Changes in the two-dimensional electrophoresis pattern of the Parkinson's disease related protein DJ-1 in human SH-SY5Y neuroblastoma cells after dopamine treatment.

DJ-1 is a mitochondrial protein linked to Parkinson's disease. DJ-1 has been suggested to have several possible functions, although it has been mainly associated to oxidative stress defence. Changes in the two-dimensional electrophoresis pattern have been thoroughly described as a consequence of oxidative modification of the Cys106 residue.

The IGFR1 inhibitor NVP-AEW541 disrupts a pro-survival and pro-angiogenic IGF-STAT3-HIF1 pathway in human glioblastoma cells.

Inappropriate activation of the IGF (insulin-like growth factor) system has been implicated in the growth and progression of a number of tumor types. Recent evidence indicates a possible role for the IGF system in modulating/mediating tumor cell response to hypoxia, a common occurrence in solid tumors, and particularly in malignant gliomas, causing tumor cells either to die, or to mount a pleiotropic adaptive response that is mainly orchestrated through activation of the hypoxia-inducible transcription factor HIF1. Experimental evidence suggests possible links between IGF- and HIF1-dependent signaling pathways, as well as a role for activated STAT3 in mediating their activities.

Photodynamic effects of novel 5,15-diaryl-tetrapyrrole derivatives on human colon carcinoma cells.

Preliminary in vitro cytotoxicity studies on a panel of meso diaryl-substituted tetrapyrrole derivatives newly synthesized in our laboratory have shown that these compounds are photodynamically active on the human colon carcinoma cell line HCT116. In the present study, we investigate some mechanistic aspects of the photodynamic action of the most active compounds in the series, namely the 5-phenyl-15-(3-methoxyphenyl)porphyrin (1), the 5-phenyl-15-(3-hydroxyphenyl)porphyrin (2) and the 5,15-diphenylporphyrin (3). The results of the cytotoxicity studies indicate that the novel photosensitisers (PSs) are more potent in vitro than m-THPC (Foscan), a powerful PS already approved for clinical use in photodynamic therapy (PDT).

Effect of HIF-1 modulation on the response of two- and three-dimensional cultures of human colon cancer cells to 5-fluorouracil.

Tumour hypoxia represents a major obstacle to the success of radiotherapy and chemotherapy. The discovery that the hypoxia-inducible factor 1 (HIF-1) is a master regulator of cellular response to low oxygen led to the concept that inhibiting HIF-1 activity may sensitise hypoxic cancer cells to radiation and cytotoxic drugs. In the present study we investigate the effects of HIF-1 modulation on the response of the human colon adenocarcinoma cell line HCT116 to 5-fluorouracil (5FU).

Linalool, a plant-derived monoterpene alcohol, reverses doxorubicin resistance in human breast adenocarcinoma cells.

Essential oils from various aromatic plants have been reported to exert chemopreventive and/or antitumor effects. In addition, a number of studies have shown the ability of chemopreventive phytochemicals to increase the sensitivity of cancer cells to conventional anticancer drugs. The success of chemotherapeutic agents is often hindered by the development of drug resistance, with multidrug resistant (MDR) phenotypes reported in a number of tumors, generally involving reduced intracellular drug accumulation due to increased drug efflux by membrane transporters.

Inhibition of Stat3 increases doxorubicin sensitivity in a human metastatic breast cancer cell line.

Metastatic breast cancer is an incurable disease, often characterized by poor response to standard chemotherapy, which is mainly based on anthracyclines and taxanes. Thus, increasing tumor cell sensitivity to these agents is an attractive goal towards improving the clinical management of this disease. The present study investigates the effects of signal transducer and activator of transcription 3 (Stat3) inhibition on the response of the highly metastatic MDA-MB-231 human breast adenocarcinoma cell line to doxorubicin (DOX).

The nitroxide Tempol modulates anthracycline resistance in breast cancer cells.

The occurrence of multidrug resistance (MDR) is the major obstacle to successful anthracycline-based cancer chemotherapy. In the present study, we assessed the effects of Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, TPL), a piperidine nitroxide with growth-inhibitory properties in tumor cell lines, on a number of molecular mechanisms involved in the resistance of human breast adenocarcinoma cell lines to doxorubicin (DOX). Cytotoxicity studies in MCF-7 wildtype and their MDR variant MCF-7 Adr(R) cells showed a synergistic effect between TPL and DOX when exposure to TPL preceded or was simultaneous with DOX treatment in MCF-7 Adr(R) cells.

Role of the p53/p21 system in the response of human colon carcinoma cells to Doxorubicin.

Background: Colon adenocarcinomas are refractory to a number of widely used anticancer agents. Multifactorial mechanisms have been implicated in this intrinsically resistant phenotype, including deregulation of cell death pathways. In this regard, the p53 protein has a well established role in the control of tumor cell response to DNA damaging agents; however, the relationship between p53-driven genes and drug sensitivity remains controversial.

The piperidine nitroxide Tempol potentiates the cytotoxic effects of temozolomide in human glioblastoma cells.

Temozolomide (TMZ) is a methylating agent with promising antitumor efficacy for the treatment of melanomas and intermediate-grade gliomas. Unfortunately, its use in the management of high-grade gliomas (glioblastomas) is limited by multifaceted resistance mechanisms. The aim of this study was to evaluate the possibility to improve the cytotoxic response of two human glioblastoma cell lines, U87MG and U373MG, to TMZ by the use of Tempol (TPL), a low molecular weight piperidine nitroxide that has been shown to inhibit in vitro and in vivo growth of murine glioma cells.

Photodynamic effects of porphyrin and chlorin photosensitizers in human colon adenocarcinoma cells.

Photodynamic therapy (PDT) is a cancer treatment involving systemic administration of a tumor-localizing photosensitizer; this, when activated by the appropriate wavelength of light, interacts with molecular oxygen to form a toxic, short-lived species known as singlet oxygen, which is thought to mediate cellular death. Photofrin, a complex mixture of porphyrin oligomers has recently received FDA approval for the photodynamic treatment of esophageal and endobronchial carcinoma, but its photodynamic and toxicity profiles are far from ideal. In the present study we evaluated a series of porphyrin-based PSs, some of which newly synthesized by our group, with the aim to identify agents with more favorable characteristics.

Molecular determinants of intrinsic resistance to doxorubicin in human cancer cell lines.

Intrinsic or acquired drug resistance poses a major challenge to the success of chemotherapy in the clinical management of human cancers. While acquired multidrug resistance (MDR), whereby cells become refractory to multiple drugs, has been extensively investigated, the mechanistic basis for intrinsic resistance remains elusive, so that this condition is largely unmanageable in the clinical setting. To address this issue, we have assessed the effects of the anticancer agent doxorubicin (DX) on a panel of human tumor cell lines originally derived from untreated patients and tried to establish a correlation between cell response and a number of parameters, including drug accumulation and/or drug efflux; differences in expression and/or subcellular distribution of proteins involved in the apoptotic process (e.