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αvβ3 integrin-specific exosomes engineered with cyclopeptide for focused supply of triptolide in opposition to malignant melanoma | Journal of Nanobiotechnology

Supplies and strategies


The supplies used on this research had been as follows: 1,2-distearoyl-sn-glycerol-3-phosphoethanolamine-[(polyethylene glycol)-2000]-c(RGDfK) (DSPE-PEG2000-cRGD) synthesized by Xi’an ruixi Organic Know-how Co., Ltd. (Xi’an, China); 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer (HEPES); CD63 (Abcam, 1: 1000, UK); CD9 (Abways 1:1000, China); TSG101 (Abways 1:1000, China); Cell Counting Package-8 (CCK-8, Yeasen Bio, China); Annexin V-APC/7-AAD Apoptosis Detection Package (YEASEN, China); 4′,6-diamidino-2-phenylindole (DAPI, Beyotime, China); PKH67 (Sigma, USA); DiR (Biotium, USA); Dulbecco’s modified Eagle’s medium (DMEM); Fetal bovine serum (FBS), Trypsin and 1% Pen-Strep (Thermo Fisher Scientific, Waltham, USA). Except in any other case said, different reagents and solvents had been bought from business sources and can be utilized with out additional purification.

Cell tradition

hUCMSCs had been derived from the umbilical wire of wholesome newborns delivered by cesarean part. The protocols had been accredited by the Institutional Assessment Board at Changhai Hospital of Naval Medical College. A375 and HaCaT cells had been bought from the Chinese language Academy of Sciences Cell Financial institution (Shanghai, China) and cultured in DMEM containing 10% FBS and 1% Pen-Strep beneath a 5% CO2 ambiance at 37 °C.


Male BALB/c nude mice (18–22 g) offered by Fudan College Shanghai Most cancers Heart had been housed beneath commonplace laboratory situations (25 °C, 50–60% humidity on 12 h mild/darkish cycles) with free entry to water and commonplace chow.

Culturing and characterization of hUCMSCs

Culturing of hUMSCs was carried out primarily based on earlier strategies [63]. Briefly, the hUC of wholesome newborns delivered by cesarean part was collected, washed with DMEM and 70% ethanol, after which reduce into small tissue lots (2–4 mm). Then, the tissue lots had been evenly organized within the tradition dish with gaps left and incubated with a normal tradition medium at 37 °C. When the fibroblast-like cells (hUCMSCs) climbed out from the sting of the tissue lots and reached 70–80% confluence, the cells had been trypsinized and ready for subculture. The standard protein markers (CD45, CD34, CD90, CD29, and CD44) of hUCMSCs at passage 3 had been detected by a circulate cytometer (BD Biosciences, USA) [64, 65].

Isolation and characterization of hUCMSCs-Exo

Exo was remoted from passages 3–10 hUCMSCs by gradient centrifugation [28]. When hUCMSCs reached 70%-80% confluence, the cells had been washed with PBS and cultured with 10% Exo-depleted FBS for 12 h. The harvested supernatant was ultracentrifuged at 300× g for 10 min, 2000× g for 10 min, and 10,000× g for 30 min at 4℃ to take away cells and cell particles. The supernatants had been then ultracentrifuged at 120,000× g for 70 min. The pellet was resuspended in PBS and ultracentrifuged once more at 120,000× g for an additional 70 min. Lastly, hUCMSC-Exo pellets had been resuspended in PBS and saved at −80 °C for additional use.

The morphology, dimension, dimension distribution, and zeta potential of hUCMSCs-Exo had been detected utilizing TEM (Hitachi, Tokyo, Japan) and dynamic mild scattering (DLS, Zetasizer Nano ZS90, Malvern, UK). As well as, western blotting evaluation was carried out to establish the exosomal markers CD9, CD63, and TSG101 of hUCMSCs-Exo. Briefly, the entire protein of hUCMSCs-Exo was detected by a BCA package, separated on a ten% sodium dodecyl sulfate–polyacrylamide gel, after which transferred onto polyvinylidene fluoride membranes. After blocking with 5% skimmed milk, the membranes had been incubated with CD9, CD63, and TSG101 major antibodies in a single day and horseradish peroxidase-conjugated (HRP) secondary antibodies. Lastly, the immunoblots on the membrane had been detected by enhanced chemiluminescence reagents (Amersham Pharmacia Biotech, Little Chalfont, UK) [42, 66].

DSPE-PEG2000-cRGD was integrated into Exo by the postinsertion methodology [42, 67]. Briefly, cRGD was dissolved in HEPES for 15 min at 60 °C to kind micelles. The micelles had been sonicated to cut back the scale to facilitate their separation from Exo. Exo labeled with PKH67 had been combined with the fashioned micelles at mass ratios (μg protein:μg protein) of 5:1, 1:1, 1:5, 1:10, and 1:15 for two h at 40 °C. After that, A375 cells had been handled with the above ready PKH67-labeled cRGD-Exo for six h. Then, the handled cells had been washed, trypsinized, and resuspended in PBS for circulate cytometry evaluation to display the ratio of cRGD and Exo primarily based on fluorescence depth. After that, the optimized Exo and cRGD micelles had been combined at 40 °C for two h after which uncovered to size-exclusion chromatography to purify cRGD-Exo.

Preparation and characterization of cRGD-Exo/TP

The coincubation methodology was utilized to load TP into cRGD-Exo. First, purified cRGD-Exo (600 μg/mL) and TP (40 μg/mL) at completely different mass ratios (μg protein:μg TP) of 10:1, 5:1, 1:1, 1:5, and 1:10 had been combined and incubated in a shaker at 100 rpm for 1 h at room temperature to organize drug-encapsulated exosomes, cRGD-Exo/TP. The unloaded drug was quantitated by HPLC to calculate DL and EE by the next Eqs. 1 and 2. Exo/TP was ready with the optimized prescription of cRGD-Exo/TP. The morphology, dimension, dimension distribution. and zeta potential of Exo/TP and cRGD-Exo/TP had been additionally characterised.

$${textual content{DL }}left( % proper) , = , left( {{textual content{Wt}} – {textual content{Wf}}} proper)/{textual content{Wm}} instances {1}00%$$


$${textual content{EE }}left( % proper) , = left( {{textual content{Wt}} – {textual content{Wf}}} proper)/{textual content{Wt}} instances {1}00%$$


the place Wt, Wf, and Wm characterize the burden of whole TP added, the burden of the unloaded TP, and the entire protein weight of cRGD-Exo, respectively.

Drug launch assay

The in vitro drug launch conduct of cRGD-Exo/TP was analyzed utilizing the dialysis methodology [68]. Briefly, 2 mL of cRGD-Exo/TP resolution was transferred right into a dialysis bag immersed in pH 7.4 or pH 5.5 PBS (containing 20% ethanol for sink situations) maintained at 37 ± 0.5 °C beneath 100 rpm shaking. 1 mL of launch medium was sampled and instantly changed with contemporary medium at 0.5, 1, 2, 4, 6, 8, 12, 24, 48, and 72 h for HPLC evaluation to calculate the cumulative launch p.c. The cumulative drug launch fee was calculated with the next Eq. (3):

$$E% = left[ {frac{{c_{n} }}{{{L mathord{left/ {vphantom {L {v_{2} }}} right. kern-nulldelimiterspace} {v_{2} }}}} + frac{{left( {c_{n – 1} + cdots c_{2} + c_{1} } right)v_{1} }}{L}} right] instances 100%$$


the place, the E% represents the amassed launch fee, Cn represents the TP focus of the nth pattern, L represents the TP content material of cRGD-Exo/TP added, and ν1 and ν2 characterize the volumes of the pattern and receiver medium, respectively.

Stability research

Storage stability and serum stability had been assessed by monitoring the particle dimension of cRGD-Exo/TP in PBS (4 °C, 7 days) or in 10% Exo-free serum (37 °C, 24 h). The dimensions of cRGD-Exo/TP in PBS was detected each day, and that in serum was detected at 2, 4, 6, 8, 10, 12, and 24 h.

In vitro internalization of cRGD-Exo/TP

A375 and HaCaT cells had been uncovered to PKH67-labeled Exo/TP or cRGD-Exo/TP for 4 h, after which the cells had been fastened with 4% paraformaldehyde and stained with DAPI. When the samples had been dried at room temperature at the hours of darkness, the mobile fluorescence depth was noticed with CLSM (Leica, Germany). As well as, for semiquantitative evaluation, the intracellular MFI of the cells with completely different therapies was calculated with ImageJ software program.

Moreover, TP taken up by A375 cells was additionally detected. After being handled with TP resolution, Exo/TP, and cRGD-Exo/TP (the focus of TP was 60 ng/mL) for various instances, A375 cells (residing cells) had been counted and lysed. The drug focus within the lytic cells was analyzed utilizing UHPLC-MS/MS.

Internalization mechanisms of cRGD-Exo/TP

A375 cells had been pretreated with numerous endocytic inhibitors or cultured at low temperature to probe the internalization mechanisms of cRGD-Exo/TP [45]. A375 cells incubated in 12-well plates had been pretreated with serum-free DMEM containing sodium azide (5 mg/mL), nystatin (50 μg/mL), chlorpromazine (5 μg/mL) and amiloride (50 μg/mL) for 1 h every. For the low-temperature group, the cells had been handled with serum-free DMEM at 4 ℃. Then, the cells had been washed with PBS and handled with 100 nM PHK67-labeled cRGD-Exo/TP for an additional 6 h at 37 °C. The cells cultured solely with cRGD-Exo/TP at 37 ℃ had been used as controls. The MFI of the PKH67 sign in numerous teams of cells was detected with circulate cytometry.

Cytotoxicity assay

A375 cells had been incubated with completely different concentrations of TP for twenty-four h. After that, 10 μL of CCK-8 was added to the handled cells and incubated for an additional 20 min. The absorbance was detected utilizing a microplate reader. After that, the cytotoxicity of Exo, cRGD-Exo, TP resolution, Exo/TP, and cRGD-Exo/TP was additionally evaluated (the focus of TP in TP resolution, Exo/TP, cRGD-Exo/TP was in line with the IC50 of TP on cells, and the protein focus of Exo was the identical as TP).

Invasion assays

A375 cells had been pretreated with Exo, cRGD-Exo, TP resolution, Exo/TP, and cRGD-Exo/TP for six h after which trypsinized and resuspended in DMEM. Then, the in another way handled cells had been incubated within the apical Transwell insert (24-well plant coated with Matrigel polycarbonate membranes, pore dimension 8 μm). In the meantime, 800 μL of DMEM with 10% FBS used for cell chemotaxis was added to the basolateral champers. After incubation for twenty-four h, the cells on the highest aspect of the apical chamber had been wiped, after which the migrated cells had been fastened with 4% paraformaldehyde and stained with 0.1% crystal violet. After that, 5 random fields beneath an inverted microscope had been visualized, and the migrated cells had been counted by ImageJ software program.

Cell apoptosis assay

To evaluate the proapoptotic impact of cRGD-Exo/TP on A375 cells, the cells had been incubated with Exo, cRGD-Exo, TP resolution, Exo/TP, and cRGD-Exo/TP for twenty-four h. Then, the cells had been trypsinized by pancreatic enzymes with out DMSO and resuspended in 500 μL 1× Binding Buffer. The cell suspension was stationarily cultured at room temperature for 15 min at the hours of darkness after including 7-AAD and Annexin V-APC. Subsequently, cell apoptosis and necrosis had been detected with a circulate cytometer.

Cell cycle assay

The cell cycle assay was carried out to discover the correlation between mitosis and cytotoxicity. Briefly, A375 cells had been incubated with DMEM, Exo, cRGD-Exo, TP resolution, Exo/TP, and cRGD-Exo/TP for twenty-four h. The handled cells had been then fastened with 70% ethanol for 12 h, washed with PBS 3 instances, and stained with propidium iodide/RNase A for 30 min. After that, the crimson fluorescence of in another way handled cells was recorded at 488 nm, and the DNA content material of cells was additionally analyzed.

Western blotting evaluation of apoptosis-related proteins

Western blotting was utilized to analyze the mechanisms of cell apoptosis. The apoptosis-related proteins (caspase 3, caspase 8, caspase 9, Bcl-2, Bax, cyto c, NF-κB, VEGF, and survivin) of A375 cells incubated with DMEM and cRGD-Exo/TP (70 ng/mL TP) had been detected by western blotting as described above.

In vivo biodistribution and pharmacokinetics of cRGD-Exo/TP

The xenograft tumor mannequin was established by subcutaneously injecting 2–4 × 106 A375 cells into the precise flank of male BALB/c nude mice. When the tumor quantity reached roughly 500 mm3, the mice had been randomized into 2 teams (n = 3) and injected intravenously with 0.2 mL of DiR-labeled Exo/TP or DiR-labeled cRGD-Exo/TP (600 μg/kg of TP). After injection, mice had been scanned at interval instances (1, 2, 4, 6, 12, and 24 h) utilizing an IVIS (Perkin-Elmer, USA) at 750/780 nm. Lastly, mice had been euthanized and surgically dissected at 24 h. The fluorescence depth within the coronary heart, liver, spleen, lung, kidney, blood, and tumors was additionally recorded.

The TP concentrations in blood, coronary heart, liver, spleen, lung, kidney, and tumor tissues had been additionally quantified over time. Briefly, 63 tumor-bearing nude mice had been randomly divided into 3 teams (n = 21): TP resolution, Exo/TP, and cRGD-Exo/TP. The preparations had been injected intravenously at drug-equivalent doses of 600 μg/kg TP. After injection, blood was sampled from the orbital vein at 5 min, 10 min, 15 min, 30 min, 1 h, 2 h, 4 h, 6 h, and 24 h. As well as, coronary heart, liver, spleen, lung, kidney, and tumor tissues had been collected at 5 min, 30 min, 1 h, 2 h, 4 h, 6 h, and 24 h. 9 mice had been sacrificed at every time level (n = 3), whereas at 10 min and 15 min, the mice had been solely taken for blood and weren’t killed. The TP focus in plasma and tissue homogenate was analyzed with UHPLC-MS/MS.

In vivo antitumor efficacy

The xenograft tumor mannequin mice had been randomized into 5 teams (n = 6): (1) regular saline, (2) cRGD-Exo, (3) TP resolution, (4) Exo/TP, and (5) cRGD-Exo/TP. The dosage of TP within the TP resolution, Exo/TP, and cRGD-Exo/TP teams was 600 μg/kg, whereas that of Exo within the cRGD-Exo, Exo/TP, and cRGD-Exo/TPgroups was additionally 600 μg/kg. The primary day was recorded as 0 d. Earlier than every dose, the size (L) and width (W) of the tumors had been measured to calculate tumor quantity (TV, TV = L × W2/2). After 8 doses (dosing each different day for 14 days), the mice had been sacrificed, after which the tumor tissues had been acquired, weighed, photographed, and stained for H&E, TUNEL assay, and Ki67 staining. The tumor inhibition fee was calculated utilizing Eq. (4). As well as, the survivorship curves had been additionally profiled based on the survival time of every group of mice (n = 6).

$${textual content{Tumor inhibition fee}}, = ,left( {{textual content{Wc}}, – ,{textual content{Wa}}} proper)/{textual content{Wc}}, instances ,{1}00%$$


the place, Wc and Wa point out the common weight of tumors within the management and administration teams, respectively.


The biosafety of cRGD-Exo/TP was additionally assessed primarily based on the “in vivo antitumor efficacy” experiment. Briefly, the mouse body weight of all teams was recorded all through the therapy interval. To guage systemic security, after the termination of therapy, the tissues of the guts, liver, spleen, lung, and kidney had been collected to calculate organ indexes [mass of the organ (mg)/bodyweight (g)] and to stain for H&E. As well as, orbital blood was sampled for a routine blood check, hepatic operate check and renal operate check, together with RBC, WBC, ALT, and Cr.

UHPLC-MS/MS evaluation

TP concentrations in cells, plasma, major organs, and tumors had been analyzed utilizing UHPLC-MS/MS (Thermo Fisher Scientific, CA, USA). The separation was carried out on an ACQUITY UPLCTM BEH C18 column (2.1 × 100 mm, i.d., 1.7 μm). The column temperature was maintained at 40 °C. The cellular phases had been 1% acetic acid aqueous resolution (A) and methanol (B). Isocratic elution with 40% A and 60% B was adopted at a circulate fee of 0.3 mL/mL. The temperature and circulate fee of dry gasoline (N2) had been 350 °C and eight L/min, respectively. The strain of the nebulizer gasoline (N2) was 40 psi. The capillary voltage was 4000 eV. The optimistic a number of response monitoring (MRM) mode was adopted to find out TP and carbamazepine (inside commonplace, IS). The collision power was 33 eV for each TP and IS. The precursor-to-product transitions had been m/z 361.1 → 105.2 for TP and m/z 237.1 → 194.0 for IS.

Statistical evaluation

The outcomes are introduced because the imply of not less than three experiments with the corresponding commonplace deviation (SD). Statistical knowledge had been analyzed utilizing SPSS software program, and a statistically vital distinction was denoted by the distinction likelihood degree (p < 0.05). The t-test and one-way ANOVA had been used to investigate the statistical knowledge.

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