Sheng Song

Antitumor immunologically modified carbon nanotubes for photothermal therapy

An immunologically modified nanotube system was developed using an immunoadjuvant, glycated chitosan (GC), as surfactant of single-walled carbon nanotube (SWNTs). This SWNT-GC system not only retained both optical properties of SWNTs and immunological functions of GC, but also could enter cells due to the carrier properties of SWNTs. Cellular SWNTs induced thermal destruction of tumor cells when irradiated by a near-infrared laser and, at the same time, cellular GC could serve both as damage associated molecular pattern molecules (DAMPs) and pathogen associated molecular pattern molecules (PAMPs) to enhance the tumor immunogenicity and enhance the uptake and presentation of tumor antigens, leading to special antitumor response. Using this system and a 980 nm laser, we treated tumors, both in vitro and in vivo, and investigated the induced thermal and immunological effects. Laser + SWNT-GC afford a remarkable efficacy in suppressing tumor growth in animal cancer models, in many cases resulting in complete tumor regression and long-term survival. Mice successfully treated by Laser + SWNT-GC could establish resistance to tumor rechallenge. This system forms a multifunctional temporal-spatial continuum, which can synergize photothermal and immunological effects. The Laser + SWNT-GC could represent a promising treatment modality to induce systemic antitumor response through a local intervention, while minimizing the adverse side effects.

Low-level laser therapy regulates microglial function through Src-mediated signaling pathways: implications for neurodegenerative diseases.

BackgroundActivated microglial cells are an important pathological component in brains of patients with neurodegenerative diseases. The purpose of this study was to investigate the effect of He-Ne (632.8 nm, 64.6 mW/cm2) low-level laser therapy (LLLT), a non-damaging physical therapy, on activated microglia, and the subsequent signaling events of LLLT-induced neuroprotective effects and phagocytic responses.MethodsTo model microglial activation, we treated the microglial BV2 cells with lipopolysaccharide (LPS). For the LLLT-induced neuroprotective study, neuronal cells with activated microglial cells in a Transwell™ cell-culture system were used. For the phagocytosis study, fluorescence-labeled microspheres were added into the treated microglial cells to confirm the role of LLLT.ResultsOur results showed that LLLT (20 J/cm2) could attenuate toll-like receptor (TLR)-mediated proinflammatory responses in microglia, characterized by down-regulation of proinflammatory cytokine expression and nitric oxide (NO) production. LLLT-triggered TLR signaling inhibition was achieved by activating tyrosine kinases Src and Syk, which led to MyD88 tyrosine phosphorylation, thus impairing MyD88-dependent proinflammatory signaling cascade. In addition, we found that Src activation could enhance Rac1 activity and F-actin accumulation that typify microglial phagocytic activity. We also found that Src/PI3K/Akt inhibitors prevented LLLT-stimulated Akt (Ser473 and Thr308) phosphorylation and blocked Rac1 activity and actin-based microglial phagocytosis, indicating the activation of Src/PI3K/Akt/Rac1 signaling pathway.ConclusionsThe present study underlines the importance of Src in suppressing inflammation and enhancing microglial phagocytic function in activated microglia during LLLT stimulation. We have identified a new and important neuroprotective signaling pathway that consists of regulation of microglial phagocytosis and inflammation under LLLT treatment. Our research may provide a feasible therapeutic approach to control the progression of neurodegenerative diseases.

Glycated chitosan as a new non-toxic immunological stimulant

Chitosan is capable of stimulating immune responses. However, because chitosan is not water soluble, it has limited biological applications. By attaching galactose molecules to the chitosan molecules, a new water-soluble compound, glycated chitosan (GC), was synthesized. GC was designed for immune stimulations in combination with phototherapies in the treatment of metastatic tumors. To investigate the possible toxicity of GC, cultures of normal and tumor cells were incubated with GC of different concentrations and the cell viabilities were determined. For in vivo studies, GC solution was fed or injected to animals and its toxicity was determined through observations of animals and histological examinations of vital organs. No toxic effects of GC were observed in cultured cells or in animal studies. In addition, the immunological effect of GC was investigated through its stimulation of TNFα secretion by macrophages in vitro. In vivo studies showed enhancement of the survival of laser immunotherapy-treated rats bearing metastatic mammary tumors. Our in vitro and in vivo results indicated that GC was a strong immunological stimulant. Its non-toxic nature and immunological activity make GC a potential immunoadjuvant for treatment of metastatic tumors.

PDT-induced HSP70 externalization up-regulates NO production via TLR2 signal pathway in macrophages

TLR2 and p85α physically interact by fluorescent resonance energy transfer (View interaction).

Immunostimulatory properties of glycated chitosan

Glycated chitosan (GC) is a new compound derived from chitosan by attaching galactose molecules to the chitosan molecules. GC was designed for immune stimulations in combination with phototherapies in the cancer treatment. The future clinical applications require a thorough understanding of the properties of GC. Murine macrophage cells (RAW264.7) were used to investigate NO formation and TNFα secretion stimulated by GC. Murine mammary tumor cells (EMT6) were treated in vitro and in vivo by laser irradiation with 980 nm in combination with GC stimulation. Here is the first in a series of studies designed to understand the immunological mechanisms of GC. Our in vitro results show that GC could enter into macrophages to stimulate NO generation and TNFα secretion. GC could further enhance the TNFα secretion of macrophages stimulated by laser treated tumor cells. Our in vivo results also show immunological effects of GC, particularly in inducing tumor-specific immune responses. Our results indicated that GC was a strong immunological stimulant for cancer treatment, particularly when combined with laser phototherapies.

ANTI-TUMOR RESPONSES INDUCED BY LASER IRRADIATION AND IMMUNOLOGICAL STIMULATION USING A MOUSE MAMMARY TUMOR MODEL

Anti-tumor immunological response induced by local intervention is ideal for treatment of metastatic tumors. Laser immunotherapy was developed to synergize photothermal interaction with immunological stimulation for cancer treatment. Using an infrared laser, indocyanine green (ICG, as a light absorbing agent), and glycated chitosan (GC, as an immunostimulant), laser immunotherapy has resulted in tumor suppression and anti-tumor responses in pre-clinical as well as clinical studies. To further understand the mechanism of laser immunotherapy, the effects of laser and GC treatment without specific enhancement of laser absorption were studied. Passive adoptive immunity transfer was performed using splenocytes as immune cells. Spleen cells harvested from tumor-bearing mice treated by laser + GC provided 60% immunity in naive recipients. Furthermore, cytotoxicity and TNF-α secretion by splenocytes from treated mice also indicated that laser + G induced immunity was tumor-specific. The high level of infiltrating T cells in tumors after laser + GC treatment further confirmed a specific anti-tumor immune response. Therefore, laser + GC could prove to be a promising selective local treatment modality that induces a systemic anti-tumor response, with appropriate laser parameters and GC doses.

HSP70 inhibits Bax translocation during Photofrin-PDT apoptosis

Apoptosis is an important cellular event that plays a key role in therapy of many diseases. The mechanisms of the initiation and regulation of photodynamic therapy (PDT) -induced apoptosis is complex. Some PDT-associated apoptosis pathways involved plasma membrane death receptors, mitochondria, lysosomes and endoplasmic reticulum (ER). Our previous study found that Photofrin were localized primarily in mitochondria, the primary targets of Photofrin-PDT. The key role of Bax in the mitochondrion-mediated apoptosis has been demonstrated in many systems. In order to determine the role of Bax in the mitochondrion-mediated apoptosis induced by Photofrin-PDT, we used the CFP/GFP-Bax plasmid to monitor the dynamics of Bax activation and translocation after PDT treatment. With laser scanning confocal microscopy, we found that PDT induced Bax translocation from the cytosol to mitochondria; however, with cells over-expressing YFP-HSP70 plasmids, Bax translocation was not detected. Thus, for Photofrin-PDT, Bax activation and translocation were inhibited by HSP70, not influence the cell death.

Low-power laser irradiation (LPLI) attenuates microglial cytotoxicity through the activation of Src pathway

It has been known for a long time that microglial activation plays an important role in the pathology of neurodegenerative diseases. Once activated, they have macrophage-like capabilities, which can be detrimental by producing proinflammatory and neurotoxic factors including cytokines, reactive oxygen species (ROS) and nitric oxide that directly or indirectly cause neurodegeneration. Therefore, the regulation of microglial-induced neuroinflammation is considered a useful strategy in searching for neuroprotective treatments. In this study, our results showed that low power laser irradiation (LPLI) (20 J/cm2) could suppress microglial-induced neuroinflammation in LPS-activated microglia. We found that LPLI-mediated neuroprotection was achieved by activating tyrosine kinases Src, which led to MyD88 tyrosine phosphorylation, thus impairing MyD88-dependent proinflammatory signaling cascade. Our research may provide a feasible therapeutic approach to control the progression of neurodegenerative diseases.

Special antitumor immune effects of laser immunotherapy with SWNT-GC

In our previous work, we constructed a multifunction nano system SWNT-GC, which can synergize photothermal and immunological effects. To further improve the application of this system, we study the cytotoxicity of SWNT-GC and investigate the effects on malignant tumor therapy. Here, we selected the optimal concentration of GC and SWNTs for the stable SWNT-GC construction. No cytotoxicity was observed under the dose used in the experiments. Using mouse melanoma tumor model, Laser+SWNT-GC treatment resulted in a significant mice survival rate, there were no long-term survivors under other treatment. It is providing a promising treatment modality for the malignancy.

Effects of LPLI on microglial phagocytosis in LPS-induced neuroinflammation model

Microglial activation plays an important role in neurodegenerative diseases. Once activated, they have macrophage-like capabilities, which can be beneficial by phagocytosis and harmful by secretion of neurotoxins. However, the resident microglia always fail to trigger an effective phagocytic response to clear dead cells or Aβ deposits during the progression of neurodegeneration. Therefore, the regulation of microglial phagocytosis is considered a useful strategy in searching for neuroprotective treatments. In this study, our results showed that low-power laser irradiation (LPLI) (20 J/cm2) could enhance microglial phagocytic function in LPS-activated microglia. We found that LPLI-mediated microglial phagocytosis is a Rac-1-dependent actin-based process, that a constitutively activated form of Rac1 (Rac1Q61L) induced a higher level of actin polymerization than cells transfected with wild-type Rac1, whereas a dominant negative form of Rac1 (Rac1T17N) markedly suppressed actin polymerization. In addition, the involvement of Rac1 activation after LPLI treatment was also observed by using a Raichu fluorescence resonance energy transfer (FRET)-based biosensor. We also found that PI3K/Akt pathway was required in the LPLI-induced Rac1 activation. Our research may provide a feasible therapeutic approach to control the progression of neurodegenerative diseases.