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Edible insects are generally reared on agricultural product-based diets. These feeding substrates may contain pesticides or toxins that are derived from field practices for plant growth and defence and that may represent a health risk to insect consumers. The present study investigated Tenebrio molitor capability to uptake from contaminated substrates three chemical compounds that are employed in agricultural practices: the insecticide deltamethrin (DELTA), the fungicide tebuconazole (TEB) and the plant growth regulator chlormequat chloride (CCC), all with different properties of lipophilicity and potentially harmful for human and animal health. Newly optimised and validated LC-MS/MS methods have been used for the quantification of pesticide residues in larvae samples. Analysis showed that DELTA and TEB are retained by larvae, even after 24 h of fasting, due to their lipophilicity. Larvae fasting period allowed the elimination of 47% of DELTA residues and 78% of TEB ones. Diversely, CCC, the most hydrophilic chemical compound, was completely eliminated after the fasting. The toxicity of pesticides to larvae has been also investigated. The highest mortality of T. molitor larvae (close to 50%) was recorded for the insecticide DELTA, at the dose of 20 mg/kg and for CCC (15%) at the concentration of 4 mg/kg. The safety of insects as food and feed represents an important section in the field of the control of food of animal origin and animal health. Nevertheless, to date, this aspect is not yet completely determined due to the lack of scientific data in this area. By assessing the accumulation rate of some chemicals in reared insects and by evaluating the toxic effects that chemicals may have on larvae, this study could contribute to filling this gap.

Si113, a pyrazolo[3,4-d]pyrimidine derivative, gained more attention as an anticancer agent due to its potent anticancer activity on both in vitro and in vivo hepatocellular carcinomas (HCC) and ovarian carcinoma models. But the drawback is the low water solubility which prevents its further development. In this context, we successfully overcame this limitation by synthesizing two novel prodrugs introducing the amino acid sequence D-Ala-Leu-Lys (TP). Moreover, TP sequence has a high affinity with plasmin, a protease recognized as overexpressed in many solid cancers, including HCC and ovarian carcinoma. The prodrugs were synthesized and fully characterized in terms of in vitro ADME properties, plasma stability and plasmin-induced release of the parent drug. The inhibitory activity against Sgk1 was evaluated and in vitro growth inhibition was evaluated on ovarian carcinoma and HCC cell lines in the presence and absence of human plasmin. In vivo pharmacokinetic properties and preliminary tissue distribution confirmed a better profile highlighting the importance of the prodrug approach. Finally, the prodrug antitumor efficacy was evaluated in an HCC xenografted murine model, where a significant reduction (around 90%) in tumor growth was observed. Treatment with ProSi113-TP in combination with paclitaxel in a paclitaxel-resistant ovarian carcinoma xenografted murine model, resulted in an impressive reduction of tumor volume greater than 95%. Our results revealed a promising activity of Si113 prodrugs and pave the way for their further development against resistant cancer.

[Image: see text] Hepatocellular carcinoma (HCC) is one of the most fatal cancer types worldwide. HCC cells were proved to overexpress c-Src and Sgk1, a tyrosine and a serine-threonine kinase, respectively, whose role is crucial for the development and progression of the tumor. Pyrazolo[3,4-d]pyrimidine derivatives are a class of tyrosine kinase inhibitors that have shown good activity against HepG2. HCC cells were also proved to overexpress plasmin, which is localized on the cell surface bound to its receptors. In this study, a tripeptide with sequence d-Ala-Phe-Lys, which binds a specific reactive site of plasmin, was synthesized and characterized. This tripeptide was used to decorate liposomes encapsulating three selected pyrazolo[3,4-d]pyrimidines. Liposomes bearing tripeptide have been characterized, not showing remarkable differences with respect to the corresponding tripeptide-free liposomes. In vitro HepG2 cell uptake profiles and cytotoxicities showed that the presence of the tripeptide on the liposomal membrane surface improves the cell-penetrating ability of liposomes and increases the activity of two of the three tested compounds.

Pyrazolo[3,4-d]pyrimidine derivatives 1–5, active as c-Src inhibitors, have been selected to be formulated as drug-loaded human serum albumin (HSA) nanoparticles, with the aim of improving their solubility and pharmacokinetic properties. The present study includes the optimization of a desolvation method-based procedure for preparing HSA nanoparticles. First, characterization by HPLC-MS and Dynamic Light Scattering (DLS) showed a good entrapment efficacy, a controllable particle size (between 100 and 200 nm) and an optimal stability over time, confirmed by an in vitro drug release assay. Then, 1–4 and the corresponding NPs were tested for their antiproliferative activity against neuroblastoma SH-SY5Y cell line. Notably, 3-NPs and 4-NPs were identified as the most promising formulation showing a profitable balance of stability, small size and a similar activity compared to the free drugs in cell-based assays. In addition, albumin formulations increase the solubility of pyrazolo[3,4-d]pyrimidine avoiding the use of DMSO as solubilizing agent.

The aim of this study was the preclinical development of a set of pyrazolo[3,4-d]pyrimidine structure-based small molecules ATP-competitive SRC inhibitors for the therapy of glioblastoma (GBM), a rare but extremely aggressive and infiltrative glial tumor with a very limited response to therapies. Ongoing preclinical and clinical studies of tyrosine kinase inhibitors (TKIs) for the therapy of GBM identified SRC family inhibitors as a significant and effective therapeutic strategy (i.e. dasatinib, bosutinib, PP2). In vitro Screening: From the wide in-house synthesized pyrazolo[3,4-d]pyrimidines’ library, nine compounds have been selected to be formulated and tested in in vitro and in vivo GBM pharmacological models. Among all the examined formulations, the prodrug approach has been applied to the candidate drugs, introducing the N-methylpiperazine moiety by a carbamate-based linker (in vivo enzymatically hydrolysable). Drugs and corresponding prodrugs have been screened on the basis of their SRC Ki and in vitro ADME properties. GBM U87 cell assays showed IC50 in the sub-micromolar range (1.5 - 15.0 µM) for almost all compounds and improved cellular uptake of the prodrugs in respect to the corresponding drugs. PK and Toxicity: After that, the most promising compound has been selected for further in vitro assays and in vivo tests. In vivo pharmacokinetics and pharmacodynamics have been evaluated for the compound by various formulations, routes of administration and dosages. In all cases investigated, the compound has been proved to reach the brain. As expected, prodrug plasmatic MRT and AUC confirmed the realization of an extended release formulation that allows a higher overall exposure to the drug. In addition, considering an estimated oral bioavailability of 40.4% and a 11-fold higher Cmax in respect to i.v. and i.p. administration, the oral route can be identified as the most advantageous for the compound for GBM treatment. Moreover, an acute toxicity study revealed that the LD50 for i.v. toxicity is more than 100 mg/kg with a good tolerability. In vivo Efficacy Tests: The selected compound and its prodrug were orally administered in GBM orthotopic mouse model and results indicated a median survival rate 10% greater for prodrug-treated mice in respect to drug-treated mice and 35% greater in respect to control group. The combination effect of the compound and radiotherapy was also investigated in subcutaneous U87 xenografted mice model and resulted in a reduction of the tumor growth close to 80% in respect to the control growth. Conclusions: Taking into account all the data collected regarding their pharmacological properties, pyrazolo[3,4-d]pyrimidines SRC inhibitors class of compounds deserve further investigation to show its potential to become a new therapy for GBM. Citation Format: Arianna Mancini, Anna Lucia Fallacara, Claudio Zamperini, Giulia Iovenitti, Alessio Molinari, Enrico Rango, Adriano Angelucci, Silvia Schenone, Maurizio Botta. Preclinical development of novel pyrazolo[3,4-d]pyrimidines structure-based TKIs for the treatment of glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2201.