Tumor-associated macrophages (TAMs) are increasingly considered a viable target for tumor imaging and therapy. Previously, we reported that innovative surface-functionalization of nanoparticles may help target them to TAMs. In this report, using poly(lactic-co-glycolic) acid (PLGA) nanoparticles incorporated with doxorubicin (DOX) (DOX-NPs), we studied the effect of surface-modification of the nanoparticles with mannose and/or acid-sensitive sheddable polyethylene glycol (PEG) on the biodistribution of DOX and the uptake of DOX by TAMs in tumor-bearing mice. We demonstrated that surface-modification of the DOX-NPs with both mannose and acid-sensitive sheddable PEG significantly increased the accumulation of DOX in tumors, enhanced the uptake of the DOX by TAMs, but decreased the distribution of DOX in mononuclear phagocyte system (MPS), such as liver. We also confirmed that the acid-sensitive sheddable PEGylated, mannose-modified DOX-nanoparticles (DOX-AS-M-NPs) targeted TAMs because depletion of TAMs in tumor-bearing mice significantly decreased the accumulation of DOX in tumor tissues. Furthermore, in a B16-F10 tumor-bearing mouse model, we showed that the DOX-AS-M-NPs were significantly more effective than free DOX in controlling tumor growth but had only minimum effect on the macrophage population in mouse liver and spleen. The AS-M-NPs are promising in targeting cytotoxic or macrophage-modulating agents into tumors to improve tumor therapy.

The recent progress in harnessing the efficient and precise method of DNA editing provided by CRISPR/Cas9 is one of the most promising major advances in the field of gene therapy. However, the development of safe and optimally efficient delivery systems for CRISPR/Cas9 elements capable of achieving specific targeting of gene therapy to the location of interest without off-target effects is a primary challenge for clinical therapeutics. Nanoparticles (NPs) provide a promising means to meet such challenges. In this review, we present the most recent advances in developing innovative NP-based delivery systems that efficiently deliver CRISPR-Cas9 constructs and maximize their effectiveness.

Triple-negative breast cancer (TNBC) is the most aggressive form of breast cancer. TNBC is often infiltrated with a large number of macrophages, which in turn promote tumor growth and metastasis. In this study, tumor-associated macrophages (TAMs) were exploited as a target to deliver doxorubicin (DOX), a chemotherapeutic agent, to TNBC using nanoparticles surface-functionalized by i) acid-sensitive sheddable PEGylation and ii) modifying with mannose (i.e. DOX-AS-M-PLGA-NPs). In mice with orthotopic M-Wnt triple-negative mammary tumors, a single intravenous injection of DOX-AS-M-PLGA-NPs significantly reduced macrophage population in tumors within 2 days, and the density of the macrophages recovered slowly. Repeated injections of DOX-AS-M-PLGA-NPs can help maintain the population of the macrophages at a lower level. In M-Wnt tumor-bearing mice that were pre-treated with zoledronic acid to non-selectively deplete macrophages, the TAM-targeting DOX-AS-M-PLGA-NPs were not more effective than the DOX-AS-PLGA-NPs that were not surface-modified with mannose, and thus do not target TAMs, in controlling tumor growth. However, in M-Wnt tumor-bearing mice that were not pre-treated with zoledronic acid, the TAM-targeting DOX-AS-M-PLGA-NPs were significantly more effective than the non-targeting DOX-AS-PLGA-NPs in controlling the tumor growth. The AS-M-PLGA-NPs or other nanoparticles surface-functionalized similarly, when loaded with chemotherapeutic agents commonly used in adjuvant therapy of TNBC, may be developed into targeted therapy of TNBC.

Docetaxel (DCX) is a second generation taxane. It is approved by the U.S. Food and Drug Administration for the treatment of various types of cancer, including breast, non-small cell lung, and head and neck cancers. However, side effects, including those related to Tween 80, an excipient in current DCX formulations, can be severe. In the present study, we developed a novel solid lipid nanoparticle (SLNs) composition of DCX. Trimyristin was selected from a list of high melting point triglycerides as the core lipid component of the SLNs, based on the rate at which the DCX was released from the SLNs and the stability of the SLNs. The trimyristin-based, PEGylated DCX-incorporated SLNs (DCX-SLNs) showed significantly higher cytotoxicity against various human and murine cancer cells in culture, as compared to DCX solubilized in a Tween80/ethanol solution. Moreover, in a mouse model with pre-established tumors, the new DCX-SLNs were significantly more effective than DCX solubilized in a Tween 80/ethanol solution in inhibiting tumor growth without toxicity, likely because the DCX-SLNs increased the concentration of DCX in tumor tissues, but decreased the levels of DCX in major organs such as liver, spleen, heart, lung, and kidney. DCX-incorporated SLNs prepared with one or more high-melting point triglycerides may represent an improved DCX formulation.

Topical 5-fluorouracil (5-FU) is approved for the treatment of superficial basal cell carcinoma and actinic keratosis. However, 5-FU suffers from poor skin permeation. Microneedles have been successfully applied to improve the skin permeability of small and large molecules, and even nanoparticles, by creating micron-sized pores in the stratum corneum layer of the skin. In this report, the feasibility of using microneedles to increase the skin permeability of 5-FU was tested. Using full thickness mouse skin mounted on Franz diffusion apparatus, it was shown that the flux of 5-FU through the skin was increased by up to 4.5-fold when the skin was pretreated with microneedles (500 µm in length, 50 µm in base diameter). In a mouse model with B16–F10 mouse melanoma cells implanted in the subcutaneous space, the antitumor activity of a commercially available 5-FU topical cream (5%) was significantly enhanced when the cream was applied on a skin area that was pretreated with microneedles, as compared to when the cream was simply applied on a skin area, underneath which the tumor cells were implanted, and without pretreatment of the skin with microneedles. Fluorouracil is not approved for melanoma therapy, but the clinical efficacy of topical 5-FU against tumors such as basal cell carcinoma may be improved by integrating microneedle technology into the therapy.

Summary Bacillus Calmette-Guerin (BCG) vaccines are attenuated live strains of Mycobacterium bovis and are among the most widely used vaccines in the world. BCG is proven effective in preventing severe infant meningitis and miliary tuberculosis. Intravesical instillation of BCG is also a standard treatment for non-muscle invasive bladder cancer. In the past few decades, recombinant BCG (rBCG) technology had been extensively applied to develop vaccine candidates against a variety of infectious diseases, including bacterial, viral, and parasite infections, and to improve the efficacy of BCG in bladder cancer therapy. This review is intended to show the vast applications of BCG and rBCG in prevention of infectious diseases and in cancer immunotherapy, with a special emphasis on recent approaches and trends on both pre-clinical and clinical levels.

Propolis is a honeybee product that contains a mixture of natural substances with a broad spectrum of biological activities. However, the clinical application of propolis is limited due to the presence of a myriad of constituents with different physicochemical properties, low bioavailability and lack of appropriate formulations. In this study, a modified injection technique (spraying technique) has been developed for the encapsulation of the Egyptian propolis within liposomal formulation. The effects of three variables (lipid molar concentration, drug loading and cholesterol percentage) on the particle size and poly dispersity index (PDI) were studied using response surface methodology and the Box–Behnken design. Response surface diagrams were used to develop an optimized liposomal formulation of the Egyptian propolis. A comparative study between the optimized liposomal formulation prepared either by the typical ethanol injection method (TEIM) or the spraying method in terms of particle size, PDI and the in-vitro anti-proliferative effect against human melanoma cell line A375 was carried out. The spraying method resulted in the formation of smaller propolis-loaded liposomes compared to TEIM (particle sizes of 90 ± 6.2 nm, and 170 ± 14.7 nm, respectively). Furthermore, the IC50 values against A375 cells were found to be 3.04 ± 0.14, 4.5 ± 0.09, and 18.06 ± 0.75 for spray-prepared propolis liposomes (PP-Lip), TEIM PP-Lip, and propolis extract (PE), respectively. The encapsulation of PE into liposomes is expected to improve its cellular uptake by endocytosis. Moreover, smaller and more uniform liposomes obtained by spraying can be expected to achieve higher cellular uptake, as the ratio of liposomes or liposomal aggregates that fall above the capacity of cell membrane to “wrap” them will be minimized.

There has been growing interest in utilizing small interfering RNA (siRNA) specific to pro-inflammatory cytokines, such as tumor necrosis factor-α ( TNF-α), in chronic inflammation therapy. However, delivery systems that can increase the distribution of the siRNA in chronic inflammation sites after intravenous administration are needed. Herein we report that innovative functionalization of the surface of siRNA-incorporated poly (lactic-co-glycolic) acid (PLGA) nanoparticles significantly increases the delivery of the siRNA in the chronic inflammation sites in a mouse model. The TNF-α siRNA incorporated PLGA nanoparticles were prepared by the standard double emulsion method, but using stearoyl-hydrazone-polyethylene glycol 2000, a unique acid-sensitive surface active agent, as the emulsifying agent, which renders (i) the nanoparticles PEGylated and (ii) the PEGylation sheddable in low pH environment such as that in chronic inflammation sites. In a mouse model of lipopolysaccharide-induced chronic inflammation, the acid-sensitive sheddable PEGylated PLGA nanoparticles showed significantly higher accumulation or distribution in chronic inflammation sites than PLGA nanoparticles prepared with an acid-insensitive emulsifying agent (i.e., stearoyl-amide-polyethylene glycol 2000) and significantly increased the distribution of the TNF-α siRNA incorporated into the nanoparticles in inflamed mouse foot.