Induction of Divergent Cell Death Pathways by Urea and Carbohydrazide Derivatives
Sinem Yilmaz1,2, Fatih Tok3, Esra Atalay-Sahar1
1Department of Biotechnology, Graduate School of Natural and Applied Sciences, Ege University, Izmir, Turkey.
Background:
The complexity of cancer biology and the development of chemotherapy resistance are two main obstacles to cancer treatment and necessitate novel anticancer molecules that target different cell death pathways. Modulation of Endoplasmic Reticulum (ER) stress and subsequent activation of the Unfolded Protein Response (UPR) has been proposed as a potential chemotherapeutic target, as prolonged ER stress can lead to cell death via apoptosis or necrosis.
Objective:
The present study aims to evaluate the molecular mechanism underlying the cytotoxic activity of selected urea and carbohydrazide derivatives.
Methods:
Cell proliferation assays were performed on HeLa, Capan-1, MCF-7, HCC-1937, and MRC-5 cell lines by WST-1 assay. The expression levels of selected ER stress, autophagy, and apoptosis marker proteins were compared by immunoblotting to characterize the underlying mechanism of cytotoxicity. Flow cytometry was used to detect apoptosis.
Results:
Of the tested cytotoxic compounds, 3a, 4a, 5a, 6a, and 1b dramatically and 5b moderately increased ER stress-related CHOP protein levels. Interestingly, 5b but not 3a, 4a, 5a, 6a, or 1b increased the expression of proapoptotic proteins such as cleaved PARP-1 and cleaved caspase-3 and -7. The flow-cytometry analysis further confirmed that the cytotoxic activity of 5b but not the other compounds is mediated by apoptosis, demonstrated by a significant increase in the percentage of late apoptotic cells (7-AAD/annexin V double-positive cells).
Conclusion:
Our results suggest that changing a substituent from trifluoromethyl to nitro in urea and carbohydrazide core structure alters the cell death mechanism from apoptosis to an apoptosis-independent cell death pathway. This study shows an example of how such simple modifications of a core chemical structure could cause the induction of divergent cell death pathways.
Insights
Simple chemical modifications can alter cancer cell death pathways. This study reveals how changing substituents in urea and carbohydrazide derivatives shifts cell death from apoptosis to other mechanisms, offering new anticancer strategies.
Area of Science:
- Biochemistry
- Molecular Biology
- Medicinal Chemistry
Background:
- Cancer treatment faces challenges from complex biology and chemotherapy resistance.
- Targeting Endoplasmic Reticulum (ER) stress and the Unfolded Protein Response (UPR) presents a novel therapeutic strategy.
- ER stress can induce cancer cell death through apoptosis or necrosis.
Purpose of the Study:
- To investigate the molecular mechanisms behind the cytotoxic effects of specific urea and carbohydrazide derivatives.
- To understand how structural modifications influence cancer cell death pathways.
Main Methods:
- Cell proliferation was assessed using WST-1 assays across multiple cancer cell lines (HeLa, Capan-1, MCF-7, HCC-1937) and a normal cell line (MRC-5).
- Protein expression of ER stress, autophagy, and apoptosis markers was analyzed via immunoblotting.
- Apoptosis was quantified using flow cytometry (7-AAD/annexin V staining).
Main Results:
- Compounds 3a, 4a, 5a, 6a, and 1b significantly elevated ER stress marker CHOP.
- Compound 5b uniquely increased proapoptotic proteins (cleaved PARP-1, cleaved caspase-3, -7) and induced apoptosis, confirmed by flow cytometry.
- Other tested compounds did not induce apoptosis, suggesting alternative cell death mechanisms.
Conclusions:
- Modifying substituents on urea and carbohydrazide cores can switch the cell death pathway from apoptosis to apoptosis-independent mechanisms.
- Simple structural alterations can lead to divergent cell death pathway induction, highlighting potential for novel anticancer drug design.
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