Circular RNAs: Novel Players in the Oxidative Stress-Mediated Pathologies, Biomarkers, and Therapeutic Targets.

Oxidative stress (OxS) is a wildly described cause of damage to macromolecules, resulting in abnormal physiological conditions. In recent years, a few studies have shown that oxidation/antioxidation imbalance plays a significant role in developing diseases involving different systems and organs. However, the research on the circular RNA (circRNA) roles in OxS is still in its very infancy. Therefore, we hope to provide a comprehensive overview of the recent research that explored the function of circRNAs associated with OxS and its role in the pathogenesis of different diseases that affect different body systems like the nervous system, cardiovascular system, kidneys, and lungs. It provides the possibilities of using these circRNAs as superior diagnostic and therapeutic options for OxS associated with these disease conditions.

Microvesicle-Mediated Delivery of Minicircle DNA Results in Effective Gene-Directed Enzyme Prodrug Cancer Therapy.

An emerging approach for cancer treatment employs the use of extracellular vesicles, specifically exosomes and microvesicles, as delivery vehicles. We previously demonstrated that microvesicles can functionally deliver plasmid DNA to cells and showed that plasmid size and sequence, in part, determine the delivery efficiency. In this study, delivery vehicles comprised of microvesicles loaded with engineered minicircle (MC) DNA that encodes prodrug converting enzymes developed as a cancer therapy in mammary carcinoma models. We demonstrated that MCs can be loaded into shed microvesicles with greater efficiency than their parental plasmid counterparts and that microvesicle-mediated MC delivery led to significantly higher and more prolonged transgene expression in recipient cells than microvesicles loaded with the parental plasmid. Microvesicles loaded with MCs encoding a thymidine kinase (TK)/nitroreductase (NTR) fusion protein produced prolonged TK-NTR expression in mammary carcinoma cells. In vivo delivery of TK-NTR and administration of prodrugs led to the effective killing of both targeted cells and surrounding tumor cells via TK-NTR-mediated conversion of codelivered prodrugs into active cytotoxic agents. In vivo evaluation of the bystander effect in mouse models demonstrated that for effective therapy, at least 1% of tumor cells need to be delivered with TK-NTR-encoding MCs. These results suggest that MC delivery via microvesicles can mediate gene transfer to an extent that enables effective prodrug conversion and tumor cell death such that it comprises a promising approach to cancer therapy.

Inflammatory breast cancer: Activation of the aryl hydrocarbon receptor and its target CYP1B1 correlates closely with Wnt5a/b-ß-catenin signalling, the stem cell phenotype and disease progression.

The aim of the present study was to evaluate the expression levels of the aryl hydrocarbon receptor (AHR) and its target gene CYP1B1 and to correlate their expression with Wnt5a/b-ß-catenin, the CD44+/CD24(-/low) cancer stem cell (CSC) subset and factors associated with poor prognosis in inflammatory breast cancer (IBC) and non-IBC patients. The methods of analysis used were quantitative real-time PCR, western blotting, immunohistochemistry and flow cytometry. Compared to non-IBC tissues, IBC tissues exhibited the overexpression of AHR and its target gene/protein CYP1B1. AHR and CYP1B1 mRNA levels were associated with the poor clinical prognosis markers tumour grade, lymphovascular invasion, cell proliferation and lymph node metastasis. Furthermore, AHR expression correlated with the expression of Wnt5a/b and ß-catenin signalling molecules, and Wnt5a mRNA expression was downregulated in the SUM149 human IBC cell line and the MDA-MB-231 non-IBC cell line upon inhibition of AHR. AHR gene knockout (CRISPR-Cas9) inhibits CYP1B1 and Wnt5a expression in the IBC cell line. The CD44+/CD24(-/low) subset was significantly correlated with the expression of AHR, CYP1B1, Wnt5a/b and ß-catenin in IBC tissues. The overexpression of AHR and its target CYP1B1 correlated with the expression of Wnt5a/b and ß-catenin, CSCs, and poor clinical prognostic factors of IBC. Thus, targeting AHR and/or its downstream target molecules CYP1B1 and Wnt5a/b may represent a therapeutic approach for IBC.

Anti-proliferative effect of chitosan nanoparticles (extracted from crayfish Procambarus clarkii, Crustacea: Cambaridae) against MDA-MB-231 and SK-BR-3 human breast cancer cell lines.

Actually, the most common cancer in women is the breast cancer which is the second most widespread cancer overall. In 2018, there were over two million new cases of women breast cancer. Particularly, we tried to extract chitosan from crayfish Procambarus clarkii, Crustacea: Cambaridae, by N-deacetylation of chitin. The chemical structure of chitosan was characterized by Fourier transform infrared (FT-IR) spectroscopy. Also DDA was calculated from FT-IR and ultraviolet spectrophotometry data. Chitosan nanoparticles were prepared using a ball-milling technique. The as-prepared chitosan nanoparticles were characterized by transmission electron microscopy, dynamic light scattering as well as zeta potential. The cytotoxicity of chitosan and its nanoparticles (50 and 100 µg/mL) against human breast cancer (SK BR3 and MDA-MB-231 cell lines) was evaluated. MTT assay asserts the significant inhibitory action of both chitosan and its nanoparticles on the proliferation of human breast cancer cells in vitro. Chitosan nanoparticles had more anti-proliferative effects on MDA-MB-231 and SK-BR-3 cell lines than its corresponding chitosan. Although, chitosan nanoparticles, that has higher DDA, had a higher cytotoxic activity against human breast cancer MDA-MB-231 and SK-BR-3 cell lines in vitro. Eventually, chitosan and its nanoparticles can be considered as a promising natural compounds in human breast cancer treatment.

Hormonal-receptor positive breast cancer: IL-6 augments invasion and lymph node metastasis via stimulating cathepsin B expression.

Hormonal-receptor positive (HRP) breast cancer patients with positive metastatic axillary lymph nodes are characterized by poor prognosis and increased mortality rate. The mechanisms by which cancer cells invade lymph nodes have not yet been fully explored. Several studies have shown that expression of IL-6 and the proteolytic enzyme cathepsin B (CTSB) was associated with breast cancer poor prognosis. In the present study, the effect of different concentrations of recombinant human IL-6 on the invasiveness capacity of HRP breast cancer cell line MCF-7 was tested using an in vitro invasion chamber assay. The impact of IL-6 on expression and activity of CTSB was also investigated. IL-6 treatment promoted the invasiveness potential of MCF-7 cells in a dose-dependent manner. Furthermore, MCF-7 cells displayed elevated CTSB expression and activity associated with loss of E-cadherin and upregulation of vimentin protein levels upon IL-6 stimulation. To validate these results in vivo, the level of expression of IL-6 and CTSB in the carcinoma tissues of HRP-breast cancer patients with positive and negative axillary metastatic lymph nodes (pLNs and nLNs) was assessed. Western blot and immunohistochemical staining data showed that expression of IL-6 and CTSB was higher in carcinoma tissues in HRP-breast cancer with pLNs than those with nLNs patients. ELISA results showed carcinoma tissues of HRP-breast cancer with pLNs exhibited significantly elevated IL-6 protein levels by approximately 2.8-fold compared with those with nLNs patients (P < 0.05). Interestingly, a significantly positive correlation between IL-6 and CTSB expression was detected in clinical samples of HRP-breast cancer patients with pLNs (r = 0.78, P < 0.01). Collectively, this study suggests that IL-6-induced CTSB may play a role in lymph node metastasis, and that may possess future therapeutic implications for HRP-breast cancer patients with pLNs. Further studies are necessary to fully identify IL-6/CTSB axis in different molecular subtypes of breast cancer.

Secretome of tumor-associated leukocytes augment epithelial-mesenchymal transition in positive lymph node breast cancer patients via activation of EGFR/Tyr845 and NF-κB/p65 signaling pathway.

Epithelial-mesenchymal transition (EMT) is an essential process in breast cancer metastasis. The aim of the present study was to determine the role of secretions of tumor-associated leukocytes (TALs) isolated from negative and positive lymph nodes (nLNs and pLNs, respectively) breast cancer patients in regulating EMT mechanism and the associated signaling pathways. We found an increased infiltration of TALs, which was associated with downregulation of E-cadherin and over-expression of vimentin in the breast carcinoma tissues of pLNs as compared to nLNs patients and normal breast tissues obtained from healthy volunteers during mammoplasty. Furthermore, TALs isolated from pLNs breast cancer patients secreted an elevated panel of cytokines by up to 2-5-fold when compared with those isolated from nLNs patients. Secretome of TALs of pLNs possessed higher TARC, IGF-1, IL-3, TNF-ß, IL-5, G-CSF, IL-4, and IL-1α with more than a fivefold compared to those of nLNs. Using the human breast cancer cell lines MCF-7 and MDA-MB-231, we found that cytokines secreted by TALs isolated from nLNs and pLNs breast cancer patients promoted EMT via upregulation of TGF-ß and vimentin and downregulation of E-cadherin at messenger RNA (mRNA) levels in both cell lines and at protein level in MCF-7. While TGF-ß is over-expressed by MDA-MB-231 seeded in media conditioned by secretome of TALs isolated from nLNs and pLNs breast cancer patients. The downstream TGF-ß signaling transcription factors, Snail, Slug, and Twist, known to be associated with EMT mechanism were over-expressed by MCF-7 and MDA-MB-231 seeded in media conditioned by secretome of TALs isolated from nLNs and pLNs breast cancer patients. Acquisition of EMT in MCF-7 cells is mechanistically attributed to the activation of EGFR(Tyr845) and NF-κB/p65(Ser276) signaling which are significantly highly expressed by MCF-7 cells seeded in media conditioned by secretome of TALs isolated from pLNs compared to nLNs patients. Overall, this study provides implications of secretome of TALs and activated EGFR(Tyr845) and NF-κB/p65(Ser276) in EMT process that may be considered a therapeutic strategy to inhibit lymph node metastasis in breast cancer patients.

Positive lymph-node breast cancer patients ­ activation of NF-κB in tumor-associated leukocytes stimulates cytokine secretion that promotes metastasis via C-C chemokine receptor CCR7.

Tumor metastasis to lymph nodes is most deadly complication among breast cancer patients. Herein, we investigated the molecular mechanism by which tumor-associated leukocytes (TALs) mediate lymph node metastasis. The density of different leukocyte subtypes infiltrating the tumor microenvironment of negative and positive lymph nodes (nLNs, pLNs) in breast cancer patients was measured using immunohistochemistry. In addition, we isolated TALs from blood drained from the axillary tributaries of nLN and pLN patients during breast surgery. Secretions of TALs were subjected to cytokine profiling using a cytokine antibody array. Our results showed an increase in the number of infiltrated CD45+ cells in the carcinoma tissues of pLN patients with the major proportion being myeloid subsets compared with nLN patients. Furthermore, TALs of pLN patients show a significant fivefold increase in the secretion of interleukin (IL)-1α, interferon-γ, IL-5, IL-3 and tumor necrosis factor-ß, and are characterized by enhanced constitutive NF-κB/p65 signaling compared with TALs isolated from nLN patients. Using an invasion assay, cytokines secreted by TALs of pLN patients were shown to augment the invasive phenotype of breast cancer MCF-7 and SKBR3 cells compared with nLN patients. Using flow cytometry, we found that C-C chemokine receptor 7 (CCR7) is significantly overexpressed in breast carcinoma of pLN patients compared with nLNs patients. Intriguingly, CCR7, a mechanistic clue for metastasis, is upregulated in MCF-7 cells upon stimulation with TAL-conditioned media of pLN patients. Our findings show that the molecular cues secreted by TALs alone or in combination with CCR7 may emerge as future therapeutic targets for lymph node metastasis in breast cancer patients.

MicroRNA regulation of proteoglycan function in cancer.

MicroRNAs are small noncoding RNAs acting as physiological regulators of gene expression at the post-transcriptional level. In cancer, the expression of microRNAs is dysregulated compared to healthy tissue, suggesting a mechanistic role in disease progression. Recent experimental evidence supports the important molecular role of proteoglycans as microRNA targets in this process. Misexpression of specific microRNAs results in aberrant expression patterns of proteoglycans, as well as their biosynthetic enzymes. Consequently, cell proliferation and apoptosis, adhesion, migration, invasiveness, epithelial-to-mesenchymal transition and cancer stem cell properties are affected as a result of the multifunctional properties of proteoglycans. A pharmacological targeting of the microRNA-proteoglycan axis emerges as a new therapeutic concept in cancer.

HS3ST2 modulates breast cancer cell invasiveness via MAP kinase- and Tcf4 (Tcf7l2)-dependent regulation of protease and cadherin expression.

Heparan sulfate 3-O-sulfotransferase 2 (HS3ST2), an enzyme mediating 3-O-sulfation of heparan sulfate (HS), is silenced by hypermethylation in breast cancer. As HS has an important co-receptor function for numerous signal transduction pathways, the phenotypical changes due to HS3ST2 reexpression were investigated in vitro using high and low invasive breast cancer cell lines. Compared to controls, highly invasive HS3ST2-expressing MDA-MB-231 cells showed enhanced Matrigel invasiveness, transendothelial migration and motility. Affymetrix screening and confirmatory real-time PCR and Western blotting analysis revealed increased expression of several matrix metalloproteinases, cadherin-11, E-cadherin and CEACAM-1, while protease inhibitor and annexin A10 expression were decreased. Low invasive HS3ST2 -expressing MCF-7 cells became even less invasive, with no change in gelatinolytic MMP activity. HS3ST2 expression increased HS-dependent basal and FGF2-specific signaling through the constitutively active p44/42 MAPK pathway in MDA-MB-231 cells. Increased MAPK activation was accompanied by upregulation of ß-catenin in MDA-MB-231, and of the transcription factor Tcf4 in both cell lines. Dysregulation of Tcf4-regulated ion transporters and increased cytosolic acidification were observed in HS3ST2-expressing MDA-MB-231 cells, which is a possible underlying cause of increased chemosensitivity towards doxorubicine and paclitaxel in these cells. This study provides the first in vitro evidence of the involvement of HS3ST2 in breast cancer cell invasion and chemosensitivity.

Syndecan-1 modulates ß-integrin-dependent and interleukin-6-dependent functions in breast cancer cell adhesion, migration, and resistance to irradiation.

Syndecan-1 is a cell surface heparan sulfate proteoglycan with various biological functions relevant to tumor progression and inflammation, including cell-cell adhesion, cell-matrix interaction, and cytokine signaling driving cell proliferation and motility. Syndecan-1 is a prognostic factor in breast cancer, and has a predicitive value for neodadjuvant chemotherapy. It is still poorly understood how syndecan-1 integrates matrix-dependent and cytokine-dependent signaling processes in the tumor microenvironment. Here, we evaluated the potential role of syndecan-1 in modulating matrix-dependent breast cancer cell migration in the presence of interleukin-6, and its potential involvement in resistance to irradiation in vitro. MDA-MB-231 breast cancer cells were transiently transfected with syndecan-1 small interfering RNA or control reagents, and this was followed by stimulation with interleukin-6 or irradiation. Cellular responses were monitored by adhesion, migration and colony formation assays, as well as analysis of cell signaling. Syndecan-1 depletion increased cell adhesion to fibronectin. Increased migration on fibronectin was significantly suppressed by interleukin-6, and GRGDSP peptides inhibited both adhesion and migration. Interleukin-6-induced activation of focal adhesion kinase and reduction of constitutive nuclear factor kappaB signaling were decreased in syndecan-1-deficient cells. Focal adhesion kinase hyperactivation in syndecan-1-depleted cells was associated with dramatically reduced radiation sensitivity. We conclude that loss of syndecan-1 leads to enhanced activation of ß1 -integrins and focal adhesion kinase, thus increasing breast cancer cell adhesion, migration, and resistance to irradiation. Syndecan-1 deficiency also attenuates the modulatory effect of the inflammatory microenvironment constituent interleukin-6 on cancer cell migration.

Syndecan-1 (CD138) modulates triple-negative breast cancer stem cell properties via regulation of LRP-6 and IL-6-mediated STAT3 signaling.

Syndecan-1 (CD138), a heparan sulfate proteoglycan, acts as a coreceptor for growth factors and chemokines and is a molecular marker associated with epithelial-mesenchymal transition during development and carcinogenesis. Resistance of Syndecan-1-deficient mice to experimentally-induced tumorigenesis has been linked to altered Wnt-responsive precursor cell pools, suggesting a potential role of Syndecan-1 in breast cancer cell stem function. However, the precise molecular mechanism is still elusive. Here, we decipher the functional impact of Syndecan-1 knockdown using RNA interference on the breast cancer stem cell phenotype of human triple-negative MDA-MB-231 and hormone receptor-positive MCF-7 cells in vitro employing an analytical flow cytometric approach. Successful Syndecan-1 siRNA knockdown was confirmed by flow cytometry. Side population measurement by Hoechst dye exclusion and Aldehyde dehydrogenase-1 activity revealed that Syndecan-1 knockdown in MDA-MB-231 cells significantly reduced putative cancer stem cell pools by 60% and 27%, respectively, compared to controls. In MCF-7 cells, Syndecan-1 depletion reduced the side population by 40% and Aldehyde dehydrogenase-1 by 50%, repectively. In MDA-MB-231 cells, the CD44(+)CD24(-/low) phenotype decreased significantly by 6% upon siRNA-mediated Syndecan-1 depletion. Intriguingly, IL-6, its receptor sIL-6R, and the chemokine CCL20, implicated in regulating stemness-associated pathways, were downregulated by >40% in Syndecan-1-silenced MDA-MB-231 cells, which showed a dysregulated response to IL-6-induced shifts in E-cadherin and vimentin expression. Furthermore, activation of STAT-3 and NFkB transcription factors and expression of a coreceptor for Wnt signaling, LRP-6, were reduced by >45% in Syndecan-1-depleted cells compared to controls. At the functional level, Syndecan-1 siRNA reduced the formation of spheres and cysts in MCF-7 cells grown in suspension culture. Our study demonstrates the viability of flow cytometric approaches in analyzing cancer stem cell function. As Syndecan-1 modulates the cancer stem cell phenotype via regulation of the Wnt and IL-6/STAT3 signaling pathways, it emerges as a promising novel target for therapeutic approaches.

Targeting of syndecan-1 by microRNA miR-10b promotes breast cancer cell motility and invasiveness via a Rho-GTPase- and E-cadherin-dependent mechanism.

microRNAs are small endogenous noncoding RNAs, which post-transcriptionally regulate gene expression. In breast cancer, overexpression of the transmembrane heparan sulfate proteoglycan syndecan-1, a predicted target of the oncomiR miR-10b, correlates with poor clinical outcome. To investigate the potential functional relationship of miR-10b and syndecan-1, MDA-MB-231 and MCF-7 breast cancer cells were transiently transfected with pre-miR-10b, syndecan-1 siRNA or control reagents, respectively. Altered cell behavior was monitored by proliferation, migration and invasion chamber assays, and time-lapse video microscopy. miR-10b overexpression induced post-transcriptional downregulation of syndecan-1, as demonstrated by quantitative real-time PCR (qPCR), flow cytometry, and 3'UTR luciferase assays, resulting in increased cancer cell migration and matrigel invasiveness. Syndecan-1 silencing generated a copy of this phenotype. Adhesion to fibronectin and laminin and basal cell proliferation was increased. Syndecan-1 coimmunoprecipitated with focal adhesion kinase, which showed increased activation upon syndecan-1 depletion. Affymetrix screening and confirmatory qPCR and Western blotting analysis of syndecan-1-deficient cells revealed upregulation of ATF-2, COX-2, cadherin-11, vinculin, actin γ 2, MYL9, transgelin-1, RhoA/C, matrix metalloproteinase 2 (MMP2) and heparanase, and downregulation of AML1/RUNX1, E-cadherin, CLDN1, p21WAF/CIP, cyclin-dependent kinase 6, TLR-4, PAI1/2, Collagen1alpha1, JHDM1D, Mpp4, MMP9, matrilin-2 and ANXA3/A10. Video microscopy demonstrated massively increased Rho kinase-dependent motility of syndecan-1-depleted cells, which displayed increased filopodia formation. We conclude that syndecan-1 is a novel target of the oncomiR miR-10b. Rho-GTPase-dependent modulation of cytoskeletal function and downregulation of E-cadherin expression are identified as relevant effectors of the miR-10b-syndecan-1 axis, which emerges as a promising target for the development of new therapeutic approaches for breast cancer.

T cells are depleted in HCV-Induced hepatocellular carcinoma patients: possible role of apoptosis and p53.

Egypt has possibly the highest Hepatitis C Virus (HCV) prevalence worldwide. A high proportion of HCV infections become chronic and lead to liver cirrhosis and hepatocellular carcinoma (HCC). The cellular and molecular mechanisms behind HCV infection complication are not completely understood although apoptosis has been implicated in this process. Using flowcytometry, we examined whether T lymphocyte; isolated from patients with HCV and HCV-associated HCC (HCV-HCC); are predestined in vivo to undergo spontaneous apoptosis. Also, the role of p53; a key protein in apoptotic process; in the development of HCC was examined. Our data showed that T cells were severely depleted in HCV-HCC patients and its spontaneous apoptosis was higher in patient groups as compared to normal controls. In addition, p53 expression in liver tissue (determined by ELISA) was higher in the HCC patient groups as compared to normal controls and correlated well with the HCC grade. In conclusion, HCV infection induces peripheral T cell apoptosis, depletion and subsequently immune-suppression and this may lead to persistence of infection. Also, p53 is implicated in the poor prognosis of HCV-HCC and could be used as a predictive marker to assess the prognosis of HCC patients.