Platination of cysteine by an epidermal growth factor receptor kinase-targeted hybrid agent

Metal complexes bearing EGFR-inhibiting ligands as promising anticancer agents

Overexpression of the epidermal growth factor receptor (EGFR, erbB1) has been observed in a wide range of solid tumors and has frequently been associated with poor prognosis. As a result, EGFR inhibition has become an attractive anticancer drug design strategy, and a large number of small molecular inhibitors have been developed. Despite the widespread clinical use of EGFR tyrosine kinase inhibitors (TKIs), their drug resistance, inadequate accumulation in tumors, and severe side effects have spurred the search for better antitumor drugs. Metal complexes have attracted much attention because of their different mechanisms compared with EGFR-TKIs. Therefore, the combination of metals and inhibitors is a promising anticancer strategy. For example, Ru and Pt centers are introduced to design complexes with double or multiple targets, while Au complexes are combined with inhibitors to overcome drug resistance. Co complexes are designed as prodrugs with weak side effects and enhanced targeting by the hypoxia activation strategy, and other metals such as Rh and Fe enhance the anticancer effect of the complexes. In addition, the introduction of Ga center is beneficial to the development of nuclear imaging tracers. In this paper, metal EGFR-TKI complexes in the last 15 years are reviewed, their mechanisms are briefly introduced, and their advantages are summarized.

Novel design of dual-action Pt(IV) anticancer pro-drugs based on cisplatin and derivatives of the tyrosine kinase inhibitors imatinib and nilotinib

Tyrosine kinases (TKs) are emerging as important targets in cancer therapy and some of their inhibitors, TKIs (e.g. imatinib and nilotinib), are FDA-approved drugs that are used as selective anti-cancer therapeutics against cell lines that overexpress TKs. Many examples of metal-based complexes functionalised with TKIs are reported in the literature but very few have been functionalised with platinum. Here we report the design, a detailed computational analysis/simulation, the complete chemical characterisation and the preliminary biological evaluation of two novel Pt(IV) anticancer pro-drugs based on cisplatin tethered with a derivative of either imatinib or nilotinib in the axial position. Pt(IV) complexes are a strategic scaffold in combination therapy due to their axial ligands that can be functionalised to form dual action drugs. The activation by reduction releases the Pt(II) core and the axial ligands upon cellular internalisation. The antiproliferative activity and the TK inhibition properties of the novel adducts are analysed with a theoretical approach and confirmed in vitro with preliminary biological assays.

Synthesis of a New Phenyl Chlormethine-Quinazoline Derivative, a Potential Anti-Cancer Agent, Induced Apoptosis in Hepatocellular Carcinoma Through Mediating Sirt1/Caspase 3 Signaling Pathway

Quinazoline derivatives display multiple pharmacological activities and target various biological receptors. Based on the skeleton of quinazoline core, we designed and synthesized three new quinazoline-phenyl chlormethine conjugates (I–III) bearing a Schiff base (C = N) linker, and investigated their anti-tumor effects on HepG2-xenografted tumor and human cancer cell line HepG2. Among these compounds, compound II showed better inhibitory effect against HepG2 cells. In the present study, TUNEL staining, western blot, molecular docking, and siRNA were used to investigate the inhibitory mechanism of compound II towards hepatoma. Compound II inhibited HepG2-xenografted tumor growth in nude mice. Moreover, Compound II not only up-regulated Bax/Bcl-2 ratio and active-caspase 3 level, but also down-regulated Sirt1 expression and its activity, as well as PGC-1α expression. Furthermore, compound II also significantly suppressed the promotion of HepG2 cell proliferation, as evidenced by MTT assay and lactate dehydrogenase (LDH) release assay. Of note, the cytotoxicity of Compound II on HepG2 cells mainly via regulating Sirt1/caspase 3 signaling pathway, consisting with the results in vivo. Intriguingly, z-DEVD-FMK, a caspase 3 inhibitor, almost abolished the inhibitory effects of compound II. Of note, knockdown of caspase 3 by siRNA significantly reversed the inhibitory effect of compound II on HepG2. Interestingly, compound II directly bonded to Sirt1, indicating that Sirt1 might be a promising therapeutic target of compound II. In summary, our findings reveal that compound II, a new synthetical phenyl chlormethine-quinazoline derivative, contributes to the apoptosis of HepG2 cells both in vivo and in vitro through mediating Sirt1/caspase 3 singling pathway. These findings demonstrate that compound II may be a new potent agent against hepatocellular carcinoma.

Platinum(II) Terpyridine Anticancer Complexes Possessing Multiple Mode of DNA Interaction and EGFR Inhibiting Activity

Platinum(II) terpyridine complexes has attracted increasing attention as they have displayed great potential as antitumor agents due to their high intercalation affinity with nucleic acids. Epidermal growth factor receptor (EGFR) is often overexpressed in various tumor cells, leading to uncontrolled growth of tumor, and is regarded as an important target for developing novel antitumor drugs. Herein, we report four platinum(II) terpyridine complexes bearing EGFR inhibiting 4-anilinoquinazoline derivatives as potent multi-targeting antiproliferation agents against a series of cancer cells. EGFR inhibition assay revealed that these complexes are highly potent EGFR inhibitors. But competitive DNA binding assay and docking simulations also suggested that these complexes exhibited multiple modes of DNA interaction, especially great affinity toward DNA minor groove. Finally, cellular uptake and distribution measurements by inductively coupled plasma mass spectrometry (ICP-MS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) demonstrated that both nucleus DNA and membrane proteins are important targets for their anticancer mechanisms. The complexes herein can therefore be regarded as promising multi-targeting anticancer agents.

Improving the anticancer activity of platinum(iv) prodrugs using a dual-targeting strategy with a dichloroacetate axial ligand

Four novel platinum(iv) complexes, characteristic of DCA/TFA and with chloride ions as axial ligands, were designed and synthesized. This type of platinum(iv) complexes 1a–2b exhibited significant cytotoxic activity, and the cytotoxicity of 1b was the greatest among these four complexes, which was 20.61 fold and 7.65 fold higher than that of cisplatin against HepG-2 and NCI-H460 cancer cells, respectively. The result from the apoptosis assay of 1b was consistent with the result from the cytotoxicity assay. In addition, complexes 1a and 1b induced cell cycle arrest at the S phase on HepG-2 cells. Taken together, our data showed that Pt(iv) complex 1b released the corresponding Pt(ii) complex and DCA, and induced apoptosis as well as disruption of the mitochondrial membrane potential, establishing Pt(iv) complex 1b as a potential dual-targeting anticancer agent.

Complex 1b could release complex B and DCA, playing a dual-targeting anti-tumor effect against cancer cells, targeting nuclear DNA and mitochondria, respectively.

Cysteine-Directed Bioconjugation of a Platinum(II)-Acridine Anticancer Agent

Classical maleimide Michael addition chemistry in conjunction with copper-free click chemistry was investigated as a synthetic strategy to attach cytotoxic platinum-acridine hybrid agents to carrier proteins. The structural integrity and selectivity of the model payloads, which were validated in human serum albumin (HSA) using mass spectrometric analysis and heteronuclear 2D ¹H-¹⁵N HSQC NMR experiments, may have broad utility for the targeted delivery of highly cytotoxic platinum acridines and other nonclassical platinum containing anticancer agents.