Olive oil's bitter principle reverses acquired autoresistance to trastuzumab (Herceptin™) in HER2-overexpressing breast cancer cells

Table 1 Effects of EVOO phenolics on breast cancer cell viability

	TYROSOL			HYDROXYTYROSOL			OLEUROPEIN AGLYCONE			OLEUROPEIN GLYCOSIDE
	IC₃₀	IC₅₀	IC₇₀	IC₃₀	IC₅₀	IC₇₀	IC₃₀	IC₅₀	IC₇₀	IC₃₀	IC₅₀	IC₇₀
MCF-7	N.A.	N.A.	N.A.	N.A.	N.A.	N.A.	~105	N.A.	N.A.	N.A.	N.A.	N.A.
MCF-7/HER2	N.A.	N.A.	N.A.	N.A.	N.A.	N.A.	35 (95% CI = 30–40)	85 (95% CI = 82–88)	N.A.	N.A.	N.A.	N.A.
SK-Br3	~120	N.A.	N.A.	~110	N.A.	N.A.	28 (95% CI = 25–31)	47 (95% CI = 43–51)	82 (95% CI = 80–84)	~110	N.A.	N.A.

The metabolic status of tyrosol-, hydroxytyrosol-, oleuropein aglycone-, and oleuropein glycoside-treated MCF-7, MCF-7/(pBABE)HER2 and SKBR3 breast cancer cells was evaluated using a MTT-based cell viability assay and constructing dose-response curves as described in "Methods". Inhibitory Concentrations (IC) producing the IC₃₀, IC₅₀ and IC⁷⁰ values (the concentration of each agent needed to reduce cell viability by 30%, 50% and 70% relative to untreated control cells, respectively) were calculated by interpolation. Values are means (in μM) and 95% confidence intervals (95% CI) of three independent experiments made in triplicate.
N.A. Not Available.

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