Pin1 protein: a druggable target in high grade serous ovarian cancer

I focused my attention on Pin1 expression and chemical inhibition in HGS-EOC models. First, I confirmed that Pin1 is effectively involved in tumor progression utilizing mouse ovarian surface epithelial cancer cell line (STOSE), which closely recapitulates the characteristics of human HGS-EOC. So, I showed that comparing normal and knock down cells there is a tumor formation only in mice with Pin1 expression and activity. Then I focused my attention in order to develop an efficient Pin1 inhibitor, able to down regulate Pin1 expression in vitro but also in vivo. Starting from the inhibitor developed by Pfizer (Fig.9), which showed a good enzymatic activity in vitro 90, and it\u2019s very specific for the catalytic site of the enzyme, in the last 3 years I worked in order to increase the permeability of this compound.The presence of carboxylate group permits the formation of different H-bond interactions in the proline binding site, interactions necessary for Pin1 catalytic function. Also the benzyl-imidaziole is a donator of hydrogen bonds that stabilize the interaction with Pin1. Despite significant improvements in Pin1 inhibitor affinity, these benzimidazole-based inhibitors failed to show cellular effects (up to 100 \u3bcM) on cancer cells. The authors hypothesized that this was due to poor cell permeability caused by high polarity on the benzimidazole series. The hydrophobic and nonionizable drugs cannot be loaded into liposomes through conventional means. In fact, ionisable hydrophilic drug can be remote loaded inside the liposomes using a transmembrane pH with efficient incorporation The most important example is the Doxil. But a poorly soluble hydrophobic drug is not encorporated into liposomes with the same high efficacy. For this reasons, how reported from Volgestein group, the hydrophobic compound can be actively loaded into liposomes by encapsulating them into modified cyclodextrins.The encapsulation of a poorly soluble drug into an ionizable cyclodextrin (preloading) enhances its water solubility and permits efficient liposomal loading via a pH gradient. In our protocol the Pin1 inhibitor, called compound 8, is preloaded inside modified cyclodextrins, Heptakis 6ammino6deoxy cyclodextrins, and then the complex cyclodextrin-compound 8 (C8) is loaded inside the liposomes via a pH gradient. How reported in the published article, the complex liposomes-cyclodextrin-compound 8 (LC8) is able to down regulate the Pin1 level in vitro, reducing the vitality of cancer cells, and also had activity in vivo, reducing the tumor volume and the Pin1 expression

Virtual screening identifies a PIN1 inhibitor with possible antiovarian cancer effects

Peptidyl-prolyl cis–trans isomerase, NIMA-interacting 1 (PIN1) is a peptidyl-prolyl isomerase that binds phospho-Ser/Thr-Pro motifs in proteins and catalyzes the cis–trans isomerization of proline peptide bonds. PIN1 is overexpressed in several cancers including high-grade serous ovarian cancer. Since few therapies are effective against this cancer, PIN1 could be a therapeutic target but effective PIN1 inhibitors are lacking. To identify molecules with in vivo inhibitory effects on PIN1, we used consensus docking to model existing PIN1-ligand X-ray structures and to screen a chemical database for candidate inhibitors. Ten molecules were selected and tested in cellular assays, leading to the identification of VS10 that bound and inhibited PIN1. VS10 treatment reduced the viability of ovarian cancer cell lines by inducing proteasomal PIN1 degradation, without effects on PIN1 transcription, and also reduced the levels of downstream targets β-catenin, cyclin D1, and pSer473-Akt. VS10 is a selective PIN1 inhibitor that may offer new opportunities for treating PIN1-overexpressing tumors

Enhanced Chemotherapeutic Behavior of Open-Caged DNA@Doxorubicin Nanostructures for Cancer Cells

In cancer therapy, it is imperative to increase the efficacy and reduce side effects of chemotherapeutic drugs. Nanotechnology offers the unique opportunity to overcome these barriers. In particular, in the last few years, DNA nanostructures have gained attention for their biocompatibility, easy customized synthesis and ability to deliver drugs to cancer cells. Here, an open-caged pyramidal DNA@Doxorubicin (Py-Doxo) nanostructure was constructed with 10 DNA sequences of 26\u201328 nucleotides for drug delivery to cancer cells. The synthesized DNA nanostructures are sufficiently stable in biological medium. Py-Doxo exhibited significantly enhanced cytotoxicity of the delivered doxorubicin to breast and liver cancer cells up to twofold compared to free doxorubicin. This study demonstrates the importance of the shape and structure of the designed transporter DNA nanostructures for biomedical applications

Biocompatible tailored zirconia mesoporous nanoparticles with high surface area for theranostic applications

Nanocarriers as theranostic agents are under the spotlight in modern nanomedicine, and mesoporous nanomaterials represent a class of devices of major interest. Zirconia is biocompatible, inert with good mechanical and thermal properties for in vivo biomedical applications. Although a few examples of zirconia nanoparticles have been described, a major limitation was the low surface area, which is fundamental for payload transport. Here, a simple and highly efficient method is described for the synthesis of spherical mesoporous zirconia nanoparticles (MZNs) with a high surface area through a neutral surfactant-assisted sol-gel method. The combination of alkali halides and vacuum extraction allowed stabilization of the shape and size of MZNs and to avoid porous network failure, respectively. In comparison to published synthesis procedures, a high surface area has been obtained. Biological experiments demonstrated that MZNs were biocompatible, cell permeable and degradable providing a proof of concept for theranostic applications. A comparison with the properties of mesoporous silica nanoparticles has also been performed.Nanocarriers as theranostic agents are under the spotlight in modern nanomedicine, and mesoporous nanomaterials represent a class of devices of major interest. Zirconia is biocompatible, inert with good mechanical and thermal properties for in vivo biomedical applications. Although a few examples of zirconia nanoparticles have been described, a major limitation was the low surface area, which is fundamental for payload transport. Here, a simple and highly efficient method is described for the synthesis of spherical mesoporous zirconia nanoparticles (MZNs) with a high surface area through a neutral surfactant-assisted sol-gel method. The combination of alkali halides and vacuum extraction allowed stabilization of the shape and size of MZNs and to avoid porous network failure, respectively. In comparison to published synthesis procedures, a high surface area has been obtained. Biological experiments demonstrated that MZNs were biocompatible, cell permeable and degradable providing a proof of concept for theranostic applications. A comparison with the properties of mesoporous silica nanoparticles has also been performed

Cyclic Ketoximes as Estrogen Receptorβ Selective Agonists

The development of estrogen receptorβ (ERβ)-selective agonists represents a therapeutic strategy against several kinds of cancers, but the high homology between the two receptor subtypes, ERα and ERβ, makes the achievement of this goal very challenging. In the past, we developed salicylaldoxime- and salicylketoxime-based molecules that proved to bind well to ERβ. In this paper, further structural evolution of the salicylketoximes is presented: two of the newly synthesized five-membered cyclic ketoximes bind with nanomolar affinities to ERβ, and they show selectivity for this subtype over ERα. Their agonist character was confirmed by cell-free coactivator recruitment assays, in which we demonstrated the ability of these compounds to form an active complex with ERβ capable of recruiting coactivator proteins; this indicated their efficacy as agonists. Finally, their potency and selectivity for ERβ binding were rationalized by molecular-modeling studies

Virtual screening identifies a PIN1 inhibitor with possible antiovarian cancer effects

Peptidyl-prolyl cis–trans isomerase, NIMA-interacting 1 (PIN1) is a peptidyl-prolyl isomerase that binds phospho-Ser/Thr-Pro motifs in proteins and catalyzes the cis–trans isomerization of proline peptide bonds. PIN1 is overexpressed in several cancers including high-grade serous ovarian cancer. Since few therapies are effective against this cancer, PIN1 could be a therapeutic target but effective PIN1 inhibitors are lacking. To identify molecules with in vivo inhibitory effects on PIN1, we used consensus docking to model existing PIN1-ligand X-ray structures and to screen a chemical database for candidate inhibitors. Ten molecules were selected and tested in cellular assays, leading to the identification of VS10 that bound and inhibited PIN1. VS10 treatment reduced the viability of ovarian cancer cell lines by inducing proteasomal PIN1 degradation, without effects on PIN1 transcription, and also reduced the levels of downstream targets β-catenin, cyclin D1, and pSer473-Akt. VS10 is a selective PIN1 inhibitor that may offer new opportunities for treating PIN1-overexpressing tumors

Liposomal delivery of a Pin1 inhibitor complexed with cyclodextrins as new therapy for high-grade serous ovarian cancer.

Pin1, a prolyl isomerase that sustains tumor progression, is overexpressed in different types of malignancies. Functional inactivation of Pin1 restrains tumor growth and leaves normal cells unaffected making it an ideal pharmaceutical target. Although many studies on Pin1 have focused on malignancies that are influenced by sex hormones, studies in ovarian cancer have lagged behind. Here, we show that Pin1 is an important therapeutic target in high-grade serous epithelial ovarian cancer. Knock down of Pin1 in ovarian cancer cell lines induces apoptosis and restrains tumor growth in a syngeneic mouse model. Since specific and non-covalent Pin1 inhibitors are still limited, the first liposomal formulation of a Pin1 inhibitor was designed. The drug was efficiently encapsulated in modified cyclodextrins and remotely loaded into pegylated liposomes. This liposomal formulation accumulates preferentially in the tumor and has a desirable pharmacokinetic profile. The liposomal inhibitor was able to alter Pin1 cancer driving-pathways trough the induction of proteasome-dependent degradation of Pin1 and was found to be effective in curbing ovarian tumor growth in vivo

Strategies to optimize siRNA delivery to hepatocellular carcinoma cells

Introduction: hepatocellular carcinoma (hcc) is the predominant form of primary liver cancer and the second leading cause of cancer-associated mortality worldwide. available therapies for hcc have limited efficacy due to often late diagnosis and the general resistance of hcc to anti-cancer agents; therefore, the development of novel therapeutics is urgently required. small-interfering rna (sirna) molecules are short, double-stranded rnas that specifically recognize and bind the mrna of a target gene to inhibit gene expression. despite the great therapeutic potential of sirnas towards many human tumors including hcc, their use is limited by suboptimal delivery. Areas covered: In this review, we outline the current data regarding the therapeutic potential of siRNAs in HCC and describe the development of effective siRNA delivery systems. We detail the key problems associated with siRNA delivery and discuss the possible solutions. Finally, we provide examples of the various siRNA delivery strategies that have been employed in animal models of HCC and in human patients enrolled in clinical trials. Expert opinion: Despite the existing difficulties in siRNA delivery for HCC, the increasing scientific attention and breakthrough studies in this field is facilitating the design of novel and efficient technical solutions that may soon find practical applications