The Different Temozolomide Effects on Tumorigenesis Mechanisms of Pediatric Glioblastoma PBT24 and SF8628 Cell Tumor in CAM Model and on Cells In Vitro

Abstract

It is necessary to elucidate the individual effects of temozolomide (TMZ) on carcinogenesis and tumor resistance to chemotherapy mechanisms. The study aimed to investigate the TMZ 50 and 100 μM dose effect difference between PBT24 and SF8628 cell line high-grade pediatric glioblastoma (phGBM) xenografts in a chicken chorioallantoic membrane (CAM) model, on PCNA and EZH2 immunohistochemical expression in the tumor and on the expression of NKCC1, KCC2, E- and N-cadherin genes in TMZ-treated and control cell groups in vitro. TMZ at a 100 μg dose reduced the incidence of PBT24 xenograft invasion into the CAM, CAM thickening and the number of blood vessels in the CAM (p < 0.05), but did not affect the SF8628 tumor in the CAM model. The TMZ impact on PBT24 and SF8628 tumor PCNA expression was similarly significantly effective but did not alter EZH2 expression in the studied tumors. The TMZ at 50 μM caused significantly increased RNA expression of the NKCC1 gene in both studied cell types compared with controls (p < 0.05). The expression of the KCC2 gene was increased in PBT24 TMZ-treated cells (p < 0.05), and no TMZ effect was found in SF8628-treated cells. The study supports the suggestion that individual sensitivity to TMZ should be assessed when starting treatment.

The Comparative Experimental Study of Sodium and Magnesium Dichloroacetate Effects on Pediatric PBT24 and SF8628 Cell Glioblastoma Tumors Using a Chicken Embryo Chorioallantoic Membrane Model and on Cells In Vitro

“…Recently the different temozolomide and valproic acid effects on tumorigenesis mechanisms have been reported, such as their effect on tumor growth, the histological expression of PCNA and EZH2 in tumor cells, Na-K-2Cl, K-Cl, and SLC5A8 co-transporter gene expression in pediatric glioblastoma PBT24 and SF8628 cell tumors on chick embryo chorioallantoic membranes (CAM) and on corresponding cells in vitro, highlighting the importance of studies on efficacy in the context of individualized anticancer therapy [ 37 , 38 ]. This study’s novelty lies in the differential effect of the active substance DCA‘s anions on PBT24 and SF8628 tumors on the CAM and the cells in vitro, comparing the differences in the impact of the studied NaDCA and MgDCA salts.…”

“…Such data suggest that EZH2 inhibitors in pediatric glioblastoma treatment should be investigated further [ 58 ]. We recently reported that TMZ did not alter EZH2 expression but significantly reduced PCNA expression in PBT24 and SF8628 tumors on CAM [ 37 ]. In the SF8628 control tumor, the correlation between EZH2 and p53 was solid and significant, while in the PBT24 control tumor, the correlation was weak and insignificant.…”

“…The treatment with the studied DCA preparations did not effect the expression of SLC12A2 , SLC12A5 , and SLC5A8 in the PBT24 and SF8628 cells. The DCA did not increase SLC12A2 expression, suggesting that it could be used in combination with other anticancer agents, such as temozolomide, which increases SLC12A2 expression in phGBM cells [ 37 ]. SLC12A5 expression in the SF8628 control and DCA-treated cells was significantly lower than in the PBT24 cells.…”

“…Histological specimens were stained with hematoxylin and eosin (H–E) and immunohistochemical (IHC) techniques. Preparation of fertilized eggs for the assay, tumor formation from the test cells, tumor transplantation onto the CAM in vivo, EDD time course biomicroscopy to assess the effect of the drug on tumor growth, neo-angiogenesis, and the histological examination of the tumor, assessment of the number of blood vessels in the CAM beneath the tumor, and the thickness of the CAM were performed in the same method as we have reported previously [ 37 ].…”

“…The expression of EZH2 and PCNA in tumor cells was measured by immunohistochemistry as described by us previously [ 37 ]. IHC analysis of p53 (aa 211-220, clone240, CBL404, Merck, Germany) and survivin expression was performed on tumors fixed for 24 h at 22 °C temperature with 10% formalin and paraffin-embedded using standard procedures.…”