Suppression of tumor growth and metastasis in Shkbp1 knockout mice.

Epidermal growth factor receptor (EGFR) is widely accepted in cancer diagnosis and targeted therapy. Shkbp1 is an upstream molecule of EGFR, which prevents EGFR degradation. However, the role of Shkbp1 in tumor remains to be clarified. Herein we induced tumor in the lungs of Shkbp1 knockout mice with chemical drugs to investigate the function of Shkbp1. Compared with wild-type mice, tumors in the lungs were significantly fewer in Shkbp1 knockout mice. To further explore the biological characteristics and functions of Shkbp1 in cancer cells, we established cell lines with overexpression and low expression of Shkbp1, respectively. Results from our experiments showed that low expression of Shkbp1 in lung cancer remarkably inhibited cancer cell migration and invasion, while overexpression of Shkbp1 promoted their migration and invasion, which indicated that Shkbp1 was closely related with tumor migration and invasion. The mRNA expression analysis of 494 matched tumor and adjacent non-tumor tissues (data derived from TCGA database) revealed that Shkbp1 was associated with the clinic TNM staging. Furthermore, immunohistochemistry (IHC) analysis of tissue microarrays showed that Shkbp1 was also correlated with lymphatic metastasis. Mechanistically, we observed that Shkbp1 was associated with epithelial-mesenchymal transition (EMT) marker. More interestingly, Shkbp1 was also expressed in a variety of immune cells, and we hereby used a subcutaneous transplantation tumor model and a metastasis model created by tail vein injection to explore whether Shkbp1 could impact tumor growth. The results showed that Shkbp1 knockout reduced tumor growth in both tumor models. In general, our results suggest that knocking out Shkbp1 in either immune cells or tumor cells could suppress tumor growth and metastasis.

Insight into the Assembling Mechanism of Cryptococcus Capsular Glucuronoxylomannan Based on Molecular Dynamics Simulations.

Cryptococcus spp. is an invasive fungal pathogen and causes life-threatening cryptococcosis. Opportunistic cryptococcal infections among the immunocompromised population are mostly caused by Cryptococcus neoformans, whereas the geographical dissemination of Cryptococcus gattii in recent years has threatened lives of even immunocompetent people. The capsule, mainly composed of glucuronoxylomannan (GXM) polysaccharides, plays important roles in the virulence of Cryptococcus spp. The assembling mechanism of GXM polysaccharides into the capsule is little understood because of insufficient experimental data. Molecular modeling and molecular dynamics simulation provide insight into the assembling process. We first built GXM oligosaccharide models of serotypes D, A, B, and C and extracted their secondary structure information from simulation trajectories. All the four mainchains tend to take the nearly twofold helical conformation, whereas peripheral sidechains prefer to form left-handed helices, which are further stabilized by intramolecular hydrogen bonds. Based on the obtained secondary structure information, GXM polysaccharide arrays were built to simulate capsule-assembling processes of C. neoformans and C. gattii using serotypes A and C as representatives, respectively. Trajectory analysis illustrates that electrostatic neutralization of acidic sidechain residues of GXM is a prerequisite for capsule assembling, followed by formation of intermolecular hydrogen bond networks. Further insight into the assembling mechanism of GXM polysaccharides provides the possibility to develop novel treatment and prevention solutions for cryptococcosis.

Study of the whole genome, methylome and transcriptome of Cordyceps militaris.

The complete genome of Cordyceps militaris was sequenced using single-molecule real-time (SMRT) sequencing technology at a coverage over 300×. The genome size was 32.57 Mb, and 14 contigs ranging from 0.35 to 4.58 Mb with an N50 of 2.86 Mb were assembled, including 4 contigs with telomeric sequences on both ends and an additional 8 contigs with telomeric sequences on either the 5' or 3' end. A methylome database of the genome was constructed using SMRT and m4C and m6A methylated nucleotides, and many unknown modification types were identified. The major m6A methylation motif is GA and GGAG, and the major m4C methylation motif is GC or CG/GC. In the C. militaris genome DNA, there were four types of methylated nucleotides that we confirmed using high-resolution LCMS-IT-TOF. Using PacBio Iso-Seq, a total of 31,133 complete cDNA sequences were obtained in the fruiting body. The conserved domains of the nontranscribed regions of the genome include TATA boxes, which are the initial regions of genome replication. There were 406 structural variants between the HN and CM01 strains, and there were 1,114 structural variants between the HN and ATCC strains.

Myeloid-derived suppressor cells accumulate among myeloid cells contributing to tumor growth in matrix metalloproteinase 12 knockout mice.

Myeloid-derived suppressor cells (MDSCs) are found frequently in patients and mice bearing tumors, which derived from immature myeloid cells. In healthy individuals, immature myeloid cells formed in the bone marrow differentiating to dendritic cells, macrophages and neutrophils. However, it is unclear whether some gene deficiency will lead to MDSCs accumulation in mice without bearing tumor. Here, we observed that MDSCs accumulated in the bone marrow of matrix metalloproteinase 12 knockout mice (MMP12-/- mice) compared with wild type mice (MMP12+/+ mice). And the number of CD4+ cells dramatically decreased, regulatory T cells was up-regulation and MDSCs function were determined. The results suggested that immune surveillance have been impaired in MMP12-/- transgenic mice. After intravenous administration of B16 murine melanoma cells, MMP12-/- mice developed more metastatic pulmonary nodules than MMP12+/+ mice. Meanwhile, more MDSCs appeared in the tumors of MMP12-/- mice compared with those of MMP12+/+ mice. Mechanistically, we performed a MDSC blocking assay, finding that blockade of MDSCs resulted in reducing growth of tumors in MMP12-/- mice. Furthermore, we ascertained that macrophages in MMP12-/- mice abundantly secrete IL-1ß in bone marrow which induce the accumulation of MDSCs in the bone marrow. Together, these results demonstrated that the macrophages in MMP12-/- mice could crosstalk with myeloid cells through IL-1ß, inducing MDSCs accumulation, then contributing to tumor growth. It has revealed that the critical roles of macrophage in myeloid cells differentiation.

Inflammatory Molecule, PSGL-1, Deficiency Activates Macrophages to Promote Colorectal Cancer Growth through NFκB Signaling.

P-selectin glycoprotein ligand 1 (SELPLG/PSGL-1) is an inflammatory molecule that is functionally related to immune cell differentiation and leukocyte mobilization. However, the role of PSGL-1 in tumor development remains unknown. Therefore, this study investigates the mechanistic role of PSGL-1 in the development of intestinal tumors in colorectal cancer. ApcMin/+ mice are highly susceptible to spontaneous intestinal adenoma formation, and were crossbred with PSGL1-null mice to generate compound transgenic mice with a ApcMin/+;PSGL-1-/- genotype. The incidence and pathologic features of the intestinal tumors were compared between the ApcMin/+ mice and ApcMin/+;PSGL-1-/- mice. Importantly, PSGL-1-deficient mice showed increased susceptibility to develop intestinal tumors and accelerated tumor growth. Mechanistically, increased production of the mouse chemokine ligand 9 (CCL9/MIP-1γ) was found in the PSGL-1-deficient mice, and the macrophages are likely the major source of macrophage inflammatory protein-1 gamma (MIP-1γ). Studies in vitro demonstrated that macrophage-derived MIP-1γ promoted colorectal cancer tumor cell growth through activating NFκB signaling. Conversely, restoration of the PSGL-1 signaling via bone marrow transplantation reduced MIP-1γ production and attenuated the ability of ApcMin/+;PSGL-1-/- mice to generate intestinal tumors. In human colorectal cancer clinical specimens, the presence of PSGL-1-positive cells was associated with a favorable tumor-node-metastasis staging and decreased lymph node metastasis.Implications:PSGL-1 deficiency and inflammation render intestinal tissue more vulnerable to develop colorectal tumors through a MIP-1γ/NFκB signaling axis. Mol Cancer Res; 15(4); 467-77. ©2017 AACR.

Lgr5-positive cells in the lung and their clinical significance in patients with lung adenocarcinoma.

Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) is well-characterized as a marker of intestinal stem cells and certain types of tumor stem cells, where positive cells may develop into intestinal epithelial cells or intestinal adenomas. However, the roles of Lgr5 in the lung and in lung tumors remain unclear. An immunohistochemistry (IHC) analysis was performed to detect the expression of Lgr5 in the lung from a normal mouse. Histopathological sections of the lungs from Lgr5 heterozygous knockout mice (Lgr5+/-) were observed following with hematoxylin and eosin. Furthermore, tissue microarrays containing tumor cores from lung cancer patients were also analyzed by IHC. Lgr5-positive cells were present in the pulmonary alveoli and bronchi of normal mice, whereas the lungs of Lgr5+/- mice lost their normal morphological structure compared with the lungs of the normal mice. Lgr5 was expressed in lung adenocarcinoma, however, not in squamous carcinoma, and Lgr5 expression was positively associated with tumor, node, metastasis stage. Lgr5 is expressed in normal murine lung and is associated with TNM stage in patients with lung adenocarcinoma.