Enhanced antitumor effect of targeted nanoliposomal bleomycin

Bleomycin-loaded folic acid-conjugated nanoliposomes: a novel formulation for targeted treatment of oral cancer

Introduction

Targeted delivery of anticancer drugs holds great promise for enhancing therapeutic efficacy while minimizing adverse effects. The folate receptor (FR)-mediated approach offers a selective strategy to target cancer cells overexpressing FR. Bleomycin, an established antitumor antibiotic, suffers from limited efficacy due to poor diffusion into tumor cells. This study examined the anti-cancer potential of folate-targeted liposomal Bleomycin (FL-BLEOMYCIN) in comparison to non-targeted L-BLEOMYCIN on oral cavity cancer (CAL27). The study also investigated FL-Bleomycin's capacity to halt the cell cycle in the G2/M phase using flow cytometry.

Methods

FL-Bleomycin was produced using thin-layer hydration, followed by incorporation of folic acid into nanoliposomes. To evaluate the release profile, drug release tests were carried out. Cytotoxicity of FL-Bleomycin, L-Bleomycin, and traditional Bleomycin was evaluated using cell viability assays. The cell cycle arrest caused by FL-Bleomycin was examined using flow cytometry. Finally, FL-Bleomycin uptake studies were performed to assess the internalization of FL-Bleomycin by CAL27 cells.

Results

Compared to L-Bleomycin and traditional Bleomycin, FL-Bleomycin showed noticeably more cytotoxicity against CAL 27 cells. The effective arrest of CAL 27 cells in the G2/M phase of the cell cycle by FL-Bleomycin was verified by flow cytometry. Uptake studies revealed increased internalization of FL-Bleomycin by CAL 27 cells compared to standard formulations. Drug release studies showed a consistent, non-explosive release profile. Cells treated with these nanoliposomes, compared to control groups, exhibited a dose-dependent decrease in the intensity of the 170-kDa EGF-R band as observed by Western blot analysis.

Discussion

The findings suggest that FL-Bleomycin is a potential method for delivering drugs precisely in tumors expressing folic acid receptors. Its potential for successful cancer treatment is shown by its higher internalization, improved cytotoxicity, and cell cycle prevention in CAL 27 cells. To find out how effective FL-Bleomycin is in vivo and whether it may be used to treat other FR-expressing tumors, more research is necessary.

Diagnostic and therapeutic evaluation of folate-targeted paclitaxel and vinorelbine encapsulating theranostic liposomes for non-small cell lung cancer

NSCLC is the most common type of lung cancer. However, non-specific contrast agents, radiopharmaceuticals, and treatment methods are insufficient in early diagnosis and eradication of all tumor tissue. Therefore, the formulation of a novel, targeted, specific theranostic agents possess critical importance. In our previous study, paclitaxel and vinorelbine encapsulating, Tc-99m radiolabeled, folate targeted, nanosized liposomes were formulated and found promising due to characterization properties, high cellular uptake, and cytotoxicity. In this study, in vivo therapeutic and diagnostic efficacy of liposomal formulations were tested by biodistribution study, evaluation of tumor growth inhibition, and histopathologic examination after in vitro assays on LLC1 cells. Both actively and passively targeted liposomal formulations exhibited high cellular uptake, and co-drug encapsulating liposomes showed a greater cytotoxicity profiles than free drug combination in LLC1 cells. By the results of biodistribution studies performed in NSCLC tumor-bearing C57BL/6 mice, the uptake of radiolabeled, actively folate targeted, co-drug encapsulating liposomal formulation was found to be higher in tumor tissue when compared to non-actively targeted one. Also, more effective treatment was achieved by using folate-targeted, co-drug encapsulating liposomal formulation when compared to free drugs combination according to changes in tumor size of mice. Furthermore, liposomal formulations showed lower toxicity compared to free drug combinations in the toxicity study considering body weight. Moreover, according to the histopathological study, folate targeted, co-drug encapsulating liposomes not only inhibited the tumor growth effectively but also restricted the lung metastasis entirely.

Targeting folate receptor β positive tumor-associated macrophages in lung cancer with a folate-modified liposomal complex

Tumor-associated macrophages (TAMs) facilitate cancer progression by promoting tumor invasion, angiogenesis, metastasis, inflammatory responses, and immunosuppression. Folate receptor β (FRβ) is overexpressed in TAMs. However, the clinical significance of FRβ-positive macrophages in lung cancer remains poorly understood. In this study, we verified that FRβ overexpression in lung cancer TAMs was associated with poor prognosis. We utilized a folate-modified lipoplex comprising a folate-modified liposome (F-PLP) delivering a BIM-S plasmid to target both lung cancer cells and FRβ-positive macrophages in the tumor microenvironment. Transfection of LL/2 cells and MH-S cells with F-PLP/pBIM induced cell apoptosis. Injection of F-PLP/pBIM into LL/2 and A549 lung cancer models significantly depleted FRβ-positive macrophages and reduced tumor growth. Treatment of tumor-bearing mice with F-PLP/pBIM significantly inhibited tumor growth in vivo by inducing tumor cell and macrophage apoptosis, reducing tumor proliferation, and inhibiting tumor angiogenesis. In addition, a preliminary safety evaluation demonstrated a good safety profile of F-PLP/pBIM as a gene therapy administered intravenously. This work describes a novel application of lipoplexes in lung cancer targeted therapy that influences the tumor microenvironment by targeting TAMs.

Bleomycin-Loaded pH-Sensitive Polymer⁻Lipid-Incorporated Liposomes for Cancer Chemotherapy

Cancer chemotherapeutic systems with high antitumor effects and less adverse effects are eagerly desired. Here, a pH-sensitive delivery system for bleomycin (BLM) was developed using egg yolk phosphatidylcholine liposomes modified with poly(ethylene glycol)-lipid (PEG-PE) for long circulation in the bloodstream and 2-carboxycyclohexane-1-carboxylated polyglycidol-having distearoyl phosphatidylethanolamine (CHexPG-PE) for pH sensitization. The PEG-PE/CHexPG-PE-introduced liposomes showed content release responding to pH decrease and were taken up by tumor cells at a rate 2.5 times higher than that of liposomes without CHexPG-PE. BLM-loaded PEG-PE/CHexPG-PE-introduced liposomes exhibited comparable cytotoxicity with that of the free drug. Intravenous administration of these liposomes suppressed tumor growth more effectively in tumor-bearing mice than did the free drug and liposomes without CHexPG-PE. However, at a high dosage of BLM, these liposomes showed severe toxicity to the spleen, liver, and lungs, indicating the trapping of liposomes by mononuclear phagocyte systems, probably because of recognition of the carboxylates on the liposomes. An increase in PEG molecular weight on the liposome surface significantly decreased toxicity to the liver and spleen, although toxicity to the lungs remained. Further improvements such as the optimization of PEG density and lipid composition and the introduction of targeting ligands to the liposomes are required to increase therapeutic effects and to reduce adverse effects.