Table 1 Fifty percent inhibitory concentration (IC₅₀) and combination index (CI) of Clarithromycin, Irinotecan, 5-Fluorouracil, Cisplatin, and Oxaliplatin for the reported cancer cell lines.

(a) IC₅₀ values of Clarithromycin for different cell lines
Drug	Cell line		IC₅₀ (μM)
Clarithromycin
	HCT116		80.0 ± 2.0
	HT29		125.3 ± 16.8
	LS174T		154.4 ± 9.1
	HCT116 p53^−/−		150.0 ± 8.6
	HEK293		>200
	HEK293-MOCK		>200
	HEK293-hERG1		92.4 ± 4.9
(b) IC₅₀ and IC₂₅ values of Irinotecan (CPT11), 5-Fluorouracil (5-FU), Cisplatin (Cis), and Oxaliplatin (Oxa), and their combination index (CI) with Clarithromycin for HCT116 cells
Drug	IC₅₀ (μM)	IC₂₅ (μM)	CI at IC₅₀ (effect)	CI at IC₂₅ (effect)
CPT-11	10.1 ± 2.1	2.1 ± 0.1	0.63 ± 0.09 (S)	0.41 ± 0.02 (S)
5-FU	13.7 ± 2.4	2.21 ± 0.1	0.57 ± 0.07 (S)	0.38 ± 0.03 (S)
Cis	25.2 ± 2.1 (Ref. ⁵⁰)	9.04 ± 0.7	1.38 ± 0.06 (A)	0.87 ± 0.15 (S)
Oxa	57.4 ± 9.4 (Ref. ⁵⁰)	12.2 ± 3.0	1.10 ± 0.11 (A)	0.78 ± 0.10 (S)
(c) IC₅₀ and IC₂₅ values of Clarithromycin and 5-Fluorouracil for HCT116 cells cultured as spheroids
Drug	IC₅₀ (μM)		IC₂₅ (μM)
Clarithromycin	>300		191.8 ± 21.3
5-FU	260.8 ± 4.6		41.7 ± 8.9

(a) IC₅₀ values were determined after 24 h of treatment by the Trypan Blue exclusion test, using Origin Software. Data are means ± SEM of four independent experiments, each carried out in triplicate. (b) HCT116 cells were exposed to Irinotecan (CPT-11), 5-Fluorouracil (5-FU), Cisplatin (Cis) or Oxaliplatin (Oxa) alone or in combination with Cla for 24 h as described in ref. ⁵⁰. IC₅₀ and IC₂₅ vales were determined as in (a). For the determination of the CI the drugs were used at their IC₅₀ and IC₂₅ values. CI values were calculated using Calcusyn software Version 2 (Biosoft). CI > 1, antagonism (A); CI = 1, additivity (Ad); CI < 1, synergy (S). Data are means ± SEM of three independent experiments, each carried out in triplicate. (c) Three-dimensional spheroids were treated for 24 h and IC₅₀ values were determined using Origin Software, after the calculation of the effect of drugs on 3D spheroids volume by Matlab, as reported in Materials and Methods. Data are means ± SEM of five sample for each concentration (n = 2 independent experiments).

Search