Detection Of Serum Anti-p53Antibody In Cancer Patients And The Regulation Of Angiogenesis Factors Under The Pressure Of Tumor Microenvironment

Part oneTumorigenesis is imperceptible initially. Many cancer patients have lost theiroptimal therapeutic time when they were diagnosed. Actually, certain approaches cansolve this promblem, such as the serological detection methods, which is hopefullyable to reveal the existence of tumor cells.Serum anti-p53antibody (s-p53Ab) is proved to correlate with the p53genemutation and the aberrant p53protein accumulation. It is considered a potentialvaluable tumor serological biomarker and a reflection of oncogenesis, tumordevelopment, tumor deterious as well as chemoresistance. To date, the commonmethod that uses in the detection of s-p53Ab is enzyme-linked immunosorbent assay(ELISA). However, the detection rate of the traditional ELISA is far beyondsatisfactory, owning to the different structure of the antigen using in such systemcompared to the natural p53protein in the body of human being, and the falsenegative exists. Besides, the cost of preparation and purification of this sort of proteinis high.With phage displaying technology, certain kind of protein or peptide can bedisplayed on the surface of filamentous phage. Because peptide of this sort is able tomimick the structure of natural protein, it has high antigenicity. Moreover, thepurification of filamentous phage is quite easy and lowcost.In current study, we creatively unified the p53-ELISA and phage-ELISA, whichused the recombined wild type p53and hybrid phage protein as antigens respectively,and constructed the p53-phage ELISA. Using this system, the s-p53Ab of829cancerpatients including lung, breast, colorectal, gastric, esophageal, liver and ovariancancer were detected. The result revealed that the highest positive s-p53Ab detectionrate was ovarian caner, while the lowest was liver cancer. The detection rate of s-p53Ab in p53-ELISA was25.6%(212samples), and that of phage-ELISA was19.9%(165samples), p53-phage ELISA was35.9%(298samples). Further more, we foundthat the level of s-p53Ab correlated with several clinicopathological parameters ofcancer patients. Specially, it is found that the s-p53Ab level decreased along with thealleviation of patients’ condition, and those who overexpressed s-p53Ab before therapy often showed chemoresistance.To sum up, the p53-ELISA and phage-ELISA compensate each other well, and thep53-phage ELISA has an edge over any single detection system. The surveillance ofs-p53Ab may probably provide a good diagnostic and therapeutic scheme for cancerpatients. Part twoWhichever during the wound repair or tumorigenesis, microenvironments change isthe main inducingfactor of angiogenesis, because the tissues or cells may generate thebacklash to these change in order to survive and develop in the harsh environment.The internal environment that tumor cells exist in is complex, and the hypoxia, highcell density and serum starvation are three common conditions. To keep proliferatingand metastasis, tumor needs more oxygen and nutrient which are supported by newblood vessels.Angiogenin (ANG), vascular endothelial growth factor (VEGF) and basic fibroblastgrowth factor are three important angiogenesis. They not only regulate the cellproliferation and angiogenesis/vascularization, but also cooperate and interact witheach other. However, the mechanism of such cooperation and interaction, till now, isnot quite clear, especially in the microenvironment of hypoxia, high cell density andserum starvation, and little report was seen.To fill this research gap, we superficially investigated the expression of thereangiogenesis mentioned above under the suppression of hypoxia, high cell density andserum starvation. We found that the human being prostate cell line PC-3(p53null)expressed higher level of ANG and VEGF, as well as lower level of bFGF by thestimulation of hypoxia and high cell density than normal did. The transfection ofpCI.neo-ANG or pCI.neo-VEGF could not induce the up-regulation of bFGF.Otherwise, the introduction of p53into PC-3cell could not inhibit the expression ofANG, VEGF or bFGF whatever in normoxia or hypoxia, although it was reportedplaying an important role in hypoxic stimulation.For this, we set up a hypothesis that there possibly exists an unknown negativefeedback mechanism between the angiogenesis and hypoxia-inducing factor. Besides,the regulation function of p53in PC-3cell could be different from other cells. Wehope current superficial work would pave a way for further investigation.