Targeted Calcification Of Tumor Cells Induced By A Macromolecular Drug:Folate And Polysialic Acid Complex

Cancer is one of the biggest threats to human health,and chemotherapy is still the current first-line treatment.However,traditional chemotherapy always accompany numerous of serious side effects,which affect the quality of patients’ life significantly.In the past,we proposed a new strategy for cancer treatment – cancer cell targeted calcification.In order to induce calcification of tumor cells,mixture contained high concentration of calcium chloride needs to be injected locally.This goes against the principle of tumor-free technology,and may also lead to severe hypercalcemia,which severely limits the possibility of its clinical application.In this study,we linked polysialic acid to folate(folate-poly Sia).With the help of folic acid’s tumor cell targeting effect and polysialic acid’s calcium-enriching effect offered by the large number of carboxyl groups in the polymer chain,this particular macromolecular drug was able to induced calcification on the surface of tumor cell that highly express folate receptors.Formation of excellular calcification killed tumor cells and inhibited tumor metastasis.The first chapter introduced chemotherapy and its side effects,discussed the relation of biomineralization and cancer treatment.Here we also reviewed the recent medical applications of polymers,especially focusing on the structure,properties,physiological function and biological applications of polysialic acid.In the second chapter,the folate-polysialic acid cross-linked product was obtained mediated by tert-butyl-N-(2-aminoethyl)carbamate.The product was verified by ultraviolet visible light absorption spectrum,nuclear magnetic resonance spectrum and infrared absorption spectrum.We also calculated the cross-linking rate of the product.The third chapter confirmed the targeting effect of folate-poly Sia of tumors with high folate receptor expression.It was proved that folate-poly Sia induced calcification on the surface of tumor cells without additional calcium ions supplement.This kind of calcification occurred within the physiological range of phosphate and phosphate ions.We also found that tumor cell membrane calcification lead to tumor cell death.In Chapter 4,changes of calcification tumor cells were further studied,such as biological phenotype,energy metabolism and transcriptome differences.After calcification,the fluidity of the tumor cell membrane was significantly reduced.The migration and invasion ability of tumor cells were also weakened.The level of aerobic respiration and anaerobic glycolysis were reduced since two key enzymes in the glycolysis pathway were down-regulated after calcification.Transcriptome analysis showed that cell growth and metabolism were significantly affected.On the other hand,protein binding was severely disturbed.These phenomes suggested that calcification induced by folate-poly Sia killed tumor cells mainly through these two pathways.In Chapter 5,we constructed subcutaneous tumor and orthotropic tumor models.Through local injection into the tumor and systemic administration of folate-poly Sia,it was confirmed at the animal level that folate-poly Sia was able to inhibit tumor growth and prolong tumor-bearing survival time significantly.The survival time of mice is significantly better than the traditional chemotherapy drug such as doxorubicin,and the side effects are much more tolerable.In Chapter 6,a lung metastasis model was constructed.Studies have confirmed that folate-poly Sia significantly inhibited the ability of circulating tumor cells to form distant metastases.On the other hand,the metastasis ability of calcified tumor cells was significantly reduced.These results suggested that folate-poly Sia inhibited tumor metastasis as well.The last chapter was a summary of the full text.Herein we propose a first attempt of macromolecular-induced extracellular chemotherapy involving biomineralization by absorbing calcium from blood and develop a new type of drug,polysialic acid conjugated with folate,which selectively induces biogenic mineral formation on tumor cells and result in the pathological calcification of tumors.The macromolecule-initiated extracellular calcification causes cancer cell death mainly by intervening glycolysis process in cancer cell.Systemic administration of folate-poly Sia inhibited cervical and breast tumor growth and dramatically improved survival rates in mice.This complex has a better anti-tumor effects and fewer side effects than the traditional chemotherapy drug such as doxorubicin.This research provides a new strategy for the research of macromolecular anticancer drugs,and provides the possibility for the clinical transformation of tumor mineralization therapy.