Antiviral Activities of Methylated Nordihydroguaiaretic Acids. 2. Targeting Herpes Simplex Virus Replication by the Mutation Insensitive Transcription Inhibitor Tetra-O-methyl-NDGA

Abstract

We had previously reported that tetramethyl-O-NGDA (M4N), a synthetic derivative of the naturally occurring nordihydroguaiaretic acid (NDGA), is able to inhibit HIV Tat transactivation by blocking host Sp1 protein at the Sp1 cognate binding site on the HIV LTR promoter. The present studies were undertaken to examine whether M4N is able to inhibit the replication of herpes simplex virus (HSV), another Sp1-regulated virus. The results showed that in Vero cells, M4N inhibits at micromolar levels (IC50 = 43.5 microM) the expression of the herpes immediate early gene (alpha-ICP4), which is essential for HSV replication. An electrophoretic mobility shift assay, examining Sp1 binding to the alpha-ICP4 promoter, showed a significant inhibition of the control bands: 88% inhibition of the fast moving band (FMB) and 45% of the slow moving band (SMB), at 100 microM of drug concentration. Comparative studies between M4N and acycloguanosine (acyclovir, ACV) in cultured Vero cells revealed an interesting pattern in the drug sensitivity (IC50) and cytotoxicity (TC50) parameters. For M4N, the IC50 varied between 11.7 and 4 microM in 10 passages of HSV-1 and 4 passages of HSV-2 with no indication for a requirement of higher drug concentration. In contrast, for acyclovir, the IC50 increased from 7 microM in the first passage to 444 microM in the tenth passage of HSV-1, and >88 microM for the fourth passage of HSV-2, indicating a rapid build-up of drug resistance against acyclovir. While the selective index (SI), defined as the ratio: TC50/IC50, remained relatively constant for M4N; it dropped 60-fold for acyclovir in the endpoints of viral passages. Drug sensitivity for M4N toward the acyclovir-sensitive strain (sm44) and the acyclovir-resistant strain (ACV-10) of HSV-1 was similar, indicating no cross-resistance between M4N and acyclovir in their anti-HSV effects. These results may have an important clinical relevance since HSV has been shown to be a factor for spreading of HIV.

Antiviral Activity of Nordihydroguaiaretic Acid and Its Derivative Tetra- O -Methyl Nordihydroguaiaretic Acid against West Nile Virus and Zika Virus

“…This antiviral effect of NDGA is consistent with results obtained for DENV and HCV (9,10). It has to be remarked that the antiviral effects of NDGA or M 4 N also have been observed against viruses from other viral families, such as herpes simplex virus, human immunodeficiency virus, human papillomavirus, cowpox virus, and vaccinia virus (30)(31)(32)(33)(34). Regarding the mechanism behind the antiviral activity of NDGA, in the case of HCV, it was related to an inhibition of the SREBP pathway (10).…”

MYD88-independent growth and survival effects of Sp1 transactivation in Waldenström macroglobulinemia

“…TMP is a semi-synthetic small molecule that disrupts the interaction between Sp1 and guanine-cytosinerich motifs, thereby inhibiting Sp1 transcriptional activity. 8,[18][19][20] We have observed the inhibition of Sp1 binding to known Sp1-responsive promoters by TMP using chromatin immunoprecipitation assay, and decreased expression levels of Sp1-regulated proteins, confirming that the antitumor activity of TMP in WM occurs via selective targeting of Sp1 activity.…”

Tetra- O -methyl nordihydroguaiaretic acid induces growth arrest and cellular apoptosis by inhibiting Cdc2 and survivin expression

“…Our previous studies showed that M 4 N prevents Sp1 binding to its cognate binding sites in the promoter regions of Sp1-dependent genes (2,3). Given that the expression of survivin is Sp1-dependent (17,18), and our finding that M 4 N induces caspase-3 activation, we next investigated the effect of M 4 N on survivin gene expression.…”

“…We found earlier that an anti-HIV proviral transcriptional inhibitor, tetra-O-methyl nordihydroguaiaretic acid (M 4 N) (2,3), was able to cause growth arrest of a variety of transformed human and mouse cells in culture and in mice (4). As we have previously reported that 3-O-methyl-NDGA (Mal.4) inhibited HIV proviral transcription by specifically blocking Sp1 transcriptional factor to bind HIV long-terminal repeats (5), M 4 N, a DNA major groove binder for G͞C-rich sequence, was found to block cell-cycle progression at G 2 ͞M by inhibiting the transcription of an Sp1-dependent gene coding for cyclin-dependent kinase (Cdc2).…”