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Background: Data on the long-term oncological outcomes of patients who undergo conversion surgery (CS) in gastric cancer (GC) patients with peritoneal metastasis (PM) are limited. Methods: GC patients with PM who received intraperitoneal (ip) and systemic chemotherapy between April 2015 and January 2021 were enrolled. Multivariate analysis was performed to identify risk factors associated with survival. Clinicopathological and survival outcomes were compared between those with CS and those without CS (NCS). The paclitaxel (PTX) plus tegafur–gimeracil–oteracil potassium capsules (S-1) (PS) + ip PTX and oxaliplatin plus S-1 (SOX) + ip PTX groups were matched in a 1:1 ratio using propensity score matching. Oncological and survival data were collected and analyzed. Results: A total of 540 patients who received ip chemotherapy via subcutaneous port and systemic chemotherapy were analyzed and 268 patients were enrolled, including 113 who underwent CS and 155 who did not. Overall survival (OS) were 27.0 months and 11.8 months in the CS and NCS groups (P < 0.0001), respectively. R0 resection was an independent prognostic factor for patients who underwent CS. The OS of patients with or without ovariectomy was 21.3 or 12.0 months (P < 0.0001). No difference of clinicopathological and survival outcomes was found between the PS + ip PTX and SOX + ip PTX groups. Conclusion: Conversion therapy is safe and adverse events were manageable. CS improves the survival of GC patients with PM after ip and systemic chemotherapy. R0 is an important prognostic factor. Furthermore, outcomes are comparable between the PS + ip PTX and SOX + ip PTX groups. [ABSTRACT FROM AUTHOR]

Background: The prognosis of advanced gastric cancer (GC) invading the gastric serosa remains poor, mainly owing to high incidence of peritoneal recurrence. Patients with peritoneal metastases are often treated with neoadjuvant intraperitoneal and systemic chemotherapies (NIPS). Good responders to NIPS often undergo conversion gastrectomy. This study aims to explore biomarkers predicting the occurrence of peritoneal metastasis (PM) and evaluating the efficacy of NIPS in GC patients. Methods: We collected six peritoneal lavage (PL) samples from two patients with PM, two without PM, and two with diminished PM after NIPS via intraperitoneal access ports. We equally isolated microRNAs from exosomes derived from PL samples for deep sequencing. Two microRNAs (hsa-let-7g-3p and hsa-miR-10395-3p) were identified, and their expression levels were examined in PL samples of 99 GC patients using qRT-PCR. Moreover, we performed in vivo and in vitro functional assays to investigate effects of these microRNAs on metastasis and chemoresistance of GC cells. Results: Exosomal microRNA expression profiling of six PL samples indicated that the microRNA signature in exosomes of PLs from patients with diminished PM was similar to that from patients without PM. Expression levels of hsa-let-7g-3p and hsa-miR-10395-3p were associated with PM. In vivo and in vitro functional assays confirmed that hsa-let-7g-3p and hsa-miR-10395-3p are involved in GC metastasis and chemoresistance. Conclusion: PL-derived exosomes in GC contain large amounts of microRNAs related to PM. Moreover, hsa-let-7g-3p and hsa-miR-10395-3p could be used as biomarkers predicting PM and NIPS efficacy and are involved in GC metastasis and chemoresistance. [ABSTRACT FROM AUTHOR]

Purpose: To determine the maximum tolerated dose (MTD) and recommended dose (RD) of modified FLOT regimen (fluorouracil plus leucovorin, oxaliplatin and docetaxel) for treating Chinese patients with metastatic adenocarcinoma of stomach.Methods: Chinese patients with untreated advanced or metastatic stomach adenocarcinoma were enrolled. Docetaxel (D), oxaliplatin (O) and leucovorin were administrated intravenously on day 1. Fluorouracil (F) was administrated continuous intravenously on day 1 for 48 h. The treatment was repeated every 2 weeks. The start doses of docetaxel and oxaliplatin were 40 mg/m2 and 65 mg/m2, respectively. Dose escalation followed a 3 + 3 design. Total 6 dose levels were set to determine the MTD and RD. Fluorouracil and leucovorin were given as fix doses at 2200 mg/m2 and 200 mg/m2, respectively. Adverse events that occurred in the first 2 cycles were recorded to determine dose-limiting toxicity (DLT). The primary endpoints were MTD and RD determination.Results: A total of 18 patients were treated in 5 dose levels. DTL occurred in one patient of level 4 (grade 3 hypophosphatemia). Other 3 patients were enrolled in level 4 and no DLTs were observed. In level 5, 2 patients suffered grade 4 neutropenia after first cycle of treatment and were defined as DLTs. Therefore, level 5 (D/O/F: 50/75/2200 mg/m2) was defined as MTD and level 4 (D/O/F: 45/75/2200 mg/m2) was defined as RD. Common adverse events in first two cycles were nausea, anorexia, leukopenia, neutropenia and anemia. For 16 patients assessable for tumor response, 7 patients had partial response (43.7%) and 5 experienced stable disease. Disease control rate were 75% (12/16). Two patients underwent conversion operation after 6 cycles of treatment. One pathological complete response (case in level 3) and one pathological partial response (case in level 2) were observed. Median progression-free survival was 4.4 months (95% CI 2.9-5.9 months) in 14 patients.Conclusions: The RD of modified FLOT regimen in Chinese patients with advanced gastric cancer was docetaxel 45 mg/m2, oxaliplatin 75 mg/m2, leucovorin 200 mg/m2 and fluorouracil 2200 mg/m2 on day 1 of every 14-day cycle. Its efficacy will be assessed by further phase II study. [ABSTRACT FROM AUTHOR]

Background/aim: Epithelial-mesenchymal transition (EMT) plays a role in cancer progression. Previous studies have suggested that discoidin domain receptor 2 (DDR2) is related to tumor progression and EMT. However, the role of DDR2 in regulating gastric cancer (GC) metastasis and in EMT has not been elucidated. In this study, we aimed to determine DDR2 expression and its clinical relation in GC and to investigate the effects of DDR2 on EMT and its underlying mechanisms.Methods: DDR2 expression and the relation to patients' clinicopathological features were assayed by Western blot or immunohistochemical staining. The effects of DDR2 overexpression were investigated using in vivo tumorigenicity and xenograft models. The effects of DDR2 on EMT marker expression were assayed by Western blot and immunofluorescence. The possible role of the mTORC pathway in these processes was explored.Results: DDR2 showed high expression in GC tissues and cells. DDR2 expression was negatively correlated with E-cadherin expression and positively correlated with N-cadherin and vimentin expression. High DDR2 expression is correlated with unfavorable pathoclinical features such as multiple tumor locations and intestinal-type GC. In xenograft models, DDR2 overexpression promoted tumor formation. Furthermore, DDR2 expression impacted on the invasion and motility of GC cells, accompanied by changes in EMT marker expression. Finally, our results revealed that DDR2 facilitates GC cell invasion and EMT through mTORC2 activation and AKT phosphorylation.Conclusion: DDR2 is upregulated and correlated with unfavorable clinical features of GC patients. DDR2 promotes tumor formation and invasion through facilitating EMT process via mTORC2 activation and AKT phosphorylation. [ABSTRACT FROM AUTHOR]

The prolyl isomerase Pin1, which isomerizes the p-Ser/Thr-Pro peptide bonds and effects conformational and functional changes of the bound proteins, has been identified as a regulator of phosphorylation signaling in several diseases including cancer. The aim of this study is to determine the expression status of Pin1 in gastric cancer, its relationship between clinicopathologic features and patients' outcome. The mRNA levels of Pin1 in human normal and gastric cancer tissues were analyzed using the datasets from the publicly available Oncomine database (). Pin1 protein levels in human gastric cancer cells and tissues were analyzed by Western blot and immunohistochemistry staining, respectively. The Pin1 protein expression levels and its clinicopathologic correlations were investigated using tumor tissue microarray including 182 cases of human gastric cancer samples with survival information. Pin1 mRNA expression was found to be overexpressed in gastric cancer by using several datasets of Oncomine database analyzing. Pin1 protein expression is higher in 10 gastric cancer cell lines than that in normal gastric epithelial cell line GES-1. Pin1 positive expression was observed in 109 of 182 (59.9 %) gastric cancer samples and in 55 of 182 (30.2 %) normal gastric tissues ( P < 0.001). Correlation analysis showed that high expression of Pin1 was significantly associated with pT ( P = 0.017), pN ( P = 0.043), TNM staging ( P = 0.027), Lauren's classification ( P < 0.001), as well as shorter overall survival in gastric cancer patients (29 mos vs. 47 mos. P = 0.048). Moreover, Pin1 expression, pT, and differentiation were independent prognostic factors of gastric cancer in Cox regression analysis. Pin1 is overexpressed in gastric cancer and correlates with clinicopathologic features, which might predict poor prognosis of gastric cancer patients. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study is to investigate whether Dasatinib, a Src inhibitor, has the synergistic effect with oxaliplatin in treating gastric cancer cells. Methods: The baseline levels of total Src and p-Src in 10 human gastric cancer cell lines and gastric mucosa epithelial cell line GES-1 were detected by Western blot (WB). The changes of Src and p-Src expression after oxaliplatin exposure were evaluated by WB. The combination indices and clonogenic assay were used to evaluate the synergistic effects of dasatinib with oxaliplatin on cell growth and proliferation in vitro. Gastric cancer xenografts in nude mice were established and treated by oxaliplatin with or without dasatinib. The tumor growth curves were calculated and the impacts of different treatment on the tumor proliferation and src protein expression in gastric cancer xenografts were determined by immunohistochemistry staining and WB. Results: The different levels of Src expression in gastric cancer cells were related with their different sensitivity to oxaliplatin. The expression of p-Src, but not total Src, was elevated after oxaliplatin exposure both in vitro and in vivo. Dasatinib could dramatically inhibit p-Src expression, and combination indices demonstrated that dasatinib and oxaliplatin were synergistic in inhibiting gastric cancer cell growth. Dasatinib plus oxaliplatin were more effective in inhibiting clone formation than oxaliplatin or dasatinib monotherapy in clonogenic assay. The tumor volume and tumor weight of xenografts were significantly lower in doublet treatment group than those in single-agent treatment groups. Conclusions: Dasatinib plays synergistic role with oxaliplatin in inhibiting gastric cancer cell growth both in vitro and in vivo, via inhibiting Src activity stimulated by oxaliplatin. [ABSTRACT FROM AUTHOR]

Ornithine decarboxylase (ODC), the first rate-limiting enzyme of polyamine biosynthesis, was found to be associated with cell growth, proliferation and transformation. ODC gene expression in gastric cancer was increased and its level was positively correlated with the degree of malignity of gastric mucosa and development of gastric lesions. In order to evaluate the therapeutic effects of antisense RNA of ODC on gastric cancer, an antisense RNA of ODC expressing plasmid pcDNA-ODCr which delivered a 120 bp fragment complementary to the initiation codon of ODC gene was constructed and transfected to gastric cancer cells SGC7901 and MGC803. Expression of ODC in gastric cancer cells was determined by western blot. Cell proliferation was assessed by MTS assay. Cell cycle was analyzed by flow cytometry and Matrigel assay was performed to assess the ability of gastric cancer cell invasiveness. The results showed that the ODC gene expression in gastric cancer cells transfected with the pcDNA-ODCr was downregulated efficiently. Tumor cell proliferation was suppressed significantly, and cell cycle was arrested at G1 phase. Gastric cancer cells had reduced invasiveness after gene transfer. Our study suggested that antisense RNA of ODC expressing plasmid pcDNA-ODCr had antitumor activity by inhibiting the expression of ODC, and downregulation of ODC expression using a gene therapy approach might be a novel therapeutic strategy for gastric cancer. [ABSTRACT FROM AUTHOR]