339P - Hypoxia, Inflammation and redox status as determinants of malignant progression of cancer stem cells

Date 10 September 2017
Event ESMO 2017 Congress
Session Poster display session
Topics Central Nervous System Malignancies
Translational Research
Presenter Marco Papale
Citation Annals of Oncology (2017) 28 (suppl_5): v109-v121. 10.1093/annonc/mdx366
Authors M. Papale
  • Medicina Sperimentale, Sapienza – Università di Roma, 185 - Roma/IT

Abstract

Background

Transformed cells live in a hostile environment characterized by lack of oxygen. Hypoxia produces: necrosis with alarmins release; activation of HIF1a. Recent studies have shown that HIF1a controls also the expression of membrane receptors in tumor cells. These receptors are part of the inflammatory reparative response (IRR) and have the capacity to bind and be activated by alarmins. Once activated, their signaling cascades lead to NFkB. Human tumor tissues posses 1-2% of cancer stem cells (CSCs) responsible for the metastatic potential of tumors. In particular, we investigated the overall hypothesis that, in CSCs from a primary tumor, hypoxia links the expression of IRR genes to tumor progression.

Methods

Hypoxia was achieved in a hypoxic chamber, where a 1% oxygen mix was flushed in for 4 min. Hypoxic response as well as efficacy of drugs treatments on CSCs was determined by measuring HIF1a, VEGF and other markers by WB and Immunofluorescence. Inflammation-like status was reproduced by treatment with necrotic extracts. Redox status was determined by the DCFH-DA. Expression of IRR and adhesion genes was determined by RT-PCR.

Results

Initially, two cell lines of Glioblastoma CSCs from two different tumors were selected and the protein and gene expression were analyzed by WB and RT-PCR. WB analysis showed that hypoxia promotes the expression of HIF1a and change the expression of other proteins directly related to HIF1a. Moreover the gene expression by RT-PCR showed many differences among the analyzed markers. Then we used multiple concentrations of digoxin and acriflavine in the two selected cell lines and also necrotic extracts. Both the drugs promote the reduction of the expression of HIF1a and other related markers. Moreover we used the drugs and an invasion assay kit for evaluation of invasive tumor cells. Also in this case, we observed modification in the invasiveness of CSCs.

Conclusions

Hypoxia promotes cells adaptation trough the expression of HIF1a, without new genetic mutations, and modify other HIF-target proteins such as VEGF, HKII, Rage. Using different concentrations of digoxin and acriflavine it is possible to modify protein and gene expression of HIF1a and related markers, modifing the production of ROS and the invasiveness of CSCs.

Clinical trial identification

Legal entity responsible for the study

Casa di cura San Raffaele Pisana - Rome

Funding

Ministero della salute

Disclosure

All authors have declared no conflicts of interest.