Abstract 1659
Background
In HT29 cells, an interplay between self-DNA-induced TLR9-signaling and autophagy response was found with significant effects on cell survival and kinetic parameters. The IGF/IGF1R system plays a determinant role in the pathogenesis and progression of colorectal cancer. This pathway is upstream of mTORC1, a negative regulator of autophagy. I mammalian systems chronic IGF1R inhibition was shown to attenuate autophagosome formation. The interrelated action of IGF1R inhibition and TLR9/autophagy signaling in cancer cells has not yet been clarified. The present study was designed to assess this complex network using HT29 colon carcinoma cells.
Methods
HT29 cells were incubated for 72 h with genomic (g), hypermethylated (m), and fragmented (f) tumor self-DNAs, and with/without inhibitors of IGF1R (picropodophyllin), autophagy (chloroquine) and TLR9 (ODN2088), respectively. Cell viability was measured by MTT assay. Transcriptional changes of TLR9-signaling, IGF1R, mTORC, Akt, 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
In case of autophagy g- and f-DNAs caused significant upregulation of Beclin1, Atg16L1, LC3 mRNAs, and downregulation of mTORC, and Akt, verified by immunocytochemistry, as well. IGF1R-inhibition alone altered inversely the autophagy-associated gene- and protein-expressions. Upon combined inhibition of autophagy, TLR9 and/or IGF1R-signaling varying degree of autophagy was detected in all groups of tumor cells according to NanoString and TEM. Incubation with IGF1R inhibitor and with m-DNA no expected suppression of tumor cell survival, induction of apoptotic death, and activation of mitophagy were found. Moreover, IGF1R inhibition affected negatively the cell-protective effect f-DNA on macroautophagy and lipophagy.
Conclusions
Our study provided evidence for an interaction between the inhibited IGF1R and TLR9/autophagy signaling with major influences on survival, proliferation and death of HT29 cells subjected to intact/modified self-DNAs. (Funded by StartUp.).
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
1271 - A large scale prospective concordance study of oncogene driver detection between plasma- and tissue-based NGS analysis in advanced non-small cell lung cancer (NSCLC).
Presenter: Ryo Itotani
Session: Poster Display session 1
Resources:
Abstract
1132 - Biomarker status as a mediator of age-related overall survival (OS) in advanced non-small cell lung cancer (aNSCLC)
Presenter: Aaron Cohen
Session: Poster Display session 1
Resources:
Abstract
1502 - An exploratory analysis of on-treatment ctDNA measurement as a potential surrogate for overall survival for atezolizumab benefit in the OAK Study
Presenter: David Gandara
Session: Poster Display session 1
Resources:
Abstract
3912 - Disease monitoring of EGFR mutation-positive NSCLC patients via circulating tumor DNA
Presenter: Wei Fang Hsu
Session: Poster Display session 1
Resources:
Abstract
3856 - Incidence of T790M in NSCLC patients progressed to gefitinib, erlotinib, and afatinib: a study on circulating tumor DNA
Presenter: Romano Danesi
Session: Poster Display session 1
Resources:
Abstract
1330 - Folate receptor-positive circulating tumor cells as a predictive biomarker for the efficacy of first-line pemetrexed-based therapy in patients with non-squamous non-small cell lung cancer
Presenter: Xiaoxia Chen
Session: Poster Display session 1
Resources:
Abstract
3512 - Carcinoembryonic Antigen of Cerebrospinal Fluid Predict Prognosis of Leptomeningeal Metastasis from Non-Small Cell Lung Cancer
Presenter: Junjie Zhen
Session: Poster Display session 1
Resources:
Abstract
3852 - Liquid biopsy in clinical pratice of Non-Small-Cell-Lung Cancer (NSCLC): a multi-institutional experience
Presenter: Giovanna De Maglio
Session: Poster Display session 1
Resources:
Abstract
1205 - A Phase III Study Comparing SB8, a Proposed Bevacizumab Biosimilar, and Reference Bevacizumab in Patients with Metastatic or Recurrent Non-squamous NSCLC
Presenter: Martin Reck
Session: Poster Display session 1
Resources:
Abstract
2432 - Retrospective comparative study of the efficacy and safety in docetaxel and ramucirumab combination chemotherapy with or without previous immune checkpoint inhibitor treatment.
Presenter: Daijiro Harada
Session: Poster Display session 1
Resources:
Abstract