Selective accumulation of hybrid liposomes into adult T-cell leukemia cells along with induction of apoptosis

Selective elimination of tumorigenic cells from mixed culture of normal and tumorigenic cells using hybrid liposomes aimed at realizing of cell therapy

While induced pluripotent stem (iPS) cells are expected to be a cell source for regenerative medicine, they also have tumorigenic properties owing to their proliferative potential. During the manufacturing of regenerative medicine products, undifferentiated iPS cells and malignant transformed cells may be mixed in the cell culture population. Therefore, it is essential to eliminate tumorigenic cells selectively. In this study, a mixed culture of normal human fetal hepatocytes (Hc cells) and human hepatocellular carcinoma cells (HuH-7 cells) was used as a cell population model to be used as regenerative medicine products, and the selective elimination of HuH-7 cells by hybrid liposomes (HL) was analyzed. HL tended to fuse and accumulate more in HuH-7 cells due to larger fluidity of plasma membrane for HuH-7 cells than that for Hc cells. In a mixed culture of Hc and HuH-7 cells, HL selectively eliminated HuH-7 cells while allowing Hc cells to remain viable. In addition, HL treatment for the mixed culture of Hc and HuH-7 cells suppressed the tumorigenicity of HuH-7 cells. Therefore, HL selectively fused and accumulated in tumorigenic cells in a mixed cell culture of normal and tumorigenic cells, and eliminated tumorigenic cells while allowing normal cells to remain viable. The results of this study suggest the potential of HL in eliminating tumorigenic cells during the manufacturing of regenerative medicine products. Thus, HL could be expected to contribute to the development of safe regenerative medical products.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-023-00613-y.

Hybrid liposomes showing enhanced accumulation in tumors as theranostic agents in the orthotopic graft model mouse of colorectal cancer

Hybrid liposomes (HLs) can be prepared by simply sonicating a mixture of vesicular and micellar molecules in a buffer solution. This study aimed to elucidate the therapeutic effects and ability of HLs to detect (diagnosis) cancer in an orthotopic graft mouse model of colorectal cancer with HCT116 cells for the use of HLs as theranostic agents. In the absence of a chemotherapeutic drug, HLs exhibited therapeutic effects by inhibiting the growth of HCT116 colorectal cancer cells in vitro, possibly through an increase in apoptosis. Intravenously administered HLs also caused a remarkable reduction in the relative cecum weight in an orthotopic graft mouse model of colorectal cancer. A decrease in tumor size in the cecal sections was confirmed by histological analysis using HE staining. TUNEL staining indicated an induction of apoptosis in HCT116 cells in the orthotopic graft mouse model of colorectal cancer. For the detection (diagnosis) of colorectal cancer by HLs, the accumulation of HLs encapsulating a fluorescent probe (ICG) was observed in HCT116 cells in the in vivo colorectal cancer model following intravenous administration. These data indicate that HLs can accumulate in tumor cells in the cecum of the orthotopic graft mouse model of colorectal cancer for a prolonged period of time, and inhibit the growth of HCT116 cells.

Therapeutic effects of hybrid liposomes without drugs for rheumatoid arthritis

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.

Hybrid liposomes inhibit tumor growth and lung metastasis of murine osteosarcoma cells

Antitumor effects of hybrid liposomes (HL) composed of l-α-dimyristoylphosphatidylcholine (DMPC) and polyoxyethylene(23) dodecyl ether (C₁₂(EO)₂₃) on the metastatic growth of murine osteosarcoma (LM8) cells were investigated in vitro and in vivo. Remarkable inhibitory effects of HL-23 on the growth of LM8 cells were obtained through the induction of apoptotic cell death in vitro. It was also indicated that HL-23 should dramatically suppress the invasion of LM8 cells and the formation of filopodia on the cell surface in vitro. Furthermore, significantly high therapeutic effects were observed in the homograft mouse models of LM8 cells with lung metastasis after the treatment with HL-23 in vivo. That is, the histological analysis demonstrated that the primary tumor growth of LM8 cells implanted subcutaneously into the mice was inhibited along with the induction of apoptosis. In addition, it was found that HL-23 significantly decreased the lung metastasis of LM8 cells in the mouse models through the inhibition of primary tumor invasion. These results suggest that HL-23 could be a novel agent for the chemotherapy of osteosarcoma.

Selective accumulation and growth inhibition of hybrid liposomes to human hepatocellular carcinoma cells in relation to fluidity of plasma membranes

Hybrid liposomes (HLs), composed of l-α-dimyristoylphosphatidylcholine (DMPC) and polyoxyethylene(23) dodecyl ether, have selectively inhibited the growth of human hepatocellular carcinoma (HCC) cells without affecting normal hepatocytes to trigger apoptosis via caspase-3 activation. Furthermore, HLs distinguished between the HCC and normal cells which had higher and lower membrane fluidities respectively, then fused and accumulated preferentially into the membranes of HCC cells. It is noteworthy that the anti-cancer activity of HLs correlated well with the fluidity of cell membranes for HCC and other cancer cells. These results suggest that HLs could target cancer cell-membranes in relation to their lipid fluidity that provide the possibility of novel nanotherapy for intractable cancer.

Hybrid liposomes affect cellular lipid constituents and caveolae structures

We examined alterations of lipid constituents induced by hybrid liposomes (HLs) in cancer cells. As early as 1h after HL treatment, amounts of the raft/caveolae lipids sphingomyelin, ceramide, and ether-type PC were altered. In addition, the structures of caveolae on the cytoplasmic surface of the cell membrane were significantly changed. Our results suggest that alterations of lipid composition in caveolae mediate HL signaling for apoptosis.