Photosensitive Small Extracellular Vesicles Regulate the Immune Microenvironment of Triple Negative Breast Cancer

Currently, the treatment of triple-negative breast cancer (TNBC) is limited by the special pathological characteristics of this disease. In recent years, photodynamic therapy (PDT) has created new hope for the treatment of TNBC. Moreover, PDT can induce immunogenic cell death (ICD) and improve tumor immunogenicity. However, even though PDT can improve the immunogenicity of TNBC, the inhibitory immune microenvironment of TNBC still weakens the antitumor immune response. Therefore, we used the neutral sphingomyelinase inhibitor GW4869 to inhibit the secretion of small extracellular vesicles (sEVs) by TNBC cells to improve the tumor immune microenvironment and enhance antitumor immunity. In addition, bone mesenchymal stem cell (BMSC)-derived sEVs have good biological safety and a strong drug loading capacity, which can effectively improve the efficiency of drug delivery. In this study, we first obtained primary BMSCs and sEVs, and then the photosensitizers Ce6 and GW4869 were loaded into the sEVs by electroporation to produce immunomodulatory photosensitive nanovesicles (Ce6-GW4869/sEVs). When administered to TNBC cells or orthotopic TNBC models, these photosensitive sEVs could specifically target TNBC and improve the tumor immune microenvironment. Moreover, PDT combined with GW4869-based therapy showed a potent synergistic antitumor effect mediated by direct killing of TNBC and activation of antitumor immunity. Here, we designed photosensitive sEVs that could target TNBC and regulate the tumor immune microenvironment, providing a potential approach for improving the effectiveness of TNBC treatment. STATEMENT OF SIGNIFICANCE: We designed an immunomodulatory photosensitive nanovesicle (Ce6-GW4869/sEVs) with the photosensitizer Ce6 to achieve photodynamic therapy and the neutral sphingomyelinase inhibitor GW4869 to inhibit the secretion of small extracellular vesicles (sEVs) by triple-negative breast cancer (TNBC) cells to improve the tumor immune microenvironment and enhance antitumor immunity. In this study, the immunomodulatory photosensitive nanovesicle could target TNBC cells and regulate the tumor immune microenvironment, thus providing a potential approach for improving the treatment effect in TNBC. We found that the reduction in tumor sEVs secretion induced by GW4869 improved the tumor-suppressive immune microenvironment. Moreover, similar therapeutic strategies can also be applied in other kinds of tumors, especially immunosuppressive tumors, which is of great value for the clinical translation of tumor immunotherapy.

[The relationship between insulin resistance and risk of long-term mortality in people without diabetes: a 30-year follow-up of the Daqing Diabetes Study]

Objective: To determine whether insulin resistance is associated with all-cause mortality in subjects without diabetes. Methods: A total of 505 participants without diabetes, 198 with normal glucose tolerance (NGT) and 307 with impaired glucose tolerance (IGT), were recruited from the Daqing Diabetes Study. The participants were followed up for 30 years. They were stratified into three groups (tertiles) according to baseline homeostasis model assessment of insulin resistance(HOMA-IR) levels, as the HOMA-IR 0, the HOMA-IR 1 and the HOMA-IR 2 groups, to assess the predictive effect of insulin resistance on risk of all-cause mortality. Results: During the 30-year follow-up, 52, 56 and 78 participants died across the three HOMA-IR groups, respectively. The corresponding mortality per 1 000 person-years (95%CI) were 12.12 (9.56-15.01), 13.10 (10.46-16.03) and 19.91 (16.73-23.15), respectively. Participants in the HOMA-IR 2 group had a significantly higher risk of death than those in the HOMA-IR 0 group after adjustment of age, sex and smoking status (HR=1.97,95%CI 1.38-2.81, P<0.001). Cox analyses showed that a one standard deviation increase in HOMA-IR was associated with a 22% increase in the mortality after adjustment of potential confounders (HR=1.22, 95%CI 1.08-1.39, P=0.002). Conclusions: Insulin resistance is associated with increased risk of all-cause death in Chinese people without diabetes, suggesting that improving insulin resistance could be beneficial for people without diabetic in reducing risk of long-term all-cause mortality.

[Subjects with impaired glucose tolerance returned to normal glucose status for six years had lower long-term risk of diabetes: 20 years follow up of Daqing diabetes prevention study]

Objective: To explore the influence of lifestyle intervention on long-term diabetes in subjects with impaired glucose tolerance (IGT) returned to normal glucose tolerance (NGT) within 6 years. Methods: A total of 577 subjects (aged 25-74 years old) with IGT in Daqing were enrolled and randomly assigned to control, and diet, exercise and diet plus exercise groups in a six-year intervention trial in 1986. Subjects who were non-diabetic at the end of the intervention were followed up for additional 14 years. Results: Among all the subjects, 41.38% of them who had returned to NGT from IGT within 6 years maintained NGT status after 20 years, and had a lower incidence of diabetes than subjects maintained IGT status (46.55% vs. 75.25%). Of note, in the intervention group, the percentage of participants developed diabetes in the NGT subjects was significantly lower than that in the IGT group (43.71% vs. 76.25%) after 20 years. There was high long-term risk for diabetes in the IGT subjects after the adjustment of age, sex and baseline glucose (HR=1.81, 95%CI 1.27-2.58, P=0.001), whereas in the non-intervention group, no significant difference could be viewed in long-term diabetic risk between subjects maintained IGT status and those returned to NGT (71.43% vs. 65.22%) after adjusting of the same confounders (HR=1.03, 95%CI 0.45-2.35, P=0.94). Conclusions: IGT subjects who had returned to NGT in early years had lower risk for future diabetes than those who remained IGT. However, this beneficial effect could only be viewed in the intervention group, but not in the non-intervention group.

Endothelial Progenitor Cells Combined with Cytosine Deaminase-Endostatin for Suppression of Liver Carcinoma

Transplantation of gene transfected endothelial progenitor cells (EPCs) provides a novel method for treatment of human tumors. To study treatment of hepatocellular carcinoma using cytosine deaminase (CD)- and endostatin (ES)-transfected endothelial progenitor cells (EPCs), mouse bone marrow-derived EPCs were cultured and transfected with Lenti6.3-CD-EGFP and Lenti6.3-ES-Monomer-DsRed labeled with superparamagnetic iron oxide (SPIO) nanoparticles. DiD (lipophilic fluorescent dye)-labeled EPCs were injected into normal mice and mice with liver carcinoma. The EPCs loaded with CD-ES were infused into the mice through caudal veins and tumor volumes were measured. The tumor volumes in the EPC + SPIO + CD/5-Fc + ES group were found to be smaller as a result and grew more slowly than those from the EPC + SPIO + LV (lentivirus, empty vector control) group. Survival times were also measured after infusion of the cells into the mice. The median survival time was found to be longer in the EPC + SPIO + CD/5-Fc + ES group than in the others. In conclusion, the EPCs transfected with CD-ES suppressed the liver carcinoma cells in vitro, migrated primarily to the carcinoma, inhibited tumor growth, and also extended the median survival time for the mice with liver carcinoma.

Magnetic resonance imaging of post-ischemic blood-brain barrier damage with PEGylated iron oxide nanoparticles

Blood-brain barrier (BBB) damage during ischemia may induce devastating consequences like cerebral edema and hemorrhagic transformation. This study presents a novel strategy for dynamically imaging of BBB damage with PEGylated supermagnetic iron oxide nanoparticles (SPIONs) as contrast agents. The employment of SPIONs as contrast agents made it possible to dynamically image the BBB permeability alterations and ischemic lesions simultaneously with T2-weighted MRI, and the monitoring could last up to 24 h with a single administration of PEGylated SPIONs in vivo. The ability of the PEGylated SPIONs to highlight BBB damage by MRI was demonstrated by the colocalization of PEGylated SPIONs with Gd-DTPA after intravenous injection of SPION-PEG/Gd-DTPA into a mouse. The immunohistochemical staining also confirmed the leakage of SPION-PEG from cerebral vessels into parenchyma. This study provides a novel and convenient route for imaging BBB alteration in the experimental ischemic stroke model.

Preparation of folic acid-conjugated, doxorubicin-loaded, magnetic bovine serum albumin nanospheres and their antitumor effects in vitro and in vivo

BACKGROUND

This study aimed to generate targeted folic acid-conjugated, doxorubicin-loaded, magnetic iron oxide bovine serum albumin nanospheres (FA-DOX-BSA MNPs) that lower the side effects and improve the therapeutic effect of antitumor drugs when combined with hyperthermia and targeting therapy. A new nanodrug using magnetic nanospheres for heating and addition of the folate receptor with cancer cell specificity was prepared. The characteristics of these nanospheres and their antitumor effects in nasopharyngeal carcinoma were explored.

METHODS

FA-DOX-BSA MNPs comprising encapsulated magnetic iron oxide nanoparticles were prepared using a desolvation cross-linking method. Activated folic acid (N-hydroxysuccinimide ester of folic acid) was conjugated to the surface of albumin nanospheres via amino groups.

RESULTS

Folic acid was successfully expressed on the surface of the nanospheres. Electron microscopy revealed that the FA-DOX-BSA MNPs were nearly spherical and uniform in size, with an average diameter of 180 nm. The nanomaterial could deliver doxorubicin at clinically relevant doses with an entrapment efficiency of 80%. An increasing temperature test revealed that incorporation of magnetic iron oxide into nanospheres could achieve a satisfactory heat treatment temperature at a significantly lower dose when placed in a high-frequency alternating magnetic field. FA-DOX-BSA MNPs showed greater inhibition of tumors than in the absence of folic acid in vitro and in vivo. Compared with chemotherapy alone, hyperthermia combined with chemotherapy was more effective against tumor cells.

CONCLUSION

Folic acid-conjugated bovine serum albumin nanospheres composed of mixed doxorubicin and magnetic iron oxide cores can enable controlled and targeted delivery of anticancer drugs and may offer a promising alternative to targeted doxorubicin therapy for nasopharyngeal carcinoma.

Genetic immunotherapy for hepatocellular carcinoma by endothelial progenitor cells armed with cytosine deaminase

Endothelial progenitor cells (EPCs) serve as cellular vehicles for targeting cancer cells and are a powerful tool for delivery of therapeutic genes. Cytosine deaminase (CD), a kind of frequent suicide gene which can kill carcinoma cells by converting a non-poisonous pro-drug 5-flucytosine (5-FC) into a poisonous cytotoxic 5-fluorouracil (5-FU). We combined super-paramagnetic iron oxide (SPIO) nanoparticles labeled EPCs with CD gene to treat grafted liver carcinomas and tracked them with 7.0 T Magnetic resonance imaging (MRI). Results showed that the therapeutic EPCs loaded with CD plus 5-Fc provided stronger carcinoma growth suppression compared with treatment using CD alone. The CD/5-Fc significantly inhibited the growth of endothelial cells and induced carcinoma cells apoptosis. These results indicate that EPCs transfected with anti-carcinoma genes can be used in carcinoma therapy as a novel therapeutic modality.

Involvement of epidermal growth factor receptor overexpression in the promotion of breast cancer brain metastasis

BACKGROUND

Brain-metastatic breast cancer (BMBC) is increasing and poses a severe clinical problem because of the lack of effective treatments and because the underlying molecular mechanisms are largely unknown. Recent work has demonstrated that deregulation of epidermal growth factor receptor (EGFR) may correlate with BMBC progression. However, the exact contribution that EGFR makes to BMBC remains unclear.

METHODS

The role of EGFR in BMBC was explored by serial analyses in a brain-trophic clone of human MDA-MB-231 breast carcinoma cells (231-BR cells). EGFR expression was inhibited by stable short-hairpin RNA transfection or by the kinase inhibitor erlotinib, and it was activated by heparin-binding epidermal growth factor-like growth factor (HB-EGF). Cell growth and invasion activities also were analyzed in vitro and in vivo.

RESULTS

EGFR inhibition or activation strongly affected 231-BR cell migration/invasion activities as assessed by an adhesion assay, a wound-healing assay, a Boyden chamber invasion assay, and cytoskeleton staining. Also, EGFR inhibition significantly decreased brain metastases of 231-BR cells in vivo. Surprisingly, changes to EGFR expression affected cell proliferation activities less significantly as determined by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, an anchorage-independent growth assay, and cell cycle analysis. Immunoblot analysis suggested that EGFR drives cells' invasiveness capability mainly through phosphoinositide 3-kinase/protein kinase B and phospholipase C γ downstream pathways. In addition, EGFR was involved less in proliferation because of the insensitivity of the downstream mitogen-activated protein kinase pathway.

CONCLUSIONS

The current results indicated that EGFR plays more important roles in cell migration and invasion to the brain than in cell proliferation progression on 231-BR cells, providing new evidence of the potential value of EGFR inhibition in treating BMBC.

[Manganese enhanced magnetic resonance imaging for tracing corticospinal tracts in rat brain using 7.0 T MRI]

OBJECTIVE

To investigate the methods of manganese enhanced magnetic resonance imaging in 7.0 T magnetic field for tracing corticospinal tract in rat brain in vivo.

METHODS

0.4 microl volume of 1 mol/L aqueous solution of MnCl(2) was injected into the primary motor cortex of 9 SD rats under stereotaxis. MRI studies were performed for tracing corticospinal tract and other coherent nerve tracts before injection and 24 hours, 48 hours, 72 hours, 7 days after injection respectively using 7.0T Micro-MRI.

RESULTS

Corticospinal tract was visualized perfectly from primary motor cortex, thalamus, cerebral peduncle to pons at different time points after Mn(2+) administration, and the best contrast was achieved after 24-48 h. At the same time, a small quantity of Mn(2+) reached the opposite somatosensory cortex through the corpus callosum.

CONCLUSION

Manganese enhanced MRI visualizes perfectly the transport of Mn(2+) through axoplasmic flow in corticospinal tracts. This method may be used to investigate the change of corticospinal tract and the functional connectivity between two sides of hemisphere in rat brain.

Enhancement of p53 gene transfer efficiency in hepatic tumor mediated by transferrin receptor through trans-arterial delivery

Transferrin-DNA complex mediated by transferrin receptor in combination with interventional trans-arterial injection into a target organ may be a duel-target-oriented delivery means to achieve an efficient gene therapy. In this study, transferrin receptor expression in normal human hepatocyte and two hepatocellular-carcinoma cells (Huh7/SK-Hep1) was determined. p53-LipofectAMINE with different amounts of transferrin was transfected into the cells and the gene transfection efficiency was evaluated. After VX2 rabbit hepatocarcinoma model was established, the transferrin-p53-LipofectAMINE complex was delivered into the hepatic artery via interventional techniques to analyze the therapeutic p53 gene transfer efficiency in vivo by Western blot, immunohistochemical/immunofluorescence staining analysis and survival time. The results were transferrin receptor expression in Huh7 and SK-Hep1 cells was higher than in normal hepatocyte. Transfection efficiency of p53 was increased in vitro in both Huh7 and SK-Hep1 cells with increasing transferrin in a dose-dependent manner. As compared to intravenous administration, interventional injection of p53-gene complex into hepatic tumor mediated by transferrin-receptor, could enhance the gene transfer efficiency in vivo as evaluated by Western blot, immunohistochemical/immunofluorenscence staining analyses and improved animal survival (H = 12.567, p = 0.0019). These findings show the transferrin-transferrin receptor system combined with interventional techniques enhanced p53-gene transfer to hepatic tumor and the duel-target-oriented gene delivery may be an effective approach for gene therapy.

[The electrostatic protection of the medical devices & equipments]

This paper describes the harms of the static electricity to medical devices & equipments and its protection.