Establishment of primary prostate epithelial and tumorigenic cell lines using a non-viral immortalization approach

Background Research on prostate cancer is mostly performed using cell lines derived from metastatic disease, not reflecting stages of tumor initiation or early progression. Establishment of cancer cell lines derived from the primary tumor site has not been described so far. By definition, cancer cells are able to be cultured indefinitely, whereas normal epithelial cells undergo senescence in vitro. Epithelial cells can be immortalized, accomplished by using viral integration of immortalization factors. Viral approaches, however, might be impaired by regulatory and safety issues as well as random integration into regulatory genetic elements, modifying precise gene expression. We intend to use surgical specimen of prostate cancer patients to (i) prove for establishment of cancer cell lines, and (ii) perform nonviral, Sleeping Beauty (SB) transposase-based immortalization of prostate epithelial cells. Methods Radical prostatectomy samples of prostate cancer patients (n = 4) were dissociated and cultured in vitro. Cells were cultivated either without or after non-viral, Sleeping-Beauty transposase-based stable transfection with immortalization factors SV40LT and hTERT. Established cell lines were analyzed in vitro and in vivo for characteristics of prostate (cancer) cells. Results Initial cell cultures without genetic manipulation underwent senescence within ≤ 15 passages, demonstrating inability to successfully derive primary prostate cancer cell lines. By using SB transposase-based integration of immortalization factors, we were able to establish primary prostate cell lines. Three out of four cell lines displayed epithelial characteristics, however without expression of prostate (cancer) characteristics, e.g., androgen receptor. In vivo, one cell line exhibited tumorigenic potential, yet characteristics of prostate adenocarcinoma were absent. Conclusion Whereas no primary prostate cancer cell line could be established, we provide for the first-time immortalization of primary prostate cells using the SB transposase system, thereby preventing regulatory and molecular issues based on viral immortalization approaches. Although, none of the newly derived cell lines demonstrated prostate cancer characteristics, tumor formation was observed in one cell line. Given the non-prostate adenocarcinoma properties of the tumor, cells have presumably undergone oncogenic transformation rather than prostate cancer differentiation. Still, these cell lines might be used as a tool for research on prostate cancer initiation and early cancer progression.

Role and mechanism of focal adhesion kinase in inducing osteogenic differentiation of mouse embryonic fibroblasts cells / 中国组织工程研究

BACKGROUND: Focal adhesion kinase (FAK) is regarded as a bridge molecule of “biomaterial/scaffold,” “seed cell,” and “growth factor” in bone tissue engineering. Exploration on the role and mechanism of focal adhesion kinase in inducing osteogenic differentiation of related seed cells is particularly important for the development and application of bone tissue engineering. OBJECTIVE: To determine the role and mechanism of FAK in inducing osteogenic differentiation of immortalized mouse embryonic fibroblasts (iMEF). METHODS: Under the same induction conditions, the iMEF cells with (iMEFFAK+/+ cells) or without FAK knockout (iMEFFAK-/- cells), treated with or without PI3K/ AKT phosphorylation inhibitor LY294002 or ERK1/2 phosphorylation inhibitor U0126, were induced to differentiate into osteoblasts. The morphological changes of iMEFs (iMEFFAK+/+ and iMEFFAK-/-) at different induction periods were observed under a microscope. Runx2 protein levels and corresponding p-ERK1/2 and p-AKT levels were detected by western blot. RT-PCR technology was used to detect the transcription level of Runx2 gene. Finally, the induced iMEFs (iMEFFAK+/+ and iMEFFAK-/-) were stained with alizarin red staining for calcium nodules 3 weeks after osteogenesis induction. RESULTS AND CONCLUSION: The osteogenic effect of iMEFFAK-/- cells was lower than that of iMEFFAK+/+ cells under the same induction conditions. Both the expression levels of Runx2 and the osteogenic effect of iMEFFAK+/+ cells and iMEFFAK-/- cells treated with LY294002 decreased significantly compared with the control group. Both the expression levels of Runx2 and the osteogenic effect of iMEFFAK+/+ cells and iMEFFAK-/- cells treated with U0126 decreased significantly compared with the control group. To conclude, silencing FAK expression can inhibit osteogenic differentiation of mouse embryonic fibroblasts by reducing the levels of PI3K/AKT, serine/threonine protein kinase, and ERK1/2 phosphorylation levels.

Advances in immortalization of human B cells / 生物工程学报

With the advantages of low immunogenicity and long half-life, human monoclonal antibody has become an indispensable biological agent in vivo. Immortalization of human B cells is a potential and effective method to obtain natural human antibody library, which can provide a rich source for the preparation of human monoclonal antibodies. As there are urgent problems to be solved in each platform, the preparation of antibodies based on human B cell immortalization is still limited to the laboratory research stage. At present, there is a lack of a systematic review to clarify the advantages and disadvantages of the existing human B cell immortalization antibody preparation platform and its feasibility analysis. This paper reviews the research on the preparation of human monoclonal antibody based on human B cells immortalization, and describes an in vitro cell culture method, in which hCD40L vesicles are used instead of feeder cells, in order to provide references for the further development of human monoclonal antibody preparation technology.

Alternatives for obtaining a continuous cell line from Apis mellifera / Alternativas para a obtenção de uma linhagem celular contínua de abelhas Apis mellifera

ABSTRACT: In worldwide there are reports of a significant decrease in colonies of the species Apis mellifera, caused by several factors, including viral infections. In order to study and diagnose illnesses caused by viruses, in vitro cell culture is used as a valuable tool. Yet, there are still no immortalized cell lines of honey bee Apis mellifera. Primary cell cultures are promising for this purpose and can supply the lack of continuous strains, but their establishment is difficult and laborious, which often makes them unfeasible for many research centers. Through the use of cell immortalization techniques, it is possible to develop continuous cell lines and thus benefit, in different ways, research related to different species of bees. The choice of technique is challenging, since in addition to the ability to remain viable for countless passages, cells must keep the genotype and phenotype similar or identical to the original tissue. This review intends to present methodologies that can be used to immortalize Apis mellifera cells, aiming to establish a cell line. The genotypic and phenotypic implications of each technique are evaluated, and the purpose of the cell line to be developed.

RESUMO: Ao redor do mundo há relatos da diminuição significativa de colônias da espécie Apis mellifera, causada por diversos fatores, incluindo infecções virais. Para estudo e diagnóstico de enfermidades causadas por vírus utiliza-se, como uma ferramenta valiosa, o cultivo celular in vitro. Contudo, ainda não existem linhagens celulares imortalizadas de abelhas Apis mellifera. Os cultivos celulares primários são promissores para este fim e podem suprir a falta de linhagens contínuas, porém seu estabelecimento é difícil e laborioso o que, muitas vezes, os torna inviáveis para muitos centros de pesquisa. Através do uso de técnicas de imortalização celular é possível desenvolver linhagens contínuas de células e assim beneficiar, de diversas formas, as pesquisas relacionadas às diferentes espécies de abelhas. A escolha da técnica é desafiadora, visto que, além da capacidade de permanecer viável por inúmeras passagens, as células devem manter o genótipo e fenótipo semelhante ou idêntico ao tecido original. O objetivo deste trabalho é apresentar metodologias que podem ser utilizadas para imortalização de células de Apis mellifera, visando o estabelecimento de uma linhagem celular. São avaliadas as implicações genotípicas e fenotípicas de cada técnica, e a finalidade da linhagem celular a ser desenvolvida.

Diffuse Intrinsic Pontine Gliomas Exhibit Cell Biological and Molecular Signatures of Fetal Hindbrain-Derived Neural Progenitor Cells / 神经科学通报·英文版

Diffuse intrinsic pontine glioma (DIPG) is the main cause of brain tumor-related death among children. Until now, there is still a lack of effective therapy with prolonged overall survival for this disease. A typical strategy for preclinical cancer research is to find out the molecular differences between tumor tissue and para-tumor normal tissue, in order to identify potential therapeutic targets. Unfortunately, it is impossible to obtain normal tissue for DIPG because of the vital functions of the pons. Here we report the human fetal hindbrain-derived neural progenitor cells (pontine progenitor cells, PPCs) as normal control cells for DIPG. The PPCs not only harbored similar cell biological and molecular signatures as DIPG glioma stem cells, but also had the potential to be immortalized by the DIPG-specific mutation H3K27M in vitro. These findings provide researchers with a candidate normal control and a potential medicine carrier for preclinical research on DIPG.

Immortalization of spleen fibroblastic reticular cells infected by severe fever thrombocytopenia syndrome virus / 中华实验和临床病毒学杂志

Objective@#To isolate, purify and culture fibroblastic reticular cells (FRCs) of mouse in spleen, to develop a reliable and robust method to immortalize primary mouse FRCs, to filter stable FRCs cell lines, to prove that the clones can be infected by SFTSV in vitro.@*Methods@#After purifying FRCs by fluorescence activated cell sorting (FACS) from autoMACS-enriched stroma cells of mouse spleen, we infected FRCs by simian virus 40 large T antigen in vitro, screened the FRCs clones with puromycin, compared primary and immortalized FRCs by RNA sequencing(RNA-seq) technology, infected the clones with severe fever with thrombocytopenia syndrome virus (SFTSV) in vitro.@*Results@#We succeed in culturing purified FRCs from spleen, isolated four stable FRCs clones, two of which have a purity of 99%, survived for more than 50 passages, express the key FRCs marker podoplanin and do not express CD31 and CD45. Clone 01 lost the typical FRCs-like morphology, the rate of expansion of which is quite different from that of primary FRCs and Clone 02. Clone 02 can be infected with SFTSV, which has the same gene expression pattern and immunophenotype with primary FRCs.@*Conclusions@#The stable FRCs clone Clone 02 has FRCs-like morphology and express key FRCs surface markers podoplanin (GP38 or PDPN) and do not express endothelial cell markers CD31 and leukocyte common antigen CD45. The RNA expression profiles identified by RNA-seq are also characteristic of FRCs. Infected with SFTSV in vitro, Clone 02 will be a new platform to study SFTSV.

Establishment of Immortalized Primary Human Foreskin Keratinocytes and Their Application to Toxicity Assessment and Three Dimensional Skin Culture Construction

In spite of frequent usage of primary human foreskin keratinocytes (HFKs) in the study of skin biology, senescence-induced blockage of in vitro proliferation has been a big hurdle for their effective utilization. In order to overcome this passage limitation, we first isolated ten HFK lines from circumcision patients and successfully immortalized four of them via a retroviral transduction of high-risk human papillomavirus (HPV) E6 and E7 oncogenes. We confirmed expression of a keratinocyte marker protein, keratin 14 and two viral oncoproteins in these immortalized HFKs. We also observed their robust responsiveness to various exogenous stimuli, which was evidenced by increased mRNA expression of epithelial differentiation markers and pro-inflammatory genes in response to three reactive chemicals. In addition, their applicability to cytotoxicity assessment turned out to be comparable to that of HaCaT cells. Finally, we confirmed their differentiation capacity by construction of well-stratified three dimensional skin cultures. These newly established immortalized HFKs will be valuable tools not only for generation of in vitro skin disease models but also for prediction of potential toxicities of various cosmetic chemicals.

Effects of human papillomavirus E5 gene on EGFR, p21, p53 and Rb gene expression in immortalized oral epithelial cells / 安徽医科大学学报

Objective To investigate the effects of HPV16 E5 on the expression of EGFR,p21,p53 and Rb in the human immortalized oral epithelial cell(HIOEC),and to discuss the potential mechanism of HPV16 E5 in the occurrence and development of oral squamous cell carcinoma.Methods Open reading frame of HPV16 E5 was cloned into the lentiviral vector pLOV-N to prepare recombinant plasmid pLOV-E5,which was stably transfected into HIOEC.EGFR,p21,p53 and Rb were detected by RT-qPCR and Western blot on the mRNA level and the protein level,respectively.Cell proliferation after stable trasfection was evaluated by MTT assay.Results After stable trasfection of HPV16 E5,the protein levels of EGFR,p21 and p53 in HIOEC were markedly overexpressed,as well as the mRNA levels of p21 and p53 (P =0.00,0.02).However,the mRNA levels of EGFR had no obvious change after trasfection.There were also no significant changes of Rb on the mRNA and protein levels.Compared with the control ceils,the proliferation activity of HIOEC/pLOV-E5 cells was significantly increased (P =0.00).Conclusion HPV16 E5 can stimulate the expression of EGFR,p21 and p53 as well as the proliferation of HIOEC.

Construction of human mucosa oral epithelial cell lines overexpressing telomerase reverse transcriptase gene mediated by lentivirus / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To construct a cell line of oral mucosa epithelial cells that stably express human telomerase reverse transcriptase (hTERT) by lentiviral vectors, approaches for the establishment of stable and efficient immortalized oral mucosa epithelial cell lines were explored.</p><p><b>METHODS</b>Whole RNA was extracted from 293T cells. The hTERT gene was amplified by polymerase chain reaction (PCR) and cloned into the lentiviral vector as pLVX-puro-hTERT. The lentivirus particles were successfully packaged and used to infect primary oral epithelial cells. The positive cell clones were selected by puromycin. Finally, the expression of hTERT was examined by real-time fluorescent quantitative PCR (qRT-PCR) and Western blot analysis.</p><p><b>RESULTS</b>The sequencing results confirmed the construction of the recombinant lentivirus pLVX-puro-hTERT. The morphology of infected cells was similar to that of normal oral mucosal epithelial cells, with a cobble stone-like appearance. The qRT-PCR and Western blot results showed that hTERT was overexpressed in infected cells compared with the normal group (P<0.05).</p><p><b>CONCLUSIONS</b>The oral epithelial cell line with stable expression of hTERT was successfully established by the lentivirus, which provides an experimental basis for the establishment of a highly efficient and stable oral epithelial immortalized cell line.</p>

Research status on Ts-SV40-mediated temperature sensitive cells / 天津医药

The in vitro passage number and proliferation of non-immortalized cells are limited, which restrictions cell therapy or in vitro studies. Cells transfected with temperature sensitive simian virus 40 large T antigen (ts-SV40LT) gene could show the greatest proliferation. The cells can be amplified with compensating the lack of limited number of cells under the permissive temperature. Non-permissive temperature can be used in studying the cell therapy or its other physiological characteristics. This research field involves peritoneal stromal cells, satellite cells of urinary tract, oral epithelial cells, adre?nal medullary cells, bone marrow-derived endothelial cells, retinal progenitor cells, mesenchymal stem cells, hematopoietic stem cells, mast cells, podocytes and Kupffer cells. In this study, the current research on Ts-SV40-mediated temperature-sensitive cells was reviewed.

Immortalization of Primary Keratinocytes and Its Application to Skin Research

As a major component of the epidermal tissue, a primary keratinocyte has served as an essential tool not only for the study of pathogenesis of skin-related diseases but also for the assessment of potential toxicities of various chemicals used in cosmetics. However, its short lifespan in ex vivo setting has been a great hurdle for many practical applications. Therefore, a number of immortalization attempts have been made with success to overcome this limitation. In order to understand the immortalization process of a primary keratinocyte, several key biological phenomena governing its lifespan will be reviewed first. Then, various immortalization methods for the establishment of stable keratinocyte cell lines will be explained. Finally, its application to a three-dimensional skin culture system will be described.

Establishment of canine kidney cell line for canine distemper virus replication / 동물의과학연구지

Kidney cells of canine embryos were separated into single cells using collagenase and dispase. Primary culture was conducted using these cells. To remove fibroblasts, these cells were treated with edetate disodium dihydrate (Na2EDDA), and pure epithelial cells were separated. Recombinant retrovirus particles that manifest teromerase were produced and inoculated into primary culture cells to produce immortalized canine cell strains (JNUCK-1 and JNUCK-2). To examine the characteristics of the produced cell strains, the growth curve, maximum cultured households, and expressed proteins (keratin) were identified. The JNUCK-1 and JNUCK-2 cell lines showed division ability until the 30th generation without growth retardation. JNUCK-1 and JNUCK-2 cell lines clearly expressed telomerase until the 25th generation. The canine distemper virus (CDV) was inoculated into the JNUCK-1 and JNUCK-2 cell lines, as well as in the Madin-Darby canine kidney (MDCK) cell line. The maximum titer of CDV from the JNUCK-1 cell strain was about 200 times higher than that from the MDCK cell strain. However, the JNUCK-2 cell strain produced a lower titer than the MDCK cell strain. We established a new canine kidney epithelial cell line (JNUCK-1) that could produce CDV with high titer.

Telomerase reverse transcriptase mediated immortalization of human bone marrow stromal cells

Primary human bone marrow stromal cells (hMSCs) were transfected with human telomerase reverse transcriptase (hTERT) gene with lipofection method. The hTERT transfected hMSCs of passage 100 underwent chondrogenesis induction with dexamethasone, transforming the growth factor β and vitamin C, osteogenesis induction with dexamethasone, β glycerophosphoric acid and vitamin C, and cardiomyocyte induction with 5-azacytidine. After 7, 14, 21 and 28 days of induction, immunocytochemistry was performed to detect the expressions of type I and II collagen and osteocalcin, and alizarin red staining was performed to detect the bone nodule formation in osteogenesis induction. Immunocytochemistry was carried out to detect the striated muscle actin expression in cardiomyocytes. The hMSCs undergoing successful transfection were positive for the hTERT. The hTERT transfected cells were grown in vitro successfully and passaged for 136 generations. Results showed that these cells could be induced to differentiate into chondrocytes, bone and myocardial cells. Introduction of exogenous hTERT into hMSCs could achieve immortalized hMSCs with the potential of multi-directional differentiation. Thus, these cells could be applied as seed cells in tissue engineering.

Immortalization of human fallopian tube epithelial cells / 中国癌症杂志

10.3969/j.issn.1007-3969.2013.04.00X

Mitochondrial Dysfunction of Immortalized Human Adipose Tissue-Derived Mesenchymal Stromal Cells from Patients with Parkinson's Disease

Mitochondrial dysfunction in dopaminergic neurons of patients with idiopathic and familial Parkinson's disease (PD) is well known although the underlying mechanism is not clear. We established a homogeneous population of human adipose tissue-derived mesenchymal stromal cells (hAD-MSCs) from human adult patients with early-onset hereditary familial Parkin-defect PD as well as late-onset idiopathic PD by immortalizing cells with the hTERT gene to better understand the underlying mechanism of PD. The hAD-MSCs from patients with idiopathic PD were designated as "PD", from patients with Parkin-defect PD as "Parkin" and from patients with pituitary adenomas as "non-PD" in short. The pGRN145 plasmid containing hTERT was introduced to establish telomerase immortalized cells. The established hTERT-immortalized cell lines showed chromosomal aneuploidy sustained stably over two-years. The morphological study of mitochondria in the primary and immortalized hAD-MSCs showed that the mitochondria of the non-PD were normal; however, those of the PD and Parkin were gradually damaged. A striking decrease in mitochondrial complex I, II, and IV activities was observed in the hTERT-immortalized cells from the patients with idiopathic and Parkin-defect PD. Comparative Western blot analyses were performed to investigate the expressions of PD specific marker proteins in the hTERT-immortalized cell lines. This study suggests that the hTERT-immortalized hAD-MSC cell lines established from patients with idiopathic and familial Parkin-defect PD could be good cellular models to evaluate mitochondrial dysfunction to better understand the pathogenesis of PD and to develop early diagnostic markers and effective therapy targets for the treatment of PD.

Immortalization of liver cells: experimental studies and application / 中华肝胆外科杂志

Hepatocyte is the core raw materials of bioartificial liver support system, primary hepatocyte is lim-ited to application because of short survival and difficult cul-ture in vitro. Porcine hepatocyte which has been used re-cently exist the risks of endogenous retrovirus transmission.With the development of molecular biology, it has been pos-sible that hepatocyte is immortalized recently. Immortalized hepatocytes have greatly significant to drug toxicology, bio-artificial liver support system and tissue engineering of liver.Therefore, we will review the prospects for research and ap-plication of immortalized hepatocytes.

Immortalization of Human Precartilaginous Stem Cells by Transfecting SV40Tag / 华中科技大学学报（医学）（英德文版）

Immortalized human precartilaginous stem cells (IPSCs) were established to provide stable cell resource for the study of the molecular mechanism of gene targeting on the differentiation of PSCs.Plasmid pCMVSV40T/PUR containing simian virus 40 large T antigen gene (SV40Tag) was transfected into human PSCs by using lipofectin transfection.Colonies were isolated by puromycin selection and expanded by multiple passages,lmmunohistochemistry,RT-PCR and Southern blotting were used to identify the transfected cells and to detect the expression and integration of SV40Tag in expanded cell lines.The positive colonies were isolated and subcultured,designated immortalized precartilaginous stem cells (IPSCs),which were confirmed as fibroblast growth factor receptor-3 (FGFR-3) positive cells by immunohistochemistry and RT-PCR.SV40Tag cDNA was found in cultured IPSCs of passage 8 by Southern blotting,and the expressions of SV40Tag mRNA and protein were confirmed by RT-PCR.These findings suggested that IPSCs strain with SV40Tag was constructed successfully.

Immortalization of human precartilaginous stern cells by transfecting SV40Tag / 中华创伤骨科杂志

Objective To establish the strain of immortalized human precartilaginous stem cells (PSCs) which can be a stable cell resource for study of the molecular mechanism of gene targeting on differ-entiation of PSCs. Methods Plasmid pCMVSV40T/PUR containing simian virus 40 large T antigen gene (SV40Tag) was transfected into human PSCs using lipofeetin transfection method. Colonies were isolated by puromycin selection and expanded by many passages. Immunohistochemistry, RT-PCR and Southern blot were used to identify the transfected cells and to detect the expression and integration of SV40Tag in expanded cell lines. Results The positive colonies were isolated and subcultured, named as immortalized precartilaginous stem cells (IPSCs), which were confirmed as positive to fibrnblast growth factor receptor-3 (FGFR-3). The existence of SV40Tag cDNA was detected by Southern blot and the expression of SV40Tag mRNA and protein by RT-PCR and immunohistochemistry. Conclusion IPSCs strain with SV40Tag can be constructed successfully.

Immortalization of porcine hepatocyte lines by transfection with simian virus 40 large T antigen and human telomerase reverse transcriptase / 中华传染病杂志

Objective To establish normally immortalized porcine hepatocyte lines by ectopic expression of simian virus 40 large T (SV40LT) antigen and the human telomerase reverse transcriptase(hTERT). Methods Primary porcine Hepatoeyte cells were transfeeted with recombinant retrovirus containing SV40LT or hTERT respectively. Subsequently drug resistant cell clones were screened and expanded for further studies. Immortalized porcine hepatocyte was confirmed by examination. Results The morphological phenotype of the transfected cells was similar to the primary porcine hepatocyte. One clone, HepLP, has been maintained in cultue for half year, and expanded by more than 60 passages. SV40 LT and hTERT could be detected in transfected porcine hepatocyte. Pig albumin mRNA was also detected by RT-PCR. No tumor formation occurred when HepLP cells were injected into Balb/c nude mice. Conclusions The immortalized, nontumorigenic, porcine hepatoeytes maintained the properties of porcine primary hepatocytes such as the albumin secretion. This generation of immortalized porcine hepatocyte may be helpful for bioartifical liver support system, hepatocytes transplantation, drug/toxicological studies, and liver biologic studies.

In vitro Culture of Hepatitis C Virus (HCV) Using Immortalized Hepatocyte / 대한소화기학회지

BACKGROUND/AIMS: It is essential to develop an in vitro culture model of primary hepatocytes for the study of hepatocellular function and the pathogenesis of hepatitis C virus (HCV) infection. In this study, we have established the immortalized primary human hepatocyte (IPHH) and performed in vitro culture of HCV derived from human patient. METHODS: Primary human hepatocytes were isolated from surgically resected liver tissue and then were immortalized by transfection with the SV40 large T antigen. The characterization of the IPHH during culture was analyzed by immunocytochemistry, RT-PCR, Western blot, ELISA, and soft agar assay. Next, sera and/or liver tissue homogenates from surgically resected liver tissues of patients with HCV infection were inoculated for the culture of HCV in IPHH. After HCV RNA extraction from IPHH and culture media, positive or negative stranded HCV RNA was examined by specific nest RT-PCR. RESULTS: IPHH expressed liver-associated proteins but did not express alpha-fetoprotein. Also IPHH showed ammonia removal activity. With regard to its malignant potential, colony formation in soft agar assay was not observed. Next, positive and negative stranded HCV RNAs in IPHH infected with patient's sera plus liver tissue homogenates were clearly detected whereas those in IPHH infected with only patient's sera were not detected. CONCLUSIONS: These results demonstrated the phenotypic characteristics of IPHH and the feasibility in vitro culture system of HCV infected human samples. This system might be useful for study of pathogenesis of HCV infection or hepatocyte-based applications.