Special Issue "Cisplatin in Cancer Therapy: Molecular Mechanisms of Action 3.0"

Natural product mitigation of ferroptosis in platinum-based chemotherapy toxicity: targeting the underpinning oxidative signaling pathways

OBJECTIVES

Platinum-based anticancer chemotherapy (PAC) represents a cornerstone in cancer treatment, retaining its status as the gold standard therapy. However, PAC's efficacy is countered by significant toxicities, such as nephrotoxicity, ototoxicity, and neurotoxicity. Recent studies have linked these toxicities to ferroptosis, characterized by iron accumulation, reactive oxygen species generation, and lipid peroxidation. This review explores the mechanisms underlying PAC-induced toxicities, focusing on the involvement of ferroptosis with three major PAC drugs-cisplatin, carboplatin, and oxaliplatin. Further, we provide a comprehensive analysis of the natural product mitigation of PAC-induced ferroptotic toxicity.

KEY FINDINGS

The mechanistic role of ferroptosis in cisplatin- and oxaliplatin-induced toxicities has been investigated, while studies on carboplatin-induced ferroptotic toxicities are lacking. Natural compounds targeting molecular pathways of ferroptosis have been explored to mitigate PAC-induced ferroptotic toxicity.

CONCLUSION

While ferroptosis in cisplatin- and oxaliplatin-induced toxicities has been investigated, there remains a notable dearth of studies examining its involvement in carboplatin-induced toxicities. Hence, further exploration is warranted to define the role of ferroptosis in carboplatin-induced toxicities, and its further mitigation. Moreover, in-depth mechanistic evaluation is necessary to establish natural products evaluated against PAC-induced ferroptosis, as PAC adjuvants.

Hydrazide-Based Class I Selective HDAC Inhibitors Completely Reverse Chemoresistance Synergistically in Platinum-Resistant Solid Cancer Cells

In this work, we have synthesized a set of peptoid-based histone deacetylase inhibitors (HDACi) with a substituted hydrazide moiety as zinc-binding group. Subsequently, all compounds were evaluated in biochemical HDAC inhibition assays and for their antiproliferative activity against native and cisplatin-resistant cancer cell lines. The hydrazide derivatives with a propyl or butyl substituent (compounds 5 and 6) emerged as the most potent class I HDAC selective inhibitors (HDAC1-3). Further, compounds 5 and 6 outperformed entinostat in cytotoxicity assays and were able to reverse chemoresistance in cisplatin-resistant A2780 (ovarian) and Cal27 (head-neck) cancer cell lines. Moreover, the hydrazide derivatives 5 and 6 showed strong synergism with cisplatin (combination indices <0.2), again outperforming entinostat, and increased DNA damage, p21, and pro-apoptotic BIM expression, leading to caspase-mediated apoptosis and cell death. Thus, compounds 5 and 6 represent promising lead structures for developing new HDACi capable of reversing chemoresistance in cisplatin resistant cancer cells.

Genetic origins, regulators, and biomarkers of cellular senescence

This review comprehensively examines the molecular biology and genetic origins of cellular senescence. We focus on various cellular stressors and pathways leading to senescence, including recent advances in the understanding of the genetic influences driving senescence, such as telomere attrition, chemotherapy-induced DNA damage, pathogens, oncogene activation, and cellular and metabolic stress. This review also highlights the complex interplay of various signaling and metabolic pathways involved in cellular senescence and provides insights into potential therapeutic targets for aging-related diseases. Furthermore, this review outlines future research directions to deepen our understanding of senescence biology and develop effective interventions targeting senescent cells (SnCs).

Synthesis and Antiproliferative Activity of Cisplatin-3-Chloropiperidine Conjugates

We report the synthesis and characterization of two novel cisplatin- alkylating agents conjugates. Combining a platinum based cytostatic agent with a sterically demanding alkylating agent could potentially induce further DNA damage, block cell repair mechanisms and keep the substrate active against resistant tumor cell lines. The 3-chloropiperidines utilized as ligands in this work are cyclic representatives of the N-mustard family and were not able to coordinate platinum on their own. The introduction of a second coordination site, in form of a pyridine moiety, led to the isolation of the desired conjugates. They were characterized with HRMS, CHN-analyses and XRD. We concluded this work by examining the cytotoxicity of the ligands and the obtained complexes with MTT assays in human cancer cell lines. While the ligands showed hardly any activity, the novel conjugates both displayed a high antiproliferative and cytotoxic potency in a panel of three cell lines. Moreover, both complexes were able to largely circumvent the acquired cisplatin resistance of A2780cisR ovarian cancer cells, both in the MTT assay and a flow-cytometric apoptosis assay.

Identifying Factors Contributing to Delayed Diagnosis of Ovarian Cancer: A Comprehensive Analysis

Background

Ovarian cancer (OC) remains the deadliest gynecologic malignancy worldwide due to delayed diagnosis, recurrence, and drug resistance. This study aimed to identify key factors affecting delayed diagnosis in OC patients.

Methods

A retrospective analysis was conducted on OC patients treated at Taihe Hospital, Hubei University of Medicine from June 2023 to September 2023. Patients were categorized based on a three-months cut-off point for delayed diagnosis. Collected data included demographics, tumor incidence, and disease cognition. The analysis of variance and the chi-squared test was used for comparison between groups.

Results

The significant differences were found in age, residence, education level, family income, family history of tumor, histology, FIGO stage, and tumor location between groups (P<0.05). Multifactorial logistic regression analysis identified education level [odds ratio (OR) = 0.606; 95% confidence interval (CI): 0.440, 0.833; P = 0.002], family history of tumor (OR = 0.462; 95% CI: 0.214, 0.997; P = 0.049), emotional barriers (OR = 1.332; 95% CI: 1.081, 1.642; P = 0.007), and practical barriers (OR = 2.964; 95% CI: 2.195, 4.004; P < 0.001) as risk factors for delayed diagnosis of OC.

Conclusion

Patient cognition is crucial in OC diagnosis delay. Enhancing public awareness and understanding of OC is essential to eliminate fear and improve early diagnosis.

A G-quadruplex-binding platinum complex induces cancer mitochondrial dysfunction through dual-targeting mitochondrial and nuclear G4 enriched genome

BACKGROUND

G-quadruplex DNA (G4) is a non-canonical structure forming in guanine-rich regions, which play a vital role in cancer biology and are now being acknowledged in both nuclear and mitochondrial (mt) genome. However, the impact of G4-based targeted therapy on both nuclear and mt genome, affecting mt function and its underlying mechanisms remain largely unexplored.

METHODS

The mechanisms of action and therapeutic effects of a G4-binding platinum(II) complex, Pt-ttpy, on mitochondria were conducted through a comprehensive approaches with in vitro and in vivo models, including ICP-MS for platinum measurement, PCR-based genetic analysis, western blotting (WB), confocal microscope for mt morphology study, extracellular flux analyzer, JC1 and Annexin V apoptosis assay, flow cytometry and high content microscope screening with single-cell quantification of both ROS and mt specific ROS, as well as click-chemistry for IF study of mt translation. Decipher Pt-ttpy effects on nuclear-encoded mt related genes expression were undertaken via RNA-seq, Chip-seq and CUT-RUN assays.

RESULTS

Pt-ttpy, shows a highest accumulation in the mitochondria of A2780 cancer cells as compared with two other platinum(II) complexes with no/weak G4-binding properties, Pt-tpy and cisplatin. Pt-ttpy induces mtDNA deletion, copy reduction and transcription inhibition, hindering mt protein translation. Functional analysis reveals potent mt dysfunction without reactive oxygen species (ROS) induction. Mechanistic study provided first evidence that most of mt ribosome genes are highly enriched in G4 structures in their promoter regions, notably, Pt-ttpy impairs most nuclear-encoded mt ribosome genes' transcription through dampening the recruiting of transcription initiation and elongation factors of NELFB and TAF1 to their promoter with G4-enriched sequences. In vivo studies show Pt-ttpy's efficient anti-tumor effects, disrupting mt genome function with fewer side effects than cisplatin.

CONCLUSION

This study underscores Pt-ttpy as a G4-binding platinum(II) complex, effectively targeting cancer mitochondria through dual action on mt and nuclear G4-enriched genomes without inducing ROS, offering promise for safer and effective platinum-based G4-targeted cancer therapy.

(Pentamethylcyclopentadienyl)chloridoiridium(III) Complex Bearing Bidentate Ph2PCH2CH2SPh-κP,κS Ligand

The (pentamethylcyclopentadienyl)chloridoiridium(III) complex bearing a κP,κS-bonded Ph2PCH2CH2SPh ligand ([Ir(η5-C5Me5)Cl(Ph2P(CH2)2SPh-κP,κS)]PF6, (1)] was synthesized and characterized. Multinuclear (1H, 13C and 31P) NMR spectroscopy was employed for the determination of the structure. Moreover, SC-XRD confirmed the proposed structure belongs to the "piano stool" type. The Hirshfeld surface analysis outlined the most important intermolecular interactions in the structure. The crystallographic structure was optimized at the B3LYP-D3BJ/6-311++G(d,p)(H,C,P,S,Cl)/LanL2DZ(Ir) level of theory. The applicability of this level was verified through a comparison of experimental and theoretical bond lengths and angles, and 1H and 13C NMR chemical shifts. The Natural Bond Orbital theory was used to identify and quantify the intramolecular stabilization interactions, especially those between donor atoms and Ir(III) ions. Complex 1 was tested on antitumor activity against five human tumor cell lines: MCF-7 breast adenocarcinoma, SW480 colon adenocarcinoma, 518A2 melanoma, 8505C human thyroid carcinoma and A253 submandibular carcinoma. Complex 1 showed superior antitumor activity against cisplatin-resistant MCF-7, SW480 and 8505C cell lines. The mechanism of tumoricidal action on 8505C cells indicates the involvement of caspase-induced apoptosis, accompanied by a considerable reduction in ROS/RNS and proliferation potential of treated cells.

DNA Interaction with Coordination Compounds of Cd(II)containing 1,10-Phenanthroline

The experimental study of the DNA interaction with three cadmium coordination compounds [Cd(phen)3](CH3CO2)2, [Cd(phen)2(H2O)2](CH3CO2)2, and [Cd2(phen)4(H2O)2](CH3CO2)4 was carried out using spectrophotometry, viscosity, and dynamic light scattering methods. The role of the solution ionic strength (concentration of NaCl) was analyzed. All compounds can penetrate (fully or partly) to the major or minor DNA grooves. It was shown that, in addition to the important role of electrostatic interactions in the formation of the complex, intercalation of the 1,10-phenanthroline ligand occurs for compounds [Cd(phen)2(H2O)2](CH3CO2)2 and [Cd2(phen)4(H2O)2](CH3CO2)4. Compound [Cd(phen)3](CH3CO2)2 binds to DNA externally. The coordination bond between cadmium and DNA was formed in DNA complexes with [Cd2(phen)4(H2O)2](CH3CO2)4. Preliminary computer modeling of the DNA interaction with the compounds used was performed.