Figure 1.

β‐adrenoceptor (β‐AR) ligands have no direct antitumour effects. (A) β1‐ and β2‐adrenoceptor mRNA levels in cultured cancer B16F10 cells. mRNA level was assessed by q‐PCR after being normalized by the mRNA level of GAPDH. Heart tissue samples from β₁‐adrenoceptor knockout (KO) and wild‐type (WT) mice were used as negative and positive controls respectively. B16F10 cells expressed a moderate level of β₂‐adrenoceptors whereas β₁‐adrenoceptors were lacking (n = 10 per group). (B) Tumour cell proliferation. A MTS proliferation assay was used for in vitro assessment of propranolol, a β‐adrenoceptor antagonist, and isoprenaline, a β‐adrenoceptor agonist, effects on B16F10 cancer cell proliferation. Neither isoprenaline nor propranolol had any effect on cancer cell proliferation (n = 10 per group). Data are expressed as percentage of cell viability after treatment with β‐adrenoceptor ligands at different incubation times (24, 48 and 72 h).