Here, we report the synthesis and evaluation of dual drugloaded nanoparticles as an effective means to deliver carfilzomib and doxorubicin to multiple myeloma tumor cells at their optimal synergistic ratio. First, various molar ratios of carfilzomib to doxorubicin were screened against multiple myeloma cell lines to determine the molar ratio that elicited the greatest synergy using the Chou-Talalay method. The therapeutic agents were then incorporated into liposomes at the optimal synergistic ratio of 1:1 to yield dual drug-loaded nanoparticles with a narrow size range of 115 nm and high reproducibility. Our results demonstrated that the dual drug-loaded liposomes exhibited synergy in vitro and were more efficacious in inhibiting tumor growth in vivo than a combination of free drugs, while at the same time reducing systemic toxicity. Taken together, this study presents the synthesis and preclinical evaluation of dual drug-loaded liposomes containing carfilzomib and doxorubicin for enhanced therapeutic efficacy to improve patient outcome in multiple myeloma.

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Currently, there is great interest in the development of ways to achieve the benefits of radiation treatments with reduced negative effects. The present study demonstrates the utilization of radio-luminescent particles (RLPs) as a means to achieve radio-sensitization and enhancement and their ability to affect head- and neck-cancer-cell cultures (in vitro) and xenografts (in vivo). Our approach utilizes a naturally abundant radio-luminescent mineral, calcium tungstate (CaWO4), in its micro or nanoparticulate form for generating secondary UV-A light by γ ray or X-ray photons. In vitro tests demonstrate that unoptimized RLP materials (uncoated CaWO4 (CWO) microparticles (MPs) and PEG–PLA-coated CWO nanoparticles (NPs)) induce a significant enhancement of the tumor-suppressive effect of X-rays and γ rays in both radio-sensitive- and radio-resistant-cancer models; uncoated CWO MPs and PEG–PLA-coated CWO NPs demonstrate comparable radio-sensitization efficacies in vitro. Mechanistic studies reveal that concomitant CaWO4 causes increased mitotic death in radio-resistant cells treated with radiation, whereas CaWO4 sensitizes radio-sensitive cells to X-ray-induced apoptosis and necrosis. The radio-sensitization efficacy of intratumorally injected CaWO4 particles (uncoated CWO MPs and PEG–PLA-coated CWO NPs) is also evaluated in vivo in mouse head- and neck-cancer xenografts. Uncoated CWO MPs suppress tumor growth more effectively than PEG–PLA-coated CWO NPs. On the basis of theoretical considerations, an argument is proposed that uncoated CWO MPs release subtoxic levels of tungstate ions, which cause increased photoelectric-electron-emission effects. The effect of folic acid functionalization on the in vitro radio-sensitization behavior produced by PEG–PLA-coated CWO NPs is studied. Surface folic acid results in a significant improvement in the radio-sensitization efficiency of CaWO4.

Radiation therapy is a primary treatment modality for many forms of cancer. Normally, the highest tolerable dose of ionizing radiation is used to treat tumors, but limitations imposed by normal tissue complications present challenges for local tumor control. In light of this, a class of compounds called radio-sensitizers have been developed to enhance the effectiveness of radiation. Many of these are small molecule drugs found to interact favorably with radiation therapy, but recent advances have been made using nanoparticles as radio-sensitizers. Herein, we report the utilization of radio-luminescent calcium tungstate nanoparticles that emit photoelectrons, UV-A, and visible light during X-ray irradiation, acting as effective radio-sensitizers (“Radio Luminescence Therapy”). In addition, a folic acid-functionalized form of these nanoparticles was shown to enhance radio-sensitization in vitro and in murine models of head and neck cancer. Folic acid-functionalized particles were found to decrease UV-A-induced clonogenic cell survival relative to nonfunctionalized particles. Several possible mechanisms were explored, and the folic acid-functionalized particles were found to mediate this increase in efficacy likely by activating pro-proliferative signaling through folate’s innate mitogenic activity, leading to decreased repair of UV-A-induced DNA lesions. Finally, a clinical case study of a canine sarcoma patient demonstrated the initial safety and feasibility of translating these folic acid-functionalized particles into the clinic as radio-sensitizers in the treatment of spontaneous tumors.

Photodynamic therapy (PDT) has shown potential as a cancer treatment modality, but its clinical application is limited due to its visible-light activation since visible wavelengths of light cannot penetrate tissues well. Additionally, combination therapies utilizing PDT and radiotherapy have shown clinical promise in several cancers but are limited again by light penetration and the need for selective photosensitization of the treatment area. Herein, we report the development of bilirubin-photodynamic nanoparticles (PEGylated bilirubin-encapsulated CaWO4 nanoparticles or “PEG-BR/CWO NPs”). PEG-BR/CWO NPs are a formulation of PEGylated bilirubin micelles encapsulating CaWO4 nanoparticles. These particles are capable of activating PDT via X-ray irradiation within deep tissues due to the radioluminescence properties of their CaWO4 nanoparticle cores. PEG-BR/CWO NPs facilitate a combination of photodynamic and radiation therapy and represent a previously unexplored application of PEG-bilirubin conjugates as photosensitizing agents. When irradiated by X-rays, PEG-BR/CWO NPs emit UV-A and visible light from their CaWO4 cores, which excites bilirubin and leads to the production of singlet oxygen. PEG-BR/CWO NPs exhibit improvements over X-ray therapy alone in vitro and in murine xenograft models of head and neck cancer. The data presented in this study indicate that PEG-BR/CWO NPs are promising agents for facilitating combined radio-photodynamic therapy in deep tissue tumors.