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Lipid raft-mediated Akt signaling as a therapeutic target in mantle cell lymphoma.

Reis-Sobreiro M, Roué G, Moros A, Gajate C, de la Iglesia-Vicente J, Colomer D, Mollinedo F - Blood Cancer J (2013)

Bottom Line: The antitumor lipids (ATLs) edelfosine and perifosine target rafts, and we found that ATLs exerted in vitro and in vivo antitumor activity against MCL cells by displacing Akt as well as key regulatory kinases p-PDK1 (phosphatidylinositol-dependent protein kinase 1), PI3K and mTOR (mammalian TOR) from lipid rafts.Microenvironmental stimuli, such as CD40 ligation or stromal cell contact, did not prevent ATL-induced apoptosis in MCL cell lines and patient-derived cells.These results highlight the role of raft-mediated PI3K/Akt signaling in MCL cell survival and chemotherapy, thus becoming a new target for MCL treatment.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología Molecular y Celular del Cáncer, Centro de Investigación del Cáncer, CSIC-Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.

ABSTRACT
Recent evidence shows that lipid raft membrane domains modulate both cell survival and death. Here, we have found that the phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway is present in the lipid rafts of mantle cell lymphoma (MCL) cells, and this location seems to be critical for full activation and MCL cell survival. The antitumor lipids (ATLs) edelfosine and perifosine target rafts, and we found that ATLs exerted in vitro and in vivo antitumor activity against MCL cells by displacing Akt as well as key regulatory kinases p-PDK1 (phosphatidylinositol-dependent protein kinase 1), PI3K and mTOR (mammalian TOR) from lipid rafts. This raft reorganization led to Akt dephosphorylation, while proapoptotic Fas/CD95 death receptor was recruited into rafts. Raft integrity was critical for Ser473 Akt phosphorylation. ATL-induced apoptosis appeared to correlate with the basal Akt phosphorylation status in MCL cell lines and primary cultures, and could be potentiated by the PI3K inhibitor wortmannin, or inhibited by the Akt activator pervanadate. Classical Akt inhibitors induced apoptosis in MCL cells. Microenvironmental stimuli, such as CD40 ligation or stromal cell contact, did not prevent ATL-induced apoptosis in MCL cell lines and patient-derived cells. These results highlight the role of raft-mediated PI3K/Akt signaling in MCL cell survival and chemotherapy, thus becoming a new target for MCL treatment.

No MeSH data available.


Related in: MedlinePlus

Effect of ATLs on JNK and ERK signaling, and PI3K inhibition enhances ATL-induced cell death in Z-138 cells. (a) Cells were untreated (control, C) or treated with 10 μℳ edelfosine for the indicated times, and then analyzed by immunoblotting for p-JNK, JNK, p-ERK and ERK2. (b) Cells were preincubated without (control, C) or with 1 μℳ SP600125 (SP) for 1 h, and then incubated in the absence or presence of 10 μℳ perifosine (P) or edelfosine (E) for 6 h, and analyzed by immunoblotting for p-JNK and JNK. (c) Cells were preincubated without or with 1 μℳ SP600125 (SP) for 1 h, and then incubated in the absence or presence of 10 μℳ edelfosine (EDLF) for 24 h. Apoptosis was then quantitated as the percentage of cells in the sub-G0/G1 region following cell cycle analysis by flow cytometry. Untreated control cells were run in parallel. (d) Cells were preincubated without or with 20 μℳ PD98059 (PD) for 1 h, and then incubated with 10 μℳ perifosine (PRIF) or edelfosine (EDLF) for 24 h. Cell viability was assessed as non-apoptotic cells in Annexin V-binding analysis by flow cytometry. Data are the means of two independent experiments performed. (e) Cells were pretreated without (control, C) or with 400 nℳ wortamnin (WN), and then incubated with 10 μℳ perifosine (P) or edelfosine (E) for 6 h and analyzed by immunoblotting for p-Akt (Ser473), Akt, p-mTOR and mTOR. (f) Cells were preincubated without or with 400 nℳ WN for 1 h, and then incubated in the absence or presence of 10 μℳ perifosine or edelfosine for 24 h, and analyzed by flow cytometry to evaluate apoptosis. Data shown are means±s.d. (**P<0.01) or representative blots of three independent experiments.
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fig2: Effect of ATLs on JNK and ERK signaling, and PI3K inhibition enhances ATL-induced cell death in Z-138 cells. (a) Cells were untreated (control, C) or treated with 10 μℳ edelfosine for the indicated times, and then analyzed by immunoblotting for p-JNK, JNK, p-ERK and ERK2. (b) Cells were preincubated without (control, C) or with 1 μℳ SP600125 (SP) for 1 h, and then incubated in the absence or presence of 10 μℳ perifosine (P) or edelfosine (E) for 6 h, and analyzed by immunoblotting for p-JNK and JNK. (c) Cells were preincubated without or with 1 μℳ SP600125 (SP) for 1 h, and then incubated in the absence or presence of 10 μℳ edelfosine (EDLF) for 24 h. Apoptosis was then quantitated as the percentage of cells in the sub-G0/G1 region following cell cycle analysis by flow cytometry. Untreated control cells were run in parallel. (d) Cells were preincubated without or with 20 μℳ PD98059 (PD) for 1 h, and then incubated with 10 μℳ perifosine (PRIF) or edelfosine (EDLF) for 24 h. Cell viability was assessed as non-apoptotic cells in Annexin V-binding analysis by flow cytometry. Data are the means of two independent experiments performed. (e) Cells were pretreated without (control, C) or with 400 nℳ wortamnin (WN), and then incubated with 10 μℳ perifosine (P) or edelfosine (E) for 6 h and analyzed by immunoblotting for p-Akt (Ser473), Akt, p-mTOR and mTOR. (f) Cells were preincubated without or with 400 nℳ WN for 1 h, and then incubated in the absence or presence of 10 μℳ perifosine or edelfosine for 24 h, and analyzed by flow cytometry to evaluate apoptosis. Data shown are means±s.d. (**P<0.01) or representative blots of three independent experiments.

Mentions: As JNK signaling has been involved in ATL-induced apoptosis40 and pathogenesis of MCL,42 and ERK activation has been described as a possible compensatory mechanism in Akt-compromised cells,43 we assessed the phosphorylation status of ERK and JNK in Z-138 cells exposed to edelfosine. As shown in Figure 2a, the level of p-JNK was dramatically increased during edelfosine exposure, whereas the p-ERK level was not modified during the first 9 h of treatment, and then decreased following the induction of apoptosis. However, despite p-JNK and p-ERK levels could be efficiently inhibited by JNK inhibitor SP600125 and ERK inhibitor PD98059, respectively (Figure 2b, and data not shown), these latter inhibitors did not significantly modify the cytotoxicity of ATLs, as assessed by hypodiploidy or Annexin V analyses (Figures 2c and d).


Lipid raft-mediated Akt signaling as a therapeutic target in mantle cell lymphoma.

Reis-Sobreiro M, Roué G, Moros A, Gajate C, de la Iglesia-Vicente J, Colomer D, Mollinedo F - Blood Cancer J (2013)

Effect of ATLs on JNK and ERK signaling, and PI3K inhibition enhances ATL-induced cell death in Z-138 cells. (a) Cells were untreated (control, C) or treated with 10 μℳ edelfosine for the indicated times, and then analyzed by immunoblotting for p-JNK, JNK, p-ERK and ERK2. (b) Cells were preincubated without (control, C) or with 1 μℳ SP600125 (SP) for 1 h, and then incubated in the absence or presence of 10 μℳ perifosine (P) or edelfosine (E) for 6 h, and analyzed by immunoblotting for p-JNK and JNK. (c) Cells were preincubated without or with 1 μℳ SP600125 (SP) for 1 h, and then incubated in the absence or presence of 10 μℳ edelfosine (EDLF) for 24 h. Apoptosis was then quantitated as the percentage of cells in the sub-G0/G1 region following cell cycle analysis by flow cytometry. Untreated control cells were run in parallel. (d) Cells were preincubated without or with 20 μℳ PD98059 (PD) for 1 h, and then incubated with 10 μℳ perifosine (PRIF) or edelfosine (EDLF) for 24 h. Cell viability was assessed as non-apoptotic cells in Annexin V-binding analysis by flow cytometry. Data are the means of two independent experiments performed. (e) Cells were pretreated without (control, C) or with 400 nℳ wortamnin (WN), and then incubated with 10 μℳ perifosine (P) or edelfosine (E) for 6 h and analyzed by immunoblotting for p-Akt (Ser473), Akt, p-mTOR and mTOR. (f) Cells were preincubated without or with 400 nℳ WN for 1 h, and then incubated in the absence or presence of 10 μℳ perifosine or edelfosine for 24 h, and analyzed by flow cytometry to evaluate apoptosis. Data shown are means±s.d. (**P<0.01) or representative blots of three independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3674457&req=5

fig2: Effect of ATLs on JNK and ERK signaling, and PI3K inhibition enhances ATL-induced cell death in Z-138 cells. (a) Cells were untreated (control, C) or treated with 10 μℳ edelfosine for the indicated times, and then analyzed by immunoblotting for p-JNK, JNK, p-ERK and ERK2. (b) Cells were preincubated without (control, C) or with 1 μℳ SP600125 (SP) for 1 h, and then incubated in the absence or presence of 10 μℳ perifosine (P) or edelfosine (E) for 6 h, and analyzed by immunoblotting for p-JNK and JNK. (c) Cells were preincubated without or with 1 μℳ SP600125 (SP) for 1 h, and then incubated in the absence or presence of 10 μℳ edelfosine (EDLF) for 24 h. Apoptosis was then quantitated as the percentage of cells in the sub-G0/G1 region following cell cycle analysis by flow cytometry. Untreated control cells were run in parallel. (d) Cells were preincubated without or with 20 μℳ PD98059 (PD) for 1 h, and then incubated with 10 μℳ perifosine (PRIF) or edelfosine (EDLF) for 24 h. Cell viability was assessed as non-apoptotic cells in Annexin V-binding analysis by flow cytometry. Data are the means of two independent experiments performed. (e) Cells were pretreated without (control, C) or with 400 nℳ wortamnin (WN), and then incubated with 10 μℳ perifosine (P) or edelfosine (E) for 6 h and analyzed by immunoblotting for p-Akt (Ser473), Akt, p-mTOR and mTOR. (f) Cells were preincubated without or with 400 nℳ WN for 1 h, and then incubated in the absence or presence of 10 μℳ perifosine or edelfosine for 24 h, and analyzed by flow cytometry to evaluate apoptosis. Data shown are means±s.d. (**P<0.01) or representative blots of three independent experiments.
Mentions: As JNK signaling has been involved in ATL-induced apoptosis40 and pathogenesis of MCL,42 and ERK activation has been described as a possible compensatory mechanism in Akt-compromised cells,43 we assessed the phosphorylation status of ERK and JNK in Z-138 cells exposed to edelfosine. As shown in Figure 2a, the level of p-JNK was dramatically increased during edelfosine exposure, whereas the p-ERK level was not modified during the first 9 h of treatment, and then decreased following the induction of apoptosis. However, despite p-JNK and p-ERK levels could be efficiently inhibited by JNK inhibitor SP600125 and ERK inhibitor PD98059, respectively (Figure 2b, and data not shown), these latter inhibitors did not significantly modify the cytotoxicity of ATLs, as assessed by hypodiploidy or Annexin V analyses (Figures 2c and d).

Bottom Line: The antitumor lipids (ATLs) edelfosine and perifosine target rafts, and we found that ATLs exerted in vitro and in vivo antitumor activity against MCL cells by displacing Akt as well as key regulatory kinases p-PDK1 (phosphatidylinositol-dependent protein kinase 1), PI3K and mTOR (mammalian TOR) from lipid rafts.Microenvironmental stimuli, such as CD40 ligation or stromal cell contact, did not prevent ATL-induced apoptosis in MCL cell lines and patient-derived cells.These results highlight the role of raft-mediated PI3K/Akt signaling in MCL cell survival and chemotherapy, thus becoming a new target for MCL treatment.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología Molecular y Celular del Cáncer, Centro de Investigación del Cáncer, CSIC-Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.

ABSTRACT
Recent evidence shows that lipid raft membrane domains modulate both cell survival and death. Here, we have found that the phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway is present in the lipid rafts of mantle cell lymphoma (MCL) cells, and this location seems to be critical for full activation and MCL cell survival. The antitumor lipids (ATLs) edelfosine and perifosine target rafts, and we found that ATLs exerted in vitro and in vivo antitumor activity against MCL cells by displacing Akt as well as key regulatory kinases p-PDK1 (phosphatidylinositol-dependent protein kinase 1), PI3K and mTOR (mammalian TOR) from lipid rafts. This raft reorganization led to Akt dephosphorylation, while proapoptotic Fas/CD95 death receptor was recruited into rafts. Raft integrity was critical for Ser473 Akt phosphorylation. ATL-induced apoptosis appeared to correlate with the basal Akt phosphorylation status in MCL cell lines and primary cultures, and could be potentiated by the PI3K inhibitor wortmannin, or inhibited by the Akt activator pervanadate. Classical Akt inhibitors induced apoptosis in MCL cells. Microenvironmental stimuli, such as CD40 ligation or stromal cell contact, did not prevent ATL-induced apoptosis in MCL cell lines and patient-derived cells. These results highlight the role of raft-mediated PI3K/Akt signaling in MCL cell survival and chemotherapy, thus becoming a new target for MCL treatment.

No MeSH data available.


Related in: MedlinePlus