Anti-PARP Antibody (A30245)

LF11-322 (PFWRIRIRR-NH2) (PFR peptide), a nine amino acid-residue peptide fragment derived from human lactoferricin, possesses potent cytotoxicity against bacteria. We report here the discovery and characterization of its antitumor activity in leukemia cells. PFR peptide inhibited the proliferation of MEL and HL-60 leukemia cells by inducing cell death in the absence of the classical features of apoptosis, including chromatin condensation, Annexin V staining, Caspase activation and increase of abundance of pro-apoptotic proteins. Instead, necrotic cell death as evidenced by increasing intracellular PI staining and LDH release, inducing membrane disruption and up-regulating intracellular calcium level, was observed following PFR peptide treatment. In addition to necrotic cell death, PFR peptide also induced G0/G1 cell cycle arrest. Moreover, PFR peptide exhibited favorable antitumor activity and tolerability in vivo. These findings thus provide a new clue of antimicrobial peptides as a potential novel therapy for leukemia.

Reactive oxygen species (ROS)-induced oxidative stress increases in skeletal muscle with aging and decreases the viability of implanted cells. Type 1 insulin-like growth factor (IGF-1) promotes the survival of skeletal muscle cells under oxidative stress. It is unknown whether IGF-1 protects muscle-derived stem cells (MDSCs) from oxidative stress. In this study, we genetically engineered rat MDSCs to overexpress IGF-1 and determined cell viability, apoptosis, and VEGF secretion under oxidative stress. Overexpression of IGF-1 prevented MDSCs from H2O2-induced caspase-dependent apoptotic cell death by upregulating the PI3K/AKT pathway, accompanied with an increase of NF-κB, p-NF-κB, Bcl-2, and VEGF, as well as a decrease of Bax. In contrast, pre-administration of picropodophyllinb, wortmannin, 1L-6-hydroxymethyl-chiro-inositol-2-((R)-2-O-methyl-3-O-octadecylcarbonate), or pyrrolidine-dithiocarbamate, specific inhibitors of IGF-1R, PI3K, AKT, and NF-κB, respectively, followed by treatment with H2O2, resulted in cell death of MDSCs. Our data indicated that IGF-1 suppresses apoptosis and enhances the paracrine function of MDSCs under oxidative stress via enhancing IGF-1R/PI3K/AKT signaling. Thus, IGF-1 gene-modified MDSCs present a potential application in the treatment of muscle wasting, such as urethra intrinsic sphincter deficiency.

Poly(ADP-ribose) polymerase-1 (PARP-1) which mediates poly-ADP-ribosylation, has been extensively investigated in carcinoma compared to arginine ADP-ribosyltransferase 1 (ART1), which mediates mono‑ADP‑ribosylation. Previous studies have demonstrated that these enzymes promote proliferation and tumor development in colon carcinoma. However, whether there is any association between PARP-1 and ATR1 in colon carcinoma, remains unelucidated. In this study, using immunohistochemical analysis, we detected a higher expression of PARP-1 and ART1 in 63 samples from patients with colon carcinoma compared to 10 samples of normal colonic mucosa; our results revealed a positive correlation between the expression of PARP-1 and ART1 in the 63 human colon carcinoma tissue samples. To determine the correlation between PARP-1 and ART1, inhibitors of PARP-1 and ART1 and lentivirus vector‑mediated ART1 short‑hairpin RNA (shRNA) were used to culture CT26 murine colon adenocarcinoma cells separately. Using double‑label immunofluorescence assay, we detected the expression of PARP-1 in the CT26 cells, which was decreased following treatment with 5‑aminoisoquinolinone (5-AIQ, a PARP-1 inhibitor) or meta‑iodobenzylguanidine (MIBG, an ART1 inhibitor). However, the expression of ART1 only decreased when the CT26 cells were treated with MIBG. Furthermore, our results demonstrated that silencing ART1 inhibited PARP‑1 expression by decreasing the expression of nuclear factor-κB (NF-κB), inhibiting ras homolog A (RhoA). Hence, our data demonstrate the positive correlation between ART1 and PARP-1; the inhibition of ART1 activity downregulates PARP-1 expression by decreasing the activity of NF-κB in CT26 colon carcinoma cells.

Baohuoside I (also known as Icariside II) is a flavonoid isolated from Epimedium koreanum Nakai. Although Baohuoside I exhibits anti-inflammatory and anti-cancer activities, its molecular targets/pathways in human lung cancer cells are poorly understood. Therefore, in the present study, we investigated the usefulness of Baohuoside I as a potential apoptosis-inducing cytotoxic agent using human adenocarcinoma alveolar basal epithelial A549 cells as in vitro model. The apoptosis induced by Baohuoside I in A549 cells was confirmed by annexin V/propidium iodide double staining, cell cycle analysis and dUTP nick end labeling. Further research revealed that Baohuoside I accelerated apoptosis through the mitochondrial apoptotic pathway, involving the increment of BAX/Bcl-2 ratio, dissipation of mitochondrial membrane potential, transposition of cytochrome c, caspase 3 and caspase 9 activation, degradation of poly (ADP-ribose) polymerase and the over-production of reactive oxygen species (ROS). A pan-caspase inhibitor, Z-VAD-FMK, only partially prevented apoptosis induced by Baohuoside I, while NAC, a scavenger of ROS, diminished its effect more potently. In addition, the apoptotic effect of Baohuoside I was dependent on the activation of ROS downstream effectors, JNK and p38(MAPK), which could be almost abrogated by using inhibitors SB203580 (an inhibitor of p38(MAPK)) and SP600125 (an inhibitor of JNK). These findings suggested that Baohuoside I might exert its cytotoxic effect via the ROS/MAPK pathway.