Apoptin Inhibits Glycolysis and Regulates Autophagy by Targeting Pyruvate Kinase M2 (PKM2) in Lung Cancer A549 Cells

BACKGROUND

Pyruvate kinase M2 (PKM2) is a key enzyme in aerobic glycolysis and plays an important role in tumor energy metabolism and tumor growth. Ad-apoptin, a recombinant oncolytic adenovirus, can stably express apoptin in tumor cells and selectively causes cell death in tumor cells.

OBJECTIVE

The relationship between the anti-tumor function of apoptin, including apoptosis and autophagy activation, and the energy metabolism of tumor cells has not been clarified.

METHODS

In this study, we used the A549 lung cancer cell line to analyze the mechanism of PKM2 involvement in apoptin-mediated cell death in tumor cells. PKM2 expression in lung cancer cells was detected by Western blot and qRT-PCR. In the PKM2 knockdown and over-expression experiments, A549 lung cancer cells were treated with Ad-apoptin, and cell viability was determined by the CCK-8 assay and crystal violet staining. Glycolysis was investigated using glucose consumption and lactate production experiments. Moreover, the effects of Ad-apoptin on autophagy and apoptosis were analyzed by immunofluorescence using the Annexin v-mCherry staining and by western blot for c-PARP, p62, and LC3-II proteins. Immunoprecipitation analysis was used to investigate the interaction between apoptin and PKM2. In addition, following PKM2 knockdown and overexpression, the expression levels of p-AMPK, p-mTOR, p-ULK1, and p-4E-BP1 proteins in Ad-apoptin treated tumor cells were analyzed by western blot to investigate the mechanism of apoptin effect on the energy metabolism of tumor cells. The in vivo antitumor mechanism of apoptin was analyzed by xenograft tumor inhibition experiment in nude mice and immunohistochemistry of tumors' tissue.

RESULTS

As a result, apoptin could target PKM2, inhibit glycolysis and cell proliferation in A549 cells, and promote autophagy and apoptosis in A549 cells by regulating the PKM2/AMPK/mTOR pathway.

CONCLUSION

This study confirmed the necessary role of Ad-apoptin in the energy metabolism of A549 cells.

Heterogeneity of Red Blood Cell Deformability Caused by Lipopolysaccharide Based on a Microfluidic Chip

AIM

Alterations in red blood cell deformability (RBC-df) provide important information for the diagnosis of various diseases.

INTRODUCTION

We evaluated individual differences of lipopolysaccharide (LPS)-induced oxidative damage of RBC-df and analyzed the correlation between RBC-df and biochemical parameters.

METHODS

A microfluidic chip was developed to detect inter-individual variability of different concentrations of LPS-induced oxidative damage of RBC-df in 9 healthy volunteers. The relationships between various biochemical indicators (Na+-K+-ATPase activity, lipid peroxide (LPO) content, glutathione peroxidase (GSH-PX) activity, catalase (CAT) activity, superoxide dismutase (SOD) activity, adenosine triphosphate (ATP) content, and hemoglobin (HB) content) and RBCs-df were investigated.

RESULTS

The obvious inter-individual variability of LPS-induced oxidative damage of RBC-df was revealed. The Na+-K+-ATPase activity, LPO content, GSH-PX activity, and CAT activity of RBCs showed significant correlations with RBC-df (P < 0.05).

CONCLUSION

Oxidative damage and energy metabolism are the critical factors of RBC-df impairment induced by LPS, and the individual dependence on RBC-df is an important indicator for the treatment of infection-associated sepsis since antibiotics can kill pathogenic bacteria, which results in the release of LPS from the cell wall.

Association of Val16Ala Polymorphism of Manganese Superoxide Dismutase (MnSOD) with Food Intake and Cardiometabolic Risk Factors in the Elderly in Primary Care in Porto Alegre

BACKGROUND

The aging process causes physiological changes on its own. The combination of an unhealthy lifestyle with the presence of genetic polymorphisms, such as the Val16Ala of the antioxidant enzyme manganese-dependent superoxide dismutase (MnSOD) may contribute to a greater occurrence of cardiometabolic risk factors.

OBJECTIVE

This study aimed to verify the association of Val16Ala-MnSOD polymorphism with food intake, caloric expenditure, and cardiometabolic risk factors in the elderly.

METHODS

A cross-sectional study with a sample size of 270 elderly individuals assisted in primary health care in the city of Porto Alegre, RS, Brazil. Val16Ala polymorphism, glucose, lipid profile, insulin, HOMA-IR, blood pressure, waist circumference, PCR-us, IL-6, food consumption, and caloric expenditure were evaluated.

RESULTS

The average age of the elderly was 68.6 ± 7.6 years. There were statistically significant differences regarding the consumption of two or more servings of fruits and vegetables daily between the elderly VV versus AV (P=0.017). There were also statistically significant differences regarding the consumption of two or more daily servings of legumes and eggs between the elderly AA versus VV (P=0.002). The median of insulin was higher in the elderly AA versus AV (P=0.025) and the median of HOMA-IR was higher in the elderly VV versus AV (P=0.029). AA elderly individuals had higher means of high-density lipoprotein (HDL-c) compared to AV (P=0.029).

CONCLUSION

The results suggest that Val16Ala -MnSOD polymorphism is associated with the consumption of fruits, vegetables, legumes, and eggs, as well as with cardiometabolic risk factors in the elderly.

Quantitative Proteomic Map of the Trypanosomatid Strigomonas culicis: The Biological Contribution of its Endosymbiotic Bacterium

Strigomonas culicis is a kinetoplastid parasite of insects that maintains a mutualistic association with an intracellular symbiotic bacterium, which is highly integrated into the protist metabolism: it furnishes essential compounds and divides in synchrony with the eukaryotic nucleus. The protist, conversely, can be cured of the endosymbiont, producing an aposymbiotic cell line, which presents a diminished ability to colonize the insect host. This obligatory association can represent an intermediate step of the evolution towards the formation of an organelle, therefore representing an interesting model to understand the symbiogenesis theory. Here, we used shotgun proteomics to compare the S. culicis endosymbiont-containing and aposymbiotic strains, revealing a total of 11,305 peptides, and up to 2,213 proteins (2,029 and 1,452 for wild type and aposymbiotic, respectively). Gene ontology associated to comparative analysis between both strains revealed that the biological processes most affected by the elimination of the symbiont were the amino acid synthesis, as well as protein synthesis and folding. This large-scale comparison of the protein expression in S. culicis marks a step forward in the comprehension of the role of endosymbiotic bacteria in monoxenous trypanosomatid biology, particularly because trypanosomatids expression is mostly post-transcriptionally regulated.

Alternative Type II NAD(P)H Dehydrogenases in the Mitochondria of Protists and Fungi

Plants, fungi, and some protists possess a more branched electron transport chain in their mitochondria compared to canonical one. In these organisms, the electron transport chain contains several rotenone-insensitive NAD(P)H dehydrogenases. Some are located on the outer surface, and others are located on the inner surface of the inner mitochondrial membrane. The putative role of these enzymes still remains elusive, but they may prevent the overreduction of the electron transport chain components and decrease the production of reaction oxygen species as a consequence. The last two decades resulted in the discovery of alternative rotenone-insensitive NAD(P)H dehydrogenases present in representatives of fungi and protozoa. The aim of this review is to gather and focus on current information concerning molecular and functional properties, regulation, and the physiological role of fungal and protozoan alternative NAD(P)H dehydrogenases.