Targeted theranostics of lung cancer: PD-L1-guided delivery of gold nanoprisms with chlorin e6 for enhanced imaging and photothermal/photodynamic therapy

Peptide modified nanoparticles have emerged as powerful tools for enhanced cancer diagnosis and novel treatment strategies. Here, human programmed death-ligand 1 (PD-L1) peptides were used for the first time for the modification of gold nanoprisms (GNPs) to enhance targeting efficiency. A multifunctional nanoprobe was developed that the GNPs@PEG/Ce6-PD-L1 peptide (GNPs@PEG/Ce6-P) was used for imaging-guided photothermal/photodynamic therapy by using the targeting effect of PD-L1. Both confocal imaging and flow cytometry experiments demonstrated a remarkable affinity of the as-prepared nanoprobes GNPs@PEG/Ce6-P to lung cancer cells (HCC827), which have a high PD-L1 expression. Subsequent in vitro and in vivo experiments further demonstrated that the nanoprobes GNPs@PEG/Ce6-P not only allowed for real-time visualization via fluorescence (FL) imaging and photoacoustic (PA) imaging, but also served as phototherapy agents for synergistic photothermal therapy (PTT) and photodynamic therapy (PDT). Furthermore, treatments on human lung cancer cells-derived tumors demonstrated that the nanoprobes GNPs@PEG/Ce6-P could significantly suppress tumor growth through PTT and PDT from GNPs and Ce6, respectively. In conclusion, the as-prepared new nanoprobes show promising potential for nanomedicine with remarkable targeting ability for dual-mode imaging and enhanced PDT and PTT effects on lung cancer.

Effects of gold nanoprism-assisted human PD-L1 siRNA on both gene down-regulation and photothermal therapy on lung cancer

Gold nanoprisms (GNPs) have been broadly studied for the potential applications in both imaging and treatment on tumors due to their special characteristics. Herein we reported that a new nanoplatform GNPs@PSS/PDADMAC-siRNA (GNPs-siRNA) was designed and fabricated by sequentially coating the GNPs with poly (sodium 4-styrenesulfonate) (PSS) and poly (-diallyldimethylammonium chloride) (PDADMAC) to carry small interfering RNA (siRNA). Human program death-ligand 1 (PD-L1) was recently known to be crucial for cancer cell survival through the intrinsic signaling activities, besides serving as an important checkpoint gene in immune system. We successfully attached the human PD-L1 siRNA to the surface of GNPs@PSS/PDADMAC to obtain the GNPs-hPD-L1 siRNA nanoplatform. Real Time Cellular Analysis (RTCA) assay demonstrated that GNPs-hPD-L1 siRNA exhibited remarkable capacity to inhibit the proliferation of human lung cancer cells. Subsequent in vitro and in vivo experiments verified that the GNPs-hPD-L1 siRNA not only functioned as a carrier for siRNA delivery to down-regulate the hPD-L1 expression, but also served for photoacoustic (PA) imaging and photothermal agents for photothermal therapy (PTT) in both human lung cancer cells and human lung cancer cells-derived tumors. Our findings could be expected to provide an innovative direction for future clinical transformation application. STATEMENT OF SIGNIFICANCE: To our knowledge, this is the first paper related to the hPD-L1 siRNA delivery combined with the gold nanoparticles, especially the gold nanoprisms. The as-prepared GNPs-hPD-L1 siRNA nanoplatform not only functioned as a carrier for siRNA delivery to down-regulate the PD-L1 expression, but also acted as photothermal agents for theranostic effects in both human lung cancer cells and human lung cancer cells-derived tumors. The as-prepared GNPs-hPD-L1 siRNA nanoplatform could knock down human PD-L1 gene expression, which caused the inhibition on proliferation of human lung cancer cell in vitro or in vivo. The as-prepared GNPs-hPD-L1 siRNA nanoplatform possessed excellent photoacoustic imaging ability and photothermal therapy effects.

Dual-Targeted Gold Nanoprism for Recognition of Early Apoptosis, Dual-Model Imaging and Precise Cancer Photothermal Therapy

Photothermal therapy as novel strategy to convert near-infrared (NIR) light into heat for treatment cancers has attracted great attention and been widely studied. However, side effects and low efficiency remain the main challenge of precise cancer photothermal therapy. Methods: In this study, we have successfully fabricated and characterized the dual-targeted gold nanoprisms, whereby bare gold nanoprisms (Au NPR) were conjugated to a phenanthroline derivatives-functionalized tetraphenylethene (TPE) and further stabilized with target peptide aptamers via Au-S bonds (Au-Apt-TPE). Then, the remaining nitrogen atoms of the Au-Apt-TPE could effectively chelate with Zn²⁺ ions (Au-Apt-TPE@Zn) for monitoring early stage apoptotic cells. Results: The as-synthesized Au-Apt-TPE@Zn exhibited good monodispersity, size stability and consistent spectral characteristics. TPE synthesized here showed aggregation-induced emission (AIE) characteristics, and zinc conjunction (TPE@Zn) endowed Au-Apt-TPE@Zn with the cell membrane-targeted ability to selectively recognize the membranes of early stage apoptotic cells but not respond to healthy cells, which provided valuable diagnosis information on therapeutic efficacy. Au-Apt-TPE@Zn achieved specifically nuclear-targeted ability by surface decoration of AS1411 DNA aptamer. Au-Apt-TPE@Zn under NIR irradiation showed effective photothermal therapy against SGC-7901 human gastric carcinoma cells growth in vitro by inducing apoptosis through triggering reactive oxygen species (ROS) overproduction and regulating multiple signal crosstalk. In vivo studies revealed that Au-Apt-TPE@Zn under NIR irradiation showed deep penetration and dual-model imaging application (cancer-targeted fluorescence imaging and light-up photoacoustic imaging). Au-Apt-TPE@Zn under NIR irradiation also displayed strong photothermal therapy against gastric carcinoma xenograft growth in vivo by induction of apoptosis. Importantly, analysis of histopathology, hematotoxicity and immunocytotoxicity indicated that Au-Apt-TPE@Zn had less side effect and high biocompatibility. Conclusions: Our findings validated the design of using Au nanoprism with AIE materials and dual-targeted decoration could be an effective strategy in recognition of early apoptosis, dual-model imaging and precise cancer photothermal therapy.

Multiparametric analysis of anti-proliferative and apoptotic effects of gold nanoprisms on mouse and human primary and transformed cells, biodistribution and toxicity in vivo

Background

The special physicochemical properties of gold nanoprisms make them very useful for biomedical applications including biosensing and cancer therapy. However, it is not clear how gold nanoprisms may affect cellular physiology including viability and other critical functions. We report a multiparametric investigation on the impact of gold-nanoprisms on mice and human, transformed and primary cells as well as tissue distribution and toxicity in vivo after parental injection.

Methods

Cellular uptake of the gold-nanoprisms (NPRs) and the most crucial parameters of cell fitness such as generation of reactive oxygen species (ROS), mitochondria membrane potential, cell morphology and apoptosis were systematically assayed in cells. Organ distribution and toxicity including inflammatory response were analysed in vivo in mice at 3 days or 4 months after parental administration.

Results

Internalized gold-nanoprisms have a significant impact in cell morphology, mitochondrial function and ROS production, which however do not affect the potential of cells to proliferate and form colonies. In vivo NPRs were only detected in spleen and liver at 3 days and 4 months after administration, which correlated with some changes in tissue architecture. However, the main serum biochemical markers of organ damage and inflammation (TNFα and IFNγ) remained unaltered even after 4 months. In addition, animals did not show any macroscopic sign of toxicity and remained healthy during all the study period.

Conclusion

Our data indicate that these gold-nanoprisms are neither cytotoxic nor cytostatic in transformed and primary cells, and suggest that extensive parameters should be analysed in different cell types to draw useful conclusions on nanomaterials safety. Moreover, although there is a tendency for the NPRs to accumulate in liver and spleen, there is no observable negative impact on animal health.

Electronic supplementary material

The online version of this article (10.1186/s12989-017-0222-4) contains supplementary material, which is available to authorized users.