Zurück

ID: 272 (Conflict of Interest: K)

Der Einfluss von Autophagie und epigenetischer Modulierung bei Nebennierenrindenkarzinomen

F.Goretic1, I.Mintziras1, S.Wächter2, D. K.Bartsch2, K.Holzer2, P.Di Fazio2
1Universitätsklinikum Marburg, Marburg
2Universitätsklinikum Marburg , Marburg

Einleitung

Current treatment options of adrenocortical carcinomas (ACC) are limited and result in poor prognosis and very high mortality. Patients` outcome is depending essentially on successful surgical resection.

In the last years, several studies have shown that in adrenocortical carcinoma the long non coding RNA H19 is down-regulated in favor of its counterpart transcript IGF2. This genetic profile correlates with high proliferation rate of ACC and its high metastatic potential. Autophagy modulation mediated by epigenetic modification represents a challenge to modify the vulnerability of cancer cells towards chemotherapeutics.

Our aim is to detect the expression of H19 in ACC probes from patients underwent surgical operation at Marburg Hospital and correlate its expression with autophagy markers. Furthermore, to explore if epigenetic modifications induced by histone deacetylase inhibitors in H295R adrenocortical cancer cells may lead to a change of the expression pattern of H19 and autophagy related genes.

Material und Methoden

Snap frozen tumor samples resected from 14 patients affected by ACC and operated at Marburg University Hospital between 2000 and 2017 were processed for RNA isolation. Corresponding normal tissue resected from patients was used as control. RT-qPCR was performed to detect the expression of H19 and autophagy markers. Cell viability of H295R mono-layer was analyzed by xCelligence. H295R spheroids morphology was monitored by phase contrast/fluorescence microscopy.

Ergebnisse

13 patient samples showed a significant down-regulation of H19 and 1 patient a stable expression. Interestingly the down-regulation of TFEB (transcription Factor EB), a master control of autophagy and lysosomal gene expression, was the most correlating autophagy marker (12 of 14 patients) towards expression of H19. Beclin1 (BECN1), UVRAG (UV Radiation Resistance Associated Gene), MAP1LC3B (Microtubule Associated Protein 1 Light Chain 3 Beta), SQSTM1 (p62) and PRKAA1_1, one of the two transcripts of AMPK-alpha (cAMP Kinase alpha) were down-regulated in the majority of the analyzed patients. The pan-deacetylase inhibitors Panobinostat, SAHA and TSA showed a significant reduction of H295R cell viability at nanomolar concentrations. The treatment of spheroids caused strong morphological changes, reduction of their volume and a complete dismantling of the spheroid outer membrane.

Schlussfolgerung

Almost all patients affected by ACC were characterized by a significant down-regulation of H19. Interestingly, the suppression of the long non coding RNA H19 correlates with the suppression of the above mentioned autophagy markers. Treatment with pan-deacetylase inhibitors caused a reduction of cell viability and morphological changes of H295R spheroids at nanomolar concentrations. Results represent new perspectives for the treatment of ACC in terms of higher efficacy and reduced dosage as shown for other cancer entities.