Optimization of the classical oral cancerization protocol in hamster to study oral cancer therapy

Golden Syrian Hamster Models for Cancer Research

The golden Syrian hamster (Mesocricetus auratus) has long been a valuable rodent model of human diseases, especially infectious and metabolic diseases. Hamsters have also been valuable models of several chemically induced cancers such as the DMBA-induced oral cheek pouch cancer model. Recently, with the application of CRISPR/Cas9 genetic engineering technology, hamsters can now be gene targeted as readily as mouse models. This review describes the phenotypes of three gene-targeted knockout (KO) hamster cancer models, TP53, KCNQ1, and IL2RG. Notably, these hamster models demonstrate cancer phenotypes not observed in mouse KOs. In some cases, the cancers that arise in the KO hamster are similar to cancers that arise in humans, in contrast with KO mice that do not develop the cancers. An example is the development of aggressive acute myelogenous leukemia (AML) in TP53 KO hamsters. The review also presents a discussion of the relative strengths and weaknesses of mouse cancer models and hamster cancer models and argues that there are no perfect rodent models of cancer and that the genetically engineered hamster cancer models can complement mouse models and expand the suite of animal cancer models available for the development of new cancer therapies.

Boron Neutron Capture Therapy (BNCT) Mediated by Maleimide-Functionalized Closo-Dodecaborate Albumin Conjugates (MID:BSA) for Oral Cancer: Biodistribution Studies and In Vivo BNCT in the Hamster Cheek Pouch Oral Cancer Model

Background: BNCT (Boron Neutron Capture Therapy) is a tumor-selective particle radiotherapy that combines preferential boron accumulation in tumors and neutron irradiation. Although p-boronophenylalanine (BPA) has been clinically used, new boron compounds are needed for the advancement of BNCT. Based on previous studies in colon tumor-bearing mice, in this study, we evaluated MID:BSA (maleimide-functionalized closo-dodecaborate conjugated to bovine serum albumin) biodistribution and MID:BSA/BNCT therapeutic effect on tumors and associated radiotoxicity in the hamster cheek pouch oral cancer model. Methods: Biodistribution studies were performed at 30 mg B/kg and 15 mg B/kg (12 h and 19 h post-administration). MID:BSA/BNCT (15 mg B/kg, 19 h) was performed at three different absorbed doses to precancerous tissue. Results: MID:BSA 30 mg B/kg protocol induced high BSA toxicity. MID:BSA 15 mg B/kg injected at a slow rate was well-tolerated and reached therapeutically useful boron concentration values in the tumor and tumor/normal tissue ratios. The 19 h protocol exhibited significantly lower boron concentration values in blood. MID:BSA/BNCT exhibited a significant tumor response vs. the control group with no significant radiotoxicity. Conclusions: MID:BSA/BNCT would be therapeutically useful to treat oral cancer. BSA toxicity is a consideration when injecting a compound conjugated to BSA and depends on the animal model studied.

Role of animal models in biomedical research: a review

The animal model deals with the species other than the human, as it can imitate the disease progression, its’ diagnosis as well as a treatment similar to human. Discovery of a drug and/or component, equipment, their toxicological studies, dose, side effects are in vivo studied for future use in humans considering its’ ethical issues. Here lies the importance of the animal model for its enormous use in biomedical research. Animal models have many facets that mimic various disease conditions in humans like systemic autoimmune diseases, rheumatoid arthritis, epilepsy, Alzheimer’s disease, cardiovascular diseases, Atherosclerosis, diabetes, etc., and many more. Besides, the model has tremendous importance in drug development, development of medical devices, tissue engineering, wound healing, and bone and cartilage regeneration studies, as a model in vascular surgeries as well as the model for vertebral disc regeneration surgery. Though, all the models have some advantages as well as challenges, but, present review has emphasized the importance of various small and large animal models in pharmaceutical drug development, transgenic animal models, models for medical device developments, studies for various human diseases, bone and cartilage regeneration model, diabetic and burn wound model as well as surgical models like vascular surgeries and surgeries for intervertebral disc degeneration considering all the ethical issues of that specific animal model. Despite, the process of using the animal model has facilitated researchers to carry out the researches that would have been impossible to accomplish in human considering the ethical prohibitions.

The Effect of Low-Dose Gamma Irradiation on the Uptake of Boronophenylalanine to Enhance the Efficacy of Boron Neutron Capture Therapy in an Orthotopic Oral Cancer Model

The success of boron neutron capture therapy (BNCT) mainly depends on the boron concentration in the tumor and a high tumor/normal tissue (T/N) boron ratio or a high tumor/blood (T/B) boron ratio. Therefore, the effective enhancement of boron ratios is the first priority. Our study investigated whether a low-dose of γ-radiation (LDR) could improve boron ratios and enhance the therapeutic effects of BNCT in an orthotopic human oral squamous cell carcinoma-bearing animal model. SAS/luc cells were used to establish the orthotopic tumor-bearing model. The pharmacokinetics of boronophenylalanine (BPA) administration with 400 mg/kg of body weight both alone and in combination with LDR (0.1 Gy) was evaluated, and BNCT was performed at the Tsing Hua Open-pool Reactor (THOR). The radiation doses were evaluated using a treatment planning system. Moreover, tumor growth and metastasis were monitored via bioluminescence imaging (BLI). The therapeutic effects after BNCT were evaluated using BLI, histopathological findings and the overall survival rate. LDR increased the BPA accumulation in tumors by 52.2%. T/N and T/B ratios were enhanced from 3.77 to 5.31 and from 3.47 to 4.46, respectively. Radiation dose was increased by 44.3%. Notably, tumor recurrence and cervical lymph node metastasis were observed in the BNCT group, which had a survival rate of 50%. Complete responses were found in the combined-treatment group, which had a survival rate of 100%. No toxicity was found according to the histopathological findings. Conclusively, LDR increased BPA accumulation in the tumor and the T/N and T/B ratios, resulting in BNCT efficacy improvement and the overall survival rate extension.