title: Gene expression profiles in human malignant melanoma cell lines exposed to carbon ions or X-rays

status: Public on Jun 01 2008

city: Chiba-shi

first: Yoshitaka

last: Matsumoto

address: 4-9-1, Anagawa, Inage-ku

department: Research Center for Charged Particle Therapy

institute: National Institute of Radiological Sciences

summary:
Little is known about molecular mechanism for its effectiveness of C-ions in melanomas. In this study, we examined the cytotoxic effects of C-ions on 6 human malignant melanoma cell lines, and gene expression profiles and cell cycle progression were also examined to reveal the mechanism of the therapeutic effectiveness of C-ions.
Equivalent doses of the C-ions were more effective at reducing the survival rates than X-rays, and the relative biological effectiveness (RBE) was > 2.0 in all cell lines.
In unsupervised 2D clustering performed for C-ions irradiated groups at 1 h after irradiation, many of the probes were down-regulated among 6 cell lines.
We identified probes, such as XKRY, ELA3A, T-STAR, SCN9A, ELA2A, CRK7, CCNA2, CROP, CYR61, SDFR1, and SMAD4 differentially responded to C-ions and X-rays among 4 cell lines. CCNA2 was down-regulated by C-ions more than X-rays at 3 h after irradiation, and C-ions induced G2/M arrest more than X-rays in three cell lines at 30 h.
Many of p53 target genes, such as ATF3, BTG2, CDKN1A, GADD45A, SESN1, and TNFRSF6 were up-regulated by C-ions at 3 h.
The expressions of p53 target genes were not changed in HMV-I and MeWo. In MeWo, APG3L, RPL26 and PCNA were down-regulated or E2F2 and LIMS3 were up-regulated, and in HMV-I, ATF3, FOS, and CYR61 were up-regulated at 1 h after C-ions.
In conclusion, C-ions affected p53-dependent and p53-independent pathways of cell death and cell cycle. Individual mechanism in activating of cell death was observed in each cell line of 6 melanomas.
Keywords: Specific gene expression prfiles after carbon ion irradiation

overall_design: To study the gene expression profiles in human melanoma cell lines exposed to carbon ions or X-rays. We used 6 cell lines, 92-1, C32TG, Colo679, HMV-I, HMV-II, and MeWo. Cells were irradiated with 2Gy of carbon ions or X-rays, and total RNA was extracted. We used human whole genome array (55k).

first: Mayumi

last: Iwakawa

first: Yoshiya

last: Furusawa

first: Kenichi

last: Ishikawa

first: Kaori

last: Imadome

first: Izumi

first: Hirohiko

last: Tsujii

first: Koichi

last: Ando

first: Takashi

last: Imai


title: CCRF-CEM Prednisolone and  MG132 treatments at 4h

status: Public on May 11 2011

city: Athens

first: George

middle: I

last: Lambrou

state: Attiki

address: Thivon & Levadeias

department: First Department of Pediatrics

country: Greece

institute: National and Kapodistrian University of Athens

summary:
Background: The combination of Proteasome inhibitor with Glucocorticoid is one of the most promising antileukemic treatments. Both agents act through pluripotent signal mediators. The two types of agents inhibit key signals that are considered crucial to their effects on malignant cells.
Methodology/Principal Findings: Combined use of the two reagents on the lymphoblastic leukemia cell line CCRF-CEM has a range of effects on the viability that depend on the dose and the time used. Even though both reagents are capable of enhancing cell death on the CEM cell line, no combinatorial increase in cell death is detectable, until after the first 120 hours of treatment.  In contrast, there are a number of combinatorial effects on the cell cycle phase distribution of treated cells, which indicates a potential for mutual signal disruption between glucocorticoid and proteasome inhibitor at multiple levels. Microarray analysis indicates that Prednisolone and MG132 elicit highly divergent, early-response molecular signatures on this cell line. We assayed levels of the antiapoptotic protein Mcl-1 as a potential model of late, downstream target regulation by both glucocorticoid and proteasome. Synchronized use of Prednisolone with MG132 results in temporary stabilization of Mcl-1 in CEM cells. Stabilization is not the result of a common mechanism of action on the genome, as Prednisolone and MG132 elicit nonreduntant molecular signatures, and it occurs also when the cells are treated at different timepoints with either agent.
Conclusions/Significance: Our results show that this glucocorticoid-resistant ALL lymphoblast line is highly sensitive to proteasome inhibitor, and suggest that the proteasome inhibitor and the glucocorticoid regulate different direct target genes. This difference in immediate targets, when the two agents are applied in combination, may lead to negative or positive interference with mechanisms regulating viability of the leukemic lymphoblast. Signal interference between glucocorticoid Prednisolone and the proteasome inhibitor MG132 is expected to occur at more than one level, resulting in complex effects on intracellular signal transduction pathways. The net result depends on the development of individual downstream effects and interactions between key signal mediators. Elucidation of the conditions of interference between glucocorticoid and proteasome targets on leukemic cell fate is expected to improve effects of applied treatment combinations.

overall_design: Experimental setups consisted of the three following samples obtained after 4 h treatment: control, 10nM prednisolone, 1uM prednisolone, 10uM prednisolone, 100μM prednisolone, 700μM prednisolone, 200nM MG132, 2μM MG132 and 20μM MG132. Untreated cells were used as reference.