Mesothelial cells with mesenchymal features enhance peritoneal dissemination by forming a protumorigenic microenvironment.

Malignant ascites accompanied by peritoneal dissemination contain various factors and cell populations as well as cancer cells; however, how the tumor microenvironment is shaped in ascites remains unclear. Single-cell proteomic profiling and a comprehensive proteomic analysis are conducted to comprehensively characterize malignant ascites. Here, we find defects in immune effectors along with immunosuppressive cell accumulation in ascites of patients with gastric cancer (GC) and identify five distinct subpopulations of CD45(-)/EpCAM(-) cells. Mesothelial cells with mesenchymal features in CD45(-)/EpCAM(-) cells are the predominant source of chemokines involved in immunosuppressive myeloid cell (IMC) recruitment. Moreover, mesothelial-mesenchymal transition (MMT)-induced mesothelial cells strongly express extracellular matrix (ECM)-related genes, including tenascin-C (TNC), enhancing metastatic colonization. These findings highlight the definite roles of the mesenchymal cell population in the development of a protumorigenic microenvironment to promote peritoneal dissemination.

Hemodynamic Variability During Drainage of Large Volumes of Malignant Ascites in Patients With Cancer.

This study compared the variability in mean arterial pressure (MAP) during drainage of ascites in patients with cancer who underwent drainage of a large (5-10 L) or small (<5 L) volume of ascites. We prospectively enrolled 50 patients scheduled for cell-free and concentrated ascites reinfusion therapy. Equivalence was considered to be established if the 95% confidence interval (95% CI) for the highest variability rate of MAP was within ±20%. The median volume of ascites removed was 3.30 L (95% CI [2.84, 4.40]) in the small-drainage-volume group (n = 15) and 6.75 L (95% CI [6.40, 7.30]) in the large-drainage-volume group (n = 34). The 95% CIs for the highest variability rates in MAP ranged from -19.60 to -6.23 and from -19.16 to -12.95 (p = .594), respectively, indicating equivalence. These findings indicate that variability in MAP during drainage of ascites is not dependent on drainage volume.

ARHGAP-RhoA signaling provokes homotypic adhesion-triggered cell death of metastasized diffuse-type gastric cancer.

Genetic alteration of Rho GTPase-activating proteins (ARHGAP) and GTPase RhoA is a hallmark of diffuse-type gastric cancer and elucidating its biological significance is critical to comprehensively understanding this malignancy. Here, we report that gene fusions of ARHGAP6/ARHGAP26 are frequent genetic events in peritoneally-metastasized gastric and pancreatic cancer. From the malignant ascites of patients, we established gastric cancer cell lines that spontaneously gain hotspot RHOA mutations or four different ARHGAP6/ARHGAP26 fusions. These alterations critically downregulate RhoA-ROCK-MLC2 signaling, which elicits cell death. Omics and functional analyses revealed that the downstream signaling initiates actin stress fibers and reinforces intercellular junctions via several types of catenin. E-cadherin-centered homotypic adhesion followed by lysosomal membrane permeabilization is a pivotal mechanism in cell death. These findings support the tumor-suppressive nature of ARHGAP-RhoA signaling and might indicate a new avenue of drug discovery against this refractory cancer.

Clinical practice guideline for the treatment of malignant ascites: section summary in Clinical Practice Guideline for peritoneal dissemination (2021).

Patients with peritoneal dissemination (PD) caused by abdominal malignancies are often associated with massive ascites, which shows extremely dismal prognosis because of the discontinuation of systemic chemotherapy mostly due to poor performance status. Many treatment methods, such as simple drainage, peritoneovenous shunting (PVS) and cell-free and concentrated reinfusion therapy (CART), have been used for symptom relief. However, the clinical efficacies of these methods have not been fully investigated yet. Recently, we developed the Clinical Practice Guideline for PD caused by various malignancies according to "Minds Clinical Practice Guideline Development Guide 2017". In this guideline, we systematically reviewed information on clinical diagnosis and treatments for PD using PubMed databases (2000 - 2020), and clarified the degree of recommendation for clinical questions (CQ). The evidence level was divided into groups by study design and quality. The literature level and a body of evidence were evaluated in reference to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Based on the results of systematic review, the strength of the recommendations was evaluated at a consensus meeting of the Guideline Committee. This is the English synopsis of the part of treatment of malignant ascites in Clinical Practice Guideline for PD, 2021 in Japanese. The guidelines summarize the general aspect of the treatment of malignant ascites and statements with recommendation strengths, evidence levels, agreement rates and future perspective for four raised clinical questions.

Proteomic Analysis of Malignant Ascites From Patients With Pancreatic Ductal Adenocarcinoma.

BACKGROUND/AIM: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignant tumor. Research using an innovative research approach is needed to identify effective biomarkers or therapeutic targets for PDAC. We aimed to identify proteins related to the peritoneal dissemination of PDAC. MATERIALS AND METHODS: We performed proteomic analysis using ascites samples from patients with advanced PDAC and peritoneal dissemination and patients with liver cirrhosis (LC). Proteins specific to PDAC were identified in comparison to the findings for ascites from patients with LC as a control group. RESULTS: In total, 336 proteins were identified in ascites from patients with PDAC. We identified 18 specific proteins in ascites from patients with advanced PDAC. Among these proteins, CD13, lymphatic vessel endothelial hyaluronan receptor 1, ficolin-3, and V-set and immunoglobulin domain containing 4 were the most frequently detected. In addition, these 18 proteins could be classified into four categories: extracellular matrix, immunity, metabolism, and others. CONCLUSION: The identified proteins could be informative for developing treatment strategies for patients with PDAC and peritoneal dissemination.

Large-volume cell-free and concentrated ascites reinfusion therapy improves venous flow in patients with liver cirrhosis.

PURPOSE: Hemodynamic change after total paracentesis was investigated because it might lead to various complications. Although cell-free and concentrated ascites reinfusion therapy (CART) is safer and more effective than total paracentesis in theory, hemodynamic change after CART has been never reported. And previous studies did not mention hemodynamics of the venous system. METHODS: We investigated the hemodynamic change, including that of the venous system, before and after CART using color Doppler ultrasonography and fast Fourier transform analysis. Twenty-eight patients with tensive cirrhotic ascites underwent ultrasonography the day before and after total volume CART. The diameter and velocity of the main, right, and left portal vein; inferior vena cava (IVC); and right renal vein were measured using ultrasonography. RESULTS: A total of 11.8 ± 4.4 L of ascites (range 3.6-20.9 L) was filtered and concentrated to 0.85 ± 0.40 L (range 0.36-1.50 L). The diameter of the IVC increased from median 13.5 ± 5.4 mm (range 4-25 mm) to 18.5 ± 4.1 mm (range 7-29 mm) (p = 0.007). The diameter of the right segmental renal vein significantly increased after KM-CART [from 5.0 ± 1.0 (4-8) mm to 7.0 ± 2.0 (3-10) mm] (p = 0.011). Hemodynamic change of the portal venous system was not significant. The time to the next CART in patients with an IVC diameter ≥ 20 mm and < 20 mm was 86 days and 20.5 days (p = 0.035), respectively. CONCLUSION: Tensive ascites results in venous congestion in patients with cirrhotic ascites. CART improved venous flow, but it did not change the hemodynamics of the portal venous system.

Inflammation-driven senescence-associated secretory phenotype in cancer-associated fibroblasts enhances peritoneal dissemination.

In the tumor microenvironment, senescent non-malignant cells, including cancer-associated fibroblasts (CAFs), exhibit a secretory profile under stress conditions; this senescence-associated secretory phenotype (SASP) leads to cancer progression and chemoresistance. However, the role of senescent CAFs in metastatic lesions and the molecular mechanism of inflammation-related SASP induction are not well understood. We show that pro-inflammatory cytokine-driven EZH2 downregulation maintains the SASP by demethylating H3K27me3 marks in CAFs and enhances peritoneal tumor formation of gastric cancer (GC) through JAK/STAT3 signaling in a mouse model. A JAK/STAT3 inhibitor blocks the increase in GC cell viability induced by senescent CAFs and peritoneal tumor formation. Single-cell mass cytometry revealed that fibroblasts exist in the ascites of GC patients with peritoneal dissemination, and the fibroblast population shows p16 expression and SASP factors at high levels. These findings provide insights into the inflammation-related SASP maintenance by histone modification and the role of senescent CAFs in GC peritoneal dissemination.

Multi-omic profiling of peritoneal metastases in gastric cancer identifies molecular subtypes and therapeutic vulnerabilities.

Peritoneal metastasis, a hallmark of incurable advanced gastric cancer (GC), presently has no curative therapy and its molecular features have not been examined extensively. Here we present a comprehensive multi-omic analysis of malignant ascitic fluid samples and their corresponding tumor cell lines from 98 patients, including whole-genome sequencing, RNA sequencing, DNA methylation and enhancer landscape. We identify a higher frequency of receptor tyrosine kinase and mitogen-activated protein kinase pathway alterations compared to primary GC; moreover, approximately half of the gene alterations are potentially treatable with targeted therapy. Our analyses also stratify ascites-disseminated GC into two distinct molecular subtypes: one displaying active super enhancers (SEs) at the ELF3, KLF5 and EHF loci, and a second subtype bearing transforming growth factor-ß (TGF-ß) pathway activation through SMAD3 SE activation and high expression of transcriptional enhancer factor TEF-1 (TEAD1). In the TGF-ß subtype, inhibition of the TEAD pathway circumvents therapy resistance, suggesting a potential molecular-guided therapeutic strategy for this subtype of intractable GC.

Feasibility, efficacy, and safety of cell-free and concentrated ascites reinfusion therapy (KM-CART) for malignant ascites.

Efficacy for alleviating signs/symptoms of malignant ascites of a renovated CART (cell-free and concentrated ascites reinfusion therapy) system, called KM-CART, was evaluated. A total of 4781 KM-CART procedures were performed in 2109 patients. All patients were accepted unless hemodynamically unstable or consciousness impaired. The ascites were processed and drip-infused into the patient. There were no major complications or deaths. The mean drainage volume was 6.2 L (maximum: 27.7 L), patient symptoms (numerical scale system) were significantly alleviated (45.1 ± 19.0 reduced to 21.2 ± 14.2, P < .001), and patient leg circumference significantly decreased (33.3 ± 4.4 cm reduced to 30.5 ± 4.4 cm, P < .001) without exacerbation of renal function. Collected cancer cells could be utilized for immune therapy. KM-CART is capable of improving the "quality of best supportive care" and can be beneficial in conjunction with medication for alleviating malignant pain.

Efficacy of glutathione inhibitors for the treatment of ARID1A-deficient diffuse-type gastric cancers.

ARID1A, a subunit of the SWI/SNF chromatin remodeling complex, increases the intracellular levels of glutathione (GSH) by upregulating solute carrier family 7 member 11 (SLC7A11). Diffuse-type gastric cancer is an aggressive tumor that is frequently associated with ARID1A deficiency. Here, we investigated the efficacy of GSH inhibition for the treatment of diffuse-type gastric cancer with ARID1A deficiency using ARID1A-proficient or -deficient patient-derived cells (PDCs). ARID1A-deficient PDCs were selectively sensitive to the GSH inhibitor APR-246, the GCLC inhibitor buthionine sulfoximine, and the SLC7A11 inhibitor erastin. Expression of SLC7A11, which is required for incorporation of cystine, and the basal level of GSH were lower in ARID1A-deficient than in ARID1A-proficient PDCs. Treatment with APR-246 decreased intracellular GSH levels, leading to the excessive production of reactive oxygen species (ROS), and these phenotypes are suppressed by supply of cystine and GSH compensators. Taken together, vulnerability of ARID1A-deficient gastric cancer cells to GSH inhibition is caused by decreased GSH synthesis due to diminished SLC7A11 expression. The present results suggest that GSH inhibition is a promising strategy for the treatment of diffuse-type gastric cancers with ARID1A deficiency.

In-vitro proliferation assay with recycled ascitic cancer cells in malignant pleural mesothelioma: A case report.

BACKGROUND: We report the first case, to the best of our knowledge, of massive ascites due to recurrent malignant pleural mesothelioma that was controlled using KM-cell-free and concentrated ascites reinfusion therapy (KM-CART). The tumor cells derived via KM-CART were utilized secondarily in an in vitro cell growth assay using the collagen gel droplet-embedded culture drug sensitivity test (CD-DST) to investigate anticancer drug susceptibility. CASE SUMMARY: A 56-year-old man presented with recurrent malignant mesothelioma with massive ascites; more than 4000 mL of ascitic fluid was removed, filtered, and concentrated using KM-CART, and the cell-free ascitic fluid was reinfused into the patient to improve quality of life. Cancer cells isolated secondarily in an in vitro proliferation assay using CD-DST exhibited low sensitivity to pemetrexed and high sensitivity to gemcitabine. Treatment with gemcitabine maintained stable disease for 4 mo. CONCLUSION: The combination of KM-CART and CD-DST may be a promising treatment option for malignant ascites associated with malignant mesothelioma.

[Usefulness of Peripherally Inserted Central Venous Catheters for Cancer Patients in Palliative Care Settings].

Peripherally inserted central venous catheters(PICCs)are widely used given they have lower incidence of serious complications than central venous catheters. We evaluated the safety and usefulness of ultrasound-guided PICC placement for cancer patients in palliative care settings. We attempted to insert PICCs in 42 patients, and the insertion was successful in 40 (95.2%)patients. Complications occurred in 9(22.5%)patients, but none were severe. In 30 cases, PICCs were used for infusion and drug delivery until cancer death. The duration of catheterization was 25(1-126)days. Our results suggest that ultrasound-guided PICC represents a safe and usefultoolfor cancer patients in palliative care settings.

A Tumor-targeting Adenovirus with High Gene-transduction Efficiency for Primary Pancreatic Cancer and Ascites Cells.

BACKGROUND: Optimizing targeting strategies for vectors in order to enhance antitumor activity and secure patient safety is important for cancer gene therapy. We previously identified two pancreatic cancer-targeting ligands (PFWSGAV: PFW and SYENFSA: SYE) by screening an adenovirus library in vivo and in vitro, respectively. MATERIALS AND METHODS: To examine clinical usefulness, we assessed gene-transduction efficiency using surgically-resected pancreatic cancer specimens and ascites cells. RESULTS: For surgical specimens, vectors displaying PFW and SYE improved transduction efficiency by 4.4- and 4.3-fold, respectively. The SYE-displaying vector was >2-fold more efficient for all seven cases, whereas the PFW-displaying vector increased efficiency in two out of four cases. For ascites samples, both vectors increased gene-transduction efficiency of epithelial cell adhesion molecule (EpCAM)-positive ascites cells by >2-fold in two out of five cases. CONCLUSION: Both vectors enhanced adenovirus infectivity of pancreatic cancer cells and have potential for gene therapy of pancreatic cancer; therefore they should be further evaluated in clinical studies.

Analysis of glycero-lysophospholipids in gastric cancerous ascites.

Lysophosphatidic acid (LysoPA) has been proposed to be involved in the pathogenesis of various cancers. Moreover, glycero-lysophospholipids (glycero-LysoPLs) other than LysoPA are now emerging as novel lipid mediators. Therefore, we aimed to elucidate the possible involvement of glycero-LysoPLs in the pathogenesis of gastric cancer by measuring glycero-LysoPLs, autotaxin (ATX), and phosphatidylserine-specific phospholipase A1 (PS-PLA1) in ascites obtained from patients with gastric cancer and those with cirrhosis (as a control). We observed that after adjustments according to the albumin levels, the lysophosphatidylserine (LysoPS) and lysophosphatidylglycerol (LysoPG) levels were significantly higher, while the LysoPA and ATX levels were lower, in the ascites from patients with gastric cancer. We also found that multiple regression analyses revealed that ATX was selected as a significant explanatory factor for all the detectable LysoPA species only in the cirrhosis group and that a significant positive correlation was observed between LysoPS and PS-PLA1 only in the gastric cancer group. In conclusion, the LysoPA levels might be determined largely by LysoPC and LysoPI (possible precursors) and the PS-PLA1-mediated pathway might be involved in the production of LysoPS in gastric cancer. Glycero-LysoPLs other than LysoPA might also be involved in the pathogenesis of cancer directly or through being converted into LysoPA.

Overexpression of KIF11 in Gastric Cancer with Intestinal Mucin Phenotype.

OBJECTIVE: Gastric cancer (GC) is one of the most common human cancers. A useful method of gastric cancer stem cell (CSC) characterization is spheroid colony formation. Previously, we reported that KIF11 expression is >2-fold in spheroid-body-forming GC cells compared with parental cells. Here, we analyzed the expression and distribution of KIF11 in human GC by immunohistochemistry. METHODS: Expression of KIF11 in 165 GC cases was determined using immunohistochemistry. For mucin phenotypic expression analysis of GC, immunostaining of MUC5AC, MUC6, MUC2 and CD10 was evaluated. RNA interference was used to inhibit KIF11 expression in GC cell lines. RESULTS: In total, 119 of 165 GC cases (72%) were positive for KIF11. Expression of KIF11 was not associated with any clinicopathologic characteristics; however, it was observed frequently in GC exhibiting an intestinal phenotype. Both the number and size of spheres formed by MKN-74 cells were significantly reduced following transfection of KIF11-targeting siRNA compared with negative-control siRNA. Furthermore, levels of phosphorylated Erk1/2 were lower in KIF11 siRNA-transfected cells than with negative-control siRNA-transfected cells. CONCLUSION: These results indicate that KIF11 is involved in intestinal mucin phenotype GC.

[A New Treatment Strategy-Novel Cell-Free and Concentrated Ascites Reinfusion System(KM-CART)for Massive Malignant Ascites].

Massive ascites associated with cancerous peritonitis can result in severe respiratory discomfort and abdominal fullness. Additionally, it can significantly impair the activities of daily living of a patient, and relaxation is difficult to achieve, even with opioids. Frequent ascites drainage can cause rapid worsening of the patient's general condition, and a large amount of ascites can lead to discontinuation of anti-cancer treatment. Cell-free and concentrated ascites reinfusion therapy(CART)for refractory ascites was first covered by the insurance system in 1981. However, cancerous ascites includes many cellular components as well as mucus, and purification was a difficult process. Therefore, since the 1990s, CART disappeared from the field of cancer treatment. I have devised a Keisuke Matsusaki(KM)-CART system that has the ability to clean the filtration membrane. This system enables purification of massive cancerous ascites that may exceed 20 L. The general condition of the patients and their symptoms improve after use of KM-CART, making it possible to initiate or resume anti-cancer therapy. KM-CART helps remove unwanted components, such as cancer cells, cytokines, and vascular endothelial growth factors from the abdominal cavity through filtration of drained ascites. Therefore, the peritoneal environment can be improved, leading to enhancement of the efficacy of intraperitoneal chemotherapy. In addition, a large number of cancer cells and lymphocytes can be obtained with KM-CART, and it is possible to use these cells for customized cancer treatments, such as dendritic cell vaccine therapy, and to perform anti-cancer agent susceptibility testing. I believe that KM-CART is a good treatment approach for massive ascites associated with cancerous peritonitis.

Effective recovery of highly purified CD326(+) tumor cells from lavage fluid of patients treated with a novel cell-free and concentrated ascites reinfusion therapy (KM-CART).

For the production of tumor-specific vaccines, including dendritic cell (DC) vaccines, the tumor cells themselves are an ideal source. Floating tumor cells in the ascites fluid from patients with malignant ascites are a good candidate source, but it is not easy to obtain pure tumor cells from ascites because of various types of cell contamination as well as protein aggregates. We here report an effective method to recover pure tumor cells from malignant ascites. We used lavage fluid from 13 patients with malignant ascites who were treated with modified cell-free and concentrated ascites reinfusion therapy (KM-CART). Cellular components were separated from the lavage fluid by centrifugation, enzymatic digestion and hemolysis. Tumor cells were purified by depleting CD45(+) leukocytes with antibody-conjugated magnetic beads. The tumor cell lysate was extracted by freeze-and-thaw cycles. The mean obtained total cell number was 7.50 × 10(7) cells (range 4.40 × 10(6)-2.48 × 10(8) cells). From this fraction, 6.39 × 10(6) (range 3.23 × 10(5)-2.53 × 10(7)) CD45(-) cells were collected, and the tumor cell purity was over 80 % defined as CD45(-)CD326(+). A sufficient amount of tumor lysate, average  = 2416 µg (range 25-8743 µg), was extracted from CD45(-)CD326(+) tumor cells. We here established an effective method to produce highly purified tumor cells from KM-CART lavage fluid. The clinical feasibility of this simple preparation method for generating tumor lysate should be examined in clinical studies of DC vaccines.

Identification and Characterization of CXCR4-Positive Gastric Cancer Stem Cells.

Diffuse-type solid tumors are often composed of a high proportion of rarely proliferating (i.e., dormant) cancer cells, strongly indicating the involvement of cancer stem cells (CSCs) Although diffuse-type gastric cancer (GC) patients have a poor prognosis due to high-frequent development of peritoneal dissemination (PD), it is limited knowledge that the PD-associated CSCs and efficacy of CSC-targeting therapy in diffuse-type GC. In this study, we established highly metastatic GC cell lines by in vivo selection designed for the enrichment of PD-associated GC cells. By microarray analysis, we found C-X-C chemokine receptor type 4 (CXCR4) can be a novel marker for highly metastatic CSCs, since CXCR4-positive cells can grow anchorage-independently, initiate tumors in mice, be resistant to cytotoxic drug, and produce differentiated daughter cells. In clinical samples, these CXCR4-positive cells were found from not only late metastasis stage (accumulated ascites) but also earlier stage (peritoneal washings). Moreover, treatment with transforming growth factor-ß enhanced the anti-cancer effect of docetaxel via induction of cell differentiation/asymmetric cell division of the CXCR4-positive gastric CSCs even in a dormant state. Therefore, differentiation inducers hold promise for obtaining the maximum therapeutic outcome from currently available anti-cancer drugs through re-cycling of CSCs.

Endoscopic Resection is Infeasible for Early Gastric Cancers with Undifferentiated Components.

BACKGROUND/AIMS: Aim of this study is to find subgroup of early gastric cancer with lymph node metastasis for which successive further surgical operation is needed after endoscopic resection. METHODOLOGY: A total of 559 lesions of early gastric cancer, which had undergone curative gastrectomy, were enrolled in this study. We retrospectively investigated 10 clinicopathological factors predictive of lymph node metastasis by univariate and multivariate analysis. We showed the frequency of lymph node metastasis of subgroups in combination of independent factors selected by multivariate analysis. RESULTS: Lymph node metastases were detected in 57 lesions (10.2%). Univariate analysis revealed that lesion size > 30 mm, undifferentiated components, sm massive invasion, lymphatic invasion and venous invasion were factors significantly correlated with lymph node metastasis. By multivariate analysis, risk factors for lymph node metastasis were lesion size > 30 mm, undifferentiated components, sm massive invasion, and lymphatic invasion, with odds ratios of 2.17, 2.30, 5.88 and 8.24, respectively. In lesions with undifferentiated components, LNM were found in all subgroups. CONCLUSIONS: When we treat early gastric cancers contained undifferentiated components, even if they are predominantly differentiated-type intramucosal lesions, an additional surgical procedure should be considered or careful follow-up is required.

Novel cell-free and concentrated ascites reinfusion therapy (KM-CART) for refractory ascites associated with cancerous peritonitis: its effect and future perspectives.

BACKGROUND: We have actively carried out cell-free and concentrated ascites reinfusion therapy (CART) for refractory ascites. However, with conventional CART, the membrane becomes clogged after processing about 2 L of cancerous ascites fluid due to the fact that it is rich in cellular and mucous components; it is therefore difficult to process the entire volume of collected ascites. METHODS: We developed KM-CART which includes a membrane cleaning function, and applied it in 73 cases of cancerous ascites, after its basic functions had been evaluated in 11 cases of refractory cancerous ascites. RESULTS: On average, using KM-CART, 6.4 L (range 1.7-14.9 L) of ascites were filtrated and concentrated to 0.8 L (0.2-2.0 L) in 57 min (5-129 min); the membrane was cleaned an average of three times (range 0-10 times) and this enabled the processing of more ascites in a shorter period. In addition, the circuit and the handling were both markedly simple, and fever, which has been the most notable adverse effect with the conventional system, was not an issue. CONCLUSION: Since KM-CART was safe and is expected to improve the subjective symptoms and general condition of the patient, it is proposed that this novel system should actively be used not only for palliation but also as supplementary treatment for cancerous peritonitis.