Background: Breast cancer is one of the most commonly diagnosed cancers in women, with high morbidity and mortality. Tumor metastasis is implicated in most breast cancer deaths; thus, inhibiting metastasis may provide a therapeutic direction for breast cancer. In the present study, pyropheophorbide-α methyl ester-mediated photodynamic therapy (MPPa-PDT) was used to inhibit metastasis in MCF-7 breast cancer cells. Methods: Uptake of MPPa was detected by fluorescence microscopy. Cell viability was evaluated by the Cell Counting Kit-8 (CCK-8). ROS generation was detected by 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA). The migration of cells was assessed by wound healing assay, and invasion ability was assessed by Matrigel invasion assay. Levels of MMP2 and MMP9 were measured by PCR. Akt, phospho-Akt (Ser473), phospho-NF-κB p65 (Ser536) and NF-κB p65 were measured by western blotting. The F-actin cytoskeleton was observed by immunofluorescence. Lung tissue was visualized by hematoxylin and eosin staining. Results: Following MPPa-PDT, migration and invasion were decreased in the MCF-7 cells. MPPa-PDT downregulated the expression of MMP2 and MMP9, which are responsible for the initiation of metastasis. MPPa-PDT reduced the phosphorylation of Akt and NF-κB. MPPa-PDT also reduced the expression of F-actin in cytoskeleton in MCF-7 cells. These effects were blocked by the reactive oxygen species scavenger NAC or the Akt activator SC79, while the PI3K inhibitor LY294002 or the Akt inhibitor triciribine enhanced these effects. Moreover, MPPa-PDT inhibited tumor metastasis and destroyed F-actin in vivo. Conclusion: Taken together, these results demonstrate that MPPa-PDT inhibits the metastasis of MCF-7 cells both in vitro and in vivo and may be involved in the Akt/NF-κB-dependent MMP-9 signaling pathway. Thus, MPPa-PDT may be a promising treatment to inhibit metastasis.

Photodynamic therapy (PDT) is a promising treatment in cancer therapy, with a photosensitizer activated by visible light. Aloe‐emodin (AE) is a promising photosensitive agent. In this study, the photosensitizing effects and possible mechanisms of AE‐PDT in MG63 cells were evaluated. The efficiency of AE‐PDT was analyzed by MTT assay. The mode of cell death was investigated by Hoechst 33,342 staining and flow cytometer. The intracellular distribution of AE was detected with confocal microscopy. The formation of reactive oxygen species (ROS) was detected by DCFH‐DA. The mitochondrial membrane potential (MMP) was measured by Rhodamine 123. The expression of proteins including cytochrome c, caspase‐3, ‐9, and ‐12, CHOP and GRP78 was detected by western blot. Apoptosis is the primary mode of cell death in our study, which occurs in a manner of depending on AE concentration and irradiation dose. Confocal microscopy showed that AE was primarily localized on the mitochondria and endoplasmic reticulum (ER) of MG63 cells. AE‐PDT resulted in rapid increases of intracellular ROS production, which reached a peak at 2 h, followed by declining of mitochondrial membrane potential, releasing of cytochrome c from mitochondria into the cytoplasm, and up‐regulation of caspase‐3, ‐9, and ‐12, CHOP and GRP78. These results suggest that death of MG63 cells induced by AE‐PDT is triggered by ROS. Meanwhile, Mitochondria and ER serve as the subcellular targets, which are responsible for AE‐PDT‐induced death of MG63 cells.

Photodynamic therapy (PDT), as a clinical cancer therapy, is a mild therapy, which involves application of photosensitizers (PSs) which located in target cells and then be irradiated by corresponding wawelength. The activation of PSs generates radical oxygenspecies ( ROS) to exert a selective cytotoxic activity for the target cells. Aloeemodin (AE) has been found to be a anti-tumor agent in many studies, and it also demonstrated to be a photosensitizer in recent years. In order to study the mechanism of aloe-emodin as a photosensitizer. In the present study, we investigated the mechanisms of photo-cytotoxicity induced by aloe-emodin in breast cancer MCF-7 cells. Analysis of cell proliferation evidenced that there was a dramatically depression after photodynamic treatment with aseries of aloe-emodin concentration and light doses showed. We observed changes apoptosis and demonstrated that the mechanisms of apoptosis were involved of mitochondrial and endoplasmic reticulum death pathway. The capacity of adhesion, migration and invasion of breast cells were measured usingWST8 and transwell assay and demonstrated that AE-PDT significantly inhibited adhesion, migration and invasion of MCF-7cells. The expression of MMP2, MMP9, VEGF and Nrf2 demonstrated that the metastasis was related to oxidative stress. Analysis of changes in cytoskeleton components (F-actin) evidenced cytoskeleton disorganization after treatment with AE-PDT. Taken together, the present results indicated that PDT with aloe emodin effectively suppressed cancer development in MCF-7cells, suggesting the potential of AE as one new photosensitizer in PDT can provide a new modility for treating cancer

Autophagy and ER stress participated in the inhibition of MPPa‐PDT on tumor growth, but the molecular links between them remain undefined. We just explore the molecular mechanism between them in vitro and vivo. CCK‐8 assay and flow cytometer were used to detect the cytotoxicity and mode of cell death after MPPa‐PDT. Furthermore, the role of autophagy was verified in MPPa‐PDT. Confocal microscopy was used to show the intracellular distribution of MPPa. ER stress markers and PERK signaling pathway were detected by western blot. While in vivo, tumor histology and immunohistochemistry were performed to show the effect of MPPa‐PDT in mice. After MPPa‐PDT, cells viability decreased in dose‐dependent manner. Besides, the cell apoptosis increased along with the increasing of Beclin‐1and LC3B II but declining of P62. When pretreated with 3‐MA, LC3B II formation and the cytotoxicity declined. MPPa‐PDT caused increasing of ER stress markers (GRP78, CHOP) as MPPa accumulated in ER. However, pretreatment with ER stress inhibitor 4PBA, the expression of GRP78 and LC3B II was blocked but the PERK signaling pathway activated and the expression of P62 increased. In vivo, the tumor growth was significantly inhibited by MPPa‐PDT. Besides, the appearance of ER stress and autophagy was further demonstrated by immunohistochemistry. Our findings demonstrate that autophagy mediated by MPPa‐PDT was regulated by ER stress, via PERK signaling pathway, to kill MDA‐MB‐231 cells in vitro and vivo.

Transcranial direct current stimulation (tDCS) has an impact on improving cognitive and motor dysfunction induced by ischemia-reperfusion injury. However, to use this technology more rationally in clinical practice, a deepened understanding of the molecular mechanisms behind its therapeutic effects is needed. This study explored the role of the brain-derived neurotrophic factor(BDNF) and its associated receptor tropomyosin-receptor kinase B(TrkB) while deciphering the underlying mechanisms in transcranial direct current therapy to treat ischemic stroke. A middle cerebral artery occlusion-reperfusion(MCAO/R) model was established in rats to observe tDCS effects on brain damage. Behavioral tests, the modified neurologic severity score(mNSS), and the Hoffman reflex / the M wave(H_max/M_max) ratio helped assess motor function and neurologic deficits. HE and Nissl staining helped observe the morphological changes and count of nerve cells. We tested the expression of growth-associated protein-43(Gap-43) and microtubule-associated protein-2(Map-2), K⁺-Cl^- co-transporter 2(KCC2), γ-aminobutyric acid(GABA), and key BDNF-TrkB downstream signaling, the phospholipase C gamma(PLCγ) / CaMK IV / cAMP response element binding protein(CREB), and extracellular signal-regulated protein kinase(ERK1/2) / ribosomal S6 kinase(RSK) using western blotting. Moreover, BDNF was analyzed in plasma using the enzyme-linked immunosorbent assay (ELISA) to investigate the tDCS effect on human BDNF expression levels. Finally, a BDNF receptor antagonist, ANA-12, was administered to explore the tDCS mechanism mediating BDNF-TrkB signaling. After tDCS treatment, the mNSS was improved, and the motor function was restored. Moreover, tDCS decreased cell swelling after MCAO/R and enhanced the number of neurons. tDCS treatment increased: (1) BDNF, Gap-43, Map-2 expression, (2) KCC2, GABA, and (3) PLCγ, CaMK IV, CREB and ERK1/2, RSK. Furthermore, ELISA results indicate that tDCS elevated human plasma BDNF protein expression. However, the therapeutic effect of tDCS was suppressed to a certain extent by adding ANA-12. Our findings indicate that tDCS may exert a neuroprotective effect by activating the downstream key molecules of BDNF-TrkB expression, for instance, PLCγ/ CaMK IV/ CREB and ERK/ RSK pathway. Moreover, tDCS can control neuronal excitability, promote axonal regeneration, and accelerate motor function recovery in ischemia reperfusion-injured rats.

Gastric carcinoma (GC) has high incidence and mortality rates in China. Surgery and chemotherapy are the main treatments. Photodynamic therapy (PDT) has become a new treatment modality, appearing in recent experimental studies and clinical trials in various tumors. This study explores the combined effect of gene transfection with PDT on GC cells using aloe emodin (AE)–encapsulated nanoliposomes, which acted as gene carrier as well as one photosensitizer (PS). AE‐encapsulated nanoliposomes (nano‐AE) were prepared by reverse evaporation method. Electron microscopy and nano‐ZS90 analyzer were used to detect its morphology, size, and wavelength. Western blot was used to detect the expression of the caspase‐3 after transfection. MTT assay and flow cytometry were employed to determine the cytotoxic and apoptotic rates, respectively. Hoechst 33342 staining was adopted to detect the morphological changes in death gastric cancer cells. Cellular reactive oxygen species (ROS) contents were measured by DCFH‐DA staining. Outcomes demonstrated that the nano‐AE has good properties as gene delivery carriers as well as a PS. The group in which the recombinant plasmid of r‐caspase‐3 was transfected had higher protein expression of the caspase‐3 than controls, meanwhile the proliferation rates of the transfected cells were inhibited by the nano‐AE‐mediated PDT in an energy‐dependent manner. In addition, in the transfected cells, the death rate increased to 77.3% as assessed 12 h after PDT (6.4 J/cm²). Hochest 33342 staining also revealed that the death rate increased significantly in the transfected group compared with other groups. Compared to control groups, the production of ROS in nano‐AE PDT group had quadrupled in SGC‐7901 cells as early as 1 h after PDT, while it is similar to the group of nano‐AE transfection and PDT. Nano‐AE‐mediated r‐caspase‐3 gene transfection coupled with PDT could inhibit the proliferation rate and increase the apoptotic rate remarkably in human gastric cancer cells.