Revealing The Nucleoside Transducers (NTs) Assembly On The Cell Membrane Using Small Molecular Probe Labeling

The human equilibrative nucleoside transporter 1(hENT1)is the most abundant and widely distributed membrane nucleoside transporter of human cells.Numerous nucleosides and nucleoside analogues are transported through membranes by hENT1.Considering the growing use of nucleoside analogues in cancer therapies,hENT1 has significant potential for use in the treatment of a variety of diseases.Studying hENT1’s function,distribution,and impact on the efficacy of those drugs is especially crucial.However,the distribution,assembly,and functional properties of hENT1 at the nanoscale cannot be studied using conventional imaging and labeling techniques.We developed chemical small molecule fluorescent probes that are better suited for high-quality super-resolution imaging in order to study the localization and assembly of hENT1 directly and precisely on cell membranes.Using direct stochastic optical reconstruction microscopy(d STORM),we were able to image hENT1 with high resolution at the nanoscale.We also systematically examined the assembly of hENT1on various cell surfaces and under various processing conditions,with the following key findings:1.A small molecular probe SAENTA-probe that is hENT1 inhibitor-type has been prepared.Through dual-color imaging of antibody probe and small molecule probe and dilazep substitution,we have verified the specificity of SAENTA-probe.We found that the SAENTA-probe’s small size and single binding site allow for a higher for higher labelling density(970±130/μm~2)and accuracy(17.94±7.49 nm),which makes it easier to take accurate images of the assembly of hENT1 on the membrane.2.Details of hENT1 assembly are revealed by small molecule-based d STORM.Although hENT1 tended to be organized in clusters on various surfaces,our analysis of its distribution on the apical and basolateral membranes of MDA-MB-231 cells revealed that the apical membrane exhibited 23.75%and 25.86%higher hENT1 point density and cluster area,respectively.We suggest that hENT1 is primarily in the role of nucleoside transport through the apical membrane of cells exposed to the culture system,and that larger,tightly assembled hENT1 clusters are more effective at realizing its transport capacity.By contrasting the effects of glycosylated chains,lipid rafts,and epithelial cell adhesion molecule(Ep CAM)on hENT1 assembly,we further revealed variations in the potential mechanisms of hENT1 assembly on different surfaces.We discovered that lipid rafts and glycosylated chains are more closely associated with apical membrane hENT1,while Ep CAM is more closely associated with basal membrane hENT1.3.We found differences in the distribution of hENT1 on the membrane due to variations in the nucleoside requirements of the cells by comparing the distribution details of hENT1 on normal and cancer cells.It is interesting to note that,depending on their progression,cancer cells from the same tissue might exhibit distinct assembly in the distribution of hENT1 on their membrane.Under environmental and drug starvation conditions,it was found that the distribution of hENT1 on cell membrane was dramatically reduced at 60.72%and 72.98%,respectively.We believe that when cells stop dividing or experience cellular activity damage,the decreased need for genetic material synthesis slows down the translocation of nucleoside material,reducing the dispersion and clustering tendency of membrane hENT1.This implies that the distribution of hENT1 and its function are correlated.Also,it may be possible to determine the cellular state by observing its specific assembly of hENT1 in various cell states.4.We further investigated the potential relationship between changes in hENT1assembly and the efficacy of anticancer drugs because the distribution of hENT1 may influence the drug absorption and treatment efficacy.Gemcitabine(Gem)and 5-fluorouracil(5-FU)were tested for their different effects on MDA-MB-231 and MCF-7cells.Gem had a stronger influence on the cluster distribution of hENT1 on MDA-MB-231,where it decreased by 66%,but 5-FU had a stronger influence on the cluster distribution of hENT1 on MCF-7 cells,where it increased by 151%.We have provided the drug combination for each two cells in accordance with the features of the actions of the various pharmaceuticals on the different cells.The results indicated that Gem+C2-Cer is superior for MDA-MB-231,which is a 34%decrease from Gem treated 69%.MCF-7 respond better to sequential 5-FU and Gem treatments,which is a 34%reduction from Gem treatment.We investigated the assembly of hENT1 for the first time using small molecule labeling d STORM imaging,which showed several potential hENT1 assembly features on different cell membranes.We also noticed a connection between the hENT1 assembly and the cellular life state,and we used this discovery to observe drug efficacy.Based on changes in the hENT1 assembly,we came up with a combination of drugs for the two different types of cells,respectively.