Reprogramming Of Tumor-associated Macrophages Research Articles

Novel Role of Chidamide in Tumor-Associated Macrophages Reprogramming and Immunotherapy Enhancement through RNA Splicing

Novel Role of Chidamide in Tumor-Associated Macrophages Reprogramming and Immunotherapy Enhancement through RNA Splicing

Dynamic reciprocal interactions between activated T cells and tumor associated macrophages drive macrophage reprogramming and proinflammatory T cell migration within prostate tumor models

Tumor-associated macrophages (TAMs) have been implicated as a tumor microenvironment (TME) cell population, which may be playing a vital role in the inhibition of effective T cell responses in the prostate TME. In this manuscript, we leverage a novel microscale cell culture platform, known as Stacks, to investigate mono-, co-, and tri-culture TME models comprised of prostate tumor cell lines, primary macrophages, and autologous T cells from patients with prostate cancer. Through multiplexed analysis of these multi-cellular prostate tumor models, we capture a dynamic interaction between primary TAMs and activated T cells that resulted in reciprocal proinflammatory activation of both cell populations upon interaction. These findings suggest that activated T cells are capable of reprogramming immunosuppressive TAMs in the context of prostate tumor models and that TAM reprogramming may play a key supportive role in restoring proinflammatory T cell tumor responses in the prostate TME.

Thymosin α1 reverses oncolytic adenovirus-induced M2 polarization of macrophages to improve antitumor immunity and therapeutic efficacy

Although oncolytic adenoviruses are widely studied for their direct oncolytic activity and immunomodulatory role in cancer immunotherapy, the immunosuppressive feedback loop induced by oncolytic adenoviruses remains to be studied. Here, we demonstrate that type V adenovirus (ADV) induces the polarization of tumor-associated macrophages (TAMs) to the M2 phenotype and increases the infiltration of regulatory Tcells (Tregs) in the tumor microenvironment (TME). By selectively compensating for these deficiencies, thymosin alpha 1 (Tα1) reprograms "M2-like" TAMs toward an antitumoral phenotype, thereby reprogramming the TME into a state more beneficial for antitumor immunity. Moreover, ADVTα1 is constructed by harnessing the merits of all the components for the aforementioned combinatorial therapy. Both exogenously supplied and adenovirus-produced Tα1 orchestrate TAM reprogramming and enhance the antitumor efficacy of ADV via CD8+ Tcells, showing promising prospects for clinical translation. Our findings provide inspiration for improving oncolytic adenovirus combination therapy and designing oncolytic engineered adenoviruses.

Reprogramming tumor-associated macrophages using exosomes from M1 macrophages

Macrophages, abundant in tumors, are classified as M1 or M2 types with M2 dominating the tumor microenvironment. Shifting macrophages from M2 to M1 using exosomes is a promising intervention. The properties of exosomes depend on their source cells. M1-exosomes are expected to polarize macrophages towards M1 phenotype. We compared M1-exosomes and M0-exosomes' effects on M2 macrophage polarization.The RAW264.7 cells were cultured and one group of them was exposed to LPS. The serum-free medium was collected and exosomes were extracted. Exosomes were analyzed by scanning and transmission electron microscopy, dynamic light scattering and Western blot. Subsequently, M1 or M0 exosomes were applied to M2 macrophages induced by IL4. The macrophages polarization, including M1 and M2 genes and surface markers expression, cytokines secretion, and phagocytosis ability were evaluated.It was demonstrated that M1-exosomes induced macrophage polarization toward the M1 phenotype, characterized by an upregulation of M1-specific markers and a downregulation of M2 markers. Furthermore, the secretion of TNF-α was increased, while the secretion of IL-10 was decreased. The phagocytosis ability of M1-exosome-treated macrophages was also augmented.This research suggested that M1-exosomes might be promising candidates for modulating immune response in situations marked by an overabundance of M2 polarization, like in cancer.

Eganelisib combined with immune checkpoint inhibitor therapy and chemotherapy in frontline metastatic triple-negative breast cancer triggers macrophage reprogramming, immune activation and extracellular matrix reorganization in the tumor microenvironment

BackgroundTriple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with a poor prognosis particularly in the metastatic setting. Treatments with anti-programmed cell death protein-1/programmed death-ligand 1 (PD-L1) immune...

Surface Molecularly Engineered Mitochondria Conduct Immunophenotype Repolarization of Tumor-Associated Macrophages to Potentiate Cancer Immunotherapy.

Reprogramming tumor-associated macrophages (TAMs) to an inflammatory phenotype effectively increases the potential of immune checkpoint blockade (ICB) therapy. Artificial mitochondrial transplantation, an emerging and safe strategy, has made brilliant achievements in regulating the function of recipient cells in preclinic and clinic, but its performance in reprogramming the immunophenotype of TAMs has not been reported. Here, the metabolism of M2 TAMs is proposed resetting from oxidative phosphorylation (OXPHOS) to glycolysis for polarizing M1 TAMs through targeted transplantation of mannosylated mitochondria (mPEI/M1mt). Mitochondria isolated from M1 macrophages are coated with mannosylated polyethyleneimine (mPEI) through electrostatic interaction to form mPEI/M1mt, which can be targeted uptake by M2 macrophages expressed a high level of mannose receptors. Mechanistically, mPEI/M1mt accelerates phosphorylation of NF-κB p65, MAPK p38 and JNK by glycolysis-mediated elevation of intracellular ROS, thus prompting M1 macrophage polarization. In vivo, the transplantation of mPEI/M1mt excellently potentiates therapeutic effects of anti-PD-L1 by resetting an antitumor proinflammatory tumor microenvironmentand stimulating CD8 and CD4 T cells dependent immune response. Altogether, this work provides a novel platform for improving cancer immunotherapy, meanwhile, broadens the scope of mitochondrial transplantation technology in clinics in the future.

Reprogramming Tumor-Associated Macrophages with a Se-Based Core-Satellite Nanoassembly to Enhance Cancer Immunotherapy.

Tumor-associated macrophages (TAMs), as the most prevalent immune cells in the tumor microenvironment, play a pivotal role in promoting tumor development through various signaling pathways. Herein, we have engineered a Se@ZIF-8 core-satellite nanoassembly to reprogram TAMs, thereby enhancing immunotherapy outcomes. When the nanoassembly reaches the tumor tissue, selenium nanoparticles and Zn2+ are released in response to the acidic tumor microenvironment, resulting in a collaborative effort to promote the production of reactive oxygen species (ROS). The generated ROS, in turn, activate the nuclear factor κB (NF-κB) signaling pathway, driving the repolarization of TAMs from M2-type to M1-type, effectively eliminating cancer cells. Moreover, the nanoassembly can induce the immunogenic death of cancer cells through excess ROS to expose calreticulin and boost macrophage phagocytosis. The Se@ZIF-8 core-satellite nanoassembly provides a potential paradigm for cancer immunotherapy by reversing the immunosuppressive microenvironment.

Photosensitive and dual-targeted chromium nanoparticle delivering small interfering RNA YTHDF1 for molecular-targeted immunotherapy in liver cancer

Tumor-associated macrophages (TAMs) are a promising target for cancer immunotherapy, but delivering therapeutic agents to TAMs within the tumor microenvironment (TME) is challenging. In this study, a photosensitive, dual-targeting nanoparticle system (M.RGD@Cr-CTS-siYTHDF1 NPs) was developed. The structure includes a shell of DSPE-modified RGD peptides targeting integrin receptors on tumor cells and carboxymethyl mannose targeting CD206 receptors on macrophages, with a core of chitosan adsorbing m6A reading protein YTHDF1 siRNA and chromium nanoparticles (Cr NPs). The approach is specifically designed to target TAM and cancer cells, utilizing the photothermal effect of Cr NPs to disrupt the TME and deliver siYTHDF1 to TAM. In experiments with tumor-bearing mice, M.RGD@Cr-CTS-siYTHDF1 NPs, when exposed to laser irradiation, effectively killed tumor cells, disrupted the TME, delivered siYTHDF1 to TAMs, silenced the YTHDF1 gene, and shifted the STAT3-STAT1 equilibrium by reducing STAT3 and enhancing STAT1 expression. This reprogramming of TAMs towards an anti-tumor phenotype led to a pro-immunogenic TME state. The strategy also suppressed immunosuppressive IL-10 production, increased expression of immunostimulatory factors (IL-12 and IFN-γ), boosted CD8 + T cell infiltration and M1-type TAMs, and reduced Tregs and M2-type TAMs within the TME. In conclusion, the dual-targeting M.RGD@Cr-CTS-siYTHDF1 NPs, integrating dual-targeting capabilities with photothermal therapy (PTT) and RNA interference, offer a promising approach for molecular targeted cancer immunotherapy with potential for clinical application.Graphical

Biointerface-Engineered Hybrid Nanovesicles for Targeted Reprogramming of Tumor Microenvironment.

The tumor microenvironment (TME) of typical tumor types such as triple-negative breast cancer is featured by hypoxia and immunosuppression with abundant tumor-associated macrophages (TAMs), which also emerge as potential therapeutic targets for antitumor therapy. M1-like macrophage-derived exosomes (M1-Exos) have emerged as a promising tumor therapeutic candidate for their tumor-targeting and macrophage-polarization capabilities. However, the limited drug-loading efficiency and stability of M1-Exos have hindered their effectiveness in antitumor applications. Here, a hybrid nanovesicle is developed by integrating M1-Exos with AS1411 aptamer-conjugated liposomes (AApt-Lips), termed M1E/AALs. The obtained M1E/AALs are loaded withperfluorotributylamine (PFTBA)and IR780, as P-I, to construct P-I@M1E/AALs for reprogramming TME by alleviating tumor hypoxia and engineering TAMs. P-I@M1E/AAL-mediated tumor therapy enhances the in situ generation of reactive oxygen species, repolarizes TAMs toward an antitumor phenotype, and promotes the infiltration of T lymphocytes. The synergistic antitumor therapy based on P-I@M1E/AALs significantly suppresses tumor growth and prolongs the survival of 4T1-tumor-bearing mice. By integrating multiple treatment modalities, P-I@M1E/AAL nanoplatform demonstrates a promising therapeutic approach for overcoming hypoxic and immunosuppressive TME by targeted TAM reprogramming and enhanced tumor photodynamic immunotherapy. This study highlights an innovative TAM-engineering hybrid nanovesicle platform for the treatment of tumors characterized by hypoxic and immunosuppressive TME.

TREM2 deficiency reprograms intestinal macrophages and microbiota to enhance anti-PD-1 tumor immunotherapy.

The gut microbiota and tumor-associated macrophages (TAMs) affect tumor responses to anti-programmed cell death protein 1 (PD-1) immune checkpoint blockade. Reprogramming TAM by either blocking or deleting the macrophage receptor triggering receptor on myeloid cells 2 (TREM2) attenuates tumor growth, and lack of functional TREM2 enhances tumor elimination by anti-PD-1. Here, we found that anti-PD-1 treatment combined with TREM2 deficiency in mice induces proinflammatory programs in intestinal macrophages and a concomitant expansion of Ruminococcus gnavus in the gut microbiota. Gavage of wild-type mice with R. gnavus enhanced anti-PD-1-mediated tumor elimination, recapitulating the effect occurring in the absence of TREM2. A proinflammatory intestinal environment coincided with expansion, increased circulation, and migration of TNF-producing CD4+ T cells to the tumor bed. Thus, TREM2 remotely controls anti-PD-1 immune checkpoint blockade through modulation of the intestinal immune environment and microbiota, with R. gnavus emerging as a potential probiotic agent for increasing responsiveness to anti-PD-1.

Reprogramming tumor-associated macrophages and inhibiting tumor neovascularization by targeting MANF–HSF1–HSP70-1 pathway: An effective treatment for hepatocellular carcinoma

In advanced hepatocellular carcinoma (HCC) tissues, M2-like tumor-associated macrophages (TAMs) are in the majority and promotes HCC progression. Contrary to the pro-tumor effect of M2-like TAMs, M1-like TAMs account for a small proportion and have anti-tumor effects. Since TAMs can switch from one type to another, reprogramming TAMs may be an important treatment for HCC therapy. However, the mechanisms of phenotypic switch and reprogramming TAMs are still obscure. In this study, we analyzed differential genes in normal macrophages and TAMs, and found that loss of MANF in TAMs accompanied by high levels of downstream genes negatively regulated by MANF. MANF reprogrammed TAMs into M1 phenotype. Meanwhile, loss of MANF promoted HCC progression in HCC patients and mice HCC model, especially tumor neovascularization. Additionally, macrophages with MANF supplement suppressed HCC progression in mice, suggesting MANF supplement in macrophage was an effective treatment for HCC. Mechanistically, MANF enhanced the HSF1–HSP70-1 interaction, restricted HSF1 in the cytoplasm of macrophages, and decreased both mRNA and protein levels of HSP70-1, which in turn led to reprogramming TAMs, and suppressing neovascularization of HCC. Our study contributes to the exploration the mechanism of TAMs reprogramming, which may provide insights for future therapeutic exploitation of HCC neovascularization.

Reprogramming Tumor-Associated Macrophage Using Nanocarriers: New Perspectives to Halt Cancer Progression.

Cancer remains a significant challenge for public healthcare systems worldwide. Within the realm of cancer treatment, considerable attention is focused on understanding the tumor microenvironment (TME)-the complex network of non-cancerous elements surrounding the tumor. Among the cells in TME, tumor-associated macrophages (TAMs) play a central role, traditionally categorized as pro-inflammatory M1 macrophages or anti-inflammatory M2 macrophages. Within the TME, M2-like TAMs can create a protective environment conducive to tumor growth and progression. These TAMs secrete a range of factors and molecules that facilitate tumor angiogenesis, increased vascular permeability, chemoresistance, and metastasis. In response to this challenge, efforts are underway to develop adjuvant therapy options aimed at reprogramming TAMs from the M2 to the anti-tumor M1 phenotype. Such reprogramming holds promise for suppressing tumor growth, alleviating chemoresistance, and impeding metastasis. Nanotechnology has enabled the development of nanoformulations that may soon offer healthcare providers the tools to achieve targeted drug delivery, controlled drug release within the TME for TAM reprogramming and reduce drug-related adverse events. In this review, we have synthesized the latest data on TAM polarization in response to TME factors, highlighted the pathological effects of TAMs, and provided insights into existing nanotechnologies aimed at TAM reprogramming and depletion.

Abstract 1356: The VISTA blocking antibody HMBD-002 promotes type-I interferon signaling and drives anti-tumor responses through macrophage reprograming and cytotoxic CD8+ T cell activation

Abstract VISTA, a predominantly myeloid immune checkpoint, promotes an immunosuppressive tumor microenvironment and has been associated with resistance to approved checkpoint therapies. While blockade of VISTA with antibodies has shown anti-tumor efficacy in preclinical models, the biological mechanisms that underlie this effect remain poorly understood. To investigate the mechanistic basis of anti-tumor responses, we performed single-cell RNA sequencing of tumor infiltrating leukocytes from the cell-derived murine colon carcinoma xenograft model, CT26, which is known to be sensitive to VISTA blockade. We used HMBD-002, a uniquely blocking but non-depleting clinical-stage IgG4 anti-VISTA antibody, to identify the key immune cells and pathways impacted by VISTA blockade in the absence of Fc-mediated cell depletion. The translatability of these findings was validated in a human PBMC mixed leukocyte reaction assay. Subsequently, targeted depletion or inhibition of the identified immune populations and pathways was performed to confirm their contribution to the anti-tumor efficacy of HMBD-002.The blockade of VISTA by HMBD-002 significantly increased CD8+ T cells in the CT26 tumors, promoting an activated cytotoxic Tc1 program without inducing exhaustion. Concurrently, a substantial increase in proinflammatory M1 tumor-associated macrophages (TAMs) was noted within treated tumors, while other immune cell populations remained unaffected. Among the signaling pathways, the type-I interferon (IFN) response exhibited a significant upregulation, particularly in TAMs, indicating a type-I IFN-driven M1 reprogramming by HMBD-002. Validation experiments further demonstrated that the depletion of TAMs or CD8+ T cells, but not CD4+ T cells, abrogated the efficacy of HMBD-002. Moreover, blocking the type-I IFN signaling effectively impeded HMBD-002-induced TAM reprogramming and subsequent anti-tumor efficacy, thus confirming the pivotal roles of CD8+ T cells, TAMs, and type-I IFN signaling in driving the anti-tumor response to VISTA blockade. In conclusion, VISTA blockade with HMBD-002 promotes an anti-tumor response by type-I IFN mediated reprogramming of TAMs and activation of cytotoxic CD8+ T cells. Citation Format: Bhushan Dharmadhikari, Olga Zharkova, Dipti Thakkar, Roberto Tirado-Magallanes, Konrad Paszkiewicz, Piers J. Ingram, Jerome D. Boyd-Kirkup. The VISTA blocking antibody HMBD-002 promotes type-I interferon signaling and drives anti-tumor responses through macrophage reprograming and cytotoxic CD8+ T cell activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1356.

Abstract 715: Nanomedicines loaded with TLR agonists and inhibitors of immunosuppression to reprogram the tumor microenvironment

Abstract The stroma of solid tumors is populated by myeloid cells, which mostly represent macrophages. Tumor-associated macrophages (TAMs), strongly influenced by cancer cell-derived factors, are key drivers of immunosuppression and support tumor growth and spread to distant sites. Increasing evidence demonstrates their ability to hamper cancer patients' response to most treatments currently applied in the clinic, including immunotherapy. Therefore, strategies to counteract negative effects of TAMs are nowadays gaining momentum at preclinical, translational, and clinical levels. Here, we present the development and evaluation of nanoparticles (NPs) loaded with TLR agonists and/or inhibitors of immunosuppressive pathways to reprogram TAMs and the tumor microenvironment (TME) to unleash an effective immune response to fight against the tumor. Firstly, we have evaluated in vitro the ability of poly(I:C) and/or R848, agonists of TLR3 and TLR7/8 respectively, to reprogram TAMs into antitumor effector cells, and also the efficacy of Stattic and/or Galunisertib, inhibitors of STAT3 and TGF-β pathways respectively, to inhibit immunosuppression by cancer cells and/or TAMs. The best combinations of these drugs were encapsulated in nanoemulsions or polymeric nanocapsules for improved TAM-targeting and pharmacokinetics in vivo. These NPs were characterized for their physicochemical properties and also tested in vitro using primary human macrophages. For in vivo evaluation, subcutaneous and orthotopic murine models of lung cancer (CMT167) were used, showing antitumoral efficacy and TME reprogramming as evaluated by FACS, RNA analysis and multiplex immunofluorescence. Protamine-NCs-loaded with poly(I:C)+R848 and coated with an additional layer of hyaluronic acid functionalized with mannose were used to target the CD206 receptors, showing antitumoral efficacy mediated by TAM reprogramming, evaluated as higher CD86 while lower CD206 and Arg1 expression. Nanoemulsions with a PEGylated surfactant, encapsulating Stattic+Galunisertib+R848 showed faster antitumoral activity versus the free drugs. Experiments performed in IFN-γ KO mice and immune deficient mice (NSG and Balb/c nude) revealed that a fully functional immune system is crucial for the response to the treatment. In conclusion, our work demonstrates the antitumoral efficacy and reprogramming of the tumor microenvironment by combinations of TLR agonists and/or inhibitors of immunosuppression, which can be improved by nanotechnological approaches. Further investigations are ongoing to assess their antitumoral efficacy in other tumor models (i.e. breast and pancreatic cancer), with the final aim of clinical translation. Citation Format: Fernando Torres Andon, Alba Pensado-López, Clement Anfray, Aldo Ummarino, Iago Fernández-Mariño, Lucia Sanjurjo, Jose Crecente-Campo, Eduardo Fernández-Megía, Flavia Castro, Maria Jose Oliveira, Alfonso Calvo, Rosario García Campelo, Alberto Mantovani, Maria Jose Alonso, Paola Allavena. Nanomedicines loaded with TLR agonists and inhibitors of immunosuppression to reprogram the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 715.

Construction of a cascade nanosystem to implement indirect and direct cell modulation for tumor microenvironment immunostimulation

Reprogramming of tumor associated macrophages (TAMs) from M2 to M1 phenotype is becoming a feasible strategy for tumor immunotherapy, however, its efficacy is potentially constrained by the acellular components of immunosuppressive tumor microenvironment (TME). Herein, hollow MnO2 (HMnO2) nanoparticles were loaded with autophagy inhibitor chloroquine (CQ), carried both lactate oxidase (LOX) and glucose oxidase (GOX) on their surface, and further were camouflaged with tumor cell membrane, forming the final mCMLG nanoparticles for TME immunostimulation. After intravenous injection, mCMLG nanoparticles effectively accumulated in the tumor area and were taken up by tumor cells. Under the acidic conditions, MnO2 reacted with endogenous hydrogen peroxide (H2O2) to generate O2 and Mn2+, resulting in the exposure of LOX and GOX as well as the release of CQ. The exposed enzymes reduced the level of lactate (a predominant acellular component), alleviating the inhibition on TAM reprogramming; hydroxyl radical (·OH) generated by Fenton-like reaction of Mn2+ could directly promote this reprogramming, thus effectively facilitating the reprogramming of TME from immunosuppressive to immunostimulatory. Moreover, ·OH also induced chemodynamic therapy (CDT) effect against tumor cells, which was further amplified by CQ. This study corroborates that mCMLG nanoparticles can effectively inhibit tumor growth through the enhanced immunotherapy and CDT.

Nanomaterials-Involved Tumor-Associated Macrophages' Reprogramming for Antitumor Therapy.

Tumor-associated macrophages (TAMs) play pivotal roles in tumor development. As primary contents of tumor environment (TME), TAMs secrete inflammation-related substances to regulate tumoral occurrence and development. There are two kinds of TAMs: the tumoricidal M1-like TAMs and protumoral M2-like TAMs. Reprogramming TAMs from immunosuppressive M2 to immunocompetent M1 phenotype is considered a feasible way to improve immunotherapeutic efficiency. Notably, nanomaterials show great potential for biomedical fields due to their controllable structures and properties. There are many types of nanomaterials that exhibit great regulatory activities for TAMs' reprogramming. In this review, the recent progress of nanomaterials-involved TAMs' reprogramming is comprehensively discussed. The various nanomaterials for TAMs' reprogramming and the reprogramming strategies are summarized and introduced. Additionally, the challenges and perspectives of TAMs' reprogramming for efficient therapy are discussed, aiming to provide inspiration for TAMs' regulator design and promote the development of TAMs-mediated immunotherapy.

ANXA3-Rich Exosomes Derived from Tumor-Associated Macrophages Regulate Ferroptosis and Lymphatic Metastasis of Laryngeal Squamous Cell Carcinoma.

Tumor-associated macrophages (TAM) induce immunosuppression in laryngeal squamous cell carcinoma (LSCC). The interaction between LSCC cells and TAMs affects the progression of laryngeal cancer through exosomes, but the underlying molecular mechanism remains unclear. Proteomics analysis of TAMs isolated from human laryngeal tumor tissues obtained from patients with confirmed lymphatic metastasis revealed an upregulation of annexin A3 (ANXA3). In TAMs, ANXA3 promoted macrophages to polarize to an M2-like phenotype by activating the AKT-GSK3β-β-catenin pathway. In addition, ANXA3-rich exosomes derived from TAMs inhibited ferroptosis in laryngeal cancer cells through an ATF2-CHAC1 axis, and this process was associated with lymphatic metastasis. Mechanistically, ANXA3 in exosomes inhibited the ubiquitination of ATF2, whereas ATF2 acted as a transcription factor to regulate the expression of CHAC1, thus inhibiting ferroptosis in LSCC cells. These data indicate that abnormal ANXA3 expression can drive TAM reprogramming and promote an immunosuppressive microenvironment in LSCC. Meanwhile, ANXA3-rich exosomes inhibit ferroptosis of LSCC cells and promote lymphatic metastasis, thus promoting tumor progression.

Engineered Bacterial Biomimetic Vesicles Reprogram Tumor-Associated Macrophages and Remodel Tumor Microenvironment to Promote Innate and Adaptive Antitumor Immune Responses.

Tumor-associated macrophages (TAMs) are among the most abundant infiltrating leukocytes in the tumor microenvironment (TME). Reprogramming TAMs from protumor M2 to antitumor M1 phenotype is a promising strategy for remodeling the TME and promoting antitumor immunity; however, the development of an efficient strategy remains challenging. Here, a genetically modified bacterial biomimetic vesicle (BBV) with IFN-γ exposed on the surface in a nanoassembling membrane pore structure was constructed. The engineered IFN-γ BBV featured a nanoscale structure of protein and lipid vesicle, the existence of rich pattern-associated molecular patterns (PAMPs), and the costimulation of introduced IFN-γ molecules. In vitro, IFN-γ BBV reprogrammed M2 macrophages to M1, possibly through NF-κB and JAK-STAT signaling pathways, releasing nitric oxide (NO) and inflammatory cytokines IL-1β, IL-6, and TNF-α and increasing the expression of IL-12 and iNOS. In tumor-bearing mice, IFN-γ BBV demonstrated a targeted enrichment in tumors and successfully reprogrammed TAMs into the M1 phenotype; notably, the response of antigen-specific cytotoxic T lymphocyte (CTL) in TME was promoted while the immunosuppressive myeloid-derived suppressor cell (MDSC) was suppressed. The tumor growth was found to be significantly inhibited in both a TC-1 tumor and a CT26 tumor. It was indicated that the antitumor effects of IFN-γ BBV were macrophage-dependent. Further, the modulation of TME by IFN-γ BBV produced synergistic effects against tumor growth and metastasis with an immune checkpoint inhibitor in an orthotopic 4T1 breast cancer model which was insensitive to anti-PD-1 mAb alone. In conclusion, IFN-γ-modified BBV demonstrated a strong capability of efficiently targeting tumor and tuning a cold tumor hot through reprogramming TAMs, providing a potent approach for tumor immunotherapy.

Cathepsin D promotes polarization of tumor-associated macrophages and metastasis through TGFBI-CCL20 signaling

M2-like tumor-associated macrophages (TAMs) are risk factors for cancer progression and metastasis. However, the mechanisms underlying their polarization are still not fully understood. Although cathepsin D (Cat D) has been reported as a procarcinogenic factor, little is known about the functional role of Cat D in the tumor microenvironment (TME). This study aimed to explore the effect and molecular mechanisms of Cat D in the TME. Cat D knockout (KO) altered the cytokine secretion pattern and induced TAM reprogramming from the M2 to M1 subtype, thereby preventing epithelial-mesenchymal transition and tumor metastasis. Mechanistically, we identified transforming growth factor beta-induced protein (TGFBI) as a Cat D target protein that is specifically associated with TAM polarization. Elevated TGFBI expression in Cat D KO cancer cells resulted in a decline in M2-like TAM polarization. Our RNA-sequencing results indicated that the cancer cell-secreted chemokine CCL20 is a major secretory chemokine for Cat D-TGFBI-mediated TAM polarization. In contrast, Cat D overexpression accelerated TAM polarization into M2-like cells by suppressing TGFBI expression. In addition, the double Cat D and TGFBI KO rescued the inhibitory effects of Cat D KO on tumor metastasis by controlling TAM and T-cell activation. These findings indicated that Cat D contributes to cancer metastasis through TGFBI-mediated TAM reprogramming. Cat D deletion inhibits M2-like TAM polarization through TGFBI-mediated CCL20 expression, reprogramming the immunosuppressive TME. Our results open a potential new avenue for therapy focused on eliminating tumor metastasis.

Yeast-derived nanocarriers enable binary reprogramming macrophages for cancer immunotherapy

Tumor-associated macrophages (TAMs) play an important role in promoting tumor growth and metastasis, thus reprogramming TAMs to modulate the tumor immune microenvironment is a promising tumor treatment stratagem. Here, we present novel yeast-derived nanocarriers (YNCs) as IPI-549 delivery system for binary reprogramming of TAMs to induce anticancer immunity. The nanocarriers were fabricated from yeast cell walls with immune-oncology agent IPI-549 loading and coated with a shielding polymer for prolonged blood circulation. After intravenous injection, these YNCs could accumulate at the tumor site and be phagocytosed by TAMs via the Dectin-1 pathway to induce macrophage polarization towards M1 phenotype. In combination with IPI-549, the YNC system has efficiently inhibited tumor growth and modulated the tumor immune microenvironment through macrophage phenotypic alteration and increase of T cell-mediated antitumor immunity, which was demonstrated in a 4T1 orthotopic breast cancer mouse model. All these features indicate the promising values of our YNC delivery system in clinical antitumor applications.