Leishmania (V.) guyanensis: isolation and characterization of glucantime-resistant cell lines

1996 ◽  
Vol 42 (9) ◽  
pp. 944-949 ◽  
Author(s):  
K. C. Ferreira-Pinto ◽  
A. L. Miranda-Vilela ◽  
C. Anacleto ◽  
A. P. S. M. Fernandes ◽  
M. C. B. Abdo ◽  
...  
Keyword(s):  
Cell Lines ◽  
Blot Hybridization ◽  
Resistant Cell ◽  
Cross Resistance ◽  
Isolation And Characterization ◽  
Stability Of Resistance ◽  
One Step ◽  
The Stability ◽  
The One

A glucantime sensitive Leishmania (V.) guyanensis strain was used to obtain in vitro resistant cell lines, by increments in glucantime concentrations employing both one step and stepwise protocols. Whereas the effective concentration of drug that inhibited the growth of wild type cells by 50% (EC50 value) was 0.20 mg Sbv/mL, the resistant cells were able to grow in glucantime concentrations greater than 8.0 mg/mL. The resistant cell lines were partially characterized by their in vitro response to glucantime, the stability of resistance phenotype, cross resistance to a range of drugs, and also by the analysis of total DNA fragments generated by restriction endonucleases and blot hybridization. Amplified DNA sequence similar to a P-glycoprotein analog from Leishmania tarentolae (ltpgpA gene) was observed in all the resistant cell lines obtained through the one-step protocol. These cell lines showed cross resistance to heavy metals but were sensitive to puromycin, vinblastine, and pentostam.Key words: Leishmania, glucantime resistance, pentavalent antimony, gene amplification.

Isolation and characterization of Drosophila multidrug resistance gene homologs

1991 ◽  
Vol 11 (8) ◽  
pp. 3940-3948
Author(s):  
C T Wu ◽  
M Budding ◽  
M S Griffin ◽  
J M Croop
Keyword(s):  
Amino Acid ◽  
Cell Lines ◽  
Multidrug Resistant ◽  
Amino Acid Identity ◽  
Resistant Cell ◽  
Cross Resistance ◽  
Multidrug Resistance Gene ◽  
Isolation And Characterization ◽  
P Glycoprotein

Mammalian multidrug-resistant cell lines, selected for resistance to a single cytotoxic agent, display cross-resistance to a broad spectrum of structurally and functionally unrelated compounds. These cell lines overproduce a membrane protein, the P-glycoprotein, which is encoded by a member(s) of a multigene family, termed mdr or pgp. The amino acid sequence of the P-glycoprotein predicts an energy-dependent transport protein with homology to a large superfamily of proteins which transport a wide variety of substances. This report describes the isolation and characterization of two Drosophila homologs of the mammalian mdr gene. These homologs, located in chromosomal sections 49EF and 65A, encode proteins that share over 40% amino acid identity to the human and murine mdr P-glycoproteins. Fly strains bearing disruptions in the homolog in section 49EF have been constructed and implicate this gene in conferring colchicine resistance to the organism. This work sets the foundation for the molecular and genetic analysis of mdr homologs in Drosophila melanogaster.

Isolation and preliminary characterization of ACNUresistant sublines of rat brain tumors in vivo

1992 ◽  
Vol 77 (3) ◽  
pp. 451-456 ◽  
Author(s):  
T. Ken Yoshida ◽  
Keiji Shimizu ◽  
Athanasios Koulousakis ◽  
Volker Sturm ◽  
Emile Beuls
Keyword(s):  
Brain Tumors ◽  
Rat Brain ◽  
Cell Lines ◽  
Resistant Cell ◽  
Chemotherapeutic Agents ◽  
Cross Resistance ◽  
Chemical Structures ◽  
Wide Range

✓ Two variant cells lines resistant to the nitrosourea derivative ACNU ((1-4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride), namely C6/ACNU and 9L/ACNU, were selected in vivo from rat brain tumors. Stable resistance to ACNU proved to be a characteristic of these cell lines, whether they were grown in vivo or in vitro. These cell lines exhibited a different pattern of cross-resistance to a wide range of chemotherapeutic agents with dissimilar chemical structures and mechanisms of action as compared with that of other ACNU-resistant cell lines established in vitro. Distinct cross-resistance was observed in both the C6/ACNU and 9L/ACNU cell lines to chloroethyl-nitrosoureas such as BCNU (carmustine), CCNU (lomustine), and methyl CCNU and, additionally, to vincristine, vinblastine, Adriamycin (doxorubicin), and arabinosylcytosine, but not to bleomycin, methotrexate, c/s-platinum, and 5-fluorouracil. This might point to a multifactorial mechanism of drug resistance in ACNU-resistant cell lines derived from rat C6 and 9L brain tumor cells.

scholarly journals Isolation and characterization of Drosophila multidrug resistance gene homologs.

1991 ◽  
Vol 11 (8) ◽  
pp. 3940-3948 ◽  
Author(s):  
C T Wu ◽  
M Budding ◽  
M S Griffin ◽  
J M Croop
Keyword(s):  
Amino Acid ◽  
Cell Lines ◽  
Multidrug Resistant ◽  
Amino Acid Identity ◽  
Resistant Cell ◽  
Cross Resistance ◽  
Multidrug Resistance Gene ◽  
Isolation And Characterization ◽  
P Glycoprotein

Mammalian multidrug-resistant cell lines, selected for resistance to a single cytotoxic agent, display cross-resistance to a broad spectrum of structurally and functionally unrelated compounds. These cell lines overproduce a membrane protein, the P-glycoprotein, which is encoded by a member(s) of a multigene family, termed mdr or pgp. The amino acid sequence of the P-glycoprotein predicts an energy-dependent transport protein with homology to a large superfamily of proteins which transport a wide variety of substances. This report describes the isolation and characterization of two Drosophila homologs of the mammalian mdr gene. These homologs, located in chromosomal sections 49EF and 65A, encode proteins that share over 40% amino acid identity to the human and murine mdr P-glycoproteins. Fly strains bearing disruptions in the homolog in section 49EF have been constructed and implicate this gene in conferring colchicine resistance to the organism. This work sets the foundation for the molecular and genetic analysis of mdr homologs in Drosophila melanogaster.

scholarly journals Efficient Cryopreservation of Populus tremula by In Vitro-Grown Axillary Buds and Genetic Stability of Recovered Plants

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 77
Author(s):  
Elena O. Vidyagina ◽  
Nikolay N. Kharchenko ◽  
Konstantin A. Shestibratov
Keyword(s):  
Survival Rate ◽  
Axillary Buds ◽  
Long Term Storage ◽  
Average Survival ◽  
Transgenic Lines ◽  
Ssr Loci ◽  
One Step ◽  
The One

Axillary buds of in vitro microshoots were successfully frozen at –196 °C by the one-step freezing method using the protective vitrification solution 2 (PVS2). Microshoots were taken from 11 transgenic lines and three wild type lines. Influence of different explant pretreatments were analyzed from the point of their influence towards recovery after cryopreservation. It was found out that the use of axillary buds as explants after removal of the apical one increases recovery on average by 8%. The cultivation on growth medium of higher density insignificantly raises the regenerants survival rate. Pretreatment of the osmotic fluid (OF) shows the greatest influence on the survival rate. It leads to the increase in survival rate by 20%. The cryopreservation technology providing regenerants average survival rate of 83% was developed. It was based on the experimental results obtained with explant pretreatment. Incubation time in liquid nitrogen did not affect the explants survival rate after thawing. After six months cryostorage of samples their genetic variability was analyzed. Six variable simple sequence repeat (SSR) loci were used to analyze genotype variability after the freezing-thawing procedure. The microsatellite analysis showed the genetic status identity of plants after cryopreservation and of the original genotypes. The presence of the recombinant gene in the transgenic lines after cryostorage were confirmed so as the interclonal variation in the growth rate under greenhouse conditions. The developed technique is recommended for long-term storage of various breeding and genetically modified lines of aspen plants, as it provides a high percentage of explants survival with no changes in genotype.

Bortezomib blocks Bax degradation in malignant B cells during treatment with TRAIL

Blood ◽  
2008 ◽  
Vol 111 (5) ◽  
pp. 2797-2805 ◽  
Author(s):  
Feng-Ting Liu ◽  
Samir G. Agrawal ◽  
John G. Gribben ◽  
Hongtao Ye ◽  
Ming-Qing Du ◽  
...  
Keyword(s):  
B Cells ◽  
Cell Lines ◽  
Proteasome Inhibitor ◽  
Resistant Cell ◽  
Protein Levels ◽  
Bax Protein ◽  
Degradation Activity ◽  
Potent Drug ◽  
Induced Apoptosis

Proapoptotic Bcl-2 family member Bax is a crucial protein in the induction of apoptosis, and its activation is required for this process. Here we report that Bax is a short-lived protein in malignant B cells and Bax protein levels decreased rapidly when protein synthesis was blocked. Malignant B cells were relatively resistant to tumor necrosis factor–related apoptosis inducing ligand (TRAIL)–induced apoptosis, and this correlated with low basal Bax protein levels. Furthermore, during treatment with TRAIL, the resistant cell lines showed prominent Bax degradation activity. This degradation activity was localized to mitochondrial Bax and could be prevented by truncated Bid, a BH3-only protein; in contrast, cytosolic Bax was relatively stable. The proteasome inhibitor bortezomib is a potent drug in inducing apoptosis in vitro in malignant B-cell lines and primary chronic lymphocytic leukemic (CLL) cells. In CLL cells, bortezomib induced Bax accumulation, translocation to mitochondria, conformational change, and oligomerization. Accumulation and stabilization of Bax protein by bortezomib-sensitized malignant B cells to TRAIL-induced apoptosis. This study reveals that Bax instability confers resistance to TRAIL, which can be reversed by Bax stabilization with a proteasome inhibitor.

cis-Dichloroplatinum(II) complexes tethered to 9-aminoacridine-4-carboxamides: synthesis and action in resistant cell lines in vitro

2001 ◽  
Vol 85 (2-3) ◽  
pp. 209-217 ◽  
Author(s):  
Rodney J Holmes ◽  
Mark J McKeage ◽  
Vincent Murray ◽  
William A Denny ◽  
W.David McFadyen
Keyword(s):  
Cell Lines ◽  
Resistant Cell

Influence of amide versus ester linkages on the anticancer properties of the new flavone–biotin conjugates

2019 ◽  
Vol 74 (7-8) ◽  
pp. 193-200
Author(s):  
Monika Stompor ◽  
Marta Świtalska ◽  
Agata Bajek ◽  
Joanna Wietrzyk
Keyword(s):  
Cell Lines ◽  
Amide Bond ◽  
Step Method ◽  
Fluorescent Reporter ◽  
Bifunctional Molecules ◽  
Anticancer Properties ◽  
One Step ◽  
3T3 Cell Lines ◽  
Mcf 7

Abstract Novel biotinylated C-6 substituted flavones were synthesised by a one-step method that connects biotin to 6-hydroxyflavone and 6-aminoflavone by esterification and amidation of hydroxyl and amino groups, respectively. The obtained compounds, 6-O-biotinylflavone and 6-biotinylamidoflavone, are the bifunctional molecules composed of a flavone moiety as a fluorescent reporter and biotin as a cancer-targeting unit. Antiproliferative activity was evaluated using SRB assays in MCF-7, MCF-10A, HepG2, MDA-MB-231, 4T1, and Balb/3T3 cell lines. In vitro evaluation revealed that compounds with biotin moiety displayed better cell selectivity between the cancer and normal cells than the parental substrates. These results indicate that anticancer effect is not related to the position of biotin moiety, but it is related to the presence of ester or amide bond. 6-O-Biotinylflavone was more active than 6-hydroxyflavone against human breast (MDA-MB-231) and liver (HepG2) cancer cells with IC50 (concentration of tested agent that inhibits proliferation of the cell population by 50%) values equal to 78.5 ± 18.8 μM and 133.2 ± 14.2 μM, respectively. Non biotinylated 6-aminoflavone was more active than 6-biotinylamidoflavone against all tested cell lines, with IC50 values between 34.3 ± 9.1 μM (4T1) and 173.86 ± 24.3 μM (MCF-7).

171 Effect of progesterone and prolactin on the developmental competence of bovine oocytes during the terminal phase of in vitro maturation

2019 ◽  
Vol 31 (1) ◽  
pp. 210
Author(s):  
G. Singina ◽  
E. Shedova ◽  
T. Taradajnic ◽  
V. Konnova ◽  
E. Tsyndrina
Keyword(s):  
Cell Number ◽  
Total Cell ◽  
Developmental Competence ◽  
Terminal Phase ◽  
Cleavage Rate ◽  
Total Cell Number ◽  
One Step ◽  
Group 2 ◽  
The One

To date, considerable progress has been achieved in in vitro production (IVP) technologies in cattle; however, developmental potentials of oocytes matured in vitro remain low compared with in vivo-matured oocytes. Thus, a better understanding of different aspects of oocyte maturation may allow us to increase the embryo development rate. Our study was aimed to assess the effects of progesterone (P4) and prolactin (PRL) on the bovine oocyte developmental competence. Bovine cumulus-enclosed oocytes (CEO) were matured using either one-step or two-step maturation conditions. For the one-step protocol, CEO were cultured for 24h in TCM-199 supplemented with 10% fetal calf serum (FCS), 10μg mL−1 porcine FSH, and 10μg mL−1 ovine LH (standard medium). For the two-step procedure, CEO were first cultured for 16h in the standard medium (n=1263) and then transferred to 1 of 3 experimental media and cultured for additional 8h in either absence or presence of either P4 (50 ng mL−1) or bovine PRL (50ng mL−1). The 3 media tested in the two-step maturation were (1) TCM-199 containing 10% FCS (group 1), (2) TCM-199 containing 3mg mL−1 BSA (group 2), or (3) Fert-TALP medium supplemented with 6mg mL−1 BSA (group 3). Fert-TALP was selected because it can potentially be used throughout maturation and fertilization. Following in vitro maturation, all oocytes underwent an IVF/in vitro culture procedure as described previously (Singina et al. 2014 Reprod. Fertil. Devel. 26, 154). The embryo development was evaluated at Days 2 and 7 for cleavage and blastocyst rates. In addition, obtained blastocysts were fixed, and the total cell number and the level of apoptosis were determined using 4′,6-diamidino-2-phenylindole (DAPI) and TUNEL staining. The data from 4 to 5 replicates (113-159 oocytes per treatment) were analysed by ANOVA. For oocytes matured for 24h in the one-step culture, the cleavage rate, blastocyst rate, total cell number, and apoptotic nuclei per blastocyst were 66.1±1.1, 23.7±2.0, 71.4±9.1, and 4.8±1.2%, respectively. For the two-step culture, the cleavage rate did not differ from that of the one-step culture system, ranging from 64.8 to 76.5%. Also, no effects of the two-step systems were observed on total cell number (63.0-78.8) or the proportion of apoptotic nuclei (3.3-5.3%) at the blastocyst stage. The culture of CEO in group 1 (without the supplements) had a reduced blastocyst rate (17.4±0.4%; P<0.05) compared with the standard one-step maturation group, and the addition of P4 (but not PRL) improved the blastocyst yield (P<0.05). Furthermore, when P4 (but not PRL) was added to group 2 and group 3 media, blastocyst rates increased significantly (32.9±3.1 and 32.8±2.7%, respectively) compared with those of the one-step group (P<0.05), but did not differ from those of untreated groups 2 and 3 (26.2±2.7 and 30.0±3.0%, respectively). Our data indicate that P4 supplementation during the terminal phase of two-step IVM can enhance the developmental competence of bovine oocytes and that the nature of this effect depends on the composition of IVM medium, whereas no effect of PRL supplementation was observed. The study was supported by RFBR (No. 17-29-08035).

scholarly journals Upregulation of KCNQ1OT1 promotes resistance to stereotactic body radiotherapy in lung adenocarcinoma by inducing ATG5/ATG12-mediated autophagy via miR-372-3p

2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Huanyu He ◽  
Xinmao Song ◽  
Zuozhang Yang ◽  
Yuchi Mao ◽  
Kunming Zhang ◽  
...  
Keyword(s):  
Cell Lines ◽  
Stereotactic Body Radiotherapy ◽  
Clinical Stage ◽  
Resistant Cell ◽  
Antitumor Effects ◽  
Large Tumor ◽  
Advanced Clinical Stage ◽  
Potential Strategy

Abstract Stereotactic body radiotherapy (SBRT) has emerged as a standard treatment for non-small-cell lung cancer. However, its therapeutic advantages are limited with the development of SBRT resistance. The SBRT-resistant cell lines (A549/IR and H1975/IR) were established after exposure with hypofractionated irradiation. The differential lncRNAs were screened by microarray assay, then the expression was detected in LUAD tumor tissues and cell lines by qPCR. The influence on radiation response was assessed via in vitro and in vivo assays, and autophagy levels were evaluated by western blot and transmission electron microscopy. Bioinformatics prediction and rescue experiments were used to identify the pathways underlying SBRT resistance. High expression of KCNQ1OT1 was identified in LUAD SBRT-resistant cells and tissues, positively associated with a large tumor, advanced clinical stage, and a lower response rate to concurrent therapy. KCNQ1OT1 depletion significantly resensitized A549/IR and H1975/IR cells to radiation by inhibiting autophagy, which could be attenuated by miR-372-3p knockdown. Furthermore, autophagy-related 5 (ATG5) and autophagy-related 12 (ATG12) were confirmed as direct targets of miR-372-3p. Restoration of either ATG5 or ATG12 abrogated miR-372-3p-mediated autophagy inhibition and radiosensitivity. Our data describe that KCNQ1OT1 is responsible for SBRT resistance in LUAD through induction of ATG5- and ATG12-dependent autophagy via sponging miR-372-3p, which would be a potential strategy to enhance the antitumor effects of radiotherapy in LUAD.

scholarly journals Dissecting Mechanisms of Melanoma Resistance to BRAF and MEK Inhibitors Revealed Genetic and Non-Genetic Patient- and Drug-Specific Alterations and Remarkable Phenotypic Plasticity

Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 142 ◽  
Author(s):  
Mariusz L. Hartman ◽  
Malgorzata Sztiller-Sikorska ◽  
Anna Gajos-Michniewicz ◽  
Malgorzata Czyz
Keyword(s):  
Phenotypic Plasticity ◽  
Cell Lines ◽  
Mapk Pathway ◽  
Acquired Resistance ◽  
Resistance Mechanisms ◽  
Genetic Alterations ◽  
Resistant Cell ◽  
Cross Resistance ◽  
Preclinical Model ◽  
Development Of Resistance

The clinical benefit of MAPK pathway inhibition in BRAF-mutant melanoma patients is limited by the development of acquired resistance. Using drug-naïve cell lines derived from tumor specimens, we established a preclinical model of melanoma resistance to vemurafenib or trametinib to provide insight into resistance mechanisms. Dissecting the mechanisms accompanying the development of resistance, we have shown that (i) most of genetic and non-genetic alterations are triggered in a cell line- and/or drug-specific manner; (ii) several changes previously assigned to the development of resistance are induced as the immediate response to the extent measurable at the bulk levels; (iii) reprogramming observed in cross-resistance experiments and growth factor-dependence restricted by the drug presence indicate that phenotypic plasticity of melanoma cells largely contributes to the sustained resistance. Whole-exome sequencing revealed novel genetic alterations, including a frameshift variant of RBMX found exclusively in phospho-AKThigh resistant cell lines. There was no similar pattern of phenotypic alterations among eleven resistant cell lines, including expression/activity of crucial regulators, such as MITF, AXL, SOX, and NGFR, which suggests that patient-to-patient variability is richer and more nuanced than previously described. This diversity should be considered during the development of new strategies to circumvent the acquired resistance to targeted therapies.

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