Syndecan-2, negatively regulated by miR-20b-5p, contributes to 5-fluorouracil resistance of colorectal cancer cells via the JNK/ERK signaling pathway.

5-Fluorouracil (5-FU) resistance has been long considered as an obstacle to the efficacy of chemotherapy in colorectal cancer (CRC). In this study, we demonstrated the role of miR-20b-5p-regulated syndecan-2 (SDC2) in 5-FU resistance of CRC cells. 5-FU-resistant SW480 CRC cells were established by treatment of SW480 cells with stepwise increase of 5-FU concentration. The results showed that SDC2 was expressed significantly higher in SW480/5-FU cells than in SW480/WT cells as revealed by quantitative real-time polymerase chain reaction and western blot analysis. MTT assay and BrdU assay showed that SDC2 overexpression led to increased cell survival rate, while SDC2 knockdown reversed the drug resistance of SW480/5-FU cells. Wound healing and transwell invasion assays revealed that knockdown of SDC2 inhibited the migratory and invasive ability of SW480/5-FU cells. Moreover, animal experiments indicated that si-SDC2 plays a suppressive role in tumor growth in vivo. We also confirmed that miR-20b-5p interacted with SDC2, which reversed the effect of SDC2 in SW480/5-FU cells via the c-Jun N-terminal kinase (JNK)/extracellular regulated protein kinases (ERK) signaling pathway. These findings showed that JNK/ERK signaling pathway is involved in miR-20b-5p/SDC2 axis-mediated 5-FU resistance in SW480/5-FU cells, indicating that the miR-20b-5p/SDC2 axis is a potential target for reversing 5-FU resistance in CRC.

DNA hypomethylation promotes invasion and metastasis of gastric cancer cells by regulating the binding of SP1 to the CDCA3 promoter.

BACKGROUND: Cell division cycle associated protein-3 (CDCA3) has been reported frequently upregulated in various cancers. It has been progressively realized that changed DNA methylations occur in diverse carcinomas. However, the concrete involvement of CDCA3 and DNA methylation in gastric cancer (GC) still needs to be further elucidated. METHODS: In this study, quantitative reverse-transcription polymerase chain reaction (PCR) was utilized to determine the relative expressions of CDCA3 in GC and normal tissue samples. The methylation condition of CDCA3 was determined by bisulfite-sequencing PCR (BSP) and methylation-specific PCR (MSP). A chromatin immunoprecipitation (ChIP) assay and luciferase activity assay was used for the interaction between transcription factors and promoters and binding site determination, respectively. The effects of knockdown or overexpression of specificity protein 1 (SP1) or CDCA3 on GC cells in vitro were further assessed via wound healing assay, colony formation assay, and matrigel invasion assay. RESULTS: In comparison to paired normal tissues, CDCA3 expressions were significantly increased in the GC tissues. The CDCA3 expression was regulated by DNA methylation, with the CpG island hypomethylation responsible for CDCA3 upregulation of GC. ChIP assays verified that the activity of SP1 binding to the CDCA3 promoter was dramatically increased. When the CDCA3 expression was downregulated in MKN45 cells by knockdown SP1, the proliferation ability, healing ability, and invasive ability were significantly suppressed. CONCLUSION: The process by which SP1 bound to the nearest promoter region was expedited in GC cells, by which DNA was hypomethylated and CDCA3 expression was promoted. The effect on cell proliferation and invasion by CDCA3 was under the regulation of SP1 and also affected by hypomethylation of DNA.

MicroRNA-92a promotes proliferation and invasiveness of gastric cancer cell by targeting FOXO1 gene.

The aim of this study is to   investigate the effect of miRNA-92a on GC cell proliferation, migration and invasiveness, and the mechanism(s) involved.  Four GC cell lines (SGC-7901, BGC-823, MKN45 and HGC-27) and normal human gastric epithelial cells (GES1) were used in this study. MicroRNA-92a mimics or inhibitor were transfected into the cells. The results of transfection were assessed using real-time quantitative polymerase chain reaction (qRT-PCR). Cell proliferation, migration, invasiveness and apoptosis were determined using cell counting kit 8 (CCK-8), scratch test, Transwell invasion assay, and flow cytometric analysis, respectively. The protein target of miRNA-92a was predicted using Bioinformatics. The expression of FOXO1 protein was measured using Western blotting. The expression of miRNA-92a was significantly upregulated in GC cells, relative to normal gastric epithelial cells (p < 0.05). Overexpression of miRNA-92a significantly promoted the proliferation, migration and invasiveness of GC cells, but significantly inhibited their apoptosis (p < 0.05). MicroRNA-92a directly targeted FOXO1 gene, and significantly reduced its protein expression. Overexpression of miRNA-92a promotes the proliferation, migration and invasiveness of GC cells, and plays a role similar to that of oncogene. It directly targets FOXO1 gene by inhibiting its protein expression.

DDX21 functions as a potential novel oncopromoter in pancreatic ductal adenocarcinoma: a comprehensive analysis of the DExD box family.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal tumor with an ill-defined pathogenesis. DExD box (DDX) family genes are widely distributed and involved in various RNA metabolism and cellular biogenesis; their dysregulation is associated with aberrant cellular processes and malignancies. However, the prognostic significance and expression patterns of the DDX family in PDAC are not fully understood. The present study aimed to explore the clinical value of DDX genes in PDAC. METHODS: Differentially expressed DDX genes were identified. DDX genes related to prognostic signatures were further investigated using LASSO Cox regression analysis. DDX21 protein expression was analyzed using the UALCAN and human protein atlas (HPA) online tools and confirmed in 40 paired PDAC and normal tissues through Tissue Microarrays (TMA). The independent prognostic significance of DDX21 in PDAC was determined through the construction of nomogram models and calibration curves. The functional roles of DDX21 were investigated using gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA). Cell proliferation, invasion, and migration were assessed using Cell Counting Kit-8, colony formation, Transwell, and wound healing assays. RESULTS: Upregulation of genes related to prognostic signatures (DDX10, DDX21, DDX60, and DDX60L) was significantly associated with poor prognosis of patients with PDAC based on survival and recurrence time. Considering the expression profile and prognostic values of the signature-related genes, DDX21 was finally selected for further exploration. DDX21 was overexpressed significantly at both the mRNA and protein levels in PDAC compared to normal pancreatic tissues. DDX21 expression, pathological stage, and residual tumor were significant independent prognostic indicators in PDAC. Moreover, functional enrichment analysis revealed that Genes co-expressed with DDX21 are predominantly involved in RNA metabolism, helicase activity, ribosome biogenesis, cell cycle, and various cancer-related pathways, such as PI3K/Akt signaling pathway and TGF-ß signaling pathway. Furthermore, in vitro experiments confirmed that the knockdown of DDX21 significantly reduced MIA PaCa-2 cell viability, proliferation, migration, and invasion. CONCLUSIONS: Four signature-related genes could relatively precisely predict the prognosis of patients with PDAC. Specifically, DDX21 upregulation may signal an unfavorable prognosis by negatively affecting the biological properties of PDAC cells. DDX21 may be considered as a candidate therapeutic target in PDAC.

Systematic analysis of TREM2 and its carcinogenesis in pancreatic cancer.

Background: Triggering receptor expressed on myeloid cells 2 (TREM2), a transmembrane immunoglobulin-superfamily receptor, is expressed primarily on cells such as macrophages and dendritic cells. TREM2 has been shown to be associated with diseases such as neurodegeneration, fatty liver, obesity, and atherosclerosis. Currently, it has become one of the hotspots in oncology research. However, the role of TREM2 in pan-cancer, especially pancreatic cancer, remains unclear. Methods: We used the Tumor-immune System Interactions Database (TISIDB) to explore TREM2 expression differences, Tumor Immune Single-cell Hub 2 (TISCH2) to explore TREM2 expression distribution, Tumor IMmune Estimation Resource 2.0 (TIMER 2.0) to explore immune infiltration, cBio Cancer Genomics Portal (cBioPortal) to explore genetic variation, Genomics of Drug Sensitivity in Cancer (GDSC) to explore drug resistance, and Kaplan-Meier plotter database to explore the relationship between TREM2 and prognosis in pancreatic cancer. In addition, we used The Cancer Genome Atlas-pancreatic adenocarcinoma (TCGA-PAAD) and normal pancreas samples from the Genotype-Tissue Expression (GTEx) databases to explore the relationship between TREM2 and lymph node metastasis. We verified the protein level of TREM2 in pancreatic cancer by Human Protein Atlas (HPA) and western blotting and detected the colocalization of TREM2 with malignant cell markers by multiplex immunohistochemistry (mIHC). Finally, we identified the tumor-promoting role of TREM2 in pancreatic cancer via in vitro experiments, such as cell cycle assays, colony formation assays, and transwell migration and invasion assays. Results: Our results showed that TREM2 was differentially expressed in various tumors according to different molecular and immune subtypes of pan-cancer. It was found that TREM2 was mainly expressed in monocytes/macrophages. In addition, our study showed that TREM2 expression was closely associated with macrophages in the tumor microenvironment (TME) of pan-cancer. TREM2 was shown to be related to anti-inflammatory and immunosuppressive effects in most cancers. Furthermore, we found that amplification was the main somatic mutation of TREM2 in pan-cancer. Further correlational analysis revealed a significant negative association of TREM2 expression with sensitivity to AZD8186, which is a selective inhibitor of PI3K, but not gemcitabine and paclitaxel. Finally, through the knockdown and overexpression of TREM2, our findings verified that TREM2 on cancer cells promoted the progression of PAAD. Conclusions: In conclusion, our comprehensive analysis identified that TREM2 expression level was correlated with the TME and the immunosuppressive effects. In particular, our study indicated that TREM2 was involved in the progression of pancreatic cancer.

miR-92b promotes gastric cancer growth by activating the DAB2IP-mediated PI3K/AKT signalling pathway.

OBJECTIVES: miR-92b has been reported to play critical roles in several carcinomas; however, our understanding of the mechanisms by which miR-92b stimulates gastric cancer (GC) is incomplete. The aim of this study was to investigate the clinical significance and functional relevance of miR-92b in GC. MATERIALS AND METHODS: Expression of miR-92b in GC and peritumoural tissues was determined using qRT-PCR, in situ hybridization and bioinformatics. CCK-8, colony formation and fluorescence-activated cell sorting assays were utilized to explore the effect of miR-92b on GC cells. A luciferase reporter assay and Western blotting were employed to verify miR-92b targeting of DAB2IP. Furthermore, Western blotting was used to evaluate the levels of DAB2IP and PI3K/Akt signalling pathway-related proteins. RESULTS: In this study, we found that miR-92b was upregulated in GC tissues compared with peritumoural tissues. Overexpression of miR-92b promoted cell proliferation, colony formation, and G0 /G1 transition and decreased apoptosis. Our results indicated that miR-92b repressed the expression of DAB2IP and that loss of DAB2IP activated the PI3K/AKT signalling pathway. Overexpression of DAB2IP rescued the effects of miR-92b in GC cells. Finally, our results demonstrated a significant correlation between miR-92b expression and DAB2IP expression in GC tissues. CONCLUSIONS: Our results suggest that miR-92b promotes GC cell proliferation by activating the DAB2IP-mediated PI3K/AKT signalling pathway. The miR-92b/DAB2IP/PI3K/AKT signalling axis may be a potential therapeutic target to prevent GC progression.

Syndecan-2 in colorectal cancer plays oncogenic role via epithelial-mesenchymal transition and MAPK pathway.

PURPOSE: In this study, we aimed to elucidate the biological roles of Syndecan-2 (SDC2) in colorectal cancer (CRC), thereby further understanding its clinical role. METHODS: The expression of SDC2 was assessed by qRT-PCR and Western blot analysis. To understand the potential biological role of SDC2, we also explored the correlation between its expression level and clinicopathologic parameters. By using MTT, plate colony formation assay, Transwell invasion assays, and flow cytometry in vitro, the biological impact of SDC2 on CRC cell proliferation, migration, invasion, and apoptosis. In addition, the related signaling pathways were investigated. RESULTS: SDC2 expression was significantly upregulated in CRC tissues. The expression of SDC2 was highly associated with four parameters, i.e., stage (P < 0.01), vascular invasion (P = 0.0045), lymph node metastasis (P=0.0018), and distant metastasis (P = 0.0019). Knockdown of SDC2 significantly reduced proliferation, migration, and invasion of HCT116 and SW480 cells, and induced cell apoptosis. Moreover, SDC2 promoted epithelial-mesenchymal transition (EMT) in CRC cells, whereas the ratio of p-MEK/MEK and p-ERK/ERK markedly reduced after depleting SDC2. CONCLUSION: During CRC development, overexpression of SDC2 plays a carcinogenic role in CRC. Therapeutic solutions targeting SDC2 may provide potential insights into CRC prevention and treatment.

RGD-peptide conjugated inulin-ibuprofen nanoparticles for targeted delivery of Epirubicin.

Recently, chemotherapy-based polymeric nanoparticles have been extensively investigated for solid tumor treatment. Tumor targeted nanoparticles demonstrated great potential for improved accumulation in the tumor tissue, superior anticancer activity and reduced side effects. Thus, inulin-ibuprofen polymer was synthesized by esterification between inulin and ibuprofen, and RGD targeted epirubicin (EPB) loaded nanoparticles were prepared by the self-assembly of inulin-ibuprofen polymer and in situ encapsulation of EPB. RGD conjugated EPB loaded nanoparticles were characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). The EPB release from the nanoparticles showed pH-dependent profile and accelerated by the decreased pH value, which would favor the effective drug delivery in vivo. Intracellular uptake analysis suggested that RGD conjugated nanoparticles could be easily internalized by the cancer cells. In vitro cytotoxicity revealed that RGD conjugated EPB loaded nanoparticles exhibited the better antitumor efficacy compared with non-conjugated nanoparticles. More importantly, RGD conjugated EPB loaded nanoparticles showed superior anticancer effects and reduced toxicity than free EPB and non-conjugated nanoparticles by in vivo antitumor activity, EPB biodistribution and histology analysis.