Effect of Down-Regulated Transcriptional Repressor ZEB1 on the Epithelial-Mesenchymal Transition of Ovarian Cancer Cells:

Genome-wide DNA methylome and transcriptome changes induced by inorganic nanoparticles in human kidney cells after chronic exposure

The unique physicochemical properties make inorganic nanoparticles (INPs) an exciting tool in diagnosis and disease management. However, as INPs are relatively difficult to fully degrade and excrete, their unintended accumulation in the tissue might result in adverse health effects. Herein, we provide a methylome-transcriptome framework for chronic effects of INPs, commonly used in biomedical applications, in human kidney TH-1 cells. Renal clearance is one of the most important routes of nanoparticle excretion; therefore, a detailed evaluation of nanoparticle-mediated nephrotoxicity is an important task. Integrated analysis of methylome and transcriptome changes induced by INPs (PEG-AuNPs, Fe3O4NPs, SiO2NPs, and TiO2NPs) revealed significantly deregulated genes with functional classification in immune response, DNA damage, and cancer-related pathways. Although most deregulated genes were unique to individual INPs, a relatively high proportion of them encoded the transcription factors. Interestingly, FOS hypermethylation inversely correlating with gene expression was associated with all INPs exposures. Our study emphasizes the need for a more comprehensive investigation of INPs' biological safety, especially after chronic exposure.

Eliciting effective tumor immunity against ovarian cancer by cancer stem cell vaccination

Advanced ovarian cancer (OC) patients have limited benefit from current relevant cytotoxic and targeted therapies following debulking surgery. Therefore, new therapeutic strategies are in urgent need. Immunotherapy has shown great potential in tumor treatment, especially in tumor vaccine development. The study objective was to evaluate the immune effects of cancer stem cells (CSCs) vaccines on OC. The CD44⁺CD117⁺CSCs were isolated from human OC HO8910 and SKOV3 cells using the magnetic cell sorting system; the cancer stem-like cells were selected from murine OC ID8 cell by no-serum formed sphere culture. The CSC vaccines were prepared by freezing and thawing these CSCs, which were then injected into mice followed by challenging the different OC cells. The in vivo antitumor efficacy of CSC immunization revealed the vaccines were capable of significantly provoking immune responses to autologous tumor antigens in vaccinated mice as the mice were found to have markedly inhibited tumor growth, prolonged survival, and decreased CSC counts in OC tissues when compared to mice without the CSC vaccination. The in vitro cytotoxicities of immunocytes toward SKOV3, HO8910 and ID8 cells indicated a significant killing efficacy compared with the controls. However, the antitumor efficacy was remarkably reduced whilst the mucin-1 expression in CSC vaccines was down-regulated by small interfering RNA. Overall, findings from this study provided the evidence that has deepened our understanding of CSC vaccine immunogenicity and anti-OC efficacy, particularly for the role of dominant antigen mucin-1. It is possible to turn the CSC vaccine into an immunotherapeutic approach against ovarian cancer.

Salinomycin-Loaded High-Density Lipoprotein Exerts Promising Anti-Ovarian Cancer Effects by Inhibiting Epithelial-Mesenchymal Transition

Background

Effective treatments for ovarian cancer remain elusive, and survival rates have long been considered grim. Ovarian cancer stem cells (OCSCs) and epithelial–mesenchymal transition (EMT) are associated with cancer progression and metastasis, as well as drug resistance and eventual treatment failure. Salinomycin (Sal) has an extensive effect on a variety of cancer stem cells (CSCs); however, its poor water solubility and toxicity to healthy tissues at high doses limit further research into its potential as an anti-cancer drug. We proposed a therapeutic strategy by constructing a tumor-targeting carrier that mimics high-density lipoprotein (HDL) to synthesize salinomycin-loaded high-density lipoprotein (S-HDL). This strategy helps reduce the side effects of salinomycin, thereby improving its clinical benefits.

Methods

OCSCs were isolated from ovarian cancer cells (OCCs) and the uptake of HDL nanoparticles was observed using laser confocal microscopes. After the cell viability analysis revealed the inhibitory effect of S-HDL on OCCs and OCSCs, the main biological processes influenced by S-HDL were predicted with a transcriptome sequencing analysis and verified in vitro and in vivo.

Results

Cellular uptake analysis showed that the HDL delivery system was able to significantly enhance the uptake of Sal by OCCs, tentatively validating the targeting role of recombinant HDL, so that S-HDL could reduce the toxicity of Sal and increase its anti-ovarian cancer effects. Conversely, S-HDL could exert anti-ovarian cancer effects by inhibiting the proliferation of OCCs and OCSCs, promoting apoptosis, blocking EMT, and suppressing stemness and angiogenesis-related protein expression in vitro and in vivo.

Conclusion

S-HDL had stronger anti-ovarian cancer effects than unencapsulated Sal. Thus, it may be a potential agent for ovarian cancer treatment in the future.

The EMT-activator ZEB1 is unrelated to platinum drug resistance in ovarian cancer but is predictive of survival

The IGROVCDDP cisplatin-resistant ovarian cancer cell line is an unusual model, as it is also cross-resistant to paclitaxel. IGROVCDDP, therefore, models the resistance phenotype of serous ovarian cancer patients who have failed frontline platinum/taxane chemotherapy. IGROVCDDP has also undergone epithelial-mesenchymal transition (EMT). We aim to determine if alterations in EMT-related genes are related to or independent from the drug-resistance phenotypes. EMT gene and protein markers, invasion, motility and morphology were investigated in IGROVCDDP and its parent drug-sensitive cell line IGROV-1. ZEB1 was investigated by qPCR, Western blotting and siRNA knockdown. ZEB1 was also investigated in publicly available ovarian cancer gene-expression datasets. IGROVCDDP cells have decreased protein levels of epithelial marker E-cadherin (6.18-fold, p = 1.58e-04) and higher levels of mesenchymal markers vimentin (2.47-fold, p = 4.43e-03), N-cadherin (4.35-fold, p = 4.76e-03) and ZEB1 (3.43-fold, p = 0.04). IGROVCDDP have a spindle-like morphology consistent with EMT. Knockdown of ZEB1 in IGROVCDDP does not lead to cisplatin sensitivity but shows a reversal of EMT-gene signalling and an increase in cell circularity. High ZEB1 gene expression (HR = 1.31, n = 2051, p = 1.31e-05) is a marker of poor overall survival in high-grade serous ovarian-cancer patients. In contrast, ZEB1 is not predictive of overall survival in high-grade serous ovarian-cancer patients known to be treated with platinum chemotherapy. The increased expression of ZEB1 in IGROVCDDP appears to be independent of the drug-resistance phenotypes. ZEB1 has the potential to be used as biomarker of overall prognosis in ovarian-cancer patients but not of platinum/taxane chemoresistance.

Elevated IL-35 level and iTr35 subset increase the bacterial burden and lung lesions in Mycobacterium tuberculosis-infected mice

This study aimed to investigate the relationship between interleukin (IL)-35 level and IL-35-producing regulatory T cells (iTr35 subset) in Mycobacterium tuberculosis (Mtb)-infected mice. After the mice were injected with Mtb strain H37R via tail vein, the bacterial burden, lung lesions, and the impact of immune suppression on the infected mice were respectively assessed. The results, when compared with the control mice, showed that the mRNA expression levels of the p35 and Epstein-Barr virus-induced gene 3 of IL-35 were significantly increased in the Mtb-infected mouse spleen at 4 or 8 weeks post-infection and their protein expression levels were concurrently increased in the lungs of the mice, especially in 8 week infected mice. In addition, the levels of serum IL-35 and the iTr35 subset in the spleen of mice were also increased in 4 or 8 weeks post-infection compared with the control mice. Importantly, the high bacterial burden and lung lesions and the low mouse weight were found at 8 week post-infection. Therefore, the mice infected with Mtb resulted in elevating IL-35 level and iTr35 subset and increasing bacterial burden and lung lesions. The findings from the study suggest IL-35 and iTr35 cells may exert an immune suppression role in chronic Mtb-infected mice.

Aberrant Methylation of 20 miRNA Genes Specifically Involved in Various Steps of Ovarian Carcinoma Spread: From Primary Tumors to Peritoneal Macroscopic Metastases

Our work aimed to differentiate 20 aberrantly methylated miRNA genes that participate at different stages of development and metastasis of ovarian carcinoma (OvCa) using methylation-specific qPCR in a representative set of clinical samples: 102 primary tumors without and with metastases (to lymph nodes, peritoneum, or distant organs) and 30 peritoneal macroscopic metastases (PMM). Thirteen miRNA genes (MIR107, MIR124-2, MIR124-3, MIR125B-1, MIR127, MIR129-2, MIR130B, MIR132, MIR193A, MIR339, MIR34B/C, MIR9-1, and MIR9-3) were hypermethylated already at the early stages of OvCa, while hypermethylation of MIR1258, MIR137, MIR203A, and MIR375 was pronounced in metastatic tumors, and MIR148A showed high methylation levels specifically in PMM. We confirmed the significant relationship between methylation and expression levels for 11 out of 12 miRNAs analyzed by qRT-PCR. Moreover, expression levels of six miRNAs were significantly decreased in metastatic tumors in comparison with nonmetastatic ones, and downregulation of miR-203a-3p was the most significant. We revealed an inverse relationship between expression levels of miR-203a-3p and those of ZEB1 and ZEB2 genes, which are EMT drivers. We also identified three miRNA genes (MIR148A, MIR9-1, and MIR193A) that likely regulate EMT–MET reversion in the colonization of PMM. According to the Kaplan–Meier analysis, hypermethylation of several examined miRNA genes was associated with poorer overall survival of OvCa patients, and high methylation levels of MIR130B and MIR9-1 were related to the greatest relative risk of death.

Chondroitin sulfate proteoglycan 4, a targetable oncoantigen that promotes ovarian cancer growth, invasion, cisplatin resistance and spheroid formation

Epithelial ovarian cancer (EOC) is a highly heterogeneous disease encompassing several distinct molecular subtypes and clinical entities. Despite the initial success of surgical debulking and adjuvant chemotherapy, recurrence with chemotherapy resistant tumors is common in patients with EOC and leads to poor overall survival. The extensive genetic and phenotypic heterogeneity associated with ovarian cancers has hindered the identification of effective prognostic and predictive biomarkers in EOC patients. In the current studies, we identify a tumor cell surface oncoantigen, chondroitin sulfate proteoglycan 4 (CSPG4), as an independent risk factor for decreased survival of patients with EOC. Our results show that CSPG4 promotes EOC cell invasion, cisplatin resistance and spheroid formation in vitro and tumor expansion in vivo. Mechanistically, spheroid formation and tumor cell invasion are due to CSPG4-stimulated expression of the mesenchymal transcription factor ZEB1. Furthermore, we have developed a novel monoclonal anti-CSGP4 antibody against the juxtamembrane domain of the core protein that limits CSPG4-stimulated ZEB1 expression, tumor cell invasion and promotes EOC apoptosis within spheroid cultures. We therefore propose that CSPG4 expression drives phenotypic heterogeneity and malignant progression in EOC tumors. These studies further demonstrate that CSPG4 expression levels are a potential diagnostic biomarker in EOC and indicate that targeting cells which express this oncoantigen could limit recurrence and improve outcomes in patients with EOC.

Liposomal paclitaxel induces apoptosis, cell death, inhibition of migration capacity and antitumoral activity in ovarian cancer

The main goal of this study is to evaluate the efficacy of the paclitaxel (PTX) drug formulated with a liposomal nanosystem (L-PTX) in a peritoneal carcinomatosis derived from ovarian cancer. In vitro cell viability studies with the human ovarian cancer line A2780 showed a 50% decrease in the inhibitory concentration for L-PTX compared to free PTX. A2780 cells treated with the L-PTX formulation demonstrated a reduced capacity to form colonies in comparison to those treated with PTX. Cell death following L-PTX administration hinted at apoptosis, with most cells undergoing initial apoptosis. A2780 cells exhibited an inhibitory migration profile when analyzed by Wound Healing and real-time cell analysis (xCELLigence) methods after L-PTX administration. This inhibition was related to decreased expression of the zinc finger E-box-binding homeobox 1 (ZEB1) and transforming growth factor 2 (TGF-β2) genes. In vivoL-PTX administration strongly inhibited tumor cell proliferation in ovarian peritoneal carcinomatosis derived from ovarian cancer, indicating higher antitumor activity than PTX. L-PTX formulation did not show toxicity in the mice model. This study demonstrated that liposomal paclitaxel formulations are less toxic to normal tissues than free paclitaxel and are more effective in inhibiting tumor cell proliferation/migration and inducing ZEB1/TGF-β2 gene expression.

Targeting endothelin 1 receptor-miR-200b/c-ZEB1 circuitry blunts metastatic progression in ovarian cancer

Identification of regulatory mechanisms underlying the poor prognosis of ovarian cancer is necessary for diagnostic and therapeutic implications. Here we show that endothelin A receptor (ET_AR) and ZEB1 expression is upregulated in mesenchymal ovarian cancer and correlates with poor prognosis. Notably, the expression of ET_AR and ZEB1 negatively correlates with miR-200b/c. These miRNAs, besides targeting ZEB1, impair ET_AR expression through the 3’UTR binding. ZEB1, in turn, restores ET_AR levels by transcriptionally repressing miR-200b/c. Activation of ET_AR drives the expression of ZEB1 integrating the miR-200/ZEB1 double negative feedback loop. The ET_AR-miR-200b/c-ZEB1 circuit promotes epithelial-mesenchymal transition, cell plasticity, invasiveness and metastasis. Of therapeutic interest, ET_AR blockade with macitentan, a dual ET_AR and ET_BR antagonist, increases miR-200b/c and reduces ZEB1 expression with the concomitant inhibition of metastatic dissemination. Collectively, these findings highlight the reciprocal network that integrates ET_AR and ZEB1 axes with the miR-200b/c regulatory circuit to favour metastatic progression in ovarian cancer.

Rosanna Sestito et al. report a miR-200b/c-mediated regulatory circuit that drives ovarian cancer metastasis via the endothelin A receptor (ET_AR). They show that blockade of ET_AR increases miR-200b/c expression and subsequently reduces ZEB1 expression, thereby inhibiting further metastatic progression.

MiR-7 reduces the BCSC subset by inhibiting XIST to modulate the miR-92b/Slug/ESA axis and inhibit tumor growth

BACKGROUND

Breast cancer stem cells (BCSCs) are typically seed cells of breast tumor that initiate and maintain tumor growth. MiR-7, as a cancer inhibitor, decreases the BCSC subset and inhibits tumor progression through mechanisms that remain unknown.

METHODS

We examined miR-7 expression in breast cancer and developed a BCSC-driven xenograft mouse model, to evaluate the effects of miR-7 overexpression on the decrease of the BCSC subset in vitro and in vivo. In addition, we determined how miR-7 decreased the BCSC subset by using the ALDEFLUOR, lentivirus infection, dual-luciferase reporter, and chromatin immunoprecipitation-PCR assays.

RESULTS

MiR-7 was expressed at low levels in breast cancer tissues compared with normal tissues, and overexpression of miR-7 directly inhibited lncRNA XIST, which mediates the transcriptional silencing of genes on the X chromosome, and reduced epithelium-specific antigen (ESA) expression by increasing miR-92b and inhibiting slug. Moreover, miR-7 suppressed CD44 and ESA by directly inhibiting the NF-κB subunit RELA and slug in breast cancer cell lines and in BCSC-driven xenografts, which confirmed the antitumor activity in mice injected with miR-7 agomir or stably infected with lenti-miR-7.

CONCLUSIONS

The findings from this study uncover the molecular mechanisms by which miR-7 inhibits XIST, modulates the miR-92b/Slug/ESA axis, and decreases the RELA and CD44 expression, resulting in a reduced BCSC subset and breast cancer growth inhibition. These findings suggest a potentially targeted treatment approach to breast cancer.

Decreasing Microtubule Actin Cross-Linking Factor 1 Inhibits Melanoma Metastasis by Decreasing Epithelial to Mesenchymal Transition

Background

The microtubule actin cross-linking factor 1 (MACF1) is involved in cellular migration, adhesion, and invasion processes. Its abnormal expression initiates tumor cell proliferation and metastasis in numerous cancer types.

Methods

In this study, we utilized short hair-pin RNA interference of MACF1 to assess the inhibitory effects on the metastatic potential of B16F10 melanoma cells both in vitro and in vivo a mouse model.

Results

The MACF1 expression was increased in B16F10 cells-induced tumor tissues; while the down-regulation of MACF1 impacted the B16F10 melanoma cell metastatic behavior by decreasing the ability of colony formation and invasion in vitro as well as inhibiting B16F10 cells-induced tumor growth and lung metastasis in vivo. The results of Western blot and immunohistochemistry indicated that the expression of E-cadherin and Smad-7 was significantly increased whereas the expression of N-cadherin and TGF-β1 was significantly decreased in tumor tissue of mice challenged with the B16F10/MACF1-RNAi cells when compared with the B16F10 cells challenged mice.

Conclusion

The data presented in this study demonstrated that down-regulated MACF1 expression decreased B16F10 melanoma metastasis in mice by inhibiting the epithelial to mesenchymal transition program. Thus, MACF1 may be a novel target for melanoma therapy.

Ursolic acid suppresses the invasive potential of colorectal cancer cells by regulating the TGF-β1/ZEB1/miR-200c signaling pathway

Ursolic acid (UA) is a biologically active compound, commonly used in traditional Chinese medicine (TCM). It has been reported to exhibit strong anticancer properties against a variety of cancers. Our previous studies showed that UA promoted apoptosis in colorectal cancer (CRC) cells and inhibited cellular proliferation and angiogenesis. However, the effect and underlying molecular mechanism of UA in CRC progression remain unclear. In the present study, the role of UA in suppressing the migration and invasion of human colon cancer HCT116 and HCT-8 cells was investigated, using Transwell assays. In addition, to evaluate whether the anticancer properties of UA were mediated by the regulation of a double-negative feedback loop consisting of the transforming growth factor-β1 (TGF-β1)/zinc finger E-box-binding homeobox (ZEB1) pathway and microRNA (miR)-200a/b/c, reverse transcription-quantitative PCR and western blot analysis were performed. The results indicated that UA treatment significantly suppressed cellular growth, migration and invasion in HCT116 and HCT-8 cells in a dose-dependent manner. Furthermore, following UA treatment, several crucial mediators of the TGF-β1 signaling pathway, including TGF-β1, phosphorylated (p)-Smad2/3, p-focal adhesion kinase and ZEB1, were significantly downregulated in the HCT116 and HCT-8 cell lines compared with the control group. Furthermore, the ratio of N-cadherin/E-cadherin, two proteins directly downstream of the TGF-β1 signaling pathway, was found to be downregulated in UA treated CRC cells. Finally, UA significantly upregulated miR200a/b/c, with miR-200c exhibiting the highest increase in expression levels following UA treatment. Collectively, the present study suggested that inhibition of CRC cell invasion by UA occurred via regulation of the TGF-β1/ZEB1/miR-200c signaling network, which may be one of the mechanisms by which UA appears to be an effective therapeutic agent against colon cancer.

Ovarian Cancer Stem Cells with High ROR1 Expression Serve as a New Prophylactic Vaccine for Ovarian Cancer

Tumor vaccines offer a number of advantages for cancer treatment. In the study, the vaccination with cancer stem cells (CSCs) with high expression of the type I receptor tyrosine kinase-like orphan receptor (ROR1) was evaluated in a murine model for the vaccine's immunogenicity and protective efficacy against epithelial ovarian carcinoma (EOC). CD117⁺CD44⁺ CSCs were isolated from human EOC HO8910 cell line using a magnetic-activated cell sorting system; murine ID8 EOC suspension sphere cells, which are collectively known as cancer stem-like cells, were acquired from serum-free suspension sphere-forming culture. Mice were subcutaneously immunized with the repeat cycles of freezing and thawing whole HO8910 CD117⁺CD44⁺ CSCs and ID8 cancer stem-like cells, respectively, followed by a challenge with HO8910 or ID8 cells at one week after final vaccination. The results showed that the CSC vaccination significantly induced immunity against EOC growth and markedly prolonged the survival of EOC-bearing mice in the prophylactic setting compared with non-CSC vaccination. Flow cytometry showed significantly increased immunocyte cytotoxicities and remarkably reduced CSC counts in the CSC-vaccinated mice. Moreover, the protective efficacy against EOC was decreased when the ROR1 expression was downregulated by shRNA in CSC vaccines. The findings from the study suggest that CSC vaccines with high ROR1 expression were highly effective in triggering immunity against EOC in vaccinated mice and may serve as an effective vaccine for EOC immunoprophylaxis.

Jiedu Sangen Decoction Inhibits Migration and Invasion of Colon Cancer SW480 Cells via Suppressing Epithelial Mesenchymal Transition

Jiedu Sangen Decoction (JSD), a traditional Chinese medicine (TCM) formula, has been widely used in China to treat gastrointestinal cancer, especially as an adjuvant therapy in colorectal cancer (CRC) patients. This study aimed to evaluate the efficacy of JSD and Jiedu Sangen aqueous extract (JSAE) in colon cancer cells and explored the underlining mechanisms by cytotoxicity assay, scratch assay, transwell migration assay, matrigel invasion assay, confocal laser scanning microscopy, and western blot analysis. We demonstrated that JSAE inhibited the growth of colon cancer SW480 cells in a dose-dependent manner and JSAE repressed cancer cell migration and invasion. Furthermore, epithelial mesenchymal transition (EMT) was reversed by JSAE via enhancing E-cadherin expression and attenuating protein levels of EMT promoting factors such as N-cadherin, Slug, and ZEB1. These findings provided the first experimental evidence confirming the efficacy of JSAE in repressing invasion and metastasis of CRC and paving a way for the broader use of JSD in clinic.

Targeting epithelial-mesenchymal transition and cancer stem cells for chemoresistant ovarian cancer

Chemoresistance is the main challenge for the recurrent ovarian cancer therapy and responsible for treatment failure and unfavorable clinical outcome. Understanding mechanisms of chemoresistance in ovarian cancer would help to predict disease progression, develop new therapies and personalize systemic therapy. In the last decade, accumulating evidence demonstrates that epithelial-mesenchymal transition and cancer stem cells play important roles in ovarian cancer chemoresistance and metastasis. Treatment of epithelial-mesenchymal transition and cancer stem cells holds promise for improving current ovarian cancer therapies and prolonging the survival of recurrent ovarian cancer patients in the future. In this review, we focus on the role of epithelial-mesenchymal transition and cancer stem cells in ovarian cancer chemoresistance and explore the therapeutic implications for developing epithelial-mesenchymal transition and cancer stem cells associated therapies for future ovarian cancer treatment.

TWIST1 induces expression of discoidin domain receptor 2 to promote ovarian cancer metastasis

The mesenchymal gene program has been shown to promote the metastatic progression of ovarian cancer; however, specific proteins induced by this program that lead to these metastatic behaviors have not been identified. Using patient derived tumor cells and established human ovarian tumor cell lines, we find that the Epithelial-to –Mesenchymal Transition inducing factor TWIST1 drives expression of Discoidin Domain Receptor 2 (DDR2), a receptor tyrosine kinase (RTK) that recognizes fibrillar collagen as ligand. The expression and action of DDR2 was critical for mesothelial cell clearance, invasion and migration in ovarian tumor cells. It does so, in part, by upregulating expression and activity of matrix remodeling enzymes that lead to increased cleavage of fibronectin and spreading of tumor cells. Additionally, DDR2 stabilizes SNAIL1, allowing for sustained mesenchymal phenotype. In patient derived ovarian cancer specimens, DDR2 expression correlated with enhanced invasiveness. DDR2 expression was associated with advanced stage ovarian tumors and metastases. In vivo studies demonstrated that the presence of DDR2 is critical for ovarian cancer metastasis. These findings indicate that the collagen receptor DDR2 is critical for multiple steps of ovarian cancer progression to metastasis, and thus, identifies DDR2 as a potential new target for the treatment of metastatic ovarian cancer.

Effective tumor immunity to melanoma mediated by B16F10 cancer stem cell vaccine

Although tumor vaccines have been considered a promising immunotherapy approach, therapeutic tumor vaccines are mostly disappointing in the clinic due to vaccine weak immunogenicity. Cancer stem cells (CSCs) may broaden the antigenic breadth and effectively induce the immune responses against autologous cancer cells. Here we report on the development of the B16F10 CD133⁺CD44⁺CSCs (B16F10 CSCs) vaccine to induce tumor immunity to melanoma in mice. Efficacy of against melanoma was evaluated by analysis of tumor growth and mouse survival. Immunogenicity was assessed by ELISA and flow cytometric assays, including serum cytokines, cytotoxic activity of NK cells and splenocytes in the immunized mice. The results showed that the B16F10 CSC vaccine resulted in tumor shrinkage and mouse lifespan extension. The cytotoxic activity and IFN-γ level were significantly increased in mice immunized with B16F10 CSC vaccine compared with the mice immunized with control vaccines. Additionally, New York esophageal squamous cell carcinoma-1, an efficient tumor associated antigen over-expressed by B16F10 CSCs, was markedly reduced in expression in melanoma tissue, suggesting decrease of CSC subpopulation due to B16F10 CSC vaccination. Collectively, the findings may represent a new powerful approach for treatment of melanoma by B16F10 CSC vaccination.

Identification of cis-regulatory mutations generating de novo edges in personalized cancer gene regulatory networks

The identification of functional non-coding mutations is a key challenge in the field of genomics. Here we introduce μ-cisTarget to filter, annotate and prioritize cis-regulatory mutations based on their putative effect on the underlying "personal" gene regulatory network. We validated μ-cisTarget by re-analyzing the TAL1 and LMO1 enhancer mutations in T-ALL, and the TERT promoter mutation in melanoma. Next, we re-sequenced the full genomes of ten cancer cell lines and used matched transcriptome data and motif discovery to identify master regulators with de novo binding sites that result in the up-regulation of nearby oncogenic drivers. μ-cisTarget is available from http://mucistarget.aertslab.org .

Impact of positive ZEB1 expression in patients with epithelial ovarian carcinoma as an oncologic outcome-predicting indicator

Several previous studies have revealed that the expression of zinc finger E-box binding homeobox 1 (ZEB1) in solid malignancies has an important significance on the clinical outcome of patients. However, the association between ZEB1 expression and survival in patients with epithelial ovarian carcinoma (EOC) remains unclear. The objective of the present study was to examine the extent of ZEB1 expression in EOC using immunohistochemical staining and investigate its association with patient outcome. A total of 40 patients with EOC initially treated with cytoreductive surgery and systematic chemotherapy were enrolled. ZEB1 expression was immunohistochemically categorized as negative, weak, moderate and strong according to the size of the staining area, and intensity. Subsequently, the associations between ZEB1 expression and recurrence/progression-free survival (RFS) rate were examined. The median age of patients in the current study was 54 years old (range, 22-72 years old). Among these patients, 15 (37.5%) exhibited International Federation of Gynecology and Obstetrics stage I disease, and 10 (25.0%), 13 (32.5%), and 2 (5%) had stage II, III, and IV disease, respectively. No patients with negative expression of ZEB1 experienced recurrence. In addition, ZEB1 expression was identified to be a significant predictor of a poorer RFS rate compared with negative expression (negative vs. weak, moderate and strong, P=0.0126). Furthermore, multivariate analyses revealed that moderate and strong ZEB1 expression levels were significant prognostic indicators of a poorer RFS rate in patients with EOC (hazard ratio, 2.265; 95% confidence interval, 1.072-8.021; P=0.0349). Confining analysis to patients with the clear-cell/mucinous histological type, those with moderate/strong ZEB1 expression demonstrated a significantly poorer RFS rate (P=0.0025). Positive ZEB1 expression may be an indicator to predict unfavorable RFS in patients with EOC.

Differential role of microRNAs in prognosis, diagnosis, and therapy of ovarian cancer

Ovarian cancer (OC) is the most lethal of malignant gynecological cancers, and has a very poor prognosis, frequently, attributable to late diagnosis and responsiveness to chemotherapy. In spite of the technological and medical approaches over the past four decades, involving the progression of several biological markers (mRNA and proteins biomarkers), the mortality rate of OC remains a challenge due to its late diagnosis, which is expressly ascribed to low specificities and sensitivities. Consequently, there is a crucial need for novel diagnostic and prognostic markers that can advance and initiate more individualized treatment, finally increasing survival of the patients. MiRNAs are non-coding RNAs that control target genes post transcriptionally. They are included in tumorigenesis, apoptosis, proliferation, invasion, metastasis, and chemoresistance. Several studies have within the last decade demonstrated that miRNAs are dysregulated in OC and have possibilities as diagnostic and prognostic biomarkers for OC. Additionally; recent studies have also focused on miRNAs as predictors of chemotherapy sensitivities and their potential as therapeutic targets. In this review, we discuss the current data involving the accumulating evidence of the altered expression of miRNAs in OC, their role in diagnosis, prognosis, and forecast of response to therapy. Given the heterogeneity of this disease, it is likely that advances in long-term survival might be also attained by translating the recent insights of miRNAs participation in OC into new targeted therapies that will have a crucial effect on the management of ovarian cancer.

Combining TGF-β1 knockdown and miR200c administration to optimize antitumor efficacy of B16F10/GPI-IL-21 vaccine

TGF-β1 secreted abundantly by tumors cells as well as present in the local microenvironment promotes neoplasm invasion and metastasis by triggering the epithelial to mesenchymal transition (EMT). MiR200c has been shown to suppress EMT and to regulate the cellular epithelial and interstitial state conversion, whereas the tumor vaccines are intended to specifically initiate or amplify a host response against evolving tumor cells. Our study aimed at optimizing the antitumor effects of the B16F10/glycosylphosphatidylinositol-interleukin 21 (B16F10/GPI-IL-21) tumor vaccine on melanoma bearing mice by combining the TGF-β1 knockdown and the administration of miR200c agomir. The mice were subcutaneously vaccinated with inactivated B16F10/GPI-IL-21 vaccine and challenged by B16F10 cells transfected with shTGF-β1 (B16F10/shTGF-β1 cells) or B16F10/shTGF-β1 cells with the administration of miR200c agomir. The later combination showed that, when compared with the mice in the control group that received no vaccination, vaccinated mice significantly increased NK and CTL activities, enhanced levels of IFN-γ, and reduced expression of TGF-β1, N-cadherin, Vimentin, Gli1/2, P-Smad2/3 and others involved in promoting expression of EMT-related molecules in tumor areas, and inhibited the melanoma metastasis in lungs and lymph nodes. Altogether, our findings demonstrate that this synergistic anti-cancer regimen effectively induces strong immune response and diminishes the melanoma progression.

Reinforcing B16F10/GPI-IL-21 vaccine efficacy against melanoma by injecting mice with shZEB1 plasmid or miR200c agomir

In this study, we hypothesized that the inhibition of epithelial to mesenchymal transition (EMT) program by knockdown of Zinc-finger E-box binding homeobox 1 (ZEB1) or administration of miR200c agomir would strengthen the B16F10 cells transfected with GPI-anchored IL-21 (B16F10/GPI-IL-21) vaccine efficacy in inhibiting the melanoma metastasis. Our findings from the current study indicated that, when compared with the mice immunized with the B16F10/GPI-IL-21 vaccine alone, the mice immunized with B16F10/GPI-IL-21 vaccine combined with injection of shZEB1 plasmid or miR200c agomir not only meaningfully inhibited EMT of melanoma, reduced the EMT characteristic molecular expression in tumor tissues, but also significantly decreased the Treg cells and TGF-β1, enhanced the cytotoxicities of NK cells and cytotoxic T lymphocytes and the IFN-γ level. Furthermore, the immunotherapeutic combination resulted in inhibiting the melanoma growth and lung metastasis. Our study demonstrated that using the B16F10/GPI-IL-21 vaccine in combination with the down-regulated ZEB1 or miR200c administration effectively elicited anti-tumor immunity and reduced melanoma metastasis by inhibiting the EMT program in the B16F10 melanoma-bearing mice.

Current status on microRNAs as biomarkers for ovarian cancer

Ovarian cancer (OC) is the most lethal gynecological malignancy in the Western world, and has a very poor prognosis, often due to late diagnosis and emergence of chemotherapy resistance. Therefore, there is an essential need for new diagnostic and prognostic markers that can improve and initiate more personalized treatment, eventually improving survival of the patients. MicroRNAs are small, non-coding RNA molecules, that post-transcriptionally regulate gene expression. Several studies have within the last decade shown that microRNAs are deregulated in OC and have potential as diagnostic and prognostic biomarkers for OC. Recently studies have also focused on microRNAs as predictors of chemotherapy responses and their potential as therapeutic targets. However, many of the published studies are difficult to interpret as a whole due to various methods of analysis. Future focus should be aimed at developing a general standardized analytical method, which can limit differences between studies thus allowing easier comparison across them. In addition, validation of studies in independent series that ideally should be histotype-specific is essential to determine the clinical role of microRNAs in different types of OC. In this review we summarize the current knowledge of microRNAs as potential biomarkers for OC, with focus on their clinical relevance.

Emodin inhibits epithelial to mesenchymal transition in epithelial ovarian cancer cells by regulation of GSK-3β/β-catenin/ZEB1 signaling pathway

Emodin (EMO) has been shown to possess pleiotropic anticancer capabilities in many types of cancer, including epithelial ovarian cancer (EOC). Inhibitory efficacy of EMO on EOC invasion and migration was previously observed, however, the underlying mechanisms have not been completely elucidated. The present study is aimed to explore the mechanisms. Transwell assay demonstrated that EMO significantly inhibited A2780 and SK-OV-3 cell invasion. Western blot analysis was performed to detect the expression levels of epithelial to mesenchymal transition (EMT)-related markers. We found that EMO treatment dose-dependently upregulated E-cadherin, keratin and downregulated N-cadherin, vimentin, matrix metalloproteinase-9 (MMP-9) and matrix metalloproteinase-2 (MMP-2) to repress EMT. Mechanistically, EMO could inhibit glycogen synthase kinase 3β (GSK-3β) phosphorylation, decrease total β-catenin protein levels and subsequently downregulate transcription factor zinc finger E-box binding homeobox 1 (ZEB1) expression. These effects of EMO were weakened when the cells were pretreated with SB216763, an inhibitor of GSK-3β kinase. Besides, we utilized small interfering RNA (siRNA) to downregulate ZEB1 expression. We found that treatment of ZEB1-knockdown cells with EMO, ZEB1 levels were lowest and cell invasion was weakest but ZEB1 knockdown had no effect on the expression of phospho-Ser9-GSK-3β (p-GSK-3βSer9), β-catenin. In conclusion, our results suggested that EMO inhibited EOC cell invasion by regulation of GSK-3β/β-catenin/ZEB1 signaling pathway to suppress EMT in vitro.

Effect of targeted ovarian cancer immunotherapy using ovarian cancer stem cell vaccine

Background

Accumulating evidence has shown that different immunotherapies for ovarian cancer might overcome barriers to resistance to standard chemotherapy. The vaccine immunotherapy may be a useful one addition to conditional chemotherapy regimens. The present study investigated the use of vaccine of ovarian cancer stem cells (CSCs) to inhibit ovarian cancer growth.

Methods

CD117⁺CD44⁺CSCs were isolated from human epithelial ovarian cancer (EOC) SKOV3 cell line by using a magnetic-activated cell sorting system. Pre-inactivated CD117⁺CD44⁺CSC vaccine was vacccinated into athymic nude mice three times, and then the mice were challenged subcutaneously with SKOV3 cells. The anti-tumor efficacy of CSC vaccine was envaluated by in vivo tumorigenicity, immune efficient analysis by flow cytometer, and enzyme-linked immunosorbent assays, respectively.

Results

The CD117⁺ CD44⁺CSC vaccine increased anti-ovarian cancer efficacy in that it depressed ovarian cancer growth in the athymic nude mice. Vaccination resulted in enhanced serum IFN-γ, decreased TGF-β levels, and increased cytotoxic activity of natural killer cells in the CD117⁺ CD44⁺CSC vaccine immunized mice. Moreover, the CSC-based vaccine significantly reduced the CD117⁺CD44⁺CSC as well as the aldehyde dehydrogenase 1 positive cell populations in the ovarian cancer tissues in the xenograft mice.

Conclusion

The present study provided the first evidence that human SKOV3 CD117⁺ CD44⁺CSC-based vaccine may induce the anti-ovarian cancer immunity against tumor growth by reducing the CD117⁺CD44⁺CSC population.

Inhibitory effect of epirubicin-loaded lipid microbubbles with conjugated anti-ABCG2 antibody combined with therapeutic ultrasound on multiple myeloma cancer stem cells

Ultrasound-targeted microbubble destruction (UTMD) technique is thought to improve the chemotherapeutic agent delivery from microbubbles (MBs) in tumor tissues and reduce the side effects in non-tumor tissues. Multiple myeloma (MM) is a bone marrow cancer and remains to be an incurable disease. In this study, we used the UTMD technique to investigate the inhibitory effect of our developed novel reagent on MM cancer stem cells (CD138(-)CD34(-)MM CSCs) that are MM cells with CD138(-)CD34(-) phenotypes, responsible for MM-initiating potential, drug resistance and eventual relapse. The preparatory steps of novel reagent was first epirubicin (EPI)-loaded in the lipid MBs that was consisted of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000]-biotin, dipalmitoyl-phosphatidylglycerol and 25-NBD-cholesterol, then anti-ABCG2 monoclonal antibody (mAb) was conjugated onto the MB surface to form EPI-MBs+mAb. CD138(-)CD34(-)MM CSCs were isolated from human MM RPMI 8226 cell line by the magnetic associated cell sorting method. The results showed that the attenuated proliferation, migration and invasion ability, and increased apoptosis were observed when MM CSCs were incubated with a various agents. EPI-MBs+mAb combined with therapeutic ultrasound significantly promoted the MM CSC apoptosis compared with EPI, EPI-MBs alone or EPI-MBs+mAb without ultrasound exposure. These results suggest that the developed EPI-MBs+mAb combined with therapeutic ultrasound remarkably induced MM CSC apoptosis in vitro.

ZEB1 promotes epithelial-mesenchymal transition in cervical cancer metastasis

OBJECTIVE

To investigate role of Zinc finger E-box binding homeobox 1 (ZEB1) in cervical cancer tissue (squamous cell carcinoma, SCC).

DESIGN

Exploratory study.

SETTING

University hospital.

PATIENT(S)

Sixty patients with SCC, including stage CINIII (n = 10), IB1 (n = 10), IB2 (n = 10), IIA1 (n = 10), IIA2 (n = 10), and IIB (n = 10) were studied.

INTERVENTION(S)

Caski cells were transfected with recombinant shZEB1 lentivirus or shCtrl lentivirus to generate stable ZEB1-knockdown Caski cells.

MAIN OUTCOME MEASURE(S)

ZEB1 expression was analyzed by quantitative real-time polymerase chain reaction and immunohistochemistry in cervical cancer tissues. ZEB1 expression in Caski cells was down-regulated by short-hairpin RNA (shRNA) interference, and changes in ZEB1 expression corresponded with changes in the proliferation and migratory ability of Caski cells.

RESULT(S)

Quantitative real-time polymerase chain reaction and immunohistochemistry results revealed that ZEB1 expression and the ratio of Vimentin to E-cadherin were high in 27 of 50 SCC patients and correlated with advanced International Federation of Gynecology and Obstetrics stage, tumor size >4 cm, and parametrial invasion. However, the expression of ZEB1 in cervical cancer tissue was independent of age and SCC antigen level. Transfection of ZEB1 shRNA in Caski cells significantly decreased the messenger RNA and protein expression of ZEB1, parallel with increased expression of the epithelial marker E-cadherin and decreased expression of the mesenchymal marker Vimentin. Furthermore, the proliferation and migratory ability of Caski cells were significantly lower in the transfected group than in the nontransfected control group.

CONCLUSION(S)

Down-regulation of ZEB1 expression may protect the invasive front of the tumors from converting to a mesenchymal phenotype by reducing the proliferation and motility of cervical cancer cells, suggesting that ZEB1 might be a potential therapeutic target for SCC.

Silencing of MICAL-L2 suppresses malignancy of ovarian cancer by inducing mesenchymal-epithelial transition

Ovarian cancer remains the disease with the highest associated mortality rate of gynecologic malignancy due to cancer metastasis. Rearrangement of actin cytoskeleton by cytoskeleton protein plays a critical role in tumor cell metastasis. MICAL-L2, a member of MICAL family, can interact with actin-binding proteins, regulate actin cross-linking and coordinate the assembly of adherens junctions and tight junctions. However, the roles of MICAL-L2 in tumors and diseases have not been explored. In this study, we found that MICAL-L2 protein is significantly up-regulated in ovarian cancer tissues along with FIGO stage and associated with histologic subgroups of ovarian cancer. Silencing of MICAL-L2 suppressed ovarian cancer cell proliferation, migration and invasion ability. Moreover, silencing of MICAL-L2 prevented nuclear translocation of β-catenin, inhibited canonical wnt/β-catenin signaling and induced the mesenchymal-epithelial transition (MET). Taken together, our data indicated that MICAL-L2 may be an important regulator of epithelial-mesenchymal transition (EMT) in ovarian cancer cells and a new therapeutic target for interventions against ovarian cancer invasion and metastasis.

ZEB1 as an indicator of tumor recurrence for areca quid chewing-associated oral squamous cell carcinomas

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the sixth most prevalent malignancy worldwide and the third most common cancer in developing nation. Most OSCC patients relapse within months after receiving treatment. Therefore, searching the biomarkers of recurrence is urgently required to improve OSCC patient survival.

METHODS

We set out to explore whether expression of ZEB1 could be triggered in oral epithelial cells (SG and FaDu) by arecoline in vitro. Control and ZEB1-knockdown arecoline-stimulated SG and FaDu were subjected to migration/invasiveness/anchorage-independent growth assay. Primary and recurrent OSCC tissues from areca quid chewers were analyzed using real-time RT-PCR analysis for ZEB1 expression.

RESULTS

Arecoline led to dose-dependent elevation of ZEB1 expression in SG and FaDu cells. Downregulation of ZEB1 by lentiviral infection significantly reversed arecoline-induced oncogenicity including migration ability, cell invasiveness, and anchorage-independent growth in SG and FaDu cells. Clinically, the level of ZEB1 expression was higher in recurrent OSCC tumor samples but lower in primary lesions.

CONCLUSIONS

Targeting ZEB1 might offer a new strategy for the treatment of OSCC patients. ZEB1 can serve as a progression and relapse marker in OSCC patients.

MicroRNA-150 predicts a favorable prognosis in patients with epithelial ovarian cancer, and inhibits cell invasion and metastasis by suppressing transcriptional repressor ZEB1

MicroRNA (miR)-150 has been reported to be dramatically downregulated in human epithelial ovarian cancer (EOC) tissues and patients’ serum compared to normal controls. This study aimed to investigate clinical significance and molecular mechanisms of miR-150 in EOC. In the current study, quantitative real-time PCR analysis showed that miR-150 was significantly downregulated in human EOC tissues compared to normal tissue samples. Then, we demonstrated the significant associations of miR-150 downregulation with aggressive clinicopathological features of EOC patients, including high clinical stage and pathological grade, and shorter overall and progression-free survivals. More importantly, the multivariate analysis identified miR-150 expression as an independent prognostic biomarker in EOC. After that, luciferase reporter assays demonstrated that Zinc Finger E-Box Binding Homeobox 1 (ZEB1), a crucial regulator of epithelial-to-mesenchymal transition (EMT), was a direct target of miR-150 in EOC cells. Moreover, we found that the ectopic expression of miR-150 could efficiently inhibit cell proliferation, invasion and metastasis by suppressing the expression of ZEB1. Furthermore, we also observed a significantly negative correlation between miR-150 and ZEB1 mRNA expression in EOC tissues (rs = –0.45, P<0.001). In conclusion, these findings offer the convincing evidence that aberrant expression of miR-150 may play a role in tumor progression and prognosis in patients with EOC. Moreover, our data reveal that miR-150 may function as a tumor suppressor and modulate EOC cell proliferation, and invasion by directly and negatively regulating ZEB1, implying the re-expression of miR-150 might be a potential therapeutic strategy for EOC.

Regulation gene expression of miR200c and ZEB1 positively enhances effect of tumor vaccine B16F10/GPI-IL-21 on inhibition of melanoma growth and metastasis

Background

Genetically modified cells have been shown to be one of the most effective tumor vaccine strategies. However, in many cases, such as in melanoma, induction of a potent immune responses against the disease still remains a major challenge. Thus, novel strategies to reinforce tumor vaccine efficacy are needed. Using microRNA (miR) and Zinc-finger E-box binding homeobox (ZEB) have received much attention for potentially regulating tumor progression. To elicit a potent antitumor efficacy against melanoma, we used tumor vaccine in combination with miR200c overexpression or ZEB1 knockdown to assess the efficacy of treatment of murine melanoma.

Methods

B16F10 cell vaccine expressing interleukin 21 (IL-21) in the glycosylpho- sphatidylinositol (GPI)-anchored form (B16F10/GPI-IL-21) were developed. The vaccine was immunized into mice challenged by B16F10 cells or B16F10 cells stably transduced with lentiviral-miR200c (B16F10/miR200c) or transfected with the ZEB1-shRNA recombinant (B16F10/shZEB1) or the B16F10/GPI-IL-21 vaccine. The immune responses, tumorigenicity and lung metastasis in mice were evaluated, respectively.

Results

The vaccination with B16F10/GPI-IL-21 markedly increased the serum cytokine levels of IFN-γ, TNF-α, IL-4 and decreased TGF-β level as well as augmented the cytotoxicity of splenocytes in immunized mice compared with control mice. In addition, the tumor vaccine B16F10/GPI-IL-21 significantly inhibited the tumor growth and reduced counts of lung metastases in mice challenged by B16F10/GPI-IL-21, B16F10/shZEB1 and B16F10/miR200c respectively compared with the control mice challenged by B16F10 cells. The efficacy mechanisms may involve in reinforcing immune responses, increasing expression of miR200c, E-cadherin and SMAD-7 and decreasing expression of TGF-β, ZEB1, Vimentin and N-cadherin in tumor tissues from the immunized mice.

Conclusions

These results indicate that the tumor vaccine B16F10/GPI-IL-21 in combination with miR200c overexpression or ZEB1 knockdown effectively inhibited melanoma growth and metastasis a murine model. Such a strategy may, therefore, be used for the clinical trials.

[Relaxing of unity and membership democracy in the Danish Nursing Council]

Breast cancer patients with high expression of aldehyde dehydrogenases (ALDHs) cell population have higher tolerability to chemotherapy since the cells posses a characteristic of breast cancer stem cells (BCSCs) that are resistant to conventional chemotherapy. In this study, we found that the ALDH‐positive cells were higher in CD44⁺CD24⁻ and CD44⁺CD24⁻ESA⁺BCSCs than that in both BT549 and MDA‐MB‐231 cell lines but microRNA‐7 (miR‐7) level was lower in CD44⁺CD24⁻ and CD44⁺CD24⁻ESA⁺BCSCs than that in MDA‐MB‐231 cells. Moreover, miR‐7 overexpression in MDA‐MB‐231 cells decreased ALDH1A3 activity by miR‐7 directly binding to the 3′‐untranslated region of ALDH1A3; while the ALDH1A3 expression was downregulated in MDA‐MB‐231 cells, the expressions of CD44 and Epithelium Specific Antigen (ESA) were reduced along with decreasing the BCSC subpopulation. Significantly, enforced expression of miR‐7 in CD44⁺CD24⁻ESA⁺BCSC markedly inhibited the BCSC‐driven xenograft growth in mice by decreasing an expression of ALDH1A3. Collectively, the findings demonstrate the miR‐7 inhibits breast cancer growth via suppressing ALDH1A3 activity concomitant with decreasing BCSC subpopulation. This approach may be considered for an investigation on clinical treatment of breast cancers.