Detection of the 170 kDa P-Glycoprotein in Neoplastic and Normal Tissues

1989 ◽  
Vol 75 (6) ◽  
pp. 542-546 ◽  
Author(s):  
Enrico Ronchi ◽  
Ornella Sanfilippo ◽  
Giovanni Di Fronzo ◽  
Maria Rosa Bani ◽  
Gabriella Della Torre ◽  
...  
Keyword(s):  
Protein A ◽  
Resistant Cell ◽  
Nodal Metastasis ◽  
Resistant Cell Line ◽  
Resistant Variant ◽  
Normal Tissues ◽  
Immunoblotting Assay ◽  
Human Solid Tumors

A membrane purification procedure and an immunoblotting assay have been designed to allow screening of human solid tumors for overexpression of the GP170 glycoprotein without employing a disaggregation method to obtain cell suspensions. The electrophoresed membrane proteins were probed, after Western Blotting, with the C219 monoclonal antibody and iodinated Protein A. The labeling intensity of the bands on the autoradioimmunoblots were quantified by densitometry. To test for the presence of GP170, we used membranes from the UV 2237 fibrosarcoma line and its adriamycin-resistant variant ADMR, grown in vitro or as solid tumor in mice. Membranes of human normal and tumor tissues obtained from previously untreated patients were also tested. An immunoreaction was observed in the adriamycin-resistant UV 2237 lines grown in vitro or in vivo. Quantitatively, the binding of the resistant cell line grown in vitro was higher than that observed in cells grown in mice. Bands in the GP 170 region were observed in 4/7 normal and in 7/7 tumor colon tissues and in the normal medulla from 2 patients with cancer of the renal cortex. No reaction could be found in samples from normal tissue, primary tumor or nodal metastasis from 7 patients with breast cancer.

Epigenetic approaches to cancer therapy

2004 ◽  
Vol 32 (6) ◽  
pp. 1095-1097 ◽  
Author(s):  
J.A. Plumb ◽  
N. Steele ◽  
P.W. Finn ◽  
R. Brown
Keyword(s):  
Dna Methylation ◽  
Cell Line ◽  
Gene Promoter ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Tumour Suppressor Genes ◽  
Control Of Gene Expression ◽  
Hmlh1 Gene

Histone deacetylation and DNA methylation have a central role in the control of gene expression, including transcriptional repression of tumour suppressor genes. Loss of DNA mismatch repair due to methylation of the hMLH1 gene promoter results in resistance to cisplatin in vitro and in vivo. The cisplatin-resistant cell line A2780/cp70 is 8-fold more resistant to cisplatin than the non-resistant cell line, and has the hMLH1 gene methylated. Treatment with an inhibitor of DNA methyltransferase, DAC (2-deoxy-5′-azacytidine), results in a partial reversal of DNA methylation, re-expression of MLH1 (mutL homologue 1) and sensitization to cisplatin both in vitro and in vivo. PXD101 is a novel hydroxamate type histone deacetylase inhibitor that shows antitumour activity in vivo and is currently in phase I clinical evaluation. Treatment of A2780/cp70 tumour-bearing mice with DAC followed by PXD101 results in a marked increase in the number of cells that re-express MLH1. Since the clinical use of DAC may be limited by toxicity and eventual re-methylation of genes, we suggest that the combination of DAC and PXD101 could have a role in increasing the efficacy of chemotherapy in patients with tumours that lack MLH1 expression due to hMLH1 gene promoter methylation.

scholarly journals Non-canonical AR activity facilitates endocrine resistance in breast cancer

2019 ◽  
Vol 26 (2) ◽  
pp. 251-264 ◽  
Author(s):  
KeeMing Chia ◽  
Heloisa Milioli ◽  
Neil Portman ◽  
Geraldine Laven-Law ◽  
Rhiannon Coulson ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Clinical Trials ◽  
Endocrine Resistance ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Breast Cancer Cell Lines ◽  
Microarray Gene Expression ◽  
Pdx Model

The role of androgen receptor (AR) in endocrine-resistant breast cancer is controversial and clinical trials targeting AR with an AR antagonist (e.g., enzalutamide) have been initiated. Here, we investigated the consequence of AR antagonism using in vitro and in vivo models of endocrine resistance. AR antagonism in MCF7-derived tamoxifen-resistant (TamR) and long-term estrogen-deprived breast cancer cell lines were achieved using siRNA-mediated knockdown or pharmacological inhibition with enzalutamide. The efficacy of enzalutamide was further assessed in vivo in an estrogen-independent endocrine-resistant patient-derived xenograft (PDX) model. Knockdown of AR inhibited the growth of the endocrine-resistant cell line models. Microarray gene expression profiling of the TamR cells following AR knockdown revealed perturbations in proliferative signaling pathways upregulated in endocrine resistance. AR loss also increased some canonical ER signaling events and restored sensitivity of TamR cells to tamoxifen. In contrast, enzalutamide did not recapitulate the effect of AR knockdown in vitro, even though it inhibited canonical AR signaling, which suggests that it is the non-canonical AR activity that facilitated endocrine resistance. Enzalutamide had demonstrable efficacy in inhibiting AR activity in vivo but did not affect the growth of the endocrine-resistant PDX model. Our findings implicate non-canonical AR activity in facilitating an endocrine-resistant phenotype in breast cancer. Unlike canonical AR signaling which is inhibited by enzalutamide, non-canonical AR activity is not effectively antagonized by enzalutamide, and this has important implications in the design of future AR-targeted clinical trials in endocrine-resistant breast cancer.

scholarly journals GSK1838705a, an IGF-1R/ALK Inhibitor, Overcomes Resistance to Crizotinib in ALK-Positive ALCL

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4069-4069
Author(s):  
Wenyu Shi ◽  
Jian-Yong Li
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Large Cell ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Expression Level ◽  
Downstream Signaling ◽  
Single Drug

Anaplastic large cell lymphoma (ALCL) is a type of CD30-expressing non-Hodgkin's lymphoma (NHL), which accounts for 2% to 3% of adult non-Hodgkin's lymphoma,accounting for 15% to 30% of children with large cell lymphoma. Anaplastic lymphoma kinase (ALK) positive ALCL is highly invasive, and currently it is generally based on CHOP combined with chemotherapy. The proportion of patients with complete relief of symptoms is as high as 90%, but the proportion of recurrence is also as high as 40%. Crizotinib is the first generation of ALK inhibitors that have been approved for the treatment of ALK+ ALCL. Unfortunately, most patients treated with crizotinib relapse after a significant initial response. The median progression-free survival of clinical trials was 10.5 months. Various mutations in the ALK kinase domain and amplification of the ALK gene copy number, activation of the alternative pathway, and tumor heterogeneity are major causes of crizotinib resistance. Studies have shown that IGF-1R interacts with NPM-ALK to promote ALK+ALCL transformation, proliferation and migration. GSK is a small molecule kinase inhibitor that inhibits both IGF-IR and ALK. Therefore, GSK with simultaneous inhibition of the bidirectional potential of IGF-IR and ALK has a promising prospect in the targeted therapy of NPM-ALK+ALCL. This study explored the inhibitory effects of GSK on NPM-ALK+ALCL and crizotinib-resistant NPM-ALK+ALCL by in vivo and in vitro experiments. In vitro experiments: The sensitivity of ALCL cell line to GSK1838705a was detected by CCK8 and flow cytometry. The expression of phosphorylation of IGF-1R and NPM-ALK signaling pathway in Karpas299 and SR786 cell lines stimulated by GSK was detected by WB method. In order to study the crizotinib resistance mutation, we established ALK+ALCL crizotinib-resistant cell lines Karpas299-R and SR786-R, and identified the resistance of Karpas299-R and SR786-R cell lines by CCK8 and flow cytometry. The drug-resistant and non-resistant strains were stimulated with gradient concentrations of crizotinib and gradient GSK, and the IC50 of the two were compared by CCK8. The WB method was used to compare the phosphorylation levels of downstream signaling pathways in drug-resistant and non-resistant strains. In vivo experiment: The ALK+ALCL and resistant-ALK+ALCL mouse model was established, and three groups of mice treated with control, GSK single drug 30 mg/kg, GSK single drug 60 mg/kg, were established. The tumor volume and body weight of the four groups were compared. Immunohistochemistry was used to compare the expression levels of key signaling molecules and apoptotic proteins in each group. SPSS statistical software draws survival curves. As the concentration of GSK gradually increases, the survival rate of ALCL cells gradually decreases. The expression of pIGF-1R, pNPM-ALK, pSTAT3, pAKT, casepase3 and other molecules decreased in the downstream signaling pathway, and the expression level of cleaved-casepase3 increased.In the crizotinib-resistant cell line, with the increase of the concentration of GSK, the apoptosis rate of the cells increased and the phosphorylation level of the downstream molecules gradually decreased. Tumor volume of three groups of mouse models: control>GSK single drug 30 mg/kg>GSK single drug 60 mg/kg. Immunohistochemistry results showed that the expression level of key signaling molecules in GSK-treated CHOP-treated mice decreased, and the expression level of apoptotic proteins increased. In this research, we explored the effects of GSK1838705A on proliferation, apoptosis, and clonogenesis of ALCL cell lines. Subsequently, we established a crizotinib-resistant cell line and noticed that GSK1838705A can effectively reduce the viability of resistant ALCL cells and significantly restrain the transmission of downstream survival signaling pathways induced by IGF1R/IR phosphorylation. Besides, we discovered that GSK1838705A inhibited the development of both crizotinib-sensitive and crizotinib-resistant ALCL tumors in the ALCL mouse model established by subcutaneous tumorigenesis. Based on the results of previous clinical trials, we put forward to use GSK1838705A as an alternative treatment strategy to overcome crizotinib-resistant ALCL. Disclosures No relevant conflicts of interest to declare.

Mitotracker Green Is a P-Glycoprotein Substrate

2003 ◽  
Vol 23 (4) ◽  
pp. 199-212 ◽  
Author(s):  
Luis F. Marques-Santos ◽  
José G. P. Oliveira ◽  
Raquel C. Maia ◽  
Vivian M. Rumjanek
Keyword(s):  
Cell Line ◽  
Fluorescent Dyes ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Normal Tissues ◽  
P Glycoprotein ◽  
Erythroleukemic Cell ◽  
Erythroleukemic Cell Line ◽  
Mitotracker Green

P-glycoprotein has a widespread expression on normal tissues. The protein has also been strongly associated with the multidrug resistance phenotype (MDR) on tumor cells. The employment of flow cytometry and confocal microscopy has contributed to the discovery and application of new particular fluorescent dyes. Nevertheless, several studies are being performed in different cellular types neglecting the expression activity of MDR proteins. Because many fluorochromes have been reported as P-glycoprotein substrates, an especial attention must be given to the properties of new dyes in the presence of MDR proteins. Flow cytometric analyzes of Mitotracker Green (MTG) fluorescence profile were performed in a human erythroleukemic cell line and its resistant counterpart. In this report we demonstrated that MTG, a probe used to evaluate the mitochondrial mass, is a P-glycoprotein substrate and its staining profile is dependent on the activity of this protein. In vitro studies on a human erythroleukemic cell line and its resistant counterpart revealed that MDR modulators (Cyclosporin A, Verapamil, and Trifluoperazine) alter the MTG fluorescence pattern on a resistant cell line. The findings suggest that attention should be given to the expression of P-glycoprotein when performing an evaluation of mitochondria properties with MTG.

scholarly journals BRAFV600 inhibition alters the microRNA cargo in the vesicular secretome of malignant melanoma cells

2017 ◽  
Vol 114 (29) ◽  
pp. E5930-E5939 ◽  
Author(s):  
Taral R. Lunavat ◽  
Lesley Cheng ◽  
Berglind O. Einarsdottir ◽  
Roger Olofsson Bagge ◽  
Somsundar Veppil Muralidharan ◽  
...  
Keyword(s):  
Malignant Melanoma ◽  
Melanoma Cells ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Braf Inhibitors ◽  
Braf Inhibition ◽  
Survival Pathway ◽  
Tumor Tissues

The BRAF inhibitors vemurafenib and dabrafenib can be used to treat patients with metastatic melanomas harboring BRAFV600 mutations. Initial antitumoral responses are often seen, but drug-resistant clones with reactivation of the MEK–ERK pathway soon appear. Recently, the secretome of tumor-derived extracellular vesicles (EVs) has been ascribed important functions in cancers. To elucidate the possible functions of EVs in BRAF-mutant melanoma, we determined the RNA content of the EVs, including apoptotic bodies, microvesicles, and exosomes, released from such cancer cells after vemurafenib treatment. We found that vemurafenib significantly increased the total RNA and protein content of the released EVs and caused significant changes in the RNA profiles. RNA sequencing and quantitative PCR show that cells and EVs from vemurafenib-treated cell cultures and tumor tissues harvested from cell-derived and patient-derived xenografts harbor unique miRNAs, especially increased expression of miR-211–5p. Mechanistically, the expression of miR-211–5p as a result of BRAF inhibition was induced by increased expression of MITF that regulates the TRPM1 gene resulting in activation of the survival pathway. In addition, transfection of miR-211 in melanoma cells reduced the sensitivity to vemurafenib treatment, whereas miR-211–5p inhibition in a vemurafenib resistant cell line affected the proliferation negatively. Taken together, our results show that vemurafenib treatment induces miR-211–5p up-regulation in melanoma cells both in vitro and in vivo, as well as in subsets of EVs, suggesting that EVs may provide a tool to understand malignant melanoma progression.

scholarly journals Activation of MAT2A-RIP1 signaling axis reprograms monocytes in gastric cancer

2021 ◽  
Vol 9 (2) ◽  
pp. e001364
Author(s):  
Yan Zhang ◽  
Hui Yang ◽  
Jun Zhao ◽  
Ping Wan ◽  
Ye Hu ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Metabolism ◽  
Vital Role ◽  
Methionine Metabolism ◽  
Promoter Regions ◽  
Normal Tissues ◽  
Methionine Cycle

BackgroundThe activation of tumor-associated macrophages (TAMs) facilitates the progression of gastric cancer (GC). Cell metabolism reprogramming has been shown to play a vital role in the polarization of TAMs. However, the role of methionine metabolism in function of TAMs remains to be explored.MethodsMonocytes/macrophages were isolated from peripheral blood, tumor tissues or normal tissues from healthy donors or patients with GC. The role of methionine metabolism in the activation of TAMs was evaluated with both in vivo analyses and in vitro experiments. Pharmacological inhibition of the methionine cycle and modulation of key metabolic genes was employed, where molecular and biological analyses were performed.ResultsTAMs have increased methionine cycle activity that are mainly attributed to elevated methionine adenosyltransferase II alpha (MAT2A) levels. MAT2A modulates the activation and maintenance of the phenotype of TAMs and mediates the upregulation of RIP1 by increasing the histone H3K4 methylation (H3K4me3) at its promoter regions.ConclusionsOur data cast light on a novel mechanism by which methionine metabolism regulates the anti-inflammatory functions of monocytes in GC. MAT2A might be a potential therapeutic target for cancer cells as well as TAMs in GC.

scholarly journals LINC00958 promotes the proliferation of TSCC via miR-211-5p/CENPK axis and activating the JAK/STAT3 signaling pathway

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Bo Jia ◽  
Junfeng Dao ◽  
Jiusong Han ◽  
Zhijie Huang ◽  
Xiang Sun ◽  
...  
Keyword(s):  
Noncoding Rna ◽  
Xenograft Model ◽  
Tumor Xenograft ◽  
Luciferase Reporter ◽  
Cell Cycle Regulators ◽  
Normal Tissues ◽  
Stat3 Signaling ◽  
Long Intergenic Noncoding Rna

Abstract Background Tongue squamous cell carcinoma (TSCC) is one of the most common oral tumors. Recently, long intergenic noncoding RNA 00958 (LINC00958) has been identified as an oncogene in human cancers. Nevertheless, the role of LINC00958 and its downstream mechanisms in TSCC is still unknown. Methods The effect of LINC00958 on TSCC cells proliferation and growth were assessed by CCK-8, colony formation, 5-Ethynyl-2′-deoxyuridline (EdU) assay and flow cytometry assays in vitro and tumor xenograft model in vivo. Bioinformatics analysis was used to predict the target of LINC00958 in TSCC, which was verified by RNA immunoprecipitation and luciferase reporter assays. Results LINC00958 was increased in TSCC tissues, and patients with high LINC00958 expression had a shorter overall survival. LINC00958 knockdown significantly decreased the growth rate of TSCC cells both in vitro and in vivo. In mechanism, LINC00958 acted as a ceRNA by competitively sponging miR-211-5p. In addition, we identified CENPK as a direct target gene of miR-211-5p, which was higher in TSCC tissues than that in adjacent normal tissues. Up-regulated miR-211-5p or down-regulated CENPK could abolish LINC00958-induced proliferation promotion in TSCC cells. Furthermore, The overexpression of CENPK promoted the expression of oncogenic cell cycle regulators and activated the JAK/STAT3 signaling. Conclusions Our findings suggested that LINC00958 is a potential prognostic biomarker in TSCC.

scholarly journals Characterization of the SARS-CoV-2 coronavirus X4-like accessory protein

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Olanrewaju Ayodeji Durojaye ◽  
Nkwachukwu Oziamara Okoro ◽  
Arome Solomon Odiba
Keyword(s):  
Rapid Development ◽  
Protein A ◽  
The Novel ◽  
Quality Model ◽  
A Value ◽  
Model Protein ◽  
Novel Coronavirus ◽  
Global Threat

Abstract Background The novel coronavirus SARS-CoV-2 is currently a global threat to health and economies. Therapeutics and vaccines are in rapid development; however, none of these therapeutics are considered as absolute cure, and the potential to mutate makes it necessary to find therapeutics that target a highly conserved regions of the viral structure. Results In this study, we characterized an essential but poorly understood coronavirus accessory X4 protein, a core and stable component of the SARS-CoV family. Sequence analysis shows a conserved ~ 90% identity between the SARS-CoV-2 and previously characterized X4 protein in the database. QMEAN Z score of the model protein shows a value of around 0.5, within the acceptable range 0–1. A MolProbity score of 2.96 was obtained for the model protein and indicates a good quality model. The model has Ramachandran values of φ = − 57o and ψ = − 47o for α-helices and values of φ = − 130o and ψ = + 140o for twisted sheets. Conclusions The protein data obtained from this study provides robust information for further in vitro and in vivo experiment, targeted at devising therapeutics against the virus. Phylogenetic analysis further supports previous evidence that the SARS-CoV-2 is positioned with the SL-CoVZC45, BtRs-BetaCoV/YN2018B and the RS4231 Bat SARS-like corona viruses.

scholarly journals The Yeast Recombinational Repair Protein Rad59 Interacts With Rad52 and Stimulates Single-Strand Annealing

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 515-525 ◽  
Author(s):  
Allison P Davis ◽  
Lorraine S Symington
Keyword(s):  
Protein A ◽  
Single Strand ◽  
Physical Interaction ◽  
Dna Double Strand Breaks ◽  
Single Stranded Dna ◽  
Single Strand Annealing ◽  
Strand Annealing ◽  
Recombination Pathway

Abstract The yeast RAD52 gene is essential for homology-dependent repair of DNA double-strand breaks. In vitro, Rad52 binds to single- and double-stranded DNA and promotes annealing of complementary single-stranded DNA. Genetic studies indicate that the Rad52 and Rad59 proteins act in the same recombination pathway either as a complex or through overlapping functions. Here we demonstrate physical interaction between Rad52 and Rad59 using the yeast two-hybrid system and co-immunoprecipitation from yeast extracts. Purified Rad59 efficiently anneals complementary oligonucleotides and is able to overcome the inhibition to annealing imposed by replication protein A (RPA). Although Rad59 has strand-annealing activity by itself in vitro, this activity is insufficient to promote strand annealing in vivo in the absence of Rad52. The rfa1-D288Y allele partially suppresses the in vivo strand-annealing defect of rad52 mutants, but this is independent of RAD59. These results suggest that in vivo Rad59 is unable to compete with RPA for single-stranded DNA and therefore is unable to promote single-strand annealing. Instead, Rad59 appears to augment the activity of Rad52 in strand annealing.

scholarly journals DPP3/CDK1 contributes to the progression of colorectal cancer through regulating cell proliferation, cell apoptosis, and cell migration

2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Yixin Tong ◽  
Yuan Huang ◽  
Yuchao Zhang ◽  
Xiangtai Zeng ◽  
Mei Yan ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Cell Migration ◽  
Cell Apoptosis ◽  
Downstream Target ◽  
Normal Tissues ◽  
Physiological Processes ◽  
Mutual Regulation

AbstractAt present, colorectal cancer (CRC) has become a serious threat to human health in the world. Dipeptidyl peptidase 3 (DPP3) is a zinc-dependent hydrolase that may be involved in several physiological processes. However, whether DPP3 affects the development and progression of CRC remains a mystery. This study is the first to demonstrate the role of DPP3 in CRC. Firstly, the results of immunohistochemistry analysis showed the upregulation of DPP3 in CRC tissues compared with normal tissues, which is statistically analyzed to be positively correlated with lymphatic metastasis, pathological stage, positive number of lymph nodes. Moreover, the high expression of DPP3 predicts poor prognosis in CRC patients. In addition, the results of cell dysfunction experiments clarified that the downregulation of DPP3 significantly inhibited cell proliferation, colony formation, cell migration, and promoted apoptosis in vitro. DPP3 depletion could induce cell apoptosis by upregulating the expression of BID, BIM, Caspase3, Caspase8, HSP60, p21, p27, p53, and SMAC. In addition, downregulation of DPP3 can reduce tumorigenicity of CRC cells in vivo. Furthermore, CDK1 is determined to be a downstream target of DPP3-mediated regulation of CRC by RNA-seq, qPCR, and WB. The interaction between DPP3 and CDK1 shows mutual regulation. Specifically, downregulation of DPP3 can accentuate the effects of CDK1 knockdown on the function of CRC cells. Overexpression of CDK1 alleviates the inhibitory effects of DPP3 knockdown in CRC cells. In summary, DPP3 has oncogene-like functions in the development and progression of CRC by targeting CDK1, which may be an effective molecular target for the prognosis and treatment of CRC.

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