Isoplumbagin (5-hydroxy-3-methyl-1,4-naphthoquinone), a naturally occurring quinone from Lawsonia inermis and Plumbago europaea, has been reported to have anti-inflammatory and antimicrobial activity. Inflammation has long been implicated in cancer progression. In this study, we examined the anticancer effect of chemically synthesized isoplumbagin. Our results revealed that isoplumbagin treatment suppressed cell viability and invasion of highly invasive oral squamous cell carcinoma (OSCC) OC3-IV2 cells, glioblastoma U87 cells, non-small cell lung carcinoma H1299 cells, prostate cancer PC3 cells, and cervical cancer HeLa cells by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Boyden chamber assays. In vivo studies demonstrate the inhibitory effect of 2 mg/kg isoplumbagin on the growth of orthotopic xenograft tumors derived from OSCC cells. Mechanistically, isoplumbagin exerts its cytotoxic effect through acting as a substrate of reduced nicotinamide adenine dinucleotide phosphate [NAD(P)H] dehydrogenase quinone 1 (NQO1) to generate hydroquinone, which reverses mitochondrial fission phenotype, reduces mitochondrial complex IV activity, and thus compromises mitochondrial function. Collectively, this work reveals an anticancer activity of isoplumbagin mainly through modulating mitochondrial dynamics and function.

The solution structure and hydration of a DNA.RNA hybrid chimeric duplex [d(CGC)r(amamam)d(TTTGCG)]2 in which the RNA adenines were substituted by 2'-O-methylated riboadenines was determined using two-dimensional NMR, simulated annealing, and restrained molecular dynamics. Only DNA residue 7T in the 2'-OMe-RNA.DNA junction adopted an O4'-endo sugar conformation, while the other DNA residues including 3C in the DNA.2'-OMe-RNA junction, adopted C1'-exo or C2'-endo conformations. The observed NOE intensity of 2'-O-methyl group to H1' proton of 4am at the DNA.2'-OMe-RNA junction is much weaker than those of 5am and 6am. The 2'-O-methyl group of 4am was found to orient towards the minor groove in the trans domain while the 2'-O-methyl groups of 5am and 6am were found to be in the gauche (+) domain. In contrast to the long-lived water molecules found close to the RNA adenine H2 and H1' protons and the methyl group of 7T in the RNA-DNA junction of [d(CGC)r(aaa)d(TTTGCG)]2, there were no long-lived water molecules found in [d(CGC)r(amamam)d(TTTGCG)]2. This is probably due to the hydrophobic enviroment created by the 2'-O-methylated riboadenines in the minor groove or due to the wider minor groove width in the middle of the structure. In addition, the 2'-O-methylation of riboadenines in pure chimeric duplex increses its melting temperature from 48.5 degrees C to 51.9 degrees C. The characteristic structural features and hydration patterns of this chimeric duplex provide a molecular basis for further therapeutic applications of DNA.RNA hybrid and chimeric duplexes with 2'-modified RNA residues.

Isoplumbagin (5-hydroxy-3-methyl-1,4-naphthoquinone), a naturally occurring quinone from Lawsonia inermis and Plumbago europaea, that has been reported to have anti-inflammatory and anti-microbial activity.Inflammation has long been implicated in cancer progression. In this study, we examined the anti-cancer effect of chemically-synthesized isoplumbagin. Our results revealed that isoplumbagin treatment suppressed cell viability and invasion of highly invasive oral squamous cell carcinoma (OSCC) OC3-IV2 cells, glioblastoma U87 cells, non-small cell lung carcinoma H1299 cells, prostate cancer PC3 cells, and cervical cancer Hela cells by using MTT and Boyden chamber assays. In vivo studies demonstrate the inhibitory effect of 2 mg/kg isoplumbagin on the growth of orthotopic xenograft tumors derived from OSCC cells.Mechanistically, isoplumbagin exerts its cytotoxic effect through acting as a substrate of NAD(P)H quinone dehydrogenase 1 (NQO1) to generate hydroquinone, which reverses mitochondrial fission phenotype, reduces mitochondrial complex IV activity and thus compromises mitochondrial function. Collectively, this work reveals an anti-cancer activity of isoplumbagin mainly through modulating mitochondrial dynamics and function.

Background An important contributor to the pathogenesis of the autoimmune disease systemic lupus erythematosus (SLE) is the impaired clearance of apoptotic cells (efferocytosis) and increasing evidence implicates microbiota dysbiosis as another important player. Hydroxychloroquine (HCQ) is frequently prescribed for the treatment of SLE. Here, we evaluate changes in efferocytosis and the gut microbiome in mice with pristane-induced lupus (PIL) by HCQ administration. Methods PIL mice were studied with or without HCQ and/or resveratrol (RESV). Efferocytosis was determined in RAW 264.7 cells and peritoneal macrophages from mouse ascites fluid. The gut microbiome was analyzed using Illumina sequencing. Results Both HCQ and RESV enhanced efferocytosis. HCQ also significantly suppressed ascites production of proinflammatory cytokines interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α). The Firmicutes/Bacteroidetes (F/B) ratio was significantly decreased in PIL mice compared with untreated controls (p<0.05). The F/B ratio in PIL mice was increased by HCQ alone and significantly increased by HCQ combined with RESV. Conclusions In this study, HCQ and RESV enhanced efferocytosis in both RAW 264.7 cells and peritoneal macrophages of PIL mice. The pristane-induced reduction in the F/B ratio was restored by HCQ treatment. SLE treatment should consider the role of the gut microbiome.

Background An important contributor to the pathogenesis of the autoimmune disease systemic lupus erythematosus (SLE) is the impaired clearance of apoptotic cells (efferocytosis) and increasing evidence implicates microbiota dysbiosis as another important player. The disease-modifying antirheumatic drug hydroxychloroquine (HCQ) is frequently prescribed for the treatment of SLE. Here, we evaluate changes in efferocytosis and the gut microbiome in mice with pristane-induced lupus (PIL) before and after HCQ administration.Methods PIL mice were studied with or without HCQ and/or resveratrol (RESV). Efferocytosis was determined in RAW 264.7 cells and peritoneal macrophages from mouse ascites fluid. The gut microbiome was analyzed using Illumina sequencing targeting the 16S ribosomal DNA gene (rDNA) amplicon sequencing.Results Both HCQ and RESV enhanced efferocytosis. HCQ also significantly suppressed ascites production of proinflammatory cytokines interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α). The Firmicutes/Bacteriodetes (F/B) ratio was significantly decreased in PIL mice compared with untreated controls (p<0.05). The F/B ratio in PIL mice was increased by HCQ alone and significantly increased by HCQ combined with RESV. Alpha- and beta-diversity differed between mice administered RESV and those that were not. Viable counts of lactic acid bacteria Lactobacillaceae, Lactobacillus and Lactobacillales were increased by RESV plus HCQ treatment.Conclusions In this study, HCQ and RESV enhanced efferocytosis in both RAW 264.7 cells and peritoneal macrophages of PIL mice and suppressed IL-6 and TNF-α production in ascites fluid. The pristane-induced reduction in the F/B ratio was restored by HCQ treatment. SLE treatment should consider the role of the gut microbiome.