Differentiated embryonic chondrocyte-expressed gene 1 is associated with hypoxia-inducible factor 1α and Ki67 in human gastric cancer

HIF1A protein expression is correlated with clinical features in gastric cancer: an updated systematic review and meta-analysis

To elucidate the correlation of HIF1A with clinicopathologic characteristics in patients with gastric cancer (GC), we conducted a systematic review and meta-analysis. We searched PubMed, Embase and Web of Science for studies on GC and HIF1A, covering studies published until January 31st, 2022. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for clinical characteristics based on high and low HIF1A protein levels. We used random-effects and fixed-effects meta-analysis methods to determine mean effect sizes of ORs and evaluated publication heterogeneity with τ2, I2, and Q values. Additionally, we generated funnel plots to inspect publication bias. Our meta-analysis included 20 publications with 3416 GC patients to estimate the association between high or low HIF1A expression and clinical characteristics. Positive HIF1A expression was significantly associated with T stage progression (OR: 2.46; 95% CI 1.81-3.36; P < 0.01), TNM stage progression (OR: 2.50; 95% CI 1.61-3.87; P < 0.01), lymph node metastasis (OR: 2.06; 95% CI 1.44-2.94; P < 0.01), undifferentiated status (OR: 1.83; 95% CI 1.45-2.32; P < 0.01), M stage progression (OR: 2.34; 95% CI 1.46-3.77; P < 0.01), Borrmann stage progression (OR: 1.48; 95% CI 1.02-2.15; P = 0.04), larger tumor size (OR: 1.27; 95% CI 1.06-1.52; P < 0.01), vascular invasion (OR: 1.94; 95% CI 1.38-2.72; P < 0.01), and higher vascular endothelial growth factor (VEGF) protein expression (OR: 2.61; 95% CI 1.79-3.80; P < 0.01) in our meta-analysis. GC Patients highly expressing HIF1A protein might be prone to tumor progression, poorly differentiated GC cell types, and a high VEGF expression.

LncRNA H19 Influences Cellular Activities via the miR-454-3p/BHLHE40 Axis in Anaplastic Thyroid Carcinoma

Anaplastic thyroid carcinoma (ATC) is an aggressive malignancy threatening patients' life quality. Our previous study has demonstrated that inhibition of long non-coding RNA H19 (lncRNA h19; H19) blocks ATC growth and metastasis. The current study aimed to further explore the potential mechanism of H19 in ATC. Expression of H19, miR-454-3p, and BHLHE40 mRNA was measured using RT-qPCR in tissue samples and cell lines. The dual-luciferase reporter assay and Pearson correlation analysis were used to explore the interaction among H19, miR-454-3p, and BHLHE40. The biological process of proliferation, migration, and invasion was determined using loss- or gain-function CCK-8 and Transwell assays. Western blot assay was used to evaluate the changes in protein levels. H19 was elevated in ATC tissues and cell lines. Based on online prediction database results, miR-454-3p might be a target of H19, and BHLHE40 might be a direct target of miR-454-3p. miR-454-3p expression was decreased in ATC and had a negative interaction with H19. BHLHE40 mRNA expression was increased and has a negative correlation with miR-454-3p and a positive correlation with H19. Downregulation of miR-454-3p and upregulation of BHLHE40 could reverse the decreased cellular activities caused by si-H19. Moreover, the silence of H19 modulates BHLHE40 to affect the PI3K/AKT protein levels and apoptotic-related protein levels. The current study provided a potential detailed mechanism of H19 in ATC, and lncRNA H19-miR-454-3p-BHLHE40 interaction may be a new experimental basis for prognosis and targeted therapy for ATC patients.

DEC1 is involved in TGF-β1-induced epithelial-mesenchymal transition of gastric cancer

DEC1 is a helix-loop-helix (bHLH) transcription factor, whose deregulation has been observed in several tumors. However, the effects of the dysregulation of this gene on epithelial-mesenchymal transition (EMT) are controversial, with its roles in gastric cancer (GC) remaining unclear. In the present study, we focused on the impact of DEC1 on EMT and cell mobility in gastric cancer. We found that DEC1 expression positively correlated with TGF-β1 and EMT markers in tumor issues, and that DEC1 facilitated TGF-β1-induced EMT in gastric cancer. In addition, gastric cancer cell migration potential was reduced after DEC1 knockdown. Using murine metastasis models, we confirmed that DEC1 promoted GC metastasis and further explored the correlation of DEC1 with TGF-β1 and E-cadherin in vivo. Chromatin immunoprecipitation (ChIP) assays revealed that DEC1 could directly interact with the promoter region of TGF-β1. These results suggest that DEC1 functions as a tumor enhancer that partially participates in TGF-β1-mediated EMT processes in GC, thus contributing to tumor metastasis.

BHLHE40 Maintains the Stemness of PαS Cells In Vitro by Targeting Zbp1 through the Wnt/β-Catenin Signaling Pathway

Primary bone mesenchymal stem cells (BMSCs) gradually lose stemness during in vitro expansion, which significantly affects the cell therapeutic effects. Here, we chose murine PαS (SCA-1+PDGFRα+CD45-TER119-) cells as representative of BMSCs and aimed to explore the premium culture conditions for PαS cells. Freshly isolated (fresh) PαS cells were obtained from the limbs of C57/6N mice by fluorescence-activated cell sorting (FACS). We investigated the differences in the stemness of PαS cells by proliferation, differentiation, and stemness markers in vitro and by ectopic osteogenesis and chondrogenesis ability in vivo, as well as the changes in the stemness of PαS cells during expansion in vitro. Gain- and loss-of-function experiments were applied to investigate the critical role and underlying mechanism of the basic helix-loop-helix family member E40 (BHLHE40) in maintaining the stemness of PαS cells. The stemness of fresh PαS cells representative in vivo was superior to that of passage 0 (P0) PαS cells in vitro. The stemness of PαS cells in vitro decreased gradually from P0 to passage 4 (P4). Moreover, BHLHE40 plays a critical role in regulating the stemness of PαS cells during in vitro expansion. Mechanically, BHLHE40 regulates the stemness of PαS cells by targeting Zbp1 through the Wnt/β-catenin signaling pathway. This work confirms that BHLHE40 is a critical factor for regulating the stemness of PαS cells during expansion in vitro and may provide significant indications in the exploration of premium culture conditions for PαS cells.

Ki67 for evaluating the prognosis of gastrointestinal stromal tumors: A systematic review and meta‑analysis

Overexpression of Ki67 is observed in tumor cells, and it has been suggested to be a marker for cancer prognosis. However, the relationship between Ki67 expression and the risk of recurrence of gastrointestinal stromal tumors (GISTs) remains poorly defined. In the present study, a meta-analysis was used to examine the associations between Ki67 levels and GIST recurrence. Studies reporting GIST and Ki67 were found by searching Cochrane Library, PubMed and Embase until October 14, 2021. The Newcastle-Ottawa Scale (NOS) was used to verify the quality of the evidence. Totally, 1682 patient cases were included. The odds ratio (OR) estimates and 95% confidence interval (CI) for each publication were determined by a fixed-effects (Mantel-Haenszel) model. A total of 20 studies that fulfilled the inclusion criteria were finally included in the analysis. The average score of quality evaluation was 6.4 points according to NOS. It was found that Ki67 levels were significantly higher in the NIH L group compared with the NIH VL group (OR: 0.51; 95% CI: 0.26-0.99; P=0.04; P heterogeneity=0.44). There was also greater Ki67 overexpression in the NIH I group compared with the NIH L group (OR: 0.45, 95% CI: 0.31-0.65; P<0.0001; P heterogeneity=0.32), while Ki67 levels were greater in the NIH H group than in the NIH I group (OR: 0.20; 95% CI: 0.15-0.28; P<0.00001; P heterogeneity=0.56). In conclusion, Ki67 overexpression may be a useful marker of the risk of recurrent GIST transformation.

Reciprocal Expression of Differentiated Embryonic Chondrocyte Expressed Genes Result in Functional Antagonism in Gastric Cancer

BACKGROUND

Differentiated embryonic chondrocyte expressed genes (DECs) are critical regulators of cellular proliferation and differentiation. However, DEC1 and DEC2 as family member have opposite or identical roles in tumor, acting as an "accelerator" or a "brake" in progression.

AIMS

The possible crosstalk between DEC1 and DEC2 in the gastric cancer (GC).

METHODS

The association of DEC1 and DEC2 expression with prognosis was investigated by immunohistochemistry. The expression pattern of DECs in GC cells was examined using the CCLE database. DECs knockdown or overexpression was conducted via lentiviral transfection. The proliferation of GC cells was evaluated by CCK8, EdU, and Colony forming. ChIP and luciferase reporter assays were used to verify interaction between DEC1 and the DEC2 promoter. The combination downstream with DEC1 and DEC2 was predicted by bioinformation, with Western blot providing further verification.

RESULTS

We found that reciprocal expression of DEC1 and DEC2 works together to sustain the progression of GC by promoting cell growth. We confirmed this observation in vivo, showing that inhibition DEC1expression could increase DEC2 expression. DEC1 suppresses DEC2 expression by directly binding to the E-box of the DEC2 promoter in GC cells. Furthermore, this regulation of DEC1 on DEC2 enables the further indirect or cooperative activation of additional downstream target genes, MAPK, and STAT3.

CONCLUSION

Our data demonstrate that DEC1 and DEC2 interact physically and functionally and identify a novel mode of cross-regulatory interaction between DECs that abrogates their functional activity.

DEC1 promotes progression of Helicobacter pylori-positive gastric cancer by regulating Akt/NF-κB pathway

Helicobacter pylori (H. pylori) infection plays a crucial role in the initiation and progression of gastric cancer (GC). Differentiated embryo‐chondrocyte expressed gene 1 (DEC1) is dysregulated in some cancers and may regulate cell proliferation in specific contexts. Of note, DEC1 is emerging as one of the important factors regulating cellular responses in microenvironment. However, the triggers and precise regulation mechanism for DEC1 during inflammatory carcinoma transformation of GC are unclear. In this study, we identified DEC1 was upregulated in both H. pylori‐infected gastric tissues and GC cells. DEC1 expression was positively associated with H. pylori infection status and GC progression. DEC1‐positive expression indicated a poorer prognosis in H. pylori‐positive GC. DEC1 was required for H. pylori‐induced GC cells proliferation. Mechanistically, H. pylori infection significantly activated Akt/NF‐κB signal pathway and this induction depend on DEC1 expression level in GC cells. Importantly, their interaction pathway was further verified by H. pylori‐positive gastritis mice model. Taken together, our findings identified a novel function of DEC1 in GC. H. pylori infection induce DEC1 expression, and which leading to the progression of GC through activating Akt/ NF‐κB signalling pathway. Blocking DEC1/Akt/NF‐κB, therefore, presents a promising novel therapeutic strategy for H. pylori‐positive GC.

Differentiated embryo chondrocyte 1, induced by hypoxia-inducible factor 1α, promotes cell migration in oral squamous cell carcinoma cell lines

OBJECTIVE

This study aimed to explore the correlation between differentiated embryo chondrocyte 1 (DEC1) and hypoxia-inducible factor 1α (HIF-1α) in oral squamous cell carcinoma (OSCC) and how they participate in tumor progression.

STUDY DESIGN

An immunohistochemical staining method was used to detect the expression of HIF-1α and DEC1 in 64 OSCC specimens, and the correlation between HIF-1α and DEC1 was analyzed. The expression of HIF-1α and DEC1 in OSCC cells under normoxic and hypoxic environments was assessed and analyzed by Western blotting and immunofluorescence. Furthermore, the DEC1 gene was silenced by siRNA and treated with cobalt chloride (CoCl₂) to analyze the effects that DEC1 and hypoxia might have on the migration ability of OSCC cells.

RESULTS

The expression of HIF-1α and DEC1 in OSCC was positively correlated. Using CoCl₂ to simulate a hypoxic environment increased the protein levels of HIF-1α and DEC1 in OSCC cells. The HIF-1α inhibitor LW6 decreased HIF-1α and DEC1 expression in OSCC cells in a hypoxic environment. Silencing the DEC1 gene reduced the migration ability of OSCC cells.

CONCLUSION

The hypoxic environment in OSCC could upregulate the expression of DEC1 by increasing the protein level of HIF-1α, and this process might be involved in the migration of tumor cells.

Hypoxia-induced DEC1 mediates trophoblast cell proliferation and migration via HIF1α signaling pathway

In early pregnancy, hypoxia is a typical extrinsic factor that regulates EVT functions including proliferation, migration and invasion which are essential for a successful pregnancy. Human differentiated embryonic chondrocyte-expressed gene 1 (DEC1), a hypoxia-regulated gene, has been reported to be overexpressed in several types of cancers. Given that the placenta and the cancer share several similarities with respect to their capacity to proliferate and invade adjacent tissues, we focused on the role of DEC1 on trophoblast function in a physiologically hypoxic environment, which may be associated with unexplained recurrent spontaneous abortion (URSA).In our study, we measured the expression of HIF-1α and DEC1 in first-trimester villi through real-time-PCR (RT-PCR) and immunohistochemical analysis. in vitro, DEC1 expression was downregulated in trophoblast cells via DEC1-specific shRNA plasmid transfection. The expression of DEC1 and HIF-1α was detected via western blotting and RT-PCR analysis. The proliferation and migration of HTR-8/SVneo cells were assayed using CCK-8 and Transwell migration assays, respectively.Our results indicated that the expression of DEC1 was significantly reduced in villi of URSA compared to that in normal pregnant women. in vitro, hypoxia induced the expression of HIF-1ɑ and DEC1 and upregulated proliferation and migration of the HTR-8/SVneo cells. Knockdown of DEC1 inhibited proliferation and migration of HTR-8/SVneo cells exposure to hypoxia. Furthermore, inhibition of HIF1α expression resulted in a significant decrease in DEC1. These findings illustrate that hypoxia-induced DEC1 expression promotes trophoblast cell proliferation and migration through the HIF1α signaling pathway, which plays an important role during placentation.

Identification of BHLHE40 expression in peripheral blood mononuclear cells as a novel biomarker for diagnosis and prognosis of hepatocellular carcinoma

Novel and sensitive biomarkers is highly required for early detection and predicting prognosis of hepatocellular carcinoma (HCC). Here, we investigated transcription profiles from peripheral blood mononuclear cells (PBMCs) of 8 patients with HCC and PBMCs from co-culture model with HCC using RNA-Sequencing. These transcription profiles were cross compared with published microarray datasets of PBMCs in HCC to identify differentially expressed genes (DEGs). A total of commonly identified of 24 DEGs among these data were proposed as cancer-induced genes in PBMCs, including 18 upregulated and 6 downregulated DEGs. The KEGG pathway showed that these enriched genes were mainly associated with immune responses. Five up-regulated candidate genes including BHLHE40, AREG, SOCS1, CCL5, and DDIT4 were selected and further validated in PBMCs of 100 patients with HBV-related HCC, 100 patients with chronic HBV infection and 100 healthy controls. Based on ROC analysis, BHLHE40 and DDIT4 displayed better diagnostic performance than alpha-fetoprotein (AFP) in discriminating HCC from controls. Additionally, BHLHE40 and DDIT4 had high sensitivity for detecting AFP-negative and early-stage HCC. BHLHE40 was also emerged as an independent prognostic factor of overall survival of HCC. Together, our study indicated that BHLHE40 in PBMCs could be a promising diagnostic and prognostic biomarker for HBV-related HCC.

A Systematic Review of the Mechanisms Underlying Treatment of Gastric Precancerous Lesions by Traditional Chinese Medicine

Gastric precancerous lesions (GPLs) are an essential precursor in the occurrence and development of gastric cancer, known to be one of the most common and lethal cancers worldwide. Traditional Chinese medicine (TCM) has a positive prospect for the prevention and therapy of GPL owing to several advantages including a definite curative effect, fewer side effects compared to other treatments, multiple components, and holistic regulation. Despite these characteristic advantages, the mechanisms of TCM in treating GPL have not been fully elucidated. In this review, we summarize the current knowledge with respect to herbal formulations and the therapeutic mechanisms of TCM active ingredients for GPL. This paper elaborates on the mechanisms of TCM underlying the prevention and treatment of GPL, specifically those that are linked to anti-H. pylori, anti-inflammation, antiproliferation, proapoptotic, antioxidation, antiglycolytic, and antiangiogenesis effects.

Potential Role of DEC1 in Cervical Cancer Cells Involving Overexpression and Apoptosis

Basic helix-loop-helix (BHLH) transcription factors differentiated embryonic chondrocyte gene 1 (DEC1) and gene 2 (DEC2) regulate circadian rhythms, apoptosis, epithelial mesenchymal transition (EMT), invasions and metastases in various kinds of cancer. The stem cell markers SOX2 and c-MYC are involved in the regulation of apoptosis and poor prognosis. In cervical cancer, however, their roles are not well elucidated yet. To determine the function of these genes in human cervical cancer, we examined the expression of DEC1, DEC2, SOX2 and c-MYC in human cervical cancer tissues. In immunohistochemistry, they were strongly expressed in cancer cells compared with in non-cancerous cells. Notably, the strong rate of DEC1 and SOX2 expressions were over 80% among 20 cases. We further examined the roles of DEC1 and DEC2 in apoptosis. Human cervical cancer HeLa and SiHa cells were treated with cisplatin-HeLa cells were sensitive to apoptosis, but SiHa cells were resistant. DEC1 expression decreased in the cisplatin-treated HeLa cells, but had little effect on SiHa cells. Combination treatment of DEC1 overexpression and cisplatin inhibited apoptosis and affected SOX2 and c-MYC expressions in HeLa cells. Meanwhile, DEC2 overexpression had little effect on apoptosis and on SOX2 and c-MYC expressions. We conclude that DEC1 has anti-apoptotic effects and regulates SOX2 and c-MYC expressions on apoptosis.

Effect of DEC1 on the proliferation, adhesion, invasion and epithelial-mesenchymal transition of osteosarcoma cells

Differentiated embryonic chondrocyte-expressed gene 1 (DEC1) is associated with various types of human cancer; however, there is limited data regarding the functions of DEC1 in osteosarcoma. The present study aimed to examine the expression of DEC1 in human osteosarcoma tissues and cell lines. Furthermore, the effects of DEC1 on the proliferation, adhesion, invasion and epithelial-mesenchymal transition (EMT) of osteosarcoma cells were investigated. Using reverse transcription-quantitative PCR and western blot analysis, it was found that the expression levels of DEC1 were higher in human osteosarcoma tissues and osteosarcoma cell lines than in the controls. Both gain- and loss-of-function experiments suggested that DEC1 promotes the proliferation, adhesion and invasion of osteosarcoma cells in vitro, as determined by MTT, cell adhesion and cell invasion assays, respectively. Additionally, DEC1 was found to upregulate the mesenchymal markers N-cadherin and vimentin, whilst downregulating the epithelial marker E-cadherin. In conclusion, this present study showed increased expression levels of DEC1 in human osteosarcoma tissues and cell lines, and identified that DEC1 may exert its effect on osteosarcoma progression by promoting cell proliferation, adhesion and invasion. Furthermore, DEC1 was shown to have an inducible effect on EMT in osteosarcoma cell lines, thus contributing to the aggressiveness of osteosarcoma cells. This initial study indicated that DEC1 may serve as a novel molecular target for the treatment of osteosarcoma.

Non-circadian aspects of BHLHE40 cellular function in cancer

While many genes specifically act as oncogenes or tumor suppressors, others are tumor promoters or suppressors in a context-dependent manner. Here we will review the basic-helix-loop-helix (BHLH) protein BHLHE40, (also known as BHLHB2, STRA13, DEC1, or SHARP2) which is overexpressed in gastric, breast, and brain tumors; and downregulated in colorectal, esophageal, pancreatic and lung cancer. As a transcription factor, BHLHE40 is expressed in the nucleus, where it binds to target gene promoters containing the E-box hexanucleotide sequence, but can also be expressed in the cytoplasm, where it stabilizes cyclin E, preventing cyclin E-mediated DNA replication and cell cycle progression. In different organs BHLHE40 regulates different targets; hence may have different impacts on tumorigenesis. BHLHE40 promotes PI3K/Akt/mTOR activation in breast cancer, activating tumor progression, but suppresses STAT1 expression in clear cell carcinoma, triggering tumor suppression. Target specificity likely depends on cooperation with other transcription factors. BHLHE40 is activated in lung and esophageal carcinoma by the tumor suppressor p53 inducing senescence and suppressing tumor growth, but is also activated under hypoxic conditions by HIF-1α in gastric cancer and hepatocellular carcinomas, stimulating tumor progression. Thus, BHLHE40 is a multi-functional protein that mediates the promotion or suppression of cancer in a context dependent manner.

Weiqi Decoction Attenuated Chronic Atrophic Gastritis with Precancerous Lesion through Regulating Microcirculation Disturbance and HIF-1α Signaling Pathway

Aim

Chronic atrophic gastritis (CAG), the precancerous lesions of gastric cancer, plays an important role in the stepwise process of gastric cancer. The ancient Chinese medicine believes in that Qi deficiency and blood stasis are involved in the pathogenesis of CAG. Weiqi decoction, a classical formula from Longhua Hospital, could supplement Qi and activate blood circulation of human beings and has been used for treating CAG in clinic over twenty years. The study aims to clarify the effect and underlying molecular mechanism of Weiqi decoction on CAG rats.

Methods

Forty-eight male Wistar rats were divided randomly into six groups: control group, model group, folic acid group, and WQD-treated groups at doses of 4 g/kg, 2 g/kg, and 1 g/kg, with eight rats in each group. MNNG and saturated NaCl were used to induce CAG rat with precancerous lesion (intestinal metaplasia and dysplasia). After 40 weeks, gastric mucosal blood flow was measured using Laser Doppler Flowmetry. The pathological changes of the gastric mucosa were identified by H&E staining and AB-PAS staining. The protein expression of COX-2, HIF-1α, VEGFR1, VEGFR2, Ki67, and cleaved caspase 3 in the gastric tissues was measured by western blotting approach. Gene expression of COX-2, HIF-1α, VEGF, VEGFR1, VEGFR2, Ang-1, and Ang-2 was detected by using Quantitative PCR method. The PGE2 concentrations in serum were detected by ELISA method. The protein expression of Ki67 in gastric mucosa was also detected by immunohistochemistry.

Results

Compared with control rats, atrophy and intestinal metaplasia as well as the microcirculation disturbance of gastric mucosa were induced in the stomach of CAG rats identified by the H&E and AB-PAS staining as well as microcirculation measurement, which could be significantly attenuated by WQD treatment. Moreover, compared with the control group, the protein and gene expression of COX-2, HIF-1α, VEGFR1, and VEGFR2 in gastric tissues of pylorus was obviously increased and the serum PGE2 level was significantly deceased in CAG rats, which could be significantly counteracted by WQD administration. However, the gene expression of Ang-1 and Ang-2 was not significant difference between control rats and CAG rats, and WQD also had no significant effect on the gene expression of Ang-1 and Ang-2. Furthermore, the increased cell proliferation marked by upregulated protein expression of Ki67 and decreased cell apoptosis marked by downregulated protein expression of cleaved caspase 3 in stomach of pylorus in CAG rats were obviously reversed by WQD treatment.

Conclusion

WQD attenuated CAG with precancerous lesion through regulating gastric mucosal blood flow disturbance and HIF-1α signaling pathway.

Expression of DEC2 enhances chemosensitivity by inhibiting STAT5A in gastric cancer

Gastric cancer (GC) is one of the most common cancers. Resistance to 5-fluorouracil (5-Fu)-based chemotherapy is a major cause of treatment failure followed by the poor prognosis of patients. In GC, it was reported that human differentiated embryonic chondrocyte-expressed gene 2 (DEC2), suppressed tumor proliferation and metastasis, but the effect of DEC2 on chemosensitivity of GC cells was unknown. In our study, we found that DEC2 can obviously increase the sensibility of GC cells to 5-Fu by promoting 5-Fu-induced apoptosis. DEC2 overexpression is significantly associated with decreased phosphorylation of STAT5A (P-STAT5A). More importantly, negative correlations between DEC2 with P-STAT5A expression were observed in tissue sections from GC patients. GC patients with low expression levels of DEC2 and high expression levels of P-STAT5A showed a poor prognosis. Furthermore, enhanced chemosensitivity mediated by DEC2 can be reversed by STAT5A which confer GC cells resistance to apoptosis induced by 5-Fu. Together, our results suggest that through inhibiting activation of STAT5A, DEC2 enhances 5-Fu-induced apoptosis and suppression of proliferation in GC cells. These findings will provide new insight for identifying potential targets that can be used to sensitize GC cells to chemotherapy.

Proteomic analysis of the effects of cell culture density on the metastasis of breast cancer cells

Cancer cell progression and proliferation increase cell density, resulting in changes to the tumour site, including the microenvironment. What is not known is if increased cell density influences the aggressiveness of cancer cells, especially their proliferation, migration, and invasion capabilities. In this study, we found that dense cell culture enhances the aggressiveness of the metastatic cancer cell lines, 4T1 and ZR-75-30, by increasing their proliferation, migration, and invasion capabilities. However, a less metastatic cell line, MCF-7, did not show an increase in aggressiveness, following dense cell culture conditions. We conducted a differential proteomic analysis on 4T1 cells cultured under dense or sparse conditions and identified an increase in expression for proteins involved in migration, including focal adhesion, cytoskeletal reorganization, and transendothelial migration. In contrast, 4T1 cells grown under sparse conditions had higher expression levels for proteins involved in metabolism, including lipid and phospholipid binding, lipid and cholesterol transporter activity, and protein binding. These results suggest that the high-density tumour microenvironment can cause a change in cellular behaviour, leading towards more aggressive cancers. SIGNIFICANCE OF THE STUDY: Metastasis of cancer cells is an obstacle to the clinical treatment of cancer. We found that dense cultures made metastatic cancer cells more potent in terms of proliferation, migration, and invasion. The proteomic and bioinformatic analyses provided some valuable clues for further intensive studies about the effects of cell density on cancer cell aggressiveness, which were associated with events such as pre-mRNA splicing and RNA transport, focal adhesion and cytoskeleton reorganization, ribosome biogenesis, and transendothelial migration, or associated with proteins, such as JAM-1 and S100A11. This investigation gives us new perspectives to investigate the metastasis mechanisms related to the microenvironment of tumour sites.

DEC1 is required for anti-apoptotic activity of gastric cancer cells under hypoxia by promoting Survivin expression

BACKGROUND

Human differentiated embryonic chondrocyte-expressed gene 1 (DEC1), which has been reported to be overexpressed in several types of cancer, is associated with tumorigenesis through participation in several biological processes. However, the complex mechanisms underlying DEC1 during carcinogenesis are controversial, and its roles in the development and malignancy of gastric cancer (GC) remain unclear.

METHODS

We measured DEC1 expression in human GC cell lines. DEC1 levels in GC cells were downregulated by shRNA lentivirus infection. We also evaluated the effect of DEC1 downregulation on xenograft growth in vivo. The viability and apoptosis of the cells were assayed using the CCK8 assay and flow cytometry. The levels of DEC1, Survivin, and Bcl-2 were evaluated by Western blotting. Luciferase reporter was used to verify the downstream target of DEC1. The association of DEC1 and Survivin expression with prognosis was investigated by immunohistochemistry.

RESULTS

Downregulation of DEC1 inhibits GC cell proliferation in vitro and tumorigenicity in vivo. We observed that hypoxia-induced expression of DEC1 protects GC cells from apoptosis via transcriptional upregulation of Survivin. Furthermore, positive correlations between DEC1 with Survivin expression were observed in tissue sections from GC patients. Notably, GC patients with high expression levels of DEC1 and Survivin showed poor prognosis.

CONCLUSIONS

DEC1 acts as an anti-apoptotic regulator in GC cells under hypoxia by promoting Survivin expression. Our study demonstrates the critical role of the DEC1 in oncogenesis and highlights a novel role for DEC1 in the regulation of cell apoptosis in GC.

Anti-tumor bioactivities of curcumin on mice loaded with gastric carcinoma

Curcumin, a derivative from the dried rhizome of curcuma longa, has been proven to possess anti-tumor effects. However, the detailed molecular mechanisms have not been fully elucidated. In this study, we aimed to explore the anti-tumor mechanisms of curcumin in treating gastric cancer. BALB/C mice grafted with a mouse gastric adenocarcinoma cell line (MFC) were used as the experimental model. Mice received different doses of curcumin after grafting. Tumor size was measured and tumor weight was determined after tumor inoculation. TUNEL assay and flow cytometric analysis were applied to evaluate the apoptosis of the cancer cells. Serum cytokines IFN-γ, TNF-α, granzyme B and perforin were detected by ELISA assay. The anti-tumor effect was determined using cytotoxic T-lymphocyte (CTL) assays and in vivo tumor prevention tests. The expression of DEC1, HIF-1α, STAT3 and VEGF in tumor tissues was examined by immunostaining and analyzed using an Image J analysis system. Compared with controls, tumor growth (size and weight) was significantly inhibited by curcumin treatment (P < 0.05). The apoptotic index in gastric cancer cells was significantly increased in the curcumin treatment group. Splenocyte cells from mice treated with curcumin exhibited higher cytolytic effects on MFC cancer cells than those from mice treated with saline (P < 0.01). The expression of DEC1, HIF-1α, STAT3 and VEGF in tumor tissues was down-regulated after curcumin treatment. Our results indicate that curcumin inhibits the proliferation of gastric carcinoma by inducing the apoptosis of tumor cells, activating immune cells to secrete a large amount of cytokines, and down-regulating the DEC1, HIF-1α, VEGF and STAT3 signal transduction pathways.

Prognostic impact of Ki-67 in patients with gastric cancer-the importance of depth of invasion and histologic differentiation

Ki-67 protein is a cellular marker for proliferation. The role of Ki-67 as a prognostic biomarker has not been established in gastric cancer. The present study was performed to investigate the significance of Ki-67 expression as a biomarker in early gastric cancer (EGC).With tissue microarray for 320 patients with gastric cancer, we performed immunohistochemical staining for Ki-67. Its clinical significance was analyzed with adjustment via the propensity score-matching. For validation, we performed bootstrap resampling.The median follow-up duration was 72 months (range: 3-120 months). Ki-67-high group showed worse prognosis than Ki-67-low group in EGC (5-YSR, 78.9% vs 92.0%, P  =  .018), but not in advanced gastric cancer (AGC) (5-YSR, 58.5% vs 59.2%, P  =  .951). Interestingly, in the patients with well-differentiated histology, prognosis for Ki-67-high group was considerably worse than that for Ki-67-low group (5-YSR, 67.0% vs 94.4%, P  =  .012), but not in those with moderately differentiated (P  =  .504) and poorly differentiated histology (P  =  .905). In this cohort, there was a strong correlation between the proportion of EGC and well-differentiated histology (r  =  0.215, P  =  .002). Multivariate analysis also revealed that the high-Ki-67 expression serves as a poor prognostic factor in EGC (HR 4.346, 95% CI 1.397-13.515, P  =  .011), especially in the well-differentiated histology, but not in all the patients (P  =  .171). Bootstrap resampling internally validated this result (P  =  .011).This study suggests that Ki-67 expression may be a good biomarker for prognosis prediction for EGC with well-differentiated histologic type.

Partial Oxygen Pressure Affects the Expression of Prognostic Biomarkers HIF-1 Alpha, Ki67, and CK20 in the Microenvironment of Colorectal Cancer Tissue

Hypoxia is prognostically important in colorectal cancer (CRC) therapy. Partial oxygen pressure (pO₂) is an important parameter of hypoxia. The correlation between pO₂ levels and expression levels of prognostic biomarkers was measured in CRC tissues. Human CRC tissues were collected and pO₂ levels were measured by OxyLite. Three methods for tissue fixation were compared, including formalin, Finefix, and Finefix-plus-microwave. Immunohistochemistry (IHC) staining was conducted by using the avidin-biotin complex technique for detecting the antibodies to hypoxia inducible factor-1 (HIF-1) alpha, cytokeratin 20 (CK20), and cell proliferation factor Ki67. The levels of pO₂ were negatively associated with the size of CRC tissues. Finefix-plus-microwave fixation has the potential to replace formalin. Additionally, microwave treatment improved Finefix performance in tissue fixation and protein preservation. The percentage of positive cells and gray values of HIF-1 alpha, CK20, and Ki67 were associated with CRC development (P < 0.05). The levels of pO₂ were positively related with the gray values of Ki67 and negatively related with the values of HIF-1 alpha and CK20 (P < 0.05). Thus, the levels of microenvironmental pO₂ affect the expression of predictive biomarkers HIF-1 alpha, CK20, and Ki67 in the development of CRC tissues.

DEC2 suppresses tumor proliferation and metastasis by regulating ERK/NF-κB pathway in gastric cancer

Differentiated embryonic chondrocyte expressed gene 2 (DEC2; BHLHE41/Sharp1) is a helix-loop-helix (bHLH) transcription factor, and its deregulation has been observed in several tumors. However, this gene's effects on tumor progression are controversial, and its roles in gastric cancer (GC) remain unclear. In the present study, we found that DEC2 expression level is lower in GC tissues compared with adjacent non-tumor tissues, and negatively correlated with tumor invasion, lymph node metastasis, TNM stage, and poor survival of GC patients. Positive clinical correlations of DEC2 with EMT regulator, E-cadherin, were also observed in the tissue sections. Overexpression of DEC2 inhibits cell proliferation and EMT in vitro, as well as tumor growth and metastasis in vivo. DEC2 expression also induces cell apoptosis. Furthermore, the anti-metastatic effect of DEC2 was mediated by inhibiting ERK/NF-κB/EMT axis. After treatment with ERK1/2 chemical inhibitor (U0126), DEC2's inhibitory effect on ERK/NF-κB/EMT was further decreased. Collectively, these data helped to characterize DEC2, which might be a potential molecular target for diagnostic and therapeutic approaches for GC.

Decreased LIPF expression is correlated with DGKA and predicts poor outcome of gastric cancer

Gastric cancer (GC) is a common and deadly digestive tract tumor worldwide. Unfortunately, diagnosis of GC is usually confused and misleading because of atypical symptoms or incomplete complaints. Accordingly, exploring gene expression profile and identifying genes with analogical variance trend will bring new perspective into the diagnosis and treatment of GC. Herein, a RNA-Seq dataset from Caucasian GC and their matched non-cancerous samples [Gene Expression Omnibus (GEO): SRP049809] and datasets from four microarrays constituted with tumor and non-tumor tissues (GEO: GSE13911, GSE19826, GSE29272, GSE33335) were analyzed to explore the differentially expressed genes (DGEs). As a result, we identified a core set of 373 DGEs. Among these genes, we found that most downregulated genes were related to lipid-metabolic functions. Especially, the gastric lipase (LIPF) gene, which was connected with various lipid metabolism processes, was significantly decreased among all datasets. We then performed immunohistochemistry experiments using gastric tissue arrays to investigate the clinical effects, and the expression of a LIPF target gene, diacylglycerol kinase α (DGKA). Among the 90 samples of gastric adenocarcinoma, the LIPF and DGKA levels were both decreased in cancer tissues [LIPF, 59.1% (53/90); DGKA, 77.8% (70/90)] compared to normal tissues [LIPF, 94.4% (85/90); DGKA, 90% (81/90)]. The expression level of these two proteins in GC was associated with local invasion and disease stage. Cox regression identified high DGKA expression (HR, 0.49; 95% CI, 0.26–0.94; P=0.03) as a predictor of good prognosis and LNM status (HR, 4.63; 95% CI, 1.39–15.51; P=0.01) as a predictor of poor prognosis. Thus we speculated that LIPF-DGKA might serve as a potential possible biomarkers for diagnosis of GC, and their downregulation may bring new perspective into the investigation of GC prognosis.

DEC1 and DEC2 Crosstalk between Circadian Rhythm and Tumor Progression

Clock genes, major regulators of circadian rhythm, are involved in tumor progression. We have shown that clock genes basic helix-loop-helix (BHLH) transcription factors, differentiated embryonic chondrocyte gene 1 (DEC1/BHLHE40/Sharp2/Stra13) and DEC2 (BHLHE41/Sharp1) play important roles in circadian rhythm, cell proliferation, apoptosis, hypoxia response, various stresses, and epithelial-to-mesenchymal transition (EMT) of tumor cells. Various stresses, such as exposure to transforming growth factor-beta (TGF-β), hypoxia, cytokines, serum-free, and anti-tumor drugs affect DEC1 and DEC2 expression. An increased or decreased expression of DEC1 and DEC2 regulated tumor progression. However, DEC1 and DEC2 have opposite effects in tumor progression, where the reason behind remains unclear. We found that DEC2 has circadian expression in implanted mouse sarcoma cells, suggesting that DEC2 regulates tumor progression under circadian rhythm. In addition to that, we showed that DEC1 and DEC2 regulate target genes via positive or negative feedback system in tumor progression. We propose that DEC1 and DEC2 act as an accelerator or a brake in tumor progression. In this review, we summarize current progress of knowledge in the function of DEC1 and DEC2 genes in tumor progression.

Genetic polymorphisms in hypoxia-inducible factor-1a gene and its association with HBV-related hepatocellular carcinoma in a Chinese population

Previous studies have demonstrated that hypoxia-inducible factor-1a (HIF-1a) may play a vital role in the pathogenesis of hepatocellular carcinoma (HCC). However, the relationship between HIF-1a polymorphisms and HCC has not been thoroughly investigated. The aim of this study is to determine whether HIF-1a polymorphisms are associated with HCC through a case-control study. Two polymorphisms in the HIF-1a gene (rs11549465 and rs115494657) were examined in 157 hepatitis B virus (HBV)-related HCC patients and 173 healthy controls using the polymerase chain reaction-restriction fragment length polymorphism method. DNA sequencing was used to validate genotype results. There were no significant differences in the genotype and allele frequencies of HIF-1a rs11549465 and rs115494657 polymorphisms between the HBV-related HCC patients and healthy controls. However, the data revealed that subjects with the CG haplotype have a higher susceptibility to HBV-related HCC [odds ratio (OR)=2.327, 95% confidence interval (CI)=1.578-4.721, P=0.008]. In contrast, the CA haplotype was associated with a significantly decreased risk of HBV-related HCC (OR=0.416, 95% CI=0.172-0.910, P=0.025). HIF-1a rs11549465 and rs115494657 polymorphisms appeared to be irrelevant to HBV-related HCC. However, the HIF-1a CG and CA haplotypes might be a risk factor and a protective marker, respectively, for HBV-related HCC in a Chinese population. Further investigations with a larger sample size may be required to validate the genetic effects of HIF-1a polymorphisms on HBV-related HCC.

Prognostic significance of the co-expression of nucleophosmin and trefoil factor 3 in postoperative gastric cancer patients

Although a number of studies have indicated that the positive expression of nucleophosmin (NPM) and trefoil factor 3 (TFF3) is associated with oncogenesis and poor prognosis in several tumor types, the prognostic value of the co-expression of NPM and TFF3 in gastric cancer (GC) has not been fully elucidated. Therefore, in this study, we aimed to investigate the role of NPM and TFF3 in GC and determine their prognostic value. We retrospectively reviewed 108 patients who had undergone radical gastric tumor resection. The expression of NPM and TFF3 was detected by immunohistochemistry and the association of NPM and TFF3 with clinicopathological characteristics was investigated using the Chi-square test. Furthermore, univariate and multivariate analyses were conducted to determine the prognostic value of these markers. Of the 108 samples, NPM was positive in 57 (53%) and TFF3 was positive in 54 samples (50%). The positive expression of NPM was correlated with advanced tumor stage and recurrence (P=0.0333 and P<0.0001, respectively), whereas the expression of TFF3 was associated with larger tumor size (P=0.0005), poor differentiation (P=0.0435), lymph node metastasis (P=0.0116), advanced tumor stage (P=0.0244) and recurrence (P=0.0116). The univariate analysis revealed that the expression of NPM, the expression of TFF3 and the co-expression of the two were associated with poor survival (P=0.0004, 0.0028 and 0.0020, respectively). By multivariate analysis, all three factors were identified as independent prognostic factors in postoperative GC patients (hazard ratio = 1.970, 2.021 and 2.339, respectively). In conclusion, the expression of NPM and TFF3 and, particularly, the co-expression of the two, may serve as independent prognostic factors in postoperative GC patients.

Circadian gene variants in cancer

Humans as diurnal beings are active during the day and rest at night. This daily oscillation of behavior and physiology is driven by an endogenous circadian clock not environmental cues. In modern societies, changes in lifestyle have led to a frequent disruption of the endogenous circadian homeostasis leading to increased risk of various diseases including cancer. The clock is operated by the feedback loops of circadian genes and controls daily physiology by coupling cell proliferation and metabolism, DNA damage repair, and apoptosis in peripheral tissues with physical activity, energy homeostasis, immune and neuroendocrine functions at the organismal level. Recent studies have revealed that defects in circadian genes due to targeted gene ablation in animal models or single nucleotide polymorphism, deletion, deregulation and/or epigenetic silencing in humans are closely associated with increased risk of cancer. In addition, disruption of circadian rhythm can disrupt the molecular clock in peripheral tissues in the absence of circadian gene mutations. Circadian disruption has recently been recognized as an independent cancer risk factor. Further study of the mechanism of clock-controlled tumor suppression will have a significant impact on human health by improving the efficiencies of cancer prevention and treatment.

Expression characteristics of CDC20 in gastric cancer and its correlation with poor prognosis

The cell division cycle 20 homolog (CDC20) expression is increased in diverse human cancers and plays a vital role in tumorigenesis and progression. However, the clinical significance of CDC20 expression in gastric cancer (GC) remains largely unknown. The aim of this study was to investigate the clinicopathologic features and prognostic significance of CDC20 in GC. The CDC20 mRNA expression was measured by quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR). Immunohistochemistry (IHC) was used to detect the expression of CDC20 protein in 131 clinicopathologically characterized GC cases. The relationship between CDC20 expression and clinicopathological features was analyzed by appropriate statistics. Kaplan-Meier analysis and Cox proportional hazards regression models were used to investigate the correlation between CDC20 expression and prognosis of GC patients. The relative mRNA expression of CDC20 were significantly higher in GC tumor tissues than in the corresponding noncancerous tissues (P<0.001). Simultaneously, CDC20 protein expression was positively correlated with tumor size (P=0.02), histological grade (P=0.037), lymph node involvement (P=0.009), and TNM stage (P=0.015). Furthermore, Kaplan-Meier analysis indicated that patients with high CDC20 expression had poor overall survival (P<0.001). Multivariate analysis showed that high CDC20 expression was an independent predictor of overall survival. In conclusion, our data indicated that CDC20 upregulation was associated with aggressive progression and poor prognosis in GC. CDC20 was identified for the first time as an independent marker for predicting the clinical outcome of GC patients.

Correlation between gastric HIF-1α expression and gastric cancer recurrence

AIM: To investigate the relationship between hypoxia inducible factor -1α (HIF-1α) expression and gastric cancer recurrence and to analyze factors affecting HIF-1α expression in gastric cancer.

METHODS: Eighty patients with gastric cancer recurrence after radical resection were included in the study, and 50 patients without recurrence after radical resection for more than 5 year were selected as a control group. The expression of HIF-1α and VEGF was compared between the two groups. Risk factors for gastric cancer were analyzed with univariate and Cox proportional hazards models. The correlation between HIF-1α and VEGF expression was investigated by Spearman correlation analysis.

RESULTS: The positive rates of HIF-1α (77.50% vs 12.00%) and VEGF (73.75% vs 10.00%) expression were higher in the recurrence group than in the control group. The degree of differentiation, depth of invasion, lymph node metastasis, vascular invasion, TNM clinical stage, VEGF expression were factors affecting HIF-1α expression in gastric tissue. There was a positive correlation between HIF-1α and VEGF expression (r = 0.458, P = 0.000). The 1-year survival rate (45.16% vs 77.77%) and average survival time (8.62 ± 2.32 vs 18.96 ± 3.14) were significantly lower in the HIF-1α-positive group than in the HIF-1α-negative group. HIF-1α and VEGF expression were independent prognostic factors for gastric cancer.

CONCLUSION: HIF-1α expression is closely related to recurrence of gastric cancer and tumor angiogenesis, and can be used as a parameter for assessing gastric cancer recurrence and prognosis.

Hypoxia-induced overexpression of DEC1 is regulated by HIF-1α in hepatocellular carcinoma

Hypoxia-inducible factor-1α (HIF-1α) and differentiated embryo-chondrocyte expressed gene 1 (DEC1) are two key factors that protect hepatocellular carcinoma (HCC) cells from a hypoxic microenvironment. However, little is known concerning the effects of hypoxia on the expression of HIF-1α and DEC1 in HCC. In the present study, RT-PCR and western blotting were conducted to assay the mRNA and protein levels of HIF-1α and DEC1 under normoxia and hypoxia induced by exposure to CoCl2 for different time periods (0, 2, 4, 6, 24 and 48 h). In addition, the HIF-1α protein inhibitor, YC-1, was used to analyze the interaction between DEC1 and HIF-1α expression and the related mechanism. Results showed that expression of DEC1 in HCC was significantly upregulated at both the mRNA and protein levels, when compared with that in normal liver cells (P<0.05). Hypoxia induced the upregulation of HIF-1α in a time-dependent manner, which was also observed at the DEC1 mRNA and protein levels (P<0.05). However, hypoxia did not affect the transcription of HIF-1α (P>0.05). A positive correlation was found between HIF-1α and DEC1 expression in both BEL-7402 (r=0.885, P<0.05) and SMMC-7721 cells (r=0.826, P<0.05). Furthermore, inhibition of HIF-1α by YC-1 led to a significant decrease in DEC1 induced by hypoxia (P<0.05). We suggest that hypoxia induced the overexpression of DEC1, the mechanism of which may be related to the upregulation of HIF-1α in HCC. The efficacy of inhibiting HIF-1α and DEC1 expression as a possible treatment for HCC should be assessed in clinical trials.

The distinct expression patterns of claudin-2, -6, and -11 between human gastric neoplasms and adjacent non-neoplastic tissues

Background

Cancers have a multifactorial etiology a part of which is genetic. Recent data indicate that expression of the tight junction claudin proteins is involved in the etiology and progression of cancer.

Methods

To explore the correlations of the tight junction proteins claudin-2,-6, and −11 in the pathogenesis and clinical behavior of gastric cancer, 40 gastric cancer tissues and 28 samples of non-neoplastic tissues adjacent to the tumors were examined for expression of claudin-2,-6, and −11 by streptavidin-perosidase immunohistochemical staining method.

Results

The positive expression rates of claudin-2 in gastric cancer tissues and adjacent tissues were 25% and 68% respectively (P < 0.001). The positive expression rates of claudin-6 in gastric cancer tissues and adjacent tissues were 55% and 79% respectively (P = 0.045 < 0.05). In contrast, the positive expression rates of claudin-11 in gastric cancer tissues and gastric cancer adjacent tissues were 80% and 46% (P = 0.004 < 0.01). Thus in our study, the expression of claudin-2, and claudin-6 was down regulated in gastric cancer tissue while the expression of claudin-11 was up regulated. Correlations between claudin expression and clinical behavior were not observed.

Conclusion

Our study provides the first evidence that claudin-2,-6, and −11 protein expression varies between human gastric cancers and adjacent non-neoplastic tissues.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5470513569630744

Reduced expression of miR-22 in gastric cancer is related to clinicopathologic characteristics or patient prognosis

Objective

Involvements of microRNA-22 (miR-22) in cancer development have attracted much attention, but its role in tumorigenesis of gastric cancer is still largely unknown. Therefore, the aim of this study was to investigate the expression patterns and clinical implications of miR-22 in gastric cancer.

Methods

Quantitative RT-PCR was performed to evaluate the expression levels of miR-22 in 98 pairs of gastric cancer and normal adjacent mucosa.

Results

Compared with normal adjacent mucosa, miR-22 expression was significantly downregulated in gastric cancer tissues (P < 0.001). Of 98 patients with gastric cancer, 58 (59.2%) were placed in the low miR-22 expression group and 40 (40.8%) were placed in the high miR-22 expression group. In addition, tumors with low miR-22 expression had greater extent of lymph node metastasis (P = 0.02) and distant metastasis (P = 0.01), and were at a worse stage (P = 0.01) than the tumors with high miR-22 expression. Moreover, the gastric cancer patients with low miR-22 expression had shorter overall survival than those with high miR-22 expression (P = 0.03). MiR-22, determined by multivariate analysis, was an independent prognostic factor for patients with gastric cancer.

Conclusion

Our data offer the convincing evidence that the reduced expression of miR-22 was significantly associated with malignant development of gastric cancer and may be a novel prognostic marker of this disease. miR-22 might have potentials in the application of cancer therapy for patients with gastric cancer.