Design,Preparation And Activities Of New Dual-targeted Platinum Antitumor Agents

Cisplatin is a chemotherapeutic drug which is widely used in clinic.It can effectively treat head and neck cancer,ovarian cancer,testicular cancer,non-small cell lung cancer,cervical cancer and other malignant tumors.However,drug resistance and side effects seriously hinder the development of platinum drugs in clinic.Objective:In order to overcome the limitation of cisplatin,we designed and synthesized novel dual-target platinum antineoplastic drugs by introducing small functional drugs based on the theory of prodrug,in order to own synergistic anti-cancer function and reduce the toxicity of platinum drugs.Method:Part I:The studies on the preparation and activities of new platinum anti-tumor drugs based on etodolac.Etodolac is a kind of cyclooxygenase inhibitor that is liposoluble.Etodolac was introduced to the design of Pt drug,in order to achieve dual-target?COX-2 and DNA?therapeutic effect.And Liposome delivery system was used to improve the efficacy of platinum and reduce toxicity.The new Pt?II?-ETO was synthesized from etodoac and cisplatin by coordination reaction.The structures of the compounds were analyzed and characterized by ¹H-NMR,¹³C-NMR and HRMS.According to the high hydrophobicity of the compounds,nano-delivery liposomes was selected to improve drug uptake of Pt?II?-ETO and reduce the toxicity of cisplatin.The particle size,zata potential,PDI value and surface morphology of Pt?II?-ETO-LP were characterized by malvern diffraction particle size analyzer and electron transmission electron microscopy.Ultraviolet-visible spectrophotometry,dialysis membrane diffusion and dynamic light scattering method was used to determine the entrapment efficiency,drug loading rate,release rate and stability of Pt?II?-ETO-LP,respectively.MTT assay was used to study anti-tumor activity of Pt?II?-ETO and its liposome Pt?II?-ETO-LP.Part II:Preparation and activity of new tetravalent platinum anticancer drugs based on gemcitabine.According to GP regimen for the first-line treatment of non-small cell lung cancer,we designed and synthesized a novel tetravalent platinum anticancer prodrug based on gemcitabine.Palmitic acid and gemcitabine were introduced into the two axial positions of Pt?IV?,respectively.Palmitic acid can enhanced the fat solubility of the prodrug to promote drug uptake,and played a synergistic effect of gemcitabine and cisplatin,to improve the therapeutic effect of non-small cell lung cancer.The tetravalent platinum prodrug GPt^IVC₁₆6 based on gemcitabine was synthesized by six-step chemical reaction.The structures of the compounds were characterized by ¹H NMR,¹³C NMR and high resolution mass spectrometry.The self-assembled nanoparticles PGNs were prepared based on the amphiphilic structure of GPt^IVC₁₆,and their particle size,zeta potential,PDI value and morphology were characterized by malvern diffraction particle size analyzer and electron transmission electron microscopy;MTT assay was used to test the growth inhibition activity of GPt^IVC₁₆;HPLC was used to determined the reduction of prodrugs that was reduced by Ascorbic Acid and Glutathione;Flow cytometry was used to determine the effect of GPt^IVC₁₆6 on cell cycle;Laser confocal microscopy was used to detect the effect of inducing DNA double-strand breaks in cancer cells by GPt^IVC₁₆;Annexin V-FITC/PI was used to detect the apoptotic induction of GPt^IVC₁₆6 on tumor cells.Results:Part I:Preparation and activities of new platinum anti-tumor drugs based on etodolac.Pt?II?-ETO antineoplastic drug?purity?95%?was successfully designed and synthesized,and Pt?II?-ETO-LP was successfully prepared.The ratio of drug-lipid of the liposomes was 1:5.The average particle size was 203 nm.The zeta potential was–16.6 mv.The PDI value was 0.226.The encapsulation rate was 95.6%.The drug loading rate was 13.74%,and the stability was good.Under transmission electron microscopy,the nanoparticles were uniformly distributed in the shape of spheres with a diameter of about 200 nm.The release rate of Pt?II?-ETO-LP in PBS medium was about 43%in 24 hours.In breast cancer cell MDA-MB-231,the antineoplastic activity of Pt?II?-ETO and its liposome Pt?II?-ETO-LP were higher than that of cisplatin,and decrease significantly the cytotoxicity in normal cell line LO2.Compared with Pt?II?-ETO,its liposome Pt?II?-ETO-LP has better tumor growth inhibition and lower normal cell cytotoxicity.Part II:Preparation and activity of new tetravalent platinum anticancer drugs based on gemcitabine.GPt^IVC₁₆6 was successfully synthesized with purity?95%.The self-assembled nano PGNs was prepared from GPt^IVC₁₆.The average particle size of the nanostructure was 98 nm,the zeta potential value was–19.8 mv,and the PDI value was 0.217.The surface morphology of the nanoparticles was uniform spherical.GPt^IVC₁₆6 can release gemcitabine and cisplatin in the presence of ascorbic acid.GPt^IVC₁₆6 showed better antitumor activity than gemcitabine.In A549,MCF-7,HeLa and HepG-2 tumor cells,GPt^IVC₁₆6 showed better anti-tumor activity than cisplatin.Especially in non-small cell lung cancer A549 cells,the growth inhibition of GPt ^IVC₁₆6 was 38 times higher than that of cisplatin.Conculsion:The work successfully designed and synthesized a new bivalent platinum antineoplastic drug Pt?II?-ETO and its drug-loaded liposome Pt?II?-ETO-LP based on etodolac,and a new tetravalent platinum antineoplastic drug GPt^IVC₁₆6 based on gemcitabine and its self-assembled nano PGNs.The results showed that both Pt?II?-ETO-LP and GPt^IVC₁₆6 increased the antineoplastic activity of platinum and effectively reduced the toxicity of platinum drugs in normal cells.