Abstract. 5-Lipoxygenase (5-LOX) has been implicated in the development and progression of lung, pancreatic and esophageal cancers. However, its role in hepatocellular carcinoma (HCC) remains unclear. This study aimed to explore the role of 5-LOX in the pathogenesis of HCC. The expression of 5-LOX was detected in human HCC, HepG2 cells and diethylnitrosamine (DEN)-induced rat HCC using immunohistochemistry (IHC) staining or reverse transcriptase-polymerase chain reaction. Apoptosis in rat HCC was evaluated by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) assay. Cell viability and apoptosis were determined in HepG2 cells by MTT assay and flow cytometry, respectively. IHC staining showed that the 5-LOX protein was highly expressed in human HCC, HepG2 cells and rat HCC, but not in the normal liver tissues. 5-LOX mRNA expression in human and rat HCC was also significantly increased compared to normal liver tissues. Zileuton, a 5-LOX inhibitor, reduced the nodule incidence and the mean number of nodules per nodule-bearing liver in DEN-induced rats. Further study using TUNEL assay showed that zileuton treatment induced apoptosis in the liver as the result of inhibition on 5-LOX levels. This result is consistent with our observation of significantly higher apoptotic indices in rats treated with DEN/zileuton, which were significantly higher compared to those from the control groups. In addition, zileuton reduced cell viability and induced apoptosis in a concentration-and time-dependent manner as detected using HepG2 cells in our in vitro analysis. In conclusion, 5-LOX is expressed in HCC, and the inhibition of 5-LOX blocks the development of HCC via the induction of apoptosis in tumor cells.

Gene associated with retinoid-interferon-induced mortality (GRIM-19), an important subunit of mitochondrial complex I, has been identified as a tumor suppressor, and its reduced expression has been reported to be associated with tumorigenesis and metastasis. Autophagy has been proposed as a protective mechanism for cell survival under various stresses, including chemotherapy. However, it remains unknown whether GRIM-19 is linked to autophagy and chemotherapy resistance. Here, we showed that suppression of GRIM-19 by shRNA enhanced cell-type-dependent autophagy by activating extracellular regulated protein kinase (ERK) and hypoxia inducible factor-1a (HIF-1a) in a reactive oxygen species (ROS)-mediated manner, and thereby conferred resistance to paclitaxel. Besides, the antioxidant N-acetyl-L-cysteine (NAC) and autophagy inhibitor 3-MA could in part overcome this resistance. We also found that GRIM-19 expression was significantly correlated with clinical stage and grade in patients with cervical cancers. Taken together, our results indicated that GRIM-19 inhibition induced autophagy and chemotherapy resistance, which could affect prognosis of cervical cancers. Our study has identified new function of GRIM-19 and its underlying mechanism, and it will provide possible avenues for therapeutic targeting in cervical cancers.

The aim of the present study was to determine how Endostar inhibits tumor angiogenesis and increases radiation sensitivity when combined with radiotherapy. In vitro studies were conducted to analyze the expression levels of transforming growth factor-β1 (TGF-β1), hypoxia-inducible factor 1 (HIF-1α) and basic fibroblast growth factor (bFGF) in lung adenocarcinoma A549 cells, using the antiangiogenesis drug Endostar combined with radiotherapy. In addition, lung adenocarcinoma A549 cell apoptosis was detected via Hoechst staining. The combination of Endostar with radiotherapy was investigated and the results indicated that this combination significantly inhibited tumor cell proliferation and TGF-β1, HIF-1α and bFGF expression. Changes in gene expression were found to promote apoptosis, thus, enhancing the inhibition of tumor angiogenesis and ultimately inhibiting tumor cell growth, invasion and metastasis.

No abstract

Doxorubicin- (DOX-) related cardiac injury impairs the life quality of patients with cancer. This largely limited the clinical use of DOX. It is of great significance to find a novel strategy to reduce DOX-related cardiac injury. Oroxylin A (OA) has been identified to exert beneficial effects against inflammatory diseases and cancers. Here, we investigated whether OA could attenuate DOX-induced acute cardiotoxicity in mice. A single dose of DOX was used to induce acute cardiac injury in mice. To explore the protective effects, OA was administered to mice for ten days beginning from five days before DOX injection. The data in our study indicated that OA inhibited DOX-induced heart weight loss, reduction in cardiac function, and the elevation in myocardial injury markers. DOX injection resulted in increased oxidative damage, inflammation accumulation, and myocardial apoptosis in vivo and in vitro, and these pathological alterations were alleviated by treatment of OA. OA activated the sirtuin 1 (Sirt1) signaling pathway via the cAMP/protein kinase A, and its protective effects were blocked by Sirt1 deficiency. OA treatment did not affect the tumor-killing action of DOX in tumor-bearing mice. In conclusion, OA protected against DOX-related acute cardiac injury via the regulation of Sirt1.