G2 accumulation and melanin overproduction in malignant melanocytes treated with a new nitrosourea

Buchdahl, Catherine; Papon, Janine; Communal, Y; Bourgès, M; Madelmont, Jean‐Claude

doi:10.1097/00008390-199812000-00007

Cited by 5 publications

(4 citation statements)

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“…A few days after cystemustine treatment, cultured B16 melanoma cells exhibit blockage in the G2 phase. After 2 weeks they exit the G2 phase, cross the M phase, and enter the G1 phase again, while progressively losing synchronization (26). Our NMR observations may be explained in part by the progression of the cultured cells through the cell cycle after they were blocked in the G2 phase.…”

Section: Plp Metabolism Alterations Under Cenu Treatmentmentioning

confidence: 60%

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Quantitative HRMAS proton total correlation spectroscopy applied to cultured melanoma cells treated by chloroethyl nitrosourea: Demonstration of phospholipid metabolism alterations

Morvan

Demidem

Papon

et al. 2003

Magnetic Resonance in Med

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The ability to follow phospholipid (Plp) metabolism is of paramount importance in many circumstances in which cell survival and cell proliferation are of concern-for example in neurological disorders and cancer (1,2). NMR spectroscopy has long been known to be important tool for exploring Plp metabolism (3-6). Novel NMR developments, such as high-resolution magic angle spinning (HRMAS) probes, have provided improved spectra of cultured cells (7) and normal (8,9) and cancer (10 -12) tissues. Recently, using HRMAS together with proton total correlation spectroscopy (TOCSY), we showed that a mousebearing B16 melanoma tumor responded to chloroethyl nitrosourea (CENU) treatment in vivo by altering its Plp metabolism (12).The first purpose of the present study was to demonstrate on cultured B16 melanoma cells in vitro that HRMAS proton TOCSY cross-peak signal variations of Plp derivatives reflected concentration variations. The second purpose was to determine the Plp metabolism response of cultured B16 melanoma cells to CENU treatment in vitro, as a model for Plp metabolism alterations previously observed in vivo.The Plp derivatives that were simultaneously observed using proton TOCSY were choline (Cho), phosphocholine (PC), cytidyl-diphosphate-choline (CDP-Cho), ethanolamine (Eth), phosphoethanolamine (PE), CDP-ethanolamine (CDP-Eth) (all of which are derivatives of the phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEth) biosynthetic pathways), and glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE) (derivatives of PtdCho and PtdEth hydrolysis) (1-3).As regards the most expressed Plp derivatives in cultured B16 melanoma cells, HRMAS proton TOCSY signals revealed linearity with 1D saturation recovery signals, the NMR spectroscopy reference for quantifying concentrations. Therefore, HRMAS proton TOCSY was used to quantify concentration changes of water-soluble Plp derivatives in CENU-treated cultured melanoma cells. The response of cultured B16 melanoma cells to CENU treatment involved a transient accumulation of GPC and GPE, a down-regulation of PC and increase of CDP-Eth during cell proliferation inhibition, and a dramatic and irreversible rise of PE during and after cell proliferation inhibition. These data are discussed in relation to mouse-bearing B16 melanoma tumor response to CENU in vivo, and to Plp metabolism enzymatic involvement. METHODS ChemicalsNЈ-[2-chloroethyl]-N[2-(methylsulfonyl)ethyl]-NЈ-nitrosourea (cystemustine) is a CENU antineoplastic agent (13) that has been proposed for the treatment of human malignant melanoma and glioma. Cystemustine (Orphachem, Clermont-Ferrand, France) was supplied as a 5-mM solution in 0.9% NaCl. D 2 O (SDS, Peypin, France) was used to lock the spectrometer. Cell CulturesTransplantable B16 melanoma cells originating from C57BL6/6J Ico mice (ICIG, Villejuif, France) were adapted

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Section: Plp Metabolism Alterations Under Cenu Treatmentmentioning

confidence: 60%

“…Cystemustine is known to produce DNA damage (13) and induce growth arrest but not apoptosis in B16 melanoma (26,27). A few days after cystemustine treatment, cultured B16 melanoma cells exhibit blockage in the G2 phase.…”

Section: Plp Metabolism Alterations Under Cenu Treatmentmentioning

confidence: 99%

Quantitative HRMAS proton total correlation spectroscopy applied to cultured melanoma cells treated by chloroethyl nitrosourea: Demonstration of phospholipid metabolism alterations

Morvan

Demidem

Papon

et al. 2003

Magnetic Resonance in Med

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“…Cell morphology, cell cycle distribution, nuclear aberrations, DNA damage and metabolism alterations of these cells during the GI and the GR phases have been previously reported (11)(12)(13)(22)(23)(24). These cells demonstrated decreased aggressiveness and redifferentiation during both phases: accumulation in G 1 phase of the cell cycle during the growth GR phase, increased pool of PUFA, acquired metabolic alteration (phospholipid, methionine, energetic metabolism), decreased pool of glutathione (11)(12)(13)(22)(23)(24). It has been reported that the methylation of PP2A catalytic subunit was the most important methyl group consumer among the cellular proteins (14,17,25).…”

Section: Resultsmentioning

confidence: 89%

PP2A activity is controlled by methylation and regulates oncoprotein expression in melanoma cells: A mechanism which participates in growth inhibition induced by chloroethylnitrosourea treatment

Guenin

Schwartz²,

Morvan³

et al. 2008

Int J Oncol

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Abstract. Protein phosphatase 2A (PP2A), an Akt pathway inhibitor, is considered to be activated by methylation of its catalytic subunit. Also PP2A downregulation was proposed to take part in carcinogenesis. Recently, PP2A activation was shown to be activated in response to DNA damage. To obtain further information on the role of PP2A in tumors and response to DNA damage, we investigated the relationship between PP2A methylation and activity, cell proliferation, Akt activation, c-Myc expression and PTEN activity in B16 melanoma cells untreated and after chloroethylnitrosourea (CENU) treatment. In untreated cells, okadaic acid, an antagonist of PP2A methylation, inhibited PP2A activity, stimulated cell proliferation, increased Akt activation and c-Myc expression. Xylulose-5-phosphate, an agonist of PP2A methylation, increased PP2A activity, decreased cell proliferation, Akt activation and c-Myc expression. However, both PP2A methylation modulators increased PTEN activity. During the response to CENU treatment, PP2A methylation and activity were strongly increased, Akt activation and c-Myc expression were decreased. However PTEN activity was increased. After tumor cell growth recovery, these modifications were moderately decreased. PP2A methylation was quantified and correlated positively with PP2A activity, and negatively with criteria for cell aggressiveness (cell proliferation, Akt activation, c-Myc expression). Based on these data, PP2A methylation status controls PP2A activity and oncoproteins expression and PP2A is strongly activated after CENU treatment thus partly explaining the growth inhibition in response to this agent. It follows that PP2A promethylating agents are potential candidates for anticancer drugs.

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“…However, CENUs are unstable molecules under physiological conditions and break into reactive entities, isocyanate and chloroethyl carbocation with multiple cytotoxic properties able to cause disorders in many cellular functions with varying degrees. Besides DNA damage, CENU treatment of B16 melanoma cells induced growth arrest in the G 2 phase and stimulated the expression of differentiation markers such as increased tyrosinase activity and enhanced melanin production 6, 7. Cell survival was linked to alteration of the phospholipid metabolism 8, 9.…”

Section: Introductionmentioning

confidence: 99%

Mitochondrial bioenergetic background confers a survival advantage to HepG2 cells in response to chemotherapy

Loiseau

Morvan

Chevrollier

et al. 2009

Molecular Carcinogenesis

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Cancer cells mainly rely on glycolysis for energetic needs, and mitochondrial ATP production is almost inactive. However, cancer cells require the integrity of mitochondrial functions for their survival, such as the maintenance of the internal membrane potential gradient (DeltaPsim). It thus may be predicted that DeltaPsim regeneration should depend on cellular capability to produce sufficient ATP by upregulating glycolysis or recruiting oxidative phosphorylation (OXPHOS). To investigate this hypothesis, we compared the response to an anticancer agent chloroethylnitrosourea (CENU) of two transformed cell lines: HepG2 (hepatocarcinoma) with a partially differentiated phenotype and 143B (osteosarcoma) with an undifferentiated one. These cells types differ by their mitochondrial OXPHOS background; the most severely impaired being that of 143B cells. Treatment effects were tested on cell proliferation, O(2) consumption/ATP production coupling, DeltaPsim maintenance, and global metabolite profiling by NMR spectroscopy. Our results showed an OXPHOS uncoupling and a lowered DeltaPsim, leading to an increased energy request to regenerate DeltaPsim in both models. However, energy request could not be met by undifferentiated cells 143B, which ATP content decreased after 48 h leading to cell death, while partially differentiated cells (HepG2) could activate their oxidative metabolism and escape chemotherapy. We propose that mitochondrial OXPHOS background confers a survival advantage to more differentiated cells in response to chemotherapy. This suggests that the mitochondrial bioenergetic background of tumors should be considered for anticancer treatment personalization.

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G2 accumulation and melanin overproduction in malignant melanocytes treated with a new nitrosourea

Cited by 5 publications

References 0 publications

Quantitative HRMAS proton total correlation spectroscopy applied to cultured melanoma cells treated by chloroethyl nitrosourea: Demonstration of phospholipid metabolism alterations

Quantitative HRMAS proton total correlation spectroscopy applied to cultured melanoma cells treated by chloroethyl nitrosourea: Demonstration of phospholipid metabolism alterations

PP2A activity is controlled by methylation and regulates oncoprotein expression in melanoma cells: A mechanism which participates in growth inhibition induced by chloroethylnitrosourea treatment

Mitochondrial bioenergetic background confers a survival advantage to HepG2 cells in response to chemotherapy

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