Search results for "Viability"
showing 10 items of 402 documents
The potential of acetaminophen as a prodrug in gene-directed enzyme prodrug therapy.
2000
Acetaminophen is oxidized by human CYP1A2 to the cytotoxic metabolite N-acetylbenzoquinoneimine (NABQI). Incubation of cells transfected with human CYP1A2 (H1A2 MZ cells) with 4-20 mM acetaminophen for 6 hours at 37 degrees C caused extensive cytotoxicity (cell viability10%). In contrast, nontransfected V79 MZ cells were unaffected (viability95%). By mixing H1A2 MZ cells with V79 MZ cells in various proportions and incubating with 4 mM acetaminophen, it was shown that the NABQI released from H1A2 MZ cells also caused cytotoxicity of bystander cells. Thus, in a mixture containing 5% H1A2 MZ cells, exposure to 4 mM acetaminophen for 6 hours resulted in complete cell killing by 24 hours. A sim…
The Impact of Insulin on Low-dose Metronomic Vinorelbine and Mafosfamide in Breast Cancer Cells
2021
Background/aim Breast cancer (BC) may be affected by diabetes and anti-diabetic medication, as well as its therapeutic agents. Low-dose metronomic chemotherapy (LDMC) is an available treatment option in BC. We investigated the impact of insulin on low-dose metronomic vinorelbine and mafosfamide in BC cell lines. Materials and methods Human BC cell lines T-47D, MCF-7, MDA-MB-231, BT-549 and non-tumorigenic breast cell line MCF-10A were exposed to 0.01 μg/ml and 10 μg/ml insulin in combination with low-dose metronomic vinorelbine or mafosfamide. The cell viability was determined after 24-72 hours using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Results Insulin, especi…
Abstract 1138: The protein disulfide isomerase inhibitor XCE853 inhibits in vitro, ex-vivo and in vivo growth of human tumors
2017
Abstract Protein disulfide isomerase (PDI) is a chaperone protein that regulates oxidative protein folding as well as cell viability. Increased PDI levels have been documented in a variety of human cancers associated with a poor overall survival, including ovarian, prostate, brain and lung cancers. Inhibition of PDI activity leads to apoptosis in cancer, suggesting that PDI is a promising druggable target. XCE853 is a synthetic small molecule displaying an excellent docking with the catalytic domain of the human PDI. XCE853 inhibits in vitro recombinant PDI enzymatic activity. In addition, the proliferation of a large panel of human tumor cells is blocked by XCE853 with IC50s in the nanomol…
Selectivity analysis of protein kinase CK2 inhibitors DMAT, TBB and resorufin in cisplatin-induced stress responses.
2009
Udgivelsesdato: 2009-Nov Targeting protein kinases as a therapeutic approach to treat various diseases, especially cancer is currently a fast growing business. Although many inhibitors are available, exhibiting remarkable potency, the major challenge is their selectivity. Here we show that the protein kinase CK2 inhibitors DMAT, TBB and resorufin differ in their selectivity against PI3K family members, since PI3K and DNA-PK are subject to inhibition by DMAT and TBB, however, not by resorufin. TBB and DMAT treatment together with cisplatin lead to an inhibition of cisplatin-induced stress signaling (as detected by phosphorylation of JNK and H2AX). In the case of resorufin no interference wit…
WIN induces apoptotic cell death in human colon cancer cells through a block of autophagic flux dependent on PPARγ down-regulation.
2014
Cannabinoids have been reported to possess anti-tumorigenic activity in cancer models although their mechanism of action is not well understood. Here, we show that the synthetic cannabinoid WIN55,212-2 (WIN)-induced apoptosis in colon cancer cell lines is accompanied by endoplasmic reticulum stress induction. The formation of acidic vacuoles and the increase in LC3-II protein indicated the involvement of autophagic process which seemed to play a pro-survival role against the cytotoxic effects of the drug. However, the enhanced lysosomal membrane permeabilization (LMP) blocked the autophagic flux after the formation of autophagosomes as demonstrated by the accumulation of p62 and LC3, two ma…
Relation of early Photofrin uptake to photodynamically induced phototoxicity and changes of cell volume in different cell lines.
1994
For efficacy of photodynamic therapy, selective uptake and retention of photoactive substances has been postulated. Therefore, measurements were performed to find out whether the photosensitiser Photofrin® is taken up differently in malignant and non-malignant cells in vitro . In addition, the sensitivity of malignant cells and nonmalignant cells to photodynamic exposure was investigated, by quantifying viability and volume alterations of the cells. Bovine aortic endothelial cells, mouse fibroblasts and amelanotic hamster melanoma cells were suspended in a specially designed incubation chamber under controlled conditions (e.g. pH, p O 2 , p CO 2 and temperature). After establishing constant…
Sodium phenylbutyrate induces apoptosis in human retinoblastoma Y79 cells: The effect of combined treatment with the topoisomerase I-inhibitor topote…
2001
Our results demonstrate that sodium phenylbutyrate, a compound with a low degree of toxicity, exerted a cytotoxic effect on human retinoblastoma Y79 cells in a time- and dose-dependent manner. Treatment of Y79 cells for 72 h with phenylbutyrate reduced cell viability by 63% at 2 mM and 90% at 4 mM. Cell death caused by phenylbutyrate exhibited the typical features of apoptosis, as shown by light and fluorescent microscopy. Western blot analysis demonstrated that exposure of Y79 cells to phenylbutyrate decreased the level of the antiapoptotic factor Bcl-2 and induced the activation of caspase-3, a key enzyme in the execution phase of apoptosis. Moreover, treatment with phenylbutyrate markedl…
Three-dimensional cell culture induces novel proliferative and metabolic alterations associated with oncogenic transformation
1996
To date, cell biological characteristics of oncogene-transfected cells have been investigated either in relatively homogeneous monolayer cultures or in heterogeneous tumors in vivo. To evaluate the emergence of cellular heterogeneity during tumor formation, we have established a multicellular spheroid system from an oncogene-dependent, genetically determined 2-stage carcinogenesis model for 3-dimensional growth under well-defined conditions. The effect of T24Ha-ras transfection on cellular growth, proliferation, cell viability and oxygenation was investigated using spontaneously immortalized (Rat1) and c-myc-transfected (M1) Fisher 344 rat embryo fibroblasts and a tumorigenic T24Ha-ras-tran…
Abstract 1778: Preclinical characterization of the safety and antitumor activity of IMAB027-vcMMAE, an anticlaudin 6 antibody-drug conjugate
2018
Abstract Background Claudin 6 (CLDN6) is a tight junction membrane protein whose expression in normal tissue is confined to embryonic cells, but is aberrantly expressed in various human cancers. The anti-CLDN6 monoclonal antibody (mAb), IMAB027, has shown promising antitumor activity in preclinical human CLDN6-positive (CLDN6+) cancer models. Conjugation of IMAB027 with monomethyl auristatin E (MMAE) may utilize the precision tumor-targeting of the mAb to deliver a highly effective cytotoxic drug to the tumor. In this report we present the preclinical characterization of this antibody–drug conjugate, IMAB027–vcMMAE. Methods Internalization of IMAB027 in various CLDN6+ human ovarian (OC) and…
Abstract 1855: Role of mTOR inhibition in triple-negative breast cancer
2016
Abstract BACKGROUND: Triple-negative breast cancers (TNBC) represent the 10-17% of all diagnosed breast cancers (BC) and are characterized by the absence of ER/PgR expression, HER2 amplification and often show a basal-like phenotype. TNBC are often diagnosed in patients with BRCA1 germline mutation and unfortunately treatment options are still limited. The mTOR (Mammalian Target Of Rapamycin) pathway seems to play an important role in BC pathogenesis and it is possible to target this pathway by inhibitors such as rapamycin. In human BC cross talk between ER/PgR receptors signaling and the mTOR pathway is believed to be responsible for resistance to hormone therapy probably due to a down reg…