Tumor-associated macrophages in colorectal cancer metastasis: molecular insights and translational perspectives.

Metastasis is the leading cause of high mortality in colorectal cancer (CRC), which is not only driven by changes occurring within the tumor cells, but is also influenced by the dynamic interaction between cancer cells and components in the tumor microenvironment (TME). Currently, the exploration of TME remodeling and its impact on CRC metastasis has attracted increasing attention owing to its potential to uncover novel therapeutic avenues. Noteworthy, emerging studies suggested that tumor-associated macrophages (TAMs) within the TME played important roles in CRC metastasis by secreting a variety of cytokines, chemokines, growth factors and proteases. Moreover, TAMs are often associated with poor prognosis and drug resistance, making them promising targets for CRC therapy. Given the prognostic and clinical value of TAMs, this review provides an updated overview on the origin, polarization and function of TAMs, and discusses the mechanisms by which TAMs promote the metastatic cascade of CRC. Potential TAM-targeting techniques for personalized theranostics of metastatic CRC are emphasized. Finally, future perspectives and challenges for translational applications of TAMs in CRC development and metastasis are proposed to help develop novel TAM-based strategies for CRC precision medicine and holistic healthcare.

[Prevention and treatment of lung cancer by regulating tumor-associated macrophages with traditional Chinese medicine].

Lung cancer is one of the common malignant tumors in the world, and its incidence and mortality is increasing year by year. Interactions between tumor cells and immune cells in the tumor microenvironment(TME) affect tumor proliferation, infiltration, and metastasis. Tumor-associated macrophages(TAMs) are prominent components of TME, and they have dual regulation effects on malignant progression of lung cancer. The number, activity, and function of M2 macrophages are related to the poor prognosis of lung cancer, and M2 macrophages participate in tumor angiogenesis and immune escape. It has been proved that traditional Chinese medicines(TCMs) and their active ingredients can enhance the antitumor effects, reduce the toxicity of chemotherapy and radiotherapy, and prolong the survival rates of patients with cancer. This paper summarized the role of TAMs in the lung cancer initiation and progression, explored the molecular mechanism of TCM in regulating the recruitment, polarization phenotype, activity, and expression of related factors and proteins of TAMs, and discussed related signal pathways in the prevention and treatment of lung cancer based on the TCM theory of "reinforcing healthy qi and eliminating pathogen". This paper is expected to provide new ideas for the immunotherapy of targeted TAMs.

A biomimetic nanoplatform for precise reprogramming of tumor-associated macrophages and NIR-II mediated antitumor immune activation.

The therapeutic effects of photothermal therapy (PTT) are dependent on the photothermal conversion efficiency of photothermal agents (PTAs) in tumors and the subsequent activation of the antitumor immune system. However, the insufficient tumor accumulation of current PTAs and the inevitable recruitment of tumor-associated macrophages (TAMs) could further compromise the antitumor activities of PTT. To address these issues, a biomimetic photothermal nanoplatform Au@Fe-PM is developed for the targeted remodeling of TAMs, which promotes the antitumor immunity of PTT. Au nanorods with second near-infrared (NIR-II) absorptions are fabricated to serve as PTAs to induce immunogenic cell death in tumor cells. The ferric hydroxide shell coated on Au nanorods can release iron ions to repolarize M2-like TAMs into the tumoricidal M1 phenotype via P38 and STAT1-mediated signaling pathways. Moreover, the surface decoration of platelet membranes endows biomimetic nanoplatform with enhanced tumor targeting ability for precise tumor ablation and TAM regulation. Consequently, Au@Fe-PM under NIR-II laser irradiation exhibits significantly higher inhibitory effects in a poor immunogenic 4T1 tumor-bearing mouse model with a 50% complete remission rate compared to conventional PTT (0%). By simultaneously reversing the immunosuppressive tumor microenvironment, this biomimetic nanoplatform offers a promising strategy for enhancing the antitumor efficacy of PTT. STATEMENT OF SIGNIFICANCE: The therapeutic effects of current photothermal therapy (PTT) are hindered by the insufficient tumor accumulation of conventional photothermal agents and the recruitment of immunosuppressive tumor-associated macrophages (TAMs) after PTT. Herein, we report a biomimetic iron-based second near-infrared (NIR-II) photothermal nanoplatform (Au@Fe-PM) for targeted TAMs reprogramming and NIR-II mediated anti-tumor immunity. Au@Fe-PM can actively target the tumor site with the help of surface-decorated platelet membranes. Meanwhile, iron ions would be released from Au@Fe-PM in acidic lysosomes to reprogram TAMs into tumoricidal M1-like macrophages, which promotes the antitumor responses elicited by NIR-II PTT, thereby contributing to remarkable tumor inhibitory effects, with 50% higher complete remission rate than that of conventional PTT.

7S,15R-Dihydroxy-16S,17S-epoxy-docosapentaenoic Acid Overcomes Chemoresistance of 5-Fluorouracil by Suppressing the Infiltration of Tumor-Associated Macrophages and Inhibiting the Activation of Cancer Stem Cells in a Colorectal Cancer Xenograft Model.

Although the tumor bulk is initially reduced by 5-fluorouracil (5-FU), chemoresistance developed due to prolonged chemotherapy in colorectal cancer (CRC). The enrichment of cancer stem cells (CSCs) and the infiltration of tumor-associated macrophages (TAMs) contribute to chemoresistance and poor outcomes. A docosahexaenoic acid derivative developed by our group, 7S,15R-dihydroxy-16S,17S-epoxy-docosapentaenoic acid (diHEP-DPA), exerts antitumor effects against TAMs infiltration and CSCs enrichment in our previous study. The current study aimed to investigate whether diHEP-DPA was able to overcome chemoresistance to 5-FU in CRCs, together with the potential synergistic mechanisms in a CT26-BALB/c mouse model. Our results suggested that although 5-FU inhibited tumor growth, 5-FU enriched CSCs via the WNT/ß-catenin signaling pathway, resulting in chemoresistance in CRCs. However, we revealed that 5-FU promoted the infiltration of TAMs via the NF-kB signaling pathway and improved epithelial-mesenchymal transition (EMT) via the signal transducer and activator of the transcription 3 (STAT3) signaling pathway; these traits were believed to contribute to CSC activation. Furthermore, supplementation with diHEP-DPA could overcome drug resistance by decreasing the CSCs, suppressing the infiltration of TAMs, and inhibiting EMT progression. Additionally, the combinatorial treatment of diHEP-DPA and 5-FU effectively enhanced phagocytosis by blocking the CD47/signal regulatory protein alpha (SIRPα) axis. These findings present that diHEP-DPA is a potential therapeutic supplement to improve drug outcomes and suppress chemoresistance associated with the current 5-FU-based therapies for colorectal cancer.

Targeted treatment of triple-negative-breast cancer through pH-triggered tumour associated macrophages using smart theranostic nanoformulations.

Triple-negative breast cancer (TNBC) represents 15-25 % of the new breast cancer cases diagnosed worldwide every year. TNBC is among the most aggressive and worst prognosis breast cancer, mainly because targeted therapies are not available. Herein, we developed a magnetic theranostic hybrid nanovehicle for targeted treatment of TNBC through pH-triggered tumour associated macrophages (TAMs) targeting. The lipid core of the nanovehicle was composed of a Carnaúba wax matrix that simultaneously incorporated iron oxide nanoparticles and doxorubicin (DOX) - a chemotherapeutic drug. These drug-loaded wax nanovehicles were modified with a combination of two functional and complementary molecules: (i) a mannose ligand (macrophage targeting) and (ii) an acid-sensitive sheddable polyethylene glycol (PEG) moiety (specificity). The TAMs targeting strategy relied on the mannose - mannose receptor recognition exclusively after acid-sensitive "shedding" of the PEG in the relatively low tumour microenvironment pH. The pH-induced targeting capability towards TAMs was confirmed in vitro in a J774A.1 macrophage cell line at different pH (7.4 and 6.5). Biocompatibility and efficacy of the final targeted formulations were demonstrated in vitro in the TNBC MDA-MB-231 cell line and in vivo in an M-Wnt tumour-bearing (TNBC) mouse model. A preferential accumulation of the DOX-loaded lipid nanovehicles in the tumours of M-Wnt-tumour bearing mice was observed, which resulted both on an efficient tumour growth inhibition and a significantly reduced off-target toxicity compared to free DOX. Additionally, the developed magnetic hybrid nanovehicles showed outstanding performances as T2-contrast agents in magnetic resonance imaging (r2 ≈ 400-600 mM-1·s-1) and as heat generating sources in magnetic hyperthermia (specific absorption rate, SAR ≈ 178 W·g-1Fe). These targeted magnetic hybrid nanovehicles emerge as a suitable theranostic option that responds to the urgent demand for more precise and personalized treatments, not only because they are able to offer localized imaging and therapeutic potential, but also because they allow to efficiently control the balance between safety and efficacy.

Prevention and treatment of lung cancer by regulating tumor-associated macrophages with traditional Chinese medicine / 中国中药杂志

Lung cancer is one of the common malignant tumors in the world, and its incidence and mortality is increasing year by year. Interactions between tumor cells and immune cells in the tumor microenvironment(TME) affect tumor proliferation, infiltration, and metastasis. Tumor-associated macrophages(TAMs) are prominent components of TME, and they have dual regulation effects on malignant progression of lung cancer. The number, activity, and function of M2 macrophages are related to the poor prognosis of lung cancer, and M2 macrophages participate in tumor angiogenesis and immune escape. It has been proved that traditional Chinese medicines(TCMs) and their active ingredients can enhance the antitumor effects, reduce the toxicity of chemotherapy and radiotherapy, and prolong the survival rates of patients with cancer. This paper summarized the role of TAMs in the lung cancer initiation and progression, explored the molecular mechanism of TCM in regulating the recruitment, polarization phenotype, activity, and expression of related factors and proteins of TAMs, and discussed related signal pathways in the prevention and treatment of lung cancer based on the TCM theory of "reinforcing healthy qi and eliminating pathogen". This paper is expected to provide new ideas for the immunotherapy of targeted TAMs.

A New Perspective on Cancer Therapy: Changing the Treaded Path?

During the last decade, we have persistently addressed the question, "how can the innate immune system be used as a therapeutic tool to eliminate cancer?" A cancerous tumor harbors innate immune cells such as macrophages, which are held in the tumor-promoting M2 state by tumor-cell-released cytokines. We have discovered that these tumor-associated macrophages (TAM) are repolarized into the nitric oxide (NO)-generating tumoricidal M1 state by the dietary agent curcumin (CC), which also causes recruitment of activated natural killer (NK) cells and cytotoxic T (Tc) cells into the tumor, thereby eliminating cancer cells as well as cancer stem cells. Indications are that this process may be NO-dependent. Intriguingly, the maximum blood concentration of CC in mice never exceeds nanomolar levels. Thus, our results submit that even low, transient levels of curcumin in vivo are enough to cause repolarization of the TAM and recruitment NK cells as well as Tc cells to eliminate the tumor. We have observed this phenomenon in two cancer models, glioblastoma and cervical cancer. Therefore, this approach may yield a general strategy to fight cancer. Our mechanistic studies have so far implicated induction of STAT-1 in this M2→M1 switch, but further studies are needed to understand the involvement of other factors such as the lipid metabolites resolvins in the CC-evoked anticancer pathways.

The role of tumor-associated macrophages in osteosarcoma progression - therapeutic implications.

BACKGROUND: Osteosarcoma (OS) is the most common primary malignant bone tumor. Compared with previous treatment modalities, such as amputation, more recent comprehensive treatment modalities based on neoadjuvant chemotherapy combined with limb salvage surgery have improved the survival rates of patients. Osteosarcoma treatment has, however, not further improved in recent years. Therefore, attention has shifted to the tumor microenvironment (TME) in which osteosarcoma cells are embedded. Therapeutic targets in the TME may be key to improving osteosarcoma treatment. Tumor-associated macrophages (TAMs) are the most common immune cells within the TME. TAMs in osteosarcoma may account for over 50% of the immune cells, and may play important roles in tumorigenesis, angiogenesis, immunosuppression, drug resistance and metastasis. Knowledge on the role of TAMs in the development, progression and treatment of osteosarcoma is gradually improving, although different or even opposing opinions still remain. CONCLUSIONS: TAMs may participate in the malignant progression of osteosarcoma through self-polarization, the promotion of blood vessel and lymphatic vessel formation, immunosuppression, and drug resistance. Besides, various immune checkpoint proteins expressed on the surface of TAMs, such as PD-1 and CD47, provide the possibility of the application of immune checkpoint inhibitors. Several clinical trials have been carried out and/or are in progress. Mifamotide and the immune checkpoint inhibitor Camrelizumab were both found to be effective in prolonging progression-free survival. Thus, TAMs may serve as attractive therapeutic targets. Targeting TAMs as a complementary therapy is expected to improve the prognosis of osteosarcoma. Further efforts may be made to identify potential beneficiaries of TAM-targeted therapies.

Modified Jian-pi-yang-zheng decoction inhibits gastric cancer progression via the macrophage immune checkpoint PI3Kγ.

Jian-pi-yang-zheng Decoction (JPYZ) is a traditional Chinese medicine that is used for the treatment of advanced gastric cancer, and it shows good efficacy in patients. A previous study indicated that JPYZ inhibited the progression of gastric cancer via the regulation of tumor-associated macrophages (TAMs), but the underlying molecular target of JPYZ regulation of TAMs has not been determined. The present study used modified-JPYZ (mJPYZ) to extend our investigation of gastric cancer. Our results showed that mJPYZ inhibited gastric cancer progression in vivo and in vitro. We found that mJPYZ decreased the activity of PI3-kinase γ (PI3Kγ) in TAMs, reduced the anti-inflammatory factor IL-10 and increased the expression of pro-inflammatory cytokines, such as TNF-α and IL-1ß, which ultimately promoted the conversion of TAMs from M2 to M1. Our findings also indicated that mJPYZ inhibited the growth and metastasis of gastric cancer by alleviating the unfavorable differentiation of TAMs via the PI3Kγ signaling cascades. In conclusion, the present findings indicated that mJPYZ inhibited gastric cancer cell EMT via PI3Kγ-dependent TAM reprogramming, which eventually suppressed gastric cancer growth and metastasis. Our study provides an underlying mechanism of a Chinese medicine in the treatment of gastric cancer via PI3Kγ in macrophages.

Extracts of Cordyceps sinensis inhibit breast cancer growth through promoting M1 macrophage polarization via NF-κB pathway activation.

ETHNOPHARMACOLOGICAL RELEVANCE: Cordyceps sinensis is a traditional Chinese medicine. It is widely reported that Cordyceps sinensis has inhibitory effect on tumor growth and immunoregulation effect on macrophages. However, the exact mechanism of Cordyceps sinensis on macrophage polarization in tumor progression is not known. AIM OF STUDY: We aimed to investigate the role of extracts of Cordyceps sinensis on macrophage polarization and its underlying mechanism in antitumor activity. MATERIALS AND METHODS: The 4T1 orthotopic xenograft mouse model and immunohistochemical staining were used to investigate the effect of Cordyceps sinensis on breast tumor and the change of the macrophages phenotype in the tumor, respectively. A 3D co-culture assay was used to confirm the activity in vitro. Measurement of cytokines and NO, quantitative real-time PCR and flow cytometry assays were used to investigate the effect of Cordyceps sinensis on the macrophage polarization in vitro. The mechanism of the effect of Cordyceps sinensis on macrophages was investigated by using western blot assays. RESULTS: In the orthotopic mouse tumor model, Cordyceps sinensis inhibited the 4T1 tumor growth in a dose dependent manner, and the immunohistochemical staining analysis showed that there is a positive correlation between tumor growth inhibition and macrophage M1-like polarized phenotype. The cytokines and NO measurement, quantitative real-time PCR assay and flow cytometry assays confirmed that Cordyceps sinensis could promote macrophage differentiation toward the M1 phenotype. The 3D co-culture assay and western blot assay showed that Cordyceps sinensis could inhibit tumor growth by promoting macrophage polarization and enhance its activity by activating the NF-κB signaling pathway. CONCLUSION: These findings suggest that Cordyceps sinensis could potently suppress TNBC progression by promoting M1 phenotypic differentiation of macrophages via activation NF-κB signaling pathway in tumor microenvironment.