Tissue factor promotes HCC carcinogenesis by inhibiting BCL2-dependent autophagy.

INTRODUCTION: Tissue factor (TF) is an important predictor for poor prognosis of Hepatocellular carcinoma (HCC). TF can also upregulate the expression of BCL2, which is a key inhibitor of autophagy responses. This study aims to explore the role of BCL2-dependent autophagy in TF-regulated HCC carcinogenesis. METHODS: In this study, we explored the roles of TF in HCC using gene overexpression and silencing assays. Besides, we further identified the significance of BCL2-Beclin1-autophagy signaling on TF-regulated HCC tumorigenesis by combining TF silencing with pharmacological autophagy inhibitor (3-MA). RESULTS: The experimental data showed that the overexpressed TF promoted BCL2 protein expression and inhibited the autophagy activity (shown as LC3 conversion rate, p62 expression and autophagosomes) while maintaining the survival in HCC cells. In contrast, the silent TF showed the completely opposite results. Furthermore, TF knockdown promoted the dissociation of Beclin1 from BCL2-Beclin1 complex. In addition, the enhanced autophagy and inhibited survival by TF knockdown could be reversed by autophagy inhibition with 3-MA or spautin-1 (Beclin1 specific inhibitor) in HCC cells. Xenografts assays also showed that TF-silencing HCC cells had stronger tumorigenicity in vivo, which was recovered by spautin-1 administration. CONCLUSIONS: TF inhibits autophagy-related death by enhancing BCL2 expression, whereby promoting HCC tumorigenesis.

Evaluation of the interaction between anti-apoptotic Bcl-2 protein family mRNA expression and autophagy gene Bcl-1 expression in Egyptian SLE patients.

OBJECTIVES: Autophagy is a complex cellular process that maintains homeostasis in systemic lupus erythematosus. Abnormally high expression of Bcl-2 was observed in B and T lymphocytes in the peripheral blood in SLE patients. These may be responsible for the survival of self-reactive lymphocytes and the development of lupus, and the study aims at evaluating interaction between apoptosis and autophagy in Egyptian lupus patients. METHODS: Sixty patients with SLE were diagnosed by fulfilling the Systemic Lupus International Collaborating Clinics (SLICC) classification criteria for SLE and sixty healthy age and sex matched control. All patients were subjected to full medical history and clinical examination. Activity was assessed using SLEDAI-2K score. Gene expression of Beclin-1, Bcl-2-L2, and Bcl-2 was measured. RESULTS: The study revealed that the expression of anti-apoptotic Bcl-2 and Bcl-2-L2 was significantly higher in SLE patients than control subjects, as well as the major apoptotic agent (Beclin-1) mRNA, p = 0.03, < 0.001 and 0.02, respectively. The apoptotic Beclin-1 mRNA was positively correlated with SLE disease severity index, r = 0.25; p = 0.0.4; therefore, our results showed that expression of the Beclin-1 was significantly higher in SLE patients than control (p < 0.02). CONCLUSION: Our results showed that expression of the Beclin 1 were significantly higher in SLE patients than control (p < 0.02).

Targeting autophagy-related protein kinases for potential therapeutic purpose.

Autophagy, defined as a scavenging process of protein aggregates and damaged organelles mediated by lysosomes, plays a significant role in the quality control of macromolecules and organelles. Since protein kinases are integral to the autophagy process, it is critically important to understand the role of kinases in autophagic regulation. At present, intervention of autophagic processes by small-molecule modulators targeting specific kinases has becoming a reasonable and prevalent strategy for treating several varieties of human disease, especially cancer. In this review, we describe the role of some autophagy-related kinase targets and kinase-mediated phosphorylation mechanisms in autophagy regulation. We also summarize the small-molecule kinase inhibitors/activators of these targets, highlighting the opportunities of these new therapeutic agents.

Neuroprotective effects of rapamycin on spinal cord injury in rats by increasing autophagy and Akt signaling.

Rapamycin treatment has been shown to increase autophagy activity and activate Akt phosphorylation, suppressing apoptosis in several models of ischemia reperfusion injury. However, little has been studied on the neuroprotective effects on spinal cord injury by activating Akt phosphorylation. We hypothesized that both effects of rapamycin, the increased autophagy activity and Akt signaling, would contribute to its neuroprotective properties. In this study, a compressive spinal cord injury model of rat was created by an aneurysm clip with a 30 g closing force. Rat models were intraperitoneally injected with rapamycin 1 mg/kg, followed by autophagy inhibitor 3-methyladenine 2.5 mg/kg and Akt inhibitor IV 1 µg/kg. Western blot assay, immunofluorescence staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay were used to observe the expression of neuronal autophagy molecule Beclin 1, apoptosis-related molecules Bcl-2, Bax, cytochrome c, caspase-3 and Akt signaling. Our results demonstrated that rapamycin inhibited the expression of mTOR in injured spinal cord tissue and up-regulated the expression of Beclin 1 and phosphorylated-Akt. Rapamycin prevented the decrease of bcl-2 expression in injured spinal cord tissue, reduced Bax, cytochrome c and caspase-3 expression levels and reduced the number of apoptotic neurons in injured spinal cord tissue 24 hours after spinal cord injury. 3-Methyladenine and Akt inhibitor IV intervention suppressed the expression of Beclin-1 and phosphorylated-Akt in injured spinal cord tissue and reduced the protective effect of rapamycin on apoptotic neurons. The above results indicate that the neuroprotective effect of rapamycin on spinal cord injury rats can be achieved by activating autophagy and the Akt signaling pathway.

Targeting autophagy as a potential therapeutic approach for melanoma therapy.

Melanoma, occurring as a rapidly progressive skin cancer, is resistant to current chemo- and radiotherapy, especially after metastases to distant organs has taken place. Most chemotherapeutic drugs exert their cytotoxic effect by inducing apoptosis, which, however, is often deficient in cancer cells. Thus, it is appropriate to attempt the targeting of alternative pathways, which regulate cellular viability. Recent studies of autophagy, a well-conserved cellular catabolic process, promise to improve the therapeutic outcome in melanoma patients. Although a dual role for autophagy in cancer therapy has been reported, both protecting against and promoting cell death, the potential for using autophagy in cancer therapy seems to be promising. Here, we review the recent literature on the role of autophagy in melanoma with respect to the expression of autophagic markers, the involvement of autophagy in chemo- and immunotherapy, as well as the role of autophagy in hypoxia and altered metabolic pathways employed for melanoma therapy.