Seol Hwa Shin

Multifunctional hollow gold nanoparticles designed for triple combination therapy and CT imaging.

Hollow gold nanoparticles (HGNP) are a novel class of hybrid metal nanoparticles whose unique optical and morphological properties have spawned new applications including more effective cancer therapy. The shell thickness of HGNPs can tune the surface plasmon resonance to the near infrared light, resulting in photothermal ablation of tumors with optimal light penetration in tissue. The hollow cavity within a HGNP is able to accommodate a high payload of chemotherapeutic agents. They have also been used for enhancing radiosensitization in tumors during radiotherapy due to the high X-ray absorption capability of gold particles. However, no report has yet been published that utilize HGNPs for the triple combination therapy and CT imaging. In this study, we synthesized HGNPs which exhibit better response to radiation for therapy and imaging and demonstrated the effects of combined chemotherapy, thermal and radiotherapy. This combination strategy presented delayed tumor growth by 4.3-fold and reduced tumors weight by 6.8-fold compared to control tumors. In addition, we demonstrated the feasibility of HGNP as a CT imaging agent. It is expected that translating these capabilities to human cancer patients could dramatically increase the antitumor effect and potentially overcome resistance to chemotherapeutic agents and radiation.

Virosomes of hepatitis B virus envelope L proteins containing doxorubicin: synergistic enhancement of human liver-specific antitumor growth activity by radiotherapy

Bionanocapsules (BNCs) are hollow nanoparticles consisting of hepatitis B virus (HBV) envelope L proteins and have been shown to deliver drugs and genes specifically to human hepatic tissues by utilizing HBV-derived infection machinery. The complex of BNCs with liposomes (LPs), the BNC–LP complexes (a LP surrounded by BNCs in a rugged spherical form), could also become active targeting nanocarriers by the BNC function. In this study, under acidic conditions and high temperature, BNCs were found to fully fuse with LPs (smooth-surfaced spherical form), deploying L proteins with a membrane topology similar to that of BNCs (ie, virosomes displaying L proteins). Doxorubicin (DOX) was efficiently encapsulated via the remote loading method at 14.2%±1.0% of total lipid weight (mean ± SD, n=3), with a capsule size of 118.2±4.7 nm and a ζ-potential of −51.1±1.0 mV (mean ± SD, n=5). When mammalian cells were exposed to the virosomes, the virosomes showed strong cytotoxicity in human hepatic cells (target cells of BNCs), but not in human colon cancer cells (nontarget cells of BNCs), whereas LPs containing DOX and DOXOVES (structurally stabilized PEGylated LPs containing DOX) did not show strong cytotoxicity in either cell type. Furthermore, the virosomes preferentially delivered DOX to the nuclei of human hepatic cells. Xenograft mice harboring either target or nontarget cell-derived tumors were injected twice intravenously with the virosomes containing DOX at a low dose (2.3 mg/kg as DOX, 5 days interval). The growth of target cell-derived tumors was retarded effectively and specifically. Next, the combination of high dose (10.0 mg/kg as DOX, once) with tumor-specific radiotherapy (3 Gy, once after 2 hours) exhibited the most effective antitumor growth activity in mice harboring target cell-derived tumors. These results demonstrated that the HBV-based virosomes containing DOX could be an effective antitumor nanomedicine specific to human hepatic tissues, especially in combination with radiotherapy.

Ibulocydine sensitizes human cancers to radiotherapy by induction of mitochondria-mediated apoptosis.

BACKGROUND AND PURPOSE Ibulocydine (IB), a novel prodrug of CDK inhibitor, has been reported to have anti-cancer effect in human hepatoma cells. In order to address its feasibility as a radiosensitizer to improve radiotherapeutic efficacy for human cancers, this study was designed. MATERIAL AND METHODS Human cancer cells of lung and colon were treated with IB and/or radiotherapy (RT). The cellular effects were assessed by CCK-8, clonogenic, flow cytometric, and western blotting assays. In vivo radiotherapeutic efficacy was evaluated using the xenograft mouse model. RESULTS Combined treatment of IB and RT significantly reduced viability and survival fraction of the cells. Apoptotic cell death accompanied with activation of caspases, decrease in Bcl-2/Bax expression, loss of mitochondrial membrane potential (MMP) leading to release of cytochrome c into cytosol was observed. Recovery of Bcl-2 expression level by introducing Bcl-2 expressing plasmid DNA compromised the loss of MMP and apoptosis induced by IB and RT. In vivo therapeutic efficacy of combined treatment was verified in the xenograft mouse model, in which tumor growth was markedly delayed by RT with IB. CONCLUSIONS IB demonstrated the property of sensitizing human cancer cells to RT by induction of mitochondria-mediated apoptosis, suggesting that IB deserves to be applied for chemoradiotherapy.

Ibulocydine sensitizes human hepatocellular carcinoma cells to TRAIL-induced apoptosis via calpain-mediated Bax cleavage

Tumor necrosis factor-related apoptosis-induced ligand (TRAIL) induces apoptosis selectively in cancer cells without affecting the majority of normal human cells. However, hepatocellular carcinoma (HCC) cells often display resistance to TRAIL-induced apoptosis. Ibulocydine (IB) is an isobutyrate ester pro-drug of a novel synthetic Cdk inhibitor that targets Cdk7 and Cdk9. In this study, we show that treatment with subtoxic doses of IB in combination with TRAIL displays potent cytotoxicity in TRAIL-resistant human HCC cells. Combination of IB and TRAIL was found to synergistically induce apoptosis through activation of caspases, which was blocked by a pan-caspase inhibitor (zVAD). Although the expression of Mcl-1 and survivin were reduced by IB plus TRAIL, overexpression of Mcl-1 and survivin did not block the cell death induced by co-treatment. Moreover, overexpression of Bcl-xL did not significantly interfere with the cell death induced by co-treatment of IB and TRAIL. Interestingly, the combination treatment induced cleavage of Bax, which was translocated to mitochondria upon induction of apoptosis. Furthermore, down-regulation of Bax by small interfering RNA effectively reduced the cell death and loss of mitochondrial membrane potential (MMP) caused by co-treatment with IB and TRAIL. Finally, pre-treatment of HCC cells with a calpain inhibitor effectively blocked IB plus TRAIL-induced cleavage of Bax and apoptosis. Collectively, our results demonstrate that IB increases the sensitivity of human HCC cells to TRAIL via mitochondria signaling pathway mediated by calpain-induced cleavage of Bax, suggesting that combined treatment with IB and TRAIL may offer an effective therapeutic strategy for human HCC.

A cisplatin‑incorporated liposome that targets the epidermal growth factor receptor enhances radiotherapeutic efficacy without nephrotoxicity

Radiotherapy (RT) is one of the major modalities for non‑small cell lung cancer (NSCLC), but its efficacy is often compromised by cellular resistance caused by various mechanisms including the overexpression of epidermal growth factor receptor (EGFR). Although cis‑diamminedichloroplatinum(Ⅱ) (cisplatin, CDDP) has been well characterized as an effective radiosensitizer, its clinical application is limited by its severe nephrotoxic effects. In our current study, we developed a CDDP‑incorporated liposome (LP) conjugated with EGFR antibodies (EGFR:LP‑CDDP) and evaluated its potential to radiosensitize EGFR‑overexpressing cells without exerting nephrotoxic effects. EGFR:LP‑CDDP showed higher cytotoxicity than non‑targeting liposomal CDDP (LP‑CDDP) in the cells expressing EGFR in vitro. In an A549 cell‑derived xenograft tumor mouse model, increased delays in tumor growth were observed in the mice treated with a combination of EGFR:LP‑CDDP and radiation. Notably, the EGFR:LP‑CDDP‑treated animals showed no differences in body weight loss, survival rates of nephrotoxicity compared with untreated control mice. In contrast, the use of CDDP caused lower body weights and poorer survival outcomes accompanied by a significant level of nephrotoxicity [e.g., decreased kidney weight, increased blood urea nitrogen (BUN) and creatinine, and pathological change]. These findings suggest the feasibility of using EGFR:LP‑CDDP to radiosensitize cells in a targeted manner without inducing nephrotoxic effects. This compound may therefore have clinical potential as part of a tailored chemoradiotherapy strategy.

Docetaxel-polymeric nanoparticle enhances radiotherapeutic efficacy in human pancreatic cancer

Background: Nanoparticle therapeutics is promising platform for cancer treatment. In our previous study, we have developed polymeric nanoparticles (PNP) in which docetaxel was incorporated to reduce the side effects and improve the therapeutic efficacy, and recently finished its phase 1 clinical study in patients with solid tumors. Methods: Radiotherapeutic efficacy of the docetaxel-contained PNP (DTX-PNP) in pancreatic cancer cells was determined by both in vitro and in vivo assay such as clonogenic survival assay with cancer cell lines, western blot for apoptotic cell death and tumor growth inhibition assay using several kinds of xenograft models. The tumors derived from human pancreatic cancer AsPC-1 or BxPC-3 cells were analyzed by immunohistochemistry (IHC) to detect in apoptosis and tubulin polymerization induced by DTX-PNP. The combinational therapeutic effect of DTX-PNP and ionizing radiation (IR) was evaluated in vivo mice models of AsPC-1 or BxPC-3 cell line-derived xenograft models and patient-derived xenograft model, and compared to that of reference drugs. Results: DTX-PNP in combination with IR showed high cytotoxicity to pancreatic cancer cells, and ultimate inhibition of cell proliferation as determined via in vitro assays. In vivo radiotherapeutic efficacy was markedly enhanced by intravenous injection of DTX-PNP comparing to Gemzar, a common chemoradiation therapeutic agent in pancreatic cancer. Conclusions: These results suggested DTX-PNP can hold an invaluable and promising position in treating human pancreatic cancer as a novel and effective radiosensitizing agent.

A Disposable and Multi-Chamber Film-Based PCR Chip for Detection of Foodborne Pathogen

Since the increment of the threat to public health caused by foodborne pathogens, researches have been widely studied on developing the miniaturized detection system for the on-site pathogen detection. In the study, we focused on the development of portable, robust, and disposable film-based polymerase chain reaction (PCR) chip containing a multiplex chamber for simultaneous gene amplification. In order to simply fabricate and operate a film-based PCR chip, different kinds of PCR chambers were designed and fabricated using polyethylene terephthalate (PET) and polyvinyl chloride (PVC) adhesive film, in comparison with commercial PCR, which employs a stereotyped system at a bench-top scale. No reagent leakage was confirmed during the PCR thermal cycling using the film PCR chip, which indicates that the film PCR chip is structurally stable for rapid heat cycling for DNA amplification. Owing to use of the thin film to fabricate the PCR chip, we are able to realize fast thermal transfer from the heat block that leads to short PCR amplification time. Moreover, using the film PCR chip, we could even amplify the target pathogen with 10 CFU mL−1. The artificially infected milk with various concentration of Bacillus cereus was successfully amplified on a single film PCR chip. On the basis of the reliable results, the developed film PCR chip could be a useful tool as a POCT device to detect foodborne pathogens via genetic analysis.