An Antitumor Bis(N‐Heterocyclic Carbene)Platinum(II) Complex That Engages Asparagine Synthetase as an Anticancer Target

Abstract

New anticancer platinum(II) compounds with distinctive modes of action are appealing alternatives to combat the drug resistance and improve the efficacy of clinically used platinum chemotherapy. Herein, we describe arare example of an antitumor Pt II complex targeting at umor-associated protein, rather than DNA, under cellular conditions.Complex [(bis-NHC)Pt(bt)]PF 6 (1a;H bt = 1-(3-hydroxybenzo-[b]thiophen-2-yl)ethanone) overcomes cisplatin resistance in cancer cells and displays significant tumor growth inhibition in mice with higher tolerable doses compared to cisplatin. The cellular Pt species shows little association with DNA, and localizes in the cytoplasm as revealed by nanoscale secondary ion mass spectrometry.Anunbiased thermal proteome profiling experiment identified asparagine synthetase (ASNS) as am olecular target of 1a.A ccordingly, 1a treatment reduced the cellular asparagine levels and inhibited cancer cell proliferation, which could be reversed by asparagine supplementation. Ab is-NHC-ligated Pt species generated from the hydrolysis of 1a forms adducts with thiols and appears to target an active-site cysteine of ASNS.

Thermal proteome profiling for interrogating protein interactions

“…Hence, systematically monitoring changes in protein thermal stability can facilitate the understanding of various cell processes, from that of the downstream effects of drug treatment (Savitski et al , , ; Huber et al , ; Reinhard et al , ; Becher et al , ; Mateus et al , , ; Kitagawa et al , ; Azimi et al , ; Hu et al , ) to the detailed study of the eukaryotic cell cycle (Becher et al , ; Dai et al , ). This approach can be applied to multiple cellular systems—including lysates, living cells, tissues, or biological fluids—and extends beyond mammalian species.…”

“…Some of the perturbations can be applied in a dose‐dependent manner (Becher et al , ) or time‐dependent manner (Becher et al , ; Dai et al , ) to improve data analysis or facilitate mechanistic understanding of the perturbation (Fig ). Using this approach, it has been possible to deconvolute drug targets (Savitski et al , , ; Huber et al , ; Reinhard et al , ; Becher et al , ; Mateus et al , , ; Kitagawa et al , ; Azimi et al , ; Hu et al , ) and enzyme substrates (preprint: Saei et al , ), study metabolic shifts (Becher et al , ; Dai et al , ; Mateus et al , ), or identify protein–protein interactions (Tan et al , ).…”

“…By determining the melting profile of all detected proteins, TPP was initially developed to find targets and off‐targets of drug‐like molecules (Savitski et al , , ; Huber et al , ; Reinhard et al , ; Becher et al , ; Mateus et al , , ; Kitagawa et al , ; Azimi et al , ; Hu et al , ; Sridharan et al , 2019a)—generally, binding of a drug to a protein leads to a thermal stabilization of the protein (Fig ). More recently, TPP has been used to identify metabolite‐binding proteins, mapping the proteins which interact with different nucleotides (Huber et al , ; preprint: Saei et al , ; Dziekan et al , ; Sridharan et al , 2019b), and unraveling that such interactions can be both promiscuous [e.g., interactions with adenosine triphosphate (ATP)] and very specific [e.g., interactions with thymidine monophosphate (dTMP)].…”

“…More commonly, TPP experiments involve chemical [e.g., drug (Azimi et al , ; Becher et al , ; Hu et al , ; Huber et al , ; Kitagawa et al , ; Mateus et al , , ; Reinhard et al , ; Savitski et al , , ); or metabolite (preprint: Saei et al , ; Dziekan et al , ; Sridharan et al , 2019b)], genetic [e.g., gene knock‐out (Mateus et al , ; Banzhaf et al , )], or enzymatic (preprint: Saei et al , ) perturbations; or different cell states [different phase of the cell cycle (Becher et al , ; Dai et al , ), or growth phase (Mateus et al , ); Fig ]. Some of the perturbations can be applied in a dose‐dependent manner (Becher et al , ) or time‐dependent manner (Becher et al , ; Dai et al , ) to improve data analysis or facilitate mechanistic understanding of the perturbation (Fig ).…”

Correlative Light Electron Ion Microscopy revealin vivolocalisation of bedaquiline inMycobacterium tuberculosisinfected lungs

“…CLEIMiT is readily applicable to other drugs and not only for antibiotics or brominecontaining drugs but also any drugs detectable by nanoSIMS. Ion microscopy methods using nanoSIMS represents a good combination of spatial resolution and sensitivity to map drugs that contain elements other than Bromine that are low in the biological systems such as platinum [16], gold [17] and iodine [18]. What makes the approach more widely applicable is the nanoSIMS capability to detect stable isotope labelled molecules with high-resolution such as molecules that are labelled with 2 H [19,20], 13 C [19,21] and 15 N [22,23].…”