Methionine enkephalin (MENK) inhibits human gastric cancer through regulating tumor associated macrophages (TAMs) and PI3K/AKT/mTOR signaling pathway inside cancer cells

An update to experimental and clinical aspects of tumor-associated macrophages in cancer development: hopes and pitfalls

Tumor-associated macrophages (TAMs) represent one of the most abundant tumor-infiltrating stromal cells, and their normal function in tumor microenvironment (TME) is to suppress tumor cells by producing cytokines which trigger both direct cell cytotoxicity and antibody-mediated immune response. However, upon prolonged exposure to TME, the classical function of these so-called M1-type TAMs can be converted to another type, "M2-type," which are recruited by tumor cells so that they promote tumor growth and metastasis. This is the reason why the accumulation of TAMs in TME is correlated with poor prognosis in cancer patients. Both M1- and M2-types have high degree of plasticity, and M2-type cells can be reprogrammed to M1-type for therapeutic purposes. This characteristic introduces TAMs as promising target for developing novel cancer treatments. In addition, inhibition of M2-type cells and blocking their recruitment in TME, as well as their depletion by inducing apoptosis, are other approaches for effective immunotherapy of cancer. In this review, we summarize the potential of TAMs to be targeted for cancer immunotherapy and provide an up-to-date about novel strategies for targeting TAMs.

Tramadol suppresses growth of orthotopic liver tumors via promoting M1 macrophage polarization in the tumor microenvironment

Tumor-associated macrophages (TAMs) are major infiltrating immune cells in liver cancer. They are polarized to anti-tumor M1 type or tumor-supporting M2 type in a dynamic changing state. Tramadol, a synthetic opioid, exhibits tumor-suppressing effect in several cancers, but whether it plays a role in TAMs polarization is uncertain. In the present study, the potential influence of tramadol on TAMs polarization was explored in liver cancer. An orthotopic murine Hepa 1-6 liver cancer model was constructed. The potential function of tramadol was evaluated by cell viability assay, EdU incorporation assay, flow cytometry, immunofluorescence, quantitative real-time polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA) assay, T cell proliferation and suppression assays and western blot. We found that tramadol suppressed proliferation and tumor formation of murine Hepa 1-6 cells in vitro and in vivo. Tramadol reprogramed the immune microenvironment to favor M1 macrophage polarization in orthotopic Hepa 1-6 tumors. Moreover, tramadol facilitated M1 macrophage polarization and inhibited M2 macrophage polarization of bone marrow-derived macrophages (BMDMs) and human THP-1 macrophages in vitro. Furthermore, tramadol-treated BMDMs promoted proliferation and activation of splenic CD4+ and CD8+ T cells. Tramadol induced cellular ROS production and mitochondrial dysfunction of BMDMs. Finally, tramadol activated NF-κB signaling in BMDMs and THP-1 macrophages, while inhibition of NF-κB signaling by JSH-23 attenuated the influence of tramadol on macrophage polarization. In conclusion, these data elucidated a novel anti-tumor mechanism of tramadol in liver cancer. Tramadol might be a promising treatment strategy for liver cancer patients.

Methionine enkephalin (MENK) protected macrophages from ferroptosis by downregulating HMOX1 and ferritin

OBJECTIVE

The aim of this work was to investigate the immunological effect of MENK by analyzing the protein spectrum and bioinformatics of macrophage RAW264.7, and to explore the relationship between macrophage and ferroptosis.

RESULT

We employed proteomic analysis to identify differentially expressed proteins (DEPs) between macrophages and macrophages intervened by MENK. A total of 208 DEPs were identified. Among these, 96 proteins had upregulated expression and 112 proteins had downregulated expression. Proteomic analysis revealed a significant enrichment of DEPs associated with iron metabolism. The identification of hub genes was conducted using KEGG pathway diagrams and protein-protein interaction (PPI) analysis. The hub genes identified in this study include HMOX1 and Ferritin (FTH and FTL). A correlation was established between HMOX1, FTH, and FTL in the GO and KEGG databases. The results of PCR, WB and immunofluorescence showed that MENK downregulated the level of HMOX1 and FTH.

CONCLUSION

MENK had the potential to become an adjuvant chemotherapy drug by regulating iron metabolism in macrophages, reducing levels of HMOX1 and ferritin. We proposed an innovative research direction on the therapeutic potential of MENK, focusing on the relationship between ferroptosis and macrophage activity.

The Opioid Growth Factor in Growth Regulation and Immune Responses in Cancer

It has become apparent that endogenous opioids act not only as neurotransmitters and neuromodulators, but have multiple functions in the body. Activation of the opioid system by opiate drugs is associated with a risk of cancer development through direct stimulation of tumor cell proliferation and through immunosuppression. In contrast, the endogenous peptide opioid [Met5]-enkephalin, now commonly referred to as Opioid Growth Factor (OGF), negatively regulates cell proliferation in a wide number of cells during development, homeostasis, and neoplasia. This action is mediated through the opioid growth factor receptor, originally designated the zeta (ζ) opioid receptor. Further, contrary to the traditional notion of opiates as immunosuppressive, endogenous OGF has been shown to possess a number of positive immunomodulatory properties and may provide a beneficial effect in cancer by augmenting the activity of cells involved in both innate and acquired immunity. Taken together, the evidence supports consideration of opioid peptides such as OGF as new strategies for cancer therapy.

Methionine enkephalin inhibited cervical cancer migration as well as invasion and activated CD11b+ NCR1+ NKs of tumor microenvironment

This study was to study the role of methionine enkephalin (menk) in cell invasion and migration as well as NK cells activation of tumor microenvironment in cervical cancer. The results showed that menk inhibited cervical cancer migration and invasion. In addition, we found menk affected epithelial to mesenchymal transition (EMT) related indicators, with increasing E-cadherin level, decreasing N-cadherin and vimentin level. Through in vivo mouse model, we found that menk IFNγ and NKP46 expression was upregulated in tumor tissues by menk compared with controls, while LAG3 expression was inhibited by menk, besides, there was an upregulation of CD11b+ NCR1+ NKs of tumor microenvironment in cervical cancer. Therefore, we concluded that menk inhibited cancer migration and invasion via affecting EMT related indicators and activated CD11b+ NCR1+ NKs of tumor microenvironment in cervical cancer, laying a theoretical foundation for the further clinical treatment of menk.

Involvement of the Opioid Peptide Family in Cancer Progression

Peptides mediate cancer progression favoring the mitogenesis, migration, and invasion of tumor cells, promoting metastasis and anti-apoptotic mechanisms, and facilitating angiogenesis/lymphangiogenesis. Tumor cells overexpress peptide receptors, crucial targets for developing specific treatments against cancer cells using peptide receptor antagonists and promoting apoptosis in tumor cells. Opioids exert an antitumoral effect, whereas others promote tumor growth and metastasis. This review updates the findings regarding the involvement of opioid peptides (enkephalins, endorphins, and dynorphins) in cancer development. Anticancer therapeutic strategies targeting the opioid peptidergic system and the main research lines to be developed regarding the topic reviewed are suggested. There is much to investigate about opioid peptides and cancer: basic information is scarce, incomplete, or absent in many tumors. This knowledge is crucial since promising anticancer strategies could be developed alone or in combination therapies with chemotherapy/radiotherapy.

Role of tumor-associated macrophages in common digestive system malignant tumors

Many digestive system malignant tumors are characterized by high incidence and mortality rate. Increasing evidence has revealed that the tumor microenvironment (TME) is involved in cancer initiation and tumor progression. Tumor-associated macrophages (TAMs) are a predominant constituent of the TME, and participate in the regulation of various biological behaviors and influence the prognosis of digestive system cancer. TAMs can be mainly classified into the antitumor M1 phenotype and protumor M2 phenotype. The latter especially are crucial drivers of tumor invasion, growth, angiogenesis, metastasis, immunosuppression, and resistance to therapy. TAMs are of importance in the occurrence, development, diagnosis, prognosis, and treatment of common digestive system malignant tumors. In this review, we summarize the role of TAMs in common digestive system malignant tumors, including esophageal, gastric, colorectal, pancreatic and liver cancers. How TAMs promote the development of tumors, and how they act as potential therapeutic targets and their clinical applications are also described.

Proteomics analysis of methionine enkephalin upregulated macrophages against infection by the influenza-A virus

Macrophages have a vital role in phagocytosis and antiviral effect against invading influenza viruses. Previously, we found that methionine enkephalin (MENK) inhibited influenza virus infection by upregulating the "antiviral state" of macrophages. To investigate the immunoregulatory mechanism of action of MENK on macrophages, we employed proteomic analysis to identify differentially expressed proteins (DEPs) between macrophages infected with the influenza-A virus and cells infected with the influenza-A virus after pretreatment with MENK. A total of 215 DEPs were identified: 164 proteins had upregulated expression and 51 proteins had downregulated expression. Proteomics analysis showed that DEPs were highly enriched in "cytokine-cytokine receptor interaction", "phagosome", and "complement and coagulation cascades pathway". Proteomics analysis revealed that MENK could be an immune modulator or prophylactic for the prevention and treatment of influenza. MENK promoted the polarization of M1 macrophages, activated inflammatory responses, and enhanced phagocytosis and killing function by upregulating opsonizing receptors.

Tumor microenvironment-mediated immune tolerance in development and treatment of gastric cancer

Tumor microenvironment is the general term for all non-cancer components and their metabolites in tumor tissue. These components include the extracellular matrix, fibroblasts, immune cells, and endothelial cells. In the early stages of tumors, the tumor microenvironment has a tumor suppressor function. As the tumor progresses, tumor immune tolerance is induced under the action of various factors, such that the tumor suppressor microenvironment is continuously transformed into a tumor-promoting microenvironment, which promotes tumor immune escape. Eventually, tumor cells manifest the characteristics of malignant proliferation, invasion, metastasis, and drug resistance. In recent years, stress effects of the extracellular matrix, metabolic and phenotypic changes of innate immune cells (such as neutrophils, mast cells), and adaptive immune cells in the tumor microenvironment have been revealed to mediate the emerging mechanisms of immune tolerance, providing us with a large number of emerging therapeutic targets to relieve tumor immune tolerance. Gastric cancer is one of the most common digestive tract malignancies worldwide, whose mortality rate remains high. According to latest guidelines, the first-line chemotherapy of advanced gastric cancer is the traditional platinum and fluorouracil therapy, while immunotherapy for gastric cancer is extremely limited, including only Human epidermal growth factor receptor 2 (HER-2) and programmed death ligand 1 (PD-L1) targeted drugs, whose benefits are limited. Clinical experiments confirmed that cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), vascular endothelial growth factor receptor (VEGFR) and other targeted drugs alone or in combination with other drugs have limited efficacy in patients with advanced gastric cancer, far less than in lung cancer, colon cancer, and other tumors. The failure of immunotherapy is mainly related to the induction of immune tolerance in the tumor microenvironment of gastric cancer. Therefore, solving the immune tolerance of tumors is key to the success of gastric cancer immunotherapy. In this study, we summarize the latest mechanisms of various components of the tumor microenvironment in gastric cancer for inducing immune tolerance and promoting the formation of the malignant phenotype of gastric cancer, as well as the research progress of targeting the tumor microenvironment to overcome immune tolerance in the treatment of gastric cancer.

Methionine enkephalin inhibits colorectal cancer by remodeling the immune status of the tumor microenvironment

There is evidence that methionine enkephalin (MENK), an opioid peptide, promotes anti-tumor immune responses. In this study, the effect of MENK on colorectal cancer (CRC) and its mechanisms of action were examined in vivo. The intraperitoneal administration of 20 mg/kg MENK effectively inhibited MC38 subcutaneous colorectal tumor growth in mice. MENK inhibited tumor progression by increasing the immunogenicity and recognition of MC38 cells. MENK down-regulated the oncogene Kras and anti-apoptotic Bclxl and Bcl2, suppressed Il1b, Il6, iNOS, and Arg1 (encoding inflammatory cytokines), and increased Il17a and Il10 levels. MENK promoted a tumor suppressive state by decreasing the immune checkpoints Pd-1, Pd-l1, Lag3, Flgl1, and 2b4 in CRC. MENK also altered the immune status of the tumor immune microenvironment (TIME). It increased the infiltration of M1-type macrophages, CD8⁺T cells, and CD4⁺T cells and decreased the proportions of G-MDSCs, M-MDSCs, and M2-type macrophages. MENK accelerated CD4⁺T_EM and CD8⁺T_EM cell activation in the TIME and up-regulated IFN-γ, TNF-α, and IL-17A in CD4⁺T cells and Granzyme B in CD8⁺T cells. In addition, analyses of PD-1 and PD-L1 expression indicated that MENK promoted the anti-tumor immune response mediated by effector T cells. Finally, OGFr was up-regulated at the protein and mRNA levels by MENK, and the inhibitory effects of MENK on tumor growth were blocked by NTX, a specific blocker of OGFr. These finding indicate that MENK remodels the TIME in CRC to inhibit tumor progression by binding to OGFr. MENK is a potential therapeutic agent for CRC, especially for improving the efficacy of immunotherapy.

Emerging Roles of the Nervous System in Gastrointestinal Cancer Development

Simple Summary

Nerve–cancer cross-talk has increasingly become a focus of the oncology field, particularly in gastrointestinal (GI) cancers. The indispensable roles of the nervous system in GI tumorigenesis and malignancy have been dissected by epidemiological, experimental animal and mechanistic data. Herein, we review and integrate recent discoveries linking the nervous system to GI cancer initiation and progression, and focus on the molecular mechanisms by which nerves and neural receptor pathways drive GI malignancy.

Abstract

Our understanding of the fascinating connection between nervous system and gastrointestinal (GI) tumorigenesis has expanded greatly in recent years. Recent studies revealed that neurogenesis plays an active part in GI tumor initiation and progression. Tumor-driven neurogenesis, as well as neurite outgrowth of the pre-existing peripheral nervous system (PNS), may fuel GI tumor progression via facilitating cancer cell proliferation, chemoresistance, invasion and immune escape. Neurotransmitters and neuropeptides drive the activation of various oncogenic pathways downstream of neural receptors within cancer cells, underscoring the importance of neural signaling pathways in GI tumor malignancy. In addition, neural infiltration also plays an integral role in tumor microenvironments, and contributes to an environment in favor of tumor angiogenesis, immune evasion and invasion. Blockade of tumor innervation via denervation or pharmacological agents may serve as a promising therapeutic strategy against GI tumors. In this review, we summarize recent findings linking the nervous system to GI tumor progression, set the spotlight on the molecular mechanisms by which neural signaling fuels cancer aggressiveness, and highlight the importance of targeting neural mechanisms in GI tumor therapy.

CTHRC1 is a Potential Prognostic Biomarker and Correlated with Macrophage Infiltration in Breast Cancer

Background

Tumor immune cell infiltration is closely associated with the occurrence and development of tumors. Collagen triple helix repeats containing 1 (CTHRC1), a regulator of collagen expression and cell migration, is involved in the metastasis and invasion of tumors. However, the role of CTHRC1 in breast cancer remains unclear. This study aimed to investigate the prognostic value of CTHRC1, and further explore its association with immune infiltration in breast cancer.

Methods

CTHRC1 expression pattern and prognostic value were analyzed using ONCOMINE, PrognoScan, GEPIA, and Kaplan–Meier Plotter databases. We then detected CTHRC1 mRNA levels in breast cancer tissues and paired normal breast tissues by Q-PCR. Subsequently, the University of California Santa Cruz (UCSC) database was used to determine the methylation status of CTHRC1. Furthermore, CTHRC1 mutations were investigated using the Catalogue of Somatic mutations in Cancer (COSMIC) and cBioPortal databases. We also assessed the correlation between CTHRC1 expression and immune cell infiltration using TIMER. In addition, The relationship of CTHRC1 expression with the immune marker sets of various immune cells was evaluated using GEPIA and TIMER.

Results

CTHRC1 was highly expressed in a variety of tumors, including breast cancer. Elevated CTHRC1 expression was related to a poor prognosis. Notably, CTHRC1 expression was significantly associated with macrophage infiltration, especially the immune infiltration gene marker set of M2. Copy number variations, DNA mutations and methylation states might be potential mechanisms for regulating CTHRC1 expression. Protein digestion and absorption, human papillomavirus infection, ECM-receptor interaction, focal adhesion, and PI3K-Akt signaling pathways were identified as the potential CTHRC1-driven signaling pathways.

Conclusion

These findings suggest that CTHRC1 could be a promising immune-related biomarker for the treatment of breast cancer patients.

Methionine enkephalin inhibited cervical carcinoma via apoptosis promotion and reduction of myeloid derived suppressor cell infiltrated in tumor

Immunotherapy for cervical carcinoma is becoming increasingly important recently. In these studies methionine enkephalin (menk) is shown to inhibit cervical tumor cell proliferation in vitro in association with an increase in the expression of apoptosis markers and mediators, including an increase in fas, caspase 8, and caspase 3 expression and intrinsic expression of the signaling pathway mediator bax. In vivo, tumor growth was restrained in mice xenotransplant model with typical pathological features of apoptosis. Furthermore, myeloid derived suppressor cells (MDSCs) had a significant decrease in circulation and in tumor site. In brief, these findings showed menk could inhibit tumor growth in vitro and in vivo, providing direction of further research and clinical application prospect.

Opioids Regulate the Immune System: Focusing on Macrophages and Their Organelles

Opioids are the most widely used analgesics and therefore have often been the focus of pharmacological research. Macrophages are the most plastic cells in the hematopoietic system. They show great functional diversity in various organism tissues and are an important consideration for the study of phagocytosis, cellular immunity, and molecular immunology. The expression of opioid receptors in macrophages indicates that opioid drugs act on macrophages and regulate their functions. This article reviewed the collection of research on effects of opioids on macrophage function. Studies show that opioids, both endogenous and exogenous, can affect the function of macrophages, effecting their proliferation, chemotaxis, transport, phagocytosis, expression of cytokines and chemokine receptors, synthesis and secretion of cytokines, polarization, and apoptosis. Many of these effects are closely associated with mitochondrial function and functions of other organelles in macrophages. Therefore, in depth research into effects of opioids on macrophage organelles may lead to some interesting new discoveries. In view of the important role of macrophages in HIV infection and tumor progression, this review also discusses effects of opioids on macrophages in these two pathological conditions.

Research progress of opioid growth factor in immune-related diseases and cancer diseases

Methionine enkephalin (MENK) has an important role in both neuroendocrine and immune systems. MENK was known as an opioid growth factor (OGF) for its growth regulatory characteristics. OGF interacts with the OGF receptor (OGFr) to inhibit DNA synthesis by upregulating p16 and/or p21, which delays the cell cycle transition from G0/G1 to S phase, and inhibits cell proliferation. In addition, OGF combines with OGFr in immune cells to exert its immunomodulatory activity and regulate immune function. OGF has been studied as an immunomodulator in a variety of autoimmune diseases, including multiple sclerosis, inflammatory bowel disease, diabetes and viral infections, and has been proven to relieve symptoms of certain diseases in animal and in vitro experiments. Also, OGF and OGFr have various anti-tumor molecular mechanisms. OGF can be used as the primary therapy alone or combined with other drugs to treat tumors. This article summarizes the research progress of OGF in immune-related diseases and cancer diseases.

A novel mechanism of lung cancer inhibition by methionine enkephalin through remodeling the immune status of the tumor microenvironment

This study examined the antitumor effect of methionine enkephalin (MENK) against lung cancer in vivo and in vitro and explored the underlying mechanisms. Changes in the immune status of the tumor microenvironment (TME) in response to MENK administration were examined in mice. MENK significantly inhibited the proliferation of lung cancer cells in vivo and in vitro by regulating the Wnt/β-catenin pathway and causing cell cycle arrest at the G0/G1 phase. Knockdown of opioid growth factor receptor abolished the effect of MENK on lung cancer cells. The immune status of the TME of mice differed between the MENK and control groups. MENK increased the infiltration of M1-type macrophages, natural killer cells, CD8+ T cells, CD4+ T cells, and dendritic cells into the TME, and decreased the proportion of myeloid inhibitory cells and M2-type macrophages. Immunohistochemical analysis of the expression of cytokines in the TME showed that MENK upregulated IL-15, IL-21, IFN-γ, and granzyme B and downregulated IL-10 and TGF-β1 in mice. Taken together, these finding indicate that MENK may be a potential agent for lung cancer treatment in the future, especially for overcoming immune escape and immune resistance.

Babao Dan Reverses Multiple-Drug Resistance in Gastric Cancer Cells via Triggering Apoptosis and Autophagy and Inhibiting PI3K/AKT/mTOR Signaling

Multidrug resistance (MDR) is a critical reason for cancer chemotherapy failure. Babaodan (BBD) is a famous traditional Chinese patent medicine reported to have antigastric cancer activity. However, the roles and molecular mechanisms of the reversal of MDR of gastric cancer by BBD have not been well described until now. Therefore, the purpose of this study was to elucidate further the role of BBD in reversing the MDR of gastric cancer cells and its specific regulatory mechanism via in vitro experiments. To verify our results, MTT, Doxorubicin (DOX) staining, Rhodamin123 (Rho123) staining, DAPI staining, Annexin V-FITC, propidium iodide (PI), Cyto-ID, and western blot assays were performed. To determine whether BBD triggers apoptosis and autophagy through the PI3K/AKT/mTOR signaling, we also applied 3-methyladenine (3-MA), chloroquine (CQ), and 740Y-P (an activator of PI3K). The results showed that BBD reversed the MDR and induced apoptosis and autophagy of SGC7901/DDP cells. Pathway analyses suggested BBD inhibits PI3K/AKT/mTOR pathway activity and subsequent apoptosis-autophagy induction. Inhibition of autophagy with 3-MA and chloroquine (CQ) was performed to confirm that BBD promoted autophagy. PI3K agonist, 740Y-P, further verified BBD inhibition of PI3K/AKT/mTOR pathway activation. In conclusion, BBD may reverse the MDR of gastric cancer cells, induce apoptosis, and promote autophagy via inactivation of the PI3K/AKT/mTOR signaling pathway.

Methionine enkephalin (MENK) suppresses lung cancer by regulating the Bcl-2/Bax/caspase-3 signaling pathway and enhancing natural killer cell-driven tumor immunity

The aim of this study was to investigate how methionine enkephalin (MENK) regulates the biological behavior of lung cancer cells and to further explore its anti-lung cancer mechanisms in vitro and in vivo. The results showed that MENK enhanced the expression of opioid receptor (OGFr) and induced apoptosis of lung cancer cells by activating the Bcl-1/Bax/caspase-3 signaling pathway in vitro and in vivo. However, the regulatory effects of MENK disappeared after blockade of the OGFr. This confirmed that a prerequisite for the anti-tumor action of MENK is binding to OGFr. Additionally, we observed that MENK treatment enhanced the immunogenicity of lung cancer by enhancing the exposure of calreticulin and high mobility group box 1, and increasing the expression of NKG2D ligands. Further studies showed that MENK treatment increased the expression of natural killer (NK) cell-related cytokines such as granzyme B and interferon-γ and NK cell activation. Thus, we concluded that MENK might inhibit the proliferation of lung cancer cells by activating the Bcl-2/Bax/caspase-3 signaling pathway and enhancing immunogenicity and NK cell-driven tumor immunity.

Methionine enkephalin activates autophagy and stimulates tumour cell immunogenicity in human cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (CSCC) is a common skin tumour. Due to weak immunogenicity, recurrence is frequent after treatment. In this study, we explored the effects and mechanisms of methionine enkephalin (MENK), an endogenous opioid peptide and negative growth regulator, in CSCC. MENK inhibited A431 cell proliferation and promoted apoptosis through the opioid growth factor receptor (OGFr). Importantly, MENK also induced autophagy in CSCC and stimulated the emission of DAMPs in A431 cells, which resulted in enhanced activation of dendritic cells (DC).In conclusion, MENK provides an effective method with therapeutic potential to modulate the CSCC microenvironment by utilizing autophagy in the cancer cells.

Ganoderma lucidum Spore Polysaccharide Inhibits the Growth of Hepatocellular Carcinoma Cells by Altering Macrophage Polarity and Induction of Apoptosis

Background

Ganoderma lucidum has certain components with known pharmacological effects, including strengthening immunity and anti-inflammatory activity. G. lucidum seeds inherit all its biological characteristics. G. lucidum spore polysaccharide (GLSP) is the main active ingredient to enhance these effects. However, its specific biological mechanisms are not exact. Our research is aimed at revealing the specific biological mechanism of GLSP to enhance immunity and inhibit the growth of H22 hepatocellular carcinoma cells.

Methods

We extracted primary macrophages (Mø) from BALB/c mice and treated them with GLSP (800 μg/mL, 400 μg/mL, and 200 μg/mL) to observe its effects on macrophage polarization and cytokine secretion. We used GLSP and GLSP-intervened macrophage supernatant to treat H22 tumor cells and observed their effects using MTT and flow cytometry. Moreover, real-time fluorescent quantitative PCR and western blotting were used to observe the effect of GLSP-intervened macrophage supernatant on the PI3K/AKT and mitochondrial apoptosis pathways.

Results

In this study, GLSP promoted the polarization of primary macrophages to M1 type and the upregulation of some cytokines such as TNF-α, IL-1β, IL-6, and TGF-β1. The MTT assay revealed that GLSP+Mø at 400 μg/mL and 800 μg/mL significantly inhibited H22 cell proliferation in a dose-dependent manner. Flow cytometry analysis revealed that GLSP+Mø induced apoptosis and cell cycle arrest at the G2/M phase, associated with the expression of critical genes and proteins (PI3K, p-AKT, BCL-2, BAX, and caspase-9) that regulate the PI3K/AKT pathway and apoptosis. GLSP reshapes the tumor microenvironment by activating macrophages, promotes the polarization of primary macrophages to M1 type, and promotes the secretion of various inflammatory factors and cytokines.

Conclusion

Therefore, as a natural nutrient, GLSP is a potential agent in hepatocellular carcinoma cell treatment and induction of apoptosis.

The role of macrophage in regulating tumour microenvironment and the strategies for reprogramming tumour-associated macrophages in antitumour therapy

Tumour-associated macrophages (TAMs) that present abundantly in the tumour microenvironment (TME) exhibit a protumour property, such as promoting genetic instability, tumour metastasis and immunosuppression. Macrophage-targeted therapeutic approaches hence have been applied and shown their significances in the process of tumour immune treatment, including blocking TAM recruitment, depleting or transforming TAMs that already exist in the tumour site. Here, we summarized the functional regulation of TAMs in the respects of hypoxia environment, metabolism in the tumour microenvironment and the transcription factors involved. We reviewed the strategies for transforming TAMs, including immune stimuli targeting TAMs, inhibitors against TAMs, pathogen or irradiation stimulation on TAMs, and the application of natural compounds in TAMs. Furthermore, we also discussed the macrophage-targeted therapies in the clinical studies. Taken together, this review tries to shed light on the TAM regulation and the main strategies of TAM reprogramming for an enhanced immune surveillance.

New insights into molecular pathways in colorectal cancer: Adiponectin, interleukin-6 and opioid signaling

Colorectal cancer (CRC) is one of the most common cause of death among neoplasms around the world. The environmental factors, like diet and obesity, are crucial in CRC pathogenesis by creating cancer-favorable microenvironment and hormonal changes. Adiponectin, the adipose tissue-specific hormone, is generally considered to negatively correlate with CRC development. The interleukin 6 (IL-6) is one of the most important pro-inflammatory cytokine connected with CRC, which is strongly inflammation-associated. The opioids are variable group substantially correlated with cancers - the endogenous opioids affect immune system and cell cycle including proliferation and cell death whereas exogenous opioids are leading clinically used analgesics in terminal cancer patients. In this review we discuss the involvement of adiponectin, IL-6 and opioids in CRC pathogenesis, their link with obesity, possible cross-talk and potential novel therapeutic approach in CRC treatment.

Intraoperative opioids are associated with improved recurrence-free survival in triple-negative breast cancer

BACKGROUND

Opioid-induced immunomodulation may be of particular importance in triple-negative breast cancer (TNBC) where an immune response is associated with improved outcome and response to immunotherapy. We evaluated the association between intraoperative opioids and oncological outcomes and explored patterns of opioid receptor expression in TNBC.

METHODS

Consecutive patients with stage I-III primary TNBC were identified from a prospectively maintained database. Opioid receptor expression patterns in the tumour microenvironment were analysed using publicly available bulk and single-cell RNA-seq data.

RESULTS

A total of 1143 TNBC cases were retrospectively analysed. In multivariable analysis, higher intraoperative opioid dose was associated with favourable recurrence-free survival, hazard ratio 0.93 (95% confidence interval 0.88-0.99) per 10 oral morphine milligram equivalents increase (P=0.028), but was not significantly associated with overall survival, hazard ratio 0.96 (95% confidence interval 0.89-1.02) per 10 morphine milligram equivalents increase (P=0.2). Bulk RNA-seq analysis of opioid receptors showed that OPRM1 was nearly non-expressed. Compared with normal breast tissue OGFR, OPRK1, and OPRD1 were upregulated, while TLR4 was downregulated. At a single-cell level, OPRM1 and OPRD1 were not detectable; OPRK1 was expressed mainly on tumour cells, whereas OGFR and TLR4 were more highly expressed on immune cells.

CONCLUSIONS

We found a protective effect of intraoperative opioids on recurrence-free survival in TNBC. Opioid receptor expression was consistent with a net protective effect of opioid agonism, with protumour receptors either not expressed or downregulated, and antitumour receptors upregulated. In this era of personalised medicine, efforts to differentiate the effects of opioids across breast cancer subtypes (and ultimately individual patients) should continue.

Preliminary study of mechanisms of intestinal inflammation induced by plant proteins in juvenile hybrid groupers (♀Epinephelus fuscoguttatus×♂E. lanceolatu)

Fish fed a high plant protein diet exhibit intestinal inflammation, the mechanism of which needs to be clarified. We preliminarily elucidate the mechanism of the TLRs/MyD88-PI₃K/Akt signalling pathway in intestinal inflammation induced by plant proteins. The diets contained 60% fish meal (FM, controls), or had 45% of the fish meal protein replaced by soybean meal (SBM), peanut meal (PM), cottonseed meal (CSM) or cottonseed protein concentrate (CPC). After an 8-week feeding trial, fish were challenged by injection of Vibrio parahaemolyticus bacteria for 7 days until the fish stabilized. The results showed that the specific growth rate (SGR) of the FM group was higher than other groups. The SGR of the CPC group was higher than those of the SBM, PM and CSM groups. The catalase (CAT) contents in the serum of fish fed a plant protein diet were higher than in FM fish. The abundances of Rhodobacteraceae and Microbacteriaceae in the MI (mid intestine) were higher in the CPC group. The TLR-2 expressions in the MI and DI of plant protein-fed fish were up-regulated. The expressions of IL-6 in the PI and MI, of hepcidin and TLR-3 in the MI, and of TLR-3 in the DI, were all lower than those of fish fed FM. In the PI, MI and DI, the protein expressions of P-PI₃K/T-PI₃K in the SBM and PM groups were higher than in the FM group. After the challenge, the cumulative mortalities in the FM and CPC groups were lower than those of the SBM, PM and CSM groups. These results suggested that plant protein diets reduced antioxidant capacity and glycolipid metabolism, hindered the development of the intestine and reduced intestinal flora diversity. TLR-3 is involved in the immune regulation of the PI in CPC group, MI and DI in SBM, PM, CSM and CPC groups, while might be involved in the immune regulation of the PI in SBM, PM and CSM groups. Furthermore, PI₃K/Akt signaling does not participate in the regulation of PI and MI in the CSM group, MI and DI in the CPC group.

Molecular biology and immunology of gastric cancer peritoneal metastasis

Peritoneal metastases occur in 55-60% of patients with gastric cancer (GC) and are associated with a 2% 5-year overall survival rate. There are limited treatment options for these patients, and no targeted therapy or immunotherapy is available. Rational therapeutic targets remain to be found. In this review, we present the published literature and our own recent experience in molecular biology to identify important molecules and signaling pathways as well as cellular immunity involved in the peritoneal metastasis of GC. We also suggest potential novel strategies for improving the outcomes of GC patients with peritoneal metastasis.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).

Exploring microRNAs in diabetic chronic cutaneous ulcers: Regulatory mechanisms and therapeutic potential

Diabetic chronic cutaneous ulcers (DCU) are one of the serious complications of diabetes mellitus, occurring mainly in diabetic patients with peripheral neuropathy. Recent studies have indicated that microRNAs (miRNAs/miRs) and their target genes are essential regulators of cell physiology and pathology including biological processes that are involved in the regulation of diabetes and diabetes-related microvascular complications. in vivo and in vitro models have revealed that the expression of some miRNAs can be regulated in the inflammatory response, cell proliferation, and wound remodelling of DCU. Nevertheless, the potential application of miRNAs to clinical use is still limited. Here, we provide a contemporary overview of the miRNAs as well as their associated target genes and pathways (including Wnt/β-catenin, NF-κB, TGF-β/Smad, and PI3K/AKT/mTOR) related to DCU healing. We also summarize the current development of drugs for DCU treatment and discuss the therapeutic challenges of DCU treatment and its future research directions.

Celastrus Orbiculatus Extracts Inhibit the Metastasis through Attenuating PI3K/Akt/mTOR Signaling Pathway in Human Gastric Cancer

BACKGROUND

Rapamycin receptor inhibitors have been applied in the clinic and achieved satisfactory therapeutic effect recently. The mechanisms did not clearly show how the Celastrus Orbiculatus Extracts (COE) inhibited the expression of the mammalian Target of Rapamycin (mTOR) in human gastric cancer cells. The aim of this study was to investigate whether the COE inhibited the metastasis through the mTOR signaling pathway in human gastric cancer MGC-803 cells.

METHODS

The abnormal expression level of mTOR protein was detected by immunohistochemistry in human gastric cancer tissue. The MGC-803/mTOR- cells were constructed by knockdown of mTOR using lentivirus infection technique. The human gastric cancer MGC-803/mTOR- cells were treated with different concentrations (20, 40, 80 μg/ml) of COE for 24 hours. The ability of cell metastasis was analyzed by the cell invasion and migration assay. The expression levels of PI3K/Akt/mTOR signaling pathway were detected by Western Blotting.

RESULTS

COE inhibited the proliferation, invasion and migration of MGC-803/mTOR- cells in a concentrationdependent manner. The expression of E-cadherin protein increased, and the expression of N-cadherin and Vimentin decreased simultaneously in the MGC-803/mTOR- cells. 4EBP1, p-4EBP1, P70S6k, p-P70S6k, mTOR, p-mTOR, PI3K and Akt proteins in MGC-803/mTOR- cells were reduced in a dose-dependent manner.

CONCLUSION

COE could not only inhibit cell growth, invasion and migration, but also inhibit the epithelialmesenchymal transition of gastric cancer cells. The molecular mechanism of COE inhibited the metastasis which may be related to the PI3K/Akt/mTOR signal pathway. This study provides ideas for the development of new anti-gastric cancer drugs.

Methionine enkephalin inhibits influenza A virus infection through upregulating antiviral state in RAW264.7 cells

MENK, as an immune adjuvant, has potential immune-regulatory activity on innate and adaptive immune cells. The aim of this work was to investigate the antiviral effect of MENK on influenza virus-infected murine macrophage cells (RAW264.7) and its underlying mechanisms. The results showed that MENK markedly inhibited influenza A virus (H1N1) replication in pre- and post-MENK treatment, especially in pre-MENK treatment. The mechanisms exploration revealed that MENK (10 mg/mL) significantly inhibited the nucleoprotein (NP) of influenza virus and up-regulated levels of IL-6, TNF-α and IFN-β compared with those in H1N1 control group. Further experiments confirmed that antiviral effects of MENK was associated with promotion of opioid receptor (MOR) as well as activation of NF-κB p65 inducing cellular antiviral status. The data suggest that MENK should be potential candidate for prophylactic or therapeutic treatment against H1N1 influenza virus.

SIRT4 silencing in tumor-associated macrophages promotes HCC development via PPARδ signalling-mediated alternative activation of macrophages

Background

The activation of tumour-associated macrophages (TAMs) contributes to the progression of hepatocellular carcinoma (HCC). SIRT4 acts as a tumour suppressor of tumour growth by regulating cell metabolism, inflammation, and anti-tumourigenesis. However, the involvement of SIRT4 in the activation of TAMs is unknown. Based on previous findings, the expression of SIRT4 in distinct groups of TAMs as well as the effect of SIRT4 silencing on macrophage polarization was investigated.

Methods

The expression of SIRT4 in HCC tissues and peritumour tissues was tested by qRT-PCR, western blotting and histological analysis. A Kaplan-Meier survival curve was generated based on the expression of SIRT4 in the HCC samples. Next, immunofluorescence staining was used to evaluate distinct groups of TAMs in human HCC samples, and the expression of SIRT4 in M1 and M2 TAMs was examined by flow cytometry. A homograft mouse model was used to assess the effect of SIRT4 silencing in TAMs on the development of HCC cells.

Results

SIRT4 was significantly downregulated in HCC tumour tissues, and the expression of SIRT4 in peritumour tissues was positively associated with survival in patients. We further found that downregulation of SIRT4 was associated with increased macrophage infiltration and a high ratio of M2/M1 macrophages in HCC peritumour tissues. Using gene interference, we found that SIRT4 silencing in TAMs significantly modulated the alternative activation of macrophages and promoted in vitro and in vivo HCC cell growth. Mechanistically, we revealed that HCM restricted the expression of SIRT4 in macrophages and promoted alternative activation of macrophages via the FAO-PPARδ-STAT3 axis. Furthermore, we also revealed that elevated MCP-1 expression induced by SIRT4 downregulation was responsible for increased TAM infiltration in peritumour tissues.

Conclusions

Overall, our results demonstrate that downregulation of SIRT4 in TAMs modulates the alternative activation of macrophages and promotes HCC development via the FAO-PPARδ-STAT3 axis. These results could provide a new therapeutic target for the treatment of HCC.

Prospective oncotarget for gynecological cancer: Opioid growth factor (OGF) - opioid growth factor receptor (OGFr) axis

The standard treatments for neoplasia include surgery, chemotherapy, hormone antagonists and radiotherapy, which can prolong survival, but rarely cure the tumors of gynecological cancer patients. OGF - OGFr expression, in various gynecologic cells and tissues, is an intersection point between cell development, neuroendocrine function and immune modulation. It has been identified that OGF and OGFr expression differs between gynecological tumor and normal cells. Further, exogenous or endogenous OGF and OGFr antagonists have been known to have a role in regulating cell viability and apoptosis. Moreover, the expression of proteins in the OGF - OGFr axis modulate differentiation and membrane expression of immune cells, which can enhance the immune response. In vivo and in vitro assays have shown that OGF and OGFr antagonists inhibit mitosis as well as induce apoptosis in gynecologic cancer cells. Although immune augmentation combination therapies can intensify cytotoxic activity, OGF or OGFr antagonists do not increase toxicities associated with dual-immune regulation. In conclusion, the OGF - OGFr axis provides significant strategies for antitumor efficiency in gynecological cancer.