Expression Of Lysine-specific Demethylase Research Articles

Expression of lysine-specific demethylase 1 in hepatocellular carcinoma tissues and its effect on cell proliferation and invasion

Objective To investigate the expression of lysine-specific demethylase 1 (LSD1) in hepatocellular carcinoma tissues, and to explore the effects of down-regulation of LSD1 gene expression on proliferation and invasion of human hepatoma HepG2 cells. Methods A total of 91 cases of hepatocellular carcinoma undergoing elective surgery in our hospital and Henan Cancer Hospital were selected. Immunohistochemistry was used to detect the expression of LSD1 protein in hepatocellular carcinoma tissues and adjacent tissues. Human hepatoma HepG2 cells were cultured and divided into LSD1 interference sequence group, negative control group and blank group. Real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) was used to detect the expression of LSD1 gene in cells. Methyl thiazol tetrazolium (MTT) assay was used to detect cell proliferation. Transwell chamber was used to detect cell invasion. Western blotting was used to detect the expression of LSD1, Snail, E-cadherin and N-cadherin proteins in cells. Results The positive expression rate of LSD1 protein in hepatocellular carcinoma tissues was 81.32%, which was significantly higher than that in adjacent tissues (35.16%, P<0.01). The expression of LSD1 protein in hepatocellular carcinoma tissues was related to the degree of differentiation, TNM staging and vascular invasion (P<0.05). The relative expression level of LSD1 mRNA in LSD1 interference sequence group was 1.19±0.10, which was significantly lower than that in the negative control group and blank group (2.29±0.14 and 2.34±0.11, P<0.05). The absorbance (A) values at 24, 48, 72 and 96 h in the LSD1 interference sequence group were 0.23±0.05, 0.32±0.08, 0.38±0.08 and 0.52±0.03, respectively, which were significantly lower than those in the negative control group (0.38±0.08, 0.49±0.05, 0.67±0.04 and 0.77±0.10) and blank group (0.33±0.03, 0.52±0.09, 0.70±0.08 and 0.78±0.07, P<0.05). The number of invasive cells in the LSD1 interference sequence group was (86.3±3.9), which was significantly less than that in the negative control group (110.6±9.4) and the blank group (117.7±7.0, P<0.05). The relative expression levels of LSD1, Snail, and N-cadherin proteins in the LSD1 interference sequence group were (0.25±0.03, 0.30±0.02 and 0.32±0.03), which were significantly lower than those in the negative control group (0.77±0.06, 0.76±0.10 and 0.67±0.04) and blank group (0.84±0.14, 0.74±0.07 and 0.69±0.06, P<0.05), and the relative expression level of E-cadherin protein (0.71±0.05) was significantly higher than in the negative control group (0.37±0.02) and blank group (0.34±0.04, P<0.05). Conclusion LSD1 protein was highly expressed in hepatocellular carcinoma tissues, and might play an important role in the proliferation and invasion of human hepatoma HepG2 cells through epithelial-mesenchymal transition. Key words: Carcinoma, hepatocellular; Lysine-specific demethylase 1; Proliferation; Invasion; Epithelial-mesenchymal transition

Pharmacological inhibition of LSD1 activity blocks REST-dependent medulloblastoma cell migration

BackgroundMedulloblastoma (MB) is the most common malignant brain tumor in children. Current problems in the clinic include metastasis, recurrence, and treatment-related sequelae that highlight the need for targeted therapies. Epigenetic perturbations are an established hallmark of human MB and expression of Lysine Specific Demethylase 1 (LSD1) is elevated in MBs compared to normal tissue, suggesting that LSD1 inhibitors may have efficacy against human MB tumors.MethodsExpression of LSD1 was examined across a publicly-available database and correlated with patient outcomes. Sonic Hedgehog (SHH) MB samples were clustered based on expression of LSD1 and LSD1-associated RE-1 silencing transcription factor (REST) target genes as well as genes involved in metastasis. Resulting clusters were examined for patient outcomes associated with LSD1 and REST expression. Human SHH MB cell lines were transduced with a REST-transgene to create isogenic cell pairs. In vitro viability and cell migration assays were used to examine the effect of LSD1 knockdown or inhibition on these parameters.ResultsWe demonstrate that subsets of SHH MB tumors have elevated LSD1 expression coincident with increased expression of its deubiquitylase, USP7, and REST. Patients with co-elevation of USP7, REST, and LSD1 have poorer outcomes compared to those with lower expression of these genes. In SHH MB cell lines, REST elevation increased cell growth and LSD1 protein levels. Surprisingly, while genetic loss of LSD1 reduced cell viability, pharmacological targeting of its activity using LSD1 inhibitors did not affect cell viability. However, a reduction in REST-dependent cell migration was seen in wound healing, suggesting that REST-LSD1 interaction regulates cell migration. Ingenuity pathway analyses validated these findings and identified Hypoxia Inducible Factor 1 alpha (HIF1A) as a potential target. In line with this, ectopic expression of HIF1A rescued the loss of migration seen following LSD1 inhibition.ConclusionsA subset of SHH patients display increased levels of LSD1 and REST, which is associated with poor outcomes. REST elevation in MB in conjunction with elevated LSD1 promotes MB cell migration. LSD1 inhibition blocks REST-dependent cell migration of MB cells in a HIF1A-dependent manner.

Abstract PR02: Dynamic epigenetic regulation of glioblastoma tumorigenicity through a LSD1-MYC-OLIG2 axis

Abstract Glioblastoma is one of the most devastating of human cancers, with near-uniform fatality within two years of diagnosis. Therapeutic failure is thought to be related to small subpopulation of cells that exhibit the properties of self-renewal and tumorigenicity. Understanding how such subpopulations attain and retain these properties remains a central question in oncology. One fundamental issue is whether tumorigenicity exists within a static population of elite cells or whether the capacity is stochastically acquired. To test these models, we assayed the tumorigenicity of single-cell subclones derived from long-terms passaged and primary patient-derived xenograft (PDX) glioblastoma lines. Our findings were best described by a hybrid model that is largely deterministic (elite) but with opportunities for dynamic (stochastic) interchange between non-tumorigenic and tumorigenic states. To identify molecular determinants of tumorigenicity, we performed gene expression profiling of the subclones. Analysis of the data suggested that tumorigenicity in glioblastoma is a dynamic property driven by variation in MYC expression, which in turn regulates Olig2 expression, a neural stem cell marker. Ectopic expression of MYC conferred tumorigenicty and MYC silencing abolished tumorigenicity in vitro and in vivo for multiple PDX and GEMM models. Transition between tumorigenic and non-tumorigenic cell states was associated with changes in histone modification at the MYC locus mediated by expression of lysine-specific demethylase 1 (LSD1). The model suggests a critical LSD1-MYC-OLIG2 axis that regulates the dynamic transition between glioblastoma cell states of differing tumorigenicity and unveils a novel framework for glioblastoma therapeutic development. Citation Format: Clark Chen, David Kozono, Jie Li, Masayuki Nitta, Oltea Sampetrean, Kimberly Ng, David Gonda, Deepa S. Kushwaha, Dmitry Merzon, Valya Ramakrishnan, Shan Zhu, Kaya Zhu, Hiroko Matsui, Olivier Harismendy, Wei Hua, Ying Mao, Chang-Hyuk Kwon, Keith L. Ligon, Hideyuki Saya, Bob S. Carter, Donald P. Pizzo, Scott R. VandenBerg, Frank Furnari, Webster Cavenee. Dynamic epigenetic regulation of glioblastoma tumorigenicity through a LSD1-MYC-OLIG2 axis. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr PR02.

Expression of Lysine-specific demethylase 1 in human epithelial ovarian cancer.

BackgroundLysine-specific demethylase 1(LSD1) is implicated in the tumorigenesis and progression in various cancers. However, the expression of LSD1 in epithelial ovarian cancer and its clinical significance has not been examined in detail.MethodsImmunohistochemical was used to detect the expression of LSD1 in normal ovarian epithelial tissues, cystadenoma, borderline cystadenoma, and cystadenocarcinoma. Next, the correlations between expression of LSD1 and clinicopathological features was assessed in 96 species of serous cystadenocarcinoma and 36 species of mucinous cystadenocarcinoma.ResultsImmunohistochemical results showed that the expression of LSD1 was gradually increased from benign cystadenoma and borderline cystadenoma to cystadenocarcinoma. The positive ratio of LSD1 expression was 50% in normal ovarian epithelial tissues, 72% in serous cystadenoma, 73% in mucinous cystadenoma, 82% in borderline serous cystadenoma, 83% in borderline mucinous cystadenoma, 94% in serous cystadenocarcinoma and 92% in mucinous cystadenocarcinoma, respectively. LSD1 expression levels were associated with International Federation of Gynecology and Obstetrics stage and lymphatic metastasis in both serous and mucinous cystadenocarcinoma samples. Kaplan-Meier curves suggested that overall survival time of patients with high LSD1 expression was significantly shorter than that of patients with low LSD1 expression. Multivariate Cox proportional hazard regression indicated that higher LSD1 expression was a significant independent predictor of poor survival of EOC patients (P = 0.016).ConclusionsThese results suggest that LSD1 may be involved in carcinogenesis and progression with promising therapeutic potential for epithelial ovarian cancer.

Lysine-Specific Demethylase 1 (LSD1/KDM1A) Contributes to Colorectal Tumorigenesis via Activation of the Wnt/Β-Catenin Pathway by Down-Regulating Dickkopf-1 (DKK1)

We collected paired samples of tumor and adjacent normal colorectal tissues from 22 patients with colorectal carcinoma to compare the differences in the expression of lysine specific demethylase 1 (LSD1) in these two tissues. The results showed that in 19 paired samples (86.4%), LSD1 is more highly expressed in tumor tissue than in normal tissue. To explore the role of LSD1 in colorectal tumorigenesis, we used somatic cell gene targeting to generate an LSD1 knockout (KO) HCT 116 human colorectal cancer cell line as a research model. The analysis of phenotypic changes showed that LSD1 KO colorectal cancer cells are less tumorigenic, both in vivo and in vitro. The differential expression analysis of the cells by mRNA sequencing (RNA-Seq) yielded 2,663 differentially expressed genes, and 28 of these genes had highly significant differences (Q <0.01). We then selected the 4 colorectal cancer-related genes ADM, DKK1, HAS3 and SMURF2 for quantitative real-time PCR verification. The results showed that the differences in the expression of ADM, DKK1 and HAS3 were consistent with those measured using the RNA-Seq data. As DKK1 was the gene with the most significant differential expression, we analyzed the key proteins of the DKK1-related Wnt/β-catenin signaling pathway and found that, after knocking out LSD1, the amount of free β-catenin translocated to the nucleus was significantly reduced and that the transcription of the signaling pathway target gene c-Myc was down-regulated. Our studies show that LSD1 activates the Wnt/β-catenin signaling pathway by down-regulating the pathway antagonist DKK1, which may be one of the mechanisms leading to colorectal tumorigenesis.