Evaluation of Antitumor Activity of Hesperetin-Loaded Nanoparticles Against DMBA-Induced Oral Carcinogenesis Based on Tissue Autofluorescence Spectroscopy and Multivariate Analysis.

The present study is designed to understand the nature of endogenous fluorophores and cellular metabolism that occur in the experimental oral carcinogenesis and to assess their feasibility for antitumor efficacy of hesperetin-loaded nanoparticles (HETNPs) in comparison with native hesperetin (HET) against 7,12-dimethyl benz(a) anthracene (DMBA)-induced oral carcinogenesis using fluorescence spectroscopy. The fluorescence emission spectra of the control and the experimental buccal mucosa are recorded at an excitation wavelength of 320 nm with an emission ranging from 350 to 550 nm. The results show that there is a reduced contribution from the emission of collagen, nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), in DMBA-induced tumor tissues as compared with the control tissues. Furthermore, there was significant decrease in the optical redox ratio [(FAD/ (NADH + FAD)] is observed in DMBA-induced tumor tissues, which indicates an increased metabolic activity when compared to the control tissues. Oral administration of HET and its nanoparticulates restored the status of endogenous fluorophores emission and would have a higher redox ratio in the buccal mucosa of DMBA painted animals. Taken together, the treatment of nanoparticulate hesperetin was found to be more effective than native hesperetin in improving the status of endogenous fluorophores to a near normal range in DMBA-induced hamster buccal pouch carcinogenesis. The results of this study raise the important possibility that fluorescence spectroscopy in conjunction with PC-LDA has tremendous potential for monitor or potentially predict response to therapy.

Chemopreventive efficacy of naringenin-loaded nanoparticles in 7,12-dimethylbenz(a)anthracene induced experimental oral carcinogenesis.

Nanochemoprevention has been introduced recently as a novel approach for improving phytochemicals bioavailability and anti-tumor effect. The present study is designed to evaluate the chemopreventive efficacy of prepared naringenin-loaded nanoparticles (NARNPs) relative to efficacy of free naringenin (NAR) against 7,12-dimethyl benz(a)anthracene (DMBA)-induced oral carcinogenesis by evaluating the status of lipid peroxidation, antioxidants and immunoexpression patterns of proliferating cell nuclear antigen (PCNA) and p53 proteins. Transmission electron microscope (TEM) and dynamic light scattering (DLS) investigations have confirmed a narrow size distribution of the prepared nanoparticles (40-90 nm) with ~88 % encapsulation efficiency. Oral squamous cell carcinoma (OSCC) was developed in the buccal pouch of golden Syrian hamsters by painting with 0.5 % DMBA in liquid paraffin three times a week for 14 weeks. DMBA painted animals revealed the morphological changes, hyperplasia, dysplasia and well-differentiated squamous cell carcinoma. Moreover, the status of lipid peroxidation, antioxidants and immunoexpression of PCNA and p53 were significantly altered during DMBA-induced oral carcinogenesis. Oral administration of NARNPs (50 mg NAR/kg body weight/day) to DMBA-treated animals completely prevented the tumor formation as compared to the free NAR and significantly reduced the degree of histological lesions, in addition to restoration of the status of biochemical and molecular markers during oral carcinogenesis. In addition, NARNPs have more potent anti-lipid peroxidative, antiproliferative effect and antioxidant potentials compared to free NAR in DMBA-induced oral carcinogenesis. In conclusion, the present study suggests that NARNPs could be a potentially useful drug carrier system for targeted delivery of naringenin for cancer chemoprevention.