Poly (ADP) ribose polymerase inhibition: A potential treatment of malignant peripheral nerve sheath tumor

Poly (ADP) ribose polymerase (PARP) inhibitors, first evaluated nearly a decade ago, are primarily used in malignancies with known defects in DNA repair genes, such as alterations in breast cancer, early onset 1/2 (BRCA1/2). While no specific mutations in BRCA1/2 have been reported in malignant peripheral nerve sheath tumors (MPNSTs), MPNST cells could be effectively targeted with a PARP inhibitor to drive cells to synthetic lethality due to their complex karyotype and high level of inherent genomic instability. In this study, we assessed the expression levels of PARP1 and PARP2 in MPNST patient tumor samples and correlated these findings with overall survival. We also determined the level of PARP activity in MPNST cell lines. In addition, we evaluated the efficacy of the PARP inhibitor AZD2281 (Olaparib) in MPNST cell lines. We observed decreased MPNST cell proliferation and enhanced apoptosis in vitro at doses similar to, or less than, the doses used in cell lines with established defective DNA repair genes. Furthermore, AZD2281 significantly reduced local growth of MPNST xenografts, decreased the development of macroscopic lung metastases, and increased survival of mice with metastatic disease. Our results suggest that AZD2281 could be an effective therapeutic option in MPNST and should be further investigated for its potential clinical use in this malignancy.     

连翘苷通过激活Hippo-YAP信号通路抑制结肠癌LS180细胞的恶性生 物学行为

目的：探究连翘苷（Phi）通过调控Hippo/YAP信号通路对结肠癌LS180细胞增殖、迁移和侵袭的影响。方法：用不同浓度（0、5、10、20、40、80 μmol/L）的Phi处理人结肠癌LS180细胞,MTT法检测24、48 和72 h时的细胞活力。将LS180细胞分为对照组、Phi-L（5 μmol/L Phi）组、Phi-M（10 μmol/L Phi）组、Phi-H（20 μmol/L Phi）组、Phi-H+YAP抑制剂维替泊芬（VP）组（20 μmol/L Phi+5 μmol/L VP）,各组均处理24 h。EdU法检测Phi对各组细胞增殖的影响,划痕愈合实验、Transwell小室法分别检测Phi对细胞迁移和侵袭的影响,免疫荧光法和WB 法检测 Phi 对细胞 Ki-67 表达率和LATS1、YAP和p-YAP、MMP-2、MMP-9、E-cadherin、N-cadherin表达的影响。构建LS180细胞移植瘤裸鼠模型,观察Phi对移植瘤体积和质量的影响,免疫荧光法和WB法检测移植瘤组织中Ki-67表达率和LATS1、YAP和p-YAP蛋白的表达水平。结果：与对照组比较,Phi-L、Phi-M和Phi-H组LS180细胞EdU阳性率、划痕愈合率、侵袭细胞数、Ki-67阳性率、MMP-2、MMP-9、N-cadherin表达均显著降低（均P<0.05）,E-cadherin、LATS1和p-YAP/YAP表达均显著升高（均P<0.05）;同时使用VP则部分逆转了Phi对LS180细胞增殖、迁移与侵袭的抑制作用（均 P<0.05）Phi显著抑制裸鼠移植瘤生长,与对照组比较,Phi组裸鼠移植瘤体积、质量和 Ki-67 阳性率均显著降低（均 P<0.05）,LATS1和 p-YAP/YAP 水平均显著升高（均P<0.05）。结论：Phi可能通过激活Hippo/YAP信号通路抑制结肠癌LS180细胞的恶性生物学行为。     

虎杖苷通过Hippo/YAP通路影响甲状腺癌8505C细胞的恶性生物学行为和顺铂敏感性

目的：探究虎杖苷通过Hippo/Yes相关蛋白（YAP）通路对人甲状腺癌8505C细胞的恶性生物学行为和顺铂（DDP）敏感性的影响。方法：体外培养8505C细胞,构建其DDP耐药细胞8505C/DDP,用CCK-8法检测0、25、50、75、100 nmol/L虎杖苷处理8505C和8505C/DDP细胞的增殖能力,以筛选虎杖苷的最佳作用浓度。将8505C细胞分为对照组、虎杖苷组、空载组、虎杖苷+YAP1过表达组;将8505C/DDP细胞分为对照组、DDP组、DDP+虎杖苷组、DDP+空载组、DDP+虎杖苷+YAP1过表达组。WB法检测各组8505C细胞中Hippo/YAP通路[YAP1、转录辅激活因子（TAZ）]和EMT(E-cadherin、N-cadherin)相关蛋白,8505C/DDP细胞中YAP1、TAZ、耐药相关蛋白[P-糖蛋白（P-gp）、多药耐药相关蛋白1(MRP1)]、凋亡相关蛋白（C-caspase-3、BAX、Bcl-2）的表达。Transwell小室和细胞划痕实验分别检测各组8505C、8505C/DDP细胞的侵袭、迁移能力。结果：虎杖苷可显著抑制8505C细...     

Antitumor effects of 4‐methylumbelliferone,a hyaluronan synthesis inhibitor,on malignant peripheral nerve sheath tumor

Hyaluronan (HA) has been shown to play important roles in the growth, invasion and metastasis of malignant tumors. Our previous study showing that high HA expression in malignant peripheral nerve sheath tumors (MPNST) is predictive of poor patient prognosis, prompted us to speculate that inhibition of HA synthesis in MPNST might suppress the tumorigenicity. The aim of our study was to investigate the antitumor effects of 4‐methylumbelliferone (MU), an HA synthesis inhibitor, on human MPNST cells and tissues. The effects of MU on HA accumulation and tumorigenicity in MPNST cells were analyzed in the presence or absence of MU in an in vitro as well as in vivo xenograft model using human MPNST cell lines, sNF96.2 (primary recurrent) and sNF02.2 (metastatic). MU significantly inhibited cell proliferation, migration and invasion in both MPNST cell lines. HA binding protein (HABP) staining, particle exclusion assay and quantification of HA revealed that MU significantly decreased HA accumulation in the cytoplasms and pericellular matrices in both MPNST cell lines. The expression levels of HA synthase2 (HAS2) and HA synthase3 (HAS3) mRNA were downregulated after treatment with MU. MU induced apoptosis of sNF96.2 cells, but not sNF02.2 cells. MU administration significantly inhibited the tumor growth of sNF96.2 cells in the mouse xenograft model. To the best of our knowledge, our study demonstrates for the first time the antitumor effects of MU on human MPNST mediated by inhibition of HA synthesis. Our results suggest that MU may be a promising agent with novel antitumor mechanisms for MPNST.     

LPIN1 downregulation enhances anticancer activity of the novel HDAC/PI3K dual inhibitor FK‐A11

Phosphatidylinositol‐3 kinase (PI3K) inhibitor and histone deacetylase (HDAC) inhibitor have been developed as potential anticancer drugs. However, the cytotoxicity of PI3K inhibitor or HDAC inhibitor alone is relatively weak. We recently developed a novel HDAC/PI3K dual inhibitor FK‐A11 and confirmed its enhanced cytotoxicity when compared to that of PI3K inhibitor or HDAC inhibitor alone on several cancer cell lines. However, the in vivo antitumor activity of FK‐A11 was insufficient. We conducted high‐throughput RNA interfering screening and identified gene LPIN1 which enhances the cytotoxicity of FK‐A11. Downregulation of LPIN1 enhanced simultaneous inhibition of HDAC and PI3K by FK‐A11 and enhanced the cytotoxicity of FK‐A11. Propranolol, a beta‐adrenoreceptor which is also a LPIN1 inhibitor, enhanced the in vitro and in vivo cytotoxicity and antitumor effect of FK‐A11. These findings should help in the development of FK‐A11 as a novel HDAC/PI3K dual inhibitor.