Tsung-Hua Hsieh

Phthalates induce proliferation and invasiveness of estrogen receptor-negative breast cancer through the AhR/HDAC6/c-Myc signaling pathway

The environmentally present group of chemical phthalates, or phthalate esters, has been recognized as a rising threat to public health, including cancer. While most studies have addressed the estrogenic effects of phthalates in malignancies of the breast and the prostate, little is known about their role in the etiology of hormone‐independent cancer. Here we show that treatments with the phthalates n‐butyl benzyl phthalate (BBP) and dibutyl phthalate (DBP) at 1 μM induced proliferation (BBP, 3.2‐fold; DBP, 3.2‐fold), migration (BBP, 2.6‐fold; DBP, 2.6‐fold), invasion (BBP, 2.7‐fold; DBP, 3.1‐fold), and tumor formation (EC50: BBP, 0.12 μM; DBP, 0.22 μM) in estrogen receptor (ER)‐negative breast cancer cells (MDA‐MB‐231). We further demonstrate that phthalates stimulated the cell surface aryl hydrocarbon receptor (AhR) and triggered the downstream cyclic AMP (cAMP)‐PKA‐CREB1 signaling cascade. The pathway led to increased expression of HDAC6, which facilitated nuclear assembly of the β‐catenin‐LEF1/TCF4 transcriptional complex and transactivation of the c‐Myc oncogene. This nongenomic pathway emanated from the phthalateinduced AhR promoted tumorigenesis of ER‐negative breast cancer. Collectively, our findings revealed a novel oncogenic mechanism of phthalates in breast cancer independent from their estrogenic activities.—Hsieh, T.‐H., Tsai, C.‐F., Hsu, C.‐Y., Kuo, P.‐L., Lee, J.‐N., Chai, C.‐Y., Wang, S.‐C., Tsai, E.‐M. Phthalates induce proliferation and invasiveness of estrogen receptor‐negative breast cancer through the AhR/HDAC6/c‐Myc signaling pathway. FASEB J. 26, 778–787 (2012). www.fasebj.org

Comparative study of human eutopic and ectopic endometrial mesenchymal stem cells and the development of an in vivo endometriotic invasion model

OBJECTIVE To elucidate the role of endometrial stem-progenitor cells in the etiology of endometriosis and to develop an animal model to study the invasion ability of endometrial cells. DESIGN Gene expression and cell function studies were designed. SETTING Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan. PATIENT(S) Human endometrial mesenchymal stem cells (MSCs) were isolated from 22 different endometrium biopsies after surgery for treatment of endometriosis. INTERVENTION(S) Endometrial MSCs developed from eutopic and ectopic endometrial tissues. MAIN OUTCOME MEASURE(S) Characterization of MSC phenotypes (i.e., differentiation induction and gene expression by flow cytometric analysis); comparative study of cell functions (i.e., cell growth, migration, and invasion assays). The invasion of implants in an animal model was examined by histologic staining. RESULT(S) We compared the characteristics of eutopic and ectopic endometrial MSCs from the same endometrial donor. Although both showed similar mesenchymal cell phenotypes, ectopic endometrial MSCs showed distinctly greater ability of cell migration and invasion. Furthermore, in an in vivo cell invasion model using cells grown in scaffold and transplantation in immune-deficient mice, the ectopic endometrial MSCs were found to form many new blood vessels and to invade surrounding tissue. CONCLUSION(S) These results indicate unique invasion and angiogenesis characteristics of ectopic endometrial MSCs that may underlie the pathogenesis of ectopic endometriosis. The animal invasion model will be useful for future characterization of endometrial MSCs.

miRNA-199a-5p regulates VEGFA in endometrial mesenchymal stem cells and contributes to the pathogenesis of endometriosis.

It is believed that endometrial miRNAs contribute to the aetiology of endometriosis in stem cells; however, the mechanisms remain unclear. Here we collected serum samples from patients with or without endometriosis and characterized the miRNA expression profiles of these two groups. MicroRNA‐199a‐5p (miR‐199a‐5p) was dramatically down‐regulated in patients with endometriosis compared with control patients. In addition, we found that the tumour suppressor gene, SMAD4, could elevate miR‐199a‐5p expression in ectopic endometrial mesenchymal stem cells. Up‐regulation of miR‐199a‐5p suppressed cell proliferation, motility and angiogenesis of these ectopic stem cells by targeting the 3′ untranslated region of VEGFA. Furthermore, we established an animal model of endometriosis and found that miR‐199a‐5p could decrease the size of endometriotic lesions in vivo. Taken together, this newly identified miR‐199a‐5p module provides a new avenue to the understanding of the processes of endometriosis development, especially proliferation, motility and angiogenesis, and may facilitate the development of potential therapeutics against endometriosis. Copyright

n-Butyl Benzyl Phthalate Promotes Breast Cancer Progression by Inducing Expression of Lymphoid Enhancer Factor 1

Environmental hormones play important roles in regulating the expression of genes involved in cell proliferation, drug resistance, and breast cancer risk; however, their precise role in human breast cancer cells during cancer progression remains unclear. To elucidate the effect of the most widely used industrial phthalate, n-butyl benzyl phthalate (BBP), on cancer progression, we evaluated the results of BBP treatment using a whole human genome cDNA microarray and MetaCore software and selected candidate genes whose expression was changed by more than ten-fold by BBP compared with controls to analyze the signaling pathways in human breast cancer initiating cells (R2d). A total of 473 genes were upregulated, and 468 were downregulated. Most of these genes are involved in proliferation, epithelial-mesenchymal transition, and angiogenesis signaling. BBP induced the viability, invasion and migration, and tube formation in vitro, and Matrigel plug angiogenesis in vivo of R2d and MCF-7. Furthermore, the viability and invasion and migration of these cell lines following BBP treatment was reduced by transfection with a small interfering RNA targeting the mRNA for lymphoid enhancer-binding factor 1; notably, the altered expression of this gene consistently differentiated tumors expressing genes involved in proliferation, epithelial-mesenchymal transition, and angiogenesis. These findings contribute to our understanding of the molecular impact of the environmental hormone BBP and suggest possible strategies for preventing and treating human breast cancer.

Phthalates Stimulate the Epithelial to Mesenchymal TransitionThrough an HDAC6-Dependent Mechanism in Human BreastEpithelial Stem Cells

Phthalates are environmental hormone-like molecules that are associated with breast cancer risk and are involved in metastasis, a process that requires the epithelial-mesenchymal transition (EMT). However, few studies have addressed the potential effects of phthalates on stem cells. Here we tested the hypothesis that phthalates such as butyl benzyl phthalate and di-n-butyl phthalate induce EMT in R2d cells, a stem cell-derived human breast epithelial cell line that is responsive to estradiol for tumor development. We observed that phthalates induced EMT as evidenced by morphological changes concomitant with increased expression of mesenchymal markers and decreased expression of epithelial markers. Molecular mechanism studies revealed that histone deacetylase 6 (HDAC6) is required for phthalate-induced cell migration and invasion during EMT in vitro and metastasis into the lungs of nude mice. We also constructed a series of mutant HDAC6 promoter fragments and found that the transcription factor AP-2a plays a novel role in regulating the HDAC6 promoter. Furthermore, phthalates stimulated estrogen receptors and triggered the downstream EGFR-PKA signaling cascade, leading to increased expression of AP-2a in the nucleus. We also observed that phthalates increased expression of the PP1/HDAC6 complex and caused Akt activation and GSK3β inactivation, leading to transcriptional activation of vimentin through the β-catenin-TCF-4/LEF1 pathway. Understanding the signaling cascades of phthalates that activate EMT through HDAC6 in breast epithelial stem cells provides the identification of novel therapeutic target for human breast cancer.

Serum Level of IL-10 Is Increased in Patients with Endometriosis, and IL-10 Promotes the Growth of Lesions in a Murine Model

Immune dysregulation may be involved in the development of endometriosis. The anti-inflammatory cytokine IL-10 plays an important role in eliminating unwanted cells and cellular debris in a silent way. We investigated the modulatory role of IL-10 in the development of endometriosis. We observed that the serum level of IL-10 in patients with endometriosis was significantly higher than that in healthy subjects or in control subjects with other gynecological disease. Monocyte-derived dendritic cells acquired from male donors and subsequently conditioned with serum from women with endometriosis exhibited a tolerogenic phenotype, including increased IL-10 production, lower IL-12 secretion, and down-regulation of CD86 and HLA-DR molecules. Depletion of IL-10 activity in a C57BL/6 mouse model of surgically induced endometriosis significantly decreased the size of endometrial lesions. In contrast, IL-10 administration promoted the growth of endometrial lesions in this model. In addition, infiltrated plasmacytoid dendritic cells were the primary IL-10-secreting immune cells in endometrial lesions. Our findings suggest that IL-10 may suppress immunity against endometrial implants, contributing to development of endometriosis.

Targeted next-generation sequencing for molecular diagnosis of endometriosis-associated ovarian cancer

Recent molecular and pathological studies suggest that endometriosis may serve as a precursor of ovarian cancer (endometriosis-associated ovarian cancer, EAOC), especially of the endometrioid and clear cell subtypes. Accordingly, this study had two cardinal aims: first, to obtain mutation profiles of EAOC from Taiwanese patients; and second, to determine whether somatic mutations present in EAOC can be detected in preneoplastic lesions. Formalin-fixed paraffin-embedded (FFPE) tissues were obtained from ten endometriosis patients with malignant transformation. Macrodissection was performed to separate four different types of cells from FFPE sections in six patients. The four types of samples included normal endometrium, ectopic endometriotic lesion, atypical endometriosis, and carcinoma. Ultra-deep (>1000×) targeted sequencing was performed on 409 cancer-related genes to identify pathogenic mutations associated with EAOC. The most frequently mutated genes were PIK3CA (6/10) and ARID1A (5/10). Other recurrently mutated genes included ETS1, MLH1, PRKDC (3/10 each), and AMER1, ARID2, BCL11A, CREBBP, ERBB2, EXT1, FANCD2, MSH6, NF1, NOTCH1, NUMA1, PDE4DIP, PPP2R1A, RNF213, and SYNE1 (2/10 each). Importantly, in five of the six patients, identical somatic mutations were detected in atypical endometriosis and tumor lesions. In two patients, genetic alterations were also detected in ectopic endometriotic lesions, indicating the presence of genetic alterations in preneoplastic lesion. Genetic analysis in preneoplastic lesions may help to identify high-risk patients at early stage of malignant transformation and also shed new light on fundamental aspects of the molecular pathogenesis of EAOC.Key messagesMolecular characterization of endometriosis-associated ovarian cancer genes by targeted NGS.Candidate genes predictive of malignant transformation were identified.Chromatin remodeling, PI3K-AKT-mTOR, Notch signaling, and Wnt/β-catenin pathway may promote cell malignant transformation.

Possible mechanism of phthalates-induced tumorigenesis

Phthalates—substances used in the manufacture of plastics—are considered as possible human carcinogens and tumor‐promoting agents. The worldwide annual production of plastics surpassed 300 million tons in 2010. Plastics are an indispensable material in modern society, and many products manufactured from plastics are a boon to public health; however, plastics also pose health risks. Animal studies have indicated that phthalates are carcinogenic, but human epidemiological data confirming this carcinogenicity in humans are limited. The activation of peroxisome proliferator‐activated receptor α (PPARα), which has been observed in rodent carcinogenesis, has not been observed in humans. Here, we review the hypothesis that the aryl hydrocarbon receptor (AhR) and its downstream signaling cascade promote phthalate‐induced tumorigenesis.

A novel cell-penetrating peptide suppresses breast tumorigenesis by inhibiting β-catenin/LEF-1 signaling

The inhibition of β-catenin/LEF-1 signaling is an emerging strategy in cancer therapy. However, clinical targeted treatment of the β-catenin/LEF-1 complex remains relatively ineffective. Therefore, development of specific molecular targets is a key approach for identifying new cancer therapeutics. Thus, we attempted to synthesize a peptide (TAT-NLS-BLBD-6) that could interfere with the interaction of β-catenin and LEF-1 at nuclei in human breast cancer cells. TAT-NLS-BLBD-6 directly interacted with β-catenin and inhibited breast cancer cell growth, invasion, migration, and colony formation as well as increased arrest of sub-G1 phase and apoptosis; it also suppressed breast tumor growth in nude mouse and zebrafish xenotransplantation models, showed no signs of toxicity, and did not affect body weight. Furthermore, the human global gene expression profiles and Ingenuity Pathway Analysis software showed that the TAT-NLS-BLBD-6 downstream target genes were associated with the HER-2 and IL-9 signaling pathways. TAT-NLS-BLBD-6 commonly down-regulated 27 candidate genes in MCF-7 and MDA-MB-231 cells, which are concurrent with Wnt downstream target genes in human breast cancer. Our study suggests that TAT-NLS-BLBD-6 is a promising drug candidate for the development of effective therapeutics specific for Wnt/β-catenin signaling inhibition.

KRAS mutation coupled with p53 loss is sufficient to induce ovarian carcinosarcomas in mice

Ovarian carcinosarcoma cancer is the most lethal form of gynecological malignancy, but the pathogenesis and biological function for this ovarian cancer remain unknown. We establishment the transgenic mouse model of K‐rasG12Dp53loxP/loxP and found that K‐ras mutation and p53 deletion within the ovarian surface epithelium gave rise to ovarian lesions with a hyperproliferation and endometrioid glandular morphology. Furthermore, double mutant ovaries formed ovarian carcinosarcomas that were high grade and poorly differentiated. Induction was widely metastatic and spread to abdominal organs including liver, spleen, and kidney at 4 wk. We also confirmed the role of K‐rasG12D in ovarian cancer cell lines MCAS and PA‐1 and showed that K‐rasG12D overexpression strongly induced cell proliferation, migration, and invasion. The ovarian cancer model we developed recapitulates the specific tumor histomorphology and the probable mechanism of malignant transformation in endometriosis.