Modulation Of Tumor Microenvironment Research Articles

Abstract 2007: Neurolysin: A novel architect of the prostate cancer microenvironment and therapeutic resistance

Abstract Introduction: Prostate cancer is the second leading cause of cancer-related death in American men, primarily driven by its ability to evade therapeutic interventions. This study uncovers a novel paradigm where neurolysin, a peptidase previously ascribed to neuronal function, orchestrates the tumor microenvironment (TME) by interfacing with cellular motor proteins. This interaction precipitates a series of events that not only fortify the cancer cells' survival but also underpin the resistance to antiandrogen therapies. Experimental Procedures: We deployed advanced prostate cancer models to delve into the extra-neuronal influence of neurolysin, probing its role in the orchestration of the TME. An exhaustive suite of transcriptomic and proteomic analyses, complemented by comprehensive patient cohort studies, laid the foundation for unraveling the complex interplay between neurolysin, motor proteins, and the TME dynamics. Results: Our data elucidates that neurolysin's depletion correlates with an altered TME, conducive to cancer proliferation and resilience against targeted therapies. This shift is mediated through neurolysin's interaction with cellular motor proteins, a liaison that appears to be a cornerstone in TME modulation. A significant subset of prostate cancer cases exhibits a neurolysin deficiency, paralleling more aggressive disease and therapeutic defiance, highlighting its role as a critical biomarker and a novel target for intervention. Conclusions: Neurolysin steps into the limelight as a pivotal modulator of the TME, operating through mechanisms distinct from its known neuronal functions. Its interplay with motor proteins opens a novel avenue in prostate cancer biology, providing a unique perspective on the regulation of the TME and subsequent therapeutic resistance. Targeting this newly discovered regulatory axis presents a promising therapeutic strategy that could potentially redefine the clinical approach to managing prostate cancer and may have implications for other malignancies driven by similar TME alterations. Citation Format: Choushi Wang, Ping Mu. Neurolysin: A novel architect of the prostate cancer microenvironment and therapeutic resistance [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 2007.

Abstract 6521: Macrophage-targeting immunotherapy enhances chemotherapy response in primary and metastatic triple-negative breast cancer models

Abstract Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype that lacks targeted treatment options. While immune checkpoint blockade leads to significant benefits in the treatment of TNBC when in combination with chemotherapy, recurrence, metastasis, and chemoresistance still remain major challenges. The purpose of this study was to assess the ability of a colony-stimulating factor 1 receptor inhibitor (CSF-1Ri) to shift the phenotype of the tumor microenvironment (TME) in murine models of TNBC, and the potential benefit of such in enhancing standard of care chemotherapy. We focused on targeting tumor-associated macrophages (TAMs) as they are the most abundant immune infiltrate in the TNBC TME and are associated with worsening overall survival (OS) and metastasis free survival (MFS). Targeting TAMs, specifically M2-like TAMs, has been shown to inhibit tumor progression and improve OS in the clinic. We selected pexidartinib (PLX) as the CSF-1Ri of choice, given its translational potential (FDA approved) and gemcitabine (GEM) as chemotherapy, given its ability to target myeloid derived suppressor cells and M2-like TAMs. For primary TNBC we employed 4T1 mammary carcinoma cells transfected with luciferase reporter gene in BALB/c mice as an immunocompetent model. Mice were injected with 100,000 cells in the 4th mammary fat pad, and tumors established over the course of fifteen days. Mice were then exposed to daily administrations of PLX (8 mg/kg), and weekly administrations of GEM (60 mg/kg). Tumor volumes were recorded every other day. The TME was analyzed with flow cytometry (FC), immunohistochemistry (IHC), and multiplex immunofluorescence (mIF). For the metastatic model, mice were inoculated with 100,000 4T1-luc cells in the flank. On day six, mice were exposed to treatments as outlined above. Mice underwent survival surgery to remove the primary tumor on day thirteen and were then treated with adjuvant therapy. Metastasis and OS were tracked. FC analysis indicated only combination therapy (11.8% ± 2.1) significantly decreased total TAMs compared to vehicle (22% ± 2) in the primary tumor. Combination therapy also showed the greatest depletion of M2-like TAMs (2.2% ± 0.6), with a significant decrease compared to both vehicle (15.6% ± 0.4) and GEM (6.6% ± 0.9). This TME modulation was confirmed using IHC and mIF. After four cycles of treatment, combination therapy (232.9 mm3 ± 130.8) had a significant effect on tumor burden compared to GEM alone (369.7 mm3 ± 165.8), indicating a correlation between tumor phenotype and therapeutic benefit. Furthermore, combination therapy led to the greatest prolongation of MFS and OS in the resection model, indicating that combination therapy has efficacy in the neoadjuvant and adjuvant setting. In conclusion, targeting TAMs in TNBC primes the tumor for combination with chemotherapy in TNBC. Citation Format: Matthew Emilio Fernandez, Yasir Alshehry, Laura Graham, Jennifer E. Koblinski, Harry D. Bear, Doug H. Sweet, Sandro R. da Rocha. Macrophage-targeting immunotherapy enhances chemotherapy response in primary and metastatic triple-negative breast cancer models [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 6521.

Abstract 5249: Macrophages expressing synthetic cytokine receptors reverse IL10-mediated immunosuppression within solid tumors and promote adaptive immunity

Abstract Motivation: In solid tumors, anti-inflammatory cytokines such as IL10 and TGFβ support an immunosuppressive tumor microenvironment (TME) and inhibit anti-tumor immunity. Many therapeutic approaches to overcome immunosuppression have used monoclonal antibodies to block cytokine signaling. Instead of silencing TME-associated cytokines, a more powerful strategy may be to leverage them as disease markers and convert them into anti-tumor signals, using a logic-gated cell-based immunotherapy. Here, we engineered macrophages with synthetic cytokine switch receptors (SR) that convert IL10 or TGFβ into pro-inflammatory signals. Macrophages are homeostatic regulators capable of both infiltrating solid tumors and initiating inflammation, and we harnessed this proficiency using SRs that convert prevalent cytokines in the TME into pro-inflammatory responses for TME modulation. We termed this engineered myeloid cell platform “Engineered Microenvironment Converters” (EM-C) and evaluated its ability to overcome cytokine-mediated immunosuppression in solid tumors. Methods: EM-C were produced by transducing primary macrophages or monocytes with a SR that converts IL10 into an interferon-based signal. The response of EM-C to IL10 was monitored in vitro using phenotypic characterization of surface molecules, measurement of secreted factors, and mRNA profiling. The in vivo activity of EM-C was evaluated using a subcutaneous tumor model in immunocompetent mice. Murine EM-C were administered to tumor-bearing mice, and their ability to modulate the TME was monitored via immunophenotyping, secretome analysis, and single cell transcriptomics. To demonstrate modularity of the EM-C platform, additional SR were designed to convert TGFβ into interferon or toll-like receptor signals. Results: EM-C efficiently sequestered IL10 or TGFβ and upregulated pro-inflammatory markers, cytokines, and pathways in a dose-dependent manner in vitro. EM-C administered to tumor-bearing mice remodeled the TME immune compartment by increasing the abundance of CD8 T cells and reducing the presence of immunosuppressive Tregs. EM-C furthermore augmented the cytokine/chemokine profile of the TME in a manner that correlated with anti-tumor response. TME modulation by EM-C improved tumor control, as compared to non-engineered macrophages, and had additive efficacy with checkpoint blockade. Conclusion: We present a versatile immunotherapy platform that harnesses macrophages as “living converters” to locally augment inflammation in solid tumors. EM-C exhibit a modular ability to locally convert IL10 or TGFβ into pro-inflammatory signals without systemic cytokine antagonism. The EM-C platform enables development of target antigen-agnostic myeloid cell immunotherapies for overcoming immunosuppression in diverse solid tumors. Citation Format: Chris Sloas, Silvia Beghi, Yuhao Huangfu, Rehman Qureshi, Benjamin Schott, Michael Ball, Daniel Blumenthal, Thomas Condamine, Michael Klichinsky, Yumi Ohtani. Macrophages expressing synthetic cytokine receptors reverse IL10-mediated immunosuppression within solid tumors and promote adaptive immunity [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 5249.

Abstract 2921: Extended treatment with IAP inhibitor xevinapant post radiotherapy improves therapeutic efficacy and promotes antitumor immunity in preclinical models

Abstract Background: Xevinapant is a first-in-class, oral IAP (inhibitor of apoptosis protein) inhibitor designed to restore cancer cell sensitivity to apoptosis induced by radiotherapy (RT) and chemotherapy. In a randomized phase 2 study of patients with unresected locally advanced squamous cell carcinoma of the head and neck, xevinapant + chemoradiotherapy (CRT) significantly improved locoregional control at 18 months, 3-year progression-free survival and nearly doubled 5-year overall survival vs. placebo + CRT (53% vs. 28%). Two phase 3 trials, in which patients receive 6 cycles of xevinapant or placebo monotherapy (3 cycles in combination with standard-of-care (C)RT followed by 3 cycles of monotherapy), are ongoing. Based on the roles of IAPs in apoptosis and tumor immunity, continual dosing of xevinapant post RT may deliver additional therapeutic benefit through modulation of multiple tumor microenvironment (TME) compartments. Methods: The impact on antitumor efficacy of xevinapant dosing duration was evaluated in A1419 (head and neck), LLC (lung) and MC38 (colorectal) syngeneic tumor-bearing mice treated with vehicle control, RT alone (3.6Gy, QD, 5 days), or RT + xevinapant (100 mg/kg, QD, 1, 2, or 4 weeks). To assess treatment-mediated TME modulation in MC38 tumors, RNAseq and FACS-based immune profiling was performed, followed by functional validation with ex vivo ELISpot assays, in vitro immunogenic cell death assays, T cell activation assays, and macrophage polarization and viability assays. To evaluate the effect of xevinapant on RT-induced cancer associated fibroblast (CAF) activation and CAF-modulated immune phenotype, activation assay and cytokine profiling was performed. Results: In the tumor models tested, RT in combination with extended xevinapant dosing markedly improved efficacy and prolonged survival compared to treatment arms of RT with shorter xevinapant dosing durations, RT alone, and vehicle control. RNAseq and FACS analyses suggested a TME with enhanced antitumor immunity, while ELISpot and in vitro T cell assays confirmed that extended xevinapant dosing promoted antigen-specific T cell response and T cell activation. Furthermore, macrophage polarization and viability assays suggested that xevinapant reduced the viability of M2 macrophages which may have contributed to the increased M1:M2 macrophage ratio and the improved antitumor immune response observed in vivo. In addition, via the suppression of RT-mediated CAF activation, xevinapant may promote M1 polarization of macrophages and recruitment of T cells by upregulating GM-CSF and CXCL10 in CAFs. Conclusions: Extended dosing of xevinapant post concurrent RT improved antitumor efficacy and prolonged survival of tumor-bearing mice. Mechanistic investigation suggested that such benefit may be, in part, modulated by xevinapant enhanced antitumor immunity. Citation Format: Tsz-Lun Yeung, Feng Jiang, Hui Huang, Huakui Yu, Li-Ya Chiu, Mathilde Bonnemaison, Bo Marelli, Roberta Ferretti, Ralph Lindemann, Christina Esdar. Extended treatment with IAP inhibitor xevinapant post radiotherapy improves therapeutic efficacy and promotes antitumor immunity in preclinical models [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 2921.

Abstract 5251: RNA primed SMAR-T cells against multiple driver mutations, all HLA's designed for first line therapy

Abstract Success of immune checkpoint inhibitors (e.g., anti-PD1 antibodies) have revolutionized cancer immunotherapy by demonstrating that a patient’s own T-cells recognize and treat cancer. The efficacy of PD-1 blockade is driven by recruitment of new T-cells from blood rather than via activation of pre-existing tumor infiltrating lymphocytes (Yost K.E., et al. Nat. Med. 2019). However, anti-PD1 therapy is most effective in ~5% of malignancies i.e., cancers with high mutational burden. Hence, the challenge of addressing most lower mutational burden cancers (the ~95%) needs an alternate treatment strategy. We address this challenge by using RNA to prime and expand peripheral T-cells to cancer-specific mutations ex-vivo. Using our proprietary, patented, and robust manufacturing method, we can generate T-cell populations reactive to as low as 8 and as high as 40 cancer-specific mutant proteins. In-vitro, these T-cells have cancer mutation-specific cytotoxicity and do not kill the normal cells. Further, the T-cells express homing receptors enabling them to infiltrate tumors and express high levels of TNFα and IFNγ, which are associated with effective tumor cytotoxicity and pro-inflammatory modification of tumor microenvironment (TME). Additional characterization shows these cells to be predominantly CD4+ and CD8+ T-cells bearing central and effector memory phenotypic with negligible regulatory or exhausted T-cells. We believe our T-cells can be used for cellular therapy in conjunction with, or as an alternative to, immune checkpoint inhibitors to treat lower mutational burden cancers present in most patients. Citation Format: Alfred E. Slanetz, Sriram Srivatsa, Farzona Muzaffar, Walter Barry, David Ryan, Salim Metri, Michael Slanetz. RNA primed SMAR-T cells against multiple driver mutations, all HLA's designed for first line therapy [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 5251.

Abstract 162: Fatty acid synthesis blockade synergizes with immune checkpoint blockade by repolarizing macrophages and enhancing anti-tumor cytotoxicity in gastric cancer

Abstract Background: Immune checkpoint blockade (ICB), which unleashes potent CD8+ T cell-based anti-tumor responses, has emerged as a promising therapeutic option for several cancer types. However, response rates stay limited in gastric cancer (GC) patients, indicating the necessity of combinational strategies to overcome other immunosuppressive factors. Fatty acid synthesis (FAS) is an indispensable metabolic pathway proven to support cancer cell survival. The rate-limiting enzyme of FAS, FASN, is upregulated in several cancers and could contribute to cancer immune escape. Though some investigations propose that specific gene alterations can cause FASN upregulation under the GC setting, the immunoregulatory role and therapeutic value of FASN in the tumor microenvironment (TME) of GC have not been fully elucidated. Methods: FASN expression was measured by Western Blotting and flow cytometry. Bioinformatic analysis was conducted via an online website (www.camoip.net). The syngeneic GC mouse model was established by subcutaneous inoculation of MFC cells in 615-line mice, treated by vehicles, FASN inhibitor (FASNi), anti-PD-1 antibodies, or FASNi+anti-PD-1 antibodies. TAM and CD8+ T cell depletion was implemented by anti-CSF1R and anti-CD8α antibodies. Bone marrow-derived macrophages (BMDMs) were extracted from the femurs of 615-line mice, induced by M-CSF and stimulated by LPS or IL-4. The proportions and functional status of immune cells were identified by flow cytometry. Results: FASN was upregulated in GC tissues and GC human cell lines. Bioinformatic analyses demonstrated that FASN expression was related to poor infiltration of cytotoxic lymphocytes, as well as the downregulation of pathways related to anti-cancer immune responses. FASNi inhibited tumor growth in a syngeneic GC mouse model, with elevated PD-1 and IFN-γ expression in CD8+ T cells and increased NK cell infiltration, suggesting the enhancement in anti-cancer cytotoxicity. Meanwhile, FASNi induced a shift from M2-like to M1-like in tumor-associated macrophages (TAM). We detected that M2-like TAM and CD8+ T cells harbored higher FASN expression than other immune cells in GC mouse tissues, and tumor-suppressing effects of FASN inhibition could be reversed by TAM and CD8+ T cell depletion, which corroborated the key role of TAM and CD8+ T cells in shaping FASN-mediated tumor regulation. FASNi could also repolarize BMDMs from M1-like to M2-like in vitro. Finally, FASNi exhibited synergistic tumor control with anti-PD-1 therapy in GC and melanoma mouse models. Conclusion: This work sheds light on the impact of FASN on TME modulation of GC. We proved that FASNi could repolarize M2-like TAM to M1 phenotypes and promote cytotoxic lymphocyte-mediated anti-tumor immunity. Our results propose FASN inhibition as a potential therapeutic strategy to sensitize ICB therapy in GC. Citation Format: Hanbing Wang, Tao Shi, Yue Wang, Yuting Luo, Yunfeng Pan, Xiaoyu Zhou, Yue Zhang, Baorui Liu, Jia Wei. Fatty acid synthesis blockade synergizes with immune checkpoint blockade by repolarizing macrophages and enhancing anti-tumor cytotoxicity in gastric cancer [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 162.

Abstract 1948: Resistance to RAS inhibition promotes remodeling of the immunosuppressive microenvironment of pancreatic cancer

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, largely due to acquired chemotherapy resistance. MRTX-1133, a promising KRAS-G12D inhibitor, has demonstrated initial efficacy; however, resistance analogous to that seen with KRAS-G12C inhibitors is an emerging challenge. The tumor microenvironment (TME) is increasingly recognized as a contributor to resistance, often fostering tumor survival and immune evasion. Methods: To elucidate the resistance mechanisms to KRAS-G12D inhibition, we established resistant mouse and human PDAC cell lines derived from mouse and human models. These models were analyzed using flow cytometry and single cell RNA sequencing to define TME dynamics as resistant is acquired and after is has been established. We also analyzed cytokines released by resistant tumor cells using protein arrays and RNA sequencing. Results: Our investigation revealed significant TME alterations associated with acquired resistance. Notably, there was a marked increase in the population CD4+ Tregs and neutrophil while activated CD8+ T cells are decreased in the resistant tumors. Concurrently, an increased secretion of chemokines such as CXCL1 and CXCL2 was observed in resistant tumor cells relative to their parental counterparts. Conclusions: The adaptation of PDAC to circumvent KRAS inhibition involves a distinct reprogramming of the TME, attenuating immune surveillance and potentially facilitating tumor progression. Current efforts are directed towards delineating the key pathways implicated in these TME modifications to pioneer new therapeutic approaches for managing KRAS inhibitor resistant PDAC. Citation Format: Herve Tiriac. Resistance to RAS inhibition promotes remodeling of the immunosuppressive microenvironment of pancreatic cancer [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 1948.

Cimetidine Attenuates Therapeutic Effect of Anti-PD-1 and Anti-PD-L1 and Modulates Tumor Microenvironment in Colon Cancer.

Histamine modulates immunity by binding to histamine receptor 2 (H2R). Cimetidine, an H2R antagonist that inhibits gastric acid secretion and treats gastrointestinal ulcers, interferes with histamine-mediated immunomodulation and may have anticancer activity. This study examined cimetidine's effect on the anticancer effect of anti-PD-L1 in colon cancer. The MTT assay, colony formation assay, and DNA histograms assessed cell viability, clonogenicity, and cell cycle distribution, respectively. Flow cytometry measured H2R and PD-L1 expression and estimated specific immune cell lineages. For the in vivo study, tumor cells were subcutaneously implanted into the right flank of BALB/c mice. Cimetidine had no significant effect on CT26 cell viability, clonogenicity, or cell cycle distribution. It also did not affect H2R and PD-L1 expression levels in CT26 cells. In vivo, anti-PD-1 and anti-PD-L1 suppressed CT26 tumor growth, whereas cimetidine showed mild antitumor activity. In the combined experiment, cimetidine significantly attenuated anti-PD-1 and anti-PD-L1' antitumor effects without major toxicity. In the tumor microenvironment, anti-PD-L1 increased CD3+ T, CD4+ T, and CD8+ T cells and M1 macrophages. Combined treatment with cimetidine reversed this. Cimetidine also reversed anti-PD-1 and anti-PD-L1's decrease in circulating and tumor-associated neutrophils. Cimetidine attenuated anti-PD-L1's antitumor effect and modulated the tumor microenvironment in colon cancer.

Establishment of a Novel Anti-Mouse CCR1 Monoclonal Antibody C1Mab-6.

C-C motif chemokine receptor 1 (CCR1/CD191) is a member of G-protein-coupled receptors and is expressed on myeloid cells, such as neutrophils and macrophages. Because the CCR1 signaling promotes tumor expansion in the tumor microenvironment (TME), the modification of TME is an effective strategy for cancer therapy. Although CCR1 is an attractive target for solid tumors and hematological malignancies, therapeutic agents for CCR1 have not been approved. Here, we established a novel anti-mouse CCR1 (mCCR1) monoclonal antibody (mAb), C1Mab-6 (rat IgG2b, kappa), using the Cell-Based Immunization and Screening method. Flow cytometry and Western blot analyses showed that C1Mab-6 recognizes mCCR1 specifically. The dissociation constant of C1Mab-6 for mCCR1-overexpressed Chinese hamster ovary-K1 was determined as 3.9 × 10-9 M, indicating that C1Mab-6 possesses a high affinity to mCCR1. These results suggest that C1Mab-6 could be a useful tool for targeting mCCR1 in preclinical mouse models.

Exosome proteomes reveal glycolysis-related enzyme enrichment in primary canine mammary gland tumor compared to metastases

ObjectiveNumerous evidence has highlighted the differences between primary tumors and metastases. Nonetheless, the differences in exosomal proteins derived from primary tumor and metastases remain elusive. Here, we aimed to identify differentially expressed exosomal proteins from primary canine mammary gland tumor and metastases to understand how they shape their own tumor microenvironment.MethodsWe clearly distinguished primary canine mammary gland tumors (CHMp) from metastases (CHMm) and profiled the proteins within their secreted exosomes using LC–MS/MS. Moreover, the abundance of glycolysis enzymes (GPI, LDHA) in CHMp exosome was verified with Western blotting, To broaden the scope, we extended to human colorectal cancer-derived exosomes (SW480 vs. SW620) for comparison.ResultsWe identified significant differences in 87 and 65 proteins derived from CHMp and CHMm, respectively. Notably, glycolysis enzymes (GPI, LDHA, LDHB, TPI1, and ALDOA) showed specific enrichment in exosomes from the primary tumor.ConclusionWe observed significant differences in the cellular proteome between primary tumors and metastases, and intriguingly, we identified a parallel heterogeneity the protein composition of exosomes. Specifically, we reported that glycolysis enzymes were significantly enriched in CHMp exosomes compared to CHMm exosomes. We further demonstrated that this quantitative difference in glycolysis enzymes persisted across primary and metastases, extending to human colorectal cancer-derived exosomes (SW480 vs. SW620). Our findings of the specific enrichment of glycolysis enzymes in primary tumor-derived exosomes contribute to a better understanding of tumor microenvironment modulation and heterogeneity between primary tumors and metastases.

Investigating the synergistic effects of immunotherapy and normalization treatment in modulating tumor microenvironment and enhancing treatment efficacy

We developed a comprehensive mathematical model of cancer immunotherapy that takes into account: i) Immune checkpoint blockers (ICBs) and the interactions between cancer cells and the immune system, ii) characteristics of the tumor microenvironment, such as the tumor hydraulic conductivity, interstitial fluid pressure, and vascular permeability, iii) spatial and temporal variations of the modeled components within the tumor and the surrounding host tissue, iv) the transport of modeled components through the vasculature and between the tumor-host tissue with convection and diffusion, and v) modeling of the tumor draining lymph nodes were the antigen presentation and the development of cytotoxic immune cells take place. Our model successfully reproduced experimental data from various murine tumor types and predicted immune system profiling, which is challenging to achieve experimentally. It showed that combination of ICB therapy and normalization treatments, that aim to improve tumor perfusion, decreases interstitial fluid pressure and increases the concentration of both innate and adaptive immune cells at the tumor center rather than the periphery. Furthermore, using the model, we investigated the impact of modeled components on treatment outcomes. The analysis found that the number of functional vessels inside the tumor region and the ICB dose administered have the largest impact on treatment outcomes.

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.

Impact of metronomic trabectedin combined with low-dose cyclophosphamide on sarcoma microenvironment and correlation with clinical outcome: results from the TARMIC study.

Soft tissue sarcomas (STS) are diverse mesenchymal tumors with few therapeutic options in advanced stages. Trabectedin has global approval for treating STS patients resistant to anthracycline-based regimens. Recent pre-clinical data suggest that trabectedin's antitumor activity extends beyond tumor cells to influencing the tumor microenvironment (TME), especially affecting tumor-associated macrophages and their pro-tumoral functions. We present the phase I/II results evaluating a combination of metronomic trabectedin and low-dose cyclophosphamide on the TME in patients with advanced sarcomas. 50 patients participated: 20 in phase I and 30 in phase II. Changes in the TME were assessed in 28 patients using sequential tumor samples at baseline and day two of the cycle. Treatment notably decreased CD68 + CD163 + macrophages in biopsies from tumor lesions compared to pre-treatment samples in 9 of the 28 patients after 4 weeks. Baseline CD8 + T cell presence increased in 11 of these patients. In summary, up to 57% of patients exhibited a positive immunological response marked by reduced M2 macrophages or increased CD8 + T cells post-treatment. This positive shift in the TME correlated with improved clinical benefit and progression-free survival. This study offers the first prospective evidence of trabectedin's immunological effect in advanced STS patients, highlighting a relationship between TME modulation and patient outcomes.This study was registered with ClinicalTrial.gov, number NCT02406781.

Sudocetaxel Zendusortide (TH1902) triggers the cGAS/STING pathway and potentiates anti-PD-L1 immune-mediated tumor cell killing.

The anticancer efficacy of Sudocetaxel Zendusortide (TH1902), a peptide-drug conjugate internalized through a sortilin-mediated process, was assessed in a triple-negative breast cancer-derived MDA-MB-231 immunocompromised xenograft tumor model where complete tumor regression was observed for more than 40 days after the last treatment. Surprisingly, immunohistochemistry analysis revealed high staining of STING, a master regulator in the cancer-immunity cycle. A weekly administration of TH1902 as a single agent in a murine B16-F10 melanoma syngeneic tumor model demonstrated superior tumor growth inhibition than did docetaxel. A net increase in CD45 leukocyte infiltration within TH1902-treated tumors, especially for tumor-infiltrating lymphocytes and tumor-associated macrophages was observed. Increased staining of perforin, granzyme B, and caspase-3 was suggestive of elevated cytotoxic T and natural killer cell activities. Combined TH1902/anti-PD-L1 treatment led to increases in tumor growth inhibition and median animal survival. TH1902 inhibited cell proliferation and triggered apoptosis and senescence in B16-F10 cells in vitro, while inducing several downstream effectors of the cGAS/STING pathway and the expression of MHC-I and PD-L1. This is the first evidence that TH1902 exerts its antitumor activity, in part, through modulation of the immune tumor microenvironment and that the combination of TH1902 with checkpoint inhibitors (anti-PD-L1) could lead to improved clinical outcomes.

Extracellular vesicles produced by irradiated endothelial or Glioblastoma stem cells promote tumor growth and vascularization modulating tumor microenvironment

BackgroundGlioblastoma (GBM) is the most lethal primary brain tumor in adult, characterized by highly aggressive and infiltrative growth. The current therapeutic management of GBM includes surgical resection followed by ionizing radiations and chemotherapy. Complex and dynamic interplay between tumor cells and tumor microenvironment drives the progression and contributes to therapeutic resistance. Extracellular vesicles (EVs) play a crucial role in the intercellular communication by delivering bioactive molecules in the surrounding milieu modulating tumor microenvironment.MethodsIn this study, we isolated by ultracentrifugation EVs from GBM stem-like cell (GSC) lines and human microvascular endothelial cells (HMVECs) exposed or not to ionizing irradiation. After counting and characterization, we evaluated the effects of exposure of GSCs to EVs isolated from endothelial cells and vice versa. The RNA content of EVs isolated from GSC lines and HMVECs exposed or not to ionizing irradiation, was analyzed by RNA-Seq. Periostin (POSTN) and Filamin-B (FLNB) emerged in gene set enrichment analysis as the most interesting transcripts enriched after irradiation in endothelial cell-derived EVs and GSC-derived EVs, respectively. POSTN and FLNB expression was modulated and the effects were analyzed by in vitro assays.ResultsWe confirmed that ionizing radiations increased EV secretion by GSCs and normal endothelial cells, affected the contents of and response to cellular secreted EVs. Particularly, GSC-derived EVs decreased radiation-induced senescence and promoted migration in HMVECs whereas, endothelial cell-derived EVs promoted tumorigenic properties and endothelial differentiation of GSCs. RNA-Seq analysis of EV content, identified FLNB and POSTN as transcripts enriched in EVs isolated after irradiation from GSCs and HMVECs, respectively. Assays performed on POSTN overexpressing GSCs confirmed the ability of POSTN to mimic the effects of endothelial cell-derived EVs on GSC migration and clonogenic abilities and transdifferentiation potential. Functional assays performed on HMVECs after silencing of FLNB supported its role as mediator of the effects of GSC-derived EVs on senescence and migration.ConclusionIn this study, we identified POSTN and FLNB as potential mediators of the effects of EVs on GSC and HMVEC behavior confirming that EVs play a crucial role in the intercellular communication by delivering bioactive molecules in the surrounding milieu modulating tumor microenvironment.

Extracellular vesicles as modulators of glioblastoma progression and tumor microenvironment.

Glioblastoma is the most aggressive brain tumor with extremely poor prognosis in adults. Routine treatments include surgery, chemotherapy, and radiotherapy; however, these may lead to rapid relapse and development of therapy-resistant tumor. Glioblastoma cells are known to communicate with macrophages, microglia, endothelial cells, astrocytes, and immune cells in the tumor microenvironment (TME) to promote tumor preservation. It was recently demonstrated that Glioblastoma-derived extracellular vesicles (EVs) participate in bidirectional intercellular communication in the TME. Apart from promoting glioblastoma cell proliferation, migration, and angiogenesis, EVs and their cargos (primarily proteins and miRNAs) can act as biomarkers for tumor diagnosis and prognosis. Furthermore, they can be used as therapeutic tools. In this review, the mechanisms of Glioblastoma-EVs biogenesis and intercellular communication with TME have been summarized. Moreover, there is discussion surrounding EVs as novel diagnostic structures and therapeutic tools for glioblastoma. Finally, unclear questions that require future investigation have been reviewed.

Breaking-Down Tumoral Physical Barrier by Remotely Unwrapping Metal-Polyphenol-Packaged Hyaluronidase for Optimizing Photothermal/Photodynamic Therapy-Induced Immune Response.

The therapy of solid tumors is often hindered by the compact and rigid tumoral extracellular matrix (TECM). Precise reduction of TECM by hyaluronidase (HAase) in combination with nanotechnology is promising for solid tumor therapeutics, yet remains an enormous challenge. Inspired by the treatment of iron poisoning, here a remotely unwrapping strategy is proposed of metal-polyphenol-packaged HAase (named PPFH) by sequentially injecting PPFH and a clinically used iron-chelator deferoxamine (DFO). The in situ dynamic disassembly of PPFH can be triggered by the intravenously injected DFO, resulting in the release, reactivation, and deep penetration of encapsulated HAase inside tumors. Such a cost-effective HAase delivery strategy memorably improves the subsequent photothermal and photodynamic therapy (PTT/PDT)-induced intratumoral infiltration of cytotoxic T lymphocyte cells and the cross-talk between tumor and tumor-draining lymph nodes (TDLN), thereby decreasing the immunosuppression and optimizing tumoricidal immune response that can efficiently protect mice from tumor growth, metastasis, and recurrence in multiple mouse cancer models. Overall, this work presents a proof-of-concept of the dynamic disassembly of metal-polyphenol nanoparticles for extracellular drug delivery as well as the modulation of TECM and immunosuppressive tumor microenvironment.

Obesity-associated epigenetic alterations and the obesity-breast cancer axis.

Both breast cancer and obesity can regulate epigenetic changes or be regulated by epigenetic changes. Due to the well-established link between obesity and an increased risk of developing breast cancer, understanding how obesity-mediated epigenetic changes affect breast cancer pathogenesis is critical. Researchers have described how obesity and breast cancer modulate the epigenome individually and synergistically. In this review, the epigenetic alterations that occur in obesity, including DNA methylation, histone, and chromatin modification, accelerated epigenetic age, carcinogenesis, metastasis, and tumor microenvironment modulation, are discussed. Delineating the relationship between obesity and epigenetic regulation is vital to furthering our understanding of breast cancer pathogenesis.

Hepatitis B virus-related hepatocellular carcinoma exhibits distinct intratumoral microbiota and immune microenvironment signatures.

Emerging evidence supports a high prevalence of cancer type-specific microbiota residing within tumor tissues. The intratumoral microbiome in hepatocellular carcinoma (HCC), especially in viral (hepatitis B virus [HBV]/hepatitis C virus [HCV]) HCC, has not been well characterized for their existence, composition, distribution, and biological functions. We report herein a finding of specific microbial signature in viral HCC as compared to non-HBV/non-HCV (NBNC) HCC. However, the significantly diverse tumor microbiome was only observed in HBV-related HCC, and Cutibacterium was identified as the representative taxa biomarker. Biological function of the unique tumor microbiota in modulating tumor microenvironment (TME) was characterized by using formalin-fixed paraffin-embedded (FFPE) tissue-based multiplex immunofluorescence histochemistry (mIFH) allowing simultaneous in situ detection of the liver cancer cells surrounded with high/low density of microbiota, and the infiltrating immune cells. In HBV_HCC, the intratumoral microbiota are positively associated with increased tumor-infiltrating CD8+ T lymphocytes, but not the CD56+ NK cells. Two subtypes of myeloid-derived suppressor cells (MDSCs): monocytic MDSCs and polymorphonuclear MDSCs, were also found to be positively correlated with the intratumoral microbiota in HBV_HCC, indicating an inhibitory role of these microbial species in antitumor immunity and the contribution to the liver TME in combination of chronic viral hepatitis during HCC development.

Inflammation-Driven Nanohitchhiker Enhances Postoperative Immunotherapy by Alleviating Prostaglandin E2-Mediated Immunosuppression.

Inflammation contributes to the immunosuppressive microenvironment and leads to the recurrence of surgically resected tumors. The COX-2/PGE2 axis is considered a key player in shaping the immunosuppression microenvironment. However, targeted modulation of the postoperative tumor microenvironment is challenging. To specifically curb the inflammation and alleviate immunosuppression, here, we developed a PGE2 inhibitor celecoxib (CXB)-loaded bionic nanoparticle (CP@CM) coated with activated murine vascular endothelial cell (C166 cells) membrane to target postoperative melanoma and inhibit its recurrence. CP@CM adhered to inflammatory white blood cells (WBCs) through the adhesion molecules, including ICAM-1, VCAM-1, E-selectin, and P-selection, expressed on the surface of C166 cells. Leveraging the natural tropism of the WBC to the inflammatory postoperative tumor site, CP@CM efficiently targeted postoperative tumors. In melanoma postoperative recurrence models, CXB significantly reduced PGE2 secretion and the recruitment of immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Treg) by inhibiting the activity of COX-2. This was followed by an increase in the infiltration of CD8+ T cells and CD4+ T cells in tumor tissues. Additionally, the immune responses were further enhanced by combining a PD-L1 monoclonal antibody. Ultimately, this immunotherapeutic strategy reversed the tumor immunosuppressive microenvironment and inhibited tumor recurrence, demonstrating a promising potential for postoperative immunotherapy for melanoma.