The N-terminal polypeptide derived from viral macrophage inflammatory protein II reverses breast cancer epithelial-to-mesenchymal transition via a PDGFRα-dependent mechanism

Cancer stem cell-mediated drug resistance: A comprehensive gene expression profile analysis in breast cancer

Breast cancer is the most frequently diagnosed malignancy in women and a major public health concern. In the current report, differential expression of the breast cancer resistance promoting genes with a focus on breast cancer stem cell related elements as well as the correlation of their mRNAs with various clinicopathologic characteristics, including molecular subtypes, tumor grade/stage, and methylation status, have been investigated using METABRIC and TCGA datasets. To achieve this goal, we downloaded gene expression data of breast cancer patients from TCGA and METABRIC. Then, statistical analyses were used to assess the correlation between the expression levels of stem cell related drug resistant genes and methylation status, tumor grades, various molecular subtypes, and some cancer hallmark gene sets such as immune evasion, metastasis, and angiogenesis. According to the results of this study, a number of stem cell related drug resistant genes are deregulated in breast cancer patients. Furthermore, we observe negative correlations between methylation of resistance genes and mRNA expression. There is a significant difference in the expression of resistance-promoting genes between different molecular subtypes. As mRNA expression and DNA methylation are clearly related, DNA methylation might be a mechanism that regulates these genes in breast cancer cells. As indicated by the differential expression of resistance-promoting genes among various breast cancer molecular subtypes, these genes may function differently in different subtypes of breast cancer. In conclusion, significant deregulation of resistance-promoting factors indicates that these genes may play a significant role in the development of breast cancer.

Identified the novel resistant biomarkers for taxane-based therapy for triple-negative breast cancer

Developing treatment strategies for triple-negative breast cancer (TNBC) has become an important clinical challenge. Currently, taxane-based chemotherapy is one of the standard treatments for TNBC. However, determining the key factor of taxane-resistance is urgently in need for clinical treatment for breast cancer. We used GEO data to generate paclitaxel resistance in two basal-like TNBC cell lines (SUM149 and MDA-MB-468). Seventy-one common upregulated differentially expressed genes (DEGs) and 11 downregulated DEGs were found to be related to paclitaxel resistance. By constructing protein-protein interactions, 28 hub proteins with a degree cutoff criterion of ≥1 were found. Nine hub genes (COL4A6, COL4A5, IL6, PDGFA, LPAR1, FYB, IL20, IL18R1 and INHBA) are involved in important signaling pathways. We found that upregulated PDGFA and downregulated COL4A6 were significantly associated with an insensitive response to neoadjuvant paclitaxel-based therapy. A Kaplan-Meier plot was created to check the prognostic values of 11 hub DEGs in terms of recurrence-free survival. High expressions of PDGFA and LAMB3 were correlated with poor recurrence-free survival, while low levels of FYB, IL18R1, and RASGRP1 indicated poorer relapse-free survival. Our results suggest that PDGFA, COL4A6, LPAR1, FYB, COL4A5, and RASGRP1 might be candidate target genes for taxane-based therapy in basal-like TNBC.

The Signaling Duo CXCL12 and CXCR4: Chemokine Fuel for Breast Cancer Tumorigenesis

Simple Summary

Breast cancer remains the most common malignancy in women. In this review, we explore the role of the CXCL12/CXCR4 pathway in breast cancer. We show that the CXCL12/CXCR4 cascade is involved in nearly every aspect of breast cancer tumorigenesis including proliferation, cell motility and distant metastasis. Moreover, we summarize current knowledge about the CXCL12/CXCR4-targeted therapies. Due to the critical roles of this pathway in breast cancer and other malignancies, we believe that audiences in different fields will find this overview helpful.

Abstract

The CXCL12/CXCR4 signaling pathway has emerged in the recent years as a key player in breast cancer tumorigenesis. This pathway controls many aspects of breast cancer development including cancer cell proliferation, motility and metastasis to all target organs. Moreover, the CXCL12/CXCR4 cascade affects both immune and stromal cells, creating tumor-supporting microenvironment. In this review, we examine state-of-the-art knowledge about detrimental roles of the CXCL12/CXCR4 signaling, discuss its therapeutic potential and suggest further research directions beneficial both for basic research and personalized medicine in breast cancer.

The N-terminal polypeptide derived from vMIP-II exerts its antitumor activity in human breast cancer through CXCR4/miR-7-5p/Skp2 pathway

Breast cancer is a malignant tumor with the highest incidence in women of the world. CXCR4 and Skp2 are highly expressed in breast cancer cells and CXCR4 was positively correlated with Skp2 by interference or overexpression. The microRNA array was used to detect the differentially expressed spectrum of micro RNAs in breast cancer cells the changes of miR-7-5p after CXCR4 inhibitor (NT21MP) treatment to block the CXCR4/SDF-1 pathway was founded. MiR-7-5p has been found to be correlated with Skp2 in various tumors in the literature, and Skp2 expression can be regulated by transfection with miR-7-5p mimics or inhibitors. The expression level of miR-7-5p was upregulated or downregulated after CXCR4 interference or overexpression. Combined with the correlation between CXCR4 and miR-7-5p in the chip results, CXCR4 may regulate Skp2 through miR-7-5p. Epithelial cells have the morphological characteristics of mesenchymal cells for some reason called epithelial-mesenchymal transformation (EMT). Transfection of miR-7-5p mimics into drug-resistant cells reduced Skp2 levels, decreased the expression of Vimentin, Snail, and slug, and increased the expression of E-cadherin. CXCR4 inhibitor (NT21MP) can reverse the EMT changes caused by miR-7-5p inhibitor. Similarly, in vivo results suggesting that CXCR4 inhibitors can reverse the EMT phenotype of drug-resistant breast cancer cells through the CXCR4/miR-7-5p/Skp2 pathway. In summary, the CXCR4/miR-7-5p/Skp2 signaling pathway plays an important role in the progression of breast cancer. This study provides a theoretical basis for the treatment of breast cancer by targeting the CXCR4 pathway.

The N-terminal polypeptide derived from vMIP-II exerts its anti-tumor activity in human breast cancer by regulating lncRNA SPRY4-IT1

Accumulating evidence demonstrates that long non-coding RNA (lncRNA) sprouty4-intron transcript 1 (lncRNA SPRY4-IT1) plays a vital role in the development of breast cancer. However, the underlying mechanism has not been eventually illuminated. We aimed to explore the biological activity of lncRNA SPRY4-IT1 in breast cancer cells and whether N-terminal polypeptide derived from viral macrophage inflammatory protein II (NT21MP) could exert its anti-tumor effect by regulating lncRNA SPRY4-IT1 and its target gene SKA2 Real-time RT-PCR, Western blotting, wound healing, and invasion assays were used to achieve this goal. We found that lncRNA SPRY4-IT1 was highly expressed in breast cancer cells. Moreover, NT21MP markedly inhibited biological effects of breast cancer cells by regulating lncRNA SPRY4-IT1, which was partially achieved through SKA2. Our findings suggested that lncRNA SPRY4-IT1 could serve as a novel biomarker by NT21MP for breast cancer.

NT21MP negatively regulates paclitaxel-resistant cells by targeting miR‑155‑3p and miR‑155-5p via the CXCR4 pathway in breast cancer

Evidence has shown that microRNAs (miRNAs) are vital in cell growth, migration, and invasion by inhibiting their target genes. A previous study demonstrated that miRNA (miR)-155-3p and miR-155-5p exerted opposite effects on cell proliferation, apoptosis, migration and invasion in breast cancer cell lines. An miRNA microarray was used to show that miR-155-3p was downregulated whereas miR-155-5p was upregulated in paclitaxel-resistant (PR) cells compared with parental breast cancer cells. However, the role of miR-155 in breast cancer cell invasion and metastasis remains to be elucidated. A 21-residue peptide derived from the viral macrophage inflammatory protein II (NT21MP), competes with the ligand of CXC chemokine receptor 4 (CXCR4) and its ligand stromal cell-derived factor-1α, inducing cell apoptosis in breast cancer. The present study aimed to identify the underlying mechanism of action of miR-155-3p/5p and NT21MP in PR breast cancer cells. Quantitative polymerase chain reaction, western blotting, wound-healing, cell cycle and apoptosis assays, and Cell Counting kit-8 assay were used to achieve this goal. The combined overexpression of miR-155-3p with NT21MP decreased the migration and invasion ability and increased the number of apoptotic and arrested cells in the G0/G1 phase transition in vitro. The knockdown of miR-155-5p combined with NT21MP had a similar effect on PR breast cancer cells. Furthermore, the ectopic expression of their target gene myeloid differentiation primary response gene 88 (MYD88) or tumor protein 53-induced nuclear protein 1 (TP53INP1) combined with NT21MP enhanced the sensitivity of the breast cancer cells to paclitaxel. Taken together, these findings suggested that miR-155-3p/5p and their target genes MYD88 and TP53INP1 may serve as novel biomarkers for NT21MP therapy through the CXCR4 pathway for improving sensitivity to paclitaxel in breast cancer.

[CXC chemokine receptor 4 regulates breast cancer cell cycle through S phase kinase associated protein 2]

OBJECTIVE

To investigate the effect of CXC chemokine receptor 4 (CXCR4) on cell cycle of breast cancer and its molecular mechanisms.

METHODS

The expression of CXCR4 and S phase kinase associated protein 2 (Skp2) was detected by real-time fluorescence quantitative PCR (fqRT-PCR) and Western blot in breast cancer cells. The expression of signal proteins and the downstream genes of Skp2 was detected by Western blot. The effect of CXCR4, PI3K/Akt pathway inhibitor LY294002 and ERK pathway inhibitor U0126 on cell cycle of breast cancer was detected by propidium iodide staining.

RESULTS

Skp2 was significantly down-regulated in CXCR4-downregulated cells and up-regulated in CXCR4-upregulated cells. CXCR4 also regulated the expression of Skp2 and other downstream genes by signaling protein. The proportion of cells in G0/G1 phase increased and that in S phase declined in CXCR4-downregulated cell, and the effect was more significant when combined with the use of LY294002 or U0126.

CONCLUSIONS

CXCR4 can affect cell cycle and inhibit the proliferation of breast cancer cells by regulating Skp2 gene expression through PI3K/Akt and ERK signaling pathway.