Cancer Peritoneal Dissemination Research Articles

Epithelial splicing regulatory protein 1 promotes peritoneal dissemination of ovarian cancer by inducing the formation of circular RNAs modulating epithelial plasticity

Peritoneal metastases prevalently occur in ovarian cancer, deteriorating patient prognosis. During the metastatic cascade, tumor plasticity enables cells to adapt to environmental changes, thereby facilitating dissemination. We previously found that epithelial splicing regulatory protein 1 (ESRP1) is linked to peritoneal metastasis and epithelial-mesenchymal plasticity in ovarian cancer. This study delves into the underlying mechanism. We found that ESRP1 preserves epithelial plasticity in ovarian cancer cells in vitro and in vivo. Functionally, ESRP1 enhances ovarian cancer cell growth and peritoneal dissemination. High-throughput sequencing revealed several ESRP1-related epithelial RNAs, encompassing both linear and circular forms. Specifically, ESRP1 triggers the cyclization of circPAFAH1B2 and circUBAP2 through binding to the GGU sequences in adjacent introns. The two ESRP1-induced circular RNAs stabilize DKK3 and AHR mRNAs, which are critical for epithelial plasticity, through interaction with IGF2BP2. Collectively, ESRP1 triggers the formation of circPAFAH1B2 and circUBAP2, which in turn stabilizes DKK3 and AHR through IGF2BP2 binding, thereby modulating the epithelial plasticity and aiding the peritoneal spread of ovarian cancer cells. The findings unveiled a biological network, orchestrated by ESRP1, that governs the epithelial-mesenchymal plasticity of ovarian cancer cells, emphasizing the therapeutic potential of ESRP1 and its induced circular RNAs for ovarian cancer treatment.

G-CSF induces neutrophil extracellular traps formation and promotes ovarian cancer peritoneal dissemination.

Epithelial ovarian cancer is characterized by aggressive peritoneal dissemination. Neutrophils are mobilized to peritoneal cavity in some patients with ovarian cancer dissemination; however, its pathological significance remains unknown. This study aimed to investigate the role of neutrophil extracellular traps (NETs) in ovarian cancer dissemination. We conducted a retrospective analysis of clinical data and samples from 340 patients with ovarian cancer who underwent primary surgery between 2007 and 2016 at the Osaka University Hospital. In vitro, NETs formation was induced by stimulating human peripheral neutrophils. The human ovarian cancer cell line, OVCAR8, was cocultured with NETs. For an ovarian cancer dissemination mouse model, we performed an intraperitoneal injection of OVCAR8 cells into nude mice. The association between NETs and peritoneal dissemination was explored, and model mice were treated with the PAD4 inhibitor GSK484 to assess antitumor efficacy. Neutrophilia (neutrophil count >7000/mm3) correlated with shorter survival, advanced peritoneal dissemination, elevated granulocyte colony-stimulating factor (G-CSF) levels, increased neutrophil count in ascites, and augmented NETs foci in peritoneal dissemination sites. In vitro assays revealed that G-CSF stimulated neutrophils to form NETs, promoting cancer cell adhesion. In vivo investigations revealed that G-CSF-producing tumor-bearing mice had accelerated peritoneal dissemination and poor prognosis. NETs formation was pathologically observed at the peritoneal dissemination sites. Inhibition of NETs formation by GSK484 significantly delayed peritoneal dissemination in vivo. In conclusion, G-CSF was associated with intra-abdominal NETs formation and increased peritoneal dissemination. NETs represent potential therapeutic targets for ovarian cancer, particularly in patients with neutrophilia.

Contributions of endoscopic ultrasonography-guided tissue acquisition (EUS-TA) to the diagnostics of biliary stricture and gallbladder lesions.

Endoscopic ultrasonography (EUS) provides high spatial resolution and more detailed images than other diagnostic modalities. Furthermore, EUS-guided tissue acquisition (EUS-TA), such as EUS-guided fine needle aspiration or biopsy (EUS-FNA/FNB), is an indispensable tool in pancreaticobiliary disease diagnostics, supporting a conclusive pathological diagnosis. In this review, we evaluate the current status and the usefulness of EUS-TA for the diagnostics of the following biliary tract diseases: (A) biliary stricture diagnostics, (B) biliary tract cancer (BTC) itself, and (C) staging of advanced BTC. Previous reports have shown that EUS-FNA for biliary lesions is a safe procedure that is useful in differentiating biliary cancer from benign lesions and in the staging of BTC. On the other hand, the diagnostic performance of EUS-TA for bile duct lesions is reported to be similar to that of transpapillary biopsy. Overall, EUS-TA for biliary lesions may be a safe and effective method, but it should be performed with an understanding of the risk of serious adverse events such as bile leakage and peritoneal dissemination of cancer. It is recommended for distal biliary stricture lesions for which endoscopic retrograde cholangiopancreatography cannot confirm the diagnosis or gallbladder lesions if they do not require the needle to pass through the biliary lumen.

Involvement of Protease-Activated Receptor2 Pleckstrin Homology Binding Domain in Ovarian Cancer: Expression in Fallopian Tubes and Drug Design.

Studying primordial events in cancer is pivotal for identifying predictive molecular indicators and for targeted intervention. While the involvement of G-protein-coupled receptors (GPCRs) in cancer is growing, GPCR-based therapies are yet rare. Here, we demonstrate the overexpression of protease-activated receptor 2 (PAR2), a GPCR member in the fallopian tubes (FTs) of high-risk BRCA carriers as compared to null in healthy tissues of FT. FTs, the origin of ovarian cancer, are known to express genes of serous tubal intraepithelial carcinoma (STICs), a precursor lesion of high-grade serous carcinoma (HGSC). PAR2 expression in FTs may serve as an early prediction sensor for ovarian cancer. We show now that knocking down Par2 inhibits ovarian cancer peritoneal dissemination in vivo, pointing to the central role of PAR2. Previously we identified pleckstrin homology (PH) binding domains within PAR1,2&4 as critical sites for cancer-growth. These motifs associate with PH-signal proteins via launching a discrete signaling network in cancer. Subsequently, we selected a compound from a library of backbone cyclic peptides generated toward the PAR PH binding motif, namely the lead compound, Pc(4-4). Pc(4-4) binds to the PAR PH binding domain and blocks the association of PH-signal proteins, such as Akt or Etk/Bmx with PAR2. It attenuates PAR2 oncogenic activity. The potent inhibitory function of Pc(4-4) is demonstrated via inhibition of ovarian cancer peritoneal spread in mice. While the detection of PAR2 may serve as a predictor for ovarian cancer, the novel Pc(4-4) compound may serve as a powerful medicament in STICs and ovarian cancer. This is the first demonstration of the involvement of PAR PH binding motif signaling in ovarian cancer and Pc(4-4) as a potential therapy treatment.

Helicobacter pylori-induced fibroblast-derived Serpin E1 promotes gastric cancer growth and peritoneal dissemination through p38 MAPK/VEGFA-mediated angiogenesis

BackgroundFibroblasts, especially cancer-associated fibroblasts (CAFs), represent the predominant stromal cell population in the tumor microenvironment and have an important function in tumorigenesis by interacting with tumor cells. However, their interaction remains elusive in an inflammatory tumor microenvironment induced by Helicobacter pylori (H. pylori).MethodsThe expression of Serpin family E member 1 (Serpin E1) was measured in fibroblasts with or without H. pylori infection, and primary gastric cancer (GC) cells. Serpin E1 knockdown and overexpression fibroblasts were generated using Serpin E1 siRNA or lentivirus carrying Serpin E1. Co-culture models of fibroblasts and GC cells or human umbilical vein endothelial cells (HUVECs) were established with direct contact or the Transwell system. In vitro functional experiments and in vivo tumorigenesis assay were employed to study the malignant behaviors of GC cells interacting with fibroblasts. ELISA was used for quantifying the levels of Serpin E1 and VEGFA in the culture supernatant. The tube formation capacity of HUVECs was assessed using a tube formation assay. Recombinant human Serpin E1 (recSerpin E1), anti-Serpin E1 antibody, and a MAPK pathway inhibitor were utilized to treat HUVECs for elucidating the underlying molecular mechanisms.ResultsSerpin E1 was predominantly expressed in gastric CAFs. H. pylori infection significantly enhanced the expression and secretion of Serpin E1 by CAFs. Both fibroblast-derived Serpin E1 and recSerpin E1 enhanced the growth, invasion, and migration of GC cells, along with increased VEGFA expression and tube formation in HUVECs. Furthermore, the co-inoculation of GC cells and fibroblasts overexpressing Serpin E1 triggered the expression of Serpin E1 in cancer cells, which facilitated together xenograft tumor growth and peritoneal dissemination of GC cells in nude mice, with an increased expression of Ki67, Serpin E1, CD31 and/or VEGFA. These processes may be mediated by Serpin E1-induced migration and p38 MAPK/VEGFA-mediated angiogenesis of HUVECs.ConclusionH. pylori infection induces Serpin E1 expression in fibroblasts, subsequently triggering its expression in GC cells through their interaction. Serpin E1 derived from these cells promotes the migration and p38 MAPK/VEGFA-mediated angiogenesis of HUVECs, thereby facilitating GC growth and peritoneal metastasis. Targeting Serpin E1 signaling is a potential therapy strategy for H. pylori-induced GC.

The impact of body weight on the development of peritoneal metastases in colorectal cancer patients: results from a nationwide cohort study

BackgroundObesity is a major global health problem and an important risk factor for colorectal cancer (CRC) is increased body weight. Obesity plays a role in the peritoneal dissemination of cancer; however, it is unclear whether this also applies for peritoneal dissemination of CRC. The purpose of this study was to provide insight in the role of obesity on the peritoneal dissemination of colorectal cancer.MethodsOf all patients diagnosed with CRC in the Netherlands in the first half of 2015, follow-up data was completed in 2019. Weight at time of primary diagnosis was categorized as underweight, normal weight, overweight, or obese. Logistic regression modelling was used to assess the association between weight and the presence of synchronous colorectal peritoneal metastases (CPM), and Cox regression modelling was used to assess the association between weight and metachronous CPM. Patient and tumor characteristics were taken into account. The analyses were adjusted for tumor stage, nodal stage, tumor location, and tumor histology.ResultsIn total, 6436 patients were included in this study. Two-hundred ninety-three (4.6%) patients presented with synchronous CPM at the time of primary diagnosis, while another 278 (5.1%) patients developed metachronous CPM after a median time of 16.5 months. Univariable and multivariable logistic regression modelling did not identify an effect of weight on the presence of synchronous CPM. Neither underweight (odds ratio [OR] 1.10, 95% CI 0.48–2.54), nor overweight (OR 0.96, 95% CI 0.71–1.29), or obesity (OR 0.84, 95% CI 0.56–1.26) was either positively or negatively associated with the presence of synchronous peritoneal metastases as compared to normal weight. Univariable and multivariable Cox regression modelling did not identify an effect of weight on the development of metachronous CPM. Neither underweight (HR 0.162, 95% CI 0.02–1.16), nor overweight (HR 1.07, 95% CI 0.82–1.39), or obesity (HR 1.02, 95% CI 0.73–1.16) was either positively or negatively associated with the presence of synchronous peritoneal metastases as compared to normal weight.ConclusionCRC patients who are overweight or obese are not more at risk for the presence of synchronous CPM nor development of metachronous CPM than their normal-weight counterparts.

Exosomes secreted by ST3GAL5high cancer cells promote peritoneal dissemination by establishing a premetastatic microenvironment.

Peritoneal dissemination of cancer affects patient survival. The behavior of peritoneal mesothelial cells (PMCs) and immune cells influences the establishment of a microenvironment that promotes cancer cell metastasis in the peritoneum. Here, we investigated the roles of lactosylceramide alpha-2,3-sialyltransferase (ST3G5; also known as ST3GAL5 and GM3 synthase) in the exosome-mediated premetastatic niche in peritoneal milky spots (MSs). Exosomes secreted from ST3G5high cancer cells (ST3G5high -cExos) were found to contain high levels of hypoxia-inducible factor 1-alpha (HIF1α) and accumulated in MSs via uptake in macrophages (MΦs) owing to increased expression of sialic acid-binding Ig-like lectin 1 (CD169; also known as SIGLEC1). ST3G5high -cExos induced pro-inflammatory cytokines and glucose metabolic changes in MΦs, and the interaction of these MΦs with PMCs promoted mesothelial-mesenchymal transition (MMT) in PMCs, thereby generating αSMA+ myofibroblasts. ST3G5high -cExos also increased the expression of immune checkpoint molecules and T-cell exhaustion in MSs, which accelerated metastasis to the omentum. These events were prevented following ST3G5 depletion in cancer cells. Mechanistically, ST3G5high -cExos upregulated chemokines, including CC-chemokine ligand 5 (CCL5), in recipient MΦs and dendritic cells (DCs), which induced MMT and immunosuppression via activation of signal transducer and activator of transcription 3 (STAT3). Maraviroc, a C-C chemokine receptor type 5 (CCR5) antagonist, prevented ST3G5high -cExo-mediated MMT, T-cell suppression, and metastasis in MSs. Our results suggest ST3G5 as a suitable therapeutic target for preventing cExo-mediated peritoneal dissemination.

The apron of the greater omentum of gastric cancer patients contains various lymphoid structures including lymph nodes

PurposeTo gain more insight into the pattern of peritoneal cancer dissemination and optimize cancer treatment, it is important to improve our understanding of the omental lymphatic system. Although omental milky spots (OMSs) are considered the only lymphoid structures in the omentum, clinical studies mention the presence of lymph nodes (LNs) as well. This discrepancy may be explained by the fact that OMSs are highly dynamic structures and may erroneously be mistaken for LNs. The aim of this study was to evaluate the lymphoid structures, and mainly the presence of lymph nodes, in the apron of the greater omentum. Basic proceduresIn this study, diagnostic samples of the greater omentum of 17 gastric cancer patients that were previously reported to contain LNs were re-evaluated for their presence. Paraffin embedded omental samples were stained with Picrosirius red, smooth muscle actin and CD20 and CD3, and microscopically re-examined according to predefined criteria to distinguish OMSs from LNs. Main findingsPathology records reported 47 LNs in 17 patients. Upon re-evaluation, 20/47 LNs could be classified as true LNs and were located in both the upper and lower quadrants of the greater omentum. The other 27 structures could not be classified as LNs or OMSs and were defined as intermediate lymphoid structures. ConclusionsThe omental apron of gastric cancer patients contains LNs and intermediate lymphoid structures, the latter most likely representing activated OMSs. These observations underline that our understanding of the lymphatic system of the greater omentum is incomplete and requires additional studies to gain further insight in its structure and function in both health and disease.

A263 MODULATION OF THE GUT MICROBIOTA TO PREVENT LOCAL ANASTOMOTIC TUMORS AND DISTANT METASTASIS IN COLORECTAL CANCER SURGERY

Abstract Background Colorectal cancer (CRC) recurrence is a leading cause of mortality worldwide. It has been suggested that poor anastomotic healing and leakage (AL) after surgery allows cancer cells to implant at the anastomotic site thereby increasing the risk of local cancer recurrence and metastatic spread in the peritoneum and to extraintestinal organs. We have previously showed that inulin, a well-known prebiotic, improves anastomotic healing and strengthens the gut barrier. Purpose The objective of the this study was to investigate the relationship between the promotion of postoperative intestinal healing using inulin and local and distant cancer recurrence. Method A 10-years' retrospective review of AL and non-AL cases after CRC surgery was performed in our institution. The effect of dietary supplementation with inulin on the occurrence of local anastomotic tumors was assessed in a mouse model inoculated with tumor cells directly in the gut lumen after colonic surgery. We also investigated in mice whether inulin may prevent metastatic spread and growth of tumor cells in the liver by transplanting CRC cells surgically into the spleen. Result(s) Patients experiencing AL displayed significantly lower overall survival and more cancer recurrence and progression compared to non-AL patients. Poor anastomotic healing in mice led to larger anastomotic tumors and peritoneal cancer dissemination. Inulin supplementation significantly inhibited local tumor implantation at the anastomotic site, and metastatic spread to the peritoneum and liver. Inulin increased the production of beneficial short-chain fatty acids, reinforced the gut barrier function and alleviated systemic inflammation in mice. Conclusion(s) Anastomotic leak was associated with worse oncological outcomes in patients and mice. Inulin was shown to reinforce the gut barrier, decrease the implantation of cancer cells at the anastomosis, and to prevent tumor dissemination and progression of liver metastasis. This paves the way toward future clinical trials in which such supplementation may be used to promote better oncological outcomes. Please acknowledge all funding agencies by checking the applicable boxes below CIHR, Other Please indicate your source of funding; CRS, FRQS Disclosure of Interest None Declared

Visfatin increases the invasive potential of ovarian granulosa tumor spheroids by reprogramming glucose metabolism.

Visfatin is an adipokine with nicotinamide phosphoribosyltransferase (NAMPT) activity, the concentration of which is higher in ascitic fluid than in serum, and is associated with ovarian cancer peritoneal dissemination. Furthermore, potentially important effects of visfatin on glucose metabolism have been previously reported. However, the mechanism underlying the effects of visfatin on ovarian cancer cell invasion, and whether this involves altered glucose metabolism, has not been elucidated. Here we tested the hypothesis that visfatin, which can reprogram cancer metabolism, promotes invasion by ovarian cancer spheroids. Visfatin increased glucose transporter (GLUT)1 expression and glucose uptake in adult granulosa cell tumor-derived spheroid cells (KGN), and also increased the activities of hexokinase 2 and lactate dehydrogenase. We showed a visfatin-induced increase in glycolysis in KGN cells. Moreover, visfatin increased the potential invasiveness of KGN spheroid cells by upregulating MMP2 (matrix metalloproteinase 2) and downregulating CLDN3 and CLDN4 (claudin 3 and 4) gene expression. Interestingly, an inhibitor of GLUT1 (STF-31) and lactate dehydrogenase (LDHA) abolished the stimulatory effect of visfatin on the potential invasiveness of KGN cells. More importantly, silencing expression of the NAMPT gene in KGN cells demonstrated its important effect on glycolysis and invasiveness in adult granulosa cell tumor cells. In summary, visfatin appears to increase adult granulosa cell tumor invasiveness through effects on glucose metabolism, and to be an important regulator of glucose metabolism in these cells.

Intracavitary adoptive transfer of IL-12 mRNA-engineered tumor-specific CD8+ T cells eradicates peritoneal metastases in mouse models

ABSTRACT Previous studies have shown that local delivery of tumor antigen-specific CD8+ T lymphocytes engineered to transiently express single-chain IL-12 mRNA is highly efficacious. Peritoneal dissemination of cancer is a frequent and often fatal patient condition usually diagnosed when the tumor burden is too large and hence uncontrollable with current treatment options. In this study, we have modeled intracavitary adoptive T cell therapy with OVA-specific OT-I T cells electroporated with IL-12 mRNA to treat B16-OVA and PANC02-OVA tumor spread in the peritoneal cavity. Tumor localization in the omentum and the effects of local T-cell encounter with the tumor antigens were monitored, the gene expression profile evaluated, and the phenotypic reprogramming of several immune subsets was characterized. Intraperitoneal administration of T cells promoted homing to the omentum more effectively than intravenous administration. Transient IL-12 expression was responsible for a favorable reprogramming of the tumor immune microenvironment, longer persistence of transferred T lymphocytes in vivo, and the development of immunity to endogenous antigens following primary tumor eradication. The efficacy of the strategy was at least in part recapitulated with the adoptive transfer of lower affinity transgenic TCR-bearing PMEL-1 T lymphocytes to treat the aggressive intraperitoneally disseminated B16-F10 tumor. Locoregional adoptive transfer of transiently IL-12-armored T cells appears to offer promising therapeutic advantages in terms of anti-tumor efficacy to treat peritoneal carcinomatosis.

Obesity contributes to the stealth peritoneal dissemination of ovarian cancer: a multi-institutional retrospective cohort study.

The clinical significance of a higher BMI on the prognosis of ovarian cancer remains controversial; therefore, a more detailed analysis is demanded. This study investigated the impact of BMI on peritoneum-specific recurrence to clarify the involvement of adipose tissue in the proliferation of cancer cells at sites of peritoneal dissemination. Among 4,730 patients with malignant ovarian tumors, 280 diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage IIB to IIIC epithelial ovarian cancer and who underwent complete resection in the primary surgery were included in the present study. There were 42, 201, and 37 women in the low, normal, and high BMI groups, respectively. Peritoneum-specific recurrence-free survival and overall survival were both significantly shorter in patients with a high BMI than in those with a normal BMI (p=0.028 and 0.018, respectively). No significant differences were observed in the distribution of sites of recurrence between these two groups. A multivariate analysis identified obesity as an independent prognostic factor in addition to pT3 tumor staging and positive ascites cytology. Patients with a high BMI had a significantly worse prognosis than those with a normal BMI, and peritoneal adipose tissue may have contributed to this difference.

Inhibition of the mToR pathway with everolimus can modulate heat shock genes and ERCC1 gene expression and improves outcomes on serous ovarian cancer in HIPEC in vitro model.

e17541 Background: Worldwide, epithelial ovarian cancer accounts for a significant percentage of malignancies and is the most lethal neoplasm of the gynecological system, mainly due to silent manifestation and late diagnosis. Predominantly, around 70% of newly diagnosed women with epithelial ovarian cancer have the locally advanced or metastatic stage (III/IV). The extensive peritoneal dissemination of epithelial ovarian cancer might occur at the time of primary tumor diagnosis or related to disease relapse after previous treatment. Therefore, understanding the dynamic of peritoneal dissemination is of utmost importance, as peritoneal carcinomatosis is frequently associated with disease morbidity and mortality. Methods: In this study, we cultivated ovarian cancer cells using the OV-90 cell line (high-grade serous) and assessed citoxicity using MTT assay. Initially, the ovarian cancer cells were treated with everolimus 18 nM (37˙C) for 24 hours for both experimental and control groups. Subsequently, two experimental groups were treated with cisplatin in normothermia (Group 1) and hyperthermia (Group 2) (37˙C and 41˙C, respectively) while the control group was treated with phosphate-buffered saline solution 1X at 37˙C (Group 3) and 41˙C (Group 4) for 24 hours. After the first treatment, we re-supplemented each group under the same beforementioned conditions and incubated it for three additional hours. Moreover, the RNA extracts of each sample set were submitted to RT-PCR for the obtention of the qRT-PCR material. Lastly, we compared the expression of the ERCC1 gene and heat shock genes amongst the different intervention groups. Results: There statistical difference concerning cytotoxicity between treatment with everolimus and heated cisplatin versus treatment with everolimus and cisplatin in normothermia. We observed that the ERCC1 and TRAP 1 genes were downregulated in OV-90 cell lines under heated conditions compared to the normothermia group. Conclusions: The use of everolimus in HIPEC in vitro model increases the cytotoxic response and suggest that inhibition of the mTOR pathway modulates the expression of heat shock genes e ERCC1 gene improving outcomes. Nevertheless, there is still a need for studies evaluating the effectiveness of everolimus in preclinical trials under hyperthermic conditions.

Removal of small extracellular vesicles inhibits the progression of peritoneal dissemination in gastric cancer.

The prognosis of gastric cancer patients with peritoneal dissemination is extremely poor and effective treatment for peritoneal dissemination has not been established. Gastric cancer-derived small extracellular vesicles play an important role in the development of a favorable microenvironment for peritoneal metastasis and progression of peritoneal dissemination. Here, we aimed to investigate the transformation of gastric cancer cells by removing gastric cancer-derived small extracellular vesicles and to develop a novel therapy for inhibiting peritoneal dissemination. Gastric cancer cells were cultured in medium containing gastric cancer- and peritoneal mesothelium-derived small extracellular vesicles and in medium from which small extracellular vesicles were removed by ultracentrifugation. Cell function assays were performed in vitro, and the alternations in gene expression in gastric cancer cells were analyzed. The inhibitory effect of intraperitoneal lavage on peritoneal dissemination was investigated in vivo as a method to remove gastric cancer-derived small extracellular vesicles. Removal of gastric cancer-derived small extracellular vesicles suppressed the proliferative and migrative abilities of gastric cancer cells and the adhesion of gastric cancer cells to peritoneal mesothelial cells. It altered the expression of several genes related to the cell cycle and epithelial-mesenchymal transition pathways of gastric cancer cells, leading to the inhibition of gastric cancer cell growth and peritoneal dissemination in vivo. Our study provides novel insights into a novel therapy for inhibiting the peritoneal dissemination of gastric cancer by targeting gastric cancer-derived small extracellular vesicles to improve the prognosis of gastric cancer patients with peritoneal metastasis.

Integration of exosomal miR-106a and mesothelial cells facilitates gastric cancer peritoneal dissemination

BackgroundMetastatic organotropism is considered the end stage of malignancy with the mechanism still have some mysteries that have not been disclosed. Although the role of miR-106a is well studied, its involvement in the formation of peritoneal metastasis transported by exosomes is less discussed. MethodsGastric cancer (GC)-derived exosomes were identified by transmission electron microscopy and the integration with peritoneal mesothelial cells (PMC) was confirmed by PKH-26 staining. Cell phenotype was assessed by EdU and flow cytometry. MiR-106a and its targets were authenticated by luciferase reporter assay. The mesothelial-to-mesenchymal transition (MMT) and extracellular matrix (ECM) degeneration were determined and morphological transformation was measured by transwell assay. Immunodeficient mouse was conducted to investigate the tumorigenesis and tumor growth. The final was tissue analysis. ResultsMiR-106a enrichment in GC-exosomes can be delivered and integrated into PMC to establish a proper pre-metastatic niche (PMN). We found that PMC could internalize exosomal-miR-106a and lead to increased apoptotic rate and decreased proliferative vitality. The direct target Smad7 and TIMP2 were proved to be effectively reduced by translocation of exosomal miR-106a. We confirmed that exosomal miR-106a was able to induce MMT and accelerate ECM through targeting Smad7 and TIMP2 to activate TGF-β pathway. Animal model investigated that the tumorigenesis and tumor growth could be influenced by exosomes, and exosomal-miR-106a could promote the formation of xenograft tumor. Tissue analysis verified the ectopic miR-106a expression in gastric cancer metastasis. ConclusionOur data suggest that exosomal miR-106a facilitates gastric cancer peritoneal dissemination by integrating PMC to destroy mesothelial barrier.

Abstract 2905: The relationship between peritoneal dissemination of gastric cancer & exosome

Abstract Introduction: In recent years, studies of exosomes have progressed rapidly, suggesting a connection to various physiological functions and pathogenesis. The exosomes are small extracellular vesicles with a diameter of 30 to 100 nm surrounded by lipid bilayers, and are attracting attention as a new cell-cell communication medium for carrying lipids, proteins, RNA, etc. in vivo. In addition, in exosomes released by cancer cells, it contains a large number of molecules related to angiogenesis and immunosuppression. It is believed to contribute to building microenvironments suitable for cancer cell growth and promoting cancer progression. Therefore, we focused on exosomes derived from gastric cancer cells, the action of gastric cancer cells, further constructed a gastric cancer peritoneal dissemination mouse model, the action of exosomes in gastric cancer peritoneal metastasis mechanism was examined in vitro, in vivo, respectively. Method: Exosome Isolation Kit was used to extract exosomes from each gastric cancer cell line MKN-1, MKN-45, MKN-45 GFP. The determination of exosomes was carried out using Nano-drop®. Cell adhesion in exosome-treated and non-administered groups were analyzed by colony forming assay. Cell proliferation ability was analyzed using cell proliferation assay method. In vivo, we examined whether the degree of peritoneal dissemination was made using live cell imaging using fluorescent cells. MKN-45 GFP was intraperitoneally administered to BALB/c-nu mice. On days 0, 5, 10, 15, 20, groups were prepared in which 25 µg/500 µl of exosome was administered intraperitoneally and groups in which the same amount of PBS was administered intraperitoneally. In addition, MKN-45 GFP was subcutaneously injected into BALB/c-nu mice to create MKN-45 GFP tumors, which were divided into small horns and transplanted to the stomach walls of BALB/c-nu mice. In the same way as the previous method, we prepared a group in which 25 µg/500 µl exosome was intraperitoneally administered on days 0, 5, 10, 15, 20 and a group in which the same amount of PBS was intraperitoneally administered. We performed a visual comparison of transplanted cancer cells and peritoneal dissemination of cancer. Results and Discussion: The results of the colony forming assay method suggest that exosomes derived from gastric cancer cells have the effect of promoting colony formation ability of cancer cells. We evaluate the results of peritoneal seeding model mice in this study, and further proceed with the analysis of miRNA extraction and analysis from exosomes derived from gastric cancer cells, and cell adhesion of cancer cells under high concentrations of exosomes. Citation Format: Kazuya Kinoshita. The relationship between peritoneal dissemination of gastric cancer & exosome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2905.

Bufalin inhibits peritoneal dissemination of gastric cancer through endothelial nitric oxide synthase-mitogen-activated protein kinases signaling pathway.

Peritoneal dissemination threatens the survival of patients with gastric cancer (GC). Bufalin is an extract of traditional Chinese medicine, which has been proved to have anticancer effect. The target of bufalin in suppressing gastric cancer peritoneal dissemination (GCPD) and the underlying mechanism are still unclear. In this research, GC cell line MGC-803 and high-potential peritoneal dissemination cell line MKN-45P were treated with bufalin or L-NAME. Malignant biological behavior and protein level of GC cell lines were detected with MTT, wound healing, transwell, adhesion, and western blotting. Bioinformatics analysis and patient tissues were used to verify the role of endothelial nitric oxide synthase (NOS3) in GC. Mice model was used to assess the effect of bufalin and role of NOS3 in vivo. We found that bufalin inhibited the proliferation, invasion, and migration in GC cell lines. NOS3, which was an independent prognostic factor of GC patients, was predicted to be a potential target of bufalin. Further experiments proved that bufalin reduced the phosphorylation of NOS3, thereby inhibiting the mitogen-activated protein kinase (MAPK) signaling pathway, and ultimately suppressed GCPD by inhibiting EMT process. In conclusion, NOS3 was a potential therapeutic target and prognostic biomarker of GC. Bufalin could suppress GCPD through NOS3-MAPK signaling pathway, which provided more evidence support for intraperitoneal perfusion of bufalin to treat GCPD.

Oxaliplatin-related interstitial pneumonia with high-grade fever and relative bradycardia as the presenting signs: a case report

BackgroundAlthough drug-induced interstitial pneumonia is a well-known adverse side-effect of cancer chemotherapy, the disease is difficult to detect in the early phase. We report a case of oxaliplatin-induced interstitial pneumonia in which eosinophilia and high-grade fever with relative bradycardia were useful presenting signs for the early diagnosis.Case presentationA 76-year-old Japanese woman with postoperative recurrent rectal cancer (peritoneal dissemination and liver metastasis) was admitted to our hospital because of productive cough and consolidation on thoracic computed tomography (CT) images. Two months prior to the consultation, she had started chemotherapy (fluorouracil, oxaliplatin, and bevacizumab). After finishing three courses of chemotherapy, she developed fever and was noted to have relative bradycardia. After another two courses of chemotherapy, she developed productive cough, chest discomfort, and high-grade fever. At this time, thoracic CT revealed patchy areas of consolidation distributed predominantly in the periphery. Despite the administration of tazobacterium/piperacillin, the consolidation seen on CT scans gradually worsened. Fiberoptic bronchoscopy was performed, and bronchoalveolar lavage fluid analysis showed increased lymphocytes, eosinophils, and total cell count but a low CD4/ CD8 ratio. No specific pathogen was identified. With a diagnosis of interstitial pneumonia, prednisolone was started and chemotherapy was temporarily discontinued. Her productive cough gradually decreased, and the infiltrative shadows on the thoracic CT scans improved.ConclusionAlthough cases of oxaliplatin-related pneumonia with complicating relative bradycardia are not uncommon, drug-induced interstitial pneumonia should be taken into account in the differential diagnosis. In this case, an increased circulating eosinophil count and high-grade fever with relative bradycardia were the first signs of drug-induced interstitial pneumonia.

Hyperthermic intraperitoneal chemotherapy in prevention of gastric cancer metachronous peritoneal metastases: a systematic review.

Gastric cancer progression resulting in metachronous peritoneal metastasizing is almost always associated with an adverse prognosis. This review discusses various options of preventing metachronous peritoneal metastases in radically operated gastric cancer patients. Also examined are different hyperthermic intraperitoneal chemotherapy (HIPEC) regimens employed in gastric cancer treatment, postoperative morbidity and mortality rates and long-term treatment outcomes. The authors also review their own experience of using HIPEC based on the combination of cisplatin and doxorubicin in doses of 50 mg/m2 at 42 °C for 1 h to prevent gastric cancer peritoneal dissemination. As a result, progression-free survival rose from 19.6%±5.6% to 47.1%±6.3% (Plog-rank <0.001) and dissemination-free survival-from 22.7%±6.0% to 51.9%±6.3% (Plog-rank <0.001). It is noted that the combination of the described HIPEC regimen with systemic chemotherapy helped raise metastases-free 3-year survival rate to up to 91.0%±9.0% (Plog-rank =0.025) compared with 48.6%±6.4% for patients who underwent only a combined surgery/HIPEC treatment. HIPEC is a promising combined treatment strategy for radically operated gastric cancer patients that can improve patient survival and decrease peritoneal dissemination rate. However, the number of randomized studies on adjuvant HIPEC are still insufficient for a subgroup assessment of efficacy of the given chemotherapy regimens and generation of evidence-based recommendations on the individual use of chemotherapy agents and their combinations, and HIPEC procedural techniques. Further prospective randomized studies are needed to assess the practicability of complementing HIPEC with adjuvant systemic chemotherapies.

Perioperative Management of Gastric Cancer Patients Treated With (Sub)Total Gastrectomy, Cytoreductive Surgery, and Hyperthermic Intraperitoneal Chemotherapy (HIPEC): Lessons Learned.

The PERISCOPE I study was designed to assess the safety and feasibility of (sub)total gastrectomy, cytoreductive surgery (CRS), and hyperthermic intraperitoneal chemotherapy (HIPEC) with oxaliplatin and docetaxel for gastric cancer patients who have limited peritoneal dissemination. The current analysis investigated changes in perioperative management together with their impact on postoperative outcomes. Patients with resectable gastric cancer and limited peritoneal dissemination were administered (sub)total gastrectomy, CRS, and HIPEC with oxaliplatin (460mg/m2) and docetaxel (escalating scheme: 0, 50, 75mg/m2). Of the 25 patients who completed the study protocol, 14 were treated in the dose-escalation cohort and 11 were treated in the expansion cohort (to optimize perioperative management). A significant proportion of the patients in the dose-escalation cohort (n = 7, 50%) had ileus-related complications. In this cohort, enteral nutrition was started immediately after surgery at 20ml/h, which was increased on day 1 to meet nutritional needs. In the expansion cohort, enteral nutrition was administered at 10ml/h until day 3, then restricted to 20ml/h until day 6, supplemented with total parenteral nutrition to meet nutritional needs. Ileus-related complications occurred for two patients (18%) of the expansion cohort. The intensive care unit (ICU) readmission rate decreased from 50 (n = 7) to 9% (n = 1; p = 0.04). The implementation of a strict nutritional protocol during the PERISCOPE I study was associated with a decrease in postoperative complications. Based on these results, a perioperative care path was described for the gastric cancer HIPEC patients in the PERISCOPE II study.