PhD Scientific Days 2024

Pharmaceutical Sciences and Health Technologies I.

ONC-201 and its Fluorinated Analogues: Characterization of Apoptotic Protein Expression of Gemcitabine-Resistant Pancreatic Cancer Cells

Text of the abstract

Introduction: Pancreatic ductal adenocarcinoma (PDAC) has a high mortality rate, the 5-year survival rate is ~12%. Resistance often develops during the treatment of gemcitabine monotherapy. For these reasons, the development of new targeted therapy is a matter of great urgency. One of the potential candidates is ONC-201, which is already being tested in clinical trials.
Aim: The main objective of the present work is to investigate the underlying molecular mechanism of the antitumour activity of ONC-201 and its two fluorinated analogues (TBP-134, TBP-135) and to determine their cardiotoxicity.
Methods: PANC-1 (PDAC cell line) – (i) protein expression study: Human Proteom Profiler Apoptosis Array kit and flow cytometer (Cytoflex), (ii) gene expression analysis: RT-qPCR (CFX96 Touch). HL-1 (mouse cardiomyocyte cell line) – characterisation of cardiotoxicity: CellTiter Glo.
Results: Four genes (DR4, DR5, p53, TRAIL) were analysed for RNA expression. TBP-134 significantly upregulated DR4 by 3.74-fold at 24 hours. DR5 was upregulated by ONC-201 and TBP-134 at 12 hours and by TBP-135 at 24 hours (5.90-fold). p53 expression increased aftter TBP-134 treatment (3.71-fold at 48 hours). TRAIL induction wasn't observed with ONC-201 or TBP-134, but TBP-135 showed a 2.36-fold increase. Treatment with the molecules at 0.5 μM for 72 hours induced changes in the expression profile of apoptotic proteins. ONC-201 increased pro-apoptotic proteins such as cleaved caspase-3, FADD, DR5, SMAC and phospho-p53, but also anti-apoptotic ones (e.g. XIAP). TBP-135 had the same effect as ONC-201, whereas a different protein profile was observed after treatment with TBP-134. Flow cytometry showed that ONC-201 and TBP-135 increased intracellular TRAIL levels similarly, while they influenced the cell surface level of the protein differently. In our cardiotoxicity study on HL-1 cells, no IC50 values could be calculated in the tested range (0.5-25 μM), in contrast to gemcitabine, which showed high cardiotoxicity (IC50 < 50 nM).
Conclusion: All three molecules exhibit a potent antitumour effect against PANC-1 cells without causing cardiotoxicity. They induce apoptosis primarily through the DR5 and DR4 pathways, with TBP-134 showing the highest efficacy. TBP-134 is a promising candidate for further studies to target pancreatic adenocarcinoma.
Funding: SE250+ fellowship, EFOP-3.6.3-VEKOP-16-2017-00009