Masayo Umebayashi

Intravenous injection of hybrid liposomes suppresses the liver metastases in xenograft mouse models of colorectal cancer in vivo.

Therapeutic effects of hybrid liposomes (HL) composed of l-α-dimyristoylphosphatidylcholine (DMPC) and polyoxyethylene(25) dodecyl ether (C(12)(EO)(25)) on the metastasis of human colon carcinoma (HCT116) cells were examined in vivo. Remarkably high therapeutic effects were obtained in the xenograft mouse models of colorectal cancer (CRC) liver metastases after treatment with HL-25 on the basis of relative liver weight and histological analysis of the liver tissue sections of mouse models with HE staining, and TUNEL staining for detection of apoptotic cells. The survival effects of HL-25 were obtained using xenograft mouse models of CRC liver metastases. Furthermore, with regard to pharmacokinetics, the accumulation of fluorescent labeled HL-25 was observed in the liver tissue of xenograft mouse models of CRC liver metastases for 24 h after the intravenous injection of fluorescent labeled HL-25. Therapeutic effects of HL without any drugs on the liver metastasis of human CRC were revealed for the first time in vivo.

Chemotherapy with hybrid liposomes for acute lymphatic leukemia leading to apoptosis in vivo

Hybrid liposomes (HL) composed of 95 mol% l-α-dimyristoylphosphatidylcholine (DMPC) and 5 mol% polyoxyethylene (25) dodecyl ether (C(12)(EO)(25)) were prepared by sonication. A clear solutions of HL-25 having hydrodynamic diameter of about 50 nm could be maintained over 3 weeks. Remarkable reduction of tumor volume in model mice of acute lymphatic leukemia (ALL) intravenously treated with HL-25 without drugs after the subcutaneously inoculation of human ALL (MOLT-4) cells was verified in vivo. Induction of apoptosis in tumor of model mice of ALL treated with HL-25 was observed in micrographs on the basis of TUNEL method. Remarkable decrease of the ascites in ALL model mice treated with HL-25 was observed. It is noteworthy that prolonged survival (>400%) was obtained in model mice of ALL after the treatment with HL-25 without drugs.

CD24 suppresses malignant phenotype by downregulation of SHH transcription through STAT1 inhibition in breast cancer cells

Hedgehog (Hh) signaling has been found to be activated in breast cancer stem cells (BCSCs). However, the precise role of the BCSCs marker, CD24, remains unclear. Here, we describe a relationship between CD24 and Sonic Hedgehog (SHH), and reveal a role for this relationship in the induction of a malignant phenotype of breast cancer. CD24 siRNA-transfected breast cancer cells (BCCs) demonstrated higher expression of SHH and GLI1, increased anchorage-independent proliferation, and enhanced invasiveness and superior tumorigenicity compared with control. Conversely, CD24 forced-expressing BCCs possessed decreased SHH and GLI1 expression, anchorage-independent proliferation, and invasiveness. Suppression of SHH decreased invasiveness through inhibition of matrix metalloproteinase (MMP)-2 expression, GLI1 expression, anchorage-independent proliferation, tumorigenicity, and tumor volume in vivo in CD24 siRNA transfected BCCs. DNA microarray analysis identified STAT1 as a relationship between CD24 and SHH. CD24 siRNA-transfected BCCs with concurrent STAT1 inhibition exhibited decreased SHH expression, invasiveness, anchorage-independent proliferation, tumorigenicity, and tumor volume in vivo. These results suggest that CD24 suppresses development of a malignant phenotype by down-regulating SHH transcription through STAT1 inhibition. CD24 gene transfer or STAT1 inhibition may represent new effective therapeutic strategies to target refractory breast cancer.

Therapeutic effects of hybrid liposomes without drugs for rheumatoid arthritis

Abstract Hybrid liposomes (HLs) can be prepared by simply sonicating a mixture of vesicular and micellar molecules in buffer solutions. This study aims to demonstrate inhibitory effects of HLs on the growth of fibroblast-like synoviocytes along with apoptosis and therapeutic effects of HLs in a mouse model with rheumatoid arthritis (RA). HLs composed of 95 mol% l-α-dimyristoylphosphatidylcholine (DMPC) and 5 mol% polyoxyethylene(23)dodecyl ether (C12(EO)23) were prepared by the sonication method. The inhibitory effects of HLs on the growth of human fibroblast-like synoviocytes-RA (HFLS-RA) cells in vitro and their inhibitory mechanism were examined. High inhibitory effects of HLs on the growth of HFLS-RA cells were observed. The induction of apoptosis by HLs was revealed on the basis of flow cytometric analysis. Furthermore, therapeutic effects of HLs in the mouse model with RA were examined in vivo. Our results demonstrate that HLs showed inhibitory effects on the growth of HFLS-RA cells in vitro along with apoptosis and therapeutic effects in mouse models of RA in vivo.

The Hedgehog inhibitor suppresses the function of monocyte-derived dendritic cells from patients with advanced cancer under hypoxia.

Immunotherapy using monocyte derived dendritic cells (Mo-DCs) from cancer patients has been developed; however, the Mo-DCs regularly studied have been derived from non-cancer bearing donors or mice, and evaluated in normoxic conditions. In the present study, we investigated the effects of Hedgehog (Hh) inhibitors which are being developed as molecular target drugs for cancer on the functions of Mo-DCs derived from patients with advanced cancer when cultured in a tumor-like hypoxic environment. Mo-DC induction, migration, chemotaxis, phagocytosis, maturation, IL-12 p40 or p70 secretion and the allogeneic lymphocyte stimulation activity of Mo-DCs from patients with advanced cancer were all significantly inhibited by the Hh inhibitor, cyclopamine under hypoxic conditions. Our results suggest that Hh signaling plays an important role in the maintenance and function of Mo-DCs derived from patients with advanced cancer when cultured under hypoxic conditions.

Inhibitory effects of hybrid liposomes on the growth of synoviocyte causing rheumatoid arthritis.

Inhibitory effects of HL-n composed of 95 mol% L-α-dimyristoylphosphatidylcholin (DMPC) and 5 mol% polyoxyethylenedodecylether (C(12)(EO)(n), n = 21, 23, or 25) on the growth of human rheumatoid arthritis (RA) fibroblast-like synoviocytes (HFLS-RA) in vitro were examined. Remarkably high inhibitory effects of HL-n on the growth of HFLS-RA cells were obtained. The induction of apoptosis by HL-n was revealed on the basis of TUNEL method. Furthermore, the therapeutic effects of HL-23 using mouse models of arthritis were investigated. Therapeutic effects without joint swelling were obtained in mouse models of RA treated with HL.

The Hedgehog inhibitor cyclopamine impairs the benefits of immunotherapy with activated T and NK lymphocytes derived from patients with advanced cancer.

Hedgehog (Hh) signaling is activated in various types of cancer and contributes to the progression, proliferation, and invasiveness of cancer cells. Many Hh inhibitors are undergoing clinical trial and show promise as anticancer drugs. Hh signaling is also induced in the activated T and NK (TNK) lymphocytes that are used in immunotherapy. Activated TNK lymphocyte therapy is anticipated to work well within a tumor’s hypoxic environment. However, most studies on the immunobiological functions of activated TNK lymphocytes have been conducted on healthy donor samples, under normoxic conditions. In the present study, we evaluated the effects of Hh inhibition and oxygen concentrations on the function of activated TNK lymphocytes derived from patients with advanced cancer. Proliferation, migration, surface NKG2D expression, and cytotoxicity were all significantly inhibited, and IFN-γ secretion was significantly increased upon Hh inhibitor treatment of activated TNK lymphocytes under hypoxic conditions in vitro. Tumors from mice injected with cyclopamine-treated activated TNK lymphocytes showed a significant increase in tumor size and had fewer apoptotic cells compared with the tumors in mice injected with control activated TNK lymphocytes. These results suggest that Hh signaling plays a pivotal role in activated TNK lymphocyte cell function. Combination therapy using Hh inhibitors and activated TNK lymphocytes derived from patients with advanced cancer may not be advantageous.

RBPJ and MAML3: Potential therapeutic targets for small cell lung cancer

Background/Aim: Small cell lung cancer (SCLC) is still a deadly type of cancer for which there are few effective therapeutic strategies. Development of a new molecule targeting agent is urgently desired. Previously we showed that recombination signal binding protein for immunoglobulin-kappa-J region (RBPJ) and mastermind-like 3 (MAML3) are new therapeutic targets for pancreatic cancer. In the present study, we analyzed whether RBPJ/MAML3 inhibition could also be a new therapeutic strategy for SCLC. Materials and Methods: Using silencing of RBPJ/MAML3, proliferation, invasion, migration and chemosensitivity of SBC-5 cells were investigated. Results: RBPJ/MAML3 inhibition reduced Smoothened and HES1 expression, suggesting that RBPJ/MAML3 signaling was through Hedgehog and NOTCH pathways. In the analysis of cell functions, RBPJ/MAML3 inhibition significantly reduced proliferation and invasiveness via reduction of expression of matrix metalloproteinases. On the other hand, RBPJ/MAML3 inhibition also reduced chemosensitivity to cis-diamminedichlo-roplatinum and gemcitabine. Conclusion: These results suggest that RBPJ and MAML3 could be new therapeutic targets for SCLC, however, chemosensitivity may be reduced in combinational use with other chemo-therapeutic agents.

Catumaxomab with activated T-cells efficiently lyses chemoresistant EpCAM-positive triple-negative breast cancer cell lines

Background/Aim: Epithelial cell adhesion molecule (EpCAM) is expressed in various types of cancer, including breast cancer, and is correlated with metastasis, invasion, therapeutic resistance and prognosis. Moreover, several cell surface markers, such as CD44 and EpCAM, are molecular targets on cancer stem-like cells of breast cancer. The aim of this study was to investigate whether catumaxomab, a clinical-grade bispecific antibody that binds to both EpCAM on tumor cells and CD3 on T-cells, combined with activated T-cells can eliminate chemoresistant triple-negative breast cancer (TNBC) cells in vitro. Materials and Methods: First, a cell line (MUK-BC1) was established from human breast carcinoma cells derived from a patient with chemoresistant and disseminated breast cancer. These EpCAM-positive TNBC cells were almost completely resistant to various drug-mediated cytotoxicities up to a concentration of 10 μg/ml. Results: Pre-treatment with catumaxomab and subsequent addition of interleukin-2/OKT3-activated autologous T-cells eliminated EpCAM-positive TNBC cells. Conclusion: Catumaxomab combined with activated T-cells may be a potent therapeutic modality to overcome chemoresistant EpCAM-positive TNBC cells.

Hedgehog signaling regulates PDL-1 expression in cancer cells to induce anti-tumor activity by activated lymphocytes

We investigated whether hypoxia-induced activation of Hh signaling contributes to PDL-1 expression in cancer and whether it affects the anti-tumor function of activated lymphocytes. Hypoxia augmented PDL-1 expression and inhibition of Hh signaling reduced PDL-1 expression under hypoxia. When activated lymphocytes were cocultured with cancers treated with a Hh inhibitor, activated lymphocyte cell numbers increased under hypoxia. In contrast, this increase was abrogated when cancer cells were treated with a PDL-1 neutralizing antibody. These results suggest that Hh signaling is one of regulatory pathways of PDL-1 expression under hypoxia and that inhibiting Hh signaling may induce lymphocyte anti-tumor activity.