Monitoring the mechanism of anti-cancer agents to inhibit colorectal cancer cell proliferation: Enzymatic biosensing of glucose combined with molecular docking

Enzyme-Free In-Situ Electrochemical Measurement Using a Porous Membrane Electrode for Glucose Transport into Cell Spheroids

Microphysiological systems have attracted attention because of their use in drug screening. However, it is challenging to measure cell functions in real time using a device. In this study, we developed a cell culture device using a porous membrane electrode for in situ electrochemical glucose measurements for cell analysis. First, a porous membrane electrode was fabricated and electrochemically evaluated for enzyme-free glucose measurement. Subsequently, the glucose uptake of MCF-7 spheroids was evaluated using living spheroids, fixed spheroids, supernatants, and glucose transporter inhibitor-treated spheroids. Conventionally, the direct optical measurement of glucose uptake requires fluorescence-labeled glucose derivatives. In addition, the glucose uptake can be evaluated by measuring the glucose concentration in the medium by optical or electrochemical measurements. However, glucose needs to be consumed in the entire cell culture medium, which needs a long culture time. In contrast, our system can measure glucose in approximately 5 min without any labels because of in situ electrochemical measurements. This system can be used for in situ measurements in in vitro cell culture systems, including organ-on-a-chip for drug screening.

Mitochondrial dysfunction significantly contributes to the sensitivity of tumor cells to anoikis and their metastatic potential

It is well-known that the survival of metastatic cells during their dissemination plays an important role in metastasis. However, does this mean that the final result of the metastatic cascade (the volume of metastatic damage to distant organs and tissues) depends on, or at least correlates with, the degree of resistance to anoikis (distinctive hallmarks of metastatic cells)? This question remains open.The aim of the work was to study in vitro the changes in the survival rates, proliferative activity, oxidative stress, and glycolysis intensity during three days of anchorage-dependent and anchorage-independent growth of two Lewis lung carcinoma cell lines (LLC and LLC/R9) and compare these changes with the status of mitochondria and metastatic potential of the cells in vivo.

Methods

The number and volume of lung metastases were estimated for each cell line after intramuscular inoculation of the cells in C57Bl/6 mice. For the in vitro study, the cells were seeded on Petri dishes pretreated with poly-HEMA or untreated dishes and then allowed to grow for 3 days. Cell viability, cell cycle progression, the level of reactive oxygen species (ROS), glucose consumption and lactate production rates were investigated daily in both growth conditions. An electron microscopy study of intracellular structures was carried out.

Results

The study showed (as far as we know for the first time) a correlation between the metastatic potential of cells (determined in vivo) and their sensitivity to anoikis (assessed in vitro). The transition of LLC/R9 cells with an inherently defective mitochondrial system to the conditions of anchorage-independent growth was characterized by a decrease in survival, a slowdown in growth rates, an increase in both glucose consumption rate and intracellular ROS levels and manyfold lower metastatic potential, compared to highly metastatic LLC cells with the normal mitochondrial system.

Tumor diagnosis using carbon-based quantum dots: Detection based on the hallmarks of cancer

Carbon-based quantum dots (CQDs) have been shown to have promising application value in tumor diagnosis. Their use, however, is severely hindered by the complicated nature of the nanostructures in the CQDs. Furthermore, it seems impossible to formulate the mechanisms involved using the inadequate theoretical frameworks that are currently available for CQDs. In this review, we re-consider the structure-property relationships of CQDs and summarize the current state of development of CQDs-based tumor diagnosis based on biological theories that are fully developed. The advantages and deficiencies of recent research on CQDs-based tumor diagnosis are thus explained in terms of the manifestation of nine essential changes in cell physiology. This review makes significant progress in addressing related problems encountered with other nanomaterials.

Better biocompatibility of nitrogen-doped graphene compared with graphene oxide by reducing cell autophagic flux blockage and cell apoptosis

Nitrogen-doped graphene (C2 N), a novel graphene-based materials, has been proposed as a potential alternative to graphene oxide (GO) in biomedical applications. However, due to the challenges in synthesizing C2 N, reports in the biomedical field are currently rare. Here, we have modified the reported procedure and successfully synthesized C2 N nanoparticles at 120°C, which we refer to as C2 N-120. The toxicity and biocompatibility of GO and C2 N-120 were evaluated using a mouse model injected with GO/C2 N-120 via the tail vein, as well as cell models treated with GO/C2 N-120. In vivo studies revealed that GO/C2 N-120 showed similar distribution patterns after tail vein injection. The liver, spleen, and lung are the major nanoparticle uptake organs of GO and C2 N-120. However, GO deposition in the major nanoparticle uptake organs was more significant than that of C2 N-120. In addition, GO deposition caused structural abnormalities, increased apoptotic cells, and enhanced macrophage infiltration whereas C2 N-120 exhibited fewer adverse effects. In vitro experiments were conducted using different cell lines treated with GO/C2 N-120. Unlike GO which induced mitochondrial damage, oxidative stress, inflammatory response, autophagic flux blockage and cell apoptosis, C2 N-120 showed lower cytotoxicity in cell models. Our data demonstrated that C2 N-120 exhibits higher biocompatibility than GO, both in vivo and in vitro, suggesting its potential for biomedical application in the future.