The role of cellular oxidative stress in regulating glycolysis energy metabolism in hepatoma cells

<p>Abstract</p> <p>Background</p> <p>The Warburg effect has been found in a wide spectrum of human cancers, however the underlying mechanisms are still unclear. This study aims to explore the role of cellular oxidative stress in relation to glycolysis and the Warburg effect in hepatoma cells.</p> <p>Methods</p> <p>Various cell lines combining environmental hypoxia was used as an in vitro model to mimic tumor microenvironment in vivo. Superoxide dismutases (SOD) and xanthine oxidase (XO) gene transfection were used to produce various cellular redox levels. 2',7'-dichlorofluorescin (DCF) fluorescence and ESR spectrum were used to detect cellular reactive oxygen species (ROS).</p> <p>Results</p> <p>We found that endogenous or exogenous interference with the cellular oxidative stress can sensitively regulate glycolysis and the Warburg effect in hepatoma cells. Hepatoma cells displayed a high level of free radicals compared to immortalized normal hepatocyte cells. Increasing the level of ROS stress in hepatoma cells can directly upregulate HIF-1 and activate glycolysis without requirement of a hypoxic condition. This explains the mechanism whereby aerobic glycolysis, i.e. the Warburg effect arises. Either endogenously upregulating SOD or exogenously administration with antioxidant can, through downregulating ROS level, effectively regulate energy pathways in hepatoma cells and can inhibit the growth of tumor cells and xenograft tumors.</p> <p>Conclusion</p> <p>This study suggests that the Warburg effect was related to an inherently high level of cellular ROS and HIF-1. Hepatoma cells adaptation to hypoxia for survival and rapid growth exploits oxidative stress ectopically activated glycolysis to compensate the energy supply. This specific mechanism in which tumor cells through cellular oxidative stress activate glycolysis to meet their energy metabolism requirement could be exploited to selectively kill tumor cells.</p

Corporate innovation and environmental investment:The moderating role of institutional environment

Corporate environmental investment helps improve corporate environmental performance, which, therefore, is an effective micro-level solution to mitigate environmental concerns generated by corporate excessive resource exploitation and energy use. Using Chinese listed firms within environment-related industries over the period 2011–2018 as the research setting, this study applies the panel data model to investigate the impact of corporate innovation on environmental investment, as well as the moderating effects of institutional factors. The results show that corporate innovation significantly improves firms' environmental investment with 1% Research & Development (R&D) investment ratio increase generating 2326 CNY (around 351 USD at 2018 exchange rate) increase in environmental investment; the moderating effect of environment policy is positive and significant while the moderating effect of internationalisation level is not significant, indicating that current environment policy implementation helps to strengthen the positive impact of corporate innovation on environmental investment while the role of internationalisation level in this nexus is not observed. From a micro-level perspective, the findings of this study shed light on mitigating environmental concerns through enhancing corporate innovation, and provide evidence that China's corporate internationalisation process awaits more regulatory controls

Fabrication of multianalyte CeO2 nanograin electrolyte–insulator–semiconductor biosensors by using CF4 plasma treatment

Multianalyte CeO2 biosensors have been demonstrated to detect pH, glucose, and urine concentrations. To enhance the multianalyte sensing capability of these biosensors, CF4 plasma treatment was applied to create nanograin structures on the CeO2 membrane surface and thereby increase the contact surface area. Multiple material analyses indicated that crystallization or grainization caused by the incorporation of flourine atoms during plasma treatment might be related to the formation of the nanograins. Because of the changes in surface morphology and crystalline structures, the multianalyte sensing performance was considerably enhanced. Multianalyte CeO2 nanograin electrolyte–insulator–semiconductor biosensors exhibit potential for use in future biomedical sensing device applications

Polarization-based probabilistic discriminative model for quantitative characterization of cancer cells

We propose a polarization-based probabilistic discriminative model for deriving a set of new sigmoid-transformed polarimetry feature parameters, which not only enables accurate and quantitative characterization of cancer cells at pixel level, but also accomplish the task with a simple and stable model. By taking advantages of polarization imaging techniques, these parameters enable a low-magnification and wide-field imaging system to separate the types of cells into more specific categories that previously were distinctive under high magnification. Instead of blindly choosing the model, the L0 regularization method is used to obtain the simplified and stable polarimetry feature parameter. We demonstrate the model viability by using the pathological tissues of breast cancer and liver cancer, in each of which there are two derived parameters that can characterize the cells and cancer cells respectively with satisfactory accuracy and sensitivity. The stability of the final model opens the possibility for physical interpretation and analysis. This technique may bypass the typically labor-intensive and subjective tumor evaluating system, and could be used as a blueprint for an objective and automated procedure for cancer cell screening

Frequency-Synthesized Approach to High-Power Attosecond Pulse Generation and Applications: Applications

In part I of this work, we present the design, construction and diagnostics of a new scheme of generating high-power attosecond pulses and arbitrary waveforms by multicolor synthesis. In this chapter, we demonstrate selected applications of this novel source, such as coherently controlled harmonic generation as well as phase-sensitive two-color ablation of copper and stainless steel by this multicolor laser system

Frequency-Synthesized Approach to High-Power Attosecond Pulse Generation and Applications: Generation and Diagnostics

We present a new scheme of generating high-power attosecond pulses and arbitrary waveform synthesis by multicolor synthesis. The full bandwidth of the multicolor laser system extends more than two-octaves and reaches 37,600 cm−1 which can be used to generate sub-single-cycle (∼0.37 cycle) sub-femtosecond (360 attosecond) pulses with carrier-envelope phase (CEP) control. The results show a promising approach for generation of relatively high-power attosecond pulses in the optical region. In this chapter, the design and diagnostics of the laser system are described. In part 2 of this work (the following chapter), we demonstrate selected applications of this novel source, such as coherently controlled harmonic generation as well as phase-sensitive 2-color ablation of copper and stainless steel by this multi-color laser system