Helicobacter pylori CagA-mediated ether lipid biosynthesis promotes ferroptosis susceptibility in gastric cancer.

Helicobacter pylori, particularly cytotoxin-associated gene A (CagA)-positive strains, plays a key role in the progression of gastric cancer (GC). Ferroptosis, associated with lethal lipid peroxidation, has emerged to play an important role in malignant and infectious diseases, but the role of CagA in ferroptosis in cancer cells has not been determined. Here, we report that CagA confers GC cells sensitivity to ferroptosis both in vitro and in vivo. Mechanistically, CagA promotes the synthesis of polyunsaturated ether phospholipids (PUFA-ePLs), which is mediated by increased expression of alkylglycerone phosphate synthase (AGPS) and 1-acylglycerol-3-phosphate O-acyltransferase 3 (AGPAT3), leading to susceptibility to ferroptosis. This susceptibility is mediated by activation of the MEK/ERK/SRF pathway. SRF is a crucial transcription factor that increases AGPS transcription by binding to the AGPS promoter region. Moreover, the results demonstrated that CagA-positive cells are more sensitive to apatinib than are CagA-negative cells, suggesting that detecting the H. pylori CagA status may aid patient stratification for treatment with apatinib.

N4-Acetylcytidine Drives Glycolysis Addiction in Gastric Cancer via NAT10/SEPT9/HIF-1α Positive Feedback Loop.

Anti-angiogenic therapy has long been considered a promising strategy for solid cancers. Intrinsic resistance to hypoxia is a major cause for the failure of anti-angiogenic therapy, but the underlying mechanism remains unclear. Here, it is revealed that N4-acetylcytidine (ac4C), a newly identified mRNA modification, enhances hypoxia tolerance in gastric cancer (GC) cells by promoting glycolysis addiction. Specifically, acetyltransferase NAT10 transcription is regulated by HIF-1α, a key transcription factor of the cellular response to hypoxia. Further, acRIP-sequencing, Ribosome profiling sequencing, RNA-sequencing, and functional studies confirm that NAT10 in turn activates the HIF-1 pathway and subsequent glucose metabolism reprogramming by mediating SEPT9 mRNA ac4C modification. The formation of the NAT10/SEPT9/HIF-1α positive feedback loop leads to excessive activation of the HIF-1 pathway and induces glycolysis addiction. Combined anti-angiogenesis and ac4C inhibition attenuate hypoxia tolerance and inhibit tumor progression in vivo. This study highlights the critical roles of ac4C in the regulation of glycolysis addiction and proposes a promising strategy to overcome resistance to anti-angiogenic therapy by combining apatinib with ac4C inhibition.

Association of peripheral basophils with tumor M2 macrophage infiltration and outcomes of the anti-PD-1 inhibitor plus chemotherapy combination in advanced gastric cancer.

BACKGROUND: Although the anti-programmed death-1 (PD-1) inhibitor plus chemotherapy combination has been approved as the standard first-line treatment for advanced gastric cancer, a proportion of patients do not significantly benefit from this therapy. Who would respond poorly to this treatment and the underlying mechanisms of treatment failure are far from clear. METHODS: We retrospectively analyzed the associations between the peripheral basophils at baseline and clinical outcomes in 63 advanced gastric cancer patients treated with anti-PD-1 plus chemotherapy and 54 patients treated with chemotherapy alone. Immunohistochemistry and immunofluorescence staining in gastric cancer samples were utilized to investigate the basophil-related immunophenotype. RESULTS: The optimal cutoff of basophil count to distinguish responders to anti-PD-1 plus chemotherapy from non-responders was 20.0/µL. Compared with the low basophil group (≤ 20.0/µL, n = 40), the high basophil group (> 20.0/µL, n = 23) had a significantly lower objective response rate (ORR 17.4% vs. 67.5%, p = 0.0001), worse progression-free survival (median PFS 4.0 vs. 15.0 months, p = 0.0003), and worse overall survival (median OS not reached, p = 0.027). Multivariate analyses identified a basophil count of > 20.0/µL as an independent risk factor for a worse ORR (OR 0.040, 95% CI 0.007-0.241, p = 0.0004), worse PFS (HR 3.720, 95% CI 1.823-7.594, p = 0.0003) and worse OS (HR 3.427, 95% CI 1.698-6.917, p = 0.001). In contrast, there was no significant association between peripheral basophil counts and tumor response or survival in the chemotherapy-alone group (p > 0.05). In primary gastric cancer samples, we observed a correlation between higher peripheral basophil counts and the accumulation of tumor-infiltrating basophils (r = 0.6833, p = 0.005). Tumor-infiltrating basophils were found to be spatially proximate to M2 macrophages within TME and positively correlated with tumor M2 macrophage infiltration (r = 0.7234, p = 0.0023). The peripheral basophil counts also had a significant positive correlation with tumor-infiltrating M2 macrophage counts (r = 0.6584, p = 0.003). Further validation in tumor samples treated with the neoadjuvant anti-PD-1 inhibitor plus chemotherapy combination suggests that the peripheral basophils, tumor infiltration of basophils, and M2 macrophages were significantly more abundant in non-responders than in responders (p = 0.0333, p = 0.0007, and p = 0.0066, respectively). CONCLUSIONS: The peripheral basophil count was observed to be a potential biomarker of anti-PD-1 efficacy for advanced gastric cancer. Moreover, basophils may induce an immune-evasive tumor microenvironment by increasing M2 macrophage infiltration, which could be a potential immunotherapeutic target for advanced gastric cancer.

Landscape of exitrons in gastric cancer.

BACKGROUND: Exitron is a new type of non-canonical alternative splicing. Accumulating evidence implies exitron may have pathological function and contribute to another source of anti-tumor immunogenicity in various cancers. Its role in gastric cancer remains poorly understood. Large-scale, multi-omics analysis could comprehensively characterize the landscape of exitrons in gastric cancer, reveal undiscovered mechanism and hopefully identify molecular biomarkers for predicting immunotherapy response. METHODS: We collected datasets from five studies for analysis. RNA sequencing was used for exitron identification. Somatic mutations were detected by whole exome sequencing. Neopeptides were confirmed by proteome mass spectrometry. FINDINGS: 42174 gastric cancer-specific exitrons (GCSEs) were identified in 632 patients. GCSEs were clinically relevant to gender, age, Lauren type, tumor stage and prognosis. Tissue specificity test and pathogenic exitron prediction revealed their unique functional impact. GCSEs were mutually exclusive with mutations and demonstrated both unique and complementary function against TP53 mutation in gastric cancer. We further established splicing regulatory network to reveal upstream regulation of exitron splicing. We also evaluated the immunogenicity and diagnostic potential of GCSEs. Evidence of GCSEs-derived neopeptide expression was validated by whole proteome mass spectrometry. PD-1 and Siglecs were significantly increased in high neoantigen load patients. But exitron-related biomarkers failed to predict immunotherapy response, possibly due to small sample size and insufficient sequencing depth. INTERPRETATION: The present study provided a comprehensive multidimensional landscape of gastric cancer exitrons and underscores insights into underexplored mechanism in gastric cancer pathology. FUNDING: The Guangdong Provincial Key Laboratory of Precision Medicine for Gastroinstestinal Cancer (2020B121201004), the Guangdong Provincial Major Talents Project (No. 2019JC05Y361) and National Natural Science Foundation of China (grant number:82172960 and 81872013).

Fibroblast-derived LPP as a biomarker for treatment response and therapeutic target in gastric cancer.

Association of tumor microenvironment and immune checkpoint (e.g., PD-L1) is important for immune escape, impacting chemotherapy and immunotherapy efficacy. We aimed to investigate biomarkers and therapeutic targets against treatment resistance in gastric cancer. Abundances of tumor-infiltrating immune cells were estimated in multiple datasets. Three patient subgroups (A, B, and C) were identified based on seven types of PD-L1- and IFN-γ-associated immune cells. Patients yielded increased prognosis from subgroup A to C (p = 0.027). Subgroup A was characterized by high activated CD4+ memory T cell infiltration, while more resting CD4+ memory T cells were in subgroup C. Further, a risk score was developed for prognostication. Lipoma preferred partner (LPP), as the hub gene in subgroup-related regulatory network, was upregulated (p < 0.01) and was associated with high risk score (p < 0.001) and poor survival (p < 0.05). Bioinformatics analyses and experiments found that LPP expressed restrictively in fibroblasts and associated with activated CD4+ memory T cell infiltration and tumor growth. High-LPP patients yielded fewer benefits from chemotherapy or immunotherapy, compared with the low-LPP group. We finally identified 28 compounds as sensitive drugs for high-LPP patients. Our findings suggested LPP might be a biomarker for treatment response and therapeutic target in gastric cancer.

CMTM6 promotes migration, invasion, and EMT by interacting with and stabilizing vimentin in hepatocellular carcinoma cells.

BACKGROUND: CKLF like MARVEL transmembrane domain containing 6 (CMTM6) has been associated with the development in many kinds of cancers. However, the roles of CMTM6 in hepatocellular carcinoma (HCC) are largely unknown. Thus, the present study aimed to investigate the function of CMTM6 in HCC. METHODS: We analysed CMTM6 levels and functions using human HCC cell lines, paired HCC and adjacent non-tumorous tissues, and a tissue microarray. CMTM6 expression was silenced using short hairpin RNAs and its was overexpressed from a lentivirus vector. CMTM6 mRNA and protein levels were determined using quantitative real-time reverse transcription PCR and western blotting, respectively. Proliferation, colony formation, migration, and invasion were assessed using a Cell counting kit-8, colony formation, wound-healing, and Matrigel invasion assays, respectively. Immunohistochemistry was used to score the expression of CMTM6 in tissue samples. The localization and binding partners of CMTM6 were investigated using immunofluorescence and coimmunoprecipitation experiments, respectively. A mouse xenograft model was used for in vivo studies. RESULTS: Compared with that in adjacent, non-cancerous tissue, Here, CMTM6 levels were increased in HCC tissue samples. Silencing of CMTM6 suppressed the proliferation, migration, and invasion of HCC cells. Conversely, CMTM6 overexpression enhanced HCC cell invasion, migration, and proliferation. Mechanistically, CMTM6 physically interacts with and stabilizes vimentin, thus inducing epithelial-mesenchymal transition (EMT), which promotes proliferation, migration and invasion. Importantly, in HCC tissues, CMTM6 expression correlated positively with vimentin levels. Poor prognosis of HCC was associated significantly with higher CMTM6 expression. CONCLUSIONS: CMTM6 has an important function in HCC proliferation, migration, and invasion, via its interaction with and stabilization of vimentin. CMTM6 might represent a potential biomarker and therapeutic target to treat HCC.

Identification and validation of methylated differentially expressed miRNAs and immune infiltrate profile in EBV-associated gastric cancer.

BACKGROUND: The recent discovery of cancer/tissue specificity of miRNA has indicated its great potential as a therapeutic target. In Epstein-Barr virus-associated gastric cancer (EBVaGC), host genes are affected by extensive DNA methylation, including miRNAs. However, the role of methylated miRNA in the development of EBVaGC and immune cell infiltration has largely remained elusive. RESULTS: After crossmatching the DNA methylation and expression profile of miRNA and mRNA in the Gene Expression Omnibus (GEO) and the Cancer Genome Atlas Research Network (TCGA), we discovered that miR-129-2-3p was significantly suppressed due to hypermethylation on its enhancer in EBVaGC. The differentially expressed genes (DEGs) added up to 30, among which AKAP12 and LARP6 were predicted to be the target genes of miR-129-2-3p and negatively correlated with patients' survival. Accordingly, miR-129-2-3p was significantly down-regulated in tumor samples in 26 (65%) out of 40 cases in our cohort (P < 0.0001). The proliferation, migration and invasion functions of GC cells were significantly promoted when transfected with miR-129-2-3p inhibitor and suppressed when transfected with mimics or treated with 5-aza-2'-deoxycytidine. Moreover, a comprehensive regulation network was established by combining the putative transcription factors, miRNA-mRNA and protein-protein interaction (PPI) analysis. Pathway enrichment analysis showed that cytokine activity, especially CCL20, was the most prominent biological process in EBVaGC development. Immune cell infiltration analysis demonstrated CD4+ T cell, macrophage and dendritic cell infiltrates were significantly enriched for the prognostic-indicated hub genes. CONCLUSION: This study has provided a comprehensive analysis of differentially expressed miRNAs and mRNAs associated with genome-wide DNA methylation by integrating multi-source data including transcriptome, methylome and clinical data from GEO and TCGA, QPCR of tumor samples and cell function assays. It also gives a hint on the relationships between methylated miRNA, DEGs and the immune infiltration. Further experimental and clinical investigations are warranted to explore the underlying mechanism and validate our findings.

Nuclear MYH9-induced CTNNB1 transcription, targeted by staurosporin, promotes gastric cancer cell anoikis resistance and metastasis.

Rationale: Peritoneal metastasis predicts poor prognosis of gastric cancer (GC) patients, and the underlying mechanisms are poorly understood. Methods: The 2-DIGE, MALDI-TOF/TOF MS and single-cell transcriptome were used to detect differentially expressed proteins among normal gastric mucosa, primary GC and peritoneal metastatic tissues. Lentiviruses carrying shRNA and transcription activator-like effector nuclease technology were used to knock down myosin heavy chain 9 (MYH9) expression in GC cell lines. Immunofluorescence, immune transmission electron microscopy, chromatin fractionation, co-immunoprecipitation, and assays for chromatin immunoprecipitation, dual luciferase reporter, agarose-oligonucleotide pull-down, flow cytometry and cell anoikis were performed to uncover nuclear MYH9-induced ß-catenin (CTNNB1) transcription in vitro. Nude mice and conditional transgenic mice were used to investigate the findings in vivo. Results: We observed that MYH9 was upregulated in metastatic GC tissues and was associated with a poor prognosis of GC patients. Mechanistically, we confirmed that MYH9 was mainly localized in the GC cell nuclei by four potential nuclear localization signals. Nuclear MYH9 bound to the CTNNB1 promoter through its DNA-binding domain, and interacted with myosin light chain 9, ß-actin and RNA polymerase II to promote CTNNB1 transcription, which conferred resistance to anoikis in GC cells in vitro and in vivo. Staurosporine reduced nuclear MYH9 S1943 phosphorylation to inhibit CTNNB1 transcription, Wnt/ß-catenin signaling activation and GC progression in both orthotropic xenograft GC nude mouse and transgenic GC mouse models. Conclusion: This study identified that nuclear MYH9-induced CTNNB1 expression promotes GC metastasis, which could be inhibited by staurosporine, indicating a novel therapy for GC peritoneal metastasis.

CD73 promotes tumor metastasis by modulating RICS/RhoA signaling and EMT in gastric cancer.

Tumor microenvironment plays vital roles in shaping cancer diversity, and CD73 (ecto-5'-nucleotidase; NT5E) is an emerging immune checkpoint in modulating cancer progression via conversion of immunostimulatory ATP into immunosuppressive adenosine. However, how the CD73 is regulated and how it functions in the progression of cancer are largely unknown. Here, we showed that CD73 was overexpressed and correlated with poor prognosis of gastric cancer. CD73 links adenosinergic signaling in microenvironment switching to induction of epithelial-to-mesenchymal transition phenotype in gastric cancer during metastasis. Further pathway and gene set enrichment analysis of transcriptome data revealed the modulation role of CD73 in RICS/RhoA signaling by its extracellular function in adenosinergic pathway, which subsequently inhibited phosphorylation of LIMK/cofilin and promoted ß-catenin activation. Pharmacological inhibition of CD73 adenosinergic signaling was found to induce RICS dysfunction. Dissemination and hematogenous metastasis model showed that targeting CD73 in gastric cancer could suppress experimental metastasis. To conclude, it substantiates CD73 as a target for treatment of gastric cancer metastasis and verifies RICS as an intracellular functional molecule linking CD73/adenosinergic signaling switching to RhoA/LIMK/cofilin pathway.

Crebanine N-oxide, a natural aporphine alkaloid isolated from Stephania hainanensis, induces apoptosis and autophagy in human gastric cancer SGC-7901 cells

Objective: To investigate the cytotoxic effects and the potential mechanisms of crebanine N-oxide in SGC-7901 gastric adenocarcinoma cells. Methods: The cytotoxicity of crebanine N-oxide was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay and cellular morphology was observed under a microscope. Cell apoptosis was determined by flow cytometry using propidium iodide staining. The expression levels of apoptotic-related proteins, cleaved caspase-3, cytochrome C, p53 and Bax, and autophagyrelated proteins p62, beclin1 and LC3 were detected by Western blotting assays. Results: Crebanine N-oxide treatment significantly inhibited the proliferation of SGC-7901 cells in a dose-dependent and timedependent manner via induction of G2-phase cell cycle arrest, apoptosis, and autophagy in SGC-7901 cells. Conclusions: Crebanine N-oxide could inhibit the growth of gastric cancer cells by promoting apoptosis and autophagy and could be used as a potential agent for treating gastric cancer.

High expression of COL10A1 is associated with poor prognosis in colorectal cancer.

BACKGROUND: High expression of collagen type X alpha 1 chain (COL10A1), a member of the collagen family, had been observed in various human cancers, but the detailed function and molecular mechanism of COL10A1 were largely unclear. AIM: The aim of this study was to investigate the expression of COL10A1 in colorectal cancer (CRC) tissues and cells and to reveal its biological function and mechanism in CRC. MATERIALS AND METHODS: Immunohistochemistry (IHC), real-time quantitative polymerase chain reaction (QPCR) and Western blot experiments were used to determine the clinical relevance between expression levels of COL10A1 and CRC. RESULTS: Compared with normal tissues, COL10A1 expression was significantly higher in CRC tissues. Biological functional experiments showed that overexpression of COL10A1 enhanced proliferation, migration, and invasion of CRC cells, and knockdown of COL10A1 inhibited tumorigenesis in vivo. Western blot assays showed that COL10A1 promoted the process of epithelial-mesenchymal transition (EMT). The overexpression of COL10A1 was associated with adverse prognosis in CRC by tissue microarray (TMA) analysis. CONCLUSION: Our findings had provided evidences to support the fact that COL10A1 was abnormally up-expressed in CRC and involved in the progression of CRC and the process of EMT. Furthermore, we demonstrated that the high-level expression of COL10A1 was an independent risk factor of prognosis and overall survival in CRC patients. These suggested that COL10A1 might be a new potential target for cancer therapy in the future.

ImmunoScore Signature: A Prognostic and Predictive Tool in Gastric Cancer.

OBJECTIVE: We postulated that the ImmunoScore (IS) could markedly improve the prediction of postsurgical survival and chemotherapeutic benefits in gastric cancer (GC). SUMMARY BACKGROUND DATA: A prediction model for GC patients was developed using data from 879 consecutive patients. METHODS: The expression of 27 immune features was detected in 251 specimens by using immunohistochemistry, and a 5-feature-based ISGC was then constructed using the LASSO Cox regression model. Testing and validation cohorts were included to validate the model. RESULTS: Using the LASSO model, we established an ISGC classifier based on 5 features: CD3invasive margin (IM), CD3center of tumor (CT), CD8IM, CD45ROCT, and CD66bIM. Significant differences were found between the high-ISGC and low-ISGC patients in the training cohort in 5-year disease-free survival (45.0% vs. 4.4%, respectively; P <0.001) and 5-year overall survival (48.8% vs. 6.7%, respectively; P <0.001). Multivariate analysis revealed that the ISGC classifier was an independent prognostic factor. A combination of ISGC and tumor, node, and metastasis (TNM) had better prognostic value than TNM stage alone. Further analysis revealed that stage II and III GC patients with high-ISGC exhibited a favorable response to adjuvant chemotherapy. Finally, we constructed 2 nomograms to predict which patients with stages II and III GC might benefit from adjuvant chemotherapy after surgery. CONCLUSIONS: The ISGC classifier could effectively predict recurrence and survival of GC, and complemented the prognostic value of the TNM staging system. Moreover, the ISGC might be a useful predictive tool to identify stage II and III GC patients who would benefit from adjuvant chemotherapy.

Erratum: MicroRNA-647 targets SRF-MYH9 axis to suppress invasion and metastasis of gastric cancer: Erratum.

[This corrects the article DOI: 10.7150/thno.20512.].

MicroRNA-647 Targets SRF-MYH9 Axis to Suppress Invasion and Metastasis of Gastric Cancer.

MicroRNAs (miRNAs) play important roles in regulating tumour development and progression. Here we show that miR-647 is repressed in gastric cancer (GC), and associated with GC metastasis. Moreover, we identify that miR-647 can suppress GC cell migration and invasion in vitro. Mechanistically, we confirm miR-647 directly binds to the 3' untranslated regions of SRF mRNA, and SRF binds to the CArG box located at the MYH9 promoter. CCG-1423, an inhibitor of RhoA/SRF-mediated gene transcription, inhibits the expression of MYH9, especially in SRF downregulated cells. Overexpression of miR-647 inhibits MGC 80-3 cells' metastasis in orthotropic GC models, but increasing SRF expression in these cells reverses this change. Importantly, we found the synergistic inhibition effect of CCG-1423 and agomir-647, an engineered miRNA mimic, on cancer metastasis in orthotropic GC models. Our study demonstrates that miR-647 functions as a tumor metastasis suppressor in GC by targeting SRF/MYH9 axis.

[TALEN-mediated MYH9 Knock-down and its influence on cell cycle and apoptosis of MGC803 cell line].

OBJECTIVE: To construct a MYH9 gene knockout model in MGC803 cell line using transcription activator-like effector nuclease (TALEN) and observe its effect on cell cycle and apoptosis. METHODS: According to FastTALE(TM) TALEN Kit, we designed TALEN pairs and constructed the plasmids targeting to MYH9 gene. After detecting their activity in MGC803 cells by plasmid transfection, DNA sequencing, RT-PCR and western blot, we selected the monoclonal cells and studied the changes in the cell cycle and apoptosis. RESULTS: MYH9 gene could not be knocked out but knocked down in selected MGC803 monoclonal cells, which caused cell cycle arrested at G2/M phase (P<0.05) and a significant increase in the cell number with early apoptosis (P<0.01). CONCLUSION: We successfully generated a MYH9 knockdown model in MGC803 cell lines by TALEN, which could be in favor of MYH9 function study in gastric cancer.

SP1-mediated microRNA-520d-5p suppresses tumor growth and metastasis in colorectal cancer by targeting CTHRC1.

Recent evidence suggests that miR-520 family has an important role in regulating tumorigenesis and development of various types of solid cancers. However, as one of the most common cancers in the world, there is little known about the underlying regulatory mechanisms of miR-520 in colorectal cancer (CRC). In the present study, we investigated the expression of microRNA-520d-5p (miR-520d-5p) in CRC specimens and then explored its potential role and mechanism in CRC progression. We found that miR-520d-5p was markedly down-regulated in CRC clinical specimens compared with adjacent normal tissues by real-time PCR. Dual-luciferase assays confirmed that miR-520d-5p directly targeting CTHRC1 and SP1 transactivate miR-520d-5p by binding to its upstream promoter region. The biological functional experiments showed that ectopic re-expression of miR-520d-5p suppressed CRC cell proliferation, migration and invasion, whereas the inhibition of miR-520d-5p displayed an inverse effect in vitro and in vivo. Western blot shown that miR-520d-5p abrogated the epithelial-mesenchymal transition by inactivating the phosphorylation of Erk1/2. In conclusion, our findings indicate that miR-520d-5p is significantly down-expressed and involved in CRC progression and metastasis by targeting CTHRC1 and regulated by SP1, which provide new support for miR-520d-5p maybe as a novel anti-onco molecular target for the treatment of CRC in the future.

[Role of CTHRC1 in proliferation, migration and invasion of human colorectal cancer cells].

OBJECTIVE: To explore the expression of collagen triple helix repeat containing 1 (CTHRC1) in colorectal cancer and study its role in regulating the biological behaviors of colorectal cancer LoVo cells in vitro. METHODS: Real-time PCR and Western blotting were used to detect the expressions of CTHRC1 in colorectal cancer tissue and paired adjacent nontumorous tissue and in 5 colorectal cancer cells. pGPU6-CTHRC1-shRNA was transfected into LoVo cells and the changes in cell proliferation was assessed using cell counting kit-8 (CCK8) assay; the changes in cell migration and invasion were investigated using Transwell assay; plate colony forming test was used to evaluate the adhesion and colony forming activity of the cells. Western blotting was used to analyze the changes in the expressions of the related pathway markers. RESULTS: The relative expression of CTHRC1 mRNA in the cancer tissue specimens was 0.0411∓0.054, significantly higher than that in the adjacent tissues (P=0.016); this result was consistent with that of the protein assay. SW620 and LoVo cells showed obviously higher expressions of CTHRC1 than HT29 and SW480 cells at both mRNA and protein levels. LoVo cells transfected with CTHRC1 shRNA exhibited significantly suppressed proliferation, migration, invasion and colony-forming ability (P<0.05) and lowered expression of phosphorylated ERK1/2 (P-ERK1/2), but the expression of total ERK1/2 showed no obvious changes. CTHRC1 inhibition caused reverse epithelial-mesenchymal transition LoVo cells shown by increased E-cadherin expression and decreased expressions of N-cadherin, vimentin, and ß-catenin. CONCLUSION: CTHRC1 is up-regulated in colorectal cancer tissues and SW620 and LoVo cells to promote the cell proliferation, migration, invasion and colony formation. CTHRC1 can enhance epithelial-mesenchymal transition of colorectal cancer cells by activating ERK1/2 to promote tumor cell metastasis and invasion.

Identification of the interplay between SOX9 and S100P in the metastasis and invasion of colon carcinoma.

Elevated expression of S100P has been detected in several tumor types and suggested to be responsible for tumor metastasis and invasion, but the upstream regulatory mechanisms promoting S100P overexpression are largely unknown. Here, we report that SOX9 was predicted and verified as a transcription factor of S100P. SOX9 and S100P were both overexpressed in colon cancer. SOX9 bound to and activated the S100P promoter. Knockdown of SOX9 expression down-regulated S100P expression, resulting in reduced invasiveness and metastasis of colon cancer cells by inhibiting the activation of receptor for advanced glycation end products (RAGE)/ERK signaling and epithelial-mesenchymal transition (EMT). Further, decreased expression of SOX9 dramatically inhibited the tumor growth and peritoneal metastasis in nude mice. More importantly, S100P was found to be critical for SOX9-mediated metastasis and invasion in colon cancer. Knockdown of S100P in SOX9-overexpressing colon cancer cells dramatically suppressed metastasis and invasion both in vitro and in mice. We also detected SOX9 and S100P expression in a tissue microarray with 90 colon cancer cases to provide their clinical relevance. There was a strong correlation between SOX9 and S100P expression in colon carcinomas. In conclusion, our results suggest that SOX9 promotes tumor metastasis and invasion through regulation of S100P expression.

Overexpression of the Receptor for Advanced Glycation Endproducts (RAGE) is associated with poor prognosis in gastric cancer.

BACKGROUND: The receptor for advanced glycation endproducts (RAGE) is an oncogenic multidisciplinary trans-membranous receptor, which is overexpressed in multiple human cancers. Recently, it has been shown that RAGE is also involved in carcinogenesis and tumor invasion. In this study, we investigated the expression levels and prognostic value of RAGE in primary gastric cancers (GC). METHODS: We investigated RAGE expression in primary GC and paired normal gastric tissue by real-time quantitative RT-PCR (n = 30) and Western blotting analysis (n = 30). Additionally, we performed immunohistochemistry on 180 paraffin-embedded GC specimens, 69 matched normal specimens. RESULTS: RAGE was overexpressed in GC compared with the adjacent noncancerous tissues (P＜0.001), and higher RAGE expression significantly correlated with the histological grade (P = 0.002), nodal status(P = 0.025), metastasis status(P = 0.002), and American Joint Committee on Cancer stage (P = 0.020). Furthermore, upregulation of RAGE expression is an independent prognostic factor in multivariate analysis using the Cox regression model (P = 0.001). CONCLUSIONS: RAGE Overexpression may be a useful marker to predict GC progression and poor prognosis.

miR-574-5p negatively regulates Qki6/7 to impact ß-catenin/Wnt signalling and the development of colorectal cancer.

OBJECTIVE: Deficiency or reduced expression of signal transduction and activation of RNA family protein Quaking (Qki) is associated with developmental defects in neural and vascular tissues and the development of debilitating human diseases including colorectal cancer (CRC). However, the mechanisms underlying the aberrant downregulation or deficiency of Qki were uncertain. DESIGN: Expression of miR-574-5p, Qki5/6/7/7b splicing variants, ß-catenin and p27(Kip1) was determined in mouse and human CRC cells and tissues to investigate the post-transcriptional regulation of Qki isoforms by miR-574-5p and its impact on ß-catenin/p27(Kip1) signalling, cell cycle progression, proliferation, migration, invasion and tumour growth. RESULTS: In the CRC tissues of C57BL/6-Apc(min/+) mice, miR-574-5p was found to be significantly upregulated and negatively correlated with the expression of Qki but positively correlated with the expression of ß-catenin. In mouse and human CRC cells, miR-574-5p was shown to regulate Qki isoforms (Qki6/7 in particular) post-transcriptionally and caused altered expression in ß-catenin and p27(Kip1) , increased proliferation, migration and invasion and decreased differentiation and cell cycle exit. Furthermore, in clinical CRC tissues, miR-574-5p was shown to be greatly upregulated and inversely correlated with the expression of Qkis. Finally, inhibition of miR-574-5p was shown to suppress the growth of tumours in the nude mice. CONCLUSIONS: Together, these novel findings suggest that miR-574-5p is a potent ribo-regulator for Qkis and that aberrant miR-574-5p upregulation can be oncogenic.