Implications of the Notch1-Snail/Slug-epithelial to mesenchymal transition axis for lymph node metastasis in infiltrating ductal carcinoma

A small molecule inhibitor of Notch1 modulates stemness and suppresses breast cancer cell growth

Although breast cancer stem cells (BCSCs) are well characterized, molecularly targeting and eradicating this sub-population remains a challenge in the clinic. Recent studies have explored several signaling pathways that govern stem cell activation: We and others established that the Notch1 signaling plays a significant role in the proliferation, survival, and differentiation of BCSCs. Earlier, we reported that a newly developed small molecule, ASR490, binds to the negative regulatory region (NRR: The activation switch of the Notch receptor) of Notch1. In vitro results demonstrated that ASR490 significantly inhibited BCSCs (ALDH+ and CD44+/CD24-) and breast cancer (BC) growth at nM concentrations, and subsequently inhibited the colony- and mammosphere-forming abilities of BCSCs and BCs. ASR490 downregulated the expressions of Notch1 intracellular domain (NICD: The active form of Notch1) and its downstream effectors Hey1 and HES1. Inhibition of Notch1-NICD facilitated autophagy-mediated growth inhibition by triggering the fusion of autophagosome and autolysosome in BCSCs. ASR490 was found to be non-toxic to healthy cells as compared to existing Notch1 inhibitors. Moreover, oral administration of ASR490 abrogated BCSC and BC tumor growth in the in vivo xenograft models. Together our results indicate that ASR490 is a potential therapeutic agent that inhibits BC tumor growth by targeting and abolishing Notch1 signaling in BCSCs and BC cells.

Exclusion of NUMB Exon12 Controls Cancer Cell Migration through Regulation of Notch1-SMAD3 Crosstalk

NUMB is an endocytic adaptor protein that contains four isoforms (p65, p66, p71 and p72) due to alternative splicing regulation. Here, we show that NUMB exon12 (E12)-skipping isoforms p65/p66 promote epithelial to mesenchymal transition (EMT) and cancer cell migration in vitro, and facilitate cancer metastasis in mice, whereas E12-included p71/p72 isoforms attenuate these effects. Mechanistically, p65/p66 isoforms significantly increase the sorting of Notch1 through early endosomes (EEs) for enhanced Notch1 activity. In contrast, p71/p72 isoforms act as negative regulators of Notch1 by ubiquitylating the Notch1 intracellular domain (N1ICD) and promoting its degradation. Moreover, we observed that the interaction between N1ICD and SMAD3 is important for their own stabilization, and for NUMB-mediated EMT response and cell migration. Either N1ICD or SMAD3 overexpression could significantly recuse the migration reduction seen in the p65/p66 knockdown, and Notch1 or SMAD3 knockdown rescued the migration advantage seen in the overexpression of p66. Taken all together, our study provides mechanistic insights into the opposite regulation of Notch1-SMAD3 crosstalk by NUMB isoforms and identifies them as critical regulators of EMT and cancer cell migration.

Effects of acteoside on the expressions of MCP-1 and TGF-β1 in the diabetic nephropathy mice

Objective: Immune inflammatory cells and cytokines play an important role in the occurrence and development of diabetic nephropathy (DN). Acteoside has been reported to regulate the inflammation and immune response. The study aims to investigate the effects of acteoside on the expressions of MCP-1 and TGF-β1 on nephropathy in diabetic mice.

Methods: C57BL/6J mice in the model group were given a single intraperitoneal injection of STZ (150 mg/kg). Model mice were divided randomly into two groups: 5 without treatment, 5 treated with acteoside. After continuous administration for 8 weeks, serum, urine, and kidney tissue were collected, then, ralated biochemical parameters, pathological characteristics and MCP-1 and TGF-β1 mRNA or protein were detected. The NRK-52E cells were divided into three groups as follows: the normal control group (NC group), the high glucose group (HS group), the high glucose+acteoside group (HS+ACT group). The expressions of MCP-1 and TGF-β1 in the mRNA and protein levels were assessed with RT-PCR, western blot and ELISA.

Results: The expressions of MCP-1 and TGF-β1 were significantly enhanced in DN group and dramatically reduced after acteoside treatment. Compared with those in NC group, the expressions of MCP-1 and TGF-β1 in NRK-52E cell of HS group were significantly enhanced, while both were significantly decreased in HS+ACT group compared with HS group.

Conclusion: Our findings indicate that Acteoside has protective effects on DN via inhibiting the expressions of MCP-1 and TGF-β1.

Novel Ellipsoid Chitosan-Phthalate Lecithin Nanoparticles for siRNA Delivery

Small interfering RNA (siRNA) has received increased interest as a gene therapeutic agent. However, instability and lack of safe, affordable, and effective carrier systems limit siRNA's widespread clinical use. To tackle this issue, synthetic vectors such as liposomes and polymeric nanoparticles have recently been extensively investigated. In this study, we exploited the advantages of reduced cytotoxicity and enhanced cellular penetration of chitosan-phthalate (CSP) together with the merits of lecithin (LC)-based nanoparticles (NPs) to create novel, ellipsoid, non-cytotoxic, tripolyphosphate (TPP)-crosslinked NPs capable of delivering siRNA efficiently. The resulting NPs were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM), and were found to be ellipsoid in the shape of ca. 180 nm in size, exhibiting novel double-layer shells, with excellent stability at physiological pH and in serum solutions. MTT assay and confocal fluorescence microscopy showed that CSP-LC-TPP NPs are non-cytotoxic and efficiently penetrate cancer cells in vitro. They achieved 44% silencing against SLUG protein in MDA-MB-453 cancer cells and were significantly superior to a commercial liposome-based transfection agent that achieved only 30% silencing under comparable conditions. Moreover, the NPs protected their siRNA cargos in 50% serum and from being displaced by variable concentrations of heparin. In fact, CSP-LC-TPP NPs achieved 26% transfection efficiency in serum containing cell culture media. Real-time wide-field fluorescence microscopy showed siRNA-loaded CSP-LC-TPP NPs to successfully release their cargo intracellularly. We found that the amphoteric nature of chitosan-phthalate polymer promotes the endosomal escape of siRNA and improves the silencing efficiency.

Snail-Family Proteins: Role in Carcinogenesis and Prospects for Antitumor Therapy

The review analyzes Snail family proteins, which are transcription factors involved in the regulation of the epithelial-mesenchymal transition (EMT) of tumor cells. We describe the structure of these proteins, their post-translational modification, and the mechanisms of Snail-dependent regulation of genes. The role of Snail proteins in carcinogenesis, invasion, and metastasis is analyzed. Furthermore, we focus on EMT signaling mechanisms involving Snail proteins. Next, we dissect Snail signaling in hypoxia, a condition that complicates anticancer treatment. Finally, we offer classes of chemical compounds capable of down-regulating the transcriptional activity of Snails. Given the important role of Snail proteins in cancer biology and the potential for pharmacological inhibition, Snail family proteins may be considered promising as therapeutic targets.

Role of microRNA-33a in malignant cells

Cancer causes most of the mortality and morbidity worldwide, with a significant increase in incidence during recent years. MicroRNAs (miRNAs/miRs) are non-coding small RNAs capable of regulating gene expression. They regulate crucial cellular processes, including proliferation, differentiation, metastasis and apoptosis. Therefore, abnormal miRNA expression is associated with multiple diseases, including cancer. There are two types of cancer-associated miRNAs, oncogenic and tumor suppressor miRNAs, depending on their roles and expression patterns in cancer. Accordingly, miRNAs are considered to be targets for cancer prevention and treatment. miR-33a controls cellular cholesterol uptake and synthesis, which are both closely associated with carcinogenesis. The present review thoroughly describes the roles of miR-33a in more than a dozen types of cancer and the underlying mechanisms. Accordingly, the present review may serve as a guide for researchers studying the involvement of miR-33a in diverse cancer settings.

Effect of miR‑449a‑mediated Notch signaling pathway on the proliferation, apoptosis and invasion of papillary thyroid carcinoma cells

The present study aimed to investigate the effect of miR‑449a‑mediated Notch signaling pathway on the proliferation, apoptosis and invasion of papillary thyroid carcinoma cells. Human papillary thyroid carcinoma cell line TPC‑1 was selected, and cells were grouped and transfected: Control group (without any treatment), negative control (NC) group (transfection with NC plasmid), miR‑449a mimic group (transfection with miR‑449a mimic), miR‑449a inhibitor group (transfection with miR‑449a inhibitor), DAPT group (addition of γ‑secretase inhibitor DAPT to inhibit the Notch signaling pathway), and miR‑449a inhibitor + DAPT group (transfection with miR‑449a inhibitor and addition of DAPT). The target relationship between miR‑449a and Notch1 was detected by dual‑luciferase reporter assay. qRT‑PCR and western blotting were used to assess the expression of miR‑449a, Notch1 and Jagged1 in cells. Cell proliferation was detected using EdU; the cell cycle and apoptosis were detected by flow cytometry; cell invasion ability was detected by Transwell assay. PCNA, MMP‑2, MMP‑9, Bcl‑2 and Bax mRNA and protein expression were assessed by qRT‑PCR and western blotting. The results revealed that miR‑449a negatively regulated Notch1. Compared with the control group, there was significantly increased miR‑449a expression in the miR‑449a mimic group, and there was significantly decreased expression of Notch1, Jagged1, PCNA, MMP‑2, MMP‑9 and Bcl‑2, increased Bax, reduced cell proliferation, increased G1‑phase cell fraction, decreased S‑phase cell fraction, an increased apoptosis rate, and decreased invasion ability in the miR‑449a mimic group and DAPT group (all P<0.05). However, the results in the miR‑449a inhibitor group were the opposite of those in miR‑449a mimic group (all P<0.05). There was no significant difference in cell proliferation, apoptosis and invasion in the NC group and miR‑449a inhibitor + DAPT group compared to the control group (all P>0.05). miR‑449a overexpression can inhibit Notch signaling pathway, thereby inhibiting the proliferation and invasion of papillary thyroid carcinoma cells and promoting cell apoptosis.

microRNA-33a prevents epithelial-mesenchymal transition, invasion, and metastasis of gastric cancer cells through the Snail/Slug pathway

Invasion and metastasis are responsible for the majority of deaths in gastric cancer (GC). microRNA-33a (miR-33a) might function as a tumor suppressor in multiple cancers. Here, we describe the regulation and function of miR-33a in GC and mechanisms involved in epithelial-mesenchymal transition (EMT) and metastasis. First, GC tissues and adjacent normal tissues were collected. miR-33a upregulation or SNAI2 depletion on GC cells were introduced to assess the detailed regulatory mechanism of them. We assessed the expression of miR-33a, SNAI2, Snail/Slug signaling pathway-related genes, and EMT-related markers in GC tissues and cells. miR-33a distribution in GC tissues and adjacent normal tissues was measured. Cell proliferation, migration and invasion, and cell cycle distribution were assessed. In nude mice, GC tumor growth and lymph node metastasis were observed. Furthermore, the predicative value of miR-33a in the prognosis of GC patients was evaluated. The obtained results indicated that lowly expressed miR-33a, highly expressed SNAI2, activated Snail/Slug, and increased EMT were identified in GC tissues. miR-33a was located mainly in the cytoplasm. miR-33a targeted and negatively regulated SNAI2. MKN-45 and MKN-28 cell lines were selected for in vitro experiments. Upregulated miR-33a expression or siRNA-mediated silencing of SNAI2 suppressed the activation of Snail/Slug, whereby GC cell proliferation, invasion and migration, EMT, tumor growth, and lymph node metastasis were inhibited. High expression of miR-33a was a protective factor influencing the prognosis of GC. This study suggests that miR-33a inhibited EMT, invasion, and metastasis of GC through the Snail/Slug signaling pathway by modulating SNAI2 expression.NEW & NOTEWORTHY miR-33a targets and inhibits the expression of SNAI2, overexpression of SNAI2 activates the Snail/Slug signaling pathway, the Snail/Slug signaling pathway promotes GC cell proliferation, invasion, and metastasis, and overexpression of miR-33a inhibits cell proliferation, invasion, and metastasis. This study provides a new therapeutic target for the treatment of GC.

Rhamnetin induces apoptosis in human breast cancer cells via the miR-34a/Notch-1 signaling pathway

The present study aimed to investigate whether rhamnetin induced apoptosis in human breast cancer cells and the underlying molecular mechanism of this anti cancer effect. The treatment of MCF-7 cells with rhamnetin was able to significantly inhibit cell proliferation and induce caspase-3/9 activity in a dose- and time-dependent manner, compared with untreated cells. In addition, treatment with rhamnetin was able to significantly promote the expression of p53 protein and microRNA (miR-)34a compared with untreated cells. The treatment with rhamnetin also suppressed the expression of Notch1 protein in MCF-7 cells compared with untreated cells. Subsequently, miR-24a expression was promoted in rhamnetin-treated MCF-7 cells using a miR-34a plasmid. The overexpression of miR-34a was able to significantly inhibit cell viability and induce caspase-3/9 activity in MCF-7 cells following treatment with rhamnetin. Furthermore, the overexpression of miR-34a was able to significantly promote the expression of p53 protein and miR-34a, and suppress the expression of Notch1 protein in rhamnetin-treated MCF-7 cells. Therefore, the results of the present study demonstrated that rhamnetin induced apoptosis in human breast cancer cells via the miR-34a/Notch-1 signaling pathway.

Cypripedin diminishes an epithelial-to-mesenchymal transition in non-small cell lung cancer cells through suppression of Akt/GSK-3β signalling

Lung cancer appears to have the highest rate of mortality among cancers due to its metastasis capability. To achieve metastasis, cancer cells acquire the ability to undergo a switch from epithelial to mesenchymal behaviour, termed the epithelial-to-mesenchymal transition (EMT), which is associated with poor clinical outcomes. Drug discovery attempts have been made to find potent compounds that will suppress EMT. Cypripedin, a phenanthrenequinone isolated from Thai orchid, Dendrobium densiflorum, exhibits diverse pharmacological activities. In this study, we found that cypripedin attenuated typical mesenchymal phenotypes, including migratory behaviour, of non-small cell lung cancer H460 cells, with a significant reduction of actin stress fibres and focal adhesion and with weakened anchorage-independent growth. Western blot analysis revealed that the negative activity of this compound on EMT was a result of the down-regulation of the EMT markers Slug, N-Cadherin and Vimentin, which was due to ATP-dependent tyrosine kinase (Akt) inactivation. As a consequence, the increase in the Slug degradation rate via a ubiquitin-proteasomal mechanism was encouraged. The observation in another lung cancer H23 cell line also supported this finding, indicating that cypripedin exhibits a promising pharmacological action on lung cancer metastasis that could provide scientific evidence for the further development of this compound.

High snail expression predicts a poor prognosis in breast invasive ductal carcinoma patients with HER2/EGFR-positive subtypes

BACKGROUND

High Snail expression is known as a poor prognostic factor in breast cancer. However, its prognostic impact for breast cancer with different molecular subtypes is still controversial.

METHODS

Snail expression was examined by immunohistochemistry in tissue microarray slides of 85 corresponding tumor-adjacent normal (CTAN) and 247 breast invasive ductal carcinoma (IDC) tissues. Multivariable Cox regression analysis was used to assess the impact of Snail expression on survival rate by different molecular subtypes of breast IDC patients.

RESULTS

The level of Snail expression in IDC tumor tissues was significantly higher than that in CTAN tissues. Moreover, high Snail expression had direct impacts on poor disease specific survival (DSS) and disease-free survival (DFS) in breast IDC patients with human epidermal growth factor receptor 2 (HER2)-positive and human epidermal growth factor receptor (EGFR)-positive statuses as well as the HER2 intrinsic subtype. Additionally, breast IDC patients with a combination of three prognostic factors, including high Snail expression and HER2-positive and EGFR-positive statuses, had much poor DSS and DFS with a statistically significant linear trend.

CONCLUSION

High Snail expression could predict a poor prognosis for breast IDC patients with HER2/EGFR-positive subtypes.

Upregulated N-cadherin expression is associated with poor prognosis in epithelial-derived solid tumours: A meta-analysis

BACKGROUND

N-cadherin is an important molecular in epithelial-mesenchymal transition (EMT) and has been reported to be associated with aggressive behaviours of tumours. However, prognostic value of N-cadherin in solid malignancies remains controversially.

MATERIALS AND METHODS

The Pubmed/MELINE and EMBASE databases were used for a comprehensive literature searching. Pooled risk ratio (RR) and hazard ratio (HR) with their corresponding 95% confidence intervals (CIs) were employed to quantify the prognostic role.

RESULTS

Involving 36 studies with 5705 patients were performed to investigate relationships between N-cadherin upregulation and clinicopathological features, survival. Results suggested upregulated N-cadherin was associated with lymph node metastasis (RR = 1.16, 95% CI [1.00, 1.35]), higher histological grade (RR = 1.36, 95%CI [1.14, 1.62]), angiolymphatic invasion (RR = 1.19, 95% CI [1.06, 1.34]) and advanced clinical stage (RR = 1.32, 95% CI [1.06, 1.64]), while upregulated N-cadherin was apt to be associated with distant metastasis (RR = 1.43, 95% CI [0.99, 2.05]). Moreover, N-cadherin was correlated with poor prognosis of 3-year survival (HR = 1.78, 95% CI [1.51, 2.10]), 5-year survival (HR = 1.57, 95% CI [1.17, 2.10]) and overall survival (OS) (HR = 1.32, 95% CI [1.20, 1.44]). Subgroup analyses according to cancer types were also conducted for applying these conclusions to some tumours more properly. No publication bias was found except subgroup analysis of distant metastasis (P = .652 for Begg's test and 0.023 for Egger's test).

CONCLUSIONS

Taken together, upregulation of N-cadherin is associated with more aggressive behaviours of epithelial-derived solid malignancies and can be regarded as a predictor of poor survival.

A novel Notch1 missense mutation (C1133Y) in the Abruptex domain exhibits enhanced proliferation and invasion in oral squamous cell carcinoma

Background

Notch1 has been regarded as a fundamental regulator in tissue differentiation and stem cell properties. Recently, Notch1 mutations have been reported intensively both in solid tumors and in hematopoietic malignancies. However, little is known about the biological effect and the clinical implication of these reported mutations. Previously, we discovered several missense mutations in the Notch1 receptor in a Chinese population with oral squamous cell carcinoma (OSCC).

Methods

We selected a ‘hotspot’ mutation in the Abruptex domain (C1133Y). The expression of Notch1 was determined by western blot and real-time qPCR in OSCC cell lines transfected with pcDNA3.1-Notch1^WT, pcDNA3.1-Notch1^C1133Y, or pcDNA3.1 empty vector. CCK-8 assays were used to assess cell proliferation. Flow cytometry and western blot were used to confirm the alteration of cell cycle after transfection. Transwell assays and the detection of Epithelial-to-mesenchymal transition (EMT) markers were used to determine the invasive ability. The effects of Notch1 C1133Y mutation were analyzed by Immunofluorescence staining and the expression of EGFR-PI3K/AKT signaling.

Results

We demonstrated that Notch1^C1133Y mutation inactivated the canonical Notch1 signaling. We identified an oncogenic phenotype of this mutation by promoting cell proliferation, invasion and by inducing EMT in OSCC cell lines. We found that the Notch1^C1133Y mutation exhibited a decreased S1-cleavage due to the impaired transport of Notch1 protein from the endoplasmic reticulum (ER) to the Golgi complex, which was consistent with the observation of the failure of the Notch1^C1133Y mutated receptor to present at the cell surface. Importantly, the mutated Notch1 activated the EGFR-PI3K/AKT signaling pathway, which has been confirmed as an overwhelming modulator in OSCC.

Conclusions

Taken together, our findings revealed for the first time a novel Notch1 mutation that enhances proliferation and invasion in OSCC cell lines. The Notch1 C1133Y mutation impairs the processing of notch1 protein and the critical links between the mutated Notch1 and the activated EGFR-PI3K/AKT signaling pathway.

Electronic supplementary material

The online version of this article (10.1186/s12935-017-0496-5) contains supplementary material, which is available to authorized users.

Loss of Kaiso expression in breast cancer cells prevents intra-vascular invasion in the lung and secondary metastasis

The metastatic activity of breast carcinomas results from complex genetic changes in epithelial tumor cells and accounts for 90% of deaths in affected patients. Although the invasion of the local lymphatic vessels and veins by malignant breast tumor cells and their subsequent metastasis to the lung, has been recognized, the mechanisms behind the metastatic activity of breast tumor cells to other distal organs and the pathogenesis of metastatic cancer are not well understood. In this study, we utilized derivatives of the well-established and highly metastatic triple negative breast cancer (TNBC) cell line MDA-MB-231 (MDA-231) to study breast tumor metastasis in a mouse model. These MDA-231 derivatives had depleted expression of Kaiso, a POZ-ZF transcription factor that is highly expressed in malignant, triple negative breast cancers. We previously reported that Kaiso depletion attenuates the metastasis of xenografted MDA-231 cells. Herein, we describe the pathological features of the metastatic activity of parental (Kaiso^positive) versus Kaiso^depleted MDA-231 cells. Both Kaiso^positive and Kaiso^depleted MDA-231 cells metastasized from the original tumor in the mammary fat pad to the lung. However, while Kaiso^positive cells formed large masses in the lung parenchyma, invaded large pulmonary blood vessels and formed secondary metastases and large tumors in the distal organs, Kaiso^depleted cells metastasized only to the lung where they formed small metastatic lesions. Importantly, intravascular invasion and secondary metastases in distal organs were not observed in mice xenografted with Kaiso^depleted cells. It thus appears that the lung may constitute a barrier for less invasive breast tumors such as the Kaiso^depleted TNBC cells; this barrier may limit tumor growth and prevents Kaiso^depleted TNBC cells from invading the pulmonary blood vessels and forming secondary metastases in distal organs.

Overexpression of Pofut1 and activated Notch1 may be associated with poor prognosis in breast cancer

PURPOSE

The present study was to evaluate the prognostic value of protein expression of Pofut1 and Notch1 signaling in breast cancer.

MATERIAL AND METHODS

Formalin-fixed paraffin-embedded 314 breast specimens including 174 infiltrating ductal carcinoma(IDC), 50 ductal carcinoma in situ(DCIS) and 90 adjacent normal tissue(ANT) were immunohistochemically examined to evaluate the protein expression of Pofut1, activated Notch1(N1IC) and Slug on specimens. Survival analysis was performed by Kaplan-Meier method and Cox's proportional-hazards model. A online database was computationally used to further explore the prognostic role of Pofut1 and Notch1 mRNA expression by Kaplan-Meier Plotter.

RESULTS

Pofut1, Slug and N1IC expression were significantly increased in IDC compared to ANT(all p < 0.05). High expression of Pofut1, Slug and N1IC were associated with tumor aggressiveness including lymph node metastasis (LNM: p = 0.005 for Pofut1, p < 0.001 for N1IC, p = 0.017 for Slug), advanced stage(p = 0.039 for Pofut1, p = 0.025 for N1IC) and higher histological grade(p = 0.001 for N1IC). Additionally, high expression of Pofut1 was found to be significantly associated with high expressions of N1IC and Slug in IDC(r = 0.244, p = 0.001; r = 0.374, p < 0.001, respectively), similar correlation was also observed between high N1IC and Slug expression(r = 0.496, p < 0.001). Moreover, Kaplan-Meier and Cox's regression analysis indicated the significant prognostic value of elevated Pofut1, N1IC, Slug expressions, positive LNM and advanced tumor stage for the prediction of a shorter disease-free survival (DFS) and overall survival(OS). The web-based analysis also suggested a significant association of high Pofut1 and Notch1 mRNA expression with worse survival outcome.

CONCLUSION

Our findings suggested that overexpression of Pofut1 and activated Notch1 signaling may be associated with a poor prognosis in breast cancer.

Triple-negative breast cancer: New therapeutic options via signalling transduction cascades

Triple-negative breast cancer is a highly aggressive type of mammalian carcinoma. It is defined by a rather weak expression of estrogen-, progesterone- and Her2-receptor, and is thus difficult to treat, resulting in low disease-free and overall survival rates of the affected patients. Hence it is important to find new therapeutic options. To this aim we analysed the incidence of some molecules from different signal transduction cascades by immunohistochemistry, which are known to correlate with triple-negative breast cancer, and correlated the expression of these molecules to different tumour traits, such as size, grading, menopausal stage, histology, lymph node affection, remote metastasis formation, and to the incidence of local and lymph node recurrence and metastasis by statistical analysis. Statistically significant correlations were found for a number of tumour characteristics and signalling molecules: HIF1α is correlated to tumour grading, β-catenin to the menopausal state of the patient, and for Notch1 a relation to lymph node affection is seen. In terms of different recurrences, a correlation of β-catenin to metastasis formation and lymph node affection could be shown, as well as coherences between XBP1 and lymph node recurrence, Notch1 and metastasis formation and FOXP3 and the occurrence of local recurrence. The presented results are in accordance with formerly published studies and therefore might comprise opportunities to develop new therapeutical strategies, which could help to handle this aggressive form of breast cancer in a manner, by which side effects would be reduced and therapeutical efficiency is increased.

Targeting aberrant expression of Notch-1 in ALDH+ cancer stem cells in breast cancer

We have previously reported that high aldehyde dehydrogenase (ALDH) enzyme activity in breast cancer cells results in breast cancer stem cell (BCSC) properties by upregualting Notch-1 and epithelial mesenchymal markers. This results in chemoresistance in breast cancer. Here, we examined the functional and clinical significance of ALDH expression by measuring the ALDH levels in breast cancer tissues by immunohistochemistry. There was a significantly higher ALDH expression in higher grade breast cancer tumor tissues (Grade- II and III) versus normal breast tissues. Injection of BCSC (ALDH⁺ and CD44⁺ /CD22^- ) cells resulted in aggressive tumor growth in athymic mice versus ALDH^- cells. The ALDH⁺ and CD44⁺ /CD22^- tumors grow rapidly and are larger than ALDH^- tumors which were slow growing and smaller. Molecularly, ALDH⁺ tumors expressed higher expression of Notch-1 and EMT markers than ALDH^- tumors. Oral administration of the naturally occurring Psoralidin (Pso, 25 mg/kg of body weight) significantly inhibited the growth in ALDH⁺ and ALDH^- tumors as well. Psoralidin inhibited Notch-1 mediated EMT activation in ALDH⁺ and ALDH^- tumors-this confirms our in vitro findings. Our results suggest that Notch-1 could be an attractive target and inhibition of Notch-1 by Psoralidin may prevent pathogenesis of breast cancer as well as metastasis. © 2016 Wiley Periodicals, Inc.

The Role of Notch1 Signaling in Anaplastic Thyroid Carcinoma

PURPOSE

The Notch signaling pathway is widely expressed in normal, reactive, and neoplastic tissues; however, its role in thyroid tissues has not been fully elucidated. Therefore, this study was conducted to characterize the expression of the Notch signaling pathway in papillary thyroid cancer (PTC) cells and anaplastic thyroid cancer (ATC) cells.

MATERIALS AND METHODS

Expression of activated Notch1 in ATC and PTC paraffin-embedded tissues was determined by immunohistochemistry. The small interfering RNA techniquewas employed to knock down Notch1 expression in ATC and PTC cell lines.

RESULTS

The expression of activated Notch1 was higher in ATC cases than in PTC cases. Inhibition of Notch1 significantly reduced proliferation and migration of ATC cells, but not PTC cells. In addition, inhibition of Notch1 in ATC cells significantly reduced the expression of key markers of epithelial-mesenchymal transition and cancer stem cells. Conversely, changes in the expression of these proteins were not observed in PTC cells.

CONCLUSION

The results of this study suggest that Notch1 expression plays different roles in tumor progression in ATC and PTC cells. We also found that Notch1 expression was significantly related to the highly invasive or proliferative activity of ATC cells.

Role of Snail in regulation of intestinal epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT) is involved in many pathological processes such as tissue fibrosis, tumor occurrence and metastasis, which has become one of current research focuses. The transcription factor Snail is a C₂H₂-type zinc finger protein and has a crucial regulatory role in EMT through the transcription inhibition region, which is composed of SNAG domain and C-terminal binding protein, to inhibit the expression of genes. Recently, numerous studies have confirmed that Snail can promote EMT through the tumor necrosis factor α (TNF-α)-nuclear factor κB (NF-κB)- Snail pathway and transforming growth factor β1 (TGF-β1)-Smads-Snail pathway. This article aims to summarize the regulatory role of Snail in mediating intestinal EMT via the above two

pathways.

The Relationship Between E-Cadherin and its Transcriptional Repressors in Spontaneously Arising Canine Invasive Micropapillary Mammary Carcinoma

E-cadherin downregulation is related to metastatic behaviour and a poor prognosis in cancer. It might be induced by transcriptional repression mediated by the transcription factors SNAIL, ZEB1, ZEB2 and TWIST. Here, we investigated E-cadherin expression and its relationship to those transcriptional repressors (i.e. SNAIL, ZEB1, ZEB2 and TWIST) in the progression from carcinoma 'in situ' to invasion to lymph node metastasis in spontaneously arising canine invasive micropapillary carcinoma (IMPC). E-cadherin expression decreased from carcinoma in situ to invasive progression and was likely to increase with lymph node metastasis. Expression of SNAIL decreased from carcinoma in situ to invasive areas and from invasive areas to lymph nodes. Metastatic lymph nodes had higher expression of ZEB1 than carcinoma in situ and invasive areas. ZEB2 expression was observed in 52%, 38% and 33% of carcinoma in situ areas, invasive areas and lymph node metastases, respectively. TWIST expression was observed in 52%, 38% and 33% of carcinoma in situ areas, invasive areas and lymph node metastases, respectively. In invasive areas, E-cadherin downregulation correlated significantly with SNAIL and TWIST upregulation. Additionally, in infiltrating components of IMPCs, E-cadherin(-)SNAIL(+) neoplastic epithelial cells were observed by immunofluorescence. Taken together, canine mammary IMPCs had a loss of E-cadherin from carcinoma in situ to invasive areas, which appears to be induced by the transcription factor SNAIL. In lymph node metastasis, ZEB1 appears to not exert E-cadherin transcriptional repression activity.