Mouse Model Of Peritoneal Metastasis Research Articles

Hydroxygenkwanin suppresses peritoneal metastasis in colorectal cancer by modulating tumor-associated macrophages polarization

Peritoneal metastasis is an important cause of high mortality and poor prognosis in colorectal cancer (CRC) patients. Therefore, the development of compounds with unique anti-CRC Peritoneal metastasis activities is urgently needed to improve the survival of CRC patients. Hydroxygenkwanin (HGK),a natural flavonoid compound, have been shown to display anti-inflammatory, antioxidant, antitumor, and immunoregulatory effects. Here, we employed CRC peritoneal metastasis mouse model with MC38 cells to examine the antitumor activity of HGK. The result showed that HGK not only inhibited peritoneal metastasis, but also significantly increased the proportion of M1-like macrophages while decreasing the proportion of M2-like macrophages within the tumor microenvironment (TME). Furthermore, we demonstrated that the inhibitory effect of HGK on peritoneal metastasis of CRC depended on macrophages in vitro and in vivo. Moreover, we revealed that HGK promoted the polarization of TAMs into M1-like macrophages and inhibited their polarization into M2-like macrophages in a LPS- or IL-4-induced bone marrow-derived macrophages (BMDMs) model and co-culture system. Finally, we also investigated the regulatory mechanism of HGK on TAMs polarization that HGK may active p-STAT5, p–NF–κB signaling in M1-like macrophages and inhibit p-STAT6, JMJD3, PPARγ expression in M2-like macrophages. Taken together, our findings suggest that HGK is a natural candidate for effective prevention of peritoneal metastasis in colorectal cancer, which provides a potential strategy for clinical treatment of colorectal cancer.

Low-dose radiotherapy synergizes with iRGD-antiCD3-modified T cells by facilitating T cell infiltration

Background and purposePoor penetration of transferred T cells represents a critical factor impeding the development of adoptive cell therapy in solid tumors. We demonstrated that iRGD-antiCD3 modification promoted both T cell infiltration and activation in our previous work. Interest in low-dose radiotherapy has recently been renewed due to its immuno-stimulatory effects including T cell recruitment. This study aims to explore the synergistic effects between low-dose radiotherapy and iRGD-antiCD3-modified T cells. Materials and methodsFlow cytometry was performed to assess the expression of iRGD receptors and chemokines. T cell infiltration was evaluated by immunohistofluorescence and in vivo real-time fluorescence imaging and antitumor effects were investigated by in vivo bioluminescence imaging in the gastric cancer peritoneal metastasis mouse model. ResultsWe found that 2 Gy irradiation upregulated the expression of all three iRGD receptors and T-cell chemokines. The addition of 2 Gy low-dose irradiation boosted the accumulation and penetration of iRGD-antiCD3-modified T cells in peritoneal tumor nodules. Combining 2 Gy low-dose irradiation with iRGD-antiCD3-modified T cells significantly inhibited tumor growth and prolonged survival in the peritoneal metastasis mouse model with a favorable safety profile. ConclusionAltogether, we demonstrated that low-dose radiotherapy could improve the antitumor potency of iRGD-antiCD3-modified T cells by promoting T cell infiltration, providing a rationale for exploring low-dose radiotherapy in combination of other adoptive T cell therapies in solid tumors.

Investigation of the effectiveness of hyperthermic intraperitoneal chemotherapy in experimental colorectal peritoneal metastasis model.

In our study, we aimed to (1) create a peritoneal metastasis (PM) model in nude mice, administer intraperitoneal chemotherapy using the peritoneal infusion pump we developed in this model, and (2) compare the efficacy of intraperitoneal chemotherapy using various drugs at different temperatures. The peritoneal metastasis model was established in nude mice using the CC531 colon carcinoma cell line. Models with peritoneal metastasis (PM) were randomized into four groups of seven animals each: Group 1, control group (n=7); Group 2, normothermic intraperitoneal chemotherapy (NIPEC) with mitomycin C(MMC) (n=7); Group 3, hyperthermic intraperitoneal chemotherapy (HIPEC) with mitomycin C (n=7), and Group 4, NIPEC with 5-fluorouracil (5-FU). Tumor development was achieved in all animals. While the tumor burden decreased significantly in the treatment Group 3 (p=0.034), no significant difference was found in the other groups. In the PM mouse model, hyperthermic intraperitoneal administration of MMC had the highest tumoricidal effect. Our PM model provided a good opportunity to examine the efficacy of HIPEC and intraperitoneal infusion pump (IPIP). In future studies, we plan to evaluate efficacies of different drugs in the PM models we have created.

G-CSF Is a Novel Mediator of T-Cell Suppression and an Immunotherapeutic Target for Women with Colon Cancer.

G-CSF enhances colon cancer development. This study defines the prevalence and effects of increased G-CSF signaling in human colon cancers and investigates G-CSF inhibition as an immunotherapeutic strategy against metastatic colon cancer. Patient samples were used to evaluate G-CSF and G-CSF receptor (G-CSFR) levels by IHC with sera used to measure G-CSF levels. Peripheral blood mononuclear cells were used to assess the rate of G-CSFR+ T cells and IFNγ responses to chronic ex vivo G-CSF. An immunocompetent mouse model of peritoneal metastasis (MC38 cells in C57Bl/6J) was used to determine the effects of G-CSF inhibition (αG-CSF) on survival and the tumor microenvironment (TME) with flow and mass cytometry. In human colon cancer samples, the levels of G-CSF and G-CSFR are higher compared to normal colon tissues from the same patient. High patient serum G-CSF is associated with increases in markers of poor prognosis, (e.g., VEGF, IL6). Circulating T cells from patients express G-CSFR at double the rate of T cells from controls. Prolonged G-CSF exposure decreases T cell IFNγ production. Treatment with αG-CSF shifts both the adaptive and innate compartments of the TME and increases survival (HR, 0.46; P = 0.0237) and tumor T-cell infiltration, activity, and IFNγ response with greater effects in female mice. There is a negative correlation between serum G-CSF levels and tumor-infiltrating T cells in patient samples from women. These findings support G-CSF as an immunotherapeutic target against colon cancer with greater potential benefit in women.

A disintegrin and metalloprotease 12 contributes to colorectal cancer metastasis by regulating epithelial‑mesenchymal transition.

A disintegrin and metalloprotease 12 (ADAM12) and epithelial‑mesenchymal transition (EMT) are linked in the metastasis of various types of cancer. The present study aimed to assess the ability of ADAM12 to induce EMT and its potential as a therapeutic target for colorectal cancer (CRC). ADAM12 expression in CRC cell lines, CRC tissues and a mouse model of peritoneal metastasis was assessed. The effect of ADAM12 on CRC EMT and metastasis was investigated using ADAM12‑pcDNA6‑myc and ADAM12‑pGFP‑C‑shLenti constructs. ADAM12 overexpression enhanced the proliferation, migration, invasion and EMT of CRC cells. The phosphorylation levels of factors associated with the PI3K/Akt pathway were also increased by ADAM12 overexpression. The knockdown of ADAM12 reversed these effects. ADAM12 expression and the loss of E‑cadherin expression were significantly associated with poorer survival compared with other expression statuses of both proteins. In a mouse model of peritoneal metastasis, overexpression of ADAM12 induced increased tumor weight and peritoneal carcinomatosis index compared with that in the negative control group. Conversely, knockdown of ADAM12 reversed these effects. Furthermore, E‑cadherin expression was significantly decreased by overexpression of ADAM12 compared with in the negative control group. By contrast, E‑cadherin expression was increased by knockdown of ADAM12 compared with in the negative control group. ADAM12 overexpression contributed to CRC metastasis by regulating EMT. In addition, in the mouse model of peritoneal metastasis, ADAM12 knockdown exhibited strong anti‑metastatic action. Consequently, ADAM12 may be considered a therapeutic target for CRC metastasis.

Hypoxia-Induced CD36 Expression in Gastric Cancer Cells Promotes Peritoneal Metastasis via Fatty Acid Uptake

BackgroundThe lipid scavenger receptor cluster of differentiation 36 (CD36) has been shown to have a pro-metastatic function in several cancers. Adipose tissue, a favorable site for peritoneal metastasis (PM) from gastric cancer (GC), promotes this process by providing free fatty acids (FFAs); however, the role of CD36 in PM progression from GC remains to be elucidated.Materials and MethodsWe evaluated CD36 expression in the GC cells under various conditions. CD36 overexpressing (CD36OE) MKN45 cells were prepared and their migration and invasive properties were assessed. A PM mouse model was used to investigate the biological effects of palmitic acid (PA) and CD36. Furthermore, we examined the clinical role of CD36 expression in 82 human PM samples by immunohistochemical staining.ResultsHypoxia markedly increased CD36 expression in GC cells. In normoxia, only CD36OE MKN45 cells treated with PA showed an increase in migration and invasion abilities. An increased expression of active Rac1 and Cdc42 was observed, which decreased following etomoxir treatment. Conversely, hypoxia increased those capacities of both vector and CD36OE MKN45 cells. In a mouse model transplanted with CD36OE MKN45 cells, more peritoneal tumors were observed in the high-fat diet group than those in the normal diet group. In clinical samples, 80% of PM lesions expressed CD36, consistent with hypoxic regions, indicating a significant association with prognosis.ConclusionOur findings indicate that a hypoxia in the peritoneal cavity induces CD36 expression in GC cells, which contributes to PM through the uptake of FFAs.

Heart Rate Variability as a Potential Indicator of Cancer Pain in a Mouse Model of Peritoneal Metastasis.

Heart rate variability (HRV) is closely related to changes in the autonomic nervous system (ANS) associated with stress and pain. In this study, we investigated whether HRV could be used to assess cancer pain in mice with peritoneal metastases. At 12 days after cancer induction, positive indicators of pain such as physiological characteristics, appearance, posture, and activity were observed, and time- and frequency-domain HRV parameters such as mean R-R interval, square root of the mean squared differences of successive R-R intervals, and percentage of successive R-R interval differences greater than 5 ms, low frequency (LF), high frequency (HF), and ratio of LF and HF power, were found to be significantly decreased. These parameters returned to normal after analgesic administration. Our results indicate that overall ANS activity was decreased by cancer pain and that HRV could be a useful tool for assessing pain.

SCD1/FADS2 fatty acid desaturases equipoise lipid metabolic activity and redox-driven ferroptosis in ascites-derived ovarian cancer cells.

Rationale: Malignant ascites in peritoneal metastases is a lipid-enriched microenvironment and is frequently involved in the poor prognosis of epithelial ovarian cancer (EOC). However, the detailed mechanisms underlying ovarian cancer (OvCa) cells dictating their lipid metabolic activities in promoting tumor progression remain elusive.Methods: The omental conditioned medium (OCM) was established to imitate the omental or ascites microenvironment. Mass spectrometry, RT-qPCR, IHC, and western blot assays were applied to evaluate human fatty acid desaturases expressions and activities. Pharmaceutical inhibition and genetic ablation of SCD1/FADS2 were performed to observe the oncogenic capacities. RNA sequencing, lipid peroxidation, cellular iron, ROS, and Mito-Stress assays were applied to examine ferroptosis. OvCa patient-derived organoid and mouse model of peritoneal metastases were used to evaluate the combined effect of SCD1/FADS2 inhibitors with cisplatin.Results: We found that two critical fatty acid desaturases, stearoyl-CoA desaturase-1 (SCD1) and acyl-CoA 6-desaturase (FADS2), were aberrantly upregulated, accelerating lipid metabolic activities and tumor aggressiveness of ascites-derived OvCa cells. Lipidomic analysis revealed that the elevation of unsaturated fatty acids (UFAs) was positively associated with SCD1/FADS2 levels and the oncogenic capacities of OvCa cells. In contrast, pharmaceutical inhibition and genetic ablation of SCD1/FADS2 retarded tumor growth, cancer stem cell (CSC) formation and reduced platinum resistance. Inhibition of SCD1/FADS2 directly downregulated GPX4 and the GSH/GSSG ratio, causing disruption of the cellular/mitochondrial redox balance and subsequently, iron-mediated lipid peroxidation and mitochondrial dysfunction in ascites-derived OvCa cells.Conclusions: Combinational treatment with SCD1/FADS2 inhibitors and cisplatin synergistically repressed tumor cell dissemination, providing a promising chemotherapeutic strategy against EOC peritoneal metastases.

10ns PEFs induce a histological response linked to cell death and cytotoxic T-lymphocytes in an immunocompetent mouse model of peritoneal metastasis.

The application of nanosecond pulsed electric fields (nsPEFs) could be an effective therapeutic strategy for peritoneal metastasis (PM) from colorectal cancer (CRC). The aim of this study was to evaluate in vitro the sensitivity of CT-26 CRC cells to nsPEFs in combination with chemotherapeutic agents, and to observe the subsequent in vivo histologic response. In vitro cellular assays were performed to assess the effects of exposure to 1, 10, 100, 500 and 1000 10 ns pulses in a cuvette or bi-electrode system at 10 and 200 Hz. nsPEF treatment was applied alone or in combination with oxaliplatin and mitomycin. Cell death was detected by flow cytometry, and permeabilization and intracellular calcium levels by fluorescent confocal microscopy after treatment. A mouse model of PM was used to investigate the effects of in vivo exposure to pulses delivered using a bi-electrode system; morphological changes in mitochondria were assessed by electron microscopy. Fibrosis was measured by multiphoton microscopy, while the histological response (HR; hematoxylin-eosin-safran stain), proliferation (KI67, DAPI), and expression of immunological factors (CD3, CD4, CD8) were evaluated by classic histology. 10 ns PEFs exerted a dose-dependent effect on CT-26 cells in vitro and in vivo, by inducing cell death and altering mitochondrial morphology after plasma membrane permeabilization. In vivo results indicated a specific CD8+ T cell immune response, together with a strong HR according to the Peritoneal Regression Grading Score (PRGS). The effects of nsPEFs on CT-26 were confirmed in a mouse model of CRC with PM.

Oncolytic HSV Therapy Modulates Vesicular Trafficking Inducing Cisplatin Sensitivity and Antitumor Immunity.

Here we investigated the impact of oncolytic herpes simplex virus (HSV) treatment on cisplatin sensitivity of platinum-resistant ovarian cancer, and the impact of the combination on immunotherapy. Therapeutic efficacy of the combination was assessed in platinum-resistant human and murine ovarian cancer peritoneal metastatic mouse models (n = 9-10/group). RNA sequencing along with flow cytometry of splenocytes from treated mice was employed to examine the effect of antitumor immune response (n = 3/group). Anti-PD-1 antibody was performed to evaluate impact on checkpoint inhibition in vivo. Gene Ontology pathway analysis uncovered disruption of cellular extracellular vesicle (EV)-related pathways in infected cells (FDR = 2.97E-57). Mechanistically, we identified reduced expression of transporters expressed on EV implicated in cisplatin efflux. The increased cisplatin retention led to increased cisplatin-DNA adducts, which resulted in micronuclei and the subsequent activation of cGAS-STING pathway with a significant activation of innate immune cells and translated to an increase in antitumor immunity and efficacy. In mice bearing platinum-resistant ovarian cancer, we also observed a feedback induction of PD-L1 on tumor cells, which sensitized combination-treated mice to anti-PD-1 immune checkpoint therapy. To our knowledge, this is the first report to show HSV-induced cisplatin retention in infected cells. The consequential increased damaged DNA was then expelled from cells as micronuclei which resulted in induction of inflammatory responses and education of antitumor immunity. The combination therapy also created an environment that sensitized tumors to immune checkpoint therapy.

Extracellular Vesicles from Cancer-Associated Fibroblasts Containing Annexin A6 Induces FAK-YAP Activation by Stabilizing β1 Integrin, Enhancing Drug Resistance.

Extracellular vesicles (EV) from cancer-associated fibroblasts (CAF) are composed of diverse payloads. Although CAFs impact the aggressive characteristics of gastric cancer cells, the contribution of CAF-EV to gastric cancer progression has not been elucidated. Here, we investigated the molecular mechanism of the changes in gastric cancer characteristics induced by CAF-EV. CAF abundance in gastric cancer tissues was associated with poor prognosis of patients with gastric cancer receiving chemotherapy. Moreover, CAF-EV induced tubular network formation and drug resistance of gastric cancer cells in the extracellular matrix (ECM). Comprehensive proteomic analysis of CAF-EV identified that Annexin A6 plays a pivotal role in network formation and drug resistance of gastric cancer cells in the ECM via activation of β1 integrin-focal adhesion kinase (FAK)-YAP. A peritoneal metastasis mouse model revealed that CAF-EV induced drug resistance in peritoneal tumors, and inhibition of FAK or YAP efficiently attenuated gastric cancer drug resistance in vitro and in vivo. These findings demonstrate that drug resistance is conferred by Annexin A6 in CAF-EV and provide a potential avenue for overcoming gastric cancer drug resistance through the inhibition of FAK-YAP signaling in combination with conventional chemotherapeutics. SIGNIFICANCE: This study elucidates a novel molecular mechanism through which Annexin A6 in CAF-EV activates FAK-YAP by stabilizing β1 integrin at the cell surface of gastric cancer cells and subsequently induces drug resistance. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/16/3222/F1.large.jpg.

Peritoneal Metastatic Cancer Stem Cells of Gastric Cancer with Partial Mesenchymal-Epithelial Transition and Enhanced Invasiveness in an Intraperitoneal Transplantation Model.

Objectives This preliminary study is aimed at enriching and isolating peritoneal metastatic cancer stem cells (pMCSCs) of gastric cancer and assessing their epithelial-mesenchymal transition (EMT) phenotype and invasiveness. Methods Cancer stem cells of human gastric cancer (CSC-hGC) were previously isolated and transfected with green fluorescent protein and luciferase genes to validate the mouse model of peritoneal metastasis established via transplantation. The first and second generations ([G1] and [G2], respectively) of pMCSCs were isolated from intraperitoneally transplanted CSC-hGC (pMCSC-tGC) by spherical culture. CSC and EMT-related markers and regulators in the two generations of intraperitoneally transplanted tumors were examined by immunohistochemistry, immunofluorescence staining, and quantitative PCR. Cell mobility was examined by a transwell assay. Results The nude mouse model of intraperitoneally transplanted CSC-hGC was successful in establishing sequential formation of peritoneal tumors and enrichment of pMCSCs. CD44 and CD54 were consistently expressed in the two generations of transplanted tumors. In vitro cell (migration) assays and immunocytofluorescence assays showed that in pMCSC-tGC[G2], E-cad, Survivin, and Vimentin expression was stable; α-SMA expression was decreased; and OVOL2, GRHL2, and ZEB1 expression was increased. PCR analysis indicated that in pMCSC-tGC[G2], the mRNA expression of E-cad, α-SMA, MMP9, MMP2, and Vimentin was downregulated, while that of ZEB1, OVOL2, and GRHL2 was upregulated. In vivo tumor (homing) assays and immunohistochemical assays demonstrated that in pMCSC-tGC[G2], E-cad and Snail were upregulated, while α-SMA was downregulated. The numbers of migrated and invaded pMCSC-tGC[G1] and pMCSC-tGC[G2] were significantly higher than those of CSC-hGC in migration and invasion assays. Conclusions pMCSCs might be a specific subpopulation that can be sequentially enriched by intraperitoneal transplantation. pMCSCs exhibited a tendency towards partial mesenchymal-epithelial transition, enhancing their invasiveness during homing and the formation of peritoneal tumors. However, these preliminary findings require validation in further experiments.

Establishment and characterization of a cell line and patient-derived xenograft (PDX) from peritoneal metastasis of low-grade serous ovarian carcinoma

Peritoneal spread indicates poor prognosis in patients with serous ovarian carcinoma (SOC) and is generally treated by surgical cytoreduction and chemotherapy. Novel treatment options are urgently needed to improve patient outcome. Clinically relevant cell lines and patient-derived xenograft (PDX) models are of critical importance to therapeutic regimen evaluation. Here, a PDX model was established, by orthotopic engraftment after subperitoneal tumor slurry injection of low-grade SOC, resulting in an early-stage transplantable peritoneal metastasis (PM)-PDX model. Histology confirmed the micropapillary and cribriform growth pattern with intraluminal tumor budding and positivity for PAX8 and WT1. PM-PDX dissociated cells show an epithelial morphotype with a 42 h doubling time and 40% colony forming efficiency, they are low sensitive to platinum derivatives and highly sensitive to paclitaxel (IC50: 6.3 ± 2.2 nM, mean ± SEM). The patient primary tumor, PM, PM-PDX and derived cell line all show a KRAS c.35 G > T (p.(Gly12Val)) mutation and show sensitivity to the MEK inhibitor trametinib in vitro (IC50: 7.2 ± 0.5 nM, mean ± SEM) and in the PM mouse model. These preclinical models closely reflecting patient tumors are useful to further elucidate LGSOC disease progression, therapy response and resistance mechanisms.

Fucosyltransferase 8 plays a crucial role in the invasion and metastasis of pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer. It is an aggressive malignancy associated with poor prognosis because of recurrence, metastasis, and treatment resistance. Aberrant glycosylation of cancer cells triggers their migration and invasion and is considered one of the most important prognostic cancer biomarkers. The current study aimed to identify glycan alterations and their relationship with the malignant potential of PDAC. Using a lectin microarray, we evaluated glycan expression in 62 PDAC samples. Expression of fucosyltransferase 8 (FUT8), the only enzyme catalyzing core fucosylation, was investigated by immunohistochemistry. The role of FUT8 in PDAC invasion and metastasis was confirmed using an in vitro assay and a xenograft peritoneal metastasis mouse model. The microarray data demonstrated that core fucose-binding lectins were significantly higher in carcinoma than in normal pancreatic duct tissues. Similarly, FUT8 protein expression was significantly higher in carcinoma than in normal pancreatic duct tissues. High FUT8 protein expression was significantly associated with lymph-node metastases and relapse-free survival. FUT8 knockdown significantly reduced the invasion in PDAC cell lines and impaired peritoneal metastasis in the xenograft model. The findings of this study provide evidence that FUT8 plays a pivotal role in PDAC invasion and metastasis and might be a therapeutic target for this disease.

Evaluation of a new histological grading system for assessing the response to chemotherapy of peritoneal metastases from colorectal cancer: A mouse model study

This experimental study evaluated the histological response of peritoneal metastases (PM) from colorectal cancer (CRC) after preoperative systemic chemotherapy (pCT). The results demonstrated that the Peritoneal Regression Grade Score could be used in medical practice. AimThe aim was to evaluate the histological criteria used by the tumour regression grade (TRG) and Peritoneal Regression Grade Score (PRGS) for determining the response to chemotherapy (CT), in a mouse model of peritoneal metastases (PM) from colorectal cancer (CRC). MethodsTwenty immunocompetent BALB/c mice were randomized into four groups at day (D) 10 after intraperitoneal (ip) injection with bioluminescent CRC tumour cells (CT26-luc). A histology before treatment group was obtained by sacrifice on D10; the other groups all received one of the following ip treatments over 15 days: 5% glucose (control, G5); 5-fluorouracil (5FU, 0.03 mg/g); or 5FU with oxaliplatin (Ox, 0.006 mg/g). The histological response (HR) was analysed by comparing the histology of PM before and after treatment, using both scores: TRG and PRGS. ResultsAll mice showed limited PM as visualised by bioluminescence and confirmed at the time of sacrifice in the histology before treatment group. The mean peritoneal carcinomatosis index (PCI) was = 8 [6–10], The rate of complete HR was significantly higher in the Ox-5FU group (83.3%) than 5FU group (0%) and G5 group (0%) (p = 0.016). Fibrosis was present only in CT-treated groups (p = 0.05). PCI, ascites volume and haemorrhagic ascites were significantly higher in the G5 group than CT groups (p < 0.05). ConclusionsThe TRG score can be used in practice when we want to compare the HR between the primary tumour and the PMs. The PRGS is a good measure of HR and is correlated with the efficacy of CT.

Abstract 895: The identification of molecular mechanism underlying the progression of gastric cancer peritoneal dissemination by senescent fibroblasts

Abstract Background: Secreted factors from cancer associated fibroblast (CAFs) is likely to be implicated in cancer progression, but the precise mechanism is not fully understood. It is reported that senescent cells survive and secrete some cytokines, so called senescence-associated secretory phenotype (SASP). The purpose of current study is to identify the molecular mechanism underlying the progression of gastric cancer (GC) peritoneal dissemination by CAFs showing SASP. Methods: We examined the senescent state of CAFs activated NFkB signaling by inflammatory cytokines (iCAFs) and evaluated the expression of SASP factors. We investigated the growth ability of GC cell lines treated with iCAFs derived condition medium (CM). We transplanted GC cell lines with intraperitoneal administration to generate peritoneal metastasis mouse model and evaluated the influence of SASP factors on cancer progression. Results: We found that the growth ability of iCAFs decreased and their expression of p16 and p15, which was senescent markers increased. And the comprehensive genomic analysis revealed that iCAFs was highly enriched the senescent related genes and SASP factors related genes. Next, we also found that iCAFs derived CM significantly increased the growth ability of GC cells. Moreover, also in peritoneal metastasis mouse model, iCAFs derived CM remarkably enhanced intraperitoneal tumors. Conclusion: These findings suggest that SASP factors from senescent CAFs, which activated by inflammatory cytokines can promote peritoneal dissemination of GC cells. Citation Format: Tadahito Yasuda, Mayu Koiwa, Tomoyuki Uchihara, Atsuko Yonemura. The identification of molecular mechanism underlying the progression of gastric cancer peritoneal dissemination by senescent fibroblasts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 895.

LncRNA UCA1-Mediated Cdc42 Signaling Promotes Oncolytic Vaccinia Virus Cell-to-Cell Spread in Ovarian Cancer

Oncolytic vaccinia virus (OVV) has demonstrated appropriate safety profiles for clinical development. Although designed to kill cancer cells efficiently, OVV sensitivity varies in individual cancers, and predictive biomarkers of therapeutic responses have not been identified. Here we found that OVV was much more efficient in KFTX paclitaxel-resistant ovarian cancer cells compared to that in KFlow paclitaxel-sensitive cells. Microarray analysis identified long non-coding RNA urothelial carcinoma-associated 1 (UCA1) upregulation, which contributed to both enhanced paclitaxel resistance and OVV spread. In addition, UCA1 expression correlated with efficient OVV spread in other ovarian cell lines and primary cancer cell cultures. When host pathways underlying OVV spread were analyzed, differences were detected in the activation of the Rho GTPase Cdc42, suggesting that filopodia formation enhances OVV cell-to-cell spread and tumor migration. Moreover, we established a clinically relevant mouse model of peritoneal metastasis using KFTX or KFlow cells. Paclitaxel exerted anti-tumor effects on KFlow, but not KFTX, tumors. In mice bearing KFTX cells after paclitaxel failure, OVV treatment induced the regression of residual tumors and improved survival. Our findings demonstrated that UCA1 promotes OVV cell-to-cell spread in ovarian cancer, resulting in enhanced therapeutic outcome.

Intraperitoneal chemotherapy for peritoneal metastases using sustained release formula of cisplatin-incorporated gelatin hydrogel granules.

We previously reported the effectiveness of gelatin microspheres incorporating cisplatin in a mouse model of peritoneal metastases. In this study, we report our new complete sustained-release formula of gelatin hydrogel granules incorporating cisplatin (GHG-CDDP), which exerted a good anti-tumor effect with less toxicity. GHG-CDDP was prepared without organic solvents to enable its future clinical use. The pharmaceutical characterization of GHG-CDDP was performed, and its in vivo degradability was evaluated. The anti-tumor effect was evaluated using a murine peritoneal metastasis model of the human gastric cancer MKN45-Luc cell line. Our new manufacturing process dramatically reduced the initial burst of CDDP release to approximately 2% (wt), while the previous product had a 25-30% initial burst. In intraperitoneal degradation tests, approximately 30% of GHG-CDDP remained in the murine abdominal cavity 7 days after intraperitoneal injection and disappeared within 3 weeks. GHG-CDDP significantly suppressed the in vivo tumor growth (p = 0.02) and prolonged the survival time (p = 0.0012) compared with the control. In contrast, free CDDP did not show a significant therapeutic effect at any dose. Weight loss and hematological toxicity were also significantly ameliorated. GHG-CDDP is a promising treatment option for peritoneal metastases through the complete sustained-release of CDDP with less systemic toxicity.

The anti-mesothelin monoclonal antibody amatuximab enhances the anti-tumor effect of gemcitabine against mesothelin-high expressing pancreatic cancer cells in a peritoneal metastasis mouse model.

Pancreatic cancer often has a very poor prognosis, even after complete resection. The recurrence of hepatic and peritoneal metastases is an important prognostic factor; therefore, the development of improved adjuvant therapy is urgently required. Mesothelin is a cell surface glycoprotein whose expression is restricted to a variety of cancer types, including pancreatic cancer. This expression pattern makes mesothelin an attractive target for cancer therapy, and several agents targeting mesothelin are currently in clinical trials. Here, we used the chimerized high-affinity anti-mesothelin monoclonal antibody amatuximab to investigate its effect on peritoneal metastasis. We used the AsPC-1 pancreatic cancer cell line engineered to express Gaussia luciferase (Gluc), (AsPC-1-Gluc) for in vivo experiments. Results showed that while amatuximab was not directly cytotoxic on an AsPC-1-Gluc tumor cells in a peritoneal metastasis model, it prevented the formation of tumor growth. In combination therapy with gemcitabine, amatuximab exhibited synergistic killing. Our results suggest that blockade of mesothelin by amatuximab may be a useful strategy for preventing the peritoneal dissemination of pancreatic cancer under an adjuvant setting.

Exosomal TRIM3 is a novel marker and therapy target for gastric cancer

BackgroundExosomes are critically involved in cancer development and progression. The exosomal contents have been suggested as ideal cancer biomarkers. In this study, we investigated the expression of exosomal proteins in the serum of gastric cancer patients and their roles in gastric cancer.MethodsThe proteomic profile of exosomes from the serum of gastric cancer patients was detected by using LC-MS/MS. The expression of TRIM3 in exosomes from the serum of gastric cancer patients and healthy controls was assessed by ELISA and western blot. Immunohistochemistry was used to detect TRIM3 expression in gastric cancer tissues and their matching adjacent tissues. The growth and migration abilities of gastric cancer cells with TRIM3 overexpression or knockdown in vitro were evaluated by colony formation assay and transwell migration assay. The effects of TRIM3 overexpression or knockdown on gastric cancer growth and metastasis in vivo were investigated by using subcutaneous xenograft tumor and peritoneal metastasis mouse model. The effects of TRIM3-overexpressing exosomes on gastric cancer growth and metastasis in vitro and in vivo were also evaluated.ResultsWe found that the expression levels of TRIM3 mRNA and protein were decreased in gastric cancer tissues compared to the matched control tissues. In addition, the levels of TRIM3 protein in the serum exosomes of gastric cancer patients were lower than that in healthy controls. We demonstrated that TRIM3 overexpression reduced while TRIM3 knockdown promoted the growth and metastasis of gastric cancer in vitro and in vivo through the regulation of stem cell factors and EMT regulators. Moreover, exosomes-mediated delivery of TRIM3 protein could suppress gastric cancer growth and metastasis in vitro and in vivo.ConclusionsTaken together, our findings suggest that exosomal TRIM3 may serve as a biomarker for gastric cancer diagnosis and the delivery of TRIM3 by exosomes may provide a new avenue for gastric cancer therapy.