Mitochonic Acid 5 Improves Duchenne Muscular Dystrophy and Parkinson’s Disease Model of Caenorhabditis elegans

Mitochonic Acid 5 (MA-5) enhances mitochondrial ATP production, restores fibroblasts from mitochondrial disease patients and extends the lifespan of the disease model “Mitomouse”. Additionally, MA-5 interacts with mitofilin and modulates the mitochondrial inner membrane organizing system (MINOS) in mammalian cultured cells. Here, we used the nematode Caenorhabditis elegans to investigate whether MA-5 improves the Duchenne muscular dystrophy (DMD) model. Firstly, we confirmed the efficient penetration of MA-5 in the mitochondria of C. elegans. MA-5 also alleviated symptoms such as movement decline, muscular tone, mitochondrial fragmentation and Ca2+ accumulation of the DMD model. To assess the effect of MA-5 on mitochondria perturbation, we employed a low concentration of rotenone with or without MA-5. MA-5 significantly suppressed rotenone-induced mitochondria reactive oxygen species (ROS) increase, mitochondrial network fragmentation and nuclear destruction in body wall muscles as well as endogenous ATP levels decline. In addition, MA-5 suppressed rotenone-induced degeneration of dopaminergic cephalic (CEP) neurons seen in the Parkinson’s disease (PD) model. Furthermore, the application of MA-5 reduced mitochondrial swelling due to the immt-1 null mutation. These results indicate that MA-5 has broad mitochondrial homing and MINOS stabilizing activity in metazoans and may be a therapeutic agent for these by ameliorating mitochondrial dysfunction in DMD and PD

NF-kappa B signaling mediates acquired resistance after PARP inhibition

PARP inhibitors are a class of promising anti-cancer drugs, with proven activity in BRCA mutant cancers. However, as with other targeted agents, treatment with PARP inhibitors generates acquired resistance within these tumors. The mechanism of this acquired resistance is poorly understood. We established cell lines that are resistant to PARP inhibitor by continuous treatment with the drug, and then used RNA sequencing to compare gene expression. Pathway analysis on the RNA sequencing data indicates that NF-kappa B signaling is preferentially up-regulated in PARP inhibitor-resistant cells, and that knockdown of core components in NF-kappa B signaling reverses the sensitivity to PARP inhibitor in resistant cells. Of therapeutic relevance, we show that PARP inhibitor-resistant cells are sensitive to an NF-kappa B inhibitor in comparison to their parental controls. Malignancies with up-regulation of NF-kappa B are sensitive to bortezomib, a proteasome inhibitor that is currently used in the clinic. We also show that treatment with bortezomib results in cell death in the PARP inhibitor-resistant cells, but not in parental cells. Therefore we propose that up-regulation of NF-kappa B signaling is a key mechanism underlying acquired resistance to PARP inhibition, and that NF-kappa B inhibition, or bortezomib are potentially effective anti-cancer agents after the acquisition of resistance to PARP inhibitors.We thank Dr. Grahame McKenzie for the kind gift of plasmids for luciferase assay. This work was supported by St. Marianna University Grant.S

LSD1 overexpression is associated with poor prognosis in basal-like breast cancer, and sensitivity to PARP inhibition.

LSD1, a lysine-specific histone demethylase, is overexpressed in several types of cancers and linked to poor outcomes. In breast cancer, the significance of LSD1 overexpression is not clear. We have performed an in silico analysis to assess the relationship of LSD1 expression to clinical outcome. We demonstrate that LSD1 overexpression is a poor prognostic factor in breast cancer, especially in basal-like breast cancer, a subtype of breast cancer with aggressive clinical features. This link is also observed in samples of triple negative breast cancer. Interestingly, we note that overexpression of LSD1 correlates with down-regulation of BRCA1 in triple negative breast cancer. This phenomenon is also observed in in vitro models of basal-like breast cancer, and is associated with an increased sensitivity to PARP inhibitors. We propose therefore that high expression levels of the demethylase LSD1 is a potential prognostic factor of poor outcome in basal-like breast cancer, and that PARP inhibition may be a therapeutic strategy of interest in this poor prognostic subtype with overexpression of LSD1

Overexpression of LSD1 is observed only in basal-like breast cancer.

<p>This is a plot of LSD1 expression from the TCGA dataset (expression of mRNA as log₂ TMM-normalized raw counts in the y-axis) plotted across different subtypes of breast cancer (x-axis). Significant differences in mRNA between intrinsic subtypes were calculated using edgeR. The number of samples were as shown in the scatter plots. LSD1 is amplified in basal-like breast cancer when compared to other subtypes, in this dataset.</p

mRNA expression of LSD1 in subtypes of breast cancer.

<p>False discovery rate calculated by edgeR are also shown as q-value.</p><p>mRNA expression of LSD1 in subtypes of breast cancer.</p

Overexpression of LSD1 is linked to poor outcome in triple negative breast cancer.

<p>Representative images of immunohistochemistry of LSD1 in 20 clinical samples are shown (A and B, LSD1 high and low, respectively). The Kaplan Meir curve compares the recurrence free survival of cancer with high or low level LSD1 protein products (C). Definition of LSD1 high is samples that have IHC scores above 5.</p

mRNA expression of LSD1 in subtypes of breast cancer.

<p>False discovery rate calculated by edgeR are also shown as q-value.</p><p>mRNA expression of LSD1 in subtypes of breast cancer.</p

Overexpression of LSD1 reduces BRCA1 expression in triple negative or in basal-like breast cancer and increases sensitivity to PARP inhibitor in basal-like breast cancer.

<p>Histogram shows protein expression of BRCA1 in triple negative breast cancer with high or low level of LSD1 protein (A). Y-axis indicates IHC score of BRCA1. Basal-like breast cancer cell lines (MDA-MB-231, MDA-MB-157 and HCC70) was transfected as indicated. Cell lysates were subjected for Western Blots with indicated antibodies (B). Cell viability of basal-like breast cancer cell lines are assessed by colony formation assay. Percent survival is shown in different doses of PARP inhibitor. Error bars show standard deviation of three independent experiments (C-E).</p

Cox proportional hazard model for clinical samples.

<p>Age was evaluated as a continuous variable.</p><p>Cox proportional hazard model for clinical samples.</p

Protein expression of BRCA1 and LSD1 in triple negative breast cancer.

<p>IHC score are shown.</p><p>IHC score = SI*PP (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0118002#sec002" target="_blank">material and methods</a>)</p><p>Protein expression of BRCA1 and LSD1 in triple negative breast cancer.</p