Difference between revisions of "Team:JSNU-China/Description"

 
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<a href="https://2016.igem.org/Team:JSNU-China/Description"><img src="https://static.igem.org/mediawiki/2016/b/b2/Jsnuchina_project.png" width="80%"></a>
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<a href="https://2016.igem.org/Team:JSNU-China/Description"><img src="https://static.igem.org/mediawiki/2016/9/9a/Jsnuchina_projectchange.png" width="80%"></a>
 
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<a href="https://2016.igem.org/Team:JSNU-China/Description#background"><p class="p2"><center>Background</center></p></a>
 
<a href="https://2016.igem.org/Team:JSNU-China/Description#background"><p class="p2"><center>Background</center></p></a>
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                        <a href="https://www.youtube.com/watch?v=bmXjtAJiko4" target="_blank"><img src="https://static.igem.org/mediawiki/2016/4/45/Jsnuchina_jiaojuan.png" style="width:65%;height: 200px;position: absolute;top: 110px;right:2%;z-index: 3;"></a>
 
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<p>Although it is one of the most researched and funded fields in medicine, cancer is still a major cause of morbidity and mortality all over the world, with 14 million new cases and over 8 million deaths per year. It is also the second cause of death and is responsible for quarter of the death cases among developed countries.
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<p>Although it is one of the most researched and funded fields in medicine, cancer is still a major cause of morbidity and mortality all over the world, with 14 million new cases and over 8 million deaths per year. It is also the second cause of death and is responsible for quarter of the death cases among developing countries.
 
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<p>
People have tried many ways to keep health or prevent cancer, such as eating some healthy diet, keeping active, avoiding certain infections and so on. Anthocyanin as a natural colorants in food with health-promoting properties, which could help protect our heart health and boost our cancer defense, and during the process of preventing and curing cancer, doctors always encourage patients to use anthocyanin-like foods and drugs. However, anthocyanin cannot kill cancer cells and prevent more from growing in our bodies effectively.
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People have tried many ways to keep health or prevent cancer, such as eating some healthy diet, keeping active, avoiding certain infections and so on. Anthocyanin works as a natural colorant in food with health-promoting properties, which could protect our hearts and boost our cancer defense, and during the process of preventing and curing cancer, doctors always encourage patients to use anthocyanin-like foods and drugs. However, anthocyanin cannot kill cancer cells and prevent more from growing in our bodies effectively.
  
 
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<h4>1.We constructed GFP-plasmid and transfected it into SUM52 cells. After 72h, we could detect green fluorescent protein in almost 90% SUM52 cells.</h4>
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<h4>1.We constructed GFP-plasmid and transfected it into SUM52 cells. After 72h, we could detect green fluorescent protein in almost 90% of SUM52 cells.</h4>
 
<br>
 
<br>
<p>(a)Q-PCR</p>
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<center><img class="img1" src="https://static.igem.org/mediawiki/2016/f/f1/Jsnuchina_Fig1-1.png" width="80%"></center>
<p>(b)Western blot</p>
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<p>Fig1.Transfect GFP-plasmid into SUM52 with liposome</p>
<center><img class="img1" src="https://static.igem.org/mediawiki/2016/a/a1/Jsnuchina_exp1.jpg" width="80%"></center>
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<h4>2.We set up one SUM52-GFP stable cell line and treated it with different concentrations of anthocyanin. The results of fluorescence microscopy and cell counting kit-8(CCK-8) suggested anthocyanin can kill SUM52 cells.</h4>
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<center><img src="https://static.igem.org/mediawiki/2016/8/8b/Jsnuchina_Fig2.png" width="80%"></center>
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                                        <p>Fig2.SUM52-GFP treated with different concentrations of anthocyanin(4x)</p>
 
<br>
 
<br>
<center><img class="img1" src="https://static.igem.org/mediawiki/2016/7/70/Jsnuchina_exp2.jpg" width="80%"></center>
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                                        <center><img src="https://static.igem.org/mediawiki/2016/8/85/Jsnuchina_Fig3.png" width="80%"></center>
<p>Through these two methods, we examined the KLF4 expression of two aspects, about RNA and protein levels. KLF4 is indeed a lower expression in gastric cancer cells.</p>
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                                        <p>Fig3.CCK-8 kit to test the cell viability of SUM52-GFP cells</p>
<h4>2)At the same time we treated with different concentrations of anthocyanin GES1 and HGC27 cells, as a control. Illustrates the anthocyanins on gastric cancer cell is certain killing effect, and is not too much of a role for normal cells.</h4>
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<center><img src="https://static.igem.org/mediawiki/2016/4/41/Jsnuchina_exp3.jpg" width="70%"></center>
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<h4>3.We treated normal human gastric epithelial cell line- GES1 and gastric cancer cell line-HGC27 with different concentrations of anthocyanin and tested the cells' viability with CCK-8 kit.The result of CCK-8 showed that anthocyanin had the effect of killing HGC27 cell and had a little effect on GES1 cell lines. We also found normal cells can't endure high concentration of anthocyanin for a long time.</h4>
<h4>3)Before constructing plasmids , we transfect  SUM52 with GFP plasmid to check transfection efficiency. The results as shown:</h4>
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<center><img src="https://static.igem.org/mediawiki/2016/3/33/Jsnuchina_exp3_1.png" width="100%"></center>
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<center><img src="https://static.igem.org/mediawiki/2016/2/23/Jsnuchina_Fig4.png" width="100%"></center>
 
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<p>Fig4.CCK-8 kit to test the cell viability of cell lines</p>  
<p>The experimental results show that our transfection is efficient.</p>
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                                        <p>(a)GES1 cell (b)HGC27</p>
<p>Then, we use the concentration of 0 ug/ml, respectively 100 ug/ml, 200 ug/ml, 300 ug/ml anthocyanins handled transfection GFP plasmid SUM52 cells, then the cell apoptosis by fluorescence microscope observation.The results are as follows.</p>
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<h4 style="color:rgb(90,117,82) !important;">These experiments showed anthocyanin was a kind of powerful anti-cancer substance. There are many opportunities for humanity to intake anthocyanin for a long time in the course of their entire life. But no research has data to prove the cancer incidence is different between inadequate or excessive intake anthocyanin. Why humanity can't prevent and destroy cancers with it? Maybe, we need push it. We try to find a gene which is special for cancer cell. Is there a hidden traitor in cancer cells? KLF4 is a transcription factor acting as both activator and repressor.</h4>
<center><img src="https://static.igem.org/mediawiki/2016/6/61/Jsnuchina_exp4.jpg" width="80%"></center>
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                                        <h4>4.We tested KLF4’s expression in various cancer cells by q-PCR and western blot. The results showed that KLF4’s expression is different in a bunch of cancer cells cultured in our lab, mostly downregulation compared with normal human gastric epithelial cell line- GES1.</h4>
<p>If the expression of klf4 is higher, will the cancer cells die faster after dealing with anthocyanins?</p>
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                                        <center><img src="https://static.igem.org/mediawiki/2016/5/57/Jsnuchina_Fig5.png" width="80%"></center>
</div>
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                                        <p>Fig5. KLF4’s expression in different cancer cell lines</p>
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                                        <p>(a)q-PCR (b)Western Blot</p>
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                                        <h4>5.We constructed KLF4 over-expression and 5 mutant plasmids.</h4>
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<p>1)Design 6 templates with specific restriction sites for cloning</p>
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                <center><img src="https://static.igem.org/mediawiki/2016/6/6b/Jsnuchina_Fig6.png.png" width="70%"></center>
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                                        <p>  Fig6. The schematic diagram of five mutants  </p>
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<div id="experright">
 
<div id="experright">
<h3>Formal experiment</h3>
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<p>2)</p>
<p>We decided to construct KLF4 over-expressed plasmid based on the results of preliminary experiments.</p>
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                                        <center><img src="https://static.igem.org/mediawiki/2016/9/94/Jsnuchina_Fig7.png" width="90%"></center>
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<p>3)Cloning of "master" into vector</p>
<center><img src="https://static.igem.org/mediawiki/2016/b/bb/Jsnuchina_exp5.jpg" width="80%"></center>
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                                        <center><img src="https://static.igem.org/mediawiki/2016/2/29/Jsnuchina_Fig7-1.png" width="55%"></center>
<p>Through PCR, restriction enzyme digestion, connections, repeated tests have been completed the construction of the plasmid. Then, we put KLF4 over-expression plasmid into 293 cells , and spent a long time to get stably expressing screened cell lines. Then we do western blot again detection of protein inside cells, protein expression plasmid construction is proof of our success.</p>
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                                        <p>       Fig7.BBa_K2000006</p>
<br>
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                                        <h4>After 3 weeks, we selected one KLF4 over-expression cell line from HEK293T cell with G418. WB’s results make sure KLF4 over-expressed in our HEK293-KLF4 cell.</h4>
<p>We successfully constructed KLF4 over-expression n of cell.</p>
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                                        <center><img src="https://static.igem.org/mediawiki/2016/3/32/Jsnuchina_Fig9.png" width="40%"></center>                                     
<br>
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                                        <p>Fig8.KLF4 over expressed in HEK293T-KLF4 cell.</p>
<img src="https://static.igem.org/mediawiki/2016/d/d3/Jsnuchina_exp4_1.png" width="50%" style="border-radius:8px;float:left;margin-left:8%;">
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                                        <h4>6.Then, we treated HEK293T-KLF4 and HEK293T cells with different concentrations of anthocyanin. After 3 days, HEK293T-KLF4 cells all dead while HEK293T cells dead after 6 days with anthocyanin treatment. The results of CCK-8 kit and light microscopy are consistent which showed upregulation of KLF4 will make HEK293T cell more sensitive to anthocyanin.</h4>
<p>According to the results of preliminary experiments, the cancer cells have a certain anthocyanins cytotoxicity .Then we dealt with the cells of anthocyanins.</p>
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                                        <center><img src="https://static.igem.org/mediawiki/2016/b/b9/Jsnuchina_Fig10..png" width="110%"></center>
<br>
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                                        <p>Fig9.HEK293T cells treated with different concentrations of anthocyanin</p>
 
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                                        <p>(a)Light microscope showed HEK293T cells dead after 6 days with anthocyanin treatment.</p>
<center><img src="https://static.igem.org/mediawiki/2016/6/6c/Jsnuchina_exp6.png" width="80%" style="margin-top: 10px;">
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                                        <p>(b)CCK-8 also detected HEK293T cells dead with anthocyanin treatment.</p>
<p>and then every day CCK8 reagent for detecting cell viability, We also treated with the same concentration of anthocyanins normal 293 cells were used as controls</p>
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                                        <center><img src="https://static.igem.org/mediawiki/2016/0/03/Jsnuchina_Fig11.png" width="110%"></center>
<p>So We have two ways to check the viability of cells - electron micrographs of the cells and the data detection CCK8, we have two sets of data.</p>
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                                        <p>Fig10.HEK293T-KLF4 cells treated with different concentrations of anthocyanin</p>
<img src="https://static.igem.org/mediawiki/2016/4/44/Jsnuchina_exp7.png" width="50%" style="margin-top: 10px;">
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                                        <p>(a)Light microscope showed HEK293T-KLF4 cells dead after 3 days with anthocyanin treatment.</p>
<img src="https://static.igem.org/mediawiki/2016/9/91/Jsnuchina_exp8.png" width="40%" style="margin-top: 10px;"></center>
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                                        <p>(b)CCK-8 also detected HEK293T cells dead with anthocyanin treatment.</p>
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                                        <h4 style="color:rgb(90,117,82) !important;">Our results are so funny, just as the Chinese old saying goes, A mix of Jacks and Jills makes a tough job a breeze. KLF4 maybe is Ms. anthocyanin's Mr. right. Upregulation of KLF4's expression maybe help increase cancer cells' sensitivity to anthocyanin. Another truth is , cancer cells will tolerate it after  a long time of taking in anthocyanin.  KLF4 downregulated in some cancer cells to help its cancer stem cell  to escape from immune system, including lost sensibility to anti-cancer drug. That's why we can't use anthocyanin in clinical cancer therapy. Maybe, our work throw a little light in this dilemma, we can find a plant inside the cancer cells to cooperate with anthocyanin and destroy cancer cell.</h4>
</center>
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                                        <h4 style="color:rgb(90,117,82) !important;">In the future, we'll do more jobs about the molecular mechanism of anthocyanin and KLF4. We also finished constructing 5 mutants to explore the relation of KLF4 and anthocyanin.</h4>
<center><img src="https://static.igem.org/mediawiki/2016/f/f2/Jsnuchina_exp9.png" width="80%"></center>
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                                        <p>References:</p>
<br>
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                                        <p>[1] Zhang ZF, Lu J, Zheng YL, et al. Purple sweet potato color attenuates hepatic insulin resistance via blocking oxidative stress and endoplasmic reticulum stress in high-fat-diet-treated mice.J Nutr Biochem. 2013,Jun 24(6):1008-18.</p>
<p>Two sets of data show, KLF4 anthocyanin treated with high-expressing cells on the first day of the death, and the third day all died. While the normal 293 anthocyanins cells treated in four days there has been death, by comparison, KLF4 over-expression greatly increased the sensitivity of cancer cells anthocyanins.</p>
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                                        <p>[2] Lu J, Wu DM, Zheng YL et al. Purple Sweet Potato Color Alleviates D‐galactose‐induced Brain Aging in Old Mice by Promoting Survival of Neurons via PI3K Pathway and Inhibiting Cytochrome C‐mediated Apoptosis . Brain Pathol. 2010 May;20(3):598-612.</p>
<br>
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                                        <p>[3] Capra hircus Kruppel-like factor 4 (KLF4) mRNA, complete cds.https://www.ncbi.nlm.nih.gov/nucleotide/1021691550?report=genbank&log$=nuclalign&blast_rank=10&RID=Z74WM35U015</p>
<p>Thus, we conclude that KLF4 over-expression greatly increased the sensitivity of cancer cells anthocyanins. Then, we have great interest about how KLF4 regulatory anthocyanins and cancer cells generated, we decided to study the issue of mechanisms.</p>
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<img src="https://static.igem.org/mediawiki/2016/a/a8/Jsnuchina_future1.jpg" width="70%" />
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<p>
<p>According to KLF4 structure, We construct to build another four mutant.</p>
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                                                      Compared with traditional chemotherapy, combining eating foods rich in anthocyanin with gene therapy has many advantages, such as no harm and lower cost in treatment. Since everybody's genes are different, we can treat patients one-to-one in gene therapy. In this way, we will get a more efficient result and we don't need to take medicine any more. We can take in anthocyanin from grapes, cherries, strawberries and some food that we can purchase easily.</p>
<img class="imgchange" src="https://static.igem.org/mediawiki/2016/8/89/Jsnuchina_future2.jpg" width="52%" style="margin-right:1%" />
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<img class="imgchange" src="https://static.igem.org/mediawiki/2016/c/c0/Jsnuchina_future3.jpg" width="46%" />
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<p>However, due to time constraints, we have not had time to make this part of the work, which will be our next will try to complete the work</p>
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<div id="pro">
<h3>The experimental operation we mainly used</h3>
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<h4>1.Molecular Cloning</h4>
<h4>1.EnoGeneCell Counting Kit-8</h4>
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<p>Molecular cloning is a set of experimental methods in molecular biology that are used to assemble recombinant DNA molecules and to direct their replication within host organisms.</p>
<p>Detection principle</p>
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<p>In the molecular cloning experiment, the KLF4 to be cloned is combined with vector DNA to generate recombinant DNA molecules. The recombinant DNA is then introduced into E. coli bacteria. This will generate a population of organisms in which recombinant DNA molecules are replicated along with the host DNA. This is single cell then can be expanded exponentially to generate a large amount of bacteria, each of which contain copies of the original recombinant molecule.</p>
<p>◆Cell Counting Kit Acronym CCK8 kit is based WST-8 (chemical name: 2- (2-methoxy-4-nitro-phenyl) -3- (4-nitro-phenyl) -5- (2 , 4-sulfophenyl) -2H- tetrazolium monosodium salt) is widely used in cell proliferation and cytotoxicity of fast, high-sensitivity detection kit.</p>
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<h4>2.Cell culture</h4>
<p>◆WST-8 belonging to MTT upgrade products, works as follows: In the case of electronic coupling agent is present and can be restored Dehydrogenase mitochondria produce highly water-soluble orange formazan product (formazan). Color depth and proliferation of cells is directly proportional to cell toxicity. OD value was measured using a microplate reader at a wavelength in the 450mM indirectly reflect the number of viable cells.</p>
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<p>Cell culture is the complex process by which cells are grown under controlled conditions, outside their natural environment, an essential aspect of cloning technology. We can get a lot of cells or metabolites through cell culture.</p>
<p>◆CCK8 method is widely used, such as drug screening, cell proliferation assay, cytotoxicity assays, tumor susceptibility testing and detection of biological activity and other factors.</p>
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<p>Cell Viability Assay</p>
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<p>1, the cell suspension seeded in 96-well plates (100μL / well). The plates were pre-incubated in an incubator (37 ℃, 5% CO2).</p>
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<p>2, was added to each well 10 μL CCK8 solution (be careful not to bubble Kong Zhongsheng, they can affect the reading OD values).</p>
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<p>3, the plates were incubated in the incubator for 1-4 hours.</p>
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<p>4, then determined by comparing the absorbance at 450nm.</p>
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<p>5, if the OD value temporarily, can be added to 10 μL 0.1M HCL solution or 1% w / v SDS solution to each well, and the cover plates stored in the dark at room temperature. Within 24 hours measured absorbance change does not occur.</p>
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<p>Cell viability * (%) = [A (dosing) -A (Blank)] / [A (0 dosing) -A (Blank)] × 100</p>
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<h4>2.Molecular Cloning</h4>
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<center><img src="https://static.igem.org/mediawiki/2016/0/08/Jsnuchina_pro.png" class="proimg" width="80%"></center>
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<h4>3.Western blot</h4>
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<p>Extract proteins</p>
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<p>1.1000r/min centrifuge for 5 minutes to remove PBS.</p>
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<p>2.Add lysis buffer and shake it.</p>
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<p>3.12000r/min freezing centrifuge for 15minutes</p>
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<p>4.Add loading buffer and boil for 10 minutes</p>
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<p>5.Put it on the ice.</p>
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<br>
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<p>SDS-PAGE</p>
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<p>1. Plates:The sealed box with silica gel placed flat on the glass, and then the concave glass and flat glass overlap, the two glass stand up to make contact with the bottom of the desktop, two glass hand clamped into the electrophoresis tank, then insert Xiecha board to moderate degree, you can glue.</p>
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<p>2. Polymer gel:Separating gel and stacking gel preparation: The following table sequentially and proportion solution, configuration of 10% separating gel and 4.8% stacking gel.</p>
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<p>3.</p>
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<center>
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<table width="60%" border="1" style="border-color:#ddd" cellpadding="5">
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<tr>
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<td></td>
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<td>Separating gel</td>
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<td>Stacking gel</td>
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</tr>
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<tr>
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<td>ddH2O</td>
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<td>4.95ml</td>
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<td>3.05ml</td>
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</tr>
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<tr>
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<td>Arc-Bis(30%)</td>
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<td>6ml</td>
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<td>0.67ml</td>
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</tr>
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<tr>
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<td>Tris-Hcl</td>
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<td>3.75ml(PH=8.8)</td>
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<td>1.25ml(PH=6.8)</td>
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</tr>
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<tr>
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<td>10%SDS</td>
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<td>150ul</td>
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<td>50ul</td>
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</tr>
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<tr>
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<td>10%APS</td>
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<td>150ul</td>
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<td>50ul</td>
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</tr>
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<tr>
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<td>TEMED</td>
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<td>15ul</td>
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<td>10ul</td>
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</tr>
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</table>
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</center>
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<p>Following the above table, mix them.After separating gel formulation, add it to the gel, be careful not to produce bubbles. Then add water carefully to make surface covered with water.Put them on room temperature about 30-40min. When absorb the water completely, prepare stacking gel according to the above table. Add stacking gel and insert the comb .Finally,carefully remove the sample.</p>
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<p>4.Loading:add sample to the sample tank</p>
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<p>5.Electrophoresis</p>
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<br>
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<p>Transfer and block</p>
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<p>1.transfer the protein to PVDF membrane.</p>
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<p>2.block the membrane with 5% milk 1h.</p>
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<p>3.add the first antibody and overnight at 4 degrees temperature.</p>
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<p>4.wash membrane 15min 3 times.</p>
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<p>5.add second antibody 1h at room temperature. </p>
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<p>6.wash membrane 15min 3 times.</p>
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<br>
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<p>Expose</p>
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<p>Expose and we can see the result clearly.</p>
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<h4>4.Cell culture</h4>
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<p>Cell culture technology refers to the number of cells after a lot of training to become a simple single cell or a little more differentiated cells, which are essential aspects of cloning technology. We can get a lot of cells or metabolites through cell culture. Because biological products are derived from the cells, it can be said cell culture technology is biotechnology core, the most basic technology. </p>
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<p>Cell recovery</p>
 
<p>Cell recovery</p>
<p>1.We put cryopreserved tubes in 37 degrees temperature water bath pot and shake it until dissolved.We can complete the thawing about one to two minutes.</p>
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<p>1. We put cryopreserved tubes in water bath pot (37℃) and shake it until cells dissolved. We can complete the thawing in 1-2 minutes.</p>
<p>2.Put cryopreservation solution and 5 ml of culture into a centrifuge tube and Pipet.</p>
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<p>2. Move cells into the centrifuge tube (5 ml).</p>
<p>3.1000r/min centrifuge for 5 minutes</p>
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<p>3. Centrifugation for 5 minutes, 1000r/min.</p>
<p>4.Add the precipitate to complete medium, pipetting, transferred to a Petri dish.</p>
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<p>4. After centrifugation, we discard the supernatant and move the precipitation to a petri dish.</p>
<br>
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                                <br>
 
<p>Cell culture</p>
 
<p>Cell culture</p>
<p>Add 55ml serum and 6ml Dual anti to the medium.</p>
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<p>1.Add 55ml serum and 6ml Penicillin-Streptomycin Solution to the medium.</p>
<br>
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<p>2.Add the medium to the petri dish.</p>
<p>Collect cell</p>
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                                <br>
<p>6.Add Trypsin and stop digestionafter cell culture medium plus curled .</p>
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                                <p>Cell collection</p>
<p>7.Absorb the culture medium to completely blow down cells.</p>
+
<p>1.Digest cells with trypsin, then stop it with cell culture medium.</p>
<p>8.Transfer the cells to a centrifuge tube and centrifuge for 5 minutes</p>
+
<p>2.Remove the medium, then the cells sedimentated.</p>
<p>9.Discard the supernatant, add wash cells with PBS.</p>
+
                                <p>3.The cells are moved to a centrifuge tube and centrifuged for 5 minutes.</p>
<p>10.1000r/min centrifuge for 5 minutes</p>
+
                                <p>4.Discard the supernatant, and wash cells with PBS.</p>
<p>11.Discard the supernatant and add frozen -80 degrees to cryopreservate.</p>
+
                                <p>5.Centrifugation for 5 minutes, 1000r/min.</p>
 +
                                <p>6.Discard the supernatant and cryopreservate the cells at -80℃.</p>
 +
                                <br>
 +
                                <h4>3.Western blot</h4>
 +
                                <p>Western blotting uses specific antibodies to identify proteins that have been separated based on size by gel electrophoresis. The immunoassay uses a membrane made of nitrocellulose or PVDF (polyvinylidene fluoride). The gel is placed next to the membrane and application of an electrical current induces the proteins to migrate from the gel to the membrane. The membrane can then be further processed with antibodies specific for klf4, and visualized by using secondary antibodies detection reagents.</p>
 +
                                <br>
 +
                                <h4>4.Cell Counting Kit-8</h4>
 +
                                <p>Cell Counting Kit-8 is based on WST-8 (chemical name: 2- (2-methoxy-4-nitro-phenyl) -3- (4-nitro-phenyl) -5- (2, 4-sulfophenyl) -2H- tetrazolium monosodium salt) which is widely used in drug screening, cell proliferation assay, cytotoxicity assay, tumor susceptibility testing and detection of biological activity and so on.</p>
 +
                                <br>
 +
                                <p>CCK-8 was produced by TransGen Biotech.</p>
 
</div>
 
</div>
 
</div>
 
</div>

Latest revision as of 17:28, 19 October 2016

project

Background

Although it is one of the most researched and funded fields in medicine, cancer is still a major cause of morbidity and mortality all over the world, with 14 million new cases and over 8 million deaths per year. It is also the second cause of death and is responsible for quarter of the death cases among developing countries.

People have tried many ways to keep health or prevent cancer, such as eating some healthy diet, keeping active, avoiding certain infections and so on. Anthocyanin works as a natural colorant in food with health-promoting properties, which could protect our hearts and boost our cancer defense, and during the process of preventing and curing cancer, doctors always encourage patients to use anthocyanin-like foods and drugs. However, anthocyanin cannot kill cancer cells and prevent more from growing in our bodies effectively.

About  anthocyanin

Anthocyanin is a type of natural flavonoid and antioxidant with powerful anti-cancer properties. Anthocyanin will be able to protect against cancer indirectly through the prevention of DNA damage. Anthocyanin can also make cancer cells not be successfully diffused, thereby protecting the healthy cells not being eroded by cancerous ones.

About  KLF4

Kruppel-like-factor 4(KLF4)is a zinc-finger transcriptional factor that regulate gene expression. KLF4’s expression level is different in gastric cancer, lung cancer, bladder cancer ,breast cancer and oral squamous cell.

Experiment

1.We constructed GFP-plasmid and transfected it into SUM52 cells. After 72h, we could detect green fluorescent protein in almost 90% of SUM52 cells.


Fig1.Transfect GFP-plasmid into SUM52 with liposome

2.We set up one SUM52-GFP stable cell line and treated it with different concentrations of anthocyanin. The results of fluorescence microscopy and cell counting kit-8(CCK-8) suggested anthocyanin can kill SUM52 cells.

Fig2.SUM52-GFP treated with different concentrations of anthocyanin(4x)


Fig3.CCK-8 kit to test the cell viability of SUM52-GFP cells


3.We treated normal human gastric epithelial cell line- GES1 and gastric cancer cell line-HGC27 with different concentrations of anthocyanin and tested the cells' viability with CCK-8 kit.The result of CCK-8 showed that anthocyanin had the effect of killing HGC27 cell and had a little effect on GES1 cell lines. We also found normal cells can't endure high concentration of anthocyanin for a long time.

Fig4.CCK-8 kit to test the cell viability of cell lines

(a)GES1 cell (b)HGC27

These experiments showed anthocyanin was a kind of powerful anti-cancer substance. There are many opportunities for humanity to intake anthocyanin for a long time in the course of their entire life. But no research has data to prove the cancer incidence is different between inadequate or excessive intake anthocyanin. Why humanity can't prevent and destroy cancers with it? Maybe, we need push it. We try to find a gene which is special for cancer cell. Is there a hidden traitor in cancer cells? KLF4 is a transcription factor acting as both activator and repressor.

4.We tested KLF4’s expression in various cancer cells by q-PCR and western blot. The results showed that KLF4’s expression is different in a bunch of cancer cells cultured in our lab, mostly downregulation compared with normal human gastric epithelial cell line- GES1.

Fig5. KLF4’s expression in different cancer cell lines

(a)q-PCR (b)Western Blot

5.We constructed KLF4 over-expression and 5 mutant plasmids.

1)Design 6 templates with specific restriction sites for cloning

Fig6. The schematic diagram of five mutants

2)

3)Cloning of "master" into vector

Fig7.BBa_K2000006

After 3 weeks, we selected one KLF4 over-expression cell line from HEK293T cell with G418. WB’s results make sure KLF4 over-expressed in our HEK293-KLF4 cell.

Fig8.KLF4 over expressed in HEK293T-KLF4 cell.

6.Then, we treated HEK293T-KLF4 and HEK293T cells with different concentrations of anthocyanin. After 3 days, HEK293T-KLF4 cells all dead while HEK293T cells dead after 6 days with anthocyanin treatment. The results of CCK-8 kit and light microscopy are consistent which showed upregulation of KLF4 will make HEK293T cell more sensitive to anthocyanin.

Fig9.HEK293T cells treated with different concentrations of anthocyanin

(a)Light microscope showed HEK293T cells dead after 6 days with anthocyanin treatment.

(b)CCK-8 also detected HEK293T cells dead with anthocyanin treatment.

Fig10.HEK293T-KLF4 cells treated with different concentrations of anthocyanin

(a)Light microscope showed HEK293T-KLF4 cells dead after 3 days with anthocyanin treatment.

(b)CCK-8 also detected HEK293T cells dead with anthocyanin treatment.

Our results are so funny, just as the Chinese old saying goes, A mix of Jacks and Jills makes a tough job a breeze. KLF4 maybe is Ms. anthocyanin's Mr. right. Upregulation of KLF4's expression maybe help increase cancer cells' sensitivity to anthocyanin. Another truth is , cancer cells will tolerate it after a long time of taking in anthocyanin. KLF4 downregulated in some cancer cells to help its cancer stem cell to escape from immune system, including lost sensibility to anti-cancer drug. That's why we can't use anthocyanin in clinical cancer therapy. Maybe, our work throw a little light in this dilemma, we can find a plant inside the cancer cells to cooperate with anthocyanin and destroy cancer cell.

In the future, we'll do more jobs about the molecular mechanism of anthocyanin and KLF4. We also finished constructing 5 mutants to explore the relation of KLF4 and anthocyanin.

References:

[1] Zhang ZF, Lu J, Zheng YL, et al. Purple sweet potato color attenuates hepatic insulin resistance via blocking oxidative stress and endoplasmic reticulum stress in high-fat-diet-treated mice.J Nutr Biochem. 2013,Jun 24(6):1008-18.

[2] Lu J, Wu DM, Zheng YL et al. Purple Sweet Potato Color Alleviates D‐galactose‐induced Brain Aging in Old Mice by Promoting Survival of Neurons via PI3K Pathway and Inhibiting Cytochrome C‐mediated Apoptosis . Brain Pathol. 2010 May;20(3):598-612.

[3] Capra hircus Kruppel-like factor 4 (KLF4) mRNA, complete cds.https://www.ncbi.nlm.nih.gov/nucleotide/1021691550?report=genbank&log$=nuclalign&blast_rank=10&RID=Z74WM35U015

Future Work

Compared with traditional chemotherapy, combining eating foods rich in anthocyanin with gene therapy has many advantages, such as no harm and lower cost in treatment. Since everybody's genes are different, we can treat patients one-to-one in gene therapy. In this way, we will get a more efficient result and we don't need to take medicine any more. We can take in anthocyanin from grapes, cherries, strawberries and some food that we can purchase easily.

Protocal

1.Molecular Cloning

Molecular cloning is a set of experimental methods in molecular biology that are used to assemble recombinant DNA molecules and to direct their replication within host organisms.

In the molecular cloning experiment, the KLF4 to be cloned is combined with vector DNA to generate recombinant DNA molecules. The recombinant DNA is then introduced into E. coli bacteria. This will generate a population of organisms in which recombinant DNA molecules are replicated along with the host DNA. This is single cell then can be expanded exponentially to generate a large amount of bacteria, each of which contain copies of the original recombinant molecule.

2.Cell culture

Cell culture is the complex process by which cells are grown under controlled conditions, outside their natural environment, an essential aspect of cloning technology. We can get a lot of cells or metabolites through cell culture.

Cell recovery

1. We put cryopreserved tubes in water bath pot (37℃) and shake it until cells dissolved. We can complete the thawing in 1-2 minutes.

2. Move cells into the centrifuge tube (5 ml).

3. Centrifugation for 5 minutes, 1000r/min.

4. After centrifugation, we discard the supernatant and move the precipitation to a petri dish.


Cell culture

1.Add 55ml serum and 6ml Penicillin-Streptomycin Solution to the medium.

2.Add the medium to the petri dish.


Cell collection

1.Digest cells with trypsin, then stop it with cell culture medium.

2.Remove the medium, then the cells sedimentated.

3.The cells are moved to a centrifuge tube and centrifuged for 5 minutes.

4.Discard the supernatant, and wash cells with PBS.

5.Centrifugation for 5 minutes, 1000r/min.

6.Discard the supernatant and cryopreservate the cells at -80℃.


3.Western blot

Western blotting uses specific antibodies to identify proteins that have been separated based on size by gel electrophoresis. The immunoassay uses a membrane made of nitrocellulose or PVDF (polyvinylidene fluoride). The gel is placed next to the membrane and application of an electrical current induces the proteins to migrate from the gel to the membrane. The membrane can then be further processed with antibodies specific for klf4, and visualized by using secondary antibodies detection reagents.


4.Cell Counting Kit-8

Cell Counting Kit-8 is based on WST-8 (chemical name: 2- (2-methoxy-4-nitro-phenyl) -3- (4-nitro-phenyl) -5- (2, 4-sulfophenyl) -2H- tetrazolium monosodium salt) which is widely used in drug screening, cell proliferation assay, cytotoxicity assay, tumor susceptibility testing and detection of biological activity and so on.


CCK-8 was produced by TransGen Biotech.

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