Multidrug resistance (MDR) is a major impediment to cancer treatment. A promising strategy for treating MDR is the joint delivery of combined anticancer agents to tumor cells in a single nanocarrier. Here, for the first time, Resveratrol (Res) was co-encapsulated with paclitaxel (PTX) in a PEGylated liposome to construct a carrier-delivered form of combination therapy for drug-resistant tumors. The composite liposome had an average diameter of 50 nm with encapsulated efficiencies of above 50%. The studies demonstrated that the composite liposome could generate potent cytotoxicity against the drug-resistant MCF-7/Adr tumor cells in vitro and enhance the bioavailability and the tumor-retention of the drugs in vivo. Moreover, systemic therapy with the composite liposome effectively inhibited drug-resistant tumor in mice (p < 0.01), without any notable increase in the toxicity. These results suggested that the co-delivery of Res and a cytotoxic agent in a nanocarrier may potentially improve the treatment of drug-resistant tumors.

MUC1 protein is an attractive target for anticancer drug delivery owing to its overexpression in most adenocarcinomas. In this study, a reported MUC1 protein aptamer is exploited as the targeting agent of a nanoparticle-based drug delivery system. Paclitaxel (PTX) loaded poly (lactic-co-glycolic-acid) (PLGA) nanoparticles were formulated by an emulsion/evaporation method, and MUC1 aptamers (Apt) were conjugated to the particle surface through a DNA spacer. The aptamer conjugated nanoparticles (Apt-NPs) are about 225.3 nm in size with a stable in vitro drug release profile. Using MCF-7 breast cancer cell as a MUC1-overexpressing model, the MUC1 aptamer increased the uptake of nanoparticles into the target cells as measured by flow cytometry. Moreover, the PTX loaded Apt-NPs enhanced in vitro drug delivery and cytotoxicity to MUC1⁺ cancer cells, as compared with non-targeted nanoparticles that lack the MUC1 aptamer (P<0.01). The behavior of this novel aptamer-nanoparticle bioconjugates suggests that MUC1 aptamers may have application potential in targeted drug delivery towards MUC1-overexpressing tumors.

Chemotherapy is a primary treatment for cancer, but its efficacy is often limited by the adverse effects of cytotoxic agents. Targeted drug delivery may reduce the non-specific toxicity of chemotherapy by selectively directing anticancer drugs to tumor cells. MUC1 protein is an attractive target for tumor-specific drug delivery owning to its overexpression in most adenocarcinomas. In this study, a novel MUC1 aptamer is exploited as the targeting ligand for carrying doxorubicin (Dox) to cancer cells. We developed an 86-base DNA aptamer (MA3) that bound to a peptide epitope of MUC1 with a K_d of 38.3 nM and minimal cross reactivity to albumin. Using A549 lung cancer and MCF-7 breast cancer cells as MUC1-expressing models, MA3 was found to preferentially bind to MUC1-positive but not MUC1-negative cells. An aptamer-doxorubicin complex (Apt-Dox) was formulated by intercalating doxorubicin into the DNA structure of MA3. Apt-Dox was found capable of carrying doxorubicin into MUC1-positive tumor cells, while significantly reducing the drug intake by MUC1-negative cells. Moreover, Apt-Dox retained the efficacy of doxorubicin against MUC1-positive tumor cells, but lowered the toxicity to MUC1-negative cells (P<0.01). The results suggest that the MUC1 aptamer may have potential utility as a targeting ligand for selective delivery of cytotoxic agent to MUC1-expressing tumors.

Aptamer-guided DNA tetrahedron as a novel targeted drug delivery system for MUC1-expressing breast cancer cells in vitro Aptamer-guided DNA Tetrahedron as a Novel Targeted Drug Delivery System for MUC1-expressing Breast Cancer Cells in vitro

With the expansion of the potential applications of carbon nanotubes (CNT) in biomedical fields, the toxicity and biocompatibility of CNT have become issues of growing concern. Since the immune system often mediates tissue damage during pathogenesis, it is important to explore whether CNT can trigger cytotoxicity through affecting the immune functions. In the current study, we evaluated the influence of CNT on the cytotoxicity mediated by human lymphocytes in vitro. The results showed that while CNT at low concentrations (0.001 to 0.1 µg/ml) did not cause obvious cell death or apoptosis directly, it enhanced lymphocyte-mediated cytotoxicity against multiple human cell lines. In addition, CNT increased the secretion of IFN-γ and TNF-α by the lymphocytes. CNT also upregulated the NF-κB expression in lymphocytes, and the blockage of the NF-κB pathway reduced the lymphocyte-mediated cytotoxicity triggered by CNT. These results suggest that CNT at lower concentrations may prospectively initiate an indirect cytotoxicity through affecting the function of lymphocytes.

The application of nanomaterial in cancer treatment is promising and intriguing. Anti-tumor immunotherapy has the potential to significantly improve the prognosis of cancer treatment, though the efficacy of immunotherapy generally needs further improvement. One way to improve the efficacy is using immune adjuvants, but the adjuvants for anticancer immunotherapy have to be more potent than for prophylactic vaccines. Here, we report that compared to conventional alum adjuvant, aluminum oxide nanoparticles (nano-alum) may further enhance the anticancer effects of an immunotherapy that employs tumor cell vaccine (TCV). The average tumor size tends to be lower in animals that receive the combinational treatment of nano-alum and TCV. The anticancer cytotoxicity by the lymphocytes was also significantly higher in the treatment group that received both TCV and nano-alum. These results suggest that nano-alum may potentially serve as a potent immune adjuvant and have prospective applications in anticancer immunotherapy.