Probing the DNA Reactivity and the Anticancer Properties of a Novel Tubercidin-Pt(II) Complex

Red Blood Cell Membrane-Camouflaged Polydopamine and Bioactive Glass Composite Nanoformulation for Combined Chemo/Chemodynamic/Photothermal Therapy

Combinations of different therapeutic strategies, including chemotherapy (CT), chemodynamic therapy (CDT), and photothermal therapy (PTT), are needed to effectively address evolving drug resistance and the adverse effects of traditional cancer treatment. Herein, a camouflage composite nanoformulation (TCBG@PR), an antitumor agent (tubercidin, Tub) loaded into Cu-doped bioactive glasses (CBGs) and subsequently camouflaged by polydopamine (PDA), and red blood cell membranes (RBCm), was successfully constructed for targeted and synergetic antitumor therapies by combining CT of Tub, CDT of doped copper ions, and PTT of PDA. In addition, the TCBG@PRs composite nanoformulation was camouflaged with a red blood cell membrane (RBCm) to improve biocompatibility, longer blood retention times, and excellent cellular uptake properties. It integrated with long circulation and multimodal synergistic treatment (CT, CDT, and PTT) with the benefit of RBCms to avoid immune clearance for efficient targeted delivery to tumor locations, producing an "all-in-one" nanoplatform. In vivo results showed that the TCBG@PRs composite nanoformulation prolonged blood circulation and improved tumor accumulation. The combination of CT, CDT, and PTT therapies enhanced the antitumor therapeutic activity, and light-triggered drug release reduced systematic toxicity and increased synergistic antitumor effects.

Platinum-Nucleos(t)ide Compounds as Possible Antimetabolites for Antitumor/Antiviral Therapy: Properties and Perspectives

Nucleoside analogues (NAs) are a family of compounds which include a variety of purine and pyrimidine derivatives, widely used as anticancer and antiviral agents. For their ability to compete with physiological nucleosides, NAs act as antimetabolites exerting their activity by interfering with the synthesis of nucleic acids. Much progress in the comprehension of their molecular mechanisms has been made, including providing new strategies for potentiating anticancer/antiviral activity. Among these strategies, new platinum-NAs showing a good potential to improve the therapeutic indices of NAs have been synthesized and studied. This short review aims to describe the properties and future perspectives of platinum-NAs, proposing these complexes as a new class of antimetabolites.

State of art in the chemistry of nucleoside-based Pt(II) complexes

After the fortuitous discovery of the anticancer properties of cisplatin, many Pt(II) complexes have been synthesized, to obtain less toxic leads which could overcome the resistance phenomena. Given the importance of nucleosides and nucleotides as antimetabolites, studying their coordinating properties towards Pt(II) ions is challenging for bioorganic and medicinal chemistry. This review aims to describe the results achieved so far in the aforementioned field, paying particular attention to the synthetic aspects, the chemical-physical characterization, and the biological activities of the nucleoside-based Pt(II) complexes.

Probing the Ca2+ mobilizing properties on primary cortical neurons of a new stable cADPR mimic

Cyclic adenosine diphosphate ribose (cADPR) is a second messenger involved in the Ca²⁺ homeostasis. Its chemical instability prompted researchers to tune point by point its structure, obtaining stable analogues featuring interesting biological properties. One of the most challenging derivatives is the cyclic inosine diphosphate ribose (cIDPR), in which the hypoxanthine isosterically replaces the adenine. As our research focuses on the synthesis of N1 substituted inosines, in the last few years we have produced new flexible cIDPR analogues, where the northern ribose has been replaced by alkyl chains. Interestingly, some of them mobilized Ca²⁺ ions in PC12 cells. To extend our SAR studies, herein we report on the synthesis of a new stable cIDPR derivative which contains the 2″S,3″R dihydroxypentyl chain instead of the northern ribose. Interestingly, the new cyclic derivative and its open precursor induced an increase in intracellular calcium concentration ([Ca²⁺]_i) with the same efficacy of the endogenous cADPR in rat primary cortical neurons.

Synthesis, Antiproliferative Activity, and DNA Binding Studies of Nucleoamino Acid-Containing Pt(II) Complexes

We here report our studies on the reaction with the platinum(II) ion of a nucleoamino acid constituted by the l-2,3-diaminopropanoic acid linked to the thymine nucleobase through a methylenecarbonyl linker. The obtained new platinum complexes, characterized by spectroscopic and mass spectrometric techniques, were envisaged to exploit synergistic effects due to the presence of both the platinum center and the nucleoamino acid moiety. The latter can be potentially useful to protect the complexes from early deactivation, as well as to facilitate their cell internalization. The biological activity of the complexes in terms of antiproliferative effects was evaluated in vitro on different cancer cell lines and healthy cells, showing the best results on human cervical adenocarcinoma (HeLa) cells along with good selectivity for cancer over normal cells. In contrast, the metal-free nucleoamino acid did not show any cytotoxicity on both normal and cancer cell lines. Finally, the ability of the novel Pt(II) complexes to bind various DNA model systems was investigated by circular dichroism (CD) spectroscopy and polyacrylamide gel electrophoresis analyses proving that the newly obtained compounds can potentially target DNA, similarly to other well-known anticancer Pt complexes, with a peculiar G-quadruplex vs. duplex selectivity.