Highly efficient radiosensitization of human glioblastoma and lung cancer cells by a G-quadruplex DNA binding compound.

Telomeres are nucleoprotein structures at the end of chromosomes which stabilize and protect them from nucleotidic degradation and end-to-end fusions. The G-rich telomeric single-stranded DNA overhang can adopt a four-stranded G-quadruplex DNA structure (G4). Stabilization of the G4 structure by binding of small molecule ligands enhances radiosensitivity of tumor cells, and this combined treatment represents a novel anticancer approach.

In vivo efficacy of melanoma internal radionuclide therapy with a 131I-labelled melanin-targeting heteroarylcarboxamide molecule.

The development of alternative therapies for melanoma treatment is of great interest as long-term tumour regression is not achieved with new targeted chemotherapies on selected patients. We previously demonstrated that radioiodinated heteroarylcarboxamide ([131I]ICF01012) induced a strong anti-tumoural effect by inhibiting both primary tumour growth and dissemination process in a B16BL6 melanoma model. In our study, we show that a single injection of [131I]ICF01012 (ranging from 14.

Quaternary ammonium-melphalan conjugate for anticancer therapy of chondrosarcoma: in vitro and in vivo preclinical studies.

Cartilage tumours present ongoing therapeutic challenges due to their chondrogenic extracellular matrix that potentially hampers drug delivery, their low percentage of dividing cells, and their poor vascularity. In this context, and based on the affinity of the quaternary ammonium moiety for proteoglycans (PG), we developed a strategy that uses the quaternary ammonium function to selectively deliver DNA alkylating agents to the cartilage tumour tissue. We engineered the quaternary ammonium derivative of melphalan (Mel-AQ) and assessed its antitumoural activity in vitro and in vivo.

Intramolecular cyclization of N-phenyl N'(2-chloroethyl)ureas leads to active N-phenyl-4,5-dihydrooxazol-2-amines alkylating β-tubulin Glu198 and prohibitin Asp40.

The cyclization of anticancer drugs into active intermediates has been reported mainly for DNA alkylating molecules including nitrosoureas. We previously defined the original cytotoxic mechanism of anticancerous N-phenyl-N'-(2-chloroethyl)ureas (CEUs) that involves their reactivity towards cellular proteins and not against DNA; two CEU subsets have been shown to alkylate β-tubulin and prohibitin leading to inhibition of cell proliferation by G₂/M or G₁/S cell cycle arrest. In this study, we demonstrated that cyclic derivatives of CEUs, N-phenyl-4,5-dihydrooxazol-2-amines (Oxas) are two- to threefold more active than CEUs and share the same cytotoxic properties in B16F0 melanoma cells.

AKT and p21 WAF1/CIP1 as potential genistein targets in BRCA1-mutant human breast cancer cell lines.

BRCA1 acts as a tumour suppressor and germ-line mutations within this gene are found in a large proportion of families with breast cancer. The aim of our study was to unravel the mechanism of action of genistein, the major soy phytoestrogen, in BRCA1-mutant human breast cancer cell lines. Four breast cancer cell lines were studied for their response to genistein, three of them harbouring different mutations within the BRCA1 gene (HCC1937, SUM149 and SUM1315 cells) and the MDA-MB-231 cell line, which expresses a functional BRCA1 protein.

Apoptosis and meiotic segregation in ejaculated sperm from Robertsonian translocation carrier patients.

Background: To better understand the infertility of patients with Robertsonian translocation, the biochemical and ultrastructural apoptotic characteristics of apoptosis in the sperm of patients and fertile donors were studied.

Methods: Ejaculated sperm samples of seven Robertsonian translocation carriers and seven fertile donors were analyzed after cryopreservation. The proportion of both viable and dead spermatozoa expressing activated caspases was detected by flow cytometry through the use of different specific carboxyfluorescein-labeled caspase inhibitors.

Liver X Receptor activation downregulates AKT survival signaling in lipid rafts and induces apoptosis of prostate cancer cells.

Cholesterol is a structural component of lipid rafts within the plasma membrane. These domains, used as platforms for various signaling molecules, regulate cellular processes including cell survival. Cholesterol contents are tightly correlated with the structure and function of lipid rafts.

Breast cancer cell response to genistein is conditioned by BRCA1 mutations.

Soy phytoestrogens, among which genistein, seem to protect from breast cancer development. In order to study the role of the breast tumour suppressor BRCA1 in response to genistein, we used a new breast cancer cell model: the SUM1315MO2 cell line carrying the 185delAG BRCA1 mutation, which we stably transfected with a plasmid encoding wild-type BRCA1. We showed that growth of BRCA1 mutant cells was strongly inhibited by genistein whereas it only had a weak effect in cells expressing wild-type BRCA1 protein.

Fluorescence microscopy and flow cytometry in measuring activated caspases in human spermatozoa.

Staining of spermatozoa with the fluorescein-Val-Ala-Asp-fluoromethylketone has already been performed on ejaculated sperm samples, using fluorescence microscopy (FM) or flow cytometry (FCM) in order to score activated caspases. This assay may help in assessing apoptosis and its role in male fertility. The present study compares the above two techniques in order to adopt the most accurate method for detection in human frozen-thawed testicular, epididymal and ejaculated spermatozoa.

Alkylation of prohibitin by cyclohexylphenyl-chloroethyl urea on an aspartyl residue is associated with cell cycle G(1) arrest in B16 cells.

Background And Purpose: Phenyl-chloroethyl ureas (CEUs) are a class of anticancer drugs that mainly react with proteins. Two molecules of this family, cyclohexylphenyl-chloroethyl urea (CCEU) and iodophenyl-chloroethyl urea (ICEU) induced G(1)/S and G(2)/M cell cycle blocks, respectively. We hypothesised that these observations were linked to a differential protein alkylation pattern.

Crosstalk between androgen receptor and epidermal growth factor receptor-signalling pathways: a molecular switch for epithelial cell differentiation.

In the male, androgens promote growth and differentiation of sex reproductive organs through ligand activation of the androgen receptor (AR). Here, we show that androgens are not major actors of the cell cycle arrest associated with the differentiation process, and that the epidermal growth factor (EGF)-mediated signalling interferes with AR activities to regulate androgen response when epithelial cells are differentiated. Higher AR expression and enhanced androgen responsiveness correlate with reduction of phosphorylated ERK1/2 over differentiation.

N-(4-iodophenyl)-N'-(2-chloroethyl)urea as a microtubule disrupter: in vitro and in vivo profiling of antitumoral activity on CT-26 murine colon carcinoma cell line cultured and grafted to mice.

The antitumoral profile of the microtubule disrupter N-(4-iodophenyl)-N'-(2-chloroethyl)urea (ICEU) was characterised in vitro and in vivo using the CT-26 colon carcinoma cell line, on the basis of the drug uptake by the cells, the modifications of cell cycle, and beta-tubulin and lipid membrane profiles. N-(4-iodophenyl)-N'-(2-chloroethyl)urea exhibited a rapid and dose-dependent uptake by CT-26 cells suggesting its passive diffusion through the membranes. Intraperitoneally injected ICEU biodistributed into the grafted CT-26 tumour, resulting thus in a significant tumour growth inhibition (TGI).

In addition to membrane injury, an affinity for melanin might be involved in the high sensitivity of human melanoma cells to hederacolchiside A1.

We previously reported that hederacolchiside A1 (Hcol A1), a new oleanene saponin isolated from Hedera colchica Koch (Araliaceae) exhibits a preferential cytotoxicity on a pigmented melanoma cell line. The present study confirms the high susceptibility of melanoma cell lines to this drug and shows concentrations producing a 50% decrease in cell content (IC50 values) inversely proportional to the melanin content of each cell line. At cytotoxic concentrations, Hcol A1 induces membrane-damaging effects within 6 h, cytoplasmic vacuolization within 24 h, and non-apoptotic cell death within 48 h.

Androgen receptor mediates non-genomic activation of phosphatidylinositol 3-OH kinase in androgen-sensitive epithelial cells.

Androgens are known to modulate many cellular processes such as cell growth and survival by binding to the androgen receptor (AR) and activating the transcription of target genes. Recent data suggested that AR can also mediate non-transcriptional actions outside the nucleus in addition to its ligand-inducible transcription factor function. Here, we describe a transcription-independent activation of the phosphatidylinositol 3-OH kinase (PI3-K) signaling pathway by androgens.

Resveratrol increases BRCA1 and BRCA2 mRNA expression in breast tumour cell lines.

The phytochemical resveratrol, found in grapes, berries and peanuts, has been found to possess cancer chemopreventive effects by inhibiting diverse cellular events associated with tumour initiation, promotion and progression. Resveratrol is also a phyto-oestrogen, binds to and activates oestrogen receptors that regulate the transcription of oestrogen-responsive target genes such as the breast cancer susceptibility genes BRCA1 and BRCA2. We investigated the effects of resveratrol on BRCA1 and BRCA2 expression in human breast cancer cell lines (MCF7, HBL 100 and MDA-MB 231) using quantitative real-time RT-PCR, and by perfusion chromatography of the proteins.

Expression of BRCA1 and BRCA2 in different tumor cell lines with various growth status.

Background: BRCA1 and BRCA2 are breast cancer susceptibility genes. Recent studies suggest that BRCA1 interacts with a great variety of proteins, including BRCA2, cell-cycle regulators, transcriptional activators and repressors. We investigated the expression of both BRCA1 and BRCA2 during the progression of the cell cycle of human tumor cell lines from different origins (MCF7, MDA-MB231, PA1 and CCL221) in two growth status (60% and 100% of confluency).

Hematological recovery and peripheral blood progenitor cell mobilization after induction chemotherapy and GM-CSF plus G-CSF in breast cancer.

In order to determine the effect of GM-CSF plus G-CSF in combination in breast cancer patients receiving an effective induction regimen, we compared hematological recovery and peripheral blood progenitor cell (PBPC) mobilization according to colony-stimulating factor (CSF) support. Forty-three breast cancer patients were treated by TNCF (THP-doxorubicin, vinorelbine, cyclophosphamide, fluorouracil, D1 to D4) with CSF support: 11 patients received GM-CSF (D5 to D14); 16 patients G-CSF (D5 to D14) and 16 patients GM-CSF (D5-D14) plus G-CSF (D10-D14). Between two subsequent cycles, progenitor cells were assessed daily, from D13 to D17.

Isolation, purification and quantification of BRCA1 protein from tumour cells by affinity perfusion chromatography.

A new procedure for the isolation, purification and quantification of the product of the oncosuppressor gene brca1 in breast tissues, was carried out. It involves internal cell protein [35S]methionine labelling followed by two perfusion chromatographies. The first one is heparin affinity chromatography, to purify all of the cell DNA-binding proteins.

G2 accumulation and melanin overproduction in malignant melanocytes treated with a new nitrosourea.

Cystemustine (N'-(2-chloroethyl)-N-(2-(methylsulphonyl)ethyl)-N'-nitrosourea), a new anticancer chloroethylnitrosourea (CENU) is being tested in a phase II clinical trial of disseminated melanoma. The antitumour effect of this drug is mainly due to DNA damage in malignant melanocytes. Recently, we have shown that this damage can induce apoptosis in some melanoma cell lines.

Association of N-acetyllactosamine with tumor progression in human breast cancer: a study using a 16 kDa chick embryo lectin.

This study documents modifications in the expression and the cellular distribution of binding sites for a 16 kDa chick embryo lectin (CL16-BS) in breast cancer. This lectin binds preferentially to terminal and penultimate N-acetyllactosamine residues (Galbeta1-4GlcNAc). BS density and distribution, studied by lectin binding followed by indirect immunofluorescence, were compared in normal breast tissues and 45 invasive carcinomas (lobular and ductal).

Mobilization of peripheral blood progenitor cells after induction chemotherapy (THP-doxorubicin-vinorelbine-cyclophosphamide-fluorouracil) and granulocyte colony-stimulating factor in breast cancer.

In order to evaluate the mobilization of peripheral blood progenitor cells (PBPC) after an effective induction regimen in breast cancer, we performed a study on 15 breast cancer patients. Between January 1995 and June 1996, these patients received TNCF (THP-doxorubicin. vinorelbine, cyclophosphamide, fluorouracil for four days, every 21 days) with G-CSF support (5 microg/kg for 10 days after chemotherapy) to reduce aplasia.

rhGM-CSF vs placebo following rhGM-CSF-mobilized PBPC transplantation: a phase III double-blind randomized trial.

In this placebo-controlled randomized trial we evaluated the hematological and clinical effects of r-Hu GM-CSF after high-dose chemotherapy (HDC) followed by GM-CSF-mobilized PBPC transplantation. Fifty patients with poor prognosis malignancies were randomized in a double-blind study to receive either GM-CSF or placebo after HDC followed by PBPC rescue. For all patients, PBPCs were recruited using a combination of VP-16 (300 mg/m2 on days 1 and 2), cytoxan (3 g/m2 on days 3 and 4) and GM-CSF (5 micrograms/kg from day 5).

New method for stem cell quantification: applications to the management of peripheral blood stem cell transplantation.

A dramatic increase in peripheral blood stem cells (PBSC) is observed after high-dose chemotherapy followed by haematopoietic growth factors. The degree of mobilisation of PBSC is quantified by the level of clonogenic cells detected by CFU assays (CFU-GM or CFU-GEMM) or CD34+ cell determination. Working under the hypothesis that, in peripheral blood, mononuclear cells in DNA synthesis (MCDS) are proliferating stem cells, we decided to detect these cells by flow cytometric measurement of their DNA content.