## 3 Results
With the exception of Cas-4, the expression of pro-apoptotic genes generally was not influenced by the incubation of mouse fibroblasts (L-929) with SeNrs or SeNPs. The expression level of the Cas-4 gene increased after pre-incubation with 5 and 10 \(\upmu\)g/mL SeNPs (Figure 6B). The PCR analysis results correlate well with the activation of apoptosis under the selenium nanostructures' influence on human glioblastoma A-172 cells. The contribution to the activation of the cell death can be made by the endoplasmic reticulum stress (ER-stress). Analysis of the gene's expression encoding ER-stress proteins in A-172 cells showed an expression increase (Figure 7). Thus, the treatment of glioblastoma cells with 10 \(\upmu\)g/mL selenium nanoparticles caused the expression of the transcription factor ATF-4 to rise significantly. That may indicate PERK signaling pathway UPR activation. Moreover, when these cells are exposed to SeNPs at 5 and 10 \(\upmu\)g/mL concentrations, the expression of the spliced form of the transcription factor XBP1 is also increased by approximately two times (Figure 7A), which can serve as evidence of the activation of the IRE1\(\alpha\) signaling pathway UPR. An increase in the mRNA expression of these ER-stress markers is also observed after \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**24 h Pre-Incubation**} & \multicolumn{4}{c}{**48 h Pre-Incubation**} \\ \cline{2-9}  & **Control** & **1 \(\upmu\)g/mL** & **5 \(\upmu\)g/mL** & **10 \(\upmu\)g/mL** & **Control** & **1 \(\upmu\)g/mL** & **5 \(\upmu\)g/mL** & **10 \(\upmu\)g/mL** \\ \hline Viable & 100\% & 100\% & 98\% & 94\% & 100\% & 93\% & 81\% & 51\% \\ \hline Early apoptotic & 0\% & 0\% & 2\% & 6\% & 0\% & 7\% & 11\% & 28\% \\ \hline Apoptotic & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% & 8\% & 16\% \\ \hline Necrosis & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% & 5\% \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Effect of different SeNPs concentrations on the survival of L-929 mouse fibroblast cells after 24 and 48 h of exposure. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**24 h Pre-Incubation**} & \multicolumn{4}{c}{**48 h Pre-Incubation**} \\ \cline{2-9}  & **Control** & **1 \(\upmu\)g/mL** & **5 \(\upmu\)g/mL** & **10 \(\upmu\)g/mL** & **Control** & **1 \(\upmu\)g/mL** & **5 \(\upmu\)g/mL** & **10 \(\upmu\)g/mL** \\ \hline Viable & 100\% & 89\% & 94\% & 96\% & 100\% & 91\% & 89\% & 86\% \\ \hline Early apoptotic & 0\% & 11\% & 6\% & 4\% & 0\% & 9\% & 11\% & 14\% \\ \hline Apoptotic & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% \\ \hline Necrosis & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Effect of different SeNrs concentrations on the survival of L-929 mouse fibroblast cells after 24 and 48 h of exposure. 24 h of A-172 cell treatment with 5 \(\upmu\)g/mL SeNrs. These data, as well as the similarity of mRNA patterns of expression of most pro-apoptotic genes, most likely indicate the same molecular mechanisms activated by both nanoselenium composites. However, it should be noted that their cytotoxic effect extends directly to the A-172 cancer cell line, but not to the L-929 fibroblast cells (Figure 7B). Figure 6: The patterns of expression of genes, which encode pro-apoptotic proteins in A-172 (**A**) and L-929 (**B**) cells after 24-h pre-incubation with various (1, 5, 10 \(\upmu\)g/mL) selenium nanorods (SeNrs) or selenium nanoparticles (SeNPs) concentrations. The gene expression level in control cells was taken as 1. \(n\) = 3. Figure 7: The patterns of expression of genes encoding ER-stress proteins, which are involved in activation of apoptosis in A-172 (**A**) and L-929 (**B**) cells after 24-h incubation with different concentrations (1, 5, 10 \(\upmu\)g/mL) of selenium nanorods (SeNrs) or selenium nanoparticles (SeNPs). The gene expression level was taken as 1 in control cells. \(n\) = 3.