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At least 343 records · Page 19Linked to original sources
PubMed1998

Down-regulation of protein kinase C alpha and gamma and enhanced TPA-induced neurite formation in DAN-transfected neuroblastoma cells.

DAN gene was first isolated by differential screening between rat 3Y1 and v-src-transformed 3Y1 cells and showed a tumor-suppressive activity toward v-src-transformed 3Y1 cells. When DAN-transfected neuroblastoma cells were treated with a tumor promoter phorbol ester, TPA, neurite-like processes appeared within 2 h whereas no apparent change was observed in the parent and vector-transfected cells up to 8 h. This suggests some difference in TPA-receptor, protein kinase C (PKC), between DAN-transfectants and the control cells. DAN-transfected SH-SY5Y cells showed complete loss in PKCalpha and a large decrease in PKCgamma. Similar down-regulation in PKCalpha and PKCgamma was also observed in DAN-transfected Ha-ras-transformed NIH 3T3 cells. The decreased level of PKCalpha was partially recovered after treatment with a calpain inhibitor, ZLLH. A 150-kDa proteolytic product of a calpain-specific substrate, non-erythroid alpha-spectrin, was detectable in DAN-transfected SH-SY5Y cells but not in the parent or vector-transfected control cells. This suggests that DAN-transfected cells contain activated calpain which may cause down-regulation of PKC and hence induce the altered TPA response.

3T3 Cells↗
PubMed2001

Improving the transfection efficiency of post-mitotic neurons.

The transfection of post-mitotic cells, including primary cortical and hippocampal neurons, has proven for the most part to be inefficient. Methods such as DNA/Ca++ phosphate co-precipitation, electroporation, cationic lipids and micro-injection are often toxic to the cell and rarely give a transfection efficiency exceeding 3% of the surviving culture. Virus transfection methods using modified viruses such as adeno and semliki-forest virus have been shown to be more efficient but the procedures are often time consuming and virus infections may interfere with protein processing. In this study, we evaluated the transfection efficiency of cells from E18 rat embryonic cortical and hippocampal tissues using three cationic lipids: LIPOFECTAMINE, LIPOFECTAMINE Plus, and LIPOFECTAMINE 2000. The method of transfection was by a traditional reporter gene beta-galactosidase (pCMV.SPORT-beta-gal). Results show that out of the three cationic lipids tested, LIPOFECTAMINE 2000 allows for a significantly higher transfection efficiency. Transfection efficiency with LIPOFECTAMINE or LIPOFECT-AMINE Plus was <3%. In contrast, transfection efficiency with LIPOFECT-AMINE 2000 was approximately 20-25% with the cortical neurons and 25-30% with the hippocampal neurons.

Animals↗
PubMed1999

Conditions providing enhanced transfection efficiency in rat pheochromocytoma PC12 cells permit analysis of the activity of the far-upstream and proximal promoter of the brain creatine kinase gene.

While brain creatine kinase (CKB) is expressed at highest levels in the brain, where it functions in regenerating ATP, the gene elements and protein factors regulating CKB transcription in neuronal and glial cells have not been identified. To investigate the regulation of CKB in neuronal cells, we examined the expression of the promoter proximal and 5' far-upstream regions of the rat CKB gene transiently transfected into rat PC12 pheochromocytoma cells. Initially, these experiments were hampered by the extremely low transfection efficiency of PC12 cells. We increased efficiency by greater than 200-fold by employing CaPO4-precipitated DNA transfection into PC12 cells which were optimized for transient transfection by: (i) culturing cells in polylysine-coated dishes to insure attachment throughout transfection; (ii) exposing cells to transfected DNA for an optimal time and employing a glycerol shock; and, most importantly, (iii) dissociating the characteristic self-adhesive clumps of PC12 into mostly single cells. Use of the plasmid expressing green fluorescent protein allowed identification of the transfected cells that averaged 10-20% of the total. Analyses of CKB promoter-CAT gene constructs showed that in PC12 cells expression of the proximal (0.2 kb) CKB promoter was low while expression of the 1.4 kb promoter was three fold higher and the 2.9 kb promoter was ten fold higher, suggesting the presence of at least two upstream cis-acting, positive regulatory elements. In agreement, the steady-state CKB mRNA level was higher in PC12 than in other neuronal cell lines examined, possibly reflecting the effects of positive upstream factors. The results are discussed in relation to how this economical and straightforward transfection procedure may be useful in identify factors regulating the transcription of CKB and other genes expressed in neuronal cells.

Animals↗
PubMed1997

Mode of transfection influences the stability of ectopically expressed mRNA.

In the study of mRNA metabolism, modified mRNAs are often analyzed after corresponding mRNA expression vectors have been transfected, either transiently or stably, into cells. Two differently transfected templates might be localized in distinct nuclear compartments: in transient transfection they remain in the nucleoplasm while in stable transfection they are integrated in the chromatin. Consequently, nascent transcripts may encounter different environments which may affect the physical state of mRNA and its fate. In this work, we addressed the question whether the two different modes of transfection affect the stability of expressed mRNA. We compared globin mRNA, which is characteristically stable, and globin-delta AU mRNA, which contains the 3' untranslated region of urokinase-type plasminogen activator mRNA and is unstable. In stably transfected cells, these mRNAs were degraded in a manner which mimicked the endogenous mRNA, whereas in transiently transfected cells, the regulated degradation of both mRNAs was impaired. However, when lower amounts of template DNA were used in transient transfection, mRNA was degraded in a manner similar to that of stably expressed mRNA, indicating that mRNA levels affect its stability. To monitor potential differences in the physical state of mRNAs in vivo, we developed a method based on a combination of chemical modification of cellular RNA and a modified RT-PCR. We found that patterns of chemical modification vary with the levels of mRNA expressed. Our results suggest that a proper interaction of mRNA with specific cellular proteins is important for regulated degradation and that overexpression of mRNA destroys such proper stoichiometry.

Animals↗
PubMed1996

Cationic lipid-mediated NGF gene transfection increases neurofilament phosphorylation.

We examined the effect of cationic lipid-mediated gene transfection of nerve growth factor (NGF) in primary septo-hippocampal cell cultures. Rat NGF cDNA was subcloned into a pUC19-based plasmid containing a CMV promoter. Two days after NGF gene transfection in primary cell cultures, ELISA confirmed increases in NGF protein secretion from transfected cells. To study the biological effect of cationic lipid-mediated NGF gene transfection, we analyzed the amount of neurofilament protein from NGF-transfected cell cultures. Western blot and immunohistochemical analyses detected significant increases in the phosphorylated form of neurofilament proteins in the cultures after cationic lipid-mediated NGF cDNA transfection. Cationic lipid-mediated NGF cDNA transfection did rot cause significant changes in the total amount of neurofilament protein. Our studies suggest that cationic lipid-mediated NGF gene transfection can increase neurofilament phosphorylation but not total neurofilament protein.

Animals↗
PubMed2000

Introduction of the human growth hormone gene into the guinea pig mammary gland by in vivo transfection promotes sustained expression of human growth hormone in the milk throughout lactation.

We tested the feasibility of transfecting mammary tissue in vivo with an expression plasmid encoding the human growth hormone (hGH) gene, under the control of the cytomegalovirus promoter. Guinea pig mammary glands were transfected with plasmid DNA infused through the nipple canal and expression was monitored in control and transfected glands by radioimmunoassay of milk samples for hGH. Sustained expression of hGH throughout lactation was attained with a polyion transfection complex shown to be optimal for the transfection of bovine mammary cells, in vitro. However, contrary to expectations, hGH expression was consistently 5- to 10-fold higher when DEAE-dextran was used alone for transfection. Thus polyion complexes which are optimal for the transfection of cells in vitro may not be optimal in vivo. The highest concentrations of hGH in milk were obtained when glands were transfected within 3 days before parturition. This method may have application for studying the biological role or physical properties of recombinant proteins expressed in low quantities, or for investigating the regulation of gene promoters without the need to construct viral vectors or produce transgenic animals.

Animals↗
PubMed2000

High-efficiency gene transfection of macrophages by lipoplexes.

Macrophage transfection studies are crucial for understanding gene regulation and expression. However, gene transfection in macrophages is difficult. We have shown here that macrophages are more resistant to gene transfection compared with other cell types. To further develop an efficient gene delivery system for macrophages, we evaluated various liposomal and non-liposomal agents including LipofectAMINE(R), Lipofectin(R), DOTAP, DEAE-dextran, and the DNA condensing agent protamine sulfate for their ability to promote gene transfection. CMV-luciferase was used as a reporter plasmid. Macrophage transfection was maximal at the DNA:LipofectAMINE:protamine ratio of 1:12:1 microg/ml. The LipofectAMINE formulation showed a 10-12-fold increase in transfection efficiency over DOTAP and a 4-5-fold increase over Lipofectin. This transfection method showed minimal toxicity at the concentrations tested and was at least 20-25-fold superior to the most frequently used DEAE-dextran method for macrophage transfection.

Animals↗
PubMed1997

Transfection enhancement in Bacillus subtilis displays features of a novel DNA repair pathway. I: DNA base and nucleolytic specificity.

Cells of Bacillus subtilis can enter a natural physiological state, termed competence, that is permissive for uptake of DNA from the surrounding medium. In the B. subtilis genetic system, transfection refers to uptake of isolated bacteriophage DNA by competent host cells, followed by intracellular processing that may ultimately lead to productive infection. Previous investigations have shown that transfecting DNA is usually far less infectious (on a molar basis) than is the DNA injected by phage particles; this result is apparently due to inactivating events suffered by transfecting DNA during its metabolism by competent cells. Earlier studies also demonstrated that, in some cases, the infectivity of transfecting DNA can be increased by ultraviolet (UV) irradiation of the competent cells prior to transfection, or by cotransfection of UV-irradiated heterologous DNAs; collectively, these phenomena have been termed transfection enhancement (TE). We propose here that some transfecting B. subtilis phage DNAs are attacked by a novel host DNA repair system, and that TE reflects inhibition of this by a competing substrate in UV-irradiated DNA. In support of this model, we show that UV-DNA cotransfection leads to a reduced rate of intracellular endonucleolytic breakdown of transfecting DNA. We also demonstrate that TE displays marked specificity of a kind frequently observed for repair enzymes. Thus, phages that contain hydroxymethyl uracil (HMU), but not thymine, in their genomes are susceptible to this process. In addition, we show that the photoproduct(s) in UV-irradiated DNA that produces TE by cotransfection is specific, and is not uracil, a pyrimidine dimer, thymine glycol, HMU, or a substrate for the E. coli thymine glycol DNA N-glycosylase. This photoproduct is derivable from thymine or HMU. The implications of these results are discussed.

Bacillus subtilis↗
PubMed1997

Both estradiol and tamoxifen decrease proliferation and invasiveness of cancer cells transfected with a mutated estrogen receptor.

Previous studies have shown that, after wild-type estrogen receptor (ER) transfection in ER-negative breast cancer cells, estradiol but not tamoxifen prevents growth, invasiveness and metastasis of these cells in mice. Because an ER mutation at position 400 converts the triphenylethylene antiestrogen, OH-tamoxifen into a full estrogen agonist, we transfected this mutated form of human ER in an ER-negative rat cancer cell line. This was aimed at inducing an inhibitory, estrogen-like response of tamoxifen in these cells. In two stable ER-positive transfectants, OH-tamoxifen inhibited cell growth and invasiveness in vitro as efficiently as estradiol. The pure antiestrogen, ICI 164,384, was not agonistic alone and antagonized estrogen action. In contrast, the three compounds were ineffective in control mock-transfected cells. When injected into ovariectomized nude mice, ER-negative mock-transfected cells formed tumours which were significantly stimulated by estradiol and inhibited by tamoxifen treatment. This indicates that estradiol and tamoxifen altered the growth of ER-negative tumours via a general effect on the host response. Surprisingly, the hormone responsiveness of ER-positive tumours developed from ER-transfected cells did not significantly differ from that of ER-negative (mock-transfected) tumours. We conclude that transfection of a mutated human estrogen receptor inhibited, through an estrogenic activity of tamoxifen, the growth and invasiveness of these cancer cells in vitro. However, the low expression of ER did not allowed us to obtain the same effect of tamoxifen in vivo.

Animals↗
PubMedDate not supplied

A nonviral DNA delivery system based on surface modified silica-nanoparticles can efficiently transfect cells in vitro.

Diverse polycationic polymers have been used as nonviral transfection agents. Here we report the ability of colloidal silica particles with covalently attached cationic surface modifications to transfect plasmid DNA in vitro and make an attempt to describe the structure of the resulting transfection complexes. In analogy to the terms lipoplex and polyplex, we propose to describe the nanoparticle-DNA complexes by the term "nanoplex". Three batches, Si10E, Si100E, and Si26H, sized between 10 and 100 nm and with zeta potentials ranging from +7 to +31 mV at pH 7.4 were evaluated. The galactosidase expression plasmid DNA pCMVbeta was immobilized on the particle surface and efficiently transfected Cos-1 cells. The transfection activity was accompanied by very low cytotoxicity, with LD(50) values in the milligrams per milliliter range. The most active batch, Si26H, was produced by modification of commercially available silica particles with N-(6-aminohexyl)-3-aminopropyltrimethoxysilane, yielding spherical nanoparticles with a mean diameter of 26 nm and a zeta potential of +31 mV at pH 7.4. Complexes of Si26H and pCMVbeta plasmid DNA formed at w/w ratios of 10 were most effective in promoting transfection of Cos-1 cells in the absence of serum. At this ratio, >90% of the DNA was associated with the particles, yielding nanoplexes with a net negative surface charge. When the transfection medium was supplemented with 10% serum, maximum gene expression was observed at a w/w ratio of 30, at which the resulting particle-DNA complexes possessed a positive surface charge. Transfection was strongly increased in the presence of 100 microM chloroquine in the incubation medium and reached approximately 30% of the efficiency of a 60 kDa polyethylenimine. In contrast to polyethylenimine, no toxicity was observed at the concentrations required. Atomic force microscopy of Si26H-DNA complexes revealed a spaghetti-meatball-like structure. The surface of complexes prepared at a w/w ratio of 30 was dominated by particles half-spheres. Complex sizes correlated well with those determined previously by dynamic light scattering.

Animals↗
PubMed1999

High efficiency gene transfer by multiple transfection protocol.

A high efficiency transfection protocol employing a common polycationic lipid is described. Using LipofectAMINE, a widely used transfection reagent, we transfected 293T cells with a plasmid harboring the beta-galactosidase (beta-gal) gene. The transfection efficiency was determined by direct staining for X-gal. The conventional transfection protocol achieved an efficiency of <40% while our protocol, which employs the repetition of transfection a few times, achieved an efficiency of approximately 80%. Thus, a dramatic increase in transfection efficiency can be obtained by simply repeating transfection with the use of a common polycationic lipid. This method will be useful in many molecular biological experiments.

Animals↗
PubMed2000

Gene gun transfection of human glioma and melanoma cell lines with genes encoding human IL-12 and GM-CSF.

We used particle-mediated gene transfer by a custom-built gene gun to transfect two well-established human glioma (D54MG and U251) and melanoma (SK mel 28 and Ed 141) cell lines, as well as two glioma lines locally established from primary patient tumors (Ed 147 and Ed 149). Using beta-galactosidase as a reporter gene, D54MG, U251, Ed 141 and SK mel 28 showed an average transfection efficiency of 15-40%, whereas Ed 147 and Ed 149 had mean transfection efficiencies of 3% and 5% respectively. Twenty-four hours after transfection with the gene encoding human interleukin-12 (IL-12), ELISA was performed on cell supernatants (mean of n = 12 for each cell line). IL-12 expression was extremely variable between the different cell lines, ranging from 52 to 1,151 pg/10(6) cells/24 h. Results were very similar when cells were exposed to 20,000 rads of gamma irradiation 2 h after transfection. When the cell lines were transfected with human granulocyte-macrophage colony-stimulating factor, 24 h levels were: 13.0 (Ed 147), 17.8 (Ed 149), 18.6 (Ed 141), 27.4 (D54MG) and 27.7 ng/10(6) cells/24h (U251). SK mel 28 produced 88.1 ng/10(6) cells/24 h. We conclude that the gene gun can efficiently transfect a variety of immortalized, well-established and locally-established glioma and melanoma cell lines. High dose gamma irradiation does not adversely affect the expression of the foreign gene (IL-12) at 24 h. Significantly, transfected cell lines show different levels of expression depending on the particular gene/plasmid introduced. Therefore, each cell line has to be assessed individually for the level of expression of each introduced gene.

Cell Line, Transformed↗
PubMed1999

Effects of immunization with tumor cells double transfected with interleukin-2 (IL-2) and interleukin-12 (IL-12) genes on artificial metastasis of colon26 cells in BALB/c mice.

In order to induce tumor specific cytotoxicity, the poorly immunogenic murine colon cancer cell colon26 was transfected with murine IL-2 cDNA and/or IL-12 cDNA and their anti-tumor effects were investigated. Double transfectants produced murine IL-2 and murine IL-12, the same as single transfectants. Intraperitoneal administration of double transfectants inhibited pulmonary metastasis of colon26 inoculated intravenously to a stronger degree than that of single transfectants. Splenocytes from mice administered double transfectants intraperitonealy showed higher cytolytic activity against colon26 than those from mice administered single transfectants, and also showed cytolytic activity against murine B16-BL6 melanoma. In the NK cell-depleted mice, double transfectants inhibited pulmonary metastasis from the control markedly, but could not do completely, the same as in the NK cell-reserved mice. The difference of the metastatic colonies between NK cell-depleted mice and the control was much greater than that between NK cell-depleted mice and NK cell-reserved mice. These results suggested that cytotoxic T lymphocytes might participate in this anti-tumor effect.

Animals↗
PubMed2001

Effects of radiation on Ca2+ signaling in salivary epithelial cell lines transfected with Bcl-2 and Bcl-XL.

The effects of radiation on the Ca2+ signaling system in HSY cells transfected with the Bcl-2 or Bcl-XL gene were studied. Bcl-2 overexpression did not alter carbachol (CCh)-elicited initial increase in cytosolic free Ca2+ concentrations ([Ca2+]i), but Bcl-XL overexpression dramatically reduced this response. Exposure to 10 Gy gamma-ray did not alter basal [Ca2+]i. By contrast, the CCh-stimulated initial [Ca2+]i increase was reduced at 0.5 and 4 h post-irradiation in all cell types and remained decreased at 24 h in wild-type and control-transfected cells, but recovered in Bcl-2- and Bcl-XL-transfectants. The formation of inositol 1,4,5-trisphosphate (IP3) in response to CCh at 4-h post-irradiation was decreased in wild-type and control-transfected cells, but not in Bcl-2 and Bcl-XL transfectants. The capacity of the IP3-sensitive Ca2+ store was significantly reduced by radiation in all cells except Bcl-XL transfectants. Ca2+ influx after stimulation with CCh was suppressed by exposure to radiation in wild-type and control-transfected cells, but not in Bcl-2- and Bcl-XL-transfectants. However, radiation enhanced Ca2+ influx activated by thapsigargin in all cell types. These results suggest that 1) radiation diminishes IP3 formation and Ca2+ release in response to CCh, but potentiates the store-operated Ca2+ influx; and 2) overexpression of Bcl-2 or Bcl-XL partially protects cells from radiation-induced inhibition of Ca2+ signaling.

Adenocarcinoma↗
PubMed2000

Enhancement of transfection by physical concentration of DNA at the cell surface.

Efficient DNA transfection is critical for biological research and new clinical therapies, but the mechanisms responsible for DNA uptake are unknown. Current nonviral transfection methods, empirically designed to maximize DNA complexation and/or membrane fusion, are amenable to enhancement by a variety of chemicals. These chemicals include particulates, lipids, and polymer complexes that optimize DNA complexation/condensation, membrane fusion, endosomal release, or nuclear targeting, which are the presumed barriers to gene delivery. Most chemical enhancements produce a moderate increase in gene delivery and a limited increase in gene expression. As a result, the efficiency of transfection and level of gene expression after nonviral DNA delivery remain low, suggesting the existence of additional unidentified barriers. Here, we tested the hypothesis that DNA transfection efficiency is limited by a simple physical barrier: low DNA concentration at the cell surface. We used dense silica nanoparticles to concentrate DNA-vector (i.e. DNA-transfection reagent) complexes at the surface of cell monolayers; manipulations that increased complex concentration at the cell surface enhanced transfection efficiency by up to 8.5-fold over the best commercially available transfection reagents. We predict that manipulations aimed at optimizing DNA complexation or membrane fusion have a fundamental physical limit; new methods designed to increase transfection efficiency must increase DNA concentration at the target cell surface without adding to the toxicity.

Animals↗
PubMed1998

Generation of metastatic variants by transfection of a rat non-metastatic epithelial cell line with genomic DNA from rat prostatic carcinoma cells.

Prostate cancer is the second leading cause of male death from malignant disease in Europe and in the USA. Failure to prevent or eliminate metastatic dissemination is a fundamental problem underlying the current inadequate treatment of prostate cancer, and novel therapeutic strategies are required if this disease is to be successfully managed. No independent markers are yet available to predict the behaviour of any individual prostate cancer, particularly its potential to metastasize, and there is now an urgent prerequisite to identify and characterize genes specifically involved in determining the metastatic phenotype of prostate cancer cells before any biologically appropriate treatment modality can be devised. To identify DNA sequences that trophically promote the metastatic phenotype, we have established a new transfection assay with which to monitor activity of prostate cancer genomic DNA. Rat prostatic G and AT6.1 cell lines derived from the same original Dunning R3327 rat prostatic carcinoma exhibit, respectively, low- and high-metastatic phenotypes when grown in syngeneic Copenhagen rats. Rat mammary epithelial cell line 'Rama 37' derived originally from Wistar-Furth rats yields benign non-metastasizing adenomas when inoculated subcutaneously into syngeneic animals. In this report, the Rama 37 cell line is successfully used as the recipient cell-line for transfected DNA fragments extracted from rat prostatic carcinoma G and AT6.1 cells. New metastatic variants of Rama 37 cells have been generated. Enzymatically fragmented genomic DNA from rat metastatic prostate carcinoma cell lines was co-transfected together with plasmid pSV2neo into parental Rama 37 cells, followed by culture in the presence of Geneticin-G418 to select for the transfected cells. To enable subsequent identification of metastasis-promoting DNA sequences, the fragmented genomic DNA sequences were covalently attached to specifically engineered linker DNA molecules to flank the genomic DNA before transfection. Thereafter, the resulting transfectants were pooled and inoculated into mammary fat pads of female Wistar-Furth rats. Metastases produced by the transfectant cells in vivo were reestablished from secondary tumours and probed for the presence of the specific synthetic oligonucleotide sequences that flanked, and hence identified, the presence of the transfected DNA. These new metastatic cells are shown to provide a sensitive assay system with which to detect DNA sequences responsible for conveying the metastatic phenotype of prostate cancer when inoculated into syngeneic rats.

Animals↗
PubMed1989

Functional studies of stable L cell transfectants expressing intercellular adhesion molecule 1 [ICAM-1].

High molecular weight DNA isolated from human tonsil was transfected into mouse L cells to produce transfectants expressing the human intercellular adhesion molecule [ICAM-1]. The transfected ICAM-1 molecule was highly expressed on the cell membrane and our studies show that the transfected ICAM-1 molecule was a fully functional adhesion protein. All leucocyte subtypes showed specific binding to the ICAM-1 transfectants, their adhesion being inhibited by Fab1 fragments of W-CAM-1 antibody and LFA-1 MoAb (leucocyte function antigen). B cell lines (RAJI, Nalm1) showed the highest degree of ICAM-1 mediated adhesion. Normal lymphoblasts showed comparable levels of binding whilst normal neutrophils (both resting and activated by (N-formyl-methionyl-leucyl-phenylalanine) fMLP) showed the least ICAM-1-mediated adhesion. Despite a significant level of adhesion to ICAM-1 transfectants shown by T lymphoblasts generated in a two way MLR there was no evidence of cytolysis of ICAM-1 transfectants. These studies demonstrate the potential of ICAM-1 transfectants as tools for analysis of the role of ICAM-1 in lymphoid adhesion.

Animals↗
PubMed1999

Phase I clinical study applying autologous immunological effector cells transfected with the interleukin-2 gene in patients with metastatic renal cancer, colorectal cancer and lymphoma.

Natural killer-like T lymphocytes termed cytokine-induced killer (CIK) cells have been shown to eradicate established tumours in a severe combined immune deficient (SCID) mouse/human lymphoma model. Recently, we demonstrated that CIK cells transfected with cytokine genes possess an improved proliferation rate and a significantly higher cytotoxic activity as compared to non-transfected cells. Here, in a phase I clinical protocol, autologous CIK cells were generated from peripheral blood obtained by leukapheresis in patients with metastatic renal cell carcinoma, colorectal carcinoma and lymphoma. CIK cells were transfected with a plasmid containing the interleukin-2 (IL-2) gene via electroporation. Transfected cells generated IL-2 in the range of 330-1800 pg 10(-6) cells 24 h(-1) with a mean of 836 pg 10(-6) cells 24 h(-1). Ten patients received 1-5 intravenous infusions of IL-2-transfected CIK cells; five infusions with transfected CIK cells were given. In addition, the same patients received five infusions with untransfected CIK cells for control reasons. In three patients, WHO grade 2 fever was observed. Based on polymerase chain reaction of peripheral blood transfected cells could be detected for up to 2 weeks after infusion. There was a significant increase in serum levels of interferon gamma (IFN-gamma), granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor beta (TGF-beta) during treatment. Interestingly, there was also an increase in CD3+ lymphocytes in the blood of patients during therapy. In accordance, a partial increase in cytotoxic activity in peripheral blood lymphocytes (PBLs) was documented when patient samples before and after therapy were compared. Concerning clinical outcome, six patients remained in progressive disease, three patients showed no change by treatment, and one patient with lymphoma developed a complete response. In conclusion, we were able to demonstrate that CIK cells transfected with the IL-2 gene can be administered without major side-effects and are promising for future therapeutic trials.

Adolescent↗