MCM8 promotes gastric cancer progression through RPS15A and predicts poor prognosis.

BACKGROUND: Gastric cancer (GC) is the fourth leading cause of cancer-related death worldwide. Minichromsome maintenance proteins family member 8 (MCM8) assists DNA repair and DNA replication. MCM8 exerts tumor promotor function in multiple digestive system tumors. MCM8 is also considered as a potential cancer therapeutic target. METHODS: Bioinformatics methods were used to analyze MCM8 expression and clinicopathological significance. MCM8 expression was detected by immunohistochemistry (IHC) staining and qRT-PCR. MCM8 functions in GC cell were explored by Celigo cell counting, colony formation, wound-healing, transwell, and annexin V-APC staining assays. The target of MCM8 was determined by human gene expression profile microarray. Human phospho-kinase array kit evaluated changes in key proteins after ribosomal protein S15A (RPS15A) knockdown. MCM8 functions were reassessed in xenograft mouse model. IHC detected related proteins expression in mouse tumor sections. RESULTS: MCM8 was significantly upregulated and predicted poor prognosis in GC. High expression of MCM8 was positively correlated with lymph node positive (p < 0.001), grade (p < 0.05), AJCC Stage (p < 0.001), pathologic T (p < 0.01), and pathologic N (p < 0.001). MCM8 knockdown inhibited proliferation, migration, and invasion while promoting apoptosis. RPS15A expression decreased significantly after MCM8 knockdown. It was also the only candidate target, which ranked among the top 10 downregulated differentially expressed genes (DEGs) in sh-MCM8 group. RPS15A was identified as the target of MCM8 in GC. MCM8/RPS15A promoted phosphorylation of P38α, LYN, and p70S6K. Moreover, MCM8 knockdown inhibited tumor growth, RPS15A expression, and phosphorylation of P38α, LYN, and p70S6K in vivo. CONCLUSIONS: MCM8 is an oncogene and predicts poor prognosis in GC. MCM8/RPS15A facilitates GC progression.

Quercetin induces ferroptosis in gastric cancer cells by targeting SLC1A5 and regulating the p-Camk2/p-DRP1 and NRF2/GPX4 Axes.

Quercetin (Quer) is a natural flavonoid known for its inhibitory effects against various cancers. However, the mechanism by which Quer inhibits gastric cancer (GC) has not yet been fully elucidated. Ferroptosis, a mode of programmed cell death resulting from lipid peroxidation, is regulated by abnormalities in the antioxidant system and iron metabolism. Through flow cytometry and other detection methods, we found that Quer elevated lipid peroxidation levels in GC cells. Transmission electron microscopy confirmed an increase in ferroptosis in Quer-induced GC. We demonstrated that Quer inhibits SLC1A5 expression. Molecular docking revealed Quer's binding to SLC1A5 at SER-343, SER-345, ILE-423, and THR-460 residues. Using immunofluorescence and other experiments, we found that Quer altered the intracellular ROS levels, antioxidant system protein expression levels, and iron content. Mechanistically, Quer binds to SLC1A5, inhibiting the nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2), resulting in decreased xCT/GPX4 expression. Quer/SLC1A5 signaling activated p-Camk2, leading to upregulated p-DRP1 and enhanced ROS release. Additionally, Quer increased the intracellular iron content by inhibiting SLC1A5. These three changes collectively led to ferroptosis in GC cells. In conclusion, Quer targets SLC1A5 in GC cells, inhibiting the NRF2/xCT pathway, activating the p-Camk2/p-DRP1 pathway, and accelerating iron deposition. Ultimately, Quer promotes ferroptosis in GC cells, inhibiting GC progression. Overall, our study reveals that Quer can potentially impede GC progression by targeting SLC1A5, offering novel therapeutic avenues through the modulation of ferroptosis and iron homeostasis.

Hydroxyphenyl Butanone Induces Cell Cycle Arrest through Inhibition of GSK3ß in Colorectal Cancer.

BACKGROUND: Colorectal cancer (CRC) is among the top three gastrointestinal malignancy in morbidity and mortality. The abnormal activation of Wnt/ß-catenin pathway is considered to be a key factor in the occurrence and development of CRC. Novel inhibitor discovery against key factor in WNT pathway is important for CRC treatment and prevention. METHODS: Cell proliferation was detected after hydroxyphenyl butanone treatment in human colorectal cancer HCT116, LOVO, and normal colonic epithelial NCM460 cells. Colony formation, cell invasion ability, and cell cycle were detected with and without GSK-3ß knockdown. RESULTS: Hydroxyphenyl butanone induces cycle arresting on G1-S phase of colorectal cancer cell line through GSK3ß in Wnt/ß-catenin pathway and inhibits malignant biological manifestations of cell proliferation, colony formation, and invasion. The inhibition in the high concentration group is stronger than that in the low concentration group, and the antitumor effect is different for different tumor cells. Under the same concentration of natural hydroxyphenyl butanone, the inhibition on normal colonic epithelial cells is significantly lower than that on tumor cells. The natural hydroxyphenyl butanone with medium and low concentration could promote the proliferation of normal colonic epithelial cells. CONCLUSION: This study illustrated natural hydroxyphenyl butanone as new inhibitor of GSK3ß and revealed the mechanisms underlying the inhibitory effects in colorectal cancer.

Ellagic acid induces cell cycle arrest and apoptosis via the TGF­ß1/Smad3 signaling pathway in human colon cancer HCT­116 cells.

Colorectal carcinoma (CRC) is a major type of malignancy worldwide. Ellagic acid (EA), a natural phenolic constituent, has been shown to exhibit anticancer effects. In our previous study, it was shown that EA inhibited proliferation of CRC cells. Additionally, microarray analysis revealed 4,738 differentially expressed genes (DEGs) which were associated with multiple cellular events, including cell growth, apoptosis and angiogenesis. However, the associated pathways had not been validated. In the present study, it was shown that EA induced G0/G1 cell cycle arrest in HCT­116 cells, and increased apoptosis. Furthermore, DEGs identified by cDNA microarray analysis were investigated, and showed changes in five genes which were associated with the TGF­ß1/Smad3 signaling pathway. TGF­ß1 small interfering RNA and SIS3, a Smad3 inhibitor, were used to assess the role of TGF­ß1 and Smad3, respectively, and it was shown that the they reduced the effects of EA on HCT­116 CRC cells. In addition, the expression patterns of downstream DEGs of the TGF­ß1/Smad3 pathway were altered. Thus, this pathway may underlie the molecular mechanism by which EA exhibits its effects in vitro in CRC cells. Accordingly, targeting the TGF­ß1/Smad3 pathway with anticancer agents such as EA may be potentially used to treat CRC.

KIF15 facilitates gastric cancer via enhancing proliferation, inhibiting apoptosis, and predict poor prognosis.

BACKGROUND: Kinesin superfamily proteins (KIFs) can transport membranous organelles and protein complexes in an ATP-dependent manner. Kinesin family member 15 (KIF15) is overexpressed in various cancers. However, the function of KIF15 in gastric cancer (GC) is still unclear. METHODS: GC patients' data from The Cancer Genome Atlas (TCGA) were analyzed by bioinformatics methods. The expression of KIF15 was examined in GC and paracarcinoma tissues from 41 patients to verify the analysis results. The relationship between KIF15 expression and clinical characteristics were also observed by bioinformatics methods. Kaplan-Meier survival analysis of 122 GC patients in our hospital was performed to explore the relationship between KIF15 expression levels and GC patients' prognosis. KIF15 was downregulated in GC cell lines AGS and SGC-7901 by transfecting a lentivirus-mediated shRNA plasmid targeting KIF15. In vitro, GC cell proliferation and apoptosis were detected by MTT assay, colony formation assay, and Annexin V-APC staining. In vivo, xenograft experiments were used to verify the in vitro results. Furthermore, Human Apoptosis Antibody Array kit was used to screen possible targets of KIF15 in GC cell lines. RESULTS: The bioinformatics results showed that KIF15 expression levels were higher in GC tissues than in normal tissues. IHC showed same results. High expression of KIF15 was statistical correlated with high age and early histologic stage. Kaplan-Meier curves indicated that high KIF15 expression predict poor prognosis in patients with GC. MTT assay and colony formation assay showed that KIF15 promote GC cell proliferation. Annexin V-APC staining found that KIF15 can inhibit GC cell apoptosis. Xenograft experiments reveal that downregulating KIF15 can inhibit GC tumor growth and promote GC apoptosis. Through detection of 43 anti-apoptotic proteins by the Human Apoptosis Antibody Array kit, it was confirmed that knocking down KIF15 can reduce seven anti-apoptotic proteins expression. CONCLUSIONS: Taken together, our study revealed a critical role for KIF15 to inhibit GC cell apoptosis and promote GC cell proliferation. KIF15 may decrease anti-apoptotic proteins expression by regulating apoptosis pathways. High expression of KIF15 predicts a poor prognosis in patients with GC. KIF15 might be a novel prognostic biomarker and a therapeutic target for GC.

Overexpression of microRNA-216a inhibits autophagy by targeting regulated MAP1S in colorectal cancer.

Background: Autophagy executes the rapid degradation of unneeded proteins and organelles through the lysosomal pathway, and is a crucial catabolic process widely conserved among eukaryotes. miRNAs can modulate autophagy by targeting genes encoding proteins involved in the process. A great deal of researchhas indicated that miR-216a was a functional miRNA related to tumorigenesis. However, the contribution of miR-216a to autophagy in colorectal cancer (CRC) remains unclear. The purpose of this study was to investigate the role of miR-216a in autophagy in CRC cells. Methods: The expression levels of miR-216a in 67 paired CRC patients were evaluated by qRT-PCR. Direct gene targeting predicted by TargetScan and miRanda was confirmed by luciferase activity. Western blot and flow cytometry were used to identify the regulatory mechanism of miR-216a on autophagy in CRC cells. Results: We determined that miR-216a is downregulated in CRC by screening its expression in 67 CRC tissue samples. Dual luciferase reporter assays showed that miR-216a binds the 3'-UTR of MAP1S, suggesting that MAP1S is a direct target of miR-216a. miR-216a could inhibit autophagy in HCT-116 and HT-29 CRC cells through downregulating MAP1S expression. Flow cytometry and Western blot analysis demonstrated that overexpression of miR-216a reduced MAP1S mRNA and protein levels. Moreover, we determined that miR-216a-regulated inhibition of autophagy via MAP1S regulation involves the TGF-ß pathway. Conclusion: Taken together, our findings indicate that miR-216a was a tumor-suppressor miRNA in human CRC, which can inhibit autophagy via the TGF-ß/MAP1S pathway.

Circular RNA circ-DONSON facilitates gastric cancer growth and invasion via NURF complex dependent activation of transcription factor SOX4.

BACKGROUND: Circular RNAs (circRNAs) are a novel type of noncoding RNAs and play important roles in tumorigenesis, including gastric cancer (GC). However, the functions of most circRNAs remain poorly understood. In our study, we aimed to investigate the functions of a new circRNA circ-DONSON in GC progression. METHODS: The expression of circ-DONSON in gastric cancer tissues and adjacent normal tissues was analyzed by bioinformatics method, qRT-PCR, Northern blotting and in situ hybridization (ISH). The effects of circ-DONSON on GC cell proliferation, apoptosis, migration and invasion were measured by using CCK8, colony formation, EdU, immunofluorescence (IF), FACS and Transwell assays. qRT-PCR and Western blotting were utilized to validate how circ-DONSON regulates SOX4 expression. ChIP, DNA fluorescence in situ hybridization (DNA-FISH) and DNA accessibility assays were used to investigate how circ-DONSON regulates SOX4 transcription. The interaction between circ-DONSON and NURF complex was evaluated by mass spectrum, RNA immunoprecipitation (RIP), pulldown and EMSA assays. Xenograft mouse model was used to analyze the effect of circ-DONSON on GC growth in vivo. RESULTS: Elevated expression of circ-DONSON was observed in GC tissues and positively associated with advanced TNM stage and unfavorable prognosis. Silencing of circ-DONSON significantly suppressed the proliferation, migration and invasion of GC cells while promoting apoptosis. circ-DONSON was localized in the nucleus, recruited the NURF complex to SOX4 promoter and initiated its transcription. Silencing of the NURF complex subunit SNF2L, BPTF or RBBP4 similarly attenuated GC cell growth and increased apoptosis. circ-DONSON knockdown inhibited GC growth in vivo. CONCLUSION: circ-DONSON promotes GC progression through recruiting the NURF complex to initiate SOX4 expression.

Fresh red raspberry phytochemicals suppress the growth of hepatocellular carcinoma cells by PTEN/AKT pathway.

The red raspberry (Rubus idaeus L.) is a common fruit worldwide and its extract has been found to inhibit the growth of many types of tumors, mainly because it is rich in bioactive phytochemicals. However, the mechanism underlying its anticancer activity in hepatocellular carcinoma (HCC) is not well understood. Herein, the aim of this study was to determine the effects of red raspberry phytochemicals on the proliferation of hepatocellular carcinoma cells and to elucidate its biochemical and molecular targets. CCK8 and colony formation, as well as flow cytometry assays, were employed to determine the effects of red raspberry extract (RRE) on cell proliferation and cell cycle distribution in HCC cells. Our results showed that RRE significantly inhibited cell proliferation and arrested cell cycle progression at the S phase in HCC cells. RRE increased the expression of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) by reducing the methylation status of the PTEN gene promoter and inhibiting DNMT1 expression and regulated AKT signaling pathway. These findings show that red raspberry phytochemicals inhibit the proliferation of HCC cells by regulating PTEN/AKT signaling pathway, providing evidence that RRE may be used as a potential auxiliary therapy for patients with HCC.

Multiple effects of ellagic acid on human colorectal carcinoma cells identified by gene expression profile analysis.

Colorectal carcinoma (CRC) is the third most commonly diagnosed cancer in the world. Phytochemicals have become a research hotspot in recent years as cancer prevention and treatment agents due to their low toxicity and limited side-effects. Ellagic acid (EA), a natural phenolic constituent, displays various biological activities, including anticancer effects. However, the detailed anticancer mechanisms of EA remain unclear. In the present study, we found that EA inhibited the growth of HCT-116 colon cancer cells. Moreover, we identified differentially expressed genes (DEGs) by microarray profiling of HCT-116 cells treated with EA. A total of 857 DEGs (363 upregulated and 494 downregulated) were identified with a >1.5-fold change in expression after treatment with EA for 72 h. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that a large number of cellular functions were modified by EA including proliferation, apoptosis, cell cycle and angiogenesis. Interaction network analysis using DEGs provided details of their interactions and predicted the key target pathways of EA. To verify the result of cDNA microarray, 10 selected DEGs related to proliferation, apoptosis or cell cycle were further confirmed by real-time RT-PCR. Based on microarray data, we identified several crucial functions of EA. These results provide important new data for EA in anti-CRC research.

Discovery and Validation of Hypermethylated Markers for Colorectal Cancer.

Colorectal carcinoma (CRC) is one of the most prevalent malignant tumors worldwide. Screening and early diagnosis are critical for the clinical management of this disease. DNA methylation changes have been regarded as promising biomarkers for CRC diagnosis. Here, we map DNA methylation profiling on CRC in six CRCs and paired normal samples using a 450 K bead array. Further analysis confirms the methylation status of candidates in two data sets from the Gene Expression Omnibus. Receiver operating characteristic (ROC) curves are calculated to determine the diagnostic performances. We identify 1549 differentially methylated regions (DMRs) showing differences in methylation between CRC and normal tissue. Two genes (ADD2 and AKR1B1), related to the DMRs, are selected for further validation. ROC curves show that the areas under the curves of ADD2 and AKR1B1 are higher than that of SEPT9, which has been clinically used as a screening biomarker of CRC. Our data suggests that aberrant DNA methylation of ADD2 and AKR1B1 could be potential screening markers of CRC.

Integrated analysis of genome-wide DNA methylation and gene expression profiles identifies potential novel biomarkers of rectal cancer.

DNA methylation was regarded as the promising biomarker for rectal cancer diagnosis. However, the optimal methylation biomarkers with ideal diagnostic performance for rectal cancer are still limited. To identify new molecular markers for rectal cancer, we mapped DNA methylation and transcriptomic profiles in the six rectal cancer and paired normal samples. Further analysis revealed the hypermethylated probes in cancer prone to be located in gene promoter. Meanwhile, transcriptome analysis presented 773 low-expressed and 1,161 over-expressed genes in rectal cancer. Correction analysis identified a panel of 36 genes with an inverse correlation between methylation and gene expression levels, including 10 known colorectal cancer related genes. From the other 26 novel marker genes, GFRA1 and GSTM2 were selected for further analysis on the basis of their biological functions. Further experiment analysis confirmed their methylation and expression status in a larger number (44) of rectal cancer samples, and ROC curves showed higher AUC than SEPT9, which has been used as a biomarker in rectal cancer. Our data suggests that aberrant DNA methylation of contiguous CpG sites in methylation array may be potential diagnostic markers of rectal cancer.

Tumor-suppressive microRNA-34a inhibits breast cancer cell migration and invasion via targeting oncogenic TPD52.

The tumor protein D52 (TPD52) is an oncogene overexpressed in breast cancer. Although the oncogenic effects of TPD52 are well recognized, how its expression and the role in migration/invasion is still not clear. This study tried to explore the regulative role of microRNA-34a (miR-34a), a tumor suppressive miRNA, on TPD52 expression in breast cancer. The expression of miR-34a was found significantly decreased in breast cancer specimens with lymph node metastases and breast cancer cell lines. The clinicopathological characteristics analyzed showed that lower expression levels of miR-34a were associated with advanced clinical stages. Moreover, TPD52 was demonstrated as one of miR-34a direct targets in human breast cancer cells. miR-34a was further found significantly repress epithelial-mesenchymal transition (EMT) and inhibit breast cancer cell migration and invasion via TPD52. These findings indicate that miR-34a inhibits breast cancer progression and metastasis through targeting TPD52. Consequently, our data strongly suggested that oncogenic TPD52 pathway regulated by miR-34a might be useful to reveal new therapeutic targets for breast cancer.