Autophagy suppresses isoprenaline-induced M2 macrophage polarization via the ROS/ERK and mTOR signaling pathway

Serum Starvation Regulates Autophagy of Human Periodontal Ligament Cells Through Reactive Oxygen Species Mediated Adenosine Monophosphate-Activated Protein Kinase/Mechanistic Target of RAPAMYCIN Axis

INTRODUCTION AND AIMS

Human periodontal ligament cells (hPDLCs) play a pivotal role in periodontal tissue remodelling, a process essential for orthodontic tooth movement (OTM). Autophagy, a survival mechanism under cellular stress, is induced by nutrient deprivation and impacts hPDLC function. This study aimed to explore the role of autophagy in the adaptive response of hPDLCs to nutritional stress, an environment simulating conditions during OTM.

METHODS

Nutrient deprivation in hPDLCs was modelled through serum starvation. Autophagy levels and relevant markers were assessed using electron microscopy, protein assays, and gene expression analyses. Emphasis was placed on adenosine monophosphate-activated protein kinase (AMPK) signalling, specifically phosphorylation of AMPKα at Thr172, as a regulatory node in autophagy induction. Loss- and gain-of-function approaches were utilized to investigate the role of Thr172 in AMPK-mediated autophagy under nutrient stress.

RESULTS

Findings indicated a marked increase in reactive oxygen species-mediated autophagy in hPDLCs under nutrient deprivation. This process was significantly regulated by AMPK activation through Thr172 phosphorylation, establishing AMPK as a critical factor in autophagy induction during cellular adaptation to nutritional stress.

CONCLUSION

Nutritional stress enhances reactive oxygen species-mediated autophagy in hPDLCs via AMPK signalling, underscoring the role of autophagy in cellular adaptation during OTM. Targeting the AMPK pathway could provide novel insights for optimizing orthodontic treatment by leveraging cellular adaptive mechanisms.

CLINICAL RELEVANCE

Understanding the molecular mechanisms underlying autophagy in hPDLCs opens potential therapeutic pathways to improve OTM outcomes. Modulating autophagy may lead to advances in orthodontic therapies that facilitate periodontal tissue remodelling, enhancing clinical effectiveness.

TGF-β1 induces autophagy and mediates the effect on macrophages differentiation in primary liver cancer

BACKGROUND

Tumor-associated macrophages (TAMs) are closely associated with tumor development and patient outcomes due to their plasticity and polarization capacity. Several distinct TAMs have been proposed, but a complete understanding of heterogeneity and differentiation spectrum of macrophage in human primary liver cancer remains elusive.

METHODS

Deep single-cell RNA sequencing (scRNA-seq) data from 19 primary liver cancer patients were used to profile the transcriptomes of TAMs in liver cancer. Ingenuity pathway analysis (IPA) and in vitro experiments were used to explore possible mechanisms responsible for related signaling pathways altered at the transcriptional level. Finally, we analyzed the relationship between the abundance of the TAMs and the survival outcomes of the 428 patients in the Cancer Genome Atlas (TCGA).

RESULTS

Transcriptional profiles allowed us to identify four distinct TAMs cell subsets based on molecular and functional properties and to reconstruct their developmental trajectory. Specifically, TAM_c4 was preferentially enriched and potentially expanded in the advanced-stage patients or those receiving immune checkpoint blockade therapy (ICT). Gene pathway analysis revealed aberrant TGFB1 activation in TAM_c4, which was experimentally confirmed to drive TAM phenotypic transitions via autophagy signaling. High abundance of TAM_c4 is found to be related to a short survival time and low abundance of CD8+ T cells in primary liver cancers.

CONCLUSIONS

This integrated transcriptome compendium and experimental validation offer both mechanistic insights and a resource for understanding TAM heterogeneity in primary liver cancers.

Anti-IL-17 Inhibits PINK1/Parkin Autophagy and M1 Macrophage Polarization in Rheumatic Heart Disease

Rheumatic heart disease (RHD) is an important and preventable cause of cardiovascular death and disability, but the lack of clarity about its exact mechanisms makes it more difficult to find alternative methods or prevention and treatment. We previously demonstrated that increased IL-17 expression plays a crucial role in the development of RHD-related valvular inflammatory injury. Macrophage autophagy/polarization may be a pro-survival strategy in the initiation and resolution of the inflammatory process. This study investigated the mechanism by which IL-17 regulates autophagy/polarization activation in macrophages. A RHD rat model was generated, and the effects of anti-IL-17 and 3-methyladenine (3-MA) were analyzed. The molecular mechanisms underlying IL-17-induced macrophage autophagy/polarization were investigated via in vitro experiments. In our established RHD rat model, the activation of the macrophage PINK1/Parkin autophagic pathway in valve tissue was accompanied by M1 macrophage infiltration, and anti-IL-17 treatment inhibited autophagy and reversed macrophage inflammatory infiltration, thereby attenuating endothelial-mesenchymal transition (EndMT) in the valve tissue. The efficacy of 3-MA treatment was similar to that of anti-IL-17 treatment. Furthermore, in THP-1 cells, the pharmacological promotion of autophagy by IL-17 induced M1-type polarization, whereas the inhibition of autophagy by 3-MA reversed this process. Mechanistically, silencing PINK1 in THP-1 blocked autophagic flux. Moreover, IL-17-induced M1-polarized macrophages promoted EndMT in HUVECs. This study revealed that IL-17 plays an important role in EndMT in RHD via the PINK1/Parkin autophagic pathway and macrophage polarization, providing a potential therapeutic target.

Synergistic Activation of LEPR and ADRB2 Induced by Leptin Enhances Reactive Oxygen Specie Generation in Triple-Negative Breast Cancer Cells

PURPOSE

Leptin interacts not only with leptin receptor (LEPR) but also engages with other receptors. While the pro-oncogenic effects of the adrenergic receptor β2 (ADRB2) are well-established, the role of leptin in activating ADRB2 in triple-negative breast cancer (TNBC) remains unclear.

MATERIALS AND METHODS

The pro-carcinogenic effects of LEPR were investigated using murine TNBC cell lines, 4T1 and EMT6, and a tumor-bearing mouse model. Expression levels of LEPR, NADPH oxidase 4 (NOX4), and ADRB2 in TNBC cells and tumor tissues were analyzed via western blot and quantitative real-time polymerase chain reaction. Changes in reactive oxygen species (ROS) levels were assessed using flow cytometry and MitoSox staining, while immunofluorescence double-staining confirmed the co-localization of LEPR and ADRB2.

RESULTS

LEPR activation promoted NOX4-derived ROS and mitochondrial ROS production, facilitating TNBC cell proliferation and migration, effects which were mitigated by the LEPR inhibitor Allo-aca. Co-expression of LEPR and ADRB2 was observed on cell membranes, and bioinformatics data revealed a positive correlation between the two receptors. Leptin activated both LEPR and ADRB2, enhancing intracellular ROS generation and promoting tumor progression, which was effectively countered by a specific ADRB2 inhibitor ICI118551. In vivo, leptin injection accelerated tumor growth and lung metastases without affecting appetite, while treatments with Allo-aca or ICI118551 mitigated these effects.

CONCLUSION

This study demonstrates that leptin stimulates the growth and metastasis of TNBC through the activation of both LEPR and ADRB2, resulting in increased ROS production. These findings highlight LEPR and ADRB2 as potential biomarkers and therapeutic targets in TNBC.

Pristimerin Promotes Ubiquitination of HSPA8 and Activates the VAV1/ERK Pathway to Suppress TNBC Proliferation

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis. The natural compound pristimerin has shown promising anti-tumor effect. Here, it is found that pristimerin significantly triggered the activation of autophagy initiation and induced apoptosis in TNBC. Mechanistically, RNA sequencing revealed that pristimerin activated mitogen-activated protein kinase/extracelluar regulated protein kinases (MAPK/ERK) pathway. Drug affinity responsive target stability and mass spectrometry techniques are employed to confirm the direct binding target of pristimerin. Heat shock protein family A member 8 (HSPA8) is identified and verified by cellular thermal shift assays and surface plasmon resonance assays. The further results suggested that pristimerin promoted the ubiquitination and degradation of HSPA8, leading to a decrease in the degradation of Vac Guanine Nucleotide Exchange Factor 1 (VAV1), a downstream client protein of HSPA8 which plays a crucial role in activating the ERK pathway. Importantly, knockdown of HSPA8 or VAV1 significantly impaired the anticancer activity of pristimerin on TNBC cells. Additionally, pristimerin significantly inhibited the migration and invasion of TNBC cells and enhanced the sensitivity of TNBC cells to doxorubicin. Collectively, this study provides the initial evidence that pristimerin directly targets HSPA8 to activate the VAV1/ERK pathway, thereby promoting cell autophagy and apoptosis.

Gold Nanoparticle Inhibits the Tumor-Associated Macrophage M2 Polarization by Inhibiting m6A Methylation-Dependent ATG5/Autophagy in Prostate Cancer

Background: This study aims to study how gold nanoparticles (AuNPs) function in the recruitment and polarization of tumor-associated macrophages (TAMs) in hormone-sensitive prostate cancer (HSPC) and castration-resistant prostate cancer (CRPC). Methods: Phorbol ester (PMA)-treated THP-1 cells were cocultured with LNCaP or PC3 cells to simulate TAMs. Macrophage M2 polarization levels were detected using flow cytometry and M2 marker determination. ATG5 expression was detected by western blotting. Luciferase reporter assay was used to analyze the N6-methyladenosine (m6A) site activity of ATG5 3' untranslated regions (3'-UTRs). Methylated RNA immune precipitation (MeRIP)-quantitative polymerase chain reaction (qPCR) was performed to determine the m6A levels at ATG5 3'-UTR. Xenograft mouse models were used to determine the function of AuNPs in vivo. Results: Macrophages exhibited reduced M2 polarization in both HSPC and CRPC cells after AuNP treatment which was prevented by induction of autophagy. AuNP treatment decreased the m6A levels in the 3'-UTR of ATG5. Mutational analysis of potential m6A sites within ATG5 3'-UTR revealed that these sites were required for AuNP regulation, indicating that AuNPs inhibited ATG5 levels in an m6A-dependent manner. The mouse model revealed that AuNPs significantly reduced the M2 polarization of TAMs in an autophagy-dependent manner in vivo. This suggests that AuNPs inhibit tumor growth in vivo partially through targeting M2 TAM. Conclusion: The ATG5/autophagy pathway is inhibited by AuNP treatment in an METTL3/m6A-dependent manner. AuNPs inhibit the TAM M2 polarization in HSPC and CRPC by inhibiting ATG5/autophagy.

Autophagy in cancer development, immune evasion, and drug resistance

Macroautophagy/autophagy is a highly conserved evolutionary mechanism involving lysosomes for the degradation of cytoplasmic components including organelles. The constitutive, basal level of autophagy is fundamental for preserving cellular homeostasis; however, alterations in autophagy can cause disease pathogenesis, including cancer. The role of autophagy in cancer is particularly complicated, since this process acts both as a tumor suppressor in precancerous stages but facilitates tumor progression during carcinogenesis and later stages of cancer progression. This shift between anti-tumor and pro-tumor roles may be influenced by genetic and environmental factors modulating key pathways such as those involving autophagy-related proteins, the PI3K-AKT-MTOR axis, and AMPK, which often show dysregulation in tumors. Autophagy regulates various cellular functions, including metabolism of glucose, glutamine, and lipids, cell proliferation, metastasis, and several types of cell death (apoptosis, ferroptosis, necroptosis and immunogenic cell death). These multifaceted roles demonstrate the potential of autophagy to affect DNA damage repair, cell death pathways, proliferation and survival, which are critical in determining cancer cells' response to chemotherapy. Therefore, targeting autophagy pathways presents a promising strategy to combat chemoresistance, as one of the major reasons for the failure in cancer patient treatment. Furthermore, autophagy modulates immune evasion and the function of immune cells such as T cells and dendritic cells, influencing the tumor microenvironment and cancer's biological behavior. However, the therapeutic targeting of autophagy is complex due to its dual role in promoting survival and inducing cell death in cancer cells, highlighting the need for strategies that consider both the beneficial and detrimental effects of autophagy modulation in cancer therapy. Hence, both inducers and inhibitors of autophagy have been introduced for the treatment of cancer. This review emphasizes the intricate interplay between autophagy, tumor biology, and immune responses, offering insights into potential therapeutic approaches that deploy autophagy in the cancer suppression.

Nanotherapeutics for Macrophage Network Modulation in Tumor Microenvironments: Targets and Tools

Macrophage is an important component in the tumor immune microenvironment, which exerts significant influence on tumor development and metastasis. Due to their dual nature of promoting and suppressing inflammation, macrophages can serve as both targets for tumor immunotherapy and tools for treating malignancies. However, the abundant infiltration of tumor-associated macrophages dominated by an immunosuppressive phenotype maintains a pro-tumor microenvironment, and engineering macrophages using nanotechnology to manipulate the tumor immune microenvironment represent a feasible approach for cancer immunotherapy. Additionally, considering the phagocytic and specifically tumor-targeting capabilities of M1 macrophages, macrophages manipulated through cellular engineering and nanotechnology, as well as macrophage-derived exosomes and macrophage membranes, can also become effective tools for cancer treatment. In conclusion, nanotherapeutics targeting macrophages remains immense potential for the development of macrophage-mediated tumor treatment methods and will further enhance our understanding, diagnosis, and treatment of various malignants.

Shikonin Induces Autophagy and Apoptosis in Esophageal Cancer EC9706 Cells by Regulating the AMPK/mTOR/ULK Axis

Shikonin is a plant medicine extracted from Lithospermum, which dominate influential antioxidant and antitumor effect. Here, we report that shikonin was capable of inducing human esophageal cancer EC9706 cell apoptosis and autophagy, in a time- and dose-dependent manner. Shikonin exposure repressed cell viability and migration and invasion capabilities and caused EC9706 cell autophagy and apoptosis by activating the AMPK/mTOR/ULK axis. Autophagy inhibition secured EC9706 cells against shikonin-induced autophagy and apoptosis and reversed the upregulation of AMPK and ULK phosphorylation and downregulation of mTOR phosphorylation provoked by shikonin. In summary, shikonin instigates EC9706 cell apoptosis and autophagy using the target AMPK/mTOR/ULK signal pathway axis, which provides a potential new target to treat human esophageal cancer.

Macrophages and tumor-associated macrophages in the senescent microenvironment: From immunosuppressive TME to targeted tumor therapy

In-depth studies of the tumor microenvironment (TME) have helped to elucidate its cancer-promoting mechanisms and inherent characteristics. Cellular senescence, which acts as a response to injury and can the release of senescence-associated secretory phenotypes (SASPs). These SASPs release various cytokines, chemokines, and growth factors, remodeling the TME. This continual development of a senescent environment could be associated with chronic inflammation and immunosuppressive TME. Additionally, SASPs could influence the phenotype and function of macrophages, leading to the recruitment of tumor-associated macrophages (TAMs). This contributes to tumor proliferation and metastasis in the senescent microenvironment, working in tandem with immune regulation, angiogenesis, and therapeutic resistance. This comprehensive review covers the evolving nature of the senescent microenvironment, macrophages, and TAMs in tumor development. We also explored the links between chronic inflammation, immunosuppressive TME, cellular senescence, and macrophages. Moreover, we compiled various tumor-specific treatment strategies centered on cellular senescence and the current challenges in cellular senescence research. This study aimed to clarify the mechanism of macrophages and the senescent microenvironment in tumor progression and advance the development of targeted tumor therapies.

Atg5 deficiency in macrophages protects against kidney fibrosis via the CCR6-CCL20 axis

BACKGROUND

Autophagy is a lysosome-dependent degradation pathway that regulates macrophage activation, differentiation, and polarization. Autophagy related 5 (Atg5) is a key protein involved in phagocytic membrane elongation in autophagic vesicles that forms a complex with Atg12 and Atg16L1. Alterations in Atg5 are related to both acute and chronic kidney diseases in experimental models. However, the role of macrophage-expressed Atg5 in acute kidney injury remains unclear.

METHODS

Using a myeloid cell-specific Atg5 knockout (MΦ atg5-/-) mouse, we established renal ischemia/reperfusion and unilateral ureteral obstruction models to evaluate the role of macrophage Atg5 in renal macrophage migration and fibrosis.

RESULTS

Based on changes in the serum urea nitrogen and creatinine levels, Atg5 deletion had a minimal effect on renal function in the early stages after mild injury; however, MΦ atg5-/- mice had reduced renal fibrosis and reduced macrophage recruitment after 4 weeks of ischemia/reperfusion injury and 2 weeks of unilateral ureteral obstruction injury. Atg5 deficiency impaired the CCL20-CCR6 axis after severe ischemic kidneys. Chemotactic responses of bone marrow-derived monocytes (BMDMs) from MΦ atg5-/- mice to CCL20 were significantly attenuated compared with those of wild-type BMDMs, and this might be caused by the inhibition of PI3K, AKT, and ERK1/2 activation.

CONCLUSIONS

Our data indicate that Atg5 deficiency decreased macrophage migration by impairing the CCL20-CCR6 axis and inhibited M2 polarization, thereby improving kidney fibrosis.

Low-dose cadmium telluride quantum dots trigger M1 polarization in macrophages through mTOR-mediated transcription factor EB activation

The increasing application of quantum dots (QDs) increases interactions with organisms. The inflammatory imbalance is a significant manifestation of immunotoxicity. Macrophages maintain inflammatory homeostasis. Using macrophages differentiated by phorbol 12-myristate 13-acetate-induced THP-1 cells as models, the study found that low-dose (5 μM) cadmium telluride QDs (CdTe-QDs) hindered monocyte-macrophage differentiation. CD11b is a surface marker of macrophage, and the addition of CdTe-QDs during induction resulted in a decrease in CD11b expression. Moreover, exposure of differentiated THP-1 macrophage (dTHP-1) to 5 μM CdTe-QDs led to the initiation of M1 polarization. This was indicated by the increased surface marker CD86 expression, along with elevated level of NF-κB and IL-1β proteins. The potential mechanisms are being explored. The transcription factor EB (TFEB) plays a significant role in immune regulation and serves as a crucial regulator of the autophagic lysosomal pathway. After exposed to CdTe-QDs, TFEB activation-mediated autophagy and M1 polarization were observed to occur simultaneously in dTHP-1. The mTOR signaling pathway contributed to TFEB activation induced by CdTe-QDs. However, mTOR-independent activation of TFEB failed to promote M1 polarization. These results suggest that mTOR-TFEB is an advantageous target to enhance the biocompatibility of CdTe-QDs.

Emerging Roles of Macrophage Polarization in Osteoarthritis: Mechanisms and Therapeutic Strategies

Osteoarthritis (OA) is the most common chronic degenerative joint disease in middle-aged and elderly people, characterized by joint pain and dysfunction. Macrophages are key players in OA pathology, and their activation state has been studied extensively. Various studies have suggested that macrophages might respond to stimuli in their microenvironment by changing their phenotypes to pro-inflammatory or anti-inflammatory phenotypes, which is called macrophage polarization. Macrophages accumulate and become polarized (M1 or M2) in many tissues, such as synovium, adipose tissue, bone marrow, and bone mesenchymal tissues in joints, while resident macrophages as well as other stromal cells, including fibroblasts, chondrocytes, and osteoblasts, form the joint and function as an integrated unit. In this study, we focus exclusively on synovial macrophages, adipose tissue macrophages, and osteoclasts, to investigate their roles in the development of OA. We review recent key findings related to macrophage polarization and OA, including pathogenesis, molecular pathways, and therapeutics. We summarize several signaling pathways in macrophage reprogramming related to OA, including NF-κB, MAPK, TGF-β, JAK/STAT, PI3K/Akt/mTOR, and NLRP3. Of note, despite the increasing availability of treatments for osteoarthritis, like intra-articular injections, surgery, and cellular therapy, the demand for more effective clinical therapies has remained steady. Therefore, we also describe the current prospective therapeutic methods that deem macrophage polarization to be a therapeutic target, including physical stimulus, chemical compounds, and biological molecules, to enhance cartilage repair and alleviate the progression of OA.

BOP1 contributes to the activation of autophagy in polycystic ovary syndrome via nucleolar stress response

Abnormal autophagy is one of the vital features in polycystic ovary syndrome (PCOS). However, the underlying molecular mechanisms remain unelucidated. In this study, we aimed to investigate whether Block of Proliferation 1 (BOP1) is involved in the onset of autophagy activation of granulosa cells in PCOS. Firstly, we found that BOP1 expression was significantly down-regulated in the ovaries of PCOS mice, which was associated with the development of PCOS. Next, local injection of lentiviral vectors in the ovary for the overexpression of BOP1 significantly alleviated the phenotypes of elevated androgens, disturbed estrous cycle, and abnormal follicular development in PCOS mice. Subsequently, we found that knockdown of BOP1 activated autophagy of granulosa cells in the in vitro experiments, whereas overexpression of BOP1 inhibited autophagy in both in vivo and in vitro models. Mechanistically, BOP1 knockdown triggered the nucleolus stress response, which caused RPL11 to be released from the nucleolus into the nucleoplasm and inhibited the E3 ubiquitination ligase of MDM2, thereby enhancing the stability of p53. Subsequently, P53 inhibited mTOR, thereby activating autophagy in granulosa cells. In addition, the mRNA level of BOP1 was negatively correlated with antral follicle count (AFC), body-mass index (BMI), serum androgen levels, and anti-Mullerian hormone (AMH) in patients with PCOS. In summary, our study demonstrates that BOP1 downregulation inhibits mTOR phosphorylation through activation of the p53-dependent nucleolus stress response, which subsequently contributes to aberrant autophagy in granulosa cells, revealing that BOP1 may be a key target for probing the mechanisms of PCOS.

Unfolding the Complexity of Exosome-Cellular Interactions on Tumour Immunity and Their Clinical Prospects in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy situated in the posterolateral nasopharynx. NPC poses grave concerns in Southeast Asia due to its late diagnosis. Together with resistance to standard treatment combining chemo- and radiotherapy, NPC presents high metastatic rates and common recurrence. Despite advancements in immune-checkpoint inhibitors (ICIs) and cytotoxic-T-lymphocytes (CTLs)-based cellular therapy, the exhaustive T cell profile and other signs of immunosuppression within the NPC tumour microenvironment (TME) remain as concerns to immunotherapy response. Exosomes, extracellular vesicles of 30-150 nm in diameter, are increasingly studied and linked to tumourigenesis in oncology. These bilipid-membrane-bound vesicles are packaged with a variety of signalling molecules, mediating cell-cell communications. Within the TME, exosomes can originate from tumour, immune, or stromal cells. Although there are studies on tumour-derived exosomes (TEX) in NPC and their effects on tumour processes like angiogenesis, metastasis, therapeutic resistance, there is a lack of research on their involvement in immune evasion. In this review, we aim to enhance the comprehension of how NPC TEX contribute to cellular immunosuppression. Furthermore, considering the detectability of TEX in bodily fluids, we will also discuss the potential development of TEX-related biomarkers for liquid biopsy in NPC as this could facilitate early diagnosis and prognostication of the disease.

The dual role of autophagy in the regulation of cancer treatment

As a catabolic process, autophagy through lysosomes degrades defective and damaged cellular materials to support homeostasis in stressful conditions. Therefore, autophagy dysregulation is associated with the induction of several human pathologies, including cancer. Although the role of autophagy in cancer progression has been extensively studied, many issues need to be addressed. The available evidence suggest that autophagy shows both cytoprotective and cytotoxic mechanisms. This dual role of autophagy in cancer has supplied a renewed interest in the development of novel and effective cancer therapies. Considering this, a deeper understanding of the molecular mechanisms of autophagy in cancer treatment is crucial. This article provides a summary of the recent advances regarding the dual and different mechanisms of autophagy-mediated therapeutic efficacy in cancer.

Breast cancer cells and adipocytes in hypoxia: metabolism regulation

Adipocytes play a significant role in breast cancer due to the unique histological structure of the breast. These have not only been detected adjacent to breast cancer cells but they have also been implicated in cancer development. Adipocytes in obese individuals and tumor microenvironment (TME) have a common feature, that is, hypoxia. The increased expression of hypoxia-inducible factor (HIF)-1α is known to alter the metabolism and functions of adipocytes. In this study, we described the mechanism linking the hypoxia-sensing pathway manifested by HIF to adipocytes and breast cancer and discussed the mechanism underlying the role of hypoxic adipocytes in breast cancer development from the perspective of metabolic remodeling. The processes and pathways in hypoxic adipocytes could be a promising target in breast cancer therapy.

Macelignan prevents colorectal cancer metastasis by inhibiting M2 macrophage polarization

BACKGROUND

Colorectal cancer (CRC) metastasis is a complicated process that not only involves tumor cells but also the effects of M2 type tumor-associated macrophages, a key component of the tumor microenvironment (TME), act a crucial role in cancer metastasis. Macelignan, an orally active lignan isolated from Myristica fragrans, possesses various beneficial biological activities, including anti-cancer effects, but its effect on macrophage polarization in the TME remains unknown.

PURPOSE

To evaluate the inhibitory potency and prospective mechanism of macelignan on M2 polarization of macrophages and CRC metastasis.

METHODS

The polarization and specific mechanism of M1 and M2 macrophage regulated by macelignan were determined by western blot, flow cytometry, immunofluorescence and network pharmacology. In vitro and in vivo function assays were performed to investigate the roles of macelignan in CRC metastasis.

RESULTS

Macelignan efficiently inhibited IL-4/13-induced polarization of M2 macrophages by suppressing the PI3K/AKT pathway in a reactive oxygen species (ROS)-dependent manner. The proportion of CD206+ M2 macrophages was elevated in patients with CRC liver metastasis. Furthermore, macelignan inhibited M2 macrophage-mediated metastasis of CRC cells in vitro and in vivo. Mechanistically, macelignan reduced secretion of IL-1β from M2 macrophages, which in turn blocked NF-κB p65 nuclear translocation and inhibited metastasis.

CONCLUSION

Macelignan suppressed macrophage M2 polarization via ROS-mediated PI3K/AKT signaling pathway, thus preventing IL-1β/NF-κB-dependent CRC metastasis. In the present study, we reveal a previously unrecognized mechanism of macelignan in the prevention of CRC metastasis and demonstrate its effectively and safely therapeutic potential in CRC treatment.

Ultrasmall MnOx Nanodots Catalyze Glucose for Reactive Oxygen Species‐Dependent Sequential Anti‐Infection and Regeneration Therapy

The management of diabetic wounds poses significant challenges due to persistent bacterial infections and chronic inflammation caused by hyperglycemia. Herein, a sequential two‐phase treatment strategy involving a reactive oxygen species (ROS) burst in the first phase for anti‐infection is proposed, followed by a benign level of ROS in the second phase for wound regeneration. To this end, ultra‐small manganese oxide nanodots (BM‐NDs) are incorporated into a gelatin methacrylamide (GelMA) hydrogel via a ROS‐responsive linker to form GelMA@BM dressing. The BM‐NDs catalyze a self‐cascade reaction that decomposes glucose into hydrogen peroxide, generates hydroxyl radicals (·OH), and simultaneously depletes glutathione. Upon application on diabetic wounds, BM‐NDs are rapidly released from the hydrogel due to endogenous ROS exposure, leading to high levels of ·OH that effectively eliminate bacteria and promote macrophage polarization to M1 phenotype, thereby facilitating phagocytosis of bacteria. With the consumption of glucose and degradation of BM‐NDs, ROS in the wound area declines to a benign level, which stimulates polarization of M2 macrophages and promotes wound healing. This two‐phase treatment strategy based on GelMA@BM dressing demonstrates potent antibacterial and pro‐healing efficacy, showcasing its potential for clinical translation.

Inhibition of soluble epoxide hydrolase relieves adipose inflammation via modulating M1/M2 macrophage polarization to alleviate airway inflammation and hyperresponsiveness in obese asthma

Obesityincreasestheriskofasthma and tends to enhance the asthma severity, however, its mechanism is not fully elucidated. The expansion of adipose tissue in obesity is accompanied by the accumulation of adiposetissue macrophages (ATMs) that could contribute to alow-gradeinflammationstate. In this study, we researched the regulatory role of soluble epoxide hydrolase (sEH) on ATMs-mediated inflammation in obese asthma. A mouse model of obese asthma that induced by high-fat diet (HFD) feeding and Ovalbumin (OVA) sensitization was employed to investigate the effects of AUDA, a sEH inhibitor (sEHi), on airway inflammation, airway hyperresponsivenesss (AHR) and pulmonary pathological changes. In addition to alleviating the key features of asthma in obese mice, we confirmed that AUDA reduced the expression of pro-inflammatory factor, such as interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumornecrosisfactor-α (TNF-α) in adipose tissue and serum. Moreover, AUDA could remarkedly reduce Lipopolysaccharide (LPS)-elevated IL-1β, IL-6 and TNF-α in RAW264.7 macrophage cells. Mechanistically, AUDA effectively reduced inflammation in adipose tissue, resulting in reduced systemic inflammation, by inhibiting M1-type macrophage polarization and promoting M2-type macrophage polarization. These processes were found to act through ERK1/2 signaling pathway. Herein, we proved that inhibition of sEH expression helped to mitigate multiple parameters of obese asthma by regulating the balance of M1/M2 macrophage polarization in adipose tissue.

Regulation of alveolar macrophage death in pulmonary fibrosis: a review

Pulmonary fibrosis (PF) is a disease in which excessive extracellular matrix (ECM) accumulation occurs in pulmonary mesenchyme, which induces the destruction of alveolar structures and poor prognosis. Macrophage death is responsible for ECM accumulation after alveolar epithelial injury in PF. Depending on the local micro-environments, macrophages can be polarized to either classically activated (M1) or alternatively activated (M2) macrophage phenotypes. In general, M1 macrophages can promote inflammation and sterilization, stop the continuous damage process and prevent excessive repair, while M2 macrophages are anti-inflammatory and promote tissue repair, and excessive M2 macrophage activity may inhibit the absorption and degradation of ECM. Emerging evidence has revealed that death forms such as pyroptosis mediated by inflammasome affect polarization direction and ultimately lead to the development of PF. Pharmacological manipulation of macrophages death signals may serve as a logical therapeutic strategy for PF. This review will focus on the current state of knowledge regarding the regulation and underlying mechanisms of macrophages and their mediators in the influence of macrophage death on the development of PF. We expect to provide help in developing effective therapeutic strategies in clinical settings.

Targeting autophagy and beyond: Deconvoluting the complexity of Beclin-1 from biological function to cancer therapy

Beclin-1 is the firstly-identified mammalian protein of the autophagy machinery, which functions as a molecular scaffold for the assembly of PI3KC3 (class III phosphatidylinositol 3 kinase) complex, thus controlling autophagy induction and other cellular trafficking events. Notably, there is mounting evidence establishing the implications of Beclin-1 in diverse tumorigenesis processes, including tumor suppression and progression as well as resistance to cancer therapeutics and CSC (cancer stem-like cell) maintenance. More importantly, Beclin-1 has been confirmed as a potential target for the treatment of multiple cancers. In this review, we provide a comprehensive survey of the structure, functions, and regulations of Beclin-1, and we discuss recent advances in understanding the controversial roles of Beclin-1 in oncology. Moreover, we focus on summarizing the targeted Beclin-1-regulating strategies in cancer therapy, providing novel insights into a promising strategy for regulating Beclin-1 to improve cancer therapeutics in the future.

Identification of a venetoclax-resistance prognostic signature base on 6-senescence genes and its clinical significance for acute myeloid leukemia

Background

Satisfactory responses can be obtained for acute myeloid leukemia (AML) treated by Venetoclax (VEN)-based therapy. However, there are still quite a few AML patients (AMLs) resistant to VEN, and it is critical to understand whether VEN-resistance is regulated by senescence.

Methods

Here, we established and validated a signature for predicting AML prognosis based on VEN resistance-related senescence genes (VRSGs). In this study, 51 senescence genes were identified with VEN-resistance in AML. Using LASSO algorithms and multiple AML cohorts, a VEN-resistance senescence prognostic model (VRSP-M) was developed and validated based on 6-senescence genes.

Results

According to the median score of the signature, AMLs were classified into two subtypes. A worse prognosis and more adverse features occurred in the high-risk subtype, including older patients, non-de novo AML, poor cytogenetics, adverse risk of European LeukemiaNet (ELN) 2017 recommendation, and TP53 mutation. Patients in the high-risk subtype were mainly involved in monocyte differentiation, senescence, NADPH oxidases, and PD1 signaling pathway. The model's risk score was significantly associated with VEN-resistance, immune features, and immunotherapy response in AML. In vitro, the IC50 values of ABT-199 (VEN) rose progressively with increasing expression of G6PD and BAG3 in AML cell lines.

Conclusions

The 6-senescence genes prognostic model has significant meaning for the prediction of VEN-resistance, guiding personalized molecularly targeted therapies, and improving AML prognosis.

Macrophage RAGE deficiency prevents myocardial fibrosis by repressing autophagy-mediated macrophage alternative activation

Myocardial fibrosis (MF) is the characteristic pathological feature of various cardiovascular diseases that lead to heart failure (HF) or even fatal outcomes. Alternatively, activated macrophages are involved in the development of fibrosis and tissue remodeling. Although the receptor for advanced glycation end products (RAGE) is involved in MF, its potential role in regulating macrophage function in cardiac fibrosis has not been fully investigated. We aimed to determine the role of macrophage RAGE in transverse aortic constriction (TAC)-induced MF. In this study, we found that RAGE expression was markedly increased in the infiltrated alternatively activated macrophages within mice hearts after TAC. RAGE knockout mice showed less infiltration of alternatively activated macrophages and attenuated cardiac hypertrophy and fibrosis compared to the wild-type mice. Our data suggest that mice with macrophage-specific genetic deletion of RAGE were protected from interstitial fibrosis and cardiac dysfunction when subjected to pressure overload, which led to a decreased proportion of alternatively activated macrophages in heart tissues. Our in vitro experiments demonstrated that RAGE deficiency inhibited the differentiation into alternatively activated macrophages by suppressing autophagy activation. In the co-culture system, in vitro polarization of RAW264.7 macrophages toward an alternatively activated phenotype stimulated the expression of α-smooth muscle actin and collagen in cardiac fibroblasts. However, the knockdown of RAGE and inhibition of autophagy in macrophages showed reduced fibroblast-to-myofibroblast transition (FMT). Collectively, our results suggest that RAGE plays an important role in the recruitment and activation of alternatively activated macrophages by regulating autophagy, which contributes to MF. Thus, blockage of RAGE signaling may be an attractive therapeutic target for the treatment of hypertensive heart disease.

Tumor Metabolism-Rewriting Nanomedicines for Cancer Immunotherapy

Cancer immunotherapy has become an established therapeutic paradigm in oncologic therapy, but its therapeutic efficacy remains unsatisfactory in the majority of cancer patients. Accumulating evidence demonstrates that the metabolically hostile tumor microenvironment (TME), characterized by acidity, deprivation of oxygen and nutrients, and accumulation of immunosuppressive metabolites, promotes the dysfunction of tumor-infiltrating immune cells (TIICs) and thereby compromises the effectiveness of immunotherapy. This indicates the potential role of tumor metabolic intervention in the reinvigoration of antitumor immunity. With the merits of multiple drug codelivery, cell and organelle-specific targeting, controlled drug release, and multimodal therapy, tumor metabolism-rewriting nanomedicines have recently emerged as an attractive strategy to strengthen antitumor immune responses. This review summarizes the current progress in the development of multifunctional tumor metabolism-rewriting nanomedicines for evoking antitumor immunity. A special focus is placed on how these nanomedicines reinvigorate innate or adaptive antitumor immunity by regulating glucose metabolism, amino acid metabolism, lipid metabolism, and nucleotide metabolism at the tumor site. Finally, the prospects and challenges in this emerging field are discussed.

Autophagy suppression facilitates macrophage M2 polarization via increased instability of NF-κB pathway in hepatocellular carcinoma

The tumor microenvironment is a highly heterogeneous circumstance composed of multiple components, while tumor-associated macrophages (TAMs) are major innate immune cells with highly plastic and are always educated by tumor cells to structure an advantageous pro-tumor immune microenvironment. Despite emerging evidence focalizing the role of autophagy in other immune cells, the regulatory mechanism of autophagy in macrophage polarization remains poorly understood. Herein, we demonstrated that hepatocellular carcinoma (HCC) cells educated macrophages toward M2-like phenotype polarization under the condition of coculture. Moreover, we observed that inhibition of macrophage autophagy promoted M2-like macrophage polarization, while the tendency was impeded when autophagy was motivated. Mechanistically, macrophage autophagy inhibition inactivates the NF-κB pathway by increasing the instability of TAB3 via ubiquitination degradation, which leads to the M2-like phenotype polarization of macrophages. Both immunohistochemistry staining using human HCC tissues and experiment in vivo verified autophagy inhibition is correlated with M2 macrophage polarization. Altogether, we illustrated that macrophage autophagy was involved in the process of HCC cells domesticating M2 macrophage polarization via the NF-κB pathway. These results provide a new target to interfere with the polarization of macrophages to M2-like phenotype during HCC progression.

Research Progress on Molecular Subtyping and Modern Treatment of Triple-Negative Breast Cancer

Breast cancer has become the most common malignant tumor worldwide. Triple-negative breast cancer (TNBC) is a type of breast cancer that is negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Compared with other molecular subtypes of breast cancer, TNBC is the most aggressive and highly heterogeneous. TNBC is insensitive to endocrine and anti-HER2 therapy, and chemotherapy is currently the main systemic treatment. With the continuous development of detection techniques and deepening research on TNBC molecular subtypes, drugs targeting immune checkpoints and different targets have emerged, such as atezolizumab, pembrolizumab, poly (ADP-ribose) polymerase (PARP) inhibitors, trophoblast cell-surface antigen 2 (TROP-2), and antibody-drug conjugates. These therapies provide new hope for TNBC treatment. Based on the analysis and classification of TNBC, this article summarizes the immunotherapy, targeted therapy, and new treatment combinations, providing references for the precise treatment of TNBC in the future.

Vinblastine resets tumor-associated macrophages toward M1 phenotype and promotes antitumor immune response

BACKGROUND

Massive tumor-associated macrophage (TAM) infiltration is observed in many tumors, which usually display the immune-suppressive M2-like phenotype but can also be converted to an M1-like antitumor phenotype due to their high degree of plasticity. The macrophage polarization state is associated with changes in cell shape, macrophage morphology is associated with activation status. M1 macrophages appeared large and rounded, while M2 macrophages were stretched and elongated cells. Manipulating cell morphology has been shown to affect the polarization state of macrophages. The shape of the cell is largely dependent on cytoskeletal proteins, especially, microtubules. As a microtubule-targetting drug, vinblastine (VBL) has been used in chemotherapy. However, no study to date has explored the effect of VBL on TAM shape changes and its role in tumor immune response.

METHOD

We used fluorescent staining of the cytoskeleton and quantitative analysis to reveal the morphological differences between M0, M1, M2, TAM and VBL-treated TAM. Flow cytometry was used to confirm the polarization states of these macrophages using a cell surface marker-based classification. In vivo antibody depletion experiments in tumor mouse models were performed to test whether macrophages and CD8+ T cell populations were required for the antitumor effect of VBL. VBL and anti-PD-1 combination therapy was then investigated in comparison with monotherapy. RNA-seq of TAM of treated and untreated with VBL was performed to explore the changes in pathway activities. siRNA mediated knockdown experiments were performed to verify the target pathway that was affected by VBL treatment.

RESULTS

Here, we showed that VBL, an antineoplastic agent that destabilizes microtubule, drove macrophage polarization into the M1-like phenotype both in vitro and in tumor models. The antitumor effect of VBL was attenuated in the absence of macrophages or CD8+ T cells. Mechanistically, VBL induces the activation of NF-κB and Cyba-dependent reactive oxygen species generation, thus polarizing TAMs to the M1 phenotype. In parallel, VBL promotes the nuclear translocation of transcription factor EB, inducing lysosome biogenesis and a dramatic increase in phagocytic activity in macrophages.

CONCLUSIONS

This study explored whether manipulating cellular morphology affects macrophage polarization and consequently induces an antitumor response. Our data reveal a previously unrecognized antitumor mechanism of VBL and suggest a drug repurposing strategy combining VBL with immune checkpoint inhibitors to improve malignant tumor immunotherapy.

Metabolism, metabolites, and macrophages in cancer

Tumour-associated macrophages (TAMs) are crucial components of the tumour microenvironment and play a significant role in tumour development and drug resistance by creating an immunosuppressive microenvironment. Macrophages are essential components of both the innate and adaptive immune systems and contribute to pathogen resistance and the regulation of organism homeostasis. Macrophage function and polarization are closely linked to altered metabolism. Generally, M1 macrophages rely primarily on aerobic glycolysis, whereas M2 macrophages depend on oxidative metabolism. Metabolic studies have revealed that the metabolic signature of TAMs and metabolites in the tumour microenvironment regulate the function and polarization of TAMs. However, the precise effects of metabolic reprogramming on tumours and TAMs remain incompletely understood. In this review, we discuss the impact of metabolic pathways on macrophage function and polarization as well as potential strategies for reprogramming macrophage metabolism in cancer treatment.

Rapamycin Inhibits Osteoclastogenesis and Prevents LPS-Induced Alveolar Bone Loss by Oxidative Stress Suppression

Periodontitis is a progressive inflammatory skeletal disease characterized by periodontal tissue destruction, alveolar bone resorption, and tooth loss. Chronic inflammatory response and excessive osteoclastogenesis play essential roles in periodontitis progression. Unfortunately, the pathogenesis that contributes to periodontitis remains unclear. As a specific inhibitor of the mTOR (mammalian/mechanistic target of rapamycin) signaling pathway and the most common autophagy activator, rapamycin plays a vital role in regulating various cellular processes. The present study investigated the effects of rapamycin on osteoclast (OC) formation in vitro and its effects on the rat periodontitis model. The results showed that rapamycin inhibited OC formation in a dose-dependent manner by up-regulating the Nrf2/GCLC signaling pathway, thus suppressing the intracellular redox status, as measured by 2',7'-dichlorofluorescein diacetate and MitoSOX. In addition, rather than simply increasing the autophagosome formation, rapamycin increased the autophagy flux during OC formation. Importantly, the anti-oxidative effect of rapamycin was regulated by an increase in autophagy flux, which could be attenuated by blocking autophagy with bafilomycin A1. In line with the in vitro results, rapamycin treatment attenuated alveolar bone resorption in rats with lipopolysaccharide-induced periodontitis in a dose-dependent manner, as assessed by micro-computed tomography, hematoxylin-eosin staining, and tartrate-resistant acid phosphatase staining. Besides, high-dose rapamycin treatment could reduce the serum levels of proinflammatory factors and oxidative stress in periodontitis rats. In conclusion, this study expanded our understanding of rapamycin's role in OC formation and protection from inflammatory bone diseases.

Scutellarin Acts via MAPKs Pathway to Promote M2 Polarization of Microglial Cells

Scutellarin, an herbal agent, is known to possess anti-oxidant and anti-inflammatory properties. In activated microglia, it has been reported that this is achieved through acting on the MAPKs, a key pathway that regulates microglia activation. This study sought to determine if scutellarin would affect the commonly described microglia phenotypes, namely, M1 and M2, thought to contribute to pro- and anti-inflammatory roles, respectively. This is in consideration of its potential effect on the polarization of microglia phenotypes that are featured prominently in cerebral ischemia. For this purpose, we have used an experimentally induced cerebral ischemia rat model and LPS-stimulated BV-2 cell model. Thus, by Western blot and immunofluorescence, we show here a noticeable increase in expression of M2 microglia markers, namely, CD206, Arg1, YM1/2, IL-4 and IL-10 in activated microglia both in vivo and in vitro. Besides, we have confirmed that Scutellarin upregulated expression of Arg1, IL-10 and IL-4 in medium supernatants of BV-2 microglia. Remarkably, scutellarin treatment markedly augmented the increased expression of the respective markers in activated microglia. It is therefore suggested scutellarin can exert the polarization of activated microglia from M1 to M2 phenotype. Because M1 microglia are commonly known to be proinflammatory, while M2 microglia are anti-inflammatory and neuroprotective effect, it stands to reason therefore that with the increase of M2 microglia which became predominant by scutellarin, the local inflammatory response is ameliorated. More importantly, we have found that scutellarin promotes the M2 polarization through inhibiting the JNK and p38 signaling pathways, and concomitantly augmenting the ERK1/2 signaling pathway. This lends its strong support from observations in LPS activated BV-2 microglia treated with p38 and JNK inhibitors in which expression of M2 markers was increased; on the other hand, in cells subjected to ERK1/2 inhibitor treatment, the expression was suppressed. In light of the above, MAPKs pathway is deemed to be a potential therapeutic target of scutellarin in mitigating microglia mediated neuroinflammation in activated microglia.

Towards dual function of autophagy in breast cancer: A potent regulator of tumor progression and therapy response

As a devastating disease, breast cancer has been responsible for decrease in life expectancy of females and its morbidity and mortality are high. Breast cancer is the most common tumor in females and its treatment has been based on employment of surgical resection, chemotherapy and radiotherapy. The changes in biological behavior of breast tumor relies on genomic and epigenetic mutations and depletions as well as dysregulation of molecular mechanisms that autophagy is among them. Autophagy function can be oncogenic in increasing tumorigenesis, and when it has pro-death function, it causes reduction in viability of tumor cells. The carcinogenic function of autophagy in breast tumor is an impediment towards effective therapy of patients, as it can cause drug resistance and radio-resistance. The important hallmarks of breast tumor such as glucose metabolism, proliferation, apoptosis and metastasis can be regulated by autophagy. Oncogenic autophagy can inhibit apoptosis, while it promotes stemness of breast tumor. Moreover, autophagy demonstrates interaction with tumor microenvironment components such as macrophages and its level can be regulated by anti-tumor compounds in breast tumor therapy. The reasons of considering autophagy in breast cancer therapy is its pleiotropic function, dual role (pro-survival and pro-death) and crosstalk with important molecular mechanisms such as apoptosis. Moreover, current review provides a pre-clinical and clinical evaluation of autophagy in breast tumor.

Intelectin enhances the phagocytosis of macrophages via CDC42-WASF2-ARPC2 signaling axis in Megalobrama amblycephala

Intelectin has been identified in various vertebrates and plays an important role in the host immune system. In our previous studies, recombinant Megalobrama amblycephala intelectin (rMaINTL) protein with excellent bacterial binding and agglutination activities enhances the phagocytic and killing activities of macrophages in M. amblycephala; however, the underlying regulatory mechanisms remain unclear. The present study showed that treatment with Aeromonas hydrophila and LPS induced the expression of rMaINTL in macrophages, and its level and distribution in macrophages or kidney tissue markedly increased after incubation or injection with rMaINTL. The cellular structure of macrophages was significantly affected after incubation with rMaINTL, resulting in an increased surface area and pseudopodia extension, which might contribute to enhancing the phagocytic ability of macrophages. Then, digital gene expression profiling analysis of the kidneys from rMaINTL-treated juvenile M. amblycephala identified some phagocytosis-related signaling factors that were enriched in pathways involved in the regulation of the actin cytoskeleton. In addition, qRT-PCR and western blotting verified that rMaINTL upregulated the expression of CDC42, WASF2, and ARPC2 in vitro and in vivo; however, the expression of these proteins was inhibited by a CDC42 inhibitor in macrophages. Moreover, CDC42 mediated the promotion of rMaINTL on actin polymerization by increasing the F-actin/G-actin ratio, which led to the extension of pseudopodia and remodeling of the macrophage cytoskeleton. Furthermore, the enhancement of macrophage phagocytosis by rMaINTL was blocked by the CDC42 inhibitor. These results suggested that rMaINTL induced the expression of CDC42 as well as the downstream signaling molecules WASF2 and ARPC2, thereby facilitating actin polymerization to promote cytoskeletal remodeling and phagocytosis. Overall, MaINTL enhanced the phagocytosis activity of macrophages in M. amblycephala via activation of the CDC42-WASF2-ARPC2 signaling axis.

Antitumor therapy for breast cancer: Focus on tumor-associated macrophages and nanosized drug delivery systems

BACKGROUND

In breast cancer (BC), tumor-associated macrophages (TAMs) are an important component of the tumor microenvironment and are closely related to poor prognosis. A growing number of studies have focused on the role of TAMs in BC progression and therapeutic strategies targeting TAMs. As an emerging treatment, the application of nanosized drug delivery systems (NDDSs) in the treatment of BC by targeting TAMs has attracted much attention.

AIMS

This review is to summarize the characteristics and treatment strategies targeting TAMs in BC and to clarify the applications of NDDSs targeting TAMs in the treatment of BC by targeting TAMs.

MATERIALS & METHODS

The existing results related to characteristics of TAMs in BC, BC treatment strategies by targeting TAMs, and the applications of NDDSs in these strategies are described. Through analyzing these results, the advantages and disadvantages of the treatment strategies using NDDSs are discussed, which could provide advices on designing NDDSs for BC treatment.

RESULTS

TAMs are one of the most prominent noncancer cell types in BC. TAMs not only promote angiogenesis, tumor growth and metastasis but also lead to therapeutic resistance and immunosuppression. Mainly four strategies have been used to target TAMs for BC therapy, which include depleting macrophages, blocking recruitment, reprogramming to attain an anti-tumor phenotype, and increasing phagocytosis. Since NDDSs can efficiently deliver drugs to TAMs with low toxicity, they are promising approaches for targeting TAMs in tumor therapy. NDDSs with various structures can deliver immunotherapeutic agents and nucleic acid therapeutics to TAMs. In addition, NDDSs can realize combination therapies.

DISCUSSION

TAMs play a critical role in the progression of BC. An increasing number of strategies have been proposed to regulate TAMs. Compared with free drugs, NDDSs targeting TAMs improve drug concentration, reduce toxicity and realize combination therapies. However, in order to achieve better therapeutic efficacy, there are still some disadvantages that need to be considered in the design of NDDSs.

CONCLUSION

TAMs play an important role in the progression of BC, and targeting TAMs is a promising strategy for BC therapy. In particular, NDDSs targeting TAMs have unique advantages and are potential treatments for BC.

Role of NCF2 as a potential prognostic factor and immune infiltration indicator in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the major causes of cancer-related deaths globally. The tumor microenvironment (TME) plays a crucial role in the prognosis and treatment of HCC. Hence, it is important to exploit new biomarkers for survival surveillance and TME estimation of HCC.

METHODS

HCC samples data was collected from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) database, and clinical samples were collected from our center. The TME of HCC were explored with ESTIMATE (Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data), ssGSEA (single sample Gene Sets Enrichment Analysis) and CIBERSORT algorithm. Differentially expressed genes were analyzed with functional enrichment analysis. Immunohistochemistry was implemented to validate the results.

RESULTS

Based on TCGA database, we found that Neutrophil Cytosolic Factor 2 (NCF2) was significantly associated with the prognosis of HCC patients, involved in immune-related biological processes of HCC and closely associated with some types of immunocompetent cells. The survival analysis based on NCF2 expression assessed by immunohistochemistry also confirmed that NCF2-positive group had a shorter relapse free survival (RFS) and overall survival (OS) than NCF2-negative group. Multivariate Cox regression revealed NCF2 expression level and lymphovascular space invasion (LVSI) were independent risk factors for HCC patients. Receiver operating characteristic curves showed that the combination of NCF2 and LVSI had higher predictive efficacy on the 1-year RFS rate and 5-year OS rate than each of them alone. Besides, the expression level of NCF2 was positively associated with M0 and M2 macrophages infiltration. Furthermore, NCF2 expression was positively correlated with CSF1, IL4, IL10, CD206, CD163, CSF1R and TGFβ1.

CONCLUSION

We proposed that higher NCF2 expression predicted an adverse prognosis and more M2 macrophages infiltration in HCC patients.

Natural products targeting macrophages in tumor microenvironment are a source of potential antitumor agents

BACKGROUND

Macrophages are one of the major cell types in the immune system and are closely related to tumor development, which can be polarized into M1 type with anti-tumor activity or M2 type with pro-tumor activity. The infiltration of more macrophages into tumor predicts poorer prognosis due to their more exhibition of M2 phenotype under the influence of many factors in the tumor microenvironment (TME). Therefore, reverse of M2 macrophage polarization in TME is conducive to the suppression of tumor deterioration and understanding the influencing factors of macrophage polarization is helpful to provide new ideas for the subsequent targeting macrophages for tumor therapy.

PURPOSE

This review summarizes the effects of TME on macrophage polarization and natural products against M2 macrophage polarization, which may provide some directions for tumor therapy.

METHODS

The search of relevant literature was conducted using the PubMed, Science Direct, CNKI and Web of Science databases with the search terms "macrophage", "tumor microenvironment", "natural product" and "tumor".

RESULTS

The mutual transformation of M1 and M2 phenotypes in macrophages is influenced by many factors. Tumor cells affect the polarization of macrophages by regulating the expression of genes and proteins and the secretion of cytokines. The expression of some genes or proteins in macrophages is also related to their own polarization. Many natural products can reverse M2 polarization of macrophages which has been summarized in this review.

CONCLUSION

Regulation of macrophage polarization in TME can inhibit tumor development, and natural products have the potential to impede tumor development by regulating macrophage polarization.

A novel therapeutic approach for IPF: Based on the "Autophagy - Apoptosis" balance regulation of Zukamu Granules in alveolar macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Zukamu Granules (ZKMG) is one of the representative Uygur patent drugs widely used in China, which is included in the National Essential Drugs List (2018 edition). As the first choice for common cold treatment in Uygur medicine theory, it has unique anti-inflammatory and antitussive efficacy.

AIM OF THE STUDY

According to the recent inflammatory hypothesis, the abnormal proliferation, autophagy and apoptosis process of lung cells especially alveolar macrophages (AMs) may play an important role in the progress of idiopathic pulmonary fibrosis (IPF). Therefore, we came up with a novel treatment approach for IPF by regulating the balance of AMs "autophagy - apoptosis", and took ZKMG as the sample drug for our research.

MATERIALS AND METHODS

Network pharmacology approach was conducted to predict the active components and intersected targets between ZKMG and inflammation. PPI network, GO and KEGG enrichment analysis were screened and analyzed to predict the anti-inflammatory mechanism of ZKMG. Biological experiment adopted from 128 rats, and hematoxylin-eosin staining, flow cytometry and RT-PCR were performed to examine the pathological morphology, HYP contents in lung tissue, AMs counting, AMs apoptosis, AMs phagocytosis rate, mRNA relative quantity determination of 3 key factors associated with AMs "autophagy - apoptosis" and mRNA relative quantity determination of AMs surface receptor signaling pathway.

RESULTS

The predicted results showed that the mechanism of ZKMG in anti-inflammatory was related to the response and elimination of inflammatory stimuli, the intervention of apoptosis and surface receptor signaling pathways of cells. The verification experiments showed that excessive apoptosis and insufficient autophagy of AMs always existed in the progression of IPF. ZKMG could inhibit AMs proliferation, significantly reduce AMs apoptosis rate, intervene the binding of the Bcl-2 to Beclin 1, inhibit the Caspase 3 activation, stimulate the enhancement of AMs phagocytosis, and inhibit the high expression of TLR4/MyD88/NF-κB surface receptor signaling pathway, which may partly retard the fibrosis process.

CONCLUSION

By inhibiting proliferation, enhancing phagocytosis, inhibiting the formation of Bcl-2 complex, and inhibiting the high expression of MYD88-dependent TLR4 signaling pathway, ZKMG can regulate the balance of AMs "autophagy - apoptosis" in the alveolitis stage to retard the fibrosis process partly. With a comprehensive strategy of "target prediction - experimental verification", we have demonstrated that inhibiting the apoptosis and promoting autophagy activity of AMs may suggest a new perspective for IPF treatment, which would provide reference for the subsequent development.

Cardamonin suppresses pro-tumor function of macrophages by decreasing M2 polarization on ovarian cancer cells via mTOR inhibition

Ovarian cancer is the most fatal tumor characterized by an abundance of tumor-associated macrophage (TAM) infiltrations in women. Functional TAMs, which mainly present M2-like phenotypes and perform key functions on tumor progress, have been considered an attractive target for ovarian cancer therapy. Cardamonin showed an excellent antitumor activity in multiple tumor cells. This study aimed to investigate the role of cardamonin on TAMs. With the conditioned medium of ovarian cancer cells, macrophages were induced to TAMs and, accordingly, promoted the proliferation, migration, and invasion of ovarian cancer cells. Cardamonin suppressed alternatively activated (M2) polarization of TAMs and downregulated TAM-secreted tumorigenic factors, thereby hindering the pro-tumor function of TAMs on ovarian cancer cells. Moreover, cardamonin inhibited tumor growth in xenograft nude mice and lowered the expression of CD163 and CD206. Mechanistically, cardamonin inhibited the phosphorylation of mammalian target of rapamycin (mTOR) and signal transducer and activator of transcription 3 (STAT3), resulting in the suppression of M2 polarization. Furthermore, STAT3 is tightly related with mTOR activity. Altogether, these findings implied that cardamonin suppresses the pro-tumor function of TAMs by decreasing M2 polarization via mTOR inhibition, and cardamonin may be a potential therapeutic agent for ovarian cancer.

PHGDH Inhibitor CBR-5884 Inhibits Epithelial Ovarian Cancer Progression via ROS/Wnt/β-Catenin Pathway and Plays a Synergistic Role with PARP Inhibitor Olaparib

PHGDH attaches importance to serine biosynthesis in cancer cells and maintaining mitochondrial redox homeostasis. However, the role of PHGDH inhibitor CBR-5884 in cell ROS level and its downstream pathways has not been explored in epithelial ovarian cancer. Thus, we investigated the function and possible mechanism of PHGDH inhibitor CBR-5884 on epithelial ovarian cancer in vitro and in vivo. A2780, OVCAR3, and ES-2 were treated with CBR-5884 at different concentrations or different time points. Results showed that CBR-5884 inhibited epithelial ovarian cancer cell proliferation, migration, and invasion and increases cell ROS level. Meanwhile, CBR-5884 exerts antitumor effect through activating ROS/Wnt/β-catenin pathway. Besides, CBR-5884 exerts antitumor effect in vivo. What's more, we explored the effect of CBR-5884 with or without PARP inhibitor Olaparib, which showed that the two together had a larger effect. In conclusion, PHGDH inhibitor CBR-5884 inhibits epithelial ovarian cancer proliferation, migration, and invasion through activating ROS/Wnt/β-catenin pathway and plays a synergistic role with PARP inhibitor olaparib, which provided a theoretical basis for PHGDH inhibitor CBR-5884 in clinical treatment.

Progress in preclinical studies of macrophage autophagy in the regulation of ALI/ARDS

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical clinical syndrome with high morbidity and mortality that poses a major challenge in critical care medicine. The development of ALI/ARDS involves excessive inflammatory response, and macrophage autophagy plays an important role in regulating the inflammatory response in ALI/ARDS. In this paper, we review the effects of autophagy in regulating macrophage function, discuss the roles of macrophage autophagy in ALI/ARDS, and highlight drugs and other interventions that can modulate macrophage autophagy in ALI/ARDS to improve the understanding of the mechanism of macrophage autophagy in ALI/ARDS and provide new ideas and further research directions for the treatment of ALI/ARDS.

Reactive oxygen species associated immunoregulation post influenza virus infection

An appropriate level of reactive oxygen species (ROS) is necessary for cell proliferation, signaling transduction, and apoptosis due to their highly reactive character. ROS are generated through multiple metabolic pathways under a fine-tuned control between oxidant and antioxidant signaling. A growing number of evidence has proved their highly relevant role in modulating inflammation during influenza virus infection. As a network of biological process for protecting organism from invasion of pathogens, immune system can react and fight back through either innate immune system or adaptive immune system, or both. Herein, we provide a review about the mechanisms of ROS generation when encounter influenza virus infection, and how the imbalanced level of ROS influences the replication of virus. We also summarize the pathways used by both the innate and adaptive immune system to sense and attack the invaded virus and abnormal levels of ROS. We further review the limitation of current strategies and discuss the direction of future work.

SHED-derived exosomes promote LPS-induced wound healing with less itching by stimulating macrophage autophagy

High-quality cutaneous wound healing is associated with rapid wound closure and a comfortable healing process. Currently, exosomes derived from mesenchymal stem cells displayed a prominent therapeutic effect on skin wound closure. But the therapeutic approaches for wound itching are very limited in clinical. Stem cells from human exfoliated deciduous teeth (SHED) may offer a unique exosome resource for cell-free therapeutics in potential clinical applications. Here, we investigated the common mechanisms underlying wound closure and unpleasant sensation of itching, focusing on the contribution of the SHED-derived exosome to immune response and wound itching during healing. The effects of SHED-derived exosomes on inflammatory wound healing were examined using lipopolysaccharide (LPS)-induced wounds in a mouse model. We found prolonged inflammation and distinct itch responses in skin wound tissue during LPS-induced wound healing. SHED-derived exosomes facilitated LPS-induced wound closure and relieved wound itching. Therefore, they are ideal for the treatment of wound healing. Macrophages in skin wound tissues are responsible for autophagy during wound healing. Macrophage autophagy also regulates cell proliferation, migration, and neuronal signal transduction in vitro. SHED-derived exosomes containing miR-1246 enhanced autophagy by regulating macrophage function through the AKT, ERK1/2, and STAT3 signaling pathways. Thus, SHED-derived exosomes promote wound healing with less itching in an LPS-induced wound model by stimulating macrophage autophagy, which has implications for the treatment of inflammatory wound healing.

Drug delivery for metabolism targeted cancer immunotherapy

Drug delivery vehicles have made a great impact on cancer immunotherapies in clinics and pre-clinical research. Notably, the science of delivery of cancer vaccines and immunotherapeutics, modulating immune cell functions has inspired development of several successful companies and clinical products. Interestingly, these drug delivery modalities not only modulate the function of immune cells (often quantified at the mRNA and protein levels), but also modulate the metabolism of these cells. Specifically, cancer immunotherapy often leads to activation of different immune cells such as dendritic cells, macrophages and T cells, which is driven by energy metabolism of these cells. Recently, there has been a great excitement about interventions that can directly modulate the energy metabolism of these immune cells and thus affect their function and in turn lead to a robust cancer immune response. Here we review few strategies that have been tested in clinic and pre-clinical research for generating effective metabolism-associated cancer therapies and immunotherapies.

Multistability in Macrophage Activation Pathways and Metabolic Implications

Macrophages are innate immune cells with a dynamic range of reversible activation states including the classical pro-inflammatory (M1) and alternative anti-inflammatory (M2) states. Deciphering how macrophages regulate their transition from one state to the other is key for a deeper understanding of inflammatory diseases and relevant therapies. Common regulatory motifs reported for macrophage transitions, such as positive or double-negative feedback loops, exhibit a switchlike behavior, suggesting the bistability of the system. In this review, we explore the evidence for multistability (including bistability) in macrophage activation pathways at four molecular levels. First, a decision-making module in signal transduction includes mutual inhibitory interactions between M1 (STAT1, NF-KB/p50-p65) and M2 (STAT3, NF-KB/p50-p50) signaling pathways. Second, a switchlike behavior at the gene expression level includes complex network motifs of transcription factors and miRNAs. Third, these changes impact metabolic gene expression, leading to switches in energy production, NADPH and ROS production, TCA cycle functionality, biosynthesis, and nitrogen metabolism. Fourth, metabolic changes are monitored by metabolic sensors coupled to AMPK and mTOR activity to provide stability by maintaining signals promoting M1 or M2 activation. In conclusion, we identify bistability hubs as promising therapeutic targets for reverting or blocking macrophage transitions through modulation of the metabolic environment.

Reactive Oxygen Species in Anticancer Immunity: A Double-Edged Sword

Reactive oxygen species (ROS) are critical mediators in many physiological processes including innate and adaptive immunity, making the modulation of ROS level a powerful strategy to augment anticancer immunity. However, current evidences suggest the necessity of a deeper understanding of their multiple roles, which may vary with their concentration, location and the immune microenvironment they are in. Here, we have reviewed the reported effects of ROS on macrophage polarization, immune checkpoint blocking (ICB) therapy, T cell activation and expansion, as well as the induction of immunogenic cell death. A majority of reports are indicating detrimental effects of ROS, but it is unadvisable to simply scavenge them because of their pleiotropic effects in most occasions (except in T cell activation and expansion where ROS are generally undesirable). Therefore, clinical success will need a clearer illustration of their multi-faced functions, as well as more advanced technologies to tune ROS level with high spatiotemporal control and species-specificity. With such progresses, the efficacy of current immunotherapies will be greatly improved by combining with ROS-targeted therapies.

Features of the Population of Mouse Peritoneal Macrophages Isolated after Stimulation with Concanavalin A and Thioglycolate

Murine peritoneal macrophages isolated from the lavage fluid after administration of thioglycolate and concanavalin A are presented by two populations of cells of different diameters. Polarization of macrophages into a proinflammatory (M1) phenotype is accompanied by an increase in number of small cells. Macrophages obtained after administration of thioglycolate demonstrate higher tendency to anti-inflammatory (M2) phenotype, while macrophages isolated after administration of concanavalin A are committed in the proinflammatory direction. Lactate level is increased in M1 macrophages in comparison with M2 cells, which indicates predominance of glycolytic metabolism. Macrophages obtained after administration of concanavalin A have reduced mitochondrial potential, which reflects a tendency to apoptosis. Autophagy activation and inhibition neutralize the differences in pro- and anti-inflammatory properties of polarized macrophages obtained after thioglycolate administration, but have less pronounced effect on macrophages obtained after administration concanavalin A. Autophagy inhibitor increases mitochondrial potential in non-polarized macrophages obtained after administration of concanavalin A. These results demonstrate divergent properties of macrophages obtained after administration of glycolate and concanavalin A due to the difference in the mechanisms of experimental peritonitis.

The Effects of Simulated Microgravity on Macrophage Phenotype

The effects of spaceflight, including prolonged exposure to microgravity, can have significant effects on the immune system and human health. Altered immune cell function can lead to adverse health events, though precisely how and to what extent a microgravity environment impacts these cells remains uncertain. Macrophages, a key immune cell, effect the inflammatory response as well as tissue remodeling and repair. Specifically, macrophage function can be dictated by phenotype that can exist between spectrums of M0 macrophage: the classically activated, pro-inflammatory M1, and the alternatively activated, pro-healing M2 phenotypes. This work assesses the effects of simulated microgravity via clinorotation on M0, M1, and M2 macrophage phenotypes. We focus on phenotypic, inflammatory, and angiogenic gene and protein expression. Our results show that across all three phenotypes, microgravity results in a decrease in TNF-α expression and an increase in IL-12 and VEGF expression. IL-10 was also significantly increased in M1 and M2, but not M0 macrophages. The phenotypic cytokine expression profiles observed may be related to specific gravisensitive signal transduction pathways previously implicated in microgravity regulation of macrophage gene and protein expression. Our results highlight the far-reaching effects that simulated microgravity has on macrophage function and provides insight into macrophage phenotypic function in microgravity.