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

Experimental murine models of brainstem gliomas

As an intractable central nervous system (CNS) tumor, brainstem gliomas (BGs) are one of the leading causes of pediatric death by brain tumors. Owing to the risk of surgical resection and the little improvement in survival time after radiotherapy and chemotherapy, there is an urgent need to find reliable model systems to better understand the regional pathogenesis of the brainstem and improve treatment strategies. In this review, we outline the evolution of BG murine models, and discuss both their advantages and limitations in drug discovery.

Recent Progresses in Conjugation with Bioactive Ligands to Improve the Anticancer Activity of Platinum Compounds

Platinum (Pt) drugs, including cisplatin, are widely used for the treatment of solid tumors. Despite the clinical success, side effects and occurrence of resistance represent major limitations to the use of clinically available Pt drugs. To overcome these problems, a variety of derivatives have been designed and synthetized. Here, we summarize the recent progress in the development of Pt(II) and Pt(IV) complexes with bioactive ligands. The development of Pt(II) and Pt(IV) complexes with targeting molecules, clinically available agents, and other bioactive molecules is an active field of research. Even if none of the reported Pt derivatives has been yet approved for clinical use, many of these compounds exhibit promising anticancer activities with an improved pharmacological profile. Thus, planning hybrid compounds can be considered as a promising approach to improve the available Pt-based anticancer agents and to obtain new molecular tools to deepen the knowledge of cancer progression and drug resistance mechanisms.

Cell-permeable lanthanide-platinum(IV) anti-cancer prodrugs

Platinum compounds are a vital part of our anti-cancer arsenal, and determining the location and speciation of platinum compounds is crucial. We have synthesised a lanthanide complex bearing a salicylic group (Ln = Gd, Eu) which demonstrates excellent cellular accumulation and minimal cytotoxicity. Derivatisation enabled access to bimetallic lanthanide-platinum(ii) and lanthanide-platinum(iv) complexes. Luminescence from the europium-platinum(iv) system was quenched, and reduction to platinum(ii) with ascorbic acid resulted in a "switch-on" luminescence enhancement. We used diffusion-based 1H NMR spectroscopic methods to quantify cellular accumulation. The gadolinium-platinum(ii) and gadolinium-platinum(iv) complexes demonstrated appreciable cytotoxicity. A longer delay following incubation before cytotoxicity was observed for the gadolinium-platinum(iv) compared to the gadolinium-platinum(ii) complex. Functionalisation with octanoate ligands resulted in enhanced cellular accumulation and an even greater latency in cytotoxicity.

Targeting Sphingosine Kinase by ABC294640 against Diffuse Intrinsic Pontine Glioma (DIPG)

As a highly aggressive pediatric brainstem tumor, diffuse intrinsic pontine glioma (DIPG) accounts for 10% to 20% of childhood brain tumors. The survival rate for DIPG remains very low, with a median survival time as less than one year even under radiotherapy, the current standard treatment. Moreover, over than 250 clinical trials have failed when trying to improve the survival compared to radiotherapy. The sphingolipid metabolism and related signaling pathways have been found closely related to cancer cell survival; however, the sphingolipid metabolism targeted therapies have never been investigated in DIPG. In the current study, the anti-DIPG activity of ABC294640, the only first-in-class orally available Sphingosine kinase (SphK) inhibitor was explored. Treatment with ABC294640 significantly repressed DIPG cell growth by inducing intracellular pro-apoptotic ceramides production and cell apoptosis. We also profiled ABC294640-induced changes in gene expression within DIPG cells and identified many new genes tightly controlled by sphingolipid metabolism, such as IFITM1 and KAL1. These genes are required for DIPG cell survival and display clinical relevance in DIPG patients' samples. Together, our findings in this study indicate that targeting sphingolipid metabolism may represent a promising strategy to improve DIPG treatment.