Up-regulation of cyclinD1 and Bcl2A1 by insulin is involved in osteoclast proliferation

Aims

Insulin receptor signaling in osteoblasts has been well established, but the effects of insulin on osteoclast proliferation are poorly explored. The objective of this study was to investigate the roles and the mechanisms of insulin on osteoclast proliferation.

Main methods

After insulin treatment to primary osteoclast precursors, BrdU incorporation assay was performed and the expression of cell cycle- and apoptosis-related genes was determined by real-time PCR and immunoblotting. Apoptosis was analyzed using a FACScan flow cytometer.

Key findings

Insulin activated insulin receptor and promoted the proliferation of osteoclast precursors in time- and dose-dependent manners. However, the expression of insulin receptor was not changed by it during that time. Insulin remarkably induced the expression of cyclinD1, a cell cycle marker, and Bcl2A1, an anti-apoptotic oncogene, whereas cdk1 and cdk4 were not affected by it. The expression of Bcl2l11 and Bax, both apoptotic markers, was reduced or not changed in osteoclast precursors. Bcl2A1/Bax ratio was also increased in protein levels. Treatment with obatoclax, a Bcl2 family inhibitor, significantly induced the apoptosis of osteoclast precursors in the presence of insulin. These results demonstrate that insulin promotes osteoclast proliferation by increasing cell cycle and suppressing apoptosis through specific gene regulation.

Significance

These data provide a basis for understanding and ultimately treating several bone-related metabolic diseases.     

Up-regulation of MELK by E2F1 promotes the proliferation in cervical cancer cells

Cervical cancer is a common gynecologic cancer and a frequent cause of death. In this study, we investigated the role of MELK (maternal embryonic leucine zipper kinase) in cervical cancer. We found that HPV 18 E6/E7 promoted MELK expression by activating E2F1. MELK knockdown blocked cancer cells growth. Furthermore, we used MELK-8A to inhibit the kinase activity of MELK and caused the G2/M phase arrest of cancer cells. Under the treatment of inhibitors, Hela cells formed multipolar spindles and eventually underwent apoptosis. We also found that MELK is involved in protein translation and folding during cell division through the MELK interactome and the temporal proteomic analysis under inhibition with MELK-8A. Altogether, these results suggest that MELK may play a vital role in cancer cell proliferation and indicate a potential therapeutic target for cervical cancer.     

Anosmin-1 involved in neuronal cell migration is hypoxia inducible and cancer regulated

Functional expression of KAL1 gene is critical in the migration of GnRH neurons from the olfactory placode to the hypothalamus in embryogenesis. This gene thus far has not been shown to play a functional role in any other physiological or pathological process either in the developed brain or in peripheral tissues. We show here that KAL1 gene expression is decreased in early stage and increased in later stages of cancers. Screening of colon, lung and ovarian cancer cDNA panels indicated significant decrease in KAL1 expression in comparison to corresponding uninvolved tissues. However, KAL1 expression increased with the progression of cancer from early (I and II) stages to later (III and IV) stages of the cancer. There was a direct correlation between the TGF-β and KAL1 expression in colon cancer cDNA. Using colon cancer cell lines, we showed that TGF-β induces KAL1 gene expression and secretion of anosmin-1 protein (KAL1 coded protein). We further report that hypoxia induces anosmin-1 expression; anosmin-1 protects cancer cells from apoptosis activated by hypoxia and increases cancer cell mobility. Using siRNA technique we found that KAL1 expression following hypoxia is hypoxia-inducible factor (HIF-1) α dependent. Our results suggest that KAL1 gene expression plays an important role in cancer metastasis and protection from apoptosis.     

周期蛋白D1参与香烟烟雾提取物促进人肺动脉平滑肌细胞增殖和迁移

本文旨在探讨周期蛋白D1(cyclin D1)在香烟烟雾提取物(cigarette smoke extract,CSE)所致人肺动脉平滑肌细胞(human pulmonary artery smooth muscle cells,HPASMCs)增殖和迁移中的作用。构建反义cyclin D1基因真核表达载体(pIRES2-EGFP-ascyclin D1),采用脂质体介导基因转染法将空载体(pIRES2-EGFP)和pIRES2-EGFP-ascyclin D1导入正常HPASMCs后,分别进行CSE干预。细胞随机分为6组:对照组、空载体组、反义cyclin D1组、5%CSE组、空载体+5%CSE组、反义cyclin D1+5%CSE组。用实时荧光RT-PCR和Western blot法分别检测cyclin D1mRNA和蛋白的表达,采用流式细胞术、四甲基偶氮唑盐比色法(MTT)、增殖细胞核抗原(PCNA)染色法测定细胞增殖能力,Transwell小室法检测细胞迁移能力。结果显示,反义cyclin D1基因真核表达载体pIRES2-EGFP-ascyclin D1成功构建,并成功转染入HPASMCs,转染后HPASMCs中cyclin D1的mRNA和蛋白表达水平较对照组均显著下降(P0.05)。与对照组比较,5%CSE组cyclinD1的mRNA和蛋白表达水平均明显升高(P0.05),细胞增殖和迁移能力显著增强(P0.05)。与5%CSE组比较,反义cyclinD1+5%CSE组cyclin D1mRNA和蛋白表达水平均明显下降(P0.05),细胞增殖和迁移能力显著降低(P0.05)。上述结果提示,CSE可通过上调cyclin D1表达促进HPASMCs增殖和迁移,反义cyclin D1基因真核表达载体可抑制CSE介导的HPASMCs增殖和迁移,提示cyclin D1在CSE所致HPASMCs增殖和迁移中发挥重要调控作用。     

Kidney injury molecule-1 is involved in the chemotactic migration of mesenchymal stem cells

A better understanding of the organ specific factors that regulate the migration of mesenchymal stem cells (MSCs) into the target organ is essential for optimization of strategies to improve the repair after injury. In the present study, we showed that the kidney injury molecule-1 (KIM-1), a well-known kidney-specific biomarker, enhanced the in vitro migration capacity of MSCs as a potent kidney-specific chemo-attractant or an inducer. The in vitro roles were verified by migration assay using KIM1-PK1 cell lines, the mouse proximal tubular epithelial cells (mPTEs) and recombinant human KIM-1 proteins (rhKIM-1). Immunofluorescence staining displayed specific ectodomain binding of KIM-1 on the surface of MSCs. Upregulation of chemokine receptor type 4 (CXCR4) protein when treated with tumor necrosis factor alpha (TNF-α) was shown. The effect of KIM-1 on migration of MSCs was augmented by TNF-α pretreatment in a dose-dependent manner, and reduced by AMD3100, an antagonist of CXCR4. These results suggest that KIM-1 is a potential chemo-ligand of CXCR4 and may play an important role in kidney-specific migration of MSCs via interaction between KIM-1 and CXCR4.     

Prohibitin对非小细胞肺癌细胞增殖和凋亡的影响

目的:研究Prohibitin对非小细胞肺癌株A549和NCI-H460细胞增殖和凋亡的影响.方法:将针对Prohibitin的特异性的干扰片段瞬时转染非小细胞肺癌A549和NCI-H460细胞株,以瞬时转染与Prohibitin没有同源性的干扰片段的细胞作为阴性对照,通过免疫蛋白印迹检测各组细胞Prohibitin和Survivin蛋白的表达情况,通过MTT法检测各组细胞的增殖情况,通过流式仪检测各组细胞的凋亡率.结果:针对Prohibitin基因设计的siRNA片段特异性地沉默该基因的表达,与对照组相比较,干扰组的细胞的增殖活性明显增强.同时与凋亡密切相关的Survivin的表达在沉默掉prohibitin后,在A549和NCI-H460中分别降低了46.3%和54.5%.而干扰prohibitin后导致A549细胞的凋亡率上升了约2%.结论:Prohibitin能显著抑制非小细胞肺癌A549和NCI-H460细胞的增殖,而对凋亡的影响可能并不是通过survivin介导的.     

Up-regulation of kin17 is essential for proliferation of breast cancer

Background

Kin17 is ubiquitously expressed at low levels in human tissue and participates in DNA replication, DNA repair and cell cycle control. Breast cancer cells are characterized by enabling replicative immortality and accumulated DNA damage. However, whether kin17 contributes to breast carcinogenesis remains unknown.

Methodology/Principal Findings

In this study, we show for the first time that kin17 is an important molecule related to breast cancer. Our results show that kin17 expression was markedly increased in clinical breast tumors and was associated with tumor grade, Ki-67 expression, p53 mutation status and progesterone receptor expression, which were assessed in a clinicopathologic characteristics review. Knockdown of kin17 inhibited DNA replication and repair, blocked cell cycle progression and inhibited anchorage-independent growth, while increasing sensitivity to chemotherapy in breast cancer cells. Moreover, kin17 silencing decreased EGF-stimulated cell growth. Furthermore, overexpression of kin17 promoted DNA replication and cell proliferation in MCF-10A.

Conclusions/Significance

Our findings indicate that up-regulation of kin17 is strongly associated with cellular proliferation, DNA replication, DNA damage response and breast cancer development. The increased level of kin17 was not only a consequence of immortalization but also associated with tumorigenesis. Therefore, kin17 could be a novel therapeutic target for inhibiting cell growth in breast cancer.     

MUC1 is involved in trophoblast transendothelial migration

The factors that regulate trophoblast invasion of the uterine vasculature are incompletely understood. In this paper we show that macaque trophoblasts express the mucin, MUC1, and that it is involved in trophoblast-endothelial interaction. Immunocytochemistry, Western blotting and RT-PCR analyses confirmed that MUC1 was expressed by isolated early gestation macaque trophoblasts. MUC1 was also detected in endovascular trophoblasts in sections of placental-decidual tissue during early gestation. A blocking antibody against MUC1 reduced trophoblast adhesion to uterine endothelial cells and also blocked trophoblast transendothelial migration. MUC1 is known to bind to Intercellular Adhesion Molecule-1 (ICAM-1) in other systems. Incubation in the presence of a blocking antibody against Intercellular Adhesion Molecule-1 (ICAM-1) or recombinant ICAM-1 modestly, but significantly, reduced transendothelial trophoblast migration. These results are consistent with the idea that MUC1 is involved in trophoblast adhesion to uterine endothelial cells and in trophoblast transendothelial migration.     

Dickkopf-1 is involved in invasive growth of esophageal cancer cells

Dickkopf-1 (DKK1) is an inhibitor of Wnt/β-catenin signaling pathway. High levels of DKK1 protein were found in a series of cancers. However, the role of DKK1 in the progression of esophageal carcinoma is not fully understood. In the present study, RT-PCR and Western blot were used to detect the expression of DKK1 in esophageal carcinoma tissues, matched adjacent normal esophageal tissues, and esophageal carcinoma cell lines. Our results showed that the expression of DKK1 was upregulated on both mRNA and protein levels in esophageal carcinoma tissues compared with the adjacent normal esophageal tissues, meanwhile, in four esophageal carcinoma cell lines analyzed, expression of DKK1 was detected with different levels. Immunohistochemistry and immunofluoresence revealed that the distribution of DKK1 was mainly in the cytoplasm in both carcinoma tissues and cell lines. To further explore the biological effects of DKK1 on proliferation, cell cycle and invasion capability, we constructed the eukaryotic expression vector pCMV-Tab-2b-DKK1 which can effectively overexpress DKK1. Subsequently, we observed that exogenous expression of DKK1 in EC9706 cell line resulted in an increased rate of proliferation, and S stage and G2/M stage ratio whereas G0/G1 ratio was decreased. In order to evaluate the invasion capability Boyden chamber was analyzed which implied that overexpression of DKK1 resulted in an increase in the invasion ability in EC9706 cell line. Taken together, the study indicates that DKK1 might be a key regulator in the progression of esophageal carcinoma and a potential therapeutic target in esophageal carcinoma.     

Sphingosine kinase 1 is required for migration, proliferation and survival of MCF-7 human breast cancer cells

Sphingosine-1-phosphate (S1P) is a potent lysolipid involved in a variety of biological responses important for cancer progression. Therefore, we investigated the role of sphingosine kinase type 1 (SphK1), the enzyme that makes S1P, in the motility, growth, and chemoresistance of MCF-7 breast cancer cells. Epidermal growth factor (EGF), an important growth factor for breast cancer progression, activated and translocated SphK1 to plasma membrane. SphK1 was required for EGF-directed motility. Downregulation of SphK1 in MCF-7 cells reduced EGF- and serum-stimulated growth and enhanced sensitivity to doxorubicin, a potent chemotherapeutic agent. These results suggest that SphK1 may be critical for growth, metastasis and chemoresistance of human breast cancers.     

Reticulocalbin 1 is required for proliferation and migration of non-small cell lung cancer cells regulated by osteoblast-conditioned medium

Reticulocalbin1 (RCN1) is implicated in tumorigenesis and tumour progression. However, whether RCN1-mediated bone metastasis of non-small cell lung cancer (NSCLC) cells was elusive. Here, we assessed the effect of osteoblast-conditioned medium (CM) on proliferation and migration of NSCLC cell line, NCI-H1299 and NCI-H460 cells, and identified the soluble mediators in CMs from osteoblasts and NSCLC cells using MTT, Clonogenicity, Transwell, wound healing, RT-PCR, and Western blotting assays, and LC-MS/MS analysis, respectively. Furthermore, the role of RCN1 was investigated in NSCLC cells cultured with or without osteoblast-CM. Tumour growth and bone resorption were measured in a nude mouse model bearing NCI-H1299 cells transduced with shRNA/RCN1 vector using in vivo imaging technique and micro-CT. The results showed that RCN1 with a higher abundance in osteoblast-CM, which was present in extracellular vesicles (EVs), enhanced RCN1 expression in NSCLC cells. Osteoblast-CM partially offset the inhibitory effect of RCN1 depletion on proliferation and migration of NSCLC cells. RCN1 depletion-induced endoplasmic reticulum (ER) stress caused by increasing GRP78, CHOP, IRE1α, p-IRE1α, p-PERK and p-JNK, which was positively regulated by self-induced autophagy, contributed to suppression of proliferation and migration in NCI-H1299 cells. Therefore, osteoblasts produced RCN1 to transfer into NSCLC cells partially through EVs, facilitating proliferation and migration of NSCLC cells via blocking ER stress. RCN1 could be required for proliferation and migration of NSCLC cells regulated by osteoblast-CM.     

Up-regulation of DNA2 results in cell proliferation and migration in endometriosis

Journal of Molecular Histology - Accumulating evidence has suggests that women with advanced endometriosis exhibit alterations in the expression of genes in the endometrium compared to healthy...     

AZGP1 is androgen responsive and involved in AR-induced prostate cancer cell proliferation and metastasis

Alpha-2-glycoprotein 1, zinc-binding (AZGP1), known as zinc-alpha-2-glycoprotein (ZAG), is a multifunctional secretory glycoprotein and relevant to cancer metastasis. Little is known regarding the underlying mechanisms of AZGP1 in prostate cancer (PCa). In the present study, we report that AZGP1 is an androgen-responsive gene, which is involved in AR-induced PCa cell proliferation and metastasis. In clinical specimens, the expression of AZGP1 in PCa tissues is markedly higher than that in adjacent normal tissues. In cultures, expression of AZGP1 is upregulated by the androgen-AR axis at both messenger RNA and protein levels. Furthermore, Chip-Seq assay identifies canonical androgen-responsive elements (AREs) at AZGP1 enhancer; and dual-luciferase reporter assays reveal that the AREs is highly responsive to androgen whereas mutations of the AREs abolish the reporter activity. In addition, AZGP1 promotes G1/S phase transition and cell cycle progress by increasing cyclin D1 levels in PCa cells. Functional studies demonstrate that knocking down endogenous AZGP1 expression in LNCaP and CWR22Rv1 cells largely weaken androgen/AR axis-induced cell migration and invasion. In vivo xenotransplantation tumor experiments also show that AZGP1 involves in androgen/AR axis-mediated PCa cell proliferation. Taken together, our study implicates for the first time that AZGP1 is an AR target gene and is involved in androgen/AR axis-mediated cell proliferation and metastasis in primary PCa.     

Yes-associated protein is involved in proliferation and differentiation during postnatal liver development

It is known that the liver undergoes size increase and differentiation simultaneously during the postnatal period. Cells in the liver undergo a period of well-controlled proliferation to achieve the adult liver-to-body weight ratio. The postnatal liver growth is also accompanied by simultaneous hepatic differentiation. However, the mechanisms of liver size regulation and differentiation are not completely clear. Herein we report that yes-associated protein (Yap), the downstream effector of the Hippo Kinase signaling pathway, plays a role in liver size regulation and differentiation during the postnatal liver growth period. Postnatal liver growth was studied in C57BL/6 mice over a time course of postnatal days (PND) 0-30. Analysis of nuclear Yap by Western blot indicated peak Yap activation between PND15-20, which coincided with increased cyclin D1 expression and liver cell proliferation. Analysis of postnatal liver development in Yap(+/-) mice revealed a significant decrease in the liver-to-body weight ratio compared with Yap(+/+) mice at PND15 and -30. Yap(+/-) mice exhibited a significant decrease in postnatal liver cell proliferation, but no change in apoptosis was observed. Furthermore, global gene expression analysis of Yap(+/-) livers revealed a role of Yap in regulation of genes involved in bile acid metabolism, retinoic acid metabolism, ion transport, and extracellular matrix proteins. Taken together, these data indicate that Yap plays a role in both cell proliferation and possibly in hepatic differentiation during postnatal liver development.     

Pyruvate kinase type M2 is upregulated in colorectal cancer and promotes proliferation and migration of colon cancer cells

Pyruvate kinase type M2 (PKM2) has been reported to be involved in aerobic glycolysis and cell growth in various tumors. However, the expression pattern of PKM2 in colorectal cancer (CRC) and the correlation between PKM2 expression and CRC remains unclear. The aim of this study is to investigate PKM2 expression and its possible role in CRC. We found that expression of PKM2 was increased in CRC and the increased PKM2 expression was associated with later stage and lymph metastasis of the tumors. Knockdown of PKM2 suppressed the aerobic glycolysis and decreased lactate production of colon cancer RKO cells. Knockdown of PKM2 repressed proliferation and migration of the cells. Inhibition of PKM2 suppressed xenograft tumor growth of RKO cells in vivo. These results suggest that the expression of PKM2 plays a critical role in development of CRC, and it may provide a growth advantage for colon cancer cells. Thus, PKM2 might be a potential therapeutic target for CRC. ? 2012 IUBMB Life, 64(9): 775-782, 2012.     

Up-regulation of eEF1A2 promotes proliferation and inhibits apoptosis in prostate cancer

Background

eEF1A2 is a protein translation factor involved in protein synthesis, which possesses important function roles in cancer development. This study aims at investigating the expression pattern of eEF1A2 in prostate cancer and its potential role in prostate cancer development.

Methods

We examined the expression level of eEF1A2 in 30 pairs of prostate cancer tissues by using RT-PCR and immunohistochemical staining (IHC). Then we applied siRNA specifically targeting eEF1A2 to down-regulate its expression in DU-145 and PC-3 cells. Flow cytometer was used to explore apoptosis and Western-blot was used to detect the pathway proteins of apoptosis.

Results

Our results showed that the expression level of eEF1A2 in prostate cancer tissues was significantly higher compared to their corresponding normal tissues. Reduction of eEF1A2 expression in DU-145 and PC-3 cells led to a dramatic inhibition of proliferation accompanied with enhanced apoptosis rate. Western blot revealed that apoptosis pathway proteins (caspase3, BAD, BAX, PUMA) were significantly up-regulated after suppression of eEF1A2. More importantly, the levels of eEF1A2 and caspase3 were inversely correlated in prostate cancer tissues.

Conclusion

Our data suggests that eEF1A2 plays an important role in prostate cancer development, especially in inhibiting apoptosis. So eEF1A2 might serve as a potential therapeutic target in prostate cancer.     

A surface phospholipase is involved in the migration of plasmodium sporozoites through cells

Plasmodium sporozoites, injected by mosquitoes into the skin of the host, traverse cells during their migration to hepatocytes where they continue their life cycle. The mechanisms used by the parasite to rupture the plasma membrane of the host cells are not known. Here we report the presence of a phospholipase on the surface of Plasmodium berghei sporozoites (P. berghei phospholipase; Pb PL) and demonstrate that it is involved in the establishment of a malaria infection in vivo. Pb PL is highly conserved among the Plasmodium species. The protein is about 750 amino acids, with a predicted signal sequence and a carboxyl terminus that is 32% identical to the vertebrate lecithin:cholesterol acyltransferase, a secreted phospholipase. Pb PL contains a motif characteristic of lipases and a catalytic triad of a serine, aspartate, and histidine that is found in several phospholipases. We have verified its lipase and membrane lytic activity in vitro, using recombinant baculovirus-expressed protein. To study its role in vivo, we have disrupted the P. berghei PL open reading frame and generated mutants in its active site. During an infection through mosquito bite, the infectivity of the knock-out parasites in the liver is decreased by approximately 90%. The prepatent period of the resulting blood infection is 1 day longer as compared with wild type. Further, the mutant sporozoites are impaired in their ability to cross epithelial cell layers. Thus, the Pb PL functions as a lipase to damage cell membranes and facilitates sporozoite passage through cells during their migration from the skin to the bloodstream.