Tumor-Associated Macrophages: Key Players in Triple-Negative Breast Cancer

LHPP expression in triple-negative breast cancer promotes tumor growth and metastasis by modulating the tumor microenvironment

Triple-negative breast cancer (TNBC) is a highly aggressive and metastatic form of breast cancer that lacks an effective targeted therapy. To identify new therapeutic targets, we investigated the phosphohistidine phosphatase, LHPP, which has been implicated in the development of several types of cancer. However, the full significance of LHPP in cancer progression remains unclear due to our limited understanding of its molecular mechanism. We found that levels of the LHPP phosphohistidine phosphatase were significantly increased in human breast cancer patients compared to normal adjacent tissues, with the highest levels in the TNBC subtype. When LHPP was knocked out in the MDA-MB-231 human TNBC cell line, cell proliferation, wound healing capacity, and invasion were significantly reduced. However, LHPP knockout in TNBC cells did not affect the phosphohistidine protein levels. Interestingly, LHPP knockout in MDA-MB-231 cells delayed tumor growth and reduced metastasis when orthotopically transplanted into mouse mammary glands. To investigate LHPP's role in breast cancer progression, we used next-generation sequencing and proximity-labeling proteomics, and found that LHPP regulates gene expression in chemokine-mediated signaling and actin cytoskeleton organization. Depletion of LHPP reduced the presence of tumor-infiltrating macrophages in mouse xenografts. Our results uncover a new tumor promoter role for LHPP phosphohistidine phosphatase in TNBC and suggest that targeting LHPP phosphatase could be a potential therapeutic strategy for TNBC.

Prognostic impact of tumor-associated neutrophils in breast cancer

OBJECTIVES

Neutrophils are the most common type of leukocyte in mammals and play an essential role in the innate immune system and anti-cancer responses. However, recent studies identified the presence of tumor-associated neutrophils (TANs) as a poor prognostic factor. The present study investigated whether relationships exist between TANs and the clinicopathological factors and genetic status of breast cancer.

METHODS

A total of 196 breast cancer patients with sufficient biopsy, breast-conserving surgery, or mastectomy specimens between 2014 and 2021 in Hokuto Hospital were included.

RESULTS

TANs were individually counted in the tumor stroma (TS) and tumor nest (TN). A higher density of TANs in both TS and TN correlated with tumor size (TS P = 0.010; TN P = 0.001), a high histological grade (TS P < 0.001; TN P < 0.001), the histological type (TS P = 0.009; TN P = 0.034), a high ratio of lymph node metastasis (TS P < 0.001; TN P < 0.001), an advanced stage of cancer (TS P < 0.001; TN P = 0.002), intrinsic subtypes (TS P < 0.001; TN P < 0.001), ERBB2 (TS P < 0.001; TN P < 0.001), MAP3K1 (TS P = 0.002; TN P = 0.023), and TP53 (TS P < 0.001; TN P < 0.001). A higher density of TANs in TS and TN also correlated with shorter disease-free survival and overall survival (P < 0.001).

CONCLUSION

The present results suggest that a higher density of TANs correlates with unfavorable prognostic factors in breast cancer. Further research on clinicopathological and genetic factors associated with TANs in breast cancer is needed.

Targeting cancer stem cell plasticity in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype with limited treatment options. Cancer stem cells (CSCs) are thought to play a crucial role in TNBC progression and resistance to therapy. CSCs are a small subpopulation of cells within tumors that possess self-renewal and differentiation capabilities and are responsible for tumor initiation, maintenance, and metastasis. CSCs exhibit plasticity, allowing them to switch between states and adapt to changing microenvironments. Targeting CSC plasticity has emerged as a promising strategy for TNBC treatment. This review summarizes recent advances in understanding the molecular mechanisms underlying CSC plasticity in TNBC and discusses potential therapeutic approaches targeting CSC plasticity.

The Streptococcus virulence protein PepO triggers anti-tumor immune responses by reprograming tumor-associated macrophages in a mouse triple negative breast cancer model

BACKGROUND

The efficacy of current surgery and chemotherapy for triple negative breast cancer (TNBC) is limited due to heterogenous and immunosuppressive tumor microenvironment (TME). Tumor associated macrophages (TAMs), which are regarded as an M2 tumor-promoting phenotype, are crucial in the development of the immunosuppressive TME. Targeting TAM reprograming is a promising strategy in anti-tumor therapy since reprogramming techniques provide the opportunity to actively enhance the antitumor immunological activity of TAM in addition to eliminating their tumor-supportive roles, which is rarely applied in TNBC clinically. However, how to drive M2 macrophages reprogramming into M1 with high potency remains a challenge and the molecular mechanisms how M2 macrophages polarized into M1 are poorly understood. Here, we identified a new immunoregulatory molecular PepO that was served as an immunoregulatory molecule governed the transformation of tumor-promoting M2 to tumor-inhibitory M1 cells and represented an effective anti-tumor property.

RESULTS

At the present study, we identified a new immunoregulatory molecular PepO, as a harmless immunoregulatory molecule, governed the transformation of tumor-promoting M2 to tumor-inhibitory M1 cells efficiently. PepO-primed M2 macrophages decreased the expression of tumor-supportive molecules like Arg-1, Tgfb, Vegfa and IL-10, and increased the expression of iNOS, Cxcl9, Cxcl10, TNF-α and IL-6 to inhibit TNBC growth. Moreover, PepO enhanced the functions of macrophages related to cell killing, phagocytosis and nitric oxide biosynthetic process, thereby inhibiting the development of tumors in vivo and in vitro. Mechanistically, PepO reprogramed TAMs toward M1 by activating PI3K-AKT-mTOR pathway via TLR4 and suppressed the function of M2 by inhibiting JAK2-STAT3 pathway via TLR2. The PI3K inhibitor LY294002 abrogated the role of PepO in switching M2 macrophages into M1 and in inhibiting TNBC growth in vivo. And PepO failed to govern the M2 macrophages to reprogram into M1 macrophages and inhibit TNBC when TLR2 or TLR4 was deficient. Moreover, PepO enhanced the antitumor activity of doxorubicin and the combination exerted a synergistic effect on TNBC suppression.

CONCLUSIONS

Our research identified a possible macrophage-based TNBC immunotherapeutic approach and suggested a novel anticancer immunoregulatory molecular called PepO.

Unveiling the Immune Microenvironment's Role in Breast Cancer: A Glimpse into Promising Frontiers

Breast cancer (BC), one of the most widespread and devastating diseases affecting women worldwide, presents a significant public health challenge. This review explores the emerging frontiers of research focused on deciphering the intricate interplay between BC cells and the immune microenvironment. Understanding the role of the immune system in BC is critical as it holds promise for novel therapeutic approaches and precision medicine strategies. This review delves into the current literature regarding the immune microenvironment's contribution to BC initiation, progression, and metastasis. It examines the complex mechanisms by which BC cells interact with various immune cell populations, including tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs). Furthermore, this review highlights the impact of immune-related factors, such as cytokines and immune checkpoint molecules. Additionally, this comprehensive analysis sheds light on the potential biomarkers associated with the immune response in BC, enabling early diagnosis and prognostic assessment. The therapeutic implications of targeting the immune microenvironment are also explored, encompassing immunotherapeutic strategies and combination therapies to enhance treatment efficacy. The significance of this review lies in its potential to pave the way for novel therapeutic interventions, providing clinicians and researchers with essential knowledge to design targeted and personalized treatment regimens for BC patients.

The NF-κB Transcriptional Network Is a High-Dose Vitamin C-Targetable Vulnerability in Breast Cancer

Breast cancer (BC) is the most common cancer type among women with a distinct clinical presentation, but the survival rate remains moderate despite advances in multimodal therapy. Consequently, a deeper understanding of the molecular etiology is required for the development of more effective treatments for BC. The relationship between inflammation and tumorigenesis is well established, and the activation of the pro-inflammatory transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is frequently identified in BC. Constitutive NF-κB activation is linked to cell survival, metastasis, proliferation, and hormonal, chemo-, and radiotherapy resistance. Moreover, the crosstalk between NF-κB and other transcription factors is well documented. It is reported that vitamin C plays a key role in preventing and treating a number of pathological conditions, including cancer, when administered at remarkably high doses. Indeed, vitamin C can regulate the activation of NF-κB by inhibiting specific NF-κB-dependent genes and multiple stimuli. In this review, we examine the various NF-κB impacts on BC development. We also provide some insight into how the NF-κB network may be targeted as a potential vulnerability by using natural pro-oxidant therapies such as vitamin C.

Tumor Suppressive Role of MicroRNAs in Triple Negative Breast Cancer

Triple-negative breast cancers are highly aggressive, a heterogeneous form of breast cancer with a high re-occurrence rate that further lacks an efficient treatment strategy and prognostic marker. The tumor microenvironment of the disease comprises cancer-associated fibroblasts, cancer stem cells, immunological molecules, epithelial-mesenchymal transition, and a metastatic microenvironment that contributes to disease progression and metastasis to distant sites. Emerging evidence indicated that miRNA clusters would be of clinical utility as they exert an oncogenic or tumor suppressor role in TNBC. The present review article aims to highlight the therapeutic significance of miRNA in targeting the above-mentioned signaling cascades and modulating the intracellular crosstalk in the tumor microenvironment of TNBC. Prognostic implications of miRNAs to depict disease-free survival, distant metastasis-free survival, relapse-free survival, and overall survival outcome were also unveiled.

The tumor microenvironment and triple-negative breast cancer aggressiveness: shedding light on mechanisms and targeting

INTRODUCTION

In contrast to other breast cancer subtypes, there are currently limited options of targeted therapies for triple-negative breast cancer (TNBC). Immense research has demonstrated that not only cancer cells but also stromal cells and immune cells in the tumor microenvironment (TME) play significant roles in the progression of TNBC. It is thus critical to understand the components of the TME of TNBC and the interactions between the various cell populations.

AREAS COVERED

The components of the TME of TNBC identified by single-cell technologies are reviewed. Furthermore, the molecular interactions between the cells and the potential therapeutic targets contributing to the progression of TNBC are discussed.

EXPERT OPINION

Single-cell omics studies have contributed to the classification of cells in the TME and the identification of important cell types involved in the progression and the treatment of the tumor. The interactions between cancer cells and stromal cells/immune cells in the TME have led to the discovery of potential therapeutic targets. Experimental data with spatial and temporal resolution will further boost the understanding of the TME of TNBC.

Crosstalk between Depression and Breast Cancer via Hepatic Epoxide Metabolism: A Central Comorbidity Mechanism

Breast cancer (BC) is a serious global challenge, and depression is one of the risk factors and comorbidities of BC. Recently, the research on the comorbidity of BC and depression has focused on the dysfunction of the hypothalamic–pituitary–adrenal axis and the persistent stimulation of the inflammatory response. However, the further mechanisms for comorbidity remain unclear. Epoxide metabolism has been shown to have a regulatory function in the comorbid mechanism with scattered reports. Hence, this article reviews the role of epoxide metabolism in depression and BC. The comprehensive review discloses the imbalance in epoxide metabolism and its downstream effect shared by BC and depression, including overexpression of inflammation, upregulation of toxic diols, and disturbed lipid metabolism. These downstream effects are mainly involved in the construction of the breast malignancy microenvironment through liver regulation. This finding provides new clues on the mechanism of BC and depression comorbidity, suggesting in particular a potential relationship between the liver and BC, and provides potential evidence of comorbidity for subsequent studies on the pathological mechanism.

Efficacy and safety of taxanes combined with chemotherapy drugs in advanced triple negative breast cancer: A meta-analysis of 26 randomized controlled trials

Background

Researchers have demonstrated that the combined use of taxanes and chemotherapy drugs, especially paclitaxel-based treatment, appeared to clinically benefit on advanced triple negative breast cancer (TNBC). This meta-analysis aims to obtain the existent evidence on efficacy and safety for taxanes-based combination therapy to treat advanced TNBC.

Methods

From 1991 to June 2022, seven databases (PubMed, Web of Science, Cochrane Library, Embase VIP, Wanfang, and CNKI databases) were comprehensively searched with no restricted language and region. The included randomized controlled trials (RCTs) compared taxanes-based combination therapy versus taxanes or other chemotherapy drugs. Statistical analysis was conducted using random-effect model, and the quality of RCTs was assessed using the tool of Cochrane Collaboration risk of bias.

Results

Twenty-six RCTs with a total of 8,236 advanced TNBC patients were included. Compared with taxanes monotherapy, taxanes-based combination therapy significantly prolonged progression-free survival (HR=0.79, 95%CI=0.74–0.83, I²= 0.0%, p=0.000) and overall survival (HR=0.88, 95%CI=0.82–0.94, I²= 9.3%, p=0.000) and increased the risk of vomiting (RR=1.26, 95%CI=1.07–1.48) and diarrhea (RR=1.82, 95%CI=1.22–2.70, I²= 90.3%, p=0.003). No statistical differences were observed in complete response rate (CRR), objective response rate (ORR), disease control rate (DCR), and progressive disease (PD) indexes (CRR: RR=1.38, 95%CI=0.96–1.99; ORR: RR=1.20, 95%CI=0.73–1.98; DCR: RR=1.09, 95%CI=1.00–1.19; PD: RR=0.70, 95%CI=0.47–1.04). Compared with other chemotherapy drugs, taxanes plus other chemotherapy drugs significantly reduced the incidence of vomiting (RR=0.60, 95%CI=0.44–0.84, I²= 12.3%, p=0.002) and neutropenia (RR=0.58, 95%CI=0.35–0.96, I²= 73.0%, p=0.036) during the treatment period.

Conclusions

Taxanes-based combination therapy is evidently effective and well-tolerated in advanced TNBC, indicating that it might be a recommended option for treating advanced TNBC patients to some extent.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022337802.

Targeting tumor-associated macrophages for cancer treatment

Tumor-associated macrophages (TAMs) are abundant, nearly accounting for 30–50% of stromal cells in the tumor microenvironment. TAMs exhibit an immunosuppressive M2-like phenotype in advanced cancer, which plays a crucial role in tumor growth, invasion and migration, angiogenesis and immunosuppression. Consequently, the TAM-targeting therapies are particularly of significance in anti-cancer strategies. The application of TAMs as anti-cancer targets is expected to break through traditional tumor-associated therapies and achieves favorable clinical effect. However, the heterogeneity of TAMs makes the strategy of targeting TAMs variable and uncertain. Discovering the subset specificity of TAMs might be a future option for targeting TAMs therapy. Herein, the review focuses on highlighting the different modalities to modulate TAM’s functions, including promoting the phagocytosis of TAMs, TAMs depletion, blocking TAMs recruitment, TAMs reprogramming and suppressing immunosuppressive tumor microenvironment. We also discuss about several ways to improve the efficacy of TAM-targeting therapy from the perspective of combination therapy and specificity of TAMs subgroups.

Targeting tumor-associated macrophages for cancer treatment

Tumor-associated macrophages (TAMs) are abundant, nearly accounting for 30-50% of stromal cells in the tumor microenvironment. TAMs exhibit an immunosuppressive M2-like phenotype in advanced cancer, which plays a crucial role in tumor growth, invasion and migration, angiogenesis and immunosuppression. Consequently, the TAM-targeting therapies are particularly of significance in anti-cancer strategies. The application of TAMs as anti-cancer targets is expected to break through traditional tumor-associated therapies and achieves favorable clinical effect. However, the heterogeneity of TAMs makes the strategy of targeting TAMs variable and uncertain. Discovering the subset specificity of TAMs might be a future option for targeting TAMs therapy. Herein, the review focuses on highlighting the different modalities to modulate TAM's functions, including promoting the phagocytosis of TAMs, TAMs depletion, blocking TAMs recruitment, TAMs reprogramming and suppressing immunosuppressive tumor microenvironment. We also discuss about several ways to improve the efficacy of TAM-targeting therapy from the perspective of combination therapy and specificity of TAMs subgroups.

Multimodal imaging and photothermal synergistic immunotherapy of retinoblastoma with tuftsin-loaded carbonized MOF nanoparticles

Retinoblastoma (Rb) represents 3% of all childhood malignancies and seriously endangers children's lives and quality of life. Early diagnosis and treatment can save children's vision as much as possible. Multifunctional nanoparticles have become a research hotspot in recent years and are expected to realize the integration of early diagnosis and early treatment. Therefore, we report a nanoparticle with dual-mode imaging, photothermal therapy, and immune activation: carbonized MOF nanoparticles (CM NPs) loaded with the immune polypeptide tuftsin (CMT NPs). The dual-mode imaging ability, antitumor effect, and macrophage immunity activation ability of these nanoparticles combined with laser irradiation were studied. The biosafety of CMT NPs was detected. The multifunctional magnetic nanoparticles enhanced photoacoustic (PA) and magnetic resonance (MR) imaging in vivo and in vitro, facilitating diagnosis and efficacy evaluation. The combined effect of CMT NPs and laser irradiation was recorded and verified. Through the accumulation of magnetic field nanoparticles in tumors, the photothermal conversion of nanoparticles under laser irradiation led directly to tumor apoptosis/necrosis, and the release of tuftsin induced macrophage M1-type activation, resulting in antitumor immune effects. Enhanced PA/MR imaging CMT NPs have great potential in dual-mode image-guided laser/immune cotherapy. The nanoparticles have high biosafety and have potential in cancer treatment.