Metal-derived platinum complexes are widely used to treat solid tumors. However, systemic toxicity and tumor resistance to these drugs encourage further research into similarly effective compounds. Among others, organotin compounds have been shown to inhibit cell growth and induce cell death and autophagy. Nevertheless, the impact of the ligand structure and mechanisms involved in the toxicity of organotin compounds have not been clarified. In the present study, the biological activities of commercially available bis(tributyltin) oxide and tributyltin chloride, in comparison to those of specially synthesized tributyltin trifluoroacetate (TBT-OCOCF₃) and of cisplatin, were assessed using cells with different levels of tumorigenicity. The results show that tributyltins were more cytotoxic than cisplatin in all the tested cell lines. NMR revealed that this was not related to the interaction with DNA but to the inhibition of glucose uptake into the cells. Moreover, highly tumorigenic cells were less susceptible than nontumorigenic cells to the nonunique pattern of death induced by TBT-OCOCF₃. Nevertheless, tumorigenic cells became sensitive when cotreated with wortmannin and TBT-OCOCF₃, although no concomitant induction of autophagy by the compound was detected. Thus, TBT-OCOCF₃ might be the prototype of a family of potential anticancer agents.

Based on previous experience in our laboratory, we developed a real-time reverse transcriptase (RT) quantitative PCR (RT-qPCR) assay for the assessment of very low levels of HIV-1 RT activity. The RNA, acting as a template for reverse transcription into cDNA by HIV-1 RT, consisted of a synthetic RNA ad hoc generated by in vitro transcription and included a coding sequence for HSV-1 gD (gD-RNA-synt). Different conditions of variables involved in the RT-qPCR reaction, notably different amounts of gD-RNA-synt, different mixes of the reaction buffer, and different dNTP concentrations, were tested to optimize the assay. The results indicated that the gD-RNA-synt-based RT assay, in its optimized formulation, could detect a specific cDNA reverse transcription even in the presence of 1 × 10⁻⁹ U of HIV RT. This achievement greatly improved the sensitivity of the assay over previous versions. In summary, this constructed RT-qPCR assay may be considered a promising tool for providing accurate information on very low HIV-1 RT activity.

Testing HIV-1 RNA in plasma by PCR is universally accepted as the ultimate standard to confirm diagnosis of HIV-1 infection and to monitor viral load in patients under treatment. However, in some cases, this assay could either underestimate or overestimate the replication capacity of a circulating or latent virus. In the present study, we performed the assessment of evaluating the HIV-1 reverse transcriptase (RT) activity by means of a new assay for the functional screening of the status of HIV-1 patients. To this purpose, we utilized, for the first time on blood samples, an adapted version of a real-time RT quantitative PCR assay, utilized to evaluate the HIV-1-RT inhibitory activity of compounds. The study analyzed blood samples from 28 HIV-1-infected patients, exhibiting a wide range of viremia and immunological values. Results demonstrated that plasma HIV-1 RT levels, expressed as cycle threshold values obtained with the assay under appraisal, were inversely and highly significantly correlated with the plasma HIV-1-RNA levels of the patients. Thus, an HIV-1 RT quantitative PCR assay was created which we describe in this study, and it may be considered as a promising basis for an additional tool capable of furnishing information on the functional virological status of HIV-1-infected patients.

3D cell systems for in vitro experimental studies are able to mimic the in vivo efficacy of drugs before they are tested on animals. However, many studies are still needed in order to mimic the physiological environment with 3D cell-growth systems. The mechano-physical properties of the microenvironment are relevant for the invasiveness of cancer cells and for their drug resistance. In this study, 3D tumoroids of human oral squamous cell carcinoma (OSCC) CAL27 cells of different stiffnesses were produced using a tunable PEG–silk fibroin hydrogel (PSF), and the antitumor activity of the peptide CIGB300, an anticancer therapeutic peptide, with respect to these 3D tumoroid models was assessed. Furthermore, spectroscopic studies on the CIGB300 peptide are reported regarding its structure, stability, aggregation and diffusion properties. For the first time, the diffusion of the peptide CIGB300 in tunable silk fibroin hydrogels of different stiffnesses is investigated over time via fluorescence spectroscopy as a potential tool in drug-screening using hydrogel-based 3D tumoroids.

Among the metal-derived complexes, recently, tin derivatives have been investigated as promising anti-cancer drug candidates. Our previous study showed that the tin-based compound Bu₃SnOCOCF₃ (TBT) exerts cytotoxic activity on solid tumor cell lines. In the present study, the effects of TBT were evaluated in vitro on HTLV-1-infected human lymphocytic cell lines at different stages of viral transformation, consisting of IL-2-dependent (PB2/IL-2) and IL-2-independent (PB2/NO-IL-2) cells, generated in our laboratory by HTLV-1 in vitro infection of lymphocytes from the same donor, and the C91/PL cell line established by co-cultivation with T cells from a patient with HTLV-1-positive leukemia. TBT induced a reliable and reproducible dose-dependent inhibition of metabolic activity and viability in the HTLV-1-infected cells. The effect was cell-type-dependent, with C91/PL cells being quite resistant. An investigation into the cytotoxic effects induced by TBT in HTLV-1-infected cells and data on caspase inhibitors/caspase activation indicated that apoptotic cell death was involved, but also that the possible involvement of other forms of cell death could not be excluded. Taken together, the results show for the first time that the tin-based compound, although not devoid of a certain cytotoxicity toward uninfected cells, can induce typical and potent effects on HTLV-1-infected cells.

3D cell systems for in vitro experimental studies are able to mimic the in vivo efficacy of drugs, before testing on animals, however many studies are still needed for mimicking the physiological environment with 3D cell growth systems. The mechano-physical properties of the microenvironment are relevant for the invasiveness of cancer cells and also for their drug resistance. 3D tumoroids of human oral squamous cell carcinoma (OSCC) CAL27 cells of different stiffness are here produced using a tunable PEG-silk fibroin hydrogel (PSF) and the anti-tumor activity of the CIGB300 peptide, an anticancer therapeutic peptide, on these 3D tumoroids models is assessed. Moreover, spectroscopical studies on CIGB300 peptide are here also reported for analyzing its structure, stability, aggregation and diffusion properties. For the first time, the CIGB300 peptide diffusion in tunable silk fibroin hydrogels of different stiffness is investigated over-time by fluorescence spectroscopy as potential tool in drug-screening using hydrogel-based 3D tumoroids.