Effects of heat stress on the level of heat shock protein 70 on the surface of hepatocellular carcinoma Hep G2 cells: implications for the treatment of tumors.

The ability to distinguish tumor cells from normal cells is vital to allow the immune system to selectively destroy tumor cells. In order to find an effective marker, we used enzyme-linked immunosorbent assay, immunocytochemistry, immunofluorescence, and flow cytometry to investigate the effects of heat stress on the amount of heat shock protein 70 on the surface of tumor cells (Hep G2 cells). Heat shock protein 70 is the major stress-induced heat shock protein found on the surface of tumor cells. Our results indicate that the percentage of Hep G2 cells with a detectable level of heat shock protein 70 on their cell surface increased significantly (P < 0.05) following heat stress at 42 °C for 2 h (up to 1.92 times the level before heat treatment). The detectable level of heat shock protein 70 on the surface of Hep G2 cells reached its peak 12 h after treatment. However, the fluorescent intensity of stressed and unstressed Hep G2 cells was not significantly different (P > 0.05). The increase in the level of heat shock protein 70 on the surface of tumor cells following heat stress could provide a basis for finding novel immunotoxins as targets for drug action and may have application to be used in conjunction with hyperthermia in the treatment of tumors.

Isolation and characterization of a "phiKMV-like" bacteriophage and its therapeutic effect on mink hemorrhagic pneumonia.

The objective of this study was to investigate the potential of using phages as a therapy against hemorrhagic pneumonia in mink both in vitro and in vivo. Five Pseudomonas aeruginosa (P. aeruginosa) strains were isolated from lungs of mink with suspected hemorrhagic pneumonia and their identity was confirmed by morphological observation and 16S rDNA sequence analysis. Compared to P. aeruginosa strains isolated from mink with hemorrhagic pneumonia in 2002, these isolates were more resistant to antibiotics selected. A lytic phage vB_PaeP_PPA-ABTNL (PPA-ABTNL) of the Podoviridae family was isolated from hospital sewage using a P. aeruginosa isolate as host, showing broad host range against P. aeruginosa. A one-step growth curve analysis of PPA-ABTNL revealed eclipse and latent periods of 20 and 35 min, respectively, with a burst size of about 110 PFU per infected cell. Phage PPA-ABTNL significantly reduced the growth of P. aeruginosa isolates in vitro. The genome of PPA-ABTNL was 43,227 bp (62.4% G+C) containing 54 open reading frames and lacked regions encoding known virulence factors, integration-related proteins and antibiotic resistance determinants. Genome architecture analysis showed that PPA-ABTNL belonged to the "phiKMV-like Viruses" group. A repeated dose inhalational toxicity study using PPA-ABTNL crude preparation was conducted in mice and no significantly abnormal histological changes, morbidity or mortality were observed. There was no indication of any potential risk associated with using PPA-ABTNL as a therapeutic agent. The results of a curative treatment experiment demonstrated that atomization by ultrasonic treatment could efficiently deliver phage to the lungs of mink and a dose of 10 multiplicity of infection was optimal for treating mink hemorrhagic pneumonia. Our work demonstrated the potential for phage to fight P. aeruginosa involved in mink lung infections when administered by means of ultrasonic nebulization.