Plasma membrane targeted photodynamic O2 economizer for hypoxic tumor therapy.

The development of photodynamic therapy (PDT) is severely limited by short half-life of singlet oxygen (1O2) and the hypoxic microenvironment. In this work, a plasma membrane targeted photodynamic O2 economizer (designated as P-POE) is developed to improve the subcellular delivery of photosensitizers and alleviate the tumor hypoxia for enhanced PDT effect. After self-assembly into nanomicelles, P-POE has a relatively high stability and a favorable photochemical performance, which are conducive to boosting the 1O2 production. Besides, the plasma membrane anchoring of P-POE contributes to enhancing the preferential retention and cellular accumulation of photosensitizers on tumor tissues and cells. More importantly, P-POE-induced mitochondrial respiratory depression is demonstrated to reduce the O2 consumption of tumor cells to relieve the hypoxia. Consequently, P-POE still exhibits a robust PDT effect against hypoxic tumors, which greatly inhibits the proliferation of breast cancer with low adverse reactions. This innovative combination of subcellular targeting and hypoxic alleviation would advance the development of individualized drug delivery systems for photodynamic therapy against hypoxic tumors.

Tumor targeted self-synergistic nanoplatforms for arsenic-sensitized photodynamic therapy.

Development of antitumor agents with high efficiency and low toxicity is one of the most important goals for biomedical research. However, most traditional therapeutic strategies were limited due to their non-specificity and abnormal tumor microenvironments, causing a poor therapeutic efficiency and severe side effects. In this paper, a tumor targeted self-synergistic nanoplatform (designated as PAO@PCN@HA) was developed for chemotherapy sensitized photodynamic therapy (PDT) against hypoxic tumors. The efficient drug loading of phenylarsine oxide (PAO) in porphyrinic metal organic framework of PCN-224 as well as the surface modification of hyaluronic acid (HA) improved the targeted drug delivery and reduced the side effects of PAO at the therapeutic dose. Particularly, PAO as an arsenical-based chemotherapeutic agent could not only induce cell apoptosis by generating reactive oxygen species (ROS), but also regulate tumor microenvironments to improve the PDT effect of PCN-224 by mitigating hypoxia and consuming cellular GSH. Both in vitro and in vivo investigations confirmed an effective self-synergy of PAO@PCN@HA in hypoxic tumor therapy with a low systemic toxicity. This integration of microenvironment adjustment with tumor targeted self-synergistic mechanism might provide a new insight for the development of arsenic-based antitumor strategy for clinical applications.

Self-Delivery Photodynamic Nanoinhibitors for Tumor Targeted Therapy and Metastasis Inhibition.

Simultaneous inhibitions of primary tumor growth and distant metastasis are very critical for cancer patients to improve their survival and cure rates. Although photodynamic therapy (PDT) shows great potential for primary tumor treatment, it often exacerbates hypoxia with a reduced therapeutic efficacy and subsequently contributes to carcinoma progression and metastatic dissemination. To solve these issues, self-delivery photodynamic nanoinhibitors (PNI) are developed for tumor targeted therapy and metastasis inhibition. PNI are composed of a carbonic anhydrase inhibitor (CAi), a hydrophilic poly(ethylene glycol) (PEG) linker, and a hydrophobic photosensitizer protoporphyrin IX (PpIX). Such self-delivery design of PNI avoids the premature release and heterogeneous distribution of CAi and PpIX to enhance the availability and synergism. Briefly, the CAi-based nanoinhibitors improve the selectivity of CAi for specific recognition and inhibition of tumor-associated isoform carbonic anhydrase (CA) IX, which would not only facilitate the targeted drug delivery of PNI but also regulate the hypoxia-induced signaling cascade and PDT resistance. Benefiting from the CA IX inhibition and targeted PDT, PNI exhibit a robust inhibitory effect on primary tumor growth and distant metastasis. This targeted self-delivery strategy sheds light on the photosensitizer-based molecular design to overcome the defect of traditional PDT.

Epigenetics-inspired photosensitizer modification for plasma membrane-targeted photodynamic tumor therapy.

In recent years, epigenetics has attracted great attentions in the field of biomedicine, which is used to denote the heritable changes in gene expression without any variation in DNA sequence, including DNA methylation, histone modification and so on. Inspired by it, a simple and versatile amino acids modification strategy is proposed in this paper to regulate the subcellular distribution of photosensitizer for plasma membrane targeted photodynamic therapy (PDT). Particularly, the plasma membrane anchoring ability and photo toxicity of the photosensitizer against different cell lines could be effectively manipulated at a single amino acid level. Systematic researches indicate that the number and variety of amino acids have a significant influence on the plasma membrane targeting effect of the photosensitizer. Furthermore, after self-assembling into nanoparticles, the obtained nano photosensitizers (NPs) also exhibit a good biocompatibility and plasma membrane targeting ability, which are conducive to enhancing the PDT therapeutic effect under light irradiation. Both in vitro and in vivo investigations confirm a robust tumor inhibition effect of NPs with a good biocompatibility. This epigenetics-inspired photosensitizer modification strategy would contribute to the development of structure-based drug design for tumor precision therapy.

Chimeric peptide engineered exosomes for dual-stage light guided plasma membrane and nucleus targeted photodynamic therapy.

Targeted delivery of the drug to its therapeutically active site with low immunogenicity and system toxicity is critical for optimal tumor therapy. In this paper, exosomes as naturally-derived nano-sized membrane vesicles are engineered by chimeric peptide for plasma membrane and nucleus targeted photosensitizer delivery and synergistic photodynamic therapy (PDT). Importantly, a dual-stage light strategy is adopted for precise PDT by selectively and sequentially destroying the plasma membrane and nucleus of tumor cells. Briefly, plasma membrane-targeted PDT of chimeric peptide engineered exosomes (ChiP-Exo) could directly disrupt the membrane integrity and cause cell death to some extent. More interestingly, the photochemical internalization (PCI) and lysosomal escape triggered by the first-stage light significantly improve the cytosolic delivery of ChiP-Exo, which could enhance its nuclear delivery due to the presence of nuclear localization signals (NLS) peptide. Upon the second-stage light irradiation, the intranuclear ChiP-Exo would activate reactive oxygen species (ROS) in situ to disrupt nuclei for robust and synergistic PDT. Based on exosomes, this dual-stage light guided subcellular dual-targeted PDT strategy exhibits a greatly enhanced therapeutic effect on the inhibition of tumor growth with minimized system toxicity, which also provides a new insight for the development of individualized biomedicine for precise tumor therapy.

Ratiometric theranostic nanoprobe for pH imaging-guided photodynamic therapy.

An abnormal pH microenvironment results from the development of tumors, and also affects the therapeutic efficiency of anti-tumor drugs. In this work, a Förster resonance energy transfer (FRET)-based theranostic fluorescent nanoprobe was constructed for simultaneous ratiometric pH sensing and tumor-targeted photodynamic therapy. Based on the FRET process between rhodamine B and protoporphyrin IX (PpIX), the fabricated nanoprobe exhibited excellent pH responsiveness in both solutions and live cells with the ratiometric fluorescence changes. Moreover, this ratiometric pH fluorescent nanoprobe also possessed the capability for pH-responsive singlet oxygen (1O2) generation under light irradiation, guiding robust photodynamic therapy in a pH-dependent manner. Benefiting from the enhanced permeability and retention (EPR) effect, the nanoprobe could significantly inhibit tumor growth and metastasis via targeted photodynamic therapy in vivo. This work presents a novel paradigm for precise tumor theranostics by ratiometric pH fluorescence imaging-guided photodynamic therapy.

A biomimetic cascade nanoreactor for tumor targeted starvation therapy-amplified chemotherapy.

Targeted drug delivery with precisely controlled drug release and activation is highly demanding and challenging for tumor precision therapy. Herein, a biomimetic cascade nanoreactor (designated as Mem@GOx@ZIF-8@BDOX) is constructed for tumor targeted starvation therapy-amplified chemotherapy by assembling tumor cell membrane cloak and glucose oxidase (GOx) onto zeolitic imidazolate framework (ZIF-8) with the loading prodrug of hydrogen peroxide (H2O2)-sensitive BDOX. Biomimetic membrane camouflage affords superior immune evasion and homotypic binding capacities, which significantly enhance the tumor preferential accumulation and uptake for targeted drug delivery. Moreover, GOx-induced glycolysis would cut off glucose supply and metabolism pathways for tumor starvation therapy with the transformation of tumor microenvironments. Importantly, this artificial adjustment could trigger the site-specific BDOX release and activation for cascade amplified tumor chemotherapy regardless of the complexity and variability of tumor physiological environments. Both in vitro and in vivo investigations indicate that the biomimetic cascade nanoreactor could remarkably improve the therapeutic efficacy with minimized side effects through the synergistic starvation therapy and chemotherapy. This biomimetic cascade strategy would contribute to developing intelligent drug delivery systems for tumor precision therapy.

A Theranostic Nanoprobe for Hypoxia Imaging and Photodynamic Tumor Therapy.

Hypoxia is a common feature for most malignant tumors, which was also closely related to the oxygen-dependent photodynamic therapy. Based on Förster resonance energy transfer (FRET), a smart nanoprobe (designated as H-Probe) was designed in this paper for hypoxia imaging and photodynamic tumor therapy. Due to the FRET process, H-Probe could respond to hypoxia with a significant fluorescence recovery. Moreover, abundant in vitro investigations demonstrated that the photosensitizer of PpIX in H-Probe could generate large amounts of singlet oxygen to kill cancer cells in the presence of oxygen and light with appropriate wavelength. Also, intravenously injected H-Probe with light irradiation achieved an effective tumor inhibition in vivo with a reduced side effect. This original strategy of integrating hypoxia imaging and tumor therapy in one nanoplatform would promote the development of theranostic nanoplatform for tumor precision therapy.

Mitochondria and plasma membrane dual-targeted chimeric peptide for single-agent synergistic photodynamic therapy.

Mitochondria and cell membrane play important roles in maintaining cellular activity and stability. Here, a single-agent self-delivery chimeric peptide based nanoparticle (designated as M-ChiP) was developed for mitochondria and plasma membrane dual-targeted photodynamic tumor therapy. Without additional carrier, M-ChiP possessed high drug loading efficacy as well as the excellent ability of producing reactive oxygen species (ROS). Moreover, the dual-targeting property facilitated the effective subcellular localization of photosensitizer protoporphyrin IX (PpIX) to generate ROS in situ for enhanced photodynamic therapy (PDT). Notably, plasma membrane-targeted PDT would enhance the membrane permeability to improve the cellular delivery of M-ChiP, and even directly disrupt the cell membrane to induce cell necrosis. Additionally, mitochondria-targeted PDT would decrease mitochondrial membrane potential and significantly promote the cell apoptosis. Both in vitro and in vivo investigations indicated that this combinatorial PDT in mitochondria and plasma membrane could achieve the therapeutic effect maximization with reduced side effects. The single-agent self-delivery system with dual-targeting strategy was demonstrated to be a promising nanoplatform for synergistic tumor therapy.

A Self-Delivery Chimeric Peptide for Photodynamic Therapy Amplified Immunotherapy.

In this paper, a self-delivery chimeric peptide PpIX-PEG8 -KVPRNQDWL is designed for photodynamic therapy (PDT) amplified immunotherapy against malignant melanoma. After self-assembly into nanoparticles (designated as PPMA), this self-delivery system shows high drug loading rate, good dispersion, and stability as well as an excellent capability in producing reactive oxygen species (ROS). After cellular uptake, the ROS generated under light irradiation could induce the apoptosis and/or necrosis of tumor cells, which would subsequently stimulate the anti-tumor immune response. On the other hand, the melanoma specific antigen (KVPRNQDWL) peptide could also activate the specific cytotoxic T cells for anti-tumor immunity. Compared to immunotherapy alone, the combined photodynamic immunotherapy exhibits significantly enhanced inhibition of melanoma growth. Both in vitro and in vivo investigations confirm that PDT of PPMA has a positive effect on anti-tumor immune response. This self-delivery system demonstrates a great potential of this PDT amplified immunotherapy strategy for advanced or metastatic tumor treatment.

PDCD5 transfection increases cisplatin sensitivity and decreases invasion in hepatic cancer cells.

Low expression levels of the programmed cell death 5 (PDCD5) gene have been reported in numerous human cancers, however, PDCD5 expression has not been investigated in hepatic cancer. The present study aims to investigate the biological behavior of PDCD5 overexpression in hepatocellular carcinoma (HCC) cells. The PDCD5 gene was stably transfected into the HepG2 HCC cell line (HepG2-PDCD5), and the expression levels of PDCD5 were examined by quantitative polymerase chain reaction and western blotting. An MTT assay was used to assess the cellular proliferating ability, and propidium iodide (PI) staining was used to evaluate the cell cycle by flow cytometry. The cells were incubated with 2 ng/ml transforming growth factor (TGF)-ß for 7 days in order to induce invasion and epithelial-mesenchymal transition (EMT). Apoptosis was measured by Annexin V-fluorescein isothiocyanate and PI double labeling. A Boyden chamber invasion assay was carried out to detect tumor invasion. Western blotting was performed to detect the protein expression levels of PDCD5, insulin-like growth factor (IGF)-1 and the EMT marker, Snail. The results showed that the HepG2-PDCD5 cells exhibited slower proliferation rates and high G2/M cell numbers compared with those of the HepG2 and HepG2-Neo controls (P<0.05). The PDCD5 transfected cells showed higher sensitivity to cisplatin treatment than the HepG2-Neo cells, with a higher p53 protein expression level. PDCD5 overexpression can attenuate tumor invasion, EMT and the level of IGF-1 protein induced by TGF-ß treatment. In conclusion, stable transfection of the PDCD5 gene can inhibit growth and induce cell cycle arrest in HepG2 cells, and its also notably improves the apoptosis-inducing effects of cisplatin, and reverses invasion and EMT induced by TGF-ß. The use of PDCD5 is a novel strategy for improving the chemotherapeutic effects on HCC.