Contribution of the Local RAS to Hematopoietic Function: A Novel Therapeutic Target

Adjuvant combination chemotherapy with cyclophosphamide, methotrexate, and fluorouracil was administered after radical mastectomy for primary breast cancer with histologically positive axillary lymph nodes to assess whether it would improve treatment outcome as compared with surgery alone. Here we report a 20-year follow-up of this investigation. In 1973 we began a trial involving 386 women who were randomly assigned to receive either no further treatment after radical mastectomy (179 women) or 12 monthly cycles of adjuvant combination chemotherapy (207 women). All patients were admitted to the Istituto Nazionale Tumori in Milan, Italy. Adjuvant chemotherapy was delivered in the outpatient clinic of the Division of Medical Oncology. After a median follow-up of 19.4 years, the patients given adjuvant combination chemotherapy had significantly better rates of relapse-free survival (unadjusted relative risk of relapse, 0.71; 95 percent confidence interval, 0.56 to 0.90; P = 0.004; adjusted relative risk, 0.65, 95 percent confidence interval, 0.51 to 0.83; P < 0.001) and total survival (unadjusted relative risk of death, 0.78; 95 percent confidence interval, 0.62 to 0.99; P = 0.04; adjusted relative risk, 0.76; 95 percent confidence interval, 0.60 to 0.97; P = 0.03). With the exception of postmenopausal women, a benefit from adjuvant chemotherapy was evident in all subgroups of patients. The long-term results of this trial of adjuvant combination chemotherapy confirm our preliminary observations of the effectiveness of the treatment in women with node-positive breast cancer.

It is well known that the RAS (renin-angiotensin system) plays a key role in the modulation of many functions in the body. AngII (angiotensin II) acting on AT1R (type 1 AngII receptor) has a central role in mediating most of the actions of the RAS. However, over the past 10 years, several studies have presented evidence for the existence of a new arm of the RAS, namely the ACE (angiotensin-converting enzyme) 2/Ang-(1-7) [angiotensin-(1-7)]/Mas axis. Ang-(1-7) can be produced from AngI or AngII via endo- or carboxy-peptidases respectively. ACE2 appears to play a central role in Ang-(1-7) formation. As described for AngII, Ang-(1-7) also has a broad range of effects in different organs and tissues which goes beyond its initially described cardiovascular and renal actions. Those effects are mediated by Mas and can counter-regulate most of the deleterious effects of AngII. The interaction Ang-(1-7)/Mas regulates different signalling pathways, such as PI3K (phosphoinositide 3-kinase)/AKT and ERK (extracellularsignal-regulated kinase) pathways and involves downstream effectors such as NO, FOXO1 (forkhead box O1) and COX-2 (cyclo-oxygenase-2). Through these mechanisms, Ang-(1-7) is able to improve pathological conditions including fibrosis and inflammation in organs such as lungs, liver and kidney. In addition, this heptapeptide has positive effects on metabolism, increasing the glucose uptake and lipolysis while decreasing insulin resistance and dyslipidaemia. Ang-(1-7) is also able to improve cerebroprotection against ischaemic stroke, besides its effects on learning and memory. The reproductive system can also be affected by Ang-(1-7) treatment, with enhanced ovulation, spermatogenesis and sexual steroids synthesis. Finally, Ang-(1-7) is considered a potential anti-cancer treatment since it is able to inhibit cell proliferation and angiogenesis. Thus the ACE2/Ang-(1-7)/Mas pathway seems to be involved in many physiological and pathophysiological processes in several systems and organs especially by opposing the detrimental effects of inappropriate overactivation of the ACE/AngII/AT1R axis.

Both total dose and dose intensity of adjuvant chemotherapy are postulated to be important variables in the outcome for patients with operable breast cancer. The Cancer and Leukemia Group B study 8541 examined the effects of adjuvant treatment using conventional-range dose and dose intensity in female patients with stage II (axillary lymph node-positive) breast cancer. Within 6 weeks of surgery (radical mastectomy, modified radical mastectomy, or lumpectomy), 1550 patients with unilateral breast cancer were randomly assigned to one of three treatment arms: high-, moderate-, or low-dose intensity. The patients received cyclophosphamide, doxorubicin, and 5-fluorouracil on day 1 of each chemotherapy cycle, with 5-fluorouracil administration repeated on day 8. The high-dose arm had twice the dose intensity and twice the drug dose as the low-dose arm. The moderate-dose arm had two thirds the dose intensity as the high-dose arm but the same total drug dose. Disease-free survival and overall survival were primary end points of the study. At a median follow-up of 9 years, disease-free survival and overall survival for patients on the moderate- and high-dose arms are superior to the corresponding survival measures for patients on the low-dose arm (two-sided P<.0001 and two-sided P = .004, respectively), with no difference in disease-free or overall survival between the moderate- and the high-dose arms. At 5 years, overall survival (average +/- standard error) is 79% +/- 2% for patients on the high-dose arm, 77% +/- 2% for the patients on the moderate-dose arm, and 72% +/- 2% for patients on the low-dose arm; disease-free survival is 66% +/- 2%, 61% +/- 2%, and 56% +/- 2%, respectively. Within the conventional dose range for this chemotherapy regimen, a higher dose is associated with better disease-free survival and overall survival.