scholarly journals Chitosan-Based Polyelectrolyte Complexes for Doxorubicin and Zoledronic Acid Combined Therapy to Overcome Multidrug Resistance

Pharmaceutics ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 180 ◽  
Author(s):  
Simona Giarra ◽  
Silvia Zappavigna ◽  
Virginia Campani ◽  
Marianna Abate ◽  
Alessia Cossu ◽  
...  
Keyword(s):  
Zoledronic Acid ◽  
Cell Lines ◽  
Combined Therapy ◽  
Polymer Concentration ◽  
Resistant Cell ◽  
Wild Type ◽  
Polyelectrolyte Complexes ◽  
Ionotropic Gelation ◽  
Experimental Parameters

This study aimed to develop nanovectors co-encapsulating doxorubicin (Doxo) and zoledronic acid (Zol) for a combined therapy against Doxo-resistant tumors. Chitosan (CHI)-based polyelectrolyte complexes (PECs) prepared by ionotropic gelation technique were proposed. The influence of some experimental parameters was evaluated in order to optimize the PECs in terms of size and polydispersity index (PI). PEC stability was studied by monitoring size and zeta potential over time. In vitro studies were carried out on wild-type and Doxo-resistant cell lines, to assess both the synergism between Doxo and Zol, as well as the restoring of Doxo sensitivity. Polymer concentration, incubation time, and use of a surfactant were found to be crucial to achieving small size and monodisperse PECs. Doxo and Zol, only when encapsulated in PECs, showed a synergistic antiproliferative effect in all the tested cell lines. Importantly, the incubation of Doxo-resistant cell lines with Doxo/Zol co-encapsulating PECs resulted in the restoration of Doxo sensitivity.

scholarly journals A phospho-proteomic study of cetuximab resistance in KRAS/NRAS/BRAFV600 wild-type colorectal cancer

2021 ◽  
Author(s):  
Alexandros Georgiou ◽  
Adam Stewart ◽  
Georgios Vlachogiannis ◽  
Lisa Pickard ◽  
Nicola Valeri ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Signal Transduction ◽  
Drug Resistance ◽  
Cell Lines ◽  
Ex Vivo ◽  
Pi3k Pathway ◽  
Resistant Cell ◽  
Wild Type ◽  
Proteomic Study

Abstract Purpose We hypothesised that plasticity in signal transduction may be a mechanism of drug resistance and tested this hypothesis in the setting of cetuximab resistance in patients with KRAS/NRAS/BRAFV600 wild-type colorectal cancer (CRC). Methods A multiplex antibody-based platform was used to study simultaneous changes in signal transduction of 55 phospho-proteins in 12 KRAS/NRAS/BRAFV600 wild-type CRC cell lines (6 cetuximab sensitive versus 6 cetuximab resistant) following 1 and 4 h in vitro cetuximab exposure. We validated our results in CRC patient samples (n = 4) using ex vivo exposure to cetuximab in KRAS/NRAS/BRAFV600 cells that were immunomagnetically separated from the serous effusions of patients with known cetuximab resistance. Results Differences in levels of phospho-proteins in cetuximab sensitive and resistant cell lines included reductions in phospho-RPS6 and phospho-PRAS40 in cetuximab sensitive, but not cetuximab resistant cell lines at 1 and 4 h, respectively. In addition, phospho-AKT levels were found to be elevated in 3/4 patient samples following ex vivo incubation with cetuximab for 1 h. We further explored these findings by studying the effects of combinations of cetuximab and two PI3K pathway inhibitors in 3 cetuximab resistant cell lines. The addition of PI3K pathway inhibitors to cetuximab led to a significantly higher reduction in colony formation capacity compared to cetuximab alone. Conclusion Our findings suggest activation of the PI3K pathway as a mechanism of cetuximab resistance in KRAS/NRAS/BRAFV600 wild-type CRC.

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

scholarly journals Inhibition of MUS81 By siRNA Reverses Resistance to Cisplatin in Human Ovarian Cancer Cell Lines

2021 ◽  
Author(s):  
Emma C. Bourton ◽  
Sheba Adam-Zahir ◽  
Piers N. Plowman ◽  
Hussein Nahidh Al-Ali ◽  
Helen A. Foster ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Protein Expression ◽  
Cell Lines ◽  
Cancer Cell ◽  
Ovarian Cancer Cell ◽  
Cancer Cell Lines ◽  
Resistant Cell ◽  
Wild Type ◽  
Ovarian Cancer Cell Lines ◽  
Sirna Knockdown

Abstract Bacground: Drugs that induce DNA interstrand crosslinks form the mainstay of anticancer treatments for different cancers. These drugs are used to treat ovarian cancer which is the most prevalent gynaecological cancer. Five-year survival rates are approximately 40% and the development of drug resistant disease is an important factor in treatment failure. Methods: In this study a comprehensive evaluation of the expression and function of the site-specific endonuclease MUS81 was conducted. Using quantitative real time PCR analysis and imaging flow cytometry we determined the mRNA and protein expression of MUS81 in three ovarian cancer cell lines and two immortalised human fibroblast cell lines which had been made resistant to cisplatin by chronic exposure. siRNA knockdown of MUS81 was employed to determine the effect on overall cell survival which was assessed using clonogenic assays. Results: In the five cisplatin-resistant cell lines we observed increased MUS81 mRNA expression. In addition MUS81 protein expression in the form of discrete nuclear foci in cells was observed in all cell lines following cisplatin exposure, there being significantly more foci in cisplatin resistant cell lines. siRNA knockdown of MUS81 significantly reduced both mRNA and protein levels in two cell lines (SK-OV-3 and MRC5-SV1 – wild-type and resistant) and critically re-sensitised cisplatin resistant cells to wild-type level, determined by clonogenic assay.Conclusion: MUS81 is central to the development of cisplatin resistance in ovarian cancer cell lines. Inhibition of MUS81 restored drug sensitivity to the cells. MUS81 may be a useful therapeutic target to overcome drug resistance in ovarian and other cancers.

scholarly journals Atorvastatin enhances the antitumor activity of tamoxifen in B16f10 mouse melanoma cell lines

2020 ◽  
Vol 25 (1) ◽  
pp. 83-91
Author(s):  
Maryam Malek ◽  
◽  
Maedeh Ghasemi ◽  
Golnaz Vaseghi ◽  
Ahmad Ghasemi ◽  
...  
Keyword(s):  
Cell Lines ◽  
Melanoma Cell ◽  
Mevalonate Pathway ◽  
Combined Therapy ◽  
Metastatic Malignant Melanoma ◽  
Mouse Melanoma ◽  
Melanoma Cancer ◽  
Mouse Melanoma Cell ◽  
Melanoma Cell Lines

Introduction: Tamoxifen has been used in the treatment of metastatic malignant melanoma more common with other agents in the combined therapy. Up-regulated activity of the mevalonate pathway has been shown in a range of different cancers. Atorvastatin is the most commonly used statin approved for cholesterol reduction by inhibiting the mevalonate pathway and has been shown to inhibit tumor growth. In the present study, we used atorvastatin and tamoxifen combination therapy on B16f10 mouse melanoma cell lines to study whether atorvastatin could increase the sensitivity of melanoma cells to the chemotherapeutic agent such as tamoxifen. Methods: The cell line was treated with different concentrations of tamoxifen and/or atorvastatin for 24 and 48h and the effects of treatment on p53 and RhoA were investigated using quantitative RT-PCR. Results: The combination of atorvastatin and tamoxifen resulted in a potentiation antitumor effect via up-regulation of p53 and down-regulation of RhoA expression against melanoma tumors in vitro. Furthermore, we demonstrated the combination of atorvastatin with tamoxifen could reduce tamoxifen dose to minimize possible detrimental side effects in melanoma. Conclusion: Our results suggested that atorvastatin as a combined therapy with tamoxifen may provide a new approach for improving the efficacy and treating against melanoma cancer but needs further exploration in clinical trials.

Chromosome-mediated gene transfer of hydroxyurea resistance and amplification of ribonucleotide reductase activity

1983 ◽  
Vol 3 (6) ◽  
pp. 1053-1061
Author(s):  
W H Lewis ◽  
P R Srinivasan
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Ribonucleotide Reductase ◽  
Chinese Hamster ◽  
Fold Increase ◽  
Resistant Cell ◽  
Plating Efficiency ◽  
Wild Type Cell ◽  
Wild Type ◽  
Metaphase Chromosomes

Metaphase chromosomes purified from a hydroxyurea-resistant Chinese hamster cell line were able to transform recipient wild-type cells to hydroxyurea resistance at a frequency of 10(-6). Approximately 60% of the resulting transformant clones gradually lost hydroxyurea resistance when cultivated for prolonged periods in the absence of drug. One transformant was subjected to serial selection in higher concentrations of hydroxyurea. The five cell lines generated exhibited increasing relative plating efficiency in the presence of the drug and a corresponding elevation in their cellular content of ribonucleotide reductase. The most resistant cell line had a 163-fold increase in relative plating efficiency and a 120-fold increase in enzyme activity when compared with the wild-type cell line. The highly hydroxyurea-resistant cell lines had strong electron paramagnetic resonance signals characteristic of an elevated level of the free radical present in the M2 subunit of ribonucleotide reductase. Two-dimensional electrophoresis of cell-free extracts from one of the resistant cell lines indicated that a 53,000-dalton protein was present in greatly elevated quantities when compared with the wild-type cell line. These data suggest that the hydroxyurea-resistant cell lines may contain an amplification of the gene for the M2 subunit of ribonucleotide reductase.

Abstract 470: Recording Cell Migration Dynamics in Mouse Tissues With Cells Secreting Fluorescence Protein-tagged Collagen

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Zhongming Chen
Keyword(s):  
Cell Migration ◽  
Cell Lines ◽  
Wild Type Mouse ◽  
Cardiac Progenitor Cells ◽  
Wild Type ◽  
Mouse Tissues ◽  
Migration Dynamics ◽  
Fluorescence Protein

Background: Cell migration is an important step involved in heart regeneration and many cardiovascular diseases. However, cell migration dynamics in vivo is poorly understood due to the challenges from mammal hearts, which are opaque and fast beating, and thus individual cardiac cells cannot be imaged or tracked. Aims: In this study, cell migration dynamics in the heart is recorded with a novel strategy, in which fluorescence protein-tagged collagen is secreted from cells and deposited into extracellular matrix, forming visible trails when cells are moving in tissues. As a proof-of-concept, transplanted migration dynamics of cardiac progenitor cells in mouse hearts were investaged. Methods: Stable cell lines expressing mCherry-tagged type I collagen were generated from isolated cardiac progenitor cells, ABCG2 + CD45 - CD31 - cells (side populations), or c-kit + CD45 - CD31 - cells (c-kit + CPCs). The cell migration dynamics were monitored and measured based on the cell trails after cell transplantation into mouse tissues. Results: The stable cell lines form red cell trails both in vitro and in vivo (Fig. 1A & 1B, Green: GFP; Red: mCherry-collagen I, Blue: DAPI, bar: 50 microns). In culture dishes, the cells form visible cell trails of fluorescence protein. The cell moving directions are random, with a speed of 288 +/- 79 microns/day (side populations, n=3) or 143 +/-37 microns/day (c-kit + CPCs, n=3). After transplantation into wild-type mouse hearts, the cells form highly tortuous trails along the gaps between the heart muscle fibers. Angle between a cell trail and a muscle fiber is 16+/-16 degree (n=3). Side populations migrate twice as fast as c-kit+ CPCs in the heart (16.0 +/-8.7 microns/day vs. 8.1+/-0.0 microns/day, n=3, respectively), 18 time slower than the respective speeds in vitro . Additionally, side populations migrate significantly faster in the heart than in the skeletal muscles (26.4+/-5.8 microns/day, n=3). The side populations move significantly faster in immunodeficient mouse hearts (36.7+/-13.3 microns/day, n=3, typically used for studying cell therapies) than in wild-type mouse hearts. Conclusion: For the first time, cell migration dynamics in living hearts is monitored and examined with genetically modified cell lines. This study may greatly advance the fields of cardiovascular biology.

scholarly journals Serotonin 5-HT2C Receptor Cys23Ser Single Nucleotide Polymorphism Associates with Receptor Function and Localization In Vitro

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Michelle A. Land ◽  
Holly L. Chapman ◽  
Brionna D. Davis-Reyes ◽  
Daniel E. Felsing ◽  
John A. Allen ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Subcellular Localization ◽  
Cell Lines ◽  
Intracellular Signaling ◽  
Calcium Release ◽  
Wild Type ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Recycling Pathway

Abstract A non-synonymous single nucleotide polymorphism of the human serotonin 5-HT2C receptor (5-HT2CR) gene that converts a cysteine to a serine at amino acid codon 23 (Cys23Ser) appears to impact 5-HT2CR pharmacology at a cellular and systems level. We hypothesized that the Cys23Ser alters 5-HT2CR intracellular signaling via changes in subcellular localization in vitro. Using cell lines stably expressing the wild-type Cys23 or the Ser23 variant, we show that 5-HT evokes intracellular calcium release with decreased potency and peak response in the Ser23 versus the Cys23 cell lines. Biochemical analyses demonstrated lower Ser23 5-HT2CR plasma membrane localization versus the Cys23 5-HT2CR. Subcellular localization studies demonstrated O-linked glycosylation of the Ser23 variant, but not the wild-type Cys23, may be a post-translational mechanism which alters its localization within the Golgi apparatus. Further, both the Cys23 and Ser23 5-HT2CR are present in the recycling pathway with the Ser23 variant having decreased colocalization with the early endosome versus the Cys23 allele. Agonism of the 5-HT2CR causes the Ser23 variant to exit the recycling pathway with no effect on the Cys23 allele. Taken together, the Ser23 variant exhibits a distinct pharmacological and subcellular localization profile versus the wild-type Cys23 allele, which could impact aspects of receptor pharmacology in individuals expressing the Cys23Ser SNP.

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 Unstable Spinocerebellar Ataxia Type 10 (ATTCT)·(AGAAT) Repeats Are Associated with Aberrant Replication at the ATX10 Locus and Replication Origin-Dependent Expansion at an Ectopic Site in Human Cells

2007 ◽  
Vol 27 (22) ◽  
pp. 7828-7838 ◽  
Author(s):  
Guoqi Liu ◽  
John J. Bissler ◽  
Richard R. Sinden ◽  
Michael Leffak
Keyword(s):  
Molecular Mechanism ◽  
Cell Lines ◽  
Spinocerebellar Ataxia ◽  
Replication Origin ◽  
Spinocerebellar Ataxia Type ◽  
Dna Unwinding ◽  
Wild Type ◽  
Normal Length ◽  
Population Doublings

ABSTRACT Spinocerebellar ataxia type 10 (SCA10) is associated with expansion of (ATTCT) n repeats (where n is the number of repeats) within the ataxin 10 (ATX10/E46L) gene. The demonstration that (ATTCT) n tracts can act as DNA unwinding elements (DUEs) in vitro has suggested that aberrant replication origin activity occurs at expanded (ATTCT) n tracts and may lead to their instability. Here, we confirm these predictions. The wild-type ATX10 locus displays inefficient origin activity, but origin activity is elevated at the expanded ATX10 loci in patient-derived cells. To test whether (ATTCT) n tracts can potentiate origin activity, cell lines were constructed that contain ectopic copies of the c-myc replicator in which the essential DUE was replaced by ATX10 DUEs with (ATTCT) n . ATX10 DUEs containing (ATTCT)27 or (ATTCT)48, but not (ATTCT)8 or (ATTCT)13, could substitute functionally for the c-myc DUE, but (ATTCT)48 could not act as an autonomous replicator. Significantly, chimeric c-myc replicators containing ATX10 DUEs displayed length-dependent (ATTCT) n instability. By 250 population doublings, dramatic two- and fourfold length expansions were observed for (ATTCT)27 and (ATTCT)48 but not for (ATTCT)8 or (ATTCT)13. These results implicate replication origin activity as one molecular mechanism associated with the instability of (ATTCT) n tracts that are longer than normal length.

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