Silymarin is a polyphenolic flavonoid from milk thistle (Silybum marianum), which has anti-inflammatory, cytoprotective as well as antioxidant effects. Our previous study demonstrated that silymarin has anti-apoptotic effect against UV irradiation. In this study, we assessed the effect of silymarin on anti-Fas agonistic antibody CH11-treated human malignant melanoma, A375-S2 cells. Pretreatment with silymarin (3 x 10(- 4) mol/L) significantly induced cell apoptosis in CH11-treated A375-S2 cells. Mitochondrial transmembrane potential (DeltaPsi(m)) was also down-regulated by silymarin pretreatment. Caspase-8, -9, -3 and pan-caspase inhibitors partially reversed silymarin-induced apoptosis of CH11-treated cells. The expression of Fas-associated proteins with death domain (FADD), a downstream molecule of the death receptor pathway, was increased by silymarin pretreatment, followed by cleavage of procaspase-8, whose activation induced cell apoptosis. Moreover, cleavage of procaspase-3 and digestion of its substrate, the inhibitor of caspase-activated DNase (ICAD), were also increased by silymarin pretreatment. These results suggested that silymarin could also exaggerate the apoptotic effect of anti-Fas agonistic antibody CH11 on A375-S2 cells.

Inhibition of nicotinamide phosphoribosyltransferase (NAMPT) is an attractive therapeutic strategy for targeting cancer metabolism. So far, many potent NAMPT inhibitors have been developed and shown to bind to two unique tunnel-shaped cavities existing adjacent to each active site of a NAMPT homodimer. However, cytotoxicities and resistances to NAMPT inhibitors have become apparent. Therefore, there remains an urgent need to develop effective and safe NAMPT inhibitors. Thus, we designed and synthesized two close structural analogues of NAMPT inhibitors, azaindole–piperidine (3a)- and azaindole–piperazine (3b)-motif compounds, which were modified from the well-known NAMPT inhibitor FK866 (1). Notably, 3a displayed considerably stronger enzyme inhibitory activity and cellular potency than did 3b and 1. The main reason for this phenomenon was revealed to be due to apparent electronic repulsion between the replaced nitrogen atom (N1) of piperazine in 3b and the Nδ atom of His191 in NAMPT by our in silico binding mode analyses. Indeed, 3b had a lower binding affinity score than did 3a and 1, although these inhibitors took similar stable chair conformations in the tunnel region. Taken together, these observations indicate that the electrostatic enthalpy potential rather than entropy effects inside the tunnel cavity has a significant impact on the different binding affinity of 3a from that of 3b in the disparate enzymatic and cellular potencies. Thus, it is better to avoid or minimize interactions with His191 in designing further effective NAMPT inhibitors.

In this study, Clostridium butyricum TO-A culture supernatant (CBCS) or butyric acid was added to a culture medium of human cervical carcinoma HeLa S3 cells, and changes in DNA-repair-related gene promoter activities were investigated. The HeLa S3 cells were transfected with a luciferase (Luc) expression vector containing approximately 500 bp of the 5′-upstream region of several human DNA-repair-related genes and cultured with a medium containing the CBCS (10%) or butyric acid (2.5 mM). The cells were harvested after 19 to 42 h of incubation. A Luc assay revealed that the human ATM, PARG, PARP1, and RB1 gene promoter activities were significantly increased. A Western blot analysis showed that the amounts of the proteins encoded by these genes markedly increased. Furthermore, 8, 24, and 48 h after the addition of the CBCS (10%), total RNA was extracted and subjected to RNAseq analysis. The results showed that the expression of several inflammation- and DNA-replication/repair-related genes, including NFKB and the MCM gene groups, decreased markedly after 8 h. However, the expression of the histone genes increased after 24 h. Elucidation of the mechanism by which the CBCS and butyrate affect the expression of genes that encode DNA-repair-associated proteins may contribute to the prevention of carcinogenesis, the risk of which rises in accordance with aging.

Cancer is widely known as a “genetic disease” because almost all cancers involve genomic mutations. However, cancer could also be referred to as a metabolic disease because it mainly depends on glycolysis to produce adenosine triphosphate (ATP) and is frequently accompanied by dysfunctions in the mitochondria, which are the primary organelle required in all eukaryotic cells. Importantly, almost all (99%) mitochondrial proteins are encoded by host nuclear genes. Not only cancer but also aging-related diseases, including neurodegenerative diseases, are associated with a decline in mitochondrial functions. Importantly, the nicotinamide adenine dinucleotide (NAD⁺) level decreases with aging. This molecule not only plays important roles in metabolism but also in the DNA repair system. In this article, we review 5′-upstream regions of mitochondrial function-associated genes to discuss the possibility of whether NAD⁺ is involved in transcriptional regulations. If the expression of these genes declines with aging, this may cause mitochondrial dysfunction. In this regard, cancer could be referred to as a “transcriptional disease”, and if so, novel therapeutics for cancer will need to be developed.

GGAA motifs in the human TP53 and HELB gene promoters play a part in responding to trans‑resveratrol (Rsv) in HeLa S3 cells. This sequence is also present in the 5'‑upstream region of the human CDC45 gene, which encodes a component of CMG DNA helicase protein complex. The cells were treated with Rsv (20 µM), then transcripts and the translated protein were analyzed by quantitative RT‑PCR and western blotting, respectively. The results showed that the CDC45 gene and protein expression levels were induced after the treatment. To examine whether they were due to the activation of transcription, a 5'‑upstream 556‑bp of the CDC45 gene was cloned and inserted into a multi‑cloning site of the Luciferase (Luc) expression vector. In the present study, various deletion/point mutation‑introduced Luc expression plasmids were constructed and they were used for the transient transfection assay. The results showed that the GGAA motif, which is included in a putative RELB protein recognizing sequence, plays a part in the promoter activity with response to Rsv in HeLa S3 cells.

In this study, Clostridium butyricum TO-A culture supernatant (CBCS) or butyric acid was added to a culture medium of human cervical carcinoma HeLa S3 cells, and changes in DNA repair-related gene promoter activi-ties were investigated. HeLa S3 cells were transfected with a luciferase (Luc) expression vector containing ap-proximately 500-bp of the 5′-upstream region of several human DNA repair-related genes and cultured with a medium containing CBCS (10%) or butyric acid (2.5 mM). Cells were harvested after 19 to 42 h of incubation. Luc assay revealed that the human ATM, PARG, PARP1, and RB1 gene promoter activities were significantly increased. Western blot analysis showed that amounts of the proteins encoded by those genes markedly in-creased. Furthermore, 8, 24, and 48 h after the addition of the CBCS (10%), total RNA was extracted and subjected to RNAseq analysis. The result showed that the expression of several DNA replication/repair-related genes, including NFKB, and the MCM gene groups, decreased markedly after 8 h. However, the expression of the histone genes increased after 24 h. Elucidation of the mechanism by which CBCS and butyrate affect DNA-repair associated protein-encoding gene expression may contribute to the prevention of carcinogenesis, of which the risk rises in accordance with aging.