A Comprehensive Study to Investigate the Tumor-Suppressive Role of Radix Bupleuri on Gastric Cancer with Network Pharmacology and Molecular Docking.

Background: Gastric cancer (GC) is a common fatal malignancy. The aim of this study was to explore and validate the tumor-suppressive role and mechanism of Radix Bupleuri in GC. Methods: The active constituents of Radix Bupleuri were screened using TCMSP database. SwissTargetPrediction database was used to predict potential target genes of the compounds. GeneCards, TTD, DisGeNET, OMIM, and PharmGKB databases were used to search for GC-related targets. STRING database and Cytoscape 3.10 software were used for protein-protein interaction network construction and screening of core targets. DAVID database was used for GO and KEGG analyses. Core targets were validated using molecular docking. Cell proliferation and apoptosis were detected using CCK-8 and flow cytometry after GC cells were treated with isorhamnetin. The mRNA and protein expression levels of genes were detected using qRT PCR and Western blot. The metastasis potential of GC cells was evaluated in a nude mouse model. Results: A total of 371 potential targets were retrieved by searching the intersection of Radix Bupleuri and GC targets. Petunidin, 3',4',5',3,5,6,7-Heptamethoxyflavone, quercetin, kaempferol, and isorhamnetin were identified as the main bioactive compounds in Radix Bupleuri. SRC, HSP90AA1, AKT1, and EGFR, were core targets through which Radix Bupleuri suppressed GC. The tumor-suppressive effect of Radix Bupleuri on GC was mediated by multiple pathways, including PI3K-AKT, cAMP, and TNF signaling. The key compounds of Radix Bupleuri had good binding affinity with the core target. Isorhamnetin, a key component of Radix Bupleuri, could inhibit proliferation and metastasis, and induces apoptosis of GC cells. In addition, isorhamnetin could also reduce the mRNA expression of core targets, and the activation of PI3K/AKT pathway. Conclusion: This study identified potential targets and pathways of Radix Bupleuri against GC through network pharmacology and molecular docking, providing new insights into the pharmacological mechanisms of Radix Bupleuri in GC treatment.

KCNE4 expression is correlated with the pathological characteristics of colorectal cancer patients and associated with the radioresistance of cancer cells.

BACKGROUND: Colorectal cancer (CRC) is a common malignancy, and radioresistance limits the effectiveness of radiotherapy for rectal cancer. This study is performed to investigate the role and regulatory mechanism of Potassium Voltage-Gated Channel Subfamily E Regulatory Subunit 4 (KCNE4) in the radioresistance of CRC cells. METHODS: Immunohistochemical staining results of KCNE4 in normal tissues and CRC tissues were obtained from the Human Protein Atlas (HPA) database. The UALCAN database was used for analyzing KCNE4 mRNA expression in normal tissue samples and CRC tissue samples and its relationship with tumor stage. The relationship of KCNE4 expression with prognosis was analyzed utilizing the data of GEPIA database. LinkedOmics database was searched to analyze the co-expressed gene sets of KCNE4 in CRC, and to analyze the signaling pathways related with KCNE4 in CRC. GO and KEGG enrichment analyses were carried out on the co-expressed genes of KCNE4 with DAVID database. Ionizing radiation (IR)-resistant cell lines (HCT116/IR and HT29/IR) were established; cell viability was assessed via cell counting kit-8 (CCK-8) and EdU assays, and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay was performed for detecting cell apoptosis. Western blotting was carried out to detect the expressions of p-p85 and p-AKT. RESULTS: KCNE4 was highly expressed in CRC tissues and linked to advanced tumor stage, lymph node metastasis and poor prognosis of CRC patients. KCNE4 overexpression promoted HCT116/IR cell proliferation and inhibited the apoptosis, while KCNE4 knockdown suppressed HT29/IR cell proliferation and facilitated the apoptosis. Furthermore, high KCNE4 expression was associated with the activation of the PI3K/AKT signal pathway. CONCLUSION: KCNE4 is associated with the clinicopathological characteristics of CRC patients, and its high expression level contributes to the radioresistance of cancer cells via activating the PI3K/AKT signal pathway.

Circular RNA hsa_circ_0026344 suppresses gastric cancer cell proliferation, migration and invasion via the miR-590-5p/PDCD4 axis.

OBJECTIVES: Circular RNA (CircRNA) is a class of non-coding RNA transcripts, with multiple pathophysiological functions. Instead, the mechanism and function of circRNA in gastric cancer (GC) are not fully deciphered. METHODS: CircRNA_0026344 (circ_0026344), microRNA (miR)-590-5p and programmed cell death 4 (PDCD4) mRNA expression levels in GC tissues and cells were probed by quantitative real-time PCR. Cell viability, migration and aggressiveness were examined by cell counting kit-8 and transwell assays. Additionally, the interplay among circ_0026344, miR-590-5p and PDCD4 was verified with bioinformatics and dual-luciferase reporter gene assay. Western blot was conducted to probe PDCD4 protein expression. KEY FINDINGS: Circ_0026344 expression was underexpressed in GC tissues and cells, which was associated with clinicopathological characteristics such as tumour size, tumor-node-metastasis stage and lymph node metastasis. Circ_0026344 overexpression restrained the malignant biological behaviours of GC cells, while circ_0026344 knockdown functioned oppositely. Circ_0026344 could act as a competing endogenous RNA of miR-590-5p to negatively modulate its expression, and this miRNA could mitigate the impact of circ_0026344 on GC cells. In addition, PDCD4 was identified as the downstream target of miR-590-5p, and PDCD4 expression was positively modulated by circ_0026344. CONCLUSIONS: Circ_0026344 up-regulates PDCD4 expression via sponging miR-590-5p, thus inhibiting the progression of GC. This study further expounds the underlying molecular mechanism in the GC progression.

TNNT1, negatively regulated by miR-873, promotes the progression of colorectal cancer.

BACKGROUND: Troponin T1 (TNNT1) is a subunit of troponin that has been linked to neuromuscular disorder. Recently, it was reported that TNNT1 facilitates the proliferation of breast cancer cells. Interestingly, Cancer Genome Atlas data indicate that its overexpression is associated with an unfavorable prognosis of colorectal cancer (CRC) patients. The present study aimed to explore the expression, function and mechanism of dysregulation of TNNT1 in CRC. METHODS: Immunohistochemical staining and a real-time polymerase chain reaction were used to compare the expression level of TNNT1 in CRC tissues and adjacent tissues. Western blotting was used to detect the expression of TNNT1 in cell lines. Kaplan-Meier analysis and a chi-squared test were applied to evaluate the potential of TNNT1 to function as a cancer biomarker. RNA interference was used to inhibit TNNT1 expression in CRC cells, followed by detection of cell proliferation, apoptosis, migration and invasion. A luciferase reporter gene assay was used to determine the regulatory relationship between miR-873 and TNNT1. RESULTS: In the present study, we found that TNNT1 was significantly up-regulated in CRC samples and cell lines. The up-regulation of TNNT1 was also associated with several clinicopathologic features, and its high expression was correlated with an unfavorable prognosis of the patients. Knockdown of TNNT1 markedly arrested proliferation, migration and invasion, whereas it also promoted apoptosis. TNNT1 was identified as a target gene of miR-873, and there was a negative correlation among CRC samples. CONCLUSIONS: In conclusion, we have demonstrated that TNNT1, regulated by miR-873, is an oncogene of CRC associated with patient prognosis.