Anti-proliferative and cytotoxic activities of Allium autumnale P. H. Davis (Amaryllidaceae) on human breast cancer cell lines MCF-7 and MDA-MB-231

BACKGROUND

Natural products obtained from plants can be potent sources for developing a variety of pharmaceutical products. Allium species have been widely studied for their anti-cancer effects and presented promising results as potential anti-cancer agents. Breast cancer (BCa) is one of the most commonly diagnosed types of cancer in women. In this study, we aimed to investigate the anti-proliferative, cytotoxic and anti-metastatic effects of bulb and stem extracts from Allium autumnale P. H. Davis (Amaryllidaceae), an endemic Allium species to the island of Cyprus, in a comparative approach to weakly metastatic MCF-7 and strongly metastatic MDA-MB-231 breast cancer (BCa) cell lines.

METHODS

Possible cytotoxic, anti-proliferative and anti-metastatic effects of the Allium extracts on MCF-7 and MDA-MB-231 cells were tested using trypan blue exclusion, MTT and wound heal assays, respectively. Gas Chromatography Mass Spectroscopy (GC-MS) analysis was performed to determine the prominent medically important compounds in Allium autumnale bulb (AAB) and Allium autumnale stem (AAS) extracts. Student unpaired t-test or ANOVA followed by Newman-Keuls post hoc analysis (INSTAT Software) was used where appropriate.

RESULTS

Our results demonstrate that AAB extract (24, 48 and 72 h) exerts significant anti-proliferative effect on both MCF-7 and MDA-MB-231 cells where this effect for AAS extract was observed only at high (5000 and 10,000 μg/mL) concentrations. Cell viability experiments revealed that AAB extract incubations caused more cytotoxicity on both BCa cell lines compared to the AAS. In contrast, there was no effect on lateral motilities of either cell line.

CONCLUSION

Overall, our studies demonstrated the anti-cancer activities associated with Allium autumnale, revealing it's cytotoxic and anti-proliferative potential to be further utilized in in vivo studies.

DCE- and DW-MRI as early imaging biomarkers of treatment response in a preclinical model of triple negative breast cancer

This work evaluates quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted MRI (DW-MRI) parameters as early biomarkers of response in a preclinical model of triple negative breast cancer (TNBC). The standard Tofts' model of DCE-MRI returns estimates of the volume transfer constant (K^trans ) and the extravascular extracellular volume fraction (v_e ). DW-MRI returns estimates of the apparent diffusion coefficient (ADC). Mice (n = 38) were injected subcutaneously with MDA-MB-231. Tumors were grown to approximately 275 mm³ and sorted into the following groups: saline controls, low-dose Abraxane (15 mg/kg) and high-dose Abraxane (25 mg/kg). Animals were imaged at days zero, one and three. On day three, tumors were extracted for immunohistochemistry. The positive percentage change in ADC on day one was significantly higher in both treatment groups relative to the control group (p < 0.05). In addition, the positive percentage change in K^trans was significantly higher than controls (p < 0.05) on day one for the high-dose group and on days one and three for the low-dose group. The percentage change in tumor volume was significantly different between the high-dose and control groups on day three (p = 0.006). Histology confirmed differences at day three through reduced numbers of proliferating cells (Ki67 staining) in the high-dose group (p = 0.03) and low-dose group (p = 0.052) compared with the control group. Co-immunofluorescent staining of vascular maturity [using von Willebrand Factor (vWF) and α-smooth muscle actin (α-SMA)] indicated significantly higher vascular maturation in the low-dose group compared with the controls on day three (p = 0.03), and trending towards significance in the high-dose group compared with controls on day three (p = 0.052). These results from quantitative imaging with histological validation indicate that ADC and K^trans have the potential to serve as early biomarkers of treatment response in murine studies of TNBC.