Optimization and Biodistribution of [(11)C]-TKF, An Analog of Tau Protein Imaging Agent [(18)F]-THK523.

The quantification of neurofibrillary tangles (NFTs) using specific PET tracers can facilitate the diagnosis of Alzheimer's disease (AD) and allow monitoring of disease progression and treatment efficacy. [(18)F]-THK523 has shown high affinity and selectivity for tau pathology. However, its high retention in white matter, which makes simple visual inspection difficult, may limit its use in research or clinical settings. In this paper, we optimized the automated radiosynthesis of [(11)C]-TKF and evaluated its biodistribution and toxicity in C57 mice. [(11)C]-TKF can be made by reaction precursor with [(11)C]MeOTf or (11)CH3I, but [(11)C]MeOTf will give us higher labeling yields and specific activity. [(11)C]-TKF presented better brain uptake in normal mouse than [(18)F]-THK523 (3.23% ± 1.25% ID·g(-1) vs. 2.62% ± 0.39% ID·g(-1) at 2 min post-injection). The acute toxicity studies of [(11)C]-TKF were unremarkable.

miR-375 inhibits the invasion and metastasis of colorectal cancer via targeting SP1 and regulating EMT-associated genes.

Accumulating evidence has shown that aberrantly expressed microRNAs (miRNAs) are associated with tumor development and progression. Our previous study found that microRNA-375 (miR-375) was downregulated in colorectal cancer (CRC), but little is known concerning the role of miR-375 and the related mechanism in CRC development. The proliferation, invasion and migration effects were investigated by Cell Counting Kit-8 (CCK-8), colony formation and Transwell assays with or without Matrigel. In addition, candidate target genes were screened and validated by luciferase reporter and western blot assays. In addition, western blot analysis was performed to explore the molecular mechanisms associated with epithelial­mesenchymal transition (EMT). It was found that miR-375 inhibited proliferation, invasion and migration in DLD1 and HCT8 cells. In addition, miR-375 negatively regulated Sp1 transcription factor (SP1) protein by directly binding to the 3'-untranslated region (3'-UTR). Furthermore, it was found that miR-375 regulated matrix metalloproteinase 2 (MMP2) and EMT-associated genes, E-cadherin, vimentin, snail, N-cadherin and ß-catenin. In conclusion, miR-375 inhibited the proliferation, invasion and migration by directly targeting SP1 and regulating MMP2 and EMT-associated genes.

Human adipose-derived mesenchymal progenitor cells engraft into rabbit articular cartilage.

Mesenchymal stem cells (MSCs) are known to have the potential for articular cartilage regeneration, and are suggested for the treatment of osteoarthritis (OA). Here, we investigated whether intra-articular injection of xenogeneic human adipose-derived mesenchymal progenitor cells (haMPCs) promoted articular cartilage repair in rabbit OA model and engrafted into rabbit articular cartilage. The haMPCs were cultured in vitro, and phenotypes and differentiation characteristics of cells were evaluated. OA was induced surgically by anterior cruciate ligament transection (ACLT) and medical meniscectomy of knee joints. At six weeks following surgery, hyaluronic acid (HA) or haMPCs was injected into the knee joints, the contralateral knee served as normal control. All animals were sacrificed at the 16th week post-surgery. Assessments were carried out by macroscopic examination, hematoxylin/eosin (HE) and Safranin-O/Fast green stainings and immunohistochemistry. The data showed that haMPC treatment promoted cartilage repair. Signals of human mitochondrial can be directly detected in haMPC treated cartilage. The haMPCs expressed human leukocyte antigen I (HLA-I) but not HLA-II-DR in vivo. These results suggest that intra-articular injection of haMPCs promotes regeneration of articular cartilage in rabbit OA model, and support the notion that MPCs are transplantable between HLA-incompatible individuals.

The effects of berberine on hyperhomocysteinemia and hyperlipidemia in rats fed with a long-term high-fat diet.

BACKGROUND: The study was undertaken to examine the effects of berberine (BBR) on serum homocysteine, lipids and the aortic lesion in Sprague-Dawley (SD) rats fed with a long-term high-fat diet (HFD). METHODS: Healthy male SD rats weighing 190-210 g received randomly standard diet or a high-fat diet for 24 weeks. After 8 weeks of feeding, rats fed with HFD were randomized to receive berberine (200 mg · kg-1· day-1) or vehicle by gavage for 16 weeks. After overnight fasting, all rats were sacrificed and total blood samples were also collected for determinant of fasting serum homocysteine (Hcy), total cholesterol (TC) and low density lipoprotein cholesterol (LDL-c) levels. The aorta was stained with hematoxylin and eosin (HE) and Sudan Ш to evaluate aortic lesion. The livers were dissected out and snap-frozen in liquid nitrogen for hepatic TC content and molecular analysis. 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR), Lipoprotein receptors and apolipoproteins gene expression in the liver were determined by real-time PCR. RESULTS: Intragastrical administration with berberine for 16 weeks lowered serum Hcy in rats fed with a high-fat diet. In parallel, it also decreased body weight and improved serum TC and LDL-c. Berberine also tended to decrease hepatic cholesterol. Consistently, berberine also upregulated LDL receptor (LDLR) mRNA level and suppressed HMGR gene expression. Meanwhile, upon berberine-treated rats, there was a significant increase in apolipoprotein E (apoE) mRNA, but no change in apoAI and scavenger receptor (SR) mRNA in the liver. Further, no atherosclerotic lesions were developed in berberine-treated rats for 16 weeks. CONCLUSION: Berberine can counteract HFD-elicited hyperhomocysteinemia and hyperlipidemia partially via upregulating LDLR and apoE mRNA levels and suppressing HMGR gene expression.

CD25 is a novel marker of hepatic bile canaliculus.

OBJECTIVE: Although many antigens have been investigated, the method for the bile canaliculus staining using optical microscopy needs to be improved. The aim of the present study was to assess the expression pattern of a candidate marker, CD25, in normal and diseased liver tissue. METHODS: Immunohistochemistry, immunofluorescence, and immune electron microscopy assays were performed with 41 liver sections and 2 different anti-CD25 monoclonal antibodies. A polyclonal antibody against carcinoembryonic antigen (CEA) was also used to stain bile canaliculus as a control. CD25 expression levels in normal and diseased liver tissue were also determined. RESULTS: CD25 was predominantly localized at the bile canaliculus of adult and infantile liver, evidenced by both immunohistochemistry and immunofluorescence assays. The electron microscopy assay showed that there were obvious amorphous electron-dense deposits at the bile canaliculus. In contrast, the CEA-positive area included bile canaliculus as well as basolateral aspects of hepatocytes. CD25 expression levels did not differ significantly among different disease states. CONCLUSION: This study provides the first evidence that CD25 is a novel marker of bile canaliculus. Characteristics of CD25 expression may shed light on immunohistochemistry and immunofluorescence analysis of bile canaliculus in both basic and clinical hepatic investigations.

Improvement of tissue preparation for laser capture microdissection: application for cell type-specific miRNA expression profiling in colorectal tumors.

BACKGROUND: Laser capture microdissection (LCM) has successfully isolated pure cell populations from tissue sections and the combination of LCM with standard genomic and proteomic methods has revolutionized molecular analysis of complex tissue. However, the quantity and quality of material recovered after LCM is often still limited for analysis by using whole genomic and proteomic approaches. To procure high quality and quantity of RNA after LCM, we optimized the procedures on tissue preparations and applied the approach for cell type-specific miRNA expression profiling in colorectal tumors. RESULTS: We found that the ethanol fixation of tissue sections for 2 hours had the maximum improvement of RNA quality (1.8 fold, p = 0.0014) and quantity (1.5 fold, p = 0.066). Overall, the quality (RNA integrity number, RIN) for the microdissected colorectal tissues was 5.2 +/- 1.5 (average +/- SD) for normal (n = 43), 5.7 +/- 1.1 for adenomas (n = 14) and 7.2 +/- 1.2 for carcinomas (n = 44). We then compared miRNA expression profiles of 18 colorectal tissues (6 normal, 6 adenomas and 6 carcinomas) between LCM selected epithelial cells versus stromal cells using Agilent miRNA microarrays. We identified 51 differentially expressed miRNAs (p <= 0.001) between these two cell types. We found that the miRNAs in the epithelial cells could differentiate adenomas from normal and carcinomas. However, the miRNAs in the stromal and mixed cells could not separate adenomas from normal tissues. Finally, we applied quantitative RT-PCR to cross-verify the expression patterns of 7 different miRNAs using 8 LCM-selected epithelial cells and found the excellent correlation of the fold changes between the two platforms (R = 0.996). CONCLUSIONS: Our study demonstrates the feasibility and potential power of discovering cell type-specific miRNA biomarkers in complex tissue using combination of LCM with genome-wide miRNA analysis.

Wnt signaling stabilizes the DIXDC1 protein through decreased ubiquitin-dependent degradation.

Wnt signaling plays key roles in development, cell growth, differentiation, polarity formation, neural development, and carcinogenesis. DIX Domain Containing 1 (DIXDC1), a novel component of the Wnt pathway, was recently cloned. DIXDC1 is the human homolog of Ccd1, a positive regulator of the Wnt signaling pathway during zebrafish neural patterning. Little has been known about DIXDC1 gene expression regulation. In the present study, we showed that the DIXDC1 protein was induced upon Wnt-3a stimulation, whereas the DIXDC1 mRNA level was not significantly increased after Wnt-3a treatment. Positive DIXDC1 staining was detected in colon cancer cells and was colocalized with beta-catenin staining. However, the DIXDC1 mRNA expression decreased in human colon cancer cells compared to the matched normal colon epithelial cells. Our further investigation showed that the DIXDC1 protein was degraded through the proteasome pathway, and the activation of canonical Wnt signaling decreased the ubiquitin-dependent degradation of both the ectopic and endogenous DIXDC1 protein. In order to explore the possible mechanism of the ubiquitination of DIXDC1, we found that the phosphorylation of DIXDC1 was inhibited by Wnt-3a. Collectively, these results indicate that canonical Wnt/beta-catenin pathway activation might upregulate DIXDC1 through a post-translational mechanism by inhibiting the ubiquitin-mediated degradation of the DIXDC1 protein.

PIK3CA mutations mostly begin to develop in ductal carcinoma of the breast.

Somatic mutations of PIK3CA are found in 20% to 40% of invasive breast cancers. To investigate the frequency of PIK3CA mutations in the intraductal proliferative lesions of the breast, which are precursor lesions for invasive carcinoma, we analyzed 125 intraductal proliferative lesions and 108 invasive breast cancer tissues for PIK3CA mutations in this study. Target cells were precisely isolated using a laser capture microdissection (LCM) system. Genomic DNA was extracted with QIAmp DNA Micro Kit. PCR amplification was done for exons 9 and 20 of PIK3CA, where 90% of mutations clustered, and the products were directly sequenced. Forty-six missense mutations were identified in total, of which, 14 and 32 mutations clustered in exon 9 and exon 20, respectively. The most common mutations were E542K (6 cases) and E545K (8 cases) in exon 9, and H1047R (29 cases) in exon 20. A novel mutation, G3292T, was also found. Mutations were found less frequently in the ductal intraepithelial neoplasia 1B (DIN1B) and lower grade ductal proliferative lesions (3 of 68; 4.41%) than in ductal carcinoma in situ (14 of 57; 24.56%, P=0.001, Chi-square test) or invasive carcinoma (29 of 108; 26.85%, P=0.000, Chi-square test). However, there was no significant difference in the frequency of PIK3CA mutations between carcinoma in situ and invasive carcinoma (P=0.750, Chi-square test). PIK3CA mutations mostly began to develop at the stage from the DIN1B to the carcinoma in situ (DCIS), which is a late event of breast oncogenesis. PIK3CA-mutated tumors were more frequently found in ER-a positive, PR positive, and PTEN positive tumors (P=0.012, P=0.004 and P=0.004, respectively, Chi-square test). The frequency of PIK3CA gene mutation in ER+/PR+ (32/98, 32.65%) tumors was not significantly different from that in ER+/PR- (9/39, 23.08%), tested by the Chi-square test (P=0.269). There was no significant association between PIK3CA mutations and HER2 expression status (P=0.294, Chi-square test).

DIXDC1 targets p21 and cyclin D1 via PI3K pathway activation to promote colon cancer cell proliferation.

DIXDC1 is the human homolog of Ccd1, a recently identified DIX domain containing protein in zebrafish. It is a positive regulator in the Wnt signaling pathway functioning downstream of Wnt and upstream of Axin. Since Wnt pathway activation is correlated with human colon cancer formation and progression, the biological role of DIXDC1 in human colon cancer was examined. In the current study, up-regulation of DIXDC1 protein was detected in human colorectal adenocarcinoma tissues and was found to be correlated well with high cell proliferation index. Ectopic over-expression of DIXDC1 resulted in increased cell proliferation in vitro and accelerated tumorigenesis on nude mice in vivo. We also showed that DIXDC1 promoted G0/G1 to S phase transition concomitantly with up-regulation of cyclin D1 and down-regulation of p21 protein. DIXDC1 over-expression cells showed activation of the PI3K/AKT pathway. Both siRNA knockdown of DIXDC1 and blocking the PI3K pathway using a specific inhibitor caused G1/S phase arrest, as well as down-regulation of cyclin D1 and up-regulation of p21 in DIXDC1 over-expression colon cancer cells. Collectively, this study demonstrates that over-expression of DIXDC1 might target p21 and cyclin D1 to promote colon cancer cell proliferation and tumorigenesis at least partially through activation of the PI3K/Akt pathway.

[Clonality and Ki-67 protein expression in gastric carcinoma and precancerous lesions].

OBJECTIVE: To study the clonality of gastric carcinoma and precancerous lesions and its relationship with Ki-67 protein expression. METHODS: Formalin-fixed paraffin embedded tissues were collected from 174 cases of gastric endoscopic biopsies and surgical removed specimens. The lesional tissues were isolated by Laser Capture Microdissection. Methylation sensitive restriction enzyme (HpaII) digestion and polymerase chain reaction (PCR) were used to detect the clonality at the polymorphic human androgen receptor gene locus on the X chromosome. PCR products were analyzed by capillary electrophoresis using applied Biosystems 3730 DNA Analyzer. In addition, a two-step immunohistochemical staining EnVision method was used to detect the expression of Ki-67 protein. RESULTS: The frequency of detection of monoclonality and expression rate of Ki-67 were found increased in a stepwise fashion from gastrointestinal metaplasia, low grade intraepithelial neoplasia, high grade intraepithelial neoplasia to intestinal carcinoma (15.63%, 5/32; 22.22%, 10/45; 69.44%, 25/36 and 100.0%, 20/20; respectively). The presence of clonal proliferation was correlated with Ki-67 expression in low grade intraepithelial neoplasia (P < 0.01). CONCLUSIONS: The presence of clonal proliferation and increased Ki-67 are increasingly detected in the lesions along the multi-step gastric carcinogenesis model. Clonal status is associated with the expression rate of Ki-67 to a certain extent, suggesting a combined application of both markers may be useful in assessing early stages of gastric carcinoma.

[Expression and significance of hTERT mRNA in breast carcinoma and its relation to p53].

OBJECTIVE: This study was designed to investigate the significance of hTERT mRNA in breast carcinogenesis and to explore the diagnostic efficacy, and to study the effect of tumor suppressor gene p53 on the expression of hTERT mRNA. METHODS: The expression of hTERT mRNA was examined by in situ hybridization in 12 cases of normal breast tissue nearby cancer, 7 of simple ductal hyperplasia, 20 of atypical hyperplasia, 18 of ductal carcinoma in situ and 25 with invasive ductal carcinoma. The expression of p53 protein were examined by immunohistochemistry in 43 carcinomas. RESULTS: hTERT was not detected in normal breast tissue nearby cancer and simple ductal hyperplasia. The positive rate of hTERT mRNA in atypical hyperplasia, ductal carcinoma in situ and invasive ductal carcinoma were 25.0%, 83.3% and 88.0%, respectively. The prevalence and intensity of hTERT mRNA expression were much greater in carcinoma than those in simple or atypical hyperplasia and normal breast tissue nearby cancer (P < 0.05). The expression of hTERT was not correlated with tumor size and lymph node metastasis (P > 0.05). The positive correlation between hTERT mRNA and p53 was found in breast carcinoma (r = 0.5540, P < 0.01). CONCLUSION: hTERT mRNA expression is closely related to the malignant transformation of breast tissue. Semi-quantitative detection of hTERT mRNA expression in situ is helpful in differentiated diagnosis of carcinoma in situ and atypical hyperplasia. Inactivation of p53 may play a role in the transcriptive activation of hTERT gene in breast carcinoma.