Screening of biomarkers for prediction of response to and prognosis after chemotherapy for breast cancers

Identification of common genes and pathways underlying imatinib and nilotinib treatment in CML: a Bioinformatics Study

Imatinib (IMA) and nilotinib are the first and second generations of BCR-ABL tyrosine kinase inhibitors, which widely applied in chronic myeloid leukemia (CML) treatment. Here we aimed to provide new targets for CML treatment by transcriptome analysis. Microarray data GSE19567 was downloaded and analyzed from Gene Expression Omnibus (GEO) to identify common genes, which are downregulated or upregulated in K562-imatinib and K562-nilotinib treated cells. The differentially expressed genes (DEGs) were assessed, and STRING and Cytoscape were used to create the protein-protein interaction (PPI) network. In imatinib and nilotinib treated groups' comparison, there were common 626 upregulated and 268 downregulated genes, which were differentially expressed. The GO analysis represented the enrichment of DEGs in iron ion binding, protein tyrosine kinase activity, transcription factor activity, ATP binding, sequence-specific DNA binding, cytokine activity, the mitochondrion, sequence-specific DNA binding, plasma membrane and cell-cell adherens junction. KEGG pathway analysis revealed that downregulated DEGs were associated with pathways including microRNAs in cancer and PI3K-Akt signaling pathway. Furthermore, upregulated DEGs were involved in hematopoietic cell lineage, lysosome and chemical carcinogenesis. Among the upregulated genes, MYH9, MYH14, MYL10, MYL7, MYL5, RXRA, CYP1A1, FECH, AKR1C3, ALAD, CAT, CITED2, CPT1A, CYP3A5, CYP3A7, FABP1, HBD, HMBS and PPOX genes were found as hub genes. Moreover, 20 downregulated genes, YARS, AARS, SARS, GARS, CARS, IARS, RRP79, CEBPB, RRP12, UTP14A, PNO1, CCND1, DDX10, MYC, WDR43, CEBPG, DDIT3, VEGFA, PIM1 and TRIB3 were identified as hub genes. These genes have the potential to become target genes for diagnosis and therapy of CML patients.

Identification of co-regulated genes associated with doxorubicin resistance in the MCF-7/ADR cancer cell line

Introduction

The molecular mechanism of chemotherapy resistance in breast cancer is not well understood. The identification of genes associated with chemoresistance is critical for a better understanding of the molecular processes driving resistance.

Methods

This study used a co-expression network analysis of Adriamycin (or doxorubicin)-resistant MCF-7 (MCF-7/ADR) and its parent MCF-7 cell lines to explore the mechanisms of drug resistance in breast cancer. Genes associated with doxorubicin resistance were extracted from two microarray datasets (GSE24460 and GSE76540) obtained from the Gene Expression Omnibus (GEO) database using the GEO2R web tool. The candidate differentially expressed genes (DEGs) with the highest degree and/or betweenness in the co-expression network were selected for further analysis. The expression of major DEGs was validated experimentally using qRT-PCR.

Results

We identified twelve DEGs in MCF-7/ADR compared with its parent MCF-7 cell line, including 10 upregulated and 2 downregulated DEGs. Functional enrichment suggests a key role for RNA binding by IGF2BPs and epithelial-to-mesenchymal transition pathways in drug resistance in breast cancer.

Discussion

Our findings suggested that MMP1, VIM, CNN3, LDHB, NEFH, PLS3, AKAP12, TCEAL2, and ABCB1 genes play an important role in doxorubicin resistance and could be targeted for developing novel therapies by chemical synthesis approaches.

NFYA promotes malignant behavior of triple-negative breast cancer in mice through the regulation of lipid metabolism

Two splicing variants exist in NFYA that exhibit high expression in many human tumour types. The balance in their expression correlates with prognosis in breast cancer, but functional differences remain unclear. Here, we demonstrate that NFYAv1, a long-form variant, upregulates the transcription of essential lipogenic enzymes ACACA and FASN to enhance the malignant behavior of triple-negative breast cancer (TNBC). Loss of the NFYAv1-lipogenesis axis strongly suppresses malignant behavior in vitro and in vivo, indicating that the NFYAv1-lipogenesis axis is essential for TNBC malignant behavior and that the axis might be a potential therapeutic target for TNBC. Furthermore, mice deficient in lipogenic enzymes, such as Acly, Acaca, and Fasn, exhibit embryonic lethality; however, Nfyav1-deficient mice exhibited no apparent developmental abnormalities. Our results indicate that the NFYAv1-lipogenesis axis has tumour-promoting effects and that NFYAv1 may be a safe therapeutic target for TNBC.

LSM3, NDUFB3, and PTGS2 may be potential biomarkers for BRCA1-mutation positive breast cancer

Purpose: We aimed to find critical biomakers associated with BRCA1-mutation positive breast cancer.

Methods: The data set E-MTAB-982 was downloaded from ArrayExpress database and the data were preprocessed using R package Oligo. Differential expression analysis between BRCA1-mutation positive breast cancer patients and BRCA1-mutation positive healthy subjects were performed using limma package. Then, gene set enrichment analysis was conducted. We constructed the network for BRCA1, its related differentially expressed genes (DEGs), and the enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. After that, survival analysis was performed based on the clinical data of breast cancer in TCGA database. Finally, box diagram for key genes was drawn.

Results: The network showed that LSM3, NDUFB3, GNPDA2, and PTGS2 were BRCA1 related DEGs. Furthermore, LSM3 was mainly enriched in RNA degradation pathway and spliceosome pathway. PTGS2 was enriched in arachidonic acid metabolism and VEGF signaling pathway. Survival analysis indicated that high expression of LSM3 indicated a poor prognosis of BRCA1-mutant breast cancer. Besides, box diagram showed that LSM3 was down-regulated in BRCA1-mutation positive breast cancer patients compared with that in BRCA1-mutation positive healthy subjects.

Conclusions: LSM3, NDUFB3, and PTGS2 may be biomarkers in BRCA1-mutant breast cancer, and high expression of LSM3 may indicate a poor prognosis of BRCA1-mutant breast cancer.

Analysis of Differentially Expressed Long Non-coding RNAs and the Associated TF-mRNA Network in Tongue Squamous Cell Carcinoma

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) play crucial roles in tongue squamous cell carcinoma (TSCC) tumorigenesis. However, the comprehensive regulation of lncRNAs-transcription factors (TFs)-messenger RNAs (mRNAs) in TSCC remains largely unknown. The purpose of this study was to identify aberrantly expressed lncRNAs and the associated TF-mRNA network in TSCC. To explore lncRNA and mRNA expression profiles and their biological functions in TSCC, we surveyed the lncRNA and mRNA expression profiles of TSCC and adjacent tissues using next-generation RNA sequencing in six patients. Thousands of significantly differentially expressed lncRNAs (DELs) and mRNAs (DEGs) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to demonstrate the principal functions of the significantly dysregulated lncRNAs and genes. A total of 40 DELs were screened between TSCC and adjacent non-cancerous tissues. Results obtained from GEPIA and StarBase confirmed the expression levels of nine pivotal DELs obtained in our study. Three of the nine deregulated DELs were identified to have a significant impact on the overall survival of TSCC patients, which were evaluated with GEPIA and StarBase. LncMAP was used to predict the lncRNA-TF-mRNA triplets in TSCC. Furthermore, based on these results, we established lncRNA-TF-mRNA coexpression networks for the up- and downregulated lncRNAs using Cytoscape. We also found that among the nine pivotal lncRNAs, there is limited research on the abnormally expressed lncRNAs, including RP11-54H7.4, CTD-2545M3.8, RP11-760H22.2, RP4-791M13.3, and LINC01405, in TSCC pathogenesis. This is the first study to show that RP11-54H7.4, LINC00152, and LINC01405 can be acted as a prognostic target for TSCC. Our findings provide a novel perspective and lay the foundation for future research on the potential roles of lncRNAs, TFs, and mRNAs in TSCC. Verification of the potential lncRNA-TF-mRNA regulatory networks will provide a more comprehensive understanding of the pathogenesis of TSCC.

Integrated pan-cancer gene expression and drug sensitivity analysis reveals SLFN11 mRNA as a solid tumor biomarker predictive of sensitivity to DNA-damaging chemotherapy

Background

Precision oncology seeks to integrate multiple layers of data from a patient’s cancer to effectively tailor therapy. Conventional chemotherapies are sometimes effective but accompanied by adverse events, warranting the identification of a biomarker of chemosensitivity.

Objective

Identify an mRNA biomarker that predicts chemosensitivity across solid tumor subtypes.

Methods

We performed a pan-solid tumor analysis integrating gene expression and drug sensitivity profiles from 3 cancer cell line datasets to identify transcripts correlated with sensitivity to a panel of chemotherapeutics. We then tested the ability of an mRNA biomarker to predictive clinical outcomes in cohorts of patients with breast, lung, or ovarian cancer.

Results

Expression levels of several mRNA transcripts were significantly correlated with sensitivity or resistance chemotherapeutics in cancer cell line datasets. The only mRNA transcript significantly correlated with sensitization to multiple classes of DNA-damaging chemotherapeutics in all 3 cell line datasets was encoded by Schlafen Family Member 11 (SLFN11). Analyses of multiple breast, lung, and ovarian cancer patient cohorts treated with chemotherapy confirmed SLFN11 mRNA expression as a predictive biomarker of longer overall survival and improved tumor response.

Conclusions

Tumor SLFN11 mRNA expression is a biomarker of sensitivity to an array of DNA-damaging chemotherapeutics across solid tumor subtypes.

Overexpression and alternative splicing of NF-YA in breast cancer

NF-Y is a CCAAT-binding trimeric transcription factor, whose regulome, interactome and oncogenic potential point to direct involvement in cellular transformation. Yet little is known about the levels of NF-Y subunits in tumors. We focused on breast carcinomas, and analyzed RNA-Seq datasets of TCGA and 54 BRCA cell lines at gene and isoforms level. We partitioned all tumors in the four major subclasses. NF-YA, but not histone-fold subunits NF-YB/NF-YC, is globally overexpressed, correlating with the proliferative Ki67 marker and a common set of 840 genes, with cell-cycle, metabolism GO terms. Their promoters are enriched in NF-Y, GC-rich and E2F sites. Surprisingly, there is an isoform switch, with the “short” isoform -NF-YAs- becoming predominant in tumors. E2F genes are also overexpressed in BRCA, but no switch in isoforms is observed. In Basal-like Claudin^low cell lines and tumors, expression of NF-YAl -long- isoform is high, together with 11 typical EMT markers and low levels of basal Keratins. Analysis of Progression-Free-Intervals indicates that tumors with unbalance of NF-YA isoforms ratios have worst clinical outcomes. The data suggest that NF-YA overexpression increases CCAAT-dependent, pro-growth genes in BRCA. NF-YAs is associated with a proliferative signature, but high levels of NF-YAl signal loss of epithelial features, EMT and acquisition of a more aggressive behavior in a subset of Claudin^low Basal-like tumors.

The animal nuclear factor Y: an enigmatic and important heterotrimeric transcription factor

Nuclear factor Y (NF-Y) is a heterotrimeric transcription factor with the ability to bind to CCAAT boxes in nearly all eukaryotes and has long been a topic of interest since it is first identified. In plants, due to each subunit of NF-Y is encoded by multiple gene families, there are a wide variety NF-Y complex combinations that fulfill many pivotal functions. However, the animal NF-Y complex usually has only one type of combination, as each subunit is generally encoded by a single gene. Even though, mounting evidence points to that the animal NF-Y complex is also essential for numerous biological processes involved in proliferation and apoptosis, cancer and tumor, stress responses, growth and development. Therefore, a relatively comprehensive functional dissection of animal NF-Y will enable a deeper comprehension of how lesser combinations of the NF-Y complex regulate diverse aspects of biology processes in animal. Here, we focus mainly on reviewing recent advances related to NF-Y in the animal field, including subunit structural characteristics, expression regulation models and biological functions, and we also discuss future directions.