Pancreatic melatonin enhances anti-tumor immunity in pancreatic adenocarcinoma through regulating tumor-associated neutrophils infiltration and NETosis

Neutrophils as promising therapeutic targets in pancreatic cancer liver metastasis

Pancreatic cancer is characterized by an extremely poor prognosis and presents significant treatment challenges. Liver metastasis is the leading cause of death in patients with pancreatic cancer. Recent studies have highlighted the significant impact of neutrophils on tumor occurrence and progression, as well as their crucial role in the pancreatic cancer tumor microenvironment. Neutrophil infiltration plays a critical role in the progression and prognosis of pancreatic cancer. Neutrophils contribute to pancreatic cancer liver metastasis through various mechanisms, including angiogenesis, immune suppression, immune evasion, and epithelial-mesenchymal transition (EMT). Therefore, targeting neutrophils holds promise as an important therapeutic strategy for inhibiting pancreatic cancer liver metastasis. This article provides a summary of research findings on the involvement of neutrophils in pancreatic cancer liver metastasis and analyzes their potential as therapeutic targets. This research may provide new insights for the treatment of pancreatic cancer and improve the prognosis of patients with this disease.

Drug resistance and tumor immune microenvironment: An overview of current understandings (Review)

The use of antitumor drugs represents a reliable strategy for cancer therapy. Unfortunately, drug resistance has become increasingly common and contributes to tumor metastasis and local recurrence. The tumor immune microenvironment (TME) consists of immune cells, cytokines and immunomodulators, and collectively they influence the response to treatment. Epigenetic changes including DNA methylation and histone modification, as well as increased drug exportation have been reported to contribute to the development of drug resistance in cancers. In the past few years, the majority of studies on tumors have only focused on the development and progression of a tumor from a mechanistic standpoint; few studies have examined whether the changes in the TME can also affect tumor growth and drug resistance. Recently, emerging evidence have raised more concerns regarding the role of TME in the development of drug resistance. In the present review, it was discussed how the suppressive TME adapts to drug resistance characterized by the cooperation of immune cells, cytokines, immunomodulators, stromal cells and extracellular matrix. Furthermore, it was reviewed how these immunological or metabolic changes alter immuno‑surveillance and thus facilitate tumor drug resistance. In addition, potential targets present in the TME for developing novel therapeutic strategies to improve individualized therapy for cancer treatment were revealed.

In Vitro and In Vivo Effects of Melatonin-Containing Combinations in Human Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has poor prognosis and high mortality rates. Therefore, it is necessary to identify new targets and therapeutic strategies to improve the prognosis of patients with PDAC. Integrative therapies are increasingly being used to boost the efficacy of the known anticancer therapeutic approaches. Hence, this study aimed to evaluate the effects of a novel combination of different potential anticancer molecules, melatonin (MLT), cannabidiol (CBD), and oxygen-ozone (O2/O3) to treat PDAC using in vitro and in vivo models of human PDAC. The effect of this combination was investigated in combination with gemcitabine (GEM), the most common chemotherapeutic drug used for PDAC treatment. The combination of MLT + CBD + O2/O3 was more effective than the individual treatments in inhibiting PDAC cell viability and proliferation, inducing cell death, and modulating the RAS pathway protein levels. Moreover, different combinations of treatments reduced tumor mass in the PDAC mouse model, thus promoting the effect of GEM. In conclusion, a mixture of MLT + CBD + O2/O3 could serve as a potential adjuvant therapeutic strategy for PDAC.

Targeting NETosis: nature's alarm system in cancer progression

Neutrophils are recognized active participants in inflammatory responses and are intricately linked to cancer progression. In response to inflammatory stimuli, neutrophils become activated, releasing neutrophils extracellular traps (NETs) for the capture and eradication of pathogens, a phenomenon termed NETosis. With a deeper understanding of NETs, there is growing evidence supporting their role in cancer progression and their involvement in conferring resistance to various cancer therapies, especially concerning tumor reactions to chemotherapy, radiation therapy (RT), and immunotherapy. This review summarizes the roles of NETs in the tumor microenvironment (TME) and their mechanisms of neutrophil involvement in the host defense. Additionally, it elucidates the mechanisms through which NETs promote tumor progression and their role in cancer treatment resistance, highlighting their potential as promising therapeutic targets in cancer treatment and their clinical applicability.

Unbiasedly decoding the tumor microenvironment with single-cell multiomics analysis in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a poor prognosis and limited therapeutic options. Research on the tumor microenvironment (TME) of PDAC has propelled the development of immunotherapeutic and targeted therapeutic strategies with a promising future. The emergence of single-cell sequencing and mass spectrometry technologies, coupled with spatial omics, has collectively revealed the heterogeneity of the TME from a multiomics perspective, outlined the development trajectories of cell lineages, and revealed important functions of previously underrated myeloid cells and tumor stroma cells. Concurrently, these findings necessitated more refined annotations of biological functions at the cell cluster or single-cell level. Precise identification of all cell clusters is urgently needed to determine whether they have been investigated adequately and to identify target cell clusters with antitumor potential, design compatible treatment strategies, and determine treatment resistance. Here, we summarize recent research on the PDAC TME at the single-cell multiomics level, with an unbiased focus on the functions and potential classification bases of every cellular component within the TME, and look forward to the prospects of integrating single-cell multiomics data and retrospectively reusing bulk sequencing data, hoping to provide new insights into the PDAC TME.

Multiomics integration reveals NETosis heterogeneity and TLR2 as a prognostic biomarker in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant neoplasm characterized by a poor prognosis and limited therapeutic strategy. The PDAC tumor microenvironment presents a complex heterogeneity, where neutrophils emerge as the predominant constituents of the innate immune cell population. Leveraging the power of single-cell RNA-seq, spatial RNA-seq, and multi-omics approaches, we included both published datasets and our in-house patient cohorts, elucidating the inherent heterogeneity in the formation of neutrophil extracellular traps (NETs) and revealed the correlation between NETs and immune suppression. Meanwhile, we constructed a multi-omics prognostic model that suggested the patients exhibiting downregulated expression of NETs may have an unfavorable outcome. We also confirmed TLR2 as a potent prognosis factor and patients with low TLR2 expression had more effective T cells and an overall survival extension for 6 months. Targeting TLR2 might be a promising strategy to reverse immunosuppression and control tumor progression for an improved prognosis.

Engineering and Targeting Neutrophils for Cancer Therapy

Neutrophils are the most abundant white blood cells in the circulation and act as the first line of defense against infections. Increasing evidence suggests that neutrophils possess heterogeneous phenotypes and functional plasticity in human health and diseases, including cancer. Neutrophils play multifaceted roles in cancer development and progression, and an N1/N2 paradigm of neutrophils in cancer is proposed, where N1 neutrophils exert anti-tumor properties while N2 neutrophils display tumor-supportive and immune-suppressive functions. Selective activation of beneficial neutrophil population and targeted inhibition or re-polarization of tumor-promoting neutrophils has shown an important potential in tumor therapy. In addition, due to the natural inflammation-responsive and physical barrier-crossing abilities, neutrophils and their derivatives (membranes and extracellular vesicles (EVs)) are regarded as advanced drug delivery carriers for enhanced tumor targeting and improved therapeutic efficacy. In this review, the recent advances in engineering neutrophils for drug delivery and targeting neutrophils for remodeling tumor microenvironment (TME) are comprehensively presented. This review will provide a broad understanding of the potential of neutrophils in cancer therapy.

Cayratia albifolia C.L.Li exerts anti-rheumatoid arthritis effect by inhibiting macrophage activation and neutrophil extracellular traps (NETs)

BACKGROUND

Cayratia albifolia C.L.Li (CAC), commonly known as "Jiao-Mei-Gu" in China, has been extensively utilized by the Dong minority for several millennia to effectively alleviate symptoms associated with autoimmune diseases. CAC extract is believed to possess significant anti-inflammatory properties within the context of Dong medicine. However, an in-depth understanding of the specific pharmaceutical effects and underlying mechanisms through which CAC extract acts against rheumatoid arthritis (RA) has yet to be established.

METHODS

Twenty-four Sprague-Dawley rats were divided into four groups, with six rats in each group. To induce the collagen-induced arthritis (CIA) model, the rats underwent a process of double immunization with collagen and adjuvant. CAC extract (100 mg/kg) was orally administered to rats. The anti-RA effects were evaluated in CIA rats by arthritis score, hind paw volume and histopathology analysis. Pull-down assay was conducted to identify the potential targets of CAC extract from RAW264.7 macrophage lysates. Moreover, mechanism studies of CAC extract were performed by immunofluorescence assays, real-time PCR and Western blot.

RESULTS

CAC extract was found to obviously down-regulate hind paw volume of CIA rats, with diminished inflammation response and damage. 177 targets were identified from CAC extract by MS-based pull-down assay. Bioinformatics analysis found that these targets were mainly enriched in macrophage activation and neutrophils extracellular traps (NETs). Additionally, we reported that CAC extract owned significant anti-inflammatory activity by regulating PI3K-Akt-mTOR signal pathway, and inhibited NETosis in response to PMA.

CONCLUSIONS

We clarified that CAC extract significantly attenuated RA by inactivating macrophage and reducing NETosis via a multi-targets regulation.

Neutrophils as potential therapeutic targets for breast cancer

Breast cancer (BC) remains the foremost cause of cancer mortality globally, with neutrophils playing a critical role in its pathogenesis. As an essential tumor microenvironment (TME) component, neutrophils are emerging as pivotal factors in BC progression. Growing evidence has proved that neutrophils play a Janus- role in BC by polarizing into the anti-tumor (N1) or pro-tumor (N2) phenotype. Clinical trials are evaluating neutrophil-targeted therapies, including Reparixin (NCT02370238) and Tigatuzumab (NCT01307891); however, their clinical efficacy remains suboptimal. This review summarizes the evidence regarding the close relationship between neutrophils and BC, emphasizing the critical roles of neutrophils in regulating metabolic and immune pathways. Additionally, we summarize the existing therapeutic approaches that target neutrophils, highlighting the challenges, and affirming the rationale for continuing to explore neutrophils as a viable therapeutic target in BC management.

Targeting Neutrophil Extracellular Traps: A Novel Antitumor Strategy

The clinical efficacy of surgery, radiotherapy, and chemotherapy for cancer is usually limited by the deterioration of tumor microenvironment (TME). Neutrophil extracellular traps (NETs) are decondensed chromatin extruded by neutrophils and are widely distributed among various cancers, such as pancreatic cancer, breast cancer, and hepatocellular carcinoma. In the TME, NETs interact with stromal components, immune cells and cancer cells, which allows for the reshaping of the matrix and the extracellular environment that favors the initiation, progression, and metastasis of cancer. In addition, NETs impair the proliferation and activation of T cells and NK cells, thus producing a suppressive TME that restricts the effect of immunotherapy. A better understanding of the function of NETs in the TME will provide new opportunities for the prevention of cancer metastasis and the discovery of novel therapy strategies.

Melatonin, BAG-1 and cortisol circadian interactions in tumor pathogenesis and patterned immune responses

A dysregulated circadian rhythm is significantly associated with cancer risk, as is aging. Both aging and circadian dysregulation show suppressed pineal melatonin, which is indicated in many studies to be linked to cancer risk and progression. Another independently investigated aspect of the circadian rhythm is the cortisol awakening response (CAR), which is linked to stress-associated hypothalamus-pituitary-adrenal (HPA) axis activation. CAR and HPA axis activity are primarily mediated via activation of the glucocorticoid receptor (GR), which drives patterned gene expression via binding to the promotors of glucocorticoid response element (GRE)-expressing genes. Recent data shows that the GR can be prevented from nuclear translocation by the B cell lymphoma-2 (Bcl-2)-associated athanogene 1 (BAG-1), which translocates the GR to mitochondria, where it can have diverse effects. Melatonin also suppresses GR nuclear translocation by maintaining the GR in a complex with heat shock protein 90 (Hsp90). Melatonin, directly and/or epigenetically, can upregulate BAG-1, suggesting that the dramatic 10-fold decrease in pineal melatonin from adolescence to the ninth decade of life will attenuate the capacity of night-time melatonin to modulate the effects of the early morning CAR. The interactions of pineal melatonin/BAG-1/Hsp90 with the CAR are proposed to underpin how aging and circadian dysregulation are associated with cancer risk. This may be mediated via differential effects of melatonin/BAG-1/Hsp90/GR in different cells of microenvironments across the body, from which tumors emerge. This provides a model of cancer pathogenesis that better integrates previously disparate bodies of data, including how immune cells are regulated by cancer cells in the tumor microenvironment, at least partly via the cancer cell regulation of the tryptophan-melatonin pathway. This has a number of future research and treatment implications.