Treatment of natural mammary gland tumors in canines and felines using gold nanorods-assisted plasmonic photothermal therapy to induce tumor apoptosis

Abstract

Plasmonic photothermal therapy (PPTT) is a cancer therapy in which gold nanorods are injected at the site of a tumor before near-infrared light is transiently applied to the tumor causing localized cell death. Previously, PPTT studies have been carried out on xenograft mice models. Herein, we report a study showing the feasibility of PPTT as applied to natural tumors in the mammary glands of dogs and cats, which more realistically represent their human equivalents at the molecular level. We optimized a regime of three low PPTT doses at 2-week intervals that ablated tumors mainly via apoptosis in 13 natural mammary gland tumors from seven animals. Histopathology, X-ray, blood profiles, and comprehensive examinations were used for both the diagnosis and the evaluation of tumor statuses before and after treatment. Histopathology results showed an obvious reduction in the cancer grade shortly after the first treatment and a complete regression after the third treatment. Blood tests showed no obvious change in liver and kidney functions. Similarly, X-ray diffraction showed no metastasis after 1 year of treatment. In conclusion, our study suggests the feasibility of applying the gold nanorods-PPTT on natural tumors in dogs and cats without any relapse or toxicity effects after 1 year of treatment.

Gold Nanorod Photothermal Therapy Alters Cell Junctions and Actin Network in Inhibiting Cancer Cell Collective Migration

“…In these studies, we observed that animals with induced or spontaneous tumors were effectively cured with no tumor reoccurrence or metastasis. 14,16,17 Our recent in vitro studies also revealed AuNPs and PPTT inhibit cancer cell migration and invasion. 12,18 However, the mechanism of how AuNPs treatments inhibit cancer cell migration remains largely unresolved.…”

Gold Nanorod-Assisted Photothermal Therapy Decreases Bleeding during Breast Cancer Surgery in Dogs and Cats

“…The NIR light capable of deeply penetrating the tissue is transiently applied to the tumor, producing localized heat that could lead to tumor necrosis and apoptosis [3]. PPTT modulation to induce cell apoptosis might be a more favorable option than triggering necrosis, as during necrosis, the broken plasma membrane leads to the leaking of cytoplasmic components and inflammation, which could further induce cancer growth and metastasis [4,5,6,7]. The high efficiency of PPTT in getting rid of cancer cells by inducing apoptosis has been demonstrated both in vitro and in vivo [3,8].…”

“…In many animal cases, the tumors often metastasize. We have shown the efficacy of this treatment in tumor-bearing mice [8,11] and have recently demonstrated the treatment of mammary carcinoma in dogs and cats, where the malignant mammary tumors of ≤20 cm 3 in volume could be treated by intratumoral inoculation of AuNRs, followed by PPTT [5]. During these studies, we observed that animals with induced or spontaneous tumors have noteworthy regression without any recurrence nor metastasis.…”

“…Our recent studies have also shown the ability of gold nanorod-assisted plasmonic photothermal therapy (AuNRs-PPTT) in vitro to inhibit cancer cell migration [12,13]. In addition, the toxicity of this treatment has been examined in mice, dogs, and cats, which indicates that there are no toxic effects on the animals for long periods of time [5,8]. Therefore, PPTT is believed to be a favorable alternative for treating solid tumors with relatively small sizes and preventing metastasis [14].…”

<p>Nanomaterial-Based Tumor Photothermal Immunotherapy</p>

“…Finally, the mode of cell death was thought to be apoptosis. Ali et al 114 developed a mild PTT strategy to induce cancer cell apoptosis, by fixing the GNRs concentration (7.5 nM), laser power (5.8 w/ cm 2 ) and adjusting the laser exposure time. They irradiated the human breast cancer (MCF-7) cells and found that after 2 min laser exposure, the cells mainly apoptosis (42.7% apoptosis and 2.89% necrosis), while 5 min laser exposure led to a significant increase in necrosis cells (20.17% apoptosis and 15.5% necrosis).…”