Targeted Drug-loaded Microbubbles Combining With UTMD For Diagnosis And Treatment Of Triple Negative Breast Cancer

At present,the treatment of triple negative breast cancer(TNBC)is a worldwide problem.It has been reported that the crucial reason of chemotherapy failure for TNBC is resistance to chemoradiotherapy and absence of effective targeted treatment.In previous studies,our research group had developed an novel and safe drug delivery system by the combination of ultrasound targeted microbubbles destruction(UTMD),RNA interference and Nanotechnology and reversed the drug resistance of HER2-positive breast cancer,which provides a promising tool for the targeted therapy of TNBC.However,specific treatment target,precise chemosensitization and imaging evaluation are needed for TNBC.As the first line drug,PTX,lacking of specific tumour targeting and the ability to be effectively internalized by TNBC cells,is still not effective on killing TNBC cells.X-box binding protein 1(XBP1)plays a very key role in the initiation,progression and relapse of TNBC,so blocking the expression of XBP1 gene is expected to curb the development and improve the prognosis of TNBC.The study is divided into two parts: in Part I,we designed a tumour targeted double-model microbubbles,PTX(paclitaxel)-loaded RGD-liposome microbubbles(PTX@RGD-MBs),combining UTMD to better diagnose TNBC and to improve the treatment effect.In Part II,our study aimed at X-box binding protein 1(XBP1)that is the specific treatment target of TNBC,prepared microcapsules carrying anti-EGFR and RGD and encapsulate Paclitaxel(PTX)and XBP1-si RNA.Through UTMD,the composite carrier went through blood vessel and target TNBC cells,and the XBP1-si RNA and PTX combined to inhibit TNBC cells,the precise chemosensitization was realized as a result and ultrasound contrast imaging was conducted to monitor and assess the treatment.The purpose of this study is to establish a new mode of adjuvant therapy in TNBC,which integrates not only effective and safe cell targeted chemotherapy but also a new real time target imaging method.PART I PTX-loaded RGD-liposome microbubbles(PTX@RGD-MBs)combining with UTMD for diagnosis and treatment of triple negative breast cancerPurpose: To investigate the diagnostic and therapeutic effect on TNBC of PTX-loaded RGD-liposome microbubbles(PTX@RGD-MBs)combining with UTMD.Material and methods: PTX@RGD-MBs were characterized with respect to size,zeta potential,and morphology.Cytotoxicity and drug loading capacity of PTX@RGD-MBs were analyzed.Cellular uptake,drug release profile,cells killing effects in vitro and imaging capability of PTX@RGD-MBs were assessed.Results: The PTX@RGD-MBs were uniformly spherical with a smooth surface without conjugation.The PTX@RGD-MBs exhibited an excellent drug encapsulation efficiency(EE %)of 91.07% and a drug loading(DL %)of 4.01% for PTX.PTX gradually released from PTX@RGD-MBs and exhibited sustained release patterns,UTMD prompted the MBs to rupture and rapidly release PTX.The liposome MBs had nearly negligible cytotoxicity towards MDA-MB-231 cells.PTX@RGD-MBs combining UTMD improved drug internalization and inhibited proliferation of MDA-MB-231 cells in vitro.In addition,PTX@RGD-MBs as a ultrsound contrast agent,produced high quality contrast enhanced ultrasound(CEUS)imaging in vitro and in vivo.Conclusions: PTX@RGD-MBs combining with UTMD could precisely diagnose TNBC and improve the curative effect to realize the integration of diagnosis and treatment of TNBC.PART II PTX-XBP1-si RNA-loaded EGF RGD-PLGA-PEG microbubbles((A-MBs-PTX-XS)combining with UTMD for diagnosis and treatment of triple negative breast cancerPurpose: To investigate the diagnostic and therapeutic effect on TNBC of PTX-XBP1-si RNA-loaded EGF RGD-PLGA-PEG microbubbles(EGF RGDMBs-PTXXBP1-si RNA,A-MBs-PTX-XS)combining with UTMD.Material and methods: A-MBs-PTX-XS were characterized with respect to size,zeta potential,and morphology.Cytotoxicity and drug(and si RNA)loading capacity of A-MBs-PTX-XS were analyzed.Cellular uptake,drug(and si RNA)release profile,cells killing effects in vitro and in vivo,toxic or side effects and imaging capability of A-MBs-PTX-XS were assessed.Results: The A-MBs-PTX-XS were uniformly spherical with a smooth surface without conjugation.The A-MBs-PTX-XS exhibited an excellent drug encapsulation efficiency(EE %)of 91.07% and a drug loading(DL %)of 4.01% for PTX.Meanwhile,the A-MBs-PTX-XS exhibited an excellent si RNA encapsulation efficiency(EE %)of 95.14% for XBP1-si RNA.PTX and XBP1-si RNA gradually released from A-MBs-PTX-XS and exhibited sustained release patterns,UTMD prompted the MBs to rupture and rapidly release PTX and XBP1-si RNA.A-MBs-PTX-XS combining UTMD improved drug and si RNA internalization,down-regulating the expression of XBP1 and inhibited proliferation of MDA-MB-231 cells in vitro and in vivo.A-MBs-PTX-XS possessed good biosafety and did not influence mice body weight and the normal structure of main organs.In addition,A-MBs-PTX-XS as a ultrsound contrast agent,produced high quality contrast enhanced ultrasound(CEUS)imaging in vitro and in vivo.Conclusions: A-MBs-PTX-XS combining with UTMD obviously improved the curative effect on TNBC and reduced toxic or side effects of PTX and XBP1-si RNA in vitro and in vivo.Meanwhile,A-MBs-PTX-XS could produced high quality CEUS imaging to realize the integration of diagnosis and treatment of TNBC.