Furin-responsive triterpenine-based liposomal complex enhances anticervical cancer therapy through size modulation.

The accumulation and penetration of antitumor drugs in tumor tissues are directly related to their antitumor effects. The particle size of the nanodrug delivery system is one of the most important factors for the accumulation and penetration of antitumor drugs within tumor tissues. Generally, nanodelivery systems of intermediate size (100-120 nm) are capable of efficient accumulation owing to prolonged circulation and enhanced permeability and retention (EPR) effect; however, smaller ones (20-40 nm) are effective for deep penetration within tumor tissue. Currently a conventional drug delivery system cannot possess two types of optimal sizes, simultaneously. To solve this and to enhance cervical cancer treatment, a furin-responsive triterpenine-based liposomal complex (PEGcleavable Tf-CTM/L), with Tf-CTM (transferrin-modified tripterine-loaded coix seed oil microemulsion) in core, coated with a thermo-sensitive lipid and a kind of PEG shell modified with a furin-cleavable peptide was developed to improve tumor-specific accumulation and penetration. Herein, PEGcleavable Tf-CTM/L was capable of efficient accumulation because of EPR effect. The PEG shells could timely detach under stimulation of overexpressed furin protein to solve the problem of the steric hindrance dilemma. The small-sized Tf-CTM released under stimulation of tumor microthermal environment in cervical cancer, which was efficient with regards to deep penetration at tumor sites. Notably, compared to the use of triterpenine alone, PEGcleavable Tf-CTM/L promoted anticervical efficacy and displayed diminished systemic toxicity by efficient accumulation and deep penetration of antitumor drugs within tumor tissues. Our study provides a new strategy, and holds promising potential for anticervical cancer treatment.

Mild-heat-inducible sequentially released liposomal complex remodels the tumor microenvironment and reinforces anti-breast-cancer therapy.

Increasing evidence indicates that the tumor microenvironment (TME) imposes various obstacles in response to chemotherapies. Sodium tanshinone IIA sulfonate (STS) has a validated ability to repair the unfavorable TME, providing a suitable environment for celastrol-based chemotherapy. However, remodeling TME still possesses enormous challenges for STS due to the difficulty in a controlled release at tumor sites. Gold nanorods (GNRs) capable of converting near-infrared (NIR) light into heat offer a promising trigger approach to regulate the local drug release. Here, we fabricated a gold nanorod-anchored thermosensitive liposomal complex co-loaded with STS and celastrol (G-T/C-L), which could sequentially release STS and celastrol upon NIR irradiation at 808 nm. When G-T/C-L reaches the sites, NIR illumination produces mild heat (∼43 °C) and thereby triggers a rapid release of STS in the initial stage, decreasing the level of tumoral blood vessels, collagen, cancer-associated fibroblasts, and Th2 type cytokines. In the subsequent stage, celastrol was unloaded to exert an anticancer effect under an activated TME. In proof-of-concept studies, the treatment of G-T/C-L with NIR illumination showed a significant improvement in anticancer efficacy both in vitro and in vivo but without conventional photothermal therapy-associated side effects. This study proposes photothermal-triggered technology to realize controlled drug release, enriching the application with combinational STS and celastrol in anti-breast cancer therapy.

Non-triggered sequential-release liposomes enhance anti-breast cancer efficacy of STS and celastrol-based microemulsion.

A codelivery system that sequentially releases its contents is an effective strategy to enhance anticancer efficacy. Here, we fabricated multicomponent-based liposomes (T/CM-L) loaded with sodium tanshinone IIA sulfonate (STS) and a small-sized microemulsion of celastrol (CM), which shows synergistic anti-breast cancer activity through the initial release of STS for modulation of the tumor microenvironment, and subsequent release of CM (and its payloads) for eradication of tumor tissues. In vitro studies exhibited that T/CM-L induced massive apoptosis of MCF-7 cells, indicating a coordinated cytotoxicity against cancer cells. Once the liposomes had accumulated at the tumor site, STS was released from T/CM-L in the first place to repair abnormal vessels as well as to decrease the level of fibroblasts. Owing to the barriers of the microemulsion and the liposomes, the celastrol was then unloaded at a moderate rate to kill the tumor cells, which resulted in the shrinkage of the tumor size. Furthermore, T/CM-L displayed diminished systemic toxicity compared to celastrol used alone. Our work offers a novel strategy for combination anticancer treatment and holds promising potential not only for breast cancer treatment, but also for the treatment of other solid tumors.

Preliminary study on fabrication, characterization and synergistic anti-lung cancer effects of self-assembled micelles of covalently conjugated celastrol-polyethylene glycol-ginsenoside Rh2.

The aim of this study was to develop an amphipathic polyethylene glycol (PEG) derivative that was bi-terminally modified with celastrol and ginsenoside Rh2 (Celastrol-PEG-G Rh2). Such derivative was capable of forming novel, celastrol-loaded polymeric micelles (CG-M) for endo/lysosomal delivery and thereby synergistic treatment of lung cancer. Celastrol-PEG-G Rh2 with a yield of 55.6% was first synthesized and characterized. Its critical micellar concentration was 1 × 10-5 M, determined by pyrene entrapment method. CG-M had a small particle size of 121.53 ± 2.35 nm, a narrow polydispersity index of 0.214 ± 0.001 and a moderately negative zeta potential of -23.14 ± 3.15 mV. Celastrol and G Rh2 were rapidly released from CG-M under acidic and enzymatic conditions, but slowly released in normal physiological environments. In cellular studies, the internalization of celastrol and G Rh2 by human non-small cell lung cancer (A549) cells treated with CG-M was 5.8-fold and 1.8-fold higher than that of non-micelle control. Combinational therapy of celastrol and G Rh2 using CG-M exhibited synergistic anticancer activities in cell apoptosis and proliferation assays via rapid drug release within endo/lysosomes. Most importantly, the celastrol in CG-M exhibited a long elimination half-life of 445.3 ± 43.5 min and an improved area under the curve of 645060.8 ± 63640.7 ng/mL/h, that were 1.03-fold and 2.44-fold greater than those of non-micelle control, respectively. These findings suggest that CG-M is a promising vector for precisely releasing anticancer drugs within the tumor cells, and thereby exerts an improved synergistic anti-lung cancer effect.