Yuxiang Ma

In vivo targeted deep-tissue photodynamic therapy based on near-infrared light triggered upconversion nanoconstruct.

Two major challenges of current photodynamic therapy (PDT) are the limited tissue penetration of excitation light and poor tumor-selectivity of the photosensitizer (PS). To address these issues, we developed a multifunctional nanoconstruct consisting of upconversion nanoparticles (UCNPs) that transform near-infrared (NIR) light to visible light and a photosensitizer zinc(II) phthalocyanine (ZnPc). Folate-modified amphiphilic chitosan (FASOC) was coated on the surface of UCNPs to anchor the ZnPc close to the UCNPs, thereby facilitating resonance energy transfer from UCNPs to ZnPc. Confocal microscopy and NIR small animal imaging demonstrated the enhanced tumor-selectivity of the nanoconstructs to cancer cells that overexpressed folate receptor. Reactive oxygen species (ROS) generation in cancer cells under a 1-cm tissue was higher upon excitation of UCNPs with the 980 nm light than that with 660 nm irradiation. In vivo PDT treatments for deep-seated tumors demonstrated that NIR light-triggered PDT based on the nanoconstructs possessed remarkable therapeutic efficacy with tumor inhibition ratio up to 50% compared with conventional visible light-activated PDT with a noticeable reduced tumor inhibition ratio of 18%. These results indicate that the multifunctional nanoconstruct is a promising PDT agent for deep-seated tumor treatment and demonstrate a new paradigm for enhancing PDT efficacy.

Multifunctional Gold Nanostar Conjugates for Tumor Imaging and Combined Photothermal and Chemo-therapy

Uniform gold nanostars (Au NS) were conjugated with cyclic RGD (cRGD) and near infrared (NIR) fluorescence probe (MPA) or anti-cancer drug (DOX) to obtain multi-functional nanoconstructs, Au-cRGD-MPA and Au-cRGD-DOX respectively. The NIR contrast agent Au-cRGD-MPA was shown to have low cytotoxicity. Using tumor cells and tumor bearing mice, these imaging nanoparticles demonstrated favorable tumor-targeting capability mediated by RGD peptide binding to its over-expressed receptor on the tumor cells. The multi-therapeutic analogue, Au-cRGD-DOX, integrates targeting tumor, chemotherapy and photo-thermotherapy into a single system. The synergistic effect of photo-thermal therapy and chemotherapy was demonstrated in different tumor cell lines and in vivo using S180 tumor-bearing mouse models. The viability of MDA-MB-231 cells was only 40 % after incubation with Au-cRGD-DOX and irradiation with NIR light. Both tail vein and intratumoral injections showed Au-cRGD-DOX treated mice exhibiting the slowest tumor increase. These results indicate that the multifunctional nanoconstruct is a promising combined therapeutic agent for tumor-targeting treatment, with the potential to enhance the anti-cancer treatment outcomes.

Multifunctional near-infrared-emitting nano-conjugates based on gold clusters for tumor imaging and therapy

Gold nanoclusters (NCs) were functionalized as a fluorescent probe and a pro-drug intended for tumor diagnosis and therapy. Firstly, Au NCs were conjugated with methionine (Met) and MPA, a near-infrared (NIR) fluorescent dye, giving a probe, Au-Met-MPA. The tumor targeting capability endowed by Met as well as low cytotoxicity of this contrast agent and its clinical potential for tumor targeting imaging were demonstrated in vitro and in vivo. Secondly, Doxorubicin (DOX), a widely used clinical anti-cancer drug, was immobilized on the methionine modified Au NCs to form a pro-drug, Au-Met-DOX. The enhanced tumor affinity and improved anti-tumor activity of this pro-drug were demonstrated. Results in this study suggest not only the prospect of non-toxic Au NCs modified with functional ligands for tumor-targeted imaging, but also confirm the promising future of Au NCs as a core for the design of pro-drug in the field of cancer therapy.

Drug loaded multilayered gold nanorods for combined photothermal and chemotherapy

In this study, gold nanorods (AuNRs) were first stabilized by hexadecyltrimethylammonium bromide (CTAB) and then coated with two kinds of polyelectrolytes (PE) and BSA to obtain multi-layered AuNRs (AuNRs-PE-BSA). Furthermore, the anti-cancer drug doxorubicin (DOX) was encapsulated into AuNRs-PE-BSA by the electrostatic force and the nanocomposites formed were named AuNRs/DOX-PE-BSA. The success of coating was verified by transmission electron microscopy (TEM), zeta potential, gel-electrophoresis and thermogravimetric analysis (TGA). The MTT assay indicated that the cytotoxicity of AuNRs decreased dramatically after multi-layer capping. The time-dependent nucleus-targeting capability of AuNRs/DOX-PE-BSA was confirmed in cell affinity evaluations. The in vitro and in vivo experiments demonstrated that AuNRs/DOX-PE-BSA, which combined photothermal and chemotherapy for tumor therapy, bears a markedly improved curative effect and holds promising prospects in the field of nanomedicine.

Estrogen receptor β potentiates the antiproliferative effect of raloxifene and affects the cell migration and invasion in HCT-116 colon cancer cells

BackgroundEstrogen receptor β (ERβ) is the predominant ER in the colorectal epithelium, whose expression is greatly reduced in colorectal cancer compared with normal colon tissue. Recent in vitro studies suggested that ERβ may suppress tumor growth. No research was reported whether ERβ can be used as therapeutic agent for colon cancer.MethodsIn this study, ERβ gene constructed into adenoviral (Ad) vectors was used to treat colon cancer HCT-116 cells alone or in combination with raloxifene. In vitro and in vivo studies were conducted to investigate the therapeutic effects of ERβ and raloxifene in HCT-116 cells.ResultsOur results indicated that, although Ad-ERβ alone had no effect on the proliferation of HCT-116 cells, the combination of Ad-ERβ with raloxifene significantly inhibited the proliferation of HCT-116 cells. The apparently apoptotic induction effects may partly explain the cytotoxicity of the two agents. The results of the study of ERβ on migration and invasion of HCT-116 cells demonstrated that overexpression of ERβ significantly decreased cell migration and increased invasion of cells. The antitumor efficacies of ERβ as well as raloxifene were further investigated on HCT-116 tumor bearing mice. Results demonstrated that both Ad-ERβ and raloxifene individually inhibited tumor growth. The combination group showed the highest inhibitory efficiency compared with other three groups.ConclusionThese findings demonstrated that combined administration of Ad-ERβ with raloxifene represents a promising colon cancer therapeutic strategy.

Small sized EGFR1 and HER2 specific bifunctional antibody for targeted cancer therapy.

Targeting tumors using miniature antibodies is a novel and attractive therapeutic approach, as these biomolecules exhibit low immunogenicity, rapid clearance, and high targeting specificity. However, most of the small-sized antibodies in existence do not exhibit marked anti-tumor effects, which limit their use in targeted cancer immunotherapy. To overcome this difficulty in targeting multiple biomarkers by combination therapies, we designed a new bifunctional antibody, named MaAbNA (multivalent antibody comprised of nanobody and affibody moieties), capable of targeting EGFR1 and HER2, which are widely overexpressed in a variety of tumor types. The small-sized (29 kDa) MaAbNA, which was expressed in E.coli, consists of one anti-EGFR1 nanobody and two anti-HER2 affibodies, and possesses high affinity (KD) for EGFR1 (~4.1 nM) and HER2 (~4.7 nM). In order to enhance its anti-tumor activity, MaAbNA was conjugated with adriamycin (ADM) using a PEG2000 linker, forming a new complex anticancer drug, MaAbNA-PEG2000-ADM. MaAbNA exhibited high inhibitory effects on tumor cells over-expressing both EGFR1 and HER2, but displayed minimal cytotoxicity in cells expressing low levels of EGFR1 and HER2. Moreover, MaAbNA-PEG2000-ADM displayed increased tumoricidal effects than ADM or MaAbNA alone, as well exhibited greater antitumor efficacy than EGFR1 (Cetuximab) and HER2 (Herceptin) antibody drugs. The ability of MaAbNA to regulate expression of downstream oncogenes c-jun, c-fos, c-myc, as well as AEG-1 for therapeutic potential was evaluated by qPCR and western-blot analyses. The antitumor efficacy of MaAbNA and its derivative MaAbNA-PEG2000-ADM were validated in vivo, highlighting the potential for use of MaAbNA as a highly tumor-specific dual molecular imaging probe and targeted cancer therapeutic.

MUC1 aptamer-based near-infrared fluorescence probes for tumor imaging.

PurposeDNA aptamer (APT) is able to bind to Mucin 1 (MUC1) specifically. The possibility of APT acting as a moiety to construct tumor-targeting probes was investigated.ProceduresA near-infrared (NIR) fluorescent dye (MPA) and polyethylene glycol (PEG) were conjugated to APT to form APT-MPA and APT-PEG-MPA. The successful synthesis of the two probes was characterized via thin layer chromatography (TLC) and optical spectra. The tumor-targeting efficacy of the probes was evaluated in detail at cell level and animal level, respectively.ResultsThe results indicated that MPA and PEG were successfully coupled with APT. APT-based probes were mediated by Mucin 1 into tumor cells, and PEG-modified probe exhibited higher cell affinity.ConclusionsThe aptamer-based NIR fluorescent probes are promising candidates for tumor imaging and diagnosis.

The enhanced antiproliferative response to combined treatment of trichostatin A with raloxifene in MCF-7 breast cancer cells and its relevance to estrogen receptor β expression

Antiestrogen is one type of the endocrine therapeutic agents for estrogen receptor α (ERα)-positive breast cancer. Unfortunately, this treatment alone is insufficient. Here we reported a novel potential anticancer strategy by using histone deacetylase (HDAC) inhibitor to enhance the action of endocrine therapy in ERα-positive breast cancer cell. The well-described HDAC inhibitor, trichostatin A (TSA), and antiestrogen raloxifene were found to, respectively, inhibit E2-induced proliferation of MCF-7 breast cancer cell in a dose-responsive and time-dependent manner. TSA and raloxifene enhanced the antiproliferative activity of each other by promoting cell death via apoptosis and cell cycle arrest. Thus, they displayed better antiproliferative effects in combined treatment than that with either agent alone. The expression level of estrogen receptor β (ERβ) showed a marked increase after TSA or/and raloxifene treatment. Treatments with TSA or/and raloxifene resulting in the up-regulation of ERβ are in accordance with the antiproliferative effects of the two agents. Furthermore, the over-expression of ERβ by adenovirus delivery could inhibit the proliferation of MCF-7 tumor cells and drastically enhanced the antiproliferative effects of TSA and raloxifene. These results demonstrated that the interference of ERβ on the antiproliferative effects of HDAC inhibitor and antiestrogen constitutes a promising approach for breast cancer treatment.

Therapeutic effect of the treatment for colorectal cancer with adenoviral vectors mediated estrogen receptor β gene therapy combined with thermotherapy

IntroductionOur preliminary study on repressing colorectal tumors by recombinant adenoviruses (Ads) delivering the human ERβ gene (Ad-ERβ) has achieved positive result.MethodsIn this study, hydrophobic fluorescent dyes ICG-Der-01 was entrapped into the N-succinyl-N′-octyl chitosan (SOC) micelles to form the near infrared absorbing dyes SOC-ICG-Der-01 and SOC-ICG-Der-01 mediated near infrared laser (SOC-ICG-Der-01/NIR) thermotherapy was combined with Ad-ERβ gene therapy to regress colon cancer in vivo.ResultsFirstly, the antitumor efficacies of SOC-ICG-Der-01/NIR thermotherapy were investigated on S180 ascites tumor-bearing mice. Results indicated that, the average tumor volume of SOC-ICG-Der-01/NIR group was the smallest among the three treatment groups. Then, thermotherapy with SOC-ICG-Der-01/NIR combined with Ad-ERβ gene therapy to treat HCT-116 colon cancer xenograft model was investigated. Further results demonstrated that, SOC-ICG-Der-01/NIR thermotherapy showed the significantly inhibitory efficiency compared with control group and Ad-ERβ enhanced the therapeutic effect of SOC-ICG-Der-01/NIR.ConclusionThese findings demonstrated that combined administration of Ad-ERβ with SOC-ICG-Der-01/NIR thermotherapy represents a promising colon cancer therapeutic strategy.

Dual fluorescence nano-conjugates based on gold nanoclusters for tumor-targeting imaging

The unique properties of gold nanoclusters (Au NCs) enable them to be functionalized as fluorescent probes or pro-drugs for biomedical application. A facile approach was introduced to synthesize nanoconjugates (Au–cRGD–MPA), which was composed of Au NCs, cyclic (Arg–Gly–Asp–DTyr–Lys) (cRGD) peptide and a near infrared (NIR) fluorescence dye (MPA). The nanoconjugates exhibited dual fluorescence in the visible range and NIR range simultaneously. The low cytotoxicity of Au–cRGD–MPA was demonstrated in MCF-7 cell line and U87 cell line. The cell affinity investigations verified the outstanding tumor-targeting capability of Au–cRGD–MPA for tumor cells. The biodistribution characteristics and tumor targeting ability of the probes were elucidated in normal nude mice and tumor-bearing mice, respectively. Attributing to the small size (less than 5 nm), the majority of the nanoconjugates metabolized from the living subjects via the kidney-bladder pathway. Additionally, Au–cRGD–MPA displayed favorable tumor-specificity in Integrin αvβ3 over-expressed tumor-bearing (MDA-MB-231) mice. Consequently, the results demonstrated that the dual fluorescence probe is a promising candidate for tumor imaging and disease treatment monitoring.