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PDK1-mTOR signaling pathway inhibitors reduce cell proliferation in MK2206 resistant neuroblastoma cells.

Qi L, Toyoda H, Xu DQ, Zhou Y, Sakurai N, Amano K, Kihira K, Hori H, Azuma E, Komada Y - Cancer Cell Int. (2015)

Bottom Line: GSK2334470 and AZD8055 effectively inhibited phosphorylation of PDK1 and mTOR, respectively, and induced higher G0-G1 ratio in LAN-1-MK than that in LAN-1 as well.PDK1 and mTOR inhibitors effected on phosphorylation of GSK3β in some of resistant sublines.Thus, suppression of PDK1-mTOR-S6K signaling pathway is an effective way to overcome the MK2206 resistance, and this may be a promising strategy for targeted therapy.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan ; Department of Pediatrics, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, 200092 China.

ABSTRACT

Purpose: AKT plays a pivotal role in the signal transduction of cancer cells. MK2206, an AKT inhibitor, has been shown to be an effective anti-cancer drug to a variety of cancer cell lines. However, some cancer cells acquire resistance to MK2206 and new strategies to suppress these cell lines remain to be developed.

Experimental design: Acquired MK-2206-resistant neuroblastoma (NB) cell sublines were induced by stepwise escalation of MK-2206 exposure (4-12 weeks). MTT assay was used to validate cell proliferation. Flow cytometry was performed for cell cycle analysis. Western blot assay was used for cell signaling study.

Results: MK2206 (5-10 µmol) significantly suppressed cell growth of MK2206 non-resistant NB cells (LAN-1, KP-N-SIFA, NB-19 and SK-N-DZ), but is less efficient in inhibiting that of resistant sublines, even after 2-week MK2206-free incubation. MK2206 acted in mTOR-S6K dependent and independent methods. MK-2206 resistant sublines (LAN-1-MK, KP-N-SIFA-MK, and SK-N-DZ-MK) showed lower IC50 of GSK2334470 (PDK1 inhibitor). The cell growth of all sublines was prohibited by AZD8805 (mTOR inhibitor), with IC50 of AZD8805 3-10 times lower than MK2206 non-resistant cells. The signaling profiles of these resistant sublines were characterized by elevated PDK1-mTOR-S6K activity, accompanying by low phosphorylation of AKT compared with non-resistant counterparts. GSK2334470 and AZD8055 effectively inhibited phosphorylation of PDK1 and mTOR, respectively, and induced higher G0-G1 ratio in LAN-1-MK than that in LAN-1 as well. PDK1 and mTOR inhibitors effected on phosphorylation of GSK3β in some of resistant sublines.

Conclusion: NB cells can acquire MK2206 resistance after exposure for 4-12 weeks. Resistant cells feature reliance on PDK1-mTOR-S6K pathway and are more sensitive to PDK1 and mTOR inhibitors than the non-resistant counterparts. Thus, suppression of PDK1-mTOR-S6K signaling pathway is an effective way to overcome the MK2206 resistance, and this may be a promising strategy for targeted therapy.

No MeSH data available.


Related in: MedlinePlus

MK-2206 suppressed the cell growth of NB cells. a MK-2206 suppressed the cell growth of NB cell lines. LAN-1, KP-N-SIFA, NB-19, and SK-N-DZ cells were cultured in RPMI1640 + 10 % FBS with MK-2206 at indicated concentrations. Cell growth was evaluated as cell numbers at 72 h, and it was repeated three times. Data are expressed as the mean (±SD). b Photomicrographs of MK-2206 non-resistant and resistant cells. Cells were cultured in glass bottom slide chambers with RPMI1640 + 10 % FBS, with MK-2206 (resistant sublines)/without MK-2206 (non-resistant cells) overnight. A 50 µm scale is indicated (Olympus Fluoview fv1000, DIC acquisition, ×40)
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Fig1: MK-2206 suppressed the cell growth of NB cells. a MK-2206 suppressed the cell growth of NB cell lines. LAN-1, KP-N-SIFA, NB-19, and SK-N-DZ cells were cultured in RPMI1640 + 10 % FBS with MK-2206 at indicated concentrations. Cell growth was evaluated as cell numbers at 72 h, and it was repeated three times. Data are expressed as the mean (±SD). b Photomicrographs of MK-2206 non-resistant and resistant cells. Cells were cultured in glass bottom slide chambers with RPMI1640 + 10 % FBS, with MK-2206 (resistant sublines)/without MK-2206 (non-resistant cells) overnight. A 50 µm scale is indicated (Olympus Fluoview fv1000, DIC acquisition, ×40)

Mentions: To study the inhibitory effect of MK-2206 on NB cell growth, cells (LAN-1, NB-19, KP-N-SIFA, and SK-N-DZ) were selected and treated with MK-2206 at indicated concentrations for 72 h. MK-2206 treatment induced a dose dependent inhibition of cell proliferation, with IC50 ranging from 1.22 μM (KP-N-SIFA) to 4.35 μM (NB-19) (Figs. 1a and 2b). These cells were deined as MK-2206 non-resistant cells.Fig. 1


PDK1-mTOR signaling pathway inhibitors reduce cell proliferation in MK2206 resistant neuroblastoma cells.

Qi L, Toyoda H, Xu DQ, Zhou Y, Sakurai N, Amano K, Kihira K, Hori H, Azuma E, Komada Y - Cancer Cell Int. (2015)

MK-2206 suppressed the cell growth of NB cells. a MK-2206 suppressed the cell growth of NB cell lines. LAN-1, KP-N-SIFA, NB-19, and SK-N-DZ cells were cultured in RPMI1640 + 10 % FBS with MK-2206 at indicated concentrations. Cell growth was evaluated as cell numbers at 72 h, and it was repeated three times. Data are expressed as the mean (±SD). b Photomicrographs of MK-2206 non-resistant and resistant cells. Cells were cultured in glass bottom slide chambers with RPMI1640 + 10 % FBS, with MK-2206 (resistant sublines)/without MK-2206 (non-resistant cells) overnight. A 50 µm scale is indicated (Olympus Fluoview fv1000, DIC acquisition, ×40)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4587771&req=5

Fig1: MK-2206 suppressed the cell growth of NB cells. a MK-2206 suppressed the cell growth of NB cell lines. LAN-1, KP-N-SIFA, NB-19, and SK-N-DZ cells were cultured in RPMI1640 + 10 % FBS with MK-2206 at indicated concentrations. Cell growth was evaluated as cell numbers at 72 h, and it was repeated three times. Data are expressed as the mean (±SD). b Photomicrographs of MK-2206 non-resistant and resistant cells. Cells were cultured in glass bottom slide chambers with RPMI1640 + 10 % FBS, with MK-2206 (resistant sublines)/without MK-2206 (non-resistant cells) overnight. A 50 µm scale is indicated (Olympus Fluoview fv1000, DIC acquisition, ×40)
Mentions: To study the inhibitory effect of MK-2206 on NB cell growth, cells (LAN-1, NB-19, KP-N-SIFA, and SK-N-DZ) were selected and treated with MK-2206 at indicated concentrations for 72 h. MK-2206 treatment induced a dose dependent inhibition of cell proliferation, with IC50 ranging from 1.22 μM (KP-N-SIFA) to 4.35 μM (NB-19) (Figs. 1a and 2b). These cells were deined as MK-2206 non-resistant cells.Fig. 1

Bottom Line: GSK2334470 and AZD8055 effectively inhibited phosphorylation of PDK1 and mTOR, respectively, and induced higher G0-G1 ratio in LAN-1-MK than that in LAN-1 as well.PDK1 and mTOR inhibitors effected on phosphorylation of GSK3β in some of resistant sublines.Thus, suppression of PDK1-mTOR-S6K signaling pathway is an effective way to overcome the MK2206 resistance, and this may be a promising strategy for targeted therapy.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan ; Department of Pediatrics, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, 200092 China.

ABSTRACT

Purpose: AKT plays a pivotal role in the signal transduction of cancer cells. MK2206, an AKT inhibitor, has been shown to be an effective anti-cancer drug to a variety of cancer cell lines. However, some cancer cells acquire resistance to MK2206 and new strategies to suppress these cell lines remain to be developed.

Experimental design: Acquired MK-2206-resistant neuroblastoma (NB) cell sublines were induced by stepwise escalation of MK-2206 exposure (4-12 weeks). MTT assay was used to validate cell proliferation. Flow cytometry was performed for cell cycle analysis. Western blot assay was used for cell signaling study.

Results: MK2206 (5-10 µmol) significantly suppressed cell growth of MK2206 non-resistant NB cells (LAN-1, KP-N-SIFA, NB-19 and SK-N-DZ), but is less efficient in inhibiting that of resistant sublines, even after 2-week MK2206-free incubation. MK2206 acted in mTOR-S6K dependent and independent methods. MK-2206 resistant sublines (LAN-1-MK, KP-N-SIFA-MK, and SK-N-DZ-MK) showed lower IC50 of GSK2334470 (PDK1 inhibitor). The cell growth of all sublines was prohibited by AZD8805 (mTOR inhibitor), with IC50 of AZD8805 3-10 times lower than MK2206 non-resistant cells. The signaling profiles of these resistant sublines were characterized by elevated PDK1-mTOR-S6K activity, accompanying by low phosphorylation of AKT compared with non-resistant counterparts. GSK2334470 and AZD8055 effectively inhibited phosphorylation of PDK1 and mTOR, respectively, and induced higher G0-G1 ratio in LAN-1-MK than that in LAN-1 as well. PDK1 and mTOR inhibitors effected on phosphorylation of GSK3β in some of resistant sublines.

Conclusion: NB cells can acquire MK2206 resistance after exposure for 4-12 weeks. Resistant cells feature reliance on PDK1-mTOR-S6K pathway and are more sensitive to PDK1 and mTOR inhibitors than the non-resistant counterparts. Thus, suppression of PDK1-mTOR-S6K signaling pathway is an effective way to overcome the MK2206 resistance, and this may be a promising strategy for targeted therapy.

No MeSH data available.


Related in: MedlinePlus