IGFBP-rP1, a potential molecule associated with colon cancer differentiation

<p>Abstract</p> <p>Background</p> <p>In our previous studies, we have demonstrated that insulin-like growth factor binding protein-related protein1 (IGFBP-rP1) played its potential tumor suppressor role in colon cancer cells through apoptosis and senescence induction. In this study, we will further uncover the role of IGFBP-rP1 in colon cancer differentiation and a possible mechanism by revealing responsible genes.</p> <p>Results</p> <p>In normal colon epithelium, immunohistochemistry staining detected a gradient IGFBP-rP1 expression along the axis of the crypt. IGFBP-rP1 strongly expressed in the differentiated cells at the surface of the colon epithelium, while weakly expressed at the crypt base. In colon cancer tissues, the expression of IGFBP-rP1 correlated positively with the differentiation status. IGFBP-rP1 strongly expressed in low grade colorectal carcinoma and weakly expressed in high grade colorectal carcinoma. In vitro, transfection of PcDNA3.1(IGFBP-rP1) into RKO, SW620 and CW2 cells induced a more pronounced anterior-posterior polarity morphology, accompanied by upregulation with alkaline phosphatase (AKP) activity. Upregulation of carcino-embryonic antigen (CEA) was also observed in SW620 and CW2 transfectants. The addition of IGFBP-rP1 protein into the medium could mimic most but not all effects of IGFBP-rP1 cDNA transfection. Seventy-eight reproducibly differentially expressed genes were detected in PcDNA3.1(IGFBP-rP1)-RKO transfectants, using Affymetrix 133 plus 2.0 expression chip platform. Directed Acyclic Graph (DAG) of the enriched GO categories demonstrated that differential expression of the enzyme regulator activity genes together with cytoskeleton and actin binding genes were significant. IGFBP-rP1 could upreguate Transgelin (TAGLN), downregulate SRY (sex determining region Y)-box 9(campomelic dysplasia, autosomal sex-reversal) (SOX9), insulin receptor substrate 1(IRS1), cyclin-dependent kinase inhibitor 2B (p15, inhibits CDK4) (CDKN2B), amphiregulin(schwannoma-derived growth factor) (AREG) and immediate early response 5-like(IER5L) in RKO, SW620 and CW2 colon cancer cells, verified by Real time Reverse Transcription Polymerase Chain Reaction (rtRT-PCR). During sodium butyrate-induced Caco2 cell differentiation, IGFBP-rP1 was upregulated and the expression showed significant correlation with the AKP activity. The downregulation of IRS1 and SOX9 were also induced by sodium butyrate.</p> <p>Conclusion</p> <p>IGFBP-rP1 was a potential key molecule associated with colon cancer differentiation. Downregulation of IRS1 and SOX9 may the possible key downstream genes involved in the process.</p

Attempts to minimize nitrogen oxide emission from diesel engine by using antioxidant-treated diesel-biodiesel blend.

The study represents a comprehensive analysis of engine exhaust emission variation from a compression ignition (CI) diesel engine fueled with diesel-biodiesel blends. Biodiesel used in this investigation was produced through transesterification procedure from Moringa oleifera oil. A single cylinder, four-stroke, water-cooled, naturally aspirated diesel engine was used for this purpose. The pollutants from the exhaust of the engine that are monitored in this study are nitrogen oxide (NO), carbon monoxide (CO), hydrocarbon (HC), and smoke opacity. Engine combustion and performance parameters are also measured together with exhaust emission data. Some researchers have reported that the reason for higher NO emission of biodiesel is higher prompt NO formation. The use of antioxidant-treated biodiesel in a diesel engine is a promising approach because antioxidants reduce the formation of free radicals, which are responsible for the formation of prompt NO during combustion. Two different antioxidant additives namely 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (MBEBP) were individually dissolved at a concentration of 1% by volume in MB30 (30% moringa biodiesel with 70% diesel) fuel blend to investigate and compare NO as well as other emissions. The result shows that both antioxidants reduced NO emission significantly; however, HC, CO, and smoke were found slightly higher compared to pure biodiesel blends, but not more than the baseline fuel diesel. The result also shows that both antioxidants were quite effective in reducing peak heat release rate (HRR) and brake-specific fuel consumption (BSFC) as well as improving brake thermal efficiency (BTE) and oxidation stability. Based on this study, antioxidant-treated M. oleifera biodiesel blend (MB30) can be used as a very promising alternative source of fuel in diesel engine without any modifications

Higher alcohol-biodiesel-diesel blends: An approach for improving the performance, emission, and combustion of a light-duty diesel engine

Pentanol is a long-chain alcohol with five carbons in its molecular structure and is produced from renewable feedstock, which may help to improve the challenging problems of energy security and environmental issues. In this investigation, the performance, emission, and combustion characteristics of a single-cylinder, four-stroke, water-cooled, direct-injection diesel engine were evaluated by using 10%, 15%, and 20% pentanol and Calophyllum inophyllum (CI) biodiesel blends in diesel under different speed conditions. The fuel properties of the blended fuels were measured and compared. Combustion attributes, such as cylinder pressure and heat-release rate, were also analyzed. Results indicated that increasing the proportion of pentanol in biodiesel blends improved the fuel properties compared with 20% blend of CI biodiesel (CI 20). The modified blends of pentanol showed reduced brake-specific fuel consumption with higher brake thermal efficiency and brake power than CI 20. Although the modified test blends showed a slightly higher nitric oxide emission, the carbon monoxide emission and unburned hydrocarbon emission for 15% and 20% blends of pentanol showed even better reduction than CI 20. Smoke emission was also reduced significantly. The carbon dioxide emission of the test blends were reduced at the maximum speed condition compared to CI 20. In terms of combustion, the modified test fuels exhibited a significant improvement, thus indicating better performance and emission. This study concluded that the 15% and 20% blends of biodiesel, diesel, and pentanol can optimize engine performance and emission without any engine modification

Performance and emission characteristics of double split injection biodiesel engine with intake air throttling

Most diesel engines typically operate with high excess air in part load. Implementing air intake restriction with exhaust gas recirculation (EGR) could be a viable option for mitigating NOx emission and soot, particularly when utilizing biodiesel, attributing to biodiesel's inherent oxygen content. This study examines the effect of intake air throttle and EGR coupled with split injection strategies on a turbocharged 4-cylinder engine fuelled with B60-POME fuel. A parametric test was conducted to examine the impact of fuel injection pressure, intake air throttling and EGR, followed by Response Surface Methodology (RSM) optimisation. When EGR is implemented with a 45% intake throttle opening, a relatively low EGR rate of 5% is achieved. A study utilising RSM was conducted to optimise the control of air supply and split injection parameters, involved with a total of 6 control variables. The optimum parameter appears at a dwell angle of 12 °CA, SOI timing of −4°ATDC, 40% intake throttle opening, EGR of 6.75%, fuel injection pressure of 800 bar and split injection ratio of 50%. These settings yield prediction emission results that are closely similar to those obtained from the actual confirmation test