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
3909 - Spectrum of pathogenic germline mutations in Chinese lung cancer patients through next-generation sequencing
Presenter: Ying Huang
Session: Poster Display session 1
Resources:
Abstract
3061 - Poor prognostic impact of NTRK2 gene variation in Esophageal Squamous Cell Carcinoma
Presenter: Ye Chen
Session: Poster Display session 1
Resources:
Abstract
4735 - Mutation profile of Tibetan lung cancer revealed by Whole Exome Sequencing
Presenter: Xin Wang
Session: Poster Display session 1
Resources:
Abstract
5236 - Synergistic activity between niraparib and chemotherapy in colorectal cancer: molecular determinants from a preclinical model
Presenter: Pietro Paolo Vitiello
Session: Poster Display session 1
Resources:
Abstract
4051 - cRGDfK (cRGD) conjugated Pyropheophor¬bide-a (Pyro), a new tumor photodynamic agent, is highly accumulated and specific in tumor cell killing
Presenter: Fengwei Wang
Session: Poster Display session 1
Resources:
Abstract
859 - The expression of MMR, CD133 and the presence of p53 wt predict the response to Cabazitaxel in malignant neural tumors cell lines.
Presenter: Kevin Doello
Session: Poster Display session 1
Resources:
Abstract
2497 - IKS01, a next generation antibody drug conjugate (ADC) designed to be efficacious in tumors with low and moderate levels of folate receptor expression
Presenter: Jenny Thirlway
Session: Poster Display session 1
Resources:
Abstract
1636 - Novel Non-Camptothecin Compounds with Antiproliferative Activities against Breast Cancer Cells
Presenter: Wen-shan Li
Session: Poster Display session 1
Resources:
Abstract
3443 - Sensitization of estrogen receptor-positive breast cancer cells to tamoxifen by novel epi-oligomycin A
Presenter: Margarita Yastrebova
Session: Poster Display session 1
Resources:
Abstract
840 - Autophagy inhibition enhances leflunomide-induced cytotoxicity in human bladder cancer cells
Presenter: Li Cheng
Session: Poster Display session 1
Resources:
Abstract