Gastric cancer derived exosomes mediate the delivery of circRNA to promote angiogenesis by targeting miR-29a/VEGF axis in endothelial cells.

Accumulating evidence has been found that circular RNA (circRNA) plays a critical role in the initiation and development of various diseases by modulating gene expression in the cytoplasm. However, the role of circ_0044366 (termed circ29) in gastric cancer (GC) has yet to be elusive. We detected that exosomal circ29 was confirmed to be highly expressed in GC and can significantly impair the proliferation, migration, tube formation of HUVEC by exosomal communication. Interestingly, this effect could be blocked by the effect of miR-29a. In brief, we confirmed that circ29, as a sponge of miR-29a, plays a responsible role in the occurrence and development of GC by regulating the VEGF pathway. Therefore, it may be used as a potential target for the treatment of GC.

DJ-1 is involved in the multidrug resistance of SGC7901 gastric cancer cells through PTEN/PI3K/Akt/Nrf2 pathway.

Gastric cancer is a common malignancy worldwide. The occurrence of multidrug resistance (MDR) is the major obstacle for effective gastric cancer chemotherapy. In this study, the in-depth molecular mechanism of the DJ-1-induced MDR in SGC7901 gastric cancer cells was investigated. The results showed that DJ-1 expression level was higher in MDR variant SGC7901/VCR cells than that in its parental SGC7901 cells. Moreover, DJ-1 overexpression conferred the MDR phenotype to SGC7901 cells, while DJ-1 knockdown in SGC7901/VCR cells induced re-sensitization to adriamycin, vincristine, cisplatin, and 5-fluorouracil. These results suggested that DJ-1 mediated the development of MDR in SGC7901 gastric cancer cells. Importantly, further data revealed that the activation of PI3k/Akt and Nrf2 signaling pathway were required for the DJ-1-induced MDR phenotype in SGC7901 gastric cancer cells. Meanwhile, we found that PI3k/Akt pathway was activated probably through DJ-1 directly binding to and negatively regulating PTEN, consequently resulting in Nrf2 phosphorylation and activation, and thereby inducing Nrf2-dependent P-glycoprotein (P-gp) and Bcl-2 expressions in the DJ-1-mediated MDR of SGC7901 gastric cancer cells. Overall, these results revealed that activating PTEN/PI3K/Akt/Nrf2 pathway and subsequently upregulating P-gp and Bcl-2 expression could be a critical mechanism by which DJ-1 mediates the development of MDR in SGC7901 gastric cancer cells. The new findings may be helpful for understanding the mechanisms of MDR in gastric cancer cells, prompting its further investigation as a molecular target to overcome MDR.

N6-(2-hydroxyethyl)-Adenosine Induces Apoptosis via ER Stress and Autophagy of Gastric Carcinoma Cells In Vitro and In Vivo.

Gastric cancer is the most common malignant tumor of the digestive tract and is great challenge in clinical treatment. N6-(2-Hydroxyethyl)-adenosine (HEA), widely present in various fungi, is a natural adenosine derivative with many biological and pharmacological activities. Here, we assessed the antineoplastic effect of HEA on gastric carcinoma. HEA exerted cytotoxic effects against gastric carcinoma cells (SGC-7901 and AGS) in a dose and time-dependent manner. Additionally, we found that HEA induced reactive oxygen species production and mitochondrial membrane potential depolarization. Moreover, it could trigger caspase-dependent apoptosis, promoting intracellular Ca2+-related endoplasmic reticulum (ER) stress and autophagy. On the other hand, HEA could significantly inhibit the growth of transplanted tumors in nude mice and induce apoptosis of tumor tissues cells in vivo. In conclusion, HEA induced apoptosis of gastric carcinoma cells in vitro and in vivo, demonstrating that HEA is a potential chemotherapeutic agent for gastric carcinoma.

Exosomal miRNAs as circulating biomarkers for prediction of development of haematogenous metastasis after surgery for stage II/III gastric cancer.

Exosomes secreted by living cancer cells can regulate metastasis. Exosomal miRNAs can reflect pathological conditions of the original cancer cells. Therefore, we aim to identify exosomal miRNAs as circulating biomarkers for haematogenous metastasis of gastric cancer. Pre-treatment serum samples of eighty-nine patients with stage II/III gastric cancer were collected. Thirty-four of them developed haematogenous metastasis after surgery and the other fifty-five did not. Extraction of exosomes was validated by western blot, transmission electron microscopy and nanoparticle tracking analysis. MiRNA qPCR array was performed in three matched pairs of samples. Internal control was selected from PCR array and validated in the remaining samples. Expressions of exosomal miRNAs were evaluated in the remaining samples by RT-qPCR, as well as in gastric cancer tissue samples and cell culture medium. Expression levels of exosomal miRNAs were analysed with clinical characteristics. The results indicated thirteen up-regulated and six down-regulated miRNAs were found after normalization. MiR-379-5p and miR-410-3p were significantly up-regulated in metastatic patients (P < .01). Higher expression of exosomal miR-379-5p or miR-410-3p showed shorter progression-free survival of the patients (P < .05). It was also found that miR-379-5p and miR-410-3p were down-regulated in gastric cancer tissue samples, while they were significantly up-regulated in gastric cancer cell culture medium compared with cancer cells. In conclusion, exosomal miRNAs are promising circulating biomarkers for prediction of development of haematogenous metastasis after surgery for stage II/III gastric cancer.

Complete histopathologic examination of risk reduction gastrectomy specimens for CDH1 germline mutation: Is it warranted in routine clinical practice?

AIMS: CDH1 germline mutation is associated with high penetrance of hereditary diffuse gastric cancer (HDGC). Due to the lack of endoscopically identifiable lesions, routine surveillance is ineffective in the early detection of gastric cancer, and risk-reduction gastrectomy is often recommended. Many academic pathology departments elect to submit the entire gastrectomy specimen for histological examination, which is associated with significantly increased cost, technical and professional time, and turnaround time. METHODS: We present our experience with 5 completely submitted and 2 representatively submitted prophylactic total gastrectomy cases in HDGC patients. RESULTS: Multifocal intramucosal signet ring cell carcinoma was identified in all cases except one, in which only in situ carcinoma was identified. The tumoral foci (2 to 35 per case; average 14.4) were concentrated in proximal stomach. No submucosal invasion or nodal metastases was seen in any case. The final stage was either stage 0 (pTisN0cM0) or stage 1a (pT1aN0cM0). CONCLUSIONS: Our findings are in line with that reported in the literature. Considering that deeply invasive carcinoma is very rare in this situation, and no further treatment is indicated for the vast majority of those patients, complete submission and pathologic examination of the entire stomach provides little additional value for routine clinical management. We propose a two-step approach with targeted submission of the proximal stomach, and subsequent entire submission of the remaining stomach if no intramucosal carcinoma is identified during the initial targeted examination.

Exosome-mediated transfer of CLIC1 contributes to the vincristine-resistance in gastric cancer.

Our previous study shows that high Chloride intracellular channel 1 (CLIC1) expression can efficiently enhance invasion and migration of gastric cancer (GC) cells in vitro. Growing evidences have found that exosomes are involved in chemotherapy resistance in several cancers including GC. We aimed to evaluate the effect of the exosome-mediated transfer of CLIC1 in the vincristine-resistance of GC. The effect of exosome-mediated transfer of CLIC1 on the development of resistance to vincristine in GC cell line SGC-7901 and the potential underlying mechanisms were investigated by Cell Counting Kit-8 (CCK8), RT-PCR, and Western blotting. Exosomes were isolated from cell supernatants by differential ultracentrifugation. Comparing with SGC-7901, the expression level of CLIC1 is higher in vincristine­resistant cell line SGC-7901/VCR (P < 0.05). After silencing the expression of CLIC1 by RNA interference, the half inhibition concentration (IC50) to vincristine decreased significantly in SGC-7901/VCR, and the expression of CLIC1 decreased significantly in exosomes from SGC-7901/VCR. After 48 h co-culturing with exosomes from SGC-7901/VCR, the IC50 to vincristine in SGC-7901 increased significantly, and the expression of CLIC1, P-gp, and Bcl-2 were significantly up-regulated. CLIC1 was closely associated with the resistance to vincristine in GC, and exosome-mediated transfer of CLIC1 could induce the development of resistance to vincristine in vitro. The possible mechanism was related to up-regulated P-gp and Bcl-2. However, in vivo study was needed to confirm the results in future.

A Novel Anti-HER2 Antibody-Drug Conjugate XMT-1522 for HER2-Positive Breast and Gastric Cancers Resistant to Trastuzumab Emtansine.

Most patients with HER2-positive breast or gastric cancer exhibit primary or acquired resistance to trastuzumab emtansine (T-DM1), and such patients may have limited therapeutic options. XMT-1522 is a novel anti-HER2 antibody-drug conjugate. We compared XMT-1522 to T-DM1 in preclinical models. The effects of XMT-1522 and T-DM1 on cell survival and apoptosis were compared in six HER2-positive breast cancer or gastric cancer cell lines, of which three lines were T-DM1-sensitive (N-87, OE-19, JIMT-1) and three T-DM1-resistant (RN-87, ROE-19, SNU-216). We compared these agents also in the HER2-negative breast cancer cell line MCF-7, and in mouse RN-87 and JIMT-1 xenograft models. Cell survival was assessed using the AlamarBlue method and apoptosis with the Caspase-Glo 3/7 method. XMT-1522 inhibited the growth of all six HER2-positive cell lines. The proportions of cells that survived XMT-1522 treatment were smaller as compared with T-DM1, particularly in the T-DM1-resistant cell lines. XMT-1522 induced more cell apoptosis compared with T-DM1. While RN-87 and JIMT-1 xenograft tumors progressed on T-DM1 treatment, all tumors responded to XMT-1522, and all but one tumor disappeared during the XMT-1522 treatment. XMT-1522 had a strong antitumor effect on RN-87 and JIMT-1 xenografts that progressed on T-DM1. We conclude that XMT-1522 was effective in HER2-positive breast cancer and gastric cancer cell lines resistant to T-DM1, and in xenograft models resistant to T-DM1. The results support the testing of XMT-1522 in clinical trials in patients with HER2-positive cancer.

Huachansu Capsule inhibits the proliferation of human gastric cancer cells via Akt/mTOR pathway.

BACKGROUND: For decades, the traditional Chinese medicine preparation, Huachansu Capsule (HCS), has been applied to a variety of solid tumors and leukemias with significant curative effects. More importantly, HCS has few side effects on cardiovascular and gastrointestinal functions in patients. However, the potential mechanism of the anti-tumor activity of HCS has not been fully revealed. The current study investigated the in vivo and in vitro effects of HCS on the proliferation and apoptosis of human gastric cancer (GC) cells and explored the underlying mechanism. MATERIALS AND METHODS: HCS was first diluted to varying concentrations followed by the treatment to MGC-803 and BGC-823 GC cells. Cell proliferation was evaluated by Cell Counting Kit-8 assay. Cell invasion and migration were assessed using Transwell membrane chambers. Apoptosis and cell cycle arrest in GC cells induced by HCS were detected by flow cytometry. Western blotting assays were used to measure the influence of HCS on apoptosis-related proteins, including B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and Cleaved-Caspase-3. Additionally, mammalian target of rapamycin (mTOR) signaling pathway-related proteins such as phosphorylated (p)-Akt, p-mTOR and p-4E-BP1 were detected. Transmission electron microscopy was used to observe the microstructure of apoptotic cells. An animal imaging technique was used to analyze the influence of HCS on the growth of GC cells in vivo and immunohistochemistry assays were performed to investigate the signal transduction pathways influenced by HCS. RESULTS: HCS significantly inhibited the proliferation, invasion and migration of MGC-803 and BGC-823 GC cells. It also induced cell cycle arrest at the G2/M phase and increased the cell apoptotic rate. Additionally, the HCS treatment downregulated the protein levels of Bcl-2, but upregulated the protein expression of Bax and cleaved-caspase 3. Furthermore, HCS downregulated the levels of p-Akt, p-mTOR and p-4E-BP1, suggesting that HCS inhibited tumor growth of GC via suppressing the Akt/mTOR pathway. CONCLUSION: This study indicated that HCS has significant anti-proliferative and apoptotic effects both in vitro and in vivo, and that HCS can inhibit tumor growth of GC via suppressing the Akt/mTOR pathway and induce apoptosis through the intrinsic pathway. Our study provides a scientific basis for the clinical application of HCS.

CD44s Assembles Hyaluronan Coat on Filopodia and Extracellular Vesicles and Induces Tumorigenicity of MKN74 Gastric Carcinoma Cells.

CD44 is a multifunctional adhesion molecule typically upregulated in malignant, inflamed and injured tissues. Due to its ability to bind multiple ligands present in the tumor microenvironment, it promotes multiple cellular functions related to tumorigenesis. Recent data has shown that CD44 and its principal ligand hyaluronan (HA) are carried by extracellular vesicles (EV) derived from stem and tumor cells, but the role of CD44 in EV shedding has not been studied so far. To answer this question, we utilized CD44-negative human gastric carcinoma cell line MKN74 manipulated to stably express CD44 standard form (CD44s). The effect of CD44s expression on HA metabolism, EV secretion, morphology and growth of these cells was studied. Interestingly, HAS2 and HYAL2 expression levels were significantly upregulated in CD44s-expressing cells. Cell-associated HA levels were significantly increased, while HA levels in the culture medium of CD44s-positive cells was lower compared to CD44s-negative MOCK cells. CD44s expression had no significant effect on the proliferation capacity of cells, but cells showed diminished contact inhibition. Superresolution imaging revealed that CD44s and HA were accumulated on filopodia and EVs secreted from CD44s-positive cells, but no differences in total numbers of secreted EV between CD44s-negative and -positive cells was detected. In 3D cultures, CD44s-expressing cells had an enhanced invasion capacity in BME gel and increased spheroidal growth when cultured in collagen I gel. No significant differences in mitotic activity, tumor size or morphology were detected in CAM assays. However, a significant increase in HA staining coverage was detected in CD44s-positive tumors. Interestingly, CD44s-positive EVs embedded in HA-rich matrix were detected in the stromal areas of tumors. The results indicate that CD44s expression significantly increases the HA binding capacity of gastric cancer cells, while the secreted HA is downregulated. CD44s is also carried by EVs secreted by CD44s-expressing cells. These findings highlight the potential usefulness of CD44s and its ligands as multipurpose EV biomarkers, because they are upregulated in inflammatory, injured, and cancer cells and accumulate on the surface of EVs secreted in these situations.

Analysis of Extracellular Vesicles in Gastric Juice from Gastric Cancer Patients.

Extracellular vesicles (EVs) are secretory membrane vesicles containing lipids, proteins, and nucleic acids; they function in intercellular transport by delivering their components to recipient cells. EVs are observed in various body fluids, i.e., blood, saliva, urine, amniotic fluid, and ascites. EVs secreted from cancer cells play important roles in the formation of their environment, including fibrosis, angiogenesis, evasion of immune surveillance, and even metastasis. However, EVs in gastric juice (GJ-EVs) have been largely unexplored. In this study, we sought to clarify the existence of GJ-EVs derived from gastric cancer patients. GJ-EVs were isolated by the ultracentrifuge method combined with our own preprocessing from gastric cancer (GC) patients. We verified GJ-EVs by morphological experiments, i.e., nanoparticle tracking system analysis and electron microscopy. In addition, protein and microRNA markers of EVs were examined by Western blotting analysis, Bioanalyzer, or quantitative reverse transcription polymerase chain reaction. GJ-EVs were found to promote the proliferation of normal fibroblast cells. Our findings suggest that isolates from the GJ of GC patients contain EVs and imply that GJ-EVs partially affect their microenvironments and that analysis using GJ-EVs from GC patients will help to clarify the pathophysiology of GC.

Bufalin induces protective autophagy by Cbl-b regulating mTOR and ERK signaling pathways in gastric cancer cells.

Bufalin, a natural small-molecule compound derived from the traditional Chinese medicine Chan su, has shown promising anti-cancer effects against a broad variety of cancer cells through different mechanisms. It has been reported to induce autophagy in gastric cancer cells. However, the molecular mechanism involved is not fully elucidated. In the present study, we aimed to investigate the molecular mechanism by which bufalin induce autophagy in human gastric cancer cells. We found that bufalin induced apoptosis and autophagy in gastric cancer cells, and autophagy prevented human gastric cancer cells from undergoing apoptosis. Bufalin treatment changed the expression of autophagy-related proteins. Moreover, phosphorylated Akt, mTOR, and p70S6K were all significantly decreased, while phosphorylated ERK1/2 was increased by bufalin. Pretreatment of MGC803 cells with the ERK1/2-specific inhibitor PD98059 led to the down-regulation of LC3 II. Further study showed that Cbl-b positively regulated autophagy by suppressing mTOR and enhancing ERK1/2 activation. Therefore, our data provide evidence that bufalin induces autophagy in MGC803 cells via both Akt/mTOR/p70S6K and ERK signaling pathways, and Cbl-b-mediated suppression of mTOR and activation of ERK1/2 might play an important role.

Jinlong Capsule (JLC) inhibits proliferation and induces apoptosis in human gastric cancer cells in vivo and in vitro.

BACKGROUND: As a representative traditional Chinese medicine made by modern pharmaceutical technology, Jinlong Capsule (JLC) has been used for several decades to treat liver cancer with significantly improved clinical outcomes as adjuvant therapy. JLC consists of three medicinal animals including freshly prepared Bungarus, Agkistrodon and Gecko. The active components were extracted by the process of modern cryogenic and biochemical separation from raw animals. However, the specific molecular mechanisms underlying the antitumor activities of JLC were not fully investigated. In the current study, experiments were carried out to examine the effect of JLC on anti-proliferative, pro-apoptotic activities of human gastric cancer (GC) cell lines in vivo and in vitro. METHODS: MTT assay was used to observe the viability of MGC-803 and BGC-823 cells treated with JLC. Apoptosis and cell cycle distribution of MGC-803 and BGC-823 cells induced by JLC were analyzed by flow cytometry. Western blot assay was used to detect the effect of JLC on apoptosis-related proteins, including Bax, Bcl-2, survivin and caspase-3. Transmission electron microscopy (TEM) was used to evaluate the microstructure of apoptotic GC cells. Tumor growth in vivo was monitored using live-imaging system. Immunohistochemical staining (IHC) was used to examine the expression of apoptosis-related proteins in tumor tissues. RESULTS: Our data indicated that JLC inhibited proliferation and induced apoptosis of MGC-803 and BGC-823 cells in a concentration-dependent manner. JLC significantly inhibited tumor growth in nude mice. Both in vivo and in vitro studies showed that JLC could downregulate the expression of Bcl-2 and survivin, whereas upregulate the levels of bax and caspase-3. JLC had significant antitumor effects in human GC through cell cycle arresting. Besides, JLC altered the microstructure of GC cells. CONCLUSION: These findings demonstrate that JLC can be considered as a promising candidate in GC treatment.

Lymph nodes around the posterior gastric artery: their existence, frequency, and clinical implications.

PURPOSE: The lymphatic flow along the posterior gastric artery (PGA) is considered of possible clinical importance in terms of lymphatic metastasis; however, little is known about the lymph nodes (LNs) around this artery. The purpose of this study was to establish if LNs exist around the PGA and to evaluate their clinical implications. METHODS: We examined the tissues surrounding the PGA from 21 cadavers to search for LNs. We also investigated the patterns of lymphatic metastases in patients who underwent surgery for gastric neoplasms at our institute to detect their presence along the PGA. RESULTS: The PGA was identified in 11 cadavers, and LNs around the PGA were detected microscopically in 2 of these. Lymphatic metastasis directly to the LNs at the splenic artery without any metastases was regarded as skip metastasis along the PGA. Skip metastasis was found in two of ten patients who underwent surgery for remnant gastric cancer. CONCLUSIONS: The existence of LNs around the PGA was confirmed, and based on our findings, lymphatic metastasis through the PGA is possible in patients with remnant gastric cancer.

Gastric adenocarcinoma expressing human epidermal growth factor receptor in South Asian population.

BACKGROUND/AIM: Gastric cancer is the third leading cause of cancer mortality worldwide. Human epidermal growth factor (Her-2/neu) has shown strong therapeutic implication in breast cancer. Although the prevalence of Her-2/neu over-expression in gastric cancer has been reported across the world, it is still unknown from South Asia. The aim of this study is to evaluate Her-2/neu expression in gastric adenocarcinomas and to correlate with various clinicopathological variables. PATIENTS AND METHODS: A total of 95 consecutive patients undergoing endoscopic biopsy or gastrectomy were recruited in this study. Clinicopathological parameters of all patients were recorded and hematoxylin and eosin (H and E) staining was performed. Over-expression of Her-2/neu was investigated by immunohistochemistry using α-Her-2 antibody. To quantify Her-2/neu over-expression, the Hofmann validation scoring system was used and further its association was seen with age, gender, histopathological type, grade, and stage of the tumor. Data were entered and analyzed using SPSS version 21. A P value of <0.05 was considered as significant. RESULTS: Overall, 21 (22.1%) cases were positive for Her-2/neu overexpression from the total of 95 gastric adenocarcinomas. Her-2/neu was significantly expressed in low-grade gastric cancer (grade I = 50%, grade II = 34.5%, grade III = 14.5%; P = 0.030). Although there was insignificant difference between Her-2/neu over expression and other variables, Her-2/neu score 3+ was predominantly seen in females, age >60 years, Laurens intestinal type, and IIIC stage tumors. CONCLUSION: Her-2/neu is over-expressed in a limited group of gastric cancer patients in our population and indicates a significant strong association with low grades of gastric cancer.

Curcumin regulates proliferation, autophagy, and apoptosis in gastric cancer cells by affecting PI3K and P53 signaling.

In this study, we aimed to investigate the effects of curcumin on cell activities of gastric cancer (GC), and the connection between curcumin and P53, as well as, PI3K signaling. This study was conducted with two cell lines SGC-7901 and BGC-823, both were exposed to curcumin at the concentrations of 0, 10, 20, and 40 µm. MTT assay, flow cytometry (FCM) assay, transmission electron microscopy (TEM) were used to study the underlying mechanisms of curcumin in respective of proliferation, apoptosis, and autophagy. Western blot assay was also employed to detect impacts of curcumin on tophosphatidylinositol-3 kinase (PI3K) and P53 signaling pathways-related proteins. MTT assay displayed that curcumin inhibited GC cell proliferation. FCM results indicated that curcumin induced the apoptosis of GC cells. TEM revealed that curcumin induced autophagy in GC cells. Western blot results showed that curcumin activated P53 signaling pathway and inhibited PI3K signaling pathway. Curcumin may inhibit proliferation and induce the autophagy and apoptosis in GC cells. Additionally, curcumin activated the P53 signaling pathway by up-regulating P53 and P21, which also inhibited PI3K pathway through down-regulating PI3K, p-Akt, and p-mTOR.

Significance of Cholinergic and Peptidergic Nerves in Stress-Induced Ulcer and MALT Lymphoma Formation.

Backgound: The role of enteric nerves has previously been demonstrated in the formation of several gastric diseases. In the present review, the significance of the cholinergic nerves in stress-induced ulcer formation as well as the importance of substance P in the formation of gastric MALT lymphoma is discussed. METHODS: The stress-induced ulcer was induced by the plaster bandage methods in rats. The gastric MALT lymphoma was formed by the peroral infection of gastric mucosal homogenate of the infected mouse in C57BL/6 mice. For the stress-induced ulcer, the distribution of the cholinergic nerves and muscarinic acetylcholine receptors was investigated by acetylcholinesterase histochemistry and autoradiography of water soluble compounds using 3H-quinuclidinyl benzilate was performed. To the MALT lymphoma study, the distribution of the substance P and effect of substance P antagonist, spantide II, was investigated by immunohistochemical studies. RESULTS: The stress induced ulcer formation was shown to be related to the hyperactivity of the cholinergic nerves. The gastric MALT lymphoma was shown to be related to the increased localization of substance P. CONCLUSION: Stress-induced ulceration as a model of hyperactivity of the cholinergic nerves was proved to be a useful approach, while substance P and its role in MALT lymphoma formation may serve as a tool to clarify the neuroimmune modulation of chronic infectious diseases.

Mast Cell Interaction with Neutrophils in Human Gastric Carcinomas: Ultrastructural Observations.

Aim. The role of mast cells in cell-cell immune interactions has received increasing attention, although their functional interaction with neutrophils still remains to be clarified in tumors. The aim of the present study was to investigate the association between mast cells and neutrophils in a series of gastric carcinomas (GC). Patients and Methods. 52 surgically resected GC specimens were routinely processed for both light and electron microscopy. Only cases showing both mast cells and neutrophils in the tumor stroma were considered in the analysis. Results. Only 9 GC (M : F = 5 : 4; age range: 50-82 years) showed both mast cells and neutrophils in the tumor stroma. At ultrathin sections, we identified heterotypic aggregation and intermingling of mast cells and neutrophils. Mast cells had mature phenotype and showed full complement of granules with homogeneous, scroll, particle, and mixed pattern. In addition, we found normal-appearing or early apoptosis showing neutrophils. Conclusion. Our histological findings showed the likely interaction between mast cells and neutrophils in GC. We hypothesize that the granular content of mast cells may be released in small quantity through a mechanism called "kiss-and-run fusion," which is alternative to well-known massive anaphylactic or piecemeal degranulation.

Cerium oxide nanoparticles inhibit the migration and proliferation of gastric cancer by increasing DHX15 expression.

Gastric cancer is one of the leading causes of tumor-related deaths in the world. Current treatment options do not satisfy doctors and patients, and new therapies are therefore needed. Cerium oxide nanoparticles (CNPs) have been studied as a potential therapeutic approach for treating many diseases. However, their effects on human gastric cancer are currently unknown. Therefore, in this study, we aimed to characterize the effects of CNPs on human gastric cancer cell lines (MKN28 and BGC823). Gastric cancer cells were cocultured with different concentrations of CNPs, and proliferation and migration were measured both in vitro and in vivo. We found that CNPs inhibited the migration of gastric cancer cells when applied at different concentrations, but only a relatively high concentration (10 µg/mL) of CNPs suppressed proliferation. Furthermore, we found that CNPs increased the expression of DHX15 and its downstream signaling pathways. We therefore provide evidence showing that CNPs may be a promising approach to suppress malignant activity of gastric cancer by increasing the expression of DHX15.

Pancreatic-type Acinar Cell Carcinoma of the Stomach Included in Multiple Primary Carcinomas.

BACKGROUND/AIM: Pancreatic-type acinar cell carcinoma (ACC) in the stomach is extraordinarily rare. We pathologically examined two cases with multiple primary carcinomas, including gastric tumors. PATIENTS AND METHODS: Gastric cancer specimens were examined by immunostaining and electron microscopy. RESULTS: Both cases had cancer cells with acinar patterns, resembling pancreatic ACC. The cancer cells in the first case were positive for exocrine markers, including chymotrypsin, lipase and alpha-1 antichymotrypsin (ACT), as well as neuroendocrine markers, including chromogranin A and synaptophysin. The cancer cells in the second case were positive for chymotrypsin and alpha-1 ACT, while being slightly positive for chromogranin A and synaptophysin. Ultrastructurally, cancer cells contained zymogen granules in both cases. The final diagnosis was pancreatic mixed acinar-neuroendocrine carcinoma and pure pancreatic ACC, respectively. CONCLUSION: We confirmed two cases with gastric pancreatic-type ACC included in multiple primary carcinomas. This type of double cancer has not been reported previously.