Oxaliplatin and [Pt(R,R-DACH)(panobinostat-2H)] show nanomolar cytotoxicity towards diffuse intrinsic pontine glioma (DIPG)

We report the synthesis of two novel platinum(ii) complexes which incorporate histone deacetylase (HDAC) inhibitors: [Pt^II(R,R-DACH)(Sub_-H)] (1), [Pt^II(R,R-DACH)(panobinostat_-2H)] (2), where SubH = suberoyl-bis-hydroxamic acid; DACH = (1R,2R)-(-)-1,2-diaminocyclohexane and panobinostat = (E)-N-hydroxy-3-[4-[[2-(2-methyl-1H-indol-3-yl)ethylamino]methyl]phenyl]prop-2-enamide. Complexes 1 and 2 were characterised by ¹H, ¹³C, ¹⁹⁵Pt NMR spectroscopy and ESI-MS. Whilst oxaliplatin demonstrated considerable cytotoxicity in two patient-derived low-passage paediatric glioma DIPG cell lines (IC₅₀ values of 0.333 μM in SU-DIPG-IV, and 0.135 μM in SU-DIPG-XXI), complex 2 showed even greater cytotoxicities, with IC₅₀ values of 0.021 μM (SU-DIPG-IV), 0.067 μM (BIOMEDE 194) and 0.009 μM (SU-DIPG-XXI). Complex 2 also demonstrated superior aqueous solubility in comparison to panobinostat. Complex 2 released free intact panobinostat under HPLC conditions, as determined by ESI-MS. Incubation of solutions of oxaliplatin (H₂O) and panobinostat (DMF) resulted in instantaneous reactivity and precipitation of a panobinostat derivative which was not a platinum complex; the same reactivity was not observed between carboplatin and panobinostat.

Toward Multi-Targeted Platinum and Ruthenium Drugs-A New Paradigm in Cancer Drug Treatment Regimens?

While medicinal inorganic chemistry has been practised for over 5000 years, it was not until the late 1800s when Alfred Werner published his ground-breaking research on coordination chemistry that we began to truly understand the nature of the coordination bond and the structures and stereochemistries of metal complexes. We can now readily manipulate and fine-tune their properties. This had led to a multitude of complexes with wide-ranging biomedical applications. This review will focus on the use and potential of metal complexes as important therapeutic agents for the treatment of cancer. With major advances in technologies and a deeper understanding of the human genome, we are now in a strong position to more fully understand carcinogenesis at a molecular level. We can now also rationally design and develop drug molecules that can either selectively enhance or disrupt key biological processes and, in doing so, optimize their therapeutic potential. This has heralded a new era in drug design in which we are moving from a single- toward a multitargeted approach. This approach lies at the very heart of medicinal inorganic chemistry. In this review, we have endeavored to showcase how a "multitargeted" approach to drug design has led to new families of metallodrugs which may not only reduce systemic toxicities associated with modern day chemotherapeutics but also address resistance issues that are plaguing many chemotherapeutic regimens. We have focused our attention on metallodrugs incorporating platinum and ruthenium ions given that complexes containing these metal ions are already in clinical use or have advanced to clinical trials as anticancer agents. The "multitargeted" complexes described herein not only target DNA but also contain either vectors to enable them to target cancer cells selectively and/or moieties that target enzymes, peptides, and intracellular proteins. Multitargeted complexes which have been designed to target the mitochondria or complexes inspired by natural product activity are also described. A summary of advances in this field over the past decade or so will be provided.

Crystal structure of catena-poly[diaqua-bis(di(N 2,N 6-dihydroxypyridine-2,6-dicarboxamide))potassium(I)]tetrahydrate, C14H25N6O14K

C14H25N6O14K, triclinic, P1̅ (no. 2), a = 6.9630(15) Å, b = 9.2770(17) Å, c = 9.6100(18) Å, α = 69.822(2)°, β = 87.225(2)°, γ = 85.559(2)°, V = 580.8(2) Å3, Z = 1, R gt(F) = 0.0366, wR ref(F 2) = 0.1052, T = 293(2) K.

Crystal structure of N-hy-droxy-picolinamide monohydrate

The crystal structure of the title compound, C6H6N2O2·H2O, consists of N-hy-droxy-picolinamide and water mol-ecules connected through O-H⋯O and N-H⋯N hydrogen bonds. The O-H⋯O inter-actions and π-π stacking inter-actions between the pyridine rings [centroid-centroid distance = 3.427 (1) Å] organize the components into columns extending along the b axis and the N-H⋯N hydrogen bonds link these columns into a two-dimensional framework parallel to (100). The N-hy-droxy-picolinamide mol-ecule adopts a strongly flattened conformation and only the O-H group H atom deviates significantly from the mol-ecule best plane. The dihedral angle between the hydroxamic group and the pyridine ring is 5.6 (2)°. The conformation about the hydroxamic group C-N bond is Z and that about the C-C bond between the pyridine and hydroxamic groups is E.

Novel trans-platinum complexes of the histone deacetylase inhibitor valproic acid; synthesis, in vitro cytotoxicity and mutagenicity

The first examples of Pt complexes of the well known anti-epilepsy drug and histone deacetylase inhibitor, valproic acid (VPA), are reported. Reaction of the Pt(II) am(m)ine precursors trans-[PtCl(2)(NH(3))(py)] and trans-[PtCl(2)(py)(2)] with silver nitrate and subsequently sodium valproate gave trans-[Pt(VPA(-1H))(2)(NH(3))(py)] and trans-[Pt(VPA(-1H))(2)(py)(2)], respectively. The valproato ligands in both complexes are bound to the Pt(II) centres via the carboxylato functionality and in a monodentate manner. The X-ray crystal structure of trans-[Pt(VPA(-1H))(2)(NH(3))(py)] is described. Replacement of the dichlorido ligands in trans-[PtCl(2)(py)(2)] and trans-[PtCl(2)(NH(3))(py)] by valproato ligands (VPA(-1H)) to yield trans-[Pt(VPA(-1H))(2)(py)(2)] and trans-[Pt(VPA(-1H))(2)(NH(3))(py)] respectively, significantly enhanced cytotoxicity against A2780 (parental) and A2780 cisR (cisplatin resistant) ovarian cancer cells. The mutagenicity of trans-[Pt(VPA(-1H))(2)(NH(3))(py)] and trans-[Pt(VPA(-1H))(2)(py)(2)] was determined using the Ames test and is also reported.