Restrict Tumor Growth Research Articles

RNF2 promotes chondrosarcoma progression by regulating ubiquitination and degradation of CBX7

ObjectiveChondrosarcoma (CHS) is resistant to conventional chemotherapy and radiotherapy and currently lacks effective treatment options when in advanced stages. Accordingly, this research investigated the mechanism of RNF2/CBX7 in CHS to drive the development of molecularly targeted drugs for CHS.MethodsRNF2 and CBX7 levels were detected in CHS cells and tissues. RNF2 and CBX7 expression was modulated through cell transfection to examine their effects on cell proliferation, apoptosis, migration, and angiogenesis. The correlation between RNF2 and CBX7 levels was determined, and the ubiquitination level of CBX7 was tested. Protein synthesis was blocked in RNF2-knockdown/overexpressing cells with CHX to assess the effect of RNF2 on CBX7 stability. JJ012 cells transfected with LV-sh-RNF2 were subcutaneously injected into nu/nu nude mice to ascertain the action of RNF2 in the growth and metastasis of CHS.ResultsRNF2 was highly expressed in CHS cells and tissues. RNF2 knockdown curbed CHS cell proliferation, migration, and angiogenesis while promoting apoptosis. RNF2 knockdown in JJ012 cells upregulated CBX7 protein levels and reduced CBX7 ubiquitination, whilst RNF2 had no effect on CBX7 mRNA expression. CBX7 knockdown partially nullified the repressing effects of RNF2 knockdown on CHS cell proliferation, migration, and angiogenesis, and CBX7 overexpression partially abolished the promotional effects of RNF2 overexpression. LV-sh-RNF2 prominently restricted tumor growth and weight and declined lung metastatic nodules and Ki-67-positive cells in mice.ConclusionRNF2 fosters CHS progression by elevating CBX7 degradation via the ubiquitination pathway.

Trem2 deficiency attenuates breast cancer tumor growth in lean, but not obese or weight loss, mice and is associated with alterations of clonal T cell populations.

Obesity is an established risk factor for breast cancer development and worsened prognosis; however, the mechanisms for this association - and the potential benefits of weight loss - have not been fully explored. The adipose environment surrounding breast tumors, which is inflamed in obesity, has been implicated in tumor progression. An emerging therapeutic target for cancer is TREM2, a transmembrane receptor of the immunoglobulin superfamily that is expressed on macrophages in adipose tissue and tumors. We utilized genetic loss of function (Trem2 +,+ and Trem2 -/-) models and dietary (lean, obese, and weight loss) intervention approaches to examine impacts on postmenopausal breast cancer. Remarkably, Trem2 deficiency ameliorated tumor growth in lean, but not obese or weight loss mice. Single-cell RNA sequencing, in conjunction with VDJ sequencing of tumor and tumor-adjacent mammary adipose tissue (mATTum-adj) immune cells, revealed that tumors of lean Trem2 -/- mice exhibited a shift in clonal CD8+ T cells from an exhausted to an effector memory state, accompanied with increased clonality of CD4+ Th1 cells, that was not observed in any other diet-genotype group. Notably, identical T cell clonotypes were identified in the tumor and mATTum-adj of the same mouse. Finally, an immune checkpoint study demonstrated that αPD-1 therapy restricted tumor growth in lean and weight loss, but not obese mice. We conclude that weight history is relevant when considering potential efficacy of TREM2 inhibition in postmenopausal breast cancer. This work reveals immunological interactions between tumors and surrounding adipose tissue, highlighting significant differences under obese and weight loss conditions.

Dendrobine Suppresses Tumor Growth by Regulating the PD-1/PD-L1 Checkpoint Pathway in Lung Cancer

Background: Dendrobine is a bioactive alkaloid isolated from Dendrobium nobile. Studies have evaluated the anti-tumor effect of dendrobine in cancers, including lung cancer. However, the mechanism of dendrobine inhibiting tumors requires further study. Methods: Bioinformatics was performed to screen the potential targets of dendrobine. The in-tersection of dendrobine and lung cancer targets was performed for KEGG analysis. CCK-8 was used to detect cell viability after dendrobine treatment. A xenograft mouse model was es-tablished to explore the effect of dendrobine on lung cancer. The percentages of PD-L1+, CD4+, CD8+, CD11b+, CD25+FOXP3+ cells, the expression of Ki-67 and caspase-3, the ex-pression of pathway-related proteins, the levels of IL-2, IFN-γ, and TGF-β, and the changes of indicators of liver and renal function were measured. Results: Dendrobine regulated the PD1/PD-L1 checkpoint signaling pathway and affected the occurrence and development of lung cancer. Dendrobine decreased the cell viability of lung cancer. Dendrobine and anti-PD-L1 decreased tumor growth, increased caspase-3 expression, and reduced Ki-67 expression in tumor tissues. Dendrobine and anti-PD-L1 suppressed pro-tein expression of PD-L1, p-JAK1/JAK1, and p-JAK2/JAK2 in tumor tissues. Greatly, den-drobine and anti-PD-L1 decreased the percentages of PD-L1+, CD11b+, and CD25+FOXP3+ cells, increased the percentages of CD4+ and CD8+cells, and enhanced the levels of IL-2, IFN-γ, and TGF-β in tumor tissues. Dendrobine demonstrated no hepatorenal toxicity to the tumor mice. The combination of dendrobine and anti-PD-L1 greatly strengthened the effects of dendrobine on tumors. Conclusion: Dendrobine inhibited tumor immune escape by suppressing the PD-1/PD-L1 checkpoint pathway, thus restricting tumor growth of lung cancer. conclusion: Dendrobiine inhibited tumor immune escape by suppressing PD-1/PD-L1 checkpoint pathway, thus restricting tumor growth of lung cancer. other: N/A

Targeting Asparagine Metabolism in Well-Differentiated/Dedifferentiated Liposarcoma.

mTORC1 activity is dependent on the presence of micronutrients, including Asparagine (Asn), to promote anabolic cell signaling in many cancers. We hypothesized that targeting Asn metabolism would inhibit tumor growth by reducing mTORC1 activity in well-differentiated (WD)/dedifferentiated (DD) liposarcoma (LPS). Human tumor metabolomic analysis was utilized to compare abundance of Asn in WD vs. DD LPS. Gene set enrichment analysis (GSEA) compared relative expression among metabolic pathways upregulated in DD vs. WD LPS. Proliferation assays were performed for LPS cell lines and organoid models by using the combination treatment of electron transport chain (ETC) inhibitors with Asn-free media. 13C-Glucose-labeling metabolomics evaluated the effects of combination treatment on nucleotide synthesis. Murine xenograft models were used to assess the effects of ETC inhibition combined with PEGylated L-Asparaginase (PEG-Asnase) on tumor growth and mTORC1 signaling. Asn was enriched in DD LPS compared to WD LPS. GSEA indicated that mTORC1 signaling was upregulated in DD LPS. Within available LPS cell lines and organoid models, the combination of ETC inhibition with Asn-free media resulted in reduced cell proliferation. Combination treatment inhibited nucleotide synthesis and promoted cell cycle arrest. In vivo, the combination of ETC inhibition with PEG-Asnase restricted tumor growth. Asn enrichment and mTORC1 upregulation are important factors contributing to WD/DD LPS tumor progression. Effective targeting strategies require limiting access to extracellular Asn and inhibition of de novo synthesis mechanisms. The combination of PEG-Asnase with ETC inhibition is an effective therapy to restrict tumor growth in WD/DD LPS.

A single-cell analysis of the NK-cell landscape reveals that dietary restriction boosts NK cell antitumor immunity via Eomesdermin.

Abnormal metabolism in tumor cells represents a potential target for tumor therapy. In this regard, dietary restriction (DR) or its combination with anticancer drugs is of interest as it can impede the growth of tumor cells. In addition to its effects on tumor cell, DR also plays an extrinsic role in restricting tumor growth by regulating immune cells. Natural killer (NK) cells are innate immune cells involved in tumor immunosurveillance. However, it remains uncertain whether DR can assist NK cells in controlling tumor growth. Herein, we demonstrate that DR effectively inhibits metastasis of melanoma cells to the lung. Consistent with this, the regression of tumors induced by DR was minimal in mice lacking NK cells. Single-cell RNA sequencing analysis revealed that DR enriched a rejuvenated subset of CD27+CD11b+ NK cells. Mechanistically, DR activated a regulatory network involving the transcription factor Eomesodermin (Eomes), which is essential for NK-cell development. Firstly, DR promoted the expression of Eomes by optimizing mTORC1 signaling. The upregulation of Eomes revived the subset of functional CD27+CD11b+ NK cells by counteracting the expression of T-bet and downstream Zeb2. Moreover, DR enhanced the function and chemotaxis of NK cells by increasing the accessibility of Eomes to chromatin, leading to elevated expression of adhesion molecules and chemokines. Consequently, we conclude that DR therapy enhances tumor immunity through non-tumor autonomous mechanisms, including promoting NK-cell tumor immunosurveillance and activation.

ZBTB46 coordinates angiogenesis and immunity to control tumor outcome.

Tumor angiogenesis and immunity show an inverse correlation in cancer progression and outcome1. Here, we report that ZBTB46, a repressive transcription factor and a widely accepted marker for classical dendritic cells (DCs)2,3, controls both tumor angiogenesis and immunity. Zbtb46 was downregulated in both DCs and endothelial cells by tumor-derived factors to facilitate robust tumor growth. Zbtb46 downregulation led to a hallmark pro-tumor microenvironment (TME), including dysfunctional vasculature and immunosuppressive conditions. Analysis of human cancer data revealed a similar association of low ZBTB46 expression with an immunosuppressive TME and a worse prognosis. In contrast, enforced Zbtb46 expression led to TME changes to restrict tumor growth. Mechanistically, Zbtb46-deficient endothelial cells were highly angiogenic, and Zbtb46-deficient bone marrow progenitors upregulated Cebpb and diverted the DC program to immunosuppressive myeloid lineage output, potentially explaining the myeloid lineage skewing phenomenon in cancer4. Conversely, enforced Zbtb46 expression normalized tumor vessels and, by suppressing Cebpb, skewed bone marrow precursors toward immunostimulatory myeloid lineage output, leading to an immune-hot TME. Remarkably, Zbtb46 mRNA treatment synergized with anti-PD1 immunotherapy to improve tumor management in preclinical models. These findings identify ZBTB46 as a critical factor for angiogenesis and for myeloid lineage skewing in cancer and suggest that maintaining its expression could have therapeutic benefits.

A Novel Oncogenic Role of Disulfidptosis-related Gene SLC7A11 in Anti-tumor Immunotherapy Response to Human Cancers.

The protein Solute Carrier Family 7 Member 11 (SLC7A11) plays a pivotal role in cellular redox homeostasis by suppressing disulfidptosis, which restricts tumor growth. Yet, its relevance in prognosis, immunity, and cancer treatment efficacy is not well understood. We conducted a comprehensive analysis of the expression of SLC7A11 across 33 cancer types, employing datasets from public databases. Methods, such as Cox regression and survival analyses assessed its prognostic significance, while functional enrichment explored the biological processes tied to SLC7A11. The association between SLC7A11 expression, immune cell infiltration, and immune-related gene expression was also scrutinized. Notably, SLC7A11 expression was more pronounced in cancerous compared to normal samples and correlated with higher tumor grades. Increased SLC7A11 expression was linked to poor outcomes, particularly in liver hepatocellular carcinoma (LIHC). This protein's expression also showcased significant relationships with diverse molecular and immune subtypes. Additionally, a prognostic nomogram was devised, integrating SLC7A11 expression and clinical variables. High SLC7A11 levels corresponded with cell growth and senescence pathways in various cancers and with lipid and cholesterol metabolism in LIHC. Furthermore, potential therapeutic compounds for LIHC with high SLC7A11 were identified. Real-time PCR (qPCR) and Western blot were conducted to explore the expression of SLC7A11 in tumor tissues and cancer cell lines. In summation, this study emphasizes the prognostic and immunological importance of SLC7A11, spotlighting its potential as a therapeutic target in LIHC.

Granulocytes and mast cells in AllergoOncology-Bridging allergy to cancer: An EAACI position paper.

Derived from the myeloid lineage, granulocytes, including basophils, eosinophils, and neutrophils, along with mast cells, play important, often disparate, roles across the allergic disease spectrum. While these cells and their mediators are commonly associated with allergic inflammation, they also exhibit several functions either promoting or restricting tumor growth. In this Position Paper we discuss common granulocyte and mast cell features relating to immunomodulatory functions in allergy and in cancer. We highlight key mechanisms which may inform cancer treatment and propose pertinent areas for future research. We suggest areas where understanding the communication between granulocytes, mast cells, and the tumor microenvironment, will be crucial for identifying immune mechanisms that may be harnessed to counteract tumor development. For example, a comprehensive understanding of allergic and immune factors driving distinct neutrophil states and those mechanisms that link mast cells with immunotherapy resistance, might enable targeted manipulation of specific subpopulations, leading to precision immunotherapy in cancer. We recommend specific areas of investigation in AllergoOncology and knowledge exchange across disease contexts to uncover pertinent reciprocal functions in allergy and cancer and allow therapeutic manipulation of these powerful cell populations. These will help address the unmet needs in stratifying and managing patients with allergic diseases and cancer.

Neutrophil-based Trojan horse containing polymer nano-therapeutics for sono-activatable ferroptosis-immunotherapy of orthotopic glioma

The blood-brain barrier (BBB) and tumor microenvironment of glioma limit the efficacies of various therapies, and thus glioma treatment is challenging. We herein report semiconducting polymer nano-therapeutics (SPCFe/siP) that can achieve efficient delivery into orthotopic glioma sites via neutrophil-mediated BBB transport for sono-activatable ferroptosis-immunotherapy. Such SPCFe/siP contain a semiconducting polymer, programmed death-ligand 1 (PD-L1) siRNA and iron oxide (Fe3O4) nanoparticles loaded into a singlet oxygen (1O2)-cleavable nanocarrier with surface conjugation of a neutrophil targeting ligand, sialic acid. SPCFe/siP effectively bind to neutrophils via sialic acid-based targeting pathway, and neutrophils containing SPCFe/siP serve as Trojan horses to migrate across BBB for improved delivery efficacy into orthotopic glioma sites. Upon irradiation by ultrasound (US), the semiconducting polymers produce 1O2 to destroy 1O2-cleavable nanocarriers for precise on-demand releases of Fe3O4 nanoparticles and PD-L1 siRNA, in which, Fe3O4 nanoparticles induce ferroptosis and subsequent immunogenic cell death (ICD), and PD-L1 siRNA downregulated the expression of PD-L1 for tumor cells, allowing for sono-activatable ferroptosis-immunotherapy. A strong immunological effect is formed, leading to noteworthy restriction of orthotopic glioma tumor growth and improvement of mouse survival. This study provides a neutrophil-targeting nanosystem with efficient brain delivery and activatable therapeutic action for treatment of orthotopic glioma.

HER4 Affects Sensitivity to Tamoxifen and Abemaciclib in Luminal Breast Cancer Cells and Restricts Tumor Growth in MCF-7-Based Humanized Tumor Mice.

The impact of the HER4 receptor on the growth and treatment of estrogen receptor-positive breast cancer is widely uncertain. Using CRISPR/Cas9 technology, we generated stable HER4 knockout variants derived from the HER4-positive MCF-7, T-47D, and ZR-75-1 breast cancer cell lines. We investigated tumor cell proliferation as well as the cellular and molecular mechanisms of tamoxifen, abemaciclib, AMG232, and NRG1 treatments as a function of HER4 in vitro. HER4 differentially affects the cellular response to tamoxifen and abemaciclib treatment. Most conspicuous is the increased sensitivity of MCF-7 in vitro upon HER4 knockout and the inhibition of cell proliferation by NRG1. Additionally, we assessed tumor growth and immunological effects as responses to tamoxifen and abemaciclib therapy in humanized tumor mice (HTM) based on MCF-7 HER4-wildtype and the corresponding HER4-knockout cells. Without any treatment, the enhanced MCF-7 tumor growth in HTM upon HER4 knockout suggests a tumor-suppressive effect of HER4 under preclinical but human-like conditions. This phenomenon is associated with an increased HER2 expression in MCF-7 in vivo. Independent of HER4, abemaciclib and tamoxifen treatment considerably inhibited tumor growth in these mice. However, abemaciclib-treated hormone receptor-positive breast cancer patients with tumor-associated mdm2 gene copy gains or pronounced HER4 expression showed a reduced event-free survival. Evidently, the presence of HER4 affects the efficacy of tamoxifen and abemaciclib treatment in different estrogen receptor-positive breast cancer cells, even to different extents, and is associated with unfavorable outcomes in abemaciclib-treated patients.

Integrated network pharmacology and experimental verification to reveal the role of Shezhi Huangling Decoction against glioma by inactivating PI3K/Akt-HIF1A axis

Shezhi Huangling Decoction (SHD) has been proven clinically effective in regulating metabolic and immune homeostasis in the treatment of glioma. The investigation aimed to deconstruct the active constituents and mechanisms of SHD. Effects of SHD on malignant characteristics of HS683 and KNS89 cells have been investigated by CCK-8, clone formation, flow cytometry, and Transwell assays. A mouse xenograft model was established to assess the effect of SHD or SHD + temozolomide (TMZ) in vivo. A total of 461 constituents were found from SHD in UPLC/Q-TOF-MS/MS analysis. Functional enrichment analysis showed that pathway in cancer, proteoglycans in cancer, regulation of epithelial cell proliferation, inflammation/immune, gliogenesis, brain development, cell adhesion, and autophagy could participate in the treatment of SHD. Additionally, 9 hub genes (AKT1, TP53, CTNNB1, STAT3, EGFR, VEGFA, PIK3CA, ERBB2, and HIF1A) were identified as hub genes. Moreover, we found that SHD may greatly reduce the migration and accelerate apoptosis of HS683 and KNS89 cells. Additionally, SHD coordinates TMZ to restrict tumor growth were found in the mice. Our results suggest that the malignant behaviors of glioma cells are suppressed by SHD and the mechanism may be closing on the inhibition of the PI3K/Akt-HIF1A axis. SHD may serve as a synergistic therapeutic choice for TMZ to suppress glioblastoma growth.

BAG6 restricts pancreatic cancer progression by suppressing the release of IL33-presenting extracellular vesicles and the activation of mast cells

Recent studies reveal a critical role of tumor cell-released extracellular vesicles (EVs) in pancreatic cancer (PC) progression. However, driver genes that direct EV function, the EV-recipient cells, and their cellular response to EV uptake remain to be identified. Therefore, we studied the role of Bcl-2-associated-anthanogene 6 (BAG6), a regulator of EV biogenesis for cancer progression. We used a Cre recombinase/LoxP-based reporter system in combination with single-cell RNA sequencing to monitor in vivo EV uptake and tumor microenvironment (TME) changes in mouse models for pancreatic ductal adenocarcinoma (PDAC) in a Bag6 pro- or deficient background. In vivo data were validated using mouse and human organoids and patient samples. Our data demonstrated that Bag6-deficient subcutaneous and orthotopic PDAC tumors accelerated tumor growth dependent on EV release. Mechanistically, this was attributed to mast cell (MC) activation via EV-associated IL33. Activated MCs promoted tumor cell proliferation and altered the composition of the TME affecting fibroblast polarization and immune cell infiltration. Tumor cell proliferation and fibroblast polarization were mediated via the MC secretome containing high levels of PDGF and CD73. Patients with high BAG6 gene expression and high protein plasma level have a longer overall survival indicating clinical relevance. The current study revealed a so far unknown tumor-suppressing activity of BAG6 in PDAC. Bag6-deficiency allowed the release of EV-associated IL33 which modulate the TME via MC activation promoting aggressive tumor growth. MC depletion using imatinib diminished tumor growth providing a scientific rationale to consider imatinib for patients stratified with low BAG6 expression and high MC infiltration.EVs derived from BAG6-deficient pancreatic cancer cells induce MC activation via IL33/Il1rl1. The secretome of activated MCs induces tumor proliferation and changes in the TME, particularly shifting fibroblasts into an inflammatory cancer-associated fibroblast (iCAF) phenotype. Blocking EVs or depleting MCs restricts tumor growth.

Senescent CAFs Mediate Immunosuppression and Drive Breast Cancer Progression.

The tumor microenvironment (TME) profoundly influences tumorigenesis, with gene expression in the breast TME capable of predicting clinical outcomes. The TME is complex and includes distinct cancer-associated fibroblast (CAF) subtypes whose contribution to tumorigenesis remains unclear. Here, we identify a subset of myofibroblast CAFs (myCAF) that are senescent (senCAF) in mouse and human breast tumors. Utilizing the MMTV-PyMT;INK-ATTAC (INK) mouse model, we found that senCAF-secreted extracellular matrix specifically limits natural killer (NK) cell cytotoxicity to promote tumor growth. Genetic or pharmacologic senCAF elimination unleashes NK cell killing, restricting tumor growth. Finally, we show that senCAFs are present in HER2+, ER+, and triple-negative breast cancer and in ductal carcinoma in situ (DCIS) where they predict tumor recurrence. Together, these findings demonstrate that senCAFs are potently tumor promoting and raise the possibility that targeting them by senolytic therapy could restrain breast cancer development. Significance: senCAFs limit NK cell-mediated killing, thereby contributing to breast cancer progression. Thus, targeting senCAFs could be a clinically viable approach to limit tumor progression. See related article by Belle et al., p. 1324.

Abstract LB358: Program and epigenetic control of stemness and exhaustion of tumor infiltrating CD8+ T lymphocyte

Abstract Tumor infiltrating CD8+ T lymphocytes (TILs) develop a state of exhaustion, become terminally exhausted (Ttex) and fail to control tumor growth through cytolytic activity. At an early stage, however, progenitors of exhausted (pTex) TILs are renewable and still reprogrammable, and can generate efficient cytolytic effector cells. pTex highly express stemness program genes. There is a high interest in understanding the mechanisms that control stemness and exhaustion programs of TILs. In the current study we investigated the consequences of the removal of the transcription factor (TF) BCL11B in TILs on the control of the stemness and exhaustion programs, their epigenetics landscape, and the impact on the pTex versus Ttex TIL status. Using scRNAseq, bulk RNAseq and epigenomics approaches, we positioned BCL11B upstream of essential TFs of the stemness and exhaustion programs, as well as of the cytolytic activity program. BCL11B-/- CD8+ TILs have increased stemness and elevated effector program, but reduced exhaustion, and they promoted a superior response compared to WT TILs, restricting tumor growth. Importantly, evaluation of BCL11B KO signature in patients with metastatic melanoma treated with check point inhibitors, show a more favorable response and survival in the patients with enriched BCL11B KO TIL signature. Thus these results indicate that BCL11B constitutes a promising target for therapeutic intervention in cancer cell therapies to sustain stemness, cytolytic activity and reduce exhaustion. Citation Format: Dorina Avram, Timothy Shaw, Shari Pilon-Thomas, Leonardo Silvane, Tomas Zelenka. Program and epigenetic control of stemness and exhaustion of tumor infiltrating CD8+ T lymphocyte [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB358.

Abstract 2972: Senescent macrophages drive tumorigenesis by limiting antitumor immunity

Abstract A big challenge in oncology is tumor heterogeneity, as the same type of tumor can manifest differently across patients. Our current cancer therapies focus on targeting malignant cells without considering how the tumor microenvironment influence tumorigenesis or changes in response to treatment. Therefore, identifying effective therapies that restrict tumor growth and progression while restoring optimal tissue and organ function is imperative. Here, we propose a potential strategy to delay the frequency of lung tumorigenesis and reduce progression by selectively targeting tumor-promoting senescent cells that arise with advancing age, prolonging antitumor immunity. Using lung tumor-prone mice, we found that senescent cells, specifically senescent alveolar macrophages, accumulate early in hyperplastic lesions. Mechanistically, these macrophages upregulate the cell cycle regulator p16Ink4a; express the cell surface protein CXCR1; they are distinct from other established subsets; are sensitive to senolytic interventions; have a tumor-promoting secretome, including SPP1; and express immunosuppressive factors that modulate the antitumor immune response. Selective clearance of senescent macrophages attenuates adenoma development, indicating they, at least in part, promote tumorigenesis. Importantly, we observed alveolar macrophages with these properties accumulating in treatment-naive human early-stage lung adenocarcinoma in situ, indicating that the cellular senescence program in macrophages is a conserved etiology. We also found that senescent alveolar macrophages accumulate in otherwise naturally aged normal mouse lungs and their persistence correlates with increased inflammation. Collectively, our findings suggest that targeting senescent macrophages may constitute a potential therapeutic intervention to postpone or attenuate lung cancer during the early stages of the disease. Citation Format: Luis I. Prieto. Senescent macrophages drive tumorigenesis by limiting antitumor 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 2972.

Abstract 6749: A dendritic cell targeted nanosystem to overcome immune suppression and enhance the efficacy of the standard of care for pancreatic cancer

Abstract The development of novel therapies for pancreatic ductal adenocarcinoma (PDAC) remains an urgent unmet medical need, as it was proven to be refractory to most conventional anti-neoplastic therapies. PDAC is characterized by highly dense stroma, immunosuppressive tumor microenvironment (TME), high resistance to chemotherapy, and poor presentation of tumor-associated antigens (TAA) by dendritic cells (DC), which results in low immune cell infiltration to the tumor site. To that end, we designed a DC-targeted nanovaccine (NV) containing PDAC TAA and TLR agonists to modulate the PDAC immune-microenvironment. In recent years, the combination of immunotherapy with chemotherapy has been explored for PDAC therapy to improve efficacy. Therefore, we demonstrate the effect of our NV on the anti-tumor immune-mediated response in PDAC-bearing mice, alone and in combination with Gemcitabine and Nab-Paclitaxel (Gem/NabP). Our DC-targeted NV was formulated by the double emulsion method and loaded with PDAC’s TAA and immune potentiators. We conjugated the NV to a mannose moiety as a targeting moiety for the mannose receptor expressed on DC to increase the NV uptake, which resulted in the enhanced presentation of the encapsulated TAA. Followed by physicochemical characterization and evaluation of preclinical safety of the NV, the stimulation of T cell-specific response against PDAC tumor was assessed in vivo and ex vivo. The NV induced significant changes in PDAC’s TME, such as increased CD8+ T cells, decreased CD4+ T regulatory cells, and induced memory immunity in the tumor site. The combination of NV and Gem/NabP inhibited tumor growth and prolonged survival compared to mice treated with Gem/NabP alone. This could also be related to the immunogenic cell death effect caused by the chemotherapies. In addition to our mice model of PDAC, we also established a patient-derived model, in which we generate 3D-spheroids from the patient’s tumor and activate PBMCs with our NV from the same patient. This unique 3D model enables us to evaluate ex vivo the NV effect in a more clinically relevant manner. The NV proposed herein could induce a strong antigen-specific immune response against PDAC with restricted tumor growth while re-shaping PDAC immunosuppressive TME. Furthermore, our 3D patient-derived PDAC model allows us to assess the ability of our NV to generate specific immune responses in patients and to test other possible drug combinations predicting the clinical outcome. Citation Format: Ron Kleiner, Daniella Vaskovich-Koubi, Rita Acúrcio, Barbara Carreira, Helena Florindo, Ronit Satchi-Fainaro. A dendritic cell targeted nanosystem to overcome immune suppression and enhance the efficacy of the standard of care for 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 6749.

An IRF2-Expressing Oncolytic Virus Changes the Susceptibility of Tumor Cells to Antitumor T Cells and Promotes Tumor Clearance.

IFN regulatory factor 1 (IRF1) can promote antitumor immunity. However, we have shown previously that in the tumor cell, IRF1 can promote tumor growth, and IRF1-deficient tumor cells exhibit severely restricted tumor growth in several syngeneic mouse tumor models. Here, we investigate the potential of functionally modulating IRF1 to reduce tumor progression and prolong survival. Using inducible IRF1 expression, we established that it is possible to regulate IRF1 expression to modulate tumor progression in established B16-F10 tumors. Expression of IRF2, which is a functional antagonist of IRF1, downregulated IFNγ-induced expression of inhibitory ligands, upregulated MHC-related molecules, and slowed tumor growth and extended survival. We characterized the functional domain(s) of IRF2 needed for this antitumor activity, showing that a full-length IRF2 was required for its antitumor functions. Finally, using an oncolytic vaccinia virus as a delivery platform, we showed that IRF2-expressing vaccinia virus suppressed tumor progression and prolonged survival in multiple tumor models. These results suggest the potency of targeting IRF1 and using IRF2 to modulate immunotherapy.

Abstract 626: EGFL6 induced HER2-HER3 signaling controls accurate centrosome deposition of activated ERK and mitotic spindle formation in ovarian cancer cells

Abstract Epidermal growth factor EGF-like domain multiple-6 (EGFL6) is highly expressed in high grade serous ovarian cancer (HGSOC) cells and ovarian tumor vasculature. EGFL6 acts on tumor cells to drive tumor cell proliferation and migration. To better understand EGFL6 signaling and develop therapeutic strategies to target EGFL6 signaling in HGSOC, we evaluated phosphorylation of putative EGFL6 receptors and their downstream signaling. We demonstrated that EGFL6 induced phosphorylation and activation of ERBB/HER family of receptors; EGFL6 treatment of ovarian cancer cells led to rapid and transient phosphorylation of EGFR while inducing prolonged activation of both HER2 and HER3, with subsequent phosphorylation of ERK. Interestingly, we found that in EGFL6 stimulated ovarian cancer cells undergoing mitosis, pERK localized to the centrosome and the contractile ring. EGFL6 neutralizing antibodies reduce ERK phosphorylation and resulted in pERK being aberrantly localized. This resulted in altered mitotic spindle alignment and an increased number of cells undergoing mitotic catastrophe. Furthermore, combination anti-EGFL6 therapy with the pan-EGFR receptor inhibitor neratinib, compared to either therapy alone, led to an increase in aberrant pERK localization and cancer cell death in vitro. Consistent with these findings, dual anti-EGFL6 and neratinib therapy significantly restricted tumor growth in vivo, resulting in increased tumor cell death and a reduction in angiogenesis. Combined our data identify an unexplored role for pERK at the centrosome and suggest that dual targeting of the EGFL6/HER signaling axis maybe an effective therapeutic strategy in ovarian cancer. Citation Format: Shoumei Bai, Navneet Gupta, Qi Jiang, Ronald J. Buckanovich. EGFL6 induced HER2-HER3 signaling controls accurate centrosome deposition of activated ERK and mitotic spindle formation in ovarian cancer cells [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 626.

Abstract 6346: IgG engineered to target PIGR-mediated transcytosis specifically targets intracellular oncoproteins and abrogated tumor growth

Abstract Despite their long half-life, therapeutic antibodies are considered ineffective against intracellular antigens due to their perceived inability to penetrate epithelial cells. Using recombinant antibodies targeting common mutations in oncogenes, we have demonstrated that dimeric IgA, but not the same antibody on an IgG backbone, penetrates human epithelial cancer cells through PIGR-dependent directional transcytosis, specifically neutralizing mutated oncodrivers and expelling antigens outside the cell, bound to secretory IgA. Accordingly, targeting of KRASG12D abrogated tumor cell proliferation in cell culture assays. In vivo, KRASG12D-specific dIgA1 limited the growth of RASG12D-mutated ovarian and lung carcinomas, including in syngeneic tumor-bearing immunocompetent mice. Moreover, dIgA targeting of KRASG12D restricted tumor growth more effectively than small-molecule KRASG12D inhibitors, supporting the potential of this approach for the treatment of human cancers. Since producing dimeric IgA is more challenging than producing monomeric IgG, and because the half-life of IgA is shorter (4-7 days) than IgG (21 days), we have developed a new approach combining KRASG12D specific IgG with a peptide that could join PIGR and penetrates tumor cells through transcytosis, that showed the same effect than IgA controlling tumor growth. Our results provide a rationale for developing modified IgG cell-penetrating antibodies to effectively target common mutations in intracellular oncogenes that drive many aggressive and frequent human cancers. In addition, further experiments suggest that these antibodies could be effectively used to target tumors that have become resistant to existing KRAS inhibitors. Citation Format: Carmen Maria Anadon Galindo, Luis U. Lopez-Bailon, Ricardo A. Chaurio, Jessica A. Mine, Noah E. Plappert, Jose R. Conejo-Garcia. IgG engineered to target PIGR-mediated transcytosis specifically targets intracellular oncoproteins and abrogated tumor growth [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 6346.

Abstract 3917: A CXCR4 partial agonist TFF2-MSA improves anti-PD-1 immunotherapy in advanced gastric cancer by selectively targeting PMN-MDSC

Abstract Introduction: Advanced gastric cancer poses a challenge for PD-1 immunotherapy due in part to the prevalence of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs). PMN-MDSCs are mostly immature granulocytes but coexist with mature neutrophils, complicating their precise targeting. While PMN-MDSCs highly express CXCR4, recent clinical trials suggest that CXCR4 antagonists may provide limited additive efficacy to PD-1 blockade. This study explored the efficacy of a secreted CXCR4 partial agonist, trefoil factor family 2 (TFF2), in the context of anti-PD-1 refractory gastric cancer. Methods: We fused mouse TFF2 with murine serum albumin to generate a novel TFF2-MSA peptide with extended half-life, and evaluated its therapeutic effects with or without anti-PD-1 antibody. As histidine decarboxylase (HDC) is expressed in immature neutrophils, we used the HDC-GFP transgene to track PMN-MDSC in vivo. The HDC-GFP mice received subcutaneous or orthotopic implantation of murine syngeneic gastric cancer cells and subsequent treatments. Additionally, human blood was assessed for both serum TFF2 and immune profiles. Results: The combination of TFF2-MSA plus anti-PD-1 antibody displayed remarkable synergy, boosting intratumoral cytotoxic CD8 T cells by 50-fold, leading to tumor regression or eradication, 80% reduction of distant metastasis and 2-fold extension of mouse survival. The immunosuppressive HDC-GFP+ PMN-MDSCs expressed the highest level of CXCR4 among immune cells, and TFF2-MSA treatment systematically reduced HDC-GFP+ PMN-MDSCs in the tumor, blood, spleen and their myeloid progenitors in the bone marrow. In contrast, CXCR4 antagonist AMD3100 in combination with anti-PD-1 failed to restrict tumor growth or PMN-MDSCs. Further single-cell RNA-seq and functional assays revealed that combination of TFF2-MSA plus anti-PD-1 induced a skewing of remaining tumor HDC-GFP+PMN-MDSC compositions from highly immature CD300ld+ subsets to less immature subsets expressing interferon-stimulated genes, accompanied by reduced immunosuppression and increased antigen presentation functions. Rather than local reprogramming, this compositional shift stemmed from an IRF1-driven interferon response in splenic HDC-GFP+ PMN-MDSCs. In human, PMN-MDSCs marked by LOX1 significantly expanded in the blood of gastric cancer patients compared to healthy donors. Human LOX1+ PMN-MDSCs showed an inverse correlation with T cell number, activation, proliferation and the serum TFF2 level. Conclusions: TFF2-MSA synergizes with PD-1 blockade by selectively targeting CXCR4high PMN-MDSCs. This study provides a rational for a novel combination therapy of the CXCR4 partial agonist, TFF2-MSA, rather than CXCR4 antagonists, plus PD-1 blockade for treatment of advanced gastric cancer. Citation Format: Jin Qian, Chenkai Ma, Quin T. Waterbury, Christine S. Moon, Xiaofei Zhi, Feijing Wu, Ruhong Tu, Biyun Zheng, Hiroki Kobayashi, Leah B. Zamechek, Ryan H. Moy, Arnold Han, Bruce Daugherty, Seth Lederman, Timothy C. Wang. A CXCR4 partial agonist TFF2-MSA improves anti-PD-1 immunotherapy in advanced gastric cancer by selectively targeting PMN-MDSC [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 3917.