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
2728 - MicroRNA expression and DNA methylation profiles do not distinguish between primary and recurrent well-differentiated liposarcoma
Presenter: Melissa Vos
Session: Poster Display session 1
Resources:
Abstract
3197 - Genomic Alterations, Tumor Mutation Burden and Prognosis of Chinese Cardiac Sarcoma Patients
Presenter: Na Zhu
Session: Poster Display session 1
Resources:
Abstract
4214 - Evaluation of a peptide-conjugated alkylator melflufen in osteosarcoma preclinical models
Presenter: Konstantin Byrgazov
Session: Poster Display session 1
Resources:
Abstract
2654 - Expression analysis of NHEJ and HR genes in Ewing sarcomas: indications of DSB repair dysfunction
Presenter: Anastasios Kyriazoglou
Session: Poster Display session 1
Resources:
Abstract
4383 - Epidemiology of Synovial Sarcoma in EU28 countries
Presenter: Nedra Joseph
Session: Poster Display session 1
Resources:
Abstract
1937 - Resection Of High-Grade Large Soft Tissue Sarcoma With Adequate Wide Margin Can Lead To Good Local Control Without Adjuvant Radiotherapy
Presenter: Toshiyuki Kunisada
Session: Poster Display session 1
Resources:
Abstract
3757 - Influence of eribulin on proliferation, migration and invasion properties of leiomyosarcoma cell line models
Presenter: Marta Mendiola
Session: Poster Display session 1
Resources:
Abstract
1040 - EREMISS: Efficacy of regorafenib (REG) as maintenance therapy in non-adipocytic soft tissue sarcomas (STS) having received 1st-line doxorubicin-based chemotherapy (Doxo-CT)
Presenter: Nicolas Penel
Session: Poster Display session 1
Resources:
Abstract
1048 - A Phase 2 biomarker-driven study evaluating the clinical efficacy of an MDM2 inhibitor, milademetan, in patients with intimal sarcoma, a disease with a high unmet need
Presenter: Kan Yonemori
Session: Poster Display session 1
Resources:
Abstract
1511 - A pilot study of oral paclitaxel (ORAXOL) in subjects with cutaneous angiosarcomas (KX-ORAX-010)
Presenter: Herbert Loong
Session: Poster Display session 1
Resources:
Abstract