valinomycin and Liver-Neoplasms

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).\ \ This article has been retracted at the request of the corresponding author.\ \ It has been found that Fig 2B contains manipulated components, and Fig 5A partially overlaps with Fig 6 of a published paper authored by Mirza Muhammad Faran Ashraf Baig, et, al., The effective transfection of a low dose of negatively charged drug-loaded DNA-nanocarriers into cancer cells via scavenger receptors, J. Pharm. Anal. 11 (2021) 174-182, https://doi.org/10.1016/j.jpha.2020.10.003. The corresponding author indicated that they cannot guarantee the integrity of the images in the manuscript, as well as the conclusions of the paper. As a result, the Editor-in-Chief has decided to retract the paper.\ \ The corresponding author deeply regrets the circumstances and apologizes to the scientific community for not having detected this prior to publication.

Topics: Apoptosis; Cell Line; Humans; Liposomes; Liver Neoplasms; Valinomycin

The present study was undertaken to evaluate, in the HepG2 human hepatoma cell line, the in vitro cytotoxic, genotoxic, and apoptotic activities of estragole (1), contained in the essential oil of Foeniculum vulgare (fennel) and suspected to induce hepatic tumors in susceptible strains of mice. Toward this end, an MTT cytotoxicity assay, a trypan blue dye exclusion test, a double-staining (acridine orange and DAPI) fluorescence viability assay, a single-cell microgel-electrophoresis (comet) assay, a mitochondrial membrane potential (Δψm) assay, and a DNA fragmentation analysis were conducted. In terms of potential genotoxic effects, the comet assay indicated that estragole (1) was not able to induce DNA damage nor apoptosis under the experimental conditions used.

Topics: Acridine Orange; Allylbenzene Derivatives; Animals; Anisoles; Apoptosis; Carcinoma, Hepatocellular; DNA Damage; DNA Fragmentation; Electrophoresis; Fluorescent Dyes; Foeniculum; Hep G2 Cells; Humans; Indoles; Liver Neoplasms; Membrane Potential, Mitochondrial; Mice; Molecular Structure; Oils, Volatile

Valinomycin is a potassium ionophore, and is well known to cause the collapse of the mitochondrial membrane potential. It has been reported that loss of mitochondrial membrane potential is observed in the early stages of apoptosis induced by various agents. Thus, the effects of valinomycin on tumor cells were examined. Valinomycin induced uncoupling of respiration and depolarization of isolated mitochondria. Depolarization of intact mitochondria in AH-130 rat ascites hepatoma cells was also induced by valinomycin. Valinomycin induced apoptosis revealing the typical apoptotic characteristics such as fragmentation and ladder formation of DNA, shrinkage of cells, and formation of pycnotic nucleus. There was a correlation between the depolarization of mitochondria and DNA fragmentation. After depolarization of mitochondria, the activity of caspase-3-like protease but not caspase-1-like protease increased markedly. In contrast, this apoptosis did not involve the release of reactive oxygen species from mitochondria, increase in intracellular calcium concentration, or protein synthesis. In addition, anti-apoptotic members of the Bcl-2 family (Bcl-xL and Bcl-2) were not correlated with apoptosis. These results indicate that valinomycin might induce apoptosis through degradation of the mitochondrial membrane potential. Taken together, these observations suggest that there may be a mechanism that transmits the signal from mitochondrial depolarization to subsequent apoptosis execution steps.

Topics: Animals; Apoptosis; Ascites; bcl-X Protein; Carcinoma, Hepatocellular; Caspase 1; Caspase 3; Caspases; Cysteine Endopeptidases; DNA Fragmentation; DNA, Neoplasm; Ionophores; Liver Neoplasms; Male; Membrane Potentials; Mitochondria; Oxygen Consumption; Proto-Oncogene Proteins c-bcl-2; Rats; Tumor Cells, Cultured; Valinomycin

One of the body's natural defense mechanisms against tumor cells is lysis of the invading cell by cytotoxic T-cells and natural killer (NK) cells. Five human hepatocellular carcinoma cell lines were found to have different sensitivities to killing by peripheral blood monocytes in a 51Cr release assay. This killing was demonstrated to be due to NK cell lysis. Electrical recording measurements of the membrane potentials of these five cell lines showed different values for each line, all below values reported for normal hepatocytes. Correlation between mean cell membrane potential, and sensitivity to NK lysis, revealed an inverse relationship. In this study we demonstrate that the lower the mean membrane potential of a human hepatocellular carcinoma cell line, the more sensitive it is to NK cell cytolysis. Cell surface positive potential did not correlate with NK cytolysis and only a weak correlation was found between cell membrane negative potential and cell surface positive potential between cell lines.

Topics: Carcinoma, Hepatocellular; Cytotoxicity, Immunologic; Humans; Interferon Type I; Killer Cells, Natural; Liver Neoplasms; Membrane Potentials; Potassium Chloride; Recombinant Proteins; Tumor Cells, Cultured; Valinomycin

The uncoupler-stimulated mitochondrial ATPase of four human tumors, mouse kidney, brain and fetal liver exhibited a characteristic behavior when preincubated with the H+-conducting uncouplers, dinitrophenol, CCCP, S-13 and gramicidin. The ATPase activity was considerably lower with preincubation than without. Preincubation with valinomycin (+ K+), on the other hand, did not result in a significant decrease of the ATPase activity. These results may be contrasted with those obtained with liver or heart mitochondria, the ATPase activity of which did not suffer any loss when preincubated with dinitrophenol. The effect of preincubation with dinitrophenol on the tumor mitochondria could not be accounted for by dinitrophenol-induced Mg2+ efflux, since the differential effects of dinitrophenol and valinomycin (+ K+) remained even when ATPase activity was determined in presence of Mg2+. Small amounts of ATP and ADP in the preincubation mixture containing dinitrophenol protected against the decay of the ATPase activity, implicating the exchangeable adenine nucleotides in the tumor mitochondria. In a model system where liver mitochondria were depleted of their adenine nucleotides, a lower ATPase activity was indeed obtained. However, direct determination of the concentrations of adenine nucleotides in dinitrophenol- and valinomycin-treated tumor mitochondria revealed only slight differences.

Topics: 2,4-Dinitrophenol; Adenosine Triphosphatases; Animals; Astrocytoma; Brain; Carcinoma, Hepatocellular; Carcinoma, Small Cell; Cell Line; Dinitrophenols; Humans; Kidney; Kinetics; Liver; Liver Neoplasms; Lung Neoplasms; Melanoma; Mice; Mitochondria; Myocardium; Neoplasms; Uncoupling Agents; Valinomycin

The cholesterol to phospholipid ratio in mitochondria from hepatomas AH-130, 3924A and 5123 is higher than in the particles isolated from adult or fetal rat livers. Nearly all the cholesterol of hepatoma mitochondria is located in membranes. As in liver mitochondria, in the particles isolated from hepatoma AH-130 there is more cholesterol in the outer than in the inner membrane. In mitochondria from cholesterol-enriched liver and hepatomas, there occurs a decrease in extent of hypoosmotic and phosphate-induced swelling and a decrease of conformational changes linked to energy states. The phenomenon is more marked in particles which exhibit higher cholesterol to phospholipid ratios. A statistically significant negative correlation exists between the cholesterol to phospholipid ratio and extent of volume or conformational changes. No significant modifications of these parameters were found in fetal liver mitochondria. Cholesterol content does not influence K+ uptake by cholesterol-enriched or hepatoma mitochondria. Nor does cholesterol content affect the respiratory increment related to this uptake. As a consequence of K+ uptake, total mitochondrial water exchangeable with tritiated water rises 20% while sucrose-impermeable water rises 42-48% in both adult rat liver and hepatoma AH-130 mitochondria. Absorbance changes linked to ion uptake do not correspond merely to variations in mitochondrial water content. Water content is apparently not influenced by the cholesterol to phospholipid ratio. However, the ratio is significantly correlated to both extent and initial rate of absorbance decrease of mitochondrial suspensions during K+ uptake. The higher the ratio, the lower the extent and initial rate of absorbance decrease.

Topics: Animals; Carcinoma, Hepatocellular; Cholesterol; Cytochrome Reductases; Diet; Female; Fetus; Liver Neoplasms; Magnesium; Malate Dehydrogenase; Male; Membranes; Mitochondria, Liver; Mitochondrial Swelling; Neoplasms, Experimental; Osmolar Concentration; Oxygen Consumption; Phosphates; Potassium; Rats; Rats, Inbred ACI; Valinomycin; Water