Yanqing Ding

The clinical pathology of severe acute respiratory syndrome (SARS): a report from China

In order to investigate the clinical pathology of severe acute respiratory syndrome (SARS), the autopsies of three patients who died from SARS in Nan Fang Hospital Guangdong, China were studied retrospectively. Routine haematoxylin and eosin (H&E) staining was used to study all of the tissues from the three cases. The lung tissue specimens were studied further with Macchiavello staining, viral inclusion body staining, reticulin staining, PAS staining, immunohistochemistry, ultrathin sectioning and staining, light microscopy, and transmission electron microscopy. The first symptom was hyperpyrexia in all three cases, followed by progressive dyspnoea and lung field shadowing. The pulmonary lesions included bilateral extensive consolidation, localized haemorrhage and necrosis, desquamative pulmonary alveolitis and bronchitis, proliferation and desquamation of alveolar epithelial cells, exudation of protein and monocytes, lymphocytes and plasma cells in alveoli, hyaline membrane formation, and viral inclusion bodies in alveolar epithelial cells. There was also massive necrosis of splenic lymphoid tissue and localized necrosis in lymph nodes. Systemic vasculitis included oedema, localized fibrinoid necrosis, and infiltration of monocytes, lymphocytes, and plasma cells into vessel walls in the heart, lung, liver, kidney, adrenal gland, and the stroma of striated muscles. Thrombosis was present in small veins. Systemic toxic changes included degeneration and necrosis of the parenchyma cells in the lung, liver, kidney, heart, and adrenal gland. Electron microscopy demonstrated clusters of viral particles, consistent with coronavirus, in lung tissue. SARS is a systemic disease that injures many organs. The lungs, immune organs, and systemic small vessels are the main targets of virus attack, so that extensive consolidation of the lung, diffuse alveolar damage with hyaline membrane formation, respiratory distress, and decreased immune function are the main causes of death. Copyright

Organ distribution of severe acute respiratory syndrome (SARS) associated coronavirus (SARS‐CoV) in SARS patients: implications for pathogenesis and virus transmission pathways

We previously identified the major pathological changes in the respiratory and immune systems of patients who died of severe acute respiratory syndrome (SARS) but gained little information on the organ distribution of SARS‐associated coronavirus (SARS‐CoV). In the present study, we used a murine monoclonal antibody specific for SARS‐CoV nucleoprotein, and probes specific for a SARS‐CoV RNA polymerase gene fragment, for immunohistochemistry and in situ hybridization, respectively, to detect SARS‐CoV systematically in tissues from patients who died of SARS. SARS‐CoV was found in lung, trachea/bronchus, stomach, small intestine, distal convoluted renal tubule, sweat gland, parathyroid, pituitary, pancreas, adrenal gland, liver and cerebrum, but was not detected in oesophagus, spleen, lymph node, bone marrow, heart, aorta, cerebellum, thyroid, testis, ovary, uterus or muscle. These results suggest that, in addition to the respiratory system, the gastrointestinal tract and other organs with detectable SARS‐CoV may also be targets of SARS‐CoV infection. The pathological changes in these organs may be caused directly by the cytopathic effect mediated by local replication of the SARS‐CoV; or indirectly as a result of systemic responses to respiratory failure or the harmful immune response induced by viral infection. In addition to viral spread through a respiratory route, SARS‐CoV in the intestinal tract, kidney and sweat glands may be excreted via faeces, urine and sweat, thereby leading to virus transmission. This study provides important information for understanding the pathogenesis of SARS‐CoV infection and sheds light on possible virus transmission pathways. This data will be useful for designing new strategies for prevention and treatment of SARS. Copyright

Emerging roles of circRNA_001569 targeting miR-145 in the proliferation and invasion of colorectal cancer.

Circular RNAs (circRNAs), a large class of RNAs, have recently shown huge capabilities as gene regulators in mammals. Some of them bind with microRNAs (miRNAs) and act as natural miRNA sponges to inhibit related miRNAs’ activities. Here we showed that hsa_circ_001569 acted as a positive regulator in cell proliferation and invasion of colorectal cancer (CRC). Moreover, hsa_circ_001569 was identified as a sponge of miR-145 and up-regulated miR-145 functional targets E2F5, BAG4 and FMNL2. In CRC tissues, circ_001569 negatively correlated with miR-145, and miR-145 correlated negatively with E2F5, BAG4 and FMNL2 expressions. Our study reveals a novel regulatory mechanism of circ_001569 in cell proliferation and invasion in CRC, provides a comprehensive landscape of circ_001569 that will facilitate further biomarker discoveries in the progression of CRC.

HOXB7 as a Prognostic Factor and Mediator of Colorectal Cancer Progression

Purpose: This study was to investigate the clinicopathologic significance and potential role of HOXB7 in the development and progression of colorectal cancer (CRC). Experimental Design: The relationship between HOXB7 expression and clinical characteristics of CRC was analyzed in 224 paraffin-embedded archived CRC specimens by immunohistochemistry (IHC). The effects of HOXB7 on cell growth and proliferation, as well as on tumorigenesis, were examined both in vitro and in vivo, using MTT assay, colony formation assay, cell cycle analysis, soft agar assay, and tumorigenesis in nude mice. Western blotting and real-time reverse transcriptase-PCR were performed to examine the impact of HOXB7 on the PI3K/Akt and MAPK signaling pathways. Results: HOXB7 protein level was significantly correlated with advanced Dukes stage (P < 0.001), T stage (P = 0.012), distant metastasis (P = 0.042), higher proliferation index (P = 0.007) and poor survival of patients (P = 0.005). Enforced expression of HOXB7 in CRC cell lines significantly enhanced cell growth, proliferation and tumorigenesis. Conversely, knockdown of HOXB7 caused an inhibition of cell growth, proliferation, and tumorigenesis. We also showed that HOXB7 accelerated G0–G1 to S-phase transition concomitantly with upregulation of cyclin D1 and downregulation of p27Kip1. On the contrary, knockdown of HOXB7 caused G1–S-phase arrest, downregulation of cyclin D1 and upregulation of p27Kip1. Enforced expression of HOXB7 could enhance PI3K/AKT and MAPK pathway activity. Conclusion: Our findings suggest that HOXB7 protein, as a valuable marker of CRC prognosis, plays an important role in the development and progression of human CRC. Clin Cancer Res; 17(11); 3569–78. ©2011 AACR.

MicroRNA-30b functions as a tumour suppressor in human colorectal cancer by targeting KRAS, PIK3CD and BCL2

Colorectal cancer (CRC) is the third most common cancer in the USA. MicroRNAs play important roles in the pathogenesis of CRC. In this study, we investigated the role of miR‐30b in CRC and found that its expression was significantly lower in CRC tissues than that in normal tissues. We showed that a low expression level of miR‐30b was closely related to poor differentiation, advanced TNM stage and poor prognosis of CRC. Further experiments showed that over‐expression of miR‐30b suppressed CRC cell proliferation in vitro and tumour growth in vivo. Specifically, miR‐30b promoted G1 arrest and induced apoptosis. Moreover, KRAS, PIK3CD and BCL2 were identified as direct and functional targets of miR‐30b. MiR‐30b directly targeted the 3′‐untranslated regions of their mRNAs and repressed their expression. This study revealed functional and mechanistic links between miRNA‐30b and oncogene KRAS, PIK3CD and BCL2 in the pathogenesis of CRC. MiR‐30b not only plays important roles in the regulation of cell proliferation and tumour growth in CRC, but is also a potential prognostic marker or therapeutic target for CRC. Restoration of miR‐30b expression may represent a promising therapeutic approach for targeting malignant CRC. Copyright

microRNA-224 Promotes Cell Proliferation and Tumor Growth in Human Colorectal Cancer by Repressing PHLPP1 and PHLPP2

Purpose: To investigate the clinicopathologic significance, role, and mechanism of action of microRNA-224 (miR-224) in colorectal cancer. Experimental Design: Real-time PCR was used to quantify miR-224 expression. The association of miR-224 with the clinicopathologic features and survival was evaluated in 110 colorectal cancer patients. The role of miR-224 in colorectal cancer was investigated using in vitro and in vivo assays. Luciferase reporter assays were conducted to confirm target gene associations. Results: miR-224 was overexpressed in colorectal cancer. High-level expression of miR-224 was significantly associated with an aggressive phenotype and poor prognosis. Overexpression of miR-224 promoted colorectal cancer cell proliferation in vitro and tumor growth in vivo. Specifically, miR-224 accelerated the G1–S phase transition through activation of AKT/FOXO3a signaling, downregulation of p21Cip1 and p27Kip1, and upregulation of cyclin D1. Moreover, both PH domain leucine-rich-repeats protein phosphatase 1 (PHLPP1) and PHLPP2, antagonists of PI3K/AKT signaling, were confirmed as bona fide targets of miR-224. miR-224 directly targeted the 3′-untranslated regions of the PHLPP1 and PHLPP2 mRNAs and repressed their expression. Conclusion: This study reveals functional and mechanistic links between miRNA-224 and the tumor suppressors PHLPP1 and PHLPP2 in the pathogenesis of colorectal cancer. miR-224 not only plays important roles in the regulation of cell proliferation and tumor growth in colorectal cancer, but also has potential as a prognostic marker or therapeutic target for colorectal cancer. Clin Cancer Res; 19(17); 4662–72. ©2013 AACR.

MiR-141 Suppresses the Migration and Invasion of HCC Cells by Targeting Tiam1

Background We have demonstrated that T lymphoma invasion and metastasis 1 (Tiam1) gene is associated with the poor prognosis of patients with hepatocellular carcinoma (HCC), and we used a computational approach to identify miR-141 as a Tiam1-targeting microRNA (miRNA). Here, we explored the function of miR-141 and the relationship between miR-141 and Tiam1 gene in HCC. Methods The miR-141 expression in HCC tissues and cell lines was detected and its roles in regulation of HCC cell proliferation, migration and invasion and target gene expression was investigated. Tiam1 was identified as a novel target of miR-141. Ethics statement: our study was approved by the Nanfang Hospital Medical Ethics Committee Ethics statement. Written informed consent was obtained before collection. Results Based on in situ hybridization (ISH) analysis, miR-141 was down-regulated in the same HCC samples. Kaplan-Meier analysis demonstrated that patients with low miR-141 expression had poorer overall survival rate than that of the patients with high miR-141 expression. Furthermore, multivariate Cox regression analysis indicated that miR-141 could serve as an independent prognostic factor in HCC. MiR-141 significantly inhibited in vitro cell proliferation, migration and invasion as proved by gain- and loss- of function studies, while the mRNA and protein levels of Tiam1 were reduced in cells over-expressing miR-141. Moreover, Tiam1 treatment antagonized this effect, while knockdown of Tiam1 by Tiam1 short hairpin RNA (shTiam1) induced inhibitory effects. Conclusions These findings indicated that miR-141 functions as a tumor suppressor and inhibits the migration and invasion of HCC cells by targeting Tiam1, which may provide novel prognostic and treatment strategies for HCC patients.

Nuclear factor-κB modulates osteogenesis of periodontal ligament stem cells through competition with β-catenin signaling in inflammatory microenvironments

Inflammation can influence multipotency and self-renewal of mesenchymal stem cells (MSCs), resulting in their awakened bone-regeneration ability. Human periodontal ligament tissue-derived MSCs (PDLSCs) have been isolated, and their differentiation potential was found to be defective due to β-catenin signaling indirectly regulated by inflammatory microenvironments. Nuclear factor-κB (NF-κB) is well studied in inflammation by many different groups. The role of NF-κB needs to be studied in PDLSCs, although genetic evidences have recently shown that NF-κB inhibits osteoblastic bone formation in mice. However, the mechanism as to how inflammation leads to the modulation of β-catenin and NF-κB signaling remains unclear. In this study, we investigated β-catenin and NF-κB signaling through regulation of glycogen synthase kinase 3β activity (GSK-3β, which modulates β-catenin and NF-κB signaling) using a specific inhibitor LiCl and a phosphatidylinositol 3-kinase (PI3K) inhibitor LY 294002. We identified that NF-κB signaling might be more important for the regulation of osteogenesis in PDLSCs from periodontitis compared with β-catenin. BAY 11-7082 (an inhibitor of NF-κB) could inhibit phosphorylation of p65 and partly rescue the differentiation potential of PDLSCs in inflammation. Our data indicate that NF-κB has a central role in regulating osteogenic differentiation of PDLSCs in inflammatory microenvironments. Given the molecular mechanisms of NF-κB in osteogenic differentiation governed by inflammation, it can be said that NF-κB helps in improving stem cell-mediated inflammatory bone disease therapy.

Elevated MicroRNA-31 Expression Regulates Colorectal Cancer Progression by Repressing Its Target Gene SATB2

Several studies have brought about increasing evidence to support the hypothesis that miRNAs play a pivotal role in multiple processes of carcinogenesis, including cell growth, apoptosis, differentiation, and metastasis. In this study, we investigated the potential role of miR-31 in colorectal cancer (CRC) aggressiveness and its underlying mechanisms. We found that miR-31 increased in CRC cells originated from metastatic foci and human primary CRC tissues with lymph node metastases. Furthermore, the high-level expression of miR-31 was significantly associated with a more aggressive and poor prognostic phenotype of patients with CRC (p < 0.05). The stable over-expression of miR-31 in CRC cells was sufficient to promote cell proliferation, invasion, and migration in vitro. It facilitated tumor growth and metastasis in vivo too. Further studies showed that miR-31 can directly bind to the 3’untranslated region (3’UTR) of SATB2 mRNA and subsequently repress both the mRNA and protein expressions of SATB2. Ectopic expression of SATB2 by transiently transfected with pCAG-SATB2 vector encoding the entire SATB2 coding sequence could reverse the effects of miR-31 on CRC tumorigenesis and progression. In addition, ectopic over-expression of miR-31 in CRC cells induced epithelial-mesenchymal transition (EMT). Our results illustrated that the up-regulation of miR-31 played an important role in CRC cell proliferation, invasion, and metastasis in vitro and in vivo through direct repressing SATB2, suggesting a potential application of miR-31 in prognosis prediction and therapeutic application in CRC.

LIM and SH3 Protein 1 Induces TGFβ-Mediated Epithelial–Mesenchymal Transition in Human Colorectal Cancer by Regulating S100A4 Expression

Purpose: The expression of LIM and SH3 protein 1 (LASP1) was upregulated in colorectal cancer cases, thereby contributing to the aggressive phenotypes of colorectal cancer cells. However, we still cannot decipher the underlying molecular mechanism associated with colorectal cancer metastasis. Experimental Design: In this study, IHC was performed to investigate the expression of proteins in human colorectal cancer tissues. Western blot analysis was used to assess the LASP1-induced signal pathway. Two-dimensional difference gel electrophoresis was performed to screen LASP1-modulated proteins and uncover the molecular mechanism of LASP1. TGFβ was used to induce an epithelial–mesenchymal transition (EMT). Results: LASP1 expression was correlated with the mesenchymal marker vimentin and was inversely correlated with epithelial markers, namely, E-cadherin and β-catenin, in clinical colorectal cancer samples. The gain- and loss-of-function assay showed that LASP1 induces EMT-like phenotypes in vitro and in vivo. S100A4, identified as a LASP1-modulated protein, was upregulated by LASP1. Moreover, it is frequently coexpressed with LASP1 in colorectal cancer. S100A4 was required for EMT, and an increased cell invasiveness of colorectal cancer cell is induced by LASP1. Furthermore, the stimulation of TGFβ resulted in an activated Smad pathway that increased the expression of LASP1 and S100A4. The depletion of LASP1 or S100A4 expression inhibited the TGFβ signaling pathway. Moreover, it significantly weakened the proinvasive effects of TGFβ on colorectal cancer cells. Conclusion: These findings elucidate the central role of LASP1 in the TGFβ-mediated EMT process and suggest a potential target for the clinical intervention in patients with advanced colorectal cancer. Clin Cancer Res; 20(22); 5835–47. ©2014 AACR.