Inhibition of autophagic sequestration and endogenous protein degradation in isolated rat hepatocytes by methylated adenosine derivatives

Kovács, Atilla; Molnár, Katalin; Seglen, Per Ottar

doi:10.1016/0014-5793(81)80600-x

Cited by 22 publications

(11 citation statements)

References 10 publications

(1 reference statement)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Beclin-1 binds to different molecules to form a complex that regulates the formation and maturation of autophagosomes. When autophagolysosomes form, Beclin-1 is degraded by proteolytic enzymes of the lysosomes (24). The present study indicated that bufalin upregulated the protein expression of LC3-II and Beclin-1, as well as downregulated the expression of p62 in HCC-LM3 cells.…”

Section: Discussionsupporting

confidence: 51%

The biological role of autophagy in regulating and controlling the proliferation of liver cancer cells induced by bufalin

et al. 2018

View full text Add to dashboard Cite

Autophagy is an important mechanism which regulates the processes of cell growth and death. The biological role of autophagy in regulating and controlling the proliferation of liver cancer cells by bufalin remains unknown. In the present study we investigated the effect of bufalin on autophagy of liver cancer cells. The growth inhibition and autophagy of liver cancer cells were detected using acridine orange fluorescence staining, flow cytometry and transmission electron microscopy. Combined with autophagy inhibitors (3‑MA and CQ), CCK8 staining and western blot analysis were used to detect the effect of bufalin on the proliferation and autophagy‑related protein expression in HCC‑LM3 cells at the indicated time‑points. Results indicated that combined with autophagy inhibitors 3‑MA and CQ, the inhibitive effect of bufalin on the proliferation of HCC‑LM3 cells was significantly enhanced. When combined with autophagy inhibitors 3‑MA or CQ, bufalin significantly reduced the autophagosome and acidic vesicles in HCC‑LM3 cells. When combined with autophagy inhibitors 3‑MA and/or CQ for 12 h, bufalin significantly inhibited the expression of LC3‑I and Beclin‑1 in HCC‑LM3 cells, and upregulated the expression of LC3‑II and P62 in HCC‑LM3 cells. When combined with autophagy inhibitors 3‑MA and/or CQ for 24 h, bufalin significantly inhibited the LC3‑II expression in HCC‑LM3 cells, and upregulated the LC3‑I, P62 and Beclin‑1 expression in HCC‑LM3 cells. When combined with autophagy inhibitors 3‑MA and/or CQ for 48 h, bufalin significantly inhibited the expression of LC3‑II and Beclin‑1 in HCC‑LM3 cells, and upregulated the expression of LC3‑I and P62 in HCC‑LM3 cells. These findings indicated that bufalin induced cell autophagy and inhibited proliferation of liver cancer cells by influencing the expression of autophagy related proteins including LC3‑I, LC3‑II, P62 and Beclin‑1 in liver cancer cells. The autophagic state of liver cancer cells affected the inhibitory effect of bufalin on the proliferation of liver cancer cells.

show abstract

Section: Discussionsupporting

confidence: 51%

The biological role of autophagy in regulating and controlling the proliferation of liver cancer cells induced by bufalin

et al. 2018

View full text Add to dashboard Cite

show abstract

“…The autophagy-suppressive effects of 3MA and some other methylaminopurines and mercaptopurines 61,100 were originally discovered on the basis of a side effect of the protein synthesis inhibitor, puromycin, on protein degradation. 101,102 As discussed above, high concentrations of 3MA (5-10 mM) will block autophagic sequestration completely in all mammalian cell types studied (Fig. 7), with litte or no effect on other endogenous degradation mechanisms or on basic cellular functions such as energy metabolism, protein synthesis or cellular viability.…”

Section: Inhibition Of Autophagymentioning

confidence: 98%

Methods for Monitoring Autophagy from Yeast to Human

2007

Self Cite

View full text Add to dashboard Cite

The increasing interest in autophagy in a wide range of organisms, accompanied by an ever-growing influx of researchers into this field, necessitates a good understanding of the methodologies available to monitor this process. In this review we discuss current approaches that can be used to follow the overall process of autophagy, as well as individual steps, from yeast to human. The majority of the review considers methods that apply to macroautophagy; however, we also consider alternative types of degradation including chaperone-mediated autophagy and microautophagy. This information is meant to provide a resource for newcomers as well as a stimulus for experienced researchers who may be prompted to develop additional assays to examine autophagy-related pathways.

show abstract

“…More detailed studies on this point are needed; furthermore there seems to be no analogous information on the transfer of fluid contents of endocytic vesicles to lysosomes in the presence of amines. As suggested by Kovacs et al (1981), fusion of other substratebearing vesicles (such as autophagic vesicles, derived intracellularly) with lysosomes may frequently be inhibited by amines.…”

Section: Effects On Intracellular Fusion Eventsmentioning

confidence: 97%

Effects of exogenous amines on mammalian cells, with particular reference to membrane flow

Dean¹,

Jessup²,

Roberts³

1984

Biochemical Journal

247

115

View full text Add to dashboard Cite

We have reviewed the evidence that amines accumulate in intracellular vesicles of low pH, such as lysosomes and endosomes. There is consequent elevation of intravesicular pH, and inhibition of receptor-ligand dissociation often results from this pH change. We have argued that the capacity for fusion of such vesicles is also reduced by the high pH. We suggest that the variety of effects of amines on membrane flow and macromolecular transport we describe are at least partly due to such reduced fusion (Figs. 1 and 2). We propose that an internal low pH may facilitate heterologous vesicle-vesicle and vesicle-plasma membrane fusion. There is some evidence that clathrin can accelerate phospholipid vesicle fusion in vitro at low pH (Blumenthal et al., 1983) but no direct evidence on the role of intravesicular pH. This idea is consistent not only with the preceding discussion, but also with the fact that the intracellular membrane-bound compartments least involved in fusion events (e.g. mitochondria) are of neutral or alkaline internal pH. Membrane fusion is certainly required for the formation of vesicles at the periphery of the Golgi apparatus, and possibly earlier in the transport and processing of biosynthetic products in the Golgi (Bergeron et al., 1982). Thus the accumulation of amines in the Golgi may be responsible for several effects on the flow of macromolecules along their translocation pathways. The status of the plasma membrane in this view is complex. It might be argued that the pH dictating the fusion step in endocytosis is that of the extracellular fluid, in which case the inhibitory effects of amines on this process are not explained. However, the rapidity of acidification of the newly formed endocytic vesicles allows the possibility that plasma membrane invaginations might temporarily sequester areas which are of lower pH than that of the bulk extracellular fluid even before fusion, since the proton pumping enzyme(s) are probably present on the plasma membrane. Were this the case, then an acid pH could again be a factor determining membrane fusion at the plasma membrane. The inhibition of endocytosis by weak bases thus may again reflect elevation of pH in a sequestered compartment. From the data on the dependence of response on the concentration of amines, we anticipate that most responses involving membrane flow will be biphasic, with inhibitory effects at low amine concentration, giving way to stimulatory ones at higher concentrations. We suggest that the reported dichotomy between different amines in intracellular membrane fusion systems (D'Arcy Hart, 1982) may result from this concentration dependence.(ABSTRACT TRUNCATED AT 400 WORDS)

show abstract

Inhibition of autophagic sequestration and endogenous protein degradation in isolated rat hepatocytes by methylated adenosine derivatives

Cited by 22 publications

References 10 publications

The biological role of autophagy in regulating and controlling the proliferation of liver cancer cells induced by bufalin

The biological role of autophagy in regulating and controlling the proliferation of liver cancer cells induced by bufalin

Methods for Monitoring Autophagy from Yeast to Human

Effects of exogenous amines on mammalian cells, with particular reference to membrane flow

Contact Info

Product

Resources

About