Diamond Nanoparticles Downregulate Expression of CycD and CycE in Glioma Cells

Abstract

Our previous studies have shown that diamond nanoparticles (NDs) exhibited antiangiogenic and proapoptotic properties in vitro in glioblastoma multiforme (GBM) cells and in tumors in vivo. Moreover, NDs inhibited adhesion, leading to the suppression of migration and invasion of GBM. In the present study, we hypothesized that the NDs might also inhibit proliferation and cell cycle in glioma cells. Experiments were performed in vitro with the U87 and U118 lines of GBM cells, and for comparison, the Hs5 line of stromal cells (normal cells) after 24 h and 72 h of treatment. The analyses included cell morphology, cell death, viability, and cell cycle analysis, double timing assay, and gene expression (Rb, E2F1, CycA, CycB, CycD, CycE, PTEN, Ki-67). After 72 h of ND treatment, the expression level of Rb, CycD, and CycE in the U118 cells, and E2F1, CycD, and CycE in the U87 cells were significantly lower in comparison to those in the control group. We observed that decreased expression of cyclins inhibited the G1/S phase transition, arresting the cell cycle in the G0/G1 phase in glioma cells. The NDs did not affect the cell cycle as well as PTEN and Ki-67 expression in normal cells (Hs5), although it can be assumed that the NDs reduced proliferation and altered the cell cycle in fast dividing cells.

Stearoyl CoA Desaturase-1 Silencing in Glioblastoma Cells: Phospholipid Remodeling and Cytotoxicity Enhanced upon Autophagy Inhibition

“…As shown in Figure 1 A, U87 cells grown in standard serum conditions (10% FBS) presented a doubling time of ca. 33 h, in agreement with previous reports [ 14 , 15 ], but the reduction of the serum concentration to 2% increased the cell-doubling time by 6 h. Under these rate-limiting conditions, the expression of SCD1 protein in U87 cells increased significantly ( Figure 1 B), as compared to that in cells grown in 10% FBS and in normal human astrocytes (NHAs). It should be noted that NHAs are commonly cultured under low serum [ 16 ], conditions that were also employed herein, by supplementing the culture medium with 2% FBS [ 17 , 18 ].…”

Mechanisms of nanoparticle radiosensitization

“…Proliferative ability of cells was also reduced (i.e., prolongation of doubling time) by nanodiamonds, shown for U87 and U118 glioblastoma cells via cell cycle arrest (Grodzik et al, 2019). Nanodiamonds arrested cells in the G 0 /G 1 phase after 72 hr incubation.…”

A Comprehensive Assessment of the Biocompatibility and Safety of Diamond Nanoparticles on Reconstructed Human Epidermis

“…Detonation-produced diamond nanoparticles, purchased from SkySpring Nanomaterials, have found extensive applications in various fields. One potential application of these compounds lies in their use to investigate undesirable cytotoxicity in normal cells and assess their ability to induce expected cytotoxic effects while also modulating the expression of factors that improve invasiveness in diverse cancer cell lines [ 38 , 39 , 40 , 41 ]. Furthermore, safety studies conducted on rats demonstrated that the intraperitoneal administration of 500 μg/mL of these diamond nanoparticles did not have any toxic effects on blood parameters or rat growth, suggesting their potential use as remedies or in drug delivery systems [ 42 ].…”