Treatment of malignant melanoma by downregulation of XIAP and overexpression of TRAIL with a conditionally replicating oncolytic adenovirus

Transcriptome Analysis of Natural Killer Cells in Response to Newcastle Disease Virus Infected Hepatocellular Carcinoma Cells

When tumor cells are infected by the Newcastle disease virus (NDV), the lysis of tumor cells by natural killer (NK) cells is enhanced, which may be related to the enhanced NK cell activation effect. To better understand the intracellular molecular mechanisms involved in NK cell activation, the transcriptome profiles of NK cells stimulated by NDV-infected hepatocellular carcinoma (HCC) cells (NDV group) and control (NC group, NK cells stimulated by HCC cells) were analyzed. In total, we identified 1568 differentially expressed genes (DEGs) in the NK cells of the NDV group compared to the control, including 1389 upregulated and 179 downregulated genes. Functional analysis showed that DEGs were enriched in the immune system, signal transmission, cell growth, cell death, and cancer pathways. Notably, 9 genes from the IFN family were specifically increased in NK cells upon NDV infection and identified as potential prognosis markers for patients with HCC. A qRT-PCR experiment was used to confirm the differential expression of IFNG and the other 8 important genes. The results of this study will improve our understanding of the molecular mechanisms of NK cell activation.

MicroRNA-509-3p inhibits cell proliferation and invasion via downregulation of X-linked inhibitor of apoptosis in glioma

Malignant glioma is an aggressive type of cancer. Increasing evidence has suggested that microRNAs (miRs) regulate gene expression post-transcriptionally to affect cancer development and progression. Aberrant expression of miR-509-3p has been reported in cancer studies. However, the expression and mechanism of its function in glioma remains unclear. The present study demonstrated that miR-509-3p was downregulated in glioma tissue samples relative to non-tumor tissues, and that low miR-509-3p expression was associated with a reduced overall survival time. Functional studies revealed that the overexpression of miR-509-3p inhibited cell proliferation, induced apoptosis and suppressed cell migration and invasion via negatively regulating the expression of X-linked inhibitor of apoptosis. The data therefore suggested that miR-509-3p serves an important role in the development and progression of glioma, implicating its possible application in clinical practice as a biomarker and a potential novel therapeutic target.

sTRAIL-iRGD is a promising therapeutic agent for gastric cancer treatment

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively kills tumor cells and augments chemotherapeutics in vivo. Here, we developed sTRAIL-iRGD, a recombinant protein consisting of sTRAIL fused to CRGDKGPDC, a C-terminal end binding peptide with an integrin-binding arginine-glycine-aspartic acid (iRGD) motif. CRGDKGPDC is a tumor-homing peptide with high penetration into tumor tissue and cells. We found that sTRAIL-iRGD internalized into cultured gastric cancer tumor cells and localized to both the tumor mass in vivo and three-dimensional multicellular spheroids in vitro. sTRAIL-iRGD had an antitumor effect in tumor cell lines, multicellular spheroids and nude mice with tumors. Repeated treatment with sTRAIL-iRGD reduced tumor growth and volume in vivo. Mice treated with sTRAIL-iRGD and paclitaxel (PTX) in combination showed no sign of sTRAIL-iRGD-related liver toxicity. Our data suggest that sTRAIL-iRGD is a promising anti-gastric cancer agent with high selectivity and limited systemic toxicity.

XIAP associated factor 1 (XAF1) represses expression of X-linked inhibitor of apoptosis protein (XIAP) and regulates invasion, cell cycle, apoptosis, and cisplatin sensitivity of ovarian carcinoma cells

BACKGROUND

X-linked inhibitor of apoptosis protein (XIAP) associated factor 1 (XAF1) exhibits aberrantly low or absent expression in various human malignancies, closely associated with anti-apoptosis and overgrowth of cancer cells. However, limited attention has been directed towards the contribution of XAF1 to invasion, apoptosis, and cisplatin (DDP)-resistance of epithelial ovarian cancer (EOC) cells. This study aimed to evaluate the potential effects of XAF1 on invasion, cell cycle, apoptosis, and cisplatin-resistance by overexpressing XAF1 in SKOV-3 and SKOV-3/DDP cells.

METHODS AND RESULTS

The pEGFP-C1-XAF1 plasmid was transfected into SKOV-3 and SKOV-3/DDP cells, and the expression of XAF1 at both mRNA and protein levels was analyzed by reverse transcription-PCR and Western blotting. Overexpression of XAF1 suppressed XIAP expression in both SKOV-3 and SKOV-3/DDP cells. Transwell invasion assays demonstrated that XAF1 exerted a strong anti-invasive effect in XAF1-overexpressing cells. Moreover, flow cytometry analysis revealed that XAF1 overexpression arrested the cell cycle at G0/G1 phase, and cell apoptosis analysis showed that overexpression of XAF1 enhanced apoptosis of SKOV-3 and SKOV-3/DDP cells apparently by activating caspase-9 and caspase-3. Furthermore, MTT assay confirmed a dose-dependent inhibitory effect of cisplatin in the tested tumor cells, and overexpression of XAF1 increased the sensitivity of SKOV-3 and SKOV-3/DDP cells to cisplatin-mediated anti- proliferative effects.

CONCLUSIONS

In summary, our data indicated that overexpression of XAF1 could suppress XIAP expression, inhibit invasion, arrest cell cycle, promote apoptosis, and confer cisplatin-sensitivity in SKOV-3 and SKOV-3/DDP cells. Therefore, XAF1 may be further assessed as a potential target for the treatment of both cisplatin-resistant and non-resistant EOCs.

Effect of Embelin on TRAIL receptor 2 mAb-induced apoptosis of TRAIL-resistant A549 non-small cell lung cancer cells

INTRODUCTION

Some non-small cell lung cancer (NSCLC) tumor cells are insensitive to tumor necrosis factor- related apoptosis-inducing ligand (TRAIL) -based therapy. This study was conducted to examine the effect of embelin on the sensitivity of the A549 NSCLC cell line to TRAIL receptor2 (TRAILR2) monoclonal antibodies and to investigate the potential mechanisms.

MATERIALS AND METHODS

A549 cells were treated with embelin, TRAILR2 mAb or a combination of both. Cell viability was measured using ATPlite assay and apoptosis rates were determined by flow cytometry with AnnexinV-FITC and propidium iodide staining, with the expression levels of proteins analyzed by Western blotting.

RESULTS

The cell survival rate of separate treatments with 100 ng/ml TRAILR2 antibody or 25 uM embelin were 81.5±1.57% and 61.7±2.84%, respectively. Their combined use markedly decreased cell viability in A549 cells to 28.1±1.97% (P<0.05). The general caspase inhibitor Z-VAD- FMK could inhibit the embelin-enhanced sensitivity of A549 cells to TRAILR2 mAb (75.97±3.17%)(P<0.05). Both flow cytometry and cell morphological analysis showed that embelin was able to increase TRAIL-induced apoptosis in A549 cells. Combined treatment with embelin and TRAILR2 mAb augmented the activation of initiator caspases and effector caspase. In addition, A549 cells showed increasing levels of TRAILR2 protein and decreasing levels of Bcl-2, survivin and c-FLIP following the treatment with embelin+TRAILR2 mAb.

CONCLUSIONS

Embelin could enhance TRAIL-induced apoptosis in A549 cells. The synergistic effect of the combination treatment might be due to modulation of multiple components in the TRAIL receptor-mediated apoptotic signaling pathway, including TRAILR2, XIAP, survivin, Bcl-2 and c-FLIP.