No abstract

Glucocorticoids (GCs) such as dexamethasone (DEX) have been widely used as co-medication in cancer therapy because they have potent proapoptotic properties in lymphoid cells, can reduce nausea, and alleviate acute toxic effects in healthy tissue. However, GCs are used in a supportive-care role, even though no prospective clinical studies have assessed the effect of these steroids on the growth of solid tumours. Data from preclinical and, to some extent, clinical studies, suggest that GCs induce treatment resistance in some solid tumours. Since it is unknown whether GC-induced resistance occurs only occasionally or is a more common phenomenon, we performed a screening study using several established cell lines from bone, brain, breast and cervix carcinoma as well as melanoma and neuroblastoma together with fresh surgical resections from patients with breast cancer. We found that DEX inhibits cisplatin and 5fluorouracil-induced apoptosis and promotes the growth of the majority of examined malignant cells. In contrast, and as expected, DEX acted pro-apoptotically and promoted the cytotoxic effect of chemotherapy in established and primary lymphoid cells. Thus, these data demonstrate the need for detailed molecular studies to clarify the mechanism of differential glucocorticoid signaling as well as controlled, prospective clinical studies.

Real-time imaging of multiple low-abundance microRNAs (miRNAs) simultaneously in living cells with high sensitivity is of vital importance for accurate cancer clinical diagnosis and prognosis studies. Maintaining stability of nanoprobes resistant to enzyme degradation and enabling effective signal amplification is highly needed for in vivo imaging studies. Herein, a rationally designed one-pot assembled multicolor tetrahedral DNA frameworks (TDFs) by encoding multicomponent nucleic acid enzymes (MNAzymes) was developed for signal-amplified multiple miRNAs imaging in living cells with high sensitivity and selectivity. TDFs could enter cells via self-delivery with good biocompatibility and stability. Two kinds of MNAzymes specific for miRNA-21 and miRNA-155 with fluorescein labeling were encoded in the structure of TDFs respectively through one-step thermal annealing. In the intracellular environment, the TDFs could be specifically bound with its specific miRNA target and form an active DNAzyme structure. The cleavage of the active site would trigger the release of target miRNA and circular fluorescence signal amplification, which enabled accurate diagnosis on miRNA identifications of different cell lines with high sensitivity. Meanwhile, with the specific AS1411 aptamer targeting for nucleolin overexpressed on the surface of the carcinoma cells, this well-designed TDFs nanoprobe exhibited good discrimination between cancer cells and normal cells. The strategy provides an efficient tool for understanding the biological function of miRNAs in cancer pathogenesis and therapeutic applications.

BackgroundInfectious bronchitis virus (IBV) is the coronavirus of domestic chickens causing major economic losses to the poultry industry. Because of the complexity of the IBV life cycle and the small number of viral structural proteins, important virus-host relationships likely remain to be discovered. Toward this goal, we performed two-dimensional gel electrophoresis fractionation coupled to mass spectrometry identification approaches to perform a comprehensive proteomic analysis of purified IBV particles.ResultsApart from the virus-encoded structural proteins, we detected 60 host proteins in the purified virions which can be grouped into several functional categories including intracellular trafficking proteins (20%), molecular chaperone (18%), macromolcular biosynthesis proteins (17%), cytoskeletal proteins (15%), signal transport proteins (15%), protein degradation (8%), chromosome associated proteins (2%), ribosomal proteins (2%), and other function proteins (3%). Interestingly, 21 of the total host proteins have not been reported to be present in virions of other virus families, such as major vault protein, TENP protein, ovalbumin, and scavenger receptor protein. Following identification of the host proteins by proteomic methods, the presence of 4 proteins in the purified IBV preparation was verified by western blotting and immunogold labeling detection.ConclusionsThe results present the first standard proteomic profile of IBV and may facilitate the understanding of the pathogenic mechanisms.

The glucocorticoid dexamethasone is frequently used as a co-treatment in cytotoxic cancer therapy, e.g. to prevent nausea, to protect normal tissue or for other reasons. While the potent pro-apoptotic properties and supportive effects of glucocorticoids to tumour therapy in lymphoid cells are well studied, the impact on the cytotoxic treatment of ovarian carcinoma is unknown. We tested apoptosisinduction, viability, tumour growth and protein expression using established cell lines, primary cell lines freshly isolated from patient material and a xenograft on nude mice. We found a general induction of resistance toward cytotoxic therapy by DEX-co-treatment in most of the examined ovarian cancer cells treated in vitro, ex vivo or in vivo. Resistance occured independently of cell density and was found at peak plasma levels of dexamethasone and below. Mechanistically, the dexamethasone-induced expression of survival genes may be involved in the resistance. These data show that glucocorticoid-induced resistance is common in ovarian carcinomas implicating that the use of glucocorticoids may be harmful for cancer patients.

No abstract

Raltitrexed has shown efficacy and safety in many tumor types; however, the clinical data on the treatment of hepatocellular carcinoma is rare. In this report, we aim to assess the efficacy and safety of raltitrexed plus oxaliplatin (OXA)-based transarterial chemoembolization (TACE) in patients with unresectable hepatocellular carcinoma (uHCC). Patients with uHCC were recruited from multi-centers in China and assigned randomly to raltitrexed+OXA-based (n=76), fluorouracil+OXA-based (n=76), and doxorubicin+OXA-based (n=75) TACE treatment. The primary end point was overall survival (OS). Tumor response was assessed using response evaluation criteria in solid tumors (RECIST), modified response evaluation criteria in solid tumors (mRECIST), and European Association for the Study of the Liver criteria (EASL). Safety and toxicity were evaluated using the National Cancer Institute Common Toxicity Criteria. The raltitrexed group showed a better disease control rate evaluated using RECIST (raltitrexed vs. fluorouracil vs. doxorubicin: 96.1 vs. 84.2 vs. 86.7%, P=0.05) and a better overall response rate on the basis of mRECIST (67.1 vs. 47.4 vs. 50.7%, P=0.03) and EASL (67.1 vs. 47.4 vs. 49.3%, P=0.02). The median OS and median progression-free survival (PFS) were higher in the raltitrexed group (median OS: 13.4 vs. 9.6 vs. 8.5 months; median PFS: 6.7 vs 4.9 vs 4.6 months). The most common toxicities included elevated aspartate aminotransferase (78.9 vs. 86.8 vs. 81.3%) and abdominal nonspecific pain (68.4 vs. 81.6 vs. 78.7%). No significant differences were found in the overall number of patients who experienced any toxicity. Raltitrexed plus OXA-based TACE suggested a safe and efficacious regimen in uHCC patients. The results warrant further clinical investigation.

These data show that DEX induces therapy resistance in pancreatic carcinoma cells and raise the question whether GC-mediated protection of tumour cells from cancer therapy may be dangerous for patients.