Tumor-associated macrophages favor C26 murine colon carcinoma cell proliferation in an oxidative stress-dependent manner

Huang-qin decoction alleviates deoxycholic acid-induced colorectal cancer in mice by regulating gut microbiota

ETHNOPHARMACOLOGICAL RELEVANCE

Huangqin Decoction (HQD), a traditional Chinese medicine (TCM) formula documented in Shang Han Lun, has demonstrated safety and efficacy in the treatment of ulcerative colitis (UC). Recent studies also suggest that HQD exerts therapeutic effects on colorectal cancer (CRC). However, the underlying mechanisms remain unclear.

AIMS OF THE STUDY

This study aimed to investigate the therapeutic effects of HQD on CRC and explore its potential mechanisms of action.

METHODS

The active ingredients and potential targets of HQD were identified through network pharmacology-based analyses. The CRC-related targets were compared with those of HQD. Shared targets were subjected to Gene Ontology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, and a protein-protein interaction (PPI) network was constructed. Additionally, APCmin/+ mice were treated with 0.2 % deoxycholic acid (DCA) and gavaged with low or high doses of HQD. Tumor morphology was assessed using hematoxylin and eosin (HE) staining. Immunohistochemical staining was performed to evaluate the expression of Ki-67, Caspase-3, and MUC2 in the intestine. Periodic acid-Schiff (PAS) and PAS-alcian blue (PAS-AB) staining were utilized to detect mucin distribution and the number of goblet cells in the intestines of the mice. The mRNA expression levels of interleukin 6 (IL-6), mitogen-activated protein kinase 8 (MAPK8), vascular endothelial growth factor A (VEGFA), epidermal growth factor receptor (EGFR), albumin (ALB), and Caspase 3 (CASP3) were quantified using quantitative reverse-transcription PCR (qRT-PCR). Immunofluorescence was employed to assess the degree of apoptosis. Additionally, 16S ribosomal RNA gene sequencing, sequence curation and annotation, and metagenomic sequencing were performed to analyze changes in the composition of the mouse intestinal microbiota and related functions and signaling pathways.

RESULTS

The active ingredients of HQD were identified. GO and KEGG pathway enrichment analyses indicated that the shared targets were primarily involved in tumor suppression. HQD effectively treated DCA-induced CRC in mice. Furthermore, positive PAS and PAS-AB staining was significantly increased in the intestines of mice treated with HQD. HQD enhanced the abundance of Lachnospiraceae, Firmicutes, Fusobacteria, and Clostridium, while reducing the abundance of Eggerthellales. Additionally, HQD modulated secondary bile acid metabolism, carbohydrate synthesis, and other energy metabolism pathways, which may underlie its therapeutic effects.

CONCLUSION

HQD effectively treated CRC in mice, and its mechanisms of action may be related to the regulation of the gut microbiota.

Targeting tumor-associated macrophages in colon cancer: mechanisms and therapeutic strategies

Colon cancer (CC) remains a primary contributor to cancer-related fatalities worldwide, driven by difficulties in early diagnosis and constrained therapeutic options. Recent studies underscore the importance of the tumor microenvironment (TME), notably tumor-associated macrophages (TAMs), in fostering malignancy progression and therapy resistance. Through their inherent plasticity, TAMs facilitate immunosuppression, angiogenic processes, metastatic spread, and drug tolerance. In contrast to M1 macrophages, which promote inflammatory and tumoricidal responses, M2 macrophages support tumor expansion and dissemination by exerting immunosuppressive and pro-angiogenic influences. Consequently, manipulating TAMs has emerged as a potential avenue to enhance treatment effectiveness. This review outlines the origins, polarization states, and functions of TAMs in CC, highlights their role in driving tumor advancement, and surveys ongoing efforts to target these cells for better patient outcomes. Emerging therapeutic strategies aimed at modulating TAM functions - including depletion strategies, reprogramming approaches that shift M2-polarized TAMs toward an M1 phenotype, and inhibition of key signaling pathways sustaining TAM-mediated immunosuppression-are currently under active investigation. These approaches hold promise in overcoming TAM - induced resistance and improving immunotherapeutic efficacy in CC.

M2 macrophage-targeting peptide-modified liposomes enhance the uptake and antitumor efficacy of liposomal IFN-γ in mice with C26 colon carcinoma

While liposomes enhance the safety and pharmacokinetic profile of free drugs, they have not significantly improved therapeutic efficacy. To overcome this challenge, targeted depletion of tumor-associated macrophages (TAMs) shows significant potential as an effective antitumor therapy, reducing off-target effects in comparison to non-targeted liposomes. In the context of peptide-mediated targeted cancer therapy, we evaluated the reprogramming activity of IFN-γ liposomes on TAMs, as well as that of IFN-γ liposomes modified with an M2 macrophage-targeting peptide, which binds preferentially to murine anti-inflammatory M2 macrophages/M2-like TAMs. Flow cytometry analysis showed significantly enhanced cellular uptake of m2-peptide-targeted liposomes in J774.1 macrophage cell lines compared to non-targeted liposomes. In BALB/c mice bearing C-26 murine carcinoma, the m2-peptide-targeted liposome groups exhibited significantly higher IFN-γ concentrations compared to non-targeted counterparts within the tumor environment. Furthermore, m2-peptide-targeted F2 liposomes at doses of 25 μg IFN-γ/kg resulted in superior tumor growth inhibition and greater tumor accumulation, indicating the potential of macrophage-targeted therapy in cancer growth inhibition. However, they failed to improve the overall therapeutic efficacy compared to Doxil. This study proposes a combination therapy of m2-peptide-targeted IFN-γ liposomes with successful chemotherapeutic liposomes such as Doxil.

Targeting of M2 macrophages with IL-13-functionalized liposomal prednisolone inhibits melanoma angiogenesis in vivo

The intricate cooperation between cancer cells and nontumor stromal cells within melanoma microenvironment (MME) enables tumor progression and metastasis. We previously demonstrated that the interplay between tumor-associated macrophages (TAMs) and melanoma cells can be disrupted by using long-circulating liposomes (LCLs) encapsulating prednisolone phosphate (PLP) (LCL-PLP) that inhibited tumor angiogenesis coordinated by TAMs. In this study, our goal was to improve LCL specificity for protumor macrophages (M2-like (i.e., TAMs) macrophages) and to induce a more precise accumulation at tumor site by loading PLP into IL-13-conjugated liposomes (IL-13-LCL-PLP), since IL-13 receptor is overexpressed in this type of macrophages. The IL-13-LCL-PLP liposomal formulation was obtained by covalent attachment of thiolated IL-13 to maleimide-functionalized LCL-PLP. C57BL/6 mice bearing B16.F10 s.c melanoma tumors were used to investigate the antitumor action of LCL-PLP and IL-13-LCL-PLP. Our results showed that IL-13-LCL-PLP formulation remained stable in biological fluids after 24h and it was preferentially taken up by M2 polarized macrophages. IL-13-LCL-PLP induced strong tumor growth inhibition compared to nonfunctionalized LCL-PLP at the same dose, by altering TAMs-mediated angiogenesis and oxidative stress, limiting resistance to apoptosis and invasive features in MME. These findings suggest IL-13-LCL-PLP might become a promising delivery platform for chemotherapeutic agents in melanoma.

Immunosenescence in digestive system cancers: Mechanisms, research advances, and therapeutic strategies

Increasing lifespans and external environmental factors have contributed to the increase of age-related diseases, particularly cancer. A decrease in immune surveillance and clearance of cancer cells is the result of immunosenescence, which involves the remodeling of immune organs, the changes and functional decline of immune cell subsets, in association with systemic low-grade chronic inflammation. Stem cells aging in bone marrow and thymic involution are the most important causes of immunosenescence. Senescent cancer cells promote the differentiation, recruitment, and functional upregulation of immune-suppressive cell subsets e.g. regulatory T cells (Tregs), myeloid-derived suppressor cell (MDSC), tumor-associated macrophages (TAMS) through senescence-associated secretory phenotype (SASP) further exacerbating the immunosuppressive microenvironment. For digestive system cancers, age-related damage to the intestinal mucosal barrier, the aging of gut-associated lymphoid tissue (GALT), exposure to xenobiotic stimuli throughout life, and dysbiosis make the local immune microenvironment more vulnerable. This article systematically reviews the research progress of immunosenescence and immune microenvironment in digestive system cancers, as well as the exploration of related therapy strategies, hoping to point out new directions for research in the digestive system cancers.

Research progress of tumor-associated macrophages in immune checkpoint inhibitor tolerance in colorectal cancer

The relevant mechanism of tumor-associated macrophages (TAMs) in the treatment of colorectal cancer patients with immune checkpoint inhibitors (ICIs) is discussed, and the application prospects of TAMs in reversing the treatment tolerance of ICIs are discussed to provide a reference for related studies. As a class of drugs widely used in clinical tumor immunotherapy, ICIs can act on regulatory molecules on cells that play an inhibitory role-immune checkpoints-and kill tumors in the form of an immune response by activating a variety of immune cells in the immune system. The sensitivity of patients with different types of colorectal cancer to ICI treatment varies greatly. The phenotype and function of TAMs in the colorectal cancer microenvironment are closely related to the efficacy of ICIs. ICIs can regulate the phenotypic function of TAMs, and TAMs can also affect the tolerance of colorectal cancer to ICI therapy. TAMs play an important role in ICI resistance, and making full use of this target as a therapeutic strategy is expected to improve the immunotherapy efficacy and prognosis of patients with colorectal cancer.

Correlation of Immunomodulatory Cytokines with Tumor Volume and Cerebrospinal Fluid in Vestibular Schwannoma Patients

Sporadic vestibular schwannomas (VSs) often exhibit slow or negligible growth. Nevertheless, some VSs increase significantly in volume within a few months or grow continuously. Recent evidence indicates a role of inflammation in promoting VS growth. Therefore, our study aimed to identify cytokines, which are associated with larger VSs. The expression of different cytokines in VS tumor samples and VS primary cultures was investigated. Additionally, the concentration of cytokines in cell culture supernatants of VS primary cultures and cerebrospinal fluid (CSF) of VS patients and healthy controls were determined. Correlation analysis of cytokine levels with tumor volume, growth rate, Koos grade, age, and hearing was examined with Spearman's-rank test. The mRNA expression of CC-chemokine ligand (CCL) 18, growth differentiation factor (GDF) 15, and interferon regulatory factor 4 correlated positively with tumor volume. Moreover, the amount of GDF15 in the cell culture supernatant of primary cells correlated positively with tumor volume. The concentrations of the cytokines CCL2, CCL5, and CCL18 and transforming growth factor beta (TGFB) 1 in the CSF of the patients were significantly different from those in the CSF controls. Inhibition of immune cell infiltration could be a putative approach to prevent and control VS growth.

The effect of intestinal flora metabolites on macrophage polarization

Intestinal flora metabolites played a crucial role in immunomodulation by influencing host immune responses through various pathways. Macrophages, as a type of innate immune cell, were essential in chemotaxis, phagocytosis, inflammatory responses, and microbial elimination. Different macrophage phenotypes had distinct biological functions, regulated by diverse factors and mechanisms. Advances in intestinal flora sequencing and metabolomics have enhanced understanding of how intestinal flora metabolites affect macrophage phenotypes and functions. These metabolites had varying effects on macrophage polarization and different mechanisms of influence. This study summarized the impact of gut microbiota metabolites on macrophage phenotype and function, along with the underlying mechanisms associated with different metabolites produced by intestinal flora.

The role of tumor-associated macrophages in the radioresistance of esophageal cancer cells via regulation of the VEGF-mediated angiogenic pathway

Tumor-associated macrophages (TAMs) are known to promote tumor growth, invasion, metastasis, and protumor angiogenesis, but the role of TAMs in evading radiotherapy in esophagus cancer remains unclear. In this study, we first induced TAMs from human monocytes (THP-1) and identified using immunofluorescence and Western blotting assays. We then co-cultured them with human esophageal cancer cell lines. CCK-8, colony formation, Transwell, scratch test, and TUNEL assays showed that TAMs could promote proliferation, survival rate, invasion, migration, and radioresistance and could inhibit apoptosis of the esophageal squamous carcinoma cell lines KYSE-150 and TE-1 before and after radiotherapy both in vivo and in vitro. Using LV-VEGFA-RNAi lentiviral vectors, we also found that TAMs could increase the expression of VEGFA and that inhibition of VEGFA could inhibit the biological function caused by TAMs. Finally, a Western blotting assay was used to evaluate the expression of various factors underlying the mechanism of TAMs. VEGFA, MAPK, P-MAPK, BCL-2, and Snail proteins were found to be overexpressed in co-cultured groups, whereas after VEGFA inhibition, MAPK, P-MAPK, BCL-2, and Snail proteins were found to be significantly downregulated in the radiotherapy group. These study results offer important information regarding the mechanism of radioresistance in esophageal cancer.

Increased PKN2 and M2-Polarized Macrophages Promote HCT116 Cell Invasion

Colorectal cancer is the third most common malignant tumor, with highly invasive and metastatic potential in the later stage. This study investigated the role of PKN2 overexpression and M2-polarized macrophages in dictating the malignant phenotype of colorectal cancer cells. HCT116 colorectal cancer cell line with PKN2 overexpression was generated to investigate the functional role of PKN2. THP-1 cells were polarized into M2-like macrophages, and the co-culture system of THP-1/M2 cells and HCT116 cells was established to examine the impacts of M2-polairzed macrophages on the malignant phenotype of colorectal cancer cells. PKN2 overexpression promoted cell proliferation, migration and invasion in HCT116 colorectal cancer cells, and reduced spontaneous cell death in the cell culture. Besides, the presence of M2-polarized THP-1 cells significantly enhanced the aggressive phenotype of HCT116 cells. Both PKN2 overexpression and M2-polarized THP-1 cells increased the expression of NF-κB p65 in HCT116 cells, indicating that enhanced NF-κB signaling may contribute to the augmented aggressiveness of HCT116 cells. These findings suggest PKN2 as an oncogenic factor in colorectal cancer and that M2-polarized THP-1 cells may promote the progression of colorectal cancer by activating NF-κB signaling.

Redox Dysregulation in the Tumor Microenvironment Contributes to Cancer Metastasis

Significance: Redox dysregulation under pathological conditions results in excessive reactive oxygen species (ROS) accumulation, leading to oxidative stress and cellular oxidative damage. ROS function as a double-edged sword to modulate various types of cancer development and survival. Recent Advances: Emerging evidence has underlined that ROS impact the behavior of both cancer cells and tumor-associated stromal cells in the tumor microenvironment (TME), and these cells have developed complex systems to adapt to high ROS environments during cancer progression. Critical Issues: In this review, we integrated current progress regarding the impact of ROS on cancer cells and tumor-associated stromal cells in the TME and summarized how ROS production influences cancer cell behaviors. Then, we summarized the distinct effects of ROS during different stages of tumor metastasis. Finally, we discussed potential therapeutic strategies for modulating ROS for the treatment of cancer metastasis. Future Directions: Targeting the ROS regulation during cancer metastasis will provide important insights into the design of effective single or combinatorial cancer therapeutic strategies. Well-designed preclinical studies and clinical trials are urgently needed to understand the complex regulatory systems of ROS in the TME. Antioxid. Redox Signal. 39, 472-490.

Macrophage's role in solid tumors: two edges of a sword

The tumor microenvironment is overwhelmingly dictated by macrophages, intimately affiliated with tumors, exercising pivotal roles in multiple processes, including angiogenesis, extracellular matrix reconfiguration, cellular proliferation, metastasis, and immunosuppression. They further exhibit resilience to chemotherapy and immunotherapy via meticulous checkpoint blockades. When appropriately stimulated, macrophages can morph into a potent bidirectional component of the immune system, engulfing malignant cells and annihilating them with cytotoxic substances, thus rendering them intriguing candidates for therapeutic targets. As myelomonocytic cells relentlessly amass within tumor tissues, macrophages rise as prime contenders for cell therapy upon the development of chimeric antigen receptor effector cells. Given the significant incidence of macrophage infiltration correlated with an unfavorable prognosis and heightened resistance to chemotherapy in solid tumors, we delve into the intricate role of macrophages in cancer propagation and their promising potential in confronting four formidable cancer variants-namely, melanoma, colon, glioma, and breast cancers.

miR-141-3p accelerates ovarian cancer progression and promotes M2-like macrophage polarization by targeting the Keap1-Nrf2 pathway

The miR-141-3p has been reported to participate in regulating autophagy and tumor-stroma interactions in ovarian cancer (OC). We aim to investigate whether miR-141-3p accelerates the progression of OC and its effect on macrophage 2 polarization by targeting the Kelch-like ECH-associated protein1-Nuclear factor E2-related factor2 (Keap1-Nrf2) pathway. SKOV3 and A2780 cells were transfected with miR-141-3p inhibitor and negative control to confirm the regulation of miR-141-3p on OC development. Moreover, the growth of tumors in xenograft nude mice treated by cells transfected with miR-141-3p inhibitor was established to further testify the role of miR-141-3p in OC. The expression of miR-141-3p was higher in OC tissue compared with non-cancerous tissue. Downregulation of miR-141-3p inhibited the proliferation, migration, and invasion of ovarian cells. Furthermore, miR-141-3p inhibition also suppressed M2-like macrophage polarization and in vivo OC progression. Inhibition of miR-141-3p significantly enhanced the expression of Keap1, the target gene of miR-141-3p, and thus downregulated Nrf2, while activation of Nrf2 reversed the reduction in M2 polarization by miR-141-3p inhibitor. Collectively, miR-141-3p contributes to tumor progression, migration, and M2 polarization of OC by activating the Keap1-Nrf2 pathway. Inhibition of miR-141-3p attenuates the malignant biological behavior of ovarian cells by inactivating the Keap1-Nrf2 pathway.

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.

Wound Healing versus Metastasis: Role of Oxidative Stress

Many signaling pathways, molecular and cellular actors which are critical for wound healing have been implicated in cancer metastasis. These two conditions are a complex succession of cellular biological events and accurate regulation of these events is essential. Apart from inflammation, macrophages-released ROS arise as major regulators of these processes. But, whatever the pathology concerned, oxidative stress is a complicated phenomenon to control and requires a finely tuned balance over the different stages and responding cells. This review provides an overview of the pivotal role of oxidative stress in both wound healing and metastasis, encompassing the contribution of macrophages. Indeed, macrophages are major ROS producers but also appear as their targets since ROS interfere with their differentiation and function. Elucidating ROS functions in wound healing and metastatic spread may allow the development of innovative therapeutic strategies involving redox modulators.

Evaluating the role of IDO1 macrophages in immunotherapy using scRNA-seq and bulk-seq in colorectal cancer

Background

Macrophage infiltration is crucial for colorectal cancer (CRC) immunotherapy. Detailed classification of macrophage subsets will facilitate the selection of patients suitable for immunotherapy. However, the classification of macrophages in CRC is not currently detailed.

Methods

In this study, we combined single-cell RNA sequencing (scRNA-seq) and bulk-seq to analyze patients with colorectal cancer. scRNA-seq data were used to study cell-cell communication and to differentiate immune-infiltrating cells and macrophage subsets. Bulk-seq data were used to further analyze immune infiltration, clinical features, tumor mutational burden, and expression of immune checkpoint molecules in patients with CRC having different macrophage subsets.

Results

Seven macrophage subpopulations were identified, among which indoleamine 2,3 dioxygenase 1 (IDO1) macrophages had the most significant difference in the degree of infiltration among normal, microsatellite-unstable, and microsatellite-stable populations. We then performed gene set variation analysis using 12 marker genes of IDO1 macrophages and divided the patients into two clusters: high-IDO1 macrophages (H-IDO1M) and low-IDO1 macrophages (L-IDO1M). H-IDO1M showed higher infiltration of immune cells, higher expression of immune checkpoints, and less advanced pathological stages than L-IDO1M (p < 0.05).

Conclusions

This study elucidated that IDO1-macrophage-based molecular subtypes can predict the response to immunotherapy in patients with CRC. The results provide new insights into tumor immunity and help in clinical decisions regarding designing effective immunotherapy for these patients.

EV-Mediated Chemoresistance in the Tumor Microenvironment: Is NF-κB a Player?

Drug resistance is a major impediment to patient survival and remains the primary cause of unsuccessful cancer therapy. Drug resistance occurs in many tumors and is frequently induced by chemotherapy which triggers a defensive response both in cancerous and cancer-associated cells that constitute the tumor microenvironment (TME). Cell to cell communication within the TME is often mediated by extracellular vesicles (EVs) which carry specific tumor-promoting factors able to activate survival pathways and immune escape mechanisms, thus sustaining tumor progression and therapy resistance. NF-κB has been recognized as a crucial player in this context. NF-κB activation is involved in EVs release and EVs, in turn, can trigger NF-κB pathway activation in specific contexts, based on secreting cytotype and their specific delivered cargo. In this review, we discuss the role of NF-κB/EVs interplay that sustain chemoresistance in the TME by focusing on the molecular mechanisms that underlie inflammation, EVs release, and acquired drug resistance.

Cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs); where do they stand in tumorigenesis and how they can change the face of cancer therapy?

The tumor microenvironment (TME) and its components have recently attracted tremendous attention in cancer treatment strategies, as alongside the genetic and epigenetic alterations in tumor cells, TME could also provide a fertile background for malignant cells to survive and proliferate. Interestingly, TME plays a vital role in the mediation of cancer metastasis and drug resistance even against immunotherapeutic agents. Among different cells that are presenting in TME, tumor-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs) have shown to have significant value in the regulation of angiogenesis, tumor metastasis, and drug-resistance through manipulating the composition as well as the organization of extracellular matrix (ECM). Evidence has shown that the presence of both TAMs and CAFs in TME is associated with poor prognosis and failure of chemotherapeutic agents. It seems that these cells together with ECM form a shield around tumor cells to protect them from the toxic agents and even the adaptive arm of the immune system, which is responsible for tumor surveillance. Given this, targeting TAMs and CAFs seems to be an essential approach to potentiate the cytotoxic effects of anti-cancer agents, either conventional chemotherapeutic drugs or immunotherapies. In the present review, we aimed to take a deep look at the mechanobiology of CAFs and TAMs in tumor progression and to discuss the available therapeutic approaches for harnessing these cells in TME.

Active Tumor-Targeting Nano-formulations Containing Simvastatin and Doxorubicin Inhibit Melanoma Growth and Angiogenesis

Primary melanoma aggressiveness is determined by rapid selection and growth of cellular clones resistant to conventional treatments, resulting in metastasis and recurrence. In addition, a reprogrammed tumor-immune microenvironment supports melanoma progression and response to therapy. There is an urgent need to develop selective and specific drug delivery strategies for modulating the interaction between cancer cells and immune cells within the tumor microenvironment. This study proposes a novel combination therapy consisting of sequential administration of simvastatin incorporated in IL-13-functionalized long-circulating liposomes (IL-13-LCL-SIM) and doxorubicin encapsulated into PEG-coated extracellular vesicles (PEG-EV-DOX) to selectively target both tumor-associated macrophages and melanoma cells. To this end, IL-13 was conjugated to LCL-SIM which was obtained via the lipid film hydration method. EVs enriched from melanoma cells were passively loaded with doxorubicin. The cellular uptake of rhodamine-tagged nano-particles and the antiproliferative potential of the treatments by using the ELISA BrdU-colorimetric immunoassay were investigated in vitro. Subsequently, the therapeutic agents were administered i.v in B16.F10 melanoma-bearing mice, and tumor size was monitored during treatment. The molecular mechanisms of antitumor activity were investigated using angiogenic and inflammatory protein arrays and western blot analysis of invasion (HIF-1) and apoptosis markers (Bcl-xL and Bax). Quantification of oxidative stress marker malondialdehyde (MDA) was determined by HPLC. Immunohistochemical staining of angiogenic markers CD31 and VEGF and of pan-macrophage marker F4/80 was performed to validate our findings. The in vitro data showed that IL-13-functionalized LCL were preferentially taken up by tumor-associated macrophages and indicated that sequential administration of IL-13-LCL-SIM and PEG-EV-DOX had the strongest antiproliferative effect on tumor cells co-cultured with tumor-associated macrophages (TAMs). Accordingly, strong inhibition of tumor growth in the group treated with the sequential combination therapy was reported in vivo. Our data suggested that the antitumor action of the combined treatment was exerted through strong inhibition of several pro-angiogenic factors (VEGF, bFGF, and CD31) and oxidative stress-induced upregulation of pro-apoptotic protein Bax. This novel drug delivery strategy based on combined active targeting of both cancer cells and immune cells was able to induce a potent antitumor effect by disruption of the reciprocal interactions between TAMs and melanoma cells.

Therapeutic Approaches Targeting Proteins in Tumor-Associated Macrophages and Their Applications in Cancers

Tumor-associated macrophages (TAMs) promote tumor proliferation, invasion, angiogenesis, stemness, therapeutic resistance, and immune tolerance in a protein-dependent manner. Therefore, the traditional target paradigms are often insufficient to exterminate tumor cells. These pro-tumoral functions are mediated by the subsets of macrophages that exhibit canonical protein markers, while simultaneously having unique transcriptional features, which makes the proteins expressed on TAMs promising targets during anti-tumor therapy. Herein, TAM-associated protein-dependent target strategies were developed with the aim of either reducing the numbers of TAMs or inhibiting the pro-tumoral functions of TAMs. Furthermore, the recent advances in TAMs associated with tumor metabolism and immunity were extensively exploited to repolarize these TAMs to become anti-tumor elements and reverse the immunosuppressive tumor microenvironment. In this review, we systematically summarize these current studies to fully illustrate the TAM-associated protein targets and their inhibitors, and we highlight the potential clinical applications of targeting the crosstalk among TAMs, tumor cells, and immune cells in anti-tumor therapy.

Inhibition of BCL9 Modulates the Cellular Landscape of Tumor-Associated Macrophages in the Tumor Immune Microenvironment of Colorectal Cancer

Tumor-associated macrophages (TAMs) are an indispensable part of the tumor microenvironment (TME), and they likely play a negative rather than positive role in cancer treatment. However, the cellular landscape and transcriptional profile regulation of TAMs in the case of tumor gene inactivation or chemical interference remains unclear. The B-cell lymphoma 9/B-cell lymphoma 9-like (BCL9/BCL9L) is a critical transcription co-factor of β-catenin. Suppression of Bcl9 inhibits tumor growth in mouse models of colorectal cancer (CRC). Here, we studied the TAMs of CRC by single-cell sequencing. Bcl9 depletion caused macrophage polarization inhibition from M0 to M2 and changed the CRC TME, which further interferes with the inflammation of M0 and M1. The transcription factor regulating these processes may be related to the Wnt signaling pathway from multiple levels. Furthermore, we also found that the cells delineated from monocyte to NK-like non-functioning cells were significantly different in the BCL9-deprived population. Combining these data, we proposed a TAM-to-NK score to evaluate the dynamic balance in TME of monocyte/TAM cells and NK-like non-functioning cells in The Cancer Genome Atlas (TCGA) clinical samples to verify the clinical significance. We demonstrated that the cell type balance and transcription differences of TAMs regulated by BCL9-driven Wnt signaling affected immune surveillance and inflammation of cancer, ultimately affecting patients' prognosis. We thereby highlighted the potential of targeting Wnt signaling pathway through cancer immunotherapy.

A Screening Study for the Development of Simvastatin-Doxorubicin Liposomes, a Co-Formulation with Future Perspectives in Colon Cancer Therapy

An increasing number of studies published so far have evidenced the benefits of Simvastatin (SIM) and Doxorubicin (DOX) co-treatment in colorectal cancer. In view of this, the current study aimed to investigate the pharmaceutical development of liposomes co-encapsulating SIM and DOX, by implementing the Quality by Design (QbD) concept, as a means to enhance the antiproliferative effect of the co-formulation on C26 murine colon cancer cells co-cultured with macrophages. It is known that the quality profile of liposomes is dependent on the critical quality attributes (CQAs) of liposomes (drug entrapped concentration, encapsulation efficiency, size, zeta potential, and drug release profile), which are, in turn, directly influenced by various formulation factors and processing parameters. By using the design of experiments, it was possible to outline the increased variability of CQAs in relation to formulation factors and identify by means of statistical analysis the material attributes that are critical (phospholipids, DOX and SIM concentration) for the quality of the co-formulation. The in vitro studies performed on a murine colon cancer cell line highlighted the importance of delivering the optimal drug ratio at the target site, since the balance antiproliferative vs. pro-proliferative effects can easily be shifted when the molar ratio between DOX and SIM changes.

Tumor-Associated Macrophages (TAMs) in Colorectal Cancer (CRC): From Mechanism to Therapy and Prognosis

Colorectal cancer (CRC) is a malignant tumor in the digestive system whose incidence and mortality is high-ranking among tumors worldwide. The initiation and progression of CRC is a complex process involving genetic alterations in cancer cells and multiple factors from the surrounding tumor cell microenvironment. As accumulating evidence has shown, tumor-associated macrophages (TAMs)—as abundant and active infiltrated inflammatory cells in the tumor microenvironment (TME)—play a crucial role in CRC. This review focuses on the different mechanisms of TAM in CRC, including switching of phenotypical subtypes; promoting tumor proliferation, invasion, and migration; facilitating angiogenesis; mediating immunosuppression; regulating metabolism; and interacting with the microbiota. Although controversy remains in clinical evidence regarding the role of TAMs in CRC, clarifying their significance in therapy and the prognosis of CRC may shed new light on the optimization of TAM-centered approaches in clinical care.

Lymphocyte-to-monocyte ratio predicts survival after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

Aim: Lymphocyte-to-monocyte ratio (LMR) predicts overall survival (OS) in patients with colorectal cancer. We explored LMR in patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). Materials & methods: We identified all patients undergoing CRS/HIPEC for colorectal or appendiceal adenocarcinoma at our institution. We analyzed LMR's relationship with clinicopathologic variables with Kaplan-Meier log-rank survival analyses and multivariable Cox regression models with 5-year OS. Results: Two hundred and sixteen patients underwent CRS/HIPEC. Five-year OS for low LMR (≤3.71) was 35.2 versus 60.4% for elevated LMR (hazard ratio [HR]: 2.0; 95% CI: 1.1-3.5; p = 0.02). On multivariable Cox-regression, elevated LMR was significantly associated with OS (p ≤ 0.05). Conclusion: LMR is an independent predictor of OS in patients undergoing CRS/HIPEC for colorectal and appendiceal adenocarcinoma.

Exosomal miR-183-5p Shuttled by M2 Polarized Tumor-Associated Macrophage Promotes the Development of Colon Cancer via Targeting THEM4 Mediated PI3K/AKT and NF-κB Pathways

Background

Abnormal accumulation of macrophages in the colon cancer (CC) contribute to its progression. miR-183-5p has been confirmed as an oncogene in CC and this article explores the effect and mechanism of exosomal miR-183-5p enriched by M2-polarized tumor-associated macrophages (TAM) on CC cells.

Methods

The human macrophage THP1 was induced to M2 polarization through IL-4 and IL-13 treatment. Exosomes in THP1 were isolated through ultracentrifugation, and the miR-183-5p expression in macrophages and exosomes was verified by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The miR-183-5p inhibitors and mimics were applied to down-regulate and upregulate miR-183-5p in macrophages, respectively. Meanwhile, CC cell lines LoVo and SW480 were treated with the macrophage conditioned medium and exosomes, respectively. CC cells’ proliferation, invasion, and apoptosis were tested by the cell counting kit-8 (CCK-8) assay, colony formation assay, flow cytometry (FCM), Transwell assay, and xenograft assay, respectively. The profiles of thioesterase superfamily member 4 (THEM4), Akt, and NF-κB were compared by Western blotting (WB).

Results

The miR-183-5p level in M2-TAM and M2-TAM-derived exosomes was significantly increased. Meanwhile, M2-TAM and M2-TAM-derived exosomes significantly facilitated CC cell proliferation and invasion and dampened apoptosis. Overexpression of miR-183-5p in M2-TAM aggravated M2-TAM-mediated promotive effects on CC cells, with down-regulating miR-183-5p reversed M2-TAM-mediated tumor-promotive effects. Mechanically, miR-183-5p targeted THEM4 and inhibited its mRNA and protein expression. Overexpressing THEM4 abated miR-183-5p-mediated carcinogenic effects and inactivates Akt and NF-κB pathways in CC cells. Overall, this article elaborated that exosomal miR-183-5p shuttled by M2-TAM mediated Akt/NF-κB pathway to accelerate CC progression through targeting THEM4.

Tumor-associated macrophages: role in tumorigenesis and immunotherapy implications

Tumor-associated macrophages (TAMs) occupy an important position in the tumor microenvironment (TME), they are a highly plastic heterogeneous population with complex effects on tumorigenesis and development. TAMs secrete a variety of cytokines, chemokines, and proteases, which promote the remodeling of extracellular matrix, tumor cell growth and metastasis, tumor vessel and lymphangiogenesis, and immunosuppression. TAMs with different phenotypes have different effects on tumor proliferation and metastasis. TAMs act a pivotal part in occurrence and development of tumors, and are very attractive target to inhibit tumor growth and metastasis in tumor immunotherapy. This article reviews the interrelationship between TAMs and tumor microenvironment and its related applications in tumor therapy.

Roles of Reactive Oxygen Species in Biological Behaviors of Prostate Cancer

Prostate cancer (PCa), known as a heterogenous disease, has a high incidence and mortality rate around the world and seriously threatens public health. As an inevitable by-product of cellular metabolism, reactive oxygen species (ROS) exhibit beneficial effects by regulating signaling cascades and homeostasis. More and more evidence highlights that PCa is closely associated with age, and high levels of ROS are driven through activation of several signaling pathways with age, which facilitate the initiation, development, and progression of PCa. Nevertheless, excessive amounts of ROS result in harmful effects, such as genotoxicity and cell death. On the other hand, PCa cells adaptively upregulate antioxidant genes to detoxify from ROS, suggesting that a subtle balance of intracellular ROS levels is required for cancer cell functions. The current review discusses the generation and biological roles of ROS in PCa and provides new strategies based on the regulation of ROS for the treatment of PCa.

Caffeine and its main targets of colorectal cancer

Caffeine is a purine alkaloid and is widely consumed in coffee, soda, tea, chocolate and energy drinks. To date, a growing number of studies have indicated that caffeine is associated with many diseases including colorectal cancer. Caffeine exerts its biological activity through binding to adenosine receptors, inhibiting phosphodiesterases, sensitizing calcium channels, antagonizing gamma-aminobutyric acid receptors and stimulating adrenal hormones. Some studies have indicated that caffeine can interact with signaling pathways such as transforming growth factor β, phosphoinositide-3-kinase/AKT/mammalian target of rapamycin and mitogen-activated protein kinase pathways through which caffeine can play an important role in colorectal cancer pathogenesis, metastasis and prognosis. Moreover, caffeine can act as a general antioxidant that protects cells from oxidative stress and also as a regulatory factor of the cell cycle that modulates the DNA repair system. Additionally, as for intestinal homeostasis, through the interaction with receptors and cytokines, caffeine can modulate the immune system mediating its effects on T lymphocytes, B lymphocytes, natural killer cells and macrophages. Furthermore, caffeine can not only directly inhibit species in the gut microbiome, such as Escherichia coli and Candida albicans but also can indirectly exert inhibition by increasing the effects of other antimicrobial drugs. This review summarizes the association between colorectal cancer and caffeine that is being currently studied.

Liposomal simvastatin sensitizes C26 murine colon carcinoma to the antitumor effects of liposomal 5-fluorouracil in vivo

5-Fluorouracil-based therapy remains the main approach in colorectal cancer, even though there are still some drawbacks, such as chemoresistance. In this study we combined 5-fluorouracil encapsulated in long-circulating liposomes with simvastatin, also encapsulated in long-circulating liposomes, that was previously proved to exert antitumor actions on the same tumor model. The production of angiogenic/inflammatory proteins was assessed by protein array and the production of markers for tumor aggressiveness (Bcl-2, Bax, and nuclear factor [NF]-κB) were determined by western blot analysis. Intratumor oxidative stress was evaluated through measurement of malondialdehyde level by HPLC, and through spectrophotometric analysis of catalytic activity of catalase and of total antioxidant capacity. Immunohistochemical analysis of tumors for CD31 expression was assessed. Intratumor activity of MMP-2 by gelatin zymography was also carried out. Our results revealed that combined therapies based on liposomal formulations exerted enhanced antitumor activities compared with combined treatment with free drugs. Sequential treatment with liposomal simvastatin and liposomal 5-fluorouracil showed the strongest antitumor activity in C26 colon carcinoma in vivo, mainly through inhibition of tumor angiogenesis. Important markers for cancer progression (Bcl-2, Bax, NF-κB, and intratumor antioxidants) showed that liposomal simvastatin might sensitize C26 cells to liposomal 5-fluorouracil treatment in both regimens tested. The outcome of simultaneous treatment with liposomal formulations was superior to sequential treatment with both liposomal types as the invasive capacity of C26 tumors was strongly increased after the latest treatment. The antitumor efficacy of combined therapy in C26 colon carcinoma might be linked to the restorative effects on proteins balance involved in tumor angiogenesis.

Biologically Active Ajuga Species Extracts Modulate Supportive Processes for Cancer Cell Development

Backround:Ajuga species have been used in traditional medicine for their diuretic, anti-inflammatory, wound-healing, and hepatoprotective properties.

Purpose: The phytochemical profile and anticancer potential of three Ajuga sp. (A. genevensis, A. chamaepitys, and A. laxmannii) from Romania was investigated.

Materials and Methods: The phytochemicals were extracted from the aerial parts of Ajuga sp. by using different solvents and methods. The hydroalcoholic extracts were examined for total phenolic, flavonoid and iridoid contents, and HPLC/MS was used to analyze the polyphenolic compounds and iridoids. The phytochemical profile was also evaluated by principal component analysis in connection with antitumor efficacy of extracts. The antiproliferative potential was evaluated using the ELISA BrdU-colorimetric immunoassay. Western Blot with regard to inflammatory protein NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) p65 subunit expression in cell lysates was performed. Quantification of oxidative stress marker malondialdehyde (MDA) was determined by high-performance liquid chromatography (HPLC). Enzymatic and non-enzymatic antioxidant capability was assessed by measuring catalase activity and by evaluating the total antioxidant capacity (TAC) of treated cells.

Results:Ajuga laxmannii ethanol extract showed the highest total phenolic and flavonoid content, while A. genevensis ethanol extract was more abundant in iridoids. The overall cytostatic effect of the investigated plant extracts was exerted through strong inhibitory actions on NF-κB, the key molecule involved in the inflammatory response and via oxidative stress modulatory effects in both murine colon carcinoma and melanoma cell lines.

Conclusion:Ajuga laxmannii showed the most significant antitumor activity and represents an important source of bioactive compounds, possibly an additional form of treatment alongside conventional anticancer drugs.

PMA treated THP-1-derived-IL-6 promotes EMT of SW48 through STAT3/ERK-dependent activation of Wnt/β-catenin signaling pathway

Colon cancer is one of the most common digestive malignant tumors that leads to high mortality worldwide, and metastasis is the primary cause of cancer-related death. It is well accepted that the epithelial-mesenchymal transition (EMT) plays a key role in the process of metastasis. As a cytokine that macrophage secretes, IL-6 is involved in the progression of tumors, including the invasion and metastasis via kinds of signaling pathways. However, the mechanism of interactions between IL-6, macrophage, EMT and colon cancer is not fully understood. Increased CD68⁺ macrophages and IL-6 level were found in colon tumor as compared to normal colon tissue. Metastatic lymph node showed even more CD68⁺ macrophages and higher IL-6 level than the primary tumor. These results suggested that macrophages and IL-6 play an important role in EMT of colon cancer. In order to investigate the effect of macrophage and IL-6 on EMT of colon cancer, we cultured human colon carcinoma cell line SW48 with conditioned medium (CM) from PMA-stimulated monocyte THP-1 cells and tested for IL-6 dependent EMT pathways. Wound healing assay and Transwell assay were used to analyze cell migration and invasion. Results showed that CM-treated SW48 cells increased IL-6 production and displayed elevated capacity of migration and invasion compared to untreated cells. Increased expressions of EMT markers (N-cadherin, Vimentin and β-catenin) and decreased expression of EMT marker(E-cadherin) were found in CM-treated SW48 cells by Western Blot. The addition of an anti-IL-6 antibody significantly inhibited the increase of EMT markers (Vimentin and β-catenin) as well as cell migration and invasion, suggesting that IL-6 played a critical role in promoting EMT of CM-treated SW48 cells. In addition, we found that the levels of p-STAT3 and p-ERK increased in CM-treated SW48 compared to untreated cells, which can be reversed by AG490, an inhibitor of JAK. In the meantime, the suppression of JAK-associated signaling pathways caused a decrease of β-catenin. In summary, our study suggested that macrophage-induced IL-6 promotes migration and invasion of colon cancer cell via Wnt/β-catenin pathway in STAT3/ERK-dependent way.

Combination therapy of simvastatin and 5, 6-dimethylxanthenone-4-acetic acid synergistically suppresses the aggressiveness of B16.F10 melanoma cells

The major drawback of current anti-angiogenic therapies is drug resistance, mainly caused by overexpression of the transcription factor, hypoxia-inducible factor 1α (HIF-1α) as a result of treatment-induced hypoxia, which stimulates cancer cells to develop aggressive and immunosuppressive phenotypes. Moreover, the cancer cell resistance to anti-angiogenic therapies is deeply mediated by the communication between tumor cells and tumor-associated macrophages (TAMs)-the most important microenvironmental cells for the coordination of all supportive processes in tumor development. Thus, simultaneous targeting of TAMs and cancer cells could improve the outcome of the anti-angiogenic therapies. Since our previous studies proved that simvastatin (SIM) exerts strong antiproliferative actions on B16.F10 murine melanoma cells via reduction of TAMs-mediated oxidative stress and inhibition of intratumor production of HIF-1α, we investigated whether the antitumor efficacy of the anti-angiogenic agent-5,6-dimethylxanthenone-4-acetic acid (DMXAA) could be improved by its co-administration with the lipophilic statin. Our results provide confirmatory evidence for the ability of the combined treatment to suppress the aggressive phenotype of the B16.F10 melanoma cells co-cultured with TAMs under hypoxia-mimicking conditions in vitro. Thus, proliferation and migration capacity of the melanoma cells were strongly decelerated after the co-administration of SIM and DMXAA. Moreover, our data suggested that the anti-oxidant action of the combined treatment, as a result of melanogenesis stimulation, might be the principal cause for the simultaneous suppression of key molecules involved in melanoma cell aggressiveness, present in melanoma cells (HIF-1α) as well as in TAMs (arginase-1). Finally, the concomitant suppression of these proteins might have contributed to a very strong inhibition of the angiogenic capacity of the cell co-culture microenvironment.

Redox control of cancer cell destruction

Redox regulation has been proposed to control various aspects of carcinogenesis, cancer cell growth, metabolism, migration, invasion, metastasis and cancer vascularization. As cancer has many faces, the role of redox control in different cancers and in the numerous cancer-related processes often point in different directions. In this review, we focus on the redox control mechanisms of tumor cell destruction. The review covers the tumor-intrinsic role of oxidants derived from the reduction of oxygen and nitrogen in the control of tumor cell proliferation as well as the roles of oxidants and antioxidant systems in cancer cell death caused by traditional anticancer weapons (chemotherapeutic agents, radiotherapy, photodynamic therapy). Emphasis is also put on the role of oxidants and redox status in the outcome following interactions between cancer cells, cytotoxic lymphocytes and tumor infiltrating macrophages.

In Vivo Double Targeting of C26 Colon Carcinoma Cells and Microenvironmental Protumor Processes Using Liposomal Simvastatin

Purpose: Besides cholesterol lowering effects, simvastatin (SIM) at very high doses possesses antitumor actions. Moreover our previous studies demonstrated that tumor-targeted delivery of SIM by using long-circulating liposomes (LCL) improved the therapeutic index of this drug in murine melanoma-bearing mice. To evaluate whether this finding can be exploited for future therapy of colorectal cancer the antitumor activity and the underlying mechanisms of long-circulating liposomal simvastatin (LCL-SIM) efficacy for inhibition of C26 murine colon carcinoma growth in vivo were investigated.

Materials and Methods: To find LCL-SIM dose with the highest therapeutic index, dose-response relationship and side effects of different LCL-SIM doses were assessed in C26 colon carcinoma-bearing mice. The underlying mechanisms of LCL-SIM versus free SIM treatments were investigated with regard to their actions on C26 cell proliferation and apoptosis (via tumor tissues immunostaining for PCNA and Bax markers), tumor inflammation (via western blot analysis of NF-κΒ production), angiogenesis (using an angiogenic protein array), and oxidative stress (by HPLC assessment of malondialdehyde).

Results: Our findings suggest that LCL-SIM antitumor activity on C26 colon carcinoma is a result of the tumor-targeting property of the liposome formulation, as free SIM treatment was ineffective. Moreover, LCL-SIM exerted significant antiproliferative and pro-apoptotic actions on C26 cells, notable suppressive effects on two main supportive processes for tumor development, inflammation and angiogenesis, and only slight anti-oxidant actions.

Conclusion: Our data proved that LCL-SIM antitumor activity in C26 colon carcinoma was based on cytotoxic effects on these cancer cells and suppressive actions on tumor angiogenesis and inflammation.

Liposomal prednisolone phosphate potentiates the antitumor activity of liposomal 5-fluorouracil in C26 murine colon carcinoma in vivo

The antitumor efficacy of 5-fluorouracil (5-FU) in advanced colorectal cancer (CRC) is hindered not only by the low therapeutic index, but also by tumor cell resistance to this cytotoxic drug. Therefore, to enhance the 5-FU antitumor activity, the present research used a novel tumor-targeted therapy based on the co-administration of 5-FU encapsulated in long-circulating liposomes (LCL-5-FU) together with liposomal prednisolone phosphate (LCL-PLP), a formulation with known anti-angiogenic actions on C26 murine colon carcinoma cells. Thus, we assessed the in vivo effects of the combined liposomal drug therapy on C26 carcinoma growth as well as on the production of molecular markers with key roles in tumor development such as angiogenic, inflammatory, and oxidative stress molecules. To get further insight into the polarization state of tumor microenvironment after the treatment, we determined the IL-10/IL-12p70 ratio in tumors. Our results showed that combined liposomal drug therapy inhibited almost totally tumor growth and was superior as antitumor activity to both single liposomal drug therapies tested. The antitumor efficacy of the combined therapy was mainly related to the anti-angiogenic and anti-inflammatory actions on C26 carcinoma milieu, being favored by its controlling effect on intratumor oxidative stress and the skewing of polarization of tumor microenvironmental cells toward their antineoplastic phenotypes. Thus, our study unveils a promising treatment strategy for CRC that should be furthermore considered.