β-Caryophyllene Counteracts Chemoresistance Induced by Cigarette Smoke in Triple-Negative Breast Cancer MDA-MB-468 Cells

Abstract

Exposure to cigarette smoke (CS) has been associated with an increased risk of fatal breast cancers and recurrence, along with chemoresistance and chemotherapy impairment. This strengthens the interest in chemopreventive agents to be exploited both in healthy and oncological subjects to prevent or repair CS damage. In the present study, we evaluated the chemopreventive properties of the natural sesquiterpene β-caryophyllene towards the damage induced by cigarette smoke condensate (CSC) in triple negative breast cancer MDA-MB-468 cells. Particularly, we assessed the ability of the sesquiterpene to interfere with the mechanisms exploited by CSC to promote cell survival and chemoresistance, including genomic instability, cell cycle progress, autophagy/apoptosis, cell migration and related pathways. β-Caryophyllene was found to be able to increase the CSC-induced death of MDA-MB-468 cells, likely triggering oxidative stress, cell cycle arrest and apoptosis; moreover, it hindered cell recovery, autophagy activation and cell migration; at last, a marked inhibition of the signal transducer and activator of transcription 3 (STAT3) activation was highlighted: this could represent a key mechanism of the chemoprevention by β-caryophyllene. Although further studies are required to confirm the in vivo efficacy of β-caryophyllene, the present results suggest a novel strategy to reduce the harmful effect of smoke in cancer patients and to improve the survival expectations in breast cancer women.

Characterization of the Chemopreventive Properties of Cannabis sativa L. Inflorescences from Monoecious Cultivars Grown in Central Italy

“…The one-way analysis of variance (one-way ANOVA), followed by Dunnett's multiple comparison Post-Test, was used to analyze the difference between treatments. The concentration-response curves were constructed using the "Hill equation" according to previously published methods [26]. p-values < 0.05 and < 0.01 were considered as significant and very significant, respectively.…”

“…A treatment was considered cytotoxic when the cell viability was less than 70% with respect to the control [87]. Moreover, the most cytotoxic samples were also tested by the Lactate dehydrogenase (LDH) release assay, according to Di Sotto et al [26], in order to highlight any possible damage at the cell membrane level. The LDH levels were normalized per the number of viable cells.…”

“…The 2,7-dichlorofluorescein diacetate assay (DCFH-DA) was performed according to a previous method in order to measure the ROS levels after the treatment with hemp samples [26]. The DCF fluorescence intensity was measured at excitation and emission wavelengths of 485 nm and 535 nm, using a Cytation 1 Cell Imaging Multimode Reader (BioTek, AHSI, Milan, Italy).…”

“…The DCF fluorescence intensity was measured at excitation and emission wavelengths of 485 nm and 535 nm, using a Cytation 1 Cell Imaging Multimode Reader (BioTek, AHSI, Milan, Italy). The results were expressed as a percentage of the negative control after being normalized to viable cells [26].…”

“…To this end, in this study we evaluated the antimutagenic activity in the bacterial reverse mutation assay and the antioxidant power of both the organic and hydroalcoholic extracts from the inflorescence of Felina 32, USO 31, Ferimon and Fedora 17 hemp varieties, collected in June and September, according to previous methods [24,25]. Moreover, the cytotoxicity of the tested samples in human hepatoma cell line HepG2; the leakage of the cytoplasmic lactate dehydrogenase (LDH) enzyme [26]; and the modulation of the glucose-6-phosphate dehydrogenase (G6PDH) enzyme, involved in the pentose phosphate pathway (PPP) and in the regulation of the cell transformation and cancer proliferation [27], were investigated. The effects of the treatments on the intracellular oxidative stress parameters, i.e., reactive oxygen species (ROS) and glutathione levels, were determined according to previous studies [28].…”