Oncotarget

Research Papers:

The PI3K/AKT/mTOR pathway is a potential predictor of distinct invasive and migratory capacities in human ovarian cancer cell lines

Huimin Bai, Haixia Li, Weihua Li, Ting Gui, Jiaxin Yang, Dongyan Cao _ and Keng Shen

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Oncotarget. 2015; 6:25520-25532. https://doi.org/10.18632/oncotarget.4550

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Abstract

Huimin Bai1,2,*, Haixia Li1,*, Weihua Li1, Ting Gui1, Jiaxin Yang1, Dongyan Cao1, Keng Shen1

1Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing China

2Department of Obstetrics and Gynecology, Beijing Chao-Yang Hospital, China Capital Medical University, Beijing China

*These authors have contributed equally to this work

Correspondence to:

Dongyan Cao, e-mail: [email protected]

Keng Shen, e-mail: [email protected], [email protected]

Keywords: ovarian cancer, intratumoral heterogeneity, cell subclones, invasion and migration, RNA-Seq

Received: March 30, 2015     Accepted: July 04, 2015     Published: July 14, 2015

ABSTRACT

Objectives: To explore the genetic and molecular events that control subclones exhibiting distinct invasive/migratory capacities derived from human epithelial ovarian cancer (EOC) cell line A2780 and SKOV3.

Methods: Single-cell subclones were isolated and established that were derived from the SKOV3 and A2780 cell lines through limiting dilution methodology. Transwell insert assays and MTT assays were performed to screen and identify the subclones exhibiting the highest and the lowest invasive/migratory capacities, and the selected subclones were renamed as A-H (A2780 high), A-L (A2780 low), S-H (SKOV3 high), and S-L (SKOV3 low). Their biological characteristics were evaluated. RNA-Seq was conducted on the targeted subclones.

Results: Compared with their corresponding counterparts, A-H/S-H cells exhibited significantly higher invasive/migratory capacities (P < 0.001 and = 0.001, respectively). A-H/S-H cells displayed a clear reduction in doubling time (P = 0.004 and 0.001, respectively), and a significant increase in the percentage of cells in S phase (P = 0.004 and 0.022, respectively). Additionally, the apoptotic rates of A-H/S-H cells were significantly lower than those of A-L/S-L cells (P = 0.002 and 0.026, respectively). At both mRNA and protein levels, caspase-3 and caspase-7 expression were reduced but Bcl-2 expression was increased in A-H/S-H cells. The TrkB (anoikis-related) and Beclin1 (autophagy-related) levels were consistently high and low, respectively, in both A-H/S-H cells. Resistance to chemotherapy in vitro and higher capacities on tumor formation in vivo was presented in both A-H/S-H cells. PI3K/AKT/mTOR pathway components, PIK3CA, PIK3CD, AKT3, ECM1, GPCR, mTOR and PRKCB were increased but that the Nur77 and PTEN were decreased in A-H/S-H cells, identified by RNA-Seq and consistently confirmed by RT-PCR and Western blot analyses.

Conclusions: Heterogeneous cell subpopulations exhibiting distinct invasive and migratory capacities co-exist within the SKOV3 and A2780 cell lines. PI3K/AKT/mTOR pathway activation is associated with higher invasive and migratory capacities in subpopulations of human ovarian cancer cell lines. Inhibiting this pathway may be useful for the chemoprevention or treatment of EOC.


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