Expression of Nanog gene promotes NIH3T3 cell proliferation

Cells are the functional elements in tissue engineering and regenerative medicine. A large number of cells are usually needed for these purposes. However, there are numbers of limitations for in vitro cell proliferation. Nanog is an important self-renewal determinant in embryonic stem cells. However, it remains unknown whether Nanog will influence the cell cycle and cell proliferation of mature cells. In this study, we expressed Nanog in NIH3T3 cells and showed that expression of Nanog in NIH3T3 promoted cells to enter into S phase and enhanced cell proliferation. This suggests that Nanog gene might function in a similar fashion in mature cells as in ES cells. In addition, it may provide an approach for in vitro cell expansion.     

Identification,purification and partial characterization of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in bovine pulmonary artery smooth muscle

Bovine pulmonary artery smooth muscle tissue possesses the tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) as revealed by immunoblot studies of the cytosolic fraction with polyclonal TIMP-1 antibody. In this report, we described the purification and partial characterization of the inhibitor from the cytosolic fraction of the smooth muscle. This inhibitor was purified by a series of anion-exchange, gel filtration and affinity chromatographic procedure. The purified inhibitor showed an apparent molecular mass of 30 kDa in SDS-PAGE. Amino terminal sequence analysis for the first 22 amino acids of the purified inhibitor was also found to be identical to bovine TIMP-1. This glycosylated inhibitor was found to be active against matrix metallorpoteinase-9 (MMP-9, gelatinase B), the ambient matrix metalloproteinase in the pulmonary smooth muscle. The purified TIMP-1 was also found to be sensitive to pure rabbit and human fibroblast collagenase and type IV collagenase. In contrast, it had minimum inhibitory activity against bacterial collagenase. It was also found to be inactive against the serine proteases trypsin and plasmin. The inhibitor was heat and acid resistant and it had the sensitivity to trypsin degradation and reduction-alkylation.     

Transformation of NIH 3T3 cells by enhanced PAR expression

Prostate androgen regulated (PAR) is a 1038bp novel gene located on chromosome 1 in epidermal differentiation complex. The gene is ubiquitously expressed in normal tissues and is overexpressed in most of their malignant counterparts. PAR cellular function is unknown. Here we report the effect of increased PAR expression induced by transfection of PAR cDNA on NIH3T3 cell phenotype. PAR-NIH3T3 transfectants expressing 3- to 4-fold higher PAR levels compared to controls grew faster in tissue cultures, formed colonies in soft agar, and exhibited a shortening of G1 and S phases of cell cycle and formed tumors in SCID mice. Transfection of NIH3T3 cells with increased ectopic PAR expression with a 22 mer oligonucleotide in antisense orientation with PAR mRNA abrogated their ability to form colonies in soft agar. The data presented here along with our previously reported results on DU145 cells transfected with antisense PAR cDNA suggest that PAR gene behaves like a proto-oncogene.     

Aspects of cellular physiology that influence DNA-mediated gene transfer in NIH3T3 cells

Cellular physiology has a significant influence on the efficiency of various gene transfer procedures, as shown by the fact that transfection efficiency varies dramatically among different cell lines. However, the aspects of cellular physiology which influence the transfection process remain substantially uncharacterized. In this study, NIH3T3 cells were treated with inhibitors of protein synthesis, DNA synthesis, and RNA synthesis to determine the importance of these processes in the calcium-phosphate transfection process. The results suggest that protein synthesis during the first 4 h after DNA addition enhances transfection. In contrast, inhibition of RNA synthesis has no effect on transfection during the first 24 h post-DNA addition. The DNA synthesis inhibitor results remain inconclusive due to a secondary inhibition of an unknown cellular factor. Secondly, agents that destabilize microtubules, microfilaments, and the golgi apparatus were used to determine whether these elements play a role in the transfection process. The results suggest that microtubules are not involved in the transfection process, microfilaments are important but not necessary for the transfection process, and a functional golgi apparatus is essential early in the transfection process. These studies provide a foundation from which further investigations into the cellular processes involved in the uptake and expression of exogenous DNA can proceed.     

Involvement of the specific nucleolar protein SURF6 in regulation of proliferation and ribosome biogenesis in mouse NIH/3T3 fibroblasts

The nucleolar proteins which link cell proliferation to ribosome biogenesis are regarded to be potentially oncogenic. Here, in order to examine the involvement of an evolutionary conserved nucleolar protein SURF6/Rrp14 in proliferation and ribosome biogenesis in mammalian cells, we established stably transfected mouse NIH/3T3 fibroblasts capable of conditional overexpression of the protein. Cell proliferation was monitored in real-time, and various cell cycle parameters were quantified based on flow cytometry, Br-dU-labeling and conventional microscopy data. We show that overexpression of SURF6 accelerates cell proliferation and promotes transition through all cell cycle phases. The most prominent SURF6 pro-proliferative effects include a significant reduction of the population doubling time, from 19.8 ± 0.7 to 16.2 ± 0.5 hours (t-test, p < 0.001), and of the length of cell division cycle, from 17.6 ± 0.6 to 14.0 ± 0.4 hours (t-test, p < 0.001). The later was due to the shortening of all cell cycle phases but the length of G1 period was reduced most, from 5.7 ± 0.4 to 3.8 ± 0.3 hours, or by ～30%, (t-test, p < 0.05). By Northern blots and qRT-PCR, we further showed that the acceleration of cell proliferation was concomitant with an accumulation of rRNA species along both ribosomal subunit maturation pathways. It is evident, therefore, that like the yeast homologue Rrp14, mammalian SURF6 is involved in various steps of rRNA processing during ribosome biogenesis. We concluded that SURF6 is a novel positive regulator of proliferation and G1/S transition in mammals, implicating that SURF6 is a potential oncogenic protein, which can be further studied as a putative target in anti-cancer therapy.     

Transformed phenotype conferred to NIH/3T3 cells by ectopic expression of heparin-binding growth factor 1/acidic fibroblast growth factor

Summary Heparin-binding growth factor 1 (HBGF-1), also known as acidic fibroblast growth factor, is a potent mitogen and angiogenic factor found in tissues such as brain, kidney and heart. The genomic and cDNA sequences indicate that HBGF-1 does not have a typical signal peptide sequence. HBGF-1 was shown to be localized to the extracellular matrix of cardiac myocytes, but the mechanism of secretion is not presently known. We have cloned the HBGF-1 cDNA which allowed us to directly test the biological activity, mechanism of secretion and transforming potential of the recombinant protein. A previous report showed that the truncated HBGF-1 confers partial transformed phenotype to the recipient fibroblasts. However, expression of full-length HBGF-1 has not been reported. The HBGF-1 coding sequence was cloned into the retroviral expression vector, SVX, and transfected into NIH/3T3 cells. Transfectants expressing full-length HBGF-1 protein at high levels form foci and grow to a higher cell density than the parental NIH/3T3 cells. Western blotting analysis showed that the recombinant HBGF-1 is a unique band of approximately 20 kDa and can be detected in the cell homogenate but not in the conditioned medium. NIH/3T3 cells were conferred anchorage independence when HBGF-1 was provided exogenously. We showed the transformed cells are capable of growing on soft agar even in the absence of exogenously-provided HBGF-1. Transfected cells expressing HBGF-1 also induced tumor formation when injected into nude mice. Thus, NIH/3T3 cells acquired a full spectrum of transformed phenotype when full length HBGF-1 was expressed at high levels. This work was supported by grants from the National Cancer Institute (RO1 CA45611), The March of Dimes Birth Defects Foundation (No. 6-549) and The Ohio Cancer Research Associates, Inc. I.-M.C. is a recipient of The Research Career Development Award (KO4 CA01369) from the National Institutes of Health.     

EphA3基因稳定表达细胞模型的建立与分析

目的：建立稳定表达外源EphA3基因的小鼠成纤维细胞株模型,初步探讨EphA3基因表达对肿瘤发生、发展的影响。方法：通过脂质体介导的方法,将真核表达载体pcDNA3.1（-）/myc-his-EphA3转染NIH3T3细胞,用Western印迹确定外源EphA3基因表达;通过MTT实验、软琼脂集落形成实验,观察EphA3基因表达对NIH3T3细胞生物学特性的影响。结果：建立了稳定转染EphA3基因的NIH3T3细胞株;EphA3基因表达的小鼠成纤维NIH3T3细胞生长速度没有明显变化,但在软琼脂上锚着非依赖生长的能力加强。结论：建立了稳定表达外源EphA3基因的NIH3T3细胞株,EphA3基因稳定表达具有诱导正常NIH3T3细胞发生恶性转化的重要生物功能。     

DDA1, a novel oncogene,promotes lung cancer progression through regulation of cell cycle

Lung cancer is globally widespread and associated with high morbidity and mortality. DDA1 (DET1 and DDB1 associated 1) was first discovered and registered in the GenBank database by our colleagues. DDA1, an evolutionarily conserved gene, might have significant functions. Recent reports have demonstrated that DDA1 is linked to the ubiquitin–proteasome pathway and facilitates the degradation of target proteins. However, the function of DDA1 in lung cancer was previously unknown. This study aimed to investigate whether DDA1 contributes to tumorigenesis and progression of lung cancer. We found that the expression of DDA1 in normal lung cells and tissue was significantly lower than that in lung cancer and was associated with poor prognosis. DDA1 overexpression promoted proliferation of lung tumour cells and facilitated cell cycle progression in vitro and subcutaneous xenograft tumour progression in vivo. Mechanistically, this was associated with the regulation of S phase and cyclins including cyclin D1/D3/E1. These results indicate that DDA1 promotes lung cancer progression, potentially through promoting cyclins and cell cycle progression. Therefore, DDA1 may be a potential novel target for lung cancer treatment, and a biomarker for tumour prognosis.     

S100A6 (calcyclin) deficiency induces senescence‐like changes in cell cycle,morphology and functional characteristics of mouse NIH 3T3 fibroblasts

S100A6 (calcyclin) is a calcium binding protein with two EF‐hand structures expressed mostly in fibroblasts and epithelial cells. We have established a NIH 3T3 fibroblast cell line stably transfected with siRNA against S100A6 to examine the effect of S100A6 deficiency on non‐transformed cell physiology. We found that NIH 3T3 fibroblasts with decreased level of S100A6 manifested altered cell morphology and proliferated at a much slower pace than the control cells. Cell cycle analysis showed that a large population of these cells lost the ability to respond to serum and persisted in the G0/G1 phase. Furthermore, fibroblasts with diminished S100A6 level exhibited morphological changes and biochemical features of cellular senescence as revealed by β‐galactosidase and gelatinase assays. Also, S100A6 deficiency induced changes in the actin cytoskeleton and had a profound impact on cell adhesion and migration. Thus, we have shown that the S100A6 protein is involved in multiple aspects of fibroblast physiology and that its presence ensures normal fibroblast proliferation and function. J. Cell. Biochem. 109: 576–584, 2010. © 2009 Wiley‐Liss, Inc.     

Synthesis and secretion by mouse 3T3 cells of an inhibitor of cell growth (mIGFBP-3): correlation with cell proliferation.

Our results show that stimulation by serum of dense cultures of 3T3 cells rapidly induced increased synthesis of a growth inhibitor (mIGFBP-3) capable of binding IGF. mIGFBP-3 was secreted by stimulated cells immediately after its synthesis, and accumulated in the medium. Accumulation of mIGFBP-3 in the medium increased, as a function of growth factor (bFGF, PDGF, insulin) concentrations and time. bFGF was the best stimulatory factor for both DNA synthesis and accumulation of mIGFBP-3 in the first 24 h of incubation. DNA synthesis was arrested after 48 h of incubation with bFGF when accumulation of mIGFBP-3 was maximal. Since we showed that mIGFBP-3 is able to inhibit bFGF stimulation of DNA synthesis in mouse fibroblasts, it is possible that the accumulation of mIGFBP-3 induces a feedback regulation of cell growth.     

miR-21-5p inhibits neuropathic pain development via directly targeting C-C motif ligand 1 and tissue inhibitor of metalloproteinase-3

MicroRNAs (miRNA) play important roles in neuroinflammation and neuropathic pain development; however, the underlying mechanism requires further investigation. The expression of miR-21-5p was remarkably upregulated in chronic constrictive injury (CCI) rat model. A significant alleviated neuropathic pain development and reduced the expression of cytokines was observed in CCI rat after exogenous injection of miR-21-5p mimic. The dual-luciferase analysis revealed that tissue inhibitor of metalloproteinase-3 (TIMP3) and chemokines C-C motif ligand 1 (CCL1) was direct downstream target of miR-21-5p. Moreover, silencing of TIMP3 and CCL1 could rescue mechanical allodynia, thermal hyperalgesia and cytokine release in CCI rat, suggesting that TIMP3 and CCL1 exert their function by mediating neuroinflammation in neuropathic pain development. Therefore, we have identified a novel miR-21-5p–CCL1/TIMP3-cytokine axis in regulation of neuropathic pain development in CCI rat model, which is valuable for enhancing our understanding of neuropathic pain and developing miRNAs as potential therapeutic options in the future.     

人MCP cDNA在NIH3T3细胞中表达及功能研究

通过构建表达人膜辅因子蛋白ＭＣＰ编码区全长ｃＤＮＡ的重级载体ｐｃＤＮＡ３ＭＣＰ,以磷酸钙沉淀法转染ＮＩＨ３Ｔ３细胞,用Ｇ４１８筛选阳性克隆,并鉴定ＭＣＰ ｃＤＮＡ在细胞中的表达。将血清梯度稀释并与细胞孵育,然后检测细胞活力：灭活的人血清不能引起对照细胞与ＭＣＰ转染细胞的胞毒作用,而新鲜人血清可使对照细胞发生补体依赖的细胞毒反应,ＭＣＰ转染细胞由于ＭＣＰ蛋白的合成,细胞受到保护不发生该反应。另外,Ｍ     

UHRF1 is regulated by miR-124-3p and promotes cell proliferation in intrahepatic cholangiocarcinoma

Ubiquitin-like with PHD and ring finger domains 1 (UHRF1) is abnormally overexpressed in multiple cancers and closely correlated with tumor-promoting effects, such as high proliferation. However, how UHRF1 functions in intrahepatic cholangiocarcinoma (ICC) has not yet been determined. Herein, we found that UHRF1 is overexpressed in ICC tissues. Downregulated UHRF1 attenuated the transition of the G1/S cell cycle and then suppressed cell proliferation in vitro and tumor growth in vivo. Moreover, upstream regulators of the UHRF1 expression were predicted, and we found that direct binding of miR-124-3p inhibited the UHRF1 expression. Elevated miR-124-3p suppressed proliferation and led to the arrest of the cell cycle. Furthermore, the expression of UHRF1 was positively correlated with PCNA. Clinically, we showed that elevated UHRF1 was associated with poor prognosis, and served as an independent prognostic factor in ICC patients. Together, these findings demonstrate that UHRF1, regulated by miR-124-3p, acts as a tumor promoter by promoting cell proliferation in ICC.     

The effect of 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline on cell growth, cell cycle, induction of DNA fragmentation, and activity of caspase 3 in murine leukemia L1210 cells and fibroblast NIH-3T3 cells

Quinazolines are multitarget agents, which have broad spectrum of biological activity, and some of them are now in cancer clinical testing. 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline is a new synthetically prepared derivative, which in our previous study showed cytotoxic effects on cancer cell lines HeLa and B16. Quinazoline, at micromolar concentrations, induced morphological changes and necrosis of B16 cells, and at nanomolar concentrations it produced changes of F-actin cytoskeleton. It did not cause changes in the cell cycle, did not induce apoptotic cell death in B16 cells, did not have a mutagenic effect, and did not even behave as a typical intercalating agent. Little significant reduction of tumor volume in intramuscular transplanted B16 cells was observed. The aim of the present study was to examine the cytotoxic effect of 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline on murine leukemia L1210 cells and fibroblast NIH-3T3 cells. Induction of cell morphology and cell cycle changes, induction of apoptosis and caspase 3 activity were studied. Quinazoline acted cytotoxically on both cell lines. The sensitivity of leukemia L1210 cells to the quinazoline was higher than that of fibroblast NIH-3T3. The IC(100) was 12 microM for L1210 cells and 24 microM for NIH-3T3 cells. No effect of quinazoline on the cell cycle profile of L1210 and NIH-3T3 was detected, however, quinazoline induced an increase of the sub-G(0) cell fraction, apoptotic DNA fragmentation, and apoptotic morphological changes at a concentration of 12 microM. This quinazoline concentration induced caspase 3 activity. Our results demonstrated that induction of apoptotic cell death via activation of caspase 3 contributed to the cytotoxic effects of 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline in murine leukemia L1210 cells.     

Yak OXGR1 promotes fibroblast proliferation via the PI3K/AKT pathways

Oxoglutarate receptor 1 (OXGR1), as one of the intermediates in G protein-coupled receptors (GPCRs), plays a crucial role in the citric acid cycle receptor of α-ketoglutarate and metabolism. GPCR can control the cell proliferation by regulating the downstream signaling of G protein signaling pathways. The PI3K/AKT pathway transmits the downstream signals of GPCRs and receptor tyrosine kinases. However, the specific role of OXGR1 promoting cell proliferation and differentiation are still unknown. In current study, the over-expression vector and knockdown sequence of yak OXGR1 were transfected into yak fibroblasts, and the effects were detected by a series of assays. The results revealed that OXGR1 expression in yak lung parenchyma tissue was significantly higher than that of other tissues. In yak fibroblasts, the upregulated expression of OXGR1 resulted in activating the PIK3CG (downstream signal) of the PI3K/AKT1 pathway that can upregulated the expression of proliferation genes ( CDK1, PCNA, and CyclinD1) and promote cell proliferation. Conversely, the downregulated expression of OXGR1 inhibited cell proliferation via PI3K/AKT1 pathway. Cell cycle and cell proliferation assays demonstrated that over-expression of OXGR1 can enhanced the DNA synthesis and promoted yak fibroblasts proliferation. While the conversely, knockdown of OXGR1 can decreased DNA synthesis and inhibited cell proliferation. These results illustrated that changes of OXGR1 expression can trigger the fibroblasts proliferation via PI3K/AKT signaling pathway, which indicating that OXGR1 is a novel regulator for cell proliferation and differentiation. Furthermore, these results provide evidence supporting the functional role of GPCRs-PI3K-AKT1 and OXGR1 in cell proliferation.     

Rapid G0/1 transition and cell cycle progression in CD8+ T cells compared to CD4+ T cells following in vitro stimulation

T‐cell population consists of two major subsets, CD4⁺ T cells and CD8⁺ T cells, which can be distinguished by the expression of CD4 or CD8 molecules, respectively. Although they play quite different roles in the immune system, many of their basic cellular processes such as proliferation following stimulation are presumably common. In this study, we have carefully analyzed time–course of G0/1 transition as well as cell cycle progression in the two subsets of quiescent T‐cell population following in vitro growth stimulation. We found that CD8⁺ T cells promote G0/1 transition more rapidly and drive their cell cycle progression faster compared to CD4⁺ T cells. In addition, expression of CD25 and effects of its blockade revealed that IL‐2 is implicated in the rapid progression, but not the earlier G0/1 transition, of CD8⁺ T cells.     

鸡平滑肌肌球蛋白轻链激酶在NIH 3T3细胞中的表达

肌球蛋白轻链激酶（ＭＬＣＫ）在调节平骨肌细胞收缩过程中具有十分重要的作用。本言语通过将ＭＬＣＫｃＤＮＡ插到质粒ｐＢＫｒｓｖ中构建ｐＢＫｒｓｖ－ＭＬＣＫ,并转染至ＮＩＨ３Ｔ３细胞中,ＤＮＡ－ＰＣＲ、ＲＴ－ＰＣＲ和Ｗｅｓｔｅｒｎ ｂｌｏｔ分析表达转染细胞可表达ＭＬＣＫ。活生分析表明所表达的ＭＬＣＫ具有生物学活性。为进一步研究ＭＬＣＫ在信号传导,调节平骨肌收缩等作用奠定了基础。