抑制LSD1酶活性对HBV模型小鼠的作用

目的研究组蛋白赖氨酸去甲基化酶1（LSDl）酶活性下降对乙型肝炎病毒（HBV）模型小鼠的作用。方法尾静脉高压注射重组HBVl．3质粒建立HBV小鼠模型;将雌性BALB／c小鼠随机分为正常组、模型组、LSDl小干扰RNA（siRNA）处理组和反苯环丙胺（TCP）治疗组。取各组小鼠外周血,通过酶联免疫吸附试验、全自动微粒子化学发光法和Real—TimePCR检测小鼠体内乙肝表面抗原（hepatitis B surface antigen,HBsAg）和HBVDNA的表达;免疫组织化学法检测HBsAg在肝脏中的分布;Western blotting检测小鼠脾淋巴细胞LSDl的表达。结果HBV模型小鼠造模成功;LSDlsiRNA处理组和TCP治疗组小鼠HBsAg、HBVDNA和LSDl的表达水平均较模型组明显下降（P〈0．01）,肝组织中HBsAg的分布也明显减少。结论抑制LSDl酶活性对HBV模型小鼠体内HBV的清除有一定的作用。     

Discovery of [1,2,3]triazolo[4,5-d]pyrimidine derivatives as highly potent,selective, and cellularly active USP28 inhibitors

Ubiquitin specific peptidase 28 (USP28) is closely associated to the occurrence and development of various malignancies, and thus has been validated as a promising therapeutic target for cancer therapy. To date, only few USP28 inhibitors with moderate inhibitory activity have been reported, highly potent and selective USP28 inhibitors with new chemotypes remain to be discovered for pathologically investigating the roles of deubiquitinase. In this current study, we reported the synthesis and biological evaluation of new [1,2,3]triazolo[4,5-d]pyrimidine derivatives as potent USP28 inhibitors. Especially, compound 19 potently inhibited USP28 (IC₅₀ = 1.10 ± 0.02 μmol/L, K_d = 40 nmol/L), showing selectivity over USP7 and LSD1 (IC₅₀ > 100 μmol/L). Compound 19 was cellularly engaged to USP28 in gastric cancer cells. Compound 19 reversibly bound to USP28 and directly affected its protein levels, thus inhibiting the proliferation, cell cycle at S phase, and epithelial-mesenchymal transition (EMT) progression in gastric cancer cell lines. Docking studies were performed to rationalize the potency of compound 19. Collectively, compound 19 could serve as a new tool compound for the development of new USP28 inhibitors for exploring the roles of deubiquitinase in cancers.     

Knockdown of KDM1B inhibits cell proliferation and induces apoptosis of pancreatic cancer cells

Pancreatic cancer (PC) is one of the common malignant tumors in digestive tract with a high fatality rate. The oncogenic role of lysine-specific demethylase1 (LSD1/KDM1?A) has been well recognized in PC. While, the role of its homolog LSD2 (KDM1B) in regulating PC progression is poorly understood. In this study, we attempted to evaluate the functional role of KDM1B in PC cells. The expression of KDM1B was detected by immunohistochemistry and immunoblotting in PC tissues and cells. Lentivirus-mediated shRNA was applied to silence KDM1B in PANC-1 and SW1990 cells. Cell proliferation was measured by MTT and Celigo assay. Cell apoptosis was determined by both Caspase-Glo^®3/7 assay and Flow cytometry. Intracellular signaling molecules were detected using a PathScan intracellular signaling array kit. In this study, we found KDM1B was highly expressed in PC tissues compared to paracancerous tissues. Moreover, elevated expression of KDM1B was detected in PC cell lines (BxPC-3, CFPAC-1, PANC-1 and SW1990) as compared with a normal human pancreatic duct epithelial cell line (HPDE6-C7). Further investigations revealed that KDM1B knockdown significantly inhibited PC cell proliferation. Furthermore, the apoptosis of PANC-1 and SW1990 cells was significantly increased after KDM1B knockdown. Notably, the activations of p-ERK1/2, p-Smad2, p-p53, cleaved PARP, cleaved Caspase-3, cleaved Caspase-7, p-eIF2a and Survivin were promoted by KDM1B knockdown, while IkBa was suppressed. Taken together, our findings provided new insights into the critical and multifaceted roles of KDM1B in the regulation of cell proliferation and apoptosis, and offered a potentially novel target in preventing the progression of PC.     

Lysine‐specific demethylase‐1 contributes to malignant behavior by regulation of invasive activity and metabolic shift in esophageal cancer

Lysine‐specific demethylase‐1 (LSD1) removes the methyl groups from mono‐ and di‐methylated lysine 4 of histone H3. Previous studies have linked LSD1 to malignancy in several human tumors, and LSD1 is considered to epigenetically regulate the energy metabolism genes in adipocytes and hepatocellular carcinoma. This study investigates the function of LSD1 in the invasive activity and the metabolism of esophageal cancer cells. We investigated whether LSD1 immunohistochemical expression levels are related to clinical and pathological features, including the maximum standard uptake value in fluorodeoxyglucose positron emission tomography assay. The influence of LSD1 on cell proliferation, invasion and glucose uptake was evaluated in vitro by using specific small interfering RNA for LSD1, and an LSD1 inhibitor. We also evaluated two major energy pathways (glycolytic pathway and mitochondrial respiration) by measuring the extracellular acidification rate (ECAR) and the oxygen consumption rate (OCR) with an extracellular flux analyzer. High LSD1 immunohistochemical expression was significantly associated with high tumor stage, lymphovascular invasion, poor prognosis, and high maximum standard uptake value in esophageal cancer patients. In the in vitro analysis, LSD1 knockdown significantly suppressed the invasive activity and glucose uptake of cancerous cells, reduced their ECAR and increased their OCR and OCR/ECAR. LSD1 may contribute to malignant behavior by regulating the invasive activity and metabolism, activating the glycolytic pathway and inhibiting the mitochondrial respiration of esophageal cancer cells. The results support LSD1 as a potential therapeutic target.     

Inhibitors of LSD1 as a potential therapy for acute myeloid leukemia

Introduction: Epigenetic dysregulation plays a critical role in the pathogenesis of acute myeloid leukemia (AML). Alterations in histone methylation lead to aberrant silencing of expression of multiple genes involved in tumor suppression and cell cycling, resulting in myeloid maturation arrest and proliferation of early myeloid progenitors. One promising approach targeting chromatin regulatory proteins is inhibition of lysine specific demethylase-1 (LSD1), an enzyme responsible for demethylation of histone H3 as well as other functions

Areas covered: Available literature on LSD1 in normal and malignant hematopoiesis was identified in PubMed and reviewed. Areas addressed here include the biology of LSD1, pharmacologic inhibitors, and preclinical data supporting the rationale for LSD1 inhibition in AML therapy.

Expert opinion: LSD1 inhibitors represent a promising novel epigenetic approach for AML therapy. Preclinical studies have revealed that pharmacologic LD1 inhibitors function primarily by altering stem cell programs and restoring myeloid differentiation to AML cells. These effects are markedly enhanced in combination with trans-retinoic acid or histone deacetylase inhibitors with little toxicity. Currently, multiple oral LSD1 inhibitors are undergoing phase 1 investigation in patients with AML. The results of these clinical trials are eagerly awaited.