Phenylacetylglutaminate and Phenylacetate in Combination Upregulate VDUP1, Cause Cell Cycle Blockade and Apoptosis in U87 Glioblastoma Cells

Abstract

Phenylacetylglutaminate (PG) and Phenylacetate (PN) are metabolites of Phenylbutyrate (PB) and are constituents of antineoplaston AS2-1. These are sodium salts of amino acid derivative and carboxylic acid that inhibit the growth of neoplastic cells without growth inhibitory effect in normal cells. The aim of this study was to identify molecular pathways involved in the anti-proliferative effect of antineoplastons. Using a total human genome microarray we have found that 1) Vitamin D3 upregulated protein (VDUP1) is significantly upregulated in response to PG and PN in the U87 glioblastoma cells; 2) Isobologram analysis shows that PG and PN act in an additive or synergistic manner to effectively suppress proliferation of U87 cells; 3) PG and PN cause cell cycle arrest, changes in expression of several cell cycle genes and suppress expression and activity of the G2/M checkpoint kinase, CHK1. The multiple cellular targets possibly make these compounds effective anti-proliferative agents. We propose that PG and PN in combination target important cellular pathways and upregulate VDUP1 leading to detachment-induced apoptosis in cancer cells.

The Effect of Antineoplastons A10 and AS2-1 and Metabolites of Sodium Phenylbutyrate on Gene Expression in Glioblastoma Multiforme

“…PG and PN decrease expression of AKT2 gene by 55% and increase expression of TXNIP over 30 times [28] This was also confirmed by qPCR, Table 1.…”

“…PG and PN effect expression of the genes at the most important cell cycle checkpoint: G1/S, G2/M, and the spindle assembly (exit M) [28]. Among the most important proteins involved in the checkpoints are cyclin-dependent kinases (CDKs).…”

“…PCNA, BRAF, CCND3, CDK2, CDK4, Dp1, E2F1, and CHK1 (30% -59%), and increase the expression of TP53 and p21 genes (over 2 times) [28] Table 1. The effect of PG and PN on the expression of genes at G1/S checkpoint should prohibit the entry of GBM cells into S-phase of cell cycle.…”

“…Due to the action of TXNIP, p27 kip1 is stabilized and retained in the nucleus where it exerts its inhibitory activity on cell cycle in malignant cells [28].…”

“…viously presented and published [27] [28]. In vivo experiments in animal models of different types of cancer have been performed and published, but such studies of GBM are planned in the future.…”