ACE2 and Furin Expressions in Oral Epithelial Cells Possibly Facilitate COVID-19 Infection via Respiratory and Fecal-Oral Routes.

Background: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that mainly transfers from human to human via respiratory and gastrointestinal routes. The S-glycoprotein in the virus is the key factor for the entry of SARS-CoV-2 into the cell, which contains two functional domains: S1 is an angiotensin-converting enzyme 2 (ACE2) receptor binding domain, and S2 is necessary for fusion of the coronavirus and cell membranes. Moreover, it has been reported that ACE2 is likely to be the receptor for SARS-CoV-2. In addition, mRNA level expression of Furin enzyme and ACE2 receptor had been reported in airway epithelia, cardiac tissue, and enteric canals. However, the expression patterns of ACE2 and Furin in different cell types of oral tissues are still unclear. Methods: In order to investigate the potential infective channel of the new coronavirus via the oropharyngeal cavity, we analyze the expression of ACE2 and Furin in human oral mucosa using the public single-cell sequence datasets. Furthermore, immunohistochemistry was performed in mucosal tissue from different oral anatomical sites to confirm the expression of ACE2 and Furin at the protein level. Results: The bioinformatics results indicated the differential expression of ACE2 and Furin on epithelial cells from different oral anatomical sites. Immunohistochemistry results revealed that both the ACE2-positive and Furin-positive cells in the target tissues were mainly positioned in the epithelial layers, partly expressed in fibroblasts, further confirming the bioinformatics results. Conclusions: Based on these findings, we speculated that SARS-CoV-2 could invade oral mucosal cells through two possible routes: binding to the ACE2 receptor and fusion with cell membrane activated by Furin protease. Our results indicated that oral mucosa tissues are susceptible to SARS-CoV-2 that could facilitate COVID-19 infection via respiratory and fecal-oral routes.

Erratum: Andrographolide Suppress Tumor Growth by Inhibiting TLR4/NF-κB Signaling Activation in Insulinoma: Erratum.

[This corrects the article DOI: 10.7150/ijbs.7723.].

Generation and Biological Characteristics of a Mouse Model of Breast Cancer that Copresents with Diabetes Mellitus.

Both diabetes and breast cancer are common diseases worldwide, and diabetes is also linked to higher rates of breast cancer. Epidemiological data also indicate that diabetes may be one of the risk factors for breast cancer. However, the effect of diabetes on breast cancer progression in vivo is rarely reported. We established an ideal animal model of breast cancer using transgenic MMTV-PyMT mice, which spontaneously developed breast cancer. In this model, the animals copresented with diabetes mellitus, which allowed us to study the effect of high glucose on breast cancer. Compared with MMTV-PyMT mice without diabetes, MMTV-PyMT mice with diabetes developed heavier tumors and exhibited greater tumor volumes. Furthermore, high glucose promoted the invasiveness and metastasis of breast cancer in MMTV-PyMT mice. This breast cancer model in which mice copresented with diabetes provides a useful tool to study the effect of diabetes on breast cancer. Anat Rec, 302:269-277, 2019. © 2018 Wiley Periodicals, Inc.

Dipalmitoylphosphatidic acid inhibits tumor growth in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis, accounting for approximately 12-24% of breast cancer cases. Accumulating evidence has indicated that there is no effective targeted therapy available for TNBC. Dipalmitoylphosphatidic acid (DPPA) is a bioactive phospholipid. However, the function of DPPA in the growth of TNBC has not yet been studied. In this study, we employed TNBC cells and a subcutaneous tumor model to elucidate the possible effect of DPPA on tumor growth in TNBC. We showed that DPPA significantly inhibited tumor growth in the mouse subcutaneous tumor model and suppressed cell proliferation and angiogenesis in TNBC tumor tissues. This inhibition was mediated partly by suppressing the expression of cyclin B1 (CCNB1), which directly promoted the accumulation of cells in the G2 phase and arrested cell cycle progression in human TNBC. In addition, the inhibition of tumor growth by DPPA may also be mediated by the suppression of tumor angiogenesis in TNBC. This work provides initial evidence that DPPA might be vital as an anti-tumor drug to treat TNBC.

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.

CD11b deficiency suppresses intestinal tumor growth by reducing myeloid cell recruitment.

Mac-1 (CD11b) is expressed on bone marrow-derived immune cells. CD11b binds to ligands to regulate leukocyte adhesion and migration across the endothelium or epithelium. Here, we employed CD11b knockout mice and an Apc(Min/+) spontaneous intestinal adenoma mouse model to clarify the function of CD11b in intestinal tumorigenesis. We showed that CD11b deficiency may contribute to the inhibition of myeloid cell trafficking to the tumor microenvironment and inactivated Wnt/ß-catenin pathway to suppress tumor growth. This effect was partly mediated by inhibiting the myeloid cell-mediated decrease in TNF-α secretion, which inhibits the recruitment of myeloid-derived suppressor cells to the tumor microenvironment and subsequently induces IFN-γ and CXCL9 production. This work provides evidence for the mechanism by which CD11b may function as an important oncogene and highlights the potential of CD11b as a therapeutic target in CRC.

SRF-miR­29b-MMP2 axis inhibits NSCLC invasion and metastasis.

MicroRNAs play key roles in tumour metastasis. miR­29b was previously reported to act as a tumour suppressor or an oncogene in diverse cancers. However, its accurate function and mechanism in metastasis of no-small cell lung cancer (NSCLC) are not well known. In this study, we describe the function of miR­29b in NSCLC metastasis and its regulatory mechanisms. We found that miR­29b is downregulated in high-metastatic NSCLC cells and low-expression of miR­29b in primary NSCLC tissue was correlated with lymph node metastasis. Both gain- and loss-of-function study indicated overexpression of miR­29b could suppress migration and invasion abilities of high-metastatic NSCLC cells, while downregulation of miR­29b expression promoted migration and invasion of low-metastatic NSCLC cells in vitro. Moreover, introduction of miR­29b inhibited high­metastatic NSCLC cells, in vivo, metastasis to liver and lungs. Mechanistically, miR­29b, induced by the transcription factor SRF, posttranscriptionally downregulates MMP2 expression by directly targeting its 3'-untranslated regions. These findings indicate a new regulatory mode, whereby miR­29b, which is inhibited by its upstream transcription factor SRF, was able to promote its direct target MMP2 leading to NSCLC invasion and metastasis.

Slit2/Robo1 signaling promotes intestinal tumorigenesis through Src-mediated activation of the Wnt/ß-catenin pathway.

Slit2 is often overexpressed in cancers. Slit2 is a secreted protein that binds to Roundabout (Robo) receptors to regulate cell growth and migration. Here, we employed several complementary mouse models of intestinal cancers, including the Slit2 transgenic mice, the ApcMin/+ spontaneous intestinal adenoma mouse model, and the DMH/DSS-induced colorectal carcinoma model to clarify function of Slit2/Robo1 signaling in intestinal tumorigenesis. We showed that Slit2 and Robo1 are overexpressed in intestinal tumors and may contribute to tumor generation. The Slit2/Robo1 signaling can induce precancerous lesions of the intestine and tumor progression. Ectopic expression of Slit2 activated Slit2/Robo1 signaling and promoted tumorigenesis and tumor growth. This was mediated in part through activation of the Src signaling, which then down-regulated E-cadherin, thereby activating Wnt/ß-catenin signaling. Thus, Slit2/Robo1 signaling is oncogenic in intestinal tumorigenesis.

Increased permeability of the blood-brain barrier and Alzheimer's disease-like alterations in slit-2 transgenic mice.

Alzheimer's disease (AD) is a progressive neurological disorder that primarily affects memory, and its prevalence is rising. Increasing evidence suggests that dysfunction of the blood-brain barrier (BBB) may be involved in AD and other neurodegenerative diseases. Herein, we report that the permeability of the BBB is increased and that AD-like alterations are present in Slit-2 overexpressing transgenic mice. We found that behavioral change and the corresponding molecular diagnostic markers of AD, such as hippocampal neuron apoptosis, amyloid-ß (Aß) protein deposition, and acetylcholinesterase expression, were increased in the Slit-2 transgenic mice. Moreover, the endothelial cells were dysfunctional, the size of the lateral ventricle cavity increased, and the permeability of the BBB increased. Additionally, there was an increased serum level of glutamate indicating that the BBB is related to AD. Finally, histopathological analysis of other organs in the Slit-2 overexpressing mice did not show any marked abnormalities. These findings demonstrate that Slit2 overexpression may be responsible for AD-like alterations and the increased BBB permeability in these mice. Our study provides a potential novel mechanism for the development of AD.

Andrographolide inhibits melanoma tumor growth by inactivating the TLR4/NF-κB signaling pathway.

The TLR4/NF-κB signaling pathway plays a critical role in tumor progression. Andrographolide (Andro) has been reported to have anticancer activity in multiple types of cancer. However, the pharmacological activities of Andro in melanoma are not completely understood. In this study, we defined the anticancer effects of Andro in melanoma and elucidated its potential mechanisms of action. Our experiments showed that Andro significantly inhibited melanoma tumor growth and metastasis by inducing cell cycle arrest and apoptosis. In addition, Andro significantly inhibited the TLR4/NF-κB signaling pathway. Furthermore, the inactivation of TLR4/NF-κB signaling inhibited the mRNA and protein expression of CXCR4 and Bcl-6, which are antitumor genes. This work provides evidence that the TLR4/NF-κB signaling pathway is a potential therapeutic target and may also be indispensable in the Andro-mediated anticancer effect in melanoma.

Andrographolide suppress tumor growth by inhibiting TLR4/NF-κB signaling activation in insulinoma.

Insulinomas are rare tumors, and approximately 10% of insulinomas are malignant. Accumulating evidence has implicated that we still lack effective therapy to treat the patients who are diagnosed with rare malignant insulinoma. Previous studies have reported that Andrographolide (Andro) could inhibit cell cycle progression, reduce cell invasion and induce cell apoptosis in many common cancer cells. However, the effects of andro are cell type-dependent. So we emplored the ß-TC-6 cells and the RIP1-Tag2 transgenic mouse model of endogenously growing insulinoma model to elucidate the possible anti-cancer effect of Andro on insulinoma, an uncommon type of malignant cancers in this study. Our experiments revealed that Andro significantly inhibited tumor growth at both the early-stage and the advanced-stage of insulinoma through targeting the TLR4/NF-κB signaling pathway. This work initially provides the evidence that the TLR4/NF-κB signaling pathway might be vital as a potential therapeutic target, and also indispensable in Andro-mediated anti-cancer effect in insulinoma.

P-selectin-mediated platelet adhesion promotes the metastasis of murine melanoma cells.

Studies have indicated that the aggregation of activated platelets with cancer cells facilitates tumor metastasis; the adhesion molecule P-selectin may be an important mediator of this process, but the detailed mechanism is unclear. In the current study, we established a B16F10 (B16) cell metastatic model in P-selectin knockout (P-sel-/-) mice to determine the effect of P-selectin-mediated platelet adhesion on metastasis. Compared with C57 mice, P-sel-/- mice developed fewer metastatic foci, and cell proliferation within the metastatic tumors was inhibited by P-selectin deficiency. The platelet refusion assay demonstrated that mice with P-sel-/- platelets developed fewer lung metastatic foci (P<0.01) with a lower microvascular density (MVD) than mice with wild-type platelets. A co-culture model of platelets and B16 cells was utilized to determine the difference in VEGF concentration in the supernatants. The results demonstrated that the supernatant from the P-sel-/- platelet/B16 co-culture had a lower concentration of VEGF. Therefore, our findings indicated that P-selectin deficiency inhibited the metastasis of B16 cells and that wild-type platelet refusion reversed this inhibition. The P-selectin-mediated interaction between platelets and B16 cells promoted angiogenesis by up-regulating VEGF.

Micrometastasis expressing insulin arise in lung and spleen at advanced stage of rip1-tag2 transgenic mice.

Rip1-Tag2 mice is one overt pancreatic ß-cell tumor model, which is widely used for studying pancreas tumor angiogenesis and tumor development. However, tumor metastasis in Rip1-Tag2 mice had rarely been reported, in this present study, we find some micrometastasis in lung and spleen of the Rip1-Tag2 mice at advanced stage, which is important for uncovering metastasis cell characteristics and exploring how to survive in cancer microenvironment. To study the micrometastasis of Rip1-Tag2 mice in advanced pancreatic cancer, we first observed the pathology process of ß cell tumor in Rip1-Tag2 mice through HE staining, then we performed immunohistochemistry with insulin antibody, T-antigen antibodies and C-petide antibody on lung and spleen tissues sections from advanced stage, comparing with background wild-type C57BL/6 mice sections. The results indicated that micrometastasis expressing insulin was found in the Rip1-Tag2 mice lung, and spleen. Further evidences demonstrate pathology structure of lung and spleen are damaged. Interestingly and importantly, the expression of T antigen and insulin antibodies are all decreased in advanced stage of primary ß cell tumor, which suggest that the at least partly micrometastasis is derived from the early stage or from advanced stage of ß cell tumor then return to undifferentiated state like cancer stem cell. The findings contributed to the study of cancer metastasis and cancer stem cell.

A novel four-step system for screening angiogenesis inhibitors.

Angiogenesis exhibits a significant effect on tumor progression. Inhibiting angiogenesis may provide significant advantages over currently available therapeutics for cancer therapies thus, the development of a system of screening angiogenesis is essential. In the present study, a novel available system of screening angiogenesis inhibitors by four steps was developed. The chorioallantoic membrane (CAM), yolk sac membrane and early chick embryo blood island assay were initially performed to obtain possible antitumor compounds. The MMTV­PyMT transgenic breast cancer mouse model was used for final screening and to confirm potential antitumor effects. Four angiogenesis inhibitors were isolated from 480 compounds, which were obtained from ICCB known bioactives library, by a combination of the CAM, yolk sac membrane and early chick embryo blood island assay. The MMTV­PyMT mouse was treated with one of four agents and it was demonstrated that the tumor volume was significantly inhibited. These results demonstrate that the four­step screening system is feasible.

Coaction of spheroid-derived stem-like cells and endothelial progenitor cells promotes development of colon cancer.

Although some studies described the characteristics of colon cancer stem cells (CSCs) and the role of endothelial progenitor cells (EPCs) in neovascularization, it is still controversial whether an interaction exists or not between CSCs and EPCs. In the present study, HCT116 and HT29 sphere models, which are known to be the cells enriching CSCs, were established to investigate the roles of this interaction in development and metastasis of colon cancer. Compared with their parental counterparts, spheroid cells demonstrated higher capacity of invasion, higher tumorigenic and metastatic potential. Then the in vitro and in vivo relationship between CSCs and EPCs were studied by using capillary tube formation assay and xenograft models. Our results showed that spheroid cells could promote the proliferation, migration and tube formation of EPCs through secretion of vascular endothelial growth factor (VEGF). Meanwhile, the EPCs could increase tumorigenic capacity of spheroid cells through angiogenesis. Furthermore, higher microvessel density was detected in the area enriching cancer stem cells in human colon cancer tissue. Our findings indicate that spheroid cells possess the characteristics of cancer stem cells, and the coaction of CSCs and EPCs may play an important role in the development of colon cancer.

Laparoscopic versus open gastrectomy with D2 lymph node dissection for gastric cancer: a meta-analysis.

BACKGROUND: Nowadays laparoscopic gastrectomy with D2 lymph node dissection (LGD2) is used for gastric cancer, which provides an alternative to open radical gastrectomy (OGD2). But it has not gained wide acceptance, and its oncological safety remains controversial. The aim of this study is to evaluate the efficiency and safety of LGD2 through a meta-analysis. MATERIALS AND METHODS: Original articles of clinical trials comparing LGD2 and OGD2 for gastric cancer, published in English language from January 2001 to April 2010 were searched in the MEDLINE, Current Contents, and Pubmed. Strict literature appraisal and data extraction were carried out independently by 2 reviewers and then a meta-analysis was performed using RevMan 4.2.5 to evaluate the items of operative time, blood loss, harvested lymph nodes, analgesic medication, first flatus day, postoperative hospital stay, postoperative complications, and cumulative survival rate. RESULTS: Ten trials were involved in the meta-analysis, concerning a total of 1039 patients (495 in LGD2 and 544 in OGD2). Compared with OGD2, LGD2 showed advantages of less blood loss during operation [weighed mean difference (WMD), -114.98; 95% confidence interval (CI), -160.44 to -69.52; P<0.00001], less postoperative pain (WMD, -0.89; 95% CI, -1.54 to -0.32; P=0.002), earlier passage of flatus (WMD, -0.84; 95% CI, -1.25 to -0.43; P<0.0001), shorter hospital stay (WMD, -3.27; 95% CI, -4.54 to -2.00; P<0.00001), and less postoperative complications [odds ratio (OR), 0.56; 95% CI, 0.32-0.59; P=0.03]; but with longer operative time [WMD, 57.14; 95% CI, 38.12-76.15; P<0.00001]. There were no significant differences between LGD2 and OGD2 in harvested lymph nodes (WMD, -2.07; 95% CI, -4.27 to -0.14; P=0.07) and overall survival rate of 11 to 60 months' follow-up (OR, 1.44; 95% CI, 0.92-2.27; P=0.11). CONCLUSIONS: The results of this meta-analysis suggest that LGD2 results in less blood loss and postoperative complications and also less pain and faster bowel function recovery, with similar harvested lymph nodes and overall survival rate comparing to OGD2. However, we also see the need for further high-quality randomized controlled trials comparing the 2 procedures.

[Effect of a selective inducible nitric oxide synthase inhibitor on cell growth in human colorectal cancer Lovo cell line].

OBJECTIVE: To investigate the effect of a selective inducible nitric oxide synthase(iNOS) inhibitor, aminoguanidine (AG), on the proliferation and apoptosis of human colorectal cancer (CRC) Lovo cell line, and explore its possible mechanism. METHODS: MTT assay was used to detect the inhibition of Lovo cell growth by aminoguanidine. Apoptosis and cell cycle of Lovo cells were examined by flow cytometry (FCM). Morphologic change of Lovo cell treated by AG was observed with AO/EB staining. RESULTS: There were significant differences in 0.5 mmol/L and 1.0 mmol/L AG groups as compared to the control group (P<0.05). The absorbance (A) values of Lovo cells in each time point were significantly different (P<0.05). Growth of Lovo cells was inhibited by aminoguanidine in a dose- and time-dependent manner. FCM analysis showed that the cell ratio of G(0)/G(1) phase increased with the increasing of the concentration of aminoguanidine, but the cell ratio of S-and G(2)/M phase decreased correspondingly (P<0.05). S phase fraction and proliferation index (PI) decreased remarkably, and the apoptotic rate of Lovo cells increased. After AG treatment, AO/EB staining revealed some apoptotic morphological features such as cell shrinkage, nuclear condensation, DNA fragmentation, and formation of apoptosis bodies. CONCLUSIONS: Aminoguanidine inhibits the proliferation and facilitates the apoptosis of human CRC Lovo cells. One of the mechanisms may be explained as blocking the progress of cell cycle of CRC Lovo cells by aminoguanidine.

[Advances in study on anti-tumor mechanism of andrographolide].

In recent years, more and more attention was payed to the study of andrographolide. Andrographolide has the extensive pharmacological actions, such as anti-tumor, dephlogisticate and antibiosis and anti-virus. It was dected that andrographolide had the action of anti-tumor in gastric cancer, liver cancer, lung cancer and breast cancer. The anti-tumor mechanism of andrographolide was versatile, for instance, andrographolide can induce the apoptosis of cancer cell, inhibit the cell cycle, and increase the antitumor activity of lymphocyte. The following review was about the recent progress of study on the anti-tumor mechanism of andrographolide.