Salinomycin-loaded lipid-polymer nanoparticles with anti-CD20 aptamers selectively suppress human CD20+ melanoma stem cells.

Melanoma is the deadliest type of skin cancer. CD20+ melanoma stem cells (CSCs) are pivotal for metastasis and initiation of melanoma. Therefore, selective elimination of CD20+ melanoma CSCs represents an effective treatment to eradicate melanoma. Salinomycin has emerged as an effective drug toward various CSCs. Due to its poor solubility, its therapeutic efficacy against melanoma CSCs has never been evaluated. In order to target CD20+ melanoma CSCs, we designed salinomycin-loaded lipid-polymer nanoparticles with anti-CD20 aptamers (CD20-SA-NPs). Using a single-step nanoprecipitation method, salinomycin-loaded lipid-polymer nanoparticles (SA-NPs) were prepared, then CD20-SA-NPs were obtained through conjugation of thiolated anti-CD20 aptamers to SA-NPs via a maleimide-thiol reaction. CD20-SA-NPs displayed a small size of 96.3 nm, encapsulation efficiency higher than 60% and sustained drug release ability. The uptake of CD20-SA-NPs by CD20+ melanoma CSCs was significantly higher than that of SA-NPs and salinomycin, leading to greatly enhanced cytotoxic effects in vitro, thus the IC50 values of CD20-SA-NPs were reduced to 5.7 and 2.6 µg/mL in A375 CD+20 cells and WM266-4 CD+ cells, respectively. CD20-SA-NPs showed a selective cytotoxicity toward CD20+ melanoma CSCs, as evidenced by the best therapeutic efficacy in suppressing the formation of tumor spheres and the proportion of CD20+ cells in melanoma cell lines. In mice bearing melanoma xenografts, administration of CD20-SA-NPs (salinomycin 5 mg·kg-1·d-1, iv, for 60 d) showed a superior efficacy in inhibition of melanoma growth compared with SA-NPs and salinomycin. In conclusion, CD20 is a superior target for delivering drugs to melanoma CSCs. CD20-SA-NPs display effective delivery of salinomycin to CD20+ melanoma CSCs and represent a promising treatment for melanoma.

Targeted salinomycin delivery with EGFR and CD133 aptamers based dual-ligand lipid-polymer nanoparticles to both osteosarcoma cells and cancer stem cells.

We previously developed salinomycin (sali)-entrapped nanoparticles labeled with CD133 aptamers which could efficiently eliminate CD133+ osteosarcoma cancer stem cells (CSCs). However, sufficient evidences suggest that the simultaneous targeting both CSCs and cancer cells is pivotal in achieving preferable cancer therapeutic efficacy, due to the spontaneous conversion between cancer cells and CSCs. We hereby constructed sali-entrapped lipid-polymer nanoparticles labeled with CD133 and EGFR aptamers (CESP) to target both osteosarcoma cells and CSCs. The cytotoxicity of CESP in osteosarcoma cells and CSCs was superior to that of single targeting or nontargeted sali-loaded nanoparticles. Administration of CESP in vivo showed the best efficacy in inhibiting tumor growth than other controls in osteosarcoma-bearing mice. Thus, CESP was demonstrated to be capable of efficiently targeting both osteosarcoma CSCs and cancer cells, and it represents an effective potential approach to treat osteosarcoma.

Epidermal growth factor receptor aptamer-conjugated polymer-lipid hybrid nanoparticles enhance salinomycin delivery to osteosarcoma and cancer stem cells.

Osteosarcoma is a common childhood bone cancer with a poor survival rate. Osteosarcoma cancer stem cells (CSCs) contribute to the recurrence, drug resistance and metastasis of this disease. Previous evidence suggested that cancer cells are able to spontaneously turn into CSCs, thus it is crucial to simultaneously target osteosarcoma cells and CSCs. Our previous studies have demonstrated that salinomycin preferably eliminated osteosarcoma CSCs. In addition, amplification of the epidermal growth factor receptor (EGFR) is a common genetic aberration in osteosarcoma, and thus EGFR is a promising target in osteosarcoma. The present study aimed to develop EGFR aptamer-conjugated salinomycin-loaded polymer-lipid hybrid nanoparticles (EGFR-SNPs) to target both osteosarcoma cells and CSCs. The results revealed that EGFR was overexpressed in these cells, and that EGFR-SNPs possessed a small size of 95 nm, suitable drug encapsulation efficiency (63%) and sustained drug release over 120 h. EGFR-SNPs targeted EGFR-overexpressing osteosarcoma cells and CSCs, resulting in an enhanced cytotoxic effect compared with non-targeted SNPs and salinomycin. Notably, EGFR-SNPs was able to reduce the osteosarcoma tumorsphere formation rate and proportion of CD133+ osteosarcoma CSCs in the osteosarcoma cell lines more effectively compared with SNPs and salinomycin, suggesting that EGFR-SNPs effectively reduced the proportion of osteosarcoma CSCs. In conclusion, the interaction of EGFR aptamers and EGFR is a potential approach to promote the effective delivery of salinomycin to osteosarcoma. The study results suggested that EGFR-SNPs represents a promising approach to target osteosarcoma cells and CSCs.

Mannose-coated gadolinium liposomes for improved magnetic resonance imaging in acute pancreatitis.

BACKGROUND: Acute pancreatitis (AP) is an acute inflammatory condition of the pancreas. The symptoms, treatment, and prognosis of mild and severe AP are different, and severe AP is a potentially life-threatening disease with a high incidence of complications and high mortality rate. Thus, it is urgent to develop an effective approach to reliably discriminate between mild and severe AP. METHODS: We have developed novel gadolinium-diethylenetriaminepentaacetic (Gd-DTPA)-loaded mannosylated liposomes (named thereafter M-Gd-NL) that preferably target macrophages in AP. The targeting ability of M-Gd-NL toward macrophages in AP and its ability to discriminate between mild and severe AP were evaluated. RESULTS: The liposomes were of desired particle size (~100 nm), Gd-DTPA encapsulation efficiency (~85%), and stability. M-Gd-NL and non-targeted Gd-DTPA-loaded liposomes (Gd-NL) exhibited increased relaxivity compared with Gd-DTPA. Compared with Gd-NL and Gd-DTPA, M-Gd-NL showed increased uptake in macrophages, resulting in increased T1 imaging ability both in vitro (macrophage cell line) and in vivo (severe AP model). Importantly, M-Gd-NL had the ability to discriminate between mild and severe AP, as reflected by a significantly higher T1 magnetic resonance imaging signal in severe AP than in mild AP. M-Gd-NL did not show severe organ toxicity in rats. CONCLUSION: Our data suggest that M-Gd-NL had enhanced magnetic resonance imaging ability by targeting macrophages in AP and good ability to discriminate between mild and severe AP. We believe that M-Gd-NL could shed new light on the diagnosis of AP in the near future.

Self-targeted salinomycin-loaded DSPE-PEG-methotrexate nanomicelles for targeting both head and neck squamous cell carcinoma cancer cells and cancer stem cells.

AIM: To target both head and neck squamous cell carcinoma (HNSCC) cells and cancer stem cells (CSCs) by salinomycin-loaded DSPE-PEG-MTX (synthesized using DSPE-PEG2000-NH2 and methotrexate) nanomicelles (M-SAL-MTX). MATERIALS & METHODS: The characterization, antitumor activity and mechanism of M-SAL-MTX were evaluated. RESULTS & CONCLUSION: M-SAL-MTX showed enhanced inhibitory effect toward both HNSCC CSCs and non-CSCs compared with a single treatment of methotrexate and salinomycin. In nude mice-bearing HNSCC xenografts, M-SAL-MTX suppressed tumor growth more effectively than other controls including combination of methotrexate and salinomycin. Therefore, M-SAL-MTX may provide a strategy for treating HNSCC by targeting both HNSCC CSCs and HNSCC cells.

Polymer-Lipid Hybrid Theranostic Nanoparticles Co-Delivering Ultrasmall Superparamagnetic Iron Oxide and Paclitaxel for Targeted Magnetic Resonance Imaging and Therapy in Atherosclerotic Plaque.

Magnetic resonance imaging (MRI) combined with ultrasmall superparamagnetic iron oxide (USPIO) is effective for the detection of atherosclerotic (AS) plaque, and paclitaxel is effective for the treatment of AS. C11 is a polypeptide with high affinity and specificity for collagen IV. It is abundantly expressed in the outer layer of AS plaque. This study aimed to develop USPIO + paclitaxel-loaded polymer-lipid hybrid theranostic nanoparticles conjugated with C11 (UP-NP-C11) for simultaneous imaging and treatment AS plaque. UP-NP-C11 was developed by the nanoprecipitation method, and the theranostics of AS plaque by UP-NP-C11 were evaluated both in vitro and in the rabbit AS model. UP-NP-C11 was of desired particle size (140.2 nm), showed encapsulation efficiency of 35.5% and 55.2% for USPIO and paclitaxel, respectively, and had drug release profile. The accumulation of USPIO in Matrigel (containing abundant collagen IV) and macrophages coated on the Matrigel was significantly higher in the UP-NP-C11-treated group than in the group treated by UP-NP (USPIO + paclitaxel-loaded nanoparticles). Thus, UP-NP-C11 exerted better growth inhibitory effect and MRI ability in macrophages than UP-NP. Significantly, UP-NP-C11 showed better in vivo MRI ability and therapeutic effect in rabbit AS plaque than UP-NP and commercial USPIO + paclitaxel, and Prussian blue staining revealed significantly greater accumulation of USPIOs in the UP-NP-C11-treated group than in the control group. Furthermore, UP-NP-C11 did not cause severe toxicity to the rabbits. UP-NP-C11 represents a potential approach for targeted MRI and therapy in AS plaque.

Reproducibility of Middle Cerebral Artery Stenosis Measurements by DSA: Comparison of the NASCET and WASID Methods.

PURPOSE: To evaluate the intra- and inter-observer variability of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) criteria for the evaluation of middle cerebral artery (MCA) stenosis using digital subtraction angiography (DSA). MATERIALS AND METHODS: DSA images of 114 cases with 131 stenotic MCAs were retrospectively analyzed. Two radiologists and a researcher measured the degree of MCA stenosis independently using both NASCET and WASID methods. To determine intra-observer agreement, all the observers reevaluated the degree of MCA stenosis 4 weeks later. The linear relation and coefficient of variation (CV) between the measurements made by the two methods were assessed by correlation coefficient and multi-factor analysis of variance (ANOVA), respectively. Intra- and inter-observer variability of the two methods was evaluated by intraclass correlation coefficient (ICC), Spearman's R value, Pearson correlation coefficient and Bland-Altman plots. RESULTS: Despite the fact that the degree of MCA stenosis measured by NASCET was lower than measured using the WASID method, there was good linear correlation between the measurements made by the two methods (for the mean measurements of the 3 observers, NASCET% = 0.891 × WASID% - 1.89%; ICC, Spearman's R value and Pearson correlation were 0.874, 0.855, and 0.874, respectively). The CVs of both intra- and inter-observer measurements of MCA stenosis using WASID were significantly lower than that using NASCET confirmed by the multi-factor ANOVA results, which showed only the measurement methods of MCA stenosis had significant effects on the CVs both in intra- and inter-observer measurements (both P values < 0.001). Intra-observer measurements showed good or excellent agreement with respect to WASID and NASCET evaluation (ICC, 0.656 to 0.817 and 0.635 to 0.761, respectively). Good agreement for the WASID evaluation (ICC, 0.592 to 0.628) and for the NASCET evaluation (ICC, 0.529 to 0.568) was observed for inter-observer measurements. Bland-Altman plots demonstrated that the WASID method had better reproducibility and intra-observer agreement than NASCET method for evaluating MCA stenosis. CONCLUSION: Both NASCET and WASID methods have an acceptable level of agreement; however, the WASID method had better reproducibility for the evaluation of MCA stenosis, and thus the WASID method may serve as a standard for measuring the degree of MCA stenosis.