Ying-Hsia Shih

Multimodal Image-Guided Photothermal Therapy Mediated by 188Re-Labeled Micelles Containing a Cyanine-Type Photosensitizer

Multifunctional micelles loaded with the near-infrared (NIR) dye and labeled with the radionuclide rhenium-188 ((188)Re) have been developed to provide multimodalities for NIR fluorescence and nuclear imaging and for photothermal therapy (PTT) of cancer. The NIR dye, IR-780 iodide, allowed the micelles to have dual functions in cancer NIR imaging and PTT. The (188)Re-labeled IR-780 micelles enabled imaging by NIR fluorescence and by microSPECT to guide the delivery of drugs and to monitor in real-time the tumor accumulation, intratumoral distribution, and kinetics of drug release, which serve as a basis of specific photothermal injury to the targeted tissue. We also investigated the biodistribution, generation of heat, and photothermal cancer ablation of IR-780 micelles of both in vitro and in vivo xenografts. Histopathology observed irreversible tissue damage, such as necrotic features, decreased cell proliferation, increased apoptosis of cells, and increased expression of heat shock proteins in the PTT-treated tumors. The (188)Re-labeled IR-780 micelles offer multifunctional modalities for NIR fluorescence and nuclear imaging and for PTT of cancer.

Development of in Situ Forming Thermosensitive Hydrogel for Radiotherapy Combined with Chemotherapy in a Mouse Model of Hepatocellular Carcinoma

This study evaluated a system for local cancer radiotherapy combined with chemotherapy. The delivery system is a thermosensitive hydrogel containing a therapeutic radionuclide ((188)Re-Tin colloid) and a chemotherapeutic drug (liposomal doxorubicin). The thermosensitive PCL-PEG-PCL copolymer was designed to spontaneously undergo a sol-gel phase transition in response to temperature, remaining liquid at room temperature and rapidly forming a gel at body temperature. A scanning electron microscope was used to observe the microstructure of the fully loaded hydrogel. Release of radionuclide and doxorubicin from the hydrogel was slow, and the system tended to remain stable for at least 10 days. After the intratumoral administration of Lipo-Dox/(188)Re-Tin hydrogel in mice with hepatocellular carcinoma (HCC), its retention by the tumor, spatiotemporal distribution, and therapeutic effect were evaluated. The residence time in the tumor was significantly longer for (188)Re-Tin loaded hydrogel than for Na (188)Re perrhenate (Na (188)ReO4). The hydrogel after thermal transition kept the radionuclide inside the tumor, whereas free (188)Re perrhenate ((188)ReO4) diffused quickly from the tumor. The tumor growth was more profoundly inhibited by treatment with Lipo-Dox/(188)Re-Tin hydrogel (with up to 80% regression of well-established tumors on day 32) than treatment with either (188)Re-Tin hydrogel or Lipo-Dox hydrogel. Therefore, this injectable and biodegradable hydrogel may offer the advantage of focusing radiotherapy and chemotherapy locally to maximize their effects on hepatocellular carcinoma.

EGFR-targeted micelles containing near-infrared dye for enhanced photothermal therapy in colorectal cancer

ABSTRACT The purpose of this research was to investigate the effectiveness of epidermal growth factor receptor (EGFR) targeted micelles loaded with IR‐780 (Cetuximab/IR‐780/micelles) for generating tumor targeting, multimodal images, and photothermal therapy (PTT). We initially studied the cellular uptake of these micelles using the HCT‐116 and SW‐620 cell lines. HCT‐116 (high expression of EGFR) and SW‐620 (low expression of EGFR) cell lines were used to examine biodistribution and antitumor effects of Cetuximab/IR‐780/micelles. Time‐lapse near‐IR fluorescence (NIRF) images also indicated the highest IR‐780 accumulation from Cetuximab/IR‐780/micelles in HCT‐116 tumors (p < 0.05). HCT‐116 tumors in tumor‐bearing mice exhibited significantly higher accumulations of Cetuximab/IR‐780/111In‐micelles than SW‐620 tumors in Micro‐SPECT/CT imaging and biodistribution studies (p < 0.05). Dual‐radioisotope Nano‐SPECT/CT imaging of Cetuximab/131I‐IR‐780/111In‐micelles demonstrated simultaneous high accumulation of both IR‐780 and micelles in HCT‐116 tumors, but not in SW‐620 tumors. Regarding antitumor effects, following the Cetuximab/IR‐780/micelles with PPT on day 6, all HCT‐116 tumor‐bearing mice were cured. In contrast, SW‐620 tumors relapsed at 13 days after treatment. In summary, we expect that the Cetuximab/IR‐780/micelles could enhance the antitumor effects by PTT in EGFR overexpression colorectal cancers through effective drug delivery nanoparticles.

Targeting Colorectal Cancer Stem-Like Cells with Anti-CD133 Antibody-Conjugated SN-38 Nanoparticles

Cancer stem-like cells play a key role in tumor development, and these cells are relevant to the failure of conventional chemotherapy. To achieve favorable therapy for colorectal cancer, PEG-PCL-based nanoparticles, which possess good biological compatibility, were fabricated as nanocarriers for the topoisomerase inhibitor, SN-38. For cancer stem cell therapy, CD133 (prominin-1) is a theoretical cancer stem-like cell (CSLC) marker for colorectal cancer and is a proposed therapeutic target. Cells with CD133 overexpression have demonstrated enhanced tumor-initiating ability and tumor relapse probability. To resolve the problem of chemotherapy failure, SN-38-loaded nanoparticles were conjugated with anti-CD133 antibody to target CD133-positive (CD133(+)) cells. In this study, anti-CD133 antibody-conjugated SN-38-loaded nanoparticles (CD133Ab-NPs-SN-38) efficiently bound to HCT116 cells, which overexpress CD133 glycoprotein. The cytotoxic effect of CD133Ab-NPs-SN-38 was greater than that of nontargeted nanoparticles (NPs-SN-38) in HCT116 cells. Furthermore, CD133Ab-NPs-SN-38 could target CD133(+) cells and inhibit colony formation compared with NPs-SN-38. In vivo studies in an HCT116 xenograft model revealed that CD133Ab-NPs-SN-38 suppressed tumor growth and retarded recurrence. A reduction in CD133 expression in HCT116 cells treated with CD133Ab-NPs-SN-38 was also observed in immunohistochemistry results. Therefore, this CD133-targeting nanoparticle delivery system could eliminate CD133-positive cells and is a potential cancer stem cell targeted therapy.

Traceable Self‐Assembly of Laser‐Triggered Cyanine‐Based Micelle for Synergistic Therapeutic Effect

To track nanocarriers, many researches adopt nanocarriers labeled with radiotracers or encapsulating near-infrared fluorescence (NIRF) dye. In this study, novel amphiphilic copolymers, methoxy poly(ethylene glycol) (mPEG)-cyanine-poly(ε-caprolactone) (PCL) (mPEG-Cy-PCL) are synthesized. mPEG-Cy-PCL are capable of performing NIRF imaging, photothermal therapy (PTT) on cancer cells and self-assembly nanocarriers. Cy-based micelles can encapsulate doxorubicin (Doxo@Cy-micelle) and achieve NIRF image-guided drug delivery. Doxo@Cy-micelles are nanosized micelles enhancing the accumulation of Doxo in tumor sites and decreasing side effects. Doxo@Cy-micelles exhibit an excellent PTT and synergistic chemotherapy of cancer via laser-triggered release of Doxo from micelles, eventually resulting in decreased cancer recurrence rates. The results show that Cy-based micelles are excellent nanocarriers for NIRF imaging and synergistic photothermal-chemotherapy of cancer.

Therapeutic and scintigraphic applications of polymeric micelles: combination of chemotherapy and radiotherapy in hepatocellular carcinoma

This study evaluated a multifunctional micelle simultaneously loaded with doxorubicin (Dox) and labeled with radionuclide rhenium-188 (188Re) as a combined radiotherapy and chemotherapy treatment for hepatocellular carcinoma. We investigated the single photon emission computed tomography, biodistribution, antitumor efficacy, and pathology of 188Re-Dox micelles in a murine orthotopic luciferase-transfected BNL tumor cells hepatocellular carcinoma model. The single photon emission computed tomography and computed tomography images showed high radioactivity in the liver and tumor, which was in agreement with the biodistribution measured by γ-counting. In vivo bioluminescence images showed the smallest size tumor (P<0.05) in mice treated with the combined micelles throughout the experimental period. In addition, the combined 188Re-Dox micelles group had significantly longer survival compared with the control, 188ReO4 alone (P<0.005), and Dox micelles alone (P<0.01) groups. Pathohistological analysis revealed that tumors treated with 188Re-Dox micelles had more necrotic features and decreased cell proliferation. Therefore, 188Re-Dox micelles may enable combined radiotherapy and chemotherapy to maximize the effectiveness of treatment for hepatocellular carcinoma.

Anti-angiogenic treatment (Bevacizumab) improves the responsiveness of photodynamic therapy in colorectal cancer

Photodynamic therapy (PDT) is a treatment utilizing the combined action of photosensitizers and light for the treatment of various cancers. The mechanisms for tumor destruction after PDT include direct tumor cell kill by singlet oxygen species (OS), indirect cell kill via vascular damage, and an elicited immune response. However, it has been reported that many cellular activators, including vascular endothelial growth factor (VEGF), are produced by tumor cells after PDT. In this study, we demonstrate that meta-tetra(hydroxyphenyl) chlorin (mTHPC)-based photodynamic therapy combined with bevacizumab (Avastin™), an anti-VEGF neutralizing monoclonal antibody that blocks the binding of VEGF to its receptor, can enhance the effectiveness of each treatment modality. We evaluated the efficacy of bevacizumab-based anti-angiogenesis in combination with PDT as well as the resulting VEGF levels and microvessel density (MVD) in a mouse model of human colon cancer. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) were performed to assess VEGF concentrations and microvessel density in the various treatment groups, and confocal imaging and high performance liquid chromatography (HPLC) analyses were used to measure the distribution and concentration of mTHPC in tumors. Our results demonstrate that combination of PDT followed by bevacizumab significantly elicits a greater tumor response whereas bevacizumab treatment prior to PDT led to a reduced tumor response. Immunostaining and ELISA analyses revealed a lower expression of VEGF in tumors treated with combination therapy of PDT followed by bevacizumab. However, bevacizumab treatment decreased the accumulation of mTHPC in tumors 24 h after administration, which complemented the results of decreased anti-tumor efficacy of bevacizumab followed by PDT.

pH-Responsive Nanophotosensitizer for an Enhanced Photodynamic Therapy of Colorectal Cancer Overexpressing EGFR

Photodynamic therapy (PDT) has been shown to kill cancer cells and improve survival and quality of life in cancer patients, and numerous new approaches have been considered for maximizing the efficacy of PDT. In this study, a new multifunctional nanophotosensitizer Ce6/GE11-(pH)micelle was developed to target epidermal growth factor receptor (EGFR) overexpressing colorectal cancer (CRC) cells. This nanophotosensitizer was synthesized using a micelle comprising pH-responsive copolymers (PEGMA-PDPA), biodegradable copolymers (mPEG-PCL), and maleimide-modified biodegradable copolymers (Mal-PEG-PCL) to entrap the potential hydrophobic photosensitizer chlorin e6 (Ce6) and to present EGFR-targeting peptides (GE11) on its surface. In the presence of Ce6/GE11-(pH)micelles, Ce6 uptake by EGFR-overexpressing CRC cells significantly increased due to GE11 specificity. Moreover, Ce6 was released from Ce6/GE11-(pH)micelles in tumor environments, leading to improved elimination of cancer cells in PDT. These results indicate enhanced efficacy of PDT using Ce6/GE11-(pH)micelle, which is a powerful nanophotosensitizer with high potential for application to future PDT for CRC.

EGFR-targeting Peptide Conjugated pH-sensitive Micelles as a Potential Drug Carrier for Photodynamic Detection and Therapy of Cancer

Multifunctional theranostics have recently been intensively explored to optimize the efficacy and safety. Herein, we report multifunctional micelle that constructed from graft copolymer PEGMA-co-PDPA and diblock copolymer mPEG-b-PCL as the carrier of hydrophobic photosensitizer, chlorin e6 (Ce6) for simultaneous fluorescence imaging and photodynamic therapy. The functional inner core of PEGMA-co-PDPA exhibited pH stimulate to accelerate drug release under slightly acidic microenvironments of tumors and the outer shell of micelles with epidermal growth factor receptor (EGFR)-targeting GE11 peptides for active targeting of EGFR-overexpressing cancer cells. The results demonstrate that GE11-conjugated chlorin e6-loaded micelles (GE11-Ce6-micelles) with particle size around 100 nm and the micelles had well defined core shell structure which was evaluated by TEM. In the in vitro cellular uptake studies, GE11-Ce6-micelles exhibited a higher amount of intracellular uptake of chlorin e6 in HCT116 cancer cells (EGFR high expression) via receptor-mediated endocytosis, in contrast with the time-dependent passive uptake of the non-targeted Ce6-micelles, thereby providing a effective photocytotoxic effect on the HCT116 cancer cells. In vivo study revealed that GE11-Ce6-micelles exhibited tumor targeting for photodynamic detection and excellent inhibition on tumor growth after irradiation, indicating that GE11-Ce6-micelles could be successfully applied to the effective fluorescence imaging and photodynamic therapy of cancer.