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Phospho-Akt overexpression is prognostic and can be used to tailor the synergistic interaction of Akt inhibitors with gemcitabine in pancreatic cancer.
- Source :
-
Journal of hematology & oncology [J Hematol Oncol] 2017 Jan 06; Vol. 10 (1), pp. 9. Date of Electronic Publication: 2017 Jan 06. - Publication Year :
- 2017
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Abstract
- Background: There is increasing evidence of a constitutive activation of Akt in pancreatic ductal adenocarcinoma (PDAC), associated with poor prognosis and chemoresistance. Therefore, we evaluated the expression of phospho-Akt in PDAC tissues and cells, and investigated molecular mechanisms influencing the therapeutic potential of Akt inhibition in combination with gemcitabine.<br />Methods: Phospho-Akt expression was evaluated by immunohistochemistry in tissue microarrays (TMAs) with specimens tissue from radically-resected patients (nā=ā100). Data were analyzed by Fisher and log-rank test. In vitro studies were performed in 14 PDAC cells, including seven primary cultures, characterized for their Akt1 mRNA and phospho-Akt/Akt levels by quantitative-RT-PCR and immunocytochemistry. Growth inhibitory effects of Akt inhibitors and gemcitabine were evaluated by SRB assay, whereas modulation of Akt and phospho-Akt was investigated by Western blotting and ELISA. Cell cycle perturbation, apoptosis-induction, and anti-migratory behaviors were studied by flow cytometry, AnnexinV, membrane potential, and migration assay, while pharmacological interaction with gemcitabine was determined with combination index (CI) method.<br />Results: Immunohistochemistry of TMAs revealed a correlation between phospho-Akt expression and worse outcome, particularly in patients with the highest phospho-Akt levels, who had significantly shorter overall and progression-free-survival. Similar expression levels were detected in LPC028 primary cells, while LPC006 were characterized by low phospho-Akt. Remarkably, Akt inhibitors reduced cancer cell growth in monolayers and spheroids and synergistically enhanced the antiproliferative activity of gemcitabine in LPC028, while this combination was antagonistic in LPC006 cells. The synergistic effect was paralleled by a reduced expression of ribonucleotide reductase, potentially facilitating gemcitabine cytotoxicity. Inhibition of Akt decreased cell migration and invasion, which was additionally reduced by the combination with gemcitabine. This combination significantly increased apoptosis, associated with induction of caspase-3/6/8/9, PARP and BAD, and inhibition of Bcl-2 and NF-kB in LPC028, but not in LPC006 cells. However, targeting the key glucose transporter Glut1 resulted in similar apoptosis induction in LPC006 cells.<br />Conclusions: These data support the analysis of phospho-Akt expression as both a prognostic and a predictive biomarker, for the rational development of new combination therapies targeting the Akt pathway in PDAC. Finally, inhibition of Glut1 might overcome resistance to these therapies and warrants further studies.
- Subjects :
- Aged
Apoptosis drug effects
Biopsy
Carcinoma, Pancreatic Ductal diagnosis
Carcinoma, Pancreatic Ductal pathology
Cell Cycle drug effects
Cell Movement drug effects
Deoxycytidine therapeutic use
Drug Synergism
Female
Glucose Transporter Type 1 drug effects
Humans
Male
Middle Aged
Pancreatic Neoplasms diagnosis
Pancreatic Neoplasms pathology
Phosphoproteins analysis
Phosphoproteins antagonists & inhibitors
Prognosis
RNA, Messenger analysis
Spheroids, Cellular
Tumor Cells, Cultured
Gemcitabine
Carcinoma, Pancreatic Ductal drug therapy
Deoxycytidine analogs & derivatives
Pancreatic Neoplasms drug therapy
Proto-Oncogene Proteins c-akt analysis
Proto-Oncogene Proteins c-akt antagonists & inhibitors
Subjects
Details
- Language :
- English
- ISSN :
- 1756-8722
- Volume :
- 10
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Journal of hematology & oncology
- Publication Type :
- Academic Journal
- Accession number :
- 28061880
- Full Text :
- https://doi.org/10.1186/s13045-016-0371-1