Proteomic Analysis Of Proliferation Inhibition Of Docetaxel On Human Anaplastic Thyroid Cancer Cell Line (TA-K)

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive and lethalsolid tumors. ATC has the less sensitivity to various treatments on current.Proteome is all the protein in a cell or tissue. Proteomics study the rule of the lifeand activities in the overall protein level, to find the essence of life and theimportant physiological and pathological phenomena. Combining chemotherapy,radiotherapy, and surgery can improve the survival of ATC. Especiallychemoresistant is the emergency to solve. ATC can secrete some proteins whichcan expel chemotherapeutic agents out of the cell. This is one of the importantmechanisms of chemoresistant for ATC. Researchers suggest that paclitaxel maybe resistant to this action. The total effective rate and the rate of completeremission are higher than other chemotherapeutic agents. Docetaxel is a kind ofantitumor drug showing activity against various cancer types. Its concentration ofintracellular is three times of paclitaxel and the time of intracellular activity isthree times of paclitaxel. Docetaxel is likely to be a more effective chemotherapyagent to ATC. The purpose of this study is to observe the proliferation inhibitioneffect of Docetaxel on human anaplastic thyroid cancer cell(TA-K), withintegrated application of MTT, flow cytometry, proteomics and immunohistochemcalmethods. To study the mechanism of Docetaxel in TA-K cell lines, the changes of all kinds of biomolecules, with a view to the choice ofchemotherapy drugs and providing a basis for further studies.1. Proliferation inhibition effect of DocetaxelTo study the proliferation inhibition effect of Docetaxel on human anaplasticthyroid cancer cell (TA-K) with light microscopy, MTT and other methods. Thecytotoxicities were assayed with MTT to observe the killing effect on TA-K cellline. We obtain the primary parameters in vitro, that the concentration is 0.01μg/mL and the action time is 72 hours. The inhibition rate increased with times ina certain time. Docetaxel can induce and promote tubulin polymerizing intomicrotubules. At the same time, Docetaxel inhibit the tubulin depolymerization, toform stable microtubules and disrupt the normal regeneration of tubulin and themitosis. Cells can not form normal mitotic spindle, the division and proliferationwere inhibited. At the same time, Docetaxel can also inhibit the expression of bcl–2, c-myc and bcl - xl and promote the expression of Fas gene to induce theapoptosis.2. Proteomics analysis of Docetaxel in the TA-K cell lines.The proteins were extracted at the primary parameters in vitro of Docetaxelin the TA-K cell lines. We studied the dynamic changes in protein expressionusing 2-DE approaches. The experiment was repeated three times under the sameexperimental conditions. Then we chose the differrent points to identify theproteins with MALDI-TOF-MS. The results showed that:PARP,ADP-ribosepyrophosphatase,matrin 3, cell apoptosis susceptibility protein (CAS)wereup-regulated, hot shock protein (HSP)27 and an unnamed protein were downregulated.Through proteomic analysis of proliferation inhibition of Docetaxel,weachieved new ideas about the mechanism,including:①Docetaxel may lead toDNA damage, with the accumulation of a large number of PARP. At the same time. PARP lead ADP-ribose and ADP-PPase increased secondarily.②PARP,CAS, HSP27 regulate the expression of P53 and metabolism,promoting apoptosis.③With HSP27 down-regulated,the activity of DAXX increased,promotingapoptosis.④Docetaxel impact on chromatin organization, DNA replication,andRNA transcription, processing, and transport.⑤HSP27 associate with drugresistance. Docetaxel can down regulate HSP27,improve the sensitivity ofanticancer drugs in ATC. That CAS,PARP,HSP27 could become research targetand provide molecular basis on the treatment of ATC.