KHSRP has oncogenic functions and regulates the expression and alternative splicing of DNA repair genes in breast cancer MDA-MB-231 cells.

Breast cancer has become the most common type of cancers worldwide. Its high prevalence and malignant features are associated with various environmental factors and molecules. The KH-type splicing regulatory protein (KHSRP) participates in the development of breast cancer, while the underlying mechanisms are largely unknown. In this study, we silenced KHSRP expression in MDA-MB-231 cells by small interfering RNA (siKHSRP), and then assessed its effects on cellular features. Finally, we performed whole transcriptome sequencing (RNA-seq) experiments to explore the downstream targets of KHSRP, and validated their changed pattern using quantitative polymerase chain reaction. We found KHSRP showed higher expression level and was associated with worse prognosis in breast cancer patients. In siKHSRP samples, the proliferation, invasion, and migration abilities were significantly repressed compared with negative control (NC) samples, while the apoptosis level was increased. By investigating the RNA-seq data, we found KHSRP globally regulates the expression and alternative splicing profiles of MDA-MB-231 cells by identifying 1632 differentially expressed genes (DEGs) and 1630 HKSRP-regulated AS events (RASEs). Functional enriched analysis of DEGs demonstrated that cilium assembly and movement and extracellular matrix organization pathways were specifically enriched in up DEGs, consistent with the repressed migration and invasion abilities in siKHSRP cells. Interestingly, the cell cycle and DNA damage and repair associated pathways were enriched in both down DEGs and RASE genes, suggesting that KHSRP may modulate cell proliferation by regulating genes in these pathways. Finally, we validated the changed expression and AS patterns of genes in cell cycle and DNA damage/repair pathways. Expression levels of BIRC5, CCNA2, CDK1, FEN1, FOXM1, PTTG1, and UHRF1 were downregulated in siKHSRP samples. The AS patterns of PARK7, ERCC1, CENPX, and UBE2A were also dysregulated in siKHSRP samples and confirmed PCR experiments. In summary, our study comprehensively explored the downstream targets and their functions of KHSRP in breast cancer cells, highlighting the molecular mechanisms of KHSRP on the oncogenic features of breast cancer. The identified molecular targets could be served as potential therapeutic targets for breast cancer in future.

Distribution of CYP2D6 and CYP2C19 gene polymorphisms in Han and Uygur populations with breast cancer in Xinjiang, China.

The aim of this study was to investigate the frequency distribution of the cytochrome P450 (CYP450) enzymes, CYP2D6 and CYP2C19, and the form of tamoxifen metabolisation in premenopausal patients with breast cancer in the Han and Uygur ethnic groups of Xinjiang to guide rational clinical drug use. A total of 125 Han patients and 121 Uygur patients with premenopausal hormone-receptor-positive breast cancer treated at the Xinjiang Uygur Autonomous Region Cancer Hospital between 1 June 2011 and 1 December 2013 were selected. The common mutation sites in CYP450 were analysed using TaqMan® minor groove binder technology. Genetic testing was performed to determine other metabolic types of tamoxifen, and the genotypes and metabolic types were compared using a Chi-squared test. Between the Han and Uygur groups, there were significant differences in the frequencies of the CYP2D6 (*10/*10) and CYP2C19 (*1/*1) genotypes, with P-values of 0.002 and 0.015, respectively. Genotypes of CYP2D6 (*1/*1), CYP2D6 (*1/*5), CYP2D6 (*5/*5), CYP2D6 (*5/*10) and CYP2C19 (*3/*3) were expressed in the two patient groups, and the difference was not statistically significant (P > 0.05). In the Han patients, the proportions of extensive, intermediate and poor metabolisers of tamoxifen were 72, 24 and 4%, respectively, whereas those in the Uygur patients were 76.9, 17.4 and 5.7%, respectively, with no significant difference (P > 0.05). In conclusion, There were partial differences in the CYP2D6 and CYP2C19 gene polymorphisms of CYP450 between the Han and Uygur patients with premenopausal breast cancer, but there was no significant difference between the CYP2D6 and CYP2C19 phenotypes. Further research is needed to determine the relationship between the enzyme genetic differences of CYP450 and the pharmacokinetics and efficacy of tamoxifen. Although there were some differences in genotypes, these did not result in differences in the predicted tamoxifen metabolisation phenotype between the Han and Uygur patients with breast cancer. Therefore, the doses should be adjusted according to the individual genotype data.

Identification of biomarkers related to tumorigenesis and prognosis in breast cancer.

Background: The aim of the present study was to identify the central genes and prognostic index of breast cancer, and to determine the relationship between prognostic index and immune infiltration levels to provide useful information for the diagnosis and treatment of breast cancer. Methods: The Cancer Genome Atlas breast cancer dataset and 2 microarray datasets were applied to screen overlapping differentially expressed genes (DEGs) between breast cancer tissue and normal breast tissue samples. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were conducted through the Database for Annotation, Visualization, and Integrated Discovery. Protein-protein interaction (PPI) networks were used to screen hub genes of the overlapping DEGs. Gene Expression Profiling Interactive Analysis (GEPIA), The University of ALabama at Birmingham CANcer data analysis Portal (UALCAN), and The Human Protein Atlas (HPA) databases were used to validate their expression. The correlation of hub genes with immune infiltration was analyzed using TISIDB software. Kaplan-Meier Plotter was used to analyze the prognosis of hub genes. Results: Ten hub genes [cyclin A2 (CCNA2), cyclin dependent kinase 1 (CDK1), centromere protein F (CENPF), kinesin family member 2C (KIF2C), kinesin family member 4A (KIF4A), maternal embryonic leucine zipper kinase (MELK), PDZ binding kinase (PBK), protein regulator of cytokinesis 1 (PRC1), DNA topoisomerase II alpha (TOP2A), and TPX2 microtubule nucleation factor (TPX2)] were selected and their overexpression in breast cancer tissue was verified. All were associated with a poor prognosis for breast cancer. CDK1, CENPF, KIF2C, KIF4A, MELK, PBK, PRC1, and TPX2 were correlated with CD4 T cells in breast cancer, while TOP2A was correlated with CD8 T cells. Conclusions: The findings indicated that the 10 hub genes could be potential biomarkers for progression in breast cancer.

HOXD Antisense Growth-Associated Long Noncoding RNA Promotes Triple-Negative Breast Cancer Progression by Activating Wnt Signaling Pathway.

PURPOSE: Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer owing to high heterogeneity, aggressive nature, and lack of treatment options, which has a substantial deleterious effect on patients' lives. HOXD antisense growth-associated long noncoding RNA (lncRNA) (HAGLR) plays tumor-promoting roles in many cancers. In this study, we aimed to explore the role of HAGLR in TNBC. METHODS: Quantitative real-time polymerase chain reaction assays were used to examine the expression of RNAs. Functional experiments were conducted to test the biological behavior of TNBC cells. Moreover, MS2-RNA immunoprecipitation, luciferase reporter, and RNA pull-down assays were conducted to verify the binding relationship between HAGLR, microRNA-143-5p (miR-143-5p), and serine- and arginine-rich splicing factor 1 (SRSF1). RESULTS: HAGLR was found to be highly expressed in TNBC tissues and cells, and inhibiting HAGLR suppressed cell proliferation, migration, and invasion and promoted cell apoptosis in TNBC. Meanwhile, miR-93-5p was shown to bind to HAGLR and SRSF1. In addition, SRSF1 plays an oncogenic role in TNBC. Importantly, HAGLR could activate the Wnt signaling pathway by sponging miR-93-5p to upregulate SRSF1; thus, accelerating TNBC progression. CONCLUSION: HAGLR could promote the progression of TNBC through the miR-93-5p/SRSF1 axis to activate the Wnt signaling pathway.

miR­455­5p promotes cell invasion and migration in breast cancer.

MicroRNA (miR)­455­5p has been identified as a biomarker for various types of cancer and may therefore be involved in the regulation of cancer development and progression. However, the specific role and function of miR­455­5p in breast cancer remains unclear. The present study explored the expression levels and function of miR­455­5p in breast cancer. The results from reverse transcription­quantitative polymerase chain reaction analysis revealed that miR­455­5p was significantly upregulated in breast cancer. Clinically, increased expression of miR­455­5p predicted a poor survival rate and miR­455­5p was identified as one of the independent prognostic factors for breast cancer patients. Furthermore, results from wound healing and Transwell assays revealed that miR­455­5p accelerated invasiveness and migration capabilities of breast cancer cells. In addition, programmed cell death 4 was identified as a downstream target of miR­455­5p and its expression was observed to be negatively regulated by miR­455­5p. Overall, miR­455­5p may function as an oncogene in breast cancer, and may therefore be used as a prognostic marker for breast cancer patients.