AbstrAct:Laboratory models show that the beta-blocker, propranolol, can inhibit norepinephrine-induced breast cancer cell migration. We hypothesised that breast cancer patients receiving beta-blockers for hypertension would show reduced metastasis and improved clinical outcome. Three patient subgroups were identified from the medical records of 466 consecutive female patients (median age 57, range 28-71) with operable breast cancer and follow-up (>10 years). Two subgroups comprised 43 and 49 hypertensive patients treated with beta-blockers or other antihypertensives respectively, prior to cancer diagnosis. 374 patients formed a nonhypertensive control group. Metastasis development, disease free interval, tumour recurrence and hazards risk were statistically compared between groups. KaplanMeier plots were used to model survival and DM. Beta-blocker treated patients showed a significant reduction in metastasis development (p=0.026), tumour recurrence (p=0.001), and longer disease free interval (p=0.01). In addition, there was a 57% reduced risk of metastasis (Hazards ratio=0.430; 95% CI=0.200-0.926, p=0.031), and a 71% reduction in breast cancer mortality after 10 years (Hazards ratio=0.291; 95% CI=0.119-0.715, p=0.007). This proof-of-principle study showed beta-blocker therapy significantly reduces distant metastases, cancer recurrence, and cancer-specific mortality in breast cancer patients suggesting a novel role for beta-blocker therapy. A larger epidemiological study leading to randomised clinical trials is needed for breast and other cancer types including colon, prostate and ovary.

Background— Atrial natriuretic peptide (ANP), through its guanylyl cyclase-A (GC-A) receptor, not only is critically involved in the endocrine regulation of arterial blood pressure but also locally moderates cardiomyocyte growth. The mechanisms underlying the antihypertrophic effects of ANP remain largely uncharacterized. We examined the contribution of the Na + /H + exchanger NHE-1 to cardiac remodeling in GC-A–deficient (GC-A −/− ) mice. Methods and Results— Fluorometric measurements in isolated adult cardiomyocytes demonstrated that cardiac hypertrophy in GC-A −/− mice was associated with enhanced NHE-1 activity, alkalinization of intracellular pH, and increased Ca 2+ levels. Chronic treatment of GC-A −/− mice with the NHE-1 inhibitor cariporide normalized cardiomyocyte pH and Ca 2+ levels and regressed cardiac hypertrophy and fibrosis, despite persistent arterial hypertension. To characterize the molecular pathways driving cardiac hypertrophy in GC-A −/− mice, we evaluated the activity of 4 prohypertrophic signaling pathways: the mitogen-activated protein kinases (MAPK), the serine-threonine kinase Akt, calcineurin, and Ca 2+ /calmodulin-dependent kinase II (CaMKII). The results demonstrate that all 4 pathways were activated in GC-A −/− mice, but only CaMKII and Akt activity regressed during reversal of the hypertrophic phenotype by cariporide treatment. In contrast, the MAPK and calcineurin/NFAT signaling pathways remained activated during regression of hypertrophy. Conclusions— On the basis of these results, we conclude that the ANP/GC-A system moderates the cardiac growth response to pressure overload by preventing excessive activation of NHE-1 and subsequent increases in cardiomyocyte intracellular pH, Ca 2+ , and CaMKII as well as Akt activity.

Breast cancer mortality is frequently associated with metastatic disease. Metastasis models have shown adrenoceptor (AR) stimulation induces cell migration which is inhibited by adrenoceptor antagonist drugs. We investigated adrenoceptor protein expression in clinical breast tumours and its association with disease progression and prognosis. Immunohistochemistry on tissue microarrays was used to characterise α1b, α2c and β(2)2 adrenoceptor protein expression in operable breast tumours. Associations with tumour-relevant biological markers and clinical outcome were statistically assessed. Strong α1b expression occurred in large high grade (P < 0.0001), HER2+ (P < 0.0001) or basal-like (CK5/6, P = 0.0005; CK14, P = 0.0001; EGFR, P = 0.003) cancers, showing increased proliferation (Mib1, P = 0.002), decreased apoptosis (Bcl2, P < 0.0001) and poor NPI membership (P = 0.001). α1b expression correlated with poor cancer-specific survival (LR = 7.628, P = 0.022) and tumour recurrence (LR = 6.128, P = 0.047). Strong α2c was over-expressed in high grade (P = 0.007), HER3+ (P = 0.002) and HER4+ (P < 0.0001) cancers with borderline increase in EGFR, p53 and MIB1 proteins, and inverse association with hormonal (PgR, P = 0.002) phenotype. In contrast, strong β(2) expression occurred in small-size, luminal-like (ER+, P < 0.001) tumours of low grade (P < 0.001) and lymph node stage (P = 0.027) that showed poor prognosis when hormonal treatment was withheld. Adrenoceptors were not found to be independent predictors of clinical outcome. Alpha1b and α2c AR is over-expressed in basal-like breast tumours of poor prognosis. Strong β(2) adrenoceptor expression is seen in patients with a luminal (ER+) tumour phenotype and good prognosis, due to benefits derived from hormonal therapy. These findings suggest a possible role for targeted therapy using adrenoceptor antagonists.