Targeting RAS-RAF pathway significantly improves antitumor activity of Rigosertib-derived platinum(IV) complexes and overcomes cisplatin resistance

Pt(IV) Complexes in the Search for Novel Platinum Prodrugs with Promising Activity

The kinetically inert, six coordinated, octahedral Pt(IV) complexes are termed dual-, triple-, or multi-action prodrugs based on the nature of the axially substituted ligands. These ligands are either inert or biologically active, where the nature of these axial ligands provides additional stability, synergistic biological activity or cell-targeting ability. There are many literature reports from each of these classes, mentioning the varied nature of these axial ligands. The ligands comprise drug molecules such as chlorambucil, doxorubicin, valproic acid, ethacrynic acid, biologically active chalcone, coumarin, combretastatin, non-steroidal anti-inflammatory drugs (NSAIDs) and many more, potentiating the anti-proliferative profile or reducing the side effects associated with cisplatin therapy. The targeting and non-targeting nature of these moieties exert additive or synergistic effects on the anti-cancer activity of Pt(II) moieties. Herein, we discuss the effects of these axially oriented ligands and the changes in the non-leaving am(m)ine groups and in the leaving groups on the biological activity. In this review, we have presented the latest developments in the field of Pt(IV) complexes that display promising activity with a reduced resistance profile. We have discussed the structure activity relationship (SAR) and the effects of the ligands on the biological activity of Pt(IV) complexes with cisplatin, oxaliplatin, carboplatin and the Pt core other than approved drugs. This literature work will help researchers to get an idea about Pt(IV) complexes that have been classified based on the aspects of their biological activity.

Novel Platinum(IV) complexes intervene oxaliplatin resistance in colon cancer via inducing ferroptosis and apoptosis

Platinum-based chemotherapeutics are widely used for cancer treatment but are frequently limited because of dosage-dependent side effects and drug resistance. To attenuate these drawbacks, a series of novel platinum(IV) prodrugs (15a-18c) were synthesized and evaluated for anti-cancer activity. Among them, 17a demonstrated superior anti-proliferative activity compared with oxaliplatin (OXA) in the cisplatin-resistant lung cancer cell line A549/CDDP and OXA-resistant colon cancer cell line HCT-116/OXA but showed a lower cytotoxic effect toward human normal cell lines HUVEC and L02. Mechanistic investigations suggested that 17a efficiently enhanced intracellular platinum accumulation, induced DNA damage, disturbed the homeostasis of intracellular reactive oxygen molecules and mitochondrial membrane potential, and thereby activated the mitochondrion-dependent apoptosis pathway. Moreover, 17a significantly induced ferroptosis in HCT-116/OXA via triggering the accumulation of lipid peroxides, disrupting iron homeostasis, and inhibiting solute carrier family 7 member 11 and glutathione peroxidase 4 axial pathway transduction by inhibiting the expression of the phosphorylated signal transducer and activator of transcription 3 and nuclear factor erythroid 2-related factor 2. Moreover, 17a exerted remarkable in vivo antitumor efficacy in the HCT-116/OXA xenograft models but showed attenuated toxicity. These results indicated that these novel platinum(IV) complexes provided an alternative strategy to develop novel platinum-based antineoplastic agents for cancer treatment.

CAB39 promotes cisplatin resistance in bladder cancer via the LKB1-AMPK-LC3 pathway

Systemic therapy for muscle-invasive bladder cancer (BC) remains dominated by cisplatin-based chemotherapy. However, resistance to cisplatin therapy greatly limits long-term survival. Resistance to cisplatin-based chemotherapy still needs to be addressed. In this study, we established three cisplatin-resistant BC cell lines by multiple cisplatin pulse treatments. Interestingly, after exposure to cisplatin, all cisplatin-resistant cell lines showed lower reactive oxygen species (ROS) levels than the corresponding parental cell lines. Using proteomic analysis, we identified 35 proteins that were upregulated in cisplatin-resistant BC cells. By knocking down eleven of these genes, we found that after CAB39 knockdown, BC cisplatin-resistant cells were more sensitive to cisplatin. Overexpression of CAB39 had the opposite effect. Then, the knockdown of six genes downstream of CAB39 revealed that CAB39 promoted cisplatin resistance in BC through LKB1. Moreover, a key cause of cisplatin-induced cell death is damage to mitochondria and increased ROS levels. In our study, cisplatin-resistant cells exhibited higher autophagic flux and healthier mitochondrial status after cisplatin exposure. We demonstrated that the CAB39-LKB1-AMPK-LC3 pathway plays a critical role in enhancing autophagy to maintain the health of mitochondria and reduce ROS levels. In addition, the autophagy inhibitor chloroquine (CQ) can significantly enhance the killing effect of cisplatin on BC cells. Compared with gemcitabine plus cisplatin (GC), GC plus CQ significantly reduced tumor burden in vivo. In conclusion, our study shows that CAB39 counteracts the killing of cisplatin by enhancing the autophagy of BC cells to damaged mitochondria and other organelles to alleviate the damage of cells caused by harmful substances such as ROS.

Hydrazylpyridine salicylaldehyde-copper(II)-1,10-phenanthroline complexes as potential anticancer agents: synthesis, characterization and anticancer evaluation

We synthesized and analyzed nine unique copper(II) hydrazylpyridine salicylaldehyde and 1,10-phenanthroline complexes, [Cu(L1a)(phen)] (Cugdupt1), [Cu(L2a)(phen)]·(CH3CN) (Cugdupt2), [Cu(L3a)(phen)] (Cugdupt3), [Cu(L4a)(phen)]·(CH3CN) (Cugdupt4), [Cu(L5a)(phen)] (Cugdupt5), [Cu(L6a)(phen)] (Cugdupt6), [Cu(L7a)(phen)] (Cugdupt7) [Cu(L8a)(phen)] (Cugdupt8) and [Cu(L9a)(phen)]·0.5(H2O) (Cugdupt9). We were motivated by the intriguing properties of the coupled ligands of hydrazylpyridine, salicylaldehyde, and 1,10-phenanthroline. The MTT assay demonstrated that Cugdupt1-Cugdupt9 have higher anticancer activity than L1H2-L9H2, phen and cisplatin on A549/DDP cancer cells (A549cis). Cugdupt1-Cugdupt9 were superior to cisplatin with IC50 values of 1.6-100.0 fold on A549cis cells (IC50(Cugdupt1-Cugdupt9) = 0.5-30.5 μM, IC50(cisplatin) = 61.5 ± 1.0 μM). However, Cugdupt1-Cugdupt9 had lower cytotoxicity toward the HL-7702 normal cells. Cugdupt1 and Cugdupt8 can induce reduction of mitochondrial respiratory chain complexes I/IV (MRCC-I/IV), mitophagy pathways, and eventually protein regulation and adenosine triphosphate (ATP) depletion in A549cis cells. The findings indicated that Cugdupt1 and Cugdupt8 caused cell death via both ATP diminution and mitophagy pathways. Finally, Cugdupt8 demonstrated high efficacy and no obvious cytotoxicity in A549 tumor-bearing mice. This study thus helps evaluate the potential of the hydrazylpyridine salicylaldehyde-copper(II)-1,10-phenanthroline compounds for cisplatin-resistant tumor therapy.

Metal-Based Complexes in Cancer

Metal-based drugs have attracted growing interest in biomedicine [...].

Lights and Shadows on the Cancer Multi-Target Inhibitor Rigosertib (ON-01910.Na)

Rigosertib (ON-01910.Na) is a small-molecule member of the novel synthetic benzyl-styryl-sulfonate family. It is currently in phase III clinical trials for several myelodysplastic syndromes and leukemias and is therefore close to clinical translation. The clinical progress of rigosertib has been hampered by a lack of understanding of its mechanism of action, as it is currently considered a multi-target inhibitor. Rigosertib was first described as an inhibitor of the mitotic master regulator Polo-like kinase 1 (Plk1). However, in recent years, some studies have shown that rigosertib may also interact with the PI3K/Akt pathway, act as a Ras-Raf binding mimetic (altering the Ras signaling pathway), as a microtubule destabilizing agent, or as an activator of a stress-induced phospho-regulatory circuit that ultimately hyperphosphorylates and inactivates Ras signaling effectors. Understanding the mechanism of action of rigosertib has potential clinical implications worth exploring, as it may help to tailor cancer therapies and improve patient outcomes.

Novel 4-Amino-Quinazoline Moieties Ligated Platinum(IV) Prodrugs Overcome Cisplatin Resistance in EGFRWT Human Lung Cancer

Developing bioactive axial ligands ligated platinum(IV) complexes with advantages over monotherapy and drug combinations is an efficient strategy to ameliorate the clinical defects of platinum(II) drugs. In this article, a series of 4-amino-quinazoline moieties (privileged pharmacophores of well-studied EGFR inhhibitors) ligated platinum(IV) were synthesized and evaluated for their anticancer activities. Among the complex, 17b demonstrated higher cytotoxicity against the tested lung cancer cells (including CDDP-resistant A549/CDDP cells) while lower cytotoxicity toward human normal cells than Oxaliplatin (Oxa) or cisplatin (CDDP). Mechanistic investigation demonstrated that the enhanced intracellular uptake of 17b efficiently elevated the of reactive oxygen species levels by 6.1 times more than Oxa. Detailed mechanisms of overcoming CDDP resistance revealed that 17b significantly induced apoptosis via inducing severe DNA damage, disturbing mitochondrial transmembrane potentials, efficiently disturbing EGFR-PI3K-Akt signaling transduction and activating a mitochondria-dependent apoptosis pathway. Besides, 17b significantly inhibited migration and invasion in A549/CDDP cells. In vivo tests exhibited that 17b obtained superior antitumor effect and attenuated systemic toxicity in A549/CDDP xenografts. All these results emphasized that the antitumor action of 17b differed from that of. classical platinum(II) drugs and provided a novel practical method to overcome CDDP resistance in lung cancer.

Dual-target platinum(IV) complexes reverse cisplatin resistance in triple negative breast via inhibiting poly(ADP-ribose) polymerase (PARP-1) and enhancing DNA damage

Platinum(II)-based drugs play an important role in many chemotherapeutic protocols, but their further clinical applications are hindered by the development of drug resistance and serious side effects. Therefore, to reverse cisplatin (CDDP) resistance in tandem with reduced side effects, nine novel platinum(IV) complexes modified with key pharmacophore of Olaparib were synthesized and evaluated for biological activities. Among them, the optimal complex 8-2 showed good inhibitory activity against PARP-1 and superior anticancer effects over CDDP on parental (MDA-MB-231, IC₅₀ = 1.13 μM) and CDDP -resistant triple-negative breast cancer (TNBC) cell line (MDA-MB-231/CDDP, IC₅₀ = 1.72 μM). Detailed mechanisms revealed that compared with Olaparib and CDDP, the enhanced intracellular accumulation of 8-2 could efficiently reverse CDDP resistance in MDA-MB-231/CDDP cells via inhibiting DNA repair-associated mechanisms, enhancing DNA damage, and activating mitochondrion-dependent apoptosis pathway. Furthermore, 8-2 obtained higher tumor growth inhibition rate (64.1 %) than CDDP (26.5 %) in MDA-MB-231/CDDP xenografts, but it did not induce significant toxicity in vivo and in intro, making it a potential drug candidate for the treatment of TNBC.

The role of Platinum(IV)-based antitumor drugs and the anticancer immune response in medicinal inorganic chemistry. A systematic review from 2017 to 2022

Platinum-based antitumor drugs have been used in many types of tumors due to its broad antitumor spectrum in clinic. Encouraged by the cisplatin's (CDDP) worldwide success in cancer chemotherapy, the research in platinum-based antitumor drugs has evolved from traditional platinum drug to multi-ligand and multifunctional platinum prodrugs over half a century. With the rapid development of metal drugs and the anticancer immune response, challenges and opportunities in platinum drug research have been shifted from traditional platinum-based drugs to platinum-based hybrids and the direction of development is tending toward photodynamic therapy, nano-delivery therapy, drug combination, targeted therapy, diagnostic therapy, immune-combination therapy and tumor stem cell therapy. In this review, we first exhaustively overviewed the role of platinum-based antitumor prodrugs and the anticancer immune response in medicinal inorganic chemistry based on the special nanomaterials, the modification of specific ligands, and the multiple functions obtained that are beneficial for tumor therapy in the last five years. We also categorized them according to drug potency and function. There hasn't been a comprehensive evaluation of precursor platinum drugs in prior articles. And a multifarious approach to distinguish and detail the variety of alterations of platinum-based precursors in various valence states also hasn't been summarized. In addition, this review points out the main problems at the interface of chemistry, biology, and medicine from their action mechanisms for current platinum drug development, and provides up-to-date potential strategies from drug design perspectives to circumvent those drawbacks. And a promising idea is also enlightened for researchers in the development and discovery of platinum prodrugs.

Potential Anticancer Activities and Catalytic Oxidation Efficiency of Platinum(IV) Complex

The treatment of an aqueous acetonitrile solution of chloroplatinic acid hydrate H₂PtCl₆.xH₂O and pyridine-2-carbaldehyde-oxime (paOH) in the presence of potassium thiocyanate at room temperature (25°) led to the formation of a new Pt(IV) complex with the formula [Pt(SCN)₂(paO)₂], (1). Complex 1 was fully characterized by FT-IR, UV-vis and NMR spectroscopic techniques as well as elemental analysis. The crystallographic structure of complex 1 was obtained by single-crystal X-ray diffraction. The structure of complex 1 consists of a distorted octahedral geometrical environment around the platinum center in which the coordination sites are occupied by two terminal thiocyanate ligands in trans arrangement and two bidentate paO ligands through four nitrogen atoms. In addition, the in vitro evaluation of the cytotoxicity of platinum complex 1 against four different cancer cell lines was performed. The IC₅₀ values for colon (HCT116), liver (HepG2), breast (MCF-7) and erythroid (JK-1) treated with complex 1 are 19 ± 6, 21 ± 5, 22 ± 6, and 13 ± 3 μM, respectively. In HCT116 cells treated with the IC50 dose of our title compound, apoptosis and necrosis were increased by 34% and 27.8%, respectively. Cells halted in the proliferative phase (S phase) to 21.7 % and 29.8% in HCT116 and HepG2 cells treated with complex 1 have anti-proliferative actions. Furthermore, the catalytic activity of synthesized complex 1 was examined in the oxidation reaction of benzyl alcohols in the presence of an oxidant. Finally, the luminescence behavior of complex 1 was investigated.

Blood-Brain Barrier Permeable and NO-Releasing Multifunctional Nanoparticles for Alzheimer's Disease Treatment: Targeting NO/cGMP/CREB Signaling Pathways

The development of novel therapeutic strategies for combating Alzheimer's disease (AD) is challenging but imperative. Multifunctional nanoparticles are promising tools for regulating complex pathological dysfunctions for AD treatment. Herein, we constructed multifunctional nanoparticles consisting of regadenoson (Reg), nitric oxide (NO) donor, and YC-1 in a single molecular entity that can spontaneously self-assemble into nanoparticles and load donepezil to yield Reg-nanoparticles (Reg-NPs). The Reg moiety enabled the Reg-NPs to effectively regulate tight junction-associated proteins in the blood-brain barrier, thus facilitating the permeation of donepezil through the barrier and its accumulation in the brain. Moreover, the released NO and YC-1 activated the NO/cGMP/CREB signaling pathway by stimulating soluble guanylyl cyclase and inhibiting phosphodiesterase activity, which finally reduced cytotoxicity induced by aggregated Aβ in the neurons and was beneficial for synaptic plasticity and memory formation.

Dual-target platinum(IV) complexes exhibit antiproliferative activity through DNA damage and induce ER-stress-mediated apoptosis in A549 cells

Platinum(II)-based chemotherapeutics are commonly used to treat various types of solid tumors, such as lung cancers. However, these compounds can cause serious side effects, including nephrotoxicity and ototoxicity, which affect the quality of life of patients. In our work, four novel dual target platinum(IV) complexes were designed and synthesized. In vitro results indicated that the title platinum(IV) complexes exhibited effective antitumor activities against the tested cancer cells and had lower toxicity and resistance factors than oxaliplatin and cisplatin. Further mechanistic experiments demonstrated that complex 11 accumulated in mitochondria and induced an elevation in ROS and an ER stress response via mitochondrial dysfunction. Notably, complex 11 significantly modulated the expression levels of proapoptosis proteins including cleaved-Caspase-3, Bax, and p53, and decreased the level of the prosurvival protein Bcl-2. Together, these results suggested that complex 11 might be a potential lead compound for future cancer therapy due to its potency and selectivity.

Platinum(IV) complexes conjugated with chalcone analogs as dual targeting anticancer agents: In vitro and in vivo studies

For the sake to develop novel platinum(IV) complexes to reverse cisplatin (CDDP) resistence, four multifunctional platinum(IV) prodrugs via conjugating chalcones with the related platinum(IV) complexes derived from cisplatin were designed and evaluated for anti-tumor actyivities in vitro and in vivo. Among them, complex 9 exhibited excellent anticancer activities in vitro with IC₅₀ values at the submicromolar level against the tested human cancer cells, whereas showed low cytotoxicity towards human normal liver cells HL-7702. Further mechanistic studies indicated that complex 9 induced G2/M phase arrest and apoptosis in A549 cells, which was associated with a collapse of the mitochondrial membrane potential (MMP), alterations in the expression of some apoptosis-related proteins, and enhanced level of the intracellular reactive oxygen species (ROS). More importantly, complex 9 significantly suppressed the tumor growth in the A549 xenograft model without obvious hints of toxicity.