Abstract 1657
Background
In HT29 cells, an interplay between self-DNA-induced TLR9- and autophagy responses was found with remarkable effects on survival and differentiation of tumor cells. c-Met activation is known to drive the progression of colorectal cancer by promoting signaling cascades that mainly result in alterations of cell motility, survival and proliferation. c-Met inhibition was shown to inhibit autophagy. In cancer cells the interrelated role of c-Met inhibition and TLR9/autophagy signaling has not yet been clarified, so we aimed to assess this complex interplay.
Methods
HT29 cells were incubated for 72 h with genomic (g), hypermethylated (m), and fragmented (f) tumor self-DNAs, and with/without inhibitors of c-Met (diisothiocyanatostilbene), autophagy (chloroquine) and TLR9 (ODN2088), respectively. Cell viability was measured by MTT assay. Transcriptional changes of TLR9-signaling, PI3K, CD95, c-Met, Bcl2, cytochrome-c, and the autophagy process were assayed by Human v3 miRNA Assay (NanoString). Autophagy proteins were detected by immunocytochemistry, while morphology of apoptosis and autophagy by transmission electron microscopy (TEM).
Results
Self-DNAs g and f resulted in significant upregulation of Beclin1, Atg16L1, LC3 mRNAs, and downregulation of PI3K, Bcl2, CD95, and cytochrome-c, verified by immunocytochemistry, as well. c-Met inhibition alone altered inversely the autophagy-associated gene- and protein-expressions. In each group of tumor cells using combined inhibition of autophagy, TLR9 and/or c-Met-signaling varying degree of autophagy was observed according to NanoString and TEM. Following combined incubation with c-Met inhibitor and m-DNAs no expected suppression of tumor cell survival and induction of apoptosis and mitophagy were detected. Further, c-Met inhibition changed the cell-protective effect f-DNA on macroautophagy.
Conclusions
Our study provided evidence for an intense crosstalk between the inhibited c-Met canonical and non-canonical signaling pathways, and the TLR9/autophagy response with profound impacts on survival, proliferation and death of HT29 cells subjected to intact/modified self-DNAs.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Ferenc Sipos.
Funding
StartUp.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
3088 - Spanish Survey of treatment recommendations for elderley patients with glioblastoma
Presenter: María Ángeles Vaz Salgado
Session: Poster Display session 1
Resources:
Abstract
3484 - Updated analysis of the National Registry of Nervous System Tumors in Spain (RETSINE). RETSINE: National Registry of Nervous System Tumors of the Spanish Research Group in Neuro-oncology (GEINO) and Spanish Infrequent and Orphan Tumors Group (GETHI)
Presenter: Isaac Ceballos Lenza
Session: Poster Display session 1
Resources:
Abstract
4737 - Development and validation of novel nomograms predicting survival of malignant ependymoma patients: A population-based study
Presenter: Alzhraa Abbas
Session: Poster Display session 1
Resources:
Abstract
4740 - Characteristics, incidence, and survival of primary cerebral lymphoma: A population based study
Presenter: Sherief Ghozy
Session: Poster Display session 1
Resources:
Abstract
5362 - Trends in Incidence and Survival Analyses of Adult-onset Medulloblastoma
Presenter: Feifei Lin
Session: Poster Display session 1
Resources:
Abstract
3868 - Meta of classical chemotherapy compared with high-dose chemotherapy combined with autologous stem cell transplantation in newly diagnosed medulloblastoma patients after radiotherapy
Presenter: Mengting Zhang
Session: Poster Display session 1
Resources:
Abstract
4446 - Effect of cumulative dose of maintenance temozolomide on overall survival in patients with high grade glia tumors: a single institution analysis
Presenter: Marta Nerone
Session: Poster Display session 1
Resources:
Abstract
5119 - Markers of systemic inflammation correlate with survival prognosis in patients with newly diagnosed brain metastases
Presenter: Angelika Starzer
Session: Poster Display session 1
Resources:
Abstract
3882 - Venous Thromboembolism and Intracranial Hemorrhage in Patients with High-grade Glioma
Presenter: Clara Borges
Session: Poster Display session 1
Resources:
Abstract
5152 - Comprehensive Geriatric Assessment (CGA) can categorize elderly glioblastoma (GBM) patients into three groups predicting survival: a monoinstitutional study
Presenter: Eleonora Bergo
Session: Poster Display session 1
Resources:
Abstract