Orthotopic Transplantation Model Research Articles

Pexidartinib and Immune Checkpoint Inhibitors Combine to Activate Tumor Immunity in a Murine Colorectal Cancer Model by Depleting M2 Macrophages Differentiated by Cancer-Associated Fibroblasts.

Tumor-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs) are known to play supportive roles in tumor development and progression, but their interactions in colorectal cancer (CRC) remain unclear. Here, we investigated the effects of colon-cancer-derived CAFs on TAM differentiation, migration, and tumor immunity, both in vitro and in vivo. When co-cultured with monocytes, CAFs attracted monocytes and induced their differentiation into M2 macrophages. Immunohistology of surgically resected human CRC specimens and orthotopically transplanted mouse tumors revealed a correlation between numbers of CAFs and numbers of M2 macrophages. In a mouse model of CRC orthotopic transplantation, treatment with an inhibitor of the colony-stimulating factor-1 receptor (PLX3397) depleted M2 macrophages and increased CD8-positive T cells infiltrating the tumor nest. While this treatment had a minor effect on tumor growth, combining PLX3397 with anti-PD-1 antibody significantly reduced tumor growth. RNA-seq following combination therapy showed activation of tumor immunity. In summary, CAFs are involved in the induction and mobilization of M2 macrophage differentiation in the CRC tumor immune microenvironment, and the combination of cancer immunotherapy and PLX3397 may represent a novel therapeutic option for CRC.

Glutamine maintains the stability of alveolar structure and function after lung transplantation by inhibiting autophagy

Excessive autophagy may lead to degradation and damage of alveolar epithelial cells after lung transplantation, eventually leading to alveolar epithelial cell loss, affecting the structural integrity and function of alveoli. Glutamine (Gln), a nutritional supplement, regulates autophagy through multiple signaling pathways. In this study, we explored the protective role of Gln on alveolar epithelial cells by inhibiting autophagy. In vivo, a rat orthotopic lung transplant model was carried out to evaluate the therapeutic effect of glutamine. Ischemia/reperfusion (I/R) induced alveolar collapse, edema, epithelial cell apoptosis, and inflammation, which led to a reduction of alveolar physiological function, such as an increase in peak airway pressure, and a decrease in lung compliance and oxygenation index. In comparison, Gln preserved alveolar structure and function by reducing alveolar apoptosis, inflammation, and edema. In vitro, a hypoxia/reoxygenation (H/R) cell model was performed to simulate IR injury on mouse lung epithelial (MLE) cells and human lung bronchus epithelial (Beas-2B) cells. H/R impaired the proliferation of epithelial cells and triggered cell apoptosis. In contrast, Gln normalized cell proliferation and suppressed I/R-induced cell apoptosis. The activation of mTOR and the downregulation of autophagy-related proteins (LC3, Atg5, Beclin1) were observed in Gln-treated lung tissues and alveolar epithelial cells. Both in vivo and in vitro, rapamycin, a classical mTOR inhibitor, reversed the beneficial effects of Gln on alveolar structure and function. Taken together, Glnpreserved alveolar structure and function after lung transplantation by inhibiting autophagy.

Characterization of an orthotopic mouse transplant model reveals early changes in the tumor microenvironment of lung cancer

Characterization of an orthotopic mouse transplant model reveals early changes in the tumor microenvironment of lung cancer

Abstract B024: Development of HM-001 as a therapeutic drug for non-muscle invasive bladder cancer

Abstract HM-001 is a drug containing sodium chlorite as the active ingredient that is being developed as a drug for non-muscle invasive bladder cancer (NMIBC), and is currently undergoing physician-led clinical trials. It has been discovered that sodium chlorite generates radicals in an acidic environment, and phosphatidylserine on the surface of tumor cells acts as a Lewis acid to generate radicals. HM-001, like other anticancer drugs and BCG, is intended to be injected into the bladder, retained, and then excreted. GLP studies using the same administration method has been completed, and no toxic changes have been observed in human trial doses. The efficacy of HM-001 against NMIBC was evaluated using an orthotopic transplantation model of UM-UC-3, a bladder cancer cell line. In the model, cells were transplanted into the bladder of SCID mouse after epithelial removal with trypsin, 600, 800, 1,600, and 3,200 ppm of HM-001 were administered once a week, and the weight of the excised bladder was calculated. After 4 weeks, the tumor weight was calculated and the tumor weight suppression rate in the control group was evaluated. As a result, the medicinal efficacy was confirmed at concentrations of 800ppm or higher. On the other hand, the UM-UC-3 model is a commonly used model, but it mimics CIS (carcinoma in situ) and can only partially mimic NMIBC. That is, other models are needed to evaluate efficacy for low- and high-grade NMIBC other than CIS. Therefore, we established high-grade and low-grade PDX and evaluated the effectiveness of HM-001 against low- and high-grade PDX through ex vivo testing. First, patient-derived tissue was transplanted into SCID mice, allowed to grow, and then removed. After extraction, they were cut into 2 mm3 pieces, exposed to HM-001 at 800, 1600, and 3200 ppm for 2 hours, and then transplanted into SCID mice. As a result of comparing the tumor size after transplantation with the control group, a dose-dependent tumor regression effect was confirmed in high-grade and low-grade PDX. NMIBC is divided into low-, medium-, and high-risk categories, with different treatment methods and drugs used for each. In particular, low-grade forms are restricted to low- and intermediate-risk groups. The results of this study show that HM-001 is effective not only for high-risk (including CIS) NMIBC but also for low- and intermediate-risk (low-grade) NMIBC. Citation Format: Shinji Mima, Monta Sakaki, Noriaki Kiya, Atsunari Kawashima, Norio Nonomura, Chihaya Kakinuma. Development of HM-001 as a therapeutic drug for non-muscle invasive bladder cancer [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2024 May 17-20; Charlotte, NC. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(10_Suppl):Abstract nr B024.

Exogenous Metabolic Modulators Improve Response to Carboplatin in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) lacks targeted therapies, leaving cytotoxic chemotherapy as the current standard treatment. However, chemotherapy resistance remains a major clinical challenge. Increased insulin-like growth factor 1 signaling can potently blunt chemotherapy response, and lysosomal processes including the nutrient scavenging pathway autophagy can enable cancer cells to evade chemotherapy-mediated cell death. Thus, we tested whether inhibition of insulin receptor/insulin-like growth factor 1 receptor with the drug BMS-754807 and/or lysosomal disruption with hydroxychloroquine (HCQ) could sensitize TNBC cells to the chemotherapy drug carboplatin. Using in vitro studies in multiple TNBC cell lines, in concert with in vivo studies employing a murine syngeneic orthotopic transplant model of TNBC, we show that BMS-754807 and HCQ each sensitized TNBC cells and tumors to carboplatin and reveal that exogenous metabolic modulators may work synergistically with carboplatin as indicated by Bliss analysis. Additionally, we demonstrate the lack of overt in vivo toxicity with our combination regimens and, therefore, propose that metabolic targeting of TNBC may be a safe and effective strategy to increase sensitivity to chemotherapy. Thus, we conclude that the use of exogenous metabolic modulators, such as BMS-754807 or HCQ, in combination with chemotherapy warrants additional study as a strategy to improve therapeutic responses in women with TNBC.

Regulatory effect of Yinchenhao decoction on bile acid metabolism to improve the inflammatory microenvironment of hepatocellular carcinoma in mice.

Hepatocellular carcinoma (HCC) is a malignant tumor with extremely high mortality. The tumor microenvironment is the "soil" of its occurrence and development, and the inflammatory microenvironment is an important part of the "soil". Bile acid is closely related to the occurrence of HCC. Bile acid metabolism disorder is not only directly involved in the occurrence and development of HCC but also affects the inflammatory microenvironment of HCC. Yinchenhao decoction, a traditional Chinese medicine formula, can regulate bile acid metabolism and may affect the inflammatory microenvironment of HCC. To determine the effect of Yinchenhao decoction on bile acid metabolism in mice with HCC and to explore the possible mechanism by which Yinchenhao decoction improves the inflammatory microenvironment of HCC by regulating bile acid metabolism, we established mice model of orthotopic transplantation of hepatocellular carcinoma. These mice were treated with three doses of Yinchenhao decoction, then liver samples were collected and tested. Yinchenhao decoction can regulate the disorder of bile acid metabolism in liver cancer mice. Besides, it can improve inflammatory reactions, reduce hepatocyte degeneration and necrosis, and even reduce liver weight and the liver index. Taurochenodeoxycholic acid, hyodeoxycholic acid, and taurohyodeoxycholic acid are important molecules in the regulation of the liver inflammatory microenvironment, laying a foundation for the regulation of the liver tumor inflammatory microenvironment based on bile acids. Yinchenhao decoction may improve the inflammatory microenvironment of mice with HCC by ameliorating hepatic bile acid metabolism.

Development of a large animal orthotopic intestinal transplantation model with long-term survival for study of immunologic outcomes.

Intestinal transplantation (ITx) is the last remaining therapy for patients with intestinal failure once parenteral nutrition is no longer an option, however its use is limited by immunological complications, including high rates of rejection and morbidity associated with immunosuppression, such as infection and malignancy. We aimed to develop a large animal model of ITx with which to study the immune response to ITx and to design and test tolerance induction regimens. Learning from prior complications, we developed and progressively improved both surgical methods for the donor and recipient as well as postoperative management strategies. Methods of stoma generation, bowel positioning, vessel preparation, and fluid management were optimized. The immunosuppression strategy mirrored our clinical regimen. As a result of our modifications, results improved from survival less than 1 month to consistent long-term survival with good graft function. We review several techniques that were developed to avoid pitfalls that were encountered, which can be used to optimize outcomes in this model. Achieving long-term survival after swine orthotopic ITx permits immunological analysis and pre-clinical trials in a large animal model of ITx.

Abstract ED03-01: Breaking the Obesity-Breast Cancer Link: Comparing Diet, Drug and Surgical Approaches

Abstract The prevalence of obesity, an established risk and progression factor for at least 15 types of cancer (including breast cancer), continues to rise in the US and many other countries. Lifestyle approaches to weight loss have proven challenging for most people to maintain, and bariatric surgery, while effective, is expensive and has numerous adverse effects. The recent availability of highly effective incretin therapies for weight loss raises several key questions that we will address, including: i) do these agents drive weight loss in obese female mice?; ii) do they reverse obesity-induced metabolic dysregulation?; iii) can they reverse obesity-driven cancer?; iv) how heterogeneous is the response to these agents? We will report our study of the effects of extended (13 weeks) tirzepatide (TZP, a dual GLP1R/GIPR agonist) treatment in obese female mice on weight loss, metabolic hormones, and mammary tumor growth. We found that—similar to reports in the literature using male mice—obese female mice lost >20% body weight by 4 weeks of TZP treatment. Moreover, TZP-induced weight loss was maintained through 13 weeks of treatment by progressively escalating the dose up to 40 nmol/kg. Congruent with reports in male rodents and humans, we found the majority of weight loss in female mice was attributed to loss of adipose tissue, rather than lean mass. The effects of TZP on body weight and composition were associated with reversal of obesity-induced changes in glycemic control and circulating levels of metabolic hormones, particularly leptin, insulin, and IGF-1. TZP also significantly reversed the protumor effects of obesity in our murine E0771 orthotopic transplant model of TNBC.Furthermore, daily 30% calorie restriction, which we previously reported has strong weight loss-inducing, metabolic reprogramming and anticancer effects in multiple mouse models of breast and other cancers, reversed body weight, adiposity, and TNBC tumor growth and altered metabolic hormones to a greater extent than all groups studied, including the never-obese control mice and TZP-treated mice. Citation Format: S. Hursting. Breaking the Obesity-Breast Cancer Link: Comparing Diet, Drug and Surgical Approaches [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr ED03-01.

A modified orthotopic left lung transplantation model in rats

To enhance the operability of the rat orthotopic left lung transplantation model, we implemented several improvements and meticulously detailed the procedure. One hundred and thirty-one healthy male Sprague Dawley rats, weighing between 250 and 300 g, were utilized, with 64 serving as donors, 64 as recipients, and 3 as sham controls. We employed a modified three-cuff technique for the orthotopic left lung transplantation. Notably, our modified perfusion method could prevent donor lung edema, while waist-shaped cuffs minimized suture slippage during anastomosis. Additionally, positioning the recipient rat in a slightly left-elevated supine position during anastomosis reduced tension on the lung hilum, thus mitigating the risk of vascular laceration. The introduction of a unique two-person anastomosis technique significantly reduced operation time and substantially improved success rates. Furthermore, maximizing inflation of donor lungs both during preservation and surgery minimized the occurrence of postoperative atelectasis. Various other procedural refinements contributed to the enhanced operability of our model. Sixty-four rat orthotopic left lung transplantations were performed with only one surgical failure observed. The acquisition time for donor lungs averaged (19 ± 4) minutes, while (11 ± 1) minutes were allocated for donor lung hilum anatomy and cuff installation. Recipient thoracotomy and left lung hilar anatomy before anastomosis required (24 ± 8) minutes, with anastomosis itself taking (31 ± 6) minutes. Remarkably, the survival rate at the 4-h postoperative mark stood at 96.7 %. Even six months post-operation, transplanted left rat lungs continued to exhibit proper inflation and contraction rhythms, displaying signs of chronic pathological changes. In summary, our modified rat model of orthotopic left lung transplantation demonstrates robust operability, significantly reducing surgical duration, improving operation success rates, and enhancing postoperative survival rates. Furthermore, its long-term survival capacity enables the simulation of acute and chronic disease processes following lung transplantation.

Ubiquitin ligase TRIM15 promotes the progression of pancreatic cancer via the upregulation of the IGF2BP2-TLR4 axis

BackgroundThe tripartite motif family, predominantly characterized by its E3 ubiquitin ligase activities, is involved in various cellular processes including signal transduction, apoptosis and autophagy, protein quality control, immune regulation, and carcinogenesis. Tripartite Motif Containing 15 (TRIM15) plays an important role in melanoma progression through extracellular signal-regulated kinase activation; however, data on its role in pancreatic tumors remain lacking. We previously demonstrated that TRIM15 targeted lipid synthesis and metabolism in pancreatic cancer; however, other specific regulatory mechanisms remain elusive. MethodsWe used transcriptomics and proteomics, conducted a series of phenotypic experiments, and used a mouse orthotopic transplantation model to study the specific mechanism of TRIM15 in pancreatic cancer in vitro and in vivo. ResultsTRIM15 overexpression promoted the progression of pancreatic cancer by upregulating the toll-like receptor 4. The TRIM15 binding protein, IGF2BP2, could combine with TLR4 to inhibit its mRNA degradation. Furthermore, the ubiquitin level of IGF2BP2 was positively correlated with TRIM15. ConclusionsTRIM15 could ubiquitinate IGF2BP2 to enhance the function of phase separation and the maintenance of mRNA stability of TLR4. TRIM15 is a potential therapeutic target against pancreatic cancer.

PGRN inhibits CD8+T cell recruitment and promotes breast cancer progression by up-regulating ICAM-1 on TAM

BackgroundTumor microenvironment actually reduces antitumor effect against the immune attack by exclusion of CD8+T cells. Progranulin (PGRN) is a multifunctional growth factor with significant pathological effects in multiple tumors; however, its role in immunity evasion of breast cancer (BCa) is not completely understood.MethodsWe depleted GRN (PGRN gene) genetically in mice or specifically in PY8119 murine BCa cell line, and mouse models of orthotopic or subcutaneous transplantation were used. Chimeric mice-deficient of PGRN (Grn−/−) in bone marrow (BM) compartment was also generated. Association of PGRN expression with chemokine production or BCa development was investigated by histological and immunological assays.ResultsWe found PGRN was involved in exhaustion of cytotoxic CD8+T cell in BCa with the increasing expressions of M2 markers and intercellular cell adhesion molecule-1 (ICAM-1) on macrophages. Specifically, ablation of PGRN in PY8119 cells reduced tumor burden, accompanied by the infiltrating of cytotoxic CD8+T cells into tumor nests. Moreover, our result revealed that blockade of PD-1 in PGRN-depleted tumors exhibited better antitumor effect in vivo and significantly decreased tumor burden.ConclusionThese findings suggest that inhibition of PGRN may act as a potential immune-therapeutic strategy by recovering infiltration of CD8+T cell in BCa tissue and thereby enhancing the response to anti-PD-1 therapy.

Effect of sulfasalazine on ferroptosis during intestinal injury in rats after liver transplantation

Using a rat autologous orthotopic liver transplantation (AOLT) model and liver cold ischemia–reperfusion (I/R)-induced intestinal injury, we clarified whether ferroptosis occurred in rat AOLT cold I/R-induced intestinal injury. Additionally, the role and possible mechanism of the ferroptosis activator sulfasalazine (SAS) in intestinal injury-induced ferroptosis in rats with AOLT liver cold I/R were investigated. Sixty specific pathogen free (SPF)-grade adult male Sprague‒Dawley (SD) rats were randomly divided into 5 groups using the random number table method (n = 12). Six rats were randomly selected at 6 hour (h) and 24 h after I/R. Inferior vena cava blood specimens were collected from the portal vein (PV) opening at 6 h and 24 h. The concentrations of serum malondialdehyde (MDA), serum interleukin 6 (IL-6) were determined by enzyme-linked immunosorbent assay (ELISA). Ileal tissue was obtained from the PV opening in rats in each group at 6 h and 24 h, and ileal tissue sections were observed under light microscopy. The contents of intestinal MDA, superoxide dismutase (SOD), glutathione(GSH), glutathione peroxidase 4 (GPX4), and tissue iron were determined by ELISA, and the expression of GPX4 and the cysteine glutamate reverse transporter light chain protein (xCT) was determined by Western blot. The experimental results show that ferroptosis is involved in the pathophysiological process of intestinal injury induced by cold hepatic ischemia–reperfusion in AOLT rats. In addition, SAS (500 mg/kg) may inhibit the cystine/glutamate antiporters (System Xc¯)/GSH/GPX4 signal axis in intestinal injury induced by cold I/R in rat AOLT liver, or iron overload after reperfusion, causing a massive accumulation of L-ROS and activating cellular ferroptosis, further aggravate the intestinal injury.

Abstract 3329: Development of HM-001 as a therapeutic drug for non-muscle invasive bladder cancer

Abstract HM-001 is a drug containing sodium chlorite as the active ingredient that is being developed as a drug for non-muscle invasive bladder cancer (NMIBC), and is currently undergoing physician-led clinical trials. It has been discovered that sodium chlorite generates radicals in an acidic environment, and phosphatidylserine on the surface of tumor cells acts as a Lewis acid to generate radicals. HM-001, like other anticancer drugs and BCG, is intended to be injected into the bladder, retained, and then excreted. GLP studies using the same administration method has been completed, and no toxic changes have been observed in human trial doses. The efficacy of HM-001 against NMIBC was evaluated using an orthotopic transplantation model of UM-UC-3, a bladder cancer cell line. In the model, cells were transplanted into the bladder of SCID mouse after epithelial removal with trypsin, 600, 800, 1,600, and 3,200 ppm of HM-001 were administered once a week, and the weight of the excised bladder was calculated. After 4 weeks, the tumor weight was calculated and the tumor weight suppression rate in the control group was evaluated. As a result, the medicinal efficacy was confirmed at concentrations of 800ppm or higher. On the other hand, the UM-UC-3 model is a commonly used model, but it mimics CIS (carcinoma in situ) and can only partially mimic NMIBC. That is, other models are needed to evaluate efficacy for low- and high-grade NMIBC other than CIS. Therefore, we established high-grade and low-grade PDX and evaluated the effectiveness of HM-001 against low- and high-grade PDX through ex vivo testing. First, patient-derived tissue was transplanted into SCID mice, allowed to grow, and then removed. After extraction, they were cut into 2 mm3 pieces, exposed to HM-001 at 800, 1600, and 3200 ppm for 2 hours, and then transplanted into SCID mice. As a result of comparing the tumor size after transplantation with the control group, a dose-dependent tumor regression effect was confirmed in high-grade and low-grade PDX. NMIBC is divided into low-, medium-, and high-risk categories, with different treatment methods and drugs used for each. In particular, low-grade forms are restricted to low- and intermediate-risk groups. The results of this study show that HM-001 is effective not only for high-risk (including CIS) NMIBC but also for low- and intermediate-risk (low-grade) NMIBC. Citation Format: Shinji Mima, Monta Sakaki, Noriaki Kiya, Atsunari Kawashima, Norio Nonomura, Chihaya Kakinuma. Development of HM-001 as a therapeutic drug for non-muscle invasive bladder 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 3329.

Abstract 287: Analysis for the role of antigen-presenting cancer-associated fibroblasts in tumor microenvironment of colorectal cancer

Abstract A new subset of cancer associated fibroblasts (CAFs) called antigen presenting CAF (apCAF) was recently identified, and modulation of the tumor immunity might be associated with tumor progression. We examined the markers of apCAF, such as IRF5, HLA-DRA and HLA-DQA1 by bioinformatics analyses of human colorectal cancer (CRC) datasets. The expression of apCAF markers were upregulated in CAFs isolated from human CRCs and liver metastases compared with their normal counterparts. Kaplan-Meir analysis of 172 human CRC samples clarified that the patients with apCAF marker positive expression in the tumor stroma had worse prognosis than that with negative expression. In addition, the origin of apCAFs was reported to be mesothelial cells, therefore, we established cancer-associated mesothelial cells (CAmes) from ascites of human CRC patients with peritoneal dissemination. Consistently, the expression of antigen-presentation markers was highly upregulated in CAmes, however, allo-mixed lymphocyte reaction analysis demonstrated that their stimulating activity of CD4+ T lymphocytes was diminished. In an in vivo study, we applied a rectal orthotopic transplant model with mouse tumor organoid (MTO) to investigate the effect of apCAF on tumor progressions. Using fluorescence-activated cell sorting (FACS), we examined the ratios of apCAF, myCAF, and iCAF in orthotopic rectal tumors. The percentage of apCAF was highest in the 6-week-tumors and the percentage of myCAF was highest in the 9-week-tumors. Interestingly, the percentage of apCAF was higher in liver metastases than in primary tumor, consistent with bioinformatics analysis. The apCAF increased during the stage of tumor growth, and the percentage of myCAF increase in the later stage of tumor progression with fibrosis. In summary, apCAF might be associated with tumor progression in CRC. Citation Format: Yasuhiro Fukui, Hiroaki Kasashima, Zizhou Wang, Ken Yonemitsu, Kishu Kitayama, Yuichiro Miki, Mami Yoshii, Tatsunari Fukuoka, Tatsuro Tamura, Masatsune Shibutani, Takahiro Toyokawa, Hiroaki Tanaka, Shigeru Lee, Masakazu Yashiro, Kiyoshi Maeda. Analysis for the role of antigen-presenting cancer-associated fibroblasts in tumor microenvironment of colorectal 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 287.

Bulk and single-cell RNA sequencing analysis with 101 machine learning combinations reveal neutrophil extracellular trap involvement in hepatic ischemia-reperfusion injury and early allograft dysfunction

BackgroundHepatic ischaemia–reperfusion injury (HIRI) is a major clinical concern during the perioperative period and is closely associated with early allograft dysfunction (EAD), acute rejection (AR) and long-term graft survival. Neutrophil extracellular traps (NETs) are extracellular structures formed by the release of decondensed chromatin and granular proteins following neutrophil stimulation. There is growing evidence that NETs are involved in the progression of various liver transplantation complications, including ischaemia–reperfusion injury (IRI). This study aimed to comprehensively analyse the expression patterns of NET-related genes (NRGs) in HIRI, identify HIRI subtypes with distinct characteristics, and develop a reliable EAD prediction model. MethodsMicroarray, bulk RNA-seq, and single-cell sequencing datasets were obtained from the GEO database. Initially, differentially expressed NRGs (DE-NRGs) were identified using differential gene expression analyses. We then utilised a non-negative matrix factorisation (NMF) algorithm to classify HIRI samples. Subsequently, we employed machine learning algorithms to screen the hub NRGs related to EAD and developed an EAD prediction model based on these hub NRGs. Concurrently, we assessed the expression patterns of hub NRGs at the single-cell level using the HIRI. Additionally, we validated C5AR1 expression and its effect on HIRI and NETs formation in a rat orthotopic liver transplantation (OLT) model. ResultsIn this study, we identified 11 DE-NRGs in the HIRI context. Based on these 11 DE-NRGs, HIRI samples were classified into two distinct clusters. Cluster1 exhibited a low expression of DE-NRGs, minimal neutrophil infiltration, mild inflammation, and a low incidence of EAD. Conversely, Cluster2 displayed the opposite phenotype, with an activated inflammatory subtype and a higher incidence of EAD. Furthermore, an EAD prediction model was developed using the four hub NRGs associated with EAD. Based on risk scores, HIRI samples were classified into high- and low-risk groups. The OLT model confirmed substantial upregulation of C5AR1 expression in the liver tissue, accompanied by increased formation of NETs. Treatment with a C5AR1 antagonist improved liver function, reduced tissue inflammation, and decreased NETs formation. ConclusionsThis study distinguished two apparent HIRI subtypes, established a predictive model for EAD, and validated the effect of C5AR1 on HIRI. These findings provide novel perspectives for the development of advanced clinical strategies to enhance the outcomes of liver transplant recipients.

Abstract B020: A clinically relevant orthotopic endometrial carcinosarcoma mouse model using human patient-derived organoids

Abstract Uterine carcinosarcoma (CS) is a rare but aggressive endometrial malignancy. The incidence of CS has been increasing and is projected to continue to rise. African American women in particular have an increased incidence of CS and overall increased mortality related to endometrial cancer, underscoring known disparities in cancer care across racial and ethnic groups. Compared to other histologic subtypes, CS remains rare and understudied on a molecular and cellular basis, and under-represented in clinical trials. Therefore, current treatment therapies available for CS have been extrapolated from treatments used in other histologies of endometrial cancer, highlighting a significant need for effective treatment targeted at this subtype. Due to this paucity of data surrounding targeted therapies for CS, patients who are diagnosed with this aggressive and lethal cancer tend to have worse outcomes. We have developed a clinically relevant CS murine model by injecting human CS patient-derived organoids (PDO) from diverse ancestries into the endometrium of immunocompromised mice. Tumor progression in the mice was monitored with physical examination, PET/CT scan, contrast enhanced CT scan, ultrasound, and bioluciferase imaging. The tumor was established after three months, and the mice were sacrificed following the experiment. The diagnosis of invasive CS was confirmed by macroscopic and histologic analyses in the orthotopic model. Our orthotopic CS PDO transplantation model has many potential applications for studying tumor biology of CS in the pre-clinical setting. Future directions include trialing the efficacy of standard of care chemotherapy in the orthotopic model. Using this model, we aim to identify targeted therapy for CS and potentially advance to Phase I human clinical trials. Citation Format: Megan Gorman, Divya Gowthaman, Arielle Katcher, Charlie Chung, Brian Yueh, Mali Barbi, Libia Garcia, Marina Frimer, Gary L. Goldberg, Semir Beyaz. A clinically relevant orthotopic endometrial carcinosarcoma mouse model using human patient-derived organoids [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr B020.

Improving the predictive accuracy of efficacy evaluation using tumor orthotopic transplant and resection model.

Preclinical efficacy evaluation and tumor drug sensitivity analysis are two main applications of efficacy evaluation. Preclinical efficacy evaluation is to predict whether candidate drugs or therapies may improve patient outcomes in clinical trials. Tumor drug sensitivity analysis is an approach for the personalized evaluation and optimization of approved anti-cancer drugs and treatment regimens. Overall survival (OS) is the gold standard to evaluate the outcome of drugs or therapies in both clinical trials and clinical treatment. Many efficacy evaluation models, such as cell model, tumor cell-line transplant model, patient-derived tumor xenograft model, tumor organoid model, have been developed to assess the inhibitory effect of tested drugs or therapies on tumor growth. In fact, many treatments may also lead to malignant progression of tumors, such as chemotherapy, which can lead to metastasis. Therefore, tumor growth inhibition does not necessarily predict OS benefit. Whether it can prevent or inhibit tumor recurrence and metastasis is the key to whether drugs and therapies can improve patient outcomes. In this perspective, we summarize the current understanding of the pathological progression of tumor recurrence and metastasis, point out the shortcomings of existing tumor transplant models for simulating the clinical scenario of malignant progression of tumors, and propose five improved indicators for comprehensive efficacy evaluation to predict OS benefit using tumor orthotopic transplant and resection model. Improvement in the accuracy of efficacy evaluation will accelerate the development process of anti-cancer drugs or therapies, optimize treatment regimens to improve OS benefit, and reduce drug development and cancer treatment costs.

Evaluating the Effects of Kidney Preservation at 10 °C with Hemopure and Sodium Thiosulfate in a Rat Model of Syngeneic Orthotopic Kidney Transplantation.

Kidney transplantation is preferred for end-stage renal disease. The current gold standard for kidney preservation is static cold storage (SCS) at 4 °C. However, SCS contributes to renal graft damage through ischemia-reperfusion injury (IRI). We previously reported renal graft protection after SCS with a hydrogen sulfide donor, sodium thiosulfate (STS), at 4 °C. Therefore, this study aims to investigate whether SCS at 10 °C with STS and Hemopure (blood substitute), will provide similar protection. Using in vitro model of IRI, we subjected rat renal proximal tubular epithelial cells to hypoxia-reoxygenation for 24 h at 10 °C with or without STS and measured cell viability. In vivo, we preserved 36 donor kidneys of Lewis rats for 24 h in a preservation solution at 10 °C supplemented with STS, Hemopure, or both followed by transplantation. Tissue damage and recipient graft function parameters, including serum creatinine, blood urea nitrogen, urine osmolality, and glomerular filtration rate (GFR), were evaluated. STS-treated proximal tubular epithelial cells exhibited enhanced viability at 10 °C compared with untreated control cells (p < 0.05). Also, STS and Hemopure improved renal graft function compared with control grafts (p < 0.05) in the early time period after the transplant, but long-term function did not reach significance. Overall, renal graft preservation at 10 °C with STS and Hemopure supplementation has the potential to enhance graft function and reduce kidney damage, suggesting a novel approach to reducing IRI and post-transplant complications.

Safe Procedure for Efficient Hydrodynamic Gene Transfer to Isolated Porcine Liver in Transplantation.

Although calcineurin inhibitors are very effective as immunosuppressants in organ transplantation, complete graft acceptance remains as a challenge. Transfer of genes with immunosuppressant functions could contribute to improving the clinical evolution of transplantation. In this sense, hydrodynamic injection has proven very efficacious for liver gene transfer. In the present work, the hIL-10 gene was hydrofected 'ex vivo' to pig livers during the bench surgery stage, to circumvent the cardiovascular limitations of the procedure, in a model of porcine orthotopic transplantation with a 10-day follow-up. We used IL-10 because human and porcine proteins can be differentially quantified and for its immunomodulatory pleiotropic functions. Safety (biochemical parameters and histology), expression efficacy (RNA transcription and blood protein expression), and acute inflammatory response (cytokines panel) of the procedure were evaluated. The procedure proved safe as no change in biochemical parameters was observed in treated animals, and human IL-10 was efficaciously expressed, with stationary plasma protein levels over 20 pg/mL during the follow-up. Most studied cytokines showed increments (interferon-α, IFN-α; interleukin-1β, IL-1β; tumor necrosis factor α, TNFα; interleukin-6, IL-6; interleukin-8, IL-8; interleukin-4, IL-4; and transforming growth factor-β, TGF-β) in treated animals, without deleterious effects on tissue. Collectively, the results support the potential clinical interest in this gene therapy model that would require further longer-term dose-response studies to be confirmed.

Abstract B070: Histone deacetylation inhibition promotes bi-directional subtype switch in pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a dismal disease with 5-year survival of just 11%. Recent large-scale transcriptomic studies have identified two prognostically relevant neoplastic tumor subtypes, i.e. the well-differentiated classical (CLA) subtype with better prognosis, characterized by epithelial gene expression, as well as the dedifferentiated, invasive basal-like (BL) subtype, which displays mesenchymal stemness-related gene signatures. These subtypes have shown to be highly plastic and responsive to extrinsic signals, e.g. from the microenvironment or treatment-induced. Here, we investigate master transcription factor networks governing lineage determination in the different subtypes and the role of histone deacetylation (HDAC) co-regulators in their maintenance. We utilized established, subtype-defined PDAC cell lines in vitro and in orthotopic transplantation models to determine subtype plasticity in response to HDAC inhibition by the pan-HDAC inhibitor suberoylanilide hydroxamic acid (SAHA). By integration of RNA-seq, ATAC-seq as well as HiChIP for the activating mark histone 3 lysine 27 acetylation (H3K27ac), we show that the subtype-dependent chromatin organization and regulatory networks can be influenced by pharmacological inhibition of chromatin remodelers, in turn promoting changes in transcription of lineage-determining factors. Targeting these transcription factor networks by HDAC inhibition can lead both to a favorable switch from BL to CLA identity, as well as a detrimental CLA to BL switch. Functional assay such as trans-well invasion further supported the changes in subtype identity following SAHA treatment. This bi-directional subtype switch was additionally validated in patient-derived xenograft cell lines. Together, our findings highlight the importance of understanding the underlying transcriptional and epigenetic mechanisms of the pancreatic cancer subtypes, as they may exhibit opposing responses to targeted therapies. Citation Format: Lukas Klein, Mengyu Tu, Eva K. Schmitt, Frederike Penz, Athanasia Mizi, Stefan Küffer, Elisabeth Hessmann, Argyris Papantonis, Volker Ellenrieder, Shiv K. Singh. Histone deacetylation inhibition promotes bi-directional subtype switch in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B070.