirty-two pairs of tissue specimens of female advanced colorectal cancer (CRC) patients and two CRC cell lines were used to validate the signature in vitro. Quantitative real-time PCR and western blotting were performed to validate the mRNA and protein expression levels of signature genes. EdU and colony formation assays were performed to examine proliferative ability. Transwell and wound healing assays were used to evaluate cell invasion and migration capacity. During the signature construction and validation process, we found that the signature was more applicable to female patients with advanced colorectal adenocarcinoma. Hence, the subsequent study mainly focused on the particular subgroup. Enrichment analyses revealed that the signature was closely related to immunity. The landscape of immune cell infiltration presented that the signature was significantly associated with T cells CD8 and neutrophils. Gene set enrichment analysis (GSEA) confirmed that the high-risk group was chiefly enriched in the tumor-promoting related pathways and biological processes, whereas the low-risk group was mainly enriched in anti-tumor immune response pathways and biological processes. The signature was closely correlated with CTLA4, PDL1, PDL2, TMB, MSI, and TIDE, indicating that our signature could serve as a robust biomarker for immunotherapy and chemotherapy response. ROC curves verified that our signature had more robust prognostic power than all immune checkpoints and immunotherapy-related biomarkers. Finally, we used 32 pairs of tissue specimens and 2 CRC cell lines to validate our signature in vitro. We first provided a robust prognostic chemokine- and chemokine receptor-based signature, which could serve as a novel biomarker for immunotherapy and chemotherapy response to guide individualized treatment for female patients with advanced colorectal adenocarcinoma.

Immune-related gene-based model predicts the survival of colorectal carcinoma and reflected various biological statuses

Bakcground: Prognosis of colorectal cancer (CRC) varies due to complex genetic-microenviromental interactions, and multiple gene-based prognostic models have been highlighted. Material and Method: In this work, the immune-related genes' expression-based model was developed and the scores of each sample were calculated. The correlation between the model and clinical information, immune infiltration, drug response and biological pathways were analyzed. Results: The high-score samples have a significantly longer survival (overall survival and progression-free survival) period than those with a low score, which was validated across seven datasets containing 1,325 samples (GSE17536 (N = 115), GSE17537 (N = 55), GSE33113 (N = 90), GSE37892 (N = 130), GSE38832 (N = 74), GSE39582 (N = 481), and TCGA (N = 380)). The score is significantly associated with clinical indicators, including age and stage, and further associated with PD-1/PD-L1 gene expression. Furthermore, high-score samples have significantly higher APC and a lower MUC5B mutation rate. The high-score samples show more immune infiltration (including CD4+ and CD8+ T cells, M1/M2 macrophages, and NK cells). Enriched pathway analyses showed that cancer-related pathways, including immune-related pathways, were significantly activated in high-score samples and that some drugs have significantly lower IC50 values than those with low score. Conclusion: The model developed based on immune-related genes is robust and reflected various statuses of CRC and may be a potential clinical indicator.

Hepatocellular Carcinoma Subtyping and Prognostic Model Construction Based on Chemokine-Related Genes

BACKGROUND

Chemokines not only regulate immune cells but also play significant roles in development and treatment of tumors and patient prognoses. However, these effects have not been fully explained in hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

We conducted a clustering analysis of chemokine-related genes. We then examined the differences in survival rates and analyzed immune levels using single-sample Gene Set Enrichment Analysis (ssGSEA) for each subtype. Based on chemokine-related genes of different subtypes, we built a prognostic model in The Cancer Genome Atlas (TCGA) dataset using the survival package and glmnet package and validated it in the Gene Expression Omnibus (GEO) dataset. We used univariate and multivariate regression analyses to select independent prognostic factors and used R package rms to draw a nomogram reflecting patient survival rates at 1, 3, and 5 years.

RESULTS

We identified two chemokine subtypes and, after screening, found that Cluster1 had higher survival rates than Cluster2. In addition, in terms of immune evaluation, stromal evaluation, ESTIMATE evaluation, immune abundance, immune function, and expressions of various immune checkpoints, immune levels of Cluster1 were significantly better than those of Cluster2. The immunophenoscore (IPS) of HCC patients in Cluster1 was significantly higher than that in Cluster2. Furthermore, we established a prognostic model consisting of 9 genes, which correlated with chemokines. Through testing, Riskscore was revealed as an independent prognostic factor, and the model could effectively predict HCC patients' prognoses in both TCGA and GEO datasets.

CONCLUSION

This study resulted in the development of a novel prognostic model related to chemokine genes, providing new targets and theoretical support for HCC patients.

Alveolar macrophages in lung cancer: opportunities challenges

Alveolar macrophages (AMs) are critical components of the innate defense mechanism in the lung. Nestled tightly within the alveoli, AMs, derived from the yolk-sac or bone marrow, can phagocytose foreign particles, defend the host against pathogens, recycle surfactant, and promptly respond to inhaled noxious stimuli. The behavior of AMs is tightly dependent on the environmental cues whereby infection, chronic inflammation, and associated metabolic changes can repolarize their effector functions in the lungs. Several factors within the tumor microenvironment can re-educate AMs, resulting in tumor growth, and reducing immune checkpoint inhibitors (ICIs) efficacy in patients treated for non-small cell lung cancer (NSCLC). The plasticity of AMs and their critical function in altering tumor responses to ICIs make them a desirable target in lung cancer treatment. New strategies have been developed to target AMs in solid tumors reprograming their suppressive function and boosting the efficacy of ICIs. Here, we review the phenotypic and functional changes in AMs in response to sterile inflammation and in NSCLC that could be critical in tumor growth and metastasis. Opportunities in altering AMs' function include harnessing their potential function in trained immunity, a concept borrowed from memory response to infections, which could be explored therapeutically in managing lung cancer treatment.

STAT3 as a newly emerging target in colorectal cancer therapy: Tumorigenesis, therapy response, and pharmacological/nanoplatform strategies

Colorectal cancer (CRC) ranks as the third most aggressive tumor globally, and it can be categorized into two forms: colitis-mediated CRC and sporadic CRC. The therapeutic approaches for CRC encompass surgical intervention, chemotherapy, and radiotherapy. However, even with the implementation of these techniques, the 5-year survival rate for metastatic CRC remains at a mere 12-14%. In the realm of CRC treatment, gene therapy has emerged as a novel therapeutic approach. Among the crucial molecular pathways that govern tumorigenesis, STAT3 plays a significant role. This pathway is subject to regulation by cytokines and growth factors. Once translocated into the nucleus, STAT3 influences the expression levels of factors associated with cell proliferation and metastasis. Literature suggests that the upregulation of STAT3 expression is observed as CRC cells progress towards metastatic stages. Consequently, elevated STAT3 levels serve as a significant determinant of poor prognosis and can be utilized as a diagnostic factor for cancer patients. The biological and malignant characteristics of CRC cells contribute to low survival rates in patients, as the upregulation of STAT3 prevents apoptosis and promotes pro-survival autophagy, thereby accelerating tumorigenesis. Furthermore, STAT3 plays a role in facilitating the proliferation of CRC cells through the stimulation of glycolysis and promoting metastasis via the induction of epithelial-mesenchymal transition (EMT). Notably, an intriguing observation is that the upregulation of STAT3 can mediate resistance to 5-fluorouracil, oxaliplatin, and other anti-cancer drugs. Moreover, the radio-sensitivity of CRC diminishes with increased STAT3 expression. Compounds such as curcumin, epigallocatechin gallate, and other anti-tumor agents exhibit the ability to suppress STAT3 and its associated pathways, thereby impeding tumorigenesis in CRC. Furthermore, it is worth noting that nanostructures have demonstrated anti-proliferative and anti-metastatic properties in CRC.

Manganese-Implanted Titanium Modulates the Crosstalk between Bone Marrow Mesenchymal Stem Cells and Macrophages to Improve Osteogenesis

Manganese (Mn) is an essential micronutrient in various physiological processes, but its functions in bone metabolism remain undefined. This is partly due to the interplay between immune and bone cells because Mn plays a central role in the immune system. In this study, we utilized the plasma immersion ion implantation and deposition (PIII&D) technique to introduce Mn onto the titanium surface. The results demonstrated that Mn-implanted surfaces stimulated the shift of macrophages toward the M1 phenotype and had minimal effects on the osteogenic differentiation of mouse bone marrow mesenchymal stem cells (mBMSCs) under mono-culture conditions. However, they promoted the M2 polarization of macrophages and improved the osteogenic activities of mBMSCs under co-culture conditions, indicating the importance of the crosstalk between mBMSCs and macrophages mediated by Mn in osteogenic activities. This study provides a positive incentive for the application of Mn in the field of osteoimmunology.

Siglec-9+ tumor-associated macrophages delineate an immunosuppressive subset with therapeutic vulnerability in patients with high-grade serous ovarian cancer

BACKGROUND

The potent immunosuppressive properties of sialic acid-binding immunoglobulin-like lectin-9 (Siglec-9) on myeloid cells and lymphocytes provide a strong rationale for serving as a therapeutic target. However, the expression profile and critical role of Siglec-9 in high-grade serous ovarian cancer (HGSC) remain obscure. This study aimed to elucidate the prognostic significance of Siglec-9 expression and its predictive value for immunotherapy in HGSC.

METHODS

Study enrolled two cohorts, consisting of 120 tumor microarray specimens of HGSC for immunohistochemistry (IHC) and 40 fresh tumor specimens for flow cytometry (FCM). Expression profile of Siglec-9 in immune cells was analyzed by both bioinformatics analysis and FCM. Role of Siglec-9 was studied to identify that Siglec-9+TAMs linked with an immunosuppressive phenotype by IHC and FCM, and block Siglec-9 was sensitive to immunotherapy by ex vivo and in vitro assays.

RESULTS

Siglec-9 is predominantly expressed on tumor-associated macrophages (TAMs). High Siglec-9+TAMs were associated with inferior overall survival (OS). Both tumor-conditioned medium (TCM) and tumor ascites induced enrichment of Siglec-9+TAMs with protumorigenic phenotypes. Siglec-9+TAMs were associated with immunosuppressive tumor microenvironment (TME) characterized by exhausted CD8+T cells and increased immune checkpoint expression. Blockade of Siglec-9 suppressed phosphorylation of the inhibitory phosphatase SHP-1 and repolarized TAMs to antitumorigenic phenotype and retrieved cytotoxic activity of CD8+T cells in vitro and ex vivo. Responders toward antiprogrammed death receptor-1 (anti-PD-1) therapy present more Siglec-9+TAMs than non-responders. Furthermore, blockade Siglec-9 synergized with anti-PD-1 antibody to enhance the cytotoxic activity of CD8+T cells in tissues with higher Siglec-9+TAMs.

CONCLUSIONS

Siglec-9+TAMs may serve as an independent prognostic of poor survival but a predictive biomarker for anti-PD-1/antiprogrammed death ligand-1 immunotherapy in HGSC. In addition, the potential of immunosuppressive Siglec-9+TAMs as a therapeutic target is worth further exploration.

Regulation of post-translational modification of PD-L1 and advances in tumor immunotherapy

The immune checkpoint molecules programmed cell death receptor 1 (PD-1) and programmed death ligand 1 (PD-L1) are one of the most promising targets for tumor immunotherapy. PD-L1 is overexpressed on the surface of tumor cells and inhibits T cell activation upon binding to PD⁃1 on the surface of T cells, resulting in tumor immune escape. The therapeutic strategy of targeting PD-1/PD-L1 involves blocking this binding and restoring the tumor-killing effect of immune cells. However, in clinical settings, a relatively low proportion of cancer patients have responded well to PD-1/PD-L1 blockade, and clinical outcomes have reached a bottleneck and no substantial progress has been made. In recent years, PD-L1 post-translation modifications (PTMs) have gradually become a hot topic in the field of PD-L1 research, which will provide new insights to improve the efficacy of current anti-PD-1/PD-L1 therapies. Here, we summarized and discussed multiple PTMs of PD-L1, including glycosylation, ubiquitination, phosphorylation, acetylation and palmitoylation, with a major emphasis on mechanism-based therapeutic strategies (including relevant enzymes and targets that are already in clinical use and that may become drugs in the future). We also summarized the latest research progress of PTMs of PD-L1/PD-1 in regulating immunotherapy. The review provided novel strategies and directions for tumor immunotherapy research based on the PTMs of PD-L1/PD-1.

Potential therapeutic targets of macrophages in inhibiting immune damage and fibrotic processes in musculoskeletal diseases

Macrophages are a heterogeneous cell type with high plasticity, exhibiting unique activation characteristics that modulate the progression and resolution of diseases, serving as a key mediator in maintaining tissue homeostasis. Macrophages display a variety of activation states in response to stimuli in the local environment, with their subpopulations and biological functions being dependent on the local microenvironment. Resident tissue macrophages exhibit distinct transcriptional profiles and functions, all of which are essential for maintaining internal homeostasis. Dysfunctional macrophage subpopulations, or an imbalance in the M1/M2 subpopulation ratio, contribute to the pathogenesis of diseases. In skeletal muscle disorders, immune and inflammatory damage, as well as fibrosis induced by macrophages, are prominent pathological features. Therefore, targeting macrophages is of great significance for maintaining tissue homeostasis and treating skeletal muscle disorders. In this review, we discuss the receptor-ligand interactions regulating macrophages and identify potential targets for inhibiting collateral damage and fibrosis in skeletal muscle disorders. Furthermore, we explore strategies for modulating macrophages to maintain tissue homeostasis.

Targeting the Siglec-sialic acid axis promotes antitumor immune responses in preclinical models of glioblastoma

Glioblastoma (GBM) is the most aggressive form of primary brain tumor, for which effective therapies are urgently needed. Cancer cells are capable of evading clearance by phagocytes such as microglia- and monocyte-derived cells through engaging tolerogenic programs. Here, we found that high expression of sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9) correlates with reduced survival in patients with GBM. Using microglia- and monocyte-derived cell-specific knockouts of Siglec-E, the murine functional homolog of Siglec-9, together with single-cell RNA sequencing, we demonstrated that Siglec-E inhibits phagocytosis by these cells, thereby promoting immune evasion. Loss of Siglec-E on monocyte-derived cells further enhanced antigen cross-presentation and production of pro-inflammatory cytokines, which resulted in more efficient T cell priming. This bridging of innate and adaptive responses delayed tumor growth and resulted in prolonged survival in murine models of GBM. Furthermore, we showed the combinatorial activity of Siglec-E blockade and other immunotherapies demonstrating the potential for targeting Siglec-9 as a treatment for patients with GBM.

Lysine N-methyltransferase SETD7 promotes bladder cancer progression and immune escape via STAT3/PD-L1 cascade

Background: The immunotherapy sensitivity of patients with bladder cancer (BCa) remains low. As the role of protein methylation in tumorigenesis and development becomes clearer, the role of lysine N-methyltransferase SET domain containing 7 (SETD7) in the progression and immune escape of BCa is worth studying. Methods: The correlation between lysine methyltransferase family and prognosis or immunotheray sensitivity of BCa patients were analyzed, and SETD7 was screened out because of the significant correlation between its expression and survival data or immunotherapy sensitivity. The expression of SETD7 in BCa tissues and cell lines were explored. The functions of SETD7 were investigated by proliferation and migration assays. The role of SETD7 in BCa immune escape was validated by analyzing the correlation between SETD7 expression and tumor microenvironment (TME)-related indicators. The results were further confirmed by conducting BCa cell-CD8+ T cell co-culture assays and tumorigenesis experiment in human immune reconstitution NOG mice (HuNOG mice). Bioinformatic prediction, CO-IP, qRT-PCR, and western blot were used to validate the SETD7/STAT3/PD-L1 cascade. Results: SETD7 was highly expressed in BCa, and it was positively associated with high histological grade and worse prognosis. SETD7 promoted the proliferation and migration of BCa cells. The results of bioinformatics, in vitro co-culture, and in vivo tumorigenesis assays showed that SETD7 could inhibit the chemotoxis and cytotoxicity of CD8+ T cells in BCa TME. Mechanistically, bioinformatics analysis, CO-IP assay, qRT-PCR, and western blot results indicated that SETD7 could increase the expression of PD-L1 via binding and promoting STAT3. Conclusions: Taken together, SETD7 indicated poor prognosis and promoted the progression and immune escape of BCa cells. It has great potential to act as a new indicator for BCa diagnosis and treatment, especially immunotherapy.

Emerging role of deubiquitination modifications of programmed death-ligand 1 in cancer immunotherapy

Immune evasion is essential for carcinogenesis and cancer progression. Programmed death-ligand 1 (PD-L1), a critical immune checkpoint molecule, interacts with programmed death receptor-1 (PD-1) on immune cells to suppress anti-tumor immune responses. In the past decade, antibodies targeting PD-1/PD-L1 have tremendously altered cancer treatment paradigms. Post-translational modifications have been reported as key regulators of PD-L1 expression. Among these modifications, ubiquitination and deubiquitination are reversible processes that dynamically control protein degradation and stabilization. Deubiquitinating enzymes (DUBs) are responsible for deubiquitination and have emerged as crucial players in tumor growth, progression, and immune evasion. Recently, studies have highlighted the participation of DUBs in deubiquitinating PD-L1 and modulating its expression. Here, we review the recent developments in deubiquitination modifications of PD-L1 and focus on the underlying mechanisms and effects on anti-tumor immunity.

Salvia mitiorrhiza Bunge aqueous extract attenuates infiltration of tumor-associated macrophages and potentiates anti-PD-L1 immunotherapy in colorectal cancer through modulating Cox2/PGE2 cascade

ETHNOPHARMACOLOGICAL RELEVANCE

Based on the notion of traditional Chinese medicine, the theory of invigorating the circulation of blood is a prominent treatment for cancer in clinic. Therefore, Salvia miltiorrhiza Bunge, as a representative of Chinese medicine of invigorating the circulation of blood, has been proved to be an effective medicinal herb for treating cancer.

AIM OF THE STUDY

To clarify the anti-cancer effect of Salvia miltiorrhiza Bunge aqueous extract (SMAE) on colorectal cancer (CRC) and investigate whether the therapeutic effect of SMAE was mediated by attenuating the infiltration of tumor-associated macrophages (TAMs) into the tumor microenvironment (TME).

MATERIALS AND METHODS

High-performance liquid chromatography (HPLC) was used for determined the main compounds of SMAE. MC38 cells were subcutaneously injected into the mice to establish the mouse model of CRC. Tumor growth curve was detected by tumor volume measurement. The model group received distilled water irrigation once a day. SMAE-treated group received 5 g/kg or 10 g/kg SMAE once a day. Anti-PD-L1 treated group received 5 mg/kg anti-PD-L1 once every three days. Protein expression of Cox2 and PD-L1 was determined by western blot assay. The secretion levels of PGE2, IL-1β, IL-6, MCP-1, and GM-CSF were evaluated through ELISA. The mRNA expression of CSF1, CCL2, CXCL1, CXCL2, and CXCL3 was measured by using RT-qPCR. Staining of Ki67, TUNEL and Caspase3 was used to investigate cell proliferation and apoptosis. Immunohistochemical staining was used to determine CD8⁺ T cell distribution. H&E staining was used to confirm histopathological changes. The expressions of F4/80 and CD68 were measured by flow cytometry to identify macrophages in tumors and lymph nodes. The number of CD8⁺ T cells and the expression of PD-1, IFN-γ, and Granzyme B (GZMB) were determined by flow cytometry.

RESULTS

SMAE significantly retarded the growth of MC38 mouse colorectal cancer. SMAE strikingly inhibited the expression of Cox2 and impaired the secretion of PGE2 in tumors, contributing to the attenuated intra-tumoral infiltration of TAMs via Cox2/PGE2 cascade. Meanwhile, SMAE augmented anti-tumor immunity by the elevated proportion of IFN-γ⁺ CD8⁺ T cells and GZMB⁺ CD8⁺ T cells, which decreased the tumor load. Furthermore, the combination of SMAE and anti-PD-L1 showed a higher therapeutic efficacy than either monotherapy in controlling tumor growth in MC38 xenograft model.

CONCLUSIONS

SMAE attenuated the infiltration of TAMs into tumors and synergized with anti-PD-L1 to treat CRC via modulating Cox2/PGE2 cascade.

Tumor-Associated Macrophage-Derived Exosomal LINC01232 Induces the Immune Escape in Glioma by Decreasing Surface MHC-I Expression

Tumor-associated macrophage (TAM) infiltration facilitates glioma malignancy, but the underlying mechanisms remain unclear. Herein, it is reported that TAMs secrete exosomal LINC01232 to induce tumor immune escape. Mechanistically, LINC01232 is found to directly bind E2F2 and promote E2F2 entry into the nucleus; the two synergistically promots the transcription of NBR1. The increase in binding between NBR1 binding and the ubiquitinating MHC-I protein through the ubiquitin domain causes an increase in the degradation of MHC-I in autophagolysosomes and a decrease in the expression of MHC-I on the surface of tumor cells, which in turn led to tumor cell escape from CD8⁺ CTL immune attack. Disruption of E2F2/NBR1/MHC-I signaling with shRNAs or blockade with the corresponding antibodies largely abolishes the tumor-supportive effects of LINC01232 and inhibits tumor growth driven by M2-type macrophages. Importantly, knockdown of LINC01232 enhances the expression of MHC-I on the surface of tumor cells and improves the response to reinfusion with CD8⁺ T cells. This study reveals the existence of critical molecular crosstalk between TAMs and glioma mediates through the LINC01232/E2F2/NBR1/MHC-I axis to support malignant tumor growth, indicating that targeting this axis may have therapeutic potential.