Myxoma virus-mediated oncolysis of ascites-derived human ovarian cancer cells and spheroids is impacted by differential AKT activity

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• 作者：Rohann J.M. Correa^a ; ^b ; Monica Komar^a ; Jessica G.K. Tong^c ; Milani Sivapragasam^a ; Masmudur M. Rahman^f ; Grant McFadden^f ; Gabriel E. DiMattia^a ; ^b ; ^d ; ^e ; Trevor G. Shepherd^a ; ^c ; ^d ; ^e ; ^{tshephe6@uwo.ca}
• 关键词：Ovarian cancer ; Ascites ; Spheroid ; Oncolytic virus ; Myxoma virus ; AKT kinase
• 刊名：Gynecologic Oncology
• 出版年：2012
• 期刊代码：295_00908258
• 类别：med
• 出版时间：May, 2012
• 卷：125
• 期：2
• 页码：441-450
• 文件大小：1616 K

摘要

Objective

We propose that metastatic epithelial ovarian cancer (EOC) is a potential therapeutic target for the oncolytic agent, Myxoma virus (MYXV).

Methods

Primary EOC cells were isolated from patient ascites and cultured as adherent cells or in suspension using Ultra Low-Attachment dishes. MYXV expressing green fluorescent protein was used to infect cells and spheroids. Infection was monitored by fluorescence microscopy, viral titering and immunoblotting for M-T7 and M130 virus protein expression, and cell viability by alamarBlue assay. Akti-1/2 (5 渭M) and rapamycin (20 nM) were used to assay the role of PI3K-AKT signaling in mediating MYXV infection.

Results

Ascites-derived EOC cells grown in adherent culture are effectively killed by MYXV infection. EOC cells grown in suspension to form three-dimensional EOC spheroids readily permit MYXV entry into cells, yet are protected from the cytopathic effects of late MYXV infection. Upon reattachment (to model secondary metastasis), EOC spheroids are re-sensitized to MYXV-mediated oncolysis. The critical determinant that facilitates efficient MYXV infection is the presence of an activated PI3K-AKT signaling pathway. Treatment with the specific AKT inhibitor Akti-1/2 reduces infection of monolayer EOC cells and spheroids. Direct infection of freshly-collected ascites demonstrated that 54.5%of patient samples were sensitive to MYXV-mediated oncolytic cell killing. We also demonstrate that factor(s) present in ascites may negatively impact MYXV infection and oncolysis of EOC cells, which may be due to a down-regulation in endogenous AKT activity.

Conclusions

Differential activity of AKT serves as the mechanistic basis for regulating MYXV-mediated oncolysis of EOC spheroids during key steps of the metastatic program. In addition, we provide the first evidence that MYXV oncolytic therapy may be efficacious for a significant proportion of ovarian cancer patients with metastatic disease.