Suppressed Gastric Cancer Metastasis Research Articles

A novel protein FNDC3B-267aa encoded by circ0003692 inhibits gastric cancer metastasis via promoting proteasomal degradation of c-Myc.

Gastric cancer (GC) ranks fifth in global cancer incidence and third in mortality rate among all cancer types. Circular RNAs (circRNAs) have been extensively demonstrated to regulate multiple malignant biological behaviors in GC. Emerging evidence suggests that several circRNAs derived from FNDC3B play pivotal roles in cancer. However, the role of circFNDC3B in GC remains elusive. We initially screened circFNDC3B with translation potential via bioinformatics algorithm prediction. Subsequently, Sanger sequencing, qRT-PCR, RNase R, RNA-FISH and nuclear-cytoplasmic fractionation assays were explored to assess the identification and localization of circ0003692, a circRNA derived from FNDC3B. qRT-PCR and ISH were performed to quantify expression of circ0003692 in human GC tissues and adjacent normal tissues. The protein-encoding ability of circ0003692 was investigated through dual-luciferase reporter assay and LC/MS. The biological behavior of circ0003692 in GC was confirmed via in vivo and in vitro experiments. Additionally, Co-IP and rescue experiments were performed to elucidate the interaction between the encoded protein and c-Myc. We found that circ0003692 was significantly downregulated in GC tissues. Circ0003692 had the potential to encode a novel protein FNDC3B-267aa, which was downregulated in GC cells. We verified that FNDC3B-267aa, rather than circ0003692, inhibited GC migration in vitro and in vivo. Mechanistically, FNDC3B-267aa directly interacted with c-Myc and promoted proteasomal degradation of c-Myc, resulting in the downregulation of c-Myc-Snail/Slug axis. Our study revealed that the novel protein FNDC3B-267aa encoded by circ0003692 suppressed GC metastasis through binding to c-Myc and enhancing proteasome-mediated degradation of c-Myc. The study offers the potential applications of circ0003692 or FNDC3B-267aa as therapeutic targets for GC.

CircRNA regulates the liquid-liquid phase separation of ATG4B, a novel strategy to inhibit cancer metastasis?

Anoikis is a common programmed death for most of detached cells, but cancer cells can obtain anoikis resistance to facilitate their distant metastasis through the circulation system. Researches have indicated that enhanced autophagic flux accounts for the survival of many cancer cells under detached conditions. Targeting ATG4B, the key factor of autophagy progress, can inhibit cancer metastasis in vitro, but ATG4B-deficient mice are susceptible to many serious diseases, which indicates the potential uncontrolled side effects of direct targeting of ATG4B. In our recent research, we confirmed that ATG4B is a novel RNA binding protein in the gastric cancer (GC) cell. It interacts with circSPECC1 which consequently facilitates the liquid-liquid phase separation and ubiquitination of ATG4B. Additionally, the m6A reader ELAVL1 inhibits the expression of circSPECC1 to enhance the expression of ATG4B and anoikis resistance of GC cells. Further, we screened out an FDA-approved compound, lopinavir, to restore circSPECC1 abundance and suppress GC metastasis. In conclusion, our research identified a novel signal pathway (ELAVL1-circSPECC1-ATG4B-autophagy) to facilitate anoikis resistance and metastasis of GC cells and screened out a compound with clinical application potential to block this pathway, providing a novel strategy for the prevention of GC metastasis.

Calcium Binding Protein S100A16 Expedites Proliferation, Invasion and Epithelial-Mesenchymal Transition Process in Gastric Cancer.

Gastric cancer (GC) is one of the most common malignant tumors of the digestive system, listed as the second cause of cancer-related deaths worldwide. S100 Calcium Binding Protein A16 (S100A16) is an acidic calcium-binding protein associated with several types of tumor progression. However, the function of S100A16 in GC is still not very clear. In this study, we analyzed S100A16 expression with the GEPIA database and the UALCAN cancer database. Meanwhile, 100 clinical GC samples were used for the evaluation of its role in the prognostic analysis. We found that S100A16 is significantly upregulated in GC tissues and closely correlated with poor prognosis in GC patients. Functional studies reveal that S100A16 overexpression triggers GC cell proliferation and migration both in vivo and in vitro; by contrast, S100A16 knockdown restricts the speed of GC cell growth and mobility. Proteomic analysis results reveal a large S100A16 interactome, which includes ZO-2 (Zonula Occludens-2), a master regulator of cell-to-cell tight junctions. Mechanistic assay results indicate that excessive S100A16 instigates GC cell invasion, migration, and epithelial-mesenchymal transition (EMT) via ZO-2 inhibition, which arose from S100A16-mediated ZO-2 ubiquitination and degradation. Our results not only reveal that S100A16 is a promising candidate biomarker in GC early diagnosis and prediction of metastasis, but also establish the therapeutic importance of targeting S100A16 to prevent ZO-2 loss and suppress GC metastasis and progression.

Circular RNA CDR1as Inhibits the Metastasis of Gastric Cancer through Targeting miR-876-5p/GNG7 Axis.

Circular RNA CDR1as has been demonstrated to participate in various cancer progressions as miRNA sponges. The exact underlying mechanisms of CDR1as on gastric cancer (GC) metastasis remain unknown. Here, we found that CDR1as knockdown facilitated GC cell migration and invasion while its overexpression inhibited the migration and invasion abilities of GC cells in vitro and in vivo. Moreover, epithelial-mesenchymal transition- (EMT-) associated proteins and MMP2 and MMP9 were downregulated by CDR1as. Bioinformatics analysis combined with dual-luciferase reporter gene assays, western blot, RT-qPCR analysis, and functional rescue experiments demonstrated that CDR1as served as a miR-876-5p sponge and upregulated the target gene GNG7 expression to suppress GC metastasis. In summary, our findings indicate that CDR1as suppresses GC metastasis through the CDR1as/miR-876-5p/GNG7 axis.

Histone Methyltransferase SETD1A Induces Epithelial-Mesenchymal Transition to Promote Invasion and Metastasis Through Epigenetic Reprogramming of Snail in Gastric Cancer.

Aberrant epigenetic modification induces oncogene expression and promotes cancer development. The histone lysine methyltransferase SETD1A, which specifically methylates histone 3 lysine 4 (H3K4), is involved in tumor growth and metastasis, and its ectopic expression has been detected in aggressive malignancies. Our previous study reported that SETD1A promotes gastric cancer (GC) proliferation and tumorigenesis. However, the function and molecular mechanisms of SETD1A in GC metastasis remain to be elucidated. In this study, we found that overexpression of SETD1A promoted GC migration and invasion, whereas knockdown of SETD1A suppressed GC migration and invasion in vitro. Moreover, knockdown of SETD1A suppressed GC epithelial-mesenchymal transition (EMT) by increasing the expression of epithelial marker E-cadherin and decreasing the expression of mesenchymal markers, including N-cadherin, Fibronectin, Vimentin, and α-smooth muscle actin (α-SMA). Mechanistically, knockdown of SETD1A reduced the EMT key transcriptional factor snail expression. SETD1A was recruited to the promoter of snail, where SETD1A could methylate H3K4. However, knockdown of SETD1A decreased the methylation of H3K4 on the snail promoter. Furthermore, SETD1A could be a coactivator of snail to induce EMT gene expression. Rescue of snail restored SETD1A knockdown-induced GC migration and invasion inhibition. In addition, knockdown of SETD1A suppressed GC metastasis in vivo. In summary, our data revealed that SETD1A mediated the EMT process and induced metastasis through epigenetic reprogramming of snail.

COX-2 promotes metastasis and predicts prognosis in gastric cancer via regulating mTOR.

Aim: Gastric cancer (GC) is one of the most common malignant tumors in the world. It is important to find accurate and reliable biomarkers in order to decrease whole morbidity and mortality. Results: We examined the expression of COX-2 and mTOR on GC tissue microarrays by immunohistochemistry. Multivariate COX regression analysis showed that the expression of COX-2 or mTOR was an independent factor in the prognosis of GC patients. In addition, COX-2 and mTOR have a potentially synergistic effect on predicting the prognosis of GC. Conclusion: The combined expression of COX-2 and mTOR could serve as efficient prognostic indicators and COX-2 could suppress GC metastasis via regulating mTOR.

Zic1 suppresses gastric cancer metastasis by regulating Wnt/β-catenin signaling and epithelial-mesenchymal transition.

Gastric cancer (GC) patients with metastasis had limited treatment options and dismal outcome. We have previously reported the aberrant expression of Zic family member 1 (Zic1) in GC. However, the functional roles and underlying mechanism of Zic1 in GC metastasis remain unknown. Here, we demonstrate that lower expression of Zic1 was correlated with more lymph node metastasis and poor outcome of GC patients. Ectopic expression of Zic1 suppressed both lung metastasis and peritoneal tumor dissemination of GC in mice. The metastatic suppressing ability of Zic1 was mediated by regulating the process of cell invasion, adhesion and epithelial-mesenchymal transition (EMT). Mechanistically, Zic1 could downregulate Wnt targets including c-Myc and Cyclin D1 by inhibiting LEF transcriptional activity in GC cells. Notably, Zic1 was inversely related to the expression of Cyclin D1 in GC tissues tested. In addition, Zic1 could physically interact with β-catenin/transcription factor 4 (TCF4) and disrupt their complex formation, while not affecting β-catenin nuclear localization. Collectively, our study indicated that Zic1 suppressed GC metastasis through attenuating Wnt/β-catenin signaling and the EMT process. Our work may provide novel therapeutic strategies for the metastasis of GC.

Decreased expression of the long noncoding RNA LINC00261 indicate poor prognosis in gastric cancer and suppress gastric cancer metastasis by affecting the epithelial-mesenchymal transition.

BackgroundRecent evidence indicates that long noncoding RNAs (lncRNAs) play pivotal roles in the regulation of cellular processes and are found to be dysregulated in a variety of cancers. LINC00261 is an lncRNA that is aberrantly expressed in gastric cancer (GC). The clinical role of LINC00261 in GC and molecular mechanisms remains to be found.MethodsReal-time polymerase chain reaction (PCR) was used to examine LINC00261 expression in GC cell lines/tissues compared with normal epithelial cells/adjacent non-tumorous tissues. Gain and loss of function approaches were used to investigate the biological role of LINC00261 in GC cells. The effects of LINC00261 on cell viability were evaluated by MTT and colony formation assays. Wound healing assay, cell migration and invasion assays, and nude mice were used to examine the effects of LINC00261 on tumor cell metastasis in vitro and in vivo. Protein levels of LINC00261 targets were determined by western blot and immunohistochemistry.ResultsLINC00261 was downregulated in GC cell lines and cancerous tissues, as compared with normal gastric epithelial cells and adjacent noncancerous tissue samples. Low LINC00261 expression was correlated with deeper tumor invasion (P < 0.001), higher tumor stage (P = 0.013), and lymphatic metastasis (P = 0.006). Univariate and multivariate analyses indicated that low LINC00261 expression predicted poor prognosis. Ectopic expression of LINC00261 impaired cell migration and invasion, leading to the inhibition of metastasis in vitro and in vivo. Knockdown of LINC00261 expression promoted cell migration and invasion in vitro. Overexpression of LINC00261 was found to play a key role in epithelial–mesenchymal transition (EMT) through the regulation of E-cadherin, N-cadherin, and Vimentin expression.ConclusionsLow expression of the lncRNA LINC00261 occurs in GC and is associated with poor prognosis. LINC00261 suppresses GC metastasis by regulating EMT. Thus, LINC00261 plays an important role in the progression and metastasis of GC.Electronic supplementary materialThe online version of this article (doi:10.1186/s13045-016-0288-8) contains supplementary material, which is available to authorized users.

POU2F2-oriented network promotes human gastric cancer metastasis

Background and aimsAberrant upregulation of POU2F2 expression has been discovered in metastatic gastric cancer (GC). However, the mechanisms underlying the aberrant upregulation and the potential functions of POU2F2 remain uncertain.DesignThe...

942 Epigenetic Silencing of DACH1 Induces the Invasion and Migration of Gastric Cancer by Activating TGF-β Signaling

Gastric cancer (GC) is the fourth most common malignancy in males and the fifth most common malignancy in females worldwide and a leading cause of cancer death. Loss of DACH1 expression was found in breast, prostate, endometrial cancer, hepatocellular carcinoma and colorectal cancer. To analyze the regulation and the function of DACH1 in GC, 8 gastric cancer cell lines, 8 cases of normal mucosa and 98 cases of primary GC were employed in this study. Loss of DACH1 expression is correlated with promoter region hypermethylation and re-expression of DACH1 was induced by 5-Aza-2'-deoxyazacytidine treatment in GC cell lines. DACH1 is frequently methylated in primary GC and methylation of DACH1 is associated with reduction of DACH1 expression (p<0.01). These results suggest that DACH1 expression was regulated by promoter region hypermethylation in GC. DACH1 methylation was associated with late tumor stage (p<0.01) and lymph node metastasis (p<0.05). Re-expression of DACH1 suppressed SBE4 luciferase reporter activity and inhibited TGF-β signaling by reducing the level of phosphorylated Smad2. DACH1 inhibited epithelialmesenchymal transition (EMT) and metastasis of GC by inhibition of TGF-β signaling. The tumor size is smaller in DACH1 re-expressed BGC823 cell xenograft than in control group (p<0.01). Restoration of DACH1 expression induced G2/M phase arrest and sensitized GC cells to docetaxel. In conclusion, DACH1 is frequently methylated in human GC and methylation of DACH1 may serve as detective and prognostic markers in GC. DACH1 serve as a tumor suppresser both in vitro and in vivo, suppressed GC metastasis by inhibiting TGFβ signaling. Silencing of DACH1 expression may cause resistance of GC cells to docetaxel.

P2.29 miR-148a has a Therapeutic Potential to Suppress Gastric Cancer Metastasis

ABSTRACT Gastric cancer (GC) is the second leading cause of cancer-related death worldwide, with an estimated one million new cases per year. Approximately 50 % of cases occur in Eastern Asia (mainly in China). In most patients, GC is diagnosed at advanced stage frequently accompanied by extensive invasion and lymphatic metastasis, successful therapeutic strategies are limited and the mortality is high. Therefore, investigations into the molecular mechanisms involving in GC progression have major importance and may tend to develop novel avenues for targeted therapy. MicroRNAs (miRNAs) have been documented playing a critical role in cancer development and progression. In this study, we investigate the role of miR-148a in gastric cancer (GC) metastasis. We found that miR-148a expression was suppressed by more than 4 folds in GC compared with their corresponding non-tumorous tissues (90 paired), and the downregulated miR-148a was significantly associated with TNM stage and lymph-node metastasis. Functional assays demonstrated that overexpression of miR-148a suppressed GC cell migration and invasion in vitro and lung metastasis formation in vivo. In addition, we found that miR-148a could target RhoA/ROCK signaling pathway through downregulating ROCK1. Overexpression of miR-148a in GC cells could reduce the mRNA and protein levels of ROCK1, whereas miR-148a silencing significantly increased ROCK1 expression. Luciferase assays confirmed that miR-148a could directly bind to the two sites of 3' untranslated region of ROCK1. Moreover, in GC tissues, we observed an inverse correlation between miR-148a and ROCK1 expression. Knockdown of ROCK1 significantly inhibited GC cell migration and invasion resembling that of miR-148a overexpression. We further found that ROCK1 was involved in miR-148a-induced suppression of GC cell migration and invasion. Taken together, our results show that miR-148a functions as a tumor metastasis suppressor in GC, and downregulation of miR-148a contributes to GC lymph-node metastasis and progression. By understanding the function and molecular mechanism of miR-148a in GC, miR-148a may have a therapeutic potential to suppress GC metastasis. (Clin Cancer Res; 17(24); 7574-83) Download : Download full-size image Fig. 1 . miR-148a is downregulated in GC and associated with advanced clinical stage and lymph-node metastasis.