Mouse Model Of Ovarian Cancer Research Articles

Tasquinimod promotes the sensitivity of ovarian cancer cells to cisplatin by down-regulating the HDAC4/p21 pathway.

To investigate whether Tasquinimod can influence cisplatin resistance in drug-resistant ovarian cancer (OC) cell lines by regulating histone deacetylase 4 (HDAC4) or p21, we explored its effects on the cell cycle, and associated mechanisms. RT-PCR and Western blot analyses, flow cytometry, CCK8 assay, and immunofluorescence were utilized to investigate the effects of Tasquinimod on gene expression, cell cycle, apoptosis, viability, and protein levels in OC cells. The results showed that Tasquinimod inhibited cell viability and promoted apoptosis in SKOV3/DDP (cisplatin) and A2780/DDP cells more effectively than DDP alone. In combination with cisplatin, Tasquinimod further enhanced cell apoptosis and reduced cell viability in these cell lines, an effect that could be reversed following HDAC4 overexpression. Tasquinimod treatment down-regulated HDAC4, Bcl-2, and cyclin D1, and CDK4 expression and up-regulated the cleaved-Caspase-3, and p21 expression in SKOV3/DDP and A2780/ DDP cells. Additionally, Tasquinimod inhibited DDP resistance in OC/DDP cells. These effects were similarly observed in OC mouse models treated with Tasquinimod. In conclusion, Tasquinimod can improve OC cells' sensitivity to DDP by down-regulating the HDAC4/p21 axis, offering insights into potential strategies for overcoming cisplatin resistance in OC.

Generation of an organoid model of a STIC lesion from a MADM mouse model for premalignant ovarian cancer

Generation of an organoid model of a STIC lesion from a MADM mouse model for premalignant ovarian cancer

TLR Agonist Nano Immune Therapy Clears Peritoneal and Systemic Ovarian Cancer.

Intraperitoneal (IP) administration of immunogenic mesoporous silica nanoparticles (iMSN) in a mouse model of metastatic ovarian cancer promotes the development of tumor-specific CD8+ T cells and protective immunity. IP delivery of iMSN functionalized with the Toll-like receptor (TLR) agonists polyethyleneimine (PEI), CpG oligonucleotide, and monophosphoryl lipid A (MPLA) stimulated rapid uptake by all peritoneal myeloid subsets. Myeloid cells quickly transported iMSN to milky spots and fat-associated lymphoid clusters (FALCs) present in tumor-burdened adipose tissues, leading to a reduction in suppressive T cells and an increase in activated memory T cells. Two doses of iMSN cleared or reduced ovarian and colorectal cancer and protected against future tumor engraftment. In contrast, subcutaneous (SC) and intravenous (IV) delivery of iMSN were without therapeutic effect in mice with peritoneal metastases, supporting the need for activation of regional immune cells. Remarkably, intraperitoneal delivery of iMSN cleared subcutaneously implanted ovarian cancer, supporting homing of antigen specific T cells to extraperitoneal tumor sites.

Mitochondrial-targeted plastoquinone therapy ameliorates early onset muscle weakness that precedes ovarian cancer cachexia in mice.

Cancer cachexia, and the related loss of muscle and strength, worsens quality of life and lowers overall survival. Recently, a novel 'pre-atrophy' muscle weakness was identified during early-stage cancer. While mitochondrial stress responses are associated with early-stage pre-atrophy weakness, a causal relationship has not been established. Using a robust mouse model of metastatic epithelial ovarian cancer (EOC)-induced cachexia, we found the well-established mitochondrial-targeted plastoquinone SkQ1 partially prevents pre-atrophy weakness in the diaphragm. Furthermore, SkQ1 improved force production during atrophy without preventing atrophy itself in the tibialis anterior and diaphragm. EOC reduced flexor digitorum brevis (FDB) force production and myoplasmic free calcium ([Ca 2+ ] i ) during contraction in single muscle fibers, both of which were prevented by SkQ1. Remarkably, changes in mitochondrial reactive oxygen species and pyruvate metabolism were heterogeneous across time and between muscle types which highlights a considerable complexity in the relationships between mitochondria and muscle remodeling throughout EOC. These discoveries identify that muscle weakness can occur independent of atrophy throughout EOC in a manner that is linked to improved calcium handling. The findings also demonstrate that mitochondrial-targeted therapies exert a robust effect in preserving muscle force during the early pre-atrophy period and in late-stage EOC once cachexia has become severe.

Vitamin D Significantly Inhibits Carcinogenesis in the Mogp-TAg Mouse Model of Fallopian Tube Ovarian Cancer.

Epidemiological and observational studies suggest that vitamin D has potential for the chemoprevention of ovarian cancer. The anticancer effect of vitamin D in the fallopian tube epithelium (FTE), which is now thought to harbor the precursor cells for high grade ovarian cancer, is not known. The purpose of this study was to investigate whether vitamin D can inhibit carcinogenesis in the mogp-TAg fallopian tube (FT) ovarian cancer mouse model and examine underlying mechanisms. To test this hypothesis, 3 groups of 40 5-week-old female mogp-TAg mice were divided equally into two cohorts of 20 mice, treated with either vehicle (vitamin D solvent) or the active 1,25(OH)2D3 analogue EB1089, delivered via mini-pump or IP injection or cholecalciferol delivered in the feed. The FTs were characterized histologically and pathologically after 3 and 7 weeks of treatment. The effect of vitamin D on cultured human FTE cells was also examined. After 3 weeks, vitamin D, delivered as either cholecalciferol or EB1089 significantly inhibited FT carcinogenesis. After 7 weeks, cholecalciferol significantly reduced p53 signatures, serous tubal epithelial carcinoma, FT cancer, and plasma CA125 while increasing apoptosis in the FTE. EB1089 had no significant effect on FT carcinogenesis at 7 weeks. Cholecalciferol significantly reduced proliferation and increased apoptosis in vitro in p53-altered FTE cells. In conclusion, vitamin D inhibited FT carcinogenesis by clearing cells with p53 alterations. These data suggest that vitamin D has merit for the chemoprevention of fallopian tube/ovarian cancer. The optimal chemopreventive effect may be dependent on the route of vitamin D administration.

Egfl6 promotes ovarian cancer progression by enhancing the immunosuppressive functions of tumor-associated myeloid cells.

Tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) play a critical role in resistance to immunotherapy. In this study, we identified epidermal growth factor-like 6 (Egfl6) as a new regulator of myeloid cell functions. Our analyses indicated that Egfl6, via binding with β3 integrins and activation of p38 and SYK signaling, acts as a chemotactic factor for myeloid cells migration and promotes their differentiation towards an immunosuppressive state. In syngeneic mouse models of ovarian cancer (OvCa), tumor expression of Egfl6 increased the intra-tumoral accumulation of polymorphonuclear (PMN) MDSCs and TAMs and their expression of immunosuppressive factors, including CXCL2, IL-10 and PD-L1. Consistent with this, in an immune 'hot' tumor model, Egfl6 expression eliminated response to a-PD-L1 therapy, while Egfl6 neutralizing antibody decreased the accumulation of tumor-infiltrating CD206+ TAMs and PMN-MDSCs and restored the efficacy of a-PD-L1 therapy. Supporting a role in human tumors, in human OvCa tissue samples, areas of high EGFL6 expression co-localized with myeloid cell infiltration. scRNAseq analyses revealed a correlation between EGFL6 and immune cell expression of immunosuppressive factors. Our data provide mechanistic insights into the onco-immunologic functions of EGFL6 in mediating tumor immune suppression and identified EGFL6 as a potential novel therapeutic target to enhance immunotherapy in OvCa patients.

Lemur tail kinase 3 serves as a predictor of patient outcomes and a target for the treatment of ovarian cancer

Lemur tail kinase 3 (LMTK3) belongs to a family of tyrosine kinases that are known to correlate with tumor grade and patient survival in some cancers. Here, we validated LMTK3 as a specific target and a prognostic biomarker in ovarian cancer (OC). In samples from 204 stage I-II OC patients, immunohistochemical studies revealed a higher cytoplasmic-to-nuclear staining intensity of LMTK3, which correlated with worse overall survival (p<0.001). Efficacy studies utilizing novel LMTK3 binding peptides (LMTK3BPs) showed that all chemosensitive and chemoresistant OC cells were killed without affecting normal cells (p<0.005), with synergistic effects shown following cisplatin and docetaxel treatment. In an orthotopic xenograft mouse model of OC, we saw a 35% tumor reduction in response to intravenous injections of 2mg/kg LMTK3BP given three times a week for 3weeks. Furthermore, invivo safety studies showed no signs of toxicity after LMTK3BP treatment, even at doses as high as 40mg/kg. This study highlights LMTK3 as a predictor of patient clinical outcomes. More importantly, novel LMTK3BPs represent potential safe treatment options, either alone or in combination with therapies, for OC.

Niraparib plays synergistic antitumor effects with NRT in a mouse ovarian cancer model with HRP

ObjectivePARPi offers less clinical benefit for HRP patients compared to HRD patients. PARPi has an immunomodulatory function. NRT therapy targets tumor neoantigens without off-target immune toxicity. We explored the synergy between Niraparib and NRT in enhancing antitumor activity in an HRP ovarian cancer mouse model. MethodsIn the C57BL/6 mouse ID8 ovarian cancer model, the effect of Niraparib on reshaping TIME was evaluated by immune cell infiltration analysis of transcriptomic data. The antitumor effects of Niraparib, NRT, and their combined use were systematically evaluated. To corroborate alterations in TILs, TAMs, and chemokine profiles within the TIME, we employed immunofluorescence imaging and transcriptome sequencing analysis. ResultsNiraparib increased the M1-TAMs and activated CD8+ T cells in tumor tissues of C57BL/6 mice with ID8 ovarian cancer. GSEA showed that gene set associated with immature DC and INFα, cytokines and chemokines were significantly enriched in immune feature, KEGG and GO gene sets, meanwhile CCL5, CXCL9 and CXCL10 play dominant roles together. In the animal trials, combined group had a tumor growth delay compared with Niraparib group (P < 0.01) and control group (P < 0.001), and longer survival compared with the single agent group (P<0.01) . ConclusionsNiraparib could exert immune-reshaping effects, then acts synergistic antitumor effects with NRT in HRP ovarian cancer model. Our findings provide new ideas and rationale for combined immunotherapy in HRP ovarian cancer.

Gut-derived metabolite 3-methylxanthine enhances cisplatin-induced apoptosis via dopamine receptor D1 in a mouse model of ovarian cancer.

Platinum-based chemotherapy failure represents a significant challenge in the management of ovarian cancer (OC) and contributes to disease recurrence and poor prognosis. Recent studies have shed light on the involvement of the gut microbiota in modulating anticancer treatments. However, the precise underlying mechanisms, by which gut microbiota regulates the response to platinum-based therapy, remain unclear. Here, we investigated the role of gut microbiota on the anticancer response of cisplatin and its underlying mechanisms. Our results demonstrate a substantial improvement in the anticancer efficacy of cisplatin following antibiotic-induced perturbation of the gut microbiota in OC-bearing mice. 16S rRNA sequencing showed a pronounced alteration in the composition of the gut microbiome in the cecum contents following exposure to cisplatin. Through metabolomic analysis, we identified distinct metabolic profiles in the antibiotic-treated group, with a notable enrichment of the gut-derived metabolite 3-methylxanthine in antibiotic-treated mice. Next, we employed a strategy combining transcriptome analysis and chemical-protein interaction network databases. We identified metabolites that shared structural similarity with 3-methylxanthine, which interacted with genes enriched in cancer-related pathways. It is identified that 3-methylxanthinesignificantly enhances the effectiveness of cisplatin by promoting apoptosis both in vivo and in vitro. Importantly, through integrative multiomics analyses, we elucidated the mechanistic basis of this enhanced apoptosis, revealing a dopamine receptor D1-dependent pathway mediated by 3-methylxanthine. This study elucidated the mechanism by which gut-derived metabolite 3-methylxanthine mediated cisplatin-induced apoptosis. Our findings highlight the potential translational significance of 3-methylxanthine as a promising adjuvant in conjunction with cisplatin, aiming to improve treatment outcomes for OC patients.IMPORTANCEThe precise correlation between the gut microbiota and the anticancer effect of cisplatin in OC remains inadequately understood. Our investigation has revealed that manipulation of the gut microbiota via the administration of antibiotics amplifies the efficacy of cisplatin through the facilitation of apoptosis in OC-bearing mice. Metabolomic analysis has demonstrated that the cecum content from antibiotic-treated mice exhibits an increase in the levels of 3-methylxanthine, which has been shown to potentially enhance the therapeutic effectiveness of cisplatin by an integrated multiomic analysis. This enhancement appears to be attributable to the promotion of cisplatin-induced apoptosis, with 3-methylxanthine potentially exerting its influence via the dopamine receptor D1-dependent pathway. These findings significantly contribute to our comprehension of the impact of the gut microbiota on the anticancer therapy in OC. Notably, the involvement of 3-methylxanthine suggests its prospective utility as a supplementary component for augmenting treatment outcomes in patients afflicted with ovarian cancer.

Enhancing ovarian cancer treatment with maleimide-modified Pt(IV) prodrug nanoparticles

The limitations of platinum in ovarian cancer therapy, such as poor solubility and significant side effects, often lead to suboptimal therapeutic outcome and mortality. In this study, we have developed a novel approach utilizing biodegradable polymeric nanoparticles as a drug delivery system (NDDS), loaded with advanced platinum (IV) (Pt(IV)) prodrugs. A key feature of our approach is the enhancement of nanoparticles with maleimide, a modification hypothesized to significantly boost tumor tissue accumulation. When tested in mouse models of orthotopic and peritoneal metastasis ovarian cancer, these maleimide-modified nanoparticles are anticipated to show preferential accumulation in tumor tissues, enhancing therapeutic efficiency and minimizing systemic drug exposure. Our findings demonstrate that the maleimide-modified Pt(IV)-loaded NDDSs significantly reduce tumor burden in comparison to traditional cisplatin therapy, while simultaneously reducing adverse side effects. This leads to markedly improved survival rates in models of peritoneal metastasis ovarian cancer, offering a promising new direction in the treatment of this challenging disease.

Combining EHMT and PARP Inhibition: A Strategy to Diminish Therapy-Resistant Ovarian Cancer Tumor Growth while Stimulating Immune Activation.

Despite the success of Poly-ADP-ribose polymerase inhibitors (PARPi) in the clinic, high rates of resistance to PARPi presents a challenge in the treatment of ovarian cancer, thus it is imperative to find therapeutic strategies to combat PARPi resistance. Here, we demonstrate that inhibition of epigenetic modifiers Euchromatic histone lysine methyltransferases 1/2 (EHMT1/2) reduces the growth of multiple PARPi-resistant ovarian cancer cell lines and tumor growth in a PARPi-resistant mouse model of ovarian cancer. We found that combinatory EHMT and PARP inhibition increases immunostimulatory dsRNA formation and elicits several immune signaling pathways in vitro. Using epigenomic profiling and transcriptomics, we found that EHMT2 is bound to transposable elements, and that EHMT inhibition leads to genome-wide epigenetic and transcriptional derepression of transposable elements. We validated EHMT-mediated activation of immune signaling and upregulation of transposable element transcripts in patient-derived, therapy-naïve, primary ovarian tumors, suggesting potential efficacy in PARPi-sensitive disease as well. Importantly, using multispectral immunohistochemistry, we discovered that combinatory therapy increased CD8 T cell activity in the tumor microenvironment of the same patient-derived tissues. In a PARPi-resistant syngeneic murine model, EHMT and PARP inhibition combination inhibited tumor progression and increased Granzyme B+ cells in the tumor. Together, our results provide evidence that combinatory EHMT and PARP inhibition stimulates a cell autologous immune response in vitro, is an effective therapy to reduce PARPi resistant ovarian tumor growth in vivo, and promotes anti-tumor immunity activity in the tumor microenvironment of patient-derived ex vivo tissues of ovarian cancer.

Synergistic effects of Smac mimetic APG-1387 with anti-PD-1 antibody are attributed to increased CD3 + NK1.1 + cell recruitment secondary to induction of cytokines from tumor cells

BackgroundImmune checkpoint inhibitors are approved for the treatment of various tumors, but the response rate is not satisfactory in certain malignancies. Inhibitor of apoptosis proteins (IAP) ubiquitin-E3 ligase activity is involved in the regulation of immune responses. APG-1387 is a novel second mitochondria-derived activator of caspase (Smac) mimetic IAP inhibitor. The aim of this study was to explore the synergistic effect of APG-1387 when combined with anti-PD-1 antibody in a preclinical setting.MethodsWe utilized syngeneic mouse models of ovarian cancer (ID8), colon cancer (MC38), malignant melanoma (B16), and liver cancer (Hepa1-6) to assess the combination effect of APG-1387 and anti-PD-1 antibody, including immune-related factors, tumor growth, and survival. MSD V-PLEX validated assays were used to measure in vitro and in vivo cytokine release.ResultsIn ID8 ovarian cancer and MC38 colon cancer models, APG-1387 and anti-PD1 antibody had synergistic antitumor effects. In the MC38 model, the combination of APG-1387 and anti-PD-1 antibody significantly inhibited tumor growth (P < 0.0001) and increased the survival rate of tumor-bearing animals (P < 0.001). Moreover, we found that APG-1387 upregulated tumor-infiltrating CD3 + NK1.1 + cells by nearly 2-fold, by promoting tumor cell secretion of IL-12. Blocking IL-12 secretion abrogated the synergistic effects of APG-1387 and anti-PD-1 antibody in both MC38 and ID8 models.ConclusionsAPG-1387 has the potential to turn “cold tumors” into hot ones by recruiting more CD3 + NK1.1 + cells into certain tumors. Based on these and other data, the safety and therapeutic effect of this combination will be investigated in a phase 1/2 trial in patients with advanced solid tumors or hematologic malignancies (NCT03386526).Graphic abstract

In Vitro and In Vivo Evaluation of the Effects of Drug 2c and Derivatives on Ovarian Cancer Cells

Background: The identification of novel therapeutic strategies for ovarian cancer (OC), the most lethal gynecological neoplasm, is of utmost urgency. Here, we have tested the effectiveness of the compound 2c (4-hydroxy-2,6-bis(4-nitrobenzylidene)cyclohexanone 2). 2c interferes with the cysteine-dependent deubiquitinating enzyme (DUB) UCHL5, thus affecting the ubiquitin-proteasome-dependent degradation of proteins. Methods: 2c phenotypic/molecular effects were studied in two OC 2D/3D culture models and in a mouse xenograft model. Furthermore, we propose an in silico model of 2c interaction with DUB-UCHL5. Finally, we have tested the effect of 2c conjugated to several linkers to generate 2c/derivatives usable for improved drug delivery. Results: 2c effectively impairs the OC cell line and primary tumor cell viability in both 2D and 3D conditions. The effectiveness is confirmed in a xenograft mouse model of OC. We show that 2c impairs proteasome activity and triggers apoptosis, most likely by interacting with DUB-UCHL5. We also propose a mechanism for the interaction with DUB-UCHL5 via an in silico evaluation of the enzyme-inhibitor complex. 2c also reduces cell growth by down-regulating the level of the transcription factor E2F1. Eventually, 2c activity is often retained after the conjugation with linkers. Conclusion: Our data strongly support the potential therapeutic value of 2c/derivatives in OC.

A novel NIR fluorescent probe for enhanced β-galactosidase detection and tumor imaging in ovarian cancer models

The advancement of biological imaging techniques critically depends on the development of novel near-infrared (NIR) fluorescent probes. In this study, we introduce a designed NIR fluorescent probe, NRO-βgal, which exhibits a unique off–on response mechanism to β-galactosidase (β-gal). Emitting a fluorescence peak at a wavelength of 670 nm, NRO-βgal showcases a significant Stokes shift of 85 nm, which is indicative of its efficient energy transfer and minimized background interference. The probe achieves a remarkably low in vitro detection limit of 0.2 U/L and demonstrates a rapid response within 10 min, thereby underscoring its exceptional sensitivity, selectivity, and operational swiftness. Such superior analytical performance broadens the horizon for its application in intricate biological imaging studies. To validate the practical utility of NRO-βgal in bio-imaging, we employed ovarian cancer cell and mouse models, where the probe's efficacy in accurately delineating tumor cells was examined. The results affirm NRO-βgal's capability to provide sharp, high-contrast images of tumor regions, thereby significantly enhancing the precision of surgical tumor resection. Furthermore, the probe's potential for real-time monitoring of enzymatic activity in living tissues underscores its utility as a powerful tool for diagnostics in oncology and beyond.

Abstract 6739: Efficacy and toxicity of microbial mimetic mesoporous silica nanoparticles in a mouse model of ovarian cancer

Abstract Ovarian cancer is predominately left undetected and untreated until the later stages of the disease where it becomes incredibly difficult to treat. Preclinical studies demonstrate that immunotherapy can be highly effective. Our lab has been working on an immunotherapy approach to treat women with ovarian cancer that utilizes mesoporous silica nanoparticles(MSN). MSN that present pathogen-associated molecular patterns (PAMPS) are able to significantly reduce tumor burden in mouse models of serous epithelial ovarian cancer when administered by intraperitoneal injection. These microbial mimetic particles are decorated with polyethyleneimine (PEI), CpG oligonucleotide, and monophosphoryl lipid A (MPLA). When in the presence of antigen presenting cells, they bind to Toll-like receptors (TLR) present on the cell surface and within the endosome. To better understand mechanisms underlying their efficacy, we injected fluorescent MSN-PEI-CpG-MPLA (100 or 500 nm) or unmodified MSN into mice with advanced ovarian cancer. The particles, regardless of the presence of TLR-agonists, were rapidly internalized by myeloid cells, with trafficking almost exclusively to immune clusters located in tumor-burdened adipose tissues when administered by intraperitoneal injection. Conversely, intravenous injection of MSN-PEI-CpG-MPLA led to predominate accumulation in liver, with no particles found in tertiary lymphoid clusters 24 hours post injection. Furthermore, unlike intraperitoneal injection, intravenous injection of MSN-PEI-CpG-MPLA was without therapeutic effect. Currently we are studying MSN safety and the impact of administration route and dose on efficacy and cytotoxicity. In summary, MSN, with and without TLR agonists, are trafficked by myeloid cells to tumor-burdened fat-associated lymphoid clusters when administered by intraperitoneal injection. Intraperitoneal injection of TLR-agonist modified MSN effectively reduces tumor burden in mice with ovarian cancer. Citation Format: Lorel Y. Medina, Rita E. Serda, Benjamin Marwedel, Melanie S. Jun, Josh Adogola. Efficacy and toxicity of microbial mimetic mesoporous silica nanoparticles in a mouse model of ovarian 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 6739.

Abstract 115: Developing uPAR CAR T Cells for High-Grade Serous Ovarian Cancer

Abstract Chimeric Antigen Receptor (CAR) T cells are a modality of immunotherapy that act to eliminate cancer cells by redirecting the cytolytic activity through targeting a protein overexpressed on the surface of the cancer cell. In contrast to move conventional cancer therapies, their anti-cancer activity does not depend on a cancer-specific molecular vulnerability but rather the differential expression of the target antigen on tumor cells compared to normal tissues. We have developed CAR T cells targeting the urokinase plasminogen activator receptor (uPAR), which is overexpressed on senescent cells but not expressed highly in vital organs, to selectively target senescent cells in a range of tissue damage pathologies where they are known to be pathogenic. uPAR is also highly overexpressed in a wide range of cancer types, including pancreatic, kidney, bladder, brain and ovarian carcinomas, respectively, raising the possibility that CAR T cells targeting uPAR may also be effective against cancer. Indeed, leveraging an electroporation-based genetically-engineered mouse model of ovarian cancer, we demonstrate the robust anti-tumor efficacy of murine uPAR CAR T cells in immunocompetent syngeneic mice. Moreover, through an exhaustive functional screening of 37 distinct human uPAR single-chain fragment variants (scFVs), we have successfully identified lead scFVs exhibiting subnanomolar affinity to membrane-anchored uPAR. Significantly, these human uPAR CAR T cells exhibit the capability to eliminate both orthotopic and metastatic human HGSOC xenograft tumors without inducing severe adverse effects. Ongoing efforts encompass the assessment of the long-term safety and toxicity profiles of uPAR CAR T cells utilizing a humanized mouse model platform. Our results provide a strong rationale for developing uPAR CAR T cells as an anticancer strategy relevant to a broad range of tumor types, and provide an avenue for safety profiling of uPAR CAR T cells prior to clinical testing in non-cancer patients harboring senescence-related pathologies. Citation Format: Zeda Zhang, Xin Fang, Yu-jui Ho, Sascha Haubner, Friederike Kogel, Clemens Hinterleitner, Stella Paffenholz, Kevin Chen, Wei Luan, Amanda Kulick, Gertrude Gunset, Andreina Garcia Angus, Jing Zhang, Zijian Xu, Adam Wang, Qingwen Jiang, Elisa de Stanchina, Britta Weigelt, Dmitriy Zamarin, Aveline Filliol, Judith Feucht, Jorge Mansilla-Soto, Corina Amor, Michel Sadelain, Scott Lowe. Developing uPAR CAR T Cells for High-Grade Serous Ovarian 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 115.

Abstract 2035: A Benzenesulfornamide with potential to improve chemoresponse of ovarian cancer through activation of AMPK and immunogenic cell death

Abstract Introduction: Ovarian cancer is a leading cause of death among women globally often characterized by poor prognosis and aggressive tumor growth. The therapeutic outcomes of ovarian cancer patients are limited by the development of acquired chemoresistance and the lack of targeted therapies. This study aimed to understand the mechanism in which a benzenesulfornamide named Y3 enhances the efficacy of chemotherapeutic agents. Y3 was previously identified by our team as an activator of AMPK with the activity to induce immunogenic cell death of ovarian cancer cells. Material and Methods: Patient-derived ovarian cancer cell lines were pretreated with Y3 for 3 h before treatment of carboplatin or paclitaxel. Celltiter Glo assay was performed to determine the impact of Y3 pretreatment on the IC50 values of carboplatin or paclitaxel after 48 h. Apoptosis was evaluated using Annexin VI/PI staining and Caspase 3 activity assays. The role of AMPK pathway was assessed using AMPK siRNAs and western blot. The potential of Y3 to enhance immunogenic cell death induced by carboplatin or paclitaxel was evaluated in a syngeneic mouse model of ovarian cancer using a vaccination assay. The control group mice were vaccinated by subcutaneously injecting mouse ovarian cancer cells treated by carboplatin in vitro for 24 h into the left flank. The test group mice were vaccinated by injecting Y3-carboplatin co-treated cells. One week after vaccination, untreated live cancer cells were injected into the right flank of both groups. Tumor growth was monitored. Results: Ovarian cancer cell lines pretreated with Y3 showed decreased IC50 values for carboplatin and paclitaxel treatments. The apoptotic cell populations stained by Annexin VI were increased in the Y3 pretreated in comparisons with the single treatment groups. Caspase-3 activity validated the results of Annexin VI/PI staining assay. AMPK knockdown by siRNAs effectively reduced the levels of phospho-AMPK that was induced by Y3, which also dampened the Y3-promoted chemotherapeutic effects on ovarian cancer cells. In the in vivo vaccination assay, tumor growth in the right flank was suppressed in the mice vaccinated with Y3-carboplatin co-treated cells to an extend that is more significant than the control group. Conclusion: Y3 pretreatment increased the sensitivity of ovarian cancer cell lines to carboplatin and paclitaxel. The effects of Y3 on ovarian cancer cells depend on the activation of AMPK. Y3 enhances the immunogenicity of carboplatin-treated ovarian cancer cells. Citation Format: Juhyun Kim, Nia Montero, Shefali Sharma, Miranda Mansolf, Kevin Yang, Tobias Hartwich, Yang Yang-Hartwich. A Benzenesulfornamide with potential to improve chemoresponse of ovarian cancer through activation of AMPK and immunogenic cell death [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 2035.

Abstract 1858: Discovery of AT86474, a highly efficacious anti-ROR1 ADC utilizing a proprietary payload

Abstract ROR1 is a pseudo kinase that is involved in the non-canonical Wnt signaling pathway and is highly expressed during early embryonic development. In adult tissues, ROR1 is expressed at very low levels but its increased expression is observed in hematological cancers and a broad range of solid tumors. AT86474 is a highly homogeneous antibody drug conjugate incorporating AxcynCYSTM technology that allows reproducible site-specific conjugation with DAR4 composition greater than 97%. AT86474 utilizes a proprietary payload derived from an FDA approved drug that was optimized in-house for increased potency and with altered PK properties to limit systemic exposure. In vitro, the payload displays broad sub-nanomolar activity across multiple cancer cell lines, including those resistant to paclitaxel, DM1, MMAE and DXd. The payload is conjugated via an enzyme-cleavable linker optimized for solubility, stability, and high drug to antibody ratios. AT86474 uses a humanized and optimized monoclonal antibody that demonstrates selective binding to ROR1-positive cells and subsequent internalization, sub-nanomolar potency in vitro and strong bystander effects. AT86474 was evaluated in a preclinical CDX mouse model of ovarian cancer, where substantial tumor growth inhibition was observed with two weekly doses at as low as 1 mg/kg. As ROR1 over-expression is also observed in many solid tumors, such as pancreatic, gastric, breast and lung cancers, the use of AT86474 can be expanded to benefit a large patient population. Citation Format: Ban Xiong Tan, Xi Yun Zhang, You Xue Wu, Yin Wen Cheng, Shao Jun Liu, Ping Du, Chen Zhong, Bin Zou. Discovery of AT86474, a highly efficacious anti-ROR1 ADC utilizing a proprietary payload [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 1858.

Abstract 6974: Spatial exosome analysis reveals the location heterogeneity of exosomal miRNAs in ovarian cancer patients

Abstract Extracellular vesicles (EVs), including exosomes, are recognized as promising functional tools involved in cancer progression. Although evidence of the functions of EV in cancer biology has been accumulating, optimizing EV isolation is still a major challenge. In ovarian cancer, peritoneal dissemination is a crucial prognostic factor due to the lack of effective treatment, and EVs in malignant ascites play a key role for progression. In this study, we invented cellulose nanofiber (CNF) sheets which enable to capture EVs from approximately 10 μL of biofluids and enabled the analysis of the bioactive molecules included in the EVs (Nature Communications 2023). By attaching CNF sheets to moistened organs, the EVs in trace amounts of ascites were collected, which was sufficient to perform small RNA sequence analyses. In the ovarian cancer mouse model, CNF sheets enabled the detection of cancer-associated miRNAs from the very early phase when the mice did not have apparent ascites, and the EVs from different locations, such as pelvic walls or liver surfaces, had unique miRNA profiles. To confirm the utility of the CNF sheets in cancer patients, we directly collected the EVs on the organ surfaces by the EV attachment method during surgery under appropriate ethical institutional approval with individual consent. EVs were collected from the pelvic peritoneum, omentum, liver surface, or tumor surface, and the miRNA profiling demonstrated each location formed unique clusters. Notably, several tumor-suppressive miRNAs have been identified in liver surface EVs, such as miR-122-3p, and this is consistent with actual ovarian cancer cell progression, which tends to metastasize to the diaphragm rather than to the liver surface. In addition, the trajectory analysis revealed that the pattern of connection in each site was different between patients with localized and advanced disease. We identified ten miRNAs were high in tumors and in EVs from tumor rupture sites, and the level of each miRNA decreased with distance from the primary tumors. Among ten miRNAs, hsa-miR-200b-3p and hsa-miR-429 were confirmed as highly expressed in tumor tissues compared to adjacent normal tissues or benign tumors, and three miRNAs in serum, urine and saliva decreased post-surgery. In summary, spatial CNF sheet analyses in patient bodies identified location-based heterogeneity in EV-miRNA profiles, and the profiles reflected disease conditions. This new method could provide unveiled biological aspects of EVs, and suggest a clinical strategy contributing to cancer diagnosis, staging evaluation, and therapy planning. Citation Format: Akira Yokoi, Kosuke Yoshida, Yusuke Yamamoto, Takao Yasui, Hiroaki Kajiyama. Spatial exosome analysis reveals the location heterogeneity of exosomal miRNAs in ovarian cancer patients [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 6974.

Abstract 4114: AST-201 (pUMVC3-hIGFBP2 N-terminus) demonstrates anti-tumor effect in an ovarian cancer mouse model

Abstract Background: IGFBP2, known to enhance the invasion capacity of ovarian cancer cells, has been suggested that its inhibition could be potentially a treatment strategy of ovarian cancer. AST-201 (pUMVC3-hIGFBP2) is a therapeutic cancer vaccine using a plasmid DNA encoding IGFBP2 N-terminus. In a phase 1 study (NCT01322802) completed, 100 μg AST-201 (intradermal immunization, id) showed not only a significant efficacy by inducing the Th1-cell immunity against IGFBP2 but also safety and tolerability profiles in ovarian cancer patients. The primary objective of this study is to evaluate whether the administration of AST-201 alone and the combination with pembrolizumab could show anti-tumor efficacy and/or synergic effect in the ID8-Luc2 ovarian cancer mouse model. Also, immunological responses were observed as explorative endpoint. Methods: AST-201 (100 μg/animal, id, mixed with mGM-CSF as an immune adjuvant) was immunized to mice (C57BL/6) once a week for a total of 4 times on different days, either alongside pembrolizumab (10 mg/kg, intraperitoneal injection) twice a week for a total of 3 times on different days. Also, AST-201 was immunized was a mono treatment. The efficacy was evaluated by a tumor growth inhibition (TGI) rate at the last day, and immune cell profiling via FACS analysis was conducted with splenocytes and tumor tissues collected at 8 weeks after the first injection. Results: As a primary endpoint, a TGI rate at Day 55 of AST-201 mono treatment was 67%, comparing to a control group (p&amp;lt;0.05). The anti-tumor effect of AST-201 combining with pembrolizumab was better than standard dose pembrolizumab, based on a TGI rate at Day 55 (78% vs 66%, not significant). Immune profiling showed that AST-201 and pembrolizumab combination regimen could inhibit a tumor growth by transforming TME into inflamed-type (‘hot’) form the low immunoreactivity, which was supported by increased CD4+TEM, and CD8+TEM and T helper cells in splenocyte and TIL analysis. Conclusion: A study demonstrated that AST-201 (IGFBP2 cancer vaccine) showed an anti-tumor effect as mono treatment and would be potentially leading to a synergistic effect with a combination regimen of pembrolizumab. Phase 2 randomized-controlled study of AST-201 in ovarian cancer will be initiated under the MRCT strategy (CornerStone-004 study, NCT05794659). Citation Format: Jinback Lim, Jinho Kang, Hyo-Hyun Park, Jin Kyeong Choi, Jee Hyun Choi, Seong-Yong Jang, Min-Ah Kim, Myeong-Kyu Park, Mary L Disis, Eunkyo Joung, Ashley Yongmin Kim, Hun Jung. AST-201 (pUMVC3-hIGFBP2 N-terminus) demonstrates anti-tumor effect in an ovarian cancer mouse model [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 4114.