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Efficacy of substituted 9-aminoacridine derivatives in small cell lung cancer
Etchison Ryan1, A Jacobson Blake, A Benoit
1Unviersity of Minnesota Medical School, Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, MN, USA.
Abstract:
Topoisomerase II (TopoII) plays a critical role in the processes of replication, transcription, and decantenation in the cell and is an important chemotherapeutic target in the treatment of small cell lung cancer (SCLC). Current treatment strategies for SCLC employ the use of topoII poisons which stabilize the topoII-DNA transient covalent complex, inducing double stranded DNA damage and cellular death via apoptosis in cancer cells. Despite their effectiveness the topoII poisons are known to induce secondary malignancies in a small population of patients, stimulating the search for new compounds with less toxicity. Recently a small library of substituted 9-aminoacridine derivatives was discovered that displayed topoII catalytic inhibitory properties. In this work we assess their ability to inhibit proliferation and induce cellular death in SCLC. The results indicate effective inhibition of cellular proliferation at EC(50) values in the low μM range. Western blot analysis of p62/LC3 levels, the AKT/mTOR pathway, and the ERK1/2 pathway indicate that autophagy is occurring as the primary mechanism of cell death; furthermore, the Guava Nexin and caspase 3/7 activation assays indicate that apoptosis does not occur. While it is unlikely that the active concentration of these compounds could be achieved in vivo, they show great promise for the use and effectiveness of acridine derivatives in the treatment of SCLC in the future.
Insights
New acridine derivatives show promise for treating small cell lung cancer (SCLC) by inhibiting cell proliferation. These compounds induce cell death primarily through autophagy, not apoptosis, offering a potentially less toxic alternative to current topoisomerase II (TopoII) poisons.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Topoisomerase II (TopoII) is crucial for DNA replication and transcription and is a key target in small cell lung cancer (SCLC) chemotherapy.
- Current SCLC treatments use TopoII poisons, which can cause DNA damage but also lead to secondary malignancies.
- There is a need for novel SCLC therapeutics with improved safety profiles.
Purpose of the Study:
- To evaluate the efficacy of novel substituted 9-aminoacridine derivatives as potential SCLC treatments.
- To determine the mechanism of cell death induced by these acridine derivatives in SCLC cells.
Main Methods:
- Assessing the inhibition of SCLC cellular proliferation by acridine derivatives.
- Utilizing Western blot analysis to examine p62/LC3, AKT/mTOR, and ERK1/2 pathways.
- Employing Guava Nexin and caspase 3/7 activation assays to detect apoptosis.
Main Results:
- Acridine derivatives effectively inhibited SCLC cell proliferation with EC50 values in the low micromolar range.
- Western blot analysis indicated that autophagy was the primary mechanism of cell death.
- Apoptosis assays confirmed that apoptosis did not occur in response to the compounds.
Conclusions:
- Substituted 9-aminoacridine derivatives demonstrate significant potential for SCLC treatment due to their antiproliferative effects.
- The primary mechanism of cell death induced by these compounds is autophagy, suggesting a different therapeutic pathway than conventional TopoII poisons.
- While in vivo concentrations may be a limitation, acridine derivatives represent a promising class of compounds for future SCLC drug development.
