Molecular engineering of a spheroid-penetrating phage nanovector for photodynamic treatment of colon cancer cells.

Photodynamic therapy (PDT) represents an emerging strategy to treat various malignancies, including colorectal cancer (CC), the third most common cancer type. This work presents an engineered M13 phage retargeted towards CC cells through pentavalent display of a disulfide-constrained peptide nonamer. The M13CC nanovector was conjugated with the photosensitizer Rose Bengal (RB), and the photodynamic anticancer effects of the resulting M13CC-RB bioconjugate were investigated on CC cells. We show that upon irradiation M13CC-RB is able to impair CC cell viability, and that this effect depends on i) photosensitizer concentration and ii) targeting efficiency towards CC cell lines, proving the specificity of the vector compared to unmodified M13 phage. We also demonstrate that M13CC-RB enhances generation and intracellular accumulation of reactive oxygen species (ROS) triggering CC cell death. To further investigate the anticancer potential of M13CC-RB, we performed PDT experiments on 3D CC spheroids, proving, for the first time, the ability of engineered M13 phage conjugates to deeply penetrate multicellular spheroids. Moreover, significant photodynamic effects, including spheroid disruption and cytotoxicity, were readily triggered at picomolar concentrations of the phage vector. Taken together, our results promote engineered M13 phages as promising nanovector platform for targeted photosensitization, paving the way to novel adjuvant approaches to fight CC malignancies.

Computer-aided identification, synthesis, and biological evaluation of DNA polymerase η inhibitors for the treatment of cancer.

In cancer cells, Pol η allows DNA replication and cell proliferation even in the presence of chemotherapeutic drug-induced damages, like in the case of platinum-containing drugs. Inhibition of Pol η thus represents a promising strategy to overcome drug resistance and preserve the effectiveness of chemotherapeutic drugs. Here, we report the discovery of a novel class of Pol ƞ inhibitors, with 35 active close analogs. Compound 21 (ARN24964) stands out as the best inhibitor, with an IC50 value of 14.7 µM against Pol η and a good antiproliferative activity when used in combination with cisplatin - with a synergistic effect in three different cancer cell lines (A375, A549, OVCAR3). Moreover, it is characterized by a favorable drug-like profile in terms of its aqueous kinetic solubility, plasma and metabolic stability. Thus, ARN24964 is a promising compound for further structure-based drug design efforts toward developing drugs to solve or limit the issue of drug resistance to platinum-containing drugs in cancer patients.

Design, synthesis, docking, and biochemical characterization of non-nucleoside SARS-CoV-2 RdRp inhibitors.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a worldwide pandemic. The identification of effective antiviral drugs remains an urgent medical need. In this context, here we report 17 new 1,4-benzopyrone derivatives, which have been designed, synthesized, and characterized for their ability to block the RNA-dependent RNA polymerase (RdRp) enzyme, a promising target for antiviral drug discovery. This compound series represents a good starting point for developing non-nucleoside inhibitors of RdRp. Compounds 4, 5, and 8 were the most promising drug-like candidates with good potency in inhibiting RdRp, improved in vitro pharmacokinetics compared to the initial hits, and no cytotoxicity effects on normal cell (HEK-293). Compound 8 (ARN25592) stands out as the most promising inhibitor. Our results indicate that this new chemical class of 1,4-benzopyrone derivatives deserves further exploration towards novel and potent antiviral drugs for the treatment of SARS-CoV-2 and potentially other viruses.

Orthogonal nanoarchitectonics of M13 phage for receptor targeted anticancer photodynamic therapy.

Photodynamic therapy (PDT) represents a promising therapeutic modality for cancer. Here we used an orthogonal nanoarchitectonics approach (genetic/chemical) to engineer M13 bacteriophages as targeted vectors for efficient photodynamic killing of cancer cells. M13 was genetically refactored to display on the phage tip a peptide (SYPIPDT) able to bind the epidermal growth factor receptor (EGFR). The refactored M13EGFR phages demonstrated EGFR-targeted tropism and were internalized by A431 cancer cells, that overexpress EGFR. Using an orthogonal approach to the genetic display, M13EGFR phages were then chemically modified, conjugating hundreds of Rose Bengal (RB) photosensitizing molecules on the capsid surface, without affecting the selective recognition of the SYPIPDT peptides. Upon internalization, the M13EGFR-RB derivatives generated intracellularly reactive oxygen species, activated by an ultralow intensity white light irradiation. The killing activity of cancer cells is observed at picomolar concentrations of the M13EGFR phage.

Design, Synthesis, Dynamic Docking, Biochemical Characterization, and in Vivo Pharmacokinetics Studies of Novel Topoisomerase II Poisons with Promising Antiproliferative Activity.

We previously reported a first set of hybrid topoisomerase II (topoII) poisons whose chemical core merges key pharmacophoric elements of etoposide and merbarone, which are two well-known topoII blockers. Here, we report on the expansion of this hybrid molecular scaffold and present 16 more hybrid derivatives that have been designed, synthesized, and characterized for their ability to block topoII and for their overall drug-like profile. Some of these compounds act as topoII poison and exhibit good solubility, metabolic (microsomal) stability, and promising cytotoxicity in three cancer cell lines (DU145, HeLa, A549). Compound 3f (ARN24139) is the most promising drug-like candidate, with a good pharmacokinetics profile in vivo. Our results indicate that this hybrid new chemical class of topoII poisons deserves further exploration and that 3f is a favorable lead candidate as a topoII poison, meriting future studies to test its efficacy in in vivo tumor models.