Efficiency of transgene expression in bovine cells varies according to cell type and gene transfer method / La eficiencia de la expresión transg é nica en células bovinas varía según el tipo de célula y el método de la transferencia de genes / A eficiência da expressão do transgene em células bovinas varia de acordo com o tipo celular e o método de transferência gênica

Abstract Background: Production of transgenic animals is still a low-efficiency biotechnology, and simple alternatives should be used to improve the rate of transgenic bovine production by nuclear transfer. One such alternative is selecting the appropriate donor cell type and transfection method. Objective: To investigate the effect of cell type (fetal or adult fibroblasts, and cumulus cells), and gene transfer method (lipofection and lentiviral transduction) on the incorporation, expression, and fluorescence intensity of transgene on bovine cells analyzed by flow cytometry. Methods: Fetal fibroblasts (FF), adult fibroblasts (AF), and cumulus cells (CC) were transfected using lipofection, or transduced using lentiviral particles produced with Green Fluorescent Protein (GFP) expressing plasmids, and analyzed by flow cytometry. Results: Lentiviral transduction resulted in higher transgene expression rates for all cell types (FF: 88.8 ± 0.98; AF: 91.6 ± 2.96; CC: 60.7% ± 14.7) compared to lipofection (FF: 17.8 ± 2.82; AF: 10.66 ± 0.65; CC: 3.9% ± 1.97). Cumulus cells showed lower transgene expression rates than the other cell types. Regarding fluorescence intensity, there was no significant difference between lipofection and lentiviral transduction; in both treatments, higher fluorescence intensity was obtained when adult cells were used instead of fetal cells. Conclusion: Gene transfer efficiency varies according to cell type, and gene transfer method, with lentiviral transduction achieving higher transgene expression rate, and adult fibroblasts showing better transgene expression.

Resumen Antecedentes: La producción de animales transgénicos sigue siendo una biotecnología de baja eficiencia, y se deberían utilizar alternativas sencillas para mejorar la tasa de producción de bovinos transgénicos mediante transferencia nuclear. Una de estas alternativas es la selección del tipo mas apropiado de célula donante y método de transferencia génica. Objetivo: Investigar el efecto del tipo celular (fibroblastos fetales o adultos, y celulas del cumulus), y el método de transferencia génica (lipofección y transducción lentiviral) en la incorporación, expresión génica, y la intensidad de fluorescencia del transgén en células bovinas analizadas por citometría de flujo. Métodos: Fibroblastos fetales (FF), fibroblastos adultos (AF), y células del cúmulo (CC) fueron transfectados a través de lipofección o transducidos utilizando partículas lentivirales producidas con plásmidos que expresan la proteína verde fluorescente (GFP). Resultados: La transducción lentiviral dio lugar a mayores tasas de expresión del transgen en todos los tipos de células (FF: 88,8 ± 0,98; AF: 91,6 ± 2,96, CC: 60,7% ± 14,7) en comparación con la lipofección (FF: 17,8 ± 2,82; AF: 10,66 ± 0,65; CC: 3,9% ± 1,97). Las células del cúmulus mostraron menores tasas de expresión del transgen que los otros tipos celulares. En cuanto a la intensidad de fluorescencia, no hubo diferencias significativas entre lipofección y transducción lentiviral; en ambos tratamientos, se obtuvo una mayor intensidad de fluorescencia cuando se usaron células adultas en lugar de células fetales. Conclusión: La eficiencia de la transferencia de genes varía según el tipo de célula y el método de transferencia génica, con la transducción lentiviral se logra una mayor tasa de transfección, y los fibroblastos adultos muestran una mejor expresión transgénica.

Resumo Antecedentes: A produção de animais transgênicos é uma biotecnologia que ainda apresenta baixa eficiência e alternativas simples devem ser usadas para o aumento da produção de bovinos transgênicos por transferência nuclear. Uma destas alternativas compreende a seleção do tipo apropriado de célula doadora de núcleo e do método de transferência gênica. Objetivo: Investigar a influência do tipo celular (fibroblastos fetais ou adultos, e células do cumulus), e do método de transferência gênica (transfecção por lipofecção ou transdução lentiviral) na incorporação, expressão, e na intensidade de fluorescência do transgene em células bovinas analisadas por citometria de fluxo. Métodos: Fibroblastos fetais (FF), fibroblastos adultos (AF), e células do cumulus (CC) foram submetidas à lipofecção ou à transfecção lentiviral utilizando plasmídeos expressando a Proteína Fluorescente Verde - GFP). Resultados: A transdução lentiviral resultou em maiores taxas de expressão do transgene em todos os tipos celulares (FF: 88,8 ± 0,98; AF: 91,6 ± 2,96; CC: 60,7% ± 14.7) quando comparada com a lipofeccção (FF: 17,8 ± 2,82; AF: 10,66 ± 0,65; CC: 3,9% ± 1,97). As células do cumulus apresentaram menores taxas de expressão quando comparadas aos outros tipos celulares. Com relação à intensidade de fluorescência, não houve diferença significativa entre a lipofecção e a transdução lentiviral e em ambos os tratamentos as células adultas apresentaram maior intensidade de fluorescência do que as células fetais. Conclusão: A eficiência de transferência gênica varia de acordo com o tipo celular, e com o método de transferência gênica, sendo que a transdução lentiviral resultou em maiores taxas, e que os fibroblastos adultos mostraram melhor expressão do transgene.

An efficient method which can be used to transfect Tibetan minipig embryonic fibroblasts / 中国比较医学杂志

Objective To transfect EGFP gene to porcine embryonic fibroblasts ( PEFs) of Tibetan miniature pigs by Lonza Nucleofector II machine and compare the tansfection efficiency between this method and the lipofection method. Method A plasmid carrying green fluorescent protein ( GFP) was transfected into PEFs of Tibetan miniature pigs via the Lonza Nucleofector II machine ( program U020) and by Lipofectamine 2000.Results 5 hours after nucleofection, green fluorescence was observed, indicating 80%transfecting efficiency in the nucleofection group, which is significantly higher than the lipofection group. Conclusion Nucleofector II machine can efficiently transfect PEFs, provides a reliable method for efficiently generate transgenic Tibetan minipigs.

On the possible involvement of bovine serum albumin precursor in lipofection pathway.

Protein factors involved in lipofection pathways remain elusive. Using avidin-biotin affinity chromatography and mass finger printing analysis technique, herein we report the identification of a 70 kDa size protein (bovine serum albumin precursor, BSAP) which binds strongly with lipoplexes and may play role in lipofection pathway. Using multiple cultured animal cells and three structurally different cationic transfection lipids, we show that the efficiencies of liposomal transfection vectors get significantly enhanced (by ~2.5- to 5.0-fold) in cells pre-transfected with lipoplexes of reporter plasmid construct encoding BSAP. Findings in the cellular uptake experiments in A549 cells cultured in DMEM supplemented with 10% (w/w) BODIPY-labelled BSAP are consistent with the supposition that BSAP enters cell cytoplasm from the cell culture medium (DMEM supplemented with 10% FBS) used in lipofection. Cellular uptake studies by confocal microscopy using BODIPY-labelled BSAP and FITC-labelled plasmid DNA revealed co-localization of plasmid DNA and BSAP within the cell cytoplasm and nucleus. In summary, the present findings hint at the possible involvement of BSAP in lipofection pathway.

Comparison of transfection efficiency of two kinds of cells by lipofection and electroporation / 重庆医学

Objective To compare the transfection efficiency between different transfection methods in human HepG2 and SGC7901/ADM cells so as to provide experimental basis for further study .Methods To electrons fect the enhanced GFP plasmid into HepG2 and SGC7901/ADM cells by lipofection and electroporation methods ,respectively .The survival rates and transfection efficiency were analyzed .Results The efficiency of eGFP vector transfected into HepG2 cells by lipofection was (23 .8 ± 2 .1)% , compared with lipofection method ,the efficiency of eGFP plasmid transfected by electroporation was up to (49 .6 ± 2 .5)% ,and the difference was statistically significant(P<0 .05) .The efficiency of SGC7901/ADM cells by lipofection was (25 .4 ± 1 .3)% ,com‐pared with lipofection method ,the efficiency of electroporation was up to(52 .6 ± 2 .1)% ,and the difference was statistically signifi‐cant(P<0 .05) .This study provides reliable test parameters for electransfection of HepG2 and SGC7901/ADM cells .Conclusion The transfection efficiency of large fragment vector is efficiently improved by electroporation .

La lipofección incrementa la eficiencia de mutagénesis dirigida en células troncoembrionarias de ratón E14 TG2a / Lipofection improves gene targeting efficiency in E14 TG2a mouse embryonic stem cells

Electroporation has been the method of election for transfection of murine embryonic stem cells for over 15 years; however, it is a time consuming protocol because it requires large amounts of DNA and cells, as well as expensive and delicate equipment. Lipofection is a transfection method that requires lower amounts of cells and DNA than electroporation, and has proven to be efficient in a large number of cell lines. It has been shown that after lipofection, mouse embryonic stem cells remain pluripotent, capable of forming germ line chimeras and can be transfected with greater efficiency than with electroporation; however, gene targeting of mouse embryonic stem cells by lipofection has not been reported. The objective of this work was to find out if lipofection can be used as efficiently as electroporation for regular gene targeting protocols. This context compares gene targeting efficiency between these techniques in mouse embryonic stem cells E14TG2a, using a gene replacement type vector. No differences were found in gene targeting efficiency between groups; however, lipofection was three times more efficient than electroporation in transfection efficiency, which makes lipofection a less expensive alternative method to produce gene targeting in mouse embryonic stem cells.

Durante los últimos 15 años se ha demostrado que la electroporación representa el método ideal para la transfección de células troncoembrionarias de ratón; sin embargo, demanda grandes cantidades de ADN y células, así como equipo caro y delicado, ello hace que este proceso sea costoso y laborioso. La lipofección es un método de transfección que requiere menos de células y ADN que la electroporación; asimismo, ha probado ser eficiente en gran número de líneas celulares. Se ha demostrado que después de lipofectar células troncoembrionarias de ratón, éstas mantienen su pluripotencia y son capaces de formar quimeras de línea germinal y se transfectan con mayor eficiencia que con electroporación, pero no se ha notificado la mutagénesis dirigida mediante la lipofección de células troncoembrionarias de ratón. El objetivo del presente trabajo fue saber si la lipofección puede ser utilizada con la misma o mayor eficiencia que la electroporación para los protocolos regulares de mutagénesis dirigida; en este contexto, se compara la eficiencia en mutagénesis dirigida entre estas técnicas en células troncoembrionarias de ratón E14TG2a, utilizando un vector de reemplazo. Entre las células transfectadas no se hallan diferencias en la eficiencia en mutagénesis dirigida entre grupos; sin embargo, los resultados que aquí se ofrecen muestran que la lipofección es tres veces más eficiente en la transfección, lo cual indica que la lipofección es un método alternativo menos costoso para obtener mutagénesis dirigida en células troncoembrionarias de ratón.

Restoration of Hormone Dependency in Estrogen Receptor - Lipofected MDA-MB-231 Human Breast Cancer Cells / 대한암학회지

PURPOSE: The loss of estrogen and progesterone receptors appeats to be associated with a progression to less differentiated and hormone-independent tumors. The gain of hormone independency over time even in estrogen receptor-positive tumors has become another obstacle to endocrine therapy for breast cancer. We tried to regain the hormone dependency in estrogen receptor-negative breast cancer cells by lipofecting estmgen receptor cDNA. MATERIALS AND METHODS: The mutant human estrogen receptor cDNA (pSGS-HEO) was lipofected into estrogen receptor-negative human breast cancer cell line MDA-MB-231, in an attempt to restore their sensitivity to antiestrogen. Then the effects of 17p-estradiol and tamoxifen were studied by counting viable cell numbers after treating the lipofected cell line with either one or together. RESULTS: Culture medium cantaining phenol red, a weak estrogen, has growth advantages compared with culture medium without it. In both culture conditions, cell growth was most profoundly inhibited in 4 days after lipofection with mutant human estrogen receptor cDNA, which was overcome after that day. Tamoxifen, as an antiestrogen, showed a growth inhibitory effect slightly stronger tban combined conditions of tamoxifen and 17- estradiol compared to estrogen-treated group and to control, and the inhibitory effect was lasted 4 days. CONCLUSION: The temporary induction of estrogen receptor by lipofection with pSGS-HEO on estrogen receptor-negative human breast cancer cell line MDA-MB-231 showed negative growth control on these cells by tamoxifen, indicating that liposome-mediated estrogen receptor transfection may be used as a novel therapeutic strategy for hormane independent human breast cancers in the near future.

The Effect of Tamoxifen of the Estrogen Receptor cDNA-Iipofected MDA-MB-231 Human Breast Cancer Cells / 한국유방암학회지

BACKGROUND: The loss of estrogen and progesterone receptors appears to be associated with a progression to less-differentiated and hormone-independent tumors. The gain of hormone independency over time even in estrogen receptor-positive tumors has become another obstacle to endocrine therapy for breast cancer. We tried to regain the hormone dependency in estrogen receptor-negative breast cancer cells by lipofecting estrogen receptor cDNA. MATERIALS AND METHODS: The mutant human estrogen receptor cDNA (pSG5-HE0) was lipofected into estrogen receptor-negative human breast cancer cell line MDA-MB-231, in an attempt to restore their sensitivity to antiestrogen. Then the effects if 17 beta -estradiol and tamoxifen were studied by counting viable cell numbers after treating the lipofected cell line with either one or together. RESULTS: The cell growth was most profoundly inhibited in 4 days after lipofection with mutant human estrogen receptor cDNA, which was overcome after that days. Tamoxifen, as an antiestrogen, showed a growth inhibitory effect slightly strong over combined conditions of tamoxifen and 17 beta estradiol compared to estrogen-treated group and to control. CONCLUSIONS: The temporary induction of estrogen receptor by lipofection with pSG5-HE0 on estrogen receptor-negative human breast cancer cell line MDA-MB-231 showed negative growth control on these cells by tamoxifen, indicating that liposome-mediated estrogen receptor transfection may be used as a novel therapeutic strategy for hormone independent human breast cancers in the near future.