Rat Becn1 (Beclin-1) ELISA Kit

Hepatocellular carcinoma (HCC) can be originated from various etiologies and is preceded mostly by cirrhosis. Unfortunately, there is no effective treatment due to its late prognosis. Alterations in autophagy have been reported during the development and progression of HCC. Autophagy allows for the maintenance of a positive energy balance and the proper functioning of organelles through the selective degradation of cellular components. It has been demonstrated that autophagy suppresses spontaneous tumorigenesis in the liver. Therefore, autophagy has become a therapeutic target for effective HCC therapies. We have previously demonstrated that the adenosine-derived compound, IFC-305, has a chemopreventive effect on HCC, in addition to maintaining mitochondrial function in a sequential model of cirrhosis-HCC. Thus, the aim of this work was to determine if IFC-305 has an effect on autophagy in the sequential model of cirrhosis-HCC induced by diethylnitrosamine or in vitro in the HCC cell line HepG2 and mouse embryonic fibroblasts. The results of this work showed that IFC-305 modifies the levels of the BECN1, p62/SQSTM1 and LC3-II proteins that play an important role in the autophagic process. In vivo, IFC-305 regulates the levels of the PINK1 and PARKIN proteins that specifically mark mitochondria for repair or degradation. In the HepG2 cell line, its effect was accompanied by a decrease in cell viability. Interestingly, in nontumoral cells the time to autophagy induction was different compared to the HepG2 cells. This study suggests that autophagy induction may be part of the mechanism by which IFC-305 maintains mitochondrial function, thereby facilitating the prevention and reversal of HCC.

Mitophagy is a highly specialized process to remove dysfunctional or superfluous mitochondria through the macroautophagy/autophagy pathway, aimed at protecting cells from the damage of disordered mitochondrial metabolism and apoptosis induction. PINK1, a neuroprotective protein mutated in autosomal recessive Parkinson disease, has been implicated in the activation of mitophagy by selectively accumulating on depolarized mitochondria, and promoting PARK2/Parkin translocation to them. While these steps have been characterized in depth, less is known about the process and site of autophagosome formation upon mitophagic stimuli. A previous study reported that, in starvation-induced autophagy, the proautophagic protein BECN1/Beclin1 (which we previously showed to interact with PINK1) relocalizes at specific regions of contact between the endoplasmic reticulum (ER) and mitochondria called mitochondria-associated membranes (MAM), from which the autophagosome originates. Here we show that, following mitophagic stimuli, autophagosomes also form at MAM; moreover, endogenous PINK1 and BECN1 were both found to relocalize at MAM, where they promoted the enhancement of ER-mitochondria contact sites and the formation of omegasomes, that represent autophagosome precursors. PARK2 was also enhanced at MAM following mitophagy induction. However, PINK1 silencing impaired BECN1 enrichment at MAM independently of PARK2, suggesting a novel role for PINK1 in regulating mitophagy. MAM have been recently implicated in many key cellular events. In this light, the observed prevalent localization of PINK1 at MAM may well explain other neuroprotective activities of this protein, such as modulation of mitochondrial calcium levels, mitochondrial dynamics, and apoptosis.