Tumor Implantation Research Articles

TMIC-67. GLIOBLASTOMA AUGMENTS SYSTEMIC IMMUNUNOSUPPRESSION UPON LOSS OF TESTOSTERONE VIA ALTERATION OF GLUCOCORTICOIDS PRODUCTION

Abstract While sex differences in incidence, genetics, and immune changes are established in glioblastoma (GBM), the specific contribution of sex hormones to these differences has not been fully explored. Testosterone has been shown to have a pro-tumorigenic effect on human and mouse GBM tumor cells. However, the systemic effect of testosterone in an immune competent model has not been tested. To test this, we performed castration or sham surgery on C57BL/6 male mice, followed by intracranial implantation of syngeneic glioma cells. Surprisingly, castrated mice exhibited more aggressive tumor growth compared to sham surgery controls, and this castration-induced aggressiveness could be reversed by administering exogenous testosterone. This finding was further confirmed by chemically blocking androgen receptor signaling using enzalutamide. We observed a significant increase in adrenocorticotropic hormone (ACTH) levels in the serum from castrated mice compared to the sham group after tumor implantation. Additionally, mass spectrometry analysis detected elevated levels of circulating glucocorticoids in castrated mice, and pharmacological blockade of glucocorticoid receptor using mifepristone reversed the shorted survival in castrated mice, but not in sham control. Flow analysis revealed decreased production of anti-tumor cytokines such as IFN-γ and TNF-α in CD4+ and CD8+ T cells from tumors and lymph nodes in castrated mice, suggesting systemic immunosuppression in these animals. Indeed, castration of immune-compromised mice, specifically NSG and RAG1KO strains, did not result in reduced survival. Moreover, when GBM cells were subcutaneously implanted into the flank, tumor growth in castrated mice was decelerated compared to sham controls. We also observed significantly lower ACTH levels in the flank tumor model compared to the brain tumor model, indicating a brain-specific effect of steroid hormones on tumor control. Taken together, these findings demonstrate that testosterone regulates T cell function through glucocorticoids, ultimately affecting GBM growth in a site-specific manner.

IMMU-36. PD-1KO HEMATOPOIETIC STEM CELLS RAPIDLY DIFFERENTIATE INTO GLIOMA-INFILTRATING EFFECTOR T-CELLS

Abstract INTRODUCTION We previously published that hematopoietic stem cell combination therapy (HSC+aPD1) extends survival in murine CNS malignancies, including glioma. To better understand lymphoid-specific mechanisms, we analyzed various lymphoid tissues in a murine glioma model. We hypothesize early PD-1 blockade in HSCs influences later differentiation trajectories. Transferred HSCs differentiate into T-cells within the thymus and then migrate to the intracranial tumor microenvironment as anticipated. Indeed, blocking PD-1/PD-L1 signaling during HSC differentiation significantly impacts subsequent T-cell maturation. Remarkably, TILs derived from HSCPD1KO cells were biased towards CD4+ Treg or CD8+ effector lineages, whereas HSCPD1+/+ progeny leaned toward immature/naïve cell states. METHODS HSCs were prepared from constitutive GFP-expressing (CD45.2+) and PD1KO (CD45.2+) mice and transferred into CD45.1+ hosts. Sublethal 5Gy total body irradiation was administered day 5 post-intracranial tumor implantation. The next day, 1e6 HSCs from a 1:1-GFP:PD1KO cocktail were injected intravenously. Descriptive statistics are reported as mean ± SD. Transferred HSCs engraft, expand, differentiate, tended and migrate to form approximately 25% of the TIL compartment in only 15 days. RESULTS We found that, 56.2% ± 20.3 of CD3+ TILs display an immature CD4+CD8+ (DP) phenotype in early disease, and 43.8% ± 17.4 of these DP-TILs are HSC-derived. DP-TILs were virtually absent in advanced disease 29 days after treatment, but HSC-derived TILs most commonly fell within the single-positive (SP) TIL subsets, comprising 9.8% ± 5.6 of SP-CD8+ TILs. Notably, HSCPD1KO-derived cells were 4x more abundant amongst SP-CD8 TILs when compared to HSCGFP-derived cells (6.5% vs 1.6%, p < 0.05). SP-CD8 thymocytes were similarly enriched for HSCPD1KO progeny (41.1% vs 24.7%, p < 0.05) suggesting that PD-1 blockade impacts thymopoiesis directly. CONCLUSION PD-1 signaling modulates thymic output. Blocking the PD-1/PD-L1 axis during thymopoiesis increases the abundance of HSC-derived CD8+ effectors at the tumor site. HSC+aPD1 therapy is uniquely positioned to leverage thymus-dependent anti-tumor immunity.

EXTH-52. LONG-ACTING RECOMBINANT INTERLEUKIN-7, NT-I7, IMPROVES SURVIVAL FOLLOWING ONCOLYTIC ZIKA VIRUS TREATMENT IN THE SB28 IMMUNOSUPPRESSIVE AND TREATMENT-RESISTANT MURINE GLIOMA MODEL

Abstract Glioblastoma (GBM) does not respond to immunotherapy for several reasons, including limited cancer-specific neoantigens and poor T-cell infiltration. The SB28 murine glioma model recapitulates these aspects of human GBM. Zika virus (ZIKV) treatment of GL261 and CT2A-bearing mice resulted in significant survival improvement through multiple mechanisms, including direct tumor killing and induction of a local CD8+ T-cell anti-tumor response, but ZIKV is less effective against SB28 tumors. Previously, we published that a long-acting human IL-7, rhIL-7-hyFc (NT-I7, efineptakin alfa; NeoImmuneTech Inc.), increases T-cell abundance and improves tumor infiltration. Therefore, we hypothesize that combining NT-I7 with oncolytic ZIKV therapy will enhance the anti-tumor response and improve survival in mice bearing SB28 syngeneic tumors. 1×103 SB28 tumor cells were intracranially implanted in C57BL/6J mice. Mice were treated with NT-I7 on post tumor implantation day 7 and 10, followed by intratumoral ZIKV on day 14. Tumor burden was assessed using bioluminescence imaging; mice were monitored for survival and bled weekly to assess the systemic T-cell response to NT-I7. Subcutaneous injection of NT-I7 significantly boosted systemic T-cell abundance compared to control (5,623 cells/uL vs. 136 cells/uL, p < 0.05), particularly cytotoxic CD8+ T-cells (4,776 cells/uL vs. 47 cells/uL, p < 0.05). This increased abundance of CD8+ T-cells peaked at 7 days after initial treatment and persisted for 21 days. NT-I7 monotherapy did not confer any survival benefit. However, the combination of NT-I7 and ZIKV treatment resulted in significant improvement in survival compared to NT-I7 or ZIKV treatment alone (p < 0.05). Treatment with NT-I7 primes the immune system by expanding the circulating CD8+ T-cell population by 100-fold. Timing the oncolytic ZIKV injection with the peak in peripheral CD8+ T-cells greatly improved survival in the immunotherapy resistant SB28 glioma model. These data suggest a role for NT-I7 as an adjunct to various T-cell mediated treatment strategies for GBM.

Platelet Angiopoietin-1 Protects Against Experimental Lung Metastasis By Limiting Tumor Cell Extravasation

In addition to their fundamental roles in hemostasis, platelets can contribute to both tumor growth and metastasis. However, despite being a reservoir for pro-angiogenic and metastatic cytokines, platelets also harbor negative regulators of tumor progression. One such regulator is angiopoietin-1 (Angpt1), an angiogenic cytokine that preserves vascular integrity by promoting cell-cell endothelial interactions downstream of its receptor, the receptor tyrosine kinase Tie-2. In addition, Angpt1 also protects against tumor cell metastasis through an unidentified mechanism. Although platelets are believed to be the primary source of Angpt1 in circulation, the contributions of platelet-derived Angpt1 to tumor growth and metastasis have not been investigated. In this study, we demonstrate that platelet Angpt1 is selectively upregulated in the spontaneous PyMT breast cancer mouse model, but not pre-clinical models of melanoma or non-malignant inflammation (colitis), suggesting a distinct contribution of platelet Angpt1 in breast cancer. To test whether deletion of platelet Angpt1 affects tumor growth or metastasis, we generated mice selectively lacking Angpt1 in megakaryocytes and their platelet progeny (Angpt1 fl/flPF4 Cre, referred to as Angpt1 Plt KO). Plasma Angpt1 was undetectable in Angpt1 Plt KO mice, comparable to mice deficient in the megakaryocyte differentiation factor thrombopoietin, which display approximately 10% of platelet counts. Taken together, these findings establish that platelets are the principal source of circulating Angpt1. In tumor implantation studies, orthotopic tumor growth and vascularization were unaffected in Angpt1 Plt KO mice in pre-clinical models of breast cancer and melanoma. However, Angpt1 Plt KO mice had increased experimental metastasis during both early (3-24 hours) and late (10 days, Figure 1) stages of tumor colonization in both breast cancer and melanoma models, revealing an important role for platelet Angpt1 in restraining the latter stages of tumor metastasis following tumor engraftment. Next, we sought to mechanistically determine how platelet Angpt1 limits tumor cell metastasis. Static adhesion assays demonstrated that platelets lacking Angpt1 did not affect tumor cell attachment to endothelial cells when compared to platelets containing Angpt1. However, Angpt1 Plt KO mice had increased tumor cell retention and extravasation in their lungs following experimental metastasis (3-24 hours), suggesting that platelet Angpt1 limits endothelial permeabilization and the trans-endothelial migration of tumor cells out of blood vessels. Most importantly, all intravascular tumor cells were found within platelet-rich microthrombi immediately after sequestration in the lungs. We therefore conclude that localized Angpt1 released by activated platelets at the site of tumor cell arrest likely reprograms the surrounding endothelium to limit successful tumor cell extravasation. These findings reveal an unexpected role for platelets in restricting tumor cell metastasis.

Pathological features of primary cardiac myxoid tumour in dogs: a review of 11 cases (2002–2022)

This report documents the pathological features of primary cardiac myxoid tumour (MT) in 11 dogs. Macroscopically, all the tumours were located in the tricuspid valve (TV), its septal leaflet being predominantly affected. Therefore, it appears that the TV is the most common site of occurrence for cardiac MT in dogs. Two gross anatomical types of canine valvular MT were evident. Seven of the 11 tumours were round or oval with a smooth or gently lobulated and glistening surface, while the other four were gelatinous, multilobulated and polypoid, with an irregular surface. Microscopically, in nine cases the tumours had an abundant myxoid matrix within which elongated spindle-shaped cells with no remarkable cytological atypia were sparsely embedded, suggesting a benign character (ie, myxoma). In the other two cases the tumours consisted of variably dense, haphazardly arranged, interlacing streams of anaplastic spindle-shaped or polygonal cells containing many mitotic figures, indicative of a malignant form of myxoma (ie, myxosarcoma). Isolated or clustered collections of myxoma cells (eg, cords, rings, syncytia) characteristic of human atrial myxoma were only rarely evident or lacking in all 11 cases, indicating that rarity or absence of such structural features may be specific to valvular MTs. Immunohistochemical findings were indicative of smooth muscle differentiation of the neoplastic cells. Tumour embolization to the intrapulmonary arteries and/or tumour implantation on the endocardium of the right heart chambers was evident only in the four cases of irregular-surfaced MT.

A potential protective role of congenital peritoneal encapsulation coexisting with metastatic colon cancer: a rare case report

Introduction and importance: Congenital peritoneal encapsulation (CPE) is a rare condition in which the small intestine is encased within a mesothelial-lined sac. The following case is an extremely rare description of the co-existence of both colon cancer and peritoneal encapsulation, highlighting the potential role of this co-existence in preventing the spread of metastases and tumor implantation. Case-presentation: A 60-year-old female was diagnosed with metastatic colon cancer. During the operation, a thin fibrous membrane was found covering the small intestine, which suggested CPE. The tumor was removed, and the additional membrane was totally excised. The patient is currently receiving chemotherapy for metastatic treatment and is in good health. Clinical discussion: CPE is a medical condition that results from abnormal peritoneal development, and it is often confused with other differential diagnoses resulting from inflammatory causes. It can occur at different ages and remains asymptomatic for the majority of cases. However, it can be a potential cause of bowel obstruction. An intraoperative diagnosis can easily differentiate the case. The co-existence with colon cancer has been described only once in the literature. Conclusion: Peritoneal encapsulation is a rare, mostly asymptomatic condition. However, it may play a protective role in preventing metastatic colon cancer from affecting the small intestine, thus potentially opening up new avenues for the treatment of cancer metastases.

Surgical experience in cardiac myxomas at a tertiary hospital

IntroductionCardiac myxomas account for 50% of all benign cardiac tumors. Their clinical presentation varies from embolisms to fever. Our objective was to describe the surgical experience in the resection of cardiac myxomas during an 8-year period. MethodsThis is a retrospective, descriptive study of a series of cases with cardiac myxomas diagnosed from 2014 to 2022 at a tertiary care center. Descriptive statistics were used to define the populational and surgical characteristics. We used Pearson’s correlation to study the relationship between postoperative complications and age, tumor size and affected cardiac chamber. Results31 patients were included, with a predominance of females (1:2 ratio). The prevalence was 0.44%, which was calculated based on the number of cardiac surgeries performed in our unit over the 8-year period. The main clinical manifestation was dyspnea (85%, n = 23), followed by cerebrovascular event (CVE) (18%, n = 5). Atriotomy and resection of the pedicle were performed with preservation of the interatrial septum. Mortality was 3.2%. The postoperative evolution was uneventful in 77%. Tumor recurrence occurred in 2 patients (7%), both debuting with embolic phenomena. No association was observed between postoperative complications or recurrence and tumor size, nor aortic clamping and extracorporeal circulation times with regard to age. ConclusionsFour atrial myxoma resections are performed in our unit per year, with an estimated prevalence of 0.44%. The tumor characteristics described coincide with the previous literature. A relationship between embolisms and recurrences cannot be ruled out. Wide surgical resection of the pedicle and base of tumor implantation may influence tumor recurrence, although further studies are needed.

Proteomics, Transcriptomics, and Phosphoproteomics Reveal the Mechanism of Talaroconvolutin-A Suppressing Bladder Cancer via Blocking Cell Cycle and Triggering Ferroptosis

Talaroconvolutin-A (TalaA) is a compound from the endophytic fungus T. convolutispora of the Chinese herbal medicine Panax notoginseng. Whether TalaA exerts anticancer activity in bladder cancer remains unknown. Using CCK8 assay, EdU staining, crystal violet staining, flow cytometry, living/dead cell staining, and Western blotting, we studied the anticancer activity of TalaA in vitro. Moreover, we performed xenograft tumor implantation. The antitumor effects were evaluated through H&E and immunohistochemistry staining. Proteomics was conducted to detect changes in the protein profile; transcriptomics was performed to detect changes in mRNA abundance; phosphoproteomics was used to detect changes in protein phosphorylation. TalaA inhibited tumor cell proliferation, DNA replication, and colony formation in a dose-dependent manner in bladder cancer cells. The IC50 values of TalaA on SW780 and UM-UC-3 cells were 5.7 and 8.2 μM, respectively. TalaA (6.0 mg/kg) significantly repressed the growth of xenografted tumors and did not affect the body weight nor cause obvious hepatorenal toxicity. TalaA arrested the cell cycle by downregulating cyclinA2, cyclinB1, and AURKB and upregulating p21/CIP. TalaA also elevated intracellular reactive oxygen species and upregulated transferrin and heme oxygenase 1 to induce ferroptosis. Moreover, TalaA was able to bind to MAPKs (MAPK1, MAPK8, and MAPK14) to inhibit the phosphorylation of ∗SP∗ motif of transcription regulators. This study revealed that TalaA inhibited bladder cancer by arresting cell cycle to suppress proliferation and triggering ferroptosis to cause cell death. Conclusively, TalaA would be a potential candidate for treating bladder cancer by targeting MAPKs, suppressing the cell cycle, and inducing ferroptosis.

Enhancing Immune-Mediated Radiotherapy Efficacy in Murine Models of Head and Neck Cancer through Peroxisome Proliferator-Activated Receptor Modulation

The tumor microenvironment (TME) in HPV-unrelated head and neck cancer (HNC) is considered to be immunologically "cold," and immunometabolic adaptations to radiotherapy (RT) can exacerbate these conditions and lead to radioresistance. Peroxisome proliferator-activated receptor-α (PPARα) agonism may improve the immune response to RT by reducing glucose scarcity through upregulation of fatty acid utilization in cancer cells. Our clinical trial data shows that high serum oleic acid (OA), a PPAR ligand, correlates with response to radioimmunotherapy. Orthotopic buccal tumor implantations of MOC2 and LY2 HNC cell lines were performed in C57BL/6 and BALB/c mice, respectively. Mice were placed on a high OA diet (38% kcal from OA) 3 weeks prior to tumor implantation. Control diet consisted of 1% kcal from OA. In vitro RT was performed to characterize the metabolic effects on the cancer cell lines. For in vivo studies, tumors were irradiated upon reaching 100 mm^3 with three 8 Gy fractions, given every 4-5 days. The PPARα agonist fenofibrate (FF, 100mg/kg/day) was given via oral gavage or intraperitoneal injection starting 5 days after RT. Tumor volume and overall survival were measured as objective outcomes, and flow cytometry was used to characterize the immune landscape of the tumor, blood, and lymph nodes. Mass spectrometry was employed for bulk proteomics and metabolomics on serum samples, and stable isotope labeling was performed on CD8 T cells from treated mice ex vivo. Extracellular flux analyses were performed on tumor cells and CD8 T cells to determine metabolic phenotypic changes. In vitro cytotoxicity was met for MOC2 and LY2 cancer cells in 100 uM FF and OA in comparison to solvent (p<0.01). Extracellular flux analyses show that RT upregulates the glycolytic phenotype of MOC2 and LY2 cancer cells; and that FF and/or OA decrease the glycolytic capacity of the cancer cells. Ex vivo extracellular flux analyses showed increased glycolytic capacity of CD8 T cells in mice treated with FF in comparison to RT alone. RT in combination with FF significantly improved tumor volume response in comparison to RT alone (mean 99.4 vs 182.7 mm^3, p = 0.001) and was comparable to combination radioimmunotherapy (with anti-PDL1 therapy; mean 99.4 vs. 132.3 mm^3). Unexpectedly, OA negated this improvement in efficacy in both MOC2 and LY2 tumor models; mice on the high OA diet had significantly higher average body weight (p<0.01). Significant changes in adaptive immune response were observed within the TME with the addition of FF. This was mirrored by changes in serum metabolomics. PPARα agonism improved the efficacy of RT in murine HNC models and could be considered in future translational clinical trial design.

Abstract PO-088: TRPV1+ sensory neurons provide a tumor supportive environment through recruitment of MDSCs

Abstract Cancer neuroscience has become an increasing area of focus in cancer research as our understanding of the presence and function of intra-tumoral neurons continues to emerge, with studies indicating that tumor infiltrating neurons impact components of the tumor microenvironment promoting cancer initiation and progression. We have previously published that head and neck squamous cell carcinomas are innervated. We now focus on defining the contributions of intra-tumoral neurons to disease progression in HNSCC. Tumor implantation in a double transgenic mouse (TRPV1cre::DTAfl/wt) lacking the cancer-recruited TRPV1-expressing sensory neurons allows us to study the consequences of this neuronal loss on the local immune response. Importantly, comparison between wild type and TRPV1cre::DTAfl/wt mice demonstrated no significant immune population differences at baseline. Thus, wildtype and TRPV1cre::DTAfl/wt mice were orthotopically implanted with tumor and tumoral immune cell populations identified by flow cytometry. Cytokine and peptide concentrations were measured by ELISA. In vitro assays were preformed to molecularly define the neuronal signals and immune responses. Here, co-culture experiments of immortalized head and neck cancer cell lines and dorsal root ganglia (DRG) from wildtype mice were used to model tumor innervation in vitro. The media generated was applied to bone marrow derived (BMD) immune cells and the impact on immune cell phenotypes assayed by flow cytometry. Our orthotopic model demonstrates that the presence of HNSCC promotes a nerve-injury phenotype in ipsilateral trigeminal ganglion, demonstrated by increased expression of activating transcription factor 3 (ATF3). Utilizing a 12-color flow cytometry panel we show that tumors from TRPV1cre::DTAfl/wt mice harbor a significantly smaller population of myeloid derived suppressor cells (MDSCs) compared to those from wildtype animals. Further analysis demonstrates this population shift occurs primarily due to a decrease in the CD11b+ Ly6G+/Ly6Clo population. In vitro studies using BMD immune cells show that tumor cell-DRG co-culture conditioned media induces an expansion of the MDSC population compared to condition media from DRG or tumor cells alone. Additionally, transwell migration assays show that co-culture condition media also increases cellular migration compared to condition media from DRG or tumor cells alone. Moreover, ELISA analysis indicates that co-culture of tumor cells and DRG increases neuronal release of the neuropeptide, Substance P (SP), potentiating IL-6 release from tumor cells. In summary, we identified several mechanisms by which TRPV1-expressing intra-tumoral neurons promote MDSC infiltration at the tumor bed and promote disease progression. These mechanisms define targets for therapeutic intervention including SP and IL-6 signaling. Future studies will test the clinical utility of these targets. Together, our data suggests that intra-tumoral neurons contribute to cancer progression through generation of a tumor supportive microenvironment. Citation Format: Anthony C. Restaino, Maryam Ahmadi, Sebastien Talbot, Paola D. Vermeer. TRPV1+ sensory neurons provide a tumor supportive environment through recruitment of MDSCs [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Innovating through Basic, Clinical, and Translational Research; 2023 Jul 7-8; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2023;29(18_Suppl):Abstract nr PO-088.

In vivo deuterium magnetic resonance imaging of xenografted tumors following systemic administration of deuterated water

In vivo deuterated water (2H2O) labeling leads to deuterium (2H) incorporation into biomolecules of proliferating cells and provides the basis for its use in cell kinetics research. We hypothesized that rapidly proliferating cancer cells would become preferentially labeled with 2H and, therefore, could be visualized by deuterium magnetic resonance imaging (dMRI) following a brief period of in vivo systemic 2H2O administration. We initiated systemic 2H2O administration in two xenograft mouse models harboring either human colorectal, HT-29, or pancreatic, MiaPaCa-2, tumors and 2H2O level of ~ 8% in total body water (TBW). Three schemas of 2H2O administration were tested: (1) starting at tumor seeding and continuing for 7 days of in vivo growth with imaging on day 7, (2) starting at tumor seeding and continuing for 14 days of in vivo growth with imaging on day 14, and (3) initiation of labeling following a week of in vivo tumor growth and continuing until imaging was performed on day 14. Deuterium chemical shift imaging of the tumor bearing limb and contralateral control was performed on either day 7 of 14 after tumor seeding, as described. After 14 days of in vivo tumor growth and 7 days of systemic labeling with 2H2O, a clear deuterium contrast was demonstrated between the xenografts and normal tissue. Labeling in the second week after tumor implantation afforded the highest contrast between neoplastic and healthy tissue in both models. Systemic labeling with 2H2O can be used to create imaging contrast between tumor and healthy issue, providing a non-radioactive method for in vivo cancer imaging.

Efficacy and Safety of MRI and CT Guided VX2 Hepatic Para-vascular Tumor Model in Rabbits.

To compare the efficacy and safety of 1.5 T MRI and CT-guided VX2 hepatic para-vascular tumor model in rabbits. Sixty New Zealand white rabbits were randomly and equally divided into MRI-guided group (n=30) and CT-guided group (n=30). Rabbit VX2 tumor fragments were implanted beside the rabbit hepatic great vessels under MRI and CT guidance in the MRI and CT group to evaluate the success rate of tumor model establishment, puncture needle display and tip peripheral vascular situation, operation time and safety. In the MRI-guided group, 29 rabbits (29/30, 96.7%) had a successful establishment of liver tumor model, and 1 rabbit had needle metastasis. In the CT-guided group, 24 rabbits (24/30, 80%) had a successful establishment of liver tumor model, while 2 rabbits had needle metastasis, 3 rabbits had metastases in other parts of the liver, and 1 had an unknown cause of death. The differences in tumor model establishment success rate between the two groups were statistically significant (χ2 = 4.043, P < 0.05). The fold number of artifacts at T1WI was 7.26±0.38 for the 20 G coaxial puncture needle in the MRI-guided group and 2.51±0.57 for the 20 G coaxial puncture needle in the CT-guided group, and the difference was statistically significant (t=36.76, P < 0.001), but star-shaped hypodense artifacts would appear around the needle tip. The operation time was longer in the MRI-guided group than in the CT-guided group (13.32±2.45 minutes in the MRI-guided group vs. 8.42±1.46 minutes in the CTguided group; t=9.252, P < 0.001). A small number of ascites occurred in 2 patients (2/30, 6.67%) in the CT-guided group; no serious complications such as liver abscess, jaundice or diaphragmatic perforation were observed in both groups. Compared with CT, MRI-guided hepatic para-vascular tumor implantation in rabbits might be a more effective modeling method. Although the needle tip pseudopacity of the puncture needle is large and the operation time is long, the incidence of complications is low.

SP10.8 An overlooked step in colorectal cancer anastomosis: a potentially small step in prevention of exfoliated malignant cells

Abstract Introduction Recurrence after potentially curative surgery has a significant clinical impact with a related poor prognosis. There is an abundance of literature surrounding efficacious techniques for anastomosis. However, to our knowledge comparatively there is minimal evidence reviewing the use of simple anti-septic agents with concurrent cytotoxic properties (ie. betadine or cetrimide) in prevention of anastomotic recurrence. This is despite both historic and newer evidence demonstrating tumour implantation of exfoliated malignant cells (EMCs) at the site of anastomosis leading to recurrence. This is also evident in low grade cancers. Methods A literature search was conducted between January 1980 to January 2022. The studies were to incorporate the use of simple anti-septic agents that were swabbed on the ends of the bowel before anastomosis. The search was restricted to articles published in English. Further more the selected publications were searched for additional studies. Results A result of 243 papers were reviewed, observational studies were found, n- 24. The reported reduction in EMCs was significantly lower at only 2 -7% compared to 16 to 55% in the control groups. Also evidenced were multiple papers providing significant experimental evidence of EMCs on staplers, gloves and the bowel anastomosed. We excluded rectal irrigation from this review article, as it is not employing the method of delivery suitable for all colonic anastomoses. Conclusion These results supporting the theory that cleansing with a cytocidal agent is associated with significantly reduced incidence of local luminal recurrence. We propose that this overlooked step in anastomotic techniques should be revisited.

A pilot in vivo study: potential ovarian cancer therapeutic by placental extracellular vesicles.

The biological links between cancer and pregnancy are of interest due to parallel proliferative, immunosuppressive, and invasive mechanisms between tumour and placental cells. However, the proliferation and invasion of placental cells are strictly regulated. The understanding of this regulation is largely unknown. Placental extracellular vesicles (EVs) may play an important role in this regulation, as placental EVs are known to contribute to maternal adaptation, including adaptation of the vascular and immune systems. We have previously reported that placental EVs significantly inhibited ovarian cancer cell proliferation by delaying the progression of the cell cycle. We therefore performed this pilot in vivo study to investigate whether placental EVs can also inhibit ovarian tumour growth in a SKOV-3 human tumour xenograft model. A single intraperitoneal injection of placental EVs at 15 days post tumour implantation, significantly inhibited the growth of the tumours in our in vivo model. Signs of cellular necrosis were observed in the ovarian tumour tissues, but not in other organs collected from mice that had been treated with placental EVs. Expression of receptor-interacting kinase 1 (RIPK1) and mixed linkage kinase domain-like (MLKL), which are mediators of necroptosis were not observed in our xenografted tumors. However, extensive infiltration of CD169+ macrophages and NK cells in ovarian tumour tissues collected from placental micro-EVs treated mice were observed. We demonstrate here that inhibition of ovarian tumour growth in our xenograft model by placental EVs involves cellular necrosis and infiltration of CD169+ macrophages and NK cells into the tumour tissues.

RETRACTED ARTICLE: Green synthesis of oncolytic Newcastle disease virus-loaded thiolated chitosan nanoformulation for CD44 targeted delivery and sustained release of virus in cervical cancer xenografts

BackgroundNewcastle disease virus (NDV) Lasota strain has proven oncolytic activity. One shortcoming associated with this treatment modality is the immune neutralization of the virus in body, mediated by natural killer cells and macrophages. This study aims at encapsulating the oncolytic virus in thiolated chitosan nanoparticles, surface functionalized with hyaluronic acid for CD44 targeted delivery and sustained release of NDV in cervical cancer tumors. These nanoparticles were tested for oncolytic potential in HeLa cells and cervical cancer xenograft model.ResultsNDV-loaded nanoparticles were prepared using TCs concentration of 1.0 mg/mL, HA at 0.5 mg/mL, with a half dose (not less than 500 TCID units) of NDV by using green synthesis approach through ionic gelation method. Viral quantification in nanoparticles was done by TCID50 (50% tissue culture infectious dose) and MOI (multiplicity of infection) determination. Ex vivo NK cell activity was analyzed by quantifying levels of IFN-γ. In vivo analysis was performed on wistar rats, immunocompromised by using ketoconazole (10 mg/kg) and cyclosporin (30 mg/kg) along with 0.1 μg/mL of amoxicillin. WBC profiling on day 7 confirmed immunosuppression, which was followed by tumor implantation. Zeta analysis of NDV nanoparticles showed that nanoparticles are 286.9 nm in size with a zeta potential of 18.1 mV and PDI of 0.241. For estimation of anticancer potential, MTT and trypan blue exclusion assay revealed a higher cytotoxic potential of the encapsulated virus, while TCID50 of HA-TC-NDV was 4.1 as compared to naked NDV virus which had TCID50 of 6.0 on HeLa cells. Histopathology of organs from NDV nanoparticle-treated rats showed syncytia formation in tumors, immunohistochemical analysis showed decrease in expression of TNF-α, COX-II and NF-ƙB which was also confirmed by ELISA. RT-PCR showed high viral copy number in tumor tissue and viral accumulation in lungs and liver. Lower IFN-γ in nanoparticles treated rats showed suppression in immunoreactivity of virus-loaded nanoparticles.ConclusionOur findings suggest that encapsulation of the virus in thiolated chitosan and CD44 targeting enhanced retention and sustained release of the virus in tumors as compared to pure NDV, with increased oncolytic effect both in vitro and in vivo.

Curbing Exosome Communications via Introducing Artificial Membrane Receptors for Metastatic Pancreatic Cancer Therapy.

Tumor-derived exosomes (TDEs) carry various biomolecular cargos and play crucial roles in metastasis. TDEs migrate to distal organs for intercellular communication and induce the formation of pre-metastatic niches (PMNs) to support tumor implantation and proliferation. Precise interference in the bioprocess of TDEs is expected to be efficacious for suppressing tumor metastasis. However, targeting both TDEs and the primary tumor is challenging. Here, based on metabolic glycoengineering and bio-orthogonal click chemistry, a two-step delivery strategy is designed to overcome this. During the first step, the tetraacetylatedN-azidoacetyl-d-mannosamine-loaded nanoparticle responds to the metabolic activity of tumor cells in the primary tumor, tagging both tumor cells and TDEs with azide groups; dibenzyl-cyclootyne-modified nanoparticles then can, as the second step, specifically react with tumor cells and TDEs through a bio-orthogonal click reaction. This strategy not only inhibits tumor growth in pancreatic cancer models but also curbs the communicative role of TDEs in inducing liver PMNs and metastasis by tracking and downregulating the exosomal macrophage migration inhibitory factor.

Biomaterial considerations for ovarian cancer models

Ovarian cancer is the 5th most common and the deadliest gynecological cancer, with a 5-year survival rate of less than 50 percent. Most deaths due to ovarian cancer are caused by recurrent disease, which typically corresponds to an increase in chemoresistance of the tumor cells. However, little is known about how ovarian tumor chemoresponse changes and if such changes are regulated by the tumor microenvironment (TME). Moreover, the ovarian TME, including the tissue compositions and biomechanical features, is not well-characterized primarily due to a lack of optimal models. To more effectively characterize the TME of ovarian cancer, which may help develop innovative treatment strategies, appropriate models are desperately needed. The most utilized models include mouse models with both patient-derived xenografts and mouse or human tumor cell line derivatives, and more recently microphysiological systems (MPS). While mouse models provide high levels of physiological complexity, there is virtually no control over the TME components after tumor initiation or implantation. On the other hand, MPS or organoid models permit high levels of control of initial composition but lack many features of in vivo models. Selection of appropriate components to create a TME model is paramount for generating a physiologically relevant in vitro and ex vivo systems. The importance of biomaterial or matrix selection in ovarian TME models lies in the role of these components to activate oncogenic signaling pathways either through receptor-ligand interactions or mechanotransduction. Recent studies suggest that off-target or post-target effects of chemotherapies may interfere with mechanotransductive pathways. In ovarian cancer, changes in fibrous proteins, adhesive glycoproteins, and glycosaminoglycans can remodel the mechanical environment, further altering mechanotransductive pathways. Therefore, the next-generation of ovarian tumor models should incorporate relevant biomaterials including hyaluronic acid (HA), collagens, fibrinogen, and fibronectin to investigate the link between matrix properties and mechanobiology with metastasis and chemoresistance.

Reactivation of low avidity tumor-specific CD8+ T cells associates with immunotherapeutic efficacy of anti-PD-1

BackgroundCD8+ T cells are a highly diverse population of cells with distinct phenotypic functions that can influence immunotherapy outcomes. Further insights on the roles of CD8+ specificities and TCR avidity...

Exercise improves the outcome of anticancer treatment with ultrasound-hyperthermia-enhanced nanochemotherapy and autophagy inhibitor.

It has been shown that exercise has a direct impact on tumor growth along with functional improvement. Previous studies have shown that exercise decreases the risk of cancer recurrence across various types of cancer. It was indicated that exercise stimulates the immune system to fight cancer. Previous study demonstrated that pulsed-wave ultrasound hyperthermia (pUH) combined with PEGylated liposomal doxorubicin (PLD) and chloroquine (CQ) inhibits 4T1 tumors growth and delays their recurrence. In this study, we investigated if the combinatorial treatment with high-intensity interval training (HIIT) combined with pUH-enhanced PLD delivery and CQ improved the outcome. The mouse experiment composed of three groups, HIIT+PLD+pUH+CQ group, PLD+pUH+CQ group, and the control group. HIIT+PLD+pUH+CQ group received 6 weeks of HIIT (15 min per day, 5 days per week) before 4T1 tumor implantation. Seven days later, they received therapy with PLD (10 mg/kg) + pUH (3 MHz, 50% duty cycle, 0.65 W/cm2, 15min) + CQ (50 mg/kg daily). Results showed that HIIT+PLD+pUH+CQ significantly reduced the tumor volumes and brought about longer survival of tumor-bearing mice than PLD+pUH+CQ did. Blood cell components were analyzed and showed that neutrophil and reticulocytes decreased while lymphocytes increased after exercise.

Surgical experience in cardiac myxomas at a tertiary hospital

IntroductionCardiac myxomas account for 50% of all benign cardiac tumors. Their clinical presentation varies from embolisms to fever. Our objective was to describe the surgical experience in the resection of cardiac myxomas during an 8-year period. MethodsThis is a retrospective, descriptive study of a series of cases with cardiac myxomas diagnosed from 2014 to 2022 at a tertiary care center. Descriptive statistics were used to define the populational and surgical characteristics. We used Pearson’s correlation to study the relationship between postoperative complications and age, tumor size and affected cardiac chamber. Results31 patients were included, with a predominance of females (1:2 ratio). The prevalence was 0.44%, which was calculated based on the number of cardiac surgeries performed in our unit over the 8-year period. The main clinical manifestation was dyspnea (85%, n = 23), followed by cerebrovascular event (CVE) (18%, n = 5). Atriotomy and resection of the pedicle were performed with preservation of the interatrial septum. Mortality was 3.2%. The postoperative evolution was uneventful in 77%. Tumor recurrence occurred in 2 patients (7%), both debuting with embolic phenomena. No association was observed between postoperative complications or recurrence and tumor size, nor aortic clamping and extracorporeal circulation times with regard to age. ConclusionsFour atrial myxoma resections are performed in our unit per year, with an estimated prevalence of 0.44%. The tumor characteristics described coincide with the previous literature. A relationship between embolisms and recurrences cannot be ruled out. Wide surgical resection of the pedicle and base of tumor implantation may influence tumor recurrence, although further studies are needed.