Human mesenchymal stem cells increase LLC metastasis and stimulate or decelerate tumor development depending on injection method and cell amount.

Mesenchymal stem cells (MSCs) being injected into the body can stimulate or decelerate carcinogenesis. Here, the direction of influence of human placenta-derived MSCs (P-MSCs) on the Lewis lung carcinoma (LLC) tumor development and metastatic potential is investigated in C57BL/6 mice depending on the injection method. After intramuscular co-inoculation of LLC and P-MSCs (LLC + P-MSCs), the growth of primary tumor and angiogenesis are slowed down compared to the control LLC on the 15th day. This is explained by the fact of a decrease in the secretion of proangiogenic factors during in vitro co-cultivation of an equal amount of LLC and P-MSCs. When P-MSCs are intravenously (i.v.) injected in the mice with developing LLC (LLC + P-MSCs(i.v.)), the tumor growth and angiogenesis are stimulated on the 15th day. A highly activated secretion of proangiogenic factors by P-MSCs in a similar in vitro model can explain this. In both the models compared to the control on the 23rd day, there is no significant difference in the tumor growth, while angiogenesis remains correspondingly decelerated or stimulated. However, in both the models, the total volume and number of lung metastases constantly increase compared to the control: it is mainly due to small-size metastases for LLC + P-MSCs(i.v.) and larger ones for LLC + P-MSCs. The increase in the rate of LLC cell dissemination after the injection of P-MSCs is explained by the disordered polyploidy and chromosomal instability, leading to an increase in migration and invasion of cancer cells. After LLC + P-MSCs co-inoculation, the tumor cell karyotype has the most complex and heterogeneous chromosomal structure. These findings indicate a bidirectional effect of P-MSCs on the growth of LLC in the early periods after injection, depending on the injection method, and, correspondingly, the number of contacting cells. However, regardless of the injection method, P-MSCs are shown to increase LLC aggressiveness related to cancer-associated angiogenesis and metastasis activation in the long term.

Near-infrared light reduces ß-amyloid-stimulated microglial toxicity and enhances survival of neurons: mechanisms of light therapy for Alzheimer's disease.

BACKGROUND: Low-intensity light can decelerate neurodegenerative disease progression and reduce amyloid ß (Aß) levels in the cortex, though the cellular and molecular mechanisms by which photobiomodulation (PBM) protects against neurodegeneration are still in the early stages. Microglia cells play a key role in the pathology of Alzheimer's disease by causing chronic inflammation. We present new results concerning the PBM of both oxidative stress and microglia metabolism associated with the activation of metabolic processes by 808 nm near-infrared light. METHODS: The studies were carried out using healthy male mice to obtain the microglial cell suspension from the hippocampus. Oligomeric ß-amyloid (1-42) was prepared and used to treat microglia cells. Light irradiation of cells was performed using diode lasers emitting at 808 nm (30 mW/cm2 for 5 min, resulting in a dose of 10 J/cm2). Mitochondrial membrane potential, ROS level studies, cell viability, apoptosis, and necrosis assays were performed using epifluorescence microscopy. Phagocytosis, nitric oxide and H2O2 production, arginase, and glucose 6-phosphate dehydrogenase activities were measured using standard assays. Cytokines, glucose, lactate, and ATP were measurements with ELISA. As our data were normally distributed, two-way ANOVA test was used. RESULTS: The light induces a metabolic shift from glycolysis to mitochondrial activity in pro-inflammatory microglia affected by oligomeric Aß. Thereby, the level of anti-inflammatory microglia increases. This process is accompanied by a decrease in pro-inflammatory cytokines and an activation of phagocytosis. Light exposure decreases the Aß-induced activity of glucose-6-phosphate dehydrogenase, an enzyme that regulates the rate of the pentose phosphate pathway, which activates nicotinamide adenine dinucleotide phosphate oxidases to further produce ROS. During co-cultivation of neurons with microglia, light prevents the death of neurons, which is caused by ROS produced by Aß-altered microglia. CONCLUSIONS: These original data clarify reasons for how PBM protects against neurodegeneration and support the use of light for therapeutic research in the treatment of Alzheimer's disease.

Red and near infrared light-stimulated angiogenesis mediated via Ca2+ influx, VEGF production and NO synthesis in endothelial cells in macrophage or malignant environments.

Irradiation with red or near-infrared (NIR) light in low level light therapy (LLLT) is found to stimulate cellular processes and bioenergetics, resulting in enhanced wound healing, pain control, neurodegenerative diseases treatment, etc. During light irradiation of tissues and organs, different cells are affected, though the connection between photostimulation of cells and their environmental conditions remains poorly understood. In this report, red/NIR light-stimulated angiogenesis is investigated using endothelial cells in vitro, with a focus on the capillary-like structure (CLS) formation and the respective biochemical processes in cells under conditions proximate to a healthy or malignant environment, which strongly defines angiogenesis. To model environmental conditions for endotheliocytes in vitro, the cell culture environment was supplemented by an augmented conditioned medium from macrophages or cancer cells. The biochemical processes in endothelial cell cultures were investigated with and without irradiation by red (650 nm) and near-infrared (808 nm) laser diodes and under normoxia or hypoxia conditions. A light-stimulated angiogenesis has been found, with a more efficient stimulation by 650 nm light compared to 808 nm light. It was shown that the irradiation with light promoted extracellular Ca2+ influx, fostered cell cycle progression, proliferation and NO generation in endothelial cells, and caused an increase in vascular endothelial growth factor (VEGF) production by endothelial cells and M2 macrophages under hypoxia conditions. The activation of VEGF production by macrophages was found to be associated with an increase in the number of M2 macrophages after light irradiation under hypoxia conditions. Thus, a new pathway of an activation of the endothelial cell metabolism, which is related with the extracellular Ca2+ influx after light irradiation, has been revealed. STATEMENT OF SIGNIFICANCE: Red/NIR light-stimulated angiogenesis has been studied using endothelial cells in vitro, with focus on CLS formation and the respective biochemical processes in cell models proximate to a healthy or malignant environment. A light-stimulated angiogenesis has been found, stimulated via extracellular Ca2+ influx, cell cycle progression, proliferation and NO generation, VEGF production increase by endothelial cells under hypoxia conditions.

NMDA receptor expression during cell transformation process at early stages of liver cancer in rodent models.

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, which is not sensitive to radiotherapy and chemotherapy and very often experiences postoperative relapse. In this regard, effective screening of liver cancer is considered as the most important and urgent task. The aim of our study was to determine whether N-methyl-D-aspartate receptor (NMDAR) and, in particular, its subunits, can serve as biomarkers to distinguish the precancerous liver at early stages of liver fibrosis. We assessed the development of HCC after 10, 15, and 22 wk using a HCC rat model. The expression of NMDAR subunits was monitored at different stages of HCC by means of immunohistochemistry combined with epifluorescence microscopy imaging, Western blotting, and direct bisulfite sequencing. NMDAR subunits were not found in healthy liver tissues. In contrast, NMDAR subunits, in particular NR1 and NR2B, appeared at the stage of severe liver fibrosis (precancerous liver disease) in rats and were expressed during the development of HCC in rats and mice. Using the direct bisulfite sequencing, we detected that increased expression of NMDAR directly correlated with the demethylation of CpG islands in the promoter region of genes encoding receptor subunits. The obtained results confirmed that NMDAR subunits can serve as new biomarkers of precancerous liver disease, severe fibrosis, and its progression towards HCC.NEW & NOTEWORTHY We have shown NMDAR expression in cell transformation process at early stages of cancer, specifically HCC. The aim of our study was to define the disease stages from precancerous liver disease towards liver cancer progression when NMDAR subunits were expressed/detected. A fibrosis/HCC rat model, immunohistochemistry combined with epifluorescence microscopy imaging, Western blotting was used. The dynamics of appearance of NMDAR subunits, their expression and methylation status during the development of HCC were shown and discussed.

Macrophages Modulated by Red/NIR Light: Phagocytosis, Cytokines, Mitochondrial Activity, Ca2+ Influx, Membrane Depolarization and Viability.

Low-level light therapy (LLLT) is emerging as a promising therapeutic approach to modulate the biochemical and molecular processes within living cells. LLLT is known to produce local and systemic effects; therefore, immune cells in local tissues or in the circulation are affected by light. However, this specific effect remains weakly explored. In this study, the effect of red (650 nm) and NIR (808 nm) light on phagocytosis (respiratory burst), cytokine expression, mitochondrial activity, ROS generation, Ca2+ influx and membrane depolarization in macrophages in vitro is investigated. Both the phagocytic capacity and adhesion of macrophages strongly (~2.5 times) increased in the first hours after exposure to light in a dose-dependent manner. The light-evoked upregulation of phagocytosis is found to be less efficient than the maximal pharmacologically induced enhancement of ~3.2 times. Also, red/NIR light reduces the production of pro-inflammatory cytokines and activates the secretion of anti-inflammatory cytokines by several times in activated macrophages. At the same time, the viability shows a biphasic dose response: it increases after irradiation with lower doses (0.3-1 J cm-2 ) and decreases after treatment with higher doses (18-30 J cm-2 ), which is apparently associated with the upregulation of ROS generation, followed by an increase in the mitochondrial activity.

Red and near-infrared light evokes Ca2+ influx, endoplasmic reticulum release and membrane depolarization in neurons and cancer cells.

Low level light therapy uses light of specific wavelengths in red and near-infrared spectral range to treat various pathological conditions. This light is able to modulate biochemical cascade reactions in cells that can have important health implications. In this study, the effect of low intensity light at 650, 808 and 1064 nm on neurons and two types of cancer cells (neuroblastoma and HeLa) is reported, with focus on the photoinduced change of intracellular level of Ca2+ ions and corresponding signaling pathways. The obtained results show that 650 and 808 nm light promotes intracellular Ca2+ elevation regardless of cell type, but with different dynamics due to the specificities of Ca2+ regulation in neurons and cancer cells. Two origins responsible for Ca2+ elevation are determined to be: influx of exogenous Ca2+ ions into cells and Ca2+ release from endoplasmic reticulum. Our investigation of the related cellular processes shows that light-induced membrane depolarization is distinctly involved in the mechanism of Ca2+ influx. Ca2+ release from endoplasmic reticulum activated by reactive oxygen species generation is considered as a possible light-dependent signaling pathway. In contrast to the irradiation with 650 and 808 nm light, no effects are observed under 1064 nm irradiation. We believe that the obtained insights are of high significance and can be useful for the development of drug-free phototherapy.