Gamma-aminobutyric Acid Type A Receptor Subunit Delta as a Potential Therapeutic Target in Gastric Cancer.

BACKGROUND: Novel therapeutic targets are needed to improve the poor prognosis of patients with advanced gastric cancer. The aim of this study was to identify a novel therapeutic target for the treatment of GC and to investigate the potential therapeutic value of an antibody raised against the target. METHODS: We identified gamma-aminobutyric acid type A receptor subunit delta as a candidate therapeutic target by differential transcriptome analysis of metastatic GC tissue and adjacent nontumor tissues. GABRD mRNA levels were analyzed in 230 pairs of gastric tissue by quantitative reverse-transcription polymerase chain reaction. GABRD function was assessed in proliferation, invasion, and apoptosis assays in human GC cell lines expressing control or GABRD-targeting small interfering RNA (siRNA). Mouse anti-human polyclonal GABRD antibodies were generated and assessed for inhibition of GC cell growth in vitro and in a mouse xenograft model of peritoneal GC dissemination. RESULTS: High GABRD mRNA expression level in primary human GC tissue was associated with poor prognosis. Expression of siGABRD in GC cell lines significantly decreased cell proliferation and invasion and increased apoptosis compared with control siRNA expression. Anti-GABRD polyclonal antibodies inhibited GC cell proliferation in vitro and decreased peritoneal tumor nodule size in the mouse xenograft model. CONCLUSION: We identified GABRD as novel regulator of GC cell growth and function. GABRD is upregulated in GC tissue and is associated with poor prognosis, suggesting that it may be a potential therapeutic target for GC.

SLC7A9 as a Potential Biomarker for Lymph Node Metastasis of Esophageal Squamous Cell Carcinoma.

BACKGROUND: The expression of solute carrier (SLC) 7 family genes is reportedly associated with several malignancies. Here, we focused on SLC7A9 and investigated its expression, function, and clinical significance in esophageal squamous cell carcinoma (ESCC). METHODS: SLC7A9 transcription levels were evaluated in 13 ESCC cell lines, and polymerase chain reaction (PCR) array analysis was conducted to detect coordinately expressed genes with SLC7A9. SLC7A9 contributions to proliferation, invasion, and migration were evaluated in ESCC cells subjected to siRNA-mediated gene knockdown and pCMV6-entry plasmid-mediated overexpression. SLC7A9 expression was detected in 189 ESCC tissues by quantitative reverse-transcription (qRT)-PCR and correlated with clinicopathological parameters. RESULTS: The expression levels of SLC7A9 varied widely in ESCC cell lines and correlated with FGFBP1 expression. Knockdown of SLC7A9 significantly suppressed the proliferation, invasion, and migration of the ESCC cell lines. Moreover, overexpression of SLC7A9 enhanced cell proliferation and migration. In analyses of clinical specimens, SLC7A9 mRNA was overexpressed in the ESCC tissues compared with the adjacent normal esophageal tissues. High mRNA expression was significantly associated with high levels of squamous cell carcinoma-related antigen and carcinoembryonic antigen, advanced disease stage, and lymph node metastasis. High SLC7A9 expression was also significantly associated with poor disease-specific and disease-free survival, and lymph node recurrence after radical surgery, but not with the other recurrence patterns. On multivariate analysis, high SLC7A9 expression was an independent predictor of lymph node recurrence. CONCLUSIONS: SLC7A9 influences the malignant behavior of ESCC cells. Tumor SLC7A9 expression may serve as a novel biomarker for predicting lymph node metastasis and recurrence in ESCC patients.

Lysosomal-associated membrane protein family member 5 promotes the metastatic potential of gastric cancer cells.

BACKGROUND: Metastatic gastric cancer (GC) has a poor prognosis, and elucidating the molecular mechanisms involved in metastasis may lead to the development of novel therapeutic modalities. METHODS: Transcriptome analysis of surgically resected metastatic tissue from GC patients and noncancerous tissue was performed to identify novel metastasis-related genes. Analyses of in vitro cell function, apoptosis, the cell cycle and cancer stemness were performed using GC cell lines with a stable knockout of a candidate gene. In vivo percutaneous, peritoneal dissemination and liver metastasis xenograft models were also generated. PCR array and proteome analyses were performed. Expression of the candidate gene was analyzed in GC tissues from 300 patients. RESULTS: Lysosomal Associated Membrane Protein Family Member 5 (LAMP5) was upregulated in the metastatic tissues. LAMP5 knockout significantly suppressed proliferation, invasion, and migration of GC cells and increased apoptosis, cell cycle arrest and cancer stemness. LAMP5 knockout virtually suppressed tumor growth in in vivo percutaneous, peritoneal dissemination and liver metastasis models. EMT- and autophagy-related genes were associated with LAMP5. High LAMP5 mRNA levels were significantly associated with a worse prognosis. CONCLUSION: LAMP5 plays a vital role in metastasis formation and may be a promising novel target of drug development for metastatic GC in the future.

Hepatic metastasis of gastric cancer is associated with enhanced expression of ethanolamine kinase 2 via the p53-Bcl-2 intrinsic apoptosis pathway.

BACKGROUND: Gastric cancer (GC) with hepatic metastasis has a poor prognosis. Understanding the molecular mechanisms involved in hepatic metastasis may contribute to the development of sensitive diagnostic biomarkers and novel therapeutic strategies. METHODS: We performed transcriptome analysis of surgically resected specimens from patients with advanced GC. One of the genes identified as specifically associated with hepatic metastasis was selected for detailed analysis. GC cell lines with knockout of the candidate gene were evaluated in vitro and in vivo. Expression of the candidate gene was analysed in GC tissues from 300 patients. RESULTS: Ethanolamine kinase 2 (ETNK2) was differentially upregulated in GC patients with hepatic metastasis. ETNK2 expression was elevated in GC cell lines derived from haematogenous metastases. ETNK2 knockout significantly suppressed proliferation, invasion, and migration; increased apoptosis; reduced Bcl-2 protein expression; and increased phosphorylated p53 expression. In mouse xenograft models, ETNK2 knockout virtually abolished hepatic metastasis. Stratification of GC patients based on ETNK2 mRNA level revealed significant associations between high ETNK2 tumour expression and both hepatic recurrence and worse prognosis. CONCLUSIONS: Upregulation of ETNK2 in GC enhances hepatic metastasis, possibly via dysregulation of p53-Bcl-2-associated apoptosis. ETNK2 expression may serve as a biomarker for predicting hepatic recurrence and a therapeutic target.

G-protein subunit gamma-4 expression has potential for detection, prediction and therapeutic targeting in liver metastasis of gastric cancer.

BACKGROUND: The liver is the most common site for haematogenous metastasis of gastric cancer, and liver metastasis is fatal. METHODS: We conducted a transcriptomic analysis between metastatic foci in the liver, primary tumour and adjacent tissues from gastric cancer patients with metastasis limited to the liver. We determined mRNA expression levels in tumour tissues of 300 patients with gastric cancer via quantitative RT-PCR. The oncogenic phenotypes of GNG4 were determined with knockdown, knockout and forced expression experiments. We established and compared subcutaneous and liver metastatic mouse xenograft models of gastric cancer to reveal the roles of GNG4 in tumorigenesis in the liver. RESULTS: GNG4 was upregulated substantially in primary gastric cancer tissues as well as liver metastatic lesions. High levels of GNG4 in primary cancer tissues were associated with short overall survival and the likelihood of liver recurrence. Functional assays revealed that GNG4 promoted cancer cell proliferation, the cell cycle and adhesiveness. Tumour formation by GNG4-knockout cells was moderately reduced in the subcutaneous mouse model and strikingly attenuated in the liver metastasis mouse model. CONCLUSIONS: GNG4 expression may provide better disease monitoring for liver metastasis, and GNG4 may be a novel candidate therapeutic target for liver metastasis.

Therapeutic monoclonal antibody targeting of neuronal pentraxin receptor to control metastasis in gastric cancer.

BACKGROUND: Controlling metastasis is essential for improving the prognosis of patients with gastric cancer (GC). Here, we aimed to identify a molecule required for GC metastasis and to investigate its potential utility as a target for the development of therapeutic antibodies (Abs). METHODS: Transcriptome and bioinformatics analyses of human GC cell lines identified the neuronal pentraxin receptor (NPTXR) as a candidate molecule. NPTXR function was probed by modulating its expression in GC cells and assessing the effects on intracellular signaling and malignant behaviors in vitro and in mouse xenograft models. We also generated anti-NPTXR Abs and Nptxr-/- mice, and assessed the clinical significance of NPTXR expression in GC specimens. RESULTS: NPTXR mRNA expression in clinical specimens was associated with disease progression and was significantly higher in tissues from GC patients with distant metastasis compared with those without. NPTXR regulated expression of genes involved in metastatic behaviors as well as activation of the PI3K-AKT-mTOR, FAK-JNK, and YAP signaling pathways. NPTXR silencing promoted caspase-mediated apoptosis and attenuated GC cell proliferation, cell cycle progression, migration, invasion, adhesion, stem cell-like properties, and resistance to 5-fluorouracil in vitro, and also inhibited the tumorigenicity of GC cells in vivo. Anti-NPTXR Abs inhibited GC peritoneal metastasis in mice. Nptxr-/- mice showed no abnormalities in reproduction, development, metabolism, or motor function. CONCLUSIONS: NPTXR plays an essential role in controlling the malignant behavior of GC cells in vitro and in vivo. NPTXR-targeting Abs may thus have utility as novel diagnostic tools and/or treatment modalities for GC.

Expression and Malignant Potential of B4GALNT4 in Esophageal Squamous Cell Carcinoma.

BACKGROUND: ß-1,4-N-Acetyl-galactosaminyltransferase 4 (B4GALNT4), an enzyme involved in ganglioside synthesis, is upregulated in many cancers. We examine B4GALNT4 expression and its relationship to prognosis in esophageal squamous cell carcinoma (ESCC). PATIENTS AND METHODS: Expression of B4GALNT4 mRNA and B4GALNT4 protein was analyzed by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry, respectively, in 17 human ESCC cell lines and/or clinical specimens from two independent cohorts of 147 and 159 ESCC patients. The contributions of B4GALNT4 to proliferation, invasion, migration, and adhesion was evaluated in ESCC cells subjected to siRNA-mediated gene knockdown. Correlations between clinicopathological parameters and B4GALNT4 expression in clinical specimens were analyzed in both patient cohorts. RESULTS: B4GALNT4 mRNA expression levels varied widely in ESCC cell lines, regardless of differentiation status or the originating tissue. Knockdown of B4GALNT4 significantly suppressed the proliferation, invasion, migration, and adhesion of ESCC cell lines compared with control cells. B4GALNT4 mRNA was overexpressed in ESCC tissues compared with adjacent normal esophageal tissues. High mRNA expression was significantly associated with poor disease-free survival and hematogenous recurrence, and high B4GALNT4 protein expression was also significantly related to poor disease-specific survival. On multivariable analysis, high B4GALNT4 expression was an independent predictor of poor prognosis. In both patient cohorts, high B4GALNT4 expression did not correlate with known prognostic factors, such as disease stage, lymphovascular invasion, or squamous cell-carcinoma-related antigen level. CONCLUSIONS: B4GALNT4 influences the malignant behavior of ESCC cells. B4GALNT4 expression may serve as a novel prognostic marker, independent of established risk factors, for ESCC patients.

PRAME as a Potential Biomarker for Liver Metastasis of Gastric Cancer.

BACKGROUND: Liver metastasis of gastric cancer (GC) is highly associated with poor prognosis. The development of sensitive biomarkers for detecting and predicting liver metastasis is required for better clinical outcome. OBJECTIVE: In this study, we aimed to identify novel genes associated with liver metastasis of GC. METHODS: Global expression profiling of 57,749 genes was performed using surgically resected gastric tissues from four patients with liver metastasis to identify candidate genes. The mRNA expression levels of the selected candidate gene were analyzed in the resected gastric tissues of 300 GC patients and correlated with clinicopathological parameters. Fourteen GC cell lines were subjected to mRNA expression and polymerase chain reaction (PCR) array analysis. RESULTS: Among 25 candidate genes identified by transcriptome analysis, preferentially expressed antigen of melanoma (PRAME) was selected for subsequent analyses. mRNA expression analysis of clinical samples revealed the aberrant expression of PRAME in GC tissues, and its high expression was significantly related to differentiated phenotype and vessel invasion, as well as liver metastasis. High PRAME expression was significantly associated with hepatic recurrence after curative surgery, and cumulative incidences of hepatic recurrence were significantly greater in patients with high PRAME expression compared with patients with low PRAME expression. In an in vitro analysis, overexpression was observed in all GC cell lines compared with a normal epithelial cell line. PCR array analysis revealed the coordinate expression of MMP9, OCLN, IL1RN, and MST1R. CONCLUSIONS: PRAME is related to the malignant potential of GC and could serve as a novel biomarker for the detection and prediction of liver metastasis.

Troponin I2 as a Specific Biomarker for Prediction of Peritoneal Metastasis in Gastric Cancer.

BACKGROUND: Although peritoneal metastasis is a serious concern in patients with gastric cancer, no acceptable and specific biomarker is available. We aimed to identify a candidate biomarker to predict peritoneal metastasis of gastric cancer. METHODS: Metastatic pathway-specific transcriptome analysis was conducted by comparison of patient groups with no recurrence and with peritoneal, hepatic, and nodal recurrence. Fifteen cell lines and 262 pairs of surgically resected gastric tissues were subjected to messenger RNA (mRNA) expression analysis. Polymerase chain reaction array analysis was performed to explore coordinately expressed cancer-related genes. To evaluate the in situ protein localization and expression patterns, immunohistochemical staining was performed. RESULTS: From transcriptome data, troponin I2 (TNNI2) was identified as a candidate molecule specifically overexpressed in gastric cancer prone to peritoneal metastasis. TNNI2 mRNA was expressed at differential levels, independent of differentiated phenotype of cell lines. Epithelial to mesenchymal transition-related genes, tumor inhibitor of metalloproteinase 1 (TIMP1), and vacuolar protein sorting 13 homolog A (VPS13A) were expressed with TNNI2 at correlation coefficient > 0.7. The optimal cutoff of TNNI2 expression was determined as 0.00017. High TNNI2 expression was significantly and specifically associated with peritoneal metastasis and served as an independent risk marker for peritoneal recurrence after curative gastrectomy. Prevalence of peritoneal recurrence increased in parallel with staining intensity of TNNI2. CONCLUSIONS: TNNI2 expression in gastric tissues may serve as a specific biomarker for prediction of peritoneal metastasis of gastric cancer and contribute to improvement of patient management.

Sturge-Weber syndrome with cemento-ossifying fibroma in the maxilla and giant odontoma in the mandible: A case report.

Sturge-Weber syndrome (SWS) is a neurocutaneous syndrome with vascular lesions of the cerebral meninges, port wine spots on the face, and glaucoma of the eyes; it is a congenital, non-genetic disease whose etiology and mechanisms are unknown. In this report, we describe a rare case of SWS with unilateral large odontogenic tumors in the maxilla and mandible. The histopathological diagnosis of the maxillary bone lesion on biopsy was juvenile psammomatoid ossifying fibroma, which is considered a type of ossifying fibroma of craniofacial bone origin. However, the final pathological diagnosis of the excision was cemento-ossifying fibroma derived from periodontal ligament cells, and we discuss the histopathology in detail. In addition, the mandibular lesion was one of the largest odontomas reported to date. Furthermore, in this case, we suggest the possibility that the maxillary and mandibular bone lesions are not separate lesions, but a series of lesions related to SWS.

Targeting Pancreatic Cancer with Novel Plumbagin Derivatives: Design, Synthesis, Molecular Mechanism, In Vitro and In Vivo Evaluation.

Pancreatic tumors grow in an "austerity" tumor microenvironment characterized by nutrient deprivation and hypoxia. This leads to the activation of adaptive pathways in pancreatic cancer cells, promoting tolerance to nutrition starvation and aggressive malignancy. Conventional anticancer drugs are often ineffective against tumors that grow in such austerity condition. Plumbagin, a plant-derived naphthoquinone, has shown potent preferential cytotoxicity against pancreatic cancer cells under nutrient-deprived conditions. Therefore, we synthesized a series of plumbagin derivatives and found that 2-(cyclohexylmethyl)-plumbagin (3f) was the most promising compound with a PC50 value of 0.11 µM. Mechanistically, 3f was found to inhibit the PI3K/Akt/mTOR signaling pathways, leading to cancer cell death under nutrient-deprived conditions. In vivo studies using pancreatic cancer xenograft mouse models confirmed the efficacy of 3f, demonstrating significant inhibition of tumor growth in a dose-dependent manner. Compound 3f represents a highly promising lead for anticancer drug development based on an antiausterity strategy.

Blockade of CHRNB2 signaling with a therapeutic monoclonal antibody attenuates the aggressiveness of gastric cancer cells.

Here, we evaluated the therapeutic potential of antibodies (Abs) targeting cholinergic receptor nicotinic beta 2 subunit (CHRNB2) in gastric cancer. To investigate the effects of these Abs on malignant phenotypes in vitro and in mouse xenograft models, we generated gene knockouts through genome editing, performed RNA interference-mediated knockdown of gene expression, and ectopically expressed CHRNB2 in gastric cancer cells. The effects of anti-CHRNB2 Abs on the proliferation of cancer cells were evaluated both in vitro and in vivo. We determined the effects of Chrnb2 deficiency on mice and the clinical significance of CHRNB2 expression in gastric cancer clinical specimens. Knockdown of CHRNB2 attenuated gastric cancer cell proliferation, whereas forced overexpression of CHRNB2 increased cell proliferation. Knockout of CHRNB2 significantly influenced cell survival and functions associated with metastasis. The effects of polyclonal Abs targeting the C- and N-termini of CHRNB2 guided the development of anti-CHRNB2 monoclonal Abs that inhibited the growth of gastric cancer cells in vitro and in vivo. Pathway analysis revealed that CHRNB2 interfered with signaling through the PI3K-AKT and JAK-STAT pathways. Chrnb2-deficient mice exhibited normal reproduction, organ functions, and motor functions. CHRNB2 regulates multiple oncological phenotypes associated with metastasis, and blockade of CHRNB2 expression using specific Abs shows promise for controlling metastasis in gastric cancer.

Amido-Bridged Nucleic Acid-Modified Antisense Oligonucleotides Targeting SYT13 to Treat Peritoneal Metastasis of Gastric Cancer.

Patients with peritoneal metastasis of gastric cancer have dismal prognosis, mainly because of inefficient systemic delivery of drugs to peritoneal tumors. We aimed to develop an intraperitoneal treatment strategy using amido-bridged nucleic acid (AmNA)-modified antisense oligonucleotides (ASOs) targeting synaptotagmin XIII (SYT13) and to identify the function of SYT13 in gastric cancer cells. We screened 71 candidate oligonucleotide sequences according to SYT13-knockdown efficacy, in vitro activity, and off-target effects. We evaluated the effects of SYT13 knockdown on cellular functions and signaling pathways, as well as the effects of intraperitoneal administration to mice of AmNA-modified anti-SYT13 ASOs. We selected the ASOs (designated hSYT13-4378 and hSYT13-4733) with the highest knockdown efficiencies and lowest off-target effects and determined their abilities to inhibit cellular functions associated with the metastatic potential of gastric cancer cells. We found that SYT13 interfered with focal adhesion kinase (FAK)-mediated intracellular signals. Intraperitoneal administration of hSYT13-4378 and hSYT13-4733 in a mouse xenograft model of metastasis inhibited the formation of peritoneal nodules and significantly increased survival. Reversible, dose- and sequence-dependent liver damage was induced by ASO treatment without causing abnormal morphological and histological changes in the brain. Intra-abdominal administration of AmNA-modified anti-SYT13 ASOs represents a promising strategy for treating peritoneal metastasis of gastric cancer.

Survival times are similar among patients with peritoneal, hematogenous, and nodal recurrences after curative resections for gastric cancer.

BACKGROUND: The three dominant recurrence patterns of gastric cancer are peritoneal, hematogenous, and nodal recurrence. Correlation between initial recurrence site and prognosis is poorly understood, particularly after standardization of postoperative S-1 adjuvant chemotherapy. METHODS: We analyzed a multi-institutional database of 3484 patients who underwent gastrectomy for gastric cancer between 2010 and 2014. Patients who experienced recurrences after curative gastrectomy classified into peritoneal, hematogenous, or nodal recurrence groups, according to their initial recurrence sites, and their prognoses were compared. RESULTS: We included 313 patients in the analysis, of whom 190 patients (63%) were treated with postoperative adjuvant chemotherapy. Pathological disease states were stage I: n = 20 (6%), stage II: n = 62 (20%), and stage III: n = 231 (74%). Patients were categorized into groups by peritoneal (n = 127), hematogenous (n = 123), and nodal (n = 63) recurrence. The peritoneal recurrence group tended to have longer recurrence-free survival, but shorter post-recurrence survival, than the other two groups. Median disease-specific survival after curative resection by group were peritoneal: 25.8 months, hematogenous: 29.0 months, and nodal: 27.8 months (peritoneal vs hematogenous, P = .152; hematogenous vs nodal, P = .955; peritoneal vs nodal, P = .213). CONCLUSIONS: Prognoses after curative resection for gastric cancer were similar among patients with peritoneal, hematogenous, or nodal recurrences.

Chromobox 2 Expression Predicts Prognosis After Curative Resection of Oesophageal Squamous Cell Carcinoma.

BACKGROUND/AIM: To investigate the function of chromobox 2 (CBX2) in oesophageal squamous cell carcinoma (OSCC). MATERIALS AND METHODS: We used real-time quantitative reverse transcription PCR (qRT-PCR) and immunohistochemistry to determine CBX2 expression levels in 13 human OSCC cell lines and clinical specimens of two independent cohorts of patients with OSCC. RESULTS: PCR array analysis revealed that CBX2 was co-ordinately expressed with WNT5B in OSCC cell lines. RT-qPCR analysis of clinical samples revealed a high tumour-specific CBX2 expression compared with normal oesophageal tissues. High CBX2 expression was significantly associated with shorter disease-specific survival, hematogenous recurrence, and overall recurrence. Analysis of tissue microarrays of one cohort revealed that patients with higher CBX2 levels tended to have a shorter disease-specific survival. CONCLUSION: CBX2 overexpression in OSCC tissues may serve as a novel biomarker for predicting survival and hematogenous recurrence.

Localization of antimicrobial peptides human beta-defensins in minor salivary glands with Sjögren's syndrome.

Sjögren's syndrome is a common systemic autoimmune disease associated with inflammatory cells that infiltrate exocrine glands. The antimicrobial peptides human beta-defensin-1, human beta-defensin-2, and human beta-defensin-3 are expressed in various human epithelial cells and in normal salivary glands. Antimicrobial peptides provide local protection against infection and participate in inflammatory responses. Because of the presence of inflammation, we hypothesized that human beta-defensin expression in minor salivary glands may be increased in subjects with Sjögren's syndrome. However, the expression of human beta-defensins 1 and 2 was decreased in salivary glands affected by Sjögren's syndrome in comparison with the human beta-defensin expression patterns in salivary glands from normal subjects. In addition, the reduction in expression of human beta-defensin-2 was greater than the reduction in expression of human beta-defensin-1. The aforementioned result suggests that the reduction in expression of human beta-defensin-2 may occur earlier than the reduction in expression of human beta-defensin-1, which may lead to a greater decrease in human beta-defensin-2 than in human beta-defensin-1 during disease progression.

PRAME Expression as a Potential Biomarker for Hematogenous Recurrence of Esophageal Squamous Cell Carcinoma.

BACKGROUND/AIM: To investigate the function of preferentially expressed antigen of melanoma (PRAME) in esophageal squamous cell carcinoma (ESCC). MATERIALS AND METHODS: mRNA expression levels of PRAME were analyzed in resected esophageal tissues of 150 ESCC patients and correlated with clinicopathological parameters. We also investigated the potential function of PRAME by analyzing coordinately expressed genes in 13 ESCC cell lines. RESULTS: RT-qPCR analysis of clinical samples revealed aberrantly high PRAME expression in tumors compared with normal esophageal tissues. High PRAME expression was significantly associated with shorter disease-specific survival and hematogenous recurrence, but not with overall recurrence. The cumulative incidence of hematogenous recurrence was significantly greater for patients with high compared to those with low PRAME expression. In vitro, PCR array analysis revealed that PRAME was coordinately expressed with EGFR, ITGB, and TCF3. CONCLUSION: PRAME is overexpressed in ESCC tissues and may serve as a novel biomarker for predicting hematogenous recurrence.