Prostate apoptosis response 4 (PAR4) expression modulates WNT signaling pathways in MCF7 breast cancer cells: A possible mechanism underlying PAR4-mediated docetaxel chemosensitivity

Abnormal Long Non-Coding RNAs Expression Patterns Have the Potential Ability for Predicting Survival and Treatment Response in Breast Cancer

Abnormal long non-coding RNAs (lncRNAs) expression has been documented to have oncogene or tumor suppressor functions in the development and progression of cancer, emerging as promising independent biomarkers for molecular cancer stratification and patients’ prognosis. Examining the relationship between lncRNAs and the survival rates in malignancies creates new scenarios for precision medicine and targeted therapy. Breast cancer (BRCA) is a heterogeneous malignancy. Despite advances in its molecular classification, there are still gaps to explain in its multifaceted presentations and a substantial lack of biomarkers that can better predict patients’ prognosis in response to different therapeutic strategies. Here, we performed a re-analysis of gene expression data generated using cDNA microarrays in a previous study of our group, aiming to identify differentially expressed lncRNAs (DELncRNAs) with a potential predictive value for response to treatment with taxanes in breast cancer patients. Results revealed 157 DELncRNAs (90 up- and 67 down-regulated). We validated these new biomarkers as having prognostic and predictive value for breast cancer using in silico analysis in public databases. Data from TCGA showed that compared to normal tissue, MIAT was up-regulated, while KCNQ1OT1, LOC100270804, and FLJ10038 were down-regulated in breast tumor tissues. KCNQ1OT1, LOC100270804, and FLJ10038 median levels were found to be significantly higher in the luminal subtype. The ROC plotter platform results showed that reduced expression of these three DElncRNAs was associated with breast cancer patients who did not respond to taxane treatment. Kaplan–Meier survival analysis revealed that a lower expression of the selected lncRNAs was significantly associated with worse relapse-free survival (RFS) in breast cancer patients. Further validation of the expression of these DELncRNAs might be helpful to better tailor breast cancer prognosis and treatment.

Targeting the Wnt/β-catenin signaling pathway in cancer

The aberrant Wnt/β-catenin signaling pathway facilitates cancer stem cell renewal, cell proliferation and differentiation, thus exerting crucial roles in tumorigenesis and therapy response. Accumulated investigations highlight the therapeutic potential of agents targeting Wnt/β-catenin signaling in cancer. Wnt ligand/ receptor interface, β-catenin destruction complex and TCF/β-catenin transcription complex are key components of the cascade and have been targeted with interventions in preclinical and clinical evaluations. This scoping review aims at outlining the latest progress on the current approaches and perspectives of Wnt/β-catenin signaling pathway targeted therapy in various cancer types. Better understanding of the updates on the inhibitors, antagonists and activators of Wnt/β-catenin pathway rationalizes innovative strategies for personalized cancer treatment. Further investigations are warranted to confirm precise and secure targeted agents and achieve optimal use with clinical benefits in malignant diseases.

miR-601 inhibits proliferation, migration and invasion of prostate cancer stem cells by targeting KRT5 to inactivate the Wnt signaling pathway

OBJECTIVE

This study aimed to verify the hypothesis that downregulation of miR-601 inhibits the proliferation, migration, and invasion of prostate cancer stem cells (PCSCs) by the Wnt signaling pathway through targeting keratin 5 (KRT5).

METHODS

Bioinformatic tools were applied to predict miRNAs and genes potentially associated with prostate cancer, then miR-601 and KRT5 were selected. Subsequently, PCSCs were investigated with respect to miR-601 overexpression or inhibition, KRT5 overexpression, or treatment with a Wnt pathway inhibitor. A series of experiments including western blotting, RT-qPCR, wound healing experiment, transwell assay, MTT assay, annexin V-FITC/PI flow cytometric analysis, nude mice assay and immunohistochemistry were then carried out.

RESULTS

Compared with negative control group, migration, invasion, and proliferation of PCSCs and Wnt-1 expression were all enhanced, but apoptosis was attenuated in the miR-601 mimic group. Furthermore, results identified in the other groups (KRT5, miR-601 inhibitor, miR-601 inhibitor + KRT5, Wnt signaling pathway inhibitor, PRI-724/PRI-724 + KRT5) were opposite to those identified with the miR-601 mimic group (all P<0.05). Compared with the miR-601 inhibitor + KRT5 group, migration, invasion, and proliferation of PCSCs and Wnt-1 expression were all increased, whereas apoptosis was suppressed in KRT5 or miR-601 inhibitor groups (all P<0.05). Compared with the PRI-724 + KRT5 group, migration, invasion, and proliferation of PCSCs and Wnt-1 expression were also enhanced, whereas apoptosis was inhibited in PRI-724 or KRT5 groups (all P<0.05).

CONCLUSION

Results obtained from the present study have demonstrated that downregulation of miR-601 is able to inhibit the proliferation, migration, and invasion of PCSCs by activating KRT5, and subsequently inhibiting the Wnt pathway.

Identification and characterization of biomarkers and their functions for docetaxel-resistant prostate cancer cells

Docetaxel treatment is a standard chemotherapy strategy for castration-resistant prostate cancer (CRPC), and patients with CRPC eventually develop resistance to treatment. However, little is understood regarding the underlying mechanism of resistance. The present study aimed to identify the underlying crucial genes and regulatory networks associated with docetaxel resistance in prostate cancer using bioinformatics analyses. For this purpose, one expression profile dataset (GSE33455), which included two docetaxel-sensitive and two docetaxel-resistant cell lines, was downloaded from the Gene Expression Omnibus database, and analyses of differential gene expression and function enrichment were performed. A protein-protein interaction (PPI) network was constructed, and the associated hub genes were investigated using the Search Tool for the Retrieval of Interacting Genes/Proteins and Cytoscape software. A total of 756 differentially expression genes (DEGs) were identified, including 509 downregulated and 247 upregulated genes. Enrichment analysis revealed that the DEGs were associated with the interferon-γ-mediated signaling pathway, protein binding, bicellular tight junctions and cancer pathways. Two modules were screened from the PPI network, and the corresponding genes were identified to be largely enriched in the interferon-γ-mediated signaling pathway and the negative regulators of the DExD/H-Box helicase 58/interferon induced with helicase C domain 1 signaling pathway, and enriched in cell-cell adhesion and the Rap1 signaling pathway. Among the ten hub genes, epidermal growth factor receptor, spleen tyrosine kinase (SYK), intracellular adhesion molecule 1 (ICAM1), interleukin (IL)6, CXC motif chemokine ligand 8 (CXCL8), cyclin dependent kinase 1 and CD44 molecule (CD44) were significantly differentially expressed in prostate cancer tissues compared with healthy tissues based on The Cancer Genome Atlas data. The Gene Expression Profiling Interactive Analysis database revealed that ICAM1 was positively associated with IL6 and CXCL8, and epidermal growth factor receptor was positively associated with CD44 and SYK. Additionally, ten hub genes, which were identified to be associated with the drug resistance of docetaxel in prostatic carcinoma in the present study, were predominantly associated with tumor progression and metastasis. Reverse transcription-quantitative PCR analysis performed on docetaxel-sensitive and docetaxel-resistant prostate cancer cell lines demonstrated that certain hub genes, including CDK1, 2′-5′-oligoadenylate synthetase 3, CXCL8 and CDH1, were highly expressed in the docetaxel-resistant cell lines, which confirmed the bioinformatics results. In conclusion, the present study identified a number of important genes that are associated with the molecular mechanism of docetaxel resistance by integrated bioinformatical analysis, and these genes and regulatory networks may assist with identifying potential gene therapy targets for CRPC. Further functional analyses are required to validate the current findings.

Gene expression profiling of triple-negative breast tumors with different expression of secreted protein acidic and cysteine rich (SPARC)

Aim: To determine the expression signature of triple-negative breast cancer (TNBC) with differences of secreted protein acidic and rich in cysteine expression and clinical behavior. Patients, materials & methods: cDNA microarray analysis was performed to determine the expression profiling of TNBC, characterized regarding secreted protein acidic and rich in cysteine expression status. Immunohistochemistry analysis on tissue microarrays containing an independent cohort of TNBC was performed for validation. Results: Negative staining of SOHLH2 and positive staining of DNAJC12 and LIM1 was correlated with a poor outcome of the patients. Conclusion: Our findings provide new information on transcriptome changes associated with the clinical behavior of TNBC that may serve as a potential tool for the identification and characterization of new candidate biomarkers.