Generation of the human pluripotent stem cell lines KUMi005-A from a patients with multiple myeloma.

Multiple myeloma (MM) progresses with abnormal monoclonal proliferation and accumulation of malignant plasma cells in the bone marrow. We established human induced pluripotent stem cells (iPSCs), KUMi005-A, from bone marrow samples of a patient with MM. This reprogrammed cell line has similar characteristics to human embryonic stem cells, such as proliferation properties and pluripotency. KUMi005-A iPSCs may be applicable in MM disease modeling and cell-based therapies.

Generation of a human induced pluripotent stem cell line KUMi006 from a patient with multiple myeloma.

In this study, we report the generation of a novel human induced pluripotent stem cell (hiPSC) line from bone marrow mononuclear cells of a patient with multiple myeloma, using an integrative Sendai virus vector. This pluripotent cell line has been shown to differentiate into three germ layers. Therefore, these induced pluripotent stem cells (iPSCs) will enable not only advances in cell therapy products but also the study of mechanisms.

Raspberry-like poly(γ-glutamic acid) hydrogel particles for pH-dependent cell membrane passage and controlled cytosolic delivery of antitumor drugs.

In this research, we synthesized bioderived poly(amino acid) hydrogel particles that showed pH-dependent membrane-disrupting properties and controlled cytosolic delivery of antitumor drugs. Poly(γ-glutamic acid) (γ-PGA) that has been produced extensively using bacteria, especially those of Bacillus subtilis species, was modified with cholesterol (γ-PGA/Chol), and the γ-PGA/Chol conjugates were used to form polymeric nanoparticles the size of 21.0±1.1 nm in aqueous solution. When the polymeric nanoparticles were mixed with doxorubicin (Dox), raspberry-like hydrogel particles (RBHPs) were formed by the electrostatic interaction between the cationically charged Dox and the anionically charged nanoparticles. The average size and surface charge of the RBHPs in aqueous solution were 444.9±122.5 nm and -56.44 mV, respectively. The loaded amount of Dox was approximately 63.9 µg/mg of RBHPs. The RBHPs showed controlled drug release behavior in both in vitro and ex vivo cell-based experiments. Through fluorescence microscopy and fluorescence-activated cell sorting, the cellular uptake of RBHPs into human cervical cancer cells (HeLa) was analyzed. The cytotoxic effect, evaluated by the methyl tetrazolium salt assay, was dependent on both the concentration of RBHPs and the treatment time. The pH-dependent membrane-disrupting properties of the RBHPs and the subsequent cytosolic delivery of Dox were evaluated using a standard hemolysis assay. Upon an increase in hydrophobicity at the lysosomal acidic pH, RBHPs could easily interact, penetrate cell membranes, and destabilize them. Taken together, the data suggested that RBHPs could be used as drug delivery carriers after loading with other therapeutic drugs, such as proteins or small interfering RNA for cancer therapy.

Bio-derived poly(gamma-glutamic acid) nanogels as controlled anticancer drug delivery carriers.

We have developed a novel type of polymer nanogel loaded with anticancer drug based on bio-derived poly(gamma- glutamic acid) (gamma-PGA). gamma-PGA is a highly anionic polymer that is synthesized naturally by microbial species, most prominently in various bacilli, and has been shown to have excellent biocompatibility. Thiolated gamma-PGA was synthesized by covalent coupling between the carboxyl groups of gamma-PGA and the primary amine group of cysteamine. Doxorubicin (Dox)-loaded gamma-PGA nanogels were fabricated using the following steps: (1) an ionic nanocomplex was formed between thiolated gamma-PGA as the negative charge component, and Dox as the positive charge component; (2) addition of poly(ethylene glycol) (PEG) induced hydrogen-bond interactions between thiol groups of thiolated gamma-PGA and hydroxyl groups of PEG, resulting in the nanocomplex; and (3) disulfide crosslinked gamma-PGA nanogels were fabricated by ultrasonication. The average size and surface charge of Dox-loaded disulfide cross-linked gamma-PGA nanogels in aqueous solution were 136.3 +/- 37.6 nm and -32.5 +/- 5.3 mV, respectively. The loading amount of Dox was approximately 38.7 microgram per mg of gamma-PGA nanogel. The Dox-loaded disulfide cross-linked gamma-PGA nanogels showed controlled drug release behavior in the presence of reducing agents, glutathione (GSH) (1- 10 mM). Through fluorescence microscopy and FACS, the cellular uptake of gamma-PGA nanogels into breast cancer cells (MCF-7) was analyzed. The cytotoxic effect was evaluated using the MTT assay and was determined to be dependent on both the concentration and treatment time of gamma-PGA nanogels. The bio-derived gamma-PGA nanogels are expected to be a well-designed delivery carrier for controlled drug delivery applications.

Hyaluronic acid/poly(ß-amino ester) polymer nanogels for cancer-cell-specific NIR fluorescence switch.

Cancer-cell-specific pH-activatable polymer nanogels consisting of CD44-receptor-targeting hyaluronic acid (HA), pH-sensitive poly(ß-amino ester) (PBAE), and near-infrared (NIR) fluorescent indocyanine green (ICG) were synthesized and used to detect cancer cells. The HA/PBAE/ICG-polymer-nanogel-based NIR probe was nonfluorescent outside of tumor cells. After internalization by CD44-receptor-mediated endocytosis, the probe accumulated in the late endosomes or lysosomes where the acidic pH solubilized the PBAE and caused instant disassembly of the polymer nanogel. During endosomal maturation, the encapsulated ICG was released from its quenched state, inducing strong NIR fluorescence recovery. The nanogels generate a highly tumor-specific NIR signal with a reduced background signal.