Nanodiamonds-Mediated Multimode Approaches For Triple Negative Breast Cancer Therapy

Breast cancer is the commonest female cancer worldwide threatening women health and the incidence of breast cancer has increased over the past decades.Triple negative breast cancer(TNBC)is a complex and the most aggressive subtype of breast cancer,accounting for 15%-25% of breast cancer.Due to the lack of therapeutic targets,surgery,chemotherapy and radiotherapy are the primary approaches for clinical treatment of TNBC,in which the resistance to the chemotherapy and toxicity of radiotherapy are remained to be solved.Thus,precise,targeted and combined therapeutic approaches are urgently needed for effective TNBC treatment.Following the recent development of nano-medicine,nano-drugs which encapsulates multi-drugs with combined therapeutic approaches have improved antitumor outcomes.Moreover,various multifunctional nanocarriers were designed for precise,targeted tumor therapy with imaging potential.Nowadays,multifunctional nanoplatform have attracted considerable research interest.Among the nanocarriers exploited so far,nanodiamonds(NDs),which are the inorganic nanomaterials is an ideal nanocarrier due to their good biosafety,drug loading ability and capacity to encapsulate both active small molecules and biomacromolecules for enhanced therapeutic efficacy.Moreover,NDs could be used as a safe and potent autophagic inhibitor to allosterically improve the therapeutic efficacy of the treatment of solid tumors.In this thesis,we constructed a series of drug loaded nanocomplexes based on the nanodiamonds using self-assembly approach for the efficient combination therapy against TNBC.Experiments both in vitro and in vivo were carried out to verify the synergistic anti-tumor effects of various nanocomponents.The detailed work is described as below:1.NDs-based nanoplatform was constructed to integrate cytotoxic peptides mitochondria tarigeting peptide(KLAK)and glucose oxidase(GOx)into a single nanoplatform KNDG via a noncovalent self-assembly approach for synergistic metabolic therapy of TNBC.The size,zeta potential,morphology and optional properties were characterized.The results revealved that KNDG had a uniform nanostructure,with good dispersity in water and exhibitied excellent catalytic capacity for glucose.In vitro study,KNDG showed enhanced cellular uptake and the ability of targeting mitochondria.Furthermore,KNDG exhibited superior cell killing effects and pro-apoptosis capability on MDA-MB-231 cells.Western-blot,JC-1 analyse and ATP assay results revealved that KNDG could cause the disruption of mitochondria and increase the consumption of glucose,resulting in a severe depletion of ATP,leading to the synergistic tumor inhibition effects.Anti-tumor results in vivo revealed the superior tumor inhibition effects of the combination therapy group KNDG with good biocompatibility.2.We constructed the theranostics nanoplatform for the precise therapy against TNBC.We encapsulated the photosensitizer(IR780)and anti-cancer drug(Ursolic acid,UA)into a single nanoplatform(PNDUI)through one-step assembling approach based on the noncovalent interactions between protamine(PS)and NDs for fluorescence imaging-guided photodynamic/UA combination therapy of TNBC.The resulting PNDUI had uniform sizes,good colloidal stability and excellent fluorescence properties.Moreover,PNDUI dispersed in deionized water had excellent capability of the reactive oxygen species(ROS)production under near-infrared irradiation(NIR)irradiation.We found that PNDUI could be uptaken by MDA-MDA-231 cells and under NIR irradiation,which could be triggered to exhibit PDT effects.Then a series of cellular experiments were carried out to investigate the anti-cancer effects of PNDUI.The relevant results verified that PNDUI could be triggered to exhibit PDT/UA combination therapeutic effects,leading to tumor apoptosis as well as inhibition of cell proliferation and migration.Furthermore,the biodistribution and accumulation of PNDUI in vivo could be monitored by fluorescence imaging(FL).The FL results revealed that PNDUI could prolong the drug circulation and enhance the tumor targeting ability.Meanwhile,compared with mono-therapy,PDNUI exhibited the highest tumor inhibition rate.Finally,we investigated the biosafety of nanocomplexes through H&E staining and blood analysis,the results of which confirmed that PNDUI showed effective therapeutic outcomes with good biocompatibility.3.Finally,layer-by-layer self-assembly approach was utilized to construct the tumor targeting theranostics nanoplatform based on NDs for mild-temperature photothermal and chemo combination therapy.First,NDs were modified with protamine sulphate(PS).Meanwhile,photosensitizer Indocyanine green(ICG)and HSP70 small molecule inhibitor Apoptozole(APZ)could be synchronously incorporated to form positive charged PS@NDs(ICG + APZ).Then negative charged hyaluronic acid(HA)was assembled onto the outer face of PS@NDs(ICG + APZ)to form NPIAs.Finally,positive charged small molecule anti-cancer drug Doxorubicin(DOX)could be adsorbed onto the surface of NPIAs through electrostatic interactions(NPIADs).The final nanocomplex NPIADs exhibited excellent photothermal stability and conversion efficiency.Then a series experiments revealed that NPIADs could be triggered by NIR laser irradiation to exhibit an enhanced mild-temperature photothermal therapy effects via suppressing the expression of HSP70 and combined with chemotherapy.Subsequently,the sensitivity of MDA-MB-231 cells could be significantly improved through the weakening of the thermal/drug resistance via autophagy inhibition,leading to augmented combination therapy efficiency in vitro.Furthermore,the NPIADs could be used as a theranostic nanoplatform for fluorescence(FL)and photoacoustic(PA)imaging.The results confirmed the higher accumulation behavior at tumor sites and superior anti-tumor efficiancy which was attributed to the tumor targeting and synergistic tumor inhibition effects of NPIADs.Finally,the biosafety analysis also revealed the good biocompatibility of NPIADs in vivo.In summary,ND-mediated multimode combination therapy exhibits remarkable anti-tumor efficiency,which provides novel method and strategy in precise therapy against TNBC.