1. Academic Validation
  2. PDK1-mTOR signaling pathway inhibitors reduce cell proliferation in MK2206 resistant neuroblastoma cells

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

  • Cancer Cell Int. 2015 Sep 29;15:91. doi: 10.1186/s12935-015-0239-4.
Lei Qi 1 Hidemi Toyoda 2 Dong-Qing Xu 1 Ye Zhou 3 Naoto Sakurai 2 Keishirou Amano 2 Kentaro Kihira 2 Hiroki Hori 2 Eiichi Azuma 2 Yoshihiro Komada 2
Affiliations

Affiliations

  • 1 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.
  • 2 Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan.
  • 3 Department of Child Health Nursing, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan.
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.

Keywords

Akt; Cell growth; MK2206; Neuroblastoma; PDK1; mTOR.

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Products
  • Cat. No.
    Product Name
    Description
    Target
    Research Area
  • HY-14981
    99.78%, PDK1 Inhibitor