Apolipoprotein C1 promotes prostate cancer cell proliferation in vitro

Here, we aimed to investigate the carcinogenic effects of apolipoprotein C1 (APOC1) in prostate cancer (PCa). APOC1 expression was evaluated in PCa and normal prostate specimens, and lentivirus‐mediated RNA interference was used to knockdown APOC1 in DU145 cells. The effects of APOC1 silencing on cell proliferation, cell cycle arrest, and apoptosis were assessed. APOC1 expression was much higher in PCa tissues than in normal tissues. Moreover, APOC1 silencing inhibited cell proliferation and colony formation, arrested cell cycle progression, and enhanced apoptosis in DU145 cells. Additionally, APOC1 silencing decreased survivin, phospho‐Rb, and p21 levels and increased cleaved caspase‐3 expression. These data supported the procarcinogenic effects of APOC1 in the pathogenesis of PCa and suggested that targeting APOC1 may have applications in the treatment of PCa.     

Notch1 regulates tongue cancer cells proliferation,apoptosis and invasion

Objectives: Notch1 regulates tumor biology in a complex, context-dependent manner. The roles of Notch1 in tongue cancer are still controversial. The aim of this study is to investigate the roles of Notch1 in tongue cancer.

Materials and Methods: The expression of Notch1 was tested between tongue cancer and normal samples by using immunohistochemistry. Tongue cancer cells were transfected with siRNA or plasmid, respectively. Cell proliferation, apoptosis, migration and invasion ability were tested in appropriate ways. The subcutaneous tumor model was established to observe the tumor growth.

Results: Notch1 was upregulated in tongue carcinoma tissues and the expression of Notch1 was related with tumor stage and differentiation. Overexpression of Notch1 could increase tongue cancer cells proliferation, invasion and migration. But inhibited the expression of Notch1 could decrease cells proliferation, invasion and migration and promote cell apoptosis in vitro and in vivo.

Conclusion: Our results prove that the oncogenic role of Notch1 in tongue cancer and provide the direction of targeted therapy of tongue cancer.     

MicroRNA-384 regulates cell proliferation and apoptosis through directly targeting WISP1 in laryngeal cancer

Laryngeal cancer (LC) is an increasingly common malignant tumors of head and neck cancer. Aberrant expression of microRNA (miRNA) is closely related with LC development. In the current study, we investigated the biological function and underlying molecular mechanism of miR-384 in LC. The results showed that the miR-384 expression was markedly downregulated in LC tissue and cell lines (TU212 and TU686) as compared with that of adjacent nontumor tissues and a normal human bronchial epithelial cell line. Next, we performed gain-of-function and loss-of-function experiments in the TU212 and TU686 cells by transfecting the cells with miR-384 mimics, miR-384 inhibitor, or miRNA control. Moreover, results showed that miR-384 mimic remarkably inhibited LC cell proliferation, which was notably decreased by miR-384 inhibitor. Furthermore, miR-384 mimics notably increased the amounts of DNA fragmentation from the apoptotic cells (a hallmark of apoptosis) and the caspase-3 activity, whereas miR-384 inhibitor resulted in a decline of DNA fragmentation and the caspase-3 activity compared with its control. In addition, a dual-luciferase reporter assay confirmed that Wnt-induced secreted protein-1 (WISP1) gene was a direct target of miR-384. MiR-384 mimic remarkably inhibited the messenger RNA and protein expression of WISP1, which was upregulated by miR-384 inhibitor as compared to its control. WISP1 knockdown by small interfering RNA inhibited LC cell proliferation and promoted cell apoptosis. WISP1 overexpression partly abrogates the effect of miR-384 overexpression. Taken together, these data indicate that miR-384 regulates LC cell proliferation and apoptosis through targeting WISP1 signaling pathway, providing a novel insight into the LC treatment.     

C1qTNF-related protein-6 mediates fatty acid oxidation via the activation of the AMP-activated protein kinase

C1qTNF-related proteins (CTRPs) are involved in diverse processes including metabolism, inflammation host defense, apoptosis, cell differentiation, autoimmunity, hibernation, and organogenesis. However, the physiological role of CTRP6 remains poorly understood. Here we demonstrate that the globular domain of CTRP6 mediates the phosphorylation and activation of the 5′-AMP-activated protein kinase (AMPK) in skeletal muscle cells. In parallel with the activation of AMPK, CTRP6 induces the phosphorylation of acetyl coenzyme A carboxylase (ACC) and fatty acid oxidation in myocytes. Thus, CTRP6 plays a role in fatty acid metabolism via the AMPK-ACC pathway.     

胡椒碱对白纹伊蚊C6/36细胞株的毒性作用

采用MTT检测法、Annexin-V/PI双染流式细胞仪检测法及细胞形态学观察法,研究了植物型杀虫剂胡椒碱对白纹伊蚊Aedes albopictus C6/36细胞株的细胞毒性、诱导细胞凋亡与坏死的关系、Fas蛋白的表达、细胞生长状态改变及受损细胞的恢复。结果表明：胡椒碱浓度在0.035 mmol/L以上时可以诱发C6/36细胞形态学改变,在倒置显微镜下表现为细胞呈多形性,细胞胀大或皱缩,细胞间隙增宽,大片细胞聚集成团,脱落、崩解、死亡。用胡椒碱处理24 h后,对C6/36细胞的半数毒性浓度（IC₅₀）为 0.32 mmol/L,且毒性作用强度随着药物浓度增加而增强。Annexin-V/PI双染法检测结果显示药物浓度在0.28 mmol/L 以上诱导的细胞凋亡明显,药物浓度为0.56 mmol/L 时细胞凋亡率达19.4%,而药物引起的细胞总死亡率为72.7%;Fas蛋白表达在药物浓度0.28 mmol/L 以上时有所上调,但不明显。高浓度胡椒碱（0.56 mmol/L）分别作用于C6/36细胞24和48 h,在经历一段生长停滞后,24 h组受损细胞均可缓慢恢复,而48 h组细胞则出现不可逆性的损伤。由此认为：胡椒碱对C6/36细胞株有毒性作用,但药物诱导的细胞凋亡在细胞毒性作用机制中不占主导地位;胡椒碱对C6/36细胞的作用有时间依赖性,延长作用时间,药物对细胞的毒性作用增强。     

LncRNA PWAR6 regulates proliferation and migration by epigenetically silencing YAP1 in tumorigenesis of pancreatic ductal adenocarcinoma

Long non-coding RNAs (lncRNAs) are a novel class of regulators in multiple cancer biological processes. However, the functions of lncRNAs in pancreatic ductal adenocarcinoma (PDAC) remain largely unknown. In this study, we identified PWAR6 as a frequently down-regulated lncRNA in PDAC samples as well as a panel of pancreatic cancer cell lines. Down-regulated PWAR6 was associated with multiple clinical outcomes, including advanced tumour stage, distant metastasis, and overall survival of PDAC patients. In our cell-based assays, ectopic expression of PWAR6 dramatically repressed PDAC cells proliferation, invasion and migration, accelerated apoptosis, and induced cell cycle arrest at G0/G1 phase. In contrast, depletion of PWAR6 mediated by siRNA exhibited opposite effects on PDAC cell behaviours. In vivo study further validated the anti-tumour role of PWAR6 in PDAC. By taking advantage of available online sources, we also identified YAP1 as a potential PWAR6 target gene. Negative correlation between YAP1 and PWAR6 expressions were observed in both online database and our PDAC samples. Notably, rescue experiments further indicated that YAP1 is an important downstream effector involved in PWAR6-mediated functions. Mechanistically, PWAR6 could bind to methyltransferase EZH2, a core component of Polycomb Repressive Complex 2 (PRC2) in regulating gene expression, and scaffold EZH2 to the promoter region of YAP1, resulting in epigenetic repression of YAP1. In conclusion, our data manifest the vital roles of PWAR6 in PDAC tumorigenesis and underscore the potential of PWAR6 as a promising target for PDAC diagnosis and therapy.     

cIAP1/2 are involved in the radiosensitizing effect of birinapant on NSCLC cell line in vitro

Tumour radioresistance is a major problem for cancer radiation therapy. To identify the underlying mechanisms of this resistance, we used human non-small cell lung cancer (NSCLC) cell lines and focused on the Inhibitor of Apoptosis Protein (IAP) family, which contributes to tumourigenesis and chemoresistance. We investigated the possible correlation between radioresistance in six NSCLC cell lines and IAP protein levels and tested the radiosensitizing effect of birinapant in vitro, a molecule that mimics the second mitochondria-derived activator of caspase. We found that birinapant-induced apoptosis and inhibited the proliferation of NSCLC cells after exposure to radiation. These effects were induced by birinapant downregulation of cIAP protein levels and changes of cIAP gene expression. Overall, birinapant can inhibit tumour growth of NSCLC cell lines to ironizing radiation and act as a promising strategy to overcome radioresistance in NSCLC.     

MiR-543 regulates myoblast proliferation and differentiation of C2C12 cells by targeting KLF6

MicroRNA-543 (miR-543) has been found to play a suppressive role in various human cancers in many studies, whereas the specific functions of miR-543 in muscle development remain poorly understood. Here, we found that the expression of miR-543 was high in skeletal muscle and increased during the differentiation of C2C12 cells. Overexpression of miR-543 repressed C2C12 cell proliferation and promoted differentiation, while knockdown of miR-543 expression produced the opposite results. During myogenesis, we predicted and verified that Krüppel-like factor 6 (KLF6), a suppressor of multiple tumor cells, was a target gene of miR-543. Then, miR-543 was found to specifically target KLF6 and repress its expression. Besides this, knockdown of KLF6 promoted the differentiation but inhibited the proliferation of C2C12 cells. Si-KLF6 can rescue the influence of miR-543 inhibitor on C2C12 cell differentiation. Our results indicate a new regulatory mechanism of miR-543 on KLF6 expression and suggest the possibility of using the miR-543/KLF6 pathway as a potential target for studying myogenesis.     

Fluid shear stress regulates osteoblast proliferation and apoptosis via the lncRNA TUG1/miR-34a/FGFR1 axis

LncRNAs and microRNAs play critical roles in osteoblast differentiation and bone formation. However, their exact roles in osteoblasts under fluid shear stress (FSS) and the possible mechanisms remain unclear. The aim of this study was to explore whether and how miR-34a regulates osteoblast proliferation and apoptosis under FSS. In this study, FSS down-regulated miR-34a levels of MC3T3-E1 cells. MiR-34a up-regulation attenuated FSS-induced promotion of proliferation and suppression of apoptosis. Luciferase reporter assay revealed that miR-34a directly targeted FGFR1. Moreover, miR-34a regulated osteoblast proliferation and apoptosis via FGFR1. Further, we validated that lncRNA TUG1 acted as a competing endogenous RNA (ceRNA) to interact with miR-34a and up-regulate FGFR1 protein expression. Furthermore, lncRNA TUG1 could promote proliferation and inhibit apoptosis. Taken together, our study revealed the key role of the lncRNA TUG1/miR-34a/FGFR1 axis in FSS-regulated osteoblast proliferation and apoptosis and may provide potential therapeutic targets for osteoporosis.     

Knockdown of LncRNAZFAS1 suppresses cell proliferation and metastasis in non-small cell lung cancer

ABSTRACT

To evaluate the effects of LncRNAZFAS1 on cell proliferation and tumor metastasis in non-small cell lung cancer (NSCLC), we detected the expression level of LncRNAZFAS1 in NSCLC-related tissues and cells. qRT-PCR results revealed that LncRNAZFAS1 in tumor tissues was significantly higher than that in normal lung tissue, especially significantly up-regulated in stage III / IV and in metastatic NSCLC tissues. LncRNAZFAS1 expression was dramatically up-regulated in 4 NSCLC-related cells (A549, SPC-A1, SK-MES-1, and NCI-H1299), with having the highest expression level in A549 cells. Furthermore, we implemented a knockdown of LncRNAZFAS1 in A549 cells, and the results of CCK8 and Transwell assays suggested that knockdown of LncRNAZFAS1 significantly inhibited NSCLC cell proliferation and metastasis. Next, we constructed a tumor xenograft model to evaluate the effect of LncRNAZFAS1 on the NSCLC cell proliferation in vivo. The results indicated that knockdown of LncRNAZFAS1 dramatically inhibited A549 cells proliferation and repressed tumor growth. Additionally, knockdown of LncRNAZFAS1 drastically weakened the expressions of MMP2, MMP9 and Bcl-2 proteins, whereas noticeably strengthened the expression of BAX protein. Our results altogether suggest that knockdown of LncRNAZFAS1 has a negative effect on the proliferation and metastasis of NSCLC cell, which implying LncRNAZFAS1 is a potential unfavorable biomarker in patients with NSCLC.     

CKIP-1 regulates macrophage proliferation by inhibiting TRAF6-mediated Akt activation

Macrophages play pivotal roles in development, homeostasis, tissue repair and immunity. Macrophage proliferation is promoted by macrophage colony-stimulating factor (M-CSF)-induced Akt signaling; yet, how this process is terminated remains unclear. Here, we identify casein kinase 2-interacting protein-1 (CKIP-1) as a novel inhibitor of macrophage proliferation. In resting macrophages, CKIP-1 was phosphorylated at Serine 342 by constitutively active GSK3β, the downstream target of Akt. This phosphorylation triggers the polyubiquitination and proteasomal degradation of CKIP-1. Upon M-CSF stimulation, Akt is activated by CSF-1R-PI3K and then inactivates GSK3β, leading to the stabilization of CKIP-1 and β-catenin proteins. β-catenin promotes the expression of proliferation genes including cyclin D and c-Myc. CKIP-1 interacts with TRAF6, a ubiquitin ligase required for K63-linked ubiquitination and plasma membrane recruitment of Akt, and terminates TRAF6-mediated Akt activation. By this means, CKIP-1 inhibits macrophage proliferation specifically at the late stage after M-CSF stimulation. Furthermore, CKIP-1 deficiency results in increased proliferation and decreased apoptosis of macrophages in vitro and CKIP-1^−/− mice spontaneously develop a macrophage-dominated splenomegaly and myeloproliferation. Together, these data demonstrate that CKIP-1 plays a critical role in the regulation of macrophage homeostasis by inhibiting TRAF6-mediated Akt activation.     

MiR‐34b‐3p represses cell proliferation,cell cycle progression and cell apoptosis in non‐small‐cell lung cancer (NSCLC) by targeting CDK4

Lung cancer is the most common incident cancer, with a high mortality worldwide, and non‐small‐cell lung cancer (NSCLC) accounts for approximately 85% of cases. Numerous studies have shown that the aberrant expression of microRNAs (miRNAs) is associated with the development and progression of cancers. However, the clinical significance and biological roles of most miRNAs in NSCLC remain elusive. In this study, we identified a novel miRNA, miR‐34b‐3p, that suppressed NSCLC cell growth and investigated the underlying mechanism. miR‐34b‐3p was down‐regulated in both NSCLC tumour tissues and lung cancer cell lines (H1299 and A549). The overexpression of miR‐34b‐3p suppressed lung cancer cell (H1299 and A549) growth, including proliferation inhibition, cell cycle arrest and increased apoptosis. Furthermore, luciferase reporter assays confirmed that miR‐34b‐3p could bind to the cyclin‐dependent kinase 4 (CDK4) mRNA 3′‐untranslated region (3′‐UTR) to suppress the expression of CDK4 in NSCLC cells. H1299 and A549 cell proliferation inhibition is mediated by cell cycle arrest and apoptosis with CDK4 interference. Moreover, CDK4 overexpression effectively reversed miR‐34‐3p‐repressed NSCLC cell growth. In conclusion, our findings reveal that miR‐34b‐3p might function as a tumour suppressor in NSCLC by targeting CDK4 and that miR‐34b‐3p may, therefore, serve as a biomarker for the diagnosis and treatment of NSCLC.