A Tumor-Penetrating Nanomedicine Improves the Chemoimmunotherapy of Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors with a low survival rate. The therapeutic effect of chemotherapy and immunotherapy for PDAC is disappointing due to the presence of dense tumor stroma and immunosuppressive cells in the tumor microenvironment (TME). Herein, a tumor-penetrating nanoparticle is reported to modulate the deep microenvironment of PDAC for improved chemoimmunotherapy. The tumor pH-sensitive polymer is synthesized by conjugating N,N-dipentylethyl moieties and monomethoxylpoly(ethylene glycol) onto PAMAM dendrimer, into whose cavity a hydrophobic gemcitabine (Gem) prodrug is accommodated. They self-assemble into nanoparticles (denoted as SPN@Pro-Gem) with the size around 120 nm at neutral pH, but switch into small particles (≈8 nm) at tumor site to facilitate deep delivery of Gem into the tumor parenchyma. In addition to killing cancer cells that resided deeply in the tumor tissue, SPN@Pro-Gem could modulate the TME by reducing the abundance of tumor-associated macrophages and myeloid-derived suppressor cells as well as upregulating the expression level of PD-L1 of tumor cells. This collectively facilitates the infiltration of cytotoxic T cells into the tumors and renders checkpoint inhibitors more effective in previously unresponsive PDAC models. This study reveals a promising strategy for improving the chemoimmunotherapy of pancreatic cancer.

Nanoparticle-Enabled Dual Modulation of Phagocytic Signals to Improve Macrophage-Mediated Cancer Immunotherapy.

Activation of the phagocytosis of macrophages to tumor cells is an attractive strategy for cancer immunotherapy, but the effectiveness is limited by the fact that many tumor cells express an increased level of anti-phagocytic signals (e.g., CD47 molecules) on their surface. To promote phagocytosis of macrophages, a pro-phagocytic nanoparticle (SNPACALR&aCD47 ) that concurrently carries CD47 antibody (aCD47) and a pro-phagocytic molecule calreticulin (CALR) is constructed to simultaneously modulate the phagocytic signals of macrophages. SNPACALR&aCD47 can achieve targeted delivery to tumor cells by specifically binding to the cell-surface CD47 and block the CD47-SIRPα pathway to inhibit the "don't eat me" signal. Tumor cell-targeted delivery increases the exposure of recombinant CALR on the cell surface and stimulates an "eat me" signal. Simultaneous modulation of the two signals enhances the phagocytosis of 4T1 tumor cells by macrophages, which leads to significantly improved anti-tumor efficacy in vivo. The findings demonstrate that the concurrent blockade of anti-phagocytic signals and activation of pro-phagocytic signals can be effective in macrophage-mediated cancer immunotherapy.

Angiopep-2 conjugated nanoparticles loaded with doxorubicin for the treatment of primary central nervous system lymphoma.

Primary central nervous system lymphoma (PCNSL) is a rare brain tumor. Its therapeutic efficacy is much lower than that of traditional lymphoma, largely due to the presence of the blood-brain barrier (BBB), which hinders the effective drug delivery and deposition on the disease site. Angiopep-2 (ANG) can target low-density lipoprotein receptor-related protein (LRP) on the surface of brain capillary endothelial cells (BCECs) and exhibits high BBB transport capability. In this study, we designed an ANG conjugated poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL) (APP) nanoparticle to deliver doxorubicin (DOX) for the treatment of PCNSL. Our data indicated that the targeted APP nanoparticles showed significantly increased cellular uptake by BCECs compared with the control nanoparticles. In the intracranial SU-DHL-2-LUC lymphoma xenograft mice model, APP enhanced drug deposition in tumor tissues, and DOX-loaded APP (APP@DOX) exhibited a better therapeutic effect than free DOX and nontargeted PP@DOX, which significantly prolonged the survival time of mice.

Astaxanthin attenuates total body irradiation-induced hematopoietic system injury in mice via inhibition of oxidative stress and apoptosis.

BACKGROUND: The hematopoietic system is especially sensitive to total body irradiation (TBI), and myelosuppression is one of the major effects of TBI. Astaxanthin (ATX) is a powerful natural anti-oxidant with low toxicity. In this study, the effect of ATX on hematopoietic system injury after TBI was investigated. METHODS: Flow cytometry was used to detect the proportion of hematopoietic progenitor cells (HPCs) and hematopoietic stem cells (HSCs), the level of intracellular reactive oxygen species (ROS), expression of cytochrome C, cell apoptosis, and NRF2-related proteins. Immunofluorescence staining was used to detect Nrf2 translocation. Western blot analysis was used to evaluate the expression of apoptotic-related proteins. Enzymatic activities assay kits were used to analyze SOD2, CAT, and GPX1 activities. RESULTS: Compared with the TBI group, ATX can improve radiation-induced skewed differentiation of peripheral blood cells and accelerate hematopoietic self-renewal and regeneration. The radio-protective effect of ATX is probably attributable to the scavenging of ROS and the reduction of cell apoptosis. These changes were associated with increased activation of Nrf2 and downstream anti-oxidative proteins, and regulation of apoptotic-related proteins. CONCLUSIONS: This study suggests that ATX could be used as a potent therapeutic agent to protect the hematopoietic system against TBI-induced bone marrow suppression.

[Differential expression of oxidative reductases in different subsets of mouse hematopoietic cells].

Hematopoietic stem cells (HSC) are the source of all blood cells, which can differentiate into various hematopoietic hierarchy cells. Physiological level of reactive oxygen species (ROS) plays an important role in regulating functions of HSC as excessive ROS is harmful to HSC. Oxidative reductases and antioxidants can eliminate cellular ROS to maintain ROS homeostasis and thus avoid excessive ROS-caused damages. There are several types of oxidative reductases in cells such as catalase, manganese superoxide dismutase (MnSOD), glutathione peroxidase 1 (GPX1), thioredoxin reductase 1 (Txrnd1) and Nqo1 [NAD(P)H dehydrogenase quinone 1]. However, the functional roles of various oxidative reductases in regulating ROS level in hematopoietic cells remain unclear. This study was to investigate the expression patterns of these oxidative reductases in mouse hematopoietic cells that were sorted out via flow cytometry and to find out important oxidative reductases involving in HSC ROS regulation. The expression of various oxidative reductases was detected by semi-quantitative real-time PCR. The results showed that the expression level of catalase in T cell population was 0.14 times that in LT-HSC population (P < 0.05). The expression levels of MnSOD in CLP population and myeloid cells were 0.56 and 0.47 times that in LT-HSC population respectively (P < 0.05). The expression levels of GPX1 in ST-HSC, GMP, Myeloid cells, MEP, T lymphocytes and B lymphocytes were 1.79, 2.96, 2.07, 0.58, 0.10, 0.6 times that in LT-HSC population respectively (P < 0.05). The expression levels of Txrnd1 in ST-HSC, MPP, CMP, GMP, Myeloid cells, T lymphocytes and B lymphocytes were 3.36, 3.18, 4.19, 6.39, 4.27, 0.016, 0.56 time that in LT-HSC population, respectively (P < 0.05). The expression levels of Nqo1 in ST-HSC, MPP, CMP, GMP, CLP and B cell were 0.30, 0.17, 0.25, 0.10, 0.04, 0.01 times that in LT-HSC population, respectively (P < 0.05). It is concluded that the expression levels of oxidative reductases (catalase, MnSOD, GPX1, Txrnd1 and Nqo1) in hematopoietic hierarchy cells are cell-type specific. It suggests that reductases may play divergent roles in various hematopoietic cell populations. More importantly, the expression level of Nqo1 in LT-HSC population significantly increased as compared with other cell populations, thereby suggesting its unique regulatory role in HSC.

Construction and Physical Mapping of the 35 cM YAC Contigs for the Region of Xp11.2 - p21.3.

One hundred and fifty-one YACs were selected from three libraries with a series of STS and other DNA probes of the human X chromosome p11.2 - p21.3 region. The YAC contigs, spanning about 35cM in all and generally cover the whole region, were constructed based on the physical analysis of the positive clones. A total of seventy-seven DNA markers of this region were located and ordered on this map with an average 454 kb spacing, in which fifty-three were polymorphic markers with an average 0.6 cM genetic spacing. These results facilitate the search for novel genes and the sequence analysis of this region.