Anticancer Activities of Thymus vulgaris L. in Experimental Breast Carcinoma In Vivo and In Vitro

Abstract

Naturally-occurring mixtures of phytochemicals present in plant foods are proposed to possess tumor-suppressive activities. In this work, we aimed to evaluate the antitumor effects of Thymus vulgaris L. in in vivo and in vitro mammary carcinoma models. Dried T. vulgaris (as haulm) was continuously administered at two concentrations of 0.1% and 1% in the diet in a chemically-induced rat mammary carcinomas model and a syngeneic 4T1 mouse model. After autopsy, histopathological and molecular analyses of rodent mammary carcinomas were performed. In addition, in vitro evaluations using MCF-7 and MDA-MB-231 cells were carried out. In mice, T. vulgaris at both doses reduced the volume of 4T1 tumors by 85% (0.1%) and 84% (1%) compared to the control, respectively. Moreover, treated tumors showed a substantial decrease in necrosis/tumor area ratio and mitotic activity index. In the rat model, T. vulgaris (1%) decreased the tumor frequency by 53% compared to the control. Analysis of the mechanisms of anticancer action included well-described and validated diagnostic and prognostic markers that are used in both clinical approach and preclinical research. In this regard, the analyses of treated rat carcinoma cells showed a CD44 and ALDH1A1 expression decrease and Bax expression increase. Malondialdehyde (MDA) levels and VEGFR-2 expression were decreased in rat carcinomas in both the T. vulgaris treated groups. Regarding the evaluations of epigenetic changes in rat tumors, we found a decrease in the lysine methylation status of H3K4me3 in both treated groups (H3K9m3, H4K20m3, and H4K16ac were not changed); up-regulations of miR22, miR34a, and miR210 expressions (only at higher doses); and significant reductions in the methylation status of four gene promoters—ATM serin/threonine kinase, also known as the NPAT gene (ATM); Ras-association domain family 1, isoform A (RASSF1); phosphatase and tensin homolog (PTEN); and tissue inhibitor of metalloproteinase-3 (TIMP3) (the paired-like homeodomain transcription factor (PITX2) promoter was not changed). In vitro study revealed the antiproliferative and proapoptotic effects of essential oils of T. vulgaris in MCF-7 and MDA-MB-231 cells (analyses of 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS); 5-bromo-20-deoxyuridine (BrdU); cell cycle; annexin V/PI; caspase-3/7; Bcl-2; PARP; and mitochondrial membrane potential). T. vulgaris L. demonstrated significant chemopreventive and therapeutic activities against experimental breast carcinoma.

Fluctuations of Histone Chemical Modifications in Breast, Prostate, and Colorectal Cancer: An Implication of Phytochemicals as Defenders of Chromatin Equilibrium

“…Furthermore, our group recently described the chemopreventive abilities of plant natural substances mediated via various mechanisms, including modulation of epigenetic modifications. Clove buds administered in diet significantly increased H4K20me3 and H4K16ac [30] and Thymus vulgaris decreased H3K4me3 in a rat model of chemically induced mammary carcinogenesis [14]. Importantly, all these changes represent positive impacts on epigenetic modifications in mammary carcinoma.…”

“…Plant-derived bioactive molecules (phytochemicals) are of particular interest within oncological research. Numerous phytochemicals or natural mixtures of plant compounds present in whole foods show significant antitumor properties via multiple cell signaling pathways and mechanisms, and thus, represent perspective and potentially effective tools for chemoprevention and targeted therapy of cancer disease [14,30,[169][170][171][172]. Moreover, an administration of dietary phytochemicals is the way of a cost-effective and readily applicable clinical approach in the management of cancer, including the most commonly occurring BC, PC, and CRC.…”

“…Extensive oncological research demonstrated that plant natural compounds may be effective in targeting epigenetic alterations associated with the cancer promotion and progression as well as the primary chemoprevention by affecting the carcinogenesis in early stages during initiation [167]. A great amount of phytochemicals exerted anticancer activities via modulation of PHMs, as was demonstrated mainly in in vitro as well as in vivo preclinical studies focusing on BC, PC, and CRC [14,118,133,141,142,146,157,160,172]. However, the usefulness of phytochemicals within clinical approaches is not sufficiently investigated in this topic.…”

“…Furthermore, antineoplastic efficacy of plant natural compounds can be mediated via epigenome modulatory mechanisms maintaining gene expression, DNA damage, or repair mechanisms [12]. In addition to the regulation of miRNA [13][14][15][16] expression or DNA methylation [14,[16][17][18], plant natural compounds may also regulate posttranslational histone modifications (PHMs) [19].…”

“…The application of individual patterns of histone modifications, mainly acetylation and methylation of histones H3 and H4 and their amino acid, residuesserve as perspective tools that bridge personalized medicine and epigenetics [25,26]. Advances in preclinical and clinical cancer research constantly indicate important anticancer activities of plant-derived compounds in cancer chemoprevention and treatment [6,9,10,14,[27][28][29][30]. Therefore, this review summarizes anticancer effectiveness of dietary phytochemicals, either isolated or mixtures, mediated via their abilities to modulate PHMs associated with PC, BC, and CRC, which are included among the most common cancer types in women and men.…”