Molecular biological analysis of 5-FU-resistant gastric cancer organoids; KHDRBS3 contributes to the attainment of features of cancer stem cell.

5-FU is one of the key drugs in the treatment of gastric cancer (GC). Much evidence has shown that cancer stem cells (CSCs) play a key role in the acquisition of drug resistance. The organoid is a novel 3D cell culture system technology that sustains stem-cell-driven formation of near-physiological, self-renewing tissues using specific niche factors in a dish. In this study, we established GC organoids (GCOs) and gradually treated them with higher concentrations of 5-FU. We successfully harvested four 5-FU-resistant GCOs, which were supported by significant changes in the expression of molecules related to 5-FU metabolism. We then performed microarray analysis using three normal gastric organoids and three pairs of 5-FU-resistant and parental GCOs. Through the comparison of expression profiles and further validation, we chose KHDRBS3 as a target gene. We found KHDRBS3 to be an independent prognostic factor in GC patients, especially in GC patients treated with 5-FU chemotherapy. We also determined that KHDRBS3 might play an important role in the acquisition of stem cell-like features, such as multi-drug resistance and organoid formation, by regulating CD44 variant expression. We found KHDRBS3, which is thought to play an important role in the acquisition of characteristics of CSCs in GC, to be a promising candidate marker for predicting therapeutic effect and prognosis in GC patients.

Uc.63+ contributes to gastric cancer progression through regulation of NF-kB signaling.

BACKGROUND: The transcribed ultraconserved regions (T-UCRs) are a novel class of long non-coding RNAs and are involved in the development of several types of cancer. Although several different papers have described the oncogenic role of Uc.63+, there are no reports mentioning its importance in gastric cancer (GC) biology. METHODS: In this study, we evaluated Uc.63+ expression using clinical samples of GC by qRT-PCR, and also assessed the correlation between Uc.63+ expression and clinico-pathological factors. RESULTS: The upregulation of Uc.63+ was significantly correlated with advanced clinico-pathological features. Knockdown of Uc.63+ significantly repressed GC cell growth and migration, whereas overexpression of Uc.63+ conversely promoted those of GC cells. In situ hybridization of Uc.63+ revealed its preferential expression in poorly differentiated adenocarcinoma. We further conducted a microarray analysis using MKN-1 cells overexpressing Uc.63- and found that NF-κB signaling was significantly upregulated in accordance with Uc.63+ expression. CONCLUSION: Our results suggest that Uc.63+ could be involved in GC progression by regulating GC cell growth and migration via NF-κB signaling.

Annexin A10 is involved in the induction of pancreatic duodenal homeobox­1 in gastric cancer tissue, cells and organoids.

Gastric cancer (GC) is the third most common cause of cancer­related death in the world. Annexin A10 (ANXA10), a member of the Annexin family, is a calcium­/phospholipid­binding protein; however, little is known concerning its functions. It is still unclear what molecule is involved in the induction of ANXA10. In the present study, we performed immunohistochemistry to evaluate the expression of ANXA10, pancreatic and duodenal homeobox­1 (PDX1) and mucin phenotype markers in 130 GC samples. ANXA10 was detected in 63 (48%) of the 130 GC cases and loss of ANXA10 was significantly correlated with disease progression and poor clinical outcomes in GC. PDX1 was significantly correlated with ANXA10 in GC cases and cell lines. Although PDX1 was not significantly correlated with the GC cases with any of the mucin phenotypes, ANXA10 was preferentially detected in the GC cases with the gastric mucin phenotype. As a further investigation, we generated organoids derived from human GC and identified the duplication of the mucin phenotypes of GC by immunohistochemistry. The repression effect on cell growth that was observed in the ANXA10­knockdown cell lines was also clearly observed in the human gastric organoids. We demonstrated that the expression of ANXA10 was correlated with the gastric mucin phenotype and ANXA10 was involved in the induction of PDX1 expression in GC. We also provided evidence that GC organoids represent a powerful tool for scrutinizing the biology of GC, especially with regard to the mucin phenotype.

Clinicopathological and Prognostic Significance of Epithelial Gremlin1 Expression in Gastric Cancer.

BACKGROUND/AIM: Gastric cancer (GC) is one of the most common malignancies worldwide. Gremlin1 is an antagonist of bone morphogenetic proteins that plays a critical role in several biological processes including cancer biology. MATERIALS AND METHODS: We immunohistochemically examined the expression and distribution of Gremlin1 in non-neoplastic gastric mucosa in a series of 159 GC cases. RESULTS: Among 159 GC primary tumors, 59 (37%) were positive for Gremlin1. Gremlin1-negative GC cases showed significantly more advanced clinicopathologic factors and a trend toward intestinal-type GC. Gremlin1 expression was also frequently observed in MUC5AC-positive and G-type GC cases. Gremlin1-negative GCs had a poorer survival rate than Gremlin1-positive GCs (p=0.002). Univariate and multivariate analyses revealed that Gremlin1 expression is an independent predictor of survival in GCs. CONCLUSION: These results indicate that Gremlin1 could be involved in GC progression and may be a good marker of long-term survival in GC.