RESUMO
We studied the synergistic effects of hyperthermia and anticancer drugs on induction of apoptosis in lung cancer cells (LK-2 and LU-65A) using in situ end-labeling of DNA, the DNA fragmentation assay, and transmission electron microscopy. A few apoptotic cells were detected only when both cell lines were heated at relatively high temperature (44 degrees C). Moderate numbers of apoptotic cells were observed when both cell lines were incubated with high concentrations (30 or 40 microM) of anticancer drug. Compared with hyperthermia or anticancer drug alone, the combined treatment induced many apoptotic cells in both cell lines, even in the cells treated with lower concentrations (6 or 8 microM) of anticancer drugs following mild hyperthermia (43 degrees C). In regard to kinetics of apoptotic cells induced by treatment, the maximum induction of apoptosis by the combined treatment was higher than that of hyperthermia or anticancer drug alone in both cell lines, although the time of the peak of apoptotic index differed among the three treatments. Therefore, "hyperthermo-chemotherapy" may reduce the required dosage of anticancer drug and decrease the temperature of hyperthermia on induction of apoptosis.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Temperatura Alta , Cisplatino/farmacologia , Etoposídeo/farmacologia , Humanos , Hipertermia Induzida , Células Tumorais CultivadasRESUMO
Southern blot analysis with a cDNA probe of MLL indicated that the breakpoint is in a BamHI 8.3 kb fragment which carries the exon 5-11 of MLL gene in DNA from an adult acute myelomonocytic leukaemia with a t(11;22) (q23;q11) translocation. The structural analysis of the rearranged MLL locus demonstrated that the breakpoint is localized between exon 8 and 9 of MLL locus. The normal counterpart fused to the MLL locus was proved to be derived from chromosome 22q11(AF-22) by somatic cell hybrids analysis and FISH. By FISH, AF-22 was localized to the region more centromeric to the BCR gene.
Assuntos
Cromossomos Humanos Par 11 , Cromossomos Humanos Par 22 , Leucemia Mielomonocítica Aguda/genética , Proteínas Tirosina Quinases , Proteínas Proto-Oncogênicas , Translocação Genética , Adulto , Northern Blotting , Southern Blotting , Clonagem Molecular , Humanos , Hibridização in Situ Fluorescente , Masculino , Proteínas Oncogênicas/genética , Proteínas Proto-Oncogênicas c-bcrRESUMO
Expression of the RCK gene, which is a target gene on 11q23 of the t(11;14) (q23;q32) translocation in the B-cell lymphoma cell line RC-K8, was studied by Northern and Western blot analyses. The RCK gene product is a member of the D-E-A-D box protein/RNA helicase family. With the use of Northern blot analysis, a 7.5-kb transcript of the RCK gene was shown to be expressed ubiquitously in human and mouse tissues. Polyclonal antibodies against the RCK gene product were raised, and the RCK gene expression pattern was examined in human and mouse tissues. Two different polyclonal anti-rck antibodies detected a specific 54-kilodalton product named rck/p54 in the majority of human and mouse tissues tested by Western blot analysis. However, rck/p54 was shown to be very low in the human brain and was not detectable in lumbar muscle and lung tissues, although RCK mRNA is abundantly present in these tissues. It is of interest that malignant transformed human cells arising from tissues with low or no expression of rck/p54, such as neuroblastoma, glioblastoma, rhabdomyosarcoma, and lung cancer cell lines, produced a moderate amount of rck/p54 protein, suggesting that rck/p54 plays a role in tumorigenesis. In addition, the rck/p54 protein was localized to cytoplasm by immunostaining with the use of laser microscopy and by subcellular fractionation.
