Oleuropein inhibits migration ability through suppression of epithelial-mesenchymal transition and synergistically enhances doxorubicin-mediated apoptosis in MCF-7 cells

Distinct metastasis is one of the main causes of breast cancer (BC)-related mortality and epithelial-mesenchymal transition (EMT) is a primary step in metastasis dissemination. On the other hand, doxorubicin (DOX) is an effective chemotherapeutic agent against BC; unfortunately, its clinical use is limited by dose-dependent side effects. Therefore, extensive efforts have been dedicated to suppressing metastasis of BC and also to overcome DOX side effects together with keeping its antitumor efficacy. Studies supported the role of oleuropein (OLEU) in reducing DOX-induced side effects besides its antitumor actions. In this study, the antimigratory effect of OLEU was assessed and real-time PCR (RT-PCR) was used to detect OLEU effect on the expression level of EMT markers, in MCF-7 cells. The cytotoxic effect of OLEU and DOX was assessed by MTT assay, whereas the ratio of apoptosis was investigated by flow cytometry. The results showed that migration ability of MCF-7 cells remarkably decreased in OLEU treated group and RT-PCR results showed that OLEU may exert its antimigratory action by suppressing EMT through downregulation of sirtuin1 (SIRT1). Also, the results indicated that both OLEU and DOX were cytotoxic to MCF-7 cells, whereas DOX-OLEU cotreatment led to additive cytotoxicity and apoptosis rate. This study provides evidence regarding the suppressive role of OLEU on MCF-7 cells migration ability through suppression of EMT, and for the first time, it was proposed that SIRT1 downregulation can be involved in the OLEU antimigratory effect. Also, the findings demonstrated that OLEU can reduce DOX-induced side effects by reducing its effective dose.     

AZGP1 is androgen responsive and involved in AR-induced prostate cancer cell proliferation and metastasis

Alpha-2-glycoprotein 1, zinc-binding (AZGP1), known as zinc-alpha-2-glycoprotein (ZAG), is a multifunctional secretory glycoprotein and relevant to cancer metastasis. Little is known regarding the underlying mechanisms of AZGP1 in prostate cancer (PCa). In the present study, we report that AZGP1 is an androgen-responsive gene, which is involved in AR-induced PCa cell proliferation and metastasis. In clinical specimens, the expression of AZGP1 in PCa tissues is markedly higher than that in adjacent normal tissues. In cultures, expression of AZGP1 is upregulated by the androgen-AR axis at both messenger RNA and protein levels. Furthermore, Chip-Seq assay identifies canonical androgen-responsive elements (AREs) at AZGP1 enhancer; and dual-luciferase reporter assays reveal that the AREs is highly responsive to androgen whereas mutations of the AREs abolish the reporter activity. In addition, AZGP1 promotes G1/S phase transition and cell cycle progress by increasing cyclin D1 levels in PCa cells. Functional studies demonstrate that knocking down endogenous AZGP1 expression in LNCaP and CWR22Rv1 cells largely weaken androgen/AR axis-induced cell migration and invasion. In vivo xenotransplantation tumor experiments also show that AZGP1 involves in androgen/AR axis-mediated PCa cell proliferation. Taken together, our study implicates for the first time that AZGP1 is an AR target gene and is involved in androgen/AR axis-mediated cell proliferation and metastasis in primary PCa.     

Evidence for calpains in cancer metastasis

Metastatic dissemination represents the final stage of tumor progression as well as the principal cause of cancer-associated deaths. Calpains are a conserved family of calcium-dependent cysteine proteinases with ubiquitous or tissue-specific expression. Accumulating evidence indicates a central role for calpains in tumor migration and invasion via participating in several key processes, including focal adhesion dynamics, cytoskeletal remodeling, epithelial-to-mesenchymal transition, and apoptosis. Activated after the increased intracellular calcium concentration () induced by membrane channels and extracellular or intracellular stimuli, calpains induce the limited cleavage or functional modulation of various substrates that serve as metastatic mediators. This review covers established literature to summarize the mechanisms and underlying signaling pathways of calpains in cancer metastasis, making calpains attractive targets for aggressive tumor therapies.     

microRNA-329 suppresses epithelial-to-mesenchymal transition and lymph node metastasis in bile duct cancer by inhibiting laminin subunit beta 3

Bile duct cancer (BDC), also known as cholangiocarcinoma, is a highly desmoplastic cancer with a growth pattern characterized by periductal extension and infiltration. Studies have suggested that microRNAs (miRNAs) play an important role in BDC progression. Here we aim at investigating the effects of miR-329 on BDC development, focusing especially on epithelial-to-mesenchymal transition (EMT) in vitro and lymph node metastasis in vivo. Expression microarrays associated with BDC tissues were collected and differentially expressed genes were analyzed, followed by miRNA target prediction and verification. The role miR-329 played in BDC was examined using gain-of-function and loss-of-function methods. The expressions of miR-329, laminin subunit beta 3 (LAMB3), and EMT markers, in addition to cell proliferation, migration, and invasion were evaluated. Furthermore, nude mice models of BDC were established to observe tumor growth and metastatic lymph nodes. The LAMB3 was identified as an upregulated gene based on the GSE77984 and GSE45001 microarray analysis. LAMB3 was also predicted and confirmed to be a target gene of miR-329 by dual-luciferase reporter assay. Through further cell experiments, the EMT process was reversed, cell proliferation, invasion, and migration were suppressed, when miR-329 was upregulated. Furthermore, in vivo experiments exhibited that the overexpression of miR-329 inhibited tumor growth and the number of metastatic lymph nodes. This study provides in vivo and in vitro evidence that miR-329 inhibits BDC progression through translational repression of LAMB3. Therefore, the obtained results may aid as an experimental basis for improving prognosis of BDC.     

Long noncoding RNA PTPRG-AS1 acts as a microRNA-194-3p sponge to regulate radiosensitivity and metastasis of nasopharyngeal carcinoma cells via PRC1

Protein regulator of cytokinesis 1 (PRC1) has been reported in correlation with various malignancies. Functionality of PRC1 in nasopharyngeal carcinoma (NPC) was investigated, in perspective of long noncoding RNA (lncRNA) regulatory circuitry. Aberrant expressed messenger RNA and lncRNA were screened out from the Gene Expression Omnibus microarray database. NPC cell line CNE-2 was adopted for in vitro study and transfected with mimic or short hairpin RNA of miR-194-3p and PTPRG-AS1. The radioactive sensitivity, cell viability, migration, invasion, and apoptosis were detected. PTPRG-AS1 and PRC1 were upregulated in NPC, whereas miR-194-3p was downregulated. PTPRG-AS1 was found to specifically bind to miR-194-3p as a competing endogenous RNA and miR-194-3p targets and negatively regulates PRC1. Overexpressed miR-194-3p or silenced PTPRG-AS1 resulted in enhanced sensitivity to radiotherapy and cell apoptosis along with suppressed cell migration, invasion and proliferation in NPC. Furthermore, impaired tumor formation was also caused by miR-194-3p overexpression or PTPRG-AS1 suppression through xenograft tumor in nude mice. In our study, PTPRG-AS1/miR-194-3p/PRC1 regulatory circuitry was revealed in NPC, the mechanism of which can be of clinical significance for treatment of NPC.     

Upregulation of lncRNA GAS5 inhibits the growth and metastasis of cervical cancer cells

This study aims to figure out the methylation of long non-coding RNA GAS5 promoter in cervical cancer and the mechanism of GAS5 on the progression of cervical cancer cells. The expression of GAS5 and methylation state of GAS5 in cervical cancer tissues and cells were determined. With the aim to to explore the ability of GAS5 in the proliferation, cell cycle progression, apoptosis, invasion, migration as well as the tumor growth, and metastasis in nude mice were determined. The expression of GAS5 was decreased and methylation state of GAS5 was elevated in cervical cancer. Overexpression of GAS5 inhibited proliferation, cell cycle progression, invasion, migration while inducing apoptosis of cervical cancer cells as well as suppressed tumor growth and metastasis in nude mice. Our study demonstrates that abnormal methylation of GAS5 contributes to poor expression of GAS5 in cervical cancer. In addition, upregulation of GAS5 inhibits the cervical cancer development.     

High expression of LASS2 is associated with unfavorable prognosis in patients with ovarian cancer

Homo sapiens longevity assurance homolog 2 of yeast LAG1 (LASS2), is a gene isolated from a human liver complementary DNA library. In this study, we found that LASS2 protein level was positively related to International Federation of Gynecology and Obstetrics (FIGO) stage and LASS2-negative tumors showed significant association with longer disease-free survival (DFS) and overall survival (OS) in ovarian cancer patients. The heterogeneous expression of LASS2 had been exhibited in diverse ovarian cancer cells. A significantly lower messenger RNA (mRNA) and protein level of LASS2 was seen in 3AO cell compared with those in other types of ovarian cancer cells. Meanwhile, the mRNA and protein levels of LASS2 in ES-2 and NIH:OVCAR-3 cells were obviously higher. LASS2 overexpression in 3AO cell could promote migration, invasion, and metastasis abilities in vitro and in vivo, while LASS2 knockdown in ES-2 and NIH:OVCAR-3 cells had the opposite effects. The oncogenic capacity of LASS2 in ovarian cancer may be mediated by increased expression of YAP/TAZ. It is indicated that lowering the expression of LASS2 is likely to serve as an unprecedented approach for the treatment of ovarian cancer.     

The role of microRNAs regulating the expression of matrix metalloproteinases (MMPs) in breast cancer development,progression, and metastasis

MicroRNAs (miRNAs) regulate several biological and physiological processes in mammalian cells, including cellular proliferation, differentiation, apoptosis, and metabolism. Recent studies have confirmed the alteration of them during the cancer development. Matrix metalloproteinases (MMPs), belonging to the large family of proteases, have also been demonstrated to play crucial roles in tissue remodeling, and to support cancer progression and metastasis. There are several known miRNAs which regulate the MMP family and their expression. The expression profiles of miRNAs involved in MMP regulation, change during cancer progression, and metastasis. The present review focuses on important miRNAs capable of targeting MMPs through direct and indirect interactions during the breast cancer development, progression, and metastasis.     

PKM2-regulated STAT3 promotes esophageal squamous cell carcinoma progression via TGF-β1-induced EMT

Recent studies have demonstrated pleiotropic roles of pyruvate kinase isoenzyme type M2 (PKM2) in tumor progression. However, the precise mechanisms underlying the effects of PKM2 on esophageal squamous cell carcinoma (ESCC) metastasis and transforming growth factor β1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) remain to be established. In this study, we observed upregulation of PKM2 in ESCC tissues that was markedly associated with lymph node metastasis and poor prognosis. High PKM2 expression in tumor tissues frequently coincided with the high pSTAT3Tyr705 expression and low E-cadherin expression. Furthermore, altered PKM2 expression was significantly associated with proliferation, migration, and invasion of ESCC cells, in addition to expression patterns of EMT markers (Snail, E-cadherin, and vimentin) and pSTAT3^Tyr705/STAT3 ratio. Overexpression of STAT3 significantly attenuated the effects of PKM2 knockdown on cell proliferation and motility as well as expression of pSTAT3 ^Tyr705 and EMT markers. Consistently, stable short hairpin RNA (shRNA)-mediated silencing of PKM2 reversed the effects of TGF-β1 treatment, specifically, upregulation of PKM2, phosphorylation of STAT3 at Tyr705, and increased EMT, migration, and invasion. We propose that PKM2 regulates cell proliferation, migration, and invasion via phosphorylation of STAT3 through TGF-β1-induced EMT. Our findings collectively provide mechanistic insights into the tumor-promoting role of PKM2, supporting its prognostic value and the therapeutic utility of PKM2 inhibitors as potential antitumor agents in ESCC.     

Imaging the interaction of αv integrin-GFP in osteosarcoma cells with RFP-expressing host stromal cells and tumor-scaffold collagen in the primary and metastatic tumor microenvironment

Human osteosarcoma 143B cells were previously stably transfected with an α_v integrin green flourescent protein (GFP) vector. 143B cells expressing α_v integrin-GFP were transplanted orthotopically in the tibia of transgenic nude mice ubiquitously expressing red fluorescent protein (RFP). The primary tumors acquired RFP-expressing stroma and were passaged orthotopically in the tibia in noncolored nude mice, which maintained the RFP stroma. The interaction of α_v integrin-GFP expression in 143B cells with RFP-expressing host stromal cells was observed by confocal microscopy using the Olympus FV1000. Collagen fibers were imaged simultaneously in reflectance mode. The RFP-expressing stroma included cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs) which persisted even 3 weeks after passage to nontransgenic nude mice. CAFs expressing RFP were aligned between collagen fibers and cancer cells expressing α_v integrin-GFP. Six weeks after transplantation, pulmonary metastases expressing α_v integrin-GFP could be identified. TAMs expressing RFP accompanied metastasized osteosarcoma cells expressing α_v integrin-GFP in the lung. The current study demonstrates the importance of α_v integrin interaction with stromal elements in osteosarcoma.