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Effects of C2-ceramide on the Malme-3M melanoma cell line
Won Suk Han1, Jong Yeop Yoo, Sang Woong Youn
1Department of Dermatology, Seoul National University Hospital, 28, Youngon-Dong, Chongno-Gu, 110-744, Seoul, South Korea.
Abstract:
Ceramide is implicated in the regulation of various signaling pathways leading to proliferation, differentiation or apoptotic cell death, but there have been few investigations about the effects of ceramide on the cell growth and the melanogenesis of melanocytes. In the present study, we investigated the effects of cell-permeable ceramide on Malme-3M human melanoma cell line. MTT proliferation assay showed that C2-ceramide inhibited the growth of Malme-3M cells in a dose-dependent manner. Cell cycle analysis confirmed the inhibition of DNA synthesis by a reduction in the S phase and an increase in the G0/G1 phase. Flow cytometric analysis for apoptotic cells and morphological observations indicated that the antiproliferative effect of C2-ceramide was not due to apoptosis. We next investigated the effects of C2-ceramide on the pigmentation of Malme-3M melanoma cells. The results showed that C2-ceramide induced only a slight decrease of tyrosinase activity and melanin synthesis. To investigate the ceramide signaling pathway, we studied the influence of C2-ceramide on extracellular signal-regulated kinase (ERK) and Akt activation by Western blot. We demonstrated that the amount of phosphorylated Akt was decreased by C2-ceramide, whereas ERK was activated transiently. Because of a well-known involvement of ceramide in apoptosis, we further investigated the level of caspase-3 and HSP70 after treatment of C2-ceramide. We found that the caspase-3 was not activated and the expression of HSP70 increased moderately. In conclusion, C2-ceramide inhibited the cell growth of Malme-3M cells without the induction of apoptosis. We suggest that increased HSP70 may be related to the resistance against apoptosis.
Insights
Cell-permeable ceramide (C2-ceramide) inhibits human melanoma cell growth by halting DNA synthesis and increasing G0/G1 phase, without inducing apoptosis. Increased HSP70 expression may contribute to this resistance.
Area of Science:
- Cell Biology
- Biochemistry
- Dermatology
Background:
- Ceramides regulate cell proliferation, differentiation, and apoptosis.
- Limited research exists on ceramide's effects on melanocyte growth and melanogenesis.
Purpose of the Study:
- Investigate the impact of cell-permeable ceramide on human melanoma cell line Malme-3M.
- Determine ceramide's effects on cell growth, cell cycle, apoptosis, melanogenesis, and key signaling pathways.
Main Methods:
- MTT proliferation assay to assess cell viability.
- Cell cycle analysis and flow cytometry for apoptosis detection.
- Western blot to analyze ERK and Akt activation, and caspase-3 and HSP70 levels.
Main Results:
- C2-ceramide inhibited Malme-3M cell growth in a dose-dependent manner.
- Cell cycle analysis revealed reduced S phase and increased G0/G1 phase, indicating inhibited DNA synthesis.
- Apoptosis was not induced; instead, HSP70 expression increased moderately, suggesting a role in apoptosis resistance.
- Tyrosinase activity and melanin synthesis showed only slight decreases.
- Akt phosphorylation decreased, while ERK activation was transient.
Conclusions:
- C2-ceramide effectively inhibits Malme-3M melanoma cell growth without inducing apoptosis.
- The observed increase in HSP70 may be linked to the cells' resistance to apoptosis.
- Ceramide's signaling pathway involves modulation of Akt and ERK, impacting cell proliferation.