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Generally, Hsp27 can be used as a suitable carrier in DNA vaccine design against HIV-1 infections (Fig. 5, Ref. 28).

IntroductionThe application of nanoparticles (NPs) in medicine and biology has received great interest due to their novel features. However, their adverse effects on the biological system are not well understood.Materials and methodsThis study aims to evaluate the effect of cerium oxide nanoparticles (CNPs) on conformational changes of human hemoglobin (HHb) and lymphocytes by different spectroscopic (intrinsic and synchronous fluorescence spectroscopy and far and near circular dichroism [CD] spectroscopy), docking and cellular (MTT and flow cytometry) investigations.Results and discussionTransmission electron microscopy (TEM) showed that CNP diameter is ~30 nm. The infrared spectrum demonstrated a strong band around 783 cm−1 corresponding to the CNP stretching bond. Fluorescence data revealed that the CNP is able to quench the intrinsic fluorescence of HHb through both dynamic and static quenching mechanisms. The binding constant (Kb), number of binding sites (n), and thermodynamic parameters over three different temperatures indicated that hydrophobic interactions might play a considerable role in the interaction of CNPs with HHb. Synchronous fluorescence spectroscopy indicated that microenvironmental changes around Trp and Tyr residues remain almost unchanged. CD studies displayed that the regular secondary structure of HHb had no significant changes; however, the quaternary structure of protein is subjected to marginal structural changes. Docking studies showed the larger CNP cluster is more oriented toward experimental data, compared with smaller counterparts. Cellular assays revealed that CNP, at high concentrations (>50 µg/mL), initiated an antiproliferative response through apoptosis induction on lymphocytes.ConclusionThe findings may exhibit that, although CNPs did not significantly perturb the native conformation of HHb, they can stimulate some cellular adverse effects at high concentrations that may limit the medicinal and biological application of CNPs. In other words, CNP application in biological systems should be done at low concentrations.

Background: Studies on the fractional extracts of Galium verum L. have confirmed their cytotoxicity and anticancer effects on various cancer cell lines. Objectives: The present study aimed to investigate the cytotoxic effects of Galium verum extracts on liver and colon cancer cell lines. Methods: Colon cancer (HT29) and liver (HepG2) cell lines were randomly divided into the test and control groups and exposed to 100, 50, 25, 12.5, 6.25, and 3.125 µg/mL of the extract. MTT assay was used to evaluate the viability of the cells, and the groups were compared in the GraphPad Prism software using Tukey’s post-hoc test. Results: The chloroform fractional extract of Galium verum exerted cytotoxic effects on HT29 at the concentrations of 100 and 50 µg/mL and increased the cell viability of HepG2 cancer cells. On the other hand, the fraction of petroleum ether had cytotoxic effects on HT29 at all the determined concentrations, as well as on HepG2 at the concentration of 3.125 µg/mL. In addition, the treatment of HT29 with various concentrations of the petroleum ether fractional extract and HepG2 treatment with the same extract at the concentration of 3.125 µg/mL significantly decreased cell viability compared to the control group. The IC50 concentration was determined at > 100 µg/mL. Conclusions: According to the results, the fractional extract of petroleum ether had cytotoxic effects on HT29 cancer cells at all the concentrations, while it affected HepG2 cancer cells only at the concentration of 3.125 µg/mL.