Angiotensin-converting enzyme and its association with outcome in lung cancer

Angiotensin converting enzyme inhibitors and risk of lung cancer: A systematic review and meta-analysis

BACKGROUND

We performed a meta-analysis to determine whether a consistent relationship exists between the use of angiotensin converting enzyme inhibitors (ACEIs) and the risk of lung cancer. Accordingly, we summarized and reviewed previously published quantitative studies.

METHODS

Eligible studies with reference lists published before June 1st, 2019 were obtained from searching several databases. Random effects' models were used to summarize the overall estimate of the multivariate adjusted odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

Thirteen observational studies involving 458,686 ACEI users were included in the analysis, Overall, pooled risk ratios indicate that ACEIs use was not a risk factor for lung cancer (RR 0.982, 95% C.I. 0.873 - 1.104; P = .76). There was significant heterogeneity between the studies (Q = 52.54; P < .001; I2 = 86.07). There was no significant association between ACEIs use and lung cancer in studies with over five years of ACEIs exposure (RR 0.95, 95% C.I. 0.75 - 1.20; P = .70); and ≤ 5years of exposure to ACEIs (RR 0.98, 95% C.I. 0.83 - 1.15; P = .77). There were no statistically significant differences in the pooled risk ratio obtained according to the study design (Q = 0.65; P = .723) and the comparator regimen (Q = 3.37; P = .19).

CONCLUSIONS

The use of ACEIs was not associated with an increased risk of lung cancer. Nevertheless, well-designed observational studies with different ethnic populations are still needed to evaluate the long-term (over 10 years) association between ACEIs use and lung cancer.

Risk of lung cancer and renin-angiotensin blockade: a concise review

Purpose

The blockade of the renin–angiotensin–aldosterone system (RAAS) by angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) is one of the most common treatments for hypertension, heart failure and renal diseases. However, concerns have been raised about a possible link between RAAS-blockers and an increased risk of cancer, particularly of lung cancer. This narrative review aims to give a critical appraisal of current evidence and to help physicians understand potential links between RAAS blockade and de novo lung cancer development.

Methods

Numerous pharmaco-epidemiologic studies, mostly retrospective cohort analyses, evaluated the association of RAAS blockade with lung cancer incidence and reported inconsistent findings. Meta-analyses could not further clarify a possible link between RAAS blockade and the risk of lung cancer.

Results

International regulatory agencies (FDA, EMA) have concluded that the use of RAAS blockers is not associated with an increased risk of developing lung cancer. Co-administration of RAAS blockers to systemic therapy of advanced non-small cell lung cancer seems to have positive effects on the outcome.

Conclusion

Until more comprehensive analyses have been completed, there is no need to change clinical practise. Additional prospective randomized trials with long-term follow-up are needed to investigate the effects of these drugs on the development and progression of lung cancer.

Tissue ACE phenotyping in lung cancer

Background

Pulmonary vascular endothelium is the main metabolic site for Angiotensin I-Converting Enzyme (ACE)-mediated degradation of several biologically-active peptides (angiotensin I, bradykinin, hemo-regulatory peptide Ac-SDKP). Primary lung cancer growth and lung cancer metastases decrease lung vascularity reflected by dramatic decreases in both lung and serum ACE activity. We performed precise ACE phenotyping in tissues from subjects with lung cancer.

Methodology

ACE phenotyping included: 1) ACE immunohistochemistry with specific and well-characterized monoclonal antibodies (mAbs) to ACE; 2) ACE activity measurement with two ACE substrates (HHL, ZPHL); 3) calculation of ACE substrates hydrolysis ratio (ZPHL/HHL ratio); 4) the pattern of mAbs binding to 17 different ACE epitopes to detect changes in ACE conformation induced by tumor growth (conformational ACE fingerprint).

Results

ACE immunostaining was dramatically decreased in lung cancer tissues confirmed by a 3-fold decrease in ACE activity. The conformational fingerprint of ACE from tumor lung tissues differed from normal lung (6/17 mAbs) and reflected primarily higher ACE sialylation. The increase in ZPHL/HHL ratio in lung cancer tissues was consistent with greater conformational changes of ACE. Limited analysis of the conformational ACE fingerprint in normal lung tissue and lung cancer tissue form the same patient suggested a remote effect of tumor tissue on ACE conformation and/or on “field cancerization” in a morphologically-normal lung tissues.

Conclusions/Significance

Local conformation of ACE is significantly altered in tumor lung tissues and may be detected by conformational fingerprinting of human ACE.

EXPRESSION OF THE RENIN-ANGIOTENSIN SYSTEM COMPONENTS IN ONCOLOGIC DISEASES

The literature devoted to changes in the expression of the renin-angiotensin system (RAS) proteins of cancer cells was analyzed. The dynamics of RAS protein expression in malignant tumors and the possible role of epigenetic mechanisms in these processes are briefly reviewed. Through research of the epigenetic mechanisms in cancer, principally new techniques for their correction based on the use of selective regulatory systems of covalent modification of histone proteins (for example, deacetylase inhibitor) and microRNA synthesis technologies have been developed. Literature data show promising pharmacological correction of epigenetic modification of chromatin in the treatment of cancer.

Renin-Angiotensin system blockers may prolong survival of metastatic non-small cell lung cancer patients receiving erlotinib

The aim of this study is to determine whether renin-angiotensin system blockers (RASBs), which include angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-2 receptor 1 blockers (ARBs), improve the overall survival (OS) of patients with metastatic non-small cell lung cancer (NSCLC).The medical charts of 117 patients with metastatic NSCLC were retrospectively assessed. Thirty-seven patients (RASB group) using RASBs during systemic treatment were compared with 80 controls (control group) who did not use RASBs following the diagnosis of NSCLC. The histological tumor subtype, performance status, age, sex, smoking status, comorbidities, other medications, chemotherapeutics (CT), and erlotinib that were received in any line of treatment were recorded. We compared the OS of the patients in the RASB and control groups.The median (±SD) age of the patients was 61 (±1) years and all patients were administered systemic treatment (CT or erlotinib). The patients in RASB group were more likely to be smokers, have hypertension and ischemic heart disease, and use erlotinib, thiazides, beta-blockers, and calcium-channel blockers (P < 0.05 for all) compared with the control group. The median follow-up time was 18.9 months (range 1-102 months) for the entire group. The median follow-up period was longer for RASB group than control group (17 vs 11 months, P = 0.033). The most commonly prescribed RASB agent was valsartan (n = 12/37). At the time of the analysis, 98 (83.7%) of all patients had died. In the univariate analysis, the median OS was longer in the RASB group compared with the control group (17 [±4.1] vs 12 [±1.4] months, P = 0.016). Interestingly, further analyses revealed that RASBs significantly improved OS only if used with erlotinib concurrently (34 [±13.8] vs 25 [±5] months, P = 0.002) and the OS benefit was more attributable to ARBs because only 4 patients received ACEI and erlotinib concurrently. However, the benefit of ARBs on OS disappeared in the multivariate analysis.The use of ARBs during erlotinib treatment may prolong OS of patients with metastatic NSCLC.

Angiotensin-converting enzyme in hypercalcaemic disorders

Serum angiotensin-converting enzyme (SACE) was elevated (mean +/- S.D. 55.2 +/- 19.8 U/ml) in 11 patients with hypercalcaemia due to sarcoidosis, whereas it was within the normal limits ((20.0 +/- 5.2 U/ml) in 23 patients with other hypercalcaemic conditions. Among these, 16 had primary hyperparathyroidism and a SACE level of 18.6 +/- 4.7 U/ml, significantly lower than in healthy controls (24.4 +/- 6.2 U/ml). In 7 patients with hypercalcaemia due to malignancies or prolonged immobilization SACE was 21.8 +/- 5.9 U/ml. A weakly positive correlation was found between SACE and S-calcium in hypercalcaemic sarcoidosis patients but not in the other patients or in a control group of 144 consecutive sarcoidosis patients. sarcoidosis with hypercalcaemia seems to be associated with a very high prevalence of elevated SACE. Especially when sarcoidosis is suspected to be the cause of hypercalcaemia, SACE measurement may be useful as a rapid diagnostic guide.

Serum angiotensin converting enzyme activity in ex-smokers

A low activity of angiotensin converting enzyme (ACE) has been reported in people who smoke. To determine whether this low ACE activity would be reversible on cessation of smoking, we measured serum ACE activity in 107 healthy male volunteers. They included 27 active cigarette smokers, 28 non-smokers, 24 ex-smokers who had stopped smoking for less than 10 yr, and 28 ex-smokers who had stopped smoking for more than 10 yr. The mean value (+/-SD) of serum ACE in those who had stopped smoking for more than 10 yr was comparable to that of non-smokers: 23.2 +/- 5.1 and 23.5 +/- 4.5, respectively. ACE activity in smokers and the ex-smokers who had stopped smoking for less than 10 yr was significantly lower (17.8 +/- 4.5 and 17.8 +/- 3.9, respectively) than values obtained in non-smokers and the group who had not smoked for more than 10 yr (p less than 0.001). These findings suggest that the effect of chronic smoking on the serum ACE activity may be reversible.

Plasma angiotensin-converting enzyme activity in patients with bronchial carcinoma

Plasma angiotensin-converting enzyme (ACE) activities were measured in 58 consecutive patients presenting with bronchial carcinoma. The mean ACE activity before treatment was significantly lower than that of a control population (P less than 0.005). There was a significant and direct relationship between the initial plasma ACE activity and survival time (P less than 0.01) which could not be explained by further analysis for age, clinical staging, or respiratory function, as judged by % FEV. There was a significant increase in plasma ACE activity (P less than 0.03) in nine patients with three or more plasma samples after treatment with chemotherapy or radiotherapy. These results suggest that low plasma ACE activity is associated with poor prognosis in bronchial carcinoma.

The value of serial serum angiotensin converting enzyme determinations in hospitalized patients with lung disease

Abnormal serum angiotensin converting enzyme (ACE) activity has been reported in various human lung disorders and in laboratory animals with acute lung injuries. To test the value of serum ACE activity as an indicator of lung damage and its assistance in diagnosis or prognosis, 328 serum samples were obtained from 108 hospitalized patients with lung disease and 26 normal subjects. When patients were clinically grouped by disease entity, only the sarcoidosis group showed elevated mean serum ACE. Significantly increased serum ACE was found in 17 patients with various lung diseases (15% of hospitalized patients) 12 of whom also had concomitant liver disease. It is hypothesized that the liver may play a role in the normal metabolism of ACE being released by lung endothelial injury. Significantly low levels were seen in many acute and chronic lung injuries; specifically the groups with chronic obstructive lung disease, lung cancer, acute pneumonia, aspiration pneumonitis, gram-negative sepsis, acute myocardial infarction, and congestive heart failure. Serial measures of ACE in 71 patients with lung injuries showed that significantly decreasing levels over successive days were associated with a very high mortality. A single ACE measurement did not predict the presence or extent of lung injury, or aid in diagnosis or prognosis, but serial levels are of value prognostically.

Angiotensin-converting enzyme: an indicator of bleomycin-induced pulmonary toxicity in humans?

In order to evaluate bleomycin-associated lung damage in humans, lung function parameters and serum levels of the endothelial-bound angiotensin-converting enzyme (ACE) were determined by serial measurements in 11 patients who were treated for testicular cancer. None developed clinical or radiological evidence of pulmonary damage. While the static and dynamic lung function parameters were unchanged, carbon monoxide diffusion capacity (DLCO) decreased significantly (P less than 0.01) during a total of 126 days of pulsed regimen, indicating damage to the alveolar-endothelial membrane. S-ACE was unchanged within each treatment course but increased significantly (P less than 0.05) from the initial value to the last treatment course. Two months after cessation of treatment S-ACE returned to pretreatment values. Although the changes were modest they might mirror treatment-associated endothelial damage.

Evaluation of a test kit for the rapid and simple colorimetric measurement of angiotensin I-converting enzyme in serum

We have evaluated a recently introduced colour test kit for the determination of serum angiotensin I-converting enzyme catalytic activity. p-Hydroxyhippuric acid, liberated from p-hydroxyhippuryl-L-histidyl-L-leucine by angiotensin I-converting enzyme, is converted into a quinoneimine dye with an absorption maximum at 505 nm. The procedure shows excellent linearity over the whole range of catalytic activities found in serum. Intra- and inter-assay coefficients of variation are 2-5 and 7-10% respectively. Correlation with a modified Cushman-Cheung ((1971) Biochem. Pharmacol. 20, 1637-1648) method currently used in our laboratory is good, with r = 0.985 and a regression equation of y (colour kit) = 0.423 x (Cushman-Cheung) + 0.765. Haemoglobin, lipids, bilirubin and prednisone do not interfere but uric acid in concentrations higher than 600 mumol/l does. No extraction step is required. The assay is very rapid, and more than twenty samples can be determined in an hour.

[Angiotensin-converting enzyme activity during cytostatic therapy in patients with primary inoperable bronchial carcinoma]

In 43 patients with inoperable bronchogenic carcinoma--32 small cell and 11 squamous or large cell--Angiotensin-Converting-Enzyme (ACE) activity in serum was determined before and every 3-5 weeks during cytotoxic chemotherapy. ACE-activity prior to therapy was 10.7 U +/- 1.17 SE as compared to the normal values 20.4 U +/- 1.8 SE which was statistically significant (p less than 0.01). There was no significant difference between the basal values of patients with small cell and not small cell-carcinoma of the lung. Only for patients with small cell-carcinoma of the lung a significant rise in ACE-activity could be obtained. Mean values of these patients reached normal levels in case they had complete remission, which was achieved in the limited disease group in 82% of patients. The present data suggest, that ACE-activities in serum correspond well to the clinical course in patients with small cell carcinoma of the lung. The decision on the individual mode of therapy may thus become more substantiated by serial determinations of ACE in the course of treatment.