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Antiproliferative and differentiating effects of benzodiazepine receptor ligands on B16 melanoma cells
M Landau1, A Weizman, E Zoref-Shani
1Laboratory of Biochemistry and Pharmacology of Cancer Cells, Felsenstein Medical Research Center, Petach Tikva, Israel.
Abstract:
In this study, we evaluated the effect of several ligands active at the central-type and peripheral-type benzodiazepine receptor (BzR) (clonazepam, diazepam, PK11195 and Ro5-4864) on the growth and differentiation of B16 melanoma cells. All tested BzR ligands were able to suppress proliferation of the cells at the micromolar range and in a concentration-dependent manner. However, agents selectively active at the peripheral-type BzR (PK11195 and Ro5-4864) exhibited more potent antiproliferative activity. In addition, the BzR ligands were demonstrated to affect the cell cycle by reducing the percent of cells in the S phase and increasing the percent in the G2/M phase. BzR ligands induced cellular phenotypic alterations, which have been previously shown to be associated with melanoma cell differentiation. These alterations included: marked morphological changes, enhancement of melanogenesis, lipid accumulation and increase in the activity of gamma glutamyl transpeptidase. All BzR ligands induced a marked reduction in the concentration of UTP and most of them did the same in GTP and CTP, while ATP levels were not significantly altered. In summary, BzR ligands (clonazepam, diazepam, PK11195 and Ro5-4864) were found to exert antitumor effects in B16 melanoma cells. These findings encourage further studies of a possible therapeutic potential of BzR ligands in treatment of melanoma.
Insights
Benzodiazepine receptor (BzR) ligands suppressed B16 melanoma cell proliferation and induced differentiation. Peripheral-type BzR ligands showed greater antiproliferative effects, suggesting potential therapeutic applications for melanoma treatment.
Area of Science:
- Pharmacology
- Cancer Biology
- Cell Biology
Background:
- Benzodiazepine receptors (BzRs) are implicated in various physiological processes.
- The role of BzRs in melanoma cell growth and differentiation is not fully understood.
Purpose of the Study:
- To investigate the effects of central-type and peripheral-type BzR ligands on B16 melanoma cell proliferation and differentiation.
- To explore the potential therapeutic value of BzR ligands in melanoma treatment.
Main Methods:
- Treatment of B16 melanoma cells with various BzR ligands (clonazepam, diazepam, PK11195, Ro5-4864).
- Assessment of cell proliferation, cell cycle distribution, and phenotypic differentiation markers.
- Analysis of intracellular nucleotide triphosphate (ATP, GTP, CTP, UTP) levels.
Main Results:
- All tested BzR ligands suppressed melanoma cell proliferation in a concentration-dependent manner.
- Peripheral-type BzR ligands (PK11195, Ro5-4864) demonstrated more potent antiproliferative activity.
- BzR ligands induced cell cycle arrest in G2/M phase, promoted differentiation markers (morphological changes, melanogenesis, GGT activity), and altered nucleotide triphosphate levels.
Conclusions:
- BzR ligands exhibit significant antitumor effects against B16 melanoma cells.
- Peripheral-type BzR ligands warrant further investigation for melanoma therapy.
- BzR modulation represents a promising avenue for melanoma treatment development.