Exposure of CCRF-CEM cells to acridone derivative 8a triggers tumor death via multiple mechanisms

Exploring the Physical and Biological Aspects of BNCT with a Carboranylmethylbenzo[b]acridone Compound in U87 Glioblastoma Cells

Boron neutron capture therapy (BNCT) is a re-emerging technique for selectively killing tumor cells. Briefly, the mechanism can be described as follows: after the uptake of boron into cells, the thermal neutrons trigger the fission of the boron atoms, releasing the α-particles and recoiling lithium particles and high-energy photons that damage the cells. We performed a detailed study of the reactor dosimetry, cellular dose assessment, and radiobiological effects induced by BNCT in glioblastoma (GBM) cells. At maximum reactor power, neutron fluence rates were ϕ0 = 6.6 × 107 cm−2 s−1 (thermal) and θ = 2.4 × 104 cm−2 s−1 with a photon dose rate of 150 mGy·h−1. These values agreed with simulations to within 85% (thermal neutrons), 78% (epithermal neutrons), and 95% (photons), thereby validating the MCNPX model. The GEANT4 simulations, based on a realistic cell model and measured boron concentrations, showed that >95% of the dose in cells was due to the BNC reaction. Carboranylmethylbenzo[b]acridone (CMBA) is among the different proposed boron delivery agents that has shown promising properties due to its lower toxicity and important cellular uptake in U87 glioblastoma cells. In particular, the results obtained for CBMA reinforce radiobiological effects demonstrating that damage is mostly induced by the incorporated boron with negligible contribution from the culture medium and adjacent cells, evidencing extranuclear cell radiosensitivity.

A comprehensive review on acridone based derivatives as future anti-cancer agents and their structure activity relationships

The development of drug resistance and severe side-effects has reduced the clinical efficacy of the existing anti-cancer drugs available in the market. Thus, there is always a constant need to develop newer anti-cancer drugs with minimal adverse effects. Researchers all over the world have been focusing on various alternative strategies to discover novel, potent, and target specific molecules for cancer therapy. In this direction, several heterocyclic compounds are being explored but amongst them one promising heterocycle is acridone which has attracted the attention of medicinal chemists and gained huge biological importance as acridones are found to act on different therapeutically proven molecular targets, overcome ABC transporters mediated drug resistance and DNA intercalation in cancer cells. Some of these acridone derivatives have reached clinical studies as these heterocycles have shown huge potential in cancer therapeutics and imaging. Here, the authors have attempted to compile and make some recommendations of acridone based derivatives concerning their cancer biological targets and in vitro-cytotoxicity based on drug design and novelty to increase their therapeutic potential. This review also provides some important insights on the design, receptor targeting and future directions for the development of acridones as possible clinically effective anti-cancer agents.

A review on the emerging roles of pyruvate kinase M2 in anti-leukemia therapy

Glycolysis is an important step in respiration and provides energy for cellular processes. Pyruvate kinase M2 (PKM2), a key rate-limiting enzyme of glycolysis, plays an important role in tumor cell metabolism and proliferation. It is also specifically overexpressed in leukemia cells and contributes to leukemic proliferation, differentiation, and drug resistance through both aerobic glycolysis and non-metabolic pathways. In this review, the functions and regulatory roles of PKM2 are firstly introduced. Then, the molecular mechanisms of PKM2 in leukemogenesis are summarized. Next, reported PKM2 modulators and their anti-leukemia mechanisms are described. Finally, the current challenges and the potential opportunities of PKM2 inhibitors or agonists in leukemia therapy are discussed.

Synthesis and evaluation of anticancer activity of new 9-acridinyl amino acid derivatives

A series of eleven 9-acridinyl amino acid derivatives were synthesized using a two-step procedure. Cytotoxicity was tested on the K562 and A549 cancer cell lines and normal diploid cell line MRC5 using the MTT assay. Compounds 6, 7, 8 and 9 were the most active, with IC₅₀ values comparable to or lower than that of chemotherapeutic agent amsacrine. 8 and 9 were especially effective in the A549 cell line (IC₅₀ ≈ 6 μM), which is of special interest since amsacrine is not sufficiently active in lung cancer patients. Cell cycle analysis revealed that 7 and 9 caused G2/M block, amsacrine caused arrest in the S phase, while 6 and 8 induced apoptotic cell death independently of the cell cycle regulation. In comparison to amsacrine, 6, 7, 8, and 9 showed similar inhibitory potential towards topoisomerase II, whereas only 7 showed DNA intercalation properties. In contrast to amsacrine, 6, 7, 8 and 9 showed a lack of toxicity towards unstimulated normal human leucocytes.

Comparative Proteomic Analysis of Histone Modifications upon Acridone Derivative -Induced CCRF-CEM Cells by Data Independent Acquisition

The lead compound acridone derivative 8a showed potent antiproliferative activity by inducing DNA damage through direct stacking with DNA bases and triggering ROS in CCRF-CEM cells. To define the chromatin alterations during DNA damage sensing and repair, a detailed quantitative map of single and coexisting histone post-translational modifications (PTMs) in CCRF-CEM cells affected by 8a was performed by the Data Independent Acquisition (DIA) method on QE-plus. A total of 79 distinct and 164 coexisting histone PTMs were quantified, of which 16 distinct histone PTMs were significantly altered when comparing 8a-treated cells with vehicle control cells. The changes in histone PTMs were confirmed by Western blotting analysis for three H3 and one H4 histone markers. The up-regulated dimethylation on H3K9, H3K36, and H4K20 implied that CCRF-CEM cells might accelerate DNA damage repair to counteract the DNA lesion induced by 8a, which was verified by an increment in the 53BP1 foci localization at the damaged DNA. Most of the significantly altered PTMs were involved in transcriptional regulation, including down-regulated acetylation on H3K18, H3K27, and H3K122, and up-regulated di- and trimethylation on H3K9 and H3K27. This transcription-silencing phenomenon was associated with G2/M cell cycle arrest after 8a treatment by flow cytometry. This study shows that the DIA proteomics strategy provides a sensitive and accurate way to characterize the coexisting histone PTMs changes and their cross-talk in CCRF-CEM cells after 8a treatment. Specifically, histone PTMs rearrange transcription-silencing, and cell cycle arrest DNA damage repair may contribute to the mechanism of epigenetic response affected by 8a.

Recent developments in the synthesis and biological activity of acridine/acridone analogues

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